[{"ID":1791,"Name":"Adagdak Older Cone","Description":"From Baten (2002): \"Mt. Adagdak (650 m asl) was built from three stages of volcanism (Figure 1.5 [in original text]).\"\r\n\"The second stage of volcanism resulted in the formation of two composite cones. The older cone formed on the southern portion of the remnant shield and the younger cone formed on the eroded northern flank of the older composite cone (Coats, 1956). Both cones are primarily andesitic in composition.\"\r\n\"...the older cone yields an 40Ar/39Ar date of 2.20 +/- 0.37 Ma (2 sigma error)...\"\r\nFrom Meyers and Frost (1994): \"A prominent break in slope on the southern flank marks the base of an older composite cone formed on top of the earlier shield. Like the latter, this volcanic structure was severely affected by marine erosion and cut back nearly to its center.\"\r\nFrom Coats (1956): \"Older composite cone-Viewed from the south, the long, gentle grass-covered slopes of the shield volcano that forms the substructure of Mount Adagdak are seen to be crowned by the steep, relatively smooth, bare slopes of a wide, low cone. The break in slope occurs at altitudes ranging from 800 to 1,000 feet; the smooth slopes of the upper cone are locally broken by crags developed on small lava flows. This cone represents an older composite cone of Mount Adagdak. It consists largely of lapilli-tuff beds, but includes subordinate lava flows and necks of hornblende andesite. This material accumulated first ns a cone about 800 feet high, the sides of which arc as steep as 26', on the top and the deeply eroded northern flank of the shield volcano. A later explosive episode, centering about a vent northwest of the earlier one, produced an inner, concentrically nested crater, the summit of which was as much as 1,920 feet in altitude, about 200 feet higher than the outer rim. The time interval between the formation of the two craters was probably very short.\"","StartYear":-2198050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":370000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Adagdak","ParentVolcano":"Adagdak","VolcanoID":"ak3","ParentVolcanoID":"ak3"},{"ID":3631,"Name":"Okmok 2100000 yBP","Description":"From Miller and others (1998): \"Construction of the pre-caldera volcano began in late Tertiary or early Quaternary time. Two whole-rock K-Ar analyses of a sample of basaltic lava are 1.7+/-2 and 2.1+/-2 m.y. (Bingham and Stone, 1973). Basaltic flows and pyroclastics compose most of the older rocks (unit Qbm, fig. 67 [in original text]); flows are more voluminous than pyroclastic deposits (see Byers, 1959, plate 41).\"\r\n\"Flows and pyroclastic beds dip radially from the caldera at less than 5 degrees in most sectors, except for local steepening and reversal of dips at former vents. Such radial dips suggest that the older complex was a central volcano with parasitic vents.\"","StartYear":-2098050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":200000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Okmok","ParentVolcano":"Okmok","VolcanoID":"ak206","ParentVolcanoID":"ak206"},{"ID":3641,"Name":"Okmok 1700000 yBP","Description":"From Miller and others (1998): \"Construction of the pre-caldera volcano began in late Tertiary or early Quaternary time. Two whole-rock K-Ar analyses of a sample of basaltic lava are 1.7+/-2 and 2.1+/-2 m.y. (Bingham and Stone, 1973). Basaltic flows and pyroclastics compose most of the older rocks (unit Qbm, fig. 67 [in original text]); flows are more voluminous than pyroclastic deposits (see Byers, 1959, plate 41).\"\r\n\"Flows and pyroclastic beds dip radially from the caldera at less than 5 degrees in most sectors, except for local steepening and reversal of dips at former vents. Such radial dips suggest that the older complex was a central volcano with parasitic vents.\"","StartYear":-1698050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":200000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Okmok","ParentVolcano":"Okmok","VolcanoID":"ak206","ParentVolcanoID":"ak206"},{"ID":2611,"Name":"Jarvis 1630000 yBP","Description":"From Richter and Smith (1976): \"Dacite andesite and dacite flows. Thick sequence of thin to medium flows with minor interbedded tuffs and breccias representing main cone-building stage of Jarvis volcanoes which extend into the McCarthy D-7 and Nabesna A-6 quadrangles. Rocks are dark gray, and pinkish gray. Chiefly two-pyroxene dacitic andesite containing hypersthene, augite, plagioclase, and rare olivine phenocrysts in a felty plagioclase-rich matric. In southwest corner of quadrangle sequence is cut by numerous dark-colored dikes probably chiefly of andesite composition. K-Ar date (M.A. Lanphere, written commun., 1974) on plagioclase indicates age of 1.63+/-0.42 m.y. (Sample 72-ARh-307a).\"","StartYear":-1628050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":420000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Jarvis","ParentVolcano":"Jarvis","VolcanoID":"ak138","ParentVolcanoID":"ak138"},{"ID":2761,"Name":"Kookooligit Mountains 1220000 yBP","Description":"From Mukasa and others (2007): \"Quaternary basalt cinder cones and lava flows form a large shield volcano, over 500 m high, in the north central part of St. Lawrence Island (Kookooligit Mountains). The overwhelming majority of the volcanic rocks at this locality are alkali-olivine basalt, with only subordinate amounts of olivine tholeiite, basanite and minor nephelinite (Patton and Csejtey, 1971; Moll-Stalcup, 1994, 1996). The alkaline basalts are characterized by a high Mg # (61-64), with MgO = 7.9-12.2 wt %, low silica (SiO2=44.8-46.2 wt %), and high total alkalis (Na2O+K2O = 3.8-7.7 wt %) (Moll-Stalcup, 1996). Only one sample (KB-11M) of alkaline olivine basalt has been dated in our study using the 40Ar/39Ar method obtaining a total gas age of 1.32+/-0.02 Ma, plateau age of 1.22+/-0.02 Ma, and isochron age of 1.22+/-0.05 Ma (Figure 4 and Table 1 [in original text]). Moll-Stalcup (1994, 1996) produced K-Ar data for this shield volcano which suggest that volcanic activity in the Kookooligit Mountains continued until 0.24 Ma. Although yet to be verified, combining our 40Ar/39 Ar data with these published K-Ar ages implies that activity continued in a single shield volcano complex for nearly 1 million years.\"","StartYear":-1218050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":50000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kookooligit Mountains","ParentVolcano":"Kookooligit Mountains","VolcanoID":"ak169","ParentVolcanoID":"ak169"},{"ID":1521,"Name":"Capital 1090000 yBP","Description":"From Richter and others (1990): \"Capital Mountain is the erosional remnant of a relatively small andesitic shield volcano with a roughly circular, 4-km-wide summit caldera, filled with more than 900 m of andesite flows (Richter and others 1989). Near the center of the caldera, a prominent volcanic plug is the locus of a postcaldera, predominantly andesitic, radial dike swarm that is unique in the WVF. A rhyolite dike that extends more than 10 km across the shield and caldera, probably represents the last magmatic activity of the volcano. K-Ar ages of 1.02- 1.09 Ma for the andesite shield lavas (nos. 48, 49), andesite dike (no. 50), and rhyolite dike (no. 51) suggest that Capital volcano was active during a relatively short time period as compared to other western WVF volcanoes.\"","StartYear":-1088050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-1018050,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Capital","ParentVolcano":"Capital","VolcanoID":"ak39","ParentVolcanoID":"ak39"},{"ID":3991,"Name":"Jumbo Dome 1026000 yBP","Description":"From Cameron and others (2015): \"Jumbo Dome is a hornblende andesite dome of Pleistocene age located in the Healy Quadrangle of central Alaska, about 19  km northeast of Healy (Albanese, 1980;  Athey and others, 2006) (fig. 1, 2, 3 [in original text]).  Jumbo Dome is approximately 1.6 km  long, 1.3 km wide, and 500  m high and intrudes the Devonian Keevy Peak Formation basement (slate, quartz-sericite schist, graphitic schist, calcareous schist, quartz-feldspar metawacke, and conglomerate) and overlying Tertiary Suntrana Formation (sandstone, clay, and coal) (Albanese, 1980; Wahrhaftig and others, 1969). A single 40Ar/39Ar date of a sample from Jumbo Dome yielded a plateau age of 1.026+/-0.057 Ma (Athey and others, 2006).\"","StartYear":-1024050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":57000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Jumbo Dome","ParentVolcano":"Jumbo Dome","VolcanoID":"ak141","ParentVolcanoID":"ak141"},{"ID":1801,"Name":"Adagdak Younger Cone","Description":"From Baten (2002): \"Mt. Adagdak (650 m asl) was built from three stages of volcanism (Figure 1.5 [in original text]).\"\r\n\"The second stage of volcanism resulted in the formation of two composite cones. The older cone formed on the southern portion of the remnant shield and the younger cone formed on the eroded northern flank of the older composite cone (Coats, 1956). Both cones are primarily andesitic in composition.\"\r\n\"...the younger cone yields a date of 1.02 +/- 0.15 Ma...\"\r\nFrom Meyers and Frost (1994): \"A renewed phase of volcanism produced a younger composite cone on the northern flank of the older, eroded composite cone (Fig. 2 [in original text]).\"\r\nFrom Coats (1956): \"Younger composite cone-A sequence of mudflows consisting largely of fragments of hornblende andesite, capped by two thin hornblende andesite lava flows, makes up the western flanks of Mount Adagdak. These rocks represent a younger cone built after the sea had partly eroded the older composite cone.\"","StartYear":-1018050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":150000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Adagdak","ParentVolcano":"Adagdak","VolcanoID":"ak3","ParentVolcanoID":"ak3"},{"ID":1841,"Name":"Atka 1000000 yBP","Description":"From Meyers and others (2002): \"The youngest phase of volcanism on Atka probably began one to two million years ago and was concentrated around the approximate center of the present volcanic field (Fig. 2 [in original text]). Initial volcanic activity consisted of the eruption of a large number of basalt and basaltic andesite flows. These flows vary in thickness from 1 to 2 m and in some places can be traced laterally for up to 2 km in sea cliffs and the walls of glacial valleys. The large basaltic shield produced by this activity is composed almost exclusively of basalts and basaltic andesites with few pyroclastic units. It probably had an original basal diameter of at least 20 km and a minimum subaerial thickness of 100 m at the volcano margin (Myers and others 1986). Subsequent glacial activity produced large valleys cutting this shield which are radially distributed around the center of the island.\"","StartYear":-998050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-1998050,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Atka volcanic complex","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak17","ParentVolcanoID":"ak17"},{"ID":1451,"Name":"Alagogshak 954000 yBP","Description":"From Hildreth and others (1999): \"...four craggy outliers of ridge-capping andesite 6-10 krn west of the Alagogshak vent (fig. 2 [in original text]) may also have erupted there.\"\r\n\"The northernmost outlier, at peak 3603 on the divide between tributaries of Angle Creek, consists of three, gently northwest dipping, andesite lava flows (57-61 percent SiO2), each as thick as 100 m. Thick flow-breccia and glass columnar zones suggest ice-contact emplacement. The southernmost (and smallest) of the outliers, capping peak 4647 on the divide between Kejulik River and Takayofo Creek, is a single lava flow of silicic andesite (62 percent SiO2) as thick as 200 m. Between them, on the Takayofo-Angle Creek divide, a third outlier consists of coarse flow-breccia and four lava flows, three of which are atypically mafic (52-53 percent SiO2) for Alagogshak and unusually rich in big clinopyroxene and plagioclase phenocrysts. Overlying these on the northwestern spur of the outlier (peak 4281), the fourth lava consists of a 100-m-thick flow of ordinary Alagogshak-type andesite (58 percent SiO2). Finally, the fourth and westernmost outlier, which caps the ridge dividing two tributaries of Takayofo Creek (fig. 2 [in original text]), consists of a single phenocryst-rich andesite lava flow (61-62 percent SiO2), as thick as 200 m. Shew and Lanphere (1992) reported a K-Ar age of 954+/-109 ka for plagioclase separated from this flow.\"","StartYear":-952050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":109000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Alagogshak","ParentVolcano":"Alagogshak","VolcanoID":"ak7","ParentVolcanoID":"ak7"},{"ID":3551,"Name":"Makushin 930000 yBP","Description":"From Miller and others (1998): \"The first episode began in Pliocene or early Pleistocene time (the oldest known age of lavas is 0.93 Ma [Nye, 1990]) and produced extensive flows and subordinate pyroclastic deposits of basaltic and andesitic composition (fig. 61 [in original text]), which enlarged the island by several kilometers along the northwest coast.\"","StartYear":-928050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":3801,"Name":"Redoubt Early Explosive Phase","Description":"From Till and others (1994): \"The lowest deposits exposed record one or more explosive eruptions that produced a small dome or shallow intrusive complex, pyroclastic deposits, and lahar deposits. Magma erupted or intruded during this stage is silicic andesite to dacite in composition; products of the eruption(s) are exposed low on all flanks of the volcano. Where the base of these deposits is exposed, it occurs on granite. A juvenile block from a pyroclastic deposit in the upper part of the deposits that were erupted during this stage yielded a K-Ar age of 0.888 Ma (Table 3 [in original text]). This age is, therefore, a minimum age for the onset of volcanic activity at Redoubt Volcano,\"\r\n\"The lowest exposures on the northwest side of the volcano are composed of interlayered till, fluvial deposits, block-and-ash flow deposits, and pumiceous pyroclastic flow deposits that dip shallowly to the north. The base is obscured. Clasts in the block-and-ash and pumice flows are silicic andesite in composition (62.0-62.7% SiO2).\"\r\n\"Two pyroclastic units have been differentiated. The lower unit (Qxp) is composed predominantly of till and fluvial sediments. However, pumiceous pyroclastic flow deposits composed of hornblende-bearing white pumice in a light-gray or light-brown ash matrix are interlayered with the sediments and are exposed on several ridges. Correlations between ridges are difficult, but least two emplacement units occur on most ridges, and two separate exposures of substantially thick units exist. The thicker flow is 24-30 m thick, indurated, and consists of 50-70% white subangular to subrounded horn-blende-beating pumice clasts, less than 2% light-gray hornblende-phyric juvenile lithic fragments, and a light-gray fine ash matrix. Locally, the deposit is clast supported. The largest pumice clasts, 45-60 cm in diameter, occur at the base of the flow. Most pumice clasts are less than 10 cm across and are normally graded. Grading of the juvenile lithic clasts was not noted. A 2-4- cm-thick layer of fine ash is concentrated at the base of the flow (Fig. 5 [in original text]). Several centimeters of laminated lapilli and ash occur at the top of the flow. Above the laminated ash, locally there are thin beds of strongly graded lapilli to ash-sized material, some of which may be primary airfall tephra. A second pyroclastic flow deposit, 15 m thick where exposed, is quite similar. It also has fine ash concentrated at its base and top, and the coarsest pumice clasts (10 cm in diameter) concentrated at the bottom. Pumice clasts in the main body of the deposit are pebble-sized and appear to be unsorted. This deposit contains 40% subangular to subrounded pumice clasts, 15% subangular to subrounded juvenile lithic clasts, and 45% matrix of light-brown ash-sized particles. Thinner (3 cm-2 m) pumiceous pyroclastic flow deposits are clast or matrix supported, contain rare lithic clasts, and commonly are overlain by laminated beds of fine ash.\"\r\n\"Above the sediments and interlayered pumice flow deposits, at least two block-and-ash flow deposits occur. Both are matrix supported and contain clasts of juvenile hornblende-phyric silicic andesite, some of which are radially fractured or are bombs. The matrix is sand-sized and crystal-rich. In general, the relative amount of volcanic material increases up section.\"\r\n\"The upper unit (Qxb) is dominated by block- and-ash flow deposits and contains subordinate fluvial deposits. Numerous poorly consolidated to unconsolidated block-and-ash flow deposits 0.5-60 m thick are distinguished in section by variations in matrix color or intervening concentrations of fine ash. Most emplacement units are internally unstructured and do not show sorting. Some emplacement units contain graded beds, cross bedding, and concentrations of granitic clasts that suggest the unit was reworked by water. Clasts are dominantly subangular to subrounded reddish-gray to light-gray hornblende-phyric silicic andesite (juvenile), but also include minor granitic clasts and scoriaceous basalt (dark-gray clinopyroxene-phyric flow rock). Pumice occurs rarely in some units. The largest juvenile lithic clasts observed were 2-3 m in diameter and were concentrated at the base of an emplacement unit. The matrix of most units is sand-sized and crystal-rich; rare pumiceous sand-sized grains are present. A large, glassy juvenile hornblende-phyric silicic andesite clast from one of these block-and-ash flow deposits yielded a K-Ar age of 0.888 Ma (Table 3; locality 1, Fig. 3 [in original text]).\"","StartYear":-886050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":63000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Redoubt","ParentVolcano":"Redoubt","VolcanoID":"ak231","ParentVolcanoID":"ak231"},{"ID":3191,"Name":"Wrangell 878000 yBP","Description":"From Richter and others (1990): \"A dacite flow (0.88 Ma, [sample] no. 3) listed as a Mount Wrangell lava (Table 2 [in original text]) may be a late product of the Chetaslina center.\"","StartYear":-876050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":17000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Wrangell","ParentVolcano":"Wrangell","VolcanoID":"ak326","ParentVolcanoID":"ak326"},{"ID":3361,"Name":"Togiak volcanics 760000 yBP","Description":"From Hoare and Coonrad (1980): \"The Togiak Basalt consists largely of undeformed subaerial tholeiite and alkali-olivine basalt flows (table 1 [in original text]) characterized by well-developed columnar jointing and generally 3 m to 10 m thick with vesicular ropy tops. The columns are generally 1 to 2 m in diameter but are smaller in the finer grained flows. Most of the flows are gray, medium-grained, nonporphyritic rock with a loose diktytaxitic texture; some flows are dense fine-grained black rock with small olivine phenocrysts. The flows consist of labradorite, augite, olivine, and accessory magnetite. The fine-grained darker flows also have interstitial glass.\"\r\nFrom Hoare and others (1978): \"The widespread flows on the valley floor are preglacial in age. They apparently erupted from vents that were localized along the faults. Most of the older volcanic vents were probably destroyed by glacial ice, and only one of them has been identified. It is located about 11 km northeast of the tuya on a small shelf that projects out from the valley wall about 170 m above the valley floor (fig. 2 [in original text]). The shelf is underlain by highly oxidized, vesicular breccia, the probable remnant of an old preglacial cone. The location and elevation of the cone remnant suggest vertical uplift on the Togiak fault. A second, larger shelf at about the same elevation projects out from the valley wall east of the tuya. This shelf is underlain by horizontal flows. The flows and shelf can be traced up a tributary valley where the flows overlie highly deformed rocks of Mesozoic (Jurassic?) age. We conclude that there has been about 170 m. of vertical movement on the Togiak fault since the flows erupted on the valley floor.\"\r\n\"The radiometric age of a flow on the valley floor 20 km north of the tuya was determined by the potassium- argon method to be 0.76+/-0.2 million years (J. G. Smith, written commun., 1976).\"\r\n\"We determined the magnetic polarity of the flows on the valley floor and on the tuya at several places and found that all of the flows are normally magnetized. The polarity of the flows and the radiometric age determination indicate that the flows on the valley floor erupted near the beginning of the present (Brunhes) polarity epoch, which began approximately 700 000 years ago (Cox and others, 1963).\"\r\n\"The tuya is clearly younger than the flows on the valley floor because it overlies them.\"","StartYear":-758050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":200000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Togiak volcanics","ParentVolcano":"Togiak volcanics","VolcanoID":"ak286","ParentVolcanoID":"ak286"},{"ID":4021,"Name":"Makushin Eider Point Flow","Description":"From Nye and others (1986): \"The one dated Eider Point flow is younger, at 0.69+/-0.06 m.y.\"","StartYear":-688050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":60000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":1491,"Name":"Blue Mtn Domes","Description":"From Hildreth and others (2007): \"The main central dome of Blue Mountain yields an 40Ar/39 Ar age of 632+/-7 ka...\"\r\n\"A single 40 Ar/39 Ar age was determined for Blue Mountain, on a groundmass concentrate of dacite sample U-19 (table 1 [in original text]) from the south-trending ridge of summit Dome 1776 (figs. 3A, 6 [in original text]). Its weighted-mean plateau age is 632+/-7 ka (fig. 9; table 2 [in original text]), categorically middle Pleistocene and about 25 times older than the lithologically and compositionally similar domes at The Gas Rocks. At Blue Mountain, the several satellitic domes surrounding dated Dome 1776 (fig. 3 [in original text]) are unlikely to differ much in age, although the noncontiguous northern group might conceivably do so. We discerned no significant differences in degree of erosion, and the chemical and petrographic similarities of nearly all the domes in both groups suggest no basis for inferring an exceptionally protracted eruptive sequence.\"\r\n\"Present-day volumes of the Blue Mountain domes have been estimated, recognizing that at least 20 percent of the initial lavas, and a completely unknown pyroclastic volume, have been glacially eroded away. The noncontiguous northern cluster of three small domes totals ~60 million m cubed in volume. The central mass of the main cluster, including Domes 1776 and 1700 (fig. 3A [in original text]), totals ~500 million m cubed in volume, and its satellites’ volumes are estimated as follows: easterly Dome 1572, ~180 million m cubed; the three small southerly domes, 35 to 45 million m cubed each; westerly Dome 1600, ~160 million m cubed; and crystal-poor northerly Dome 1200, ~35 million m cubed. These estimates provide a total surviving volume of 1.05 km cubed of Blue Mountain dacite.\"","StartYear":-630050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":7000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Blue Mtn","ParentVolcano":"Blue Mtn","VolcanoID":"ak27","ParentVolcanoID":"ak27"},{"ID":2221,"Name":"Drum Tetlin Tephra","Description":"From Schaefer (2002): \"Tephra sample 96TOK-1-9 (Tetlin Tephra), in the lower part of the section has an age of 627.5+/-47.7 ka (40Ar/39Ar age of hornblende, this study)...this tephra does not correlate definitively with any tephras that have been dated in interior Alaska or the Yukon...\"\r\n\"The thickness of the Tetlin Tephra indicates its deposition was the result of a large explosive eruption. Its composition (highly inflated pumice with abundant euhedral hornblende) matches that of the hornblende dacites described on Mount Drum (Richter and others, 1994). The results of 40Ar/39Ar dating indicate that the deposition of the Tetlin Tephra occurred approximately 627 ka. Based on published geologic descriptions and geochemistry of the Wrangell volcanic field, the most likely candidates for proximal correlation are the 650 to 400 ka silicic domes that are found on the east and southeast flank of Mount Drum volcano.\"\r\n\"Based on age and composition, the 650 to 400 ka eruptive sequence of Mount Drum is the most likely source for the 627-ka Tetlin Tephra. Between 650 and 400 ka, a group of four silicic domes were emplaced on the east and southeast flank of the volcano (K-Ar whole rock ages by Richter and others, 1994). These rhyodacite domes are porphyritic, consisting of brown hornblende, plagioclase, and rare to common hypersthene, biotite, and augite, much like the composition of Tetlin Tephra. All rocks analyzed from Mount Drum have type II rare earth element characteristics: they are LREE-enriched, having La/Yb between 9 to 25 (Richter and others, 1994). No other Wrangell source vents have documented eruptive products or the right age constraints to match the age and composition of the Tetlin Tephra other than the Mount Drum domes. The Tetlin Tephra likely represents an early explosive phase of activity associated with the emplacement of these 650 to 400 ka, petrologically similar domes.\"","StartYear":-625550,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":47700,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Drum","ParentVolcano":"Drum","VolcanoID":"ak81","ParentVolcanoID":"ak81"},{"ID":2851,"Name":"Lone basalt 593000 yBP","Description":"From Hildreth and others (2007): \"Wilson and Shew (1992) determined a whole-rock K-Ar age of 593+/-73 ka for the Lone basalt.\"","StartYear":-591050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":73000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Lone basalt","ParentVolcano":"Lone basalt","VolcanoID":"ak339","ParentVolcanoID":"ak339"},{"ID":1321,"Name":"Akutan Long Valley Series","Description":"From Richter and others (1998): \"The oldest of the satellite centers is the Long Valley series of linear and monolithologic domes or very shallow intrusions and carapace(?) breccias dated at 0.58 Ma.\"","StartYear":-578050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":2841,"Name":"Kupreanof 570000 yBP","Description":"From Wilson and others (1989): \"Two mafic andesite flows from Kupreanof volcano yield ages of 0.57 Ma (locality 15, table 3 [in original text]) and approximately 2.1 Ma (Nora Shew and F.H. Wilson, unpub. data, 1988). Although these two flows are virtually identical chemically, the younger of the two flows is orthopyroxene, clinopyroxene, and olivine bearing whereas the older contains only clinopyroxene as a mafic phase.\"","StartYear":-568050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kupreanof","ParentVolcano":"Kupreanof","VolcanoID":"ak175","ParentVolcanoID":"ak175"},{"ID":3481,"Name":"St. Paul Island 540000 yBP","Description":"From Winer and others (2004): \"The earliest subaerial volcanic activity on St. Paul Island is recorded in several stacks of horizontal to subhorizontal basaltic lava flows with only small amounts of intervening tephra (map unit UPL; Figs. 2 and 4A [in original text]). The most complete and accessible exposures of the platform lavas occur at four locations: (1) Reef Point, the southernmost part of the island. (2) Tolstoi Point on southern St. Paul; (3) Zapadni Point on the southwestern coast; and (4) Einahnuhto Bluffs along the west coast (Fig. 2 [in original text]). The absolute duration of this phase and the relative stratigraphic order of lava flow packages at the different localities are largely speculative because we have few ages (three samples produced unresolvable results) and there are few mutual contacts. Available age data from flows at Southwest Point (SP98-39) and Einahnuhto Bluffs (SP98-25, SP98-22) are from 540 to 400 ka (Table 1 [in original text]). These ages are consistent with the observation of Cox and others (1966) who determined that all volcanic rocks on St. Paul erupted during the Bruhnes Chron of normal polarity.\"\r\n\"At the first three locations listed above, vertical sections of flat to gently tilted pahoehoe lava flows are exposed from sea level to the tops of the volcanic piles at elevations ranging from 25 to 40 m (Fig. 4A [in original text]). Lava flows are both compound and simple and are often laterally discontinuous over short distances. Ropy flow surfaces and vesicular flow tops are commonly preserved and pipe vesicles occur in flow bases. Evidence for emplacement of platform lavas by tube flow is present at several localities. Source vents for the platform lavas were not identified, suggesting eruption either from initially high-standing, but now eroded cones, or, more likely, from low-profile shields or fissure systems presently buried beneath younger volcanic units (Barth, 1956; Winer, 2001).\"\r\n\"Thicknesses of the early platform lava flows on Tolstoi Point range from 0.5 to 15 m with thinner compound flows at the bottom of the section and thicker, massive flows at the top. For example, the highest exposed flow at Tolstoi Point is a massive simple flow (~15 m thick) with distinctive horizontal platy jointing; this jointing contrasts with the vertical jointing in thin, lower flows (Fig. 5 [in original text]). A similar, thick (~25 m), massive flow with platy jointing is exposed on the highest level of the steep, southwest facing cliff at Zapadni Point (Fig. 6A [in original text]). The stratigraphy of the platform lavas at Einah-nuhto Bluffs is more complex than on Tolstoi Point and Zapadni Point (Fig. 6B [in original text]). Among the lower units at Einahnuhto Bluffs is a basaltic lava flow that appears to have intruded wet marine sediments. Evidence for this is the presence of pillow-like pods of lava, some as great as 2 m in diameter, embedded in a brecciated matrix of quenched and hydrofractured basaltic lapilli and tuff plus sandy sediments (Fig 7 [in original text]). This unit is interpreted as a peperite formed during intrusion and quenching of basaltic magma in water-saturated sediments (Kokelaar, 1986). Overlying this unit are numerous compound pahoehoe lava flows similar to those described at other platform lava exposures.\"\r\n\"The style of eruptions and emplacement of platform lavas on St. Paul Island appear to be similar to that described by Greeley (1977a) and Hughes and others (1999) for basaltic ‘‘plains-style’’ volcanism of the eastern Snake River Plain, USA. Specifically, the following features of plains-style volcanism are also characteristics of early subaerial volcanic deposits on St. Paul (Greeley, 1977a; Hughes and others, 1999): (1) volcanic units are generally small volume basaltic lavas that appear to have erupted effusively from fissures or low-profile shields; (2) lavas are mostly compound pahoehoe flows erupted at low effusion rates, but with a few simple flows produced during periods of higher effusion rates (Walker, 1972); (3) lavas are often emplaced via lava tubes and lava channels, forming rather flat topography; and (4) jointing is either vertical due to cooling or sub-horizontal and platy due to flow-induced shear.\"","StartYear":-538050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-398050,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"St. Paul Island","ParentVolcano":"St. Paul Island","VolcanoID":"ak264","ParentVolcanoID":"ak264"},{"ID":3451,"Name":"Stepovak Bay 1, 1530000 yBP","Description":"From Wilson (1989): \"Age determinations were attempted on three young andesite flows from volcano 1. An age of 0.53 Ma (locality 6, table 3 [in original text]) was obtained on a sample from volcano 1.\"","StartYear":-528050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Stepovak Bay 1","ParentVolcano":"Stepovak Bay 1","VolcanoID":"ak303","ParentVolcanoID":"ak303"},{"ID":1471,"Name":"Basalt of Gertrude Creek","Description":"From Hildreth and others (2004): \"Basalt of Gertrude Creek makes up a 1-km-wide remnant of an ejecta cone and lava-flow apron that form a glacially smoothed domical swell about 5 km NE of Becharof Lake (Fig. 1 [in original text]), near the trace of the Bruin Bay Fault (Riehle and others 1993). Surviving outcrop has about 60 m of gentle relief and includes a 200-m-wide degraded crater now only 5 to 8 m deep, rimmed by brick-red scoria blocks and sheets of blobby agglutinate that are broken and frost-heaved into slabs. Outside the rim is a frost-disrupted apron of blocks and slabs of dark-gray, massive to finely vesicular, basaltic lava. The subalkaline high-alumina basalt (49.8% SiO2, 6.8% MgO) contains abundant small phenocrysts of olivine, cpx, and plagioclase, and inclusions (in olivine) of Cr-spinel. A slab of holocrystalline lava near the north rim gave a 40 Ar/39Ar plateau age of 500+/-14 ka (Hildreth and others 2003b).\"","StartYear":-500000,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":14000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Basalt of Gertrude Creek","ParentVolcano":"Basalt of Gertrude Creek","VolcanoID":"ak21","ParentVolcanoID":"ak21"},{"ID":3161,"Name":"Yantarni 460000 yBP","Description":"From Riehle and others (1987): \"A sample of the basal cone deposits on the north side of the cone yielded a K-Ar age of 0.46k[+/-]0.12 Ma (sample 77, table 3 [in original text]), thus the onset of the cone- building phase of volcanism overlaps or closely succeeds the closing stages of early lava-flow activity.\"","StartYear":-458050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":120000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Yantarni","ParentVolcano":"Yantarni","VolcanoID":"ak328","ParentVolcanoID":"ak328"},{"ID":3171,"Name":"Yantarni 410000 yBP","Description":"From Riehle and others (1987): \"Another sample of a lava flow stratigraphically high in the cone-building deposits yielded an age of 0.41k[+/-]0.09 Ma (sample 19, table 3 [in original text]). The cone retains the outline of its original form (see frontispiece [in original text]) but is incised in all quadrants by glacially eroded valleys, and we infer that cone construction was largely completed before late Pleistocene glaciation. The inference is consistent with the youngest radiometric age of the sample that is stratigraphically high in the cone-building unit (0.41 Ma; sample 19).\"","StartYear":-408050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":90000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Yantarni","ParentVolcano":"Yantarni","VolcanoID":"ak328","ParentVolcanoID":"ak328"},{"ID":1621,"Name":"Emmons first CFE","Description":"From Waythomas and others (2006): \"The age of earliest volcanism is unknown, but it is likely that the center was intermittently active for several hundreds of thousands of years before the first caldera forming eruption occurred about 400,000 years B.P.\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2017) reports a magnitude of 4, bulk eruptive volume of 0.1 cubic km and a dense rock equivalent eruptive volume of 0.04 cubic km for the eruption.","StartYear":-398050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Emmons Lake Caldera","ParentVolcano":"Emmons Lake Volcanic Center","VolcanoID":"ak92","ParentVolcanoID":"ak93"},{"ID":3461,"Name":"Stepovak Bay 1, 1400000 yBP","Description":"From Wilson (1989): \"Age determinations were attempted on three young andesite flows from volcano 1...A second sample has yielded a preliminary age of 0.4 Ma (Nora Shew and F.H. Wilson, unpub. data, 1988).\"","StartYear":-398050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Stepovak Bay 1","ParentVolcano":"Stepovak Bay 1","VolcanoID":"ak303","ParentVolcanoID":"ak303"},{"ID":3001,"Name":"Rainbow River cone 390000 yBP","Description":"From Hildreth and others (2007): \"An ice-scoured lava plateau (390+/-39 ka) extends 1 km SE from the cone.\"","StartYear":-388050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":39000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Rainbow River cone","ParentVolcano":"Rainbow River cone","VolcanoID":"ak228","ParentVolcanoID":"ak228"},{"ID":4031,"Name":"Makushin 380000 yBP","Description":"From Nye and others (1986): \"Flows west of Driftwood are substantially younger; a stratigraphically high flow is 0.38+/-0.04 m.y...\"","StartYear":-378050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":40000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":3491,"Name":"St. Paul Island Crater Hill flow","Description":"From Winer and others (2004): \"The oldest 40Ar/39Ar age obtained on a monogenetic volcano is 360+/-80 ka for a lava flow erupted from Crater Hill. The age of the Crater Hill flow represents a minimum for development of the monogenetic centers because older, undated cones are present overlying the platform lavas on the south-central part of the island, from Telegraph Hill southward. The craters of the older cones have been obliterated by erosion and breaching, and some have experienced major mass wasting where exposed to heavy surf. In contrast, morphologically young monogenetic cones on the central highland have relatively sharp profiles and well preserved craters.\"","StartYear":-358050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":80000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"St. Paul Island","ParentVolcano":"St. Paul Island","VolcanoID":"ak264","ParentVolcanoID":"ak264"},{"ID":4141,"Name":"Wrangell Debris Avalanche","Description":"From Waythomas and Wallace (2002): \"An areally extensive volcanic mass-flow deposit of Pleistocene age, known as the Chetaslina volcanic mass-flow deposit, is a prominent and visually striking deposit in the southeastern Copper River lowland of south-central Alaska. The mass-flow deposit consists of a diverse mixture of colorful, variably altered volcanic rocks, lahar deposits, glaciolacustrine diamicton, and till that record a major flank collapse on the southwest flank of Mount Wrangell...Deposits of the Chetaslina volcanic mass flow in the Chetaslina River drainage are primary debris-avalanche deposits and consist of two principal facies types, a near-source block facies and a distal mixed facies. The block facies is composed entirely of block-supported, shattered and fractured blocks with individual blocks up to 40 m in diameter. The mixed facies consists of block-sized particles in a matrix of poorly sorted rock rubble, sand, and silt generated by the comminution of larger blocks. Deposits of the Chetaslina volcanic mass flow exposed along the Copper, Tonsina, and Chitina rivers are debris-flow deposits that evolved from the debris-avalanche component of the flow and from erosion and entrainment of local glacial and glaciolacustrine diamicton in the Copper River lowland. The debris-flow deposits were probably generated through mixing of the distal debris avalanche with the ancestral Copper River, or through breaching of a debris-avalanche dam across the ancestral river. The distribution of facies types and major-element chemistry of clasts in the deposit indicate that its source was an ancestral volcanic edifice, informally known as the Chetaslina vent, on the southwest side of Mount Wrangell. A major sector collapse of the Chetaslina vent initiated the Chetaslina volcanic mass flow forming a debris avalanche of about 4 km3 that subsequently transformed to a debris flow of unknown volume.\"\r\n\"Analysis of a single pumice pyroclast in the pyroclasticflow\r\ndeposit (Fig. 8 [in text]) gave a K-Ar age of 342 ± 16 ka (D.H.Richter, personal communication, 2000 and unpublished data), and we consider this a maximum-limiting age for the debris avalanche. In the upper Chetaslina River drainage, debrisavalanche deposits are overlain by a lava flow that yielded a K-Ar age of 270 ± 40 ka (Nye 1983). Thus, the debris avalanche probably formed between about 340 and 270 ka.\"","StartYear":-340050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":16000,"StartQualifierUnit":"Years","EndYear":-268050,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":40000,"EndQualifierUnit":"Years","Volcano":"Wrangell","ParentVolcano":"Wrangell","VolcanoID":"ak326","ParentVolcanoID":"ak326"},{"ID":4041,"Name":"Makushin Point Kovrishka flows","Description":"From Nye and others (1986): \"The youngest dated Pleistocene flows are from the Point Kovrishka area and are 0.30+/-0.02 to 0.34+/-0.04 m.y.\"","StartYear":-338050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":40000,"StartQualifierUnit":"Years","EndYear":-298050,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":20000,"EndQualifierUnit":"Years","Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":3791,"Name":"Redoubt Cone Building Stage","Description":"From Till and others (1994): \"Basalt and basaltic andesite lava flows and flow breccia form the lower part of the present cone at Redoubt Volcano. The flows occur as high as 2560 m on the northeast flank of the mountain, so the cone stood at least that high at the culmination of the early cone-building stage (1000-1200 m above the base). Because the lava flows crop out on all sides of the volcano and are distinctive in appearance, they are useful as a stratigraphic marker horizon. Three K-Ar ages on samples from lava flows generated during this stage have been obtained (Table 3 [in original text]). Because the relative stratigraphic position of the lava flows is not known, the full time span of the early cone-building stage has not been determined. It apparently spanned a period from at least 0.340+/-0.01 Ma to 0.184+/-0.012 Ma.\"\r\n\"One andesite flow on Redoubt Creek crops out among deposits of the early cone-building stage. The base of the flow is not exposed, but basaltic pyroclastic deposits of the early cone-building stage sit on either side of it. The andesite flow is petrographically and chemically different from most of the flows and clasts in the block-and-ash flows formed during this stage, however. It contains less than 5% phenocrysts and 2% more SiO2 than the next most silicic flow erupted during the early cone-building stage. A whole-rock K-Ar date gives an age of 0.193+/-0.008 Ma (locality 38, Table 3 [in original text]), close to that obtained from a flow more typical of the early cone-building stage, so it has been included in that stage. Because its chemical composition is atypical of the stage, it is separately designated on plots of chemical data (see Figs. 10, 11 [in original text]).\"\r\n\"The early cone-building stage produced voluminous flows, flow breccia, and pyroclastic deposits that built the cone up to a minimum of 1000 m above its base. The thickest exposures of early cone-building units are on the north side of the volcano and may indicate that activity was concentrated on that side.\"","StartYear":-338050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":10000,"StartQualifierUnit":"Years","EndYear":-182050,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":12000,"EndQualifierUnit":"Years","Volcano":"Redoubt","ParentVolcano":"Redoubt","VolcanoID":"ak231","ParentVolcanoID":"ak231"},{"ID":2241,"Name":"Drum Pre-Snider Peak Flows","Description":"From Richter and others (1994): \"The final stages of cycle 2 constructional volcanic activity probably occurred in the vicinity of Snider Peak on the south flank of Mount Drum (Fig. 3 [in original text]). Extensive dacite lava flows were erupted here at about 300 ka (samples G, E, Fig. 4 [in original text]) followed by the emplacement of the Snider Peak dacite dome at about 250 ka (sample A, Fig. 4 [in original text]).\"","StartYear":-298050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Drum","ParentVolcano":"Drum","VolcanoID":"ak81","ParentVolcanoID":"ak81"},{"ID":1851,"Name":"Atka CFE-Big Pink","Description":"From Meyers and others (2002): \"After this initial activity, the central cone, Atka Volcano, grew on top of the shield and probably reached an elevation of ~2,200 m. A series of satellite vents then formed, ringing the central cone (Fig. 2 [in original text]). These volcanic edifices are comprised of lava flows as well as pyroclastic units including many lahars. The increase in the abundance of pyroclastic rocks as well as the change in the dominant lava from basalt to andesite differentiates these later volcanic vents from the earlier, shield building stage. Summit glaciers have breached many of the summit craters, thereby forming active cirques which dissect many of the satellite vents.\"\r\n\"Ancestral Atka Volcano subsequently collapsed, creating a caldera 5 km in diameter (Fig. 2 [in original text]). Associated with this event was the eruption of a large dacitic flow (Fig. 3 [in original text]). This flow, called Big Pink because of its distinctive field appearance, is approximately 400 m thick, nearly oval in outline and 2-3 km in maximum dimension (Fig. 2 [in original text]). It consists of pumiceous and glassy units but is not associated with any ash flows. A hydration date from Big Pink suggests the caldera-forming eruption of ancestral Atka Volcano occurred 300,000 to 500,000 years ago (Marsh, unpublished data). A series of NW-trending dikes cuts the entire Atka Volcano shield and was presumably emplaced during caldera formation (Fig. 2 [in original text]). The dikes are nearly vertical and approximately 1 m thick.\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2016) reports a magnitude of 4.0, bulk eruptive volume of 0.10 cubic km and a dense rock equivalent eruptive volume of 0.040 cubic km for the eruption.","StartYear":-298050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-498050,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Atka volcanic complex","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak17","ParentVolcanoID":"ak17"},{"ID":1631,"Name":"Emmons Leontovich welded tuff","Description":"From Waythomas and others (2006): \"Major Plinian/ultra-Plinian eruption. Extensive ignimbrite sheets.\"\r\n\"Major explosive events with high column of ash and pyroclastic debris. Extensive ash dispersal and formation of mobile and far traveling pyroclastic flows.\"\r\n\"Eruptive product studies associated with caldera formation date the major eruptions around 294,000, 234,000, 123,000, 100,000, 30-50,000, and 26,000 years ago. Each of these eruptions produced relatively extensive pyroclastic-flow deposits of dacite to rhyolite composition hot enough to weld when deposited and form the welded tuff units shown in figures 7 and 8 [in original text]. Some of the welded tuffs show evidence of secondary flowage (rheomorphic tuffs) as far as 35 km from their source calderas (fig.8 [in original text]). Rheomorphic welded tuffs are unique to the Emmons Lake volcanic center and are found nowhere else in the Aleutian arc. The welded tuffs crop out in areas southeast and northeast of the caldera complex where they flowed into and filled preexisting valleys and ancestral drainages.\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2017) reports a magnitude of 4, bulk eruptive volume of 0.10 cubic km and a dense rock equivalent eruptive volume of 0.040 cubic km for the eruption.","StartYear":-292050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Emmons Lake Caldera","ParentVolcano":"Emmons Lake Volcanic Center","VolcanoID":"ak92","ParentVolcanoID":"ak93"},{"ID":3371,"Name":"Togiak volcanics 263000 yBP","Description":"From Kaufman and others (2001): \"To more closely date the tuya eruption, we performed single-step, laser-fusion 40 Ar/39Ar analyses on a capping basalt flow. The dated sample (DK95-17; Fig. 2 [in original text]) was collected from near the base of the subaerial flows, about 17 m above the well-exposed pillow lava described above. We choose to date basalt that erupted subaerially to avoid potential complications of incomplete degassing of the chilled pillows. In selecting subsamples for laser fusion, phenocrysts (another potential source of excess Ar) were avoided and groundmass-rich subsamples were dated (cf. McDougall and Harrison, 1988). Six sub-samples yielded a weighted average age of 263+/-22 ka (Table 4 [in original text]). They averaged 85% atmospheric Ar content, which, together with visual inspection, indicates that the basalt is not signicantly altered. The isotopic compositions of the subsamples varied only slightly, indicating anisotopically homogeneous sample, but precluding precise isochron determination of the age. Because we found no evidence for deposition or erosion separating the pillow lava from the capping subaerial flow, we believe that 40Ar/39Ar age closely limits the age of the glacial lake. The age also overlaps with the amino acid age estimate of the youngest aminozone on Hagemeister Island, indicating that the eruption of the tuya may have partially overlapped with the deposition of glacial-marine sediment in Togiak Bay.\"","StartYear":-261050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":22000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Togiak volcanics","ParentVolcano":"Togiak volcanics","VolcanoID":"ak286","ParentVolcanoID":"ak286"},{"ID":1331,"Name":"Akutan Flat Top Center","Description":"From Richter and others (1998): \"The largest of the satellite centers is the Flat Top center located southwest of the Akutan caldera and dated at 0.25 Ma. It consists of relatively extensive lava flows, a vent breccia complex, and a radial dike swarm.\"","StartYear":-248050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":2231,"Name":"Drum Snider Peak","Description":"From Richter and others (1994): \"The final stages of cycle 2 constructional volcanic activity probably occurred in the vicinity of Snider Peak on the south flank of Mount Drum (Fig. 3 [in original text]). Extensive dacite lava flows were erupted here at about 300 ka (samples G, E, Fig. 4 [in original text]) followed by the emplacement of the Snider Peak dacite dome at about 250 ka (sample A, Fig. 4 [in original text]).\"\r\nFrom Westgate and others (2007): \"Large volumes of mostly andesitic lava were erupted, building a large volcanic pile. Several dacite domes formed towards the end of this cycle, including Snider Peak, which is 240 ka and probably represents the last products of constructional volcanic activity on Mount Drum (Richter and others, 1994).\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2017) reports a magnitude of 4.000 , bulk eruptive volume of 0.100 cubic km and a dense rock equivalent eruptive volume of 0.040 cubic km for the eruption.","StartYear":-248050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Drum","ParentVolcano":"Drum","VolcanoID":"ak81","ParentVolcanoID":"ak81"},{"ID":3381,"Name":"Tanaga 240000 yBP","Description":"From Coombs and others (2007): \"The edifice was once much larger than it is today and probably was centered between Tanaga and Takawangha. A broadly crescent-shaped scarp, concave to the west, separates the Takawangha and Tanaga edifices. This ridge is thought to be the residual rim of an amphitheatre that formed as the older volcanic edifice partially collapsed, as a debris avalanche, into the sea (fig. 11 [in original text]). On the basis of radiometric dates of lava flows on either side of the collapse scar, this event occurred between 240,000 and 118,000 years ago. Similar collapses have been recognized for other Aleutian volcanoes that sit on the north edge of the underwater Aleutian ridge (Coombs and others, 2007). Although many volcanic collapses of this kind are accompanied by eruptions, no widespread eruptive deposit has been correlated to the Tanaga collapse. This information indicates either such a deposit has been erased by erosion, or the collapse was caused by gravitational instability of the growing volcano, until the volcano finally gave way and fell into the sea.\"\r\nFrom Coombs and others (2007): \"Lavas from the pre-Tanaga volcano that form the amphitheatre wall have been dated using 40 Ar/39Ar at 240 ka; the oldest lavas west of this scarp underlie the current Tanaga cone and have been dated at 140 ka, thus constraining amphitheatre formation to 240-140 ka (A. Calvert, unpublished data). This age is consistent with the eroded, scalloped morphology of the collapse scarp, which appears modified by glaciation. No extensive pyroclastic sheet or tephra was found that could correlate to caldera formation; however, glaciation may have destroyed evidence of such a deposit.\"","StartYear":-238050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-116050,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Tanaga","ParentVolcano":"Tanaga","VolcanoID":"ak280","ParentVolcanoID":"ak280"},{"ID":1561,"Name":"Cone 3110","Description":"From Hildreth and others (2004): \"The upper third of the cone (235+/-30 ka) is coherent lava, columnar to chunky jointed. Products have abundant plagioclase, cpx, and olivine, with minor opx.\"","StartYear":-233050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":30000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cone 3110","ParentVolcano":"Cone 3110","VolcanoID":"ak54","ParentVolcanoID":"ak54"},{"ID":1641,"Name":"Emmons Lake Volcanic Center CFE I-C1/Cathedral Welded Tuff","Description":"From Waythomas and others (2006): \"Major Plinian/ultra-Plinian eruption. Extensive ignimbrite sheets.\"\r\n\"Major explosive events with high column of ash and pyroclastic debris. Extensive ash dispersal and formation of mobile and far traveling pyroclastic flows.\"\r\n\"Eruptive product studies associated with caldera formation date the major eruptions around 294,000, 234,000, 123,000, 100,000, 30-50,000, and 26,000 years ago. Each of these eruptions produced relatively extensive pyroclastic-flow deposits of dacite to rhyolite composition hot enough to weld when deposited and form the welded tuff units shown in figures 7 and 8 [in original text]. Some of the welded tuffs show evidence of secondary flowage (rheomorphic tuffs) as far as 35 km from their source calderas (fig.8 [in original text]). Rheomorphic welded tuffs are unique to the Emmons Lake volcanic center and are found nowhere else in the Aleutian arc. The welded tuffs crop out in areas southeast and northeast of the caldera complex where they flowed into and filled preexisting valleys and ancestral drainages.\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2017) reports a magnitude of 6.7, bulk eruptive volume of 50 cubic km and a dense rock equivalent eruptive volume of 21.8 cubic km for the eruption.","StartYear":-232050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Emmons Lake Caldera","ParentVolcano":"Emmons Lake Volcanic Center","VolcanoID":"ak92","ParentVolcanoID":"ak93"},{"ID":1811,"Name":"Adagdak Domes","Description":"From Baten (2002): \"Mt. Adagdak (650 m asl) was built from three stages of volcanism (Figure 1.5 [in original text]).\"\r\n\"Three small extrusive domes formed during the last stage of volcanism. One is located on the southeast flank of the shield volcano cone and two are at the summit of the younger cone (Myers and Frost, 1994). Coats (1956) temporally correlated these domes based on topography. The domes can also be correlated in age to the features on which they grew (Myers and Frost, 1994). The summit domes were emplaced after the young cone, and the flank dome was emplaced after the shield building stage but potentially before the summit domes.\"\r\n\"...three domes, one of which has a data of 0.21+/-0.05 Ma.\"\r\nFrom Myers and Frost (1994): \"The last volcanic activity of Mount Adagdak is represented presumably by three, small extrusive domes. Two of these units occupy the younger composite cone’s crater whereas the third occurs on the southeast flank of the older composite cone (Fig. 2 [in original text]). Although Coats (1956) correlated this dome with the summit domes on the basis of topographic form, it could be related temporally to the older composite cone upon which it rests.\"\r\n\"Although similar to the rest of the volcanic suite, the volcanic domes differ from one another geochemically. The flank dome consists of basalts and basaltic andesites (50.8-53.6 wt. % SiO2) with high alumina (~19 wt. %), 9-10% CaO, and less than 1% K2O. In contrast, the summit domes have 59.5 to 62.9 wt. % silica, low Al2O3 (~17 wt. %) and CaO (6.3-6.8%) and are enriched in K2O (1.33-1.53% vs 0.85-0.97%, respectively).\"\r\nFrom Coats (1956): \"Two hornbelde andesite domes occur in the crater of the younger composite cone, and a basalt dome occurs low on the southern flank of the older one. The northern and larger of the two crater domes shows planar banding, which trends roughly parallel to the contact and dips steeply.\"","StartYear":-208050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":50000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Adagdak","ParentVolcano":"Adagdak","VolcanoID":"ak3","ParentVolcanoID":"ak3"},{"ID":2331,"Name":"Espenberg Whitefish Maar","Description":"From Hopkins (1988): \"The youngest and most spectacular volcanic features in the Devil Mountain-Cape Espenberg area consist of a group of five maars (shallow, broad, low-rimmed explosion craters formed by eruptions rich in steam).\"\r\nFrom Beget and others (1996): \"Whitefish Maar lies 15 km west of the Devil Mountain Maar, is 4.3 km in diameter, and covers 15 km2, although the lake basin has been partly filled by alluvium and other sediments since the eruption. Exposures through proximal hydromagmatic deposits are rare at the older maars, but isolated exposures exist in stream gullies at each older maar, and in each case the absence of paleosols, nonvolcanic sediment, or other stratigraphic breaks suggests each of these maars formed as the result of complex but monogenetic eruptive events.\"\r\n\"...Whitefish Maar may be 100-200,000 years old (Hopkins, 1988; Beget and others, 1991).\"","StartYear":-198050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-98050,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Espenberg","ParentVolcano":"Espenberg","VolcanoID":"ak95","ParentVolcanoID":"ak95"},{"ID":2251,"Name":"Drum Sheep Creek Tephra-F","Description":"From Westgate and others (2007): \"‘SCt’ refers to a family of tephra beds that closely resemble one another in their petrographic and compositional characteristics. Its members are named as follows: SCt-F (Fairbanks, Alaska, e.g. UT734), SCt-CC (Canyon Creek, Alaska, e.g. UT250), SCt-C (western Yukon, e.g. UT2096), SCt-K (western Yukon, e.g. UT1052), and SCt-A (western Yukon, e.g. UT1051).\"\r\n\"SCt [Sheep Creek Tephra] is now known to be made up of several stratigraphic units: SCt-F (Fairbanks, Alaska; 200 ka), SCt-CC (Canyon Creek, Alaska), and in the western Yukon, SCt-C, SCt-K (80 ka), and SCt-A...Compositional and temporal controls, including Sr isotopes, suggest Mount Drum in the Wrangell volcanic field as the source of the SCt beds.\"\r\n\"Sheep Creek-F tephra erupted from a vent in the WVF about 190 ka with fallout directed to the northwest across the Fairbanks region of central Alaska. Mount Drum is the most likely source because of strong compositional similarities with Mount Drum pumice, close Sr isotope values, and the fact that Mount Drum experienced a catastrophic eruption sometime after 240 k.\"\r\n\"SCt takes its name from an occurrence in the east wall of the Sheep Creek Cut mining exposure, about 15km north-west of Fairbanks, Alaska (Fig. 2, locality 8 [in original text]; Table 1 [in original text], [sample] UT734). It was initially sampled by T.L. Pewe in 1956 and sent to Westgate in 1971, when it was determined to be chemically and petrographically distinct from other tephra beds then known in the Fairbanks region. At this site, SCt occurs as a 2- to 3-cm-thick white layer 1.5 m below the contact of Gold Hill Loess (GHL) and the overlying retransported loess of the late Pleistocene Goldstream Formation (Preece and others, 1999). The GHL is 20m thick here and overlies the Cripple Gravel of late Tertiary age. The Upper Eva Creek site (Fig. 2, locality 6 [in original text]; [sample] UT746) is important because of the association of SCt with Old Crow tephra ([sample] UT744), and the Dome Ash Bed ([sample] UT745). At this site, SCt has a maximum thickness of 6 cm and has been deformed into a solifluction fold within the GHL. Old Crow tephra and the Dome Ash Bed are 3 and 4.5 m above SCt, respectively. Additional SCt sample sites in the Fairbanks area are shown in Fig. 2 [in original text] and listed in Table 1 [in original text].\"\r\n\"SCt is a white bed with abundant mafic minerals. It has a maximum thickness of 6 cm and a characteristic tripartite stratigraphy in the Fairbanks area: namely, a lowermost sandy layer with abundant mafic crystals, a finer-grained vitric unit, and a capping layer of crystal-rich reworked tephra. The major mineral species are hornblende, plagioclase showing disequilibrium features, such as embayed cores that were later overgrown, and lesser amounts of ilmenite, magnetite, a strongly pleochroic hypersthene, and trace quantities of basaltic hornblende, quartz, apatite, and augite. The glass consists of frothy, highly vesicular pumice fragments with numerous microphenocrysts. It has a calc-alkaline rhyolitic composition (Table 2 [in original text]), although a few shards are dacitic. Equivalence of all SCt samples in the Fairbanks area is supported by the coherent, tight glass compositional trends seen in Fig. 3 [in original text].\"\r\n\"Stratigraphic evidence at the Upper Eva site demonstrates that SCt is older than Old Crow tephra, which has a glass-ITPFT age of 140 710 ka (Preece and others, 1999)-an age supported by loess thermoluminescence (TL) ages (Berger and others, 1996). The minimum and maximum probable TL ages for SCt are 178+/-725 and 205+/-731 ka, giving a probable age for SCt in the Fairbanks area of 190+/-720 ka (Berger and others, 1996).\"","StartYear":-188050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Drum","ParentVolcano":"Drum","VolcanoID":"ak81","ParentVolcanoID":"ak81"},{"ID":2271,"Name":"Drum Sheep Creek Tephra-CC","Description":"From Westgate and others (2007): \"‘SCt’ refers to a family of tephra beds that closely resemble one another in their petrographic and compositional characteristics. Its members are named as follows: SCt-F (Fairbanks, Alaska, e.g. UT734), SCt-CC (Canyon Creek, Alaska, e.g. UT250), SCt-C (western Yukon, e.g. UT2096), SCt-K (western Yukon, e.g. UT1052), and SCt-A (western Yukon, e.g. UT1051).\"\r\n\"Sheep Creek-CC tephra is known from one site, Canyon Creek (Fig. 1, locality 1 [in original text]).\"\r\n\"SCt [Sheep Creek Tephra] is now known to be made up of several stratigraphic units: SCt-F (Fairbanks, Alaska; 200 ka), SCt-CC (Canyon Creek, Alaska), and in the western Yukon, SCt-C, SCt-K (80 ka), and SCt-A...Compositional and temporal controls, including Sr isotopes, suggest Mount Drum in the Wrangell volcanic field as the source of the SCt beds.\"\r\n\"Unit 5 [at the Canyon Creek exposure] is the key stratigraphic unit-because it contains angular fragments of tephra believed to have been ‘‘eroded, transported, and redeposited in a frozen state’’ (Weber and others, 1981). This tephra is SCt, here named SCt-CC (Fig. 5 [in original text]). In their 1981 paper, Weber and others stated that this tephra was identified by Westgate as the Dome Ash Bed, but further work showed this identification to be incorrect. Close scrutiny of Fig. 5 [in original text] suggests another interpretation of the relationship of SCt-CC to the gray sands-namely, that the tephra and sands were once a coherent sedimentary sequence, which later was remobilized, at which time both the tephra and sands were deformed. The tephra pods show plastic deformation in places, and elsewhere are preserved as thin beds up to 10 cm long that are parallel to bedding. The gray sands show very variable bedding attitudes. The deformational mechanism is likely downslope movement (solifluction) during the periglacial conditions that prevailed following emplacement of the sands and tephra. This interpretation would mean that the tephra and sands are penecontemporaneous-a very different interpretation to the ‘‘re- worked tephra’’ idea. Indeed, if the tephra was eroded from the upstream river bank and incorporated into the gray fluvial sands as frozen pieces, presumably some of those pieces would contain remnants of the original host sediment. None is seen in the field (see photograph in Fig. 5 [in original text]). Hamilton and Bischoff (1984) noted this point and concluded that the tephra clasts were probably eroded from a recent surface accumulation, in which case, the tephra would be approximately contemporaneous with the alluvium of unit 5. Hopefully, future field studies will be able to resolve this problem of the temporal relationship between the tephra and its host alluvium.\"\r\n\"The mineral assemblage of SCt-CC is similar to SCt in the Fairbanks area. A strongly pleochroic hypersthene with fluid and opaque inclusions is abundant as are hornblende and plagioclase. Ilmenite and magnetite are conspicuous and trace amounts of basaltic hornblende, augite, and quartz are present. Many of the minerals do not have attached glass and are slightly rounded, but otherwise look the same as those with attached glass. A white frothy pumice is the dominant phase, and occurs together with a small amount of brown glass that is not observed in SCt in the Fairbanks area. The pumiceous glass has a rhyolitic composition but is very different from the glass in the SCt occurrences at Fairbanks; SiO2 and K2O are higher and TiO2, Al2O3, FeOt, CaO, and Na2O are lower (Table 2 [in original text]). The broadly similar petrographic features and a co-linear relationship with SCt on the K2O-SiO2 plot (Fig. 6 [in original text]) led to the view, albeit unpublished, that SCt-CC was co-magmatic with SCt, but, being more evolved, was likely slightly older-the more silicic cap of the magma body being tapped first.\"\r\n\"Bones beneath SCt-CC and near the base of unit 5 have a 14C age of 39,360+/-1740 B.P. (Weber and others, 1981) and a U-series age of about 80 ka (Hamilton and Bischoff, 1984). These discrepant age estimates both severely underestimate the 190 ka age suggested by the tephra correlation noted above. Bison bones are present in this fossil assemblage and point to a Rancholabrean land mammal age-in other words, SCt-CC is probably of MIS 6 age or younger.\"","StartYear":-188050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-37410,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Drum","ParentVolcano":"Drum","VolcanoID":"ak81","ParentVolcanoID":"ak81"},{"ID":3871,"Name":"Westdahl pre-glacial flows","Description":"From Wood and Kienle (1990): \"A thick sequence of pre-glacial basalt lava flows comprises most of Westdahl volcano. Many of these lavas are too young to date by the whole-rock K-Ar method, but the lowest flow in one section yielded an age of 0.18 Ma.\"","StartYear":-178050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Westdahl","ParentVolcano":"Westdahl","VolcanoID":"ak322","ParentVolcanoID":"ak322"},{"ID":3521,"Name":"St. Paul Island Cone Hill Complex","Description":"From Winer and others (2004): \"The Cone Hill complex is composed of numerous lava flows erupted from a northeast-southwest trending zone of volcanic vents and related features along Cone Hill ridge. Fig. 9 [in original text] summarizes the main features of the complex. An important point not evident in Fig. 9 is that the extreme southwest end of the ridge is smoother and more vegetated than the higher and presumably younger central region and northeast end. A thin lava flow erupted from a spatter cone along the central part of the Cone Hill ridge yields an 40Ar/39Ar age of 120+/-40 ka (SP98-58) and a lava flow from the northeast end of the ridge yields an 40Ar/39Ar age of 180+/-40 ka (SP98-46).\"\r\n\"The diversity of volcanic features on the Cone Hill ridge suggests that the complex formed by a variety of volcanic processes operating over a substantial period of time. Eruptive activity likely began with a fissure eruption when dikes intercepted the surface, and subsequently localized to several points. Explosive tephra-forming eruptions were followed by, and perhaps accompanied by, effusive outpourings of pahoehoe that flowed to both sides of the fissure, thereby forming a topographic ridge. Vents were established with reused conduits, especially at the ends of the ridge where calderas that truncate older pyroclastic cones are located. During periods of sustained effusion of low-viscosity lava, growing pahoehoe fields were fed by lava tube breakouts along Cone Hill ridge. Some of the tubes are now exposed by roof collapse. The presence of feeder dikes and pit craters and the development of northeast striking fissures (ground cracks with little vertical offset) and faults along the ridge are evidence that extension accompanied, and possibly post-dated, eruptions along the Cone Hill ridge.\"","StartYear":-178050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":40000,"StartQualifierUnit":"Years","EndYear":-118050,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":40000,"EndQualifierUnit":"Years","Volcano":"St. Paul Island","ParentVolcano":"St. Paul Island","VolcanoID":"ak264","ParentVolcanoID":"ak264"},{"ID":3241,"Name":"Ugashik-Peulik 171000 yBP","Description":"From Miller (2004): \"The only isotopically-dated volcanic rocks are dacite from the south rim of the caldera which yielded a single whole-rock K-Ar age determination of 171,000+/-22,000 yrs (table 2 on plate 2 [in original text]).\"","StartYear":-169050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":22000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Ugashik-Peulik","ParentVolcano":"Ugashik-Peulik","VolcanoID":"ak295","ParentVolcanoID":"ak295"},{"ID":3291,"Name":"Trident Northeast-Ridge Dacite","Description":"From Hildreth and others (2003): \"The northeast-ridge dacite, which is stratigraphically high in the pile and extends nearly to the summit (peak 6010), yields a K-Ar age of 142+/-15 ka.\"\r\n\"For East Trident, a near-basal andesitic lava flow resting on oxidized breccia at glacier level on the nose of the north-west prong (which separates Glaciers 1 and 2, fig. 3 [in original text]) yields a weighted mean age of 143+/-8 ka, analytically indistinguishable from an age of 142+/-15 ka on a 100-m-thick dacitic lava flow that caps part of the northeast ridge of the edifice. These samples appear to bracket most of the dozens of lava flows that make up the edifice, suggesting that eruptive activity at the small East Trident cone was short lived. The ages indicate not only that East Trident is the oldest member of the Trident group but also that it predates the oldest recognized eruptive products of neighboring Katmai and Mageik Volcanoes (Hildreth and Fierstein, 2000; Hildreth and others, 2000).\"","StartYear":-140050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":15000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Trident","ParentVolcano":"Trident","VolcanoID":"ak288","ParentVolcanoID":"ak288"},{"ID":1571,"Name":"Cone 3601","Description":"From Hildreth and others (2004): \"It [Cone 3601] consists of blocky and columnar lavas (132+/-27 ka), breccia sheets, and stratified scoria. Products contain opx, magnetite, and abundant small plagioclase phenocrysts.\"","StartYear":-130050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":27000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cone 3601","ParentVolcano":"Cone 3601","VolcanoID":"ak55","ParentVolcanoID":"ak55"},{"ID":1651,"Name":"Emmons Intracaldera activity","Description":"From Waythomas and others (2006): \"At least two distinct episodes of intra-caldera andesitic volcanism have been documented at the Emmons Lake volcanic center. During the first episode, at least four andesitic lava flows were erupted between the Volcano Bay and Boundary calderas in the southernmost part of the caldera complex (unit ol, fig.8 [in original text]) about 126,000 years B.P.\"","StartYear":-124050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Emmons Lake Caldera","ParentVolcano":"Emmons Lake Volcanic Center","VolcanoID":"ak92","ParentVolcanoID":"ak93"},{"ID":4371,"Name":"Little Sitkin CFE I","Description":"From Miller and others (1998): \"The active stratovolcano on Little Sitkin Island occurs within the eroded remnants of a nested double caldera of probable late Pleistocene age. The older caldera (Caldera One) is about 4.8 km in diameter and is centered slightly northeast of the island's midpoint. The caldera formed at the site of a large stratovolcano, the remnants of which are the oldest rocks exposed on the island (unit Qtw).\"","StartYear":-124050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-9750,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Little Sitkin","ParentVolcano":"Little Sitkin","VolcanoID":"ak182","ParentVolcanoID":"ak182"},{"ID":1671,"Name":"Emmons Gap Welded Tuff","Description":"From Waythomas and others (2006): \"Major Plinian/ultra-Plinian eruption. Extensive ignimbrite sheets.\"\r\n\"Major explosive events with high column of ash and pyroclastic debris. Extensive ash dispersal and formation of mobile and far traveling pyroclastic flows.\"\r\n\"Eruptive product studies associated with caldera formation date the major eruptions around 294,000, 234,000, 123,000, 100,000, 30-50,000, and 26,000 years ago. Each of these eruptions produced relatively extensive pyroclastic-flow deposits of dacite to rhyolite composition hot enough to weld when deposited and form the welded tuff units shown in figures 7 and 8 [in original text]. Some of the welded tuffs show evidence of secondary flowage (rheomorphic tuffs) as far as 35 km from their source calderas (fig.8 [in original text]). Rheomorphic welded tuffs are unique to the Emmons Lake volcanic center and are found nowhere else in the Aleutian arc. The welded tuffs crop out in areas southeast and northeast of the caldera complex where they flowed into and filled preexisting valleys and ancestral drainages.\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2017) reports a magnitude of 4, bulk eruptive volume of 0.10 cubic km and a dense rock equivalent eruptive volume of 0.040 cubic km for the eruption.","StartYear":-121050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Emmons Lake Caldera","ParentVolcano":"Emmons Lake Volcanic Center","VolcanoID":"ak92","ParentVolcanoID":"ak93"},{"ID":1531,"Name":"Mt Churchill Dacite Flow","Description":"From Richter and others (1995): \"The exception to the tephra occurrences along the south-east ridge [of Mount Churchill summit area] is an outcrop of flow-banded dacite ([sample number] 90ADg-3) that underlies the tephra. The dacite is a pyroxene-bearing, hornblende dacite, mineralogically distinct from the tephra (see modes, Table 1 [in original text]). Plagioclase from the dacite yielded a K/Ar age of 119 +/- 17 ka (N. Shew, written communication, 1991), indicating that Mount Churchill has been active at least since the Late Pleistocene.\"","StartYear":-117050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":17000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Churchill, Mt","ParentVolcano":"Churchill, Mt","VolcanoID":"ak50","ParentVolcanoID":"ak50"},{"ID":3301,"Name":"Trident Mount Cerebus Dome","Description":"From Hildreth and others (2003): \"Adjacent Mount Cerberus, a compositionally similar dacite dome (fig. 9 [in original text]), yields a less precise age of 114+/-46 ka, which (in view of the respective analytical errors) need not differ significantly from that of falling mountain.\"\r\n\"The two largest domes (fig. 9 [in original text]), 425-m-high Falling Mountain and 365-m-high Mount Cerberus (each 0.3-0.4-km cubed volume), are compositionally similar to the smaller (unnamed) domes, which range in volume from 0.015 to 0.12 km3. Like West Trident, all the domes contain chilled enclaves (1-15-cm diam) of phenocryst-poor andesite (54-58 weight percent SiO2), although such enclaves are uncommon in the dacite of Mount Cerberus. All the domes are glacially scoured, and several are severely eroded. Mount Cerberus and Falling Mountain, however, are stout domes that are morphologically little modified by ice and were suspected of being very young (Hildreth, 1983, 1987). Repeated search has nonetheless turned up few remnants of glassy carapace, and K-Ar data now give late Pleistocene ages for both domes-Falling Mountain 70+/-8 ka and Mount Cerberus 114+/-46 ka. The superficiality of glacial erosion may reflect their compact profiles and positions close to the Alaska Peninsula drainage divide. Flanking the entrance to Katmai Pass at the northwest foot of West Trident (fig. 9 [in original text]), both domes (63-65 weight percent SiO2) have a compositional affinity (low K, Zr) with the Trident group.\"","StartYear":-112050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":46000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Trident","ParentVolcano":"Trident","VolcanoID":"ak288","ParentVolcanoID":"ak288"},{"ID":1681,"Name":"Emmons Intracaldera Activity","Description":"From Waythomas and others (2006): \"Lava domes, welded tuff. Large Plinian eruption.\"\r\n\"Major explosive events with high column of ash and pyroclastic debris. Extensive ash dispersal and formation of mobile and far traveling pyroclastic flows.\"\r\n\"Eruptive product studies associated with caldera formation date the major eruptions around 294,000, 234,000, 123,000, 100,000, 30-50,000, and 26,000 years ago. Each of these eruptions produced relatively extensive pyroclastic-flow deposits of dacite to rhyolite composition hot enough to weld when deposited and form the welded tuff units shown in figures 7 and 8 [in original text]. Some of the welded tuffs show evidence of secondary flowage (rheomorphic tuffs) as far as 35 km from their source calderas (fig.8 [in original text]). Rheomorphic welded tuffs are unique to the Emmons Lake volcanic center and are found nowhere else in the Aleutian arc. The welded tuffs crop out in areas southeast and northeast of the caldera complex where they flowed into and filled preexisting valleys and ancestral drainages.\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2017) reports a magnitude of 4, bulk eruptive volume of 0.10 cubic km and a dense rock equivalent eruptive volume of 0.040 cubic km for the eruption.","StartYear":-98050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Emmons Lake Caldera","ParentVolcano":"Emmons Lake Volcanic Center","VolcanoID":"ak92","ParentVolcanoID":"ak93"},{"ID":3351,"Name":"Trader Mtn 98000 yBP","Description":"Trader Mountain is a small dacitic stratocone-like feature with an extrusive dome; lava flows dip away from the center in all directions (Chris Nye, oral commun., 2007). Wilson and others (1995) [1] alternatively describe Trader Mountain as a hypabyssal dacite plug, and report a \"potassium-argon age of 0.98+/- 0.05 Ma (F.H. Wilson and Nora Shew, unpub. data, 1988).\"","StartYear":-96050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":50000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Trader Mtn","ParentVolcano":"Trader Mtn","VolcanoID":"ak287","ParentVolcanoID":"ak287"},{"ID":2511,"Name":"Iron Trig cone 88000 yBP","Description":"From Hildreth and others (2004): \"(Peak 4260) is a mafic scoria cone (53-54% SiO2) atop the basement divide between the Savonoski and Kamishak Rivers, 50 km NE of Mount Katmai and 25 km north of Mount Denison (Fig. 2 [in original text]). The glaciated cone (Fig. 2 [in original text]), 800 m across with 250 m relief, consists of stratified scoria, agglutinate, and thin lava sheets that are cut by a small intrusion exposed on the west face. Ejecta and lava contain phenocrysts of plagioclase, olivine, cpx, and magnetite. A lava-flow apron (88+/-27 ka) descends the WSW flank to an elevation 300 m lower than the cone, condensing into a single flow 20 m thick at its eroded terminus, 2 km from the cone.\"","StartYear":-86050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":27000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iron Trig cone","ParentVolcano":"Iron Trig cone","VolcanoID":"ak134","ParentVolcanoID":"ak134"},{"ID":3211,"Name":"Wrangell 80000 yBP","Description":"From Richter and others (1990): \"One of the youngest reliably identified Mount Wrangell lavas - a flow high on the southwest flank of the shield - has yielded a K-Ar age of 0.08 Ma ([sample] no. 2; Nye 1983).\"","StartYear":-78050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Wrangell","ParentVolcano":"Wrangell","VolcanoID":"ak326","ParentVolcanoID":"ak326"},{"ID":2261,"Name":"Drum Sheep Creek Tephra-C, K, A","Description":"From Westgate and others (2007): \"‘SCt’ refers to a family of tephra beds that closely resemble one another in their petrographic and compositional characteristics. Its members are named as follows: SCt-F (Fairbanks, Alaska, e.g. UT734), SCt-CC (Canyon Creek, Alaska, e.g. UT250), SCt-C (western Yukon, e.g. UT2096), SCt-K (western Yukon, e.g. UT1052), and SCt-A (western Yukon, e.g. UT1051).\"\r\n\"Sheep Creek-K tephra is widely distributed across the Klondike goldfields (Fig. 7, Table 1 [in original text]), and is present at Lost Chicken, Alaska, Soya Pup, Thistle Creek, and Stewart River localities, Yukon (Figs. 1 and 8 [in original text]). Sheep Creek-C tephra occurs at Dominion Creek (Fig. 7, locality 16 [in original text]), where it is found on the surface of a forest bed, exactly the same stratigraphic setting as at Ash Bend site (Fig. 8, locality 21, UT2096). SCt-A (Ash Bend tephra) is also at Ash Bend, Yukon.\"\r\n\"SCt [Sheep Creek Tephra] is now known to be made up of several stratigraphic units: SCt-F (Fairbanks, Alaska; 200 ka), SCt-CC (Canyon Creek, Alaska), and in the western Yukon, SCt-C, SCt-K (80 ka), and SCt-A. Beds C, K, and A must be similar in age because of their close stratigraphic association at Ash Bend in Yukon. Compositional and temporal controls, including Sr isotopes, suggest Mount Drum in the Wrangell volcanic field as the source of the SCt beds.\"\r\n\"Assuming Mount Drum is the source of the younger SCt beds, renewed volcanic activity must have started prior to 80 ka, the age of SCt-K, and probably as early as 100 ka, given the palaeoenvironmental setting of the older SCt-C bed at Ash Bend-namely, boreal forest conditions of the last interglacial (Schweger, 2003 ). During this later phase of activity, tephra fallout was directed to the northeast across easternmost Alaska and western Yukon.\"\r\n\"The presence of glass shards of SCt-C composition in SCt-K samples and glass shards of SCt-K composition in the SCt-A sample suggest these beds come from the same volcano. Systematic differences between these three tephra beds also suggest a close genetic relationship.\"\r\n\"Occurrences of SCt in Yukon are presently restricted to the western Yukon, specifically, the Klondike district near Dawson City, Thistle Creek, Soya Pup, and the lower stretch of the Stewart River (Figs. 1, 7, 8, and Table 1 [in original text]). The most important section is on the Stewart River at Ash Bend (Fig. 8, locality 21 [in original text]) where SCt is found in association with two other tephra beds (Fig. 9 [in original text]). All three tephra beds occur within the sedimentary fill of a channel cut into the Reid glacial drift (Westgate and others, 2001). The exposure in 1999 showed the basal channel-fill sediments to consist of organic-rich silts (unit 4 [in original text]) with transported spruce logs and vertebrate fossils. SCt ([sample] UT1052) occurs in the overlying silts (unit 5 [in original text]), which contain less organic material, and the very thin Ash Bend tephra ([sample] UT1051) occurs in the lower part of unit 6-90 cm above SCt-in a coarsening-upward sequence of largely inorganic silt and sand (Fig. 9 [in original text]). Major slumping at the downstream end of the Ash Bend site in 2005 revealed a thicker channel-fill sequence including SCt with a new tephra bed ([sample] UT2096) 6.5 m below within the organic-rich sediments (Fig. 9B [in original text]).\"\r\n\"SCt ([sample] UT1052) at Ash Bend contains a white, frothy pumice similar to that of the Fairbanks occurrences with the exception that trace amounts of a low vesicular glass and bubble-wall shards are present. The mineral assemblage likewise resembles SCt at Fairbanks being dominated by plagioclase and hornblende with lesser amounts of ilmenite and magnetite. Hypersthene is scarce and slightly- to non-pleochroic-that is, different from the variety in SCt at Fairbanks and Canyon Creek. Apatite, clinopyroxene and quartz occur in trace quantities. The glass composition of SCt at Ash Bend falls within the envelope on the K2O-SiO2 plot defined by SCt samples from Fairbanks and Yukon (Fig. 6 [in original text]). The petrographic features of Ash Bend tephra ([sample] UT1051) closely resemble those of the SCt bed from the same site. However, its glass is distinctly less silicic (Fig. 6, Table 2 [in original text]).\"","StartYear":-78050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Drum","ParentVolcano":"Drum","VolcanoID":"ak81","ParentVolcanoID":"ak81"},{"ID":3501,"Name":"St. Paul Island 80000 yBP","Description":"From Winer and others (2004): \"Hutchinson Hill is a low profile shield volcano (elevation 30 m) located on Northeast Point (Fig. 2 [in original text]). The vent area is constructed of scoria and welded spatter covered by dozens of thin (\u003c1 m) layers of basaltic lava flows that dip gently away from the summit. Surrounding the vent region is a low-lying shield of no more than three compound lava flows each less than 2 m thick. The stratigraphically highest lava flow at the summit of the cone yields an 40Ar/39Ar age of 80+/-50 ka.\"\r\n\"Our interpretation of Hutchinson Hill is that it began as a scoria cone built by gas-rich, explosive eruptions. As the erupting magma became depleted in volatiles, explosivity waned and thin, spatter-fed clastogenic lava flows cascaded down the gentle slopes of the cone, followed by effusive outpouring of largely degassed lava. Overall, eruptive activity at Hutchinson Hill was much less explosive than at the other monogenetic centers, and may represent an analog to activity that formed the platform lavas, but on a more limited scale.\"","StartYear":-78050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":50000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"St. Paul Island","ParentVolcano":"St. Paul Island","VolcanoID":"ak264","ParentVolcanoID":"ak264"},{"ID":3311,"Name":"Trident 73000 yBP","Description":"From Hildreth and others (2003): \"On its southwest side, the summit dacite rests on a coherent andesitic lava flow (61.7 weight percent SiO2) that yields a K-Ar age of 73+/-12 ka. The northwest ridge of the edifice consists mostly of a glaciated stack of thinner lava flows and breccias, but low on steep northern spurs of the ridge are two massive andesitic lavas (60 weight percent SiO2), each 100 to 200 m thick, which are probably glacially truncated coulees but, alternatively, might be older domes.\"\r\n\"An andesitic lava flow that directly underlies the summit dome of Trident I, about 100 m southwest of peak 6115, yields an age of 73+/-12 ka. Most of the edifice appears to lie stratigraphically beneath this lava, except for the mafic pyroclastic assemblage (unit tca, fig. 3 [in original text]), which apparently drapes many of the andesites and yields a 40Ar/39Ar age of 58+/-15 ka (Hildreth and others, 2003). Because much of the Trident I pile is banked against its eastern neighbor (dated at 143+/-8 ka), the active lifetime of Trident I appears to be reasonably well bracketed.\"","StartYear":-71050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":12000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Trident","ParentVolcano":"Trident","VolcanoID":"ak288","ParentVolcanoID":"ak288"},{"ID":2521,"Name":"Iskut-Unuk River cones 70000 yBP","Description":"From Hauksdottir and others (1994): \"Flows at the base of the Iskut River Lava Flats are about 70,000 years old, based on K-Ar dating...\"","StartYear":-68050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iskut-Unuk volcanic field","ParentVolcano":"Iskut-Unuk volcanic field","VolcanoID":"ak136","ParentVolcanoID":"ak136"},{"ID":3321,"Name":"Trident Falling Mountain Dome","Description":"From Hildreth and others (2003): \"Falling Mountain dacite dome, the northeast face of which was sheared off (fig. 2 [in original text]) during the 1912 eruption at adjacent Novarupta, yields an age of 70+/-8 ka.\"\r\n\"The two largest domes (fig. 9 [in original text]), 425-m-high Falling Mountain and 365-m-high Mount Cerberus (each 0.3-0.4-km cubed volume), are compositionally similar to the smaller (unnamed) domes, which range in volume from 0.015 to 0.12 km3. Like West Trident, all the domes contain chilled enclaves (1-15-cm diam) of phenocryst-poor andesite (54-58 weight percent SiO2), although such enclaves are uncommon in the dacite of Mount Cerberus. All the domes are glacially scoured, and several are severely eroded. Mount Cerberus and Falling Mountain, however, are stout domes that are morphologically little modified by ice and were suspected of being very young (Hildreth, 1983, 1987). Repeated search has nonetheless turned up few remnants of glassy carapace, and K-Ar data now give late Pleistocene ages for both domes-Falling Mountain 70+/-8 ka and Mount Cerberus 114+/-46 ka. The superficiality of glacial erosion may reflect their compact profiles and positions close to the Alaska Peninsula drainage divide. Flanking the entrance to Katmai Pass at the northwest foot of West Trident (fig. 9 [in original text]), both domes (63-65 weight percent SiO2) have a compositional affinity (low K, Zr) with the Trident group.\"","StartYear":-68050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":8000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Trident","ParentVolcano":"Trident","VolcanoID":"ak288","ParentVolcanoID":"ak288"},{"ID":3431,"Name":"Table Top Mtn 68000 yBP","Description":"From McConnell and others (1998): \"The satellite vents [of Makushin Volcano] produced high-volume, individually homogeneous deposits characteristic of monogenetic eruptions. Individual vents and flows are differentiated by location, petrology, and stratigraphy and occur along a zone parallel to the Aleutian Arc trend. None show evidence of activity into historic times and similar erosional features suggest they were all active after the Pleistocene glaciation receded. Samples from all the satellite eruptive centers were analyzed for 40Ar/39Ar ages. Only the dates from Table Top Mountain and Pukushin Cone are statistically different from zero with ages of 68+/-14 ka and 22+/-5 ka respectively (table 2 [in original text]).\"","StartYear":-66050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":14000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Table Top Mtn","ParentVolcano":"Table Top Mtn","VolcanoID":"ak275","ParentVolcanoID":"ak275"},{"ID":4501,"Name":"Okmok SR4 tephra","Description":"From Derkachev and others (2018): \"The ~ 64.5 ka SR4 tephra has a distinct basaltic andesite glass composition and was found in three cores on the Shirshov Ridge (Fig. 1) [in text]. Comparison of our glass data with that of the Alaska Volcano Observatory Geochemical Database of whole rock compositions (Cameron et al. 2014; Nye et al. 2018) shows that SR4 glass compositions are very similar to basaltic andesites of Okmok volcano (Umnak Island, Eastern Aleutians) (Figs. 6 and  7) [in text]. Additional support for this correlation comes from the discovery of a geochemically similar, but significantly younger (~ 12 ka), tephra in core U1343 at the eastern margin of the Aleutian basin, which is closer to Okmok (Fig.1 [in text]; Aoki et al. 2012). Peculiar features of Okmok rocks include predominantly mafic compositions, a common presence of olivine in the mineral assemblages, and relatively low Ba/Nb and La/Nb ratios (Figs. 6 and  7) [in text].\r\nAs the products of the volcano demonstrate similar compositions during its history (Finney et al. 2008; Larsen et al. 2013), it is possible that the ~ 64.5 SR4 tephra was also a product of Okmok. The SR4 tephra forms a visible 4-5-cm-thick layer in three cores on the Shirshov Ridge. If the source of SR4 is Okmok volcano, then only justified isopach of 4 cm is an NW-SE elongated ellipse. This isopach embraces an area of 487,400 km2. Accordingly, the single-isopach approach (Legros 2000) yields a minimum ashfall volume of 72 km3, which corresponds to VEI 6 (Newhall and Self 1982). Adopting a density for basaltic ash of 0.8 g/cm3 (Kutterolf et al. 2008b), and a basalt density of 3.0 g/cm3, we obtain a total tephra mass of 5.8 × 10 4Mt and DRE volume of 19 km3, which corresponds to an eruption magnitude of 6.8 (Pyle 1995; Mason et al. 2004). These are only minimum estimates of the eruption parameters, as only few thickness measurements are available and no proximal deposits are known.\r\nIn the absence of well-documented proximal deposits, detailed reconstruction of possible mechanisms of this large eruption is not possible. The estimated volume of SR4 tephra of 20 km3 DRE is, however, comparable to caldera-forming eruptions of Okmok that occurred over the past 12 ka and produced 30 km3 (Okmok I) and 15 km3 (Okmok II) DRE of basaltic material (Larsen et al. 2007). Both the Okmok I and Okmok II eruptions involved phreatomagmatic components. Larsen et al. (2007) thus concluded that interaction of magma with surface water and ice may trigger catastrophic eruptions of mafic magma at Okmok caldera, in addition to large amount of magmatic volatiles accumulated in magma chamber prior to the eruption. We suggest that the mid-Pleistocene Okmok eruption, which provisionally produced SR4 tephra, had a genesis similar to such recent eruptions. Because this older eruption occurred during the last glaciation, an interaction of voluminous basaltic magma with a thick ice cap in Okmok caldera is a plausible mechanism to facilitate the high explosivity of this eruption (Larsen et al. 2007).\"","StartYear":-64000,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Okmok","ParentVolcano":"Okmok","VolcanoID":"ak206","ParentVolcanoID":"ak206"},{"ID":3331,"Name":"Trident 58000 yBP","Description":"From Hildreth and others (2003): \"...the southwest slope (fig. 7 [in original text]) is made up of steeply dipping (25 to 35 degrees) sheets, 0.1 to 3 m thick, of agglutinated mafic fallout rich in accidental lithic fragments, subordinate thin pyroclastic-flow deposits, and associated avalanche rubble. Derived from the central vent of Trident I, these deposits (unit tca, fig. 3 [in original text]) are generally gray brown to brick red, but parts were altered ocherous yellow or orange brown, probably while still hot. Fresh juvenile scoriae and spatter in these deposits are olivine-rich andesite, the most mafic material (53-55 weight percent SiO2) known to have been erupted from the Trident group. A dense spatter blob from agglutinate on the south slope gave a 40Ar/39Ar plateau age of 58+/-15 ka (Hildreth and others, 2003). The strata also contain abundant accidental clasts of the pyroxene andesite that makes up most of the edifice.\"\r\n\"An andesitic lava flow that directly underlies the summit dome of Trident I, about 100 m southwest of peak 6115, yields an age of 73+/-12 ka. Most of the edifice appears to lie stratigraphically beneath this lava, except for the mafic pyroclastic assemblage (unit tca, fig. 3 [in original text]), which apparently drapes many of the andesites and yields a 40Ar/39Ar age of 58+/-15 ka (Hildreth and others, 2003). Because much of the Trident I pile is banked against its eastern neighbor (dated at 143+/-8 ka), the active lifetime of Trident I appears to be reasonably well bracketed.\"","StartYear":-56050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":15000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Trident","ParentVolcano":"Trident","VolcanoID":"ak288","ParentVolcanoID":"ak288"},{"ID":3541,"Name":"Makushin Lava Ramp","Description":"From Bean (1999): \"The feature to the east of Makushin known as the \"Lava Ramp\" consists of a massive andesite lava flow which fills a small portion of upper Makushin Valley and spills over the divide into the upper portions of Driftwood Valley (Fig. 4.14 [in original text]). Total volume is estimated to be 5 km3 (Nye and others 1986). 40Ar/39Ar age dates of \u003c13 ka and \u003c54 ka as well as the presence of glacial striations indicate that it is late Pleistocene in age (McConnell and others, 1997). The \"Lava Ramp\" creates a broad flat divide between Makushin and Driftwood valleys. Tephras are generally well preserved here and are often intercalated with peat layers. Gullies, which form a parallel drainage pattern, provide excellent exposures. Site locations on \"Lava Ramp\" are indicated on Fig. 4.12 [in original text].\"\r\nFrom McConnell and others (1998): \"Approximately 5 km3 (Nye and others, 1986) of massive andesite lava flows which fill the glacially carved Driftwood Valley. The upper reaches of the Lava Ramp flows are obscured by a glacier, but it is believed that the flows were erupted from a flank vent on the eastern side of Makushin volcano (Nye and others, 1984). The andesite are porphyritic containing 30 vol.% plagioclase, 5 vol.% clinopyroxene, 2 vol.% reversely zoned orthopyroxene and minor amounts of normally zoned olivine and opaques in a brown, microlitic groundmass. Flows exposed in upper Makushin Valley exhibit contorted columnar jointing suggestive of contact with glacial ice. At least some fraction of Makushin Valley was still choked with ice at the time of eruption, blocking the flow from inundating that valley. The surface of the Lava Ramp flow has been modified by glacial scouring. 40Ar/39Ar age determinations from two samples yielded poorly constrained ages of late Pleistocene (table 2 [in original text]).\"","StartYear":-52050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":1691,"Name":"Emmons Welded Tuff","Description":"From Waythomas and others (2006): \"Large Plinian eruption.\"\r\n\"Major explosive events with high column of ash and pyroclastic debris. Extensive ash dispersal and formation of mobile and far traveling pyroclastic flows.\"\r\n\"Eruptive product studies associated with caldera formation date the major eruptions around 294,000, 234,000, 123,000, 100,000, 30-50,000, and 26,000 years ago. Each of these eruptions produced relatively extensive pyroclastic-flow deposits of dacite to rhyolite composition hot enough to weld when deposited and form the welded tuff units shown in figures 7 and 8 [in original text]. Some of the welded tuffs show evidence of secondary flowage (rheomorphic tuffs) as far as 35 km from their source calderas (fig.8 [in original text]). Rheomorphic welded tuffs are unique to the Emmons Lake volcanic center and are found nowhere else in the Aleutian arc. The welded tuffs crop out in areas southeast and northeast of the caldera complex where they flowed into and filled preexisting valleys and ancestral drainages.\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2017) reports a magnitude of 4, bulk eruptive volume of 0.10 cubic km and a dense rock equivalent eruptive volume of 0.040 cubic km for the eruption.","StartYear":-48050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-28050,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Emmons Lake Caldera","ParentVolcano":"Emmons Lake Volcanic Center","VolcanoID":"ak92","ParentVolcanoID":"ak93"},{"ID":3201,"Name":"Wrangell Mount Zanetti","Description":"From Miller and others (1998): \"Mt. Zanetti (3965 m) a large (350 m high) steep-sided, relatively undissected cinder-spatter cone occurs high on the northwest flank of the shield and may be the source of some lava flows. Lavas on the southwest flank have flowed as much as 59 km from their source despite being phenocryst-rich andesite, a mobility attributed to a very high eruptions rate (Nye, 1983).\"\r\nRichter and others (1995) state: \"On the basis of radiometric dating K-Ar dating, the lava flows most recently erupted from Mount Wrangell may be 50,000 to 100,000 years old...the one of Mount Zanetti and a few flows on the south flank of Mount Wrangell are probably the youngest products of the volcano. Mount Zanetti probably erupted during the waning stage of the latest major glaciation, possibly less than 25,000 years ago, and a large, young andesite flow that originated in the summit area and traveled more than 40 m (64 km) south and west in the ancestral Copper River Basin may only be 50,000 years old.\"\r\nFrom Richter and others (1990): \"K-Ar ages of 0.05 and 0.06 Ma ([sample] no. 1) were determined on a large and extremely long andesite flow that debouched into the Copper River Basin probably in late Pleistocene time (Yehle and Nichols 1980). These determinations, however, have such large analytical uncertainties that meaningful ages cannot be assigned (JD Obradovich, personal communication 1979).\"","StartYear":-48050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":80000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Wrangell","ParentVolcano":"Wrangell","VolcanoID":"ak326","ParentVolcanoID":"ak326"},{"ID":4011,"Name":"Makushin Koriga Point Flows","Description":"From McConnell and others (1998): \"Flows of older Makushin lavas on the north side of the island form a ragged coastline along Koriga Point and prominent outcrops at Bishop Point. The age of the Koriga Point lavas are 45+/-11 ka (table 2 [in original text]).\"","StartYear":-43050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":11000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":3341,"Name":"Trident 44000 yBP","Description":"From Hildreth and others (2003): \"The K-Ar age of 44+/-12 ka measured for the thick andesitic lava flow that forms the crest of the north ridge (fig. 8 [in original text]) supports our stratigraphic and morphologic inference that West Trident is the youngest of the prehistoric centers in the Trident group.\"\r\n\"For West Trident, which banks against Trident I, a 70-m-thick andesitic lava flow capping the north ridge gave a K-Ar age of 44+/-12 ka. An attempt to date the summit lava of West Trident (fig. 8 [in original text]) failed to yield sufficient radiogenic Ar to provide a meaningful age, supporting our field inference that it is still younger than the dated lava flow.\"","StartYear":-42050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":12000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Trident","ParentVolcano":"Trident","VolcanoID":"ak288","ParentVolcanoID":"ak288"},{"ID":4001,"Name":"Makushin A'a flow","Description":"From McConnell and others (1998): \"Plagioclase-dominant (up to 27 vol.%), two-pyroxene andesitic a’a flow. The end of the flow extends from above Bishop Point Valley to above Koriga Point. Rubbly surface characteristic of a’a flows is still evident at lower elevations. This flow is overlain by the younger Qmbp flows above Bishop Point Valley and Qag above Koriga Point. The matrix is microcrystalline plagioclase and magnetite and the mineralogy also includes minor (\u003c1 vol.%) olivine. Clinopyroxene overgrowths of orthopyroxene are common as are crystal clots of plagioclase and clinopyroxene. 40Ar/39Ar age determinations place its deposition at 40+/-6 ka (table 2 [in original text]).\"","StartYear":-38050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":6000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":2411,"Name":"Hayes River Ignimbrite","Description":"From Wallace and others (2015): \"The basal unit of the Hayes River outcrop is a light gray (N7) to white (N9) pumiceous pyroclastic-flow deposit, the Hayes River ignimbrite (fig. 3 [in original text]). This deposit is 20-30 m thick, and forms the most visually striking part of the Hayes River outcrop (fig. 2 [in original text]). The stratigraphically lowest and largest portion of the Hayes River ignimbrite is a 20-m-thick, lithic-poor (\u003c1 percent) pumiceous, nonwelded pyroclastic-flow deposit (fig. 4A [in original text]). It consists of subangular to subround pumice clasts typically as large as 10 cm (rarely 50 cm) in a fine- to coarse-ash, crystal-rich matrix. The pumice clasts are of two types, (1) dominantly white (N9), friable, biotite-sanidine-plagioclase-quartz rhyolite, with notable foliation caused by alignment of biotite grains, and (2) light gray (N7), finely vesicular rhyolite, less friable than type (1) but with the same mineralogy. Some pumice clasts are texturally banded and are gradational between the two main types. Phenocrysts of feldspar and quartz are as large as 6 mm across. In addition, dense white holocrystalline blocks, also rhyolitic in composition and with the same mineralogy, make up \u003c1 percent of the deposit. The upper 10 m of the Hayes River ignimbrite is lithic-rich, and in some places appears gradational with Unit II.\"\r\n\"The total volume of the Hayes River ignimbrite is not known, as it has been recognized only at the Hayes River outcrop. A minimum estimate of 2 km3 is derived from the total area of the Hayes Glacier drainage upstream (90 km2) and a minimum thickness at the outcrop of 20 m.\"\r\n\"Immediately overlying the Hayes River ignimbrite of Unit I is a thick sequence of complex mass-flowage deposits that are variable in thickness along the 600 m wide outcrop (fig. 2 [in original text]). The relation between Units I and II is unclear, as there is some evidence they may be coeval, but for the sake of clarity we describe these flowage deposits as a separate unit.\"\r\n\"Immediately above the Hayes River ignimbrite in some places is a 2-4 m-thick sequence of laterally discontinuous, coarse diamicton that includes rounded to angular boulders as much as 2 m in diameter, which are composed of mostly intrusive rocks (granite, granodiorite) and some indurated clasts of volcanic breccia (figs. 4B, C [in original text]). No obviously juvenile material was observed in this part of Unit II. The contact between Unit II and the Hayes River ignimbrite below is erosional in some places but graditional in others (figs. 4B, C [in original text]). Where the Hayes River ignimbrite is in direct contact with the overlying diamicton, oxidized gas-escape pipes at the contact and upward into the basal boulder diamicton suggest that the ignimbrite may have been hot when the diamicton was emplaced (fig. 4C [in original text]).\"\r\n\"The upper several meters of Unit II are a poorly sorted, vaguely bedded, matrix-supported, angular-pebble gravel with an oxidized silt-rich upper 25 cm (fig. 4D [in original text]). The dominant clast type in this upper portion of Unit II is rounded dense rhyodacite with prominent quartz and feldspar phenocrysts in a light gray (N7) matrix.\"\r\n\"We have no direct evidence for the eruption age of the Hayes River ignimbrite, however, it must be older than the 4,450+/-30 14C yr B.P. soil beneath Unit III. The limited extent of Hayes River ignimbrite deposits may be the result of erosion by glacial ice. Given the thickness, particle size, and composition of the Hayes River ignimbrite, it likely records a substantial eruption of Hayes Volcano, and we would expect to find correlative tephra deposits in many areas of south-central Alaska if the ignimbrite were emplaced during a Holocene eruption. Radiometric dating of sanidine, zircon, and monazite from the Hayes River ignimbrite’s rhyolite pumice indicate crystallization ages of ~40-30 ka (Calvert, Coombs, and Vazquez, USGS, unpub. data, 2014), thus representing a maximum possible age. Preservation of pre-Holocene pyroclastic deposits in south-central Alaska is extremely limited, presumably due to emplacement on ice or erosion by glacial ice.\"","StartYear":-38050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-2500,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":30,"EndQualifierUnit":"Years","Volcano":"Hayes","ParentVolcano":"Hayes","VolcanoID":"ak116","ParentVolcanoID":"ak116"},{"ID":3531,"Name":"St. Paul Island Bogoslof Hill","Description":"From Winer and others (2004): \"Bogoslof Hill is located at the center of St. Paul Island (Fig. 2 [in original text]). Constructed mostly of pahoehoe lava with small amounts of intercalated scoria, Bogoslof Hill is a low-profile shield with a double summit composed of two cone-shaped vents (Fig. 4C [in original text]) The gently sloping lower flanks (\u003c 8 degrees) of the volcano steepen abruptly to 30 degrees at the summit cones, which are formed almost entirely of welded spatter with minor amounts of scoria. The northwestern cone is a truncated rim of spatter and layered agglutinate surrounding a shallow crater. A lava lake, now solidified, ponded in the crater and partially drained through a breach in the northeastern side of the rim (Fig. 10 [in original text]). The southeastern cone is composed mainly of agglutinate with no exposed crater. In the saddle between the cone-shaped vents is a ~ 30-m-wide crater surrounded by a low spatter rampart (Fig. 10 [in original text]). A small ejecta blanket of scoria overlies a lava flow that issued from the north side of the crater and flowed to the north. This flow yields an 40Ar/39Ar age of 40+/-20 ka (SP98-72). The summit region of Bogoslof Hill volcano is elongate to the east and west and is traversed by numerous subparallel east-west and northeast-southwest striking fissures (Fig. 10 [in original text]). Minor vents and openings to lava tubes are located on the western and southern flanks. The most aerially extensive of all recent lava flows erupted on St. Paul Island extends radially from the Bogoslof Hill vent region and covers approximately 16 km 2 (Fig. 2 [in original text]). The average thickness of the flow is about 4 m with an estimated volume about 0.1 km 3. The basal lobe at the distal extremity of the flow yields an 40Ar/39Ar age of 330F40 ka (SP98-47).\"\r\n\"Eruptions that formed the Bogoslof Hill complex probably began along an east-west striking fissure system. Evidence for this interpretation is the east-west elongation of the vent region and the presence of similarly east-west striking fissures on the flanks (Fig. 10 [in original text]). The eruption localized at the site where the fissures appear to intersect a northeast-trending fault cutting stratigrahically low Bogoslof lavas to the southwest, forming the main edifice (Fig. 2 [in original text]). The vesicularity and patchiness of Bogoslof lavas are interpreted to reflect mingling of compositionally similar magmas at different stages of crystallization in a shallow, subvolcanic magma chamber. In this scenario, magma ascends to high levels, degasses, cools, and crystallizes acicular plagioclase. This is rapidly followed by recharge of another batch of compositionally similar, but volatile-rich, less crystallized magma that triggers an eruption. Patchiness in lavas on the larger scale may be related to breakouts or ephemeral vent formation whereby tube-fed flows are emplaced in a random manner in previously deposited flows. This may be accomplished by exploitation of tubes from previous flows by later erupted lavas, and their emplacement in a chaotic fashion within existing pahoehoe flow fields (Peterson and others, 1994; Calvari and Pinkerton, 1999).\"","StartYear":-38050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":20000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"St. Paul Island","ParentVolcano":"St. Paul Island","VolcanoID":"ak264","ParentVolcanoID":"ak264"},{"ID":2531,"Name":"Iskut-Unuk River cones 33000 yBP","Description":"From Hauksdottir and others (1994): \"Close to Copper King Glacier, near the head of Harrymel Creek, the remnant of a single flow is exposed. It overlies till and itself is overlain by an ablation moraine (B.C. Hydro, 1985). The flow forms a 15-20 m high wall of columnar jointed basalt (e.g., Sta. 18). 14c dating of a sample recovered from the underlying till-basalt contact gives an age of 33,000+/-2000 years (Table 1 [in original text], B.C. Hydro, 1985). The lack of megacrystic feldspar and xenoliths and overall paucity of phenocrysts suggest the lava was erupted from the Cinder Mountain centre.\"","StartYear":-31050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":2000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iskut-Unuk volcanic field","ParentVolcano":"Iskut-Unuk volcanic field","VolcanoID":"ak136","ParentVolcanoID":"ak136"},{"ID":1701,"Name":"Emmons Lake Volcanic Center C2","Description":"From Waythomas and others (2006): \"Major Plinian/ulta-Plinian eruption. Extensive ignimbrite sheets.\"\r\n\"Major explosive events with high column of ash and pyroclastic debris. Extensive ash dispersal and formation of mobile and far traveling pyroclastic flows.\"\r\n\"...the 26,000-year-old event, produced non-welded, highly mobile, pumice-rich pyroclastic flows of rhyolitic composition. The flows crop out over an area of about 3000 km2 surrounding the Emmons Lake volcanic center and up to 60 km from the caldera. A rhyolitic ash fall deposit found 1700 km away in the Klondike region of northwestern Canada has been correlated with the 26,000-year-old event at the Emmons Lake volcanic center (Mangan and others, 2003).\"\r\nFrom Mangan and others (2003): \"The C2 eruption produced a 10 km wide, 12 km long, and \u003e215 m deep caldera in the eastern half of the ELVC (Fig.  3 [in original text]). Rhyolitic pumice flows generated by column collapse extend in all directions from the caldera, covering a minimum area of 2500 km2.  The ignimbrite sheet flowed away from the caldera and terminated beyond the present coastlines of the Pacific Ocean and the Bering Sea more than 60 km away. The C2 deposits exposed in sea cliffs and stream banks on the north side of the caldera overlie fluvial gravel deposits or fill paleovalleys, indicating that the ignimbrite was directed along preexisting drainages (Fig. 5 [in original text]). Most C2 deposits on the north side of the caldera are overlain by glacial deposits associated with the last glacial maximum (LGM) (Waythomas and others 2001). On the northeast side of the caldera, the ignimbrite was channeled through preexisting valleys where it locally ponded and formed thick, massive accumulations of pumice flow that now exhibit near-vertical gas escape structures. On the south side of the caldera, the ignimbrite flowed out over glacier ice and was reworked into lateral moraines composed almost entirely of pumiceous debris (Fig. 5D [in original text]).\"\r\n\"The most revealing outcrop of a C2 pumice flow is a 25 m thick exposure near the Cathedral River valley on the north east side of the caldera (Fig. 6 [in original text]). At this location, the flow has at least eight distinct subunits. Each subunit is \u003c1-10 m thick, clast supported, and massive to faintly bedded.  The subunits are defined by concentrations of angular, pebble-size lithics associated   with concave-up to subhorizontal bounding surfaces.  The median grain size of the subunits ranges from small pebble to very coarse sand-size material (-2.75phi to 0 phi).  Fines in the matrix are characterized by cuspate glass shards and pumice lapilli, with minor lithics and crystals (plagioclase and orthopyroxene with lesser clinopyroxene, and Fe-Ti oxides). The coarse fraction consists of rounded to subrounded pumice clasts a few centimetres to a few decimetres in diameter and smaller, pebble-size, angular to subangular lithics.  The pumice is a frothy rhyolite glass containing a few volume percent plagioclase and orthopyroxene with lesser clinopyroxene, Fe-Ti oxide, small apatite needles, and rare zircon.  The lowest subunit in the sequence contains the largest percentage of lithics, 70 wt.%;  the uppermost subunit has only 15 wt.%.\"\r\n\"Most other outcrops of C2 are massive accumulations of clast-supported pumice, 5-30 m thick.  The deposits are frequently stained pink or orange from high temperature alteration and occasionally contain near-vertical fossil fumaroles. The lithic contents are typically less than 10wt.%,and pumice clasts are subrounded to subangular with diameters of 5-70 cm.\"\r\n\"The most prominent tephra bed in the Klondike district, however, is the Dawson tephra, which was first described by Naeser and others (1982) and later by Preece and others (2000), Westgate and others (2000), and Froese and others (2002) who suggest that the source volcano for Dawson tephra is somewhere in the eastern Aleutian arc. In this paper, we present physical, geochemical, and geochronologic data that identify the Emmons Lake Volcanic Center (ELVC) on the Alaska Peninsula (Fig. 1 [in original text]) as the source of Dawson tephra. The ELVC is located approximately 1700 km southwest of the Klondike localities of Dawson tephra and is the site of one of several caldera-forming eruptions on the Alaska Peninsula that produced extensive pyroclastic fall deposits (Miller and Smith 1987).\"\r\n\"Deposits of Dawson tephra in Yukon Territory are described in Naeser and others (1982), Westgate and others (2000), Preece and others (2000), and Froese and others (2002). The tephra is a fine, light-colored rhyolitic ash (medium silt size, 5.30φ) consisting of 93 wt.% glass and 7 wt.% crystals (plagioclase, orthopyroxene, magnetite, and ilmenite, with trace amounts of clinopyroxene, apatite, and zircon). The tephra consists principally of thin, bubble-wall glass shards. Typical exposures of the tephra show beds of reworked or primary, normally graded tephra 15-30 cm in thickness.\"\r\n\"Deposits of Dawson tephra have been found in at least 20 localities in the placer mining region of the Klondike-Sixtymile area where they are enclosed in loess and muck exposed in mine cuts (Fig. 1 [in original text]).\"\r\n\"We have yet to identify conclusively the specific source vent of the C2 eruption within the ELVC.\"\r\nFrom Davies and others (2016): \"...while Dawson tephra is found commonly in the Yukon, it has rarely been found in the interior of Alaska. Explanations for this have included invoking a more complicated plume trajectory based on satellite data of modern plume movement (e.g. Beget and others, 2004, 2005), or a paucity of late MIS-2 records around the Fairbanks area (e.g. Muhs and others, 2003; Froese and others, 2006). However, recent work has shown that MIS 2 sediments are present, and that Dawson tephra can be found in locations around Fairbanks, but generally as a thin, poorly preserved layer (Jensen and others, 2016). It is also found as a thick deposit in the Gulf of Alaska (Beget and others, 2004; Jensen and others, 2013), supporting Beget’s hypothesis that complicated plume dynamics are a more likely cause for its limited distribution in the central interior of Alaska.\"\r\nFrom Mangan and others (2003): \"For the C2 event, we estimate an eruptive volume of \u003e50 km3 and a column height of 30-40 km (above present sea level). It is thus not surprising that thick, distal ash deposits accumulated in the Yukon Territory about 1700 km beyond the source volcano; however, it is surprising that Dawson tephra has not yet been recognized elsewhere in Alaska. If new deposits of Dawson tephra are discovered, these should assist in correlation of late Quaternary stratigraphic records that delimit the beginning of the last glaciation.\"\r\nFrom Froese and others (2006): \"Dawson tephra erupted in the late winter or spring as evidenced by the interbedding of tephra with thin surface icing horizons, while the bulk of the tephra was mobilized later into the valley bottoms, likely in the same season. The extraordinary thickness of Dawson tephra at sites in the Klondike area thus includes significant reworking of the tephra, with a probable primary thickness of less than 15 cm... Winter deposition of the tephra may have, in part, minimized the terrestrial ecological impacts of the eruption on zonal ‘‘Steppe-tundra’’ vegetation through the retransportation of tephra from hillslopes to the riparian areas, where the tephra became incorporated into local fluvial systems.\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2017) reports a magnitude of 6.7, bulk eruptive volume of 50 cubic km and a dense rock equivalent eruptive volume of 21.28 cubic km for the eruption.","StartYear":-24050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Emmons Lake Caldera","ParentVolcano":"Emmons Lake Volcanic Center","VolcanoID":"ak92","ParentVolcanoID":"ak93"},{"ID":1601,"Name":"Gas Rocks North Point Dome","Description":"From Hildreth and others (2006): \"Separated by a linear trough from the much higher adjacent dome, North Point Dome appears to be an independent extrusion rather than a thick coulee issuing from its neighbor, an inference supported by its slightly more evolved composition (table 1 [in original text]).\"\r\n\"In common with a lava flow associated with North Point Dome (fig. 11 [in original text]), these flows have been truncated and thinned by the ice that flowed northwestward down the lake basin.\"\r\n\"Little or no glassy or pumiceous carapace remains on any of the domes, which were all completely submerged and scoured by glacial ice.\"\r\nHildreth and others (2006) estimate a volume of 0.5 million m cubed for North Point Dome.\r\n\"We [Hildreth and others, 2006] determined two 40Ar/39Ar ages on groundmass concentrates from samples of The Gas Rocks dacite (fig. 9; table 2 [in original text]). Sample U-1, from the small North Point Dome (fig. 3B [in original text]), yielded a weighted-mean plateau age of 25.7+/-1.4 ka, and sample U-2, from Dome 600, 23.3+/-1.2 ka. At their extremes, the two error envelopes just overlap, although nothing on the ground is known to contradict a younger age for the larger dome. Because of their petrographic and compositional similarity, it cannot be excluded that the three domes are essentially contemporaneous, plausibly fed by a common dike, the northwesterly strike of which would be similar to the present-day plate-convergence direction (which might in turn influence the direction of maximum horizontal compression).\"","StartYear":-23750,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":1400,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Gas Rocks, the","ParentVolcano":"Gas Rocks, the","VolcanoID":"ak107","ParentVolcanoID":"ak107"},{"ID":1611,"Name":"Gas Rocks Dome 600","Description":"From Hildreth and others (2006): \"The larger domes, Domes 600 and 700 (figs. 10, 12 [in original text]), have 180 and 210 m relief, respectively, above the lake. Dome 600 appears to be a single simple extrusion, as shown by the steep jointing that flares slightly outward toward the top of its northeast face (fig. 13 [in original text]). Nonetheless, a pair of lava flows, each 10 to 15 m thick, extends to the shoreline from the foot of that face (fig. 13 [in original text]).\"\r\n\"Little or no glassy or pumiceous carapace remains on any of the domes, which were all completely submerged and scoured by glacial ice.\"\r\nHildreth and others (2006) estimate a volume of 15 million m cubed for Dome 600.\r\n\"We [Hildreth and others, 2006] determined two 40Ar/39Ar ages on groundmass concentrates from samples of The Gas Rocks dacite (fig. 9; table 2 [in original text]). Sample U-1, from the small North Point Dome (fig. 3B [in original text]), yielded a weighted-mean plateau age of 25.7+/-1.4 ka, and sample U-2, from Dome 600, 23.3+/-1.2 ka. At their extremes, the two error envelopes just overlap, although nothing on the ground is known to contradict a younger age for the larger dome. Because of their petrographic and compositional similarity, it cannot be excluded that the three domes are essentially contemporaneous, plausibly fed by a common dike, the northwesterly strike of which would be similar to the present-day plate-convergence direction (which might in turn influence the direction of maximum horizontal compression).\"","StartYear":-21350,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":1200,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Gas Rocks, the","ParentVolcano":"Gas Rocks, the","VolcanoID":"ak107","ParentVolcanoID":"ak107"},{"ID":2781,"Name":"Katmai Late Pleistocene Rhyodacite Pumice-Fall and Ignimbrite (LPFI)/Windy Creek Ashflow","Description":"From Stevens (2012): \"Deposits of a pre-1912 rhyolitic ashflow are exposed on the west side of lower Windy Creek valley (Figure 4 [in original text]). Hildreth and others (2003) map correlative ashflow deposits in Mageik Creek that are dated to 19,240+/-70 RC yr B.P. and posit that the plinian eruption generating these deposits might have been greater in magnitude than that of 1912. The source of these deposits is probably Mount Katmai (Hildreth and others 2003).\"\r\nFrom Fierstein (2007): \"Mount Katmai was also the source of two other large explosive events, one ∼23 ka and the other between 12 and 16 ka, the earlier of which was probably larger than that of 1912.\"\r\n\"The largest and most explosive events in the Katmai cluster originated at Mount Katmai within the past 25,000 years: the Plinian rhyodacitic eruption ∼23 ka that inundated proximal valleys with thick ignimbrite and widely dispersed fallout...\"\r\n\"Lithic-rich stratified pumice-fall deposits 7 and 5 m thick along Mageik and Windy Creeks (Fig. 18 [in original text]) are overlain directly by nonwelded ignimbrite at least 75 and 8 m thick, respectively (Hildreth and Fierstein 2003). Lithic and pumice clasts in the fallout are coarse at both locations-as large as 11 cm (lithics) and 14 cm (pumice) in Mageik Creek; pumice clasts to 5 cm in Windy Creek. Pumice clasts in all the emplacement units, mostly white but some medium gray, are nearly unique among products of the Katmai cluster in containing hornblende phenocrysts and in having 72% SiO2; only the most evolved rhyodacite lava on the south rim of Mount Katmai is mineralogically and chemically similar (not identical; Hildreth and Fierstein 2000, 2003). Survival of so few remnants of such thick deposits suggests that emplacement was largely over ice, and the coarse debris flows and thin glacial deposits overlying these pyroclastic remnants suggest a late Pleistocene age. Organic material at the base of the LPFI in Mageik Creek gave an age of 19,240+/-70 14C year B.P., equivalent to a calibrated age of 22.8 ka, which is comparable to the 40Ar/39Ar age (22.5+/-1.6 ka) of the south-rim Katmai lava. The plinian deposit must be very widespread; it probably extends from Kodiak Island to west-central Alaska, but the work has not yet been completed to confirm that. Because the pumice fall is so coarse and thick in Mageik and Windy Creeks (respectively 7-9 km SW and 21 km WNW of the caldera rim) it seems likely that the rhyodacitic eruption was even larger than that of 1912.\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2017) reports a magnitude of 6.000, bulk eruptive volume of 10.000 cubic km and a dense rock equivalent eruptive volume of 4.000 cubic km for the eruption.","StartYear":-20550,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":1600,"StartQualifierUnit":"Years","EndYear":-17290,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":70,"EndQualifierUnit":"Years","Volcano":"Katmai","ParentVolcano":"Katmai","VolcanoID":"ak147","ParentVolcanoID":"ak147"},{"ID":3441,"Name":"Pakushin cone 22000 yBP","Description":"From McConnell and others (1998): \"The satellite vents [of Makushin Volcano] produced high-volume, individually homogeneous deposits characteristic of monogenetic eruptions. Individual vents and flows are differentiated by location, petrology, and stratigraphy and occur along a zone parallel to the Aleutian Arc trend. None show evidence of activity into historic times and similar erosional features suggest they were all active after the Pleistocene glaciation receded. Samples from all the satellite eruptive centers were analyzed for 40Ar/39Ar ages. Only the dates from Table Top Mountain and Pukushin Cone are statistically different from zero with ages of 68+/-14 ka and 22+/-5 ka respectively (table 2 [in original text]).\"\r\n\"The largest of the satellite vents and is composed of distinctive porphyritic basalt to basaltic-andesite volcanic rocks. The deposit consists of an apron of basaltic pyroclastic flows overlain by a platuea of lava flows. The edificie of Pakushin Volcano is constructed of agglutinates and cinders and contains a single, nested cinder cone. Pakushin Cone displays cirque-like erosion on the south side and flows have been glacially scoured. 40Ar/39Ar age determinations place eruption times at approximately 22+/-5 ka. (table 2 [in original text]).\"","StartYear":-20050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":5000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pakushin cone","ParentVolcano":"Makushin","VolcanoID":"ak209","ParentVolcanoID":"ak188"},{"ID":3401,"Name":"Tanaga 19200 yBP","Description":"From Jicha and others (2012): \"The East Tanaga cone is less rugged and lower than Tanaga volcano, reaching 1584 m. Its summit is relatively flat and topped by a shallow, 250-m-wide crater. The cone is composed predominantly of blocky, amphibole-bearing basaltic to andesitic lavas (unit tel; Fig. 3 [in original text]) that extend to the shore on the northern side of the island and fill in a flat-bottomed amphitheater to the south. Most East Tanaga lavas are Holocene in age based on their intact surface morphologies. One lava sample collected from the base of a sea cliff on the northern flank gave a 40Ar/39Ar age of 19.2+/-7.6 ka, indicating that the volcano is at least as old as latest Pleistocene. A young buff-colored, amphibole-bearing lapilli fall deposit, found on or near the surface in several locations on northwestern Tanaga Island, thickens toward East Tanaga’s summit suggesting it originated from there.\"","StartYear":-17250,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":7600,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Tanaga","ParentVolcano":"Tanaga","VolcanoID":"ak280","ParentVolcanoID":"ak280"},{"ID":2361,"Name":"Espenberg Devil Mountain Lakes Maar","Description":"From Hopkins (1988): \"The youngest and most spectacular volcanic features in the Devil Mountain-Cape Espenberg area consist of a group of five maars (shallow, broad, low-rimmed explosion craters formed by eruptions rich in steam).\"\r\n\"The Devil Mountain Lakes are the freshest in appearance and the most tightly dated of the maars; the north lake is the fresher and younger maar. The basin of North Devil Mountain lake has maximum and minimum diameters of 5.1 and 3.3 kilometers. South Devil Mountain Lake is the smallest of the Espenberg maars, having maximum and minimum diameters of 3.4 and 2.2 kilometers.\"\r\nFrom Beget and others (1996): \"...Devil Mountain Maar, which is an irregular composite crater containing North and South Devil Mountain Lakes (Fig. 1 [in original text]). North Devil Mountain Lake (5.1 km in diameter) is partly separated from South Devil Mountain Lake (3.4 km diameter) by a small sand spit.\"\r\n\"Sequences of bedded surge deposits, airfall lapilli beds, massive pyroclastic flows, and explosion breccia can be traced through many fresh exposures in 10-40 m high cliffs around the Devil Mountain Lakes Maar (Fig. 2a, 2b [in original text]). Stratigraphic sections were measured through the volcanic pile at many sites around the lakes, and complex but uninterrupted sequences of plane-bedded and cross-bedded surge deposits, massive explosion breccia, and scoria beds were found. No trace of nonvolcanic sediment or paleosol development was found at any level within the sequence of volcaniclastic sediments (Fig. 2b [in original text]). Similarly, radiocarbon dates from organic material preserved at numerous sites beneath a widespread tephra deposit on the northern Seward Peninsula produced by the eruptions of the Devil Mountain Lakes Maar all indicate an age of about 17 500 years B.P. (Table 1 [in original text]). The existence of only a single tephra deposit at numerous sites around the maar, the similarity of all radiocarbon dates from beneath the tephra deposits, and the absence of significant stratigraphic breaks in either the distal ash or the proximal volcaniclastic sequence indicate the Devil Mountain Lakes Maar formed during one complex eruptive episode about 17 500 years B.P. The crater produced during those eruptions, measured from rim to rim across the maar lake, is 8 km long by 6 km wide, as much as 200 m deep, and covers over 30 km2 (Fig. 1 [in original text]).\"\r\n\"The bottom of the Devil Mountain Lakes Maar is extensively cratered, with at least eight separate depressions visible in the contour data (Fig. 4 [in original text]). These well-defined craters range from 0.1-1 km in diameter and are 50-100 m deep. The underwater craters seem to trend north-south in South Devil Mountain Lake, but east-west in North Devil Mountain Lake, paralleling the ellipitical asymmetry of each lake basin. Similar but partly infilled craters are also visible in depth profiles from the somewhat older Killeak Lakes.\"\r\n\"We interpret the closed depressions on the floors of the Espenberg maars as small explosion craters, as they are similar in size to typical, small hydromagmatic craters observed elsewhere. These craters evidently mark the sites of explosive activity during the eruption; other explosion craters may have formed earlier in the eruption sequence, only to be obliterated or filled in by later eruptions. Although we are unable to find any published bathymetric data from other maars, we speculate that multiple craters may exist on other maar lake floors. Similar groups of coeval explosion craters have recently been documented at sites like Cerro Xalapaxco in central Mexico, where multiple phreatomagmatic eruptions occurred at a site with an especially abundant water supply (Abrams and Siebe, 1994).\"\r\n\"Radiocarbon dates and tephrochronology, together with relative age estimates based on the degree of erosion and sedimentation in the lake basins, indicate that the Devil Mountain Maar is the youngest,  formed  ca.  17 500  years  B.P.  (Table 1 [in original text])...\"","StartYear":-15550,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Espenberg","ParentVolcano":"Espenberg","VolcanoID":"ak95","ParentVolcanoID":"ak95"},{"ID":2771,"Name":"Katmai Lethe Assemblage/Lethe Tephra","Description":"From Stevens (2012): \"The informally named Lethe volcaniclastic deposits (Pinney and Begét 1990, 1991a, 1991b; Pinney 1993) comprise an extensive suite of dacitic deposits, including pyroclastic flows, lahars, lahar-runout flows, and primary and reworked fallout tephra. These deposits are exposed in river gorges in the Valley of Ten Thousand Smokes as far as 1.0 mi (1.5 km) up-valley from the mouth of Windy Creek and extend about 3.1 mi (5 km) past Windy Creek in Overlook valley (Figure 5 [in original text]). Lethe deposits overlie Iliuk drift in the Windy Creek area and are overlain by and incorporated into Ukak and Katolinat drifts (Pinney and Begét 1991b, Pinney 1993). Organic silt immediately underlying the younger glacial deposits yields a minimum age of 12,640+/-100 RC yr B.P. for Lethe deposits (Pinney and Begét 1991a, Pinney 1993). Hildreth and others (2003) correlate the Lethe volcaniclastics to a remnant of a proximal pumice-and-scoria fall in the Katmai caldera rim, suggesting that the deposits were erupted from Mount Katmai. Lethe ash has been used as an important stratigraphic marker horizon at Iliamna and Naknek lakes (Kaufman and Stilwell 1997), and 185 mi (300 km) away on the Kenai Peninsula (Reger and others 1996). Organic material beneath the Lethe tephra on the Kenai Peninsula gives a maximum age for the tephra of 16,480+/-170 RC yr B.P. (Reger and others 1996), and lake-core studies in lower Cook Inlet suggest a minimum age of 13,730 RC yr B.P. (Rymer and Sims 1982, Riehle and others 2008). These dates correlate well with the minimum date from the Windy Creek area and indicate that the Lethe volcaniclastics were erupted between about 16,600 and 13,730 RC yr B.P.\"\r\nFrom Fierstein (2007): \"...Plinian to sub-Plinian dacitic eruption 12 to 16 ka that sent remobilized pumiceous debris down glaciercovered slopes to pond in lowlands beyond (the Lethe Assemblage)...\"\r\n\"Analyses of pumice clasts from the hcs and debris flows of the Lethe deposits overlap those of two pyroclastic units exposed on the rim of Katmai caldera (Fig. 20 [in original text]); (1) a 50-m-thick remnant of an orange-oxidized coarse proximal scoria fall zoned upward from dacite to andesite on the south rim, and (2) a sheet of grey agglutinated dacite fallout (described by Hildreth and Fierstein 2000) that widely caps the west rim, drapes the summit of peak 6128, and thickens into a pre-1912 crater (largely destroyed in 1912) (Figs. 3, 22 [in original text]). Pumice from these rim units are so similar that none of the whole-pumice or microprobe glass data discriminate between the two deposits; only the higher P2O5 in the Lethe pumice suggests an affinity with the south rim dacite. Fe-Ti oxide data, however, better discriminate between them. Oxide data from Lethe pumice deposits cluster tightly and yield higher MgO and lower TiO2 than oxides from pumice in the west-rim deposits (Fig. 21 [in original text]), suggesting the west rim agglutinate is not correlative with the Lethe tephra. Considering this, and that the whole-pumice and glass data show that the Lethe deposits did come from one of these two rim sources, and because the clasts on the south rim are oxidized orange like those in the remobilized deposits, we favor the south rim of Mount Katmai as the source for the Lethe volcaniclastics. Direct comparison with oxides from the Katmai south-rim deposits cannot be made because all are badly oxyexsolved and unsuitable for correlation. Glass shard data from what Reger and others (1996) call the \"Lethe Tephra\" -an ashfall layer widespread in late Pleistocene deposits on the Kenai Peninsula (260-380 km away)-are plotted with our data (Fig. 21a [in original text]) and corroborate their correlation with the \"Lethe volcaniclastics\". We thus prefer the term \"Lethe Assemblage\" (Hildreth and others 2000; Hildreth and Fierstein 2000, 2003) to refer to this collection of distal fall, medial remobilized deposits, and proximal agglutinate.\"\r\n\"The assemblage is widely overlain by several meters of Early Holocene till, and, wherever its base is exposed, it also rests directly on late Pleistocene till. From stratigraphic relationships in the Kenai Lowland, Reger and others (1996) inferred an age for the \"Lethe Tephra\" slightly younger than 16,000 14C years, B. P. For the Lethe Assemblage itself, we have obtained an older limiting age of 18,980+/-90 14C years B.P. for a rip-up clast of silty soil enclosed in the massive sand deposit near Windy Creek (Table 2 [in original text]). Pinney and Beget (1991) published an upper limiting age of 12,640+/-100 14C years B.P. for \"organic silt\" nearby, which they inferred from their interpretation of the local glacial deposits to be younger than the Lethe Assemblage. Thus, our best emplacement-age estimate for the Lethe Assemblage is between ∼12,000 and 16,000 14C years B.P., when a valley glacier still occupied the VTTS.\"","StartYear":-14050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-10050,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Katmai","ParentVolcano":"Katmai","VolcanoID":"ak147","ParentVolcanoID":"ak147"},{"ID":1191,"Name":"Aniakchak Tephra D/Pleistocene","Description":"From Davies and others (2016): \"Ager (1983, 2003) reports a 5 cm thick grey tephra near the base of cores taken from Puyak and Zagoskin Lakes on St Michael Island (Fig. 5 [in original text]) in western Alaska. Although no geochemical data were published with the original reports, they were analysed but did not match any known tephra at the time (Ager, 2003; pers. comm.). The original samples from both locations have been analysed here and new data are shown in Fig. 7 and Table 3 [of original text], along with analyses for a younger tephra from Zagoskin Lake that is correlated to the mid-late Holocene caldera-forming eruption (CFE II) of Aniakchak volcano (Riehle and others, 1987; UA 1602-see Table 4 in Section 5 [in original text] for details). The basal tephra present in both Zagoskin and Puyak lakes are correlative, have a glass morphology predominantly comprised of highly vesicular pumice shards, and are andesitic in composition. They also correlate with Tephra D from the Ahklun Mountains (Kaufman and others, 2012), and hence shall be referred to as such (Fig. 7 [in original text]). This indicates Tephra D is distributed well beyond south-western Alaska. The zones outlined on Fig. 7 [in original text] show the geochemical range of major element data produced from whole rock samples of Aniakchak CFE I and II (Bacon and others, 2014). Although these data are not directly comparable to EPMA glass data due to the incorporation of minerals, it does show that the relations between Tephra D and Aniakchak CFE II glass data (UA 1602) mirror that between the whole rock CFE I and II data for multiple elements. The offset seen for wt% FeOt and SiO2 are as expected given from the presence of common phenocryst phases (e.g. plagioclase). This suggests that Tephra D may also be sourced from Aniakchak.\"\r\n\"Tephra D is given a maximum age of 15,610+/-220 14C yr BP at Puyuk Lake, and a minimum age of 14,970+/-170 14C yr BP at Zagoskin Lake, although these radiocarbon dates are likely to be older than expected as they are bulk sediment dates (Ager, 2003; pers. comm.) Tephra D has a mean age of 15,505+/-312 cal yr BP from two sites (Kaufman and others, 2012) and this is believed to be a more reliable estimate for the tephra as the constraining dates are produced from plant macrofossils. These ages do not support a correlation between Tephra D and Aniakchak CFE I, which has a suggested maximum age from VanderHoek and Myron (2004) of 9470+/-40 14C yr BP. The apparent geochemical associations do, however, suggest that Tephra D may originate from an earlier eruption of Aniakchak that has not been reported from the proximal records. This is potentially due to the glacial erosion of pre-Holocene age deposits surrounding the Aniakchak volcano.\"\r\nFrom Bacon and others (2014): \"Pleistocene Aniakchak was a composite volcano that grew over a period of several hundred thousand years atop Jurassic-Tertiary sedimentary rocks by effusion of basaltic andesite to dacite lava. The Aniakchak edifice was smaller than those of other volcanoes with ~10 km diameter calderas in the eastern Aleutian arc, and it was repeatedly sculpted by ice during glacial intervals so that deep valleys were present at the end of the last glaciation. Basaltic magmas, with a range of incompatible element concentrations characteristic of arcs, were drawn from the mantle wedge into the deep crust beneath Aniakchak, where they were modified through crystallization differentiation and interaction with their surroundings in a deep crustal hot zone. Fractionated magmas that escaped upward further differentiated and partially to completely solidified to gradually build an intrusive complex, or mush column, in the mid to upper crust that was well developed by the end of the last glaciation.\"\r\n\"The concept of late Pleistocene Aniakchak that emerges is of a composite volcano of moderate size whose glacially sculpted summit would have been south of the center of the present caldera. Bedrock morphology of glacial valleys heading in Aniakchak lavas would have been essentially as now, with the exception of that of The Gates and Aniakchak River that was extensively modified by draining of the intracaldera lake. Birthday Creek glacial valley cut deeply into the southwest flank of the edifice and extended as a significant declivity well into the area above the present southwest caldera floor. The width and east-west trend of Birthday Creek valley near the modern caldera rim suggest that ice of sufficient volume to carve this large valley may have been sourced in a small late Pleistocene caldera.\"\r\n\"The Pleistocene eruptive history preserved by the edifice lavas has yet to be studied in detail. Reconnaissance sampling and geochemical analysis of about 30 specimens provides a general compositional range for Aniakchak erupted magmas over the probable several hundred thousand years during which the edifice was constructed (Nye and others, 1993). There doubtless exist materials emplaced during glacial conditions, so that a record of volcanism during different climatic conditions could be obtained through additional field study and argon geochronology. For the present report, we are limited to employing the geochemistry of edifice lavas as context for compositional diversity among products of postglacial Aniakchak.\"","StartYear":-13660,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":220,"StartQualifierUnit":"Years","EndYear":-13020,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":170,"EndQualifierUnit":"Years","Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":2791,"Name":"Koniuji 15200 yBP","Description":"From Jicha (2009): \"Four experiments on two samples (KON-07-01 and -02) of a clinopyroxene-phyric basaltic andesite flow along the southern shoreline gave a weighted mean 40Ar/39Ar age of 15.2+/-5.0 (2 sigma) (Figs.2-4 [in original text]).This lava flow contains large (\u003e1 cm) augite megacrysts similar to those found in the basalts of Roundhead volcano on Kanaga Island ~250 km to the west (Brophy and others, 1999).\"\r\n\"40Ar/39Ar age determinations indicate that it is a young stratovolcano that emerged above sea level at ~15.2 ka.\"","StartYear":-13250,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":5000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Koniuji","ParentVolcano":"Koniuji","VolcanoID":"ak168","ParentVolcanoID":"ak168"},{"ID":1721,"Name":"Aniakchak Precaldera Dacite","Description":"From Bacon and others (2014): \"Two lava flows and several pyroclastic deposits are younger than the last major glacial advance but preceded the Aniakchak II caldera-forming eruption.\"\r\n\"A blocky flow of dacite lava is present on the northeast flank of Aniakchak volcano (fig. 4 [in original text], included in unit Qbn). Compositional affinity of the lava with deposits on the caldera rim indicates that the flow likely postdates Aniakchak I. Dreher (2002, p. 17) reported Aniakchak II lithic breccia resting on the lava.\"\r\nNeal and others (2001) also report a dacite lava flow (on northwest flank?).","StartYear":-12050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-1480,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":1731,"Name":"Aniakchak Precaldera Rhyodacite","Description":"From Bacon and others (2014): \"Two lava flows and several pyroclastic deposits are younger than the last major glacial advance but preceded the Aniakchak II caldera-forming eruption.\"\r\n\"A second precaldera silicic lava flow or dome is exposed in the cliff at the caldera rim north of The Gates (figs. 5Band 8A [in original text]; also included in unit Qbn in map figures). The rhyodacite composition of the lava is more differentiated than that of the northeast flank lava but is virtually identical to that of the overlying lower Black Nose Pumice, which suggests that the lava represents an early phase of the Black Nose Pumice eruption sequence. The lava appears to overlie Aniakchak I deposits.\"","StartYear":-12050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-1480,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":3811,"Name":"Redoubt Harriet Point Debris Avalanche","Description":"From Beget and Nye (1994): \"A previously unrecognized debris avalanche deposit from Redoubt Volcano covers almost 40 km 2 in the lower Redoubt Creek area (Beget and Nye, 1990). We name this deposit the Harriet Point debris avalanche for excellent exposures in sea-cliffs near Harriet Point (Figs. 2, 3 [in original text]). The deposit forms a light-yellow to gray bouldery, hummocky layer 5-15 m thick that can be traced in outcrops along almost 7 km of sea cliffs north of Redoubt Creek. The yellowish avalanche deposit typically overlies gray clays and silt of late Pleistocene age, which appear in part to consist of the Bootlegger Cove Clay (Riehle and Emmel, 1980). The avalanche itself is overlain in most places by 1-2 m of peat containing several thin tephra layers. In a few areas, particularly on the northeast border of the deposit, it is overlain by coarse alluvium.\"\r\n\"The Harriet Point debris avalanche is the largest and most extensive such deposit known associated with any Cook Inlet or Alaska Peninsula volcano. Several debris avalanches have been mapped at Augustine Volcano, but these travelled no more than 8-12 km (Siebert and others, 1987; Beget and Kienle, 1992). A large prehistoric debris avalanche preserved south of Spurr Volcano travelled about 20 km (Nye and Turner, 1990). It is not possible to accurately estimate the original volume of the Harriet Point deposit as it has been completely eroded away near Redoubt Volcano where it was probably originally the thickest. However, a comparison of its areal extent to that of the less extensive 1980 Mount St. Helens avalanche suggests it may originally have been of similar or somewhat greater volume (Fig. 7 [in original text]). The Mount St. Helens avalanche deposited about 2.8 km 3 of debris (Glicken, 1991).\"\r\n\"The Harriet Point debris avalanche must be no older than latest Pleistocene in age, as it clearly postdates the deglaciation of much of Cook Inlet, including the lower Redoubt Creek drainage ca. 14-15 kyr B.P. (Hamilton and Thorson, 1983; Schmoll and Yehle, 1986). The avalanche deposit overlies clays and silt thought to correlate with the Bootlegger Cove Formation (Riehle and Emmel, 1980). The Bootlegger Cove Clay has been dated at other localities to ca. 13-15 kyr B.P. (Schmoll and others, 1972).\"\r\n\"Several radiocarbon dates were obtained from peat sections that immediately overlie the avalanche near Harriet Point (Table 1 [in original text]). The oldest date was 10,460+/-80 yr B.P., obtained from a horizon separated from the avalanche by 10-20 cm of silt. There was no soil development visible below the peat, within the silt, or on the avalanche surface, which suggests that this date constitutes a close upper limiting age. The available data therefore suggest the Harriet Point debris avalanche was deposited sometime between 10.5 and 13 kyr B.P.\"","StartYear":-11050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-8510,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":80,"EndQualifierUnit":"Years","Volcano":"Redoubt","ParentVolcano":"Redoubt","VolcanoID":"ak231","ParentVolcanoID":"ak231"},{"ID":3651,"Name":"Okmok CFE I","Description":"From Beget and others (2005): \"The oldest deposits of Okmok Volcano that post-date the last ice age record a complex series of very large eruptions culminating in the development of a summit caldera (fig. 5 [in original text]). This late Pleistocene-early Holocene eruption generated voluminous deposits with compositions ranging from rhyodacite (70 wt. % SiO2) to basaltic-andesite (54 wt. % SiO2). It produced broadly synchronous welded pyroclastic flows, thick surge deposits, and debris avalanche deposits that together are as much as 100 meters thick on the northern flanks of Okmok Volcano. Pyroclastic flows and surges produced during these eruptions traveled to the coast and far out to sea around the volcano. The most distant deposit preserved on land was produced by a flow that crossed the waters of 7-kilometer-wide Umnak Pass to the westernmost part of Unalaska Island, traveling at least 21 kilometers from the vent. Surge deposits from this eruption also crossed Mt. Idak (fig. 2 [in original text]), climbing over a 200-meter scarp at a distance of 15 kilometers from the caldera rim. A debris avalanche also occurred at this time, but the debris avalanche deposits are very poorly preserved. The debris avalanche, found only on the north flank of the volcano, probably occurred during collapse of the former summit during the creation of the large caldera. Radiocarbon dates from directly beneath the pyroclastic flow deposits from this first caldera-forming eruption on westernmost Unalaska Island, and dates associated with distal volcanic ash deposits from these eruptions found near the city of Unalaska 100 kilometers to the east (Bean, 1999), both indicate the first caldera-forming eruption occurred about 12,000 years ago.\"\r\nFrom Miller and Smith (1987): \"The Okmok volcanic center, Umnak Island (Fig. 1 [in original text]), is a large basaltic composite volcano with a caldera system marking the summit area. This system consists of two large partially overlapping calderas (Byers, 1959), each with an estimated diameter of about 10 km. Postglacial ash-flow tuffs exposed in sea-cliff exposures on the northwest side of the volcano are locally separated by a lava flow 6-9 m thick (Miller and Smith, 1975). A hiatus between extrusion of the lava and deposition of the upper ash-flow sheet is indicated by a well-developed erosional surface on the lava flow; in places, stream channels were cut through the lava flow and later filled by the younger ash flow. The occurrence of two major ash-flow units strongly supports the probability of two major caldera-forming eruptions in Holocene time.\"\r\nFrom Larsen and others (2007): \"No soils exist beneath the Okmok I unit on Umnak Island. However, one radiocarbon date from a thin soil between the Okmok I deposits from on westernmost Unalaska Island (03JLOK64), and another from beneath distal tephras near the city of Unalaska about 100 km away, indicate the Okmok I eruption occurred about 12,000 14C yBP (Bean, 1999; Begét and others, 2005).\"\r\n\"The Okmok I basal surge and fall layers comprise 4-6 km3, the main pyroclastic flow deposits are 14 to 21 km3, and the top surge layers are 2 to 3 km3. The total volume estimate for Okmok I on Umnak Island ranges from ~21 to ~31 km3, within the bounds described above. These estimates do not account for the estimated total volume of the depression thought to remain from the Okmok I eruption (~50 km3), or the volume of material that was deposited into the oceans.\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2017) reports a magnitude of 6.7, bulk eruptive volume of 50 cubic km and a dense rock equivalent eruptive volume of 26 cubic km for the eruption.","StartYear":-10050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Okmok","ParentVolcano":"Okmok","VolcanoID":"ak206","ParentVolcanoID":"ak206"},{"ID":3661,"Name":"Okmok Middle Scoria","Description":"From Wong (2004): \"The Middle Scoria Unit (M.S.) of Okmok Volcano is a basaltic andesite (~ 54 wt. % SiO2) fall deposit that is stratigraphically located between two caldera-forming eruptions (~ 12,000 and 2050 y B.P.). Stratigraphy, geochemistry, vesicularity, and crystallinity data imply that the M.S. erupted in three phases that began with an initial phreatomagmatic phase followed by a sub-Plinian phase caused by rapid ascent of magma. The sequence culminates with short-lived Vulcanian eruptions that demonstrate a strong magmatic influence and a possible decrease in ascent rate. The M.S. covers ~ 300 km2 and averages about 2 m thick. Estimates from this work suggest a total eruptive volume of 1.4 km3, an eruption column ~ 9-14 km high, and a mass discharge rate of ~ 8 x 106 kg/s. These values correspond with the low end value of other sub-Plinian and phreatomagmatic eruptions. The changes seen in the eruptive phases of the M.S. are a result of variations in the magma dynamics and access of external water, likely from snow or ice.\"\r\n\"The M.S. has a uniform composition of 54 wt. % SiO2 (Figure 26 [in original text]). Verifying homogeneous glass analyses was difficult because of the microlite-enriched groundmass. The glass chemistries determined could not be used to systematically constrain relative changes within the eruptive layers (Figure 25 [in original text]). Glass data of the M.S. proved ineffective for identifying heterogeneities or magma mixing on a fine scale. However, the analyzed glass data indicate a relatively homogeneous magma with respect to whole rock compositions because there is no significant change in composition to indicate a re-injection of new magma or magma mixing. However, the eruption of the M.S. can be modeled as a three phase eruption that demonstrates both magmatic and phreatomagmatic eruptive behavior (Figure 28 [in original text]).\"\r\n\"The initial eruptive phase of the Middle Scoria had a phreatomagmatic component, seen in the characteristics of the basal ash. The basal ash is highly fragmented and relatively fine-grained compared to the other layers of the M.S., thus the interaction with water was relatively efficient. Evidence for an initially high, yet short-lived phreatomagmatic component is apparent in the blocky grain morphologies. The water source was likely snow or a glacier that melted and drained away from the vent, exposing the magma to the atmosphere (Wilson and Head, 2002). Although the presence of caldera lakes was likely, the cold temperatures required to inhibit the formation of accretionary lapilli supports snow or glacier conditions. Snow in the winter and a stagnant glacier covering about 1.5 km are present within the current caldera near Cone A (Beget and others, in press). An overlying glacier must be relatively thin (\u003c 150 m) though in order to melt fairly rapidly (Smellie, 2000). When ice melts to water, the initial volume reduction would reduce the overpressure as the eruption progresses. The interaction involves significant transfer of water to steam, which increases condensation, thus lowering the heights achieved by the eruptive clouds because of an increase in density from the volumetric change of water (Wilson and Head, 2002). There is no evidence for near-vent eruptive products, nor was a detailed analysis of componentry undertaken, but identifying sources of external water are still possible. It is possible that the central erupting regime was freely vesiculating in simultaneous production or in rapid succession with a marginal (edge) interaction with water, as was the case for the actively vesiculating nature of the 1790 AD Keanakakoi ash (McPhie, 1990). However, interaction with groundwater would require a significant amount of recharge to produce relatively continuous phreatomagmatism evident in the third eruptive phase. The initially high pressures required for a fast ascent rate would preclude conditions of groundwater entry as the pressure of surrounding groundwater would have to exceed the conduit pressure. This process is also true for magma-aquifer interaction. Interaction with an aquifer would yield high lithic contents, however, this did not happen because dense juveniles are also dominant. The thickness of Jl implies the water source could not have been ubiquitous, thus the caldera floor was likely above the water table.\"\r\n\"The second eruptive phase was likely a continuation of a drying out of the first phase as the rapid ascent and high mass discharge of the magma prevented water interaction. Drying out of the snow or ice would enhance conditions for formation of Plinian eruption plumes (Head and Wilson, 2002). Waning water interaction is apparent by the coarse grain population of J l, which demonstrates purely magmatic fragmentation by vesiculation of a relatively strong eruptive pulse that sustained a high convective column (Walker, 1981). Jl is likely the only true layer that should plot in the sub-Plinian field because it shows no evidence for interaction with water.\"\r\n\"With a decreasing magma ascent and a slightly lower mass discharge, any residual heat would melt the snow/ice and produce a small lake, possibly frozen, for the third phase. The lithic to juvenile-rich layers demonstrate the cyclic nature of intermittent Vulcanian style eruptions. A less gaseous magma with a slightly reduced ascent rate is apparent because of the increase in lithic and dense juvenile clasts, which imply increased water availability. When external water is incorporated into the magma, the vent usually widens (Wilson and Head, 1994). Reverse grading in the lithic rich layers is likely the result of vent widening. A subtle increase in eruptive energy from mass discharge estimates for J2 is evident, and is likely responsible for the reverse grading in juvenile rich layers. The ascent rate varied as newly arriving magma or mixing in the column was ongoing based on increases in vesicularity in the intermittent juvenile rich layers (Houghton and others, 1996), as well as the relatively constant eruptive height estimated for the column that produced LI. Therefore, even though the upper layers are not highly fragmented, they are more consistent with typical Vulcanian style eruptions. The negative correlations found for the crystallinity and vesicularity data demonstrate not only that the ascent of the magma varied, but that the interaction with external water was also variable.\"\r\nFrom Beget and others (2005): \"At least four significant eruptions of mafic scoria (~54 wt. % SiO2; Wong, 2004) occurred during the time period between the older and younger caldera-forming eruptions and these are mainly found to the northeast and south of Okmok caldera. These units are poorly understood, yet contain evidence for explosive interactions between external water and magma, producing phreatomagmatic deposits. The most extensive of these is described in Wong (2004), and consists of thick deposits of scoria and rock fragments deposited to the south and east of the present caldera.\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2017) reports a magnitude of 4.6, bulk eruptive volume of 0.245 cubic km and a dense rock equivalent eruptive volume of 0.145 cubic km for the eruption.","StartYear":-10050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-100,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":50,"EndQualifierUnit":"Years","Volcano":"Okmok","ParentVolcano":"Okmok","VolcanoID":"ak206","ParentVolcanoID":"ak206"},{"ID":3671,"Name":"Okmok 12000 yBP","Description":"From Beget and others (2005): \"In addition to eruptions within the caldera, more than 20 small cinder cones and lava flows occur high on the upper north and northeastern flanks of the volcano and around the caldera rim, and at least five flank cones lie on the southwest flank of the volcano. These features are relatively uneroded and most are likely post-glacial in age and also pre-date the most recent caldera-forming eruption and so are less than 12,000 years old. The largest flank eruption produced a 200-meter-high lava spatter cone and a voluminous lava flow that forms cliffs at Cape Aslik (fig. 2 [in original text]). The lava flow covers more than 15 square kilometers on the west flank of the volcano, involves about 0.5 cubic kilometers of lava, and is locally buried by tephra produced during the younger caldera eruption about 2,000 years ago.\"","StartYear":-10050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-100,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":50,"EndQualifierUnit":"Years","Volcano":"Okmok","ParentVolcano":"Okmok","VolcanoID":"ak206","ParentVolcanoID":"ak206"},{"ID":1351,"Name":"Akutan Late Pleistocene/Early Holocene Caldera","Description":"From Richter and others (1998): \"About 2 km southwest of the present caldera, remnants of an older caldera wall, probably of late Pleistocene age, crop out through the extensive tephra and lahar deposits that mantle Akutan’s summit area.\"\r\nFrom Miller and others (1998): \"The vestige of a larger caldera, of probable late Pleistocene age and at least in part older than the cone of Akutan Peak, extends 1.5 km southwest of Akutan Peak and is terminated to the north by the younger caldera. Small glaciers fill the older crater and lie within the southwest and southeast margins of the younger caldera.\"\r\nFrom Waythomas and others (1998): \"The age of the eruption that formed the older caldera is not known but is possibly of late Pleistocene or early Holocene age.\"\r\nFrom Waythomas (1999): \"Remnants of an \"older\" caldera rim southwest of the present Akutan caldera protrude above a thick mantle of late Holocene pyroclastic-flow and tephra deposits (Fig. 8 [in original text]). Volcaniclastic deposits at the head of Reef Bight (Fig. 8 [in original text]) likely formed during one or more early Holocene eruptions possibly associated with the formation of the \"older\" caldera.\"","StartYear":-9750,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":4381,"Name":"Little Sitkin CFE II","Description":"From Miller and others (1998): \"A second stratovolcano was constructed almost entirely of lava flows (unit Qd) within Caldera One and attained a height of about 900 m. A cataclysmic eruption, possibly in early post-glacial time, resulted in the formation of a second, smaller caldera (Caldera Two) that partially destroyed this cone. Caldera Two is elliptical in outline and measures 2.7 by 4 km; the inferred eastern and southern margins are coincident with those of Caldera One. Field relations suggest that the northern boundary of Caldera Two is a hinge along which a large block, comprising most of the Caldera One stratovolcano, was tilted southward during the caldera eruption. The highest peak on the island is on the post-caldera remnant of the second cone. \r\n\"A deposit of partly welded tuff up to 100 m thick (unit Qp) extends from the remnant cone northwest across the Caldera Two boundary fault, to slightly beyond the inferred location of the Caldera One boundary fault. The deposit is thought to have been emplaced by one of more pyroclastic flows, possibly associated with formation of Caldera Two\"","StartYear":-9750,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Little Sitkin","ParentVolcano":"Little Sitkin","VolcanoID":"ak182","ParentVolcanoID":"ak182"},{"ID":4391,"Name":"Spurr CFE","Description":"From Miller and others (1998): \"Capps (1929) suggested that a summit caldera, largely buried by ice, is associated with Mount Spurr.\r\nLater, Juhle and Coulter (1955) disagreed with the caldera interpretation suggesting that the peaks around Mount Spurr only coincidentally resemble the rim of a large subsidence structure. Most recent studies, however, suggest that ancestral Mt. Spurr, constructed during late Pleistocene time (Turner and Nye, 1986), was partially destroyed by a major Bezymianny-type eruption possibly as late as early Holocene time (Riehle, 1985; Nye and Turner, 1990). The eruption produced a voluminous volcanic debris avalanche and subsequent pyroclastic flows that resulted in the formation of a 5- to 6-km-diameter explosion caldera (fig. 7). The volcanic debris avalanche contains blocks as much as 100 m in diameter and traveled a minimum of 25 km. The overlying pyroclastic flows are partially welded and are composed chiefly of high silica andesite.\"","StartYear":-9750,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Spurr","ParentVolcano":"Spurr","VolcanoID":"ak260","ParentVolcanoID":"ak260"},{"ID":4421,"Name":"Yunaska CFE II","Description":"From Miller and others (1998): \"The eastern volcanic center, to which all recent Yunaska volcanism has been attributed, has been described by Nicolaysen and others (1992) and Lamb and others (1992) in preliminary reports as a large shield volcano topped by two overlapping calderas. No age has been reported for caldera formation but the fresh morphology of the younger caldera and the non-glaciated nature of the associated pyroclastic rocks suggests it at least is Holocene in age. The older of the two calderas (caldera CI, Lamb and others, 1992) has a diameter of 10-13 km, the younger (caldera CII) about 3 km. Low ridges and peaks along the northern and eastern shores of the island define the postulated caldera (see physiographic descriptions in Sekora, 1973).\"","StartYear":-9750,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Yunaska","ParentVolcano":"Yunaska","VolcanoID":"ak329","ParentVolcanoID":"ak329"},{"ID":2281,"Name":"Edgecumbe Tephra set (includes Mount Edgecumbe Dacite (MEd) Tephra)","Description":"From Beget and Motyka (1998): \"A 5- to 15-m-thick deposit of dacite lapilli on the west side of Kruzoff Island is the proximal equivalent of the most widely dispersed Edgecumbe tephra in southeastern Alaska.\"\r\n\"We obtained essentially identical dates of 11,350+/-70 (B-77054) and 11,230+/-70 14C yr B.P. (B-77056) from peat immediately below geochemically correlative dacitic tephra at a newly discovered tephra locality at Greentop on Yakobi Island (Fig. 1 [in original text]). Because these five dates all clearly pertain to the climactic eruption of dacitic tephra, we average them and calculate a date of 11,250+/-50 14C yr B.P. for the major late Pleistocene dacitic tephra eruption of Mt. Edgecumbe volcano.\"\r\n\"These eruptions produced a related group of deposits during a short interval of volcanism; such groups have been referred to as tephra \"sets\" elsewhere in Alaska and North America (Mullineaux, 1986, 1996). We suggest that the tephra deposits produced at Mount Edgecumbe and nearby vents at 11,250+/-50 14C yr B.P. be informally designated as set ME. This designation would follow the North American convention of using letters in informal tephra nomenclature, while avoiding confusion with numerous other tephras in Alaska which have single-letter designations. There is only one dacite tephra deposit within set ME, which we have informally named layer MEd.\"\r\n\"At proximal sites, layer MEd can be identified visually by its thickness, light color, and texture. At distal sites, layer MEd can be identified by electron microprobe (EMP) analyses or other geochemical methods...A 15-cm-thick ash deposit at a new site along lower Montana Creek in Juneau is composed almost entirely of dacitic glass shards and also marks the most southerly and easterly known occurrences of this tephra. A 10-cm-thick ash deposit at the new Greentop locality to the north also contains abundant dacite glass and constitutes the most westerly known locality of this tephra.\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2017) reports a magnitude of 5.9, bulk eruptive volume of 7.0 cubic km, a dense rock equivalent eruptive volume of 3.40 cubic km, and an airfall tephra deposit volume of 6.5 cubic km for the eruption.","StartYear":-9300,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Edgecumbe","ParentVolcano":"Edgecumbe","VolcanoID":"ak90","ParentVolcanoID":"ak90"},{"ID":3011,"Name":"Roundtop 10000 yBP","Description":"From Carson and others (2002): \"This horizon [Horizon B] consists of scattered 1-2 cm pumice lapilli, gray to light brown, dispersed in a 10-15 cm thick sediment horizon. It was collected at seven outcrops in the ColdBay area, on the west and northeast shores of ColdBay at sites 6, 9, 10, 11, 13, 23, and 25 (Fig. 5 [in original text]). At all locations, the horizon was collected either beneath the Funk/Fisher ash or directly above the late Wisconsin diamicton. EMPA of the samples consistently yielded total weight compositions well below 98.0 (e.g. sample 96JF9A from site 6 [in original text], on-line Appendix 1). When oxygen was explicitly analyzed in these samples, total weight percent compositions were ~100.0%, indicating that the anomalously low initial values were the result of hydration of the samples. For these samples alone, the original totals were normalized to 100.0% for comparison and correlation (Froggatt, 1992). The normalized totals represent a horizon with the most silica-rich horizon collected, with ~77 wt% SiO2 (Table 3 [in original text]). Independently of major-element chemistry, the horizon was correlated based on stratigraphic position below the Funk/Fisher ash and on the size of large pumice fragments. Once the EMP values were normalized to 100.0%, the SC values were 0.95-0.98. Although there are no radiocarbon dates directly associated with this horizon, its stratigraphic position indicates it was deposited sometime between the deglaciation of Cold Bay and deposition of the Funk/Fisher ash.\"\r\n\"Horizon B correlates to the proximal samples from the early Holocene eruption of Roundtop volcano (Miller, 1999). The combination of SC=0.95, similar outcrop descriptions of coarse lapilli \u003e1cm in diameter dispersed in sediment, and the stratigraphic position of this deposit below the Funk/Fisher ash demonstrates that Horizon B is the product of an eruption of Roundtop volcano dating to 9100-10,000 14C yr BP.\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2017) reports a magnitude of 5, bulk eruptive volume of 7.0 cubic km and a dense rock equivalent eruptive volume of 3.04 cubic km for the eruption.","StartYear":-8050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-7150,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Roundtop","ParentVolcano":"Roundtop","VolcanoID":"ak236","ParentVolcanoID":"ak236"},{"ID":2661,"Name":"Kanaga T2","Description":"From Waythomas and others (2001): \"Groups of tephra deposits so defined indicate that at least 11 eruptions of Kanaga Volcano have occurred since about 11 ka. Most of these eruptions were probably sub-Plinian to Plinian, producing moderately vesicular dacitic pumice lapilli tephra deposits ranging in thickness from a few centimeters to more than 1 m (table 2 [in original text]).\"\r\n\"Pumice-lapilli fall deposit.\"","StartYear":-7737,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-6868,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kanaga","ParentVolcano":"Kanaga","VolcanoID":"ak144","ParentVolcanoID":"ak144"},{"ID":2651,"Name":"Kanaga T1","Description":"From Waythomas and others (2001): \"Groups of tephra deposits so defined indicate that at least 11 eruptions of Kanaga Volcano have occurred since about 11 ka. Most of these eruptions were probably sub-Plinian to Plinian, producing moderately vesicular dacitic pumice lapilli tephra deposits ranging in thickness from a few centimeters to more than 1 m (table 2 [in original text]).\"\r\n\"Pumice-lapilli fall deposit.\"\r\nWaythomas and others (2001) correlated their T1 tephra with the basal pink ash on Adak Island, described by Kiriyanov and Miller (1997) (their Ad-6). \r\nFrom Kiriyanov and Miller (1997): \"AD-6 ash is as thin as 0.5-1 cm and consists of pink silt- and clay-size ash. The thickness of the layer and the particle size of the ash are invariable in all the sections examined. The distinctive features of its mineral composition are a considerably high glass content (64%), the significant content of green hornblende (6%), and the presence of brown hornblende (3%) and pyroxenes (1%). The total amount of glass and plagioclase is as large as 80% (Fig. 5 [in original text]). The carbon-14 dating yielded an age of 9500-9600 years (Table 1 [in original text]).\"","StartYear":-7650,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-7550,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kanaga","ParentVolcano":"Kanaga","VolcanoID":"ak144","ParentVolcanoID":"ak144"},{"ID":1361,"Name":"Akutan Harbor Ash","Description":"From Waythomas and others (1998): \"Radiocarbon dates on peat and soil organic matter from bank exposures in the Akutan Harbor area indicate that volcanic ash began accumulating on Akutan Island about 9500 years ago. Some of the volcanic ash layers found in this area are distinctly light colored and these ash layers could be from distant volcanoes, probably west of Akutan Island (fig. 1 [in original text]).\"","StartYear":-7550,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":3071,"Name":"Shishaldin Cape Lapin Debris Avalanche","Description":"From Beget and others (2002): \"The largest known eruption of Shishaldin Volcano occurred about 9,500 years ago when the summit of Shishaldin Volcano collapsed to produce the large Cape Lapin debris avalanche. This giant landslide traveled more than 20 kilometers north to the Bering Sea, burying the northwest flank of Shishaldin Volcano and nearby areas of Unimak Island. The modern symmetrical cone of Shishaldin has completely regrown since this collapse event (Begét and others, 1998).\"","StartYear":-7550,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":1201,"Name":"Aniakchak CFE I","Description":"From Bacon and others (2014): \"The oldest recognized postglacial explosive eruption, andesitic Aniakchak I, left nonwelded ignimbrite in valleys below the edifice and fines-poor welded ignimbrite or agglutinated fall deposits high on its flanks between ca. 9,500 and 7,000 years ago. A small caldera may have collapsed at the source of the ignimbrite, likely just west of the present Vent Mountain. Aniakchak I andesite is geochemically distinct among the postglacial Aniakchak suite for its high K2O, Zr, and other incompatible-element contents.\"\r\n\"Aniakchak I and andesitic Aniakchak II exposures can be indistinguishable in the field. Where stratigraphic evidence for a pre-3,400-yr B.P. age is lacking, however, these units can be readily identified by their chemical compositions. Even though their silica concentrations and crystal contents are similar, Aniakchak I andesite has uniquely high K2O, Zr, and many other incompatible-element concentrations (see \"Geochemistry\" section [in original text]). Systematic search for Aniakchak I using geochemical fingerprinting has not been done, so the true maximum extent of pyroclastic flows from that eruption remains to be determined.\"\r\n\"Deposits of unconsolidated and partly welded andesite bombs and ash found low in north-northwest flank gully exposures, in Birthday Creek drainage and Birthday Pass, and below the caldera rim north of The Gates have distinctive Aniakchak I chemistry. These are considered to have been emplaced by pyroclastic flows during one or a few closely spaced eruptions that constitute the Aniakchak I event. The deposits in valleys clearly postdate the last major glacial advance. Large patches of Aniakchak I partly welded ignimbrite, consisting of flattened bombs as large as ~1 m and lithic fragments in an indurated matrix, are present on north and south sides of the floor of the Birthday Pass beheaded glacial valley at elevations between ~2,100 ft (640 m) and ~2,450 ft (750 m) asl (fig. 6B; see also fig. 10A [in original text]). Vertical cooling joints cut the entire ~30-m-thick exposure on the north side of the valley, where differences in induration suggest three or more flow units within a single cooling unit. Possibly, cliff exposures of these remnants of partly welded Aniakchak I ignimbrite were quarried by an early Holocene glacier that originated higher on ancestral Aniakchak, before formation of the caldera that we associate with Aniakchak II. The implication is that the Aniakchak I eruption was not accompanied by caldera collapse or, if a caldera formed, it either was too small to engulf the high-edifice source of the Birthday Creek glacier or it rapidly filled with ice that then spilled out Birthday Pass. Alternatively, presence of partly welded Aniakchak I ignimbrite on either side of Birthday Pass but not in the center of the valley could reflect deposition of ignimbrite along the margins of a glacier that occupied the upper valley at the time of the eruption. In that scenario, nonwelded ignimbrite lower in Birthday Creek valley was deposited in the valley floor below the terminus of the glacier, now marked by a low north-north-west-trending ridge that may be the glacier’s terminal moraine 1.8 km west of the pass at ~1,850 ft (560 m) elevation (see fig. 7 [in original text]). In that case, the glacier could have been beheaded by caldera collapse associated with the Aniakchak I eruption.\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2016) reports a magnitude of 6.0, bulk eruptive volume of 30 cubic km and a dense rock equivalent eruptive volume of 12 cubic km for the Aniakchak I caldera-forming eruption.","StartYear":-7550,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-5050,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":1751,"Name":"Aniakchak Precaldera Pyroclastic","Description":"From Bacon and others (2014): \"A meter or more thickness of unconsolidated deposits overlie Aniakchak I material and underlie the Black Nose Pumice in the exposure north of The Gates shown in figure 6C (\"unconsolidated deposits\"). The juvenile clasts in these deposits are dacite pumice. The sequence consists of ≤1 cm of buff ash, 1 cm of gray ash, 15 cm of pumice fall with obsidian chips, 5 cm of dark gray ash, 1 m of pumice fall with ≤0.5 cm obsidian chips and rare bombs as large as 30 cm, and 1 m of ashy probable surge deposit. The two uppermost beds are erosionally truncated. Additional work on tephras, below ash from Black Peak in flank exposures such as shown in figure 6A and in distal exposures studied by VanderHoek (2009), may establish correlations with the caldera rim deposits.\"","StartYear":-7550,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-5050,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":2371,"Name":"Fisher Tuff/Funk Ash/CFE","Description":"From Miller and Smith (1987): \"Fisher caldera, near the west end of Unimak Island (Fig. 1 [in original text]), is one of the largest calderas in the entire Aleutian arc-diameter greater than 11 km. The caldera is surrounded by a thick ash-flow sheet deposited by highly mobile flows (Miller and Smith, 1977).\"\r\n\"The ash-flow tuffs fill glaciated valleys and are therefore Holocene in age. An organic layer directly beneath the ash-flow tuff on the north side of the island yielded a 14C age of 9120+/-200 yr (sample 2, Table 1 [in original text]), which would be a maximum age for the caldera-forming eruption. Support for this date as the approximate age of the eruption comes from 14C dates (Funk, 1973) determined for a 10- 50-cm-thick pumice-rich tephra unit in the Cold Bay area 120 km east of Fisher (Fig. 1 [in original text]). Organic material directly beneath this tephra unit yielded 14C ages of 9660+/-615 and 10,625+/-550 yr. Granulometric, statistical, and isopach analyses of the tephra deposits by Funk indicate that they were deposited during one pulse of activity from a source on Unimak Island within 180 km of Cold Bay. The climactic eruption of Fisher, the closest caldera west of Cold Bay, is a logical but not unequivocal candidate for the source of the tephra.\"\r\nFrom Stelling and others (2005): \"Fisher Caldera formed during a single, three-phased eruption 9372+/-198 14C years ago. Each phase produced a distinct deposit, which we collectively call the Fisher Tuff: a Plinian dacitic pumiceous fall deposit dispersed to the northeast, followed by a voluminous pyroclastic flow containing banded pumice of mingled dacite and basalt distributed predominantly to the north, followed by a dacitic pyroclastic flow distributed to the south and west (Fig. 3B [in original text]). At its most proximal localities, the northeastern fall deposit is up to 10 m thick and abruptly changes ~2/3 up-section from a lower tan pumice to an upper slightly coarser, gray pumice. The tan and gray pumice layers are compositionally identical (67 wt.% SiO2), and the change in color may reflect differences in the degree of oxidation. The gray (darker) CFE pumices have greater vesicularity than the pink, opposite to the observations of Klug and Cashman (1994) who noted correlations between color changes and pumice vesicularity. Although a thorough analysis of the caldera-forming deposits is still in progress, the abrupt coarsening of pumice clasts at the color break may indicate an increase in mass flux during the production of the gray pumice.\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2017) reports a magnitude of 6.7, bulk eruptive volume of 56 cubic km, dense rock equivalent eruptive volume of 23.3 cubic km  and airfall tephra volume of 50 cubic km for the eruption.","StartYear":-7422,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":198,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Fisher","ParentVolcano":"Fisher","VolcanoID":"ak100","ParentVolcanoID":"ak100"},{"ID":2871,"Name":"Mageik Thick Orange Tan Ash","Description":"From Fierstein (2007): \"The oldest flows from East Mageik (unit \"meo\" of Hildreth and Fierstein 2003) have more degraded surfaces than their younger counterparts, although they are not obviously ice-scoured...Tephra deposits possibly associated with this eruptive episode are three older ash layers identified in the Angle Creek key section: the bluish-grey ash (just below K-2500G: ∼6,000-6,700 14C years B.P.), the thick gritty salmon ash (K-2500E: underlying peat is 8430+/-115 14C years B.P.) and the thick orange-tan ash (K-2500B: ∼9,260 14C years B.P.). Glass shards from the thick gritty salmon ash span a wider SiO2 range (74-78 wt.%) than those from the bluish-grey and the thick orange-tan (74-76 wt.%) ashes, while oxide data for all three ash layers overlap (Fig. 23 [in original text]). Microprobe data for these ash layers are so similar to those from younger East Mageik tephra that I am fairly confident they, too, are from East Mageik. The total eruptive volume of the East Mageik lavas is 5-6 km3, to which the dacitic falls and one small andesitic pyroclastic-flow deposit preserved locally atop \"meo\" add no more than 0.1 km3 (Hildreth and Fierstein 2000). Thus, over a period of ∼7,000 years, the preserved tephra record suggests there may have been at least six eruptive episodes from East Mageik plus one phreatic event, each separated by as little as 100 years to as much as 2,700 years.\"\r\n\"A 4 to 6-cm thick light orange-tan ash stands out sharply near the base of this section in Angle Creek (K-2500B, Fig. 3 [in original text]). Very fine-grained (Md=0.09 mm), it lies 10 cm beneath the greenish-brown ash and has no correlatives in any of our measured sections throughout the district. Compositionally similar to other Mageik tephras (75-76% SiO2; 1.5-2.0% CaO; glass and oxide microprobe data, Fig. 13 [in original text]), it is possible that this is another ash layer with a source at East Mageik. If so, then this would be the oldest (preserved) layer from a series of tephras erupted between ∼9,200 and ∼2,400 14C year B.P. from East Mageik.\"","StartYear":-7310,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mageik","ParentVolcano":"Mageik","VolcanoID":"ak187","ParentVolcanoID":"ak187"},{"ID":3021,"Name":"Seguam 9100 yBP","Description":"From Jicha and Singer (2006): \"At 9 ka, Wilcox volcano partially collapsed forming a 4-km-wide crater. The sector collapse was accompanied by an explosive lateral blast, which deposited a 0.45 km cubed dacitic ignimbrite (dig) to the northwest of the edifice. This sequence of events was likely similar to those during the May 1980 eruption of Mount St. Helens (Christiansen and Peterson, 1981) and the October 1902 eruption of Santa María volcano in Guatemala (Williams and Self, 1983). The dacitic ignimbrite retains a relatively uniform thickness of 80-100 m for 4 km until it reaches the northern shoreline. Because offshore bathymetry is not available, the distal extent of the ignimbrite is unknown, but it is clearly recognizable 10 km north of the coastline in U.S. Geological Survey (USGS) GLORIA sidescan images. A small outcrop is also preserved along the southeastern rim (Fig. 4 [in original text]). The deposit is characterized by 10-25 cm, dark-gray dacitic pumice clasts or fiamme (64.0 wt% SiO2) hosted in a lighter-gray, fine ash supported matrix of similar composition (64.9 wt% SiO2). The upper 50-70 m of the ignimbrite is nonwelded and poorly consolidated, but the base is strongly welded and contains flattened fiamme (Fig. 6 [in original text]). Four incremental-heating experiments on whole-rock samples and a phenocryst-free separate of the poorly consolidated facies of the ignimbrite gave a weighted mean 40Ar/39Ar age of 8.4+/-1.5 ka. A U-Th mineral isochron age for this sample (defined by cpx + mt + plag + glass + wr) gave an age of 10.1+/-1.3 ka (Jicha and others, 2005). Thus, we infer that emplacement of this ignimbrite and collapse of the stratovolcano occurred at 9+/-1 ka.\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2017) reports a magnitude of 4.7, bulk eruptive volume of 0.45 cubic km and a dense rock equivalent eruptive volume of 0.188 cubic km for the eruption.","StartYear":-7150,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":1000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Seguam","ParentVolcano":"Seguam","VolcanoID":"ak246","ParentVolcanoID":"ak246"},{"ID":3061,"Name":"Shishaldin 9000 yBP","Description":"From Beget and others (2002): \"Another notable eruption from Shishaldin occurred about 9,000 years ago. This eruption deposited more than 2 meters of pumiceous and scoriaceous tephra near the volcano. Deposits from this eruption are about 3 centimeters thick in Cold Bay, Alaska, about 95 kilometers northeast of the summit vent.\"","StartYear":-7050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":2291,"Name":"Edgecumbe CFE","Description":"From Kosco (1981): \"A pumice eruption associated with the formation of a 1 km caldera marks the end of volcanic activity: this eruption has been radiocarbon dated at 9000 years b.p. (Heusser 1960).\"\r\nFrom Riehle and others (1992): \"A tree stump buried by the topmost of several flow deposits on Kruzof Island (site 7, Fig. 1 [in original text]) closely limits the age of one of the latest pyroclastic eruptions. The outer surface is only incipiently charred (R. Hoblitt, written commun.,1990), so it may have been a lahar that buried the stump. A split of outer rind yielded 9180+/-150 and 9150+/-150 yr B.P. (1-12,218 and 1-12,219; Riehle and Brew, 1984). \r\nFrom Riehle and Brew (1994): \"A thin layer of tephra is separated by silt and peat from underlying tephra layers at several stations on Kruzof Island. The layer is a heterogeneous assemblage of dense volcanic rocks and pumice. The pumice contains 72 percent SiO2 in whole-rock and 74 percent SiO2 in the glass and is slightly more siliceous than samples classified herein as dacite (fig. 65 [ in original text]). Maximum thickness (5 cm) and lapilli size (2 cm) occur southwest of Mount Edgecumbe (82-116, 82-117; fig. 64 [in original text]). The deposit is probably the result of a minor eruption of Mount Edgecumbe or Crater Ridge caldera; the pumice could be accessory material from an earlier unknown deposit incorporated in a largely phreatic eruption.\"\r\n\"We found one tree trunk in a dacitic-pumice-bearing lahar deposit (81-74; fig. 64 [in original text]). The piece was vertical and had a frayed top and a flared base resembling the remains of a root system. We think that the tree was killed and transported by a lahar. A split sample yielded 9,180+/-150 and 9,150+/-150 yr B.P. (I-12, 218; I-12, 219).\"","StartYear":-7050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Edgecumbe","ParentVolcano":"Edgecumbe","VolcanoID":"ak90","ParentVolcanoID":"ak90"},{"ID":3951,"Name":"Great Sitkin 8900 yBP","Description":"From Waythomas and others (2003): \"Lahar deposits in Sitkin Creek valley; Pumice lapilli tephra deposits; Pumiceous pyroclastic-flow deposits north of Sitkin Creek valley.\"","StartYear":-6950,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-6450,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":3561,"Name":"Makushin CFE I","Description":"From Beget and others (2000): \"The oldest deposits of Makushin Volcano that post-date the last ice age record a series of very large eruptions, culminating in the development of a summit caldera (fig. 4 [in original text]). These eruptions began about 8,400 to 8,800 years ago, when a large debris avalanche occurred on the north flank of the volcano and traveled at least 10 kilometers to the coast. On the basis of bathymetry, this avalanche deposit may extend an additional 3 to 5 kilometers off-shore. The upper part of the avalanche deposit is gradational into very coarse grained surge deposits that record a lateral blast apparently coincident with the debris avalanche.\"\r\nFrom Bean (1999): \"Two early Holocene \"caldera forming\" eruptive events, dated at 8050 yr B.P. and ca. 8790 yr B.P. respectively, generated the vast bulk of pyroclastic debris which fill valleys proximal to the volcano. Total erupted volume for early Holocene unconsolidated deposits approaches 10 km 3. The eruptions produced very mobile pyroclastic flows that traveled as far as Dutch Harbor (25 km away) where they buried an ancient Native American culture in more than 30 cm of hot ash and rock fragments.\"\r\n\"A black sintered scoria deposit forms a resistant cap approximately two to four meters thick on lava flows and flat surfaces up to 1000-1500 m elevation on the east and northeast flanks of Makushin Volcano (Fig. 4.23 [in original text]). This unit can be traced to the Lava Ramp where it is not sintered and appears as a scoria fall or flow deposit, and to fans in Makushin Valley where it forms a very resistant sintered unit containing fossil fumaroles. Two radiocarbon samples taken from under this unit have been dated at 8730 and 8710 14 C yr B.P. This black sintered deposit is also present in the summit caldera (Fig 4.23 [in original text]) where it is well exposed at several locations along the eastern caldera rim. The scoria unit here unconformably overlies approximately fifty meters of dipping pink to tan coarse to fine surge deposits and breccias that were most likely deposited during the early phase of the same eruption. The dipping surges are stratigraphically correlated with base surges in Makushin Valley.\"\r\n\"The unit mapped as pyroclastic lag deposits are remnants of pyroclastic valley filling flow deposits. Generally only the highly resistant lower flow unit, a scoria agglutinate to sintered ignimbrite flow unit is still intact, the less resistant overlying members having weathered away.\"\r\n\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2017) reports a magnitude of 6, bulk eruptive volume of 7.5 cubic km and a dense rock equivalent eruptive volume of 3.0 cubic km for the eruption.","StartYear":-6840,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":2541,"Name":"Iskut-Unuk River cones 8730 yBP","Description":"From Hauksdottir and others (1994): \"...overlying basalt flows are dated (14c) at 8730 years (Table 1 [in original text], B.C. Hydro, 1985).\"\r\nFrom Wood and Kienle (1990): \"A lower group of dark-colored alkali basalt flows predates wood that gave a C14 date of 8,780 yr BP.\"","StartYear":-6780,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iskut-Unuk volcanic field","ParentVolcano":"Iskut-Unuk volcanic field","VolcanoID":"ak136","ParentVolcanoID":"ak136"},{"ID":3251,"Name":"Ugashik-Peulik Mafic Crystal Ash","Description":"From Fierstein (2007): \"Peaty soil 30 cm thick plus two ash layers (discussed below) separate the mafic orange fine ash from another compositionally similar tephra (Fig. 13 [in original text]) here called the \"mafic crystal ash\". This older layer is a medium brown crystal-rich ash, 4-5 cm thick in Angle Creek (sample K-2500D), where it is distinct on the cliff face due to sharp upper and lower contacts and relatively coarser grain size (fine to medium crystal sand). The ash is a dark green-orange color, 2-2.5 cm thick, and fine (though still a bit gritty) in Bush Creek (19 km NE, Section K-2675). Because the unit thins and fines eastward, its source is west of the Katmai cluster. From the relatively mafic glass composition (58-62% SiO2), the eruption is inferred not to have been of 1912-magnitude and likely originated from a not-too distant vent. Peulik seems a likely candidate. Peat directly beneath this tephra in Moraine Creek yields a radiocarbon age of 8,500+/-120 14C years. B.P. and in Windy Creek 8,600+/-120 14C years. B.P.\"","StartYear":-6650,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":120,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Ugashik-Peulik","ParentVolcano":"Ugashik-Peulik","VolcanoID":"ak295","ParentVolcanoID":"ak295"},{"ID":1371,"Name":"Akutan Reef Bight Ash","Description":"From Waythomas and others (1998): \"Volcanic ash from Akutan Volcano is typically dark brown or black, and ash of this color first appears in the stratigraphic record about 8500 years ago at Reef Bight...The oldest dated volcanic mudflow (lahar) deposit is exposed at Reef Bight (fig. 3 [in original text]) and is more than 8500 years old. This lahar deposit is the oldest known evidence of Holocene eruptive activity at Akutan Volcano. A younger sequence of deposits at Reef Bight consisting of coarse black ash, pyroclastic flow, and lahar deposits, is evidence for a second eruption or series of eruptions that began soon after 8500 years before present and may be correlative with the formation of the older caldera.\"\r\nFrom Waythomas (1999): \"Dark-brown or black scoriaceous tephras from Akutan Volcano first appear in the stratigraphic record approximately 8500 years B.P. at Reef Bight...The oldest dated volcaniclastic deposit is a noncohesive lahar at Reef Bight that is \u003e8500 years B.P. and is the first evidence of Holocene eruptive activity at Akutan Volcano. A sequence of scoriaceous lapilli tephra. pyroclastic-flow, and noncohesive lahar deposits also at Reef Bight is evidence for a second early Holocene eruptive period that began soon after 8500 years B.P. An undated, noncohesive lahar at Reef Bight documents a possible third early Holocene eruption. The age and location of deposits at Reef Bight suggest that they were generated during eruptions from the \"older\" caldera on Akutan Volcano.\"","StartYear":-6550,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":2881,"Name":"Mageik Thick Gritty Salmon Ash","Description":"From Fierstein (2007): \"The oldest flows from East Mageik (unit \"meo\" of Hildreth and Fierstein 2003) have more degraded surfaces than their younger counterparts, although they are not obviously ice-scoured...Tephra deposits possibly associated with this eruptive episode are three older ash layers identified in the Angle Creek key section: the bluish-grey ash (just below K-2500G: ∼6,000-6,700 14C years B.P.), the thick gritty salmon ash (K-2500E: underlying peat is 8430+/-115 14C years B.P.) and the thick orange-tan ash (K-2500B: ∼9,260 14C years B.P.). Glass shards from the thick gritty salmon ash span a wider SiO2 range (74-78 wt.%) than those from the bluish-grey and the thick orange-tan (74-76 wt.%) ashes, while oxide data for all three ash layers overlap (Fig. 23 [in original text]). Microprobe data for these ash layers are so similar to those from younger East Mageik tephra that I am fairly confident they, too, are from East Mageik. The total eruptive volume of the East Mageik lavas is 5-6 km3, to which the dacitic falls and one small andesitic pyroclastic-flow deposit preserved locally atop \"meo\" add no more than 0.1 km3 (Hildreth and Fierstein 2000). Thus, over a period of ∼7,000 years, the preserved tephra record suggests there may have been at least six eruptive episodes from East Mageik plus one phreatic event, each separated by as little as 100 years to as much as 2,700 years.\"\r\n\"Between the two mafic tephras just described [at the Angle Creek section] are two ash layers. One is a very thin (0.1-0.5-cm) pinkish-tan fine to very fine ash just a few centimeters above the mafic crystal ash. Though its light color stands out in the enveloping black peaty soil, this unit is so thin that it was not collected, and a correlative ash elsewhere has not been identified. The second tephra-a tan to salmon-colored fine to very fine ash-is ∼9 cm thick in Angle Creek (K-2500E, Fig. 3 [in original text]) and is, in turn, a few centimeters above the pinktan ash and 24 cm beneath the mafic orange fine ash. Because it is slightly gritty to the touch (but still very fine; Md\u003c0.6 mm) it is here called the \"thick gritty salmon ash\". Despite its thickness, however, no other correlative ash has yet been identified in any of the other measured sections. Peat directly beneath the tephra yields a radiocarbon age of 8,430+/-115 14C years B.P. (Table 2, Fig. 3 [in original text]). A source at Mount Martin would seem likely, especially one associated with eruption of the Martin lava coulees just upstream, since radiocarbon dates of twigs in soil atop the coulees show the lavas must be older than ∼6,200 14C years B.P. (Fig. 3, Table 2 [in original text]; K-2661A-sx). However, microprobe analyses of Fe-Ti oxides in the tephra are unlike those of the coulees (Fig. 13 [in original text]). Although the youngest stubby lavas high up near the Martin cone do have glass and oxide compositions similar to the tephra, they are too young to correlate with it (since they are younger than the coulees). Thus, because the source was apparently not at Mount Martin, and because the source is inferred to be relatively local (this ash has gritty components and is not all ultra-fine), a source at Mount Mageik is considered most likely. Microprobe data (glass and Fe-Ti oxides) plot similarly to other tephras from Mageik (upper pale tan, lower grey, and ODLF ash layers; Fig. 13 [in original text]) and are, at least, consistent with this tentative conclusion.\"","StartYear":-6480,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":115,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mageik","ParentVolcano":"Mageik","VolcanoID":"ak187","ParentVolcanoID":"ak187"},{"ID":4051,"Name":"Augustine Crooked Creek Tephra","Description":"From Reger and others (1995): \"One of several grayish brown-weathering Holocene tephras in Kenai Lowland that are the products of brief, small eruptions of Cook Inlet volcanoes-and not known to be widely distributed-is the Crooked Creek tephra, which is first recognized and informally named in this study. This tephra is identified in 11 stratigraphic sections (table 2 [in original text]) in a narrow belt from west of Tustumena Lake northeast to the vicinity of Sterling (fig. 4 [in original text]). Correlation within this set of samples is good to excellent (SC=0.93-0.99) (table 5 [in original text]). We know of no correlative tephras in the region, but we speculate (from the distribution and high silica content) that Crooked Creek tephra could have been erupted from Mt. Augustine. The Crooked Creek tephra was deposited between 7,725+/-210 14C yr ago and 8,375+/210 14C yr ago (fig. A25; table 2, C10 and C17 [in original text]). It could possibly be the distal equivalent of tephra layer G, which dates \u003e1,830+/-80 14C yr B.P. and \u003c39,890 14C yr B.P. on Augustine Island (Beget and Kienle, 1992).\"","StartYear":-6425,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":210,"StartQualifierUnit":"Years","EndYear":-5775,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":210,"EndQualifierUnit":"Years","Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":3581,"Name":"Makushin Driftwood Pumice","Description":"The Driftwood Pumice is the youngest of three large explosive eruptions from Makushin volcano @655@@15121@.  The bulk of the deposit fell to the north and northeast of the summit of Makushin and is found in thicknesses of over a meter in Driftwood Valley and Waterfall Valley and ~2 cm in the Dutch Harbor area @655@@13521@. The eruption produced ~0.3-1.6 km^3 bulk pumice and scoria tephra fall deposits (minimum estimate from Lerner and others [2018]@13521@). The yellow pumiceous deposit serves as a distinct marker unit within Makushin Holocene tephra deposits @655@.  Radiocarbon dating by Bean (1999)@655@ and Larsen and others (2020)@15121@ result in a deposit age between 6,400 +/- 20 and 5,070 ± 160 14C yr BP (between 7,417-7,271 and 6,498-6,215 cal yBP).  Bean (1999)@655@ assigns a VEI of ~4.\r\nLerner and others (2018)@13521@ subdivided the Driftwood Pumice into four layers:  three pumiceous layers (units PL, PM, and PU) and a capping ash layer (Mcap).  The lowest pumice layer (PL) is 3-20 cm thick, reversely graded, and composed of well-sorted, brown-beige pumice, ranging in size from 1 to 6 mm in diameter with a mean diameter of ~4 mm. This layer also includes abundant smaller lithic fragments consisting almost entirely of black, dense, vitric material (23 wt% of the layer).  The middle pumiceous layer (PM) is 10-15 cm thick, moderately well-sorted, ungraded, and composed of vitric lapilli and fine blocks ranging in diameter from 3 mm to more than 100 mm with a mean diameter of ~11 mm.  PM has sparse, smaller lithic fragments making up 5 wt% of the layer.  The upper pumiceous layer (PU) is 3-20 cm thick and a darker yellow-brown than the underlying PL and PM layers.  The PU is composed of a mixture of brown-beige pumice (42 wt%), dark gray-black scoria (23 wt%), and an abundance of non-vitric lithics (32 wt%). PU lapilli are poorly sorted and vary in mean grain size (6-14 mm); scoriaceous clasts with a mean diameter of ~12 mm are larger than both the pumiceous and lithic fragments. Within 10 km of Makushin’s summit, scoriaceous bombs in the PU layer are up to 10 cm in the long dimension.  The top ash layer (Mcap) is a dark brown-gray ash (3-12 cm thick) that caps the deposit and is composed of gray-brown glass shards, plagioclase crystals, mafic minerals, and lithic fragments.  The contact of PU and Mcap is irregular with the overlying Mcap ash filling gaps between the uppermost PU clasts. The upper Mcap is commonly reworked and overlain by a soil.\r\nWhole rock geochemical analyses of juvenile material from the Driftwood Pumice range from low-silica dacite to andesite @13521@.  Glass major-oxide geochemistry is found in Bean (1999)@655@, Lerner and others (2018)@13521@, and Larsen and others (2020)@15121@; matrix glass compositions range from dacite to trachydacite.","StartYear":-6400,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":20,"StartQualifierUnit":"Years","EndYear":-3120,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":160,"EndQualifierUnit":"Years","Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":3681,"Name":"Okmok 8250 yBP","Description":"From Miller and Smith (1987): \"Black (1975) reported 14C dating of a \"20-to 30-cm thick\" tephra deposited directly on a cultural horizon near the west end of Umnak Island 70 km from Okmok (Fig. 1 [in original text]). The tephra thickens towards Okmok; Black concluded that it represents a catastrophic eruption of the volcano at about 8250 B.P.\"\r\nFrom Beget and others (2005): \"At least four significant eruptions of mafic scoria (~54 wt. % SiO2; Wong, 2004) occurred during the time period between the older and younger caldera-forming eruptions and these are mainly found to the northeast and south of Okmok caldera. These units are poorly understood, yet contain evidence for explosive interactions between external water and magma, producing phreatomagmatic deposits. The most extensive of these is described in Wong (2004), and consists of thick deposits of scoria and rock fragments deposited to the south and east of the present caldera. In addition, a thin surge bed containing incinerated plant remains occurs between deposits of the first and second caldera-forming eruptions on southern Unalaska Island. This surge, which is associated with a thick tephra-fall deposit and is also locally exposed on the east end of Umnak Island, demonstrates that highly mobile pyroclastic flows capable of traveling across water to distances of 20 kilometers and more from Okmok Volcano can be generated independently of caldera-forming eruptions. Radiocarbon dates from charcoal in the surge suggest it occurred about 8,000 years ago, similar in age to an ash deposit near Nikolski, which was attributed to a large eruption of Okmok (Black, 1974).\"","StartYear":-6300,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Okmok","ParentVolcano":"Okmok","VolcanoID":"ak206","ParentVolcanoID":"ak206"},{"ID":3571,"Name":"Makushin CFE II","Description":"From Beget and others (2000): \"The oldest deposits of Makushin Volcano that post-date the last ice age record a series of very large eruptions, culminating in the development of a summit caldera (fig. 4 [in original text]). These eruptions began about 8,400 to 8,800 years ago, when a large debris avalanche occurred on the north flank of the volcano and traveled at least 10 kilometers to the coast. On the basis of bathymetry, this avalanche deposit may extend an additional 3 to 5 kilometers off-shore. The upper part of the avalanche deposit is gradational into very coarse grained surge deposits that record a lateral blast apparently coincident with the debris avalanche.\"\r\nFrom Bean (1999): \"Two early Holocene \"caldera forming\" eruptive events, dated at 8050 yr B.P. and ca. 8790 yr B.P. respectively, generated the vast bulk of pyroclastic debris which fill valleys proximal to the volcano. Total erupted volume for early Holocene unconsolidated deposits approaches 10 km 3. The eruptions produced very mobile pyroclastic flows that traveled as far as Dutch Harbor (25 km away) where they buried an ancient Native American culture in more than 30 cm of hot ash and rock fragments.\"\r\n\"A distinct, several cm thick, poorly-sorted orange, coarse sandy flow unit lies above the soils. This flow unit is stratigraphically low in section and thought to represent the earliest large Holocene eruptions. It is informally named the earliest caldera forming event (CFE1) unit. The CFE1 is separated from overlying flow deposits by a thin (~2 cm) organic rich soil which locally contains charcoal fragments. Age dates for this deposit average around 8050 14C yr B.P. (Table 6.1 [in original text]). The CFE1 is not present at all localities suggesting a more restricted flow and smaller eruptive event, or poorer preservation than later large events.\"\r\n\"Overlying the lower CFE1 unit is the distinct CFE2 unit. It is orange-red, poorly sorted and massive coarse sand with common pumice, scoria lapilli, and lithics. CFE2 is generally thicker (usually 20-30 cm) than CFE1 but is even thicker in some locations. The base of this unit locally is commonly red and very indurated. At a site near the airport (96MAK23), faint cross-bedding is present and scoria lapilli up to 2.5 cm diameter were found in the deposit (Fig. 4.25 [in original text]). The CFE2 is commonly underlain by several cm of dark gray well-sorted sandy tephras and is less commonly overlain by a thin (~1 cm) of fine orange ash. Several cm of gray ashy silt commonly separate the CFE2 from a thin 2 cm yellow pumice unit containing small glassy lithics. The pumice unit can be found in most distal sites and has been geochemically correlated with proximal deposits of the Driftwood Pumice.\"\r\n\"At site 97MAK14, CFE2 deposits were found overlying till from the only known moraine in the Dutch Harbor area. The moraine is exposed behind a local machine shop in Dutch Harbor, and apparently once stretched across what is today Unalaska Lake. The moraine is most likely latest Pleistocene to earliest Holocene in age.\"\r\nFrom Beget and others (2000): \"Numerous pyroclastic-flow deposits fill valleys on the east, northeast, north, and west of the volcano, and have been dated to about 8,000 to 8,100 years before present (Bean, 1999). The pyroclastic flow deposits are more than 100 meters thick at the head of Makushin Valley and can be traced downvalley 20 kilometers to the shore of Unalaska Bay, where they reach a maximum thickness of 3 meters. Correlative pyroclastic deposits containing incinerated plants occur at Hog Island, 7 kilometers  farther  to  the  east  across  Unalaska  Bay, where they are 1 to 2 meters thick. The summit caldera was produced during the pyroclastic flow eruptions 8,000 to 8,100 years ago.\"","StartYear":-6100,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":80,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":3261,"Name":"Ugashik-Peulik 7890 yBP","Description":"From Fierstein (2007): \"A thin (up to 1 cm) pale orange very fine ash (sample K-2500F) stands out in distinct contrast with the dark silty soil in which it is locally preserved ∼45 cm beneath the \"lower ash rib.\" Better preserved in the lower VTTS, it is as thick as 4.5 cm in Bush Creek, where it is dark greenish-orange and still very fine. In Moraine Creek, too, a 3-cm-thick greenish-orange ash in the same stratigraphic position is likely correlative with this unit, although no microprobe data are in-hand to be sure. Glass data that are available show this tephra is relatively mafic (56-62% SiO2; Fig. 13 [in original text]), and most magnetites are relatively high in MgO, with a distinctive trend similar to that of the upper grey ash. Because both glass and magnetite data are similar to those of the upper grey ash and are distinct from other Martin, Mageik, and Katmai tephra, this ash layer is suspected to have been derived from a source on Mount Peulik. A radiocarbon date on peat beneath the ash in Angle Creek yields 7,890+/-120 14C B.P., and peat beneath the (probably) correlative ash layers in Moraine Creek yields 7,440+/-120 14C B.P. and in Willow Creek 7,700+/-120 14C B.P.\"","StartYear":-5940,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":120,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Ugashik-Peulik","ParentVolcano":"Ugashik-Peulik","VolcanoID":"ak295","ParentVolcanoID":"ak295"},{"ID":3841,"Name":"Peulik Mafic Orange Fine Ash","Description":"From Fierstein (2007): \"A thin (up to 1 cm) pale orange very fine ash (sample K-2500F) stands out in distinct contrast with the dark silty soil in which it is locally preserved ∼45 cm beneath the \"lower ash rib\". Better preserved in the lower VTTS, it is as thick as 4.5 cm in Bush Creek, where it is dark greenish-orange and still very fine. In Moraine Creek, too, a 3-cm-thick greenish-orange ash in the same stratigraphic position is likely correlative with this unit, although no microprobe data are in-hand to be sure. Glass data that are available show this tephra is relatively mafic (56-62% SiO2; Fig.13 [in original text]), and most magnetites are relatively high in MgO, with a distinctive trend similar to that of the upper grey ash. Because both glass and magnetite data are similar to those of the upper grey ash and are distinct from other Martin, Mageik, and Katmai tephra, this ash layer is suspected to have been derived from a source on Mount Peulik. A radiocarbon date on peat beneath the ash in Angle Creek yields 7,890+/-120 14C B.P., and peat beneath the (probably) correlative ash layers in Moraine Creek yields 7,440+/-120 14C B.P. and in Willow Creek 7,700+/-120 14C B.P.\"","StartYear":-5940,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":120,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Peulik","ParentVolcano":"Ugashik-Peulik","VolcanoID":"ak212","ParentVolcanoID":"ak295"},{"ID":4071,"Name":"Augustine ECR-100 Tephra","Description":"From Payne and others (2008):\"The ECR 100 tephra shows greatest similarity to tephra from Augustine Volcano, although correlations are imperfect and the data set very small. The age-depth model places the tephra at ca. 2840 cal yr BP. Little is known about the distribution of tephra from Augustine eruptions prior to ca. AD 200 (Begét and Kienle, 1992; Waitt and Begét, in press). The source of the tephra cannot be reliably determined, although an Augustine eruption is tentatively suggested as the most likely based on available evidence. Limited data for the MTR 190 tephra show some similarity to tephras from Redoubt Volcano. The age-depth model places the layer at ca. 8660 cal yr BP; the closest Redoubt eruption to this date has an uncorrected radiocarbon date of 7730+/-150 14C yr BP (7050-6250 cal yr BP). This eruption may be the most likely candidate for the source of this tephra but uncertainties remain.\"","StartYear":-5780,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":150,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":3391,"Name":"Tanaga 7700 yBP","Description":"From Jicha and others (2012): \"A basaltic andesite lava on the northern flank of Tanaga, near the shoreline, gave an imprecise age of 7.7+/-12.1 ka, thereby confirming its young age (Table 1 [in original text]).","StartYear":-5750,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":12100,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Tanaga","ParentVolcano":"Tanaga","VolcanoID":"ak280","ParentVolcanoID":"ak280"},{"ID":3941,"Name":"Great Sitkin 7600 yBP","Description":"From Waythomas and others (2003): \"Pumice and lithic lapilli tephra deposit (Main ash?).\"\r\nNote that Waythomas and others (2001) suggest that Moffett is the source of the Main ash. Unclear whether this ash is indeed the Main ash (i.e. erupted by Moffett and deposited on Great Sitkin), or an ash erupted by Great Sitkin and incorrectly thought to be the Main ash.","StartYear":-5650,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-5350,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":3031,"Name":"Seguam 7500 yBP","Description":"From Jicha and Singer (2006): \"An older, tundra-covered 0.08 km cubed rhyolite flow (rcv) crops out to the west of the rcc cone. This plagioclase-phyric lava dips 20 degrees to the northwest and is strongly flow banded with alternating layers of red rubble and black, glassy rhyolite. Three incremental-heating experiments from the glassy rhyolite yielded a weighted mean plateau age of 7.5+/-2.0 ka (Table 1; Fig. 5 [in original text]).\"","StartYear":-5550,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":2000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Seguam","ParentVolcano":"Seguam","VolcanoID":"ak246","ParentVolcanoID":"ak246"},{"ID":2421,"Name":"Hayes Oshetna Tephra","Description":"From Dixon and Smith (1990): \"The Oshetna tephra consists of a uniform layer of light brownish gray (2.5Y 6/2) sandy silt typically 3 to 5 cm thick although a maximum thickness of 8 cm was observed. Microscopically the Oshetna tephra is characterized by the presence of quartz, feldspar, glass shards, blue-green hornblende, and orthopyroxene.\"\r\nFrom Davies and others (2016): \"The Oshetna tephra has been reported at several sites within central Alaska, particularly in association with archaeological sites in the Susitna valley (e.g. Dixon, 1985). While its source was not identified, it has recently been suggested that it may originate from the Hayes volcano (Wallace and others, 2014).\"\r\nFrom Wallace and others (2015): \"The Oshetna tephra, informally named by Child and other (1998) for the stream valley in which it was first identified during cultural resource investigations conducted from 1979-85, is widespread in the Susitna River valley in south-central Alaska (fig. 1A [in original text]; J.E. Dixon and others, written commun(s)., 1985). The Oshetna tephra is 3-5 cm thick in this region, and is attributed to Hayes Volcano based on similarities in mineralogy and major-element glass composition to Hayes Volcano tephras. The Oshetna tephra was erupted 5,960-5,790 14C yr B.P. (Child and others, 1998), which makes it older than tephra set H at the Hayes River outcrop. Numerous additional radiocarbon analyses from J.E. Dixon and others (written commun(s)., 1985) corroborate this age. Glass analyses for pumice from the Hayes River ignimbrite do not match glass data for the Oshetna tephra, which have lower SiO2 and K2O, and higher CaO, MgO, and TiO2 than Hayes River ignimbrite glass (fig. 10 [in original text]). Similar amounts of amphibole and biotite in the Oshetna tephra and the rhyodacite clasts from Unit II at the Hayes River outcrop are suggestive of a possible correlation, though we do not have glass analyses of the rhyodacite to test this hypothesis.\"\r\nFrom Mulliken (2016): \"Glass geochemical analyses indicate that the Oshetna tephra is heterogeneous with at least four populations of volcanic glass. Previous analyses of the Oshetna tephra, however, have only identified two population of volcanic glass in the deposit (Child and others 1998; Dilley 1988) (Tables 2.1 and 2.2 [in original text]). Because the source, or sources, of the volcanic glass shards comprising the Oshetna tephra are unknown, it is difficult to evaluate its deposit in terms of the number of volcanic events represented. The Oshetna could be a product of Hayes Volcano, based on the proximity and thickness of the deposit; however, the deposit lacks biotite (Romick and Thorson 1983), which is a mineral characteristic to Hayes Volcano. Therefore, another possibility is that the deposit is reworked and representative of multiple tephra depositional events from different volcanoes. Ashfalls from nearby Cook Inlet volcanoes as recorded in lacustrine cores (de Fontaine and others 2007; Schiff and others 2008) suggest that numerous tephra deposits could be present in the mSRV. Redoubt, Augustine, Iliamna, and Spurr volcanoes could have deposited Holocene aged tephra in the mSRV and future correlation efforts will aid in understanding the Oshetna deposit.\"","StartYear":-5140,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":30,"StartQualifierUnit":"Years","EndYear":-3900,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":25,"EndQualifierUnit":"Years","Volcano":"Hayes","ParentVolcano":"Hayes","VolcanoID":"ak116","ParentVolcanoID":"ak116"},{"ID":3101,"Name":"Spurr 7060 yBP","Description":"From Nye and Turner (1990): \"Riehle (1985) reports a minimum age of older Mt. Spurr tephra of slightly older than 7000 radiocarbon years...\"","StartYear":-5110,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":120,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Spurr","ParentVolcano":"Spurr","VolcanoID":"ak260","ParentVolcanoID":"ak260"},{"ID":2461,"Name":"Iliamna 7000 yBP","Description":"From Waythomas and others (1999): \"The second of the two fine-grained ash layers found on the Kenai Peninsula is geochemically similar to the proximal lapilli tephra and dates to about 7,000 yr B.P. This ash bed is evidence for an older plinian(?) eruption of Iliamna Volcano but so far no associated volcanic deposits have been identified on the proximal flanks of the volcano.\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2017) reports a magnitude of 4.000, bulk eruptive volume of 0.100 cubic km and a dense rock equivalent eruptive volume of 0.040 cubic km for the eruption.","StartYear":-5050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":1211,"Name":"Aniakchak Black Nose Pumice","Description":"From Bacon and others (2014): \"Subsequent to Aniakchak I, Plinian eruptions ca. 7,000 14C yr B.P. from a vent northeast of the edifice summit produced the Black Nose Pumice, consisting of a lower unit of rhyodacite lava, pumice fall, and intraplinian welded ignimbrite and an upper unit of dacite pumice fall and northeast flank lava flow.\"\r\n\"A comparatively thin tephra bed (VanderHoek and Myron, 2004, sample ANI 99-L) beneath the principal fall deposit at Cabin Bluff (ANI 99-K) contains glass and Fe-Ti oxides compositionally similar to those of the principal deposit as well as another population of glass that is more evolved and oxides that have somewhat different compositions (appendix A, tables A1 and A2 [in original text]). We tentatively interpret the lower bed as representing one or more eruptions of Aniakchak volcano precursory to the Black Nose Pumice eruptions.\"\r\n\"Following Dreher’s (2002, p. 17) description of the Black Nose Pumice and prior informal usage of this term, we apply the name to dacite and rhyodacite Plinian pumice fall deposits and intercalated (intraplinian) welded rhyodacite ignimbrite north of The Gates and to correlative deposits elsewhere near the caldera rim. The unit is named for exposures 2.5 km south of The Gates at Black Nose, although a more accessible and probably more complete section is present north of The Gates. An ~2,000-m square patch of apparent fall deposit is preserved on a northeast-trending spur at ~1,800 ft (550 m) asl south of the Aniakchak River immediately east of The Gates, which indicates that a deeply incised valley headed just east of the present caldera rim at the time of the Black Nose eruptions. Similarly, a prominent 1,500 ft (460 m) asl bench ~1-2 km east-northeast of The Gates appears to be capped by Black Nose Pumice. Other remnants of Black Nose Pumice may be present on the ~400 x 700 m bench at ~2,300-ft (700 m) elevation south of The Gates. Black Nose Pumice also may be present below younger deposits on the north and west caldera rim. North of The Gates, Black Nose Pumice dips gently towards the caldera and conformably overlies 1 cm of gray ash and 1 cm of brown ash that rest upon the eroded surface of the previously described unconsolidated dacite pyroclastic deposits. The Black Nose Pumice is overlain by Aniakchak II lithic breccia. The Black Nose Pumice is subdivided into lower and upper subunits (figs. 5B and 8 [in original text]).\"\r\n\"The well-sorted beds of the lower Black Nose Pumice consist of highly inflated crystal-poor buff-colored pumice that is rhyodacite in composition. The pumice is chemically less evolved and lacks the hornblende phenocrysts that are present in Aniakchak II rhyodacite pumice (Dreher, 2002). Maximum pumice clast size is ~30 cm. Many clasts have pink interiors and are fractured so that they fall apart when removed from the outcrop. The unit is ~8-10 m thick north of The Gates.\"\r\n\"Welded ignimbrite occurs within the lower Black Nose Pumice north of The Gates ~2 m below the top of the lower Black Nose Pumice fall (figs. 5B, 8A, 8C, and 8D [in original text]). About 1-2 m thick at the locality shown in figure 8D [in original text], the ignimbrite pinches out south towards The Gates and thickens to the north to at least 10 m in topographic lows...The ignimbrite likely represents collapse of the Plinian eruption column, probably owing to vent widening and increase in eruption rate as deduced for the similar Wineglass Welded Tuff at Crater Lake, Oregon (Kamata and others, 1993).\"\r\n\"The age of the lower Black Nose Pumice is constrained by tephrochronology. A 45-cm-thick bed of relatively coarse silicic pumice ~40 km southeast of the caldera near Aniakchak Bay (fig. 1 in original text) was described by VanderHoek and Myron (2004, their figures 7, 8; Cabin Bluff section, ANI 99-K)...Peat from beneath the Cabin Bluff pumice bed yielded a radio-carbon age of 7,350+/-70 yr B.P., whereas soil beneath the same bed 600 m distant gave 6,760+/-60 yr B.P. (table 1 [in original text]; VanderHoek and Myron, 2004; VanderHoek, 2009), leading us to suggest an age of ca. 7,000 yr B.P. for the lower Black Nose Pumice.\"\r\n\"The upper Black Nose Pumice is a Plinian fall deposit that conformably overlies the lower Black Nose Pumice. As large as 40 cm, clasts of brown pumice are silicic dacite, slightly less evolved than the underlying ignimbrite and lower Black Nose Pumice. This pumice has greater phenocryst content than the lower unit (Dreher, 2002). The well-sorted beds are variably oxidized and incipiently welded. Basal upper Black Nose Pumice fall is partly welded and forms a dark-gray band in caldera rim exposures. This nearly uniform-thickness band and the underlying variable-thickness ignimbrite, separated by ~2 m of buff-colored pumice fall, make a distinctive pair of dark-gray stripes across exposures near the rim of the northeast quadrant of the caldera (figs. 8A and 8C [in original text]). The preserved thickness of upper Black Nose Pumice north of The Gates is as much as ~15 m but varies considerably, implying modification during a significant period of erosion. The deposit is overlain by Aniakchak II lithic breccia.\"\r\n\"The distribution of upper Black Nose Pumice and any distal correlations have yet to be established, though the thickness, composition, and coarseness of the deposit at the caldera rim imply wide dispersal downwind. Analyzed dacite pumice from a fall deposit beneath Aniakchak II ignimbrite in lower Reindeer Creek (fig. 4 [in original text], near west edge), sampled by Dreher (2002; sample 98AC70D), has unique composition but is closest to basal upper Black Nose Pumice.\"","StartYear":-5050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-1550,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":2991,"Name":"Moffett Intermediate Ash","Description":"Waythomas and others (2003) tentatively identify Moffett Volcano as the source of the Intermediate Ash, observed on Adak Island and also called AD-4 by Kiriyanov and Miller (1997). \r\nFrom Kiriyanov and Miller (1997): \"AD-4 ash is 4-8 cm thick and consists of pumice gravel and lapilli with a maximum size of 3 cm, small amounts of gray clay- and silt-size materials and fine-grained sand, and a large amount of rock fragments 0.5-0.8 cm in size. The coarser material is concentrated in the middle of the ash layer. Distinctive features of this ash are a considerably large amount of rock debris (13%), absence of pyroxenes, and a very small content of green and brown hornblendes (1-2%). The inferred age of the ash is 4500-4600 14C years (Table 1 [in original text]).\"\r\nFrom Okuno and others (2012): \"The lntermediate tephra-fall deposit consists of pumice and lithic fragments with a cross-laminated ash bed. It is 43cm thick and contains a large amount of dense lithics with a maximum size (ML) of 3.8cm.\"\r\nFrom Waythomas and others (2001): \"A thick lapilli tephra deposit about the same age as the Intermediate Ash is present at locality 00CW06 northeast of Kanaga Volcano (fig. 9 [in original text]) but is not recognized elsewhere on Kanaga Island. Radiocarbon ages associated with Kanaga Island tephra T7 match those of the Sandwich Ash (fig. 13 [in original text]); however, the T7 deposits consist of massive sand-size felsic tephra with granule-size juvenile lapilli at the base (sec. 99CW75, fig. 9 [in original text]) or a single thin lapilli bed (sec. 99CW83, fig. 9 [in original text]) and do not exhibit the sequence massive gray fine ash/oxidized granule lapilli/massive gray fine ash that characterizes the Sandwich Ash on Adak Island. Thus, we are uncertain whether tephra T7 and the Sandwich ash are the same tephra deposit...\"","StartYear":-5010,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":100,"StartQualifierUnit":"Years","EndYear":-2510,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":180,"EndQualifierUnit":"Years","Volcano":"Moffett","ParentVolcano":"Moffett","VolcanoID":"ak192","ParentVolcanoID":"ak192"},{"ID":4481,"Name":"Semisopochnoi CFE","Description":"From Coombs and others (2017): \"The earliest and most substantial Holocene deposit  on the island is a widespread ignimbrite, produced during the latest caldera-forming eruption.\r\nSemisopochnoi caldera covers approximately 43 square km and has walls that vary in prominence. \r\nThe pyroclastic-flow deposit, or ignimbrite, that was ejected during the caldera-forming eruption covers large parts of Semisopochnoi Island, and it can be identified by its fairly flat but incised morphology where it has been covered by younger tephra.\r\nThe stratigraphy of the ignimbrite of the caldera-forming eruption varies considerably by sector and distance from the caldera. In several places, a several-meter-thick tephra-soil complex mantles the deposit and limits its exposure. Despite stratigraphic variations, the general depositional sequence typically consists of a brick-red, oxidized, and lithic-rich top unit that is as much as several meters thick. Many tephra sections bottom out on this unit, which is indurated in most exposures. The lithic-rich top overlies the main body of the ignimbrite, which is typically massive, poorly sorted, and rich in tan-to-black, variably vesicular pumiceous clasts. \r\nThe ignimbrite is variably welded and (or) indurated. Where exposed near the south and east caldera walls, a welded horizon is typically as much as several meters thick, dark gray to black, variably oxidized, and fairly well indurated. Clasts in the welded parts are dense to moderately vesicular and contain striking 2- to 3-mm-diameter plagioclase phenocrysts. This subunit, which forms resistant bands in outcrop, is probably the rock type mapped by Coats (1959) as unit Qbt, which he described as basaltic tuff breccia with minor basaltic flows. Along the southern caldera margin, the welded band is 1-3 m thick, whereas east of Fenner Lake it is \u003e10 m thick.\r\nThe exact location of the vent for this violent explosive eruption is unknown but almost certainly lies within the area of the current caldera. The initial strata deposited by this eruption evidently are not exposed, and so it is unknown whether the eruption began with a Plinian fall, although that is a likely supposition on a comparative basis with similar eruptions. The subsequent ignimbrite commonly is partly welded near the vent, suggesting that it may have been emplaced by pyroclastic flows fed by a collapsed eruption column(s) issuing at high mass-eruption rates.\r\nOn the basis of our tentative age assignment, the Semisopochnoi ignimbrite should be found below the intermediate tephra and above the main tephra on Adak Island.\"\r\nFrom Derkachev and others (2018): \"The ~ 12.2 ka SR2 tephra forms a visible layer in the sediments on the Shirshov Ridge and at the northeastern margin of the Aleutian basin (Figs. 1, 2,and 3). Its thickness varies from 2 to 4 cm.\r\nThe extent and volume of the SR2 tephra, and consequently the magnitude of the parent eruption, can now bpreliminary constrained from these data. The dispersal axis was directed NNW from the source (Fig.1) [in text]. Based on the known thicknesses of the SR2 tephra in all studied cores, we can here draft a preliminary tephra dispersal area (Fig.1 [in text]; Online Resource 5). The sites on the Shirshov Ridge are located close to each other and have a median tephra thickness of 3 cm. These sites, together with sites Lv63-30, -22, and -23 located at the northeastern margin of the Aleutian basin (Fig. 1) [in text], permit us to delineate a 2-cm isopach as a minimum concave line bounding all of these sites. The area within the 2-cm isopach is 767,400 km2, so that by applying the single-isopach approach (Legros 2000) we obtain a minimum ash-fall volume of 54 km3. This corresponds to a volcanic explosivity index (VEI) six (Newhall and Self 1982). Assuming an ash density of 0.6 g/cm3 (Kutterolf et al. 2008b), we obtain SR2 tephra mass of 3.2 × 104 Mt, and aDRE volume of 12 km3. This corresponds to an eruption magnitude 6.5 (Pyle 1995; Mason et al. 2004). These are minimal estimates as they are based on only a few thickness measurements for SR2 tephra, and our calculations do not include the volume of the caldera fill or of ignimbrite dispersed beyond the caldera.\r\nBased on the estimated size and geochemical similarity to the Semisopochnoi ignimbrite, we suggest that the SR2 tephra was a product of the caldera-forming eruption. Our age estimate of ~ 12.2 ka, as well as the stratigraphic position of the SR2 tephra within the Younger Dryas sediments, do not agree with a preliminary age estimate of 7.7-7.8 ka suggested by Coombs et al. (2018) for this ignimbrite. This discrepancy needs further investigation. At the same time, we do not observe any younger tephra of SR2 (and ignimbrite) composition in any of our cores. As a result, two closely spaced different and large eruptions from Semisopochnoi seem unlikely. The SR2 tephra is widely dispersed in the Aleutian basin, and can serve as a marker for the Younger Dryas climate interval.\"","StartYear":-4970,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":60,"StartQualifierUnit":"Years","EndYear":-3050,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":50,"EndQualifierUnit":"Years","Volcano":"Semisopochnoi","ParentVolcano":"Semisopochnoi","VolcanoID":"ak248","ParentVolcanoID":"ak248"},{"ID":2551,"Name":"Iskut-Unuk River cones 6800 yBP","Description":"From Hauksdottir and others (1994): \"Three cinder cones are identified (Fig. 2 [in original text]). The youngest cone lies to the south and appears to have fed the two youngest flows. It appears to have repeatedly erupted lava which dammed both Tom MacKay and Forrest Kerr creeks (B.C. Hydro, 1985). This inference is based on 14c dating of plant remains in lake sediments associated with these ephemeral dams. These age determinations (Table 1 [in original text], B.C. Hydro, 1985; Read and others, 1989) suggest lava effusion occurred 3800, 5600 and 6500-6800 years ago; the Iskut River Canyon was eroded to its present configuration in the last 3600 to 3800 years (B.C. Hydro, 1985).\"","StartYear":-4850,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-4550,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iskut-Unuk volcanic field","ParentVolcano":"Iskut-Unuk volcanic field","VolcanoID":"ak136","ParentVolcanoID":"ak136"},{"ID":2671,"Name":"Kanaga T3","Description":"From Waythomas and others (2001): \"Groups of tephra deposits so defined indicate that at least 11 eruptions of Kanaga Volcano have occurred since about 11 ka. Most of these eruptions were probably sub-Plinian to Plinian, producing moderately vesicular dacitic pumice lapilli tephra deposits ranging in thickness from a few centimeters to more than 1 m (table 2 [in original text]).\"\r\n\"Tan, loamy pumice-lapilli fall deposit.\"","StartYear":-4846,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-4549,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kanaga","ParentVolcano":"Kanaga","VolcanoID":"ak144","ParentVolcanoID":"ak144"},{"ID":2981,"Name":"Moffett Main Ash","Description":"Waythomas and others (2003) tentatively identify Moffett Volcano as the source of the Main Ash, observed on Adak Island and also called AD-5 by Kiriyanov and Miller (1997). \r\nFrom Okuno and others (2012): \"The Main tephra-fall deposit covers multiple tephra-soil complexes (thickness = 14cm) of multiple, fine, thin tephra and soil (Waythomas and others 2001) and glacial till deposits. The Main tephra-fall deposit is 30cm thick and consists of coarse pumice (maximum pumice size, MP= 1.5cm) and a consolidated ash layer as thick as 5cm in the upper part.\"\r\nFrom Waythomas and others (2001): \"The most conspicuous tephra deposit on Adak Island, the Main Ash, has long been regarded as the pyroclastic-fall deposit associated with the caldera-forming eruption that destroyed ancestral Mount Kanaton (Coats, 1956; Black, 1980). However, none of the dated tephra deposits on Kanaga Island matches the radiocarbon ages associated with the Main Ash (fig. 13 [in original text]).\"","StartYear":-4745,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":45,"StartQualifierUnit":"Years","EndYear":-6360,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":265,"EndQualifierUnit":"Years","Volcano":"Moffett","ParentVolcano":"Moffett","VolcanoID":"ak192","ParentVolcanoID":"ak192"},{"ID":3931,"Name":"Great Sitkin 6600 yBP","Description":"From Waythomas and others (2003): \"Pumice lapilli tephra deposit.\"","StartYear":-4650,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-3950,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":1861,"Name":"Augustine Shuyak Island Ash","Description":"From Waitt and Beget (2009): \"On Shuyak Island 110 km southeast of Augustine (fig. 1A [in original text]), two fall tephras of Augustine chemical provenance (probe analysis of glass by J.R. Riehle and C.E. Meyer) date between about 6,460 and 5,020 yr B.P.\"","StartYear":-4510,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":30,"StartQualifierUnit":"Years","EndYear":-3380,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":30,"EndQualifierUnit":"Years","Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":2621,"Name":"Kaguyak 6400 yBP","Description":"From Fierstein and Hildreth (2008): \"A generally unstratified, coarse, grey fragmental deposit forms a Holocene apron distributed west and northeast around Kaguyak caldera (Fig. 3 [in original text]). As shown in photo/sketch Figs. 4, 8, and 10 [in original text], the deposit thinly laps onto margins of the Eastern, Southern, and Northern Edifices. Both the northeast and west caldera walls are constructed of this diamicton; there would be no caldera lake if the deposit were not there. It fills what were low saddles between existing edifices, filling what were apparent drainages (WNW and NE) between the precaldera dome clusters. There is no evidence that this breccia ever covered the peaks or outer flanks of either the Northern or Eastern Edifices, and no evidence that it traveled far from source. Only when funneled into the Big River did it go farther than ~3 km. Three radiocarbon dates (locations along Big River marked with red Xs on Fig. 16 [in original text])-two on organic soil from two locations on top of the breccia and one on charred twigs found in the deposit-yield essentially identical results: respectively, 6010+/-100; 6010+/-110, and 6010+/-160 14C yrs B.P. (Fierstein 2007). In agreement, a 40Ar/39Ar date for a lava block within the breccia yields 6.4+/-5.0 ka (Table 1 [in original text]).\"\r\n\"Similar in all exposures around the caldera, the grey-brown, gritty matrix includes almost no clay and is seriate with the rest of the deposit, which includes angular to subangular lava blocks, commonly up to 4 m and as big as 8 m. All blocks are largely glassy, fresh to oxidized (none hydrothermally altered), dense to micropumiceous lava; there is no pumice in this deposit. Young and unglaciated, the breccia apron is cut radially by V-shaped gullies that project skyward at the caldera rim (Fig. 13 [in original text]), indicating that the gullies were beheaded by caldera collapse and thus predate it.\"\r\n\"[Fierstein and Hildreth (2008)] infer that the Big Breccia deposit resulted from catastrophic disruption and collapse of what was probably a new dome extruding close to the position of present-day Dome 2015.\"","StartYear":-4450,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":500,"StartQualifierUnit":"Years","EndYear":-4060,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":160,"EndQualifierUnit":"Years","Volcano":"Kaguyak","ParentVolcano":"Kaguyak","VolcanoID":"ak143","ParentVolcanoID":"ak143"},{"ID":2211,"Name":"Mt Churchill MTR-146 Tephra","Description":"From Preece and others (2014): \"...cores in southeastern Alaska contain two other tephra beds with compositions similar to WRA. These are the ca. 300 yr B.P. (ca. A.D. 1650) Lena ash preserved at sites A and B (Fig. 1 [in original text]) and the ca. 6330 cal yr B.P. MTR-146 ash preserved at site B (Fig. 1 [in original text]) (Payne and others, 2008).\"\r\nFrom Payne and others (2008): \"There is also similarity in the composition of CHP 184, MTR 146, and LNA 100 tephras, although considerable differences in their probable age. Similarity coefficients of these tephras with WRA reference data are also high; SCs exceed 0.95 with at least one of the established data sets (Table 4 [in original text]). Similarity coefficients are most convincing with the LNA 100 tephra, with five of the values exceeding 0.95, and least convincing with the CHP 184 tephra, with only one of the SCs exceeding 0.95. A ternary diagram comparing CHP 184, MTR 146, LNA 100, SPM 26, LNA 39, and ECR 32 with the White River Ash reference data shows a convincing overlap (Fig. 3 [in original text]), providing evidence that these tephras are the WRA or have the same source. By contrast, SCs with many other tephras compared do not exceed 0.95.\"\r\n \"The ECR 162 tephra has been dated to 5030-5300 cal yr BP (SUERC-5917; Table 6). ECR 100, MTR 146, and MTR 190 tephras were not directly dated. Age-depth interpolation suggests that the ECR 100 tephra was deposited ca. 2840 cal yr BP, the MTR 146 tephra ca. 6300 cal yr BP, and the MTR 190 tephra ca. 8660 cal yr BP.\"","StartYear":-4350,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Churchill, Mt","ParentVolcano":"Churchill, Mt","VolcanoID":"ak50","ParentVolcanoID":"ak50"},{"ID":1391,"Name":"Akutan Harbor Tephra","Description":"From Waythomas and others (1998): \"Volcanic ash from Akutan Volcano is typically dark brown or black, and ash of this color...appears in the stratigraphic record...about 6100 years ago in the Akutan Harbor area.\"","StartYear":-4150,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":3041,"Name":"Seguam 6000 yBP","Description":"From Jicha and Singer: \"The western flank of the cone and southern margin of the rcv flow are overlain by a small, gray, vitrophyric lava flow (srf), the most evolved on the island (71.4 wt% SiO2) (Table 2; Fig. 4 [in original text]). The 40Ar/39Ar geochronology was unsuccessful on this material, but whole-rock, plagioclase, clinopyroxene, magnetite, and glass yielded a U-Th isochron age of 6+/-4 ka (Jicha and others, 2005).\"","StartYear":-4050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":4000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Seguam","ParentVolcano":"Seguam","VolcanoID":"ak246","ParentVolcanoID":"ak246"},{"ID":3111,"Name":"Spurr 6000 yBP","Description":"From Nye and Turner (1990): \"Riehle (1985) reports a minimum age of basal Crater Peak (including proto-Crater Peak) tephra of 6000 years. The Mt. Spurr and the Crater Peak/proto-Crater Peak complex were, in part, coeruptive.\"\r\nFrom Riehle (1985): \"The oldest tephra layers assigned to the Crater Peak vent are loosely bounded by the available data to a middle Holocene age (sites 13 and 14; Fig. 11; site 20, Fig.12 [in original text]).\"","StartYear":-4050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Spurr","ParentVolcano":"Spurr","VolcanoID":"ak260","ParentVolcanoID":"ak260"},{"ID":4491,"Name":"Kanaga T3","Description":"From Coombs and others (2017): \"Although thorough tephrostratigraphic work has not been conducted on other Aleutian islands to the east, such as Tanaga or Gareloi, a study of Holocene volcanic stratigraphy shows a ~6,000 14C yr B.P. silt- to sand-sized tephra called T3, located 220 km to the east on Kanaga that is a possible candidate for a Semisopochnoi source (Waythomas and others, 2003).\"","StartYear":-4050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Semisopochnoi","ParentVolcano":"Semisopochnoi","VolcanoID":"ak248","ParentVolcanoID":"ak248"},{"ID":1401,"Name":"Akutan Hot Springs Valley Lahar","Description":"From Waythomas and others (1998): \"A slightly clay-rich lahar in Hot Springs Valley (fig. 3 [in original text]) probably formed from a minor collapse of the volcano flank, perhaps in the area of an active  fumarole field in the upper part of the valley. No obvious scarp is present. Although not exposed at the coast, this lahar probably reached Hot Springs Bay about 6000 years ago.\"\r\nFrom Waythomas (1999): \"A cohesive lahar in Hot Springs valley formed from a minor flank collapse of water-saturated, altered rock debris, probably in the area of an active fumarole field in the upper part of the valley. No obvious scarp is present. Although not exposed at the coast, this lahar probably reached Hot Springs Bay approximately 6000 years B.P. Because the lahar deposits in Hot Springs Bay valley originated from a localized slope failure, they are not likely related to any eruption of Akutan Volcano.\"","StartYear":-4050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":2891,"Name":"Mageik Bluish Grey Ash","Description":"From Fierstein (2007): \"The oldest flows from East Mageik (unit \"meo\" of Hildreth and Fierstein 2003) have more degraded surfaces than their younger counterparts, although they are not obviously ice-scoured...Tephra deposits possibly associated with this eruptive episode are three older ash layers identified in the Angle Creek key section: the bluish-grey ash (just below K-2500G: ∼6,000-6,700 14C years B.P.), the thick gritty salmon ash (K-2500E: underlying peat is 8430+/-115 14C years B.P.) and the thick orange-tan ash (K-2500B: ∼9,260 14C years B.P.). Glass shards from the thick gritty salmon ash span a wider SiO2 range (74-78 wt.%) than those from the bluish-grey and the thick orange-tan (74-76 wt.%) ashes, while oxide data for all three ash layers overlap (Fig. 23 [in original text]). Microprobe data for these ash layers are so similar to those from younger East Mageik tephra that I am fairly confident they, too, are from East Mageik. The total eruptive volume of the East Mageik lavas is 5-6 km3, to which the dacitic falls and one small andesitic pyroclastic-flow deposit preserved locally atop \"meo\" add no more than 0.1 km3 (Hildreth and Fierstein 2000). Thus, over a period of ∼7,000 years, the preserved tephra record suggests there may have been at least six eruptive episodes from East Mageik plus one phreatic event, each separated by as little as 100 years to as much as 2,700 years.\"\r\n\"Only 1 to 3 cm below the lower ash rib [at the Angle Creek section] is a laterally discontinuous but commonly preserved light grey fine ash. Although thin here (1-3 mm) and not collected, this layer is tentatively correlated with a bluish-grey fine ash found widely in the Windy Creek drainage (4 cm thick; Fig. 3 [in original text]), on the east side of the lower VTTS (3 cm thick, K-2590), and nearby in Willow Creek (3.5 cm thick, K- 2588; Fig. 2 [in original text]). Stratigraphic position strongly suggests this ash is also found in Margot Creek (1 cm thick), in Martin Creek (3 cm thick, K-2339A; Fig. 2 [in original text]), is the basal ash in a section near the east margin of the VTTS at the foot of Mt. Griggs (4 to 7 cm thick, K-2345), and is a normally graded 4-cm fall in upper Angle Creek, K-2072). Microprobe data for three of these samples (lower VTTS and Martin Creek) shows they not only correlate well with one another, but also with other tephras from Mount Mageik (younger ones: lower grey and ODLF, and older ones: thick gritty salmon, and thick orange-tan; Figs. 3, 13 [in original text]). Thickness, grain size, stratigraphy, and limited microprobe data are all consistent with this ash originating from East Mageik, with a northerly to NNE dispersal. Radiocarbon dates on loess and organic-richer soils beneath the tephra yield 5,800+/-50 (head of Angle Creek, K-2072), 6,420+/-240 (Windy Creek, K-2544), 5,670+/-170 (Margot Creek, K-2513G), and 6,720+/-140 14C years B.P. (see Table 2 [in original text]).\"","StartYear":-3960,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":80,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mageik","ParentVolcano":"Mageik","VolcanoID":"ak187","ParentVolcanoID":"ak187"},{"ID":2801,"Name":"Koniuji 5800 yBP","Description":"From Jicha (2009): \"One of the numerous thin basaltic andesitic flows that form a steep cliff of the western shoreline gave a 40Ar/39Ar plateau age of 5.8+/-3.1 ka (Table 1 [in original text]).\"\r\n\"Following subaerial basaltic andesitic effusions at ~15 ka, a series of thin basaltic andesitic flows formed the western and central sector of the island at ~5.8 ka.\"","StartYear":-3850,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":3100,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Koniuji","ParentVolcano":"Koniuji","VolcanoID":"ak168","ParentVolcanoID":"ak168"},{"ID":2631,"Name":"Kaguyak CFE","Description":"From Miller and Smith (1987): \"Kaguyak crater is a small (2.6 km diameter), little-known, lake-filled, circular caldera in the northeast corner of the [Katmai National] park (Fig. 1 [in original text]). Nonwelded ash-flow tuffs are confined to within 7 km of the caldera and do not appear to have been particularly mobile. The ash flows filled previously glaciated valleys...\"\r\nFrom Fierstein (2007): \"A dacitic Plinian eruption blanketed at least 120 km2 with a moderate-sized ignimbrite during the caldera-forming eruption at Kaguyak, 70 km NE of Mount Katmai. Although the accompanying coarse plinian fallout is not widely preserved (and may never have been widely dispersed), the coignimbrite ash elutriated during emplacement of the ignimbrite is a widespread marker bed in the region (see discussion of \"Bright orange fine ash\" [in original text]). Microprobe analyses of magnetites from this ejecta are distinctively low TiO2, and glass shards are distinctively low in K2O and high in CaO at 75.5-78.5% SiO2, which clearly distinguishes them from ejecta of all other Katmai volcanoes (Figs. 5, 13 [in original text]). Many radiocarbon dates from locations between Windy Creek and Kaguyak caldera constrain the collapse event to 5,800 14C years B.P.\"\r\n\"Eruption volumes are poorly constrained for this caldera-forming event due to patchy preservation and/or exposure...Deposits within 10 km of vent are all pumice falls, shed from (what was likely) a (sub)plinian column. Beyond 25 km from vent, the fallout is a fine-grained bright orange layer that is largely coignimbrite ash. Thickness data used in volume calculations (after Fierstein and Nathenson, 1992) yield an estimate of ~0.3 km3 within the moderately constrained 9-cm isopach and another 0.4 km3 within the less well constrained 3-cm isopach. Although distal ash distribution is poorly constrained, we draw tentative isopachs to 1.5 cm that include the well-correlated tephra on the Kenai Peninsula and the less well correlated tephra on Afognak Island and Kukak Bay (Fig. 1; see Section 8.1.3 [in original text]). This could add as much as 2.8 km3 to the fall volume, for a total tephra fallout volume of as much as ~3.5 km3 (~1.5 km3 DRE).\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2017) reports a magnitude of 6.500, bulk eruptive volume of 3.900cubic km and a dense rock equivalent eruptive volume of 1.200 cubic km for the eruption.","StartYear":-3850,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":200,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kaguyak","ParentVolcano":"Kaguyak","VolcanoID":"ak143","ParentVolcanoID":"ak143"},{"ID":2301,"Name":"Edgecumbe Mid-Holocene Rhyolitic Tephra","Description":"From Riehle and others (1992): \"One or, locally, two thin layers of rhyolitic ash (3R287; Table 2 [in original text]) occur in soil above the latest Pleistocene fallout deposits on Kruzof Island and at Sitka. A 1-2 mm bed of very fine ash in sediment cored in a lake (not shown here) 45 km north of the MEF confirms a fall- out origin of the deposits. Deposits are coarsest (lapilli to 2 cm) and thickest (maximum of 5 cm) at Crater Ridge and southwest of Mount Edgecumbe (site 37, Fig. 1 [in original text]), implying two sources. Coarse deposits contain clasts of altered greywacke and subround pumiceous lapilli, suggesting eruption of a subsurface rhyolitic dome at a contact with greywacke.\"\r\n\"Riehle and Brew (1984) report overlying and underlying peat ages for these Holocene deposits of 4,030+/-90 and 4,310+/-140 yr B.P. (Beta 6004, 6005) at one site on Kruzof Island, and a single age of 5,760+/-70 yr B.P. (Beta 6003 ) from another site. The ages imply one eruption about 4.2 ka and another about 5.8 ka. The presence of only one deposit at some sites may be due to mixing of two layers by bioturbation and to limited overlap of fall- out from each ash plume. The ash bed in the sediment core is midway between the main fallout deposits and the sediment-water inter- face, consistent with a middle Holocene age.\"","StartYear":-3810,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Edgecumbe","ParentVolcano":"Edgecumbe","VolcanoID":"ak90","ParentVolcanoID":"ak90"},{"ID":2561,"Name":"Iskut-Unuk River cones 5600 yBP","Description":"From Hauksdottir and others (1994): \"Three cinder cones are identified (Fig. 2 [in original text]). The youngest cone lies to the south and appears to have fed the two youngest flows. It appears to have repeatedly erupted lava which dammed both Tom MacKay and Forrest Kerr creeks (B.C. Hydro, 1985). This inference is based on 14c dating of plant remains in lake sediments associated with these ephemeral dams. These age determinations (Table 1 [in original text], B.C. Hydro, 1985; Read and others, 1989) suggest lava effusion occurred 3800, 5600 and 6500-6800 years ago; the Iskut River Canyon was eroded to its present configuration in the last 3600 to 3800 years (B.C. Hydro, 1985).\"","StartYear":-3650,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iskut-Unuk volcanic field","ParentVolcano":"Iskut-Unuk volcanic field","VolcanoID":"ak136","ParentVolcanoID":"ak136"},{"ID":1411,"Name":"Akutan Flat Bight Valley Lahars","Description":"From Waythomas and others (1998): \"At least three lahar deposits and numerous, coarse-grained, black ash layers in Flat Bight (fig. 3 [in original text]) document an unknown number of minor eruptions from about 6000 years before present to about 1400 years before present.\"\r\nFrom Waythomas (1999): \"Stratigraphic exposures of unconsolidated voltaniclastic deposits are limited in Flat Bight valley, and only two sections were examined (Fig. 1 [in original text]). In upper Flat Bight valley, stream incision has exposed an 8-m-thick sequence of lahar deposits and tephra (section 81, Fig. 9 [in original text]). At least three thin noncohesive lahar deposits at the base of this section are separated by silty peat beds; the lowest peat bed yielded a radiocarbon age of 5420+/-120 years B.P. (Table 1 [in original text]). The lahar deposits are clast supported and contain a large proportion of rounded cobbles and small boulders that were likely entrained from the stream bed.\"","StartYear":-3470,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":120,"StartQualifierUnit":"Years","EndYear":550,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":1931,"Name":"Augustine Shuyak Island Ash 2","Description":"From Waitt and Beget (2009): \"On Shuyak Island 110 km southeast of Augustine (fig. 1A [in original text]), two fall tephras of Augustine chemical provenance (probe analysis of glass by J.R. Riehle and C.E. Meyer) date between about 6,460 and 5,020 yr B.P.\"","StartYear":-3380,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":30,"StartQualifierUnit":"Years","EndYear":-3070,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":30,"EndQualifierUnit":"Years","Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":2641,"Name":"Kaguyak Lower Ash Rib","Description":"From Fierstein (2007): \"The lower tephra ([sample] K-2500G) is 1 to 1.5-cm-thick and very fine-grained (Md=0.07 mm) in [the] Angle Creek section, but apparently thickens eastward to 3 cm on top of the Martin coulees (K-2661A; Fig. 3 [in original text]), where it is also a little coarser-grained (Md=0.12 mm). The glass is compositionally distinct from all other analyzed Martin and Mageik tephras (higher CaO/SiO2 and lower K2O/SiO2), and all major-element glass data plot in a coherent group that suggests affinity with the Kaguyak marker ash (Fig. 13a [in original text]). Additionally, the lower ash rib in Angle Creek is in the same stratigraphic position as that of the Kaguyak ash in the VTTS area. Magnetite data, however, preclude correlation between the two. Magnetite analyses yield a range of MgO (from 2.4-4 wt.% in K-2500G to 1.4-2.2 wt.% in K-2661A) and a range of TiO2 (10-14 wt.%) that is more similar to that of the upper grey ash (from Peulik) than to the tightly grouped data and the ∼8 wt.% TiO2 characteristic of the Kaguyak co-ignimbrite ash. This distinctive combination of glass and magnetite compositions has helped identify the \"lower ash rib\" at several locations in Angle Creek and suggests correlation with one of two fine-grained centimeter-thick pale orange tephras in the Griggs Fork ∼25 km ENE. Glass compositions ([samples] K-2440, K-2441, Fig. 13 [in original text]) and ilmenite data (not shown) for both samples at this location are consistent with lower ash rib and Kaguyak ash, but no magnetite has been analyzed so the compositional distinction between them is uncertain. However, radiocarbon dates on soil beneath the \"lower ash rib\" in Angle Creek are 5,265+/-95 and 5,160+/-160 14C years B.P. (sections K-2500 and K-2661, respectively), suggesting it is about 500 years younger than the Kaguyak co-ignimbrite ash.\"\r\n\"Although the data are inconclusive, several considerations suggest that this \"lower ash rib\" had a source at Kaguyak and is closely related to the caldera-forming eruption because: (1) Glass data are most similar to the Kaguyak ash and are dissimilar to tephra from the other Katmai volcanoes and from Peulik; (2) the \"lower ash rib\" is in a similar stratigraphic position in Angle Creek as the Kaguyak ash is in the lower VTTS; (3) apparent intimate mixing of the lower ash rib and Kaguyak tephras in one location in the lower VTTS suggest they were deposited closely in time; and (4) the tephra is everywhere fine grained, consistent with it being a distal ash from a nonlocal source. That the thickest ash measured is near the headwaters of Angle Creek may only be an artifact of preservation.\"\r\n\"Strongly contrary to the above are the wide ranges of magnetite compositions that are unlike those from ash and pumice related to the Kaguyak caldera-forming ignimbrite. Additionally, that the thickest preserved ash measured is in upper Angle Creek may reflect proximity to source and not be an artifact of preservation; pumice granules there are up to 5 mm across (although they are Frisbee-shaped with a low aspect ratio); and the median grain size is somewhat coarser than that a few kilometers westward (Table 1 [in original tex]). The Katmai volcanoes are well enough characterized that it seems unlikely this ash-with such distinctive glass compositions-came from Mounts Mageik, Katmai, or Griggs. No glass compositions similar to this ash have been found from Mount Martin, either, although the oxide data from this and the salt and pepper ashes are very similar. Some other non-local source seems most possible, whether Peulik, Kaguyak, or another Aleutian arc volcano that has had silicic Holocene activity.\"","StartYear":-3315,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":95,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kaguyak","ParentVolcano":"Kaguyak","VolcanoID":"ak143","ParentVolcanoID":"ak143"},{"ID":3121,"Name":"Spurr 5200 yBP","Description":"From Riehle (1985): \"Spurr tephra deposits are mainly dark scoriae of basaltic andesite composition which are predominant only within 100 km of the cone and which are assigned to the Crater Peak vent...One group consists of 3, provisionally correlated samples which define a marker horizon about 5200 yr old in the region northeast of Spurr. The 3 samples have nearly equal proportions of clinopyroxene, orthopyrocene, and amphibole and have trace amounts of biotite.\"","StartYear":-3250,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Spurr","ParentVolcano":"Spurr","VolcanoID":"ak260","ParentVolcanoID":"ak260"},{"ID":4401,"Name":"Akutan CFE","Description":"From Miller and others (1998): \"The caldera-forming eruption occurred about 5,200 yBP (Reeder, 1983) and was the source of small volume andesitic pyroclastic-flow deposits in valleys on the north, south, and east sides of the volcano (Miller and Smith, 1987; Romick and others, 1990).","StartYear":-3250,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":200,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":2381,"Name":"Fisher Turquoise Cone Collapse","Description":"From Stelling and others (2005): \"Post-caldera eruptive activity has been largely concentrated at two intracaldera cones, as well as one cone outside the caldera to the northwest. The western intracaldera center has been informally termed \"Turquoise Cone\" after its turquoise-colored crater lake (Fig. 3C [in original text]). A bench low on the southern flank of Turquoise Cone connects with the wave-cut terrace on the southern caldera wall, indicating that the Turquoise Cone edifice extended above lake level. The growth of Turquoise Cone was largely responsible for separating the large caldera lake and ultimately damming the northern lakes before the southern lake drained. The erupted products of Turquoise Cone are compositionally diverse, ranging from pl+ol+cpx high-alumina basalt to sparsely plagioclase-phyric dacite. The oldest deposits from Turquoise Cone are the most mafic (47 wt.% SiO2), whereas the last eruptions from this vent are the most silicic (66 wt.% SiO2).\"\r\n\"The present-day amphitheater-like form of Turquoise Cone resulted from a significant collapse event. Through geometric extrapolation of existing deposits and their inclinations, the pre-collapse volume of Turquoise Cone is estimated to have been ~3 km cubed, and slightly more than half of that volume has been removed. No deposits from the collapse event have been recognized, and we believe that they have been buried by subsequent eruptions from Turquoise Cone and other intracaldera vents. We are thus unable to constrain the trigger or structure of the collapse.\"\r\n\"Several pumice fall layers exposed inside and outside the caldera, and a dacitic lava flow on the northern flanks of the cone probably represent some of the last eruptions of Turquoise Cone (Table 1 in original text). We believe that these eruptions may have resulted in the collapse of Turquoise Cone. The pumice fall layers correlate compositionally with a tephra layer near Cold Bay, Alaska (120 km east), not only in major-element chemistry but delta 18 O signature (Bindeman and others, 2001). Exposures of these pumice deposits in the southeastern caldera wall are ~1 m thick ~12 km from Turquoise Cone, suggesting a significant Plinian eruption. Collapse from this eruption may not have been sufficiently large to remove the entire missing portion of Turquoise Cone, and removal of additional portions of the edifice may have occurred through subsequent phreatomagmatic eruptions. Soil directly below Turquoise Cone pumice deposits outside the eastern caldera wall has been dated at 5120 (+/-70) 14C years (Table 3 [in original text]), which is consistent with bracketing ages for the Cold Bay deposit of 6070 and 3600 years old (Carson, 1998; Dochat, 1997). If the collapse of Turquoise Cone resulted entirely or in part from this eruption, these data suggest an approximate date of collapse. Lacustrine deposits exposed on the northern shore of Turquoise Lake, and thus younger than the collapse event, have been dated to be 3490 (+/-50) 14C years old (Table 3 [in original text]), bracketing the collapse between~3500 and ~5100 years ago.\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2017) reports a magnitude of 6.2, bulk eruptive volume of 14.3 cubic km and a dense rock equivalent eruptive volume of 5.5 cubic km for the eruption.","StartYear":-3150,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-1550,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Fisher","ParentVolcano":"Fisher","VolcanoID":"ak100","ParentVolcanoID":"ak100"},{"ID":1591,"Name":"Dutton Debris Avalanche","Description":"From Miller and others (1999): \"As much as 0.3-0.5 km cubed of material slid off the western part of the upper edifice; the deposit has been dated at between 5080+/-100 and 6800+/-100 14 C yBP (Miller and others, 1999) and is probably closer to the latter age based on stratigraphic position.\"\r\n\"Debris avalanche deposits occur on the northwest and south flanks of the volcano Fig. 1 [of original text] where they underlie a total area of about 14 km square and have a combined volume of about 0.4 km cubed. The deposits in both areas are characterized by blocks as large as 10 m, enclosed in a poorly sorted matrix or lying on the surface. Megaclasts consist chiefly of cone-building andesitic lava Qcbf with some subordinate dacite. The dacite clasts are not prismatically fractured nor do they display other evidence of being hot, juvenile magmatic material at the time of the avalanche; their presence, however, is evidence that one or more domes had been emplaced before the edifice collapse that resulted in these deposits.\"\r\n\"The avalanche deposits are non-glaciated and are mid-Holocene in age. The similarity in clast size and composition and their proximity suggests the two deposits are of similar age, i.e., between 5080 and 6800 14C yBP (Miller and others, 1998, 1999).\"","StartYear":-3130,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":100,"StartQualifierUnit":"Years","EndYear":-4850,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":100,"EndQualifierUnit":"Years","Volcano":"Dutton","ParentVolcano":"Dutton","VolcanoID":"ak83","ParentVolcanoID":"ak83"},{"ID":1461,"Name":"Amak older volcanics","Description":"From Wood and Kienle (1990): \"The earlier volcanism, perhaps some 4,000-5,000 yr ago, consisted mostly of thin (~3 m) platy to massive andesite.\"\r\nFrom Marsh and Leitz (1978): \"The older series of flows built a low-lying conical volcano with a summit crater about 300 m in diameter. These flows are predominantly massive to platy, grayish-black, but sometimes slightly dark pink, two-pyroxene andesites. They show no sign of brecciation. On the southwest side of the island a small U-shaped valley cut into the older series indicates local glaciation.\"\r\n\"According to Funlc (1973) the latest period of glaciation in this area was about 6,700 years B.P. The small U-shaped glacial valley cut into the older series was probably excavated during this period of glaciation. The older flows also show no sign of being extruded beneath ice. Thus Amak is probably not much older than 6,700 years.\"","StartYear":-3050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-2050,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Amak","ParentVolcano":"Amak","VolcanoID":"ak8","ParentVolcanoID":"ak8"},{"ID":3591,"Name":"Makushin Mid-Holocene Tephras","Description":"From Beget and others (2000): \"Following the caldera-forming eruptions, frequent but smaller events have occurred up to the present time (fig. 4 [in original text]). The most complete record of Makushin eruptions is found in the upper Makushin Valley, where at least 26 volcanic ash layers, some as much as 5 centimeters thick, are preserved in peat formed on the surface of the valley fill during the last 4,000 years. Several small pyroclastic flow and surge deposits found on the northeast, north, southeast, and west flanks of Makushin Volcano record eruptions that affected the volcano’s flanks up to 8 kilometers from the vent. Lahar and flood deposits, possibly produced by small eruptions, are present at low elevations in virtually all streams draining the volcano and can also be traced 8 to 10 kilometers downvalley from the vent.\"\r\nFrom Bean (1999): \"A stratigraphic section from a fan in Makushin Valley (Fig. 10.1 [in original text]) has preserved an excellent record of small eruptive events over the last ~5000 years. Section 96MAK03 preserves 29 prehistoric tephras above a peat dated at 4910+/-80 14C yr B.P. This is a minimum estimate on the number of eruptions because of varying wind directions, indistinguishable multiple fall layers, and erosion. It is unlikely that one section would preserve all erupted tephras. Also, the smallest magnitude eruptions are often not distinctly preserved in the geologic record.\"","StartYear":-3030,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":90,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":1481,"Name":"Black Peak CFE","Description":"From Miller and Smith (1987): \"Black Peak is the middle and smallest (3 km diameter) of the three neighboring calderas. Ash-flow tuffs as much as 100 m thick are exposed in two large drainages on the west side of the volcano The tuffs appear to have been more passively emplaced as compared to those from the neighboring calderas, and they have a large air-fall component. In spite of the caldera’s small diameter, the apparent widespread distribution of climactic air fall and thickness of the ash-flow tuffs suggest a bulk eruption volume of \u003e10 km cubed.\"\r\n\"Attempts to find charcoal in, or organic material directly beneath, the ash-flow tuff were unsuccessful. However, organic material from beneath a distinctive coarse air-fall tuff, assumed to represent the climactic caldera-forming eruption of Black Peak, yielded 14C ages of 4470+/-200, 4170+/-90, and 4700+/-100 yr (samples 12-14, Table 1 [in original text]). These are maximum ages; sample 17, dated at 3660+/-90 B.P. is a minimum age from organic material overlying the climactic air fall. These dates are consistent with the tephra stratigraphy and suggest a date somewhere between 3660 and 4170-4700 B.P. for the caldera-forming eruption of Black Peak.\"\r\nFrom Waythomas (2015): \"Thick pyroclastic deposits in the vicinity of the volcano and extensive ash fallout that formed a prominent regional tephra layer.\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2017) reports a magnitude of 6.5, bulk eruptive volume of 30 cubic km and a dense rock equivalent eruptive volume of 12 cubic km for the eruption.","StartYear":-2750,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":100,"StartQualifierUnit":"Years","EndYear":-1710,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":90,"EndQualifierUnit":"Years","Volcano":"Black Peak","ParentVolcano":"Black Peak","VolcanoID":"ak25","ParentVolcanoID":"ak25"},{"ID":2811,"Name":"Koniuji 4600 yBP","Description":"From Jicha (2009): \"Two experiments from a plagioclase-phyric, mafic andesite (58.1 wt.% SiO2) that flowed over the 5.8 ka unit and formed a headland on the northwest corner of the island gave a 40Ar/39Ar age of 4.6+/-2.0 ka (Figs. 2-4 [in original text]). Large boulder-sized xenoliths of the 5.8 ka lava were observed within the 4.6 ka lava (Fig. 3 [in original text]).\"\r\n\"The composition of the eruptive products evolved slightly as a 4.6 ka mafic andesite (58.1 wt.% SiO2) flowed over the 5.8 ka basaltic andesitic unit and formed a headland on the northwest corner of the island. Several meters of tephra blanket the 4.6 ka and the older lava flows, but these deposits were not thoroughly investigated and may or may not be from Koniuji.\"\r\n\"A broad crescent-shaped scarp, concave to the west, makes up the western half of the Koniuji Island, but this feature is narrower and much smaller in area than the deep seated failures observed at large Aleutian stratovolcanoes such as Kiska, Tanaga, Kanaga, and Great Sitkin (Coombs and others, 2007). I suggest that the steep-sided western edge of the island may be a collapse scar. Because the 5.8 ka basaltic andesitic lava is located within this feature and the northern edge of the scarp is formed by the 4.6 ka andesite, the age of the collapse must be b 4.6 ka. The sector collapse at Koniuji is similar to the thin-skinned failures at Gareloi (178.8 degrees W), which did not excavate deeply into the edifice (Coombs and others, 2007).\"","StartYear":-2650,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":2000,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Koniuji","ParentVolcano":"Koniuji","VolcanoID":"ak168","ParentVolcanoID":"ak168"},{"ID":4061,"Name":"Aniakchak ECR-162 Tephra","Description":"From Payne and others (2008): \"The ECR 162 tephra is the most geochemically distinctive tephra located in these sites. EPMA data suggest a good correlation with tephra from Aniakchak. The tephra is dated 5300-5030 cal yr BP, considerably older than the very large caldera-forming event in the fourth millennium BP (Aniakchak II; Miller and Smith, 1987; Begét and others, 1992). A previous caldera-forming event is probably older than this tephra (ca. 8200 cal yr BP; VanderHoek and Myron, 2004). There are no known Aniakchak eruptions around this date. Miller and Smith (1987) discussed an eruption of the adjacent Black Peak with an uncalibrated date of 4470+/-200 14C yr BP, very close to the uncalibrated date of ECR162 at 4485+/-30 14C yr BP. However, geochemical similarity with Black Peak tephra is low, although there are comparativelyfew published data from this volcano (Riehle and others, 1999). Despite the similarity in age with Black Peak, based on the geochemical composition the most probable source of the tephra is a previously unknown eruption of Aniakchak.\"","StartYear":-2535,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":30,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":2431,"Name":"Hayes Tephra A","Description":"From Wallace and others (2015): \"Tephra A respresents an eruption of rhyolitic and dacitic magma as recent as 4,450+/-30 14C yr B.P. The rhyolite component of tephra A is compositionally and mineralogically distinct from the younger dacite tephras. It should be possible to recognize and correlate distal equivalents to tephra A by the absence of amphibole and pyroxene, and an abundance of small biotite grains and quartz in the rhyolite fraction of the deposit. Tephra A magnetites have unusually low MgO and Al2O3and high MnO, which may also be useful for recognizing distal equivalents.\"\r\n\"Tephra A (AT-2558) is oxidized, which imparts a moderate brown color to the deposit (fig. 6 [in original text]). Tephra A contains two compositions of pumice, a bright white low-silica rhyolite (72.8 weight percent SiO2 whole-rock composition; all SiO2concentrations reported for analyses recalculated to sum to 100 weight percent volatile-free) with high-silica rhyolite matrix glass (76.5 weight percent SiO2) and a creamy white dacite with rhyolite matrix glass (70.8 and 72.4 weight percent SiO2) (tables 4, 5 [in original text]). The sample is dominantly composed of pumice grains (rather than glass shards) and free crystals. Pumices are generally inflated and glassy. Rhyolite lapilli contain feldspar and quartz in a glassy groundmass with biotite microlites and aligned vesicles (fig. 7E [in original text]). Plagioclase and amphibole are the dominant phenocrysts phases in dacite lapilli (fig. 7F [in original text]). Proportions of the two lapilli types are unknown. Rare biotite (\u003c1 percent) is observed in all size fractions. Mafic mineral point counts suggest a high amphibole to pyroxene ratio (table 3, fig. 8 [in original text]). In general, mafic minerals as free crystals are rare compared to pumice grains and felsic crystals. Glass in both lapilli types was easy to analyze by electron microprobe owing to the relatively large areas between vesicles.\"","StartYear":-2500,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":30,"StartQualifierUnit":"Years","EndYear":-1740,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":30,"EndQualifierUnit":"Years","Volcano":"Hayes","ParentVolcano":"Hayes","VolcanoID":"ak116","ParentVolcanoID":"ak116"},{"ID":2681,"Name":"Kanaga T4","Description":"From Waythomas and others (2001): \"Groups of tephra deposits so defined indicate that at least 11 eruptions of Kanaga Volcano have occurred since about 11 ka. Most of these eruptions were probably sub-Plinian to Plinian, producing moderately vesicular dacitic pumice lapilli tephra deposits ranging in thickness from a few centimeters to more than 1 m (table 2 [in original text]).\"\r\n\"Gray lithic lapilli fall deposit.\"","StartYear":-2460,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-2139,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kanaga","ParentVolcano":"Kanaga","VolcanoID":"ak144","ParentVolcanoID":"ak144"},{"ID":2971,"Name":"Moffett Sandwich Ash","Description":"Waythomas and others (2003) tentatively identify Moffett Volcano as the source of the Sandwich Ash, observed on Adak Island and also called AD-3 by Kiriyanov and Miller (1997). \r\nFrom Kiriyanov and Miller (1997): \"AD-3 ash ranges between 1.5 and 17 cm (average 10-12 cm) in thickness and consists of a gray silt-size particles, inequigranular sand, and pumice lapilli up to 5 cm (mainly 1 cm) in size. The thickness of this ash layer varies considerably from section to section. The particle size of this ash generally grows larger westward. In some of the sections, this ash was fond to be intercalated with a layer of humus sandy loam. Apparently, these two ash layers were ejected from the same vent during different eruptions with a small time interval between them. Characteristic features of this ash (Fig. 5 [in original text]) are a high glass content (76%), absence of green hornblende, and the low contents of pyroxenes (3%) and brown hornblende (2%). The carbon-14 age of the ash was found to be ~2000 years (Table 1 [in original text]).\"\r\nFrom Okuno and others (2012): \"The Sandwich tephra-fall deposit covers a 74cm thick sequence of tephra-soil complexes, is 20cm thick, and comprises alternating lenses of ash and pumice (MP is 0.9cm). As Kiriyanov and Miller (1997) noted, the thickness and lithology of the Sandwich tephra vary from section to section, and humus loams are intercalated in the tephra in some places. The ash and pumice beds of the Sandwich tephra infill the erosion gully in the humic soil layer, which contains the Sandwich pumice lapilli at Site 2 on the southern slope of Adagdak Volcano (Figure 4.6 [in original text]). We attribute this humus layer to a contemporaneous reworking associated with the eruption of the Sandwich tephra and thus consider this humic layer as a pseudo-soil. Two fine grained tephra layers: the YBO (5cm thick) and Forty Year (6cm thick) are located as tephra-soil complexes between the Sandwich tephra and the ground surface (Figures 4.2 and 4.5 [in original text]).\"","StartYear":-2440,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":150,"StartQualifierUnit":"Years","EndYear":-1875,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":105,"EndQualifierUnit":"Years","Volcano":"Moffett","ParentVolcano":"Moffett","VolcanoID":"ak192","ParentVolcanoID":"ak192"},{"ID":2691,"Name":"Kanaga T5","Description":"From Waythomas and others (2001): \"Groups of tephra deposits so defined indicate that at least 11 eruptions of Kanaga Volcano have occurred since about 11 ka. Most of these eruptions were probably sub-Plinian to Plinian, producing moderately vesicular dacitic pumice lapilli tephra deposits ranging in thickness from a few centimeters to more than 1 m (table 2 [in original text]).\"\r\n\"Pumice-lithic lapilli fall deposit.\"","StartYear":-2402,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-1979,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kanaga","ParentVolcano":"Kanaga","VolcanoID":"ak144","ParentVolcanoID":"ak144"},{"ID":2311,"Name":"Edgecumbe Second Mid-Holocene Rhyolitic Ash","Description":"From Riehle and others (1992): \"One or, locally, two thin layers of rhyolitic ash (3R287; Table 2 [in original text]) occur in soil above the latest Pleistocene fallout deposits on Kruzof Island and at Sitka. A 1-2 mm bed of very fine ash in sediment cored in a lake (not shown here) 45 km north of the MEF confirms a fall- out origin of the deposits. Deposits are coarsest (lapilli to 2 cm) and thickest (maximum of 5 cm) at Crater Ridge and southwest of Mount Edgecumbe (site 37, Fig. 1 [in original text]), implying two sources. Coarse deposits contain clasts of altered greywacke and subround pumiceous lapilli, suggesting eruption of a subsurface rhyolitic dome at a contact with greywacke.\"\r\n\"Riehle and Brew (1984) report overlying and underlying peat ages for these Holocene deposits of 4,030+/-90 and 4,310+/-140 yr B.P. (Beta 6004, 6005) at one site on Kruzof Island, and a single age of 5,760+/-70 yr B.P. (Beta 6003 ) from another site. The ages imply one eruption about 4.2 ka and another about 5.8 ka. The presence of only one deposit at some sites may be due to mixing of two layers by bioturbation and to limited overlap of fall- out from each ash plume. The ash bed in the sediment core is midway between the main fallout deposits and the sediment-water inter- face, consistent with a middle Holocene age.\"","StartYear":-2360,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":140,"StartQualifierUnit":"Years","EndYear":-2080,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":90,"EndQualifierUnit":"Years","Volcano":"Edgecumbe","ParentVolcano":"Edgecumbe","VolcanoID":"ak90","ParentVolcanoID":"ak90"},{"ID":3131,"Name":"Spurr 4159 yBP","Description":"From Waythomas and Nye (2002): \"The present caldera formed during a major flank collapse of Mount Spurr volcano that either caused or resulted from a major eruption in late Pleistocene or early Holocene time. A discontinuous mantle of pyroclastic debris composed of high-silica andesite rests directly on the debris-avalanche deposits on the proximal south flank of the volcano. The debris-avalanche and pyroclastic-flow deposits and the caldera structure itself are the primary evidence that the eruption and flank collapse were initiated by magmatic activity (fig. 4 [in original text]).\"\r\nFrom Waythomas (2007): \"Radiocarbon-dated volcanic mass-flow deposits on the southeast flank of Mount Spurr in south-central Alaska provide strong evidence for the timing of large-scale destruction of the south flank of the volcano by sector collapse at 4,769-4,610 yr B.P. The sector collapse created an avalanche caldera and produced an ~1-km3-volume clay-rich debris avalanche that flowed into the glacially scoured Chakachatna River valley, where it transformed into a lahar that extended an unknown distance beyond the debris avalanche. Hydrothermal alteration, an unbuttressed south flank of the volcano, and local structure have been identified as plausible factors contributing to the instability of the edifice. The sector collapse at Mount Spurr is one of the later known large-volume (\u003e1 km3) flank failures recognized in the Aleutian Arc and one of the few known Alaskan examples of transformation of a debris avalanche into a lahar.\"\r\n\"Cryptodome intrusion, which is also a plausible mechanism for the sector collapse at Mount Spurr, could have initiated a deep-seated failure of the volcano (Siebert, 1984; Siebert and others, 1987; Donnadieu and others, 2001). At other volcanoes, deep-seated failures associated with cryptodome intrusion commonly have a substantial magmatic component, though apparently not at Mount Spurr because extensive pyroclastic flow and fall deposits associated with this event have not been recognized.\"\r\n\"Radiocarbon-dated wood from the clay-rich lahar deposit that evolved from the debris-avalanche deposit now provides direct evidence for the timing of flank collapse at Mount Spurr. Six samples of wood from the lahar deposit that were dated by conventional radiocarbon scintillation-counting techniques yielded raw 14C ages of 4,040+/-70, 4,060+/-60, 4,180+/-70, 4,210+/-50, and 4,230+/-50 yr B.P. (table 1 [in original text]). Using the radiocarbon calibration program of Stuiver and others (1998), calibrated 2 sigma age ranges for the wood samples were determined (table 1 [in original text]). If the anomalous age is excluded, the average age of the wood samples is 4,159+/-26 yr B.P., and the calibrated 2 sigma age range is 4,610-4,769 yr B.P., which constrains the timing of emplacement of the lahar, the associated debris avalanche, and sector collapse to this interval.\"","StartYear":-2209,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":26,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Spurr","ParentVolcano":"Spurr","VolcanoID":"ak260","ParentVolcanoID":"ak260"},{"ID":2701,"Name":"Kanaga T6","Description":"From Waythomas and others (2001): \"Groups of tephra deposits so defined indicate that at least 11 eruptions of Kanaga Volcano have occurred since about 11 ka. Most of these eruptions were probably sub-Plinian to Plinian, producing moderately vesicular dacitic pumice lapilli tephra deposits ranging in thickness from a few centimeters to more than 1 m (table 2 [in original text]).\"\r\n\"Pumice-lithic lapilli fall deposit.\"","StartYear":-2109,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-1639,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kanaga","ParentVolcano":"Kanaga","VolcanoID":"ak144","ParentVolcanoID":"ak144"},{"ID":2901,"Name":"Mageik Orange Dacite Lapilli Fall (ODLF)","Description":"From Fierstein (2007): \"From the vent at an elevation of 2,010 m, two of the flows extend 6 km to termini as low as 300-350 m in Martin Creek; we call these the \"south lobes\". One of the youngest flows bifurcates to the northeast; we call this the \"Y-flow\". The rim of the ice-filled crater on the East Summit is strewn with coarse scoriae and dense glassy blocks of phreatomagmatic ejecta, deposited upon the surfaces of thin lava flows exposed locally. Compositional data for one such ejecta block is used here to represent the \"East Summit\" in the following correlations.\"\r\n\"Considerable overlap in the microprobe data between the different East Mageik lavas and tephras (Fig. 23 [in original text]) preclude firm correlations, but we tentatively suggest that the magnetite data correlate the south lobes with ODLF [orange dacite lapilli fall] ash (3,800-4,000 14C years B.P.)...\"\r\n\"One of the most distinctive tephra layers in Windy Creek and the lower reaches of the VTTS is an orange-stained dacite fallout unit that typically lies 20-60 cm beneath the 1912 deposits and stratigraphically below the two grey ash layers just described. The dacite lapilli themselves are not particularly distinctive, having phenocrysts typical of most other dacitic fallout in the region (plagioclase+FeTi oxides+sub-equal proportions of opx and cpx; Table 1 [in original text]). In uppermost Windy Creek, where both the \"lower grey ashfall\" and ODLF units are coarse granules and lapilli and are rarely separated by a soil horizon, the two are distinguished in the field principally by abrupt fining at the top of the ODLF unit (Fig. 9 [in original text]). Only there are the two fall units so similar; farther down Windy Creek, the ODLF unit is always coarser than the lower grey ash (Figs. 8, 9 [in original text]). Soil does separate the two fall units in the lower VTTS area, where the ODLF layer is distinctive because it is widely preserved and is coarser-grained than the other pre-1912 ash layers there. Where best preserved in the upper reaches of Windy Creek, this 20-cm-thick fall unit is reversely graded at its base, with the coarsest pumice lapilli (as large as 5.5 cm, commonly to 2-3 cm) in the middle of the layer, but grading normally up to fine grey ash at its top (Fig. 9 [in original text]). Another 11 km northward in lower Windy Creek, the ODLF thins to 5 cm, with the largest pumice lapilli just over 1 cm; and 8 km still farther ENE, it thins to half that (2.5 cm) and the largest clasts fine to only a few millimeters. Only a whiff of this ash is found 1.75 km still further ENE, where locally preserved, poorly defined ash remnants are barely 3-4 mm thick.\"\r\n\"ODLF lapilli and granules are conspicuous on cutbanks because of their orange color, which is pervasive in smaller clasts, but only surficial on larger (fundamentally grey to tan) ones. The nearly ubiquitous orange coloring of almost all lapilli and granules indicates eruption-related oxidation, not in-situ weathering of the dacitic clasts. The thickness and coarseness of this fall unit in Windy Creek suggests a source at one of the nearby Holocene vents, Mount Martin or East Mageik. The layer is also preserved along Angle Creek, where it is markedly thinner and finer than along Windy Creek (Fig. 8 [in original text]). Isopachs and isopleths suggest a narrow northerly distribution of the ODLF fallout.\"\r\n\"Whereas in the lower VTTS and Windy Creek the lower grey fall unit is difficult to distinguish in the field from the upper grey ash, in Angle Creek the difficulty becomes distinguishing it from the ODLF. Both are orange-stained lapilli-to-granule falls in the headwaters of Angle Creek, indistinguishable in the field or by titanomagnetite analyses in the lab (Fig. 10a [in original text]). Discrimination is achieved, however, by their glass compositions. Although the data fields overlap, the ODLF is, overall, less silicic (71-76% SiO2) than the lower grey ash (74.5-78% SiO2; Fig.10b [in original text]). Where both are preserved in a single section farther downstream in Angle Creek they are separated by as much as 30 cm of dense brown peat (section K-2500; Fig. 3 [in original text]). There, the ODLF (K-2500H) is a 1-cm thick fine to medium ash (maximum clasts ∼0.3 cm) whereas the \"lower grey ash\" is a 5-cm-thick coarser granule layer (maximum clasts to 0.6 cm). Thickness data thus clearly show that the ODLF came from East Mageik, as it thins toward Mount Martin from its thickest exposures in Windy Creek. 14C dates on soils beneath and above the orange dacite lapilli fall bracket its deposition between ∼3,600 and ∼4,300 14C years (Figs. 3, 4; Table 2 [in original text]), although stratigraphy and evaluation of the 14C dates favors 3,800 to 4,000 years.\"","StartYear":-2060,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":90,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mageik","ParentVolcano":"Mageik","VolcanoID":"ak187","ParentVolcanoID":"ak187"},{"ID":3921,"Name":"Great Sitkin 4000 yBP","Description":"From Waythomas and others (2003): \"Pumice lapilli tephra deposit.\"","StartYear":-2050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-1650,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":2471,"Name":"Iliamna 4000 yBP","Description":"From Waythomas and others (1999): \"At least two fine-grained volcanic-ash deposits from Iliamna Volcano have been identified on the Kenai Peninsula. These ash layers are within a vertical sequence of peat and volcanic-ash deposits from other Cook Inlet volcanoes and have been radiocarbon dated and geochemically correlated with a pumiceous lapilli tephra found on the proximal flanks of Iliamna Volcano. A discontinuous mantle of pumiceous lapilli tephra is common on bed-rock pinnacles that extend above modern glaciers northeast of Iliamna Volcano. This tephra deposit is found as much as 50 kilometers northeast of the present summit of Iliamna Volcano. The pumiceous lapilli tephra and fine ash layer on the Kenai Peninsula are evidence for a large  plinian eruption of Iliamna Volcano from a vent on the northeast upper flank of the volcano about 4,000 yr B.P.\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2017) reports a magnitude of 4.000, bulk eruptive volume of 0.100 cubic km and a dense rock equivalent eruptive volume of 0.040 cubic km for the eruption.","StartYear":-2050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":1881,"Name":"Augustine Kamishak Creek Tephra","Description":"From Waitt and Beget (2009): \"Along Kamishak Creek 70 km southwest of Augustine (fig. 1A [in original text]), a fall tephra of Augustine provenance dates between about 3,850 and 3,660 yr B.P. (table 2 [in original text]) (Riehle and others, 1998, fig. 8 [in original text]).\"","StartYear":-1900,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":100,"StartQualifierUnit":"Years","EndYear":-1710,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":100,"EndQualifierUnit":"Years","Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":1581,"Name":"Dana Block and Ash Flow","Description":"From Wood and Kienle (1990): \"A block-and-ash flow erupted 3,840 yBP fills valleys south and west of the crater.\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2017) reports a magnitude of 5, bulk eruptive volume of 1.0 cubic km and a dense rock equivalent eruptive volume of 0.40 cubic km for the eruption.","StartYear":-1890,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Dana","ParentVolcano":"Dana","VolcanoID":"ak72","ParentVolcanoID":"ak72"},{"ID":2441,"Name":"Hayes Tephra Set H","Description":"The Hayes tephra set H has a complicated history of nomenclature, tephra name aliases include the Jarvis Creek Ash (Reger and others, 1964), Cantwell Ash (Bowers 1979), Watana (upper oxidized and lower unoxidized) tephra (Dixon and Smith, 1990), and Tangle Lakes Tephra (Beget and others, 1991).\r\nFrom Riehle and others (1990): \"The most widespread of all Holocene tephra deposits in the Cook Inlet region of south-central Alaska is a set of deposits from Hayes volcano. Because of their unique phenocryst content-biotite in rare amounts and a high proportion of amphibole to pyroxene-the deposits are readily identifiable at all but the most distant sites where they are very fine grained...The set originated at Hayes volcano in the Tordillo Mountains 150 km northwest of Anchorage: seven or possibly eight closely succeeding deposits, low-silica dacite in composition, compose two main lobes that extend northeast for 400 km and south for at least 250 km from the vent. We estimate the total tephra volume to be 10 km 3; multiple layers imply four to six larger and two or three smaller eruptions.\"\r\nFrom Beget and others (1991): \"The geochemistry, petrography, and distribution of the Jarvis Creek Ash (Pewe 1965, 1975a) indicate that this tephra from the lower Delta River area of central Alaska is correlative with volcanic ash from sites in south-central Alaska near Tangle Lakes (upper Delta River area) and the Cantwell ash from Hayes volcano found in the upper Nenana River area (Riehle and others, 1990). Volcanic glass compositions of distal Jarvis Creek and Tangle Lakes tephra samples are compositionally restricted, while several discrete glass populations are present in some Cantwell samples collected nearer Hayes volcano. These correlations extend the known distribution of Hayes volcano tephras across the Alaska Range and into central Alaska, a distance of more than 650 km.\"\r\nRiehle (1994) proposed, \"...that the group of beds be informally referred to as Hayes tephra set H (for Hayes River Pass, the site of the reference samples). As previously applied to the Hayes deposits (Riehle and others, 1990), a set is two or more closely succeeding tephra deposits that are chemically or mineralogically similar (Mullineaux and others, 1975). The designation \"H\" allows for future recognition of other tephra sets. The name \"Hayes tephra set H\" emphasizes source (consistent with NACSN, p. 851) and implies that each deposit is part of a group which has a wide geographic extent.\"\r\nFrom Wallace and others (2015) [Hayes Volcano proximal reference study]: \"Tephra fallout, eolian silt deposits, and buried soils make up the uppermost two meters of the Hayes River exposure at site 11HYKLW001 (figs. 1B, 2 [in original text]). Tephra deposits generally correlative with tephra set H are exposed ~1 m below the surface and consist of 10 tephra-fall layers distinguished by variations in particle size, bedding, color, or separation by buried soils (figs. 5, 6 [in original text])...Individual tephra layers range from 1-40 cm thick. On the basis of thickness, grain size, and proximity, eight of the ten tephra-fall deposits were probably erupted from Hayes Volcano (31 km)...Tephras F and H are sufficiently thick to be sub-sampled to test for compositional variation. Six buried soils are evident in this section and all but one were sampled for radiocarbon dating.\"\r\n\"Tephra B (AT-2559) is a non-oxidized, clean, salt-and-pepper colored tephra that contains bright white dacite pumice with rhyolite matrix glass (72.8 weight percent SiO2; table 5 [in original text]). Pumices are highly inflated, glassy, and contain phenocrysts of plagioclase, amphibole, and Fe-Ti oxides in clear microlite-free matrix glass (fig. 7G [in original text]). Plagioclase phenocrysts are notably fritted, or \"sieved\" (fig. 7H [in original text]), more so than in other tephras in the sequence. Although point count data on pumice grains were not collected because of the small grain size, the pumice grains are relatively crystal poor yet the deposit contains abundant glass-coated free crystals.Rare (\u003c1 percent) biotite grains are observed in all size fractions and exhibit both euhedral and irregular forms. Mafic mineral counts suggest a high amphibole to pyroxene ratio (table 3, fig. 8 [in original text]). Because of the highly vesicular glass, locating areas large enough to analyze by microprobe was difficult.\"\r\n\"Tephra D (AT-2567) is dominated by dense, light-medium gray, fresh-looking lithic grains and minor cream-white pumice which impart an overall medium gray color to the deposit in wet and dry samples (fig. 6 [in original text]). The lithic grains and pumice contain phenocrysts of plagioclase, amphibole, and Fe-Ti oxides. Lithic grains have grayish microlite-rich matrix glass (not analyzed) while the pumices have clear rhyolite matrix glass (73.6 weight percent SiO2) (fig. 7I [in original text]). Rare (\u003c1 percent) biotite grains are observed in all size fractions and exhibit euhedral and irregular forms. Mafic mineral counts suggest a high amphibole to pyroxene ratio (table 3, fig. 8 [in original text]).\"\r\n\"Tephra E (AT-2565) is dominated by dense, light-medium gray, fresh-looking lithic grains and minor cream-white pumice, which impart an overall pale yellowish brown color to the deposit in both wet and dry samples. The lithic and pumice grains contain phenocrysts of plagioclase, amphibole, and Fe-Ti oxides (fig. 7J [in original text]). The lithic grains have grayish microlite-rich matrix glass (not analyzed) while the pumice grains have clear microlite-rich matrix glass that is rhyolitic in composition (72.7 weight percent SiO2) (table 5 [in original text]). Biotite is very rare in this sample and only a few grains were observed. Mafic mineral counts suggest a high amphibole to pyroxene ratio (table 3, fig. 8 [in original text]). Despite being microlitic, pumice glass in this sample is fairly easy to analyze with the electron microprobe.\"\r\n\"Tephra F is 40-cm thick and was subsampled into two parts, (A) the coarse-grained bottom 10 cm (tephra F1, AT-2560), and (B) the finer-grained upper 30 cm (tephra F2, AT-2561) to assess compositional variation (figs. 5, 6 [in original text]). The overall deposit color is very pale orange. Both samples contain cream-white dacite pumice (WR, 63.8 weight percent SiO2) with mostly microlite-free rhyolitic matrix glass (71.3-74.1 weight percent SiO2) (tables 4, 5 [in original text]). Glass composition within the upper unit (tephra F2) appears to have higher silica content (74 percent SiO2) compared to the lower section (tephra F1, 71-72 weight percent SiO2). Minor amounts of dense, light-medium gray lithic grains are present but were not analyzed. Pumice \u003e0.250 mm tends to be more oxidized and have a pale yellow brown color while smaller grains (\u003c 0.125 mm) tend to be pure white. Both pumice and lithic clasts contain phenocrysts of plagioclase, amphibole, and Fe-Ti oxides. Rare (\u003c1 percent) biotite grains are observed in all size fractions and exhibit euhedral and irregular forms, including large grains as much as 2 mm in diameter. Mafic mineral counts suggest a high amphibole to pyroxene ratio (table 3, fig. 8 [in original text]). Despite the glass being mostly microlite free, some grains are highly vesicular, making glass analysis difficult (figs. 7K, L [in original text]).\"\r\n\"Tephra G (AT-2562) is dominated by dense, light-medium gray, fresh-looking lithic grains with minor cream-white pumice, which impart an overall medium gray color to the deposit in wet and dry samples (fig. 6 [in original text]). The matrix glass of the pumice is bimodal high-silica (74.6 and 77.8 weight percent SiO2) rhyolite (table 5). Both lithic and pumice grains contain phenocrysts of plagioclase, amphibole, and Fe-Ti oxides. The lithic grains have grayish microlite-rich matrix glass, whereas the pumice grains have microlite-free clear glass and microlite-rich grayish glass. Rare (\u003c1 percent) biotite grains are observed in all size fractions and exhibit both euhedral and irregular forms. Mafic mineral counts suggest a high amphibole to pyroxene ratio (table 3, fig. 8 [in original text]). Pumice clasts are generally highly vesicular and the sample is difficult to analyze by electron microprobe because the threads of glass are narrow and microlite-bearing (figs. 7M, N [in original text]).\"\r\n\"Tephra H is 20-cm thick and was subsampled into 2 parts, (A) the coarse-grained bottom 10 cm (tephra H1, AT-2563), and (B) the finer-grained upper 10 cm (tephra H2, AT-2564) to assess compositional variation (fig. 5 [in original text]). Unit H contains grayish orange oxidized pumice, which imparts a dark yellowish orange oxidized color to the deposit in wet and dry samples (fig. 6 [in original text]). A minor amount of dense, light-medium gray lithic material is present in this sample but was not analyzed. The pumice matrix glass is clear, microlite-rich, and vesicle textures are generally fluidal (fig. 7O, P [in original text]). Glass from the lower part of tephra H (H1) is bimodal with nearly subequal populations of dacite and rhyolitic (65 and 75 weight percent SiO2) while glass from the upper part of tephra H (H2) has an entirely rhyolite composition (75.3 weight percent SiO2). Rare (\u003c1 percent) biotite grains are observed in all size fractions and exhibit euhedral and irregular forms. Mafic mineral counts suggest a high amphibole to pyroxene ratio (table 3, fig. 8 [in original text]). Despite the glass being microlitic, this sample is fairly easy to analyze on the electron microprobe owing to the relatively large areas between vesicles.\"\r\n\"Tephras B, F, G, and H of Unit III, as well as the underlying Units I and II, are the most significant and distinctive deposits of the Hayes River outcrop and are the most likely to represent widespread deposits in south-central Alaska.\"\r\n\"On the basis of major-element glass compositions (fig. 10 [in original text]), we find that the Jarvis Ash Bed correlates most closely with our tephra F, which is the thickest tephra at the Hayes River outcrop (40 cm), and the only tephra that contains medium (4-16 mm) lapilli (fig. 16 [in original text]). This may be consistent with the conclusions of Riehle and others (1990), who indicated that tephra G at site 23 was deposited from a northward-directed ash cloud that would have travelled over interior Alaska.\"\r\n\"Combellick and Pinney (1995) describe a 3-cm-thick tephra on the Kenai Peninsula dated at 3,530+/-70 14C yr B.P. They conclude, on the basis of major-element glass chemistry and minerology, that it correlates with unit A of Riehle (1985), the uppermost tephra at his site 23 (table 9, figs. 8, 10 [in original text]). The glass composition of this tephra is most similar to our tephra H, which is also the uppermost tephra at the Hayes River outcrop (fig. 10 and 16 [in original text]).\"\r\n\"The Watana tephra has a distinctive upper oxidized component and lower non-oxidized component in subaerial exposures, and as many as three discrete layers in a lake-sediment core. The tephra ranges in thickness from 6-20 cm, and has an age within the range of 2,830-5,270 14C yr B.P. based on radiocarbon ages of numerous paleosols bounding this layer in the Susitna River valley (J.E. Dixon and others, written commun(s)., 1985; Dilley, 1988).\"\r\nFrom Mulliken (2016): \"Stratigraphically, the Watana tephra is separated into an upper and lower component, and there has been some question as to whether the deposit represents a single or multiple volcanic events (Dixon and others 1985). Glass geochemical analyses demonstrate that the deposit is relatively homogenous despite differences in oxidation and color. Similarity coefficients calculated between mSRV Watana reference tephra samples and proximal Hayes Volcano reference samples suggest that the Watana tephra is correlative with the Hayes tephra set; however, most archaeological samples were taken as bulk Watana tephra samples, rather than as separate samples from the oxidized upper and unoxidized lower components of the tephra, which complicates correlation efforts. Specifically, Watana tephra samples correlate, with similarity coefficients greater than 0.95, to Hayes River Outcrop tephras D, E, F2, H (H1 and H2) of Wallace and others (2014). Proximal tephras F and H represent eruptions large enough to have been deposited distally; the two samples of unoxidized portion of the Watana tephra have high similarity coefficients with proximal tephra F2, which is also unoxidized, whereas the two samples of the upper oxidized portion of the Watana tephra have high similarity coefficients with proximal tephra H, which is also oxidized.\"\r\n\"These results suggest that the Watana oxidized/unoxidized tephra couplet represents proximal tephras F and H of Wallace and others (2014) (Figure 6.1 [in original text]). Proximal tephra F2 is unoxidized and is represented as the unoxidized portion of the Watana tephra in the mSRV, whereas oxidized proximal tephra H is represented as the upper oxidized portion of the Watana tephra in the mSRV. Indeed, archaeological investigations have occasionally noted eolian units or thin paleosols between the upper and lower portions of the Watana tephra, suggesting the deposit represents two volcanic events separated in time (Dixon and others 1985; Romick and Thorson 1983). Schiff and others (2008) also note two tephra beds in Bear Lake, south of Hayes Volcano, likely originating from Hayes Volcano (based on the presence of biotite), separated by 1.5 cm of gyttja and with a modelled basal age of 3940-4120 cal yr B.P. Bayesian models of calibration produced as part of this study suggest that deposition of proximal tephra F/unoxidized Watana and proximal tephra H/oxidized Watana could have occurred in rapid succession or been separated by a maximum of 380 years.\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2017) reports a magnitude of 5.400, bulk eruptive volume of 8.100 cubic km and a dense rock equivalent eruptive volume of 1.000 cubic km for the eruption.","StartYear":-1800,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":30,"StartQualifierUnit":"Years","EndYear":-1250,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":30,"EndQualifierUnit":"Years","Volcano":"Hayes","ParentVolcano":"Hayes","VolcanoID":"ak116","ParentVolcanoID":"ak116"},{"ID":3911,"Name":"Great Sitkin 3700 yBP","Description":"From Waythomas and others (2003): \"Pumice lapilli tephra deposit (Sandwich ash?).\"\r\nNote that Waythomas and others (2001) suggest that Moffett is the source of the Sandwich ash. Unclear whether this ash is indeed the Sandwich ash (i.e. erupted by Moffett and deposited on Great Sitkin), or an ash erupted by Great Sitkin and incorrectly thought to be the Sandwich ash.","StartYear":-1750,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-1450,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":2951,"Name":"Martin Lower Pale Tan Ash","Description":"From Fierstein and others (2007): \"Between the lower grey ash and ODLF marker beds (discussed above: K-2500J and H in this section) is a thin, discontinuous pale tan ash represented by sample K-2500i. Compositionally similar (only slightly more silicic) to the distinctive salt and pepper ash (K-2500K; Fig. 13 [in original text]), it seems likely that layer \"I\", also came from nearby Mount Martin, especially as this layer has not been found anywhere else. Layer \"I\", 6 cm beneath K-2500J, but 30 cm above K-2500H is slightly older than (our preferred age of) ∼3,600 14C year B.P., but probably much younger than ODLF, which has an age of ∼3,800-4,000 14C year B.P. Because ~400 14C years separates the lower grey ash from the ODLF unit, and the lower pale tan ash (\"i\") is about 1/6 the distance between them, the best estimate for a deposition time for this ash is ∼3,700 14C years B.P.\"","StartYear":-1750,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Martin","ParentVolcano":"Martin","VolcanoID":"ak189","ParentVolcanoID":"ak189"},{"ID":3221,"Name":"Veniaminof CFE","Description":"From Miller and Smith (1987): \"A 10-km-diameter, ice-filled summit caldera marks the top of Veniaminof volcano, a large (\u003e400 km3) andesitic stratocone (Fig. 1 [in original text]). Postglacial ash-flow sheets extend to 50 km from the caldera rim on the Bering Sea side of the volcano; on the Pacific Ocean side, ash flows apparently entered bays and estuaries.\"\r\n\"14C ages of 3640+/-200 yr and 3750+/-200 yr (samples 15, 16, Table 1 [in original text]) were obtained from charcoal in separate phases of an ash-flow tuff west of Veniaminof. These ages compare well with maximum 14C ages of 3620+/-80 yr (samples 17, 18, Table 1 [in original text]) from organic material underlying ash-flow tuff on the west flank of Veniaminof and of 3660+/-90 yr on organic material underlying distal air fall from the caldera-forming eruption. A date of about 3700 B.P., therefore, seems reasonable for the climactic eruption that formed Veniaminof caldera.\"\r\nFrom Waythomas and others (2015): \"Extensive, valley-filling pyroclastic flows on all flanks of the volcano extending 40-60 km beyond the caldera.\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2017) reports a magnitude of 6.7, bulk eruptive volume of 50 cubic km and a dense rock equivalent eruptive volume of 20 cubic km for the eruption.","StartYear":-1750,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Veniaminof","ParentVolcano":"Veniaminof","VolcanoID":"ak301","ParentVolcanoID":"ak301"},{"ID":2571,"Name":"Iskut-Unuk River cones 3660 yBP","Description":"From Hauksdottir and others (1994): \"Three cinder cones are identified (Fig. 2 [in original text]). The youngest cone lies to the south and appears to have fed the two youngest flows. It appears to have repeatedly erupted lava which dammed both Tom MacKay and Forrest Kerr creeks (B.C. Hydro, 1985). This inference is based on 14c dating of plant remains in lake sediments associated with these ephemeral dams. These age determinations (Table 1 [in original text], B.C. Hydro, 1985; Read and others, 1989) suggest lava effusion occurred 3800, 5600 and 6500-6800 years ago; the Iskut River Canyon was eroded to its present configuration in the last 3600 to 3800 years (B.C. Hydro, 1985).\"\r\nFrom Wood and Kienle (1990): \"Wood from a gravel lens in an upper group of light-colored flows yielded a C14 date of 3,660 yr BP.\"","StartYear":-1710,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iskut-Unuk volcanic field","ParentVolcano":"Iskut-Unuk volcanic field","VolcanoID":"ak136","ParentVolcanoID":"ak136"},{"ID":3781,"Name":"Redoubt Crescent River Lahars","Description":"From Beget and Nye (1994): \"At least two clay-rich mudflows, known as the Crescent River lahars, travelled 30 km down the Crescent River valley to the coast of Cook Inlet, buried an area of almost 90 km2 and had an original volume of more than 400 × 106 m3 (Riehle and others, 1981). Both lahars contain significant amounts of hydrothermally altered rock debris, have compact clayey matrices, and are generally olive-gray to yellow to red in outcrop. The upper lahar locally contains a component of fresh-appearing gray andesitic silt, sand, and granule size material. Wood fragments incorporated in the lahars are not burned, although some appear slightly charred on their outer edges. Prismatically jointed blocks are present in some exposures.\"\r\n\"The age of the Crescent River lahars can be closely determined. Small, isolated wood fragments in the lower lahar have previously been dated at 3605+/-145 and 3450+/-140 yr B.P. (Riehle and others, 1981). A large tree still in growth position but inundated and broken off 2m above its base by the lower lahar was exposed by wave erosion in 1990. Wood from the outer rings of this tree dates to 3620+/-70 yr B.P. (Table 1 [in original text]). If taken together and averaged, the three dates on wood from the lahars suggest an age for this deposit of 3589+/-58 yr B.P., while an average of the two apparently concordant dates yields 3617 +/-63 yr B.P. Thus, the lower Crescent River lahar appears to date to about 3600 yr B.P., corresponding to a calibrated age between 3963 and 3875 calendar years ago (Table 1 [in original text]). There is no soil development visible between the upper and lower lahar, and the contact is sharp and conformable at several excellent exposures in sea cliffs, which suggests that the upper lahar was deposited very soon after the lower lahar.\"","StartYear":-1695,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Redoubt","ParentVolcano":"Redoubt","VolcanoID":"ak231","ParentVolcanoID":"ak231"},{"ID":2711,"Name":"Kanaga T7","Description":"From Waythomas and others (2001): \"Groups of tephra deposits so defined indicate that at least 11 eruptions of Kanaga Volcano have occurred since about 11 ka. Most of these eruptions were probably sub-Plinian to Plinian, producing moderately vesicular dacitic pumice lapilli tephra deposits ranging in thickness from a few centimeters to more than 1 m (table 2 [in original text]).\"\r\n\"Sandy, pumice-lapilli fall deposit.\"","StartYear":-1679,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-1410,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kanaga","ParentVolcano":"Kanaga","VolcanoID":"ak144","ParentVolcanoID":"ak144"},{"ID":1871,"Name":"Augustine Shuyak Island Ash 3","Description":"From Waitt and Beget (2009): \"On Shuyak Island 110 km southeast of Augustine (fig. 1A [in original text])...a higher Augustine tephra there dates between 3,620 and 3,360 yr B.P. (table 2; plate 2, section RBW 93Ko.09 [in original text]) (tephras identified in Riehle and others, 1998).\"\r\nFrom Waitt and Beget (1996): \"On Shuyak Island 100 km south-east of Augustine, distal fall tephra of Augustinian chemical provenance (probe analysis of glass) dates between about 3620 and 3360 y B.P. (table 2 [in original text]; Riehle and others, 1996).\"\r\nFrom Waythomas and Waitt (1998): \"The oldest known distal volcanic ash from Augustine Volcano was deposited about 3600 yr B.P. on Shuyak Island, 100 kilometers southeast of Augustine Volcano (fig. 1 [in original text]; Waitt and others, 1996).\"","StartYear":-1670,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":25,"StartQualifierUnit":"Years","EndYear":-1410,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":25,"EndQualifierUnit":"Years","Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":2911,"Name":"Mageik Lower Grey Ash","Description":"From Fierstein (2007): \"From the vent at an elevation of 2,010 m, two of the flows extend 6 km to termini as low as 300-350 m in Martin Creek; we call these the \"south lobes\". One of the youngest flows bifurcates to the northeast; we call this the \"Y-flow\". The rim of the ice-filled crater on the East Summit is strewn with coarse scoriae and dense glassy blocks of phreatomagmatic ejecta, deposited upon the surfaces of thin lava flows exposed locally. Compositional data for one such ejecta block is used here to represent the \"East Summit\" in the following correlations.\"\r\n\"Considerable overlap in the microprobe data between the different East Mageik lavas and tephras (Fig. 23 [in original text]) preclude firm correlations, but we tentatively suggest...that lower TiO2 of magnetites and lower CaO of glass correlate the \"Y-flow\" with the lower grey ash (∼3,600 14C years B.P.)...\"\r\n\"The older grey ash, similar enough in thickness and color to the younger one that they are difficult to distinguish in the field, is only slightly coarser in the lower VTTS area (ash to 2 mm). In upper Windy Creek, however, they are clearly distinguishable. The older ash thickens and coarsens southward toward Mounts Mageik and Martin into a coarse lapilli fall more than 28 cm thick with largest clasts as big as 8 cm on top of pre-Holocene lava-flow benches at the northern foot of Mount Mageik (Fig. 8 [in original text]). From north to south, the unit coarsens from fine ash in the lower VTTS, to fine and medium ash along Windy Creek valley, to a slightly normally graded layer 5-to-10-cm thick with clasts as large as a centimeter in the upper reaches of the creek (Figs. 8, 9 [in original text]). There, the younger grey ash is still fine-grained and ∼1cm thick, but the older one coarsens to a sand+granule+lapilli fall very similar to (but slightly finer than) the \"orange dacite lapilli fall\" described below. Crystal proportions and micro- probe analyses of glass and Fe-Ti oxides were essential in distinguishing these fall layers. Even where both young ash layers are grey and fine-grained, their mineral proportions are distinctive, as the opx/cpx ratio of ∼2:1 in the lower ash is an order of magnitude smaller than that of the upper (∼20:1). Microprobe glass data also clearly distinguish the two, as the lower grey ash has much more silicic glass (∼74-78 wt.% SiO2) than the upper (59-67 wt.% SiO2; Fig.7 [in original text]).\"\r\n\"Preserved sections are too few to permit construction of well-constrained isopachs and isopleths, but the data do indicate a fairly narrow northeasterly dispersal (clasts as large as 4-8 cm are found near the foot of Mount Griggs; Fig. 8 [in original text]) and a source vent at either Mount Martin or East Mageik (the only Holocene vent on the Mount Mageik multi-vent stratovolcano). Glass and magnetite microprobe data for the lower grey tephra are similar to those for some of the youngest lava flows from both Martin and Mageik (Figs. 7, 10 [in original text]); although neither data set conclusively discriminates between those sources, the glass data favor Mount Mageik. The large pumice clasts (5 to 8 cm) and thick fallout (\u003e28 cm) so close to the Mageik vent also favors that edifice. Moreover, a younger tephra (less widely preserved, discussed in the next section) is linked to the youngest cone-building phase of Mount Martin, and we are aware of no other eruption of Martin young enough to have produced this \"lower grey ash\". Nine radiocarbon dates for soils above and below this fall layer bracket its deposition between ∼3,200 and 3,800 14C years (Table 2 [in original text]); stratigraphy and evaluation of the 14C dates favors∼3,600 14C years B.P.\"","StartYear":-1650,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mageik","ParentVolcano":"Mageik","VolcanoID":"ak187","ParentVolcanoID":"ak187"},{"ID":3181,"Name":"Yantarni 3500 yBP","Description":"From Riehle and others (1987): \"To summarize, our data indicate that most of the pyroclastic flows were emplaced after a debris avalanche of cone material from the northeast sector of Yantarni cone. Blocks of cone material as much as tens of meters across are incorporated in the lowermost pyroclastic-flow deposits, suggesting that the initial pyroclastic flows were partly contemporaneous with avalanching. Debris avalanches are commonly but not necessarily accompanied by directed explosions (Siebert, 1984). We have found a possible but ambiguous candidate for a directed-blast deposit at one site 8 km southeast of the cone. Thus, we conclude that the debris avalanche was caused or at least closely followed by magmatic eruptive activity, but we cannot prove that the avalanche was accompanied by a directed blast.\"\r\n\"Deposits of the debris avalanche and ensuing pyroclastic flows are certainly no older than Holocene by virtue of the absence of glacial erosion. The pyroclastic bed at site 58 that is provisionally correlated with the catastrophic eruption overlies silt with a radiocarbon age of about 2 ka (fig. 12 [in original text]). The radiocarbon age is a minimum, due to the presence of a trace amount of modern rootlets. Moreover, the pyroclastic bed lies atop silt (loess) that contains disseminated ash sized clasts of white, gray, and honey-colored pumice and black obsidian. Such disseminated ash closely resembles, in its proportions of colors, proximal tephra deposits of the caldera- forming eruptions of Aniakchak Caldera collected at a site 30 km southwest of Yantarni Volcano (Riehle, unpublished data). The age of the Aniakchak eruption is between 3.3 and 3.7 ka (Miller and Smith, 1977), and if the correlation with site 58 is valid, then the coarse pyroclastic bed is no more than about 3,500 yr old. Thus, we provisionally consider the catastrophic eruption to be no more than 3,500 yr old and possibly as young as 2,000 yr.\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2017) reports a magnitude of 5, bulk eruptive volume of 1 cubic km and a dense rock equivalent eruptive volume of 0.4 cubic km for the eruption.","StartYear":-1550,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-50,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Yantarni","ParentVolcano":"Yantarni","VolcanoID":"ak328","ParentVolcanoID":"ak328"},{"ID":2401,"Name":"Griggs 3460 yBP","Description":"From Fierstein (2007):\"Mount Griggs, fumarolically active and moderately productive during postglacial time (mostly andesitic lavas), has three nested summit craters, two of which are on top of a Holocene central cone. Only one ash has been found that is (tentatively) correlated with the most recent eruptive activity on Griggs (\u003c3,460 14C years B.P.).\"\r\n\"One tephra layer found on lower slopes of Mount Griggs (K-2419 in Griggs Fork of Knife Creek) may be correlative with lava from the innermost (youngest) crater at Griggs summit.\"\r\n\"Although Griggs has been moderately productive during postglacial time and is relatively better preserved than many stratovolcanoes in the region, only one tephra has been identified that correlates compositionally with Griggs lavas. Preserved in a gully at the south foot of the volcano, only 4 km SE of the summit, the ash includes magnetite with distinctively high TiO2 (12-15% TiO2) that is similar to magnetite from a small knob (that might be a 50-m-dome) within the innermost (and youngest) crater on Mount Griggs (Fig. 7b [in original text]). If this correlation is correct, the ash records the most recent eruptive activity on Griggs. A radiocarbon date on soil 4-7 cm beneath this ash is 3,460+/-40 14C years B.P.\"","StartYear":-1510,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":40,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Griggs","ParentVolcano":"Griggs","VolcanoID":"ak112","ParentVolcanoID":"ak112"},{"ID":1181,"Name":"Aniakchak CFE II","Description":"From Neal and others (2001): \"Modern Aniakchak caldera formed about 3,500 years ago during a violent, catastrophic eruption nearly 1,000 times the size (eruptive volume) of the August 1992 eruption of Mount Spurr volcano (fig. 1 [in original text]; Miller and Smith, 1977). During the caldera-forming eruption, draining of underground magma reservoirs caused an existing stratocone to collapse, thereby creating the deep crater that persists today (fig. 4 and pl.1 [in original text]). The enormous impact of this eruption is evident in thick blankets of coarse, pumice-rich debris deposited by pyroclastic flows that flowed in all directions from Aniakchak. These deposits extend as much as 60 km, to Bristol Bay and the Pacific Ocean. Fine ash from this eruption has been identified as far away as the north shore of the Seward Peninsula, 1,100 km to the north (Riehle and others, 1987, p. 19-22; Beget and others, 1992). Moreover, careful analysis of these fall-out deposits suggests that as many as 10 distinct, smaller explosive eruptions together spanned decades to centuries leading up to the climactic caldera-forming eruption (Riehle and others, 1999).\"\r\nFrom Bacon and others (2014): \"The spectacular 10-km-diameter Aniakchak Crater is a caldera that collapsed during the voluminous Aniakchak II eruption ca. 3,590 cal yr B.P. (ca. 3,430 14C yr B.P.). This eruption produced rhyodacite Plinian pumice fall and ignimbrite, followed first by ignimbrite with both rhyodacite and andesite juvenile clasts, then by andesite ignimbrite. The mixed and andesite ignimbrite deposits commonly are partly welded. Ignimbrite is present in valleys surrounding the edifice and extends to the coast on both northwest and southeast.\"\r\n\"The ignimbrite is significant for the high mobility of the pyroclastic flows that deposited it (Miller and Smith, 1977) and for dramatic compositional zonation of rhyodacite followed by andesite (Miller and Smith, 1977; Dreher, 2002; Dreher and others, 2005). Ash from this eruption has been identified over a large part of the Alaska Peninsula and on the Alaska mainland as far north as the Seward Peninsula (Riehle and others, 1987; Beget and others, 1992). The calendrical age of the eruption is suggested to be 3,590-3,588+/-11 cal yr B.P. (Coulter and others, 2012) by correlation with chemically analyzed glass shards associated with an acid spike in Greenland ice cores (Pearce and others, 2004; Denton and Pearce, 2006), which compares favorably with the calibrated +/-2 sigma age range of 3550-3870 cal yr B.P. and preferred +/-1 sigma age of 3,660+/-70 cal yr B.P. for 3,430+/-70 14C yr B.P. (table 1 [in original text]).\"\r\nFrom VanderHoek (2009): \"United States Geological Survey and NPS researchers have reported multiple lines of evidence that, when taken together, suggest a warm season eruption for the 3400 B.P. Aniakchak event. The first of these include a pattern of tephra fallout to the north-northwest (Beget and others 1992; Riehle and others 1987), indicating a wind from the south-southeast, which is more common in the region between May and September (Lea 1989b:227, Figure 5.3). Additional support for a warm season eruption is the fact that rip-up peat clasts were found entrained in the lower levels of the 3400 B.P. pyroclastic flow (Dilley 2000), suggesting flow over unfrozen ground. Third, a tsunami was generated by the pyroclastic flow striking Bristol Bay (Waythomas and Neal 1998), suggesting the flow encountered an unfrozen bay. Fourth, the tsunami deposits on the northern Bristol Bay coast also contained rip-up peat clasts (Waythomas and Neal 1998: 112), which would only have happened if the tsunami swept across the northern coast when the ground was unfrozen.\"\r\nFrom Derkachev and others (2018): \"Glass from the Br2 tephra have medium-K rhyolitic compositions and are geochemically similar to the rhyolitic population of the ~ 3.6 ka Aniakchak II glass (Kaufman et al. 2012; Davies et al. 2016; Wallace et al. 2017) (Figs. 5, 6,and 7) [in text]. Only one of the analyzed Br2 shards falls into the andesitic Aniakchak II field; however, non-analyzed brown shards described in the samples likely indicate the presence of the whole andesite Aniakchak II population. Moreover, rhyolite Br2 glass are identical in composition to rhyolite glass from both proximal and ultra-distal (Chukchi Sea) Aniakchak II tephras. A single andesitic glass shard analyzed by LA-ICP-MS has a very similar trace element composition to that of andesitic Aniakchak II shards from Chukchi Sea sediments (Fig. 4a) [in text]. \r\nBased on chemical similarity of Br2 glass to those from the 3.6 ka Aniakchak II tephra, its Holocene age (Fig. 2) [in text], and the aerial distribution of the Aniakchak II fall deposit (Davies et al. 2016; Graham et al. 2016; Pearce et al. 2017; Ponomareva et al. 2018), we suggest that the Br2 tephra correlates to the ~ 3.6 ka Aniakchak II eruption. A preliminary report on this finding by Derkachev et al. (2015) permitted Ponomareva et al. (2018) to use this site to develop a new isopach map for the Aniakchak II tephra fall deposit. The new map allows us to double the volume of this eruption from the value of 50 km3 given by Miller and Smith (1987) to~100 km3. Assuming an ash density of 0.6 g/cm3 (Kutterolf et al. 2008b) and rhyolite density of 2.6 g/cm3, the dense rock equivalent (DRE) volume of the Aniakchak II tephra fall deposit is here estimated to be 23 km3,with an erupted mass of 6.0 × 104 Mt. This corresponds to an eruption magnitude (M) of 6.8 (Pyle 1995; Mason et al. 2004). \r\nWide dispersal of the ~ 3.6 ka Aniakchak II tephra across the Bering Sea (Derkachev et al. 2015; Graham et al. 2016) permits significant enlargement of its known dispersal area (Davies et al. 2016) and indicates that it could also occur in northeast Asia (Fig. 1) [in text]. The Aniakchak II tephra can also serve as a major Holocene marker horizon for the Bering Sea shelf, directly linking its Holocene sedimentary archives to those from the Chukchi Sea (Pearce et al. 2017; Ponomareva et al. 2018), eastern Canada (Pyne-O'Donnell et al. 2012), and Greenland (Pearce et al. 2004; Coulter et al. 2012; Jennings et al. 2014).\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2016) reports a magnitude of 6.9, bulk eruptive volume of 75 cubic km and a dense rock equivalent eruptive volume of 33.5 cubic km for the Aniakchak II eruption.","StartYear":-1480,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":70,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":3821,"Name":"Redoubt Northfork Lahars","Description":"From Beget and Nye (1994): \"Several lahars, tephra layers, and beds of alluvium separated by peat layers and thin soils are exposed in 10-30-m-high streamcuts along the North Fork of the Crescent River. These deposits record eruptions of Redoubt Volcano that are younger than the Crescent River lahars and that strongly affected the upper parts of the Crescent River drainage. We refer to this newly recognized set of deposits as the North Fork lahars (Fig. 1 [in original text]).\"\r\n\"Together these laharic deposits form a flat-topped valley fill that occupies virtually the entire upper Crescent River valley. The surface gradient of the valley fill is about 0.01-0.02 near the confluence of the Lake Fork and the North Fork of the Crescent River; when traced upvalley it merges into a steeper fan with a gradient of as much as 0.2 that debouches from the central of three valleys on the southwest flank of Redoubt Volcano. This valley directly drains the summit region of Redoubt Volcano, and was apparently the primary source of the North Fork lahars, although some of the material may have come down the other valleys from the summit of Redoubt Volcano.\"\r\n\"Numerous exposures through the valley fill expose as many as 4-6 separate yellow to gray lahars composed primarily of fresh lithic fragments. These monolithic lahars are typically 1-3 m thick (Figs. 9, 10 [in original text]). The North Fork lahars typically have a coarse sand-sized matrix and contain many andesitic clasts 50-100 cm or more in diameter, and so are much more coarse grained than the clay-rich lahars found downstream. One thick lahar exposed for several kilometers in stream cuts near the confluence of the North Fork and Lake Fork contained numerous prismatically jointed blocks, which were apparently hot when emplaced. Some clasts in this lahar had reddish hydrothermally altered rinds, while others were surrounded by rings of reddish hydrothermal alteration in the enclosing fine-grained lahar sediment. We believe this lahar consisted in part of still-hot pyroclastic flow debris or collapsed dome rocks. The other lithic lahars exposed along the upper Crescent River probably also consist largely of reworked pyroclastic debris, although evidence of heat is only rarely encountered.\"\r\n\"At least three sets of deposits of younger alluvium, lahars, and tephra can be recognized above the sequence of thick lahars (Figs. 9, 10 [in original text]). The upper thin lahars also appear to be monolithologic, and contain matrix-supported clasts as much as 20-50 cm in diameter, and consist almost entirely of gray andesite. These sediments resemble deposits laid down in the lower Drift River valley during the 1966 and 1989-1990 eruptions, and may have been produced when small pyroclastic flows were emplaced over snow and glaciers. Radiocarbon dates of 2080+/-60 and 1840+/-50 yr B.P. on peat layers interbedded with the youngest lahars in the upper Crescent river valley suggest that eruptions affected the Crescent River valley for almost two thousand years after the time of the Crescent River lahars. Radiocarbon dates of 1630+/-70, 2230+/-60, 2270+/-70, 2930+/-60, 3120+/-60, 3320+/-70, 3410+/-60 yr B.P. on peat adjacent to tephra layers of fine to medium lapilli exposed in coastal bluffs 30 km east of Redoubt Volcano also show that pyroclastic eruptions continued for more than 1800-2000 years after the time of the Crescent River lahars (Table 1 [in original text]). The base of the North Fork lahar sequence is not exposed anywhere along the upper river, but the two clay-rich Crescent River lahars exposed in beach cuts 20 km downstream presumably underlie the multiple North Fork lithic lahars found nearer to the volcano.\"","StartYear":-1460,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":60,"StartQualifierUnit":"Years","EndYear":320,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":70,"EndQualifierUnit":"Years","Volcano":"Redoubt","ParentVolcano":"Redoubt","VolcanoID":"ak231","ParentVolcanoID":"ak231"},{"ID":3511,"Name":"St. Paul Island 3230 yBP","Description":"From Barth (1956): \"Between Fox Hill and the west coast is a rather extensive lava field with a magnificent display of miniature volcanic forms: a multitude of hornitoes, chimneys with foam and splatters, blowholes, diatremes, and miniature craters.\"\r\nFrom Winer and others (2004): \"The youngest monogenetic volcano is Fox Hill and its associated lava flow, which yielded a 14C date of 3230+/-40 years BP.\"\r\n\"The Fox Hill eruptive center is an elongate complex of four overlapping, breached scoria cones and an associated lava flow that extends 3.5 km to the sea at Southwest Point (Fig. 2 [in original text]). The Fox Hill cones are breached to the southeast, perpendicular to the north-east-southwest trend of its multiple aligned vents. Greater than half of the cone complex is missing, although thousands of chunks of fairly well consolidated scoria and partially welded spatter of varying sizes (up to 4 m thick) are present on the surface of the lava flow along its entire length. The lava flow is morphologically young with well-preserved marginal levees and interior flow channels. Compared with older lava flows on the island, the Fox Hill lava flow has much less eolian sediment cover and vegetation. The lava flow appears to be unfaulted.\"\r\n\"Due to the young age and lack of significant erosion and burial by younger deposits, the Fox Hill lava flow permits estimation of the volume of lava flows associated with monogenetic volcanoes on St. Paul Island. The average thickness of the flow is 3.25 m at Southwest Point where it is well exposed in cross-section in sea cliffs and its area is approximately 2km square. Therefore, allowing for lava that ran into the sea or eroded from the sea cliffs, the minimum estimate for the volume of the Fox Hill lava flow is ~0.01 km cubed.\"\r\n\"The Fox Hill scoria cone complex is interpreted to have formed during a Strombolian-style eruption from multiple, closely spaced vents that localized along a Northeast-southwest striking fissure. Wholesale breaching of the southeast wall of the complex probably occurred with waning of the explosive phase and eruption of more dense, volatile-poor lava. Chunks of the breached cone wall rafted away on lava flow lobes that issued from as many as four individual, but related, vents. Pronounced levees along flow margins indicate that the volumetric flow rate for the lava flow was high (\u003e5-10 m cubed/s; Rowland and Walker, 1990).\"","StartYear":-1280,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":40,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"St. Paul Island","ParentVolcano":"St. Paul Island","VolcanoID":"ak264","ParentVolcanoID":"ak264"},{"ID":3411,"Name":"Sajaka Two, Sajaka One","Description":"From Jicha and others (2012): \"Sajaka is the westernmost center of the Tanaga volcanic cluster and the least silicic of the Holocene volcanoes. All analyzed lavas contain less than 51 wt% SiO2. Sajaka One is a truncated stratocone mantled by thick fall deposits from Tanaga and Sajaka Two. A columnar-jointed basalt from near the top lavas along the southern shoreline yielded a 40Ar/39Ar age of 3.2+/-4.7 ka. Nearly the entire western half of Sajaka One was destroyed by a sector collapse directed to the west. The resultant submarine debris-avalanche deposit is visible in multibeam bathymetry (Coombs and others, 2007a) and extends at least 9 km offshore but is not preserved on the island. This collapse appears to have been contemporaneous with the emplacement of pyroclastic-flow deposits along the northern contact between Sajaka One and Sajaka Two (Fig. 5D [in original text]). The pyroclastic-flow deposit (unit sop) is up to 60 m thick and contains ~70% lithic lapilli and ~30% scoria lapilli in a crystal-rich, ash matrix. The 290-m-high wall created by the sector collapse consists of thin (\u003c1 m to 2 m) Sajaka One lavas, scoria-fall deposits, and lithic-rich pyroclastic-flow deposits.\"\r\nFrom Coombs and others (2007): \"Sajaka’s eruptive history can be broken into two parts. Sajaka One started to grow several thousand years ago, forming a cone likely to have been similar to those of Tanaga and East Tanaga. The eastern half of the Sajaka One edifice is still intact, but the western half is missing (fig. 11 [in original text]). A new, younger cone (Sajaka Two) has grown in the scar. The removal of Sajaka One’s western half probably was caused by a landslide. Recent bathymetric mapping of the seafloor west of Sajaka revealed a debris field with several large blocks in the areas within the failure scarp of Sajaka One (Coombs and others, 2007). On land, no debris-avalanche deposit has been recognized, but outcrops of a pyroclastic-flow deposit were detected on top of Sajaka One lava. The presence of the pyroclastic-flow deposit indicates the collapse may have been accompanied by an explosive eruption, or possibly a lateral blast (Siebert, 1984). The lower part of the Sajaka One amphitheatre is obscured by the new Sajaka Two cone; however, the upper reach of the Sajaka One edifice is truncated by a 1.5-km-diameter crater that resembles those at Bezymianny, Russia, and Mount St. Helens, Washington, other volcanoes that have experienced lateral blasts (fig. 6 [in original text]). The age of the Sajaka One collapse is thought to be a few thousand years ago, because lava from beneath the pyroclastic-flow deposit and from the Sajaka Two cone yield radiometric ages of 5,000 years to present.\"\r\nFrom Coombs and others (2007): \"The earlier edifice, Sajaka I, was truncated nearly in half, with a new, younger cone (Sajaka II) growing in the scar. The resulting debris-avalanche deposit is now below sea level, but limited subaerial exposures show a pumiceous pyroclastic flow deposited on Sajaka I lavas. The presence of the pyroclastic-flow deposit suggests that this sector collapse may have been accompanied by an explosive eruption. The lower part of the Sajaka amphitheatre is obscured by the new cone, but the upper reach of the Sajaka I edifice is truncated by a 1.5-km-diameter crater that resembles those at Bezymianny and Mount St. Helens, where landslides were accompanied by eruptions as pressure was released on shallow magmatic intrusions [41].The age of the Sajaka collapse is late Holocene, because lavas from beneath the pyroclastic-flow deposit and from the Sajaka II cone yield 40 Ar/ 39 Ar ages of 5-0ka(A. Calvert, unpublished data).\"","StartYear":-1250,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":4700,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Sajaka Two","ParentVolcano":"Tanaga","VolcanoID":"ak241","ParentVolcanoID":"ak280"},{"ID":2821,"Name":"Koniuji 3100 yBP","Description":"From Jicha (2009): \"Lavas and domes from a 3.1 ka and younger andesitic complex represent the latest major phase of activity on the island are the most evolved.\"\r\n\"An angular block from within the hornblende bearing andesitic dome complex yielded a 40Ar/39Ar age of 3.1+/-1.9 ka. A single experiment on sample KON-07-05, a hornblende andesite collected at 177 m above sea level from near the center of the island, failed to yield a significant amount of radiogenic 40Ar. This sample likely represents the youngest part of the hornblende andesite unit and erupted within thelast three millennia.\"","StartYear":-1150,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":1900,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Koniuji","ParentVolcano":"Koniuji","VolcanoID":"ak168","ParentVolcanoID":"ak168"},{"ID":3611,"Name":"Makushin 3030 yBP","Description":"From Bean (1999): \"One date under a lahar at site 96MAK11 suggests that it may have been deposited shortly after 3030 14C yr B.P.\"","StartYear":-1080,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":70,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":1501,"Name":"Buzzard Creek Maars","Description":"From Andronikov and Mukasa (2010): \"Two Buzzard Creek maars located next to the upper stream of Buzzard Creek, along the northern foothills of the central Alaska Range are surrounded by tuff rings which are ∼300 m and ∼70 m in diameter. The volcanic rocks are represented by two main types: volcanic ejecta consisting of small volcanic lapilli (1-5 cm in diameter) and volcanic bombs with a mixture of host rocks fragments, and basaltic lavas. Radiocarbon dates from charcoal samples above and below the basaltic ejecta give an eruption age of ca. 3000 years (Wood and Kienle, 1990; Nye, 2006, pers. comm.). Although volcanic rocks of the Buzzard Creek maars are insignificant in volume, they are interesting tectonically because they occur in a 400 km volcano gap between the Aleutian arc structure and Wrangell Volcanic Field (Richter and others, 1990; Miller and Richter, 1994), and are situated over the northernmost corner of the subducting Pacific Plate.\"\r\n\"Buzzard Creek basalts are dark-grey to brownish-black rocks composed of plagioclase (20-25%), augite (3-5%) and olivine (5-10%) phenocrysts in a fine- to medium-grained groundmass consisting of elongated plagioclase microlites (10-15%), clinopyroxene laths (5-10%), small olivine grains (10-15%), with scattered euhedral magnetite crystals (5-10%), and brownish glass (5-10%). The lavas are often vesicular, and many vesicles have been partially filled by zeolites. Apart from this, the rocks are generally fresh and unaltered. Tiny (up to∼1 cm) spinel lherzolite xenoliths and xenocrysts of Cr-spinel, olivine and Cr-diopside, that are likely disaggregations of the spinel lherzolite xenoliths, are common in the Buzzard Creek lavas. Ejecta lapilli are compositionally similar to the basaltic lava, but contain abundant fragments of the host crustal rocks as well as mantle microxenoliths and xenocrysts often serving as the points of nucleation for the lapilli.\"\r\n\"Wood and Kienle (1990) reported that the Buzzard Creek maars erupted as recently as 3000 years ago. To verify this [Andronikov and Mukasa, 2010] analyzed lava sample 05BZC-1, obtaining 40 Ar/39 Ar ages of -0.12+/-0.06 Ma (plateau), 0.01+/-0.07 Ma (isochron), and -0.02+/-0.06 Ma (total gas) (Fig. 4 [in original text]) which verifies a very young eruption age although the measurements did not yield a usable absolute value.\"","StartYear":-1050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Buzzard Creek","ParentVolcano":"Buzzard Creek","VolcanoID":"ak35","ParentVolcanoID":"ak35"},{"ID":2921,"Name":"Mageik Upper Pale Tan Ash","Description":"From Fierstein (2007): \"From the vent at an elevation of 2,010 m, two of the flows extend 6 km to termini as low as 300-350 m in Martin Creek; we call these the \"south lobes\". One of the youngest flows bifurcates to the northeast; we call this the \"Y-flow\". The rim of the ice-filled crater on the East Summit is strewn with coarse scoriae and dense glassy blocks of phreatomagmatic ejecta, deposited upon the surfaces of thin lava flows exposed locally. Compositional data for one such ejecta block is used here to represent the \"East Summit\" in the following correlations.\"\r\n\"Considerable overlap in the microprobe data between the different East Mageik lavas and tephras (Fig. 23 [in original text]) preclude firm correlations, but we tentatively suggest that the…higher MgO of magnetite correlates the upper pale tan ash with the East Mageik Summit (∼2,600 14C years B.P.).\"\r\n\"Separated from the mica-bearing ash (K-2500M) by another 15.5 cm of dark peaty soil is a 1-cm layer of pale tan ash (K-2500L). This ash is preserved farther upstream in Angle Creek (K-2498; Fig. 2 [in original text]) and in two additional key sections (Fig. 3 [in original text]), including atop the Martin coulees and in Mageik Creek (K-2197), where it is as much as 5 cm thick, 10 km ESE of the East Mageik crater (Fig. 2 [in original text]). These thicknesses suggest the tephra came from East Mageik, which is consistent with glass data that shows complete overlap with the two older Mageik ash layers (the lower grey ash and ODLF) represented in this section by K-2500 J and H (Fig. 13 [in original text]). Because sample K-2500L is halfway between K-2500 M and J (which brackets its age in this section between 2,310 and 3,355 14C year B.P.), our best estimate for deposition of the upper pale tan ash layer is ∼2,600-2,900 14C year B.P., favoring the younger extreme.\"","StartYear":-950,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":-650,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mageik","ParentVolcano":"Mageik","VolcanoID":"ak187","ParentVolcanoID":"ak187"},{"ID":2961,"Name":"Martin Salt and Pepper Ash","Description":"From Fierstein (2007): \"Only a few centimeters beneath the upper pale tan ash is another sharply defined and persistent pale tephra 0.5-cm thick (K-2500K in this [Angle Creek] section). Distinctive in glass composition (∼71-72 wt.% SiO2, CaO ∼1.5-1.8 wt.%) and yielding microprobe data that plot in a tight group (Fig. 13 [in original text]), this sandy layer (Md=0.35 mm; Table 1 [in original text]) is similarly coarse eastward (Md=0.34 mm) and thickens to 7 cm atop the Martin coulees (K-2661C; Figs. 3, 14 [in original text]) only 3 km SE of section K-2500. It apparently thins eastward from there, however, being only 3 cm thick in the headwaters of Angle Creek and 0.5 to 1 cm thick in the lower VTTS (K-2675; Figs. 3, 14 [in original text]). Both thickness and clast-size data point to Mount Martin as the source for this fallout. Most noteworthy of the maximum clast data in Fig. 14 [of original text] are the 1-to-1.7-cm lithics in the fall layer at the head of Angle Creek. One of the most distinctive aspects of this tephra is its \"salt and pepper\" look in the field. Not only is it crystal rich with pyroxenes (opx and cpx) and feldspars contributing this dark and light coloring, but it also includes a mixture of white-to-clear glass and distinctive dark brown to black, granular and friable lithic clasts. These lithics, similar in appearance to those in the mica-bearing ash, are loosely coherent crystal sand, with dark-light stratification evident in some of the larger clasts. Likely to be a sort of tuff deposit at the vent disrupted by the ash eruption, these lithic clasts-although not a unique lithology, are distinctive-add a useful identifying criterion for this tephra layer. Only in Angle Creek section K-2500 do the brown-black granular clasts (up to 8 mm in size) make up much of the sample; at the head of Angle Creek, although these tuffaceous clasts are present, the predominant lithics are the denser bedrock (Jurassic Naknek) siltstone. At other more distal locations sampled, white fibrous pumiceous granules are the dominant component, with only minor amounts of the tuffaceous lithics.\"\r\n\"At all three locations with microprobe data, the glass plots in a tight group distinctively less silicic than all the tephras from Mount Mageik (e.g., lower grey and ODLF) and more silicic than those thought to be from Mount Peulik (e.g., upper grey; Fig. 13a [in original text]). FeTi-oxide data from these same three samples are less definitive, however, especially because some of the magnetite may have been derived from the friable, tuffaceous lithics; K-2500K has a bimodal distribution of low and high-MgO magnetite (2.2 wt.% and 4.2 wt.% MgO), K-2675A has magnetite that spans that entire range, and K-2661C has magnetite restricted to ∼2.2 wt.% MgO (Fig. 13b [in original text]). Of note is that this range of magnetite compositions is similar to that from other tephra layers suggested here to have been derived from Mount Peulik (upper grey ash, mafic orange fine ash, and mafic crystal ash). Relatively coarse grain size and thickness distribution, however, preclude Mount Peulik as a source for this ash layer. Instead, this tephra may have erupted during growth of the summit-forming ejecta cone (∼59-61 wt.% SiO2) that caps the stubby dacite lava flows high on Mount Martin (∼64 wt.% SiO2; Figs. 7, 8 in Fierstein and Hildreth 2001), which are in turn perched atop the older major mid-Holocene sprawling dacite coulees in Angle Creek (∼60-63 wt.% SiO2). 14C ages for soils loosely bracket the \"salt and pepper\" ash (\"K\" in section K-2500 in original text) between 2,310+/-120 and 3,355+/-135, and soil directly beneath the ash atop the Martin coulees (section K-2661 in original text) yields 2,700+/-100 and beneath the ash in upper Angle Creek (K-2069) yields 2,515+/-195. On this basis, and considering that the upper pale tan ash was also deposited during this interval, the favored deposition time for the salt and pepper ash is between 2,700 and 2,800 14C years B.P.\"","StartYear":-710,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":130,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Martin","ParentVolcano":"Martin","VolcanoID":"ak189","ParentVolcanoID":"ak189"},{"ID":2581,"Name":"Iskut-Unuk River cones 2555 yBP","Description":"From Hauksdottir and others (1994): \"The Lava Fork volcanic centre comprises basaltic ash and at least three flows, which are exposed at the confluence of Blue River and Unuk River...A layer of basaltic cinder and glassy ash covers the lava flows as well as the area to the east towards Leduc Glacier and Twin John Peaks (Grove, 1986).\"","StartYear":-605,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":60,"StartQualifierUnit":"Years","EndYear":-585,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":75,"EndQualifierUnit":"Years","Volcano":"Iskut-Unuk volcanic field","ParentVolcano":"Iskut-Unuk volcanic field","VolcanoID":"ak136","ParentVolcanoID":"ak136"},{"ID":2931,"Name":"Mageik 2500 yBP","Description":"From  Fierstein (2007): \"One of the youngest preserved ash layers from Mageik, represented only by K-2198 in Mageik Creek, is also compositionally similar to the Y-flow, but is a few hundred years younger (∼2,500 14C years B.P.).\"\r\n\"This section [the Mageik Creek section of Fierstein, 2007] has some regionally familiar players: the uppermost two pre-1912 tephras are the young grey ash (from Peulik?) and below it is a distinct yellow-tan very fine to fine ash layer correlated here with the mica-bearing ash (from Gas Rocks?). The lowermost pair of ash layers is correlated with two Mageik tephras (upper pale tan and lower grey ash layers). Between these pairs are two additional ash units. The lower of the two (sample K-2198) is an irregular 0.5- to 1-cm thick dark-grey fine crystal ash layer (plag+cpx+opx+mt; no ol). Glass shards (as seen by electron microprobe) tend to be very frothy with thin, stretched bubble walls. This has not been correlated with layers in other nearby sections, but lack of olivine precludes a source from Mount Griggs, the phenocryst assemblage and the glass and magnetite microprobe data are consistent with young East Mageik lavas, and it is sandwiched between young ash layers between ∼2,600 and 2,300 14C year B.P. Thus, this tephra is suspected to have been derived from Mount Mageik and, if so, is one of the youngest preserved ash layers from that edifice (favoring ∼2,500 14C year B.P.).\"","StartYear":-550,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mageik","ParentVolcano":"Mageik","VolcanoID":"ak187","ParentVolcanoID":"ak187"},{"ID":2491,"Name":"Iliamna 2400 yBP","Description":"From Wathomas and others (2000): \"The upper lahar deposit in West Glacier Creek Valley (L2, Fig. 15 [in original text]) contrasts markedly with the underlying lahar deposit L1, because hydrothermally altered rocks make up more than 80 percent of the clasts in L2 and impart a distinctive yellow-brown color (10YR4/6) to the deposit. Lahar deposit L2 is also a massive, matrix-supported diamict, and about 90 percent of the clasts are angular and subangular. The matrix of lahar deposit L2 is slightly sticky and plastic when wet or moist, indicating the presence of clay. However, the one sample analyzed for particle-size distribution contained only about 1 percent clay and 2 percent silt (Table 4 [in original text]) and we do not believe that this sample is truly representative of the matrix texture. Soil organic matter from a soil developed on top of lahar deposit L2 yielded a radiocarbon age of 1390+/-75 yr BP (Table 3 [in original text]) and this is also a mini- mum-limiting age for the lahar deposit. \r\n\"Because of its slightly cohesive texture and clast composition, deposit L2 could be a cohesive lahar that evolved from a debris avalanche on the southwest fank of Iliamna Volcano 1300-2400 yr BP. We are uncertain if L2 is related to an eruption of Iliamna Volcano.\"","StartYear":-450,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":650,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":2941,"Name":"Mageik Ferrocreted Ash","Description":"From Fierstein (2007): \"In contrast with the East Mageik Summit crater, the ice free fumarolically active crater between the East and Central Mageik Summits has no juvenile ejecta and is not magmatic. This 250-m-wide phreatic crater (Fenner 1930; Hildreth and others 2000) contains an acid lake and many superheated fumarolic jets. The \"ferrocreted layer\" (described above in the \"Mageik Creek section (K-2196): six pre-1912 tephras\") is the youngest ejecta layer identified from Mount Mageik and most likely marks initiation or development of this phreatic vent between 2,400 and 2,500 14C years BP. This tephra layer directly overlies (and fills interstices on the surface of) the south lobes from East Mageik (see Fig. 15 [in original text]).\"\r\n\"The youngest preserved ejecta from Mount Mageik, 15 cm above the crystal-rich ash (just described), is informally called the \"ferrocreted\" layer, here 5 cm thick. As thick as 7 to 15 cm on the Mageik lava bench near Katmai Pass (section K-2547C), and ∼4 cm thick (but irregular to 13 cm) at the foot of Mount Griggs (section K-2244; Fig. 15 [in original text]), it is typically a slightly normally graded, poorly sorted, fine to coarse ash and granule tephra. At all locations most clasts are coated orange to rusty dark orange-red, the deposits include hydrothermally altered clasts, and in Katmai Pass and the Griggs Fork are ferrocreted to some degree. In Mageik Creek, 5 cm of the \"soil\" directly underlying the ash is red. Dense clasts to 0.5 cm are found in Mageik Creek (sample K-2199), but they are as big as 3 cm near Katmai Pass, including white- to-pink hydrothermally altered lava clasts and light grey, glassy, finely vesicular crystal-rich lava (plag+cpx±opx, no olivine). Stratigraphic correlations of other tephra layers in these sections from Mageik Creek to Katmai Pass to the Griggs Fork (Fig. 15 [in original text]) corroborates that these \"ferrocreted deposits\" are all at the same stratigraphic horizon and record a single phreatic episode. In Mageik Creek, the ferrocreted layer lies 15 cm beneath the mica-bearing ash (2,310+/-120 14C years B.P.) and 15 cm above the young Mageik tephra just described (K-2198; ∼2,500 14C year B.P.), suggesting that the phreatic event was ∼2,400 14C years B.P. Clast size, deposit thickness, and glassy plag+cpx± opx lava clasts point to Mount Mageik as the source. This is the youngest recognized ejecta layer from Mageik, and it seems most likely to record initiation of the still-steaming phreatic crater just west of the East Mageik summit vent (Photo of phreatic crater in Hildreth and others 2000, Fig. 5 [in original text]).\"","StartYear":-450,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mageik","ParentVolcano":"Mageik","VolcanoID":"ak187","ParentVolcanoID":"ak187"},{"ID":2481,"Name":"Iliamna 2360 yBP","Description":"From Wathomas and others (2000): \"Lahar deposits in the valley of West Glacier Creek downstream from Umbrella Glacier (location UG-1, Fig. 14 [in original text]) are evidence that lahars have inundated this valley at least twice in the past 2300 yr. An older lahar deposit (L1, Fig. 15 [in original text]) is a massive, matrix-supported, dark-yellow brown (10YR 3/6) diamict, containing cobble-to-boulder-size clasts of andesite and minor amounts (\u003c20%) of hydrothermally altered rock. The majority of the clasts in the lahar deposit are subangular to angular. Ten to twenty percent of the clasts in lahar deposit L1 are rounded to subrounded and were likely entrained from the streambed as the lahar advanced downstream. A buried soil is developed on the surface of lahar L1 (Fig. 15 [in original text]) and soil organic matter from the soil yielded a radiocarbon age of 2360+/-80 yr BP (Table 3 [in original text]), a minimum-limiting age for inundation of the valley by lahar.\"\r\n\"Although we found no juvenile material in either lahar deposit, we interpret lahar deposit L1 as a noncohesive lahar that may have formed during an eruption of Iliamna Volcano about 2400 yr BP.\"","StartYear":-410,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":80,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":4081,"Name":"Kanaga Yellow Brown Olive Ash","Description":"From Kiriyanov and Miller (1987): \"Ad-2 has a thickness ranging between 1 and 5 cm and consists of a yellowish-gray silt- and clay-size material and a small amount of fine-grained sand. Distinctive features of this ash are the small glass content (33-55%), a considerably large plagioclase content (24-28%) and 8-10% lithic debris. In addition to pyroxenes, the ash also contains green (9%) and brown (6%) hornblendes. The inferred age of the ash is 2300 14C years.\"","StartYear":-350,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kanaga","ParentVolcano":"Kanaga","VolcanoID":"ak144","ParentVolcanoID":"ak144"},{"ID":1221,"Name":"Aniakchak Postcaldera Subaqueous Domes","Description":"From Bacon and others (2014):\"Cream-colored dacite pumice fall is exposed locally in cutbanks beyond the north flank of Aniakchak volcano. Soil from beneath this deposit 18 km north-northwest of the caldera at ~200 ft (60 m) elevation yields an age of 2,130+/-40 yr B.P., whereas organic sediment from beneath the deposit 14 km north of the caldera at ~300 ft (30 m) elevation gives an age of 2,300+/-80 yr B.P. (table 2 [in original text]). The weighted mean of these ages is 2,160+/-40 yr B.P. (table 1 [in original text]), but the large MSWD leads us to prefer the older of the two for a provisional age of ca. 2,300 yr B.P. The composition of a sample of pumice clasts (NA9413) does not exactly match that of any potentially correlative unit within the caldera but nevertheless is rather similar to that of West Dome. We [Bacon and others] tentatively consider the ca. 2,300 yr B.P. pumice fall to be the product of an explosive eruption within the caldera that preceded or possibly was contemporaneous with emplacement of the subaqueous domes that are described next.\"\r\n\"Within Aniakchak caldera, the oldest known products of postcaldera volcanism are four lava domes that were effused in a caldera lake. Relative ages of informally named Pumice, West, Vulcan, and Bolshoi Domes (fig. 10A [in original text]) are unknown. Pumice Dome is the most chemically evolved, two analyzed samples having 67.2 and 67.7 weight percent SiO2. Single samples from Vulcan and West Domes are compositionally similar at 65.6 and 65.8 weight percent SiO2, respectively, while a sample from Bolshoi Dome has 64.2 weight percent SiO2. The virtually identical compositions of the samples from Vulcan and West Domes suggest that they were emplaced at about the same time.\"\r\n\"Morphologies and surface features of the domes and the glassy character of the dacite lavas indicate that they were emplaced in water. The surface of Pumice Dome, poorly exposed other than in gullies and facing Surprise Lake, consists of pumiceous dacite in pillow-like forms ~0.3-2 m across (fig. 11A [in original text]) that are atypical of subaerial silicic lava but are consistent with extrusion into standing water. The surfaces consist of frothy, friable, light gray to white pumice characterized by cm-scale radial fracturing and irregular jointing (Allen and McPhie, 2000). Vugs as large as 20 cm across occur within pillows. Interstitial material is also pumiceous, banded, and radially fractured. West, Vulcan, and Bolshoi Domes are conical mounds of dacite vitrophyre whose flanks are coated by talus composed of finely vesicular to dense, polygonal joint blocks shed from outcrops on their upper portions. Outcrops on these three domes have fracture patterns (figs. 11B-F [in original text]) that are characteristic of chilling of degassed lava effused in water (see, for example, Goto and McPhie, 1998). Many structures and fracture patterns in lava flows and domes emplaced in contact with melt water within glaciers or adjacent to glacial ice (Lescinsky and Fink, 2000; Sporli and Rowland, 2006) closely resemble those in the domes at Aniakchak. Although hyaloclastite or breccia carapaces are not evident, 2-3-cm-thick patches of gray, sandy, and partially indurated tuffaceous sediment are found in pockets on the summit of Vulcan Dome. Thick glacial ice probably was not present at any time in the post-Aniakchak II caldera, whereas a deep intracaldera lake must have existed when the dacite domes were emplaced.\"\r\n\"Rhyodacite lava high on the northwest flank of Aniakchak volcano (fig. 4 [in original text]; labeled NW lava flow) is compositionally identical to a thin lava flow exposed within the caldera at ~2,500 ft (760 m) asl 1.5 km to the south, high in the west wall of the 1931 Main Crater (fig. 10 [in original text]; see also \"Geochemistry\" section [in original text]), above the level of any possible caldera lake. Little tephra is present and no Aniakchak I or II bombs have been reported on the blocky surface of the northwest lava flow where it has been examined, consistent with the flow being younger and similar in age to the lava in the caldera. The source of the intracaldera lava flow is unknown but appears to have been high on the caldera wall just inside the rim. The vent for the northwest flank flow must have been at ~2,400 ft (730 m) asl, 600 m west-northwest of the caldera rim. On the basis of their composition and apparent post-Aniakchak II age, these two flows are thought to have been approximately contemporary with Pumice Dome.\"\r\n\"Products of the earliest recognized postcaldera volcanism are small dacite domes extruded from the ring-fracture system into a deep caldera lake and a dacite pumice fall dated at ca. 2,300 14C yr B.P. The lake probably filled to its maximum of ~620 m above sea level (asl) within a few hundred years of caldera collapse. Pumice Dome (~67.5 weight percent SiO2) is compositionally similar to lava of the northwest flank flow and to lava exposed in the west wall of the 1931 Main Crater within the caldera, suggesting lateral transport of magma from a common source. Similarly, Vulcan and West Domes (~65.7 weight percent SiO2) are geochemically indistinguishable yet were emplaced on opposite sides of the caldera floor. Adjacent to Vulcan, Bolshoi Dome is the least evolved (64.2 weight percent SiO2). These postcaldera dacite-rhyodacites are not remnants of Aniakchak II magma but resulted from differentiation of recharge andesite or basaltic andesite magma.\"","StartYear":-350,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":80,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":3971,"Name":"Aniakchak Vent Mountain Lava Flows","Description":"From Bacon and others (2014): \"We describe the eruptive history of Vent Mountain beginning with lava flows inferred to be some of the earliest. Thickly tephra-mantled lava that flowed between Bolshoi Dome and Surprise Cone and now fronts onto Surprise Lake apparently came from Vent Mountain, as did lava that flowed between Surprise and Windy Cones. Early lava flows that originated at the west-northwest-east-southeast-trending fissure that cuts the south flank of Vent Mountain and from the summit crater are exposed in the walls of the fissure, as scattered outcrops on the south flank, overlying the east edge of New Cone, and in the walls of the two maar craters. The most far travelled of these flows terminates ~1 km southwest of The Gates (fig. 10A [in original text]).","StartYear":-350,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":80,"StartQualifierUnit":"Years","EndYear":1110,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":30,"EndQualifierUnit":"Years","Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":1921,"Name":"Augustine Southeast Point Debris Avalanche","Description":"From Waitt and Beget (1996): \"Between about 2100 and 1800 yr B .P. (between tephra layers G and D) two large debris avalanches swept east and southeast to the sea.\"\r\n\"Overlying the Yellow Cliffs diamict and beneath tephra layer I along the coastal cliff 350 m west of Southeast Point lies a diamict at least 8 m thick with in situ boulders as large as 3.5 m, and winnowed ones cm the beach below as large as 7 .5 m. The angular clasts are gray to reddish and scarcely altered, contrasting the underlying Yellow Cliffs diamict. The deposit extends at least 2.5 km northeast along the coastal cliffs to East Point, where it is also overlain by the I tephra and that, in turn, overlain by the Northeast Point debris-avalanche deposit. The surface slope at top of sea cliff, if projected seaward indicates that deposit has been wave eroded back at least 0.5 km. perhaps 1.5 km.\"\r\n\"During this prehistoric period numerous domes must have been emplaced at the summit, repeatedly renewing the source for catastrophic debris avalanches. Remnants of these older domes form the east and south sides of the present summit-dome complex. Below the summit area at least three domes were emplaced on the upper flanks, one on the south (Karnishak dome), two on the northwest (domes \"I\" and \"H\"). Another undated and nearly buried dome or lava flow diversifies the upper south flank.\"","StartYear":-210,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":60,"StartQualifierUnit":"Years","EndYear":120,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":80,"EndQualifierUnit":"Years","Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":1941,"Name":"Augustine Yellow Cliffs Debris Avalanche","Description":"From Waitt and Beget (1996): \"Between about 2100 and 1800 yr B .P. (between tepbra layers G and D) two large debris avalanches swept east and southeast to the sea.\"\r\n\"Overlying the G tephra (sparsely exposed) that caps the East Point debris-avalanche deposit is a highly oxidized massive diamict containing angular altered andesite boulders commonly 1-2 m in diameter, some as large as 3.5 m. This distinctively yellowish unit 5 to 9 m thick forms the middle to upper part of the sea cliff for at least 25 km along the east coast. The matrix and large clasts alike are strongly altered to soft zeolite (?) and clay, but the unit also contains sporadic pods meters in diameter of gray to reddish coarse diamict of scarcely altered andesite. Midway between East Point and Northeast Point its surface shows sharp local relief of 3-4 m where directly buried by the Northeast Point debris-avalanche deposit. At the south of Southeast Point the Yellow Cliffs diamict is overlain by the gray Southeast Point debris-avalanche deposit, which is capped by the I tephra.\"\r\n\"The hummocky surface topography and the massive and coarse texture clearly identify the Yellow Cliffs diamict as a debris-avalanche deposit. The enclosed pods of unoxidized diamict and the fact that the unit is both overlain and underlain by unoxidized to weakly oxidized similar diamicts shows that the heavy alteration had occurred before the avalanche.\"\r\n\"During this prehistoric period numerous domes must have been emplaced at the summit, repeatedly renewing the source for catastrophic debris avalanches. Remnants of these older domes form the east and south sides of the present summit-dome complex. Below the summit area at least three domes were emplaced on the upper flanks, one on the south (Karnishak dome), two on the northwest (domes \"I\" and \"H\"). Another undated and nearly buried dome or lava flow diversifies the upper south flank.\"","StartYear":-210,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":60,"StartQualifierUnit":"Years","EndYear":120,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":80,"EndQualifierUnit":"Years","Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":1911,"Name":"Augustine Tephra G","Description":"From Waitt and Beget (1996): \"...a tephra layer \"G\" dated at about 2200-2000 yr B.P. ...\"\r\nFrom Waitt and Beget (2009): \"The lowest five coarse-pumice beds at the coast-tephras G, I, H, C, and O-drifted east and southeast. Tephra G and ambiguous tephra O are known only from a few sites each on the east and southeast, neither with enough data points to warrant a map.\"\r\nFrom Tappen and others (2009): \"Tephra G is an oxidized yellow to tan fall deposit that has tephra clasts ≤10 cm in diameter at its base; this unit fines upward (Waitt and Beget, in press).\"","StartYear":-150,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":3691,"Name":"Okmok CFE II","Description":"From Miller and Smith (1987): \"The Okmok volcanic center, Umnak Island (Fig. 1 [in original text)], is a large basaltic composite volcano with a caldera system marking the summit area. This system consists of two large partially overlapping calderas (Byers, 1959), each with an estimated diameter of about 10 km. Postglacial ash-flow tuffs exposed in sea-cliff exposures on the northwest side of the volcano are locally separated by a lava flow 6-9 m thick (Miller and Smith, 1975). A hiatus between extrusion of the lava and deposition of the upper ash-flow sheet is indicated by a well-developed erosional surface on the lava flow; in places, stream channels were cut through the lava flow and later filled by the younger ash flow. The occurrence of two major ash-flow units strongly supports the probability of two major caldera-forming eruptions in Holocene time.\"\r\n\"Charcoal directly beneath the upper ash-flow tuff unit on the north side of the island yielded a 14C age of 2400±+/-200 yr (sample 1, Table 1 [in original text]). This is a maximum age for the second ash-flow tuff eruption, presumably the second caldera forming eruption (Table 2 [in original text]). A minimum of about 5500 yr separates the two caldera-forming eruptions, assuming the correlations are correct.\"\r\nFrom Beget and others (2005): \"The second large caldera-forming eruption produced a pyroclastic flow deposit that buried the older pyroclastic flow and almost all other older volcanic and non-volcanic sediments on all flanks of Okmok Volcano. The deposits of this caldera-forming eruption are as much as 80 meters thick near the caldera rim, and 30 to 40 meters thick at some coastal exposures (fig. 7 [in original text]). The most distal deposits preserved on land are found 25 kilometers to the southeast across Umnak Pass on southern Unalaska Island. Sea cliff exposures on the north, east, and south flanks of the volcano show where the pyroclastic flow advanced into the sea in these directions. New radiocarbon dating on plants found buried and incinerated at the base of the pyroclastic flow indicates the second caldera-forming eruption occurred about 2,050+/-50 14C years ago (Begét and Larsen, 2001). This eruption generated a tsunami which affected the westernmost part of Unalaska Island.\"\r\nFrom Larsen and others (2007): \"...the Okmok II deposits are usually significantly thinner than Okmok I, which leads to significantly lower eruptive volume estimates. Burgisser (2005) notes the total volume of the initial rhyodacite and andesite Plinian fall deposits are ~0.5 km3, whereas the main pyroclastic flow deposits are estimated to be ~15 km 3 on-island.\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2017) reports a magnitude of 6.7, bulk eruptive volume of 50 cubic km and a dense rock equivalent eruptive volume of 29 cubic km for the eruption.","StartYear":-100,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":50,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Okmok","ParentVolcano":"Okmok","VolcanoID":"ak206","ParentVolcanoID":"ak206"},{"ID":3721,"Name":"Okmok 2000 yBP","Description":"From Beget and others (2005): \"A debris avalanche deposit up to 10 meters thick overlies the 2,000-year-old pyroclastic flow surface on the southeast flank of Okmok Volcano. This debris avalanche originated on Tulik Volcano, covers 20 square kilometers, and the resulting deposit can be traced more than 6 kilometers down slope to the shore of the Pacific Ocean.\"","StartYear":-50,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Okmok","ParentVolcano":"Okmok","VolcanoID":"ak206","ParentVolcanoID":"ak206"},{"ID":3711,"Name":"Okmok 2000 yBP","Description":"From Beget and others (2005): \"One of the most detailed records of explosive volcanism occurs at Kettle Cape, where 24 tephra layers were deposited since the 2,000-year-old pyroclastic flow (fig. 6 [in original text]). This record suggests that explosive eruptions large enough to put acentimeter or more of ash in coastal areas around Okmok Volcano since the second caldera-forming eruption have occurred approximately every 75 years over the last two millennia. This frequency is about twice as high as the recurrence interval estimated for explosive eruptions for the six millennia prior to the 2,000-year-old caldera-forming eruptions, suggesting that a possible increase in eruption frequency and/or explosivity began after the second caldera-forming eruption.\"","StartYear":-50,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Okmok","ParentVolcano":"Okmok","VolcanoID":"ak206","ParentVolcanoID":"ak206"},{"ID":1541,"Name":"Mt Churchill White River North Lobe","Description":"From Preece and others (2014): \"The White River Ash (WRA) is an important Holocene chronostratigraphic marker through-out eastern Alaska (USA) and in Yukon and western Northwest Territories (Canada) (Lerbekmo and Campbell, 1969; Pewe, 1975), and provides age control for peat studies (Harris and Schmidt, 1994; Robinson and Moore, 1999, 2000), glacial fluctuations (Denton and Karlen, 1977), paleoecological studies (Slater, 1985), and archaeological and anthropological studies (Workman, 1979; Moodie and others, 1992) (Fig. 1 [in original text]). WRA has been defined by its geographic distribution and its stratigraphic position, combined with radiocarbon dating, with less emphasis on its petrographic and geochemical features. The northern lobe erupted between A.D. 150 and 500 (Jensen and Froese, 2006) or ca. 1900 yr B.P. (Lerbekmo and others, 1975), while the eastern lobe erupted A.D. 803 or 1147 cal. yr B.P. (Clague and others, 1995).\"\r\n\"The exact vent area of the WRA has been disputed, and two possible locations have been suggested. Lerbekmo and Campbell (1969) postulated that the WRA vent was located on the floor of a deep valley beneath the Klutlan Glacier near what they identified as a large pumice mound (4 in Fig. 2 [of original text]). McGimsey and others (1992) and Richter and others (1995) questioned the likelihood of a vent located at the floor of a valley lacking an edifice or nearby volcano, and proposed that Mount Churchill was the vent. Lerbekmo (2008) questioned whether Mount Churchill was a volcano, and reiterated that the vent for WRA was underneath the Klutlan Glacier.\"\r\n\"The WRA consists of a single light colored tephra layer in most distal exposures, but in a few places both the northern and eastern lobes are preserved in stratigraphic succession.\"\r\nFrom Richter and others (1995): \"The White River Ash is a bilobate Plinian fallout deposit covering more than 340,000 km square and containing an estimated 25-50 km cubed of tephra (bulk volume) (Bostock 1952; Berger 1960) (Fig. 1 [in original text]).\"\r\nFrom Lerbekmo and others (1975): \"A northern lobe and an eastern lobe have axis lengths in excess of 500 and 1000 km respectively.\"\r\nFrom Preece and others (2014): \"Unfortunately, glass compositions are similar in the northern and eastern lobes of the WRA tephra, and published analyses cover a significant range, making it difficult to assign a particular tephra sample to a specific lobe (Addison and others, 2010; Payne and others, 2008; Lakeman and others, 2008; Froese and Jensen, 2005; Richter and others, 1995; Beget and others, 1992; Downes, 1985).\"\r\n\"Tephra samples of the WRA contain phenocrysts of plagioclase, amphibole, magnetite, ilmenite, and trace amounts of orthopyroxene and apatite within highly vesicular, frothy color-less glass (Table S8 in the Supplemental File [see footnote 1] [of original text])...Biotite was not found in any of the northern lobe samples, although two samples contained trace amounts of reddish-brown phenocrysts tentatively identified as oxyhornblende (Table S8 in the Supplemental File [see footnote 1] [of original text]).\"\r\n\"Previous studies have demonstrated that the eastern and northern lobes of the WRA have different ilmenite compositional ranges (Lerbekmo and others, 1975; Downes, 1985; Richter and others, 1995) and this distinction has been used to define geochemical groups WRA-E and WRA-N.\"\r\n\"WRA deposits can be assigned to WRA-E or WRA-N, and are best identified using ilmenite compositions. Within WRA-N there are two distinctive compositions, WRA-Na and WRA-Nb. In the proximal area, ca. 1900 yr B.P. (Lerbekmo and others, 1975) WRA-Na displays increasing silica content accompanied by systematic changes in trace element compositions, Fe-Ti oxide compositions, and temperature-fugacity estimates. WRA-Nb may represent either a restricted phase of the WRA-Na or a separate eruption from the Mount Churchill magmatic system.\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2017) reports a magnitude of 6.2 bulk eruptive volume of 25 cubic km and a dense rock equivalent eruptive volume of 10.42 cubic km for the eruption.","StartYear":50,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Churchill, Mt","ParentVolcano":"Churchill, Mt","VolcanoID":"ak50","ParentVolcanoID":"ak50"},{"ID":2721,"Name":"Kanaga T8/Yellow-Brown-Olive Ash","Description":"From Waythomas and others (2001): \"Groups of tephra deposits so defined indicate that at least 11 eruptions of Kanaga Volcano have occurred since about 11 ka. Most of these eruptions were probably sub-Plinian to Plinian, producing moderately vesicular dacitic pumice lapilli tephra deposits ranging in thickness from a few centimeters to more than 1 m (table 2 [in original text]).\"\r\n\"Pumice-lapilli fall and flow deposit.\"\r\nWaythomas and others (2001) correlate T8 on Kanaga with the Yellow-Brown-Olive Ash of Black (1980) on Adak Island, based on age equivalency.","StartYear":77,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":380,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kanaga","ParentVolcano":"Kanaga","VolcanoID":"ak144","ParentVolcanoID":"ak144"},{"ID":1231,"Name":"Aniakchak Caldera Lake Drain","Description":"From Bacon and others (2014): \"Surprise Lake (1,055 ft, 322 m asl) is a remnant of a larger caldera lake evidenced by wave-cut benches on the northeast caldera walls and patches of lake sediment at several locations within the caldera (McGimsey and others, 1994). The lake filled until it overtopped a low point on the east rim of the caldera and then rapidly drained, possibly aided by eruptive activity (McGimsey and others, 1994) or by headward erosion of the canyon of the Aniakchak River. The draining produced a catastrophic flood as the ensuing torrent cut the gorge called The Gates in altered and fractured sedimentary rock (Waythomas and others, 1996). At the time of these publications, the ~1,610 ft (490 m) asl wave-cut terrace recognized by McGimsey and others (1994) was thought to represent the high stand of the caldera lake. Subsequent fieldwork indicated that all four dacite domes were emplaced subaqueously. Because West Dome has a summit elevation of 2,002 ft (610 m), the lake must have reached at least that height, although uplift or tilting of the southwestern caldera floor since the lake drained cannot be ruled out. McGimsey and others (1994) noted that Birthday Pass, elevation ~2,030 ft (620 m), evidently was not overtopped by the lake. Two additional low points in the caldera rim, northeast and east of Surprise Lake, are at ~2,130 ft (650 m) elevation. Both are underlain by Aniakchak volcanic rocks. Before downcutting, the minimum elevation of the caldera wall at The Gates implied by the topographic map (U.S. Geological Survey, 1963; fig. 10B [in original text]) could have been between ~1,900 ft (580 m) and ~2,100 ft (640 m). Because West Dome was emplaced beneath water, its summit elevation and the elevations of Birthday Pass and other low points on the caldera rim together suggest that the surface of the caldera lake probably reached close to 2,030 ft (620 m) asl before it overtopped the wall and cut The Gates. When the lake drained is constrained by radiocarbon ages of 1,850+/-40 yr B.P. on soil (silt) and 1,870+/-30 yr B.P. on wood from above pebbly sediment near the Aniakchak River mouth (VanderHoek and Myron, 2004, their table 8.1, appendix C, and p. 161-162). The weighted mean of these ages is 1,860+/-30 yr B.P. (table 1 [in original text]), which apparently dates a change from a pebbly beach to a depositional environment. The suggested date for the flood falls within an ~200 yr gap in human habitation near the mouth of the Aniakchak River (VanderHoek and Myron, 2004, p. 190-191). Evidence for lake sediments on apparently younger tuff cones within the caldera presented in the next section suggests that the catastrophic draining that produced the flood did not cut The Gates to their entire depth but left a residual lake that was larger and higher than present Surprise Lake.\"","StartYear":90,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":30,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":2451,"Name":"Hayes Devil Tephra","Description":"From Riehle (1985): \"...only 1 [tephra] younger than the 3650 yr [Hayes tephra set H], have been recognized.\"\r\n\"Another comparatively minor eruption between 500 and 1000 yr ago is also assigned to Hayes volcano.\"\r\nFrom Waythomas and Miller (2002): \"A single bed of volcanic ash (fig. 6 [in original text]), geochemically similar to the other known Hayes ashes, was erupted about 500 years ago (Riehle, 1985). Although the aerial extent of this ash deposit is not well known, the ash bed probably records a minor eruption of the volcano about 500 years ago.\"\r\nFrom Dixon and Smith (1990): \"The unit is a pale brown (10YR 6/3 to pinkish white (7.5YR 8/2) volcanic ash. It is typically 3 to 5 cm thick, but commonly occurs up to 8 cm thick. Mineralogically it is indistinguishable from the Watana tephra (s).\"\r\nFrom Mulliken (2016): \"High geochemical similarity and the generally homogenous glass composition among samples of the Devil tephra within the mSRV [middle Susitna River Valley, Alaska] suggest that it represents a single eruptive event. High similarity between the Devil tephra and proximal Hayes Volcano reference tephra suggest that the Devil tephra is a product of Hayes Volcano and perhaps even the Hayes tephra set H. Riehle (1985) reports on a Hayes Volcano sourced tephra layer dating younger than 1605-1990 cal yrs B.P. at sampling site 27, which coincides with the range of dates that bound the Devil tephra in the mSRV [middle Susitna River Valley, Alaska] (Figure 6.1 [in original text]). Riehle (1985), however, does not provide a physical or chemical description of this young tephra, making a correlation only tentative. Future tephra sampling near Hayes Volcano may clarify the origin and distribution of the Devil tephra as well as improve the current knowledge of the timing of hazards posed by Hayes Volcano.\"","StartYear":110,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":20,"StartQualifierUnit":"Years","EndYear":160,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":20,"EndQualifierUnit":"Years","Volcano":"Hayes","ParentVolcano":"Hayes","VolcanoID":"ak116","ParentVolcanoID":"ak116"},{"ID":1961,"Name":"Augustine Northeast Bench Debris Avalanche or Lahar","Description":"From Waitt and Beget (1996): \"A bouldery gravel diamict (unit JH) containing angular porphyritic andesite stones as large as 4 m lies outside (north of) the levee that delineates the north side of main body of Northeast Point debris-avalancbe deposit (unit IHa). The seaward part of this unit north of the levee is relatively nonhummocky and called here Northeast Bench. By this morphology the unit underlying the bench is interpreted as a lahar deposit (unit IHl). But more than 200 m back from the sea cliff the area outside levee is nearly as hummicky as that south of the levee and this is also mapped with unit IHa. Both map units (units IHl and IHa) are overlain by a tephra sequence with tephra H at its base. The flattish seaward-sloping part of this area delineating the bench may be a laharic phase that issued from the debris avalanche.\"\r\n\"Sandy gravel lacking large blocks underlies H? tephra atop the Pleistocene landslide block *Unit Pl) on south side of island. It may contemporaneous with Northeast Bench lahar (?) deposit.\"","StartYear":225,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":25,"StartQualifierUnit":"Years","EndYear":480,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":160,"EndQualifierUnit":"Years","Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":1971,"Name":"Augustine Northeast Point Debris Avalanche","Description":"From Waitt and Beget (1996): \"Between 1700 and 1400 yr B.P. (between tephras I and H) a large debris avalanche shed east and east-northeast to the sea.\"\r\n\"Underlying the H tephra, a coarse and massive diamict extends coastwise for more than 4 km from north of Northeast Point to south of East Point. The deposit contains angular boulders of gray andesite as large as 7 m in intermediate diameter. The surface is broadly hummocky, having a relief of 3 m over distances of 50 m. At East Point is at least 20 m thick (base nor exposed); it tapers south 1.5 km south of East Point to 7 m thick, from where it pinches out within a few hundred meters. Its south part overlies three older debris-avalanche deposits (see above). The north side of the main body of deposit is delineated by a straight levee 3-8 m high. But similarly hummocky, bouldery deposit also lies north of (outside) this levee. This northern bouldery debris may also be part of the Northeast Point debris avalanche, but of a phase that immediately preceded the levee-forming phase. This coarse rubbly diamict is exposed in the walls of incised gullies upslope, apparently tracable up to the base of the summit dome complex. Mantling tephra (lowest coarse tephra = H) and humus three meters and more thick have considerably smoothed this topography. But beneath this mantle in coastal exposure it has a sharp local relief of at least 6 m over distances of 20m. A few boulders larger than 2.5 m in the top of the deposit protrude through the thick tephra-humus blanket.\"\r\n\"About 0.8 km south of Northeast Point the upper part of the deposit is strikingly monolithologic, every fragment angular, only a low proportion finer than pebble size. Here the deposit appears to be a single dome block at least 30 m long; it is more disaggregated than so-called \"jig-saw\" blocks in the 1980 Mount St. Helens avalanche described by Glicken (1986), yet it did not dilate and disaggregate enough to form or admit matrix. This huge block must have piggybacked more or less intact atop the moving avalanche, for such a gigantic block cannot have been moved by pyroclastic flow or lahar. Detterman (1973) mistook this bouldery fragmental deposit, like the others along this coast, for in-situ lava flow.\"\r\n\"At Northeast Point the deposit crosses a straight east-facing scarp 650 m long and 30 m high that lies about 450 m back from the sea at Northeast Point. This sea cliff had been cm into tile Yellow Cliffs (and older?) debris-avalanche deposits. The capping section including a lowermost coast pumice (layer H) is the same before the scarp as it is behind. Thus the scarp was overridden and buried by the Northeast Point debris avalanche albeit not thickly enough to obliterate it utterly (fig. 6B [in original text]). The debris avalanche deposit is at least 20 m thick (base not exposed) seaward of the buried sea cliff whose original height therefore must have been at least 40 m.\"\r\n\"Nearly continuous boulders, some as large as 5 m, extend at least as far as 600 m offshore of Northeast Point, showing that the original deposit has been eroded back at least that far into its present sea cliff.\"\r\n\"During this prehistoric period numerous domes must have been emplaced at the summit, repeatedly renewing the source for catastrophic debris avalanches. Remnants of these older domes form the east and south sides of the present summit-dome complex. Below the summit area at least three domes were emplaced on the upper flanks, one on the south (Karnishak dome), two on the northwest (domes \"I\" and \"H\"). Another undated and nearly buried dome or lava flow diversifies the upper south flank.\"","StartYear":225,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":25,"StartQualifierUnit":"Years","EndYear":480,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":160,"EndQualifierUnit":"Years","Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":3051,"Name":"Seguam 1700 yBP","Description":"From Jicha and Singer (2006): \"The 1710 dome (str), the westernmost outcrop of postcollapse rhyolites, abuts the southern margin of the crater rim. Glass + magnetite + orthopyroxene + whole rock from this dome gave a U-Th mineral isochron age of 1.7+/-0.5 ka (Jicha and others, 2005).\"","StartYear":250,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":500,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Seguam","ParentVolcano":"Seguam","VolcanoID":"ak246","ParentVolcanoID":"ak246"},{"ID":1951,"Name":"Augustine Tephra I","Description":"From Waitt and Beget (2009): \"The lowest five coarse-pumice beds at the coast-tephras G, I, H, C, and O-drifted east and southeast. Tephra G and ambiguous tephra O are known only from a few sites each on the east and southeast, neither with enough data points to warrant a map. Drawn from data at many stratigraphic exposures, isopach maps clearly show tephras I, H, and C drifted east-southeast and southeast.\"\r\n\"Several decimeters of thin beds of fine sand to silt (ash) separate tephra layers I and H (fig. 6 [in original text]).\"\r\n\"The two major Augustine proximal tephras that are also identified in distal locations are tephra B (about 390 yr B.P.) and tephra I (about 1,700 yr B.P.). Tephra I is about 3 cm thick at a distance of 110 km, and B is about 7 mm thick at a distance of 200 km (fig. 8 [in original text]).\"\r\nFrom Tappen and others (2009): \"Tephra I is a gray pumiceous fall layer that is 2-4 cm thick and appears to be reworked as it also contains soil...\"","StartYear":250,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":2861,"Name":"Lost Jim Cone 1655 yBP","Description":"From Wood and Kienle (1990): \"The Lost Jim Flow erupted 1,655 yr BP...\"\r\nFrom Hopkins (1963): \"The name Lost Jim lava flow is proposed for the youngest lava flow in the Imuruk Lake area-a large pahoehoe lava flow, virtually undisturbed by frost riving, that extends from its source at Lost Jim Cone northward to the shore of Imuruk Lake, westward to the shore of Lava Lake, and southwestward to the Kuzitrin River (pl. 1, fig. 15 [in original text]).\"","StartYear":295,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":220,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Lost Jim Cone","ParentVolcano":"Imuruk Lake Volc Field","VolcanoID":"ak185","ParentVolcanoID":"ak125"},{"ID":1891,"Name":"Augustine Homer Ash","Description":"From Waitt and Beget (2009): \"A probably Augustinian ash dated to about 2,275 yr B.P. lies near Homer 110km northeast of Augustine.\"","StartYear":325,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":25,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":1421,"Name":"Akutan CFE/Akutan Tephra","Description":"From Miller and Smith (1987): \"A 2-km-diameter summit caldera on neighboring Akutan Island (Fig. 1 [in original text]) has been the source for small-volume pyroclastic flows of andesitic composition on the north side of the volcano. Reeder (1983), on the basis of 3 dates, reported a 1C age of 5200+/-200 yr on organic material directly beneath the pyroclastic-flow deposit. This is a maximum date for the climactic eruption which, like that of Makushin, is thought to be relatively small.\"\r\nFrom Waythomas and others (1998): \"A widespread, 1-to-2-meter-thick, coarse-grained volcanic ash deposit (tephra) and associated pyroclastic-flow and lahar deposits in Long Valley and Broad Bight (fig. 3 [in original text]) are correlated with the eruption that formed the present caldera about 1600 years ago. This eruption spread black, scoria-rich, lapilli tephra overmost of Akutan Island, especially east of the volcano. Volcanic bombs, 7 to 10 centimeters in diameter, were found in the Akutan Harbor area and were probably ejected from the vent during the caldera-forming eruption. The caldera-forming eruption is the largest known eruption of Akutan Volcano in the past 8000 years.\"\r\nFrom Richter and others (1998): \"Evidence from tephra and lahar stratigraphy and from tephra, bomb, and lava composition suggests that the modern caldera formed about 1611 year B.P. during a major Strombolian and sub-Plinian eruption.\"\r\nFrom Waythomas (1999): \"The previously unrecognized and widespread Akutan tephra and the pyroclastic-flow and lahar deposits in Long valley, Flat Bight valley, and Broad Bight valley that conformably overlie the tephra are correlated with a major eruption of Akutan Volcano approximately 1611 years B.P. The age of this eruption is based on radiocarbon-dated soils just beneath the Akutan tephra (Table 1 [in original text]). The Akutan tephra is the thickest, most extensive, and physically prominent of all known tephra deposits on Akutan Island. The direct stratigraphic association of the tephra with noncohesive lahar and pyroclastic- flow deposits in multiple valleys on the volcano is evidence for a relatively large plinian(?) eruption. With the exception of the deposits exposed at Reef Bight (sections 61 and 76, Fig. 8 [in original text]), the volcaniclastic deposits associated with the Akutan tephra are the only known deposits that record a significant eruption of Akutan Volcano. A possible explanation for the origin of the tephra and associated volcaniclastic deposits is that they formed during the eruption that produced the present summit caldera. If this explanation is correct, the most recent caldera-forming eruption of Akutan Volcano occurred approximately 1611 years B.P. This new age estimate for the formation of Akutan caldera would revise a previous date on caldera formation of 5200 years B.P. (Reeder 1983; Miller and Smith 1987). According to the results presented in this paper, few if any deposits on Akutan Island can be correlated with confidence to an eruption that dates to approximately 5200 years B.P. (Fig. 19 [in original text]). Noncohesive lahar deposits in Flat Bight are younger than approximately 6000 years B.P., but older than the Akutan tephra. A single noncohesive lahar deposit at Reef Bight (Fig. 19 [in original text]) is younger than approximately 8500 years B.P. These lahar deposits are not associated with tephra or other volcaniclastic deposits, as would be expected if they were part of an eruption sequence associated with caldera formation. Thus, it seems logical that the thick, aerially extensive sequences of Akutan tephra, lahar, and pyroclastic-flow deposits most likely record the most recent caldera-forming eruption at Akutan Volcano.\"\r\nFrom Waythomas (1999): \"A black, scoria-bearing, lapilli tephra, informally named the \"Akutan tephra,\" is up to 2 m thick and is found over most of the island, primarily east of the volcano summit. Six radiocarbon ages on the humic fraction of soil A-horizons beneath the tephra indicate that the Akutan tephra was erupted approximately 1611 years B.P. At several locations the Akutan tephra is within a conformable stratigraphic sequence of pyroclastic-flow and lahar deposits that are all part of the same eruptive sequence. The thickness, widespread distribution. And conformable stratigraphic association with overlying pyroclastic-flow and lahar deposits indicate that the Akutan tephra likely records a major eruption of Akutan Volcano that may have formed the present summit caldera.\"\r\n\"A black-to-orange-brown, scoria-rich, lapilli tephra that is as much as 2-m-thick is found in at least 12 stratigraphic sections in a 180 degree sector southeast of the caldera (Fig. 3 [in original text]). This tephra (hereafter called the Akutan tephra) is present in Long valley, Flat Bight valley, Broad Bight valley, along the coast in Hot Springs Bay, and in various exposures around Akutan Harbor (Fig. 3 [in original text]). The Akutan tephra is the thickest tephra recognized on Akutan Island. In general, it consists of three components (in stratigraphic order): a 0.5- to 1-m-thick, black, scoria-rich zone, with crude inverse grading and large bombs (both lithic and juvenile); an orange-brown lithic-rich lapilli zone, 0.2-0.5 m thick; and a 0.2- to 0.5- 143 m-thick, gray-brown silty ash which is 80-90% accretionary lapilli (Fig. 4 [in original text]). In a few sections a 0.2- to 0.4- m-thick bed of orange-brown, lithic-rich lapilli tephra makes up a fourth component. Juvenile clasts in the tephra are mostly scoriaceous, porphyritic, two-pyroxene andesite. The three-component sequence is similar in all locations where the tephra is ~ l m thick. Volcanic bombs in the scoria-bearing zone of the tephra are up to 20 cm in diameter (maximum clast dimension) and generally decrease in size with increasing distance from the caldera (Fig. 3 [in original text]).\"\r\n\"The tephra rests on a thin A/Cox soil at six of the 12 known outcrops. Radiocarbon dates on the humic fraction of soil A-horizons (Cherkinsky and Brovkin 1993) from these six sites (Table 1 [in original text]) indicate that the Akutan tephra was deposited approximately 1723+/-36 radiocarbon years B.P., which is a mean weighted age of six ages. Using the calibration routine of Stuiver and Reimer (1993), the calibrated age of this date is 1611 years B.P. or A.D. 339.\"\r\n\"The thickness of the Akutan tephra exhibits a distinct decrease with increasing distance away from the caldera (Fig. 3 [in original text]). In Long valley and in Broad Bight valley, the Akutan tephra is directly overlain by lahar and pyroclastic-flow deposits that contain clasts of juvenile scoriaceous andesite similar to the scoriaceous bombs in the tephra. Contact relations between the tephra and the overlying lahar and pyroclastic-flow deposits are gradational, indicating a continuous depositional sequence. Where the Akutan tephra is overlain by lahar and pyroclastic-flow deposits, it is unweathered and exhibits no soil development, indicating that it was not exposed subaerially. The widespread distribution of the Akutan tephra and its conformable stratigraphic relation with overlying lahar and pyroclastic-flow deposits are evidence for a major eruption that could have been the most recent caldera-forming eruption of the volcano. The tephra is mineralogically similar to historical Akutan tephras and is a good stratigraphic marker on Akutan Island, but it has not yet been identified on nearby Unalaska. Akun or Unimak Islands.\"\r\n\"Lahar and pyroclastic-flow deposits in Long valley overlie, and are younger than, the Akutan tephra (Fig. 6 [in original text]). The direct stratigraphic association of the tephra with lahar deposits at sections 78 and 85 (Fig. 6 [in original text]) indicates a genetic relationship among the deposits that records a major eruption, possibly the most recent caldera-forming eruption of Akutan Volcano.\"\r\n\"At least two thick, compact, indurated, noncohesive lahars are present in the upper part of Broad Bight valley (section 50, Fig. 12 [in original text]). These deposits are more than 50 m thick and extend downstream for several kilometers. The lahar deposits contain angular to subangular lithic clasts of andesite and basaltic andesite and are matrix supported and massive. The age of these deposits is unknown, but they record a significant eruption that may have been the most recent caldera-forming eruption at Akutan Volcano. Lahar deposits exposed downstream of section 50 at section 42 (Fig. 12 [in original text]) are thinner, finer grained, and better sorted than those in the upper part of the valley, a contrast that indicates downstream flow transformation.\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2016) reports a magnitude of 5.0, bulk eruptive volume of 1 cubic km and a dense rock equivalent eruptive volume of 0.4 cubic km for the eruption.","StartYear":339,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":1821,"Name":"Akutan Broad Bight Valley Lahars","Description":"From Waythomas (1999): \"Broad Bight valley is a wide glacial valley on the south side of Akutan Island, southeast of the caldera (Fig. 1 [in original text]).\"\r\n\"Lahar deposits in the middle part of Broad Bight valley (sections 58, 70, 71, Fig. 12 [in original text]) form a downstream thinning fan that covers the valley floor to a depth of at least 2 m. These lahar-runout deposits are distinctly finer grained (largest clasts are pebble size) and contain a greater percentage of fines (silt+clay) than their upstream counterparts. At section 87 (Fig. 12 [in original text]) lahar runout deposits overlie the Akutan tephra. Indicating that most, if not all, of the lahar deposits in Broad Bight valley are younger than the tephra.\"","StartYear":339,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":1831,"Name":"Akutan Flat Bight Valley Lahars","Description":"From Waythomas (1999): \"Downstream from section 81 at section 97 (Fig. 1 [in original text]), at least two lahar deposits are present but no tephra deposits are preserved (Fig. 9 [in original text]). The lahar deposits are younger than the Akutan tephra but are otherwise undated.\"","StartYear":339,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":2391,"Name":"Fisher Maar/Flood","Description":"From Stelling and others (2014): \"The caldera was, at one point, completely filled with water to a maximum depth of ~100 meters, as evidenced by beach deposits high on the inside of the caldera rim (fig. 8 in original text). An explosive phreatomagmatic eruption occurred from within the collapsed Turquoise cone area about 1,500 years ago and likely generated a tsunami in the caldera lake that spread radially (Stelling and others, 2005). Tsunami wave deposits from the collapse of Turquoise cone and subsequent phreatomagmatic eruptions are present at the north shore of the modern western caldera lake and on the isthmus between the northern lakes, along with erosional scars from the waves. The most dramatic effect waves had on the caldera was on the southern wall, where a wave overtopped the caldera rim. Cobbles from a wave-cut terrace on the southern wall have been lifted ~20 meters higher onto the top of the caldera wall. The resistant, caldera-forming eruption deposit that caps the southern caldera wall was incised, and the wave at least partly eroded the softer underlying deposits in the wall to form a canyon below lake level. The combined erosion of the tsunami and the newly-draining lake carved the modern 100-meter-deep southern outflow canyon (figs. 6D and 8 [in original text]), allowing the lake to drain catastrophically. Had the lake drained gradually through incremental erosion of the southern outflow canyon, beach deposits reflecting periods of lower lake levels would be present along the inner caldera wall. The absence of these deposits, as well as the presence of large boulders (up to 5 meters in diameter) of dense pyroclastic flow material torn from the top of the caldera wall and found more than 2 kilometers downstream in the southern outflow canyon, support a catastrophic flood event. During the lake-draining event, Turquoise cone and Mt. Finch acted as earthen dams, preserving the lakes in the northern portion of the caldera.\"\r\nFrom Stelling and others (2005): \"The collapse of Turquoise Cone was not the last activity in this region of the caldera. Thick surge deposits exposed on the eastern shore of Turquoise Lake were emplaced after collapse, and have been dated at 1500 years (Table 3 [in original text]). Several young cinder cones have developed adjacent to the remnant arcuate ridge of Turquoise Cone. Currently, hydrothermal plumes within the Turquoise Lake are stirring sediment, providing the notable water color. The intensity and distribution of this hydrothermal system is variable, as plumes in the western caldera lake appear and disappear within 1 year.\"\r\n\"After the collapse of Turquoise Cone, only a small arcuate ridge remained above the caldera lake surface. A relatively recent explosive eruption from this vent created a small mound of red-orange scoria that extended the southern limb of the Turquoise Cone amphitheater. Hydrothermally altered lithics associated with this event are found strewn across the caldera, suggesting a phreatic component to the eruption. Soils immediately below this deposit have been dated at 1500 (+/-50) years. We suggest this eruption generated a wave in the caldera lake that spread radially. Wash deposits from this wave are found at the north shore of the modern west lake and on the base of the small cinder cone (IC in Fig. 3C [in original text]) between the northern lakes, along with erosional scars from the wave itself. The most dramatic evidence for this wave appears on the southern caldera wall. Cobbles from the wave-cut terrace on the southern wall are found ~20 m higher, where they overtop the lowest part of the caldera rim. The densely welded pyroclastic flow from the caldera-forming eruption that caps the southern caldera wall has been deeply incised at this location. Within the southern canyon, large boulders (up to 5 m in diameter) of welded tuff are found several kilometers downstream from the nearest densely welded exposure of the flow, indicative of a flood deposit. Similar features have been found in the outflow canyons of Medicine Lake volcano in California (Donnelly-Nolan and Nolan, 1986) and Aniakchak Volcano in Alaska (Waythomas and others, 1996). Organic-rich soil directly above this flood deposit has a 14C date of 1500 (+/-50) years, matching the date of the Turquoise Cone explosive eruption. The presence of flood deposits in the southern canyon suggests that the wave broke over the southern caldera rim and quickly eroded through the welded tuff cap rock. A narrow slot canyon was carved into the caldera wall, catastrophically draining the lake. Additional wave cut terraces below the one marking the upper lake surface are lacking, suggesting that the lake drained rapidly.\"","StartYear":400,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":50,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Fisher","ParentVolcano":"Fisher","VolcanoID":"ak100","ParentVolcanoID":"ak100"},{"ID":3701,"Name":"Okmok 1500 yBP","Description":"From Beget and others (2005): \"Numerous post-caldera (younger than 2,000 years) pyroclastic flow and surge deposits are found associated with the young tuff cones within the caldera, and distal pyroclastic flow and surge deposits also occur on the west, north, and northeast flanks of Okmok Volcano as far as 14 kilometers from the caldera rim. The thickest set of young surge deposits outside of the caldera occurs on the west flank of Okmok about 8 kilometers from the caldera rim, where deposits of fine-grained surge beds containing incinerated plant remains and abundant accretionary lapilli are more than 6 meters thick. These deposits were emplaced about 1,500 years ago.\"","StartYear":450,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Okmok","ParentVolcano":"Okmok","VolcanoID":"ak206","ParentVolcanoID":"ak206"},{"ID":1991,"Name":"Augustine Long Beach Debris Avalanche","Description":"From Waitt and Beget (1996): \"Between about 1400 and 1100 yr B.P. (between tephra layers H and C) one debris avalanche swept to the sea on the south, another on the southwest, and perhaps a third on the north-northwest.\"\r\n\"A hummocky diamict is sparsely exposed in the distal southwest quarter as small kipukas surrounded by 1976 and older pumiceous lahar deposit and as an uninterrupted hummocky belt just beyond the limit of 1976 deposits. The humocks are as much as 9 m high and 20 in diameter, one of the largest consisting mostly of one 9-m andesite boulder. Numerous large boulders protruding through swampy terrain near the southwest coast probably are of this deposit. A lithic diamict exposed along Long Beach also includes hummocks exposing boulders as large as 6 m capped by tephra layers C and M. Large boulders be in matrix of smaller angular material of identical composition. Most of the lithic clasts are porphyritic andesite, but a few are sandstone. The avalanche must have flowed down across Jurassic sandstone (farther west than now exposed) en route to the coast. Detterman (1973) mistook the south-coastal exposure containing the 6-m boulder for in-situ lava flow.\"\r\n\"At low tide and on aerial photographs, large-boulder lag can be seen as far as 0.5 km off the south-southwest and southwest shore; maps show highly concoluted bathymetric contours here extending to a depth of 10 m as far as 2 km offshore, some 8.5 km from the summit. Similar submarine hummocky topography extends generally 6 to 9 kilometers outboard of demonstrable debris-avalanche deposits on other asimuths; such topography off the southwest coast must record the seaward extent of debris avalanche.\"\r\n\"In the southwest quarter 0.6 to 1.0 km back from the south coast is semicontinuous swamp nearly at sea level devoid of large hummocks but diversified by several large boulders. This low area may have been a lagoon in board of a debris avalanche that swept mostly to sea-like Northwest lagoon now behind West Island (see below). Younger pyroclastic and laharic deposits, including from 1935, 1964, and 1976 eruptions have nearly filled the former southwest lagoon. This much-buried Long Beach debris-avalanche deposit seems to extend a similar distance from the summit cone as the younger and well-preserved West Island debris-avalanche deposit (see below).\"\r\n\"The Long Beach debris-avalanche deposits (unit HCal) is perhaps only slightly older than the overlying pumiceous deposit (Southwest pyroclastic fan, unit HCpw), for in exposures along the eastern part of Long Beach where the pumiceous deposit directly overlies the lag there is no discernible soil at the top of the diamict.\"\r\n\"During this prehistoric period numerous domes must have been emplaced at the summit, repeatedly renewing the source for catastrophic debris avalanches. Remnants of these older domes form the east and south sides of the present summit-dome complex. Below the summit area at least three domes were emplaced on the upper flanks, one on the south (Karnishak dome), two on the northwest (domes \"I\" and \"H\"). Another undated and nearly buried dome or lava flow diversifies the upper south flank.\"","StartYear":480,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":160,"StartQualifierUnit":"Years","EndYear":840,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":70,"EndQualifierUnit":"Years","Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":2001,"Name":"Augustine Long Beach Pyroclastic Flow","Description":"From Waitt and Beget (1996): \"Between about 1400 and 1100 yr B.P. (between tephra layers H and C) one debris avalanche swept to the sea on the south, another on the southwest, and perhaps a third on the north-northwest. Pumiceous pyroclastic fans were shed to the southeast and southwest and lithic pyroclastic flows and lahars(?) to the south and southeast.\"\r\n\"A pumiceous sandy diamict as thick as 16 m overlies the Long Beach debris-avalanche deposit and an associated lahar deposit (units HCal and HClw) and directly underlying C tephra in coastal cliffs of the southwest flank. The pycroclastic deposit is 75-80 percent sand matrix: among the coarser casts three-quarters are pumice, one quarter lithics as large as 5 cm (rarely as large as 30 cm). The deposit is graded by density pumice clasts are concentrated in upper 3 m of deposit, lithic clasts in lower 10 m, though rare lithics lie throughout the deposit. The upper 3 m of the deposit is pale red, oxidized from high temperature. It has all the characteristics of pumiceous pyroclastic-flow deposit.\"\r\n\"During this prehistoric period numerous domes must have been emplaced at the summit, repeatedly renewing the source for catastrophic debris avalanches. Remnants of these older domes form the east and south sides of the present summit-dome complex. Below the summit area at least three domes were emplaced on the upper flanks, one on the south (Karnishak dome), two on the northwest (domes \"I\" and \"H\"). Another undated and nearly buried dome or lava flow diversifies the upper south flank.\"","StartYear":480,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":160,"StartQualifierUnit":"Years","EndYear":840,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":70,"EndQualifierUnit":"Years","Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":2011,"Name":"Augustine North Bench Debris Avalanche","Description":"From Waitt and Beget (1996): \"Between about 1400 and 1100 yr B.P. (between tephra layers H and C) one debris avalanche swept to the sea on the south, another on the southwest, and perhaps a third on the north-northwest.\"\r\n\"North Bench diamict comprises angular porphyritic andesite fragments as large as 3.5 m, bearing a mildly hummocky topography with local relief of 5 m. Seaward the deposit is truncated by a gently arcuate wave-cut scarp as high as 23 m, the highest near-coastal topographic feature along the west and north coasts. This sea cliff is now isolated 340 to 450 m from the sea by younger deposits that have flowed coastwise in the manner shown in figure 6c [in original text]. Beget and Kienle (1992) ignored the eastern part of this feature and lumped the western part with their Grouse Point debris-avalanche deposit. The North Bench bouldery diamict is probably a debris-avalanche deposit, but an origin by lahar or lithic pyroclastic flow cannot be disqualified.\"\r\n'North Bench diamict is geomorphically distinct from three neighboring debris-avalanche deposits: West Island, Grouse Point, Rocky Point (described below). The two segments of the arrested sea cliff truncating North Bench are nearly surrounded by theses younger diamicts. A straight scarp behind West Lagoon partly burned by West Island debris-avalanche deposit (see below) may be a west extension of this sea cliff.\"\r\n\"The North Bench diamict is overlain by a pyroclastic-flow deposit (undistinguished on map [in original text]) and by the Katmai 1912 ash and two older sand ashes. This tephra stratigraphy is about the same as that overlying the nearby clearly younger debris avalanche deposits such as at West Island and Grouse Point. But eh geomorphic expression including a nearly continuous straight sea cliff of moderate height well back from present coast indicates a much older age of the North Bench diamict, perhaps in the Hc or IH interval. Probably the overlying tephra stratigraphy is highly incomplete, perhaps because the veneering pyroclastic-flow deposit is itself much younger than the North Bench diamict.\"\r\n\"During this prehistoric period numerous domes must have been emplaced at the summit, repeatedly renewing the source for catastrophic debris avalanches. Remnants of these older domes form the east and south sides of the present summit-dome complex. Below the summit area at least three domes were emplaced on the upper flanks, one on the south (Karnishak dome), two on the northwest (domes \"I\" and \"H\"). Another undated and nearly buried dome or lava flow diversifies the upper south flank.\"","StartYear":480,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":160,"StartQualifierUnit":"Years","EndYear":840,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":70,"EndQualifierUnit":"Years","Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":2021,"Name":"Augustine South Point Debris Avalanche","Description":"From Waitt and Beget (1996): \"Between about 1400 and 1100 yr B.P. (between tephra layers H and C) one debris avalanche swept to the sea on the south, another on the southwest, and perhaps a third on the north-northwest.\"\r\n\"South Point, which just 0.6 km seaward of the general line of the south coast, consists of a diamict of angular clasts of porphyritic andesite as large as 6 m in intermediate diameter. Its hummocky surface has local relief of 10 m. Clearly a debris-avalanche deposit, it has no discernable levees upslope, where it has been deeply buried by younger eruption deposits, especially in 1963-64.\"\r\n\"Like the geomorphic relation at Northeast Point, the South Point debris avalanche overrode and partly buried a sea cliff that now lies 200 m back from South Point. The sharply hummocky topography is similar both seaward and behind the arrested sea cliff. The present sea cliff (seaward of buried one) is 30 m high, the minimum thickness of South Point debris-avalanche deposit there. That South Point is far broader and projects much farther seaward than Northeast Point suggests the latter’s greater age, consistent with tephra stratigraphy.\"\r\n\"The tephra-and-humus sequence that overlies the debris-avalanche deposit ranges from 0 to 8 m thick, typically 1-2 m thick, having the C tephra at its base. Though this is the youngest of the large debris avalanches forming Augustine’s south and east coast, it too is eroded back into a high cliff. It is thus geomorphically much older than any of the uncliffed debris-avalanche deposits on the northwest and north coasts.\"\r\n\"During this prehistoric period numerous domes must have been emplaced at the summit, repeatedly renewing the source for catastrophic debris avalanches. Remnants of these older domes form the east and south sides of the present summit-dome complex. Below the summit area at least three domes were emplaced on the upper flanks, one on the south (Karnishak dome), two on the northwest (domes \"I\" and \"H'). Another undated and nearly buried dome or lava flow diversifies the upper south flank.\"","StartYear":480,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":160,"StartQualifierUnit":"Years","EndYear":840,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":70,"EndQualifierUnit":"Years","Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":2031,"Name":"Augustine Southeast Pyroclastic Fan","Description":"From Waitt and Beget (1996): \"Between about 1400 and 1100 yr B.P. (between tephra layers H and C) one debris avalanche swept to the sea on the south, another on the southwest, and perhaps a third on the north-northwest. Pumiceous pyroclastic fans were shed to the southeast and southwest and lithic pyroclastic flows and lahars(?) to the south and southeast.\"\r\n\"On the south-southeast coast a pumiceous pycroclastic-flow deposit (unit HCpe) is exposed only in section in lower part of the sea cliff. Farther east at southeast point a lithic pyroclastic-flow (and lahar?) deposit (unit HClc) consists of cobble gravel to sandy cobble gravel that is vaguely stratified and lacking in large boulders, suggestive of a laharic or pyroclastic-flow deposit. Upslope from Southeast Point a proximal facies (unit HClp) contains numerous angular lithic (dense) porphyritic-andesite boulders in 4-6 m range and a few as large as 9 m. Some smaller dense blocks are prismatically jointed, revealing that the flow originated as hot dome rock. Surface texture of both facies is coarsely lobate and leveed with a relatively gentle local relief as much as 2.5 m-the morphology not of debris avalanche but of lithic pyroclastic flow (or lahar?). The unusually large size of some blocks (for a pyroclastic-flow deposit) is due to the steep slope (24 degrees) and short distance (2.2 to 3.2 km) between the summit and the deposit. Both the coastal and the proximal facies are overlain by the C tephra, the coastal facies underlain by the H tephra.\"\r\n\"During this prehistoric period numerous domes must have been emplaced at the summit, repeatedly renewing the source for catastrophic debris avalanches. Remnants of these older domes form the east and south sides of the present summit-dome complex. Below the summit area at least three domes were emplaced on the upper flanks, one on the south (Karnishak dome), two on the northwest (domes \"I\" and \"H\"). Another undated and nearly buried dome or lava flow diversifies the upper south flank.\"","StartYear":480,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":160,"StartQualifierUnit":"Years","EndYear":840,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":70,"EndQualifierUnit":"Years","Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":1981,"Name":"Augustine Tephra H","Description":"From Waitt and Beget (2009): \"The lowest five coarse-pumice beds at the coast-tephras G, I, H, C, and O-drifted east and southeast. Tephra G and ambiguous tephra O are known only from a few sites each on the east and southeast, neither with enough data points to warrant a map. Drawn from data at many stratigraphic exposures, isopach maps clearly show tephras I, H, and C drifted east-southeast and southeast.\"\r\n\"Several decimeters of thin beds of fine sand to silt (ash) separate tephra layers I and H (fig. 6 [in original text]).\"\r\nFrom Tappen and others (2009): \"...tephra H is a 8- to 9-cm thick layer of fine-grained gray silty ash with pumiceous lapilli.\"","StartYear":500,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":50,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":3901,"Name":"Great Sitkin 1300 yBP","Description":"From Waythomas and others (2003): \"Lahar deposits in Sitkin Creek vally; Pumice lapilli tephra deposits.\"","StartYear":650,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":800,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":2731,"Name":"Kanaga T9","Description":"From Waythomas and others (2001): \"Groups of tephra deposits so defined indicate that at least 11 eruptions of Kanaga Volcano have occurred since about 11 ka. Most of these eruptions were probably sub-Plinian to Plinian, producing moderately vesicular dacitic pumice lapilli tephra deposits ranging in thickness from a few centimeters to more than 1 m (table 2 [in original text]).\"\r\n\"Pumice-lapilli fall/flow deposit.\"","StartYear":657,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1025,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kanaga","ParentVolcano":"Kanaga","VolcanoID":"ak144","ParentVolcanoID":"ak144"},{"ID":2071,"Name":"Augustine Tephra O","Description":"From Waitt and Beget (2009): \"Between tephras C and M a seventh tephra O-rare and in most places missing, its origin and significance obscure-we eventually dropped as a reliable marker bed but it shows in certain measured sections (plate 2 [in original text]). These coarse tephra layers also contain 10 to 40 volume percent lithic andesite fragments smaller than pumice fragments. Isopach maps, drawn from thickness measured mostly at coastal exposures, show the azimuths to which five of the coarse layers drifted (fig. 7 [in original text]).\"\r\n\"The lowest five coarse-pumice beds at the coast-tephras G, I, H, C, and O-drifted east and southeast. Tephra G and ambiguous tephra O are known only from a few sites each on the east and southeast, neither with enough data points to warrant a map.\"","StartYear":755,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":120,"StartQualifierUnit":"Years","EndYear":1240,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":50,"EndQualifierUnit":"Years","Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":1551,"Name":"Mt Churchill White River East Lobe","Description":"From Preece and others (2014): \"The White River Ash (WRA) is an important Holocene chronostratigraphic marker through-out eastern Alaska (USA) and in Yukon and western Northwest Territories (Canada) (Lerbekmo and Campbell, 1969; Pewe, 1975), and provides age control for peat studies (Harris and Schmidt, 1994; Robinson and Moore, 1999, 2000), glacial fluctuations (Denton and Karlen, 1977), paleoecological studies (Slater, 1985), and archaeological and anthropological studies (Workman, 1979; Moodie and others, 1992) (Fig. 1 [in original text]). WRA has been defined by its geographic distribution and its stratigraphic position, combined with radiocarbon dating, with less emphasis on its petrographic and geochemical features. The northern lobe erupted between A.D. 150 and 500 (Jensen and Froese, 2006) or ca. 1900 yr B.P. (Lerbekmo and others, 1975), while the eastern lobe erupted A.D. 803 or 1147 cal. yr B.P. (Clague and others, 1995). Cryptotephra studies in lake and peat cores have extended the distribution of the eastern lobe to southeastern Alaska (sites A-C, Fig. 1 [in original text]), northern British Columbia (site D, Fig. 1 [in original text]), Newfoundland, northern Europe, and Greenland (Lakeman and others, 2008; Payne and others, 2008; Addison and others, 2010; Pyne-O’Donnell and others, 2012; Jensen and others, 2012).\"\r\n\"The exact vent area of the WRA has been disputed, and two possible locations have been suggested. Lerbekmo and Campbell (1969) postulated that the WRA vent was located on the floor of a deep valley beneath the Klutlan Glacier near what they identified as a large pumice mound (4 in Fig. 2 [of original text]). McGimsey and others (1992) and Richter and others (1995) questioned the likelihood of a vent located at the floor of a valley lacking an edifice or nearby volcano, and proposed that Mount Churchill was the vent. Lerbekmo (2008) questioned whether Mount Churchill was a volcano, and reiterated that the vent for WRA was underneath the Klutlan Glacier.\"\r\nFrom Richter and others (1995): \"The White River Ash is a bilobate Plinian fallout deposit covering more than 340,000 km square and containing an estimated 25-50 km cubed of tephra (bulk volume) (Bostock 1952; Berger 1960) (Fig. 1 [in original text]).\"\r\nFrom Lerbekmo and others (1975): \"A northern lobe and an eastern lobe have axis lengths in excess of 500 and 1000 km respectively.\"\r\n\"Unfortunately, glass compositions are similar in the northern and eastern lobes of the WRA tephra, and published analyses cover a significant range, making it difficult to assign a particular tephra sample to a specific lobe (Addison and others, 2010; Payne and others, 2008; Lakeman and others, 2008; Froese and Jensen, 2005; Richter and others, 1995; Beget and others, 1992; Downes, 1985).\"\r\n\"Tephra samples of the WRA contain phenocrysts of plagioclase, amphibole, magnetite, ilmenite, and trace amounts of orthopyroxene and apatite within highly vesicular, frothy color-less glass (Table S8 in the Supplemental File [see footnote 1] [in original text]). Biotite occurs in the eastern lobe in trace amounts (\u003c~1%) in some pumice clasts from locations 4 and 6 (Fig. 2 [in original text]).\"\r\n\"Previous studies have demonstrated that the eastern and northern lobes of the WRA have different ilmenite compositional ranges (Lerbekmo and others, 1975; Downes, 1985; Richter and others, 1995) and this distinction has been used to define geochemical groups WRA-E and WRA-N.\"\r\n\"WRA deposits can be assigned to WRA-E or WRA-N, and are best identified using ilmenite compositions...Within WRA-E, WRA-Ea is clearly older than WRA-Eb. The 1147 cal yr B.P. (Clague and others, 1995) WRA-Ea deposits either do not show or only weakly display systematic changes in glass or Fe-Ti oxide composition with stratigraphic position. On geochemical plots, WRA-Eb samples are on linear extensions toward higher silica content and lower temperature estimates compared to WRA-Ea samples, strongly suggesting a genetic link. WRA-Eb samples represent a younger eruption or eruptions from the evolving Mount Churchill magmatic system.\"\r\nFrom Payne and others (2008): \"The LNA 100 tephra shows geochemical similarity to WRA tephra. Dating evidence does not show a consistent sequence of radiocarbon dates but samples from peat containing the ash layer suggest that the tephra was deposited between approximately 1260 and 1375 cal yr BP. The most likely origin of this tephra is therefore one of the WRA eruptions, most probably the younger, eastern lobe event. Clague et al. (1995) presented ten radiocarbon assays on this tephra spanning 791 to 1416 cal yr BP and opted for a weighted mean of four of these dates to assign the eruption an age estimate of ca. 1147 cal yr BP. The dates in this study would suggest an older date for this tephra, although this conclusion is complicated by the dates being out of sequence (Table 6 [in text]).\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2017) reports a magnitude of 6.1, bulk eruptive volume of 50 cubic km and a dense rock equivalent eruptive volume of 23 cubic km for the eruption.","StartYear":803,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Churchill, Mt","ParentVolcano":"Churchill, Mt","VolcanoID":"ak50","ParentVolcanoID":"ak50"},{"ID":3091,"Name":"Spurr 1110 yBP","Description":"From Waythomas and Nye (2002): \"A relatively large explosive eruption of Crater Peak is recorded by a 40-centimeter-thick pumiceous lapilliash that is younger than about 840 years but older than A.D. 1953.\"","StartYear":840,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1953,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Spurr","ParentVolcano":"Spurr","VolcanoID":"ak260","ParentVolcanoID":"ak260"},{"ID":2041,"Name":"Augustine Tephra C","Description":"From Waitt and Beget (1996): \"Exposed on the steeply eroded sides of three south-side inlier kipukas at altitudes 250-700 m are 8-10-m sections comprising several beds of pumiceous and lithic pyroclastic-fiow deposits interbedded with many beds of loose, sorted pumiceous fall deposit. The uppermost pumiceous fall beds probably correlate with tephras M, C, and perhaps with other tephra beds of the coastal sections, though ambiguous field character and ambiguous chemical data make such correlations tenuous. Yet a radiocarbon age of about 2160 yr B.P. (table 2 [in original text]) from the upper midsection (below the upmost few tephra layers) at the eastmost such section supports the tenuous correlation.\"\r\nFrom Waitt and Beget (2009): \"The lowest five coarse-pumice beds at the coast-tephras G, I, H, C, and O-drifted east and southeast. Tephra G and ambiguous tephra O are known only from a few sites each on the east and southeast, neither with enough data points to warrant a map. Drawn from data at many stratigraphic exposures, isopach maps clearly show tephras I, H, and C drifted east-southeast and southeast.\"\r\n\"Glass separates of tephras C and M are chemically nearly identical-as close as replicate microprobe analyses of either tephra C or tephra M alone. Correlation of tephras between separated localities is thus mainly by field stratigraphy, in some places strengthened or augmented by the microprobe data.\"\r\n\"Tephra C in places comprises three coarse horizons and commonly is a couplet of coarser beds separated by finer material.\"\r\nFrom Tappen and others (2009): \"Tephra layer C comprises two units including upper (C2) and lower (C1) fall deposits that possibly represent two phases of the same eruption (R. Waitt pers. comm., 2004). Unit C1 is a light gray, coarse-grained, andesitic, normally graded tephra deposit that is 60-70 cm thick and overlies soil. The overlying C2 tephra unit is 12-15 cm thick and shows distinct reverse grading with the largest pumice fragments at the top. Mingling of some prehistoric magmas occurred, because one C2 clast consists of white pumice containing bands of much darker volcanic rock.\"","StartYear":850,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":100,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":3081,"Name":"Shishaldin 1000 yBP","Description":"From Beget and others (2002): \"A representative sequence of tephra deposits on the north side of Shishaldin Volcano, near the lower limit of modern glaciers, occurs above a young lava flow radiocarbon dated to about 1,000 years B.P. (Beget and others, 1998).\"","StartYear":950,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":3141,"Name":"Spurr 1000 yBP","Description":"From Waythomas and Nye (2002): \"These deposits [mid-Holocene pyroclastic flow and lahar deposits] are overlain by a several-meters-thick soils-tephra sequence. The buried soils are rich in organic materials, and the tephra consists of thin (less than 1-centimeter-thick), fine-grained volcanic-ash deposits that probably record small explosive eruptions of Crater Peak about 1,000 years ago (fig. 5 [in original text]).\"","StartYear":950,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Spurr","ParentVolcano":"Spurr","VolcanoID":"ak260","ParentVolcanoID":"ak260"},{"ID":3861,"Name":"Shishaldin Post 1000 Tephra","Description":"From Beget and others (2002): \"A representative sequence of tephra deposits on the north side of Shishaldin Volcano, near the lower limit of modern glaciers, occurs above a young lava flow radiocarbon dated to about 1,000 years B.P. (Beget and others, 1998).\"","StartYear":950,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":2051,"Name":"Augustine Lahar West of Southeast Point","Description":"From Waitt and Beget (1996): \"Between about 1000 and 700 yr B.P. (between tephra layers C and M) pyroclastic flows, pyroclastic surges, and lahars swept the west and south flanks.\"\r\n\"A lithic lahar (unit CMl) as thick as 2.5 m poured down a broad paleoswale west of Southeast Point. Similar flows poured across the Jurassic bedrock block and channeled down Middle and East Kamishak Creeks to overtop part of South Point debris-avalanche deposit. At the mouth of Middle Kamishak creek the deposit is eroded back into a sea cliff that descends east from 50 to 30 m high with the slope of the fan surface.\"\r\n\"During this prehistoric period numerous domes must have been emplaced at the summit, repeatedly renewing the source for catastrophic debris avalanches. Remnants of these older domes form the east and south sides of the present summit-dome complex. Below the summit area at least three domes were emplaced on the upper flanks, one on the south (Karnishak dome), two on the northwest (domes \"I\" and \"H'). Another undated and nearly buried dome or lava flow diversifies the upper south flank.\"","StartYear":950,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":100,"StartQualifierUnit":"Years","EndYear":1240,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":50,"EndQualifierUnit":"Years","Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":2061,"Name":"Augustine Pyroclastic Flow West of Augustine Creek","Description":"From Waitt and Beget (1996): \"Between about 1000 and 700 yr B.P. (between tephra layers C and M) pyroclastic flows, pyroclastic surges, and lahars swept the west and south flanks.\"\r\n\"In a coastal gully 300 m west of Augustine Creek, a sandy pumiceous pyroclastic-flow deposit (unit CMp) 0-3 m thick underlies the M(?) tephra and overlies the thick, oxidized pumiceous pyroclastic-flow deposit of \"southwest pyroclastic fan\" (unit Hcpw). One site reveals two massive deposits-a lower one 13 m thick with gas-escape pipes and an upper one 4 m thick-separated by 20 cm of apparently fluvial deposit lacking a paleosol. These flows probably followed Augustine Creek when and spilled through a western swale. This unit, apparently scarcely eroded, pinches out about 0.5 km west of the creek: its overbank spillage was thus limited to the vicinity of present creek.\"\r\n\"During this prehistoric period numerous domes must have been emplaced at the summit, repeatedly renewing the source for catastrophic debris avalanches. Remnants of these older domes form the east and south sides of the present summit-dome complex. Below the summit area at least three domes were emplaced on the upper flanks, one on the south (Karnishak dome), two on the northwest (domes \"I\" and \"H\"). Another undated and nearly buried dome or lava flow diversifies the upper south flank.\"","StartYear":950,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":100,"StartQualifierUnit":"Years","EndYear":1240,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":50,"EndQualifierUnit":"Years","Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":2081,"Name":"Augustine Tephra M","Description":"From Waitt and Beget (1996): \"Exposed on the steeply eroded sides of three south-side inlier kipukas at altitudes 250-700 m are 8-10-m sections comprising several beds of pumiceous and lithic pyroclastic-fiow deposits interbedded with many beds of loose, sorted pumiceous fall deposit. The uppermost pumiceous fall beds probably correlate with tephras M, C, and perhaps with other tephra beds of the coastal sections, though ambiguous field character and ambiguous chemical data make such correlations tenuous. Yet a radiocarbon age of about 2160 yr B.P. (table 2 [in original text]) from the upper midsection (below the upmost few tephra layers) at the eastmost such section supports the tenuous correlation.\"\r\nFrom Waitt and Beget (2009): \"Of the two youngest coarse tephras, M drifted south and B strongly northeast (fig. 7 [in original text]).\"\r\n\"Glass separates of tephras C and M are chemically nearly identical-as close as replicate microprobe analyses of either tephra C or tephra M alone. Correlation of tephras between separated localities is thus mainly by field stratigraphy, in some places strengthened or augmented by the microprobe data.\"\r\n\"On the south and west, tephra M seems everywhere much thicker than tephra B.\"","StartYear":950,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":100,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":2741,"Name":"Kanaga T10","Description":"From Waythomas and others (2001): \"Groups of tephra deposits so defined indicate that at least 11 eruptions of Kanaga Volcano have occurred since about 11 ka. Most of these eruptions were probably sub-Plinian to Plinian, producing moderately vesicular dacitic pumice lapilli tephra deposits ranging in thickness from a few centimeters to more than 1 m (table 2 [in original text]).\"\r\n\"Pumice-lapilli fall deposit.\"","StartYear":1019,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1276,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kanaga","ParentVolcano":"Kanaga","VolcanoID":"ak144","ParentVolcanoID":"ak144"},{"ID":1241,"Name":"Aniakchak Tuff Cones","Description":"From Bacon and others (2014): \"The three tuff cones on the eastern caldera floor were constructed by alternating Surtseyan and hydrovolcanic explosions. Eruption of the basaltic andesite Windy and Breezy Cones on the ring-fracture system, and of andesitic Surprise Cone inboard from them, may be related to unloading of the magmatic system by sudden lowering of the intracaldera lake by ~200 m ca. 1,860 14C yr B.P.\"\r\n\"Three breached tuff cones form subdued arcuate ridges of bedded phreatomagmatic tephra on the eastern part of the caldera floor (fig. 10A [in original text], unit Qtc). Embraced and nearly surrounded by younger Vent Mountain lava flows, Surprise, Windy, and Breezy Cones rise ~120 m above the surrounding terrain to define 500-1,000-m-diameter explosion craters (figs. 12A and B [in original text]). Two samples of juvenile scoria from Surprise Cone have 57.9 and 58.4 weight percent SiO2, while single analyses of scoria from Windy and Breezy Cones yield 55.3 and 52.3 weight percent SiO2, respectively. Based on the similar appearances of the tuff cones, we infer that they all are roughly similar in age. Radiocarbon dating of a soil above lapilli tephra of Surprise Cone-like chemistry (NA97-6A) returned a weighted mean age of 900+/-80 yr B.P. (tables 1 and 2 [in original text]), giving a minimum age for Surprise Cone. Superposition relationships are unclear, although Windy Cone tephra appear to overlap Breezy Cone. The tuff cones have not been dated directly but are thought to postdate catastrophic draining of the caldera lake to approximately their elevation. Lacustrine clayey silt and sand are present in the breach of Surprise Cone and on a wave-cut terrace north of Surprise Lake at 1,226 ft (374 m) asl (McGimsey and others, 1994). Eruptions responsible for the tuff cones likely took place in shallow water, as suggested by the sediments within Surprise Cone. The basaltic andesite to andesite eruptions may well have been facilitated by unloading that resulted from rapid draining of the ancestral caldera lake to about the ~1,400-ft (430 m) elevation of Surprise and Windy Cone craters, although we cannot rule out the possibility that the tuff cone eruptions occurred earlier, during filling of the lake. Two well-preserved maar craters southeast of Windy cone demonstrate that phreatic or phreatomagmatic explosions occurred in the recent past, presumably under hydrologic conditions similar to present time. A third explosion crater, which also evidently did not produce juvenile ejecta and probably is unrelated to ascent of mafic magma, is approximately midway between Vent Mountain and Half Cone (fig. 10A [in original text]).\"","StartYear":1050,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":80,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":3151,"Name":"Spurr 840 yBP","Description":"From Waythomas and Nye (2002): \"Lahar deposits that overlie the soil-tephra sequence were probably generated by pyroclastic flows during one or two eruptions about 840 years ago.\"","StartYear":1110,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Spurr","ParentVolcano":"Spurr","VolcanoID":"ak260","ParentVolcanoID":"ak260"},{"ID":1251,"Name":"Aniakchak Half Cone Lower Pumice","Description":"From Bacon and others (2014): \"Pumice-fall and pyroclastic-flow deposits from Half Cone are exposed in the north wall of the 1931 Main Crater 2 km to the south (fig. 13D [in original text]). Here, the cliff at the base of the section (fig. 13E [in original text]) is composed of \u003e22 m of partly welded or indurated coarse pyroclastic-flow material, much like spatter-rich pyroclastic-flow deposits at Santorini (Mellors and Sparks, 1991), containing andesite bombs as large as 0.6 m × 2 m and similar in composition to Half Cone pyroclasts (59 weight percent SiO2). This unit is overlain by 13 m of pumiceous cross-bedded surge layers, 31 m of pumice-fall deposits, 5 m of Half Cone ca. 400 yr B.P. spatter agglutinate, and an 81-m-thick section of 1931 materials (Nicholson and others, 2011, their figure 3F). Dacite tephra older than the Pink Pumice and considered to have a Half Cone source, and which therefore may be correlative with proximal deposits at Half Cone and with the section exposed in the 1931 Main Crater, have weighted mean radiocarbon ages of 840+/-40 and 570+/-40 yr B.P. (tables 1 and 2  [in original text], lower and upper light pumice, respectively).\"","StartYear":1110,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":40,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":1261,"Name":"Aniakchak Vent Mountain Tephra","Description":"From Bacon and others (2014): \"Vent Mountain scoria and spatter cone is the most prominent topographic feature within the caldera (figs. 10, 12C and 12D [in original text]). The cone rises 440-530 m above the caldera floor to an elevation of 3,350 ft (1,021 m). The 210-m-deep summit crater has a diameter of ~800 m. Numerous blocky lava flows emanate from the cone's lower flanks and from a prominent fissure vent that cuts the southwest flank. Although some outcrops of basaltic andesite and mafic andesite lava west of The Gates and in the larger maar crater possibly had source vents now hidden beneath Vent Mountain, the majority of products attributed to that volcano are silicic andesite and dacite.\"\r\n\"Tephra compositionally similar to Vent Mountain lava is stratigraphically above Half Cone lower light pumice (weighted mean age 840+/-30 yr B.P., table 1 [in original text]) and below Half Cone upper light pumice (weighted mean age 570+/-40 yr B.P., table 1 [in original text]) in a section 6 km east-southeast of the caldera (table 2 [in original text]).\"","StartYear":1110,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":30,"StartQualifierUnit":"Years","EndYear":1380,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":40,"EndQualifierUnit":"Years","Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":2091,"Name":"Augustine West Lagoon Debris Avalanche","Description":"From Waitt and Beget (1996): \"Between about 700 and 400 yr B.P. (between tephra layers M and B) a debris avalanche swept to the sea on the west and a small one on the south-southeast. Large lithic pyroclastic flows shed to the southeast; smaller ones descended exiting swales on the southwest and south.\"\r\n\"Lagoon debris-avalanche deposit has a hummocky topography with local relief of 10 m and contains angular andesite boulders at least as large as 3 m. In coastal exposures it is overlain by about 60cm of organic debris and tephra, at whose contact a discontinuous pumice lapilli, apparently tephra B. The deposit has a conspicuous left-lateral levee built over a lithic pyroclastic-flow deposit (unit Mbp) to the south, which is capped by tephra B and underlain by tephra M. Part of the hummocky Lagoon debris-avalanche deposit, though, lies outside (south of) this levee, which suggests that the avalanche arrived in at least two closely spaced pulses.\"\r\n\"The West Island debris-avalanche deposit partly buries the north side of Lagoon debris-avalanche deposit, banked against an apparent sea cliff eroded into the Lagoon deposit. A nearly continuous sea cliff inside of Northwest Lagoon, overridden and modified by the West Island debris avalanche, is perhaps a segment of these same sea cliffs.\"\r\n\"During this prehistoric period numerous domes must have been emplaced at the summit, repeatedly renewing the source for catastrophic debris avalanches. Remnants of these older domes form the east and south sides of the present summit-dome complex. Below the summit area at least three domes were emplaced on the upper flanks, one on the south (Karnishak dome), two on the northwest (domes \"I' and 'H\"). Another undated and nearly buried dome or lava flow diversifies the upper south flank.\"","StartYear":1180,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":50,"StartQualifierUnit":"Years","EndYear":1570,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":20,"EndQualifierUnit":"Years","Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":2101,"Name":"Augustine Southeast Beach Debris Avalanche","Description":"From Waitt and Beget (1996): \"Between about 700 and 400 yr B.P. (between tephra layers M and B) a debris avalanche swept to the sea on the west and a small one on the south-southeast. Large lithic pyroclastic flows shed to the southeast; smaller ones descended exiting swales on the southwest and south.\"\r\n\"A boulder diamict exposed in upper part of bluffs along Southeast beach (unit MBas) is studded with angular in situ blocks as large as 2.5 m, as large as 6 m as lag on beach, and as large as 7 m in the surf zone seaward. The diamict is overlain by B tephra and underlain by M and C tephras. These tephras overlie unit HCpe that forms most of bluff. Adjacent lahar or pyroclastic-flow deposits (units MBlp and MBpl) are flatter surfaced and contain angular lithic andesite clasts no larger than 2 m.\"\r\n\"During this prehistoric period numerous domes must have been emplaced at the summit, repeatedly renewing the source for catastrophic debris avalanches. Remnants of these older domes form the east and south sides of the present summit-dome complex. Below the summit area at least three domes were emplaced on the upper flanks, one on the south (Karnishak dome), two on the northwest (domes \"I' and \"H\"). Another undated and nearly buried dome or lava flow diversifies the upper south flank.\"","StartYear":1190,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":60,"StartQualifierUnit":"Years","EndYear":1570,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":20,"EndQualifierUnit":"Years","Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":2111,"Name":"Augustine West Lagoon Pyroclastic Flow/Lahar","Description":"From Waitt and Beget (1996): \"Between about 700 and 400 yr B.P. (between tephra layers M and B) a debris avalanche swept to the sea on the west and a small one on the south-southeast. Large lithic pyroclastic flows shed to the southeast; smaller ones descended exiting swales on the southwest and south.\"\r\n\"Atop a sea cliff now isolated along the inner margin of West lagoon is a 4-m massive cobbly sand, apparently lithic pyroclastic-flow (or lahar?) deposit (unit MBplo). It is capped by B (?) tephra, which at one site is underlain by M (?) tephra. Upslope at altitudes 40-90 m the deposit is far more boulder and diversified by intricately lobate termini (unit MBpli). The outboad portion formerly extended at least 300 m seaward into West lagoon, its legacy a lag of boulders as large as 2.5 m. This wave erosion must have occurred during the M-B period, after which a growing sand spit enclosed the lagoon and isolated the sea cliff from ocean waves.\"\r\n\"During this prehistoric period numerous domes must have been emplaced at the summit, repeatedly renewing the source for catastrophic debris avalanches. Remnants of these older domes form the east and south sides of the present summit-dome complex. Below the summit area at least three domes were emplaced on the upper flanks, one on the south (Karnishak dome), two on the northwest (domes \"I\" and \"H\"). Another undated and nearly buried dome or lava flow diversifies the upper south flank.\"","StartYear":1190,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":60,"StartQualifierUnit":"Years","EndYear":1570,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":20,"EndQualifierUnit":"Years","Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":3891,"Name":"Great Sitkin 700 yBP","Description":"From Waythomas and others (2003): \"Lahar deposits in Sitkin Creek valley; Pumice lapilli tephra deposits.\"","StartYear":1250,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1400,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":2751,"Name":"Kanaga T11","Description":"From Waythomas and others (2001): \"Groups of tephra deposits so defined indicate that at least 11 eruptions of Kanaga Volcano have occurred since about 11 ka. Most of these eruptions were probably sub-Plinian to Plinian, producing moderately vesicular dacitic pumice lapilli tephra deposits ranging in thickness from a few centimeters to more than 1 m (table 2 [in original text]).\"\r\n\"Pumice-lapilli fall deposit.\"","StartYear":1329,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1445,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kanaga","ParentVolcano":"Kanaga","VolcanoID":"ak144","ParentVolcanoID":"ak144"},{"ID":1431,"Name":"Akutan Cascade Bight Valley Lahars","Description":"From Waythomas and others (1998): \"At least one lahar deposit and a sequence of thin, black, sandy ash layers in Cascade Bight (fig. 3 [in original text]) document minor eruptive activity directed down this valley 470 to 600 years ago. One or more of the lahars found in Flat Bight may be correlative with this period of eruptive activity.\"\r\nFrom Waythomas (1999): \"Cascade Bight valley is south of Akutan caldera, on the Pacific Ocean side of the island (Fig. 1 [in original text]). The valley heads on the volcano flank, and lahar and tephra deposits are exposed in several locations throughout the valley (Fig. 10 [in original text]). A compact, gray, massive, matrix-supported, noncohesive lahar deposit with angular to subrounded cobble and finer lithic clasts of andesite is present at sections 56, 57, 41, 4la, and 82 (Fig. 10 [in original text]). This basal gray lahar deposit underlies much of Cascade Bight valley and likely extends to the coast.\"\r\n\"The basal gray lahar is overlain by a sequence of interbedded fine, light-colored (distal?) ash beds, black sandy tephras, and sand-and-cobble alluvium that accumulated on a former flood plain. Organic detritus from the base of the ash and alluvium sequence at section 82 (Fig. 10 [in original text]) yielded a radiocarbon age of 630+/-110 years B.P. (Table 1 [in original text]). Soil-organic matter from a buried soil at the top of a correlative sequence of ash and alluvium at section 41a (Fig. 10 [in original text]) yielded a radiocarbon age of 25+/-80 years B.P. and is considered modern (Table 1 [in original text]). A third radiocarbon age on soil organic matter from a buried A/Cox soil developed on tephra that overlies the basal gray lahar is 395+/-125 years B.P. (section 56, Fig. 10 [in original text]; Table 1 [in original text]). These dates indicate that Cascade Bight valley was inundated by at least one noncohesive lahar more than 500-600 years ago. The Akutan tephra was not found in Cascade Bight valley, and it is not known if the basal gray lahar deposit is part of the eruption sequence associated with the tephra. This lahar deposit is similar to others that overlie the Akutan tephra and are associated with the caldera-forming eruption.\"","StartYear":1350,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1480,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":1271,"Name":"Aniakchak Half Cone Upper Pumice","Description":"From Bacon and others (2014): \"Pumice-fall and pyroclastic-flow deposits from Half Cone are exposed in the north wall of the 1931 Main Crater 2 km to the south (fig. 13D [in original text]). Here, the cliff at the base of the section (fig. 13E [in original text]) is composed of \u003e22 m of partly welded or indurated coarse pyroclastic-flow material, much like spatter-rich pyroclastic-flow deposits at Santorini (Mellors and Sparks, 1991), containing andesite bombs as large as 0.6 m x 2 m and similar in composition to Half Cone pyroclasts (59 weight percent SiO2). This unit is overlain by 13 m of pumiceous cross-bedded surge layers, 31 m of pumice-fall deposits, 5 m of Half Cone ca. 400 yr B.P. spatter agglutinate, and an 81-m-thick section of 1931 materials (Nicholson and others, 2011, their figure 3F). Dacite tephra older than the Pink Pumice and considered to have a Half Cone source, and which therefore may be correlative with proximal deposits at Half Cone and with the section exposed in the 1931 Main Crater, have weighted mean radiocarbon ages of 840+/-40 and 570+/-40 yr B.P. (tables 1 and 2 [in original text], lower and upper light pumice, respectively).\"","StartYear":1380,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":40,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":3271,"Name":"Ugashik-Peulik Upper Grey Ash","Description":"From Fierstein (2007): \"The youngest pre-1912 tephras widely preserved in and near the lower Valley of Ten Thousand Smokes are a pair of thin, fine-grained, grey to grey-tan ash layers sandwiched between the 1912 fall and a distinctive orange-stained dacite lapilli fall (described below [in original text]). Where best preserved in the lower VTTS, the younger of the two is typically 1.5 cm thick (ranging from 0.5 to 3.5 cm, Fig. 6 [in original text]) although it is not uncommonly expressed as discontinuous grey lenses or wisps of grey fine ash (a little gritty to touch) aligned in the enclosing soil. Its dominant crystals are plagioclase and two pyroxenes, with an opx/cpx ratio of 20:1 (Table 1 [in original text]). Because of its wide preservation here (even though it is thin), and because the ash is gritty (rather than silty), the source was originally presumed to be local. However, microprobe data for glass and Fe-Ti oxides (Fig. 7 [in original text]), permit this ash to be correlated with a grey ash layer found as far as 42 km to the southeast (beyond Mount Katmai) and ∼30 km SSE in Martin Creek (Fig. 6 [in original text]). In almost all sections south of the volcanic axis this layer is a slightly gritty ash about 1 cm thick, with no obvious thinning or fining trends to indicate the source vent. An exception is in the well-preserved peat section in Angle Creek (Fig. 3 [in original text]) where the uppermost ash is actually a composite of two grey ashfalls, the lower (2 cm) of which is fine ash and the upper (1.5 cm) is medium ash, each including a 0.5-cm cap of very fine vitric silt. These sublayers appear to represent two pulses of the same eruption, as microprobe data for the young grey ash at 15 other locations indicate correlation, with the single layer being a more distal expression of the more proximal Angle Creek sublayers.\"\r\n\"Glass analyses suggest this eruption was compositionally zoned, with silicic and mafic components represented in the analyzed shards (Fig. 7a [in original text]). It is possible that the two sublayers in Angle Creek represent separate mafic and silicic pulses, but samples are not in hand to test that possibility. Of the 14 upper grey ash samples analyzed, three have only silicic glass (∼64 to 68 wt.% SiO2; 3 to 4wt.% CaO), two have only mafic glass (∼57 to 64 wt.% SiO2; 7 to 5 wt.% CaO), and nine have glass representing that entire range. Similarly, magnetite analyses of eight of these samples, both mafic and silicic (Fig.7b [in original text]), have distinctive MgO-TiO2 trends (MgO ∼2.7 to 4.3 wt.%); two samples have MgO from 1.2 to 2.8 wt.%, and five samples, including the one from Angle Creek, have magnetite that plots in both groups. Although the subordinate population of lower-MgO magnetite is similar to other Katmai group tephras, the higher-MgO magnetite is distinct from all other locally derived fall layers yet analyzed. Considering this, and the 3.5-cm thickness and two-layer stratigraphy preserved in Angle Creek-west of all the Katmai volcanoes studied-suggests the vent for this ashfall was westward. In agreement, the fairly constant ∼1-cm thickness measured over a wide area around the Katmai group of volcanoes suggests this ash was not locally derived. In contrast, the gritty (not silty) grain size suggests the source could not have been too far away. Mount Peulik, the next young stratovolcano, 95 km SW down the volcanic chain from Mount Katmai, seems a likely source. If so, Millers (2004) descriptions of Mount Peulik narrow the possible source of this upper grey ash to the opx-rich lavas of the present steep-sided cone, because older flows and younger domes include hornblende and biotite, which are not present in this tephra.\"\r\n\"Seven of the radiocarbon dates for soils beneath this ash layer are in good agreement and range between ∼400 and 700 14C years (Table 2 [in original text]). Another soil 6.5 to 8.5 cm beneath the ash yields an age of 1,190+/-70 14CyearsB.P., which-considering its stratigraphic position-is consistent with the other seven. Two additional ages, however, are considerably older (1,130+/-60 14C years B.P. on top of the Martin coulees; and 1,980+/-70 14C years B.P. on top of a Mageik lava), and shed some doubt on those young ages. Although rootlet contamination (in spite of careful sample preparation) could contribute toward the youngest soil dates, slow soil development or erosion of the uppermost soil layer prior to tephra deposition might result in soil ages that are much older than the overlying ash layers. The number of (seemingly good) younger dates favors an age for the upper grey ash of ∼700 14C years. However, because the entire soil section on top of the Martin coulees (K-2661) yielded organic-rich samples free of any modern rootlets, one cannot rule out that∼1,100 14C years B.P. is a better record of the age of this tephra.\"","StartYear":1380,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":80,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Ugashik-Peulik","ParentVolcano":"Ugashik-Peulik","VolcanoID":"ak295","ParentVolcanoID":"ak295"},{"ID":3831,"Name":"Redoubt 450 yBP","Description":"From Beget and Nye (1994): \"A prehistoric pyroclastic flow deposit is exposed between two horizons of till in a stream cut through moraines just west of the piedmont lobe of the Drift Glacier (Fig. 1 [in original text]). The 1-2-m- thick flow rode up a steep, 10-m-high slope cut on the older moraine, and is truncated and buried by a younger moraine. These are the innermost moraines of the Drift Glacier, lying only a few hundred meters beyond its current border. They were probably deposited during the Little Ice Age of the 16th-19th century, so that the intercalated pyroclastic flow is also probably only a few hundred years old.\"","StartYear":1500,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1800,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Redoubt","ParentVolcano":"Redoubt","VolcanoID":"ak231","ParentVolcanoID":"ak231"},{"ID":3851,"Name":"Peulik Upper Grey Ash","Description":"From Fierstein (2007): \"The  youngest  of  the  19  ash  layers (K-2500N), 19 cm beneath intact 1912 fallout, rests on dark brown organic-rich fine soil dated at 450+/-65 14C year B.P. (Table 2 [in original text]; K-2500Ns). At this location it is a sharply defined 3.5-cm-thick couplet of two sublayers that correlate with the upper grey ash previously described. The couplet probably reflects two pulses of a single eruption, with the finest ash settling between explosive events. As detailed above, this ash may have originated at Mount Peulik, 75 km SW.\"","StartYear":1500,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":65,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Peulik","ParentVolcano":"Ugashik-Peulik","VolcanoID":"ak212","ParentVolcanoID":"ak295"},{"ID":3751,"Name":"Redoubt 400 yBP","Description":"From Beget and others (1994): \"A lower tephra, found from 30 to 50 cm depth, appears to record another, slightly older eruption of Redoubt Volcano. The EMP data show that this tephra is virtually identical to the Redoubt ash which occurs immediately above it (and about 50 years after it) in the Skilak Lake core sequence. This previously unknown Redoubt Volcano tephra eruption is estimated from sedimentation rate data to have occurred about 400+/-50 years ago.\"\r\n\"Recent field studies at Redoubt Volcano have identified a number of prehistoric lahars and intercalated weak soils preserved in the Rust Slough near the Drift River which were deposited approximately 250 14C yr B.P., corresponding to a calibrated calendar age of ca. 350 years ago (Beget and Nye, 1994). The similarity in age between the pair of Redoubt tephras found in Skilak Lake and the Rust Slough lahars suggests that the newly discovered tephras in Skilak Lake and the prehistoric lahars in the Rust Slough are broadly coeval, and apparently record a series of eruptions of Redoubt Volcano which occurred sometime between 300 and 400 years ago.\"\r\n*Note that the Rust Slough lahar has been given a separate prehistoric eruption entry in the database because the coeval relationship between the tephras and the Rust Slough lahar is suggested to be broadly coeval and the relationship between the tephras and the Rust Slough lahar is not well defined.","StartYear":1500,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":50,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Redoubt","ParentVolcano":"Redoubt","VolcanoID":"ak231","ParentVolcanoID":"ak231"},{"ID":1281,"Name":"Aniakchak New Cone Tephra","Description":"From Bacon and others (2014): \"On the east-southeast flank of Vent Mountain, New Cone was the source of lava that preceded much of that from Vent Mountain itself. Three radiocarbon dates on material associated with tephra thought to have a New Cone source (table 2 [in original text]) have a weighted mean age of 400+/-30 yr B.P. (table 1 [in original text]), though only the 390+/-60 yr B.P. date is from within the caldera. Tephra considered to predate New Cone is as young as Half Cone upper light pumice.\"","StartYear":1550,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":30,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":1761,"Name":"Aniakchak Cobweb Lava Flow","Description":"From Bacon and others (2014): \"Half Cone is the crescentic remnant of an andesite-dacite composite edifice that abuts the northwest caldera wall, its unsupported southeast half having been destroyed during explosive eruptions late in this volcano's life (fig. 13A [in original text]). The most recently active feeding conduit of Half Cone is marked by the center of the radially symmetrical Cobweb dacite flow (fig. 13B [in original text]).\"\r\n\"The final product of the Half Cone vent was crystal-rich dacite (~65-66 weight percent SiO2) that spread radially to form the Cobweb lava flow (figs. 13A and B [in original text]), now heavily mantled with tephra of the 1931 eruption. The flow has arcuate pressure ridges that are approximately concentric about a low central cratered cone above the vent, which is located somewhat west of center of the 1.5 km (north-south) by 2 km (east-west) lava field (fig. 10A [in original text]). At least six rifts traverse the flow surface from the center to the edges like spokes of a wheel. The longest of these appears to have channeled late-erupted lava northeast all the way to the margin of the flow field. Late-moving lava also emerges as short toes from the north and south margins of the field. The lava terminates on the northwest near the base of the Half Cone cliff. We adopt the name Cobweb for this lava flow after B.R. Hubbard (1932), who called it the \"Avernian Cobweb.\" \"The poisonous vapors of Avernus, Italy, killed many birds, and Hubbard witnessed the same at Aniakchak, which seems why he adopted this name\" (W. Hildreth, written commun., 2014).\"","StartYear":1550,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1931,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":1771,"Name":"Aniakchak Blocky Cone","Description":"From Bacon and others (2014): \"The well-preserved, 60-m-high cinder cone with ~20-m-deep crater near the southwest caldera wall opposite Birthday Pass is informally known as Blocky Cone (figs. 12Dand 14 [in original text]). Although Blocky Cone is mantled by lithic debris from the nearby 1931 vent, fresh basaltic andesite scoria is exposed on the southeast flank of the cone. This is some of the most mafic postcaldera magma (52.2-52.5 weight percent SiO2), comparable only to products of Breezy Cone. Blocky Cone appears to be younger than the Half Cone Pink and Brown Pumice (fig. 5C [in original text]) and to overlie older lava of Vent Mountain. Blocky Cone tephra has not been reported to be on the surface of the youngest Vent Mountain lava that nearly reaches the cone's eastern base, which suggests that this late-erupted Vent Mountain lava is younger than Blocky Cone.\"\r\nNeal and others (2001) classify the eruption of Blocky Cone as strombolian.","StartYear":1550,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1931,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":1781,"Name":"Aniakchak Vent Mountain lava and tephra","Description":"From Bacon and others (2014): \"Vent Mountain scoria and spatter cone is the most prominent topographic feature within the caldera (figs. 10, 12Cand 12D [in original text]). The cone rises 440-530 m above the caldera floor to an elevation of 3,350 ft (1,021 m). The 210-m-deep summit crater has a diameter of ~800 m. Numerous blocky lava flows emanate from the cone's lower flanks and from a prominent fissure vent that cuts the southwest flank. Although some outcrops of basaltic andesite and mafic andesite lava west of The Gates and in the larger maar crater possibly had source vents now hidden beneath Vent Mountain, the majority of products attributed to that volcano are silicic andesite and dacite.\"\r\n\"The youngest Vent Mountain lavas emanate from the south fissure vents, draping the south flank between lobes of earlier lava and spreading out from the southwest and south bases of the Vent Mountain edifice to pond against the caldera wall. One of these flows incised a channel into a small glacier and descended to the northeast through New Cone crater to overlap earlier Vent Mountain lava. Tephra from multiple eruptions at the summit, the south fissure, and New Cone blankets the west, south, and east flanks of the Vent Mountain edifice. The youngest products of Vent Mountain are agglutinated spatter plastered on the north side of the cone and a small lava dome in the summit crater. The total volume of Vent Mountain lava and tephra probably exceeds 1.5 km. If the radiocarbon constraint on New Cone is correct, much of Vent Mountain lava was erupted since ca. 400 yr B.P. The youngest flows and agglutinate predate only the 1931 eruption.\"\r\nFrom Neal and others (2001): \"Two young,  but prehistoric, explosive events at Aniakchak occurred closely spaced in time about 400 years BP. The first is inferred to have originated from the flank of Vent Mountain, a prominent intracaldera cone  (cover  photo;  fig. 5 [in original text]).  This eruption dispersed energetic pyroclastic surges within the caldera and fallout to the north and northeast of Aniakchak.\"","StartYear":1550,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1931,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":3771,"Name":"Redoubt Rust Slough Lahar and tephra","Description":"From Beget and Nye (1994): \"An assemblage of young flood deposits and a slightly older lahar are exposed in stream cuts along Rust Slough, only a few kilometers to the southwest of the Drift River Terminal (Fig. 11 [in original text]). The basal lahar in this assemblage was exposed just at the 1990 water level along Rust Slough, is commonly yellow to red, and is referred to here as the Rust Slough lahar. It consists primarily of highly oxidized and altered lithic clasts in a clayey matrix of hydrothermally altered material and is 2-3 m in thickness (Fig. 12 [in original text]). The abundance of hydrothermally altered material suggests that this deposit records a partial collapse of part of a prehistoric summit edifice of Redoubt Volcano. The reddish color of the waters in Rust Slough may in part reflect the leaching of iron oxides and the erosion of yellow and reddish clays from stream cuts through this deposit. This thick lahar is exposed for several kilometers along upper Rust Slough, but probably underlies a much larger area of the Drift River fan where it has been buried by younger deposits.\"\r\n\"A 2-4-cm-thick peat horizon buried by the Rust Slough lahar was dated at 1060+/-70 yr B.P. (Table 1 [in original text]). The peat overlies thinly bedded alluvium that is locally as much as 2 m thick, and extends below the current level of Rust Slough. The yellow lahar itself is overlain by as much as 2 m of alluvium that has buried a thin soil and peat horizon developed on the surface of the Rust Slough lahar. Tree stumps as much as 30 cm in diameter are preserved in growth position above the yellow lahar; one stump was dated at 260+/-60 yr B.P. and provides an upper limiting date on the underlying yellow lahar. A concordant upper limiting date was obtained from a similar site in the upper Drift River valley (see below).\"\r\n\"There are isolated and rounded pumice lapilli in the lake- sediment section, but no deposits of airfall tephra layers or pyroclastic flows, which suggests they formed during a dormant interval at Redoubt Volcano. The apparent existence of a Drift Glacier dam of the upper Drift River valley also suggests a period without major eruptions. The 1966 eruptions largely destroyed the upper parts of the Drift Glacier, and produced a prolonged period of stagnation that stopped an advance that might have dammed the upper Drift River. The Drift Glacier had largely reformed by the late 1980s and was advancing again (Sturm and others, 1986), but the 1989-1991 eruptions again removed its upper parts. Similar destruction of the glacier by eruptions almost certainly did not occur during this prehistoric interval when it was large enough to dam the upper valley.\"\r\n\"The lake sediments are overlain by a ca. 1-m- thick, clay-rich yellow lahar, and a similar deposit of yellow, hydrothermally altered clayey debris is locally exposed in stream cuts for more than hundred meters along the Drift River downstream from the lacustrine section. This distinctive yellow lahar is thought to be correlative with the thick yellow lahar found at Rust Slough. Both overlie non-volcanic deposits, as the upper lahar rests upon the lacustrine sequence, while the clayey lahar at Rust Slough overlies thinly bedded alluvium. In addition, a thin soil above the yellow lahar at the lake sediment section was dated to 210+/-50 yr B.P., close to the date of 250+/-60 yr B.P. on wood from above the clayey yellow lahar at Rust Slough (Fig. 12 [in original text]). The very weak soil development on this deposit suggests it is not much older than the radiocarbon dated soil, so that this widespread clay-rich lahar appears to record a massive slope failure of hydrothermally altered debris from the north side of Redoubt at ca. 200-400 yr B.P.\"\r\n\"The presence of the Rust Slough lahar near the Drift River Terminal more than 30 km downvalley from Mount Redoubt indicates this deposit was originally quite extensive. We cannot directly reconstruct its areal extent and volume, as the Rust Slough lahar has been largely buried by younger lahars and flood deposits. However, if a distribution similar to the flood deposits of the 1989-1990 eruption is assumed, its original volume may have been on the order of 100-200 X 106 m 3. For comparison, the volume of the Crescent River lahars has been estimated at 435 X 106 m 3 (Riehle and others, 1981). The modern summit basin, partly exposed by melting of the upper Drift Glacier during the 1989-1990 eruptions, is about 200-250 m deep, open to the north, and has a volume of about 100 X 10 6 m 3. Perhaps this crater reflects a massive slope failure several hundred years ago that produced the Rust Slough lahar.\"\r\nFrom Beget and others (1994): \"Recent field studies at Redoubt Volcano have identified a number of prehistoric lahars and intercalated weak soils preserved in the Rust Slough near the Drift River which were deposited approximately 250 14C yr B.P., corresponding to a calibrated calendar age of ca. 350 years ago (Beget and Nye, 1994). The similarity in age between the pair of Redoubt tephras found in Skilak Lake and the Rust Slough lahars suggests that the newly discovered tephras in Skilak Lake and the prehistoric lahars in the Rust Slough are broadly coeval, and apparently record a series of eruptions of Redoubt Volcano which occurred sometime between 300 and 400 years ago.\"\r\nFrom Beget and others (1994): \"The next lower tephra occurs at a depth of 24-40 cm, depending on local core sedimentation rates (Fig. 2 [in original text]). At core sites with low sedimentation rates this tephra lies close to or is even mixed with the overlying Crater Peak ash discussed above. This tephra is geochemically quite similar to the tephra erupted in 1989-1990 and 1902 at Redoubt Volcano, and appears to record a previously unknown Redoubt eruption at ca. 350+/-50 years ago, based on sedimentation rate extrapolations.\"","StartYear":1550,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1750,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Redoubt","ParentVolcano":"Redoubt","VolcanoID":"ak231","ParentVolcanoID":"ak231"},{"ID":2121,"Name":"Augustine Tephra B","Description":"From Beget and others (1994): \"The next lower tephra occurs from 22 to 64 cm below the top of cores, depending on localized sedimentation rates, and is correlated here with tephra layer \"B\" from Mount St. Augustine in the southernmost part of Cook Inlet. Field studies at Mount St. Augustine (Siebert and others, 1989) showed that the West Island debris avalanche occurred about 367+/-55 yr B.P., and Beget (1989) showed that the 30-50-cm-thick pumiceous air-fall layer B tephra on Augustine Island was erupted at about the same time [note that more recently, Waitt and Beget (1996) indicate that the West Island debris avalanche occurred after tephra layer B, thus the West Island debris avalanche has been entered in to the database separately]. Conversion of the age of layer \"B\" and the West Island debris avalanche to calendar years using the approach of Stuiver and Becker (1986) yields a calibrated age of about 1490 A.D., indicating these eruptions occurred ca. 500 years ago. The discovery of Layer \"B\" from Mount St. Augustine at Skilak Lake demonstrates that this prehistoric tephra was distributed at least 200 km north of the source volcano, and provides an important chronologic datum, allowing estimates of the age of younger tephras in the Skilak Lake cores by interpolation and sedimentation rate estimates.\"\r\nFrom Waitt and Beget (2009): \"Of the two youngest coarse tephras, M drifted south and B strongly northeast (fig. 7 [in original text]).\"\r\n\"On the south and west, tephra M seems everywhere much thicker than tephra B.\"\r\n\"The two major Augustine proximal tephras that are also identified in distal locations are tephra B (about 390 yr B.P.) and tephra I (about 1,700 yr B.P.). Tephra I is about 3 cm thick at a distance of 110 km, and B is about 7 mm thick at a distance of 200 km (fig. 8 [in original text]).\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; accessed 2017) reports a magnitude of 4, bulk eruptive volume of 0.100 cubic km and a dense rock equivalent eruptive volume of 0.040 cubic km for the eruption.","StartYear":1560,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":1291,"Name":"Aniakchak Half Cone Pink and Brown Pumice","Description":"From Bacon and others (2014): \"Half Cone is the crescentic remnant of an andesite-dacite composite edifice that abuts the northwest caldera wall, its unsupported southeast half having been destroyed during explosive eruptions late in this volcano's life (fig. 13A [in original text]).\"\r\n\"In the north wall of Half Cone, coarse poorly sorted pumice fall layers form wedges tapering away from both sides of the truncated, crater-filling dome (fig. 13C [in original text]). Beds of the lowest approximately one-third of the western wedge, which are rich in coarse, relatively dark dense clasts, are crosscut by lighter colored pumiceous beds of the middle third. A small remnant of a lava dome rests on the latter beds and is overlain by the uppermost third of the wedge beds, which are intermediate in color. These deposits are overlain by the ca. 400 yr B.P. Pink Pumice fall sequence (see next section [in original text]). Thick exposures of lava in the west wall are compositionally identical to the crater-filling dome and may be equivalent. Xenoliths of distinctive white felsite are common in these dacite lavas. The northeasternmost lava in the Half Cone wall, thick dacite that has prominent vitrophyre columns above its base, is likely correlative with the crater-filling dome judging from its proximity and similar appearance. The western near-vent fall-deposit wedge of Half Cone lies on silicic andesite (63 weight percent SiO2) lava of unique composition known only from that locality. Subhorizontal vitrophyre columns ~6-10 cm across, perpendicular to a caldera-facing vertical joint surface that strikes east-northeast, suggest that this lava may have effused from a buried vent near the northwest caldera wall and encountered ice or deep snow in the caldera before the eruption of Half Cone.\"\r\n\"A series of Plinian eruptions ca. 400 yr B.P. produced widespread pumice falls and destroyed much of the original Half Cone edifice (Neal and others, 2001; Browne, 2006). Pyroclastic flows and surges affected much of the caldera floor. Canyons to the east of Half Cone expose more than 40 m of pyroclastic-flow deposits related to this event. Outside the caldera, the pumice fall is 10 cm thick at least 50 km to the north. Fine ash may extend as far as 330 km (Riehle and others, 1999). Total erupted volume is estimated at 0.75 to 1.0 km3 (Neal and others, 2001). The areally extensive units are two volumetrically subequal, successive Plinian fall deposits known by the informal unit names of the Pink Pumice (fig. 13F [in original text]) and the overlying Brown Pumice; the contact between Pink and Brown Pumice falls is gradational through a modest thickness. The dacitic Pink Pumice (63-67 weight percent SiO2) is highly vesicular and carries few phenocrysts. Two horizons within the Pink Pumice deposit have relatively coarse pumice and lithic clasts. The normally graded Brown Pumice layer consists of relatively crystal-rich andesite pumice (58-62 weight percent SiO2). White felsite (77 weight percent SiO2), granitic, and crystal tuff xenoliths are common in the fall deposits. Five radiocarbon dates are for materials associated with the Pink Pumice (table 2 [in original text]). We consider the weighted mean of 380+/-50 yr B.P. (table 1 [in original text]) for the two youngest dates, which are for wood and for which stratigraphic context is clear, to provide the most accurate constraint on the Pink Pumice eruption.\"\r\nFrom Neal and others (2001): \"The...eruption occurred at Half Cone, at the base of the northwest caldera wall (fig. 5 [in original text]), and was one of the most violent events in recent history at Aniakchak. An estimated 0.75 to 1.0 km 3 of material (about the size of the May 18, 1980, eruption of Mount St. Helens, excluding the debris avalanche) destroyed a preexisting edifice at Half Cone and inundated most of the caldera floor with pyroclastic flows, surges, and fallout many meters thick. Near the vent, these deposits are more than 40 m thick. A 10-cm accumulation of pumiceous lapilli and coarse ash from this eruption can be found at least 50 km to the north, at the surface or just below the modern root mat, and fine ash may extend as far as 330 km (Riehle and others, 1999). During the final phase of this eruption, a lava flow filled the basin formed during the collapse of Half Cone.\"\r\nThe Global database on large magnitude explosive volcanic eruptions (LaMEVE; 2016) reports a magnitude of 4.9, bulk eruptive volume of 0.875 cubic km and a dense rock equivalent eruptive volume of 0.150 cubic km for the eruption.","StartYear":1570,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":50,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":3981,"Name":"Aniakchak Post Pink and Brown Pumice Tephrafall","Description":"From Bacon and others (2014): \"Atop the Pink and Brown Pumice layers on Half Cone itself are several more light and dark colored fall beds that have a total thickness of ~60 m. These vary from nonwelded pink-to-buff pumice fall to brick-red oxidized lithic-rich fall breccia and dark gray welded agglutinate. The variations in lithic content and welding are due to changes in eruption intensity at the vent. Although these layers have not been studied in detail, their thicknesses decrease substantially over short distances from Half Cone. Outcrops of this agglutinate are found as short, low ridge segments near the surface on the caldera floor northeast of Half Cone, as patches on Vent Mountain and West Dome, and in the wall of the 1931 Main carter. They are cut by the cliff face of Half Cone and are overlain by deposits of the 1931 eruption.\"","StartYear":1570,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":50,"StartQualifierUnit":"Years","EndYear":1931,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":2591,"Name":"Iskut-Unuk River cones Lava Fork Lavas","Description":"From Stasiuk and Russell (1990): \"The Lava Fork lavas are the youngest volcanic rocks of the Iskut River region and may represent the youngest volcanic eruptions in Canada (Elliott and others, 1981 ; Souther, in pressa). Age dates for the Lava Fork lavas (14C) are as young as 360+/-60 years BP (Souther, in press a). The Lava Fork volcanic rocks are spectacularly exposed and the lava field displays a wide variety of volcanological features including lava tubes and spatter vents.\"\r\n\"The main lava flow appears to have erupted from a vent located on a ridge of crystalline basement rocks at an elevation of 1400 m. The vent area is delimited by a thick blanket of black, glassy pyroclastic tephra which mantles bedrock and glaciers to the north, east and south.\"\r\n\"The main lava flows appear to have been erupted in a single period and were probably fed by lava fountains; the top surfaces of the lavas are occasionally covered with spatter agglutinate. The lava fountaining filled the cone with ponded lava, which eventually broke out, flowed across the ridge top, over a knob-like shoulder and down the steep valley wall to flood the valley floor below. This interpretation implies that the spatter bombs on the flanks of the cinder cone are part of the same eruptive activity that produced the lava flows.\"\r\n\"The main lava flow lies within the Lava Fork valley and, by damming the Lava Fork Creek, formed the two Lava Lakes. The southern limb of the lava flow extends south along the valley bottom for at least 20 krn into Alaska. Generally, the flow surface is scoriaceous and may have a thin veneer of clinkery material. Pahoehoe, ropy surfaces are common, and in places the lava flow has developed numerous, prominent lava channels with prominent levees (north fork of the lava at about 1040 m). The lava rivers commonly develop into lava tubes which subsequently have collapsed. In several localities, the lava tubes remain intact and are as high as 3 m and extend for 30-40 m.\"\r\nFrom Hauksdottir and others (1994): “14C dating of a partly charred conifer log from the surface of one of the flows yielded an age of 360+/-60 BP (Table 1 [in original text], Elliott and others, 1981). Grove (1986) argued for an age of 130 BP based on 14c dating of material associated with the lower flows...Based on tree ring counts on living trees, and observations of the lava flow surface it is estimated to be around 150 years old. Living trees on the surface of an underlying flow give a minimum age of 350 years (B.C. Hydro, 1985).\"\r\n\"A possible vent for the older flows is a tree-covered cinder cone located 4 km downstream of Blue Lake (B.C. Hydro, 1985).\"","StartYear":1590,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":60,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iskut-Unuk volcanic field","ParentVolcano":"Iskut-Unuk volcanic field","VolcanoID":"ak136","ParentVolcanoID":"ak136"},{"ID":2131,"Name":"Augustine Young Domes","Description":"From Waitt and Beget (1996): \"Two domes of porphyritic gray andesite form conspicuous topographic bumps at altitudes 1025 and 910 m on the upper northwest flank, some 400 to 800 m northwest of the central summit-dome complex. The large West lsland debris avalanche (table 3 [in origincal text]) must have left a large crater including this area so the domes must be younger than about 350 yr B.P. (age of B tephra, table 2 [in original text]), though they precede the historic eruptions.\"","StartYear":1650,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1812,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":2141,"Name":"Augustine Grouse Point Debris Avalanche","Description":"From Waitt and Beget (1996): \"Between about 350 yr B.P. (after tephra layer B) and historic time, three separate debris avalanches swept to the sea on the west-northwest, north-northwest, and northflanks. One of them (West Island} was large and fast, most of it having rode to sea beyond a sea cliff cut back into older deposits.\"\r\n\"Grouse Point diamict is hummocky with local relief of 5 m and is composed of reddish porphyritic andesite including anfular boulders at least as large as 2.5 m. Overlying stratigraphy in upward stratigraphic succession is lithic pyroclastic-flow deposit, possibly waterlaid (tsunami?) deposit, two thin ash layers, and the distinctive white Katmai 1912 ash.\"\r\n\"At lowest tides a nearly continuous field of boulders extends nearly a kilometer seaward of the present beach. The deposit has been eroded back into a nearly continuous, sharply curving sea cliff 4-7 m high. Thus geomorphically this deposit seems older than the similarly coarse and hummocky West Island and Rocky Point deposits but much younger than the South Point diamict and others on the south and east coasts. It may be an eastern arm of Lagoon debris-avalanche deposits.\"\r\n\"Grouse Point debris-avalanche deospit covers part of the sea cliff cut into North Bench deposit. By this and its far more hummocky surface texture, Grouse Point diamict is geomorphically distinct from North Bench diamict. Also contrasting the arrested sea cliff of Borth Bench, Grouse Point deposit juts into the sea. Grouse Point deposit must be considerably younger than North Bench diamict.\"\r\n\"Grouse Point diamict is not proven to predate the B tephra, exposed in gullies upslope from North Bench diamict 8unit IMan). Beget and Kienle (1992) having not distinguished North Bench diamict from Grouse Point diamict, they inferred the Grouse Point as well as North Bench diamict to underlie the B tephra.\"\r\n\"During this prehistoric period numerous domes must have been emplaced at the summit, repeatedly renewing the source for catastrophic debris avalanches. Remnants of these older domes form the east and south sides of the present summit-dome complex. Below the summit area at least three domes were emplaced on the upper flanks, one on the south (Karnishak dome), two on the northwest (domes \"I\" and \"H\"). Another undated and nearly buried dome or lava flow diversifies the upper south flank.\"","StartYear":1650,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1812,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":2151,"Name":"Augustine Prehistoric Lava Flow","Description":"From Waitt and Beget (1996): \"Between about 350 yr B.P. (after tephra layer B) and historic time... Augustine's only conspicuous lava flow was emplaced on the north flank.\"\r\n\"A conspicuous lava flow on the middle north flank consists of massive porphyritic andesite ranging from light gray to oxidized light reddish brown. It contains about 10 percent plagioclase phenocrysts as large as 4 mm. The apex of the conspicuous landform at about altitude 650 m apparently marks the site of a flank vent, about 600 m below the present summit, indeed below the base of the entire summit-dome complex. The flow terminated 450 m below its apex at a distance of 1.75 km.\"\r\n\"This lava flow is usually considered as the last part of the 1883 eruption (Kienle and Forbes, 1976; Siebert and others, 1987, 1989, 1995; Swanson and Kienle, 1988). Kienle and Swanson (1980) had called it \"prehistoric\" but gave no evidence. Overlying the upper east side of the lava flow is a sharp-crested ridge at least 640 m long and as thick as 15 m consisting of diamict including many angular fragments as large as 5 m of dome-rock porphyritic andesite. In any one small area of this deposit the andesite boulders are diversely black, reddish, and gray. This clearly mixed deposit is a debris-avalanche levee. The debris can be traced downslope to altitude 450 m, below which it is discontinuous but aligned with a sharp levee well defined below altitude 200m, the west edge of the Burr Point debris-avalanche deposite (see below [in original text]). The Burr Point debris avalanche occurred at or near the beginning of the 1886 eruption: the lava flow is older. The lava flow appears to be overlain by just one coarse diamict, and thus it must be younger than the Rocky Point debris avalanche, which would have swept down the lava flow had it then existed...The stratigraphy level beneath the Burr Point diamict and its position on the north flank suggest that the lava flow occurred late during an eruption that began with the Rocky Point debris avalanche.\"\r\n\"A hypothetical alternative for its age is that North Slope lava flow began the 1883 eruption and was later overridden by the Burr Point debris avalanche. Problems with such a model include: (a) there is no evident baking of the base of the overlying debris avalanche as might have occurred had the lava been fresh and hot, and (b) a vent at mid-altitude on the flank should have provided the outlet for magma and relieved vent pressure, precluding injection of magma higher that would cause a debris avalanche later in the eruption.\"","StartYear":1650,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1812,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":2161,"Name":"Augustine Rocky Point Debris Avalanche","Description":"From Waitt and Beget (1996): \"Between about 350 yr B.P. (after tephra layer B) and historic time, three separate debris avalanches swept to the sea on the west-northwest, north-northwest, and northflanks. One of them (West Island} was large and fast, most of it having rode to sea beyond a sea cliff cut back into older deposits.\"\r\n\"West of Burr Point, a diamict forms a sharp point of land (Rocky Point). The deposit has a sharply hummocky topography with a relief of 40 m and local slopes as steep as 35 degrees and comprises angular andesite boulders at least as large as 5 m. At low tide this debris forms bouldery islands (unit ob) as far as 1.5 km offshore that have been winnowed and beveled to bouldery shoals.\"\r\n\"Capping the coarse diamict in upward succession is weakly oxidized soil horizon 20 cm thick, an organic layer, a gray silt ash (1883 eruption?), and a distinctive white silt ash from the 1912 Katmai eruption. The irregular, curving sea-cliff line is roughly similar to that at West Island. The sharp morphology of the hummocks and that it has but one ash layer beneath the Katmai ash makes this deposit is both geomorphically and stratigraphically younger than the West Island debris-avalanche deposit.\"\r\n\"During this prehistoric period numerous domes must have been emplaced at the summit, repeatedly renewing the source for catastrophic debris avalanches. Remnants of these older domes form the east and south sides of the present summit-dome complex. Below the summit area at least three domes were emplaced on the upper flanks, one on the south (Karnishak dome), two on the northwest (domes \"I\" and \"H\"). Another undated and nearly buried dome or lava flow diversifies the upper south flank.\"","StartYear":1650,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1812,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":2171,"Name":"Augustine West Island Debris Avalanche","Description":"From Waitt and Beget (1996): \"Between about 350 yr B.P. (after tephra layer B) and historic time, three separate debris avalanches swept to the sea on the west-northwest, north-northwest, and northflanks. One of them (West Island} was large and fast, most of it having rode to sea beyond a sea cliff cut back into older deposits.\"\r\n\"A diamict of brecciated andesite-dacite forms West Island, separated from the northwest coast of Augustine Island by Northwest lagoon 0.5 km wide. The deposit is a mixture of angular to very angular reddish to grayish porphyritic andesite boulders as large as 4 m set in a nonsorted matrix of finer diamict. The West Island deposit comprises a central core of unmodified high conical hummocks as high as 30 m with slopes as steep as 40 degrees, surrounded on seaward sides by a wide zone of lower hummocks (all unit Bawa). The hummocks are capped by 0-30 cm of humus and five sand ashes of which three underlie the Katmai 1912 white-silt ash. The B tephra is absent from West Island and thus the hummocky diamict must predate 350 yr B.P. (table 2 [in original text]). In a gully 1.2 km back from the lagoon at altitude 85 m, a landward phase of the deposit (unit Bawi)is underlain by the (M?) tephra (but B tephra is missing.\"\r\n\"On the seaward side there is but a discontinuous sea cliff cut into sporadic hummocks, though the irregular cliff line is fairly straight. West Island deposit is thickly vegetated by shrub alder and a few spruce. A continuous filed of boulders ranging up to 5 m in diameter extends at least as far as 1.3 km offshore, much of it visible at the lowest spring tides and discernable as well on aerial photographs.\"\r\n\"Hummocks on the southwest side of West Island are nearly flat topped, apparently beveled down as much as 20 m. These southwestern hummocks are also sharply incised, and some of them capped by coarse winnowed lag of openwork boulders as large as 4 m. A few of them are overlain by poorly sorted sand, perhaps waterlaid, as high as 5 m above high-tide level. The geomorphically modified southwestmost hummocks are evidence of a great ruch of water across them. This evidence of a huge flow of water perhaps records a great sea wave (tsunami) created as West Island debris avalanche plowerd into the sea with high momentum. The modification could not have been caused by an 1883 tsunami originating from Burr Point because the low-level hummocky the north part of West Island (facing Burr Point) is unmodified and because at least one of the modified hummocks is overlain by tephra older than the 1912 Katmai ash.\"\r\n\"During this prehistoric period numerous domes must have been emplaced at the summit, repeatedly renewing the source for catastrophic debris avalanches. Remnants of these older domes form the east and south sides of the present summit-dome complex. Below the summit area at least three domes were emplaced on the upper flanks, one on the south (Karnishak dome), two on the northwest (domes \"I\" and 'H\"). Another undated and nearly buried dome or lava flow diversifies the upper south flank.\"","StartYear":1650,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1812,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":2191,"Name":"Mt Churchill Lena Tephra","Description":"From Payne and others (2008): \"The internal comparisons suggest correlation among ECR 32, LNA 39, and SPM 26 layers. All of these tephras show strong similarity to the White River Ash (WRA). SCs are as great as 0.99 with proximal WRA deposits and 0.96 with distal deposits (Table 4 [in original text]).\"\r\n\"The CHP 33 tephra has been directly radiocarbon dated. A sample of Sphagnum leaves gave an age estimate of 280-320 cal yr BP (Table 6 [in original text]) and a sample of Sphagnum stems gave a marginally less precise date with a calibrated age range of 290-460 cal yr BP, supporting the choice of Sphagnum leaves for the other dates. The CHP 33 tephra was therefore deposited around 300 cal yr BP. Although the CHP 33 tephra does not have EPMA data, the balance of probability suggests that a single tephra layer was deposited at all five sites around 300 cal yr BP, or approximately AD 1650.\"\r\n\"All of the sites contain a tephra layer dating to ca. 300 cal yr BP (AD 1650) with a major element geochemistry similar to that of the White River Ash. Both the eastern and northern lobe WRA deposits are considerably older, around 1147 and 1890 cal yr BP, respectively (Lerbekmo and others, 1975; Clague and others, 1995). Accumulation rates of ombrotrophic mires are usually in the range 10-20 yr cm. Robinson and Moore (1999) reported the depth of the WRA tephra in western Canadian peatlands; in ombrotrophic sites, the mean depth of the tephra was 68 cm whereas in poor fens it was 54 cm. The sites in this study are farther south in a more climatically favourable location for peat accumulation. It is therefore extremely unlikely that a tephra at this depth could be a correlative of either of the WRA deposits. No younger eruptions are known from Mt. Churchill. The only volcano in the Wrangell Volcanic Field to have had historic-age eruptions is Mt. Wrangell. However, there are no known eruptions near the probable age of this tephra, and the high degree of geochemical similarity to the WRA means a different source is improbable. The most likely source of the tephras is therefore a previously unknown eruption of Mt. Churchill, within the last 600 yr, and most probably around AD 1650. We propose the name ‘Lena tephra’ for this layer following the convention of naming previously unknown tephras after the site in which they were first located.\"\r\nFrom Preece and others (2014): \"...cores in southeastern Alaska contain two other tephra beds with compositions similar to WRA. These are the ca. 300 yr B.P. (ca. A.D. 1650) Lena ash preserved at sites A and B (Fig. 1 [in original text]) and the ca. 6330 cal yr B.P. MTR-146 ash preserved at site B (Fig. 1 [in original text]) (Payne and others, 2008).\"","StartYear":1650,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Churchill, Mt","ParentVolcano":"Churchill, Mt","VolcanoID":"ak50","ParentVolcanoID":"ak50"},{"ID":2501,"Name":"Iliamna Red River Lahar","Description":"From Waythomas and others (2000): \"The Red River Valley, including Red Glacier, was a primary flow path for lahars of Holocene age and is an area that is highly susceptible to inundation by future lahars from Iliamna Volcano (Fig. 14 [in original text]). Lahar deposits were discovered at three locations (RR-1, RR-2, and RR-3, Fig. 14 [in original text]) and large stranded blocks of andesite, delivered to this area by lahars, are common on the alluvial fan of Red River and along the beach near exposure RR-3 (Fig. 14 [in original text]).\"\r\n\"Exposure RR-3 is a several-kilometer-long sea bluff located along the Cook Inlet coastline, just north of the mouth of Red River (Fig. 14 [in original text]). A single noncohesive lahar deposit is present at this location (Fig. 17 [in original text]). The lahar deposit is massive, matrix-supported, and contains mostly cobble to boulder-size clasts of andesite and minor amounts of sand-stone. About 15 percent of the clasts in the deposit are angular, 30 percent are subangular, 31 percent are subrounded, and 24 percent are rounded (n=100; Fig. 17 [in original text]). The lahar deposit is normally graded and exhibits intense red-orange oxidation zones (Fig. 17B [in original text]) and oxidation halos around fragile prismatically jointed juvenile andesite clasts. The prismatically jointed clasts indicate that fragments of the erupted magma cooled and contracted after the lahar came to rest (Francis, 1993, p. 252) and in combination with burned wood in the deposit indicate that the lahar was probably still hot when it reached Cook Inlet. The texture of the distal part of the lahar is distinctly finer grained and slightly better sorted (relative to proximal parts of the deposit) indicating that the lahar may have begun transforming to hyperconcentrated flow when the lahar reached the coast (Fig. 17C [in original text]).\"\r\n\"Charred wood fragments, logs, and charcoal from the lahar deposit at RR-3 gave radiocarbon ages of 200+/-300 yr BP and the oldest spruce trees growing on the bluff top are about 280 yr old as determined by tree coring (Beget, 1996 and unpublished data). Thus the lahar and associated eruption must have occurred by at least 300 yr BP. The lahar deposits at RR-1, RR-2, and RR-3 are texturally and compositionally similar and have equivalent stratigraphic positions. These deposits and the large andesite boulders in the Red River alluvial fan are the likely remenants [sic] of an extensive hot lahar initiated by a pyroclastic eruption of Iliamna Volcano about 300 yr BP.\"","StartYear":1650,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":3741,"Name":"Spurr 300 yBP","Description":"From Beget and others (1994): \"The next lower ash in the Skilak cores occurs at a depth of 16-26 cm, and is compositionally much more mafic than the majority of tephras found in the cores (Table 1 [in original text]). Crater Peak, a subsidiary vent of Mt. Spurr, was almost certainly the source of this andesitic tephra. During historic eruptions of Mt. Spurr in 1953 and in 1992, ash from Crater Peak was deposited in Anchorage and other areas around Cook Inlet. The Crater Peak vent is the only Cook Inlet volcano which produces such widely dispersed mafic tephras (Riehle, 1985; Nye, 1990). The ash in Skilak Lake therefore is thought to record a previously unknown eruption of Crater Peak at Mt. Spurr about 300+/-50 years ago, with the age estimate based upon sedimentation rate estimates and interpolation between the historic tephras at the top of the cores and the 500-year-old tephra layer B from Mount St. Augustine found lower in the cores (Fig. 7 [in original text]).\"","StartYear":1650,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":50,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Spurr","ParentVolcano":"Spurr","VolcanoID":"ak260","ParentVolcanoID":"ak260"},{"ID":3881,"Name":"Great Sitkin 280 yBP","Description":"From Waythomas and others (2003): \"Lahar deposits in Sitkin and Akuyan Creek valleys; Pyroclastic flow deposits in Glacier Creek valley; Pumice lapilli tephra deposits.\"","StartYear":1670,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":269,"Name":"Amak 1700","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) reports that between \"1700-1710 (?) volcanic activity on * * * Amak (beginning of the eighthteenth century).\"  Marsh (in Wood and Kienle, 1990) states that \"granular, blocky leveed flows have erupted in historic times.\"\r\nFrom Marsh and Leitz (1978): \"The younger series of flows issued from a central vent located slightly south of the initial crater. These lavas breached the initial summit crater on the south and, at least in part, flowed down pre-existing glacially-cut valleys. These flows are chaotic, and wholly comprised of large angular blocks ranging in size from 0.1 m to several meters. Most blocks show traces of having been sheared and granulated. The lava is dark gray with a porous and sugary texture. At the outer margin of the southern flank this series has an apparent thickness of about 100 m. Moss and lichen growth on these flows, confirm that two periods of eruption produced this younger series. A thin layer (1 cm) of volcanic ash caps some of the larger blocks; this ash is probably from nearby Shishaldin volcano on Unimak Island, which has been active intermittently for at least the last 200 years (Coats 1950).\"\r\n\"According to Funk (1973) the latest period of glaciation in this area was about 6,700 years B.P. The small U-shaped glacial valley cut into the older series was probably excavated during this period of glaciation. The older flows also show no sign of being extruded beneath ice. Thus Amak is probably not much older than 6,700 years. Early explorers (Dall 1897) reported volcanic activity on Amak during 1700-1710 and 1796 but report that by 1867 all activity had ceased. The younger series of flows was, surely, extruded during these times.\"","StartYear":1700,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1710,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Amak","ParentVolcano":"Amak","VolcanoID":"ak8","ParentVolcanoID":"ak8"},{"ID":413,"Name":"Iliamna 1741","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) writes that in 1741, Mt. Iliamna, or Bering's Mt. Dolmat, \"grew quiet.\"","StartYear":1741,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1741,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":4091,"Name":"Great Sitkin Forty Year Ash","Description":"From Kiriyanov and Miller (1997): \"AD-1 has a thickness of 6-10 cm and consists of a pinkish-gray clay- or silt-size material containing lenses of fine-grained volcanic sand. The main components are volcanic glass (69%) and plagioclase (21%). The characteristic features are a significant amount of pyroxenes (6%) and absence of green or brown hornblend (Fig. 5 [in original text]). More than 50 wt. % of the sample are particles smaller than 0.071 mm in size. The glass is colorless, juvenile, and contains microlites of plagioclase. The approximate carbon-14 age of the ash is less than 200 years (P. Black determined its carbon-14 age of 40 years, Table 1 [in original text]).\"","StartYear":1750,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":3731,"Name":"Okmok 400 yBP","Description":"From Beget and others (2005): \"There is evidence that a lake filled the caldera to a depth of 150 meters over a period of several hundred years. The caldera lake drained catastrophically after failure of part of the caldera rim. The resultant flood caused deep erosion of the landscape on the north side of the volcano (Wolfe, 2001). Lahar deposits are present at low elevations in many of the stream valleys draining the volcano, and can be traced up to 12 kilometers down valley from the caldera rim. At most sites only a single lahar deposit is exposed, but at least three lahars, each more than 1 meter thick, occur in sea cliffs near the mouth of Ginger Creek on the west flank of the volcano, and are exposed intermittently for more than 2 kilometers along the beach. Radiocarbon dates suggest these lahars were emplaced 300 to 400 years ago.\"","StartYear":1750,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1650,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Okmok","ParentVolcano":"Okmok","VolcanoID":"ak206","ParentVolcanoID":"ak206"},{"ID":17,"Name":"Gareloi 1760","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch), pg. 121, states Gareloi was active in 1760.  Page 122 states that Gareloi was smoking in 1760.","StartYear":1760,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Gareloi","ParentVolcano":"Gareloi","VolcanoID":"ak106","ParentVolcanoID":"ak106"},{"ID":61,"Name":"Kasatochi 1760","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) writes that in 1760, Koniuji island was rising.\r\nCoats (1950) attributes historical eruptions of Koniuji to Kasatochi instead, because Koniuji is \"deeply eroded\" and \"does not appear to have been active in Recent time.\"  Lending credence to this thought is Bergsland's  (1959, p. 35) publication which records the Aleut place name of Kasatochi as \"qana-tanar\" = which island, as in \"which island is it that is emerging out there.\"","StartYear":1760,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kasatochi","ParentVolcano":"Kasatochi","VolcanoID":"ak146","ParentVolcanoID":"ak146"},{"ID":158,"Name":"Great Sitkin 1760","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) reports that Tolstykh and Baikov reported Mt. Moffet active in 1760.  However, Mt. Moffet does not appear to have had any historical eruptions, and perhaps the eruption was from Great Sitkin instead (Hantke, 1951; Simkin and Siebert, 1994; Fournelle and others, 1994; and Waythomas and others, 2003).","StartYear":1760,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":395,"Name":"Wrangell 1760","Description":"   The 1760 and 1784 eruptions of Wrangell are questionable, poorly documented, and may in fact refer to a volcano other than Mt. Wrangell.  Dall (1870) says that \"Chechitno\" smoked in 1760, and again in July 1784.\r\n   These eruptions are first reported by  Grewingk (1850, translated 2003 by Fritz Jaensch) as being from Chetchina, which he says is one of the Andreanof Islands.  Petroff (1884), translating Grewingk, reports 1760 and 1784 eruptions from Chechina.  Also derived from Grewingk, Dall (1870) and Becker (1898) report eruptions from Chechitno in 1760 and 1784.  Becker (1898) states: \"Mount Wrangell lies at a distance of about 134 miles from the head of Prince William Sound, and, according to Lieut. H. T. Allen, it reaches the great height of 17,500 feet.  It was steaming at the date of his visit.  It is the loftiest of a group of high mountains, one of which, named Mount Blackburn by Mr. Allen, is only 30 miles from the junction of the Copper River and the Tschichitna, Chechitna, or Chittyna River.  I suppose this latter mountain to be that called by earlier writers the Chechitno volcano.\"  Translation of Shmalev (found in Juergen Kienle's files) equates the Island of Chetkhina with Great Sitkin, which has historical accouts of eruptions in 1760 and 1784.  According to the Smithsonian Institution Chechitno is a synonym of Wrangell.  Additionally, according to  Grewingk (1850, translated 2003 by Fritz Jaensch), Mt. Wrangell was not discovered until 1819.","StartYear":1760,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Wrangell","ParentVolcano":"Wrangell","VolcanoID":"ak326","ParentVolcanoID":"ak326"},{"ID":185,"Name":"Pavlof 1762","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) reported Pavlof active from 1762-1786, and said that the northern crater collapsed in 1786.\r\n   Veniaminov (1840, translated by Lydia T. Black and R.H. Geoghegan, 1984) reports: \"Before 1786 the northern, or interior, half burned. In 1786, following an eruption, at the time of a severe earthquake and tremendous thunder, its upper part collapsed; at the same time the crater opened in the southern or shore-ward half, whence smoke is emitted to this day.\"\r\n    Hantke (1955) also reports: \"From 1762 to 1786, only the northern vent was active.  That crater was then closed off by a plug.  Eruptions then came out of southern vent.\"\r\n    Kennedy and Waldron (1955), McNutt (1985) suggests that some or all of this activity may be from Pavlof Sister, rather than Pavlof.  Coats (1950) lists this eruption as from Pavlof Sister.  Sapper (1927) estimates between 10^8 to 10^9 cubic meters of tephra were erupted.","StartYear":1762,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1786,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":554,"Name":"Pavlof Sister 1762","Description":"   Grewingk (1850) writes that promyshlenniks reported Pavlovskii Volcano active from 1762-1786, and that \"one of the craters closed up\" in 1786.  \r\n      Veniaminov (1840, translated by Lydia T. Black and R.H. Geoghegan, 1984) reports: \"Before 1786 the northern, or interior, half burned. In 1786, following an eruption, at the time of a severe earthquake and tremendous thunder, its upper part collapsed; at the same time the crater opened in the southern or shore-ward half, whence smoke is emitted to this day.\"\r\n   Coats (1950) attributes this eruption to Pavlof Sister, which is slightly north of Pavlof.  Kennedy and Waldron (1955) list this eruption under Pavlof, but state that any of the eruptions currently attributed to Pavlof may be from Pavlof Sister instead.  McNutt (1985) also suggests that this eruption may be from Pavlof Sister.\r\n   Sarychev (translated from Russian in 1806 and 1807, republished 1969) describes this eruption as follows: \"the lofty volcanic mountain on the shore of Alaksa, opposite to the island Unatchoch, the summit of which was torn off and hurled down with a tremendous crash, in an eruption in the year 1786.\"\r\n   Based on Sapper's classification scheme, Siebert and Simkin (2002-) list a tephra volume of greater than 5.5 +/- 5.0 x 10^8 cubic meters.","StartYear":1762,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1786,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof Sister","ParentVolcano":"Pavlof Sister","VolcanoID":"ak211","ParentVolcanoID":"ak211"},{"ID":30,"Name":"Tanaga 1763","Description":"   From Miller and others (1998):\"Few details are available concerning historical activity of Tanaga Volcano, and some or all of the events attributed to it may have involved adjacent cones in the northwest part of the island (Coats, 1950).\"\r\n   Grewingk (1850, translated 2003 by Fritz Jaensch) reports: \"1763-1770 constantly active (according to promyshlenniks).\"\r\n   From Sapper (1917): \"Tanaga smoking in 1763-1770.\"","StartYear":1763,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1770,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Tanaga","ParentVolcano":"Tanaga","VolcanoID":"ak280","ParentVolcanoID":"ak280"},{"ID":34,"Name":"Kanaga 1763","Description":"   From Grewingk (1850, translated 2003 by Fritz Jaensch): 1763, pg. 121: \"volcano with crater where sulfur was collected (solfatara), and hot springs (Tolstykh).  Page 122: \"Kanaga solfatara.\"   Coats (1950): 1763, Kanaga active; type of activity unspecified.","StartYear":1763,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kanaga","ParentVolcano":"Kanaga","VolcanoID":"ak144","ParentVolcanoID":"ak144"},{"ID":226,"Name":"Akutan 1765","Description":"   Coxe (1787) reports \"The flames of sulfur are occasionally seen at night upon the mountains of Unalaska and Akutan.\"  Jacob and Hauksson (1983) interpret this statement to mean eruptions at Akutan during the 1760's.","StartYear":1765,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":5,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":184,"Name":"Great Sitkin 1767","Description":"   In Juergen Kienle's files, Lydia Black has translated a portion of Divin (1979).  The passage is a synopsis of data from not later than 1774, written by Captain T. I. Shmalev, \"From the report of Captain T.I. Shmalev about Russian merchant expeditions and of that of the promyshlenniki to the Kurile and Aleutian Islands about the sea otter enterprise,\" pages 320-321.  Lydia Black's translation is as follows: \"There is on the Island of Chetkhina (Great Sitkin) a peak.  In 1767 it burned so strongly that form its interior earth/dust has been carried for a distance of over 30 versts.  The Tolbol'sk merchant Ushenin said that on the islands nearby the dust covered the grass knee-deep (he dug to the grasslayer).  The Aleuts who lived on that island and their chief Ula spoke that when the dust was emitted, it was preceded and accompanied by great noise, and there were great tremors.  Two twenty-four hour periods one could not see the light of the sun at all.  The waters in the sea were much disturbed and from it multitude of fish perished and were cast out, a great number of birds were covered with dust, a great many stifled, and the animals, too, such as sea otters, diminished in numbers.  The Aleuts say that not only did they never witness such, but they have not even heard about something like this from their old people.  Before this eruption, the mountain just burned with a flame.  Nowadays, there is no flame and not even smoke.  Where the burned earth landed, grasses do not grow even now.  The Aleuts state that this burned earth is burned stones.  The Aleuts saved themselves as this burned earth did not cover their village, falling about 2 verst from it.  The promyshlenniki thank God for that that the village and people were saved, as the chief of that island is considered a friend of the Russians.\"","StartYear":1767,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":414,"Name":"Iliamna 1768","Description":"   Sapper (1917) reports Iliamna active in 1768.  However,  Grewingk (1850, translated 2003 by Fritz Jaensch) does not mention Iliamna active in 1768, but does quote Cook as saying Iliamna was active in 1778.  Cook (1795, reprinted by Beaglehole, 1967) does mention smoke from Iliamna in 1778.  Perhaps the 1768 date is a typographical error made by Sapper.","StartYear":1768,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":124,"Name":"Makushin 1769","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) writes that Krenitsyn reported \"two volcanoes active on Unalaska\" in 1768.  He also writes that there are two fire-belching mountains on Unalaska in 1768-69.  Although one of these volcanoes is certainly Makushin, the \"other\" volcano's name and location are unknown.  There is some discrepancy about the duration of this eruption.  Grewingk (1850, translated 2003 by Fritz Jaensch) mentions only Krenitsyn's account in 1768 and that Cook in 1778 reported the island inactive.  However, McGimsey and Miller (1995), and Miller and others (1998) report the dates of this eruption as from 1768-1779; Powers (1958), Jacob and Hauksson (1983), Simkin and Siebert (1994), and Beget and others (2000) report the dates as 1768-1769.  Powers (1958) also specifies that this was an ash eruption; many subsequent compilers state that this was a violent ash eruption, or a major eruption.","StartYear":1769,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1769,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":90,"Name":"Amukta 1770","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) writes that Amukta was \"with active volcano until this year [1770].\"  Becker (1898) and Dall (1870) translate this statement as 1770 being the year Amukta became quiet.","StartYear":1770,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":10,"StartQualifierUnit":"Years","EndYear":1770,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Amukta","ParentVolcano":"Amukta","VolcanoID":"ak10","ParentVolcanoID":"ak10"},{"ID":11,"Name":"Mount Young 1772","Description":"   From Miller and others (1998): \"Records of volcanism on Semisopochnoi Island are scant; historical eruptions could have involved the small Lakeshore Cone and Sugarloaf cone in addition to Mount Cerberus [Mount Young].  However, since at least one of the early reports specified that the activity noted was in the center of the island, and Mount Cerberus is the least eroded of the recent cones, it is believed to have been the source of most recorded events (Coats, 1950; 1959).\"\r\n   From Grewingk (1850, translated 2003 by Fritz Jaensch): \"1772, Semisopochnoi smoking.\"","StartYear":1772,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mount Young","ParentVolcano":"Semisopochnoi","VolcanoID":"ak44","ParentVolcanoID":"ak248"},{"ID":104,"Name":"Carlisle 1774","Description":"   Documentation of early eruptions in the Islands of the Four Mountains region is scanty and uncertain.  Previous compilers (Simkin and Siebert, 1994; Miller and others, 1998) have assigned this eruption to Carlisle.  Based on descriptive information found in Veniaminov (1840, translated by Lydia T. Black and R.H. Geoghegan, 1984) and  Grewingk (1850, translated 2003 by Fritz Jaensch), this eruption has been reassigned to Cleveland.  Please refer to Cleveland's eruptive history for information about this event.","StartYear":1774,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Carlisle","ParentVolcano":"Carlisle","VolcanoID":"ak40","ParentVolcanoID":"ak40"},{"ID":282,"Name":"Cleveland 1774","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) reports \"Tanak-Angunak active in 1774.\"  There is some confusion as to whether \"Tanak-Angunach\" refers to Carlisle volcano or Mount Cleveland.  From Miller and others (1998): \"Various names were applied to Carlisle on early hydrographic charts, including Uliaga, Kigalgin and variants thereof; it was also sometimes referred to along with the western half of Chuginadak Island, as Tanak-Angunak.  It is thus possible that some of the activity ascribed to Carlisle should be attributed to Uliaga or Mount Cleveland (Coats, 1950).\"\r\n   In support of this particular  \"Tanak-Angunak\" referring to Chuginadak Island (the island Cleveland Volcano forms the western half of) is Grewingk's description of Tanak-Angunak:  \"* * * oblong with a steep south side.  An active volcano rises on its western side.  According to an Aleutian legend it once formed an island by itself.  But the dividing strait was filled in when a mountain collapsed.  At the foot of this mountain there is a spring so hot that it can be used to cook in.\"  This description fits with the two part appearance of Chuginadak Island, and does not match the single-circle shape of Carlisle Island.","StartYear":1774,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":343,"Name":"Shishaldin 1775","Description":"   From Veniaminov (1840, translated by Lydia T. Black and R.H. Geoghegan, 1984): \"About 1795, with the wind from the SW, the range on the SW end of Unimak blew up with a terrible thunder and an eruption of ash [pepel] or soot [sazha], white in color, in such a great quantity that, for several hours in the middle of the day, not only in the neighboring villages on Aliaksa but even on Unga, there was absolute darkness.  The eternal ice, lying on that range, slid down along both sides together with a large quantity of water and burned rocks of different sizes.  The last stopped about half-way along and formed a trench or a black belt visible even now.  There are still signs in place where the water flows and where the ice, which had slid down the mountain, rested for several years (the vegetation has only just begun to appear there).\"\r\n   From  Grewingk (1850, translated 2003 by Fritz Jaensch): \"From Zaikov's report (Pallas, N.B. III, p. 281) we receive the first detailed news about Unimak, on which island he sojourned from 1775 to 1778.  'The western promontory is rocky on both sides, and steep; and the shoreline is sandy, precipitous, and full of sandbars.  The middle of the island is mountainous; and there is a volcano (Shishaldin), which is frequently on fire.'\"\r\n   And  Grewingk (1850, translated 2003 by Fritz Jaensch) continues \"Cook (Vol.  II, p. 117, [Eng. ed., London, 1784, vol. 2, p. 416]) sighted this volcano on the twenty-first of June 1778, and fixed its location at 54 degrees, 48 minutes N. Lat. And 164 degrees 15 minutes W. Long.  He believed, however, that it still belonged to the mainland.  'Over this [Halibut Island, Sanak] and the adjoining islands we could see the main land covered with snow; but particularly, some hills, whose elevated tops were seen, towering above the clouds, to a most stupendous height.  The most South Westerly of these hills was discovered to have a volcano, which continually threw up vast columns of black smoke.'  This obviously was Shishaldin Mountain of Unimak.\"","StartYear":1775,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1775,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":8,"Name":"Little Sitkin 1776/6","Description":"   Grewingk (1850: \"1776, In July Mt. Sitignak belching fire.\"  Coats (1950) states that this eruption was probably at Little Sitkin.","StartYear":1776,"StartMonth":6,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Little Sitkin","ParentVolcano":"Little Sitkin","VolcanoID":"ak182","ParentVolcanoID":"ak182"},{"ID":434,"Name":"Redoubt 1778","Description":"   Captain James Cook saw Redoubt during the summer of 1778, \"emitting a white smoke but no fire which made some think it was no more than a white thick cloud such as we have frequently seen on the Coast, for the most part appearing on the sides of hills and often extends along a whole range and at different times falls or rises, expands or contracts itself and has a resemblance to Clouds of white smoke.  But this besides being too small for one of those clouds, remained as it were fixed in the same spot for the whole time the Mountain was clear which was above 48 hours\" (Beaglehole, 1967).\r\n   Kisslinger (1983), translating Doroshin (1870) notes that George Vancouver was also in the area in 1778 (Lamb, 1984) and does not make any mention of Redoubt steaming.  \r\n   Although Simkin and Siebert (1994) called this event a questionable volcanic eruption, the Smithsonian Volcanoes of the World online database now calls this event a discredited eruption, stating that there was no ash emission during this event.  Wood and Kienle (1990) also do not call this event an eruption.","StartYear":1778,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Redoubt","ParentVolcano":"Redoubt","VolcanoID":"ak231","ParentVolcanoID":"ak231"},{"ID":415,"Name":"Iliamna 1778/5","Description":"   Beaglehole (1967) writes that Cook reported \"white smoke but no fire seen\" at Iliamna in May, 1778.","StartYear":1778,"StartMonth":5,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":417,"Name":"Iliamna 1779","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) listed Iliamna as active in 1779, as reported by Arteaga.","StartYear":1779,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":106,"Name":"Vsevidof 1784","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) writes that Vsevidof was smoking in 1784, and had hot springs at its base.","StartYear":1784,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Vsevidof","ParentVolcano":"Vsevidof","VolcanoID":"ak307","ParentVolcanoID":"ak307"},{"ID":159,"Name":"Great Sitkin 1784","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) reports that Shelikhov reported Mt. Moffet active in 1784, with hot springs.  However, Mt. Moffet does not appear to have had any historical eruptions, and perhaps the eruption was from Great Sitkin instead (Hantke, 1951; Simkin and Siebert, 1994; and Waythomas and others, 2003).","StartYear":1784,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":396,"Name":"Wrangell 1784/6","Description":"   The 1760 and 1784 eruptions of Wrangell are questionable, poorly documented, and may in fact refer to a volcano other than Mt. Wrangell.  Dall (1870) says that \"Chechitno\" smoked in 1760, and erupted in July 1784.\r\n   These eruptions are first reported by  Grewingk (1850, translated 2003 by Fritz Jaensch) as being from Chetchina, which he says is one of the Andreanof Islands.  Petroff (1884), translating Grewingk, reports 1760 and 1784 eruptions from Chechina.  Also derived from Grewingk, Dall (1870) and Becker (1898) report eruptions from Chechitno in 1760 and 1784.  Becker (1898) states: \"Mount Wrangell lies at a distance of about 134 miles from the head of Prince William Sound, and, according to Lieut. H. T. Allen, it reaches the great height of 17,500 feet.  It was steaming at the date of his visit.  It is the loftiest of a group of high mountains, one of which, named Mount Blackburn by Mr. Allen, is only 30 miles from the junction of the Copper River and the Tschichitna, Chechitna, or Chittyna River.  I suppose this latter mountain to be that called by earlier writers the Chechitno volcano.\"  Translation of Shmalev (found in Juergen Kienle's files) equates the Island of Chetkhina with Great Sitkin, which has reported eruptions in 1760 and 1784.  According to the Smithsonian Institution Chechitno is a synonym of Wrangell.  Additionally, according to  Grewingk (1850, translated 2003 by Fritz Jaensch), Wrangell is not discovered until 1819.","StartYear":1784,"StartMonth":6,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Wrangell","ParentVolcano":"Wrangell","VolcanoID":"ak326","ParentVolcanoID":"ak326"},{"ID":80,"Name":"Seguam 1786","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) states that from 1786 until 1790, Seguam was active.  Sarychev (translated from Russian in 1806 and 1807, republished 1969) wrote that in 1790, Seguam was \"formerly to have had a volcanic mountain.\"","StartYear":1786,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1790,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Seguam","ParentVolcano":"Seguam","VolcanoID":"ak246","ParentVolcanoID":"ak246"},{"ID":157,"Name":"Kanaga 1786","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) reports that Shelikhov said Kanaga was erupting with fire in 1786.","StartYear":1786,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kanaga","ParentVolcano":"Kanaga","VolcanoID":"ak144","ParentVolcanoID":"ak144"},{"ID":418,"Name":"Iliamna 1786","Description":"   From Kisslinger (1983), translating Doroshin (1870): \"Portlock and Dickson, who were at the entrance to Kenai Bay in 1786, appended to the description of their journey a view of Iliamna giving off smoke.  It has not ceased smoking since that time. Smoke can be distinguished in three places: on the southeast side of the mountain, a little below the summit; from the cone found on the eastern rim, also below the summit; and from a third location, visible only under special conditions, which I did not encounter.\"","StartYear":1786,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":91,"Name":"Amukta 1786/6","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) writes that Shelikov reported Amukta \"all in flames\" in June of 1786, and Sarychev reported it active in 1790.  In Grewingk's chronological table of eruptions, he writes that Amukta was active from 1786 through 1791.  The English translation of Sarychev is less clear: \"On the morning of the 29th we passed the island Amuchta at a distance of 6 miles.  It is about 27 miles in extent, and is said to have a volcano.\"\r\n   Shelikhov (translated in 1981 by Marina Ramsay) writes: \"During this voyage [the return] we saw the Islands of the Four Mountains and Amukhta.  Because of active volcanoes the latter seemed to be enveloped in flame.\"\r\n   Sapper (1927) estimates a tephra volume of 10^7 to 10^9 for this eruption; the Smithsonian Global Volcanism Database uses this estimate and, in turn, estimates a tephra volume of 5.1 +/- 5.0 x 10^8 cubic meters.","StartYear":1786,"StartMonth":6,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1791,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Amukta","ParentVolcano":"Amukta","VolcanoID":"ak10","ParentVolcanoID":"ak10"},{"ID":12,"Name":"Mount Young 1790","Description":"   From Miller and others (1998): \"Records of volcanism on Semisopochnoi Island are scant; historical eruptions could have involved the small Lakeshore Cone and Sugarloaf cone in addition to Mount Cerberus [Mount Young].  However, since at least one of the early reports specified that the activity noted was in the center of the island, and Mount Cerberus is the least eroded of the recent cones, it is believed to have been the source of most recorded events (Coats, 1950; 1959).\r\n   From Grewingk (1850, translated 2003 by Fritz Jaensch): \"Semisopochnoi smoking in 1790.\"","StartYear":1790,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mount Young","ParentVolcano":"Semisopochnoi","VolcanoID":"ak44","ParentVolcanoID":"ak248"},{"ID":18,"Name":"Gareloi 1790","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) states that Sarychev passed Gareloi on the twenty-fourth of September, 1790 and on June 17, 1791 and described Gareloi as a \"very tall, snow-covered, fire-belching mountain.\"  It is uncertain if an eruption was observed on either or both of these occasions.  The English translation of Sarychev (translated from Russian in 1806 and 1807, republished 1969) makes no mention of \"fire-belching\" and instead simply states that Gareloi was covered in \"eternal snow.\"  Coats (1950): reports minor explosive activity at Gareloi in 1790.  Petroff (1884), Becker (1898), and Dall (1870) make no mention of this dubious eruption.\r\n   Sauer's account (1802) of the same voyage that Sarychev was on does mention Gareloi on the 24th of September, 1790, and June 17, 1791, but makes no mention of volcanic activity.","StartYear":1790,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Gareloi","ParentVolcano":"Gareloi","VolcanoID":"ak106","ParentVolcanoID":"ak106"},{"ID":35,"Name":"Kanaga 1790","Description":"   From Grewingk (1850, translated 2003 by Fritz Jaensch): \"1790 and 1791, smoke rising from the hot springs at the base of a once-active volcano (Sauer, Sarychev).\"  Coats (1950): 1790, Kanaga was \"active; type of activity unspecified.\"  Sauer, June 17, 1791: \"We made the island of Kanaga seven miles distant from that of Tanaga, and saw the smoke ascending from the hot spring at the base of an extinguished volcano on the island of Kanaga, off which at 12 miles we also observed the small island called Bobrovoi, from the number of sea-otters that formerly held their resting-place upon it.\"","StartYear":1790,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kanaga","ParentVolcano":"Kanaga","VolcanoID":"ak144","ParentVolcanoID":"ak144"},{"ID":186,"Name":"Pavlof 1790","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) writes that Sarychev reported Pavlof active in 1790.  The English translation of Sarychev (translated from Russian in 1806 and 1807, republished 1969) makes no mention of Pavlof being active in 1790.\r\n   Sapper (1917) reports that the southern vent of Pavlof was active.","StartYear":1790,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":344,"Name":"Shishaldin 1790/4","Description":"   From  Grewingk (1850, translated 2003 by Fritz Jaensch): \"In Sauer (Billings's exped. [Sauer, Eng. Ed., London, 1802, p. 164]) it states: '[The terrain of Unimak Island] is high, broken, and rugged, and there are three very conspicuous mountains upon it.  The summit of the first [Pogromnaia?] is very irregular; the second [Shishaldin] is a perfect cone towering to an immense height, and discharging a considerable body of smoke from its summit [19 April 1790]; the third (Khaginak) has its summit apparently rent and broken, covered with snow, and towering above the fog which covered the middle of the land.'  Sarichev (II, pp. 28-29, with two profiles) sighted the three sugarloaf-shaped mountains on the eighteenth of June 1790.  He named them Agayedan (Shishaldin), Khagman (Khaginak), and Kugidahk-Yagutcha (Pogromnaya).  The first of them was smoking; the second had the appearance of a caved-in cone.\"\r\n   The English translation of Sarychev states that on June 17, 1790, at ten o'clock, \"we discovered the conical summits of the island of Unimak, one of which, called Agagedan, is likewise volcanic, and at that time emitted a thick smoke.\"","StartYear":1790,"StartMonth":4,"StartDay":19,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1790,"EndMonth":6,"EndDay":18,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":107,"Name":"Vsevidof 1790/5","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) writes that Sarychev reported Vsevidof smoking in 1790.  Coats (1950) reports smoke on May 30, 1790.  The English translation of Sarychev is less clear - for the 30th of May, it reads: \"The island Umnak is level on its western side, but elevated towards the north-east.  It extends as far as the strait which separates it from Unalaschka, and terminates with mountains; several of which, rising above the others, are volcanic, and crowned with eternal snow.  It stretches, from south-west to north-east, 55 miles in length.  The strait between Umnak and Unalaschka is at least 2 miles and a half in width.  About 30 versts from the strait, and about 7 miles from Umnak, are two rocks, surrounded by water; which, on the 31st of May, lay five miles distant towards the north-west.  We were then in latitude 52 degrees 49 minutes; and longitude 192 degrees 45 minutes.\"","StartYear":1790,"StartMonth":5,"StartDay":30,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Vsevidof","ParentVolcano":"Vsevidof","VolcanoID":"ak307","ParentVolcanoID":"ak307"},{"ID":125,"Name":"Makushin 1790/6","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) quotes Sarychev: \"On the seventh of June 1790, the Makushin volcano was smoking.  But it has not burned for a long time.  Only now and then (on Feb. 14, 1792) did it expel smoke.\"  The English translation of Sarychev does mention that he saw Makushin on those dates, but is unclear whether or not he saw smoke from Makushin: \"It is higher than all the other mountains of Unalaska, with a summit more level than pointed; that on the southern side of the island has the appearance of being almost flat; all eruptions have long since ceased, and nothing now remains but occasional smoke.  Earthquakes are likewise now very rare, which were formerly frequent and so violent as to overturn jurts and pendant rocks.  On the summit of this crater the Aleutians collect sulphur and lava; from which the latter they make points for their darts.\"","StartYear":1790,"StartMonth":6,"StartDay":7,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":227,"Name":"Akutan 1790/6","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) writes that Sauer and Sarychev reported Akutan smoking on June 7, 1790 [Julian calendar date].  The English translation of Sarychev states that on June 17, 1791 \"At midnight a thick mist arose, which lasted till seven in the morning, when the island Atrutan, with its smoking crater, and the circumjacent islets, gradually opened to view.\"  Sauer states that they saw the island of Akutan on June 18th, 1791 [Gregorian calendar date], and makes no mention of smoke.","StartYear":1790,"StartMonth":6,"StartDay":18,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":19,"Name":"Gareloi 1791","Description":"   Coats (1950): minor explosive activity at Gareloi in 1791.  Grewingk (1850, translated 2003 by Fritz Jaensch) states that Sarychev passed Gareloi on the twenty-fourth of September, 1790 and on June 17, 1791 and described Gareloi as a \"very tall, snow-covered, fire-belching mountain.\"  It is uncertain if an eruption was observed on either or both of these occasions.  Petroff (1884), Becker (1898), and Dall (1870) make no mention of this eruption.","StartYear":1791,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Gareloi","ParentVolcano":"Gareloi","VolcanoID":"ak106","ParentVolcanoID":"ak106"},{"ID":31,"Name":"Tanaga 1791/6","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch): Sauer and Sarychev saw smoking on the 9th of June, 1791.  The English translation of Sarychev (translated from Russian in 1806 and 1807, republished 1969) makes no mention of smoking, and reads: \"we were presented with the spectacle of a lofty volcanic mountain, that exposed to our view, at the distance of scarcely two miles, its black and tremendously tall side of rock.\"\r\n   Sauer (1802) writes that on the 9th of June, 1791, \"At first we took the rock for the Volcano Gorelloi; but soon discovered it to be the northwest extremity of Tanaga, which is formed by an uneven-topped volcano, appearing like a cluster of mountains.  One terminates in a conical point, of extreme height, emitting sometimes a column of smoke.  They are all covered with snow, which descends in ridges to below the middle of the mountain, but much darkened by the quanity of ashes upon it.\"","StartYear":1791,"StartMonth":6,"StartDay":9,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Tanaga","ParentVolcano":"Tanaga","VolcanoID":"ak280","ParentVolcanoID":"ak280"},{"ID":36,"Name":"Kanaga 1791/6","Description":"   From Grewingk (1850, translated 2003 by Fritz Jaensch): \"According to Sauer (Engl., p. 226, German, p. 259) and Sarychev (II, p. 76) smoke was seen on the seventeenth of June 1791.  It came from the hot springs of the formerly active volcano.\"  \r\nCoats (1950) reports smoke at Kanaga in 1791.","StartYear":1791,"StartMonth":6,"StartDay":17,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kanaga","ParentVolcano":"Kanaga","VolcanoID":"ak144","ParentVolcanoID":"ak144"},{"ID":20,"Name":"Gareloi 1792","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch): Gareloi \"belching fire until the end of May\" and smoking during 1792.","StartYear":1792,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Gareloi","ParentVolcano":"Gareloi","VolcanoID":"ak106","ParentVolcanoID":"ak106"},{"ID":126,"Name":"Makushin 1792/2","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) quotes Sarychev: \"On the seventh of June 1790, the Makushin volcano was smoking.  But it has not burned for a long time.  Only now and then (on Feb. 14, 1792) did it expel smoke.\"  The English translation of Sarychev does mention that he saw Makushin on those dates, but is unclear whether or not he saw smoke from Makushin: \"It is higher than all the other mountains of Unalaska, with a summit more level than pointed; that on the southern side of the island has the appearance of being almost flat; all eruptions have long since ceased, and nothing now remains but occasional smoke.  Earthquakes are likewise now very rare, which were formerly frequent and so violent as to overturn jurts and pendant rocks.  On the summit of this crater the Aleutians collect sulphur and lava; from which the latter they make points for their darts.\"","StartYear":1792,"StartMonth":2,"StartDay":14,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":48,"Name":"Great Sitkin 1792/5","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) reports that in 1792 Sarychev said Great Sitkin was \"belching fire until the end of May.\"  The English translation of Sarychev makes no mention of this date or Great Sitkin.","StartYear":1792,"StartMonth":5,"StartDay":26,"StartTime":null,"StartQualifier":5,"StartQualifierUnit":"Days","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":13,"Name":"Mount Young 1792/6","Description":"   From Miller and others (1998): \"Records of volcanism on Semisopochnoi Island are scant; historical eruptions could have involved the small Lakeshore Cone and Sugarloaf cone in addition to Mount Cerberus [Mount Young].  However, since at least one of the early reports specified that the activity noted was in the center of the island, and Mount Cerberus is the least eroded of the recent cones, it is believed to have been the source of most recorded events (Coats, 1950; 1959).\"\r\n   From Grewingk (1850, translated 2003 by Fritz Jaensch): \"Sarychev observed \"thick smoke\" from a not-very-high peak on the eastern end of Semisopochnoi Island on the first of June, 1792.\"\r\n  Sauer reports slightly differently: \"and on this same day [June 7, 1792] saw an island, which we took for Semi Soposhni, burning in several places, particularly toward the southern extremity.\"","StartYear":1792,"StartMonth":6,"StartDay":1,"StartTime":null,"StartQualifier":7,"StartQualifierUnit":"Days","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mount Young","ParentVolcano":"Semisopochnoi","VolcanoID":"ak44","ParentVolcanoID":"ak248"},{"ID":420,"Name":"Iliamna 1793","Description":"   Sapper (1917) lists smoke from Iliamna in 1793.","StartYear":1793,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":406,"Name":"Fisher 1795","Description":"   From Veniaminov (1840, translated by Lydia T. Black and R.H. Geoghegan, 1984): \"The low peak in the interior of Unimak Island, near its south end, burned until the upheaval of the southwest range, in 1795, then was extinguished.\"  Possibly Veniaminov is referring to Fisher Caldera.","StartYear":1795,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Fisher","ParentVolcano":"Fisher","VolcanoID":"ak100","ParentVolcanoID":"ak100"},{"ID":271,"Name":"Westdahl 1795","Description":"   From Miller and others (1998): \"Veniaminov (1840, p. 18) described an eruption in 1795 on the southwest end of Unimak Island, which most likely occurred at Westdahl.  Coats (1950) attributed four eruptions in the late eighteenth century and early nineteenth century to Pogromni volcano.  Based on recent observations from aircraft, however, Pogromni does not appear to have been active in historical time.  The eruptions should probably be assigned to Westdahl.\"\r\n   From Veniaminov (1840, translated by Lydia T. Black and R.H. Geoghegan, 1984): \"In regard to volcanic phenomena, Unimak Island has occupied the first place since antiquity, both for its extraordinary size or the height and position of the mountains located on it.  About 1795, with the wind from the SW, the range on the SW end of Unimak blew up with a terrible thunder and an eruption of ash [pepel] or soot [sazha], white in color, in such a great quantity that, for several hours in the middle of the day, not only in the neighboring villages on Aliaksa but even on Unga, there was absolute darkness.  The eternal ice, lying on that range, slid down along both sides together with a large quantity of water and burned rocks of different sizes.  The last stopped about half-way along and formed a trench or a black belt visible even now.  There are still signs in places where the water flows and where the ice, which had slid down the mountain, rested for several years (the vegetation has only just begun to appear there).  Nowadays one notices that this very range, which had been at rest after the upheaval, in the last few years, in one place, began to grow or bulge out.\"\r\n   Additionally, Plummer (1898) reports that the southwest crater exploded and fell in.\r\n   Sapper (1927) assigns this eruption to his category b1, and estimates more than 1 cubic km (10^9 cubic m) of tephra was erupted.","StartYear":1795,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Westdahl","ParentVolcano":"Westdahl","VolcanoID":"ak322","ParentVolcanoID":"ak322"},{"ID":448,"Name":"Isanotski 1795","Description":"   Several historical eruptions have been attributed to Isanotski, most notably the explosive March 10, 1825 eruption.  However, according to Alaska Volcano Observatory geologists, Isanotski shows no evidence of having any possibly Holocene vents.  Alaska Volcano Observatory geologists flying over Isanotski in 1997, 1998, and 1999 failed to find any apparently Holocene vents on Isanotski, and saw only glacially polished rocks.  Geologists from AVO insist that all historical eruptions of Isanotski instead be attributed to Shishaldin.  Field investigations of Shishaldin reveal numerous Holocene vents, including a very large flank feature called \"The Blister\" that has melted through the modern ice cover of Shishaldin, and which could be the vent for eruptions during the 1800s.  In addition, several streams draining from Shishaldin look capable of carrying large amounts of sediment to the sea (as described by Veniaminov for the March 10, 1825 eruption), but all of the streams draining Isanotski are heavily vegetated, suggesting that they did not carry large amount of sediment within the last few hundred years (Chris Nye, personal commun., 2004).\r\n   Coats (1950) lists Isanotski as erupting in 1795, but Veniaminov (1840) and Grewingk (1850) indicate differently.  Veniaminov reports that \"a small mountain peak located not far away [from Pogromni] began to burn and continued to emit flame until 1795 or until the upheaval of the southwest range, lying to the S of Pogromskaia sopka.\"  From this description, the 1795 activity is probably from Westdahl.","StartYear":1795,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Isanotski","ParentVolcano":"Isanotski","VolcanoID":"ak135","ParentVolcanoID":"ak135"},{"ID":127,"Name":"Makushin 1796","Description":"   Dall (1884) writes that in 1796, disturbances on nearby Bogoslof were accompanied by volcanic activity in the craters of Makushin on Unalaska Island, as well as in craters of volcanoes on Umnak Island.\r\n   Sapper (1917) reports underwater explosions off the southeast coast [of Unalaska] in 1795.  Perhaps this date is in error and should be in 1796.  If so, this report could be talking about Bogoslof, or about some other submarine activity near Unalaska.","StartYear":1796,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":272,"Name":"Westdahl 1796","Description":"   From Miller and others (1998): \"Coats (1950) attributed four eruptions in the late eighteenth century and early nineteenth century to Pogromni volcano.  Based on recent observations from aircraft, however, Pogromni does not appear to have been active in historical time.  The eruptions should probably be assigned to Westdahl.\"\r\n   Sapper (1917) reports that in 1796 ice and water came pouring down to a town called Nosowskoi.  Coats (1950) reports a lava flow or plug dome and some explosive activity.\r\nSimkin and Siebert (1994) assign the eruption a VEI of 0, indicating a non-explosive eruption.","StartYear":1796,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Westdahl","ParentVolcano":"Westdahl","VolcanoID":"ak322","ParentVolcanoID":"ak322"},{"ID":270,"Name":"Amak 1796","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) reports that in 1796, Amak \"with active crater (?).\"  Grewingk also writes that Amak has been dormant at least since 1804, when Krusenstern viewed the island.  Marsh (in Wood and Kienle, 1990) states that \"granular, blocky leveed flows have erupted in historic times.\"\r\nFrom Marsh and Leitz (1978): \"The younger series of flows issued from a central vent located slightly south of the initial crater. These lavas breached the initial summit crater on the south and, at least in part, flowed down pre-existing glacially-cut valleys. These flows are chaotic, and wholly comprised of large angular blocks ranging in size from 0.1 m to several meters. Most blocks show traces of having been sheared and granulated. The lava is dark gray with a porous and sugary texture. At the outer margin of the southern flank this series has an apparent thickness of about 100 m. Moss and lichen growth on these flows, confirm that two periods of eruption produced this younger series. A thin layer (1 cm) of volcanic ash caps some of the larger blocks; this ash is probably from nearby Shishaldin volcano on Unimak Island, which has been active intermittently for at least the last 200 years (Coats 1950).\"\r\n\"According to Funk (1973) the latest period of glaciation in this area was about 6,700 years B.P. The small U-shaped glacial valley cut into the older series was probably excavated during this period of glaciation. The older flows also show no sign of being extruded beneath ice. Thus Amak is probably not much older than 6,700 years. Early explorers (Dall 1897) reported volcanic activity on Amak during 1700-1710 and 1796 but report that by 1867 all activity had ceased. The younger series of flows was, surely, extruded during these times.\"","StartYear":1796,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Amak","ParentVolcano":"Amak","VolcanoID":"ak8","ParentVolcanoID":"ak8"},{"ID":112,"Name":"Bogoslof 1796/5","Description":"   From Miller and others (1998): \"A small rocky prominence, called Ship Island or Ship Rock, was observed in 1768 by Russian explorers at the approximate site of Bogoslof Island; it disappeared through marine erosion by the end of the 19th century and little is known concerning its composition and origin (Byers, 1959).  An explosive eruption of debris in 1796, followed by extrusion of viscous lava, built a second island by 1804, about 0.6 km south of Ship Rock.  The second island was known successively as Ioann Bogoslof, Old Bogoslof, and Castle Rock.  The vent agglomerate and hornblende andesite of Castle Rock, exposed on the southwest end of modern Bogoslof Island, represent early and late products, respectively, of this eruption (Byers, 1959).\"\r\n   There is some discrepancy concerning the start date of this eruption.  Grewingk (1850, translated 2003 by Fritz Jaensch) and Dall (1870, 1884) report Baranov writing that this eruption began on the first of May, 1796.  Grewingk (1850, translated 2003 by Fritz Jaensch) writes that Kotzebue reported the eruption on the 7th of May (18th new style [Julian vs. Gregorian calendars]).  Regardless of the specific date, it seems clear that the eruption did begin in early May,1796.\r\n   Grewingk (1850, translated 2003 by Fritz Jaensch) summarizes Baranov's report as follows: \"According to Baranov's report there suddenly arose a storm from the north on the first day of May 1796; and the sky grew dark, which lasted the whole day.  During the following night the storm increased.  On this and the following day a muffled din could be heard, and a far-off crashing sound, which resembled thunder.  At the break of the third day the storm abated and the sky cleared.  And now a flame was observed between Unalaska and Umnak, and north of the last-named island.  It arose from the sea.  And soon there was smoke, which lasted ten consecutive days.  After that time something white, of rounded shape, was observed rising above the surface of the sea; and it grew very rapidly in size.\"  Grewingk (1850, translated 2003 by Fritz Jaensch) quotes Kotezebue's account of the eruption as follows:  \"On the 7th (18th New Style) of May 1796, an agent of the Russian American Company, Mr. Kriukov, was on the northernmost point of Umnak.  Storm from NW had obscured the view toward the sea.  On the 8th, the sky cleared up; and now a column of smoke could be observed rising from the sea a few miles off shore.  Toward evening there was something black, which arose beneath the column of smoke just a little above the surface of the water.  During the night, fire spouted upward from that location.  At times this was so strong, and the amount so large, that on this 10-mile-distant island (25 versts, according to Veniaminov, I., p. 156) all objects could easily be discerned.  Now an earthquake shook the island, and a horrible din echoed back from the mountains in the south.  The emerging island threw boulders all the way to Umnak.  With sunrise the earthquakes abated, the fire diminished.  And now the newly emerged island could be seen in the shape of a pointed hat.  One month later Mr. Kriukov found the island significantly taller.  It had in the meantime continued to expel fire.  Since then it has continued to grow in circumference and elevation; but the flames have abated, and only steam and smoke remain to be seen continuously.\"\r\n   Grewingk (1850, translated 2003 by Fritz Jaensch) further summarizes eruption details: \"Four years later no more smoke was seen; and eight years later (1804) hunters visited the island.  They found that the water was warm; and the ground was still so hot that in many places it could not be walked on.  Even a long time thereafter the island continued to grow in circumference and size.  A Russian of very healthy judgment reported that the circumference amounted to 2.5 miles; the elevation to 350 feet.  In the surrounding 3 miles the sea is covered with rocks.  From the middle of the island to the point, he found that it was warm.  And the steam, which arose from the crater, had a pleasant odor, probably from the mountain oil.\"  \"The elevation of St. J. Bogoslof is probably judged too low, according to Buch.  At such a circumference the elevation should easily have been several thousand feet.  Langsdorff's expression points up the same thing, when from his own perspective he calls the elevation a medium one.  When he got his first view of the island on August 18, 1806, there were four conical mountains visible on the NW side.  They rose by steps to a medium and highest elevation.  The latter seemed to rise on all sides vertically like a column.\"  Grewingk (1850, translated 2003 by Fritz Jaensch) also writes that Langsdorff report the island to be 10-15 versts in circumference.\r\n   Reports of this eruption's impact on human or animal populations is generally not available, although Ransom (1948) writes that \"* * * natives huddled in abject terror before their sod houses while fear crawled icily along their spines\" and \"Whole villages were wiped out as volcanic ash filled the sky and floated like wind-spume on the ocean.  There it mixed with millions of bellied-up fish, cooked to a seething pulp by the boiling sea.  Then came deluges of drenching rain greater than anything ever before known in those proverbially rainy, stormy regions.\"  Ransom's descriptions are not found in any other historical reference and seem to owe more to imagination than to historical fact.\r\n   Newhall and Melson (1983) estimate the size of 1796 lava dome to be about 10x10^6 cubic meters.  Based on Sapper's (1927) classification scheme, the Smithsonian Institution's online database of global volcanism estimates a tephra volume of 5.5 +/- 5 x 10^8 cubic meters.","StartYear":1796,"StartMonth":5,"StartDay":18,"StartTime":null,"StartQualifier":10,"StartQualifierUnit":"Days","EndYear":1804,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":6,"EndQualifierUnit":"Months","Volcano":"Bogoslof","ParentVolcano":"Bogoslof","VolcanoID":"ak29","ParentVolcanoID":"ak29"},{"ID":2601,"Name":"Iskut-Unuk River cones 150 yBP","Description":"From Hauksdottir and others (1994): \"The youngest flow erupted from a vent located on a ridge on the eastern side of Lava Fork valley. The lava flowed south, along the valley and southeast along Blue River valley, damming the river and forming Blue Lake. Near the main vent, the volcanic rocks overly basement rocks, including foliated biotite-quartz-schist intruded by granodiorite.\"\r\n\"Near its source, the youngest lava flow has ropey pahoehoe surfaces and forms well-developed small lava channels and lava tubes. Spatter, cinder and ash are abundant around the vent. Downslope and away from the vent, the flow surface abruptly changes to aa and splits into two main streams (north and south forks). The lava streams form large channels (Fig. 10 [in original text]) with several generations of prominent levees. Accretionary lava balls are common on the flow surface of the north fork lava (Sta. 23). They are approximately 5 m in diameter and consist of a red cinder breccia coated by massive flow which exhibits radially oriented irregular jointing. Xenoliths of basement rocks occur in both the interior and exterior portions of the lava balls.\"\r\n\"Grove (1986) argued for an age of 130 BP based on 14c dating of material associated with the lower flows. Subsequent dating, using tree-ring counts, gives a minimum age of 70 years old for the youngest flow (B.C. Hydro, 1985). Based on tree ring counts on living trees, and observations of the lava flow surface it is estimated to be around 150 years old.\"","StartYear":1800,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1880,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iskut-Unuk volcanic field","ParentVolcano":"Iskut-Unuk volcanic field","VolcanoID":"ak136","ParentVolcanoID":"ak136"},{"ID":128,"Name":"Makushin 1802","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) writes that Langsdorff reported strong earthquakes and fire-eruption of Makushin in 1802.  \r\n   Langsdorff (1812, translated by Victoria Joan Moessner, 1993) reports that \"Unalaska had heavy earthquakes almost every month until 1802, when finally there was an extraordinary earthquake, one never experienced there before, that destroyed several huts.  In 1806, they could no longer remember exactly in which month it had happened, so unremarkable is such an exceptional natural event for the inhabitants of that area.\r\n   \"Since then, the peak of the new island [Bogoslof?] has ceased to burn brightly.  The volcano on Unalaska, however, suddenly roared again mightily for the first time in many years.  It, as well as the volcano on Unimak and the new island, reciprocally burned and smoked.\"  This report does not state which year the \"burning and smoking\" occurred in.\r\n   Plummer (1898) translates Grewingk as \"Makushin active with flames and smoke.\"\r\n   Sapper (1917) is more hesitant about the eruption aspects of this event, and questions the \"fire-spewing\" notations.","StartYear":1802,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":160,"Name":"Okmok 1805","Description":"   Hantke (1951) wrote that there was \"an eruption on Umnak\" in 1805.  It is difficult to say if this eruption occurred and was from Okmok.  Grewingk (1850, translated 2003 by Fritz Jaensch) who compiled accounts of many travelers to the region during the time period 1760-1850, makes no mention of this eruption.  Langsdorff (1812),  who was present in the area from 1803 through 1807, also writes \"The active volcano on Umnak * * * has been totally still for a fairly long time\" - apparently discrediting the later report from Hantke.","StartYear":1805,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Okmok","ParentVolcano":"Okmok","VolcanoID":"ak206","ParentVolcanoID":"ak206"},{"ID":113,"Name":"Bogoslof 1806","Description":"   Dall (1884) writes: \"In 1806 fissures appeared, lined with crystals of sulphur.  According to Langsdorff, who saw it in this year, it did not exhibit any special activity, though steam and smoke arose more or less constantly.  In this year three baidarkas visited the island.  On the north side soft lava flowed into the sea, and it was too hot to approach closely; but on the southern end a landing was effected.  The peak was too sharp and rugged to be ascended, and the rock was very hot.  A piece of seal meat suspended in a crevice was thoroughly cooked in a short time.  There was no soil or fresh water.\"  Langsdorff reported the size of the island in 1806 as 10-15 versts in circumference, and 2,500 feet in elevation.\r\n   Grewingk (1850, translated 2003 by Fritz Jaensch) reports that Baranov reported the following in 1814 (possibly 1804?): \"On the first of June, 1814, a baidarka was launched to observe the phenomenon from a closer proximity.  When its occupants had approached to a distance of five versts, a violent current was observed between the pointed blind cliffs.  In spite of this it was possible to go ashore at a very low point, where sea lions had occupied the rocks in large numbers.  It appeared that the island consists entirely of precipices, covered with small rocks, which are continuously expelled from the crater.  They obscure the view and nearly cover the entire surface of the island.  Therefore it was impossible to make investigations on land.  It was instead decided to sail around it.  Nowhere could sweet water be found.  In the year 1815 (1805?) a second expedition was sent to the island. This time the island was found to be much lower in elevation than in the previous year.  The bad weather forced the people to remain there for six days.  A very strong current flowed continuously around the island.  The physiognomy of the island had changed completely.  There were ravines filled with masses of rock, which continuously collapsed, whereupon new precipices opened up.\"\r\n   In 1816 and 1817, Grewingk (1850, translated 2003 by Fritz Jaensch) writes that Eschscholtz reported no activity at Bogoslof.  Grewingk (1850, translated 2003 by Fritz Jaensch) also reports that Dr. Stein reported smoking at Bogoslof in 1820: \"And from the highest point of the mountain - which I call Kruzenstern Volcano - there arose, probably from the crater, columns of smoke (not fire).  From a crevice at the foot of the mountain, a spring sprouted up in an arch like a waterfall.  The entire island is a bare and barren rock; and only in a few places was there still snow, covered, it seemed, with volcanic ash.  On the sketch there appears on the right sides Cook's \"Ship Rock,\" which is much favored by the birds.  And the island St. J. Bogoslof presents the spectre of deep fissures and lava streams (ispeshchren), traversing its surface.  Its circumference amounted to 4 Italian miles (7 versts), and the elevation 500 ft., Engl., above sea level.\"\r\n   Veniaminov (1840, translated 1984) writes that \"At last in 1823 it noticeably ceased either to grow or to erode.  From the time of its appearance and until it ceased to increase in size, it was so hot that steam always rose from it and, at first, even the sea water around it was warm.\"\r\n   Newhall and Melson (1983) estimate the size of this lava dome to be about 10x10^6 cubic meters.","StartYear":1806,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1823,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Bogoslof","ParentVolcano":"Bogoslof","VolcanoID":"ak29","ParentVolcanoID":"ak29"},{"ID":65,"Name":"Kliuchef 1812","Description":"   Golovnin (translated in 1979 by Ella Wiswell, from the 1822 and 1819 versions) contains this information about Atka: \"* * * a very high volcano situated at that end of the island [northeastern].  Occasionally it causes dangerous earthquakes, and in 1812, when Vasiliev spent the winter here, it erupted and caused such strong earthquakes that the inhabitants were afraid of being buried in their yurtas (earthen huts).\"\r\n   Grewingk (1850, translated 2003 by Fritz Jaensch) also contains this report from Vasiliev, but attributes the eruption to Sarichef instead of Kliuchef or Korovin.  Dall (1870) reports that the earthquakes were \"most violent and terrified the inhabitants.\"  \r\n   Bank and others (1950) reports the following, which may pertain to this eruption: \"During the early eighteen hundreds Sarychef and Korovin volcanos [sic] on Atka commenced throwing off increasing amounts of ash, so that the priest decided that Korovinsky must be abandoned.  The seat of the Russian Church was transferred to Unalaska as was the trading center, and the villagers were moved to the site of the present village on Nazan Bay.  An interesting story concerning this forced move was told to me by a young Aleut hunchback, Johnny Prokopeuff, whose father had related it to him before he died.  I quote the story as we recorded it: 'Long time ago before peoples lived in this village Akta peoples live over at Old Harbor.  Was a big village with lots of barabaras and big Russian buildings.  There was man, Russian priest, name of Father Salamatoff who was kind to people.  He brought peoples from all around, Chugul, Kagalaska villages, Adak, to live at Old Harbor.  Another priest after Father Salamatoff died, I don't remember his name, told peoples they had to move village, said that mountain was going to come down and cover Old Harbor.  All the time at night the sky was red, and lost of little rocks (ash) in the air so that peoples sick.  Everyone moved over to this place and build village on Nazan Bay side.  Priest, he say that peoples safe here.  Mountain not come down on Old Harbor, but all the time at night lots of noise and red fire in the sky.  Big rocks roll down mountain.  Lots better on Nazan Bay, more fish.'\"  It is difficult to know which eruption this account is describing - Father Salamatoff died in 1864, so he was not already deceased with a different priest serving on Akta in 1812.  Korovin is reported as smoking and with fire in 1844, and this account may pertain to that eruption instead.\r\n   Wood and others (1990), Simkin and Siebert (1994), and  Miller and others (1998) attribute this eruption to Kluichef rather than Sarichef, due to a younger looking vent on Mt. Kluichef, but Golovnin's report of the volcano being on the \"northeastern side\" of the island argues that this event could be from Korovin instead.","StartYear":1812,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kliuchef","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak164","ParentVolcanoID":"ak17"},{"ID":331,"Name":"Augustine 1812","Description":"   From Kisslinger (1983), translating Doroshin (1870):  \"It was active in 1812, as was positively confirmed for me by a native of the village located on the opposite shore of Kenai Bay.  It wasn't possible to land canoes on the island while the wind was blowing, because the lava, which descends into the sea in a gentle slope, could at any time tear the skin of the canoe.\"\r\n  Waitt and Beget (2009) state \"This sparse and cryptic information suggests pyroclastic flows carrying boulder-sized pumice swept down the north and northeast flanks and into the sea. Such flows could voluminously reach down the short and steep run to water before debris avalanche added land to the coast in 1883 [see plate 1 in original text].\r\n   \"Yet we identify on Augustine Island no mappable deposit definitely of 1812. At the likely focus of pyroclastic flows, north and northeast, five later eruptions also focused debris - voluminously so in 1883, 1976, and 1986. The 1883 debris avalanche deeply buried that lower volcano flank in coarse rubble and established a new coast more than 2 km beyond the old one. There's no seeing what lies below these deposits. But in our interpretation of some measured sections [see plate 2 in original text] we speculate that a thin ash below the ash layer we identify with 1883 to be 1812 ash.\"","StartYear":1812,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":403,"Name":"Peulik 1814","Description":"   From Kisslinger (1983), translating Doroshin (1870): \"At the time of the Russian advent to these parts it emitted flame.  Around 1814 its summit collapsed with a rumble, covering the base with enormous boulders.  For about a week after this event, vapor rose from almost the entire surface of the mountain.\"  Miller (2004) qualifies this report, stating: \"Because Mount Peulik is separated from other prominent active volcanic edifices in the region [see fig. 1 in original text], these reports [of activity in 1814 and 1852] are credible and may represent the most recent eruptions at the center.\"","StartYear":1814,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Peulik","ParentVolcano":"Ugashik-Peulik","VolcanoID":"ak212","ParentVolcanoID":"ak295"},{"ID":187,"Name":"Pavlof 1817","Description":"   Jacob and Hauksson (1983) report normal explosions and lapilli falls from Pavlof in 1817.  Sapper (1917) reports that Medwinikowsky [Dutton] was smoking in 1817, and expresses some confusion about Medwinikowsky vs. Pavlof.  Sapper then reports that Kotzebue said that an eruption several years earlier threw out nut-sized basaltic bombs.","StartYear":1817,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":162,"Name":"Okmok 1817/3","Description":"   Grey (2003) has compiled and studied information about the 1817 Okmok eruption.  From her thesis: \"The first confirmed activity at Okmok was a large explosive eruption around 1817.  There is a discrepancy as to the exact date and duration of the eruption.  Veniaminov (1840, translated by Lydia T. Black and R.H. Geoghegan, 1984) maintains it was March 2, 1817; Postels (in Lutke, 1836) alleges it occurred on March 1, 1820.  Grewingk (1850, translated 2003 by Fritz Jaensch) favors Veniaminov's assertion and 1817 is the date most often cited.  However, Hantke (1951), who never visited the Aleutians, implies that Okmok was active during the entire four-year period and this is reflected in Simkin and Siebert (1994), though Hantke cites no specific references for his information.  Whenever this eruption occurred (or perhaps there were two more separate eruptions?), there is general agreement about what happened during the explosive phase.  During a storm with heavy SW winds, 'the range lying on the NE side of Umnak Island exploded * * * hurling great rocks for distances of up to 5 versts (~5 km)' (Veniaminov, 1840; Grewingk, 1850).  The strong earthquake accompanying the eruption frightened the inhabitants of Unalaska, 120 km ENE of Okmok, who reportedly woke in the morning to find up to a foot of ash on the ground in some places (Lutke, 1836; Veniaminov, 1840; Grewingk, 1850).  Iliuliuk Creek, which flows through Unalaska village, was reportedly so clogged with ash that it supported no fish for almost a year thereafter (Lutke, 1836; Grewingk, 1850).  Though these reports all mention heavy ash fall in Unalaska, today no such thick ash layer can be found to substantiate this claim.  It is quite possible that these eyewitness accounts overestimated the thickness of the deposit.  It is also likely that any ash that was deposited in Unalaska has long since been eroded by the wind and rain action notorious in the Aleutians.  Fieldworkers on Chuginadak Island in 2002 reported that the 2001 Cleveland ash fall on the island was approximately 20 cm thick up to 5 km from the vent, but still, no coherent ash layer can be found now, just some windblown pockets (J. Dehn, personal communication, 2003).\r\n   \"The Aleut village of Egorkovskoe (or Adus), located on Cape Tanak (formerly called Egorkovskoi) on the northernmost end of Umnak, was destroyed by the 1817 eruption while its inhabitants were hunting in the Pribilof Islands (Grewingk, 1850).  The villagers relocated to the Inanudak isthmus and in 1830 to the present site of Nikolski (Grewingk, 1850; Veniaminov, 1840).  Because of the distance from the eruption source within the caldera, it is unlikely that the explosion itself was responsible for depositing the large boulders found near Cape Tanak.  Wolfe and Beget (2002, and Wolfe, 2001) note a distinct absence of a thick enough tephra fall deposit at this site to bury a village.  Rather, it is more likely that the boulders and gravel were carried in a syneruptive ash-laden outburst flood from Okmok caldera, either by disruption of an intracaldera lake or by melting of snow during the eruption.  Radiocarbon date ranges for a 50-75 cm sand and gravel deposit found at Cape Tanak bracket the date of an outburst flood from the caldera between 1636-1951 AD from one soil sample, with a 55% probability between 1726-1813 AD, and between 1806-1931 AD for a second soil sample (Wolfe, 2001).  These dates correspond well with the date of this eruption and support this hypothesis.\r\n   \"It is possible that this explosive eruption originated from Cone E within the caldera because of the large, fresh pit crater in that cone that must have been formed by a forceful explosion quite recently.  Alternatively, field evidence suggests that the eruption may have been through the intracaldera lake, originating at the site of Cone B, which is located close to the breach in the caldera wall (J. Beget and T. Neal, personal communication, 2003).\"","StartYear":1817,"StartMonth":3,"StartDay":2,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1820,"EndMonth":3,"EndDay":1,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Okmok","ParentVolcano":"Okmok","VolcanoID":"ak206","ParentVolcanoID":"ak206"},{"ID":98,"Name":"Yunaska 1817/4","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) writes that Choris (Voyage pittoresque autour du monde, avec des portraits de sauvages d'Amerique, D'Asie, d'Afrique, et des iles du Grand ocean; des paysages, des vues maritimes, et plusieurs objets d'histoire naturelle; accompagne de descriptions par m. le baron Cuvier, et m. A. de Chamisso, et d'observations sur les cranes humains, par m. le docteur Gall, 1822, in French) reported smoking from Yunaska at the beginning of  April, 1817.","StartYear":1817,"StartMonth":4,"StartDay":7,"StartTime":null,"StartQualifier":7,"StartQualifierUnit":"Days","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Yunaska","ParentVolcano":"Yunaska","VolcanoID":"ak329","ParentVolcanoID":"ak329"},{"ID":572,"Name":"Great Sitkin 1818/7","Description":"   Golovnin reports that on June 28, 1818, he could see a high mountain on [Great] Sitkin emitting smoke.  It is uncertain if this reference to \"smoke\" is evidence of an actual volcanic eruption, as Great Sitkin also has prominent fumaroles that are often steaming.","StartYear":1818,"StartMonth":7,"StartDay":28,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":129,"Name":"Makushin 1818/8","Description":"   Veniaminov (1840, translated in 1984 by Lydia Black and R. H. Geoghegan) wrote about Makushin: \"No one remembers [this mountain] ever emitting flame, but from time to time it produces subterranean thunders, as has happened in August 1818.  At that time, the mountain thundered so strongly that a slight [earth] tremor was perceived and those living at Unalaska [settlement] believed that the nearby island of Amaxnax was breaking apart.\"\r\n   Grewingk (1850, translated 2003 by Fritz Jaensch) writes that Langsdorff and Krusenstern also report Makushin to have erupted strongly with flames in 1818.  However, Grewingk (1850, translated 2003 by Fritz Jaensch) adds a footnote stating that this report \"is an error.  It was probably meant to mean, 'in smoke.'  Characteristic of the Makushin Volcano is that it does not erupt in flames, this according to all other reports, including Cook's (from 1778).\"","StartYear":1818,"StartMonth":8,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":397,"Name":"Wrangell 1819","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) writes that Klimovskii and Wrangell report that Wrangell volcano was discovered in 1819, \"active, and several earthquakes annually.\"","StartYear":1819,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Wrangell","ParentVolcano":"Wrangell","VolcanoID":"ak326","ParentVolcanoID":"ak326"},{"ID":435,"Name":"Redoubt 1819","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch): \"Since [Redoubt] became known in 1819, it has been smoking (Wrangell).\"  Most subsequent compilers do not consider this event to be a volcanic eruption.","StartYear":1819,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Redoubt","ParentVolcano":"Redoubt","VolcanoID":"ak231","ParentVolcanoID":"ak231"},{"ID":273,"Name":"Westdahl 1820","Description":"   From Miller and others (1998): \"Coats (1950) attributed four eruptions in the late eighteenth century and early nineteenth century to Pogromni volcano.  Based on recent observations from aircraft, however, Pogromni does not appear to have been active in historical time.  The eruptions should probably be assigned to Westdahl.\"\r\n   The eruption of 1820 is a little more confusing, as reports are unclear as to whether the event occurred on Unimak Island (containing the volcanoes of Westdahl, Pogromni, Fisher Caldera, Shishaldin, Isanotski, and Roundtop) or Umnak Island (containing the volcanoes Okmok, Recheshnoi, and Vsevidof).  Modern compilers have attributed this event to Westdahl.\r\n   Soloviev and Go (1972) report: \"1820, March 1 or the night of 2-3.  A powerful volcanic eruption occurred on the northern tip of Umnak Island.  The ashes spread as far as Unalaska and Unimak Islands.  The eruption was accompanied by a strong earthquake.  'At dawn, it was observed that the sea had become more agitated' (Perrey, 1865 [in French]).\"  Lander (1996) attributes this eruption to Pogromni, which is on southwest Unimak Island.  Okmok Volcano is on the northeast of Umnak Island.\r\n   Lander (1996) writes \"1820, March 1-2.  Due to a strong eruption of Pogromni Volcano on the northern tip of Umnak Island [typographical error?  Pogromni and Westdahl are on the southwestern side of Unimak Island], ashes injected into the air were observed as far away as Unalaska and Unimak [Another error?  Westdahl and Pogromni are on Unimak] Islands.  There was a strong earthquake on the night of March 1.  The sea was observed to have became highly disturbed by dawn (Soloviev and Go, 1975: in Russian).  Mushketov and Orlov (1893, p. 207-208: in Russian) describe the eruption has having taken place on February 19-20 (March 1-2 in Gregorian date) and another account dated March 1 referring to ash fall clouding the sea.  Although the highly disturbed sea is suggestive of a tsunami, there is no specific mention of waves.\"\r\n   Mushketov and Orlov (1893, translated in 1994 by Katherine Arndt) wrote: \"In 1820, on 19 February (Old Style) (in the night on the 20th), in a severe SE wind, on certain islands of the Aleutian Archipelago there were felt strong tremblings of the earth with a subterranean rumble. Immediately after, the air, it seemed, caught fire and clouds of ash and sand began to fall during the whole night. With the approach of day the wind changed, the volcanic matter stopped falling, but the sea was highly agitated. At the same time as these phenomena occurred on Unalaska, the volcano of Urimak [sic] Island, located 197 kilometers from Unalaska, began to produce eruptions which continued until August. (According to Postels, the active volcano was located on the north end of Umnak Island.) People who set out to look for the crater, due to the stinking steams tha thad spread for a verst, could not approach it and were convinced only that the island had increased in size and that the sea had rushed back for a considerable distance. Volcanic products erupted in such quantity that Urimak Island was covered with them for a radius of three miles around the crater. Postels describes these phenomena in the following manner: on 1 March on the north end of Umnak Island there occurred an eruption in which the ash reached Unalaska and Unimak. A strong earthquake, accompanied by a severe storm from the SE, plunged the inhabitants of Unalaska into terror. With the rising of the sun they saw that in certain places the earth was covered with ash more than a foot deep; the springs were choked with it, [and] the sea became cloudy, so that for a whole year fish were not seen in it and even whales appeared more rarely than usual. Not far from the site of eruption the Aleuts found amber in the loosened earth which covered the cliff that is washed by the lake.\" Mushketov and Orlov cite Malte Brun, Nouv. annales des voyages, XV, p. 131; Arago, Ann. de chimie et de phys., XXI, p. 396; and Postels, Voyage autour du monde, III, p. 24.\"\r\n   Coats (1950) reports a minor explosive eruption and Powers (1958) reports an ash eruption.","StartYear":1820,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Westdahl","ParentVolcano":"Westdahl","VolcanoID":"ak322","ParentVolcanoID":"ak322"},{"ID":99,"Name":"Yunaska 1824","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) writes that Litke reported \"renewed eruption,\" an \"enormous eruption after long dormancy.\" in 1824.  The English translation of Litke \"A voyage around the world, 1826-1829) does not contain reference to this event.  However, the English translation does not cover all of Litke's publications for this voyage, which he published in both Russian and French.(Dall (1870) writes that a \"major eruption took place on Yunaska.\"  Petroff (1884) writes that \"[Y]unaska in violent eruption after a long repose.\"  Becker (1898) reports this eruption as a \"great eruption.\"   Powers (1958) reports this eruption as an ash eruption.)\r\n   Veniaminov (as translated by Black and Geoghegan, 1984) writes that in 1825 \"The peak on Iunaska Island, which burned in antiquity but then went out, also in time immemorial, exploded at the beginning of 1825 with a thunderous roar heard on Umnak.  Its summit collapsed with an accompanying expulsion of burned rocks (gorely kamen'ia - pumice) which floated on the sea even until June.  Since then it has smoked incessantly.\"\r\n   Sapper (1917) reports that Perrey said the eruption continued \"until the end of June, with stones thrown out\" leaving which year or years the eruption occurred in still uncertain.\r\n   Perhaps this description refers to this eruption from Yunaska; perhaps the eruption occurred around the end of 1824 and beginning of 1825, explaining the discrepancy in years.  Khlebnikov (translated in 1994) seems to support this theory, as he relays what Davydov reported: \"In the winter of 1824-1825 a mountain erupted on Iunaska Island.  It was not very high and did not have a sharp peak.  Toion Ivan Pan'kov, who was sent to this island with a party of Aleuts to hunt sea otters in the spring of 1825, found the appearance of the island completely altered.  All the shores were covered with igneous rock, while thick smoke streamed from the mountain, which, when the nights were dark, glowed like fires.  In June 1827, passing within sight of this island, we noticed smoke coming out of a mountain on the island.\"","StartYear":1824,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1825,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Yunaska","ParentVolcano":"Yunaska","VolcanoID":"ak329","ParentVolcanoID":"ak329"},{"ID":163,"Name":"Okmok 1824","Description":"   From Grey (2003): \"According to Grewingk (1850, translated 2003 by Fritz Jaensch), Lutke reported an eruption on the northeast end of Umnak Island, during which a 'mountain ridge opened up' in 1824 and was still 'smoking' in 1830.  He also says that Postels (in Lutke, 1836) erroneously reported the activity as stretching along the northwest coast, but does not mention on what basis this presumption of error is made - perhaps the eruption was merely viewed from off the NW coast and appeared nearer than it was.  I interpret these two reports as describing a linear (fissure) eruption and postulate that it may have taken place along the chain of small vents within the caldera that extends west from Cone B.  This assumes fire fountains reaching above the caldera rim (500 m or more in height).\"  \r\n   Grey (2003) explains that fire fountains this high are unlikely, and then continues as follows: \"Perhaps the observer saw the red glow of the eruption reflected on the underside of a low cloud deck.  The relative freshness of the deposits from this arcuate fissure supports a historic time frame.  There is also a young lava flow from Cone B that is so fresh it was originally mistaken for 1958 lava during field work in 2000 and could have been erupted in this time frame as well.\"\r\n   Powers (1958) also states that he believes a lava flow likely occurred during this eruption.","StartYear":1824,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1830,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Okmok","ParentVolcano":"Okmok","VolcanoID":"ak206","ParentVolcanoID":"ak206"},{"ID":345,"Name":"Shishaldin 1824","Description":"   From Veniaminov (1840, translated by Lydia T. Black and R.H. Geoghegan, 1984), writing of Shishaldin Volcano: \"[T]oward the end of 1824 and early in 1825, up to the 10th of March, that is, until the explosion of the Issanakhskii Range, it was burning with a fierce flame.\"  Although Veniaminov writes that the eruption of the 10th of March was from the \"northeast range of Unimak\" and that \"Shishaldinskaia sopka, located not far from this range on the west, emitted flame before this time, but after the explosion began just to smoke,\" suggesting that the March 10, 1825 eruption was not from Shishaldin, and perhaps from Isanotski, Alaska Volcano Observatory geologists now believe that this eruption did come from Shishaldin.  Alaska Volcano Observatory geologists flying over Isantoski in 1987, 1988, and 1989 failed to find any apparently Holocene vents on Isanotski, and saw only glacially polished rocks.  Field investigations of Shishaldin, however, reveal numerous Holocene vents, including a very large flank feature called \"The Blister\" that has melted through the modern ice cover of Shishaldin, and which could be the vent for eruptions during the 1800s.  In addition, several streams draining from Shishaldin look capable of carrying large amounts of sediment to the sea (as described by Veniaminov for the March 10 eruption), but all of the streams draining Isanotski are heavily vegetated, suggesting that they did not carry large amount of sediment within the last few hundred years (Chris Nye, personal commun., 2004).  Finch (1934) and  Grewingk (1850, translated 2003 by Fritz Jaensch) also believe that the March 10 eruption occurred at Shishaldin.\r\n   Veniaminov's description of the March 10, 1825 eruption is as follows: \"On March 10, 1825, after a loud subterranean thunder very similar to a cannonade, which lasted almost the whole day and was audible on Unalashka, Akun, and the tip of Aliaksa, in the middle of the day, the northeast range of Unimak exploded in five or more places and a great quantity of black ashes which covered the whole end of Aliaksa for several inches.  At nearby Aliaksa, and especially at Morzhevoskoi settlement, it was dark for 3 or 4 hours.  On this occasion the ice and snow, lying on the range melted and for several days flowed in a dreadful river, 5 to 10 versts wide.  These waters poured over the eastern side of the island in such a quantity that the nearby sea remained muddy until late autumn.\"\r\n   From  Grewingk (1850, translated 2003 by Fritz Jaensch): \"In the year 1824 and early in 1825 the eruptions of Shishaldin Volcano were especially violent (cf. Lutke's p.n., or Berghaus: Geography and Ethnography, II, p. 724).  And toward the middle of the month of March, a low ridge NE of this mountain split open in five or six places after a terrible subterranean detonation that was heard on Unalaska Island and on Alaska.  Flames and black ashes were expelled, which covered the Alaska Peninsula all the way to Pavlof Bay.  At high noon it was dark as night even in Morzhovoi Village, 10 German miles away.  At the same time a flash-flood [jokulhlaup] descended from the mountain, down the south side of the island, covering a section of land more than two German miles long, as it catapulted pumice stones along with it.  But the flood did not last long.  Even the waters of the ocean were murky far into the autumn season.  Since that event the volcano has burned less strongly.  The ridge, through which the subterranean powers released their pressure, continues to smoke constantly; likewise a small cone, which began to rise from the middle of the ridge.\"","StartYear":1824,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1825,"EndMonth":3,"EndDay":10,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":188,"Name":"Pavlof 1825","Description":"   Sapper (1917) reports that in 1825 the volcano \"reopened itself\" and smoked continuously for a long time.  Hantke (1955) reports that this eruption was from the southern crater.","StartYear":1825,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":449,"Name":"Isanotski 1825/3","Description":"   Several historical eruptions have been attributed to Isanotski, most notably the explosive March 10, 1825 eruption.  However, according to Alaska Volcano Observatory geologists, Isanotski shows no evidence of having any possibly Holocene vents.  Alaska Volcano Observatory geologists flying over Isanotski in 1997, 1998, and 1999 failed to find any apparently Holocene vents on Isanotski, and saw only glacially polished rocks.  Geologists from AVO suggest that all historical eruptions of Isanotski instead be attributed to Shishaldin.  Field investigations of Shishaldin reveal numerous Holocene vents, including a very large flank feature called \"The Blister\" that has melted through the modern ice cover of Shishaldin, and which could be the vent for eruptions during the 1800s.  In addition, several streams draining from Shishaldin look capable of carrying large amounts of sediment to the sea (as described by Veniaminov for the March 10, 1825 eruption), but all of the streams draining Isanotski are heavily vegetated, suggesting that they did not carry large amount of sediment within the last few hundred years (Chris Nye, personal commun., 2004).\r\n   Veniaminov (1840) is very clear that the March 10, 1825 eruption is from Shishaldin, and not Isanotski, and Grewingk (1850) reports \"Volcanic eruptions on Unimak's east side in the Isannak Range on the tenth of March.\"  Petroff (1884) also clearly states this eruption as being from Shishaldin, but Coats (1950) reports Isantoski and Shishaldin as erupting in 1825.","StartYear":1825,"StartMonth":3,"StartDay":10,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Isanotski","ParentVolcano":"Isanotski","VolcanoID":"ak135","ParentVolcanoID":"ak135"},{"ID":130,"Name":"Makushin 1826/6","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) wrote that Postels reported two strong earthquakes in June, 1826, and Makushin erupted in flames.  Grewingk (1850, translated 2003 by Fritz Jaensch) adds a footnote stating that this report \"is an error.  It was probably meant to mean, 'in smoke.'  Characteristic of the Makushin Volcano is that it does not erupt in flames, this according to all other reports, including Cook's (from 1778).\"\r\n   Litke (1835, translated in 1987) reported that Makushin was smoking on September 1, 1828.","StartYear":1826,"StartMonth":6,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1828,"EndMonth":9,"EndDay":1,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":346,"Name":"Shishaldin 1826/10","Description":"   Shishaldin Volcano appears to have been in intermittent eruption from October, 1826, until 1831.\r\n   This description by Litke (translated in 1987 by R.A. Pierce) perhaps refers to Shishaldin: \"From October 1826 until January 1827 there had been almost uninterrupted eruptions of ash of almost unparalleled violence at a location where no one had seen a crater before.  The ash, pushed first one way and then another by the wind, had covered all the surrounding countryside and even the quite distant islands of Unalaska and Unga with ash, thus causing considerable damage.  Similar movement, although not as widespread, had occurred before the eruption and had been going on since.  Not long before our arrival at Unalashka a thunder like roar, a well known signal, announced that Unimak was by no means sleeping.\"\r\n   Litke (translated in 1987 by R.A. Pierce) also writes: \"On September 1st [1827], a superb morning revealed to us the magnificent panorama which surrounded us on all sides.  East northeast, at a distance of sixty-five miles, we could see the Island of Unimak, with its enormous volcanoes.  One of these, Shishaldin, whose form resembles that of a regular cone, appeared at this distance to be completely isolated.  A whitish smoke rose up from its summit.\"\r\n   Veniaminov (1840, translated by Lydia T. Black and R.H. Geoghegan, 1984) writes about Shishaldin: \"Later, and until March 1827, it was only smoking.  Afterwards, again up to 1829, it threw out strong flame then, from that time, until the fall of 1830, it changed in an extraordinary way.  In November and December, while enveloped in fog, it thundered violently and, when the fog lifted, the appearance of the mountain had been wholly altered.  On the north side, from the very crater downward, three clefts of relatively large size had formed, looking as if filled with red-hot iron.  Appalling flames were emitted from its crater, subterranean thunder was heard from time to time, and there were perceptible tremors.  The eternal snow and ice, lying on its summit on the N, W, and S sides of its tip and from the peak to about the midheight, melted completely.  This appearance it retained until March, when the clefts one after another closed and in the fall it was covered with new snow.  Since then it has merely smoked.  During all this period, there were scarcely any eruptions, except that on the 20th of April some volcanic ash fell on the snow.  The foot of this volcano toward the NE was rather hot and, it was said, trembled perceptibly.\"\r\n      Khlebnikov (translated in 1994 by Marina Ramsay) writes that in November and December 1830, \"Shishaldin rumbled violently, and after the mist cleared they saw that almost all the snow which had covered it for many years had melted and it appeared black.  At the same time to the north, south and west three enormous openings appeared from top to bottom and began to disgorge terrible flames into the air.  These flames, which were always visible from the north on a clear night, three times in a minute broke out in explosions, and after three or four such eruptions only sparks were seen. They say that at its foot to the northeast it was hot.  Then, in March 1831 all the openings closed except one remaining to the north-northeast, going from the crater itself no less than a fifth of the entire mountain in length, and in width about a seventh part long.  It was like hot iron and never changed its appearance.  However, no eruptions from the mountains were observed.  These remarks Khlebnikov took from a letter to him from I.E. Veniaminov dated 13 August 1831.\"\r\n   In a footnote, Veniaminov (1840, translated by Lydia T. Black and R.H. Geoghegan, 1984) further writes: \"During my [visit] on March 6 and 7, 1831, the volcano was fully visible twice.  From its crater lying to the NE, every ten or fifteen issued fire and sparks, not every time with the same force but sometimes more flames and less sparks or vice versa.  Downward and to the NE from the crater one could see a crevice, in length exceeding more than 1/5 of the mountain's height, its width was about 1/8 of its length.  At night the crevice seemed like red hot iron, not changing in the least.  So it must be considered that this crevice was not the continuation of the crater but a crust or wall at which the flame was active.  Bridging this crevice, several dark, narrow necks were visible.  The appearance of the whole volcano was most sad and horrifying - black, snowless, pitted to mid-height with deep longitudinal ravines and covered with protruding rocks, it stood [like] a frightful bonfire, surrounded by glistening white mountains.  Only on its E side was there snow, extending almost to its very summit.  This signified that the crust on this side was thicker than on the other sides.\"\r\n    Grewingk (1850, translated 2003 by Fritz Jaensch) summarizes the November and December 1830 activity as follows: \"Shishaldin roared terribly out of the fog which enveloped it.  After the fog had lifted, everyone was surprised about the black color which the mountain had taken on.  The snow, which had always covered it, had disappeared; and long fissures, which expelled frightful flames, appeared on three sides simultaneously: on the north, west, and south side.  The northern side was constantly aflame.  The fire erupted in spurts three times per minute and after every third or fourth normal emission there comes a stronger flame accompanied by sparks.  In March of 1831, two fissures closed up.  Only the northern one remained, which from base to top extended no less than one-fifth of the way up the entire elevation of the mountain.  Its width is about one-seventh of its length.  It looks like glowing iron, and it never changes its appearance.  On the northeastern base, too, the mountain is supposed to be on fire.  After these eruptions, the natives believed they noticed a diminishing of the earthquakes.  It is reported that blueberry bushes did appear in the aftermath of the falling of the fertile ashes near Pogromnoi village.  Formerly they had not been there.  In the aftermath of the eruption of 1827, the fish and shellfish near the same village became more rare.  The former drifted about, dead on the ocean, and were washed ashore.\"","StartYear":1826,"StartMonth":10,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1831,"EndMonth":3,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":407,"Name":"Fisher 1826/10","Description":"   Khlebnikov (translated in 1994) writes of a volcano that is possibly Fisher caldera: \"On 12 October 1826 the crest of another mountain [not Shishaldin or Isanotski] on the southwest side of the island [Unimak] was ruptured with horrible thunder-like noise, throwing out a lot of ash which was carried by the then blowing east wind and dropped over various places on Unalashka Island.  The residents of Unimak Island sat in their yurts for ten days with lights, because it was impossible to go outside because of the blowing ash, which, entering the eyes and nose, caused an unbearable headache.  During all this time, no daylight was visible.  The condition of the atmosphere at that time would have given an amateur observer an understanding of atoms.\"\r\n   Veniaminov (1840, translated by Lydia T. Black and R.H. Geoghegan, 1984) also writes: \"On October 11, 1826, with a dull noise, it [the low peak in the interior of Unimak Island] burst, emitting strong flames and a large quantity of ash of whitish color, which covered part of Aliaksa, Sannakh, and the islands closest to the latter, and was carried even to Unga.  (This same ash caused the destruction of the wild pigs on Chernoburyi Island and the decrease of the caribou.)  Since that time, the scattered large, extremely hot rocks, which lie about in heaps, have emitted incessant smoke.  Around this peak burning sulphur may be found.  All streams and swamps about this area are so hot that they steam constantly.\"\r\n   Subsequent compilers have used Veniaminov's October 11, 1826 date as the start of the eruption rather than Khlebnikov's October 12 date.\r\n   Stelling and others (2005) state: \"The most likely deposit related to this eruption is a thin, fine-grained, black scoria within the vegetation mat distributed across the central portion of the caldera.  The fresh apperance of the summit of Mt. Finch and the limited dispersal of the scoria layer suggest that the eruption emanated from this cone.\"","StartYear":1826,"StartMonth":10,"StartDay":11,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1827,"EndMonth":1,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Fisher","ParentVolcano":"Fisher","VolcanoID":"ak100","ParentVolcanoID":"ak100"},{"ID":37,"Name":"Kanaga 1827","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) writes that Lutke reported Kanaga smoking in 1827.  It is uncertain if this \"smoke\" was simply fumarolic activity from Kanaga's active fumaroles or if it was from an actual eruption.","StartYear":1827,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kanaga","ParentVolcano":"Kanaga","VolcanoID":"ak144","ParentVolcanoID":"ak144"},{"ID":62,"Name":"Kasatochi 1827","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) writes that Koniuji was smoking in 1827.\r\nCoats (1950) attributes historical eruptions of Koniuji to Kasatochi instead, because Koniuji is \"deeply eroded\" and \"does not appear to have been active in Recent time.\"","StartYear":1827,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kasatochi","ParentVolcano":"Kasatochi","VolcanoID":"ak146","ParentVolcanoID":"ak146"},{"ID":81,"Name":"Seguam 1827","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) states that Seguam was reported smoking in 1827 by Lutke.","StartYear":1827,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Seguam","ParentVolcano":"Seguam","VolcanoID":"ak246","ParentVolcanoID":"ak246"},{"ID":274,"Name":"Westdahl 1827/3","Description":"   From Miller and others (1998): \"Coats (1950) attributed four eruptions in the late eighteenth century and early nineteenth century to Pogromni volcano.  Based on recent observations from aircraft, however, Pogromni does not appear to have been active in historical time.  The eruptions should probably be assigned to Westdahl.\"\r\n    Grewingk (1850, translated 2003 by Fritz Jaensch) reports that Isenbeck said that Pogromnaia was belching fire in 1827, and \"Lastly, on the southern side of Unimak, on the west side of Tugamak Gulf [Unimak Bight], the location of which is not accurately fixed, but probably not far from Pogromnoi Volcano, there, in September of 1827, according to the log of the corvette Moller, a 'lava brulante' was observed, meaning most likely a not-yet-cooled lava stream.  Dr. Isenbeck reports (oral report) that during the passage through the Strait of Unimak, a fiery column constantly ascended from the volcano closest to the coast.  This was probably Pogromnoi Volcano, although Veniaminov's indications, according to which the Shishaldin erupted at the same time, speak against it.\"\r\n    Powers (1958) reports an ash eruption.","StartYear":1827,"StartMonth":3,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1829,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Westdahl","ParentVolcano":"Westdahl","VolcanoID":"ak322","ParentVolcanoID":"ak322"},{"ID":9,"Name":"Little Sitkin 1828","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch): \"1828, Little Sitkin, Akun, Akutan, Tanakh-Angunakh, Atka, Koniushi, Gareloi, and Unimak (Shishaldin) smoking.\"\r\n   Dall (1870), summarizing Grewingk: \"Little Sitkin, Akhun, Akutan, Tanak-Angunakh, Atka, Koniushi, Goreloi, and Shishaldin smoked.  The disturbances continued for two years.\"  Dall (1870) reads as if the smoking on all of these islands continued for two years, but Grewingk (1850, translated 2003 by Fritz Jaensch) is more clear -- the next entry, for 1829 reads \"On Unimak, Shishaldin smokes until fall of 1830.\"  Presumably, the other volcanoes listed were only smoking during 1828.","StartYear":1828,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Little Sitkin","ParentVolcano":"Little Sitkin","VolcanoID":"ak182","ParentVolcanoID":"ak182"},{"ID":21,"Name":"Gareloi 1828","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch): Gareloi smoking during 1828.  Grewingk (1850, translated 2003 by Fritz Jaensch) also states  that Gareloi was smoking during 1829.  Miller and others (1998) combined these citations to make one eruption from 1828 until 1829.  Simkin and Siebert (1994) reference only the 1829 eruption.","StartYear":1828,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1829,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Gareloi","ParentVolcano":"Gareloi","VolcanoID":"ak106","ParentVolcanoID":"ak106"},{"ID":63,"Name":"Kasatochi 1828","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) writes that Koniuji was smoking in 1828.\r\nCoats (1950) attributes historical eruptions of Koniuji to Kasatochi instead, because Koniuji is \"deeply eroded\" and \"does not appear to have been active in Recent time.\"","StartYear":1828,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kasatochi","ParentVolcano":"Kasatochi","VolcanoID":"ak146","ParentVolcanoID":"ak146"},{"ID":228,"Name":"Akutan 1828","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) writes that Postels [Russian naturalist aboard the Seniavin] reported Akutan smoking and having hot springs in 1828.  Dall (1870) writes: \"Little Sitkin, Akun, Akutan, Tanak-Angunakh, Atka, Koniushi, Goreloi, and Shishaldin smoked.  The same disturbances continued for two years.\"  This sentence appears to say that all of these volcanoes smoked for two years, which was probably not the case, according to the earlier statements found in Grewingk, which states that Shishaldin smoked for multiple years and doesn't say that Akutan smoked beyond 1828.  However, some successive compilers since Dall, including Plummer (1898) and Jacob and Hauksson (1983), state that Akutan was in eruption for two years.","StartYear":1828,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":328,"Name":"Carlisle 1828","Description":"   Documentation of early eruptions in the Islands of the Four Mountains region is scanty and uncertain.  Previous compilers (Simkin and Siebert, 1994; Miller and others, 1998) have assigned this eruption to Carlisle.  Based on descriptive information found in Veniaminov (1840, translated by Lydia T. Black and R.H. Geoghegan, 1984) and  Grewingk (1850, translated 2003 by Fritz Jaensch), this eruption has been reassigned to Cleveland.  Please refer to Cleveland's eruptive history for information about this event.","StartYear":1828,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Carlisle","ParentVolcano":"Carlisle","VolcanoID":"ak40","ParentVolcanoID":"ak40"},{"ID":283,"Name":"Cleveland 1828","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) reports that Litke reported that in 1828, Tanak-Angunak had an active volcano, with hot springs at its base.  The English translation of Litke \"A voyage around the world, 1826-1829) does not contain reference to this event.  However, the English translation does not cover all of Litke's publications for this voyage, which he published in both Russian and French. There is also some confusion as to whether \"Tanak-Angunach\" refers to Carlisle volcano or Mount Cleveland.  From Miller and others (1998): \"Various names were applied to Carlisle on early hydrographic charts, including Uliaga, Kigalgin and variants thereof; it was also sometimes referred to along with the western half of Chuginadak Island, as Tanak-Angunak.  It is thus possible that some of the activity ascribed to Carlisle should be attributed to Uliaga or Mount Cleveland (Coats, 1950).\"\r\n      In support of this particular \"Tanak-Angunak\" referring to Chuginadak Island (the island Cleveland Volcano is part of) is Grewingk's description of Tanak-Angunak:  \"* * * oblong with a steep south side.  An active volcano rises on its western side.  According to an Aleutian legend it once formed an island by itself.  But the dividing strait was filled in when a mountain collapsed.  At the foot of this mountain there is a spring so hot that it can be used to cook in.\" This description fits with the two part appearance of Chuginadak Island, and does not match the single-circle shape of Carlisle Island.","StartYear":1828,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":512,"Name":"Gilbert 1828","Description":"   Grewingk (1850) reports that Postels and Veniaminov reported hot springs on the northern part of Akun Island (Mt. Gilbert is also on the northern part of Akun Island) but that no volcanic phenomena were observed until Postels reported periodic smoke columns in 1828.","StartYear":1828,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Gilbert","ParentVolcano":"Gilbert","VolcanoID":"ak108","ParentVolcanoID":"ak108"},{"ID":32,"Name":"Tanaga 1829","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) reports: Tanaga smoking during 1829.","StartYear":1829,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Tanaga","ParentVolcano":"Tanaga","VolcanoID":"ak280","ParentVolcanoID":"ak280"},{"ID":38,"Name":"Kanaga 1829","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) writes that Kanaga was smoking in 1829.","StartYear":1829,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kanaga","ParentVolcano":"Kanaga","VolcanoID":"ak144","ParentVolcanoID":"ak144"},{"ID":49,"Name":"Great Sitkin 1829","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) reported that Ingenstrom reported Great Sitkin as \"covered with snow and smoking (?)\" in 1829.  Other, more recent compilations list this event as possibly starting in 1828, or a separate event occurring in 1828.","StartYear":1829,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":66,"Name":"Korovin 1829","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) writes that Ingenstrom reported Korovin smoking in 1829 and 1830.  Petroff (1884) reports Korovin as \"in eruption and smoking\" during 1829 and 1830.  However, because Petroff (1884) is an incomplete translation of Grewingk (1850) the smoke-only reports are probably more accurate.\r\n   Additionally, the following account written by Bank and others (1950) may pertain to this eruption: \"During the early eighteen hundreds Sarychef and Korovin volcanos [sic] on Atka commenced throwing off increasing amounts of ash, so that the priest decided that Korovinsky must be abandoned.  The seat of the Russian Church was transferred to Unalaska as was the trading center, and the villagers were moved to the site of the present village on Nazan Bay.  An interesting story concerning this forced move was told to me by a young Aleut hunchback, Johnny Prokopeuff, whose father had related it to him before he died.  I quote the story as we recorded it: 'Long time ago before peoples lived in this village Akta peoples live over at Old Harbor.  Was a big village with lots of barabaras and big Russian buildings.  There was man, Russian priest, name of Father Salamatoff who was kind to people.  He brought peoples from all around, Chugul, Kagalaska villages, Adak, to live at Old Harbor.  Another priest after Father Salamatoff died, I don't remember his name, told peoples they had to move village, said that mountain was going to come down and cover Old Harbor.  All the time at night the sky was red, and lost of little rocks (ash) in the air so that peoples sick.  Everyone moved over to this place and build village on Nazan Bay side.  Priest, he say that peoples safe here.  Mountain not come down on Old Harbor, but all the time at night lots of noise and red fire in the sky.  Big rocks roll down mountain.  Lots better on Nazan Bay, more fish.'\"  It is difficult to know which eruption this account is describing - Father Salamatoff died in 1864, and this account may somehow refer to the 1812 eruption of Kliuchef, the 1829-1830 eruption of Korovin, or another eruption entirely.","StartYear":1829,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1830,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Korovin","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak171","ParentVolcanoID":"ak17"},{"ID":14,"Name":"Mount Young 1830","Description":"   From Miller and others (1998): \"Records of volcanism on Semisopochnoi Island are scant; historical eruptions could have involved the small Lakeshore Cone and Sugarloaf cone in addition to Mount Cerberus [Mount Young].  However, since at least one of the early reports specified that the activity noted was in the center of the island, and Mount Cerberus is the least eroded of the recent cones, it is believed to have been the source of most recorded events (Coats, 1950; 1959).\"\r\n   Grewingk (1850, translated 2003 by Fritz Jaensch), writes that Lutke reported Semisopochnoi smoking in 1830.","StartYear":1830,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mount Young","ParentVolcano":"Semisopochnoi","VolcanoID":"ak44","ParentVolcanoID":"ak248"},{"ID":100,"Name":"Yunaska 1830","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch): writes that there was an expulsion of ashes from Yunaska in 1830.  \r\n   Mushketov and Orlov (1893, translated in 1994 by Katharine Arndt) wrote: \"In the same year [1830] an earthquake at the volcano Yunaka [sic; Yunaska?] and an eruption of flame and ash, in which there appeared a torrent which formed from melted snow or from rain and, like the sea water, was colored black.\" Mushketov and Orlov cite Grewingk (1850) and Perrey (1866).","StartYear":1830,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Yunaska","ParentVolcano":"Yunaska","VolcanoID":"ak329","ParentVolcanoID":"ak329"},{"ID":108,"Name":"Vsevidof 1830","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) cites Veniaminov and writes that in 1830 there was renewed activity of a volcanic cone on the SW end of Umnak Island -- perhaps Recheshnoi.  Sapper (1917) reports the date of this event as May 30, 1790, and as at Vsevidof.  Coats (1950) also notes that Recheshnoi is deeply eroded and that this eruption probably took place at Vsevidof instead.  The 1984 English translation of Veniaminov does not appear to contain reference to this event - the only notation of an eruption in 1830 is of a \"low peak in the interior of Unimak Island\" [perhaps Westdahl?]: \"In August, 1830, the summit of this peak exploded again, but without any other special phenomena.\"","StartYear":1830,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Vsevidof","ParentVolcano":"Vsevidof","VolcanoID":"ak307","ParentVolcanoID":"ak307"},{"ID":278,"Name":"Westdahl 1830","Description":"   From Miller and others (1998): \"Coats (1950) attributed four eruptions in the late eighteenth century and early nineteenth century to Pogromni volcano.  Based on recent observations from aircraft, however, Pogromni does not appear to have been active in historical time.  The eruptions should probably be assigned to Westdahl.\"\r\n   Petroff (1884) reports an eruption in autumn of 1830, but  Grewingk (1850, translated 2003 by Fritz Jaensch) suggests the eruption is from Shishaldin.  Becker (1898) lists an 1830 eruption with ashes.","StartYear":1830,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Westdahl","ParentVolcano":"Westdahl","VolcanoID":"ak322","ParentVolcanoID":"ak322"},{"ID":304,"Name":"Veniaminof 1830","Description":"    Grewingk (1850, translated 2003 by Fritz Jaensch) writes that Mount Veniaminof was smoking during 1830-40, as reported by Father Veniaminov.  Kisslinger (1983), translating Doroshin (1870): \"On August 4 [August 16, Gregorian calendar], 1838, it erupted with a cracking sound and a loud rumble and began emitting flame and ash.  The westerly wind blowing at the time carried the smoke along the Alaska Peninsula as far as Katmai.  This smoke hid the mountain for the entire eruption.  However, when the volcano finally became visible again, it only emitted smoke, from the same places as in 1852; there was no longer any fire.  The eruption ceased in April 1839.  The first vague reports of this volcano were given in I. Veniaminov, the present metropolitan of Moscow, in his Notes on the Islands of the Unalaska District.  For this reason, Grewingk calls this volcano 'Veniaminov.'\"","StartYear":1830,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1839,"EndMonth":4,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Veniaminof","ParentVolcano":"Veniaminof","VolcanoID":"ak301","ParentVolcanoID":"ak301"},{"ID":450,"Name":"Isanotski 1830","Description":"   Several historical eruptions have been attributed to Isanotski, most notably the explosive March 10, 1825 eruption.  However, according to Alaska Volcano Observatory geologists, Isanotski shows no evidence of having any possibly Holocene vents.  Alaska Volcano Observatory geologists flying over Isanotski in 1997, 1998, and 1999 failed to find any apparently Holocene vents on Isanotski, and saw only glacially polished rocks.  Geologists from AVO suggest that all historical eruptions of Isanotski instead be attributed to Shishaldin.  Field investigations of Shishaldin reveal numerous Holocene vents, including a very large flank feature called \"The Blister\" that has melted through the modern ice cover of Shishaldin, and which could be the vent for eruptions during the 1800s.  In addition, several streams draining from Shishaldin look capable of carrying large amounts of sediment to the sea (as described by Veniaminov for the March 10, 1825 eruption), but all of the streams draining Isanotski are heavily vegetated, suggesting that they did not carry large amount of sediment within the last few hundred years (Chris Nye, personal commun., 2004).\r\n   Veniaminov (1840) is pretty clear that this eruption came from Shishaldin.  Grewingk (1850) also states that Shishaldin was erupting in 1830.  Coats (1950) however, states that Isanotski and Shishaldin were erupting in 1830.","StartYear":1830,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Isanotski","ParentVolcano":"Isanotski","VolcanoID":"ak135","ParentVolcanoID":"ak135"},{"ID":408,"Name":"Fisher 1830/8","Description":"   Veniaminov (1840, translated by Lydia T. Black and R.H. Geoghegan, 1984), writing of a peak that may be Fisher caldera, reports that in \"August, 1830, the summit of this peak exploded again, but without any other special phenomena.\"","StartYear":1830,"StartMonth":8,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Fisher","ParentVolcano":"Fisher","VolcanoID":"ak100","ParentVolcanoID":"ak100"},{"ID":131,"Name":"Makushin 1836","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) writes that in 1836, Makushin was smoking.  Dall (1870), Davidson (1884), and Plummer (1898) report that Makushin was smoking in 1838.","StartYear":1836,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1838,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":348,"Name":"Shishaldin 1836","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) reports \"three smoking locations on Unimak\" and Shishaldin \"erupting with fire\" in 1836.  This eruption is not found in subsequent compilations (other than Sapper, 1917), although other compilations list a 1838 eruption for Shishaldin that is not listed in Grewingk.","StartYear":1836,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":284,"Name":"Cleveland 1836","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) reports Tanak-Angunakh smoking in 1836.  All subsequent compilers seem to refer to this event as occurring in 1838.  There is some confusion as to whether \"Tanak-Angunach\" refers to Carlisle volcano or Mount Cleveland.  From Miller and others (1998): \"Various names were applied to Carlisle on early hydrographic charts, including Uliaga, Kigalgin and variants thereof; it was also sometimes referred to along with the western half of Chuginadak Island, as Tanak-Angunak.  It is thus possible that some of the activity ascribed to Carlisle should be attributed to Uliaga or Mount Cleveland (Coats, 1950).\"\r\n      In support of this \"Tanak-Angunak\" referring to Chuginadak Island (the island Cleveland Volcano is part of) is Grewingk's description of Tanak-Angunak:  \"* * * oblong with a steep south side.  An active volcano rises on its western side.  According to an Aleutian legend it once formed an island by itself.  But the dividing strait was filled in when a mountain collapsed.  At the foot of this mountain there is a spring so hot that it can be used to cook in.\"","StartYear":1836,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":189,"Name":"Pavlof 1838","Description":"   Dall (1870) reports that Pavlof smoked in 1838.  Hantke (1955) attributes this eruption to the southern vent.  Jacob and Hauksson (1983) report that possibly normal explosions occurred during this eruption, or perhaps only solfataric activity.","StartYear":1838,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":229,"Name":"Akutan 1838","Description":"   Dall (1870) reports Akutan smoking in 1838.","StartYear":1838,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":329,"Name":"Carlisle 1838","Description":"   Documentation of early eruptions in the Islands of the Four Mountains region is scanty and uncertain.  Previous compilers (Simkin and Siebert, 1994; Miller and others, 1998) have assigned this eruption to Carlisle.  Based on descriptive information found in Veniaminov (1840, translated by Lydia T. Black and R.H. Geoghegan, 1984) and  Grewingk (1850, translated 2003 by Fritz Jaensch), this eruption has been reassigned to Cleveland.  Please refer to Cleveland's eruptive history for information about this event.","StartYear":1838,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Carlisle","ParentVolcano":"Carlisle","VolcanoID":"ak40","ParentVolcanoID":"ak40"},{"ID":347,"Name":"Shishaldin 1838","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) does not report an eruption for Shishaldin during 1838, but rather 1836.  However, all other compilers report an eruption for Shishaldin during 1838.  Dall (1870; the first compiler after Grewingk) says Shishaldin \"emitted fire, and smoke arose from three points.\"  This description is very similar to Grewingk's description of the 1836 eruption.  It is unclear if these two citations are describing the same eruption (in 1836, rather than 1838?) or two separate eruptions.","StartYear":1838,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":349,"Name":"Shishaldin 1842","Description":"   From Kisslinger (1983), translating Doroshin (1870): \"In 1842, Shishaldin volcano on Unimak Island erupted, at which time lava flowed forth.  Flames appeared on the volcano intermittently thereafter.\"","StartYear":1842,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":132,"Name":"Makushin 1843","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) writes that Voznesenskii reported smoke from Makushin in 1843 and 1844.  Beginning with Coats (1950), other compilers list the date for this eruption as being 1845.  All previous compilers (except Doroshin (1870) - he lists 1845 as the eruption date) list 1843 or 1844 as eruption dates.  Perhaps there was a second episode of smoking at Makushin in 1845, or perhaps there is a typographical error in Doroshin or Coats.  Jacob and Hauksson (1983) and Arce (1983) include both 1844 and 1845 as eruptions.","StartYear":1843,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1844,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":1,"EndQualifierUnit":"Years","Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":419,"Name":"Iliamna 1843","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) writes that Voznesenskii reported Iliamna active in 1843.","StartYear":1843,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":67,"Name":"Korovin 1844","Description":"   Grewingk (1850, translated 2003 by Fritz Jaensch) writes that Voznesenskii reported weak smoke from Korovin's crater in 1844.","StartYear":1844,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Korovin","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak171","ParentVolcanoID":"ak17"},{"ID":190,"Name":"Pavlof 1844/8","Description":"   From Kisslinger (1983), translating Doroshin (1870): \"The inhabitants of the village of Belkofski, 35 versts south of the volcano, say that they did not see any eruption in 1846, but that they did see one on August 12 [August 24, Gregorian calendar], 1844.  This date is partially confirmed by the dispatch of the Unalaska office for August 20 [September 1, Gregorian caldenar], 1845 (No. 74) which states that 'Pavlof Volcano has recently been producing large eruptions, at times emitting flames, soot, stones, etc.  These eruptions are accompanied by a noise like a thunder clap, and by a shaking of the environs.'  Which report is more accurate?  Both are identically accurate, i.e., there were two eruptions.\"  It is probable that Doroshin is stating here that there was an eruption in 1846 and also one in 1845 or 1844.\r\n   Subsequent reporters have cited only the 1844 or the 1845 date for this eruption.  However, Simkin and Siebert (1994) write that the eruption occurred in August 1845, not 1844.","StartYear":1844,"StartMonth":8,"StartDay":12,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":230,"Name":"Akutan 1845","Description":"   Kisslinger (1983), translating Doroshin (1870): \"In the same year [1845] volcanoes on Akutan smoked, as did Makushin Volcano on Unalaska Island.\"","StartYear":1845,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":452,"Name":"Isanotski 1845","Description":"   Several historical eruptions have been attributed to Isanotski, most notably the explosive March 10, 1825 eruption.  However, according to Alaska Volcano Observatory geologists, Isanotski shows no evidence of having any possibly Holocene vents.  Alaska Volcano Observatory geologists flying over Isanotski in 1997, 1998, and 1999 failed to find any apparently Holocene vents on Isanotski, and saw only glacially polished rocks.  Geologists from AVO suggest that all historical eruptions of Isanotski instead be attributed to Shishaldin.  Field investigations of Shishaldin reveal numerous Holocene vents, including a very large flank feature called \"The Blister\" that has melted through the modern ice cover of Shishaldin, and which could be the vent for eruptions during the 1800s.  In addition, several streams draining from Shishaldin look capable of carrying large amounts of sediment to the sea (as described by Veniaminov for the March 10, 1825 eruption), but all of the streams draining Isanotski are heavily vegetated, suggesting that they did not carry large amount of sediment within the last few hundred years (Chris Nye, personal commun., 2004).\r\n   Coats (1950) lists Isanotski as \"active\" in 1845.","StartYear":1845,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Isanotski","ParentVolcano":"Isanotski","VolcanoID":"ak135","ParentVolcanoID":"ak135"},{"ID":191,"Name":"Pavlof 1846/8","Description":"   From Kisslinger (1983), translating Doroshin (1870): \"The mountain burst with a loud 'cannonade' at this site [eastern slope of the mountain, where a pre-existing lava flow was] in August, 1846.  Smoke poured out in clouds from a fissure, ash fell, and flames appeared.  Flames also shot up from the summit.  A northwest wind dispersed both the smoke and the ash that obscured from the inhabitants of Pavlof the islands at the mouth of the bay.  The ash was carried to the village of Pavlof, where it was necessary to place a covering over the fish that were hung up.  Smoke and ash were carried to Unga Island (about 85 kilometers to the east), where people also protected drying fish from ash by covering it with matting.  The eruption continued for only one day.  At night, flames were visible along the western slope as well.  There were no flames anywhere the following day, but vapor rose from the mountain; soon this also ceased.  At present only smoke rises from the northern side of the summit.\r\n   \"That is how the inhabitants of the village of Pavlof describe the last eruption.  They remember the date because it coincided with the construction of a chapel. * * *   The inhabitants of Unga Island describe the 1846 eruption as follows: 'The sun was low and the western horizon clear, when we espied in that direction a black cloud, which rose like smoke from a pipe.  The day grew darker and darker.  Finally it became so dark that you couldn't see your hand in front of your face, and something as fine as powder fell down on us.  However, a wind quickly carried the cloud past; the morning was bright.'\"","StartYear":1846,"StartMonth":8,"StartDay":15,"StartTime":null,"StartQualifier":14,"StartQualifierUnit":"Days","EndYear":1846,"EndMonth":8,"EndDay":15,"EndTime":null,"EndQualifier":14,"EndQualifierUnit":"","Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":231,"Name":"Akutan 1848/3","Description":"   Kisslinger (1983), translating Doroshin (1870): \"In 1848, in the first few days of March, a volcano on Akutan began to eject flames, ash, and stones, with a rumble and a shaking of the ground.\"","StartYear":1848,"StartMonth":3,"StartDay":5,"StartTime":null,"StartQualifier":4,"StartQualifierUnit":"Days","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":1441,"Name":"Akutan Cascade Bight Valley Young Lahar","Description":"From Waythomas (1999): \"A second, younger noncohesive lahar deposit is present at sections 74, 56, 57, 41, and 41a (Fig. 10 [in original text]). This deposit is similar to the basal gray lahar except that it is deformed and reworked. Folded strata, hummocky surface morphology (Fig. 11 [in original text]), and a prominent headscarp in the upper part of the valley indicate that, after deposition, approximately 3 km 2 of the lahar (70-80% of the total area) was remobilized and flowed a short distance downstream. This may have been caused by ground motion associated with local earthquakes, which are common in this region. The lack of a tephra mantle or soil on the upper lahar in Cascade Bight valley also indicates that the lahar is young, possibly 100 years old or less.\"","StartYear":1850,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":179,"Name":"Chiginagak 1852","Description":"   Coats (1950) reports that Chiginagak was smoking in 1852.   Powers (1958) writes that Chiginagak was steaming, with intermittent smoke in 1852.  Perhaps the original source for this event is Doroshin, who viewed Chiginagak in 1852 and described it as follows (J.B. Kisslinger translation, 1983): \"This volcano, which I also saw rising from behind some mountains, has a broad crater, the southern side of which has been destroyed.  Snow shows white within the crater.  Smoke rises from the western slope of the mountain.\"  This description is probably of the prominent fumaroles on Chiginagak and not a volcanic eruption.","StartYear":1852,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Chiginagak","ParentVolcano":"Chiginagak","VolcanoID":"ak49","ParentVolcanoID":"ak49"},{"ID":192,"Name":"Pavlof 1852","Description":"   Coats (1950) reports smoke from Pavlof in 1852.  Hantke (1955) reports this eruption as from the 'southern vent', but Jacob and Hauksson (1983) report that this was not an eruption, but rather solfataric activity and steaming from a vent high on the north flank.","StartYear":1852,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":306,"Name":"Veniaminof 1852","Description":"   Kisslinger (1983), translating Doroshin (1870): Doroshin viewed Veniaminof smoking in 1852, and also a notation that 'there was no longer any fire.\"","StartYear":1852,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Veniaminof","ParentVolcano":"Veniaminof","VolcanoID":"ak301","ParentVolcanoID":"ak301"},{"ID":404,"Name":"Peulik 1852","Description":"   From Kisslinger (1983), translating Doroshin (1870): \"In the summer of 1852, I proceeded from here on a southwesterly course along the eastern coast of the Alaskan Peninsula.  At approximately 57 degrees 31 minutes latitude, 155 degrees 55 minutes longitude, I saw rising from behind a mountain the crater of Mt. Peulik. * * * I saw only smoke, coming from the south side of the crater.  There are petroleum sources nearby.  When portaging from Lake Iz'iagyk to the lake from which the Ugashik River flows [i.e., Upper Ugashik Lake], one must pass near this volcano.  I would like to suggest that Mt. Peulik is identical with the mountain that is called 'Bocharov' on maps.\"  Miller (2004) qualifies this report, stating: \"Because Mount Peulik is separated from other prominent active volcanic edifices in the region [see fig. 1 in original text], these reports [of activity in 1814 and 1852] are credible and may represent the most recent eruptions at the center.\"","StartYear":1852,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Peulik","ParentVolcano":"Ugashik-Peulik","VolcanoID":"ak212","ParentVolcanoID":"ak295"},{"ID":232,"Name":"Akutan 1852/9","Description":"   Davidson (1884), speaking of two peaks on Akutan: \"I made a sketch of them in 1867, when the eastern one was smoking, and I was then informed by one of the Russian-American navigators that on the night of Sept. 1, 1852, he saw one or two eruptions form the northwest side of these two cones.  Frequently fire and great noises issue from the eastern peak.\"","StartYear":1852,"StartMonth":9,"StartDay":1,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":550,"Name":"Shishaldin 1856/7","Description":"   From Lander (1996): \"1856, July 26.  There was a volcanic eruption in Unimak Pass.  It is described by Captain Neville, of the whaler Alice Fraser.  Crossing Unimak Pass on his ship with six other whalers, he observed an enormous mass of dense black smoke from a volcanic eruption on the adjacent islands.  The ships were becalmed, leaving them exposed to the danger of the eruption.  After twelve hours, a light breeze enabled the ships to begin moving away in the pitch blackness.  Sailing west and north of the eastern shore they were near the northern base of the volcano when a prolonged dull rumble was heard and an underwater eruption began almost under the flotilla.  The water churned and began to rise stormily in the form of disorganized waves.  Then it rushed up, as if ejected from an enormous spring, forming a dazzling column of water of colossal height.  A shaft of fire and smoke rose from the depths, with peals of thunder.  Volcanic ejecta, the size of walnuts to cannon balls, landed on the ships.  This phase ended quickly and water rushed into the abyss forming a colossal whirlpool.  The ships escaped (Perrey, 1859, 1866 : in French).  The volcano was Mount Shishaldin.\"\r\n  From Soloviev and Go, 1974: \"There was a volcanic eruption in Unimak Pass, apparently near 54 degrees 34 minutes N., 165 degrees W.  It is described by Neville, the captain of the whaler 'Alice Fraser.'  Crossing the pass on his ship with six other whalers, he observed that as a result of the volcanic eruption, enormous masses of dense black smoke were rising over the conical peaks of the mountains on the adjacent islands.\r\n   \"He and the captains of the other whalers made ready to round the eastern tip of Unalaska Island, in order to get a good look at the eruption, which was accompanied by a prolonged dull roar and tremors, which by that time they had already felt repeatedly.  At precisely this instant, the strong breeze which had been blowing completely died down, and the ships found themselves at the mercy of the eruption, in danger of being run aground.\r\n   \"The eruption, lasting several hours with variable intensity, then appeared to reach its climax.  The thunder of the eruption and the underground rumble rapidly intensified and became ever more ominous.  The air was so still that dense black smoke was ejected straight up into the sky, without deviating in the slightest.  It spread out above, at cloud level, and ashes, like flakes of snow, fell down in abundance.\r\n   \"After 12 hours of still, a light breeze arose from the south, enabling the ships to move away from the volcano.  But this breeze carried the column of smoke to the water surface, and a pitch darkness set in over a distance, as was later established, of more than 180 km, and the ships lost sight of the shore.\r\n   \"The ashes fell like snow in a blizzard, covering the ships with gray substance from the deck to the top of the masts, blinding and choking all those on deck.\r\n   \"Sailing west and north of the eastern shore, the ships tore out of the cloud of smoke.  When they were near the northern base of the volcano, a prolonged dull rumble pealed out under them, and an underwater eruption occurred almost right in the centre of the flotilla.\r\n   \"First the water churned and began to rise stormily in the form of disorderly waves.  Then it rushed up, as if ejected from an enormous spring, forming a dazzling column of water of colossal height, which gradually disintegrated.  Then a shaft of fire and smoke rose from the bottom upwards with peals of thunder.  Lava and stones from a walnut to a cannon ball were disgorged, and fell on deck.  \r\n   \"This lasted no more than an instant, and the eruption ended as quickly as it had began.  The water rushed into the abyss which had formed, forming a colossal whirlpool.  The noise was like Niagara Falls.\r\n   \"The ships rushed to safety, leaving the volcano in a state of regular alternation of relative calm and eruption (Perrey, 1859, 1866; [in French]; Mushketov and Orlov 1893 [in Russian]).  This event is mentioned very briefly in a number of publications (Sieberg, 1932 [in German]; Iida and others, 1967; Cox and Pararas-Carayannis, 1969).\"","StartYear":1856,"StartMonth":7,"StartDay":26,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":233,"Name":"Akutan 1862","Description":"   Byers and Barth (1953) report Akutan smoking in 1862.  Dall (1870) does not mention this event in his compilation.","StartYear":1862,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":133,"Name":"Makushin 1865","Description":"   Dall (1870) reports Makushin was active in 1865.  Beget and others (2000) interpret this as Makushin was smoking.","StartYear":1865,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":234,"Name":"Akutan 1865","Description":"   Dall (1870) reports that in 1865, \"light was observed at night in the direction of Akhun and Akutan.\"","StartYear":1865,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":350,"Name":"Shishaldin 1865","Description":"   Dall (1870) reported Shishaldin smoking in 1865.","StartYear":1865,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":193,"Name":"Pavlof 1866/3","Description":"   The exact location of this eruption is uncertain, but nearly all compilers (Sapper, 1917; Coats, 1950; Hantke, 1955; Powers, 1958; Jacob and Hauksson, 1983; Simkin and Siebert, 1994; Miller and others, 1998) attribute it to Pavlof.  Doroshin (1870) appears to be the original source for this eruption.  \r\n   Kisslinger (1983), translating Doroshin (1870), reports that \"At about 3 a.m. on March 14 [March 26, Gregorian calendar], 1866, at Pavlof Harbor on Kodiak Island there was impenetrable darkness for 15 minutes, and ash fell.  It was completely silent while this happened.  According to reports from Afognak Island, and from the village of Katmai on the Alaska Peninsula where the same thing was experienced, the cloud of ash moved from the south, probably as the result of an eruption of one of the voclanoes of the Alaska Peninsula.  Ash fell at Pavlof Harbor to a depth of one-quarter inch.  There was neither a noise nor an earthquake at the time of this occurrence.\r\n   \"From reprots obtained recently, the place of eruption has been determined more definitely; it occurred to the northwest of Katmai village, on the Alaska Peninsula, at a newly formed volcano.  In fact, the smoking volcano Kutliukhat [Mount Katmai] is located in the aforesaid direction.\"\r\n   Although Doroshin seems to suggest that the place of eruption was *not* Pavlof, but instead somewhere farther north, the ashfall distribution pattern, prevailing winds, and tephra deposits in the Katmai area do not support this theory.  The most likely volcano to have deposited 1/4 of an inch worth of ash at Pavlof Harbor is a volcano near Pavlof Harbor (Judy Fierstien, 2006, personal communication.)  Although Doroshin indicates that Pavlof Harbor is on Kodiak Island, modern references to Pavlof Harbor concern a harbor near Pavlof Volcano.\r\n   Sapper (1917) reports a strong ash eruption in March, 1866, citing Fuchs, and Mercalli, after Perrey.  No mention of this eruption is found in Becker (1898).","StartYear":1866,"StartMonth":3,"StartDay":14,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":235,"Name":"Akutan 1867","Description":"   Davidson (1884): speaking of two peaks on Akutan: \"I made a sketch of them in 1867, when the eastern one was smoking * * *.\"\r\nByers and Barth (1953) report that Akutan in 1867 produced \"smoke, fire, and 'great noises.'\"","StartYear":1867,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":421,"Name":"Iliamna 1867/3","Description":"   From Juhle (1955): \"According to Dall (1894) the March 1867 eruption [of Iliamna] produced a light pumice and ash fall on St. Paul, Kodiak Island 165 miles to the southeast.\"\r\n   This statement is confusing, because Juhle is referencing Dall, 1894, in Science, volume 3.  However, volume 3 of Science was published in 1884, and, although there is an article by Dall published in that issue, it does not discuss Iliamna.\r\n   Juhle continues with: \"I.C. Russell (1897, p. 211 [listed in bibliography as 1910]) writes: 'In the summer of 1895 it was sending out five or six columns of steam and seemed peaceful enough.  A few years ago, however, it was in violent eruption and discharged such a profusion of hot dust and lapilli that the timber over hundreds of square miles of tableland was killed.'  Unfortunately the source of this information is not given.  Perhaps this refers to the March 1867 eruption.  The magnitude of the eruption seems somewhat exaggerated.  Today only a few cinder lapilli, which may be remnants of this ash fall, can be found in protected topographic depressions at high altitudes.\"\r\n   Miller and others (1998) doubt the veracity of this eruption:  \"although Coats (1950) lists several reports of 'smoke', and an eruption in 1867, documentation is poor and validity of the reports is questionable.  Except for the summit fumarolic activity, it is uncertain and perhaps unlikely that Iliamna Volcano has been historically active.\"","StartYear":1867,"StartMonth":3,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":134,"Name":"Makushin 1867/9","Description":"   Davidson (1884) climbed Makushin in 1867.  On September 8, 1867, his party was ascending Makushin: \"At 9:30 a.m. they reached the base of a very steep mountain, which we afterwards saw from the vessel, its almost perpendicular, black, scarred front looking like a great fortress on the outer flank of the snow-covered mountains.  At its base the herbage was removed, and the earth at six inches below the surface was so hot that no one could bear his hands in it.  The surface was cool; but, curiously enough, no one thought of observing the temperatures.\"  At 9 a.m. on September 9, the expedition reached the crater: \"For a few minutes the clouds broke away, and almost beneath the party lay the crater, rolling out volumes of smoke and yellow sulfurous vapors.\"","StartYear":1867,"StartMonth":9,"StartDay":9,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":135,"Name":"Makushin 1871","Description":"   Becker (1898) writes that Makushin steamed from 1871-1874.  This activity probably does not constitute a volcanic eruption.","StartYear":1871,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1874,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":351,"Name":"Shishaldin 1871","Description":"   Becker (1898) reported steaming at Shishaldin from 1871-1874.  However, Sapper (1917) points out that this notation of Becker's is identical to his remarks for Makushin, raising the possibility that this report is erroneous.","StartYear":1871,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1874,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":15,"Name":"Mount Young 1873","Description":"   From Miller and others (1998): \"Records of volcanism on Semisopochnoi Island are scant; historical eruptions could have involved the small Lakeshore Cone and Sugarloaf cone in addition to Mount Cerberus [Mount Young].  However, since at least one of the early reports specified that the activity noted was in the center of the island, and Mount Cerberus is the least eroded of the recent cones, it is believed to have been the source of most recorded events (Coats, 1950; 1959).\"\r\n   From Becker (1898): \"1873.  Semisopochnoi active.\"","StartYear":1873,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mount Young","ParentVolcano":"Semisopochnoi","VolcanoID":"ak44","ParentVolcanoID":"ak248"},{"ID":22,"Name":"Gareloi 1873","Description":"   Becker (1898) reports Gareloi active in 1873.","StartYear":1873,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Gareloi","ParentVolcano":"Gareloi","VolcanoID":"ak106","ParentVolcanoID":"ak106"},{"ID":101,"Name":"Yunaska 1873","Description":"   Becker (1898) reports steam from Yunaska in 1873.","StartYear":1873,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Yunaska","ParentVolcano":"Yunaska","VolcanoID":"ak329","ParentVolcanoID":"ak329"},{"ID":307,"Name":"Veniaminof 1874/7","Description":"   From Dall (1918): \"While surveying in Port Moller in 1874 for the Coast Survey, the western edge of Mt. Veniaminoff [sic] was visible from the sea with intermittent clouds of steam and blackish smoke puffing from the invisible crater at intervals.\"","StartYear":1874,"StartMonth":7,"StartDay":null,"StartTime":null,"StartQualifier":2,"StartQualifierUnit":"Months","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Veniaminof","ParentVolcano":"Veniaminof","VolcanoID":"ak301","ParentVolcanoID":"ak301"},{"ID":92,"Name":"Amukta 1876","Description":"   Coats (1950) reports smoke from Amukta in 1876.  An article in the journal Nature (1879) reports Amukta in eruption in 1878, however.  The Nature article states: \"In the volcanic series of the Aleutian Islands, the volcanoes on Amukta, Tscheguluk, and the Vsevidok volcano (almost 2,800 m high) on Umnak were in eruption.\"","StartYear":1876,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Amukta","ParentVolcano":"Amukta","VolcanoID":"ak10","ParentVolcanoID":"ak10"},{"ID":422,"Name":"Iliamna 1876","Description":"   Becker (1898) lists an eruption from Iliamna in 1876.  Sapper (1917) and Coats (1950) call this eruption \"smoke.\"  However, Kienle and Swanson (1983) report this eruption as a \"major eruption spreading ash to Kenai Peninsula (Rymer and Sims, 1976).  The description for this 1876 eruption sounds similar to the description of the 1867 eruption.  Waythomas and Miller (1999) suggest that perhaps this event was a flank collapse, with debris avalanches and lahars.\r\n   Miller and others (1998) doubt the veracity of this eruption:  \"although Coats (1950) lists several reports of 'smoke', and an eruption in 1867, documentation is poor and validity of the reports is questionable.  Except for the summit fumarolic activity, it is uncertain and perhaps unlikely that Iliamna Volcano has been historically active.\"\r\n   Perhaps 1867 and 1876 refer to two separate events, or perhaps someone has reversed a \"76\" or a \"67\" somewhere along the way.  It is interesting to note that although Becker lists the 1876 event, he does not list the 1867 event.","StartYear":1876,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":109,"Name":"Vsevidof 1878","Description":"   From Miller and others (1998): \"Recorded activity in 1878 may have been form a radial fissure eruption on the west flank; this event may have produced the youngest dacite flow, which extends west-southwest to Cape Kigushimkada (Byers, 1959).\"  Sapper (1917) wrote that Vsevidof had a brief flame and ash eruption and a new crater developed from which came steam and hot cooking mud.  This new crater appeared between Vsevidof and the settlement.  Sapper also notes that there were many hot springs.  Hantke (1962) notes that about 1878 large lava streamed out of ruptures in the west flank.  The eruption lasted less than two years: Dall (1918) writes that he saw Vsevidof in 1880, the \"image of perfect peace\", and does not mention the 1878 event.","StartYear":1878,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Vsevidof","ParentVolcano":"Vsevidof","VolcanoID":"ak307","ParentVolcanoID":"ak307"},{"ID":164,"Name":"Okmok 1878","Description":"   From Grey (2003): \"A new crater is reported to have formed within the caldera in 1878 (Hantke, 1951), accompanied by earthquakes and a tsunami (location unknown).  This could refer to the birth of Cone A, but since Hantke offers no additional information or references to support this notion, the report is apocryphal at best.  It is intriguing to note that eruptions are also reported at Vsevidof, on the southwestern end of Umnak Island, in 1817, 1830, and 1878 (Miller and others, 1998).  Of particular interest is the suggestion by Miller and others that the 1878 activity of Vsevidof 'may have been from a radial fissure eruption on the west flank; this event may have produced the youngest dacite flow, which extends west-southwest to Cape Kigushimkada.'  Such a fissure eruption would probably produce earthquakes and could account for Hantke's 'new crater,' though not located inside a caldera.  It is thus possible that Hantke misinterpreted the location of the 1878 activity, and there may not have been an eruption at Okmok in that year at all.\"\r\n   Sapper (1917), compiling information from Petroff (1884) and Fuchs, reports \"a brief flame and ash eruption and a new crater developed from which came steam and hot cooking mud.  This new crater appeared between Vsevidof and the settlement.\"  This statement seems to support Miller and others's (1998) assertion that there was a radial fissure eruption at Vsevidof in 1878.","StartYear":1878,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Okmok","ParentVolcano":"Okmok","VolcanoID":"ak206","ParentVolcanoID":"ak206"},{"ID":110,"Name":"Vsevidof 1880","Description":"   Coats (1950) reports smoke at Vsevidof in 1880.","StartYear":1880,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Vsevidof","ParentVolcano":"Vsevidof","VolcanoID":"ak307","ParentVolcanoID":"ak307"},{"ID":136,"Name":"Makushin 1880","Description":"   Petroff (1884) reports that Veniaminov reported earthquakes at Makushin in 1880.  This is certainly an error, as Veniaminof died in 1879.  Becker (1898) reports Makushin was steaming during 1880.  It is uncertain if the steam and earthquake are associated with a volcanic eruption from Makushin in 1880.","StartYear":1880,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":194,"Name":"Pavlof 1880","Description":"   Becker (1898) reports a \"red glare\" was seen from Pavlof in 1880.","StartYear":1880,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":352,"Name":"Shishaldin 1880","Description":"   Becker reported smoke from Shishaldin between 1880-1881.  However, Sapper (1917) points out that this notation of Becker's is identical to his remarks for Makushin, raising the possibility that this report is erroneous.  Many subsequent compilers list smoke from Shishaldin during 1880-1881.","StartYear":1880,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1881,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":436,"Name":"Redoubt 1881","Description":"   From Cordeiro (1910): \"To the eastward, Redoubt Volcano, 11,060 feet high, is constantly smoking, with periods of exaggerated activity.  Fire has been seen issuing from its summit far out at sea.  A great eruption took place in 1881, when a party of native hunters half-way up its slopes were overwhelmed by a lava-flow and only two escaped.\"  This account is not mentioned in other eruption compilations.","StartYear":1881,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Redoubt","ParentVolcano":"Redoubt","VolcanoID":"ak231","ParentVolcanoID":"ak231"},{"ID":137,"Name":"Makushin 1883","Description":"   Becker (1883) reports an ash eruption from Makushin in 1883.","StartYear":1883,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":236,"Name":"Akutan 1883","Description":"   Becker (1898) reported a steam and ash eruption at Akutan in 1883.","StartYear":1883,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":353,"Name":"Shishaldin 1883","Description":"   Becker reported steam and ash from Shishaldin in 1883.  However, Sapper (1917) points out that this notation of Becker's is identical to his remarks for Makushin, raising the possibility that this report is erroneous.","StartYear":1883,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":114,"Name":"Bogoslof 1883/8","Description":"   The first indicator of this eruption was from residents of Unalaska, who first noticed steam rising from the ocean somewhat north of Ship Rock in 1882 (Merriam, 1901).  In the fall of 1883, the eruption of Bogoslof was evident.  The new island created by this eruption was called New Bogoslof or Grewingk, and is now called Fire Island (Miller and others, 1998).  Miller and others summarizes as follows: \"In 1884 the cone (presumably the dome was destroyed) had a diameter of 1 km, a craggy profile, and pinnacles that reached an altitude of about 150 m (Byers, 1959).  In May of that year, officers of the revenue Marine steamer Corwin examined the Bogoslof group.  They found Ship Rock, Old Bogoslof, and New Bogoslof connected into a single land mass by bars of volcanic debris and sand-bouldered beaches.  Second Lieutenant J.C. Cantwell observed 15 separate vents on the upper third of New Bogoslof cone issuing jets of steam with great force and regularity; thick sulfur deposits surrounded most of the vents, and the temperature in a crack near the summit was estimated to exceed 260 degrees C.  Great quantities of fine ash coated the slopes, but little coarse ejecta of flow lava was encountered (Henning and others, 1976).  In 1895, New Bogoslof was still steaming vigorously, and was a flat-topped structure about 90 m high, separated by several hundred meters of open water from Old Bogoslof.  By 1897 New Bogoslof had cooled (Byers, 1959).\r\n   Further details about the eruption are available from many sources; some of the most prominent accounts are summarized below.\r\n   Merriam (1901) wrote: \"At the time of its discovery, September 27, 1883, by Captain Anderson of the schooner \"Matthew Turner\", it was in active eruption, throwing out large masses of heated rock and great volumes of smoke, steam, and ashes, which came from the apex and from numerous fissures on the sides and base, some of which were under the water-line.  Large boulders were shot high in the air, which descending and striking the water, sent forth steam and a hissing sound.  After nightfall fire was observed on the island. A  month later Captain Hague of the schooner \"Dora\" approached it within a mile.  He is quoted as saying that black smoke, like that from burning tar, was issuing from it, that it threw out flame, smoke, and red-hot rocks; and that, among the sea-lions observed near by were a number which had been scalded so that the hair had come off.  He thinks many were killed.  From the descriptions given him by  Captain Anderson and Captain Hague, Professor George Davidson, of San Francisco, made a drawing, reproduced on page 206 of this article, representing the new volcano in the fall of 1883.  Its height was estimated at from 800 to 1,200 feet.  On October 20th of the same year the inhabitants of Unalaska were startled by an ominous black cloud, which appeared in the north and grew rapidly until it overspread the entire heavens and cut off the light of the sun.  It then settled down very low and the air became dark like night.  It finally broke and disappeared in a shower of ashes, which covered the ground and the houses, and adhered to the windows so that it was impossible to see through them.  The first landing on New Bogoslof was made by the officers of the Revenue steamer Corwin (Captain M.A. Healy) on May 21, 1884, nine months after its discovery.  Its altitude was found to be about 500 feet.  No crater was discovered, but there was a 'great fissure,' the interior of which could not be seen owning to the steam, fumes of sulphur, and heat, which rendered entrance into it extremely dangerous if not impossible.\"\r\n   Merrill (1889) reports that the composition of the ashes which fell on Unalaska and the composition of volcanic samples collected from this eruption are so similar as to definitively state that the October 20, 1883 Unalaska ash came from Bogoslof.\r\n   Byers summarizes the remaining years of this eruption as follows: \"In 1891, Merriam (1901, p. 313) visited the Bogoslof Islands and found steam and sulfur fumes escaping with a roaring noise from the principal fissure of New Bogoslof.  An open channel separated Old and New Bogoslof.  In 1895 when Becker and Dall (Becker, 1989, p. 26; Merriam, 1901, p. 317) visited the Bogoslof Islands, New Bogoslof was still steaming 'vigorously, though not violently' and had also been changed to a flat-topped island about 300 feet in altitude.  Later reports in 1897 and 1899 by passing mariners indicate that New Bogoslof or Grewingk Island had finally cooled (Merriam, 1901, p. 319-320).\"\r\n   Newhall and Melson (1983) estimate the volume of the lava dome produced in these eruptions to be about 40x10^6 cubic meters.","StartYear":1883,"StartMonth":8,"StartDay":17,"StartTime":null,"StartQualifier":5,"StartQualifierUnit":"Months","EndYear":1895,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":2,"EndQualifierUnit":"Years","Volcano":"Bogoslof","ParentVolcano":"Bogoslof","VolcanoID":"ak29","ParentVolcanoID":"ak29"},{"ID":332,"Name":"Augustine 1883/10","Description":"     Waitt and Beget (2009) summarize the 1883 eruption as follows: \"1883 is the first Augustine eruption documented to some extent by contemporaneous written accounts: an unpublished logbook of the Alaska Commercial Company post situated atop the spit at English Bay, published summaries by Dall (1884), Davidson (1884), and Becker (1898), an unpublished letter and an unpublished mission report both of 1884, and field notes by J.E. Spurr in 1898.\r\n   \"On the 6th of October 1883, Augustine Volcano -- or Chernoburoy (variously spelt) as the Russians knew it -- generated a tsunami and an ash plume experienced from English Bay 85 km away on the east mainland. The record book of the Alaska Commercial Company (1883) at Alexandrovsk (English Bay) records various routine data for 6 October 1883. Then this entry:\r\n   'At this Morning at 8.15 o'clock 4 Tidal Waves flowed with a westerly current, one following the other at a rate of 30 miles p. hour into the shore, the sea rising 20 feet above the usual Level. At the same time the air became black and foggy, and it began to thunder. With this at the same time it began to rain a finely Powdered Brimstone Ashes, which lasted for about 10 Minutes, and which covered all the parts of Land and everything to a depth of over 1/4 of a inch, clearing up at 9 o'clock A.M. Cause of occurrence: Eruption of the active Volcano at the Island of Chonoborough. Rain of Ashes commencing again at 11. o'clock A.M. and lasting all day.'\r\n   \"And for 7 October:\r\n   'Volcano ejecting fire and heavy black Clouds of Smoke all day long.'\r\n   \"The geographer William Dall (1884) rushed into print summary information derived from George Davidson (USCGS) and from a Capt. Sands and a Capt. Cullie (Alaska Commercial Company) observed from English Bay and then the sea:\r\n   'Smoke first arose from the peak in August. On the morning of Oct. 6 the inhabitants heard a heavy report, and saw smoke and flames issuing from the summit of the island. The sky became obscured, and a few hours later there was a shower of pumice-dust. About half-past eight o'clock the same day an earthquake wave, estimated at thirty feet height, rolled in upon the shore, deluging the houses on the lowland, and washing the boats and canoes from the beach. It was followed by others of less height. The ash fell to a depth of several inches, and darkness required lamps to be lighted. At night flames were seen issuing from the summit. After the first disturbances were over, it was found that the northern slope of the summit had fallen to the level of the . . . shore, and the mountain appeared as if split in two. . . . The cleft . . . crosses the island from east to west.'\r\n   \"George Davidson, who for the USCGS mapped much of the Washington-Oregon-California coast in 1850-53 and the Alaska coast in 1867-69, was experienced with coastal ship captains and eyewitness reporting. Having been partly scooped of his own story by Dall, Davidson (1884) gives a more detailed account of Augustine's effects partly derived from 'settlers and fishing-parties' at English Bay:\r\n   'About eight o'clock on the morning of Oct. 6, 1883, the weather being beautifully clear, the wind light from the south-westward, and the tide at dead low water, the settlers and fishing-parties at English Harbor heard a heavy report to windward (Augustin bearing south-west by west three-fourths west by compass). So clear was the atmosphere that the opposite of north-western coast of the inlet was in clear view at a distance of more than 60 miles.\r\n   'When the heavy explosion was heard, vast and dense volumes of smoke were seen rolling out of the summit of St. Augustin, and moving to the north-eastward; and at the same time (according to a hunting-party in Kamishak Bay), a column of white vapor arose from the sea near the island, slowly ascending, and blending with the clouds. The sea was also greatly agitated and boiling, making it impossible for boats to land upon or to leave the island.\r\n   'From English Harbor . . . it was noticed that columns of smoke, as they gradually rose, spread over the visible heavens, and obscured the sky, doubtless under the influence of a higher current (probably north or northeast). Fine pumice-dust soon began to fall, but gently, some of it very fine, some very soft, without grit.\r\n   'At about twenty-five minutes past eight A.M., or twenty-five minutes after the great eruption, a great 'earthquake wave,' estimated as from twenty-five to thirty feet high, came upon Port Graham [English Bay] like a wall of water. It carried off all the fishing-boats from the point, and deluged the houses. This was followed, at intervals of about five minutes, by two other large waves, estimated at eighteen and fifteen feet; and during the day several large and irregular waves came into the harbor. The first wave took all the boats into the harbor, the receding wave swept them back again to the inlet, and they were finally stranded. Fortunately it was low water, or all of the people at the settlement must inevitably have been lost. The tides rise and fall about fourteen feet.\r\n   'These earthquake waves were felt at Kadiak [Kodiak], where they are doubtless on the register of the coast-survey tide-gauge at that place.'\r\n   \"An indirect but independent record of the sea waves striking the Kenai Peninsula mainland exists in a report of the Russian Orthodox priest heading the Kenai mission, Heiromonk Nikita, who after a visit of his southern parishes wrote on 28 May 1884:\r\n   'Influenza Kenai, Ninilchik, Seldovia, Alexandrovsky [English Bay], nearly all children up to 2 years of age were swept away. At the same time this region suffered from innundation caused by the eruption of Chernabura volcano, which is about 60 miles across the straight from Alexandrovsky. The innundation so frightened natives of Alexandrovsky that they moved their huts to higher ground in one night [Russian Orthodox church records, Diocese of Alaska, Library of Congress, microfilm copy of Reel 1, Box 400, University of Alaska Anchorage Archives].'\r\n   \"This report is consistent with Davidson's and Dall's that the largest sea wave was high enough to 'deluge the houses' at English Bay.\r\n   \"The volcano evidently continued in eruption at least intermittently for weeks or months. Some time after 10 November 1883 (when in schooner Kodiak Captains Cullie and Sands approached Augustine Island), Davidson (1884) includes in his account:\r\n   'The condition of the Island of Augustin or Chenaboura, according to the latest accounts, is this: --\r\n   'At night, from a distance of fifty or sixty miles, flames can be seen issuing from the summit of the volcano; and in the day-time vast volumes of smoke roll from it.'\r\n   \"Another entry in the Kenai Mission record by Heiromonk Nikita on 27 May 1885 reads:\r\n    'Earthquakes still quite frequent here [at Kenai?] and Chernabura is still smoking.'\r\n   \"Davidson's (1884) account includes several obvious errors of observation or interpretation, including a Capt. Cullie description rendered into a fanciful figure (Davidson, 1884, p. 188). A chagrined Davidson later tried to rectify this in a letter (unpublished) dated 5 November 1884 addressed to Prof. J.E. Hilgard, Superintendent of the USCGS. One of Davidson's late-1883 sources, Capt. Cullie of the Alaska Commercial Company at English Bay, had sailed past Augustine Island in June 1884. As reported in Davidson's November letter, Capt. Cullie saw from the north that:\r\n   '. . . from the summit a great slide of the mountain over half a mile broad had taken place towards the rocky boat harbor on the northnorthwestward.11 It appeared as if there had been a great sinking of the rocks under the summit leaving a face of wall overlooking the slide. Down this had poured the lava [sic] and erupted material to the base of the mountain and had pushed into the boat harbor and filled it up. In the upper part of lava [sic] outflow was issuing great volumes of white smoke . . .'\r\n   \"A later record about Augustine's preeruption 'boat harbor' exists in the field notes of USGS geologist J.A. Spurr (USGS archives):\r\n   'Oct. 17 (1898) Trader says here at Katmai that eighteen years ago [sic] three families from Kodiak went with families and baidarkas to St. Augustine Island to spend the winter. Built barabaras on the shore of a bay. The mountain began to shake continually and finally they took their families off, while they stayed on themselves. Finally the mountain began to shake so violently that they put all their effects in their bairdarkas and started on a stormy day. Scarcely were they at the mouth of the bay when an explosion occurred, ashes, boulders, and pumice began pouring down and the barabaras were buried and the bay filled up with debris. At the same time there were many tidal waves, so the natives nearly perished with fright, yet finally escaped.'\r\n   \"Becker's (1898) published account mostly reiterates information in Davidson (1884) and Dall (1884) about events of 6-7 October 1883 but includes a few details from a climb in 1895 by Becker and his assistant Purington nearly to the summit and to the new dome (Becker, 1898, p. 29):\r\n   '. . . Steam escaped from countless crevices, most of them on the inner cone [that is, a new dome] . . . . Masses were from time to time detached, rolling down to the bottom of the deep moat which separates the outer crater from the inner cone . . . . The inner cone [is] nearly as high as the outer rim.'\"\r\n   Waitt and Beget (2009) describe the Burr Point debris-avalanche deposit that formed during this eruption, evidence for a tsunami, the 1883 pyroclastic flow and surge deposits, and the 1883 lava dome in detail. \r\n   Simkin and others (1995) also calculate the volume of the lava flow plus the volume of the lava dome to be 0.13 cubic km.  Simkin and Siebert (2002- ) give an estimate of 0.13 +/- 0.04 cubic km for lava from this eruption, and 0.51 +/- 0.5 cubic km as a tephra volume.","StartYear":1883,"StartMonth":10,"StartDay":6,"StartTime":"08:00:00","StartQualifier":null,"StartQualifierUnit":"","EndYear":1884,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":398,"Name":"Wrangell 1884/10","Description":"   The journal of John Bremner, a prospector who lived among the Copper River Indians, was found at Nuchuk in 1886 by Heywood Walter Seton-Karr, and published by Seton-Karr in Shores and alps of Alaska (1887) records an eruptive event at Mt. Wrangell.  John Bremner's journal starts on September 1, 1884, but no metion is made of Wrangell until October 26: \"Clear but verey cold the floor of my cabin is frose two foot from the fire and I thought I had made it almost air tight so you see I am in no danger of melting with the heat.  I saw the Volcano smoking for the first time to-day it is the mountin laid down on the chart as Mt. Wrangle it dont look more than twenty-five or thirtey miles from here but the natives say it will take me three days to go thar I cant get one of them to go near it so I will have to go alone I sholl go as soon as the river is safe.\"\r\n   On February 3, 1885, Bremner describes a more robust eruption: \"A beautifull day not a cloud in the sky I was treated to a sight to-day that I wish you could have seen the volcano has been verey quite (quiet) a good while but to-day it is sending out a vast column of smoke and hurling imense stones hundreds of feet high in the air the mases it is throwing up must be verey large to be seen here it is at least thirty milles in a air line from here to the mouth of the crater it has mde no loud reports onley a sort of rumbling noise.\"\r\n   He continues on February 4, 1885: \"A little colder but pleasant the Volcano has stoped throwing stones ore making a noise but is still sending out an imense cloud of smoke it is verey beautifull not a breath of wind and the smoke ascends to a great hight in an imense colum before spreading out.\"  \r\n   His next entry is not until February 5, which states that the weather is cloudy.  The journal ends on February 7, with no further mentions of Wrangell.\r\n   Other reports of this eruption include: Becker (1898) recording that Wrangell \"in eruption\" in 1884, and Mendenhall (1903) reporting that Lieutenant Allen observed smoke from Wrangell in 1885.  Although some steam from Wrangell in 1884/1885 seems probable, an eruption as robust as the one Bremner describes is questionable.  It is doubtful that Bremner could have seen the sights he describes from a distance of ~30 miles. \r\n\r\nAVO thanks LeEric Marvin for directing us to Seton-Karr's book.","StartYear":1884,"StartMonth":10,"StartDay":26,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1885,"EndMonth":2,"EndDay":4,"EndTime":null,"EndQualifier":1,"EndQualifierUnit":"Days","Volcano":"Wrangell","ParentVolcano":"Wrangell","VolcanoID":"ak326","ParentVolcanoID":"ak326"},{"ID":333,"Name":"Augustine 1885","Description":"   According to Kienle and Forbes (1977) a mission report on May 27, 1885 stated: \"earthquakes still quite frequent here (Kenai?) and Chernabura is still smoking.\"  Becker (1898) says the volcano was steaming from shore to summit.\r\n   Waitt and Beget (2009) believe that this account describes rain or snowmelt infiltrating still-hot 1883 pyroclastic-flow deposits.","StartYear":1885,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":195,"Name":"Pavlof 1886","Description":"   Hantke (1955) reports a southern vent eruption from Pavlof in 1886.  Jacob and Hauksson (1983) report that this eruption was central, and produced \"red glares.\"  This red glare description is very similar to Becker's (1898) description of an eruption that he attributes to 1880.  (Perhaps there was only one \"red glare\" event - in 1880 or in 1886.)","StartYear":1886,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":237,"Name":"Akutan 1887","Description":"   Becker (1898) reported a lava eruption at Akutan in 1887.","StartYear":1887,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":453,"Name":"Kukak 1889","Description":"   Martin (1913) writes \"The easternmost volcano known on the Alaska Peninsula is Mount Kugak, which was probably active in 1889.\"\r\n   Wilson Fiske Erskine (1962) writes \"Kukak is supposed to have erupted as late as 1889 * * *.  The effects of Kukak's eruption on human life and civilization was relatively insignificant.  The area is a barren country and the eruption was minor compared to that of Katmai's.  Weather conditions at the time of Kukak's eruption also limited the area covered with volcanic debris.  In a few years all signs of Kukak's blast were obliterated.\"","StartYear":1889,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kukak","ParentVolcano":"Kukak","VolcanoID":"ak174","ParentVolcanoID":"ak174"},{"ID":399,"Name":"Wrangell 1890","Description":"   Sapper (1917) reports a \"silent eruption of fire\" at Wrangell in 1890.","StartYear":1890,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Wrangell","ParentVolcano":"Wrangell","VolcanoID":"ak326","ParentVolcanoID":"ak326"},{"ID":138,"Name":"Makushin 1891","Description":"   Becker (1898) reported steam from Makushin in 1891.  This activity probably does not constitute a volcanic eruption.","StartYear":1891,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":82,"Name":"Seguam 1891/12","Description":"   Jaggar (1927) reports Seguam \"broke into eruption for a week in December, 1891.\"  Coats (1950) classifies the eruption as a minor explosive eruption.","StartYear":1891,"StartMonth":12,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Seguam","ParentVolcano":"Seguam","VolcanoID":"ak246","ParentVolcanoID":"ak246"},{"ID":196,"Name":"Pavlof 1892","Description":"   Becker (1898) reports smoke from Pavlof in 1892.  Jacob and Hauksson (1983) report that eruption also produced \"fire\" at night from the summit.","StartYear":1892,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":83,"Name":"Seguam 1892/4","Description":"   Jaggar (1927, citation 1868) reports \"a terrific eruption in the spring of 1892, making detonations heard at the native village on Atka, 75 miles away, and exhibiting two jets of cauliflower clouds.\"\r\n   Jaggar (1927, citation 2639) reports Seguam in 1892 \"violently active, so that its eruption was seen from Nazan Bay [Atka] and the sky was darkened by the ash.\"\r\n   Presumably these reports refer to the same eruption from Seguam sometime during 1892, although 2 separate eruptions could have occurred.","StartYear":1892,"StartMonth":4,"StartDay":15,"StartTime":null,"StartQualifier":45,"StartQualifierUnit":"Days","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Seguam","ParentVolcano":"Seguam","VolcanoID":"ak246","ParentVolcanoID":"ak246"},{"ID":139,"Name":"Makushin 1892/7","Description":"   Cordeiro (1910) climbed Makushin in July 1892 and reported that the crater was smoking, and that there were yellow sulfur crystals being formed.  This activity may not constitute a volcanic eruption.","StartYear":1892,"StartMonth":7,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":238,"Name":"Akutan 1892/8","Description":"   From Stanley-Brown (1899): \"One unusually favorable day in August, 1892, Mr. Charles H. Townsend, of the United States Fish Commission, and I climbed one of the peaks of Unalaska bay, which brought Akutan in full view.  To our great surprise, we saw gigantic rings of smoke, such as sometimes come in miniature from the smokestacks of locomotives, issuing from the crater at regular intervals of about twenty minutes.  As each succeeding ring appeared, its predecessor was slowly breaking up and fading away in the air.  Four such rings were seen, but how long the display lasted it was not possible to determine, as the peak became obscured in drifting banners of fog.\"\r\n   Jacob and Hauksson (1983) additionally list that this eruption had explosions that were heard 30 miles away, plumes to 1000' feet high on September 23, and earthquakes.","StartYear":1892,"StartMonth":8,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1892,"EndMonth":9,"EndDay":23,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":308,"Name":"Veniaminof 1892/8","Description":"   Mount Veniaminof erupted explosively from Saturday, August 27, 1892 through Monday, August 29, 1892.\r\n   From Davidson (1892): \"From Captain Erskine, commanding the Alaska Commercial Company's steamer St. Paul, we learn that on Sunday, the 28th of August, 1892, when in latitude 53 degrees 05 minutes, longitude 155 degrees 52 minutes west, on his voyage to the Shumagin Islands, he passed through a black cloud of volcanic ash, so thick that it very nearly obscured the sun from 10 o'clock A.M. to 2 o'clock P.M.; the sea was grey with the fallen ashes, and his decks were covered during his passage of thirty-two miles through it.  It had a strong sulphurous odor. * * * At noon the vessel was 223 nautical miles southeastward of the volcano; the wind was moderately light from the northwest, and the sea smooth.  He estimated the cloud, as he saw it, to be about one hundred miles long, and from one-half to one mile high.  He has furnished us with a bottle of the fine, dark grey dust, as it was gathered from the vessel's deck.\r\n   \"Lieut. John C. Cantwell, of the U.S. revenue steamer Richard Rush, has given us the following memoranda, which he obtained from Captain Applegate, who has been many years in Alaskan waters, and whose vessel was, at the time of the eruption, anchored in the harbor of Ivanof.\r\n   \"On Saturday, August 27, 1892, the schooner Everett Hays, engaged in hunting in the vicinity of the Shumagin Islands, entered Ivanof Harbor, on the southwestern extremity of the Alaska Peninsula, and only 25 miles southwestwardly from the volcano.  Capt. J.S. Applegate, the owner, was on board, and states: 'About 10 o'clock Saturday night, the weather being calm and clear, a low, rumbling, intermittent sound was heard, and caused the crew to come on deck to ascertain the cause.  There was no surf, and the cause was unknown.  Between 11 and 12 o'clock, a dark cloud was observed in the sky, towards the northeast, and about 2 o'clock, A.M., this cloud had increased in volume and height until it covered the greater part of the northeast heavens.\r\n   \"'The low, rumbling noise had become a continuous roar, like the blast from a great furnace, and by 3 o'clock lurid flames could be seen amidst the smoke, which was now rising high in tremendous volumes from a single point, being by compass about northeast.  The vast column of smoke reached an estimated height of two miles, and then expanded like a great spreading oak.  From the lower edge of this great volume, colored flames waved like banners, and vivid flashes of lightning were apparently discharged into the base of the column.  This grand display continued, until daylight caused the flames to be somewhat dimmed, but masses of dense smoke continued to roll upward all Sunday.  Toward noon a light northwest wind sprang up, and the clouds began to trend to the southeastward, covering the mainland and the adjacent islands with a thick layer of ashes and volcanic dust.\r\n   \"'At the anchorage it was dead calm, and there was no perceptible movement of the sea on the beach, as would have occurred if there had been earthquake waves.  The continuous lightning discharges were accompanied by deafening peals of thunder, that were plainly heard at the Metrufan village, 50 miles distant, and at Unga Island, 75 nautical miles distant.'\r\n   \"Captain Applegate could not get the exact location of the volcano, on account of the high range of mountains, which here approach the sea.  The Hays left Ivanof Bay on Sunday, and steered south to Pavlof Island, whence the ash cloud was plainly visible to the eastward until late on Monday, when it gradually disappeared in the southeast.\r\n   \"Captain Bowles, of the fishing schooner Fremont, of San Francisco, reports that on Saturday, August 27th, and for seven days after, he was lying at anchor on Slime Bank, in the Bering Sea, in the vicinity of Port Moller, and 60 miles nearly west from the volcano.  He observed at the first date what appeared to be a heavy black cloud in the southeast, which he thought foreboded a southeast storm, and took precautions to put his vessel out of its track.  On Sunday morning before daybreak, however, he and his crew saw volumes of ruby red and yellow flames bursting forth with indescribable grandeur from the cloud, and heard plainly the reverberations of thunder.  The display lasted with unabated energy until Monday morning, when it appeared to die slowly away.\"","StartYear":1892,"StartMonth":8,"StartDay":27,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1892,"EndMonth":8,"EndDay":29,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Veniaminof","ParentVolcano":"Veniaminof","VolcanoID":"ak301","ParentVolcanoID":"ak301"},{"ID":285,"Name":"Cleveland 1893","Description":"   Jaggar (1927) writes that Cleveland was active in 1893.  More primary descriptions of this event have not been located.","StartYear":1893,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":334,"Name":"Augustine 1893","Description":"   From Cordeiro (1910): \"The island of Chernobura is reported as smoking.\"  Cordeiro does not specify when this \"smoking\" occurred, but says that most of his observations stem from his 1892 and 1894 cruises in Alaska.\r\n   Waitt and Beget (2009) believe this smoke was a lingering effect of the still-hot 1883 dome within the summit crater.","StartYear":1893,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":1,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":197,"Name":"Pavlof 1894","Description":"   Hantke (1955) reported a southern vent eruption from Pavlof in 1894.  McNutt (1985) reports \"fire\" at night during this eruption.","StartYear":1894,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":140,"Name":"Makushin 1895","Description":"   Becker (1898) reported steam from Makushin in 1895.  This activity probably does not constitute a volcanic eruption.","StartYear":1895,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":335,"Name":"Augustine 1895","Description":"   From Russell (1910): \"A slender cloud of steam ascended from the summit of the volcano, which seems to have been built up by eruptions of lapilli and dust since the explosion that rent it asunder.\"\r\n   Waitt and Beget (2009) believe this smoke was a lingering effect of the still-hot 1883 dome.","StartYear":1895,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":354,"Name":"Shishaldin 1895","Description":"   Becker reported steam at Shishaldin in 1895. However, Sapper (1917) points out that this notation of Becker's is identical to his remarks for Makushin, raising the possibility that this report is erroneous.","StartYear":1895,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":423,"Name":"Iliamna 1895","Description":"   From Russell (1910): \"In the summer of 1895, when last seen by Dall, it was sending out five or six parallel columns of steam, and seemed peaceful enough.\"   This statement is confusing, because Russell (1910) is referencing Dall, 1894, in Science, volume 3.  However, volume 3 of Science was published in 1884, and, although there is an article by Dall published in that issue, it does not discuss Iliamna.","StartYear":1895,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":1131,"Name":"Akutan 1895/8","Description":"A letter dated August 2, 1895, was printed in the August 30th, 1895 edition of the San Francisco Call: http://chroniclingamerica.loc.gov/lccn/sn85066387/1895-08-30/ed-1/seq-9.pdf . This letter describes an observation of Aktuan: \"A volcano on Akutan, a few miles west of here, is sending out great volumes of smoke, and it is doing a little in the way of belching out fire and lava. Last night we were close to it, and it was clear, a good view was had. I believe this is only periodically active, as I was in this vicinity last season and twice before that, but have not noticed so much smoke from it. There are five volcanoes within 100 miles, four of them at present active, or at least smoking.\"\r\nOn August 14, 1895, the Fish Commission Steamer Albatross reported \"Mt. Akutan in eruption.\" Logbooks transcribed by the Old Weather project give the ship's position as N 54 03' , W 166 40'. Scanned images of the relevant logbook pages are available here: http://oldweather.s3.amazonaws.com/ow3/final/Albatross/vol026of055/vol026of055_051_1.jpg and http://oldweather.s3.amazonaws.com/ow3/final/Albatross/vol026of055/vol026of055_051_0.jpg\r\nTranscription notes here: http://forum.oldweather.org/index.php?topic=3965.msg114333#msg114333","StartYear":1895,"StartMonth":8,"StartDay":1,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":239,"Name":"Akutan 1896","Description":"   Byers and Barth (1953) write that Akutan was \"glowing\" in 1896.","StartYear":1896,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":286,"Name":"Cleveland 1897","Description":"   Hantke (1951) reported Tanak-Angunak active in 1897.  Attempts to locate more primary descriptions of this eruption have not been successful.  Tanak-Angunak may refer to Carlisle rather than Cleveland.  From Miller and others (1998): \"Various names were applied to Carlisle on early hydrographic charts, including Uliaga, Kigalgin and variants thereof; it was also sometimes referred to along with the western half of Chuginadak Island, as Tanak-Angunak.  It is thus possible that some of the activity ascribed to Carlisle should be attributed to Uliaga or Mount Cleveland (Coats, 1950).\"  However, both Grewingk (1850) and Veniaminov (1840) give descriptions of Tanak-Angunak that define it as Cleveland.","StartYear":1897,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":355,"Name":"Shishaldin 1897","Description":"   Stanley-Brown (1899) reported that he saw \"what appeared to be banners of steam issuing\" from Shishaldin.","StartYear":1897,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":356,"Name":"Shishaldin 1898/4","Description":"   The April 29, 1898 logbook entry for the US Revenue Cutter Service vessel Bear reads, in part: \"Mid to 4 A.M. * * * 3:00 saw Shishaldin volcano in eruption, smoke and flames.\" Images of the logbook are available at the Old Weather project website: http://oldweather.s3.amazonaws.com/ow3/final/USRC%20Bear/vol079/vol079_164_1.jpg , http://oldweather.s3.amazonaws.com/ow3/final/USRC%20Bear/vol079/vol079_163_0.jpg , http://oldweather.s3.amazonaws.com/ow3/final/USRC%20Bear/vol079/vol079_164_0.jpg .\r\n   Stanley-Brown (1899) writes \"There are two very intelligent and well-to-do traders (Charles Rosenberg and Charles Swanson) who live with their families at Morshovia village, near the base of the mountain [Shishaldin].  While on a trip in their schooner to Dutch Harbor, Unalaska Bay, last summer [1898?] for supplies they told me that the volcano is now in a state of eruption, and that at night they had seen, high on the slopes, tongues of molten lava creeping slowly down the mountain side and branching around obstacles lying in their course, thus leaving islands between the fiery streams.  They asserted also that ashes are ejected from the crater, and that on hunting trips they had ascended far enough to detect the heat and recognize the sulphurous fumes.\"","StartYear":1898,"StartMonth":4,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":64,"Name":"Kasatochi 1899","Description":"   Jaggar (1927) writes that about 1899 the crater lake of Kasatochi disappeared and steam rose from the crater.","StartYear":1899,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":10,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kasatochi","ParentVolcano":"Kasatochi","VolcanoID":"ak146","ParentVolcanoID":"ak146"},{"ID":165,"Name":"Okmok 1899","Description":"   From Grey (2003): \"An explosive eruption is said to have occurred in 1899 (Dunn, 1908).  Robert Dunn (1908) details his visit to Umnak Island while 'vulcaneering' in the Aleutians.  After landing on the beach south of Cape Aslik [see figure 4.2 in original text], he hiked up the slope past Jag Peak to the top of the ridge (the WSW rim), where he first laid eyes on the caldera: 'Below, yawned simply one titanic crater, five miles from far side to far side, if one single inch.  Strewn on its floor, like toys perfectly carved, rose seven ash-cones; cones varied from symmetrical mounds that towered upon quite circular steep terraces, up to 500 feet and more, to the broken, chaotic black thing, like a big sand dump right under me.  And that was the living soul of the discovery.  Out of some vague cavern in its midst, undulated a column of white steam, a serpent-like Atlas, buoying the world's cloud cover.'\r\n   \"Dunn also observed the ash spread to the west and south of the caldera: 'The devastation reached between four and five miles from the crater edge.  This, of course, was the eruption of 1899.'  Judging from Dunn's description of his location and his map, his black 'sand dump' is likely Cone A, thus implicating the then undeveloped cone as the source of this event [see figure 4.3 in original text].  Dunn is the first white man known to recognize the existence of the caldera and name it.\"","StartYear":1899,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Okmok","ParentVolcano":"Okmok","VolcanoID":"ak206","ParentVolcanoID":"ak206"},{"ID":357,"Name":"Shishaldin 1899","Description":"   Coats (1950) reports Shishaldin smoking in 1899.","StartYear":1899,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":400,"Name":"Wrangell 1899/9","Description":"   From Motyka (1983): \"An eruption of Mount Wrangell, during the Icy Bay earthquake (magnitude 8.3) of September 4, 1899 was recorded by the chief quartermaster, and by the head guide of an expedition mapping the Copper Center region (Abercrombie, 1900).  Both men claimed they saw an eruptive plume over the summit and lava flowing down the northwest flank immediately following the earthquake.  Icy Bay is located 260 km southeast of Mount Wrangell.\"  The guide, A.M. Powell, reported that Mount Wrangell steamed profusely just after a great earthquake and continued to 'smoke with unusual animation for the rest of the season' (Abercrombie, 1900).\"\r\n   Miller and others (1998) write that \"Photographs of the ash covered summit of Mt. Wrangell that appear in the reports of Mendenhall and Schrader (1903) and Mendenhall (1905) may reflect an increase in activity following the September 3, 1899 Yakutat earthquake.\"","StartYear":1899,"StartMonth":9,"StartDay":3,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Wrangell","ParentVolcano":"Wrangell","VolcanoID":"ak326","ParentVolcanoID":"ak326"},{"ID":10,"Name":"Little Sitkin 1900","Description":"   Miller and others (1998): \"Evidence of more recent volcanism is provided by Snyder (1959), who mapped two dacitic flows on the south and west flanks of the crater that appeared no more vegetated at comparable altitudes than andesite flows produced during a well-documented 1906 eruption on Kanaga Island, 60 km to the west.  Snyder (1959, p. 183) argues that these extrusions 'are not older than' the 1906 Kanaga flows, implying that Little Sitkin has erupted at least once during the 20th century.\"","StartYear":1900,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":30,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Little Sitkin","ParentVolcano":"Little Sitkin","VolcanoID":"ak182","ParentVolcanoID":"ak182"},{"ID":401,"Name":"Wrangell 1900","Description":"   An article in the June 10, 1902 edition of the Galveston Daily News states \"In June, 1900, I observed a black patch several miles in extent on the southern slope of the mountain, extending from the summit down to perhaps 11,000 feet elevation.  As it was covered with snow when the mountain was next seen, about the last of September, it seems probable that the bare area was due to material thrown out by the volcano.\"  This report may not constitue a volcanic eruption, however, as a well-known fumarole patch on the southwestern flank of the volcano often appears as bare ground.\r\n   Richter and others (1995) report eruptive activity at Mt. Wrangell in 1900.","StartYear":1900,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Wrangell","ParentVolcano":"Wrangell","VolcanoID":"ak326","ParentVolcanoID":"ak326"},{"ID":198,"Name":"Pavlof 1901","Description":"   Powers (1953) reports an ash eruption from Pavlof in 1901.","StartYear":1901,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":358,"Name":"Shishaldin 1901/9","Description":"   Dunn (1906) reports an eruption from Shishaldin in September, 1901.","StartYear":1901,"StartMonth":9,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":84,"Name":"Seguam 1902","Description":"   Coats (1950) and Dunn (1906) report a suspected major explosive eruption at Seguam in 1902.  Miller and others (1998) and McGimsey and Miller (1995) report that this eruption occurred in 1901.","StartYear":1902,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Seguam","ParentVolcano":"Seguam","VolcanoID":"ak246","ParentVolcanoID":"ak246"},{"ID":336,"Name":"Augustine 1902","Description":"   From The Alaskan (1902): \"While Redoubt has been most active as regards recent volcanic eruption in Alaska, two other peaks in the Cook Inlet section have been thoring [sic] off smoke and steam in greater or less volume for several months.  They are Mount Iliamna and Mount Augustine.\"\r\n   From Johnston and Detterman (1979):  \"Coats quoted Sapper (1917), who told nothing more about the activity or about his source of information * * * Detterman (1973), who mapped the volcano after its 1963-64 eruption, referred to unpublished field notes of T.W. Stanton of the USGS, who visited the island July 17, 1904.  Those notes may have been the original source for Sapper's statement.\r\n   \"The only reference to activity in 1902 in Stanton's notes is contained in this brief passage: It is reported that * * * in 1902 there was a large 'mud flow' when one side of the crater broke off and slipped down, according to A. Brown who says he witnessed it from the mainland.\"\r\n   Johnston and Detterman (1979) state that there was no eruption in 1902, based on 1) their inability to find a primary reference to activity at Augustine, 2) photographs taken in 1895 and 1904 seem to show no change to the summit crater, 3) ash layers are found in Skilak Lake for every historic Augustine eruption except the 1902, and 4) they found no 1902 ash layer on Augustine Island.  A primary eruption reference (The Alaskan newspaper) has now been located - which suggests that perhaps a minor eruption, too small to modify the summit crater or deposit long-lasting ash layers, did occur.  It is also possible that there was no eruption, and Augustine was merely experiencing an increase in fumarolic activity.","StartYear":1902,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":437,"Name":"Redoubt 1902/1","Description":"   From the Daily Alaska Dispatch (1902): \"Word has just been received that Redoubt, one of the volcanoes at Cook's Inlet had an eruption on January 18, and the country for 150 miles around was covered with ashes and lava.  The news comes from Sunrise, but nothing definite has been ascertained as to whether any damage was done, for no boats have as yet been in the neighborhood of the volcano.\r\n   \"On the date of the eruption the sky was darkened and at Sunrise, the snow was covered so thick with sand and ashes that it was impossible to do any sledding until a fresh fall of snow.  At Hope, 12 miles distant [from Sunrise], the ashes were half an inch thick, and at Knik, on the opposite side of the Inlet was still deeper.  These towns are about 150 miles northeast of the volcano [note: these towns are actually less than 100 miles from Redoubt], and the terrible force of the eruption can be imagined.\"\r\n   From The Alaskan (1902): Information has reached Juneau that sometime about New Year's day a terrific volcanic eruption occurred not far from Kenai on Cook's Inlet about 70 miles above English Bay.  After the eruption, or during the time there was a terrific earthquake which burst the mountain asunder leaving a large gap, and the flames could be plainly seen from the village.  The ground at the town of Kenai was covered with ashes and subsequently a tidal wave came in which did much damage.  The water in the inlet rose to a great height and terror reigned throughout the village.  The mountain was still smoking at the time the letter was written and occasionally large quantities of lava thrown there from.  The letter bringing this information is from the Russian Priest at Kenai, who at one time resided here in Juneau.\r\n   \"The Excelsior did not stop here going down and consequently the information which was sent here did not arrive until the return of the boat. \r\n   \"The steamer at this time of year cannot make Kenai and the letter was brought out to the nearest office by a native.  The Discovery will undoubtedly have fuller particulars. -- Record Miner.\"\r\n   A May 31, 1902 Associated Press article indicates the eruption continuing: \"Mount Redoubt, in the Cook Inlet country, has been pouring out dense volumes of smoke for over a week and a few nights ago spouted out flames.  The natives are greatly terrified and many have sought safety in flight to the farther end of Kensi peninsula.  For several days volcanic ashes have been falling.  The snow for many miles in every direction from Mount Redoubt is covered with ashes and Montague Island, in Prince William's sound, is also covered.  Explosions and rumblings in the interior of the mountain are heard almost constantly and earth tremblings are of common occurrence.\"\r\n   The eruption continued to be listed in newspaper accounts.  From June 3, 1902: \"Passengers from Cook's Inlet, who arrived [to Seattle] by the steamer Chico confirm the previous rumors of another eruption of Redoubt volcano.  The ship's course out of Inlet left the volcano directly to the westward, at which point is looked as if a continuous sheet of fire was rising probably miles high.\"  A very similar, but less dramatic, article was published June 3, 1902, in the Galveston Daily News: \"Passengers from Cook Inlet, who arrived [to Seattle] by the Chico, confirm previous rumors of another eruption of Redoubt Volcano, which is situated on the west side, about 40 miles northwest of Iliamna.  Among them was A.C. Losey of Tacoma, who has been in the employ of the Translaska Company, and who saw the present eruption.  Dense black clouds covered the entire region, spreading over Cook Inlet.  At times the smoke directly over the volcano region were likened to a dark gray, but no flames were seen and no ashes reached the ship, but in the evening bright flashes flared up and lighten the whole sky in that region.\"\r\n   Juergen Kienle collected the following information from Brooks' scrapbook: \"May 3, 1902, Redoubt - late June, the smoke and clouds were so dense that one couldn't see, June 21, 1902 - Kotzina locality - great clouds of black smoke.  Lava in creek beds.\"\r\n   Till and others (1993) summarize the eruption as follows: \"In 1902, explosive eruptions of Redoubt deposited tephra from Lake Clark to the Skwentna valley (Martin and Katz, 1912).  Tephra fell on the settlement of Hope on the Kenai peninsula, January 22 and repeated explosions were heard there February 17 and 18 (The Alaskan, Sitka, March 29, 1902).  An English tourist reported that 'at Kenai and Kusiloff [Kasilof] * * * [tephra] lay on the ground several inches thick in places' (Cane, 1903).  This is probably an exaggeration, because there is no sign of 1902 tephra in terrestrial sites or in lake cores near Kasilof or Kenai (Thomas Ager, written commun., 1985).  Tephra deposits from this eruption have been recognized elsewhere, however, and an analysis of tephra from this eruption was published by Pulpan and Kienle (1979).\"  Pulpan and Kienle (1979) state that the tephra is andesite.","StartYear":1902,"StartMonth":1,"StartDay":18,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1902,"EndMonth":6,"EndDay":21,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Redoubt","ParentVolcano":"Redoubt","VolcanoID":"ak231","ParentVolcanoID":"ak231"},{"ID":402,"Name":"Wrangell 1902/6","Description":"   From Motyka (1983): \"Mendenhall (1905) reported sighting at least a dozen fumarole plumes along the western caldera rim of Mount Wrangell during the summer of 1902.  A photo in Mendenhall's report, taken in late May or early June 1902, shows a vapor plume over the West Crater and the snow around it covered with ash.  An article in the July 1, 1902 edition of the Valdez Prospector stated that large black clouds were billowing above Mount Wrangell's summit, and volcanic debris was floating down the local streams.\"\r\n   An article in the June 10, 1902 editon of the Galveston Daily News reported that Mount Blackburn was \"in active eruption.\"  The unlisted author of the article states that volcanic activity at Blackburn is \"improbable\" and focuses instead on Mount Wrangell.","StartYear":1902,"StartMonth":6,"StartDay":null,"StartTime":null,"StartQualifier":2,"StartQualifierUnit":"Months","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Wrangell","ParentVolcano":"Wrangell","VolcanoID":"ak326","ParentVolcanoID":"ak326"},{"ID":558,"Name":"Pavlof 1903/6","Description":"   Robert Dunn (1906) lists an \"outbreak of more than average violence\"  from Pavlof in summer, 1903.  He does not list an event at Pavlof for 1901.  He also states that Pavlof \"which generally steams actively, ceased to do so in the spring of the present year\" [1906].","StartYear":1903,"StartMonth":6,"StartDay":null,"StartTime":null,"StartQualifier":2,"StartQualifierUnit":"Months","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":781,"Name":"Shishaldin 1903/6","Description":"The July 30, 1903 logbook entry for the US Revenue Cutter Service vessel Bear reads, in part: \"8 P.M. - Mid. Partly clear, moderate to very fresh S.S.E. breeze choppy sea. Observed gas flames from Shishaldin. ?? S.S.W. 1/2 W. steam alone. Images of relevant pages from the logbook are available at the Old Weather project website: http://oldweather.s3.amazonaws.com/ow3/final/USRC%20Bear/vol088/vol088_066_0.jpg and http://oldweather.s3.amazonaws.com/ow3/final/USRC%20Bear/vol088/vol088_066_1.jpg .","StartYear":1903,"StartMonth":6,"StartDay":30,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":39,"Name":"Kanaga 1904","Description":"   Jaggar (1927) writes that Kanaga was \"very active\" in 1904.  Coats (1950) speculates that the southern flow on Kanaga was perhaps emitted in 1904 from the upper south flank.  Miller and others (1998) combine this 1904 eruption with the 1906 eruption as one event.","StartYear":1904,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kanaga","ParentVolcano":"Kanaga","VolcanoID":"ak144","ParentVolcanoID":"ak144"},{"ID":50,"Name":"Great Sitkin 1904","Description":"   From Jaggar (1927): Great Sitkin fuming in 1904.  Coats (1950): Great Sitkin smoking in 1904.","StartYear":1904,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":199,"Name":"Pavlof 1906","Description":"   Jaggar (1929) writes that an island trapper reported that between 1906 and 1911, Pavlof smoked vigorously, and \"sometime in 1911 'fire' poured down the mountain and alarming rumbles continued for several months.  Bowlders were thrown into the air.  The mountain was reported to have cracked open toward the north, * * * observers on the island of Unga report that an alarming roar was heard, waxing and waning, on the night of December 6-7 1911, between 8pm and 4am, and that the noises were heard for four days.  A series of earthquakes was recorded on December 31, 1911 at 12:45, 6, and 7:15am, and at 8:45 pm at Unga.\"  Unga is approximately 55 miles away from Pavlof.\r\n   McNutt (1985) writes that this is the most powerful historic eruption of Pavlof.","StartYear":1906,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1911,"EndMonth":12,"EndDay":7,"EndTime":null,"EndQualifier":4,"EndQualifierUnit":"Days","Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":115,"Name":"Bogoslof 1906/3","Description":"   The Smithsonian Volcanoes of the World book and the Global Volcanism Program online database considers the time period between March, 1906, and September, 1907, to be one eruption at Bogoslof.  However, the GeoDIVA database has separated the formation and destruction of Metcalf Cone (March, 1906-January, 1907) as one eruption, and the formation and destruction of McCulloch Peak (January 1907-September 1907) is treated as a separate eruption.\r\n   From Miller and others, 1998: \"In 1906, a dome bearing a broken spire at its summit appeared midway between Old and New Bogoslof.  This structure, called Metcalf Cone, exploded in late 1906 or early 1907, destroying its southern extent.\"  Lieutenant-Commander Garrett first saw Metcalf Cone, and proposed for it the name Metcalf Cone.  \r\nOn July 10, the USRCS Thetis \"reconnoitered Bogoslof\" and reported \"* * * observed that a new island had sprung up between the two old ones, about 1/3 of the distance from the first one (which came up in 1801) to the second (1881) and connected to the first one by a ridge of land; a long spit runs out form the Southern end of the new island, just as one runs from each of the others. A crater pouring, firth vapor, is opened on the North side about 3/4 of the way up, and all around the island, vapor is spurting up through fissures, and the vapor is so thick over the surface of the island that it looks like bank of snow. There is no indication of boiling water, reported by Dirks, around the island. Sounded in 175 fms of water, within in three miles of the island, showing no general upheaval, but the water appears to be shoaler between the islands than it formerly were.\" These logbook pages are viewable at http://oldweather.s3.amazonaws.com/ow3/final/USS%20Thetis/vol610/vol610_040_0.jpg and http://oldweather.s3.amazonaws.com/ow3/final/USS%20Thetis/vol610/vol610_040_1.jpg .\r\nLater, members of the S.S. Perry saw the same structure, and, not knowing of Garrett's previous name for it, called it Perry Peak.\" Logbooks from the US Revenue Cutter Service Perry are available at \u003ca target=\"_blank\" href=\"http://www.oldweather.org/ships/523c928e68f4b82a89000002\"\u003ehttp://www.oldweather.org/ships/523c928e68f4b82a89000002\u003c/a\u003e. The July 29, 1906 sighting is recorded on this page: http://oldweather.s3.amazonaws.com/ow3/final/Commodore%20perry//Volumes/Seagate%20Backup%20Plus%20Drive/Arfon-JPEGS/RG26/COMMODORE%20PERRY//vol183/vol183_026_1.jpg .\r\n   Jaggar (1908) states that the activity began in March, 1906, and summarizes various accounts and articles of this eruption as follows: \"Lieutenant-Commander Garrett, U.S.N., reported that the Albatross reached the Bogoslof Islands May 29, 1906, and found a steaming new cone midway between the two older islands.  It was connected with Grewingk by a low flat ridge, but separated by a channel from Castle Rock.  This channel was later sounded by officers of the Revenue S.S. Perry, and seven fathoms were reported.  Garrett wrote: 'The new land is conical in appearance, and consists of a mass of eruptive rocks, among which traces of sulphur are plainly visible.  It possesses no distinct crater, but numerous vents among the rocks, from which volumes of steam issued.'  The summit showed a broken horn bending to the northeast, 'as though the mass had been forced up through an aperture while in a plastic condition, the sides being quite smooth.'  This horn proved a remarkable feature, and the key to the whole structure.    \r\n   \" * * * Garrett's suggestion of a rising plastic mass was correct.  He proposed for the new hill the name 'Metcalf Cone' in honour of Secretary Metcalf.\r\n   \"Mr. Robert Dunn visited the new cone in a schooner in July, 1906, and climbed the new peak.  He saw that the pudding-like cone had a solid rock core, and that the salt-water lagoon which half encircled it on the north had a temperature varying from seventy to ninety degrees.  There was no noise.  The pinnacle on the summit was like a great parrot's beak, rounded and smooth on the west, but making an overhanging cliff forty feet high on the east.  The steam-vents gave temperatures varying from 94 to 212 degrees, and the hottest vent, at the foot of the parrot cliff, was adjacent to rock practically incandescent, for here a piece of paper burst into flame.  The top of the spine was about 390 feet above sea-level by pocket barometer.\"\r\n   Jaggar (1930) states that \"at the beginning of 1907 Metcalf Cone was broken in two, while the channel between it and Castle Rock had filled itself with a new steaming heap of lava.\"\r\n   Newhall and Melson (1983) estimate that the volume of the Metcalf, McCullogh, and Tahoma Peak lava domes (1906-1910) was about 5x10^6 cubic meters.  Simkin and Siebert (2002-) estimate a tephra volume of 5.1 +/- 5.0 x 10^8 cubic meters, based on Sapper's (1927) classification.","StartYear":1906,"StartMonth":3,"StartDay":null,"StartTime":null,"StartQualifier":1,"StartQualifierUnit":"Months","EndYear":1907,"EndMonth":1,"EndDay":null,"EndTime":null,"EndQualifier":3,"EndQualifierUnit":"Months","Volcano":"Bogoslof","ParentVolcano":"Bogoslof","VolcanoID":"ak29","ParentVolcanoID":"ak29"},{"ID":40,"Name":"Kanaga 1906/5","Description":"   From Miller and others (1998): \"A trapper living on the island in 1906 experienced several earthquakes and witnessed lava pouring down both east and west sides of the cone.  Coats (1956) interpreted these flows to be the ones now present on the northeast and southwest slopes of Kanaga Volcano.\"\r\n   Coats (1956): \"An eruption in May 1906 was reported in a letter to the writer from Simeon Oliver, teacher at Atka, who obtained his information from William Dirks of Atka.  According to Dirks, who was trapping near Kanaga Volcano at the time, earthquakes occurred and lava poured down the east and west sides of the cone to the sea.  It is possible that these lava flows are the ones  now present on the southwest and northeast sides of the cone; however, only one of them reached the sea.\"","StartYear":1906,"StartMonth":5,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kanaga","ParentVolcano":"Kanaga","VolcanoID":"ak144","ParentVolcanoID":"ak144"},{"ID":1,"Name":"Kiska 1907","Description":"   Coats (1950) reported \"smoke\" was observed over Kiska island in 1907.  \r\n   Miller and others (1998) summarizes from Coats (1961):  \"Coats briefly visited Kiska volcano in 1947 and found no evidence of recent ash flows nor any active fumaroles; the youngest lava flows were more heavily vegetated at any given altitude than counterparts on adjacent islands known to have been erupted in the 20th century.  The youngest lava flows before 1962 were probably between 100 and several hundred years old.  Coats concluded that any events between 1905 and 1947 were at most solfataric.\"","StartYear":1907,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kiska","ParentVolcano":"Kiska","VolcanoID":"ak161","ParentVolcanoID":"ak161"},{"ID":68,"Name":"Korovin 1907","Description":"   Eakle (1908) reported \"dense clouds of vapor\" from the summit of Korovin.  Jaggar (1927) reported \"fresh volcanic cinder\" on the snowfields near Mt. Kluichef during the same year, and a boiling spring.  Hot springs and fumaroles are well-known in the vicinity of Korovin and Kliuchef, and this report may be nothing more than the usual fumarolic and hydrothermal activity.","StartYear":1907,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Korovin","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak171","ParentVolcanoID":"ak17"},{"ID":240,"Name":"Akutan 1907","Description":"   A March 15, 1907, Washington Post newspaper article describes the eruption observed in March, 1907: \"Word has been received from Valdez, Alaska, that the volcano on the Island of Akutan, off the Peninsula of Alaska, and not far from Unalaska, was in active eruption when the steamer Dora passed the island at 2 a.m. on February 28.  All the passengers were aroused to witness the sight, which is said to have been magnificent.\r\n   \"At about the same hour, a severe earthquake occurred occurred at Unalaska, although it did no serious damage.\"\r\nThe U.S. Revenue Service Cutter Perry reported Akutan 'emitting considerable smoke' on June 21, 1907. (Logbook entry available on Old Weather project website: http://oldweather.s3.amazonaws.com/ow3/final/Commodore%20perry//Volumes/Seagate%20Backup%20Plus%20Drive/Arfon-JPEGS/RG26/COMMODORE%20PERRY//vol184/vol184_175_1.jpg ).\r\n   Jaggar (1908) reports that on June 28, 1907, the \"lower active cone of Akutan near the shore is throwing up columns of black factory 'smoke' - steam charged with dust.  Continues to say that on the slopes and in the gulch descending from the crater there is much snow, soiled with new-fallen volcanic dust\" and on July 3, 1907, Akutan was smoking, and they observed 4 black puffs.\r\n   Eakle (1908) writes: \"Last summer Akutan was sending up intermittently a huge column of vapor, which spread out above into the well known cauliflower or umbrella shape, similar to the smoke column that hung over San Francisco during the recent conflagration.\"\r\n   And Finch (1935) states that \"In 1907 the volcano was more or less continuously active for most of the year.\"","StartYear":1907,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":571,"Name":"Kliuchef 1907","Description":"   Jaggar (1927) reported \"fresh volcanic cinder\" on the snowfields near Mt. Kliuchef during 1907, and a boiling spring.  Whether the \"fresh volcanic cinder\" came from Korovin or Kliuchef is uncertain.","StartYear":1907,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kliuchef","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak164","ParentVolcanoID":"ak17"},{"ID":116,"Name":"Bogoslof 1907/1","Description":"   The Smithsonian Volcanoes of the World book and Global Volcanism Program online database considers the time period between March, 1906, and September, 1907, to be one eruption at Bogoslof.  However, the GeoDIVA database considers the formation and destruction of Metcalf Cone (March, 1906-January, 1907) one eruption, and the formation and destruction of McCulloch Peak (January 1907-September 1907) is treated as a separate eruption.\r\n   Miller and others (1998) summarizes this eruption, which began in early 1907,  as follows: \"[A]nother dome emerged, joining Metcalf Cone and Old Bogoslof (Byers, 1959).  This dome, McCulloch Peak, was subsequently obliterated in a violent explosion on September 1, 1907 that showered Unalaska Village with 0.5 cm of ash and mantled the remaining Bogoslof Islands with debris.\" The Perry likely saw McCulloch Peak on June 21, 1907, as they recorded in their logbook \"Some unfamiliar pinnacle rocks between Castle and Perry Islands\" (see logbook entry on Old Weather website: \u003ca target=\"_blank\" href=\"http://oldweather.s3.amazonaws.com/ow3/final/Commodore%20perry//Volumes/Seagate%20Backup%20Plus%20Drive/Arfon-JPEGS/RG26/COMMODORE%20PERRY//vol184/vol184_175_1.jpg\"\u003ehttp://oldweather.s3.amazonaws.com/ow3/final/Commodore%20perry//Volumes/Seagate%20Backup%20Plus%20Drive/Arfon-JPEGS/RG26/COMMODORE%20PERRY//vol184/vol184_175_1.jpg\u003c/a\u003e.\r\n   Jaggar (1908) reports: \"In the spring of 1907 Captain Dirks, a local trader, brought word that a still newer peak had risen beside Metcalf Cone.  The Cutter McCulloch visited the scene in July, 1907, and reported that this was indeed true, and moreover, Metcalf Cone had half collapsed, and the channel between it and Castle Rock was filled up with the new steaming heap, \"McCulloch Peak,\" and a wide stretch of gravel wash.  Such was substantially the state of affairs when the Technology Expedition arrived August 7, 1907.  A day was spent in exploring, photographing, and collecting specimens.  The landing was made in dories in the midst of a herd of roaring sea-lions.\r\n    \"* * * As a land mass above tidewater it was a continuous island about two miles long, with the new steaming cones in the middle 400 to 500 feet high.  Grewingk, flat-topped and cliff-encompassed, guards the north end of the island, while Castle Rock, pinnacled and jagged, rises on the south.  The intervening spaces were filled with sand, gravel, and volcanic bombs, making wave-washed bars ten or twelve feet above sea-level.  It was unbelievable that only sixteen months ago there was nothing there, between the north and south islets, but open water, and some ten fathoms of that!\r\n   \"* * * All the pinnacles of Castle Rock were sharpened between 1906 and 1907 - probably by the bombardment of falling stones and sand at the midwinter season when a violent explosion broke Metcalf Cone in twain.  There are marks of flood-waves and bombs and pumice on the flats, which give good reason for the belief that the moment which ended the life of Metcalf Cone and began that of McCulloch Peak, in the winter of 1906-07, was explosive.\"\r\n   Jaggar (1908) estimates that old Castle Rock rose about twenty-five feet during the past eight months, and McCulloch Peak was over 400 feet high with a base of nearly 2000 feet across at sea-level.  While Jaggar was at Bogoslof (August, 1907) the volcano was nearly enclosed by a lagoon of 90 degree salt water.  McCulloch peak was steaming, and larger vents were coated in sulfur.  Metcalf Cone was a sheer face of rock descending to the waters of the hot lagoon on the McCulloch side, and was about 400 feet wide with a 360 foot-wide base.\r\n   Jaggar (1908) further reports: \"On September 1, twenty-four days after the Technology Expedition left Bogoslof, the natives, traders and revenue officers who live at Iliuliuk saw toward the west a dense black cloud rising and the air was full of sulfur fumes.  About five o'clock in the afternoon ash and sand began to fall, followed by rain and distant rumbling.  A quarter-inch layer from this snowstorm of sand settled on roofs and shipping and grassy landscape, making all appear wan and drooping with a monotonous gray mantle.\r\n   \"The Cutter McCulloch * * * visited Bogoslof [in October] and [found] McCulloch Peak absolutely gone, a steaming lagoon in its place, and the rest of the island piled high with fallen debris.  The half of Metcalf Cone was still 'standing in grim silence as a headstone at the grave of the departed peak.'  The north slope of Metcalf showed the smooth cone curve, concave in profile upward, so characteristic of cinder-cones like Fuji or Vesuvius, and this marked for Bogoslof one more step in the cone-building process.\"\r\n   Newhall and Melson (1983) estimate that the volume of the Metcalf, McCullogh, and Tahoma Peak lava domes (1906-1910) was about 5x10^6 cubic meters.","StartYear":1907,"StartMonth":1,"StartDay":null,"StartTime":null,"StartQualifier":3,"StartQualifierUnit":"Months","EndYear":1907,"EndMonth":9,"EndDay":1,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Bogoslof","ParentVolcano":"Bogoslof","VolcanoID":"ak29","ParentVolcanoID":"ak29"},{"ID":405,"Name":"Wrangell 1907/4","Description":"   From Crosby (1907): \"To the editor of Science: Mr. Arthur P. Porter, civil engineer and graduate of the Massachusetts Institute of Technology, writing from Elliott Creek, Alaska, under date of May 24, 1907, communicates the following interesting observations:  \r\n   \"On and about April 5, several mountains of the Wrangell range in Alaska were active volcanically, sending up great clouds of steam and causing a flood in the Kotsina River that, on April 6, came down past our camp at the mouth of the Kotsina, cut us off from our supply train and prevented our going up the Kotsina on the ice. \r\n   \"To go more into detail, the first we heard about it was on April 1, when we were mushing down the Tonsino River.  We stopped for dinner at the camp of some freighters hauling in supplies for the Hubbard-Elliott mine; and Mr. Hubbard said that they could plainly see the smoke (?) rising from Mt. Wrangell.  That afternoon and the following day, as we proceeded down the Tonsino and then down the Copper River, we caught occasional distant views of the mountains, but I noted nothing remarkable.  (A photograph taken April 2 shows the mountains clear.)  On April 5 and 6 we saw great white clouds which always rolled away from the mountains, yet never left them clear; and with the field glasses steam was seen issuing from the sides of the mountains below the tops.  We were at the mouth of the Kotsina, about forty miles from the mountains, and could not positively identify the peaks.  Apparently, however, Mts. Wrangell, Blackburn, and Sanford were all sending up steam.\r\n   \"The next day, April 6, a sudden flood came down the Kotsina on top of the ice and underneath it.  There had been no warm weather and no rain (28 degrees below zero instead).  The flood lasted two days and then went down.  The enclosed photograph [not published] shows the head of the flood advancing down the river and spreading over the snow as it came.  I stepped on an ice hummock to take the picture; and by the time I could focus my camera, the flood had passed me on both sides and nearly cut me off.  The toe of the flood advanced at the rate of fifty feet a minute, actual timing, eating its way through the snow as if the water were warm.\r\n   \"May 28, the mountains seem to be steaming again (Mt. Drum or Mt. Sanford), and others noted the same two days ago.\"","StartYear":1907,"StartMonth":4,"StartDay":1,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Wrangell","ParentVolcano":"Wrangell","VolcanoID":"ak326","ParentVolcanoID":"ak326"},{"ID":141,"Name":"Makushin 1907/7","Description":"   Jaggar (1908) climbed Makushin on July 3, 1907 and reported: \"The rim of the crater was finally reached at 12:45.  Within was an expanse of snow, probably two miles in diameter, through which three or four steaming vents have maintained openings.  Here we encountered fog and rain lifting and closing at intervals.  We saw a steaming cavity ahead to the right.  Examination proved this to be a new crater opening which was unknown to the guide, therefore it was promptly named the \"Technology Crater\" of Makushin.  It is a vertical cavity in the snow, 75 feet in diameter, with a 300-foot wall of bedded ice and snow behind it and sulphurous steam incessantly rising through it.  A great tumble of snow or ice blocks rests in front of it, and, where the steam drifts across these, their white surfaces are yellowed with sulphur.\"  This crater is located between the central cone and the north rim of the caldera.\r\n   He also reported that the larger crater of Makushin contained very active solfataras on its northern side, and they also found a 15-foot diameter area of boiling mud.\r\n\r\nThe logbook of the USS Thetis (then the US Revenue Cutter Service Thetis) also records an eruption from Makushin during 1907. On Sept 1, 1907, they were anchored in Unalaska, and wrote \"Between 5-00 and 5-30, heard two distinct explosions supposed to be from Makushin volcano. At 5-30, a thick shower of cinders and ashes from Mt. Makushin swept over the harbor and continued until 6-30, when light rain set in. Vessel covered with thin coat of cinders and ashes. Washed down decks and paint work. At 8-00, light shower of ashes from volcano again swept over harbor continued generally until midnight.\" The logbook record is viewable at the OldWeather project: https://oldweather.s3.amazonaws.com/ow3/final/USS%20Thetis/vol612/vol612_069_1.jpg \r\nAs the weather for that day was recorded as east-south-easterlies all day, their supposition that the eruption originated from Makushin is the most likely. Thank you to the OldWeather project for transcribing this logbook and notifying AVO of the eruption account.","StartYear":1907,"StartMonth":7,"StartDay":3,"StartTime":"12:45:00","StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":117,"Name":"Bogoslof 1908/1","Description":"   In July, 1908, observers on the vessel McCulloch reported that Metcalf Cone of the Bogoslof Islands was completely gone (Jaggar, 1930).  This observation suggests that there was an explosive eruption during the winter of 1907-08.  Possible evidence of this eruption was witnessed by observers on the Albatross early in the year of 1908.\r\n   From Hunnicutt (1943): \"The crew of the U.S.S. Albatross in 1908, while traveling off the islands, witnessed an uprising of a subterranean volcano which doubtless later added to the bulk of Bogosloff.  The surface of the ocean rose in a gigantic, dome-like swelling, suggestive of a colossal soap bubble, then receded.  This occurred several times and before each subsidence there was a tremendous escape of gas.  Gigantic clouds of smoke and steam issued from where the water had humped itself.\"","StartYear":1908,"StartMonth":1,"StartDay":null,"StartTime":null,"StartQualifier":3,"StartQualifierUnit":"Months","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Bogoslof","ParentVolcano":"Bogoslof","VolcanoID":"ak29","ParentVolcanoID":"ak29"},{"ID":241,"Name":"Akutan 1908/2","Description":"   Sapper (1917) reports Akutan in eruption on February 22, 1908.  Coats (1950) says this eruption also had a lava flow. The US Revenue Cutter Perry reported Akutan \"smoking\" on September 22, 1908.","StartYear":1908,"StartMonth":2,"StartDay":22,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":341,"Name":"Augustine 1908/3","Description":"   From the Seward Daily Gateway (1908): \"On the night of the 10th inst. as Captain Z. Moore of the steamer Dora was making his return trip from Unalaska to Seward, he saw in the distance what seemed to be fireworks on a very extensive scale.  Immediately taking his bearings the captain found he was 63 miles off Chonobora island and the flames which lighted the heavens above came from the previously long extinct volcano St. Augustine.  As the molten mass within the mountain was thrown up by internal forces on the earth, the outer crust was parted and the red glow of the melted mass cast its lights far upward on the smoke and clouds above.  This was followed by intervals of darkness caused by the subsidence of the volcanic action.  Then again the heaven above would glow with the reflection of the light from earth's mighty furnace making as fine a display of nature's fireworks as has ever been seen in this part of the world.\"\r\n  Waitt and Beget (2009) describe this as \"a minor burst of molten lava.\"","StartYear":1908,"StartMonth":3,"StartDay":10,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":443,"Name":"Wrangell 1908/7","Description":"   From Motyka (1983): \"Mount Wrangell was climbed in July 1908 by R. Dunn and W. Soule.  Dunn (1909) reported considerable venting of vapor from the depths of the West Crater with plumes rising from 2 to 3 km above the crater.  All that was visible of the North Crater were the peaks located on the west rim, the remainder of the crater apparently being snow covered.\"","StartYear":1908,"StartMonth":7,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Wrangell","ParentVolcano":"Wrangell","VolcanoID":"ak326","ParentVolcanoID":"ak326"},{"ID":118,"Name":"Bogoslof 1909/9","Description":"   Miller and others (1998) summarizes the September 1909-1910 eruption of Bogoslof as follows: \"Yet another conical islet, Tahoma Peak, was formed during the winter of 1909-1910 in the bay created by the destruction of McCulloch Peak.  Explosions in September of 1910 produced a deep crater at its summit (Byers, 1959); this was apparently the first documented crater in a Bogoslof dome (Jaggar, 1930).\"\r\n   Powers (1916) relates the following detailed information: \"Renewed activity in the bay between Old Bogoslof and Fire Island is reported in September, 1909.  The bay had closed to form a lagoon, in which two small islands had risen, once of which gave off steam.  The water in the lagoon was also constantly steaming.  The two small islands were apparently just beginning to rise as new rocky spines, for on June 16, 1910, they are reported to have united and risen to a height of 178 feet above the lake level.  Old Bogoslof, Fire Island, and the southwest shore of the lagoon remained the same as in the preceding year, but the new spines had become connected with the northeast shore of the lagoon, and a portion of the shore on that side had risen ten feet.  Although the temperature of the salt lagoon ranged from 62 degrees to 100 degrees F., there was little activity in the new rock-masses and water was boiling up from only a few places near the lagoon.\r\n   \"A survey of Bogoslof Island was made on September 10, 1910, under the direction of Captain J.H. Quinan of the U.S. Revenue Cutter Tahoma, showing that the island was about one and a half statute miles long and three-quarters of a mile wide, as shown in Figure 2.  The elevations of the peaks were: Fire Island, 175 feet, Castle Rock (Old Bogoslof), 289 feet; the higher of the two central peaks, 178 feet; the lower, 100 feet.  The lower of the central peaks is given the name Tahoma Peak by Captain Quinan in his report, and the higher is called Perry Peak in spite of the fact that the remaining portions of Perry Peak were reported to have disappeared by July , 1908.  [There is some discrepancy about when Perry Peak disappeared; Powers says by July, 1908, while other sources say it disappeared by September, 1908]  In view of the records given above, it seems probable that Captain Quinan saw a new peak which rose in 1909-10 in the same place that Perry Peak occupied from 1906-08.  No name is suggested for this new peak.\r\n   \"Steam issued from the base and sides of the new peaks at the time of the visit, and steam was issuing from the salt lagoon shown on the map.  Between the new peaks and Fire Island, in the mud-covered area near the small lagoon, an area of several hundred yards was in violent agitation.  Boiling water was being ejected through the mud, and in two pools, each about four feet in diameter, water was being thrown to a height of five feet by the rapidly escaping steam.  Another seat of activity was on the northeast side of Tahoma Peak, at the edge of the main lagoon.  Explosions had recently taken place here, according to Captain Quinan's report, and a group of steaming conical rocks had risen since the explosion.  The water around these rocks was boiling, but not so violently as near the smaller lagoon.\r\n   \"* * * [F]ortunately Captain Quinan sailed back toward the island on September 18, and when about twenty-five miles away in the early morning witnessed an eruption.  Forked lightning in the direction of Bogoslof was seen before daylight, and when Bogoslof was sighted the new central peak was seen to be in a state of eruption.  Immense clouds of vapor, smoke, and ashes issued from the peak and enveloped the entire island.  Flames were reported at the peak, and lightning followed by thunder appeared in the cauliflower cloud of smoke and volcanic dust which rose to a height of several thousand feet above the island.  The eruption lasted during the several hours the steamer remained in the vicinity, and two days later the central peak was observed to be still steaming.\r\n   \"The eruption of September, 1910, seems to have opened a true crater in the top of the central peak - the first important crater which has been reported on any of the masses of very viscous rock which have been slowly pushed out from the top of the submarine volcano to form the \"rocks' and \"peaks\" of the last hundred and fifty years.\" \r\n   Hunnicutt (1943) reports more colorfully on the experiences of Captain Quinan and his crew, stating \"the Tahoma experienced a violent electrical storm. Saw molten lava, rock, steam, and smoke shooting into the air from the center of a salt lagoon that had been formed on one spur of the island.  The wind created by the disturbance could be felt for several miles.  Red-hot lava literally covered the Tahoma with volcanic sand and pumice, and the ship made for the leeward of the island, about six miles, where the temperature was uncomfortably warm.  So much lava fell on the ship it had to be hosed down. (September 1910).  The Tacoma returned several weeks later, and found a land of hot ashes and baked mud, and from the center a great column of scalding water spouted.  There was still a loud rumbling form beneath the surface and it was so loud the men, when standing only a few feet apart, had to shout at each other to be heard.  There was pitiful evidence of the terrific heat, for bird skeletons were found in great numbers lying about the island where they had been veritably roasted alive.  The heat and the fumes had been so potent that the tiny skeletons disintegrated into fine powder when an attempt was made to pick them up.\"\r\n   Powers (1916) states that there are no reports on Bogoslof for 1911 or 1912.\r\n   Newhall and Melson (1983) estimate that the volume of the Metcalf, McCullogh, and Tahoma Peak lava domes (1906-1910) was about 5x10^6 cubic meters.","StartYear":1909,"StartMonth":9,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1910,"EndMonth":9,"EndDay":19,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Bogoslof","ParentVolcano":"Bogoslof","VolcanoID":"ak29","ParentVolcanoID":"ak29"},{"ID":564,"Name":"Akutan 1909/9","Description":"   A newspaper account of a possible eruption at Akutan in 1909 is as follows:\r\n   From the Nevada State Journal, September 8, 1909: \"Captain M. Webber, of the Alaska pack steamer Lehua, which arrived [to San Francisco] today from the Aleutian Islands, reports that when his vessel left the island the volcano Akutan was in violent eruption.  Lava was issuing in great volume.\"  The article then continues to state erroneously that this is the first \"disturbance\" reported since 1887.","StartYear":1909,"StartMonth":9,"StartDay":8,"StartTime":null,"StartQualifier":2,"StartQualifierUnit":"Months","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":561,"Name":"Shishaldin 1910/8","Description":"   A newspaper account from August 15, 1910, describes an eruption of Shishaldin: \"The steamer Corwin has arrived from Nome [to Seward] with the report that Mount Shishaldin, the highest volcanic peak in the Unimak Islands, is again in eruption.  Officers of the Corwin say that when they passed the island a few days ago the volcano was more active than during the former eruption.\r\n   \"A great column of fire shot high into the air and volumes of smoke poured from the crater.  The snow which at the time of the previous eruption had not melted far from the crater has entirely disappeared from the sides of the mountain.  The Corwin was covered with volcanic ashes.\"","StartYear":1910,"StartMonth":8,"StartDay":7,"StartTime":null,"StartQualifier":14,"StartQualifierUnit":"Days","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":242,"Name":"Akutan 1911","Description":"   Finch (1935) writes that Hugh McGlashan said that the 1911 eruption of Akutan threw an \"appreciable\" amount of ash over Akutan Village.","StartYear":1911,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":444,"Name":"Wrangell 1911/4","Description":"   From Motyka (1983): \"[T]he Chitina Leader (January 28, 1911) reported that natives had observed an increase in the size of the vapor plume issuing from the summit of Mount Wrangell.  This increase followed two minor tremors on the morning of January 21, 1911.  The following headline account of an eruption from Mount Wrangell appeared in the April 15, 1911, edition of the Chitina Leader: 'Last night about 9:20 p.m. a flash which was at first mistaken for lightning, was observed at the summit of Mount Wrangell.  This was followed in a minute or so by another, which was recognized then as a tongue of flame issuing from the crater of the mountain.  In about five minutes, an immense volume of fire swept up into the sky * * * Height of the column was judged by the known height of the mountain to have been from two to three thousand feet.  This was succeeded by a couple of flashes similar to the first seen after which the giant mountain relapsed into comparative quiet, although clouds of unusually black smoke continued to pour from the main crater for some time afterwards.'\r\n   \"Reports of eruptive activity continued into mid-November, 1911.\r\n   \"The Valdez Weekly Miner (April 28, 1912) carried an account from Tonsina ' * * * large clouds of smoke and vapor pouring out of a crater and ascending high into the air.'  A prospector from Kotsina reported very strong sulphur fumes on the south-southwest flank and claimed that Mount Wrangell had 'broken out in several different places, all low down on the mountain and a considerable distance from the big crater' (Valdez Daily Prospector, September 13, 1912).  The latter may be a reference to the cluster of fumaroles that perforate the glacier ice at about 3660 m (12,000 ft) elevation on the west-southwest flank of the mountain.  Another account, appearing in the September 15, 1912, Valdez Weekly Miner claimed that 'lava was flowing down the west flank of the volcano and that great columns of smoke were rising from the mountain top.'\"","StartYear":1911,"StartMonth":4,"StartDay":28,"StartTime":null,"StartQualifier":7,"StartQualifierUnit":"Days","EndYear":1912,"EndMonth":9,"EndDay":15,"EndTime":null,"EndQualifier":2,"EndQualifierUnit":"Months","Volcano":"Wrangell","ParentVolcano":"Wrangell","VolcanoID":"ak326","ParentVolcanoID":"ak326"},{"ID":142,"Name":"Makushin 1912","Description":"   Coats (1950) reports smoke from Makushin in 1912.","StartYear":1912,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":243,"Name":"Akutan 1912","Description":"   Sapper (1917) reports that during 1912, Akutan was \"smoking or steaming\" whenever the mountain was visible.","StartYear":1912,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":359,"Name":"Shishaldin 1912","Description":"   Sapper (1917) reported smoke or steam from Shishaldin in 1912.","StartYear":1912,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":472,"Name":"Mageik 1912","Description":"   Mount Mageik experienced a large landslide during the 1912 eruption of Novarupta and Mount Katmai.  That deposit is described by Hildreth and others (2000) as follows: \"The youngest of the three [debris avalanches] was emplaced in Martin Creek on 6 June 1912 during the eruption at Novarupta, presumably triggered by the seismicity accompanying caldera collapse at Mount Katmai (Hildreth, 1991).  The deposit is overlain by most of the 1912 fallout but not by the earliest layers (Fierstein and Hildreth, 1992).  Described in detail by Griggs (1920, 1922), who called it 'the Mageik Landslide', the 1912 avalanche deposit extends 6 km southeast of its headwall and overruns the medial part of the more subdued larger deposit [see fig. 2 in original text].  Consisting predominantly of angular blocks of fresh dacite, it broke loose from a steep face glacially carved into a stack of dacite lava flows that make up the southeast planeze of the Southwest Summit edifice, leaving behind a 120-m-high scarp with a rim at the 3,000-ft level.  The deposit has millions of angular blocks larger than 1 m (mostly dacite, plus sparse basement sandstone), contains dacite slabs as long as 20 m, and supports hummocks as high as 20 m.  It locally left superelevated trimlines and ponded drainages along its abrupt margins.  About 800 m wide proximally, the deposit spreads out to 1.5 km medially and covers about 6 square km.  Griggs (1920) estimated its area as more than 10 square km, but this included parts of the subjacent older deposit.  Although thickness (5-30 m) is hard to average, the volume is probably in the range 0.05-0.1 cubic km.\"  While impressive, this landslide does not represent a volcanic eruption.\r\n   Powers (1958) erroneously (see note by Fierstein and Hildreth, 2001, below) reported an ash eruption at Mount Mageik in 1912.  \r\n   From Fierstein and Hildreth (2001): \"Not a single one of the 20th century tephra eruptions of Mageik listed in Simkin and Siebert's (1994) \"Volcanoes of the World\" seems plausible.  Configuration of the crater has not changed since it was first photographed in 1923; there are no juvenile ejecta in the crater or around its rim (except a scattering of 1912 pumice clasts from Novarupta); and the only late Holocene fall deposits on the or near the lower flanks of Mageik are the Novarupta pumice falls of 1912 and the black Trident ash of 1953.\"","StartYear":1912,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mageik","ParentVolcano":"Mageik","VolcanoID":"ak187","ParentVolcanoID":"ak187"},{"ID":456,"Name":"Novarupta 1912/6","Description":"   Fierstein and Hildreth (2001) provide information about the magitude of the 1912 eruption at Novarupta and Katmai: \"The world's largest volcanic eruption of the 20th century broke out at Novarupta [see fig. 1 in original text] in June 1912, filling with hot ash what came to be called the Valley of Ten Thousand Smokes and spreading downwind more fallout than all other historical Alaskan eruptions combined.  Although almost all the magma vented at Novarupta, most of it had been stored beneath Mount Katmai 10 km away, which collapsed during the eruption. Airborne ash from the 3-day event blanketed all of southern Alaska, and its gritty fallout was reported as far away as Dawson, Ketchikan, and Puget Sound [see fig. 21 in original text].  Volcanic dust and sulfurous aerosol were detected within days over Wisconsin and Virginia; within 2 weeks over California, Europe, and North Africa; and in latter-day ice cores recently drilled on the Greenland ice cap.\"\r\n   Schaaf (2004) contains excerpts and summaries of eyewitness accounts of the eruption; a copy of this publication is available online at \u003ca target=\"_blank\" href = \"https://www.nps.gov/articles/aps-v11-i1-c9.htm\" \u003e https://www.nps.gov/articles/aps-v11-i1-c9.htm\u003c/a\u003e.  Detailed, firsthand narratives of the events as experienced at Kodiak are given in Perry, 1914, and Erskine, 1962.\r\nHildreth and Fierstein also published a free download tome of information about this eruption: \u003ca target=\"_blank\" href =\"https://pubs.usgs.gov/pp/1791/\"\u003ehttps://pubs.usgs.gov/pp/1791/\u003c/a\u003e\r\n   From Fierstein and others (1998): \"On the afternoon of June 6, 1912, an ominous cloud rose into the sky above Mount Katmai on the Alaska Peninsula. The cloud quickly reached an altitude of 20 miles, and within 4 hours, ash from a huge volcanic eruption began to fall on the village of Kodiak, 100 miles to the southeast. By the end of the eruption on June 9th, the ash cloud, now thousands of miles across, shrouded southern Alaska and western Canada, and sulfurous ash was falling on Vancouver, British Columbia, and Seattle, Washington. The next day the cloud passed over Virginia, and by June 17th it reached Algeria in Africa.  \r\n   \"During the 3 days of the eruption, darkness and suffocating conditions caused by falling ash and sulfur dioxide gas immobilized the population of Kodiak. Sore eyes and respiratory distress were rampant, and water became undrinkable. Radio communications were totally disrupted, and with visibility near zero, ships couldn't dock. Roofs in Kodiak collapsed under the weight of more than a foot of ash, buildings were wrecked by ash avalanches that rushed down from nearby hillslopes, and other structures burned after being struck by lightning from the ash cloud. \r\n   \"Similar conditions prevailed elsewhere in southern Alaska, and several villages were abandoned forever. Animal and plant life was decimated by ash and acid rain from the eruption. Bears and other large animals were blinded by ash and starved when large numbers of the plants and small animals they lived on were wiped out. Millions of dead birds that had been blinded and coated by volcanic ash littered the ground. Aquatic organisms, such as mussels, insect larvae, and kelp, as well as the fish that fed upon them, perished in ash-choked shallow water. Alaska's salmon-fishing industry was devastated, especially from 1915 to 1919, because of the starvation and failure of many adult fish to spawn in ash-choked streams. \r\n   \"In 1916, a National Geographic Society expedition led by Robert Griggs visited Mount Katmai and found a 2-mile-wide crater where its summit had been before 1912. Nearby, the expedition discovered a newly formed lava dome they called 'Novarupta' and huge flows of volcanic ash filling what they named the 'Valley of Ten Thousand Smokes' for the numerous plumes of steam rising from the still hot ground. Griggs' descriptions of these spectacular features helped persuade President Woodrow Wilson to create Katmai National Monument (now National Park) in 1918. \r\n   \"In the 1950's, volcanologists discovered that the 1912 eruption was actually from Novarupta, not Mount Katmai. Novarupta's eruption had removed so much molten rock (magma) from beneath Mount Katmai that it caused a cubic mile of Katmai's summit to collapse.\"\r\n   Hildreth (1983) gives the following detailed description of the events of the eruption: \"Because there were no geophysical instruments in Alaska, no scientfic observers in the district, and no eyewitnesses with a view of the VTTS [Valley of Ten Thousand Smokes], most reports of seismic, acoustic, and eruptive phenomena were not necessarily very accurate, chronologically or descriptively.  The most reliable data are the visual observations from aboard the steamer Dora and the record of tephra falls at Kodiak [see figs. 1, 4, in original text] (Martin, 1913; Griggs, 1922).  Martin visited Kodiak, Uyak, Katmai village, and Cold Bay [see fig. 1 in original text]  in August of 1912 and gathered what accounts he could from residents of the district, but he did not venture inland to the volcanoes nor was he able to interview anyone from the two bands of native hunter-fishermen said to have been within 30 and 40 km, respectively, north and south of Novarupta at the time of the initial outburst.  Reconstructions of the eruptive sequence by Griggs (1922) and Fenner (1923, 1925, 1950) are heavily inferential, overinterpretive both of Martin's data and of latter-day interviews with people said to have been at Savonoski when the eruption began (see below), and suffer badly from the incorrect assumption that much of the tephra had come from Mt. Katmai.  The following is a critical reappraisal of what appear to be the facts, as assembled largely by G.C. Martin (1913; and unpublished USGS field notes); all times cited are adjusted to Alaskan local time.  \r\n   \"Earthquakes were reported to have been felt at Katmai village (30 km SSE of Novarupta) as early as the evening of 31 May, and severe shocks were felt at Uyak, Kanatak, and Nushugak (200 km WNW) on 4 and 5 June.  On the morning of 6 June, explosions were heard at Nushugak and at Seldovia (240 km ENE) but there were no reports of accompanying seismicity or ash clouds.  The same morning the Dora left Uyak at 0845 and steamed north-eastward up Shelikof Strait, the Katmai-group volcanoes in full view with a 'strong westerly breeze and fine clear weather,' but no one aboard noticed a tephra column until 1300 (when the vessel was ~88 km southeast of Novarupta).  That column was clearly Plinian and, as shown below by the stratigraphic data, it was predominantly rhyolitic; the cloud overtook the Dora by 1500 and began dropping ash at Kodiak (170 km ESE) [see figs. 1, 4, in original text] by 1700. \r\n   \"Separate interviews with two individuals said to have been in or near Savonoski (30 km N) on the morning of 6 June were conducted in 1918 (Griggs, 1922, p. 17) and in 1923 (Fenner, 1925, p. 216); these have been interpreted to suggest that the ash flow in the VTTS began in the morning several hours prior to the first high tephra column.  This is quite unlikely in view of: (1) the record of the Dora; (2) the fact that the basal tephra layer in the VTTS, the distinctively rhyolitic Layer A, does not occur atop the ash-flow deposit; and (3) the common association of pumiceous pyroclastic flows with the collapse of vertical eruption columns.  Preliminary eruptive activity at Novarupta on the morning of 6 June is quite reasonable and may be the best explanation of the noise and dust reported that morning at Savonoski and the explosions heard at Nushugak and Seldovia; but a major eruption column and a rhyolitic ash flow several km^3 in volume are certainly excluded prior to 1300.  \r\n   \"Major shocks that punctuated virtually continuous seismic activity were reported locally at ~1300 and ~2300 on 6 June and ~2240 on 7 June.  These times are not necessarily very accurate.  The first instrumentally recorded teleseism (at Seattle) is reported to have arrived at 1241 on 6 June (Fenner, 1925).  Harvard, Ottawa, and several Eurasian stations recorded many teleseisms originating in southwest Alaska between 1805 on 6 June and ~2100 on 11 June.  One of these near midnight on 6/7 June has been estimated at magnitude 6.4 and another at 0606 on 10 June at magnitude 7.0 (Coffman and von Hake, 1973).  Earthquakes following the main phases of the eruption were felt at Cold Bay (60 km SSW) on 50 of the 70 days through mid-August (Fenner, 1925).  \r\n   \"A great explosion, accompanied by an earthquake felt at Cold Bay ~1300 on 6 June (Martin, 1913), was audible throughout the region and close in time to the first recorded teleseism and to the first sighting of tephra by the Dora.  Another blast at ~1500 on 6 June, for which no accompanying earthquake was noted, may have been the most severe outburst of all, being heard for hundreds of kilometers (Martin, 1913).  Martin suggested, but did not cite any evidence for, explosions synchronous with the large earthquakes felt nearby at ~2300 on 6 June and 2240 on 7 June.  There were, however, reports of loud noises between midnight and 0200 on 8 June, at Katanak (95 km SW) and at Cordova (590 km ENE) (Martin, 1913; Fenner, 1925).  Explosions continued to be heard, some as far away as Juneau (1200 km) until 10 June, though how many of the noises may have been thunder is impossible to assess.  \r\n   \"Major tephra eruptions, first noted by the Dora at 1300 on 6 June, continued to fall heavily on downwind settlements nearby until 9 June.  The principal sector of dispersal was southeastward [see fig. 1 in original text], and the most distant positive record of ashfall was in Puget Sound (2400 km SE); atmospheric effects were worldwide (Griggs, 1922; Volz, 1975).  In the main downwind direction at Kodiak (170 km ESE) there were three discrete periods of ashfall [see fig. 4 in original text]: (1) 1700 6 June until 0910 7 June; (2) ~1200 7 June until 1430 8 June; and (3) during the night of 8/9 June.  The 9th of June dawned clear, and no further ash-falls were recorded on Kodiak Island.  A major vapor plume and, possibly, sporadic ashfalls close to the source lasted all summer (Martin, 1913; Griggs, 1922; Fenner, 1925).  Timing of the emplacement of the Novarupta dome is poorly known; its extrusion followed the last major tephra fall and was complete at the time of discovery on 31 July 1916. \r\n   \"Details of correlation between audible explosions, tephra falls, and seismic events are not well known.  Martin (1913) is the principal source, but his article has been misread and overinterpreted and ensuing errors propagated in successive publications.  The seismicity does not correlate very well with eruptive events, and indeed there need be no correspondence (e.g. Filson and others, 1973; Nairn and others, 1976; Yokoyama and others, 1981).  Much of the seismic activity seems more likely to have been related to fitful subsidence of Katmai and Novarupta calderas.  \r\n   \"At the onset of eruption, no one is known to have had a view of the VTTS (much less the Novarupta area itself), and only the party of native fishermen then southwest of Katmai village en route to Cold Bay may have been in a position to see Mt. Katmai.  The Savonoski interviews (above) smack of ex post facto embellishment, although Martin (1913, p. 147) accepted a third hand report in 1912 that the villagers there may have seen Mt. Katmai after its collapse, but before 9 June.  It is not clear where they might have had such a view, because, even notwithstanding the ash clouds, Mt. Katmai is not visible from Savonoski or along their escape route down the lake to Naknek [see fig. 1 in original text]. Martin, Griggs, and Fenner accepted such reports to mean that Mt. Katmai had lost its top by the afternoon of 6 June.  This may be true, but it is not clear how Mt. Katmai could have been seen at all during the eruptive interval at Novarupta or what meaning should be attached to such expressions as 'blown off' or 'blown up.'  No definitive geologic evidence has been found to fix the timing of Mt. Katmai's collapse, but it may be a reasonable inference that in addition to the syneruptive earthquakes, much of the summer-long seismicity can be attributed to such collapse, as well as to tectonic adjustments over a somewhat wider area, or even to dome emplacement at Novarupta.\"\r\n   Hildreth (1983) also reports that \"pumice in the intial fall unit (A) is 100% rhyolite, but fall units atop the ash flow are \u003e98% datcite; black andesitic scoria is common only in the ash flows and in near-vent air-fall tephra.\"  He also states: The Novarupta lava dome is \"diameter 380 m, its hieight ~65 m, and the intermediate (mostly dacite) lava interbanded with the rhyolite consitutes no more than 5% of the exposure; most of the conspicuous banding reflects textural variation in the rhyolite.\"\r\n   Fierstein and Hildreth (2001) estimate that the Novarupta eruption of 1912 ejected \"at least 17 cubic km of fall deposits and about 11 cubic km of ash-flow tuff (ignimbrite) * * * emplaced in about 60 hours, representing a magma volume of about 13 cubic km (Fierstein and Hildreth, 1992).  Hildreth (1987) estimates the volume of the Novarupta lava dome to be 0.005 cubic km.","StartYear":1912,"StartMonth":6,"StartDay":6,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1912,"EndMonth":6,"EndDay":9,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Novarupta","ParentVolcano":"Novarupta","VolcanoID":"ak203","ParentVolcanoID":"ak203"},{"ID":494,"Name":"Katmai 1912/6","Description":"   Fierstein and Hildreth (2001) provide information about the magitude of the 1912 eruption at Novarupta and Katmai: \"The world's largest volcanic eruption of the 20th century broke out at Novarupta [see fig. 1 in original text] in June 1912, filling with hot ash what came to be called the Valley of Ten Thousand Smokes and spreading downwind more fallout than all other historical Alaskan eruptions combined.  Although almost all the magma vented at Novarupta, most of it had been stored beneath Mount Katmai 10 km away, which collapsed during the eruption. Airborne ash from the 3-day event blanketed all of southern Alaska, and its gritty fallout was reported as far away as Dawson, Ketchikan, and Puget Sound [see fig. 21 in original text].  Volcanic dust and sulfurous aerosol were detected within days over Wisconsin and Virginia; within 2 weeks over California, Europe, and North Africa; and in latter-day ice cores recently drilled on the Greenland ice cap.\"\r\n   Schaaf (2004) contains excerpts and summaries of eyewitness accounts of the eruption; a copy of this publication is available online at \u003ca target=\"_blank\" href = \"https://www.nps.gov/articles/aps-v11-i1-c9.htm\" \u003e https://www.nps.gov/articles/aps-v11-i1-c9.htm\u003c/a\u003e.  Detailed, firsthand narratives of the events as experienced at Kodiak are given in Perry, 1914, and Erskine, 1962.\r\nHildreth and Fierstein also published a free download tome of information about this eruption: \u003ca target=\"_blank\" href =\"https://pubs.usgs.gov/pp/1791/\"\u003ehttps://pubs.usgs.gov/pp/1791/\u003c/a\u003e\r\n   From Fierstein and others (1998): \"On the afternoon of June 6, 1912, an ominous cloud rose into the sky above Mount Katmai on the Alaska Peninsula. The cloud quickly reached an altitude of 20 miles, and within 4 hours, ash from a huge volcanic eruption began to fall on the village of Kodiak, 100 miles to the southeast. By the end of the eruption on June 9th, the ash cloud, now thousands of miles across, shrouded southern Alaska and western Canada, and sulfurous ash was falling on Vancouver, British Columbia, and Seattle, Washington. The next day the cloud passed over Virginia, and by June 17th it reached Algeria in Africa.  \r\n   \"During the 3 days of the eruption, darkness and suffocating conditions caused by falling ash and sulfur dioxide gas immobilized the population of Kodiak. Sore eyes and respiratory distress were rampant, and water became undrinkable. Radio communications were totally disrupted, and with visibility near zero, ships couldn't dock. Roofs in Kodiak collapsed under the weight of more than a foot of ash, buildings were wrecked by ash avalanches that rushed down from nearby hillslopes, and other structures burned after being struck by lightning from the ash cloud. \r\n   \"Similar conditions prevailed elsewhere in southern Alaska, and several villages were abandoned forever. Animal and plant life was decimated by ash and acid rain from the eruption. Bears and other large animals were blinded by ash and starved when large numbers of the plants and small animals they lived on were wiped out. Millions of dead birds that had been blinded and coated by volcanic ash littered the ground. Aquatic organisms, such as mussels, insect larvae, and kelp, as well as the fish that fed upon them, perished in ash-choked shallow water. Alaska's salmon-fishing industry was devastated, especially from 1915 to 1919, because of the starvation and failure of many adult fish to spawn in ash-choked streams. \r\n   \"In 1916, a National Geographic Society expedition led by Robert Griggs visited Mount Katmai and found a 2-mile-wide crater where its summit had been before 1912. Nearby, the expedition discovered a newly formed lava dome they called 'Novarupta' and huge flows of volcanic ash filling what they named the 'Valley of Ten Thousand Smokes' for the numerous plumes of steam rising from the still hot ground. Griggs' descriptions of these spectacular features helped persuade President Woodrow Wilson to create Katmai National Monument (now National Park) in 1918. \r\n   \"In the 1950's, volcanologists discovered that the 1912 eruption was actually from Novarupta, not Mount Katmai. Novarupta's eruption had removed so much molten rock (magma) from beneath Mount Katmai that it caused a cubic mile of Katmai's summit to collapse.\"\r\n   Hildreth (1983) gives the following detailed description of the events of the eruption: \"Because there were no geophysical instruments in Alaska, no scientfic observers in the district, and no eyewitnesses with a view of the VTTS [Valley of Ten Thousand Smokes], most reports of seismic, acoustic, and eruptive phenomena were not necessarily very accurate, chronologically or descriptively.  The most reliable data are the visual observations from aboard the steamer Dora and the record of tephra falls at Kodiak [see figs. 1, 4, in original text] (Martin, 1913; Griggs, 1922).  Martin visited Kodiak, Uyak, Katmai village, and Cold Bay [see fig. 1 in original text]  in August of 1912 and gathered what accounts he could from residents of the district, but he did not venture inland to the volcanoes nor was he able to interview anyone from the two bands of native hunter-fishermen said to have been within 30 and 40 km, respectively, north and south of Novarupta at the time of the initial outburst.  Reconstructions of the eruptive sequence by Griggs (1922) and Fenner (1923, 1925, 1950) are heavily inferential, overinterpretive both of Martin's data and of latter-day interviews with people said to have been at Savonoski when the eruption began (see below), and suffer badly from the incorrect assumption that much of the tephra had come from Mt. Katmai.  The following is a critical reappraisal of what appear to be the facts, as assembled largely by G.C. Martin (1913; and unpublished USGS field notes); all times cited are adjusted to Alaskan local time.  \r\n   \"Earthquakes were reported to have been felt at Katmai village (30 km SSE of Novarupta) as early as the evening of 31 May, and severe shocks were felt at Uyak, Kanatak, and Nushugak (200 km WNW) on 4 and 5 June.  On the morning of 6 June, explosions were heard at Nushugak and at Seldovia (240 km ENE) but there were no reports of accompanying seismicity or ash clouds.  The same morning the Dora left Uyak at 0845 and steamed north-eastward up Shelikof Strait, the Katmai-group volcanoes in full view with a 'strong westerly breeze and fine clear weather,' but no one aboard noticed a tephra column until 1300 (when the vessel was ~88 km southeast of Novarupta).  That column was clearly Plinian and, as shown below by the stratigraphic data, it was predominantly rhyolitic; the cloud overtook the Dora by 1500 and began dropping ash at Kodiak (170 km ESE) [see figs. 1, 4, in original text] by 1700. \r\n   \"Separate interviews with two individuals said to have been in or near Savonoski (30 km N) on the morning of 6 June were conducted in 1918 (Griggs, 1922, p. 17) and in 1923 (Fenner, 1925, p. 216); these have been interpreted to suggest that the ash flow in the VTTS began in the morning several hours prior to the first high tephra column.  This is quite unlikely in view of: (1) the record of the Dora; (2) the fact that the basal tephra layer in the VTTS, the distinctively rhyolitic Layer A, does not occur atop the ash-flow deposit; and (3) the common association of pumiceous pyroclastic flows with the collapse of vertical eruption columns.  Preliminary eruptive activity at Novarupta on the morning of 6 June is quite reasonable and may be the best explanation of the noise and dust reported that morning at Savonoski and the explosions heard at Nushugak and Seldovia; but a major eruption column and a rhyolitic ash flow several km^3 in volume are certainly excluded prior to 1300.  \r\n   \"Major shocks that punctuated virtually continuous seismic activity were reported locally at ~1300 and ~2300 on 6 June and ~2240 on 7 June.  These times are not necessarily very accurate.  The first instrumentally recorded teleseism (at Seattle) is reported to have arrived at 1241 on 6 June (Fenner, 1925).  Harvard, Ottawa, and several Eurasian stations recorded many teleseisms originating in southwest Alaska between 1805 on 6 June and ~2100 on 11 June.  One of these near midnight on 6/7 June has been estimated at magnitude 6.4 and another at 0606 on 10 June at magnitude 7.0 (Coffman and von Hake, 1973).  Earthquakes following the main phases of the eruption were felt at Cold Bay (60 km SSW) on 50 of the 70 days through mid-August (Fenner, 1925).  \r\n   \"A great explosion, accompanied by an earthquake felt at Cold Bay ~1300 on 6 June (Martin, 1913), was audible throughout the region and close in time to the first recorded teleseism and to the first sighting of tephra by the Dora.  Another blast at ~1500 on 6 June, for which no accompanying earthquake was noted, may have been the most severe outburst of all, being heard for hundreds of kilometers (Martin, 1913).  Martin suggested, but did not cite any evidence for, explosions synchronous with the large earthquakes felt nearby at ~2300 on 6 June and 2240 on 7 June.  There were, however, reports of loud noises between midnight and 0200 on 8 June, at Katanak (95 km SW) and at Cordova (590 km ENE) (Martin, 1913; Fenner, 1925).  Explosions continued to be heard, some as far away as Juneau (1200 km) until 10 June, though how many of the noises may have been thunder is impossible to assess.  \r\n   \"Major tephra eruptions, first noted by the Dora at 1300 on 6 June, continued to fall heavily on downwind settlements nearby until 9 June.  The principal sector of dispersal was southeastward [see fig. 1 in original text], and the most distant positive record of ashfall was in Puget Sound (2400 km SE); atmospheric effects were worldwide (Griggs, 1922; Volz, 1975).  In the main downwind direction at Kodiak (170 km ESE) there were three discrete periods of ashfall [see fig. 4 in original text]: (1) 1700 6 June until 0910 7 June; (2) ~1200 7 June until 1430 8 June; and (3) during the night of 8/9 June.  The 9th of June dawned clear, and no further ash-falls were recorded on Kodiak Island.  A major vapor plume and, possibly, sporadic ashfalls close to the source lasted all summer (Martin, 1913; Griggs, 1922; Fenner, 1925).  Timing of the emplacement of the Novarupta dome is poorly known; its extrusion followed the last major tephra fall and was complete at the time of discovery on 31 July 1916. \r\n   \"Details of correlation between audible explosions, tephra falls, and seismic events are not well known.  Martin (1913) is the principal source, but his article has been misread and overinterpreted and ensuing errors propagated in successive publications.  The seismicity does not correlate very well with eruptive events, and indeed there need be no correspondence (e.g. Filson and others, 1973; Nairn and others, 1976; Yokoyama and others, 1981).  Much of the seismic activity seems more likely to have been related to fitful subsidence of Katmai and Novarupta calderas.  \r\n   \"At the onset of eruption, no one is known to have had a view of the VTTS (much less the Novarupta area itself), and only the party of native fishermen then southwest of Katmai village en route to Cold Bay may have been in a position to see Mt. Katmai.  The Savonoski interviews (above) smack of ex post facto embellishment, although Martin (1913, p. 147) accepted a third hand report in 1912 that the villagers there may have seen Mt. Katmai after its collapse, but before 9 June.  It is not clear where they might have had such a view, because, even notwithstanding the ash clouds, Mt. Katmai is not visible from Savonoski or along their escape route down the lake to Naknek [see fig. 1 in original text]. Martin, Griggs, and Fenner accepted such reports to mean that Mt. Katmai had lost its top by the afternoon of 6 June.  This may be true, but it is not clear how Mt. Katmai could have been seen at all during the eruptive interval at Novarupta or what meaning should be attached to such expressions as 'blown off' or 'blown up.'  No definitive geologic evidence has been found to fix the timing of Mt. Katmai's collapse, but it may be a reasonable inference that in addition to the syneruptive earthquakes, much of the summer-long seismicity can be attributed to such collapse, as well as to tectonic adjustments over a somewhat wider area, or even to dome emplacement at Novarupta.\"\r\n   Hildreth (1983) also reports that \"pumice in the intial fall unit (A) is 100% rhyolite, but fall units atop the ash flow are \u003e98% datcite; black andesitic scoria is common only in the ash flows and in near-vent air-fall tephra.\"  He also states: The Novarupta lava dome is \"diameter 380 m, its hieight ~65 m, and the intermediate (mostly dacite) lava interbanded with the rhyolite consitutes no more than 5% of the exposure; most of the conspicuous banding reflects textural variation in the rhyolite.\"\r\n   Fierstein and Hildreth (2001) estimate that the Novarupta eruption of 1912 ejected \"at least 17 cubic km of fall deposits and about 11 cubic km of ash-flow tuff (ignimbrite) * * * emplaced in about 60 hours, representing a magma volume of about 13 cubic km (Fierstein and Hildreth, 1992).  Hildreth (1987) estimates the volume of the Novarupta lava dome to be 0.005 cubic km.","StartYear":1912,"StartMonth":6,"StartDay":6,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1912,"EndMonth":6,"EndDay":9,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Katmai","ParentVolcano":"Katmai","VolcanoID":"ak147","ParentVolcanoID":"ak147"},{"ID":462,"Name":"Martin 1913","Description":"   From Miller and others (1998): \"Mount Martin, venting a prominent steam plume, was first photographed in 1913 but erroneously called Mt. Katmai (Griggs, 1922).  In 1915, Griggs (1922) recognized that the mountain was an unknown, fumarolically active volcano west of Mount Mageik and named it in honor of George C. Martin, who was the first to visit and describe the Katmai area following the 1912 eruption.\r\n   \"Numerous reports of activity from Mount Martin are contained in the literature.  Sapper (1927) reported strong 'smoke' clouds from Mount Martin during the period 1913-1919; Griggs (1922) who explored the area during that time, mentioned only steam.\"  The persistent and conspicuous steam plume present at Mt. Martin does not constitute a volcanic eruption.","StartYear":1913,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1919,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Martin","ParentVolcano":"Martin","VolcanoID":"ak189","ParentVolcanoID":"ak189"},{"ID":562,"Name":"Shishaldin 1913/6","Description":"   Although initial accounts from the steamship Dora report a volcanic eruption of Shishaldin, with vivid descriptions, the June 11 edition of the Fairbanks Daily Times published a retraction of the accounts, saying \"The reports of volcanic activity, which were sent from here [Seward] several days ago and which circulated generally throughout the States, were of a character more sensational than the actual conditions warranted.\r\n   \"It is true that reports of activity were received here from the westward, but the activity was mostly in the form of vapor and smoke.  No ashes were seen by those who brought the story to Seward.\"\r\n   The initial accounts of the event included such vivid descriptions as this one, from the June 8, 1913 edition of the Fairbanks Daily Times: \"All volcanoes to the westward of this place [Seward] are in active eruption, according to reports brought by the steamship Dora, which arrived here today.  The volcanic stretch in the Aleutians is particularly active.\r\n   \"On Unimak Island, Mount Shishaldin, one of the largest volcanoes in the eastern Aleutians, is active and is throwing ashes and flame high into the air.  Practically all of the volcanoes of the Aleutian chain are spouting ashes.\"","StartYear":1913,"StartMonth":6,"StartDay":5,"StartTime":null,"StartQualifier":14,"StartQualifierUnit":"Days","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":119,"Name":"Bogoslof 1913/7","Description":"   Powers (1916) gives the following information on this eruption: \"[I]n July, 1913, a brief statement refers to the crater [of Tahoma Peak] as being plainly visible with steam and smoke slowly issuing from it.  Activity apparently ceased during this year, for the commanding officer of the steamer Patterson, which passed Bogoslof on its way to pick up survivors of the Tahoma [The Tahoma struck a reef on the 20th of September, 1914], reports that 'the Bogoslof Islands showed three peaks in 1914, none of which was smoking.'\"  \r\n   Jaggar (1930) relates similar information: \"In July, 1913, this crater had steam and smoke slowly issuing from it, but the following year all smoking had ceased.  During the next eight years Tahoma Peak, as the new hill of 1910 was called, was eroded away, and a channel was again opened between Castle Rock and Grewingk so that a boat could sail between the two older islands.  Grewingk had greatly diminished in size, and Castle Rock was now two rocky horns with a big accumulation of sand and gravel heaps piled against them, especially on the northern and eastern sides, these trailing off into a long sand spit at the north, and the whole of this larger island was surrounded by sand beaches.\"","StartYear":1913,"StartMonth":7,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Bogoslof","ParentVolcano":"Bogoslof","VolcanoID":"ak29","ParentVolcanoID":"ak29"},{"ID":486,"Name":"Trident 1913/9","Description":"   During the years 1913 to 1919 (the years of the National Geographic Society expeditions to the Katmai National Monument), Trident Volcano was often observed to be \"smoking\" or \"steaming.\"  Eicher and Rounsefell (1957) report a \"lighter\" eruption in the Katmai area in September, 1913.  This eruption may have occurred at Trident.\r\n      However, Hildreth (1983) disbelieves this account: \"Published compilations notwithstanding, there are no credible reports of historic eruptions in the Katmai group except at Novarupta in 1912 and at Trident in 1953 - 1968.\"","StartYear":1913,"StartMonth":9,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Trident","ParentVolcano":"Trident","VolcanoID":"ak288","ParentVolcanoID":"ak288"},{"ID":33,"Name":"Tanaga 1914","Description":"   Coats (1950): a lava flow was observed at Tanaga in 1914.","StartYear":1914,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Tanaga","ParentVolcano":"Tanaga","VolcanoID":"ak280","ParentVolcanoID":"ak280"},{"ID":495,"Name":"Katmai 1914","Description":"   Coleman (1946) reports that \"There were eruptions of Katmai on a smaller scale in 1914, but the volcano is now quiet.\"  However, Hildreth (1983) states: \"Published compilations notwithstanding, there are no credible reports of historic eruptions in the Katmai group except at Novarupta in 1912 and at Trident in 1953 - 1968.\"","StartYear":1914,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Katmai","ParentVolcano":"Katmai","VolcanoID":"ak147","ParentVolcanoID":"ak147"},{"ID":560,"Name":"Shishaldin 1914/7","Description":"   An Associated Press article of July 10, 1914, gives an account of an eruption at Shishaldin: \"Further details of the tremendous volcanic activity in progress along the Alaskan peninsula west of Seward, and reaching to the Aleutian Islands, were given today by Captain McMullen of the steamer Dirigo, which brought first news of the outburst.\r\n   \"Observations made by the crew of the Dirigo July 1 showed that a new crater had opened on the north side of Mount Shishaldin, the most westerly of the three peaks reported in eruption.  Flowing lava had cut a wide path in the snow for miles down the side of the mountain.  A strong westerly wind blew a heavy cloud of smoke from the mountain.\"","StartYear":1914,"StartMonth":7,"StartDay":1,"StartTime":null,"StartQualifier":1,"StartQualifierUnit":"Months","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":200,"Name":"Pavlof 1914/7","Description":"   This eruption was recorded in the log book of the US Coast and Geodetic Survey Patterson's log book. On July 6, 1914, the log book records: 'At 12:18 a distant rumbling, which some on deck took for thunder was heard. It came from a direction between W and WNW (mag) and lasted longer than thunder and sounded like a landslide with many distinct explosions and a minute later two separate explosions were heard, though faintly. At 12:30 more rumbling was heard although at this time it sounded more like thunder and seemed to be from a source higher above the horizon. At 12:30 the fog suddenly disappeared - it was flat calm and a dark blue black cloud was seen to the westward. Notified the Commanding Officers that there was probably a volcanic explosion and by this time some solid particles in the atmosphere could be felt by the eyes and soon it began to collect on the deck. A light SW-SSW breeze now sprang up and the cloud spread to the northward. Peals of thunder were heard - though not very loud - at intervals about 10 mins and at 1:30 some lighning was noticed. The cloud now spread to the southward and at 1:30 it was so dark that it was necessary to start the dyanamo. The decks were covered by 2 o'clock with a fine black dust and it was very difficult to look into the wind as it bothered the eyes so much. At 2:30 it began to brighten to the northward and soon became normal - mist to the northward with the black cloud passing over Unga and Popof Islands. At 2:05 dropped the dory - Dr. Edson left ship to answer call of SS Windber. Dory returned with the captain of the Windber. Ship lay to. 3:05 Dory returned with Dr. Edson - hoisted dory and at 3:15 squared on course ENE with the \"Windber\" following. 5:40 Overtook the cloud hanging over Popof and another light shower of volcanic ash was experienced at 5:30. Light SW breezes.\"  Images of these log book pages are visible at the following URLs: http://oldweather.s3.amazonaws.com/ow3/final/USCS%20Patterson/Book%2016/IMG_6579_0.jpg and http://oldweather.s3.amazonaws.com/ow3/final/USCS%20Patterson/Book%2016/IMG_6579_1.jpg . Ther e are also transcripts from the Old Weather project: http://forum.oldweather.org/index.php?topic=384.msg74647#msg74647 .\r\n   Sapper (1917) writes that on July 5 or 6 [1914], during the night or at 6 am, there was the beginning of an eruption.  There were light explosions from 12:18 to 3 pm, and loud detonations could be heard at Corvin [Unga] Island (10 to 30 minutes apart.  \"Stronger ashfalls.\" \r\n   The eruption was still evident when the steamer Dirigo passed by Pavlof on July 10, 1914: \"Pavlof volcano, on the Alaska peninsula, west of the Shumagin island 100 miles off Mount Shishaldin, was also active when the Dirigo passed.  The action of Pavlof was peculiar, the mountain throwing out a black ash, a light fall of which was noticed on the Dirigo\" (Associated Press, 1914).\r\n   On Friday, October 16, 1914, the US Coast and Geodetic Survey's Patterson vessel again noted eruptive activity from Pavlof: \"Pavlof volcano was seen in active eruption - dense volumes of smoke and flame reaching several thousand feet above the crater were seen. No noise could be heard and only a very slight trace of ashes could be detected.\" (see log book images here: http://oldweather.s3.amazonaws.com/ow3/final/USCS%20Patterson/Book%2017/IMG_6692_1.jpg and http://oldweather.s3.amazonaws.com/ow3/final/USCS%20Patterson/Book%2017/IMG_6692_0.jpg )\r\n   The United States Commissioner at Unga gave T.A. Jaggar black sand that fell at Unga from Pavlof during a July 6, 1914 eruption (Kennedy and Waldron, 1955). Coats (1955) start date of July 15, 1914 is certainly too late for the beginning of the eruption.","StartYear":1914,"StartMonth":7,"StartDay":6,"StartTime":null,"StartQualifier":1,"StartQualifierUnit":"Days","EndYear":1914,"EndMonth":10,"EndDay":16,"EndTime":null,"EndQualifier":3,"EndQualifierUnit":"Months","Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":473,"Name":"Mageik 1915","Description":"   Griggs (1922) reported a \"thin column of steam\" from Mount Mageik in 1915.\r\n   Fierstein and Hildreth (2001) discount this account as an eruption: \"Not a single one of the 20th century tephra eruptions of Mageik listed in Simkin and Siebert's (1994) \"Volcanoes of the World\" seems plausible.  Configuration of the crater has not changed since it was first photographed in 1923; there are no juvenile ejecta in the crater or around its rim (except a scattering of 1912 pumice clasts from Novarupta); and the only late Holocene fall deposits on the or near the lower flanks of Mageik are the Novarupta pumice falls of 1912 and the black Trident ash of 1953.\"","StartYear":1915,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mageik","ParentVolcano":"Mageik","VolcanoID":"ak187","ParentVolcanoID":"ak187"},{"ID":751,"Name":"Pavlof 1915/8","Description":"From the US Coast and Geodetic Survey Patterson's logbooks, on August 26, 1915, from notes made at 11:33 am: \"Overcast to cloudy and fair. Gentle to mod. NW breezes with frequent stiff and fresh squalls. During last hour breeze shifted to ENE and fell light. Slight and mod swells to smooth. Pavlof Vol belched several columns of black smoke and some steam. One distinct explosion was heard (10-12).\"","StartYear":1915,"StartMonth":8,"StartDay":26,"StartTime":"11:00:00","StartQualifier":1,"StartQualifierUnit":"Hours","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":513,"Name":"Gilbert 1917/8","Description":"   Maddren (1919), who visited Akun and Unalaska Islands during August and September 1917, describes the sulfur deposits of Akun Island, near Mt. Gilbert.  He reports: \"The sulfatara is in rather mild or semidormant activity.  Within the smaller area of about 5 acres small volumes of steam and scalding water, accompanied by a small quantity of hydrogen sulphide gas (H2S), issue from fissures at widely spaced intervals, and the remainder of the area shows no particular evidences of the escape of subterranean heat.  The most striking evidence of solfatarism is of chemical decomposition of the rock.\"","StartYear":1917,"StartMonth":8,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Gilbert","ParentVolcano":"Gilbert","VolcanoID":"ak108","ParentVolcanoID":"ak108"},{"ID":201,"Name":"Pavlof 1917/10","Description":"   Jaggar (1929) reports that an eruption occurred at Pavlof in October, 1917, and was followed by \"dust falls\" and a severe earthquake at King Cove.","StartYear":1917,"StartMonth":10,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":496,"Name":"Katmai 1920/3","Description":"   Coats (1950) reports minor eruptions at Katmai on March 9, 1920.  However, Hildreth (1983) states: \"Published compilations notwithstanding, there are no credible reports of historic eruptions in the Katmai group except at Novarupta in 1912 and at Trident in 1953 - 1968.\"","StartYear":1920,"StartMonth":3,"StartDay":9,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Katmai","ParentVolcano":"Katmai","VolcanoID":"ak147","ParentVolcanoID":"ak147"},{"ID":445,"Name":"Wrangell 1921/7","Description":"   From Motyka (1983): \"Local inhabitants reported a small eruption on July 3, 1921.  The plume was seen from Chitina, located southeast of volcano, towering well above Mount Wrangell with the source somewhere on the north flank of the mountain (fig. 7 [a photograph of the event]).  This plume was also observed by Wm. Cameron from near Sourdough, which is located northwest of the volcano.\"","StartYear":1921,"StartMonth":7,"StartDay":3,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1921,"EndMonth":7,"EndDay":3,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Wrangell","ParentVolcano":"Wrangell","VolcanoID":"ak326","ParentVolcanoID":"ak326"},{"ID":497,"Name":"Katmai 1921/11","Description":"   Coats (1950) reports minor explosive eruptions at Katmai on November 27, 1921.  However, Hildreth (1983) states: \"Published compilations notwithstanding, there are no credible reports of historic eruptions in the Katmai group except at Novarupta in 1912 and at Trident in 1953 - 1968.\"","StartYear":1921,"StartMonth":11,"StartDay":27,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Katmai","ParentVolcano":"Katmai","VolcanoID":"ak147","ParentVolcanoID":"ak147"},{"ID":23,"Name":"Gareloi 1922","Description":"   Coats (1950) reports a major explosive eruption at Gareloi in 1922.","StartYear":1922,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Gareloi","ParentVolcano":"Gareloi","VolcanoID":"ak106","ParentVolcanoID":"ak106"},{"ID":463,"Name":"Martin 1922","Description":"   From Hubbard (1931): \"The day [in 1922] was unusually clear, and Martin, Mageik, and Kukak volcanoes were sending graceful columns of smoke high in the air, the ship's sextant giving the height of Martin's plume as close to 20,000 feet.\"  This activity does not constitute a volcanic eruption.","StartYear":1922,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Martin","ParentVolcano":"Martin","VolcanoID":"ak189","ParentVolcanoID":"ak189"},{"ID":475,"Name":"Mageik 1922","Description":"   From Hubbard (1931): \"The day [in 1922] was unusually clear, and Martin, Mageik, and Kukak volcanoes were sending graceful columns of smoke high into the air.\"  This activity does not constitute a volcanic eruption.","StartYear":1922,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mageik","ParentVolcano":"Mageik","VolcanoID":"ak187","ParentVolcanoID":"ak187"},{"ID":360,"Name":"Shishaldin 1922/10","Description":"   From Finch (1934):  In autumn of 1922, the Daly brothers of False Pass reported \"glowing material for down the north slope and mud flows bearing blocks of ice in Clinker Creek\" at Shishaldin Volcano.\r\n   An Associated Press article from June 26, 1923, gives additional description of the November 20, 1922 eruption: \"The 1922 eruption of Shishaldin was picturesque, according to eyewitnesses.  Great flames burst from the crater and the top of the volcano was blown high into the air, about two hundred feet of the summit disappearing.  Lava poured down the canyons, melting the snow, and the black streams could be seen for miles.  Lava continued to flow for three days, and heavy smoke was observed for more than a week.  At one of the light houses on Unimak Pass, the flames lighted up the sky for days, appearing to, according to the keepers, in the form of a cross.\"\r\n   Juergen Kienle's unpublished notes on file at the University of Alaska Fairbanks contain a notation about this eruption, stating that Shishaldin between December 1922 and Jan 1923 was \"in eruption\" and deposited considerable ash.\r\n   The June 23, 1923 Associated Press article also describes Shishaldin as \"emitting heavy bursts of smoke in May [1923]\" according to the crew of the Coast Guard Cutter Haida.","StartYear":1922,"StartMonth":10,"StartDay":null,"StartTime":null,"StartQualifier":2,"StartQualifierUnit":"Months","EndYear":1923,"EndMonth":1,"EndDay":null,"EndTime":null,"EndQualifier":5,"EndQualifierUnit":"Months","Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":202,"Name":"Pavlof 1922/12","Description":"   Kennedy and Waldron (1955) write \"'flames' reached a height of 2,000 feet above the volcano that lighted the village of Belkofsky the evening of December 24, 1922, and 'flames' were again reported in the winter of 1923.\"\r\n   An Associated Press article from July 23, 1923, describes some of the 1922 Pavlof eruption: \"On Christmas eve, 1922, Pavlof volcano, on the Alaskan Peninsula, was in eruption and lava flows for several days thereafter, with a heavy emission of smoke for a longer period.\"\r\n   Jaggar (1929) also reports flames during the winter of 1923. At least two newspapers published accounts of an eruption on January 7, 1923, saying that the top of the mountain had blown off (Nenana News, 1923; Fairbanks Daily News Miner, 1923).  The News Miner article further states \"It is believed that the explosion was caused by the earthquake of December 30 in this district.\"","StartYear":1922,"StartMonth":12,"StartDay":24,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1923,"EndMonth":2,"EndDay":null,"EndTime":null,"EndQualifier":2,"EndQualifierUnit":"Months","Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":458,"Name":"Griggs 1923","Description":"   In 1923, Smith (1925) reported Mt. Griggs had active fumaroles, constantly sending \"columns of white fumes many hundred feet in the air.\"  This activity does not constitute a volcanic eruption.","StartYear":1923,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Griggs","ParentVolcano":"Griggs","VolcanoID":"ak112","ParentVolcanoID":"ak112"},{"ID":474,"Name":"Mageik 1923","Description":"   Fenner (1930) reported a constant heavy roar and steam at Mount Mageik in 1923, stating that \"rocks and ash on rim of crater suggest recent eruption.\"\r\n   Fierstein and Hildreth (2001) discount this account as an eruption: \"Not a single one of the 20th century tephra eruptions of Mageik listed in Simkin and Siebert's (1994) \"Volcanoes of the World\" seems plausible.  Configuration of the crater has not changed since it was first photographed in 1923; there are no juvenile ejecta in the crater or around its rim (except a scattering of 1912 pumice clasts from Novarupta); and the only late Holocene fall deposits on the or near the lower flanks of Mageik are the Novarupta pumice falls of 1912 and the black Trident ash of 1953.\"","StartYear":1923,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mageik","ParentVolcano":"Mageik","VolcanoID":"ak187","ParentVolcanoID":"ak187"},{"ID":203,"Name":"Pavlof 1924/1","Description":"   Kennedy and Waldron (1955) report a \"strong ash explosion followed by steam and ash eruptions occurred on January 17, 1924.\" \r\n   It is likely that the actual date of the start of the eruption was January 6, as a news article from the Fairbanks Daily News Miner explains (February 6, 1924): \"Writing from Belkofsky under date of January 16, a correspondent for the Seward Gateway tells of Mount Pavlof recent eruption as follows:\r\n   \"'On January 6, Mt. Pavlof, which has been smoking for some months again erupted accompanied by * * * earthquake shocks and pitch darkness, the shocks lasting for several minutes and accompanied by a violent electrical display.  The natives were very much frightened and started to pack their things preparatory to leaving the village, but they were finally calmed down by Rev. Bordukovsky who went from house to house assuring them the danger would soon be over.  Since the eruption the volcano is throwing out a huge column of smoke and steam, and residents of the village believe that is is only a matter of time until the top blows off the mountain, as was the case at Mt. Katmai.  It is hard to understand the terror of living under an active volcano, by people who do not see these things; the black darkness, and the violent explosions, the falling of rocks and lava, the lurid flashes of lava thrown high in the air, all produce a feeling of helplessness and terror that must be experienced to be believed.\"\r\nThe Modesto Evening News, May 27, 1924, states that the eruption had ceased.","StartYear":1924,"StartMonth":1,"StartDay":6,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1924,"EndMonth":5,"EndDay":null,"EndTime":null,"EndQualifier":4,"EndQualifierUnit":"Months","Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":361,"Name":"Shishaldin 1925","Description":"   Coats (1950) reported Shishaldin \"active; type of activity unknown\" in 1925.\r\n   An Associated Press article published in the November 14, 1925 edition of the Fairbanks Daily News Miner attributes a warm Alaskan winter to \"the eruption of Mount Shishaldin\" but gives no details about eruption date or description.","StartYear":1925,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":120,"Name":"Bogoslof 1926/7","Description":" Miller and others (1998) summarizes this eruption: \"Renewed submarine explosions between the two islands [Castle Rock and Fire Island] in 1926 produced another conical dome by early 1927.  A tephra ring, located about 3 m above high tide, surrounded the new dome and connected it to Fire Island and Castle Rock, thus forming a single elongate island.  By July, 1927, the circular dome was 60 m high and 300 m across and was circled by a shallow lagoon of warm water.\"\r\n   Jaggar (1930) records the start of this eruption as follows: \"The new activity had started in July of 1926 when there was open water between the two older rocks [Castle Rock and Fire Island].  An explosive eruption was then seen by a whaler, and the natives reported explosions July 17 as seen from nearby islands.  The water was greatly muddied and the whaler on August 12 saw black smoke with darkness accompanied by thunder and lightning, ending with a cloud of white steam and 'fire' about 2 p.m.  There was also an explosion in December, 1926, and it is probable that the lava dome of 1927 emerged thereafter.  Probably the eruption began with a series of lava pulsations, alternating with explosion.\"\r\n   Jaggar visited the Bogoslof Islands in June, 1927 (Jaggar, 1930), and reports the following: \"The writer visited Bogoslof for the second time July 6, 1927, and found a new period of moderate lava activity inaugurated, with a pile of steaming lava rising from a warm lagoon in the midst of sand banks, and again these banks joined all of Bogoslof into one island with a complete ring-shaped salt water lagoon, surrounded in turn by a complete ring of sand permitting no connection with the sea except by seepage.  The lagoon was at 70 degrees F., there were the usual herds of sea lions and myriads of birds, the bottom sand and pebbles of the lagoon were all coated with orange colored ochre, the lagoon was everywhere only two or three feet deep, there were numerous skeletons of dead birds on the beach, and in the sand were impact craters made by newly fallen bombs having rough aa surfaces.  There were blocks of pumice one to two feet in diameter.  The central lava heap was about 200 feet high and 1,000 feet wide.  Its crest consisted of uniform aa clinker, steaming much more heavily than in this picture of a year later.  It made no noise, and it is characteristic of Bogoslof that during most of the visits reported noise has been absent.\"\r\n   Jaggar (1930) ends with \"A landing party on Bogoslof July 27, 1929 reported all quiet.\"\r\n   Newhall and Melson (1983) estimate the total volume of the lava dome produced during this event to be about 1x10^6 cubic meters.","StartYear":1926,"StartMonth":7,"StartDay":17,"StartTime":null,"StartQualifier":10,"StartQualifierUnit":"Days","EndYear":1928,"EndMonth":6,"EndDay":null,"EndTime":null,"EndQualifier":6,"EndQualifierUnit":"Months","Volcano":"Bogoslof","ParentVolcano":"Bogoslof","VolcanoID":"ak29","ParentVolcanoID":"ak29"},{"ID":144,"Name":"Makushin 1926/12","Description":"  Jaggar (1927): \"A dispatch from Dutch Harbor of December 31, 1926, states that Mount Makushin, on Unalaska in the Aleutian Islands, erupted the evening of December 30 with 'fountains of fire and masses of vapor,' making a spectacular display.  A slight earthquake accompanied the eruption and there was fear for the safety of Makushin village.\"","StartYear":1926,"StartMonth":12,"StartDay":30,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":2,"Name":"Kiska 1927","Description":"   Jaggar (1927) reports that Kiska is a \"fuming volcano.\"  \r\n   Miller and others (1998) summarizes from Coats (1961):  \"Coats briefly visited Kiska volcano in 1947 and found no evidence of recent ash flows nor any active fumaroles; the youngest lava flows were more heavily vegetated at any given altitude than counterparts on adjacent islands known to have been erupted in the 20th century.  The youngest lava flows before 1962 were probably between 100 and several hundred years old.  Coats concluded that any events between 1905 and 1947 were at most solfataric.\"","StartYear":1927,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kiska","ParentVolcano":"Kiska","VolcanoID":"ak161","ParentVolcanoID":"ak161"},{"ID":24,"Name":"Gareloi 1927","Description":"   Jaggar (1927) writes that Gareloi is \"always fuming.\" and Jaggar (1928) writes that he visited Gareloi and Bogoslof volcanoes and that Gareloi was \"sending up dense yellow fumes from its summit crater-cup.\"","StartYear":1927,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Gareloi","ParentVolcano":"Gareloi","VolcanoID":"ak106","ParentVolcanoID":"ak106"},{"ID":85,"Name":"Seguam 1927","Description":"   Coats (1950) reported smoke from Seguam during 1927.","StartYear":1927,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Seguam","ParentVolcano":"Seguam","VolcanoID":"ak246","ParentVolcanoID":"ak246"},{"ID":244,"Name":"Akutan 1927","Description":"   From Jaggar (1945): Akutan was \"smoking and flaming more in 1928 than 1927.\"  Finch (1935) also reported slight earthquakes with rumbles in 1927.  Newspaper accounts are more detailed.\r\n   From the Warren Tribune, June 6, 1928: \"The largest volcanic mountain on Akutan Island was believed to be in eruption today.  The motorship Patterson, some distance away, reported to Dutch Harbor that dense clouds of black smoke could be seen rolling from the island.\"\r\n   From the Fairbanks Daily News Miner, June 7, 1928: \"Captain Pederson of the motorship Patterson reported that clouds of black smoke and fire are bursting from a new place on the mountain of Akutan on Unalga Pass, while the old vent on the peak, which heretofore has been continually smoking, is quiet.\"\r\n   From the Evening State Journal, July 17, 1928: \"Heavy volcanic eruptions on Akutan Island, one of the Aleutian chain, were reported here today by the U.S. coast guard cutter Unalga.\r\n   \"The inhabitants of native villages on the island are being terrorized by earthquake shocks, the Unalga reported.\r\n   \"Steam and lava were seen coming from the crater of the volcano on the island, officers of the boat said.\"","StartYear":1927,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1928,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":498,"Name":"Katmai 1927","Description":"   From Jaggar (1927): \"When Dr. Jaggar was at Naknek May 24, 1927, the teacher there, who had been to the Valley of Ten Thousand Smokes, reported that a trapper in January, 1927, had seen an ash eruption from one of the Katmai hills, and that two trappers were missing who had gone into that region.\"   However, Hildreth (1983) states: \"Published compilations notwithstanding, there are no credible reports of historic eruptions in the Katmai group except at Novarupta in 1912 and at Trident in 1953 - 1968.\"","StartYear":1927,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Katmai","ParentVolcano":"Katmai","VolcanoID":"ak147","ParentVolcanoID":"ak147"},{"ID":464,"Name":"Martin 1927/5","Description":"   From Jaggar (1927): \"Mageik and Martin were two volcanoes seen by Dr. Jaggar to be steaming, looking northwest from Shelikof Strait on May 18, 1927.\"  This steaming does not constitute a volcanic eruption.","StartYear":1927,"StartMonth":5,"StartDay":18,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Martin","ParentVolcano":"Martin","VolcanoID":"ak189","ParentVolcanoID":"ak189"},{"ID":476,"Name":"Mageik 1927/8","Description":"   Jaggar (1927) reports on an event in 1927: \"The Seattle 'News-Tribune' carries an Associated Press dispatch of the date September 30 stating that Mageik Volcano of the Katmai group erupted explosively 'late in August (1927.)'  The authority quoted is Captain Harry W. Crosby, President of the Crosby Fisheries, who spent the summer aboard his schooner-cannery 'Salmon King' in the northeast arm of Uganik Bay on the northwest side of Kodiak Island.  Mageik and Martin were two volcanoes seen by Dr. Jaggar to be steaming, looking northwest from Shelikof Strait on May 18, 1927.  Both took part in the great Katmai eruptions of 1912.  Mageik is forty nautical miles from the middle of Shelikof Strait, and sixty miles from the Crosby anchorage in Uganik Bay.  NEW PARA \"Thousands of tons of pumice stone and ashes were reported by Crosby as showered over an area 50 miles square. The article quotes him:\r\n   \"'We were about 50 miles off the Alaskan Peninsula in clear weather, when suddenly we noticed a gigantic puff at the top of Mageik.  Soon the air was filled with volcano ash, and it began to rain pumice stone.  After the explosion, the volcano smoked like a factory chimney.  A short distance from the ship we found large quantities of pumice stone, some pieces as big as your fist, floating on the ocean.\r\n   \"'We scooped up a bushel or more of the stones and brought them to Seattle.  For five days the eruption continued, and the mountain was still smoking when we left for Seattle. \r\n   \"'Each morning while we were off the Alaskan Peninsula, the decks and rigging of the ship would be covered with the fine powdered volcanic ash, some of it so white that it resembled snow.  The first duty of the crew in the mornings would be to sweep the decks clear and to dust off the rigging.\r\n   \"'The eruption followed a period of unusual weather, a great calm with scarcely a breath of air, and a depressing atmosphere.  The air was full of white volcanic ash for a week, and thousands of tons of pumice stone fell around us.' \r\n   \"No dates or ship's positions appear in this article, but apparently the vessel did not sail until five days after the major explosion.  Captain Crosby is a reliable commercial man, navigator, and fisherman of many years' experience in Alaskan waters.\"\r\n   Fierstein and Hildreth (2001) provide clarification that this account does not describe a volcanic eruption at Mount Mageik: \"Although fumarolic 'puffs' are common, there is no evidence of a post-1912 plinian pumice-fall deposit anywhere between Mount Mageik and Shelikof Strait.  The [Jaggar] report also mentioned fine white ash falling on the decks, but fine white ash still falls occasionally today during spells of dry summer weather when windstorms loft ash from the barren surface of the Valley of Ten Thousand Smokes to altitudes of many kilometers.\"\r\n   Fierstein and Hildreth (2001) also firmly state: \"Not a single one of the 20th century tephra eruptions of Mageik listed in Simkin and Siebert's (1994) \"Volcanoes of the World\" seems plausible.  Configuration of the crater has not changed since it was first photographed in 1923; there are no juvenile ejecta in the crater or around its rim (except a scattering of 1912 pumice clasts from Novarupta); and the only late Holocene fall deposits on the or near the lower flanks of Mageik are the Novarupta pumice falls of 1912 and the black Trident ash of 1953.\"\r\n   Hildreth (1983) also states: \"In particular, a pumice shower said by a fisherman to have issued from Mt. Mageik in August 1927 (Jaggar, 1927) cannot be corroborated by detectable deposits in the volcano's crater or on its flanks.\"","StartYear":1927,"StartMonth":8,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mageik","ParentVolcano":"Mageik","VolcanoID":"ak187","ParentVolcanoID":"ak187"},{"ID":362,"Name":"Shishaldin 1927/11","Description":"   Jaggar (1928): \"A notice of December 8 [1927] states that two volcanoes on Unimak had been smoking for ten days, after a season of unusual activity in the Aleutians.  The smoke and vapor is stated to be 'in comparatively small quantities.'\"  One of these volcanoes is probably Shishaldin.","StartYear":1927,"StartMonth":11,"StartDay":28,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1927,"EndMonth":12,"EndDay":8,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":363,"Name":"Shishaldin 1928/5","Description":"   An Associated Press article of May 16, 1928 states that Shishaldin was erupting on May 15, 1928: \"* * * Captain L.W. Perkins, commanding officer of the coast guard cutter Unalga reported that Shishaldin, volcano on Unimak Island, was in a state of eruption.\r\n   \"The message, which was sent from Dutch Harbor, Alaska, read: 'At one o'clock on the morning of the 15th, the coast guard cutter Unalaga Shishaldin on Unimak Island.  At that time the volcano was showing unusual activity, emitting heavy smoke and frequent bursts of flame.'\"\r\n   From Jaggar (1929): \"In 1928 Shishaldin was smoking heavily in August.\"","StartYear":1928,"StartMonth":5,"StartDay":15,"StartTime":null,"StartQualifier":14,"StartQualifierUnit":"Days","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":102,"Name":"Yunaska 1929","Description":"   Powers (1958) reports smoke from Yunaska in 1929.","StartYear":1929,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Yunaska","ParentVolcano":"Yunaska","VolcanoID":"ak329","ParentVolcanoID":"ak329"},{"ID":204,"Name":"Pavlof 1929","Description":"      From Kennedy and Waldron (1955): \"Crew members of the steamer Starr reported that Pavlof was unusually active in December, 1929. * * * Rev. D. Hotovitsky (Hawaiian Volcano Observatory, 1931) reported that Pavlof was smoking all of the summer of 1931.  The volcano was in active eruption about May 20, 1931, and at times a glow was seen at the crater; the ash fall was noticeable.\" \r\n   Two Associated Press articles in the Fairbanks Daily News Miner (March 30 and 31) give a few details about a March 29-March 31 eruptive episode.  From the March 31 article: \"Pavloff volcano is quiet, said a short wave radio message picked up by C.W. Watson, amateur operator.  The message was signed by Lilly Osterback, amateur at Unga.\r\n   \"'The volcano is now quiet after throwing out great clouds of smoke and flame,' said the message.  'The eruption started at 8 p.m. March 29 and lasted until 6 a.m. today.  Lookers estimated smoke and flame were thrown 2,000 feet above the top of the mountain.  The southeast face of Pavloff for a space of 12 miles is now black from peak to the water.  The crater is filled with hot lava.'\"\r\n   From Finch (1931): in 1931, Pavlof was \"smoking nearly all summer\" and  \"in active eruption about May 20 1931, making a noticeable ashfall, and at times flow was discernible at the crater.\"","StartYear":1929,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1931,"EndMonth":9,"EndDay":null,"EndTime":null,"EndQualifier":2,"EndQualifierUnit":"Months","Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":465,"Name":"Martin 1929","Description":"   Jaggar (1929) reported that Martin and Mageik volcanoes were steaming throughout 1929.  This activity does not constitute a volcanic eruption.","StartYear":1929,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1929,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Martin","ParentVolcano":"Martin","VolcanoID":"ak189","ParentVolcanoID":"ak189"},{"ID":477,"Name":"Mageik 1929","Description":"   Jaggar (1929) states that Martin and Mageik were steaming throughout 1929.  Miller and others (1998) write that a report of an eruption at Mageik in December, 1929, was possibly based on a newspaper account of \"unusual activity\" and from reports of a ship's crew - \"the crew probably was no closer than 25 km to the volcano.\"  The Fairbanks Daily News of December 7, 1929 states that passengers of the steamer Starr viewed \"great white smoke clouds\" \"belching forth\" from Mount Mageik, and that the smoke was \"plainly visible from the decks of the Starr, which was 20 miles at sea.\"  \r\n      Fierstein and Hildreth (2001) also state: \"Not a single one of the 20th century tephra eruptions of Mageik listed in Simkin and Siebert's (1994) \"Volcanoes of the World\" seems plausible.  Configuration of the crater has not changed since it was first photographed in 1923; there are no juvenile ejecta in the crater or around its rim (except a scattering of 1912 pumice clasts from Novarupta); and the only late Holocene fall deposits on the or near the lower flanks of Mageik are the Novarupta pumice falls of 1912 and the black Trident ash of 1953.\"","StartYear":1929,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mageik","ParentVolcano":"Mageik","VolcanoID":"ak187","ParentVolcanoID":"ak187"},{"ID":180,"Name":"Chiginagak 1929/3","Description":"   Jaggar (1932): \"A mountain to the west of Kanatak was reported fuming in March 1929, and this description might apply to Chiginagak.\"\r\n   However, Miller and others (1998) report that the 1929 eruption of Chiginagak was \"based on a brief newspaper account of \"unusual activity\" at Chiginagak and 6 other volcanoes observed by the crew of a ship which probably passed no closer than 25 km.\"  The December 14, 1929 Associated Press article does not provide further information on Chiginagak, except to say that it is \"also on the mainland near Katmai.\"\r\n   Simkin and Siebert (1994) report the eruption as a questionable eruption in December, 1929.","StartYear":1929,"StartMonth":3,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Chiginagak","ParentVolcano":"Chiginagak","VolcanoID":"ak49","ParentVolcanoID":"ak49"},{"ID":25,"Name":"Gareloi 1929/4","Description":"   Coombs and others (2008) provide information about the 1929 eruption as follows: \"The 1929 eruption is the largest historical eruption of Gareloi and also unique in its eruptive style and composition. The most detailed description of the eruption is given by oats (1959) who summarized the first-hand observations of William H. Dirks, Sr. (Coats, 1959; p. 2): 'In April of 1929, there was an eruption. A terrible quake * * * split the mountain from its crater right to the beach. Ashes fell, completely covering their cabins and boats* * * '\r\n   \"Coats further elaborated on the series of events from observations of the deposits, which were 17 years old when he visited the island and still unmodified either by vegetation or further eruptive activity. According to Coats, the eruption excavated 13 explosion craters, ranging in diameter from 80 to 1,600 m, along a 4.3-km-long, south-southeast trending fissure [see figs. 5 and 7 in original text]. On the basis of work by Coats (1959) and our fieldwork, the eruption began with formation of the current South Peak crater and a possible directed blast to the south. Following this, an explosive eruption covered the southern half of the island in several meters of tephra fall [see fig. 8 in original text]. At this time, the upper craters were excavated. Small pyroclastic flow deposits are interbedded with tephra-fall deposits, indicating that pyroclastic flows accompanied tephra fall. \r\n   \"During the second half of the eruption, the composition of the juvenile clasts in the fall deposits became more mafic; craters formed lower on the flank, and small lava flows effused from them. Sometime after explosive activity ceased, debris flows from the summit carried hydrothermally altered blocks down the volcano's southern slope.\r\n   \"The eruption's total volume is unknown, as much of the ejecta were deposited offshore. Onland pyroclastic deposits represent about 16,000 cubic m, and that of lava is about 2,500 cubic m.\"\r\n\r\n   Miller and others (1998), also summarize Coats (1956): \"In April of 1929, a phreatic eruption opened an elongate crater 1600 m in maximum diameter just below the southern summit; further explosions produced 12 smaller craters aligned along a south- to southeast-trending fissure.  Glassy pumice, lapilli, scoria, and accidental rocks were then ejected from the lower craters, blanketing an area roughly 2.5 by 5 km on the southeast slope.  Ash layers up to 2 m thick on Ogliuga Island, located about 16 km southeast, may be attributable at least in part to this eruption (Coats, 1956, p. 92) and several centimeters of pyroclastic debris are known to have fallen on Atka Island (about 300 km eastward) during the event.  Extrusion of lava, which formed short steep flows, occurred at four sites along the fissure after the tephra eruptions.  Various metallic oxides and halides (including atacamite, paratacamite and hematite) were deposited in several of the lower craters.  Activity may have continued into 1930.\r\n   \"Juvenile material erupted in 1929 may be significantly more siliceous than the older basaltic or basaltic andesite rocks.  The lava was apparently highly viscous and generally formed blocky, vesicular, or scoriaceous flows, one of which is 75 m wide and 15 m thick.  Orthopyroxene, brown hornblende, plagioclase (average composition about An48), and clinopyroxene were observed in lava flows and pyroclastics of the 1929 eruption (Coats, 1959, p. 254-255).\"\r\n\r\nFinch (1931): \"Gareloi volcano, a peak 5,334 feet high far to the west in the Aleutian Islands, was very active during the spring and summer of 1930.  The appearance of half of the island was said to be changed by lava flows from fissures, and a hut was destroyed belonging to fox farmers.\"\r\n\r\nJaggar (1932): \"Gareloi in the western Aleutians was said to erupt so violently in 1930 as to change its appearance by lava flows from fissures.\"","StartYear":1929,"StartMonth":4,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1930,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Gareloi","ParentVolcano":"Gareloi","VolcanoID":"ak106","ParentVolcanoID":"ak106"},{"ID":364,"Name":"Shishaldin 1929/5","Description":"   From Jaggar (1929): \"Shishaldin, the great volcano on Unimak Island, was 'flaming high' on May 28, 1929, and glowing matter was overwelling the edge of the crater and rolling down the slopes.  On June 17 Shishaldin was quiet though steam was visible when the crater was inspected with field glasses.  It was fiery again June 23 and appeared to have opened three new craters low on the north side.  On August 4 the summit steam was barely visible to the naked eye.\"","StartYear":1929,"StartMonth":5,"StartDay":28,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1929,"EndMonth":6,"EndDay":23,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":245,"Name":"Akutan 1929/6","Description":"   A June 1, 1929 Associated Press article provides the first news of this eruption: \"Intermittenly lighting the sky with flames and darkening it with ashes a new volcano today was pouring molten lava down the sides of an unnamed mountain and threatning to cover all of Akutan Island, residents of the upper Aleutian Islands reported here.\r\n   \"The island, 1,000 miles southwest of Cordova, normally would have about a dozen residents at this time of year. * * * Heavy ash from the volcano was gradually covering neighboring islands, observers reported, and blanketing vegetation with a coat of grey.  Volcanic ash has been seen here [Cordova, AK] but whether this was from the Akutan eruption or from some unreported disturbance in turbulent islands of the Bering Sea was unknown.\"\r\n   From Jaggar (1929): Akutan's \"lower slopes were covered with ash June 18, 1929.\"  July 1929, he reported it was fuming again.\r\n   An Associated Press article published in the June 25, 1929, edition of the Fairbanks Daily News Miner reported \"Passengers arriving here [Seattle] yesterday morning on the steamer W.M. Tupper from Bethel said that a volcano in the Aleutian Islands just west of Unimak Pass is active.  It is casting a dull red glow in the sky.\"\r\n   From Finch (1935): The December, 1929 eruption was witnessed by Axel Swenson, watchman at the whaling station.  \"A branch of a flow poured through the northwest gap in the crater rim, but it reached only a short distance down the flank of the mountain.   During the summer of 1929 puffs of smoke or ash-laden steam frequently arose from the crater, and these puffs were usually followed by a crackling roar.  In December 1929 a glow was observed over the crater for several days.\"\r\n   Byers and Barth (1953) report puffs of smoke in 1929, and a glow seen over crater for several days during December, with lava flow through crater gap.  \"The December, 1929, lava flow rests on an older ash-covered flow, which is grouped with the 1929 lava * * * as pre-1947 lava.  A mud flow, which moved down through the crater gorge, originated at the front of the December, 1929, lava flow, with which it is gradational.  This mud flow extends down to the valley bottom, north and north-west of the volcano, and there rests on older interbedded mud flows and ash deposits.\"","StartYear":1929,"StartMonth":6,"StartDay":1,"StartTime":null,"StartQualifier":2,"StartQualifierUnit":"Days","EndYear":1929,"EndMonth":12,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":287,"Name":"Cleveland 1929/7","Description":"   Jaggar (1929) reports: \"Mount Cleveland and a volcano to the west of it, in the region of the Islands of the Four Mountains, were smoking heavily in July.\" * * * \"The above note on the fuming of Mount Cleveland recalls the heavy earthquake just south of those islands at the edge of the Aleutian deep reported in the Volcano Letter No. 220.  This occurred March 6, 1929.\"","StartYear":1929,"StartMonth":7,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":105,"Name":"Kagamil 1929/12","Description":"   Coats (1950) reports Kagamil active in December, 1929.","StartYear":1929,"StartMonth":12,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kagamil","ParentVolcano":"Kagamil","VolcanoID":"ak142","ParentVolcanoID":"ak142"},{"ID":499,"Name":"Katmai 1929/12","Description":"   Jaggar (1932) reported that \"volcanoes of the Katmai group continued fuming\" in 1929, and Coats (1950) reported Katmai active in December, 1929.  However, Hildreth (1983) states: \"Published compilations notwithstanding, there are no credible reports of historic eruptions in the Katmai group except at Novarupta in 1912 and at Trident in 1953 - 1968.\"","StartYear":1929,"StartMonth":12,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Katmai","ParentVolcano":"Katmai","VolcanoID":"ak147","ParentVolcanoID":"ak147"},{"ID":446,"Name":"Wrangell 1930/3","Description":"   Activity at Mount Blackburn was reported in an Associated Press article published March 26, 1930, but this activity is probably attributable to Mount Wrangell rather than Mount Blackburn.  From the article: \"Mount Blackburn is erupting again.  Chitina residents report that the eruption is spectacular, not to mention huge columns of black smoke.\"\r\n   From Motyka (1983): \"Another short eruption is reported to have occurred on April 6, 1930.  Again documented by photographs from Chitina, billowy white plumes were observed rising high above the West Crater [see figure 8 in original text for photograph of plume].","StartYear":1930,"StartMonth":3,"StartDay":26,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1930,"EndMonth":4,"EndDay":6,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Wrangell","ParentVolcano":"Wrangell","VolcanoID":"ak326","ParentVolcanoID":"ak326"},{"ID":309,"Name":"Veniaminof 1930/6","Description":"   In June, 1930, Father Hubbard (1931) witnessed ash explosions from the western intracaldera cone of Mount Veniaminof.  He climbed Mount Veniaminof and recorded: \"Here and there, at the base of the 2,000-foot cliffs on which we stood, the ice yawned away in impressive chasms, where the heat of the mountain melted the encroaching glacier.  Strangest of all was the cone in the center, packed in ice and smoking on two sides of its upbuilt rim from slag heaps of lava, and now and then coughing out black ashes over the surrounding white snows.\"","StartYear":1930,"StartMonth":6,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Veniaminof","ParentVolcano":"Veniaminof","VolcanoID":"ak301","ParentVolcanoID":"ak301"},{"ID":166,"Name":"Okmok 1931/3","Description":"   From Grey (2003): \"Jaggar (1931) relates the journal entry of Mrs. Esther Wendhab, who tended seismographs in Dutch Harbor, on March 23, 1931: 'Captain Nelson of the Eunice reported a volcano smoking terribly with thick black fumes, where before he had only observed white steam, at Tulik on Umnak Island.  He passed it March 21 and so unusual was its action he believes it is about to erupt.  There was no record on the seismograph.'\r\n   \"This eruption is reported to have continued at least until May 13 (Jaggar, 1932; Coats, 1950), when 'smoke' was still observed.  Because activity is recorded as lasting nearly two months, this may have been a time of development of the pre-1943 Cone A lava field.  Byers (1959) noted that the pre-1943 lavas to the northeast of Cone A were nearly identical in appearance to the 1945 lavas and would have been nearly indistinguishable had the 1945 eruption not been so well observed.  Also, Freiday (1945) reported that parts of what he called the 'WAVE SPAR WAC' flow (the Cone A lava field, see figure 4.4 in original text) were melted out of the snow when he flew over the caldera [see also figure 5.2 in original text].  The date of his visit is not specified, but probably during the winte rof 1942-1943 and again in early summer 1943.  Hantke (1951) calls for simultaneous eruptive activity at Okmok and Tulik in 1931, but the deeply glaciated state of Tulik precludes it having been active in historic time (Coats, 1950; Miller and others, 1998).\"","StartYear":1931,"StartMonth":3,"StartDay":21,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1931,"EndMonth":5,"EndDay":13,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Okmok","ParentVolcano":"Okmok","VolcanoID":"ak206","ParentVolcanoID":"ak206"},{"ID":246,"Name":"Akutan 1931/5","Description":"   Finch (1935) reports that on August 11, 1931: \"One vent in the cone emitted dark smoke or ash along with a rumble.\"  He also reports that smoke was observed in May 1931.\r\n   Jaggar (1931) reports that on August 11, 1931 a rumbling was heard,  and on July 24, 1931, an ascent of Akutan showed the crater was hot, with steam.","StartYear":1931,"StartMonth":5,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1931,"EndMonth":8,"EndDay":11,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":293,"Name":"Aniakchak 1931/5","Description":"   From Neal and others (2001): \"In the last 200 years, Aniakchak volcano is known to have erupted once - during about six weeks in May - June 1931. Documentation of the event is limited; the following summary is derived principally from the writings of University of Santa Clara missionary and explorer Hubbard (1931; Jan 2 and 16, 1932), who visited Aniakchak in 1930 and 1931.\r\n     The 1931 eruption was violent, included both explosive and effusive phases, and sent ash at least 600 km north of the volcano. The first sign of activity was noted about 10 a.m. on May 1, 1931, when residents of the former Meshik (now part of Port Heiden) saw a vigorous, white column of steam ascending above the crater. By noon, residents reported ground shaking, rumbling noises, and the beginning of tephra fall from a large, black mushroom cloud, intermittently illuminated by lightning, over the caldera. Cloud height was estimated to be more than 6 km above sea level. Fallout in Meshik in the early stages of eruption included ash and pea- to egg-sized, frothy, black pumice that pelted homes. Radio communications with Chignik and other communities in southwestern Alaska were hampered repeatedly by static caused by ash in the atmosphere (Anchorage Daily Times, 1931; Fairbanks Daily News-Miner, May 4, 1931). Ash fall was noted at Kanakanak (near Dillingham), 225 km north of the volcano [see fig. 2 in original text] (Fairbanks Daily News-Miner, May 2, 1931). Observers describe a constant level of eruption until May 11, when an extremely violent explosion rocked the volcano. Heavy ash fall produced total darkness for several hours near the volcano. As much as several millimeters of black ash accumulated at Chignik, and greater amounts were recorded at Ugashik [see fig. 2 in original text]. Rafts of pumice containing individual fragments as much as 20 cm across reportedly were floating in Bristol Bay west of Meshik. A 10-km-wide swath of black ash and 'almost complete darkness' observed from a boat in Bristol Bay attest to the severity of the fallout (Seward Daily Gateway, May 28, 1931). \r\n     After May 11, the eruption apparently diminished in intensity until May 20, when explosions were heard at Ugashik (75 km northeast) and at an unspecified location more than 300 km away. Beginning on May 26, intermittent small ash plumes were reported over the caldera and Chignik residents reported 'rumbling' like distant surf in the direction of Aniakchak. Several earthquakes, some described as 'severe,' were felt in Chignik and Hook Bay in late May.\r\n     Father Hubbard flew over the volcano on June 10, while the eruption was still in progress. His party first hiked to the caldera on June 13 and discovered moving, blocky lava flows at the bottom of two new explosion pits [see figs. 6A, B in original text]. A third small lava flow issued from a knob slightly above the base of the west caldera wall [see fig. 6C in original text]. Steam explosions had reamed a shallow pit in coarse ash and lapilli that blanketed a lava-flow field inside Half Cone [see fig. 6D in original text]. Although accumulation of fallout was heaviest in the western and northwestern parts of the caldera, nearly all vegetation inside the caldera was destroyed or buried. Three small lakes in the western part of the caldera (Knappen, 1929) were filled completely with ash and lapilli, and Surprise Lake was cloudy with suspended ash. Hubbard also reported dead birds, presumably killed by carbon dioxide that had accumulated in low areas near the vent. The north rim of Vent Mountain's summit crater reportedly was steaming (Regan, 1987).\"\r\n   \"* * * Earthquakes during the 1931 eruption were strong enough to be felt in Chignik, 65 km away, and to destabilize the precipitous caldera walls. Hubbard (Jan. 2. 1932) reported avalanches in progress inside Aniakchak in mid-June. The rock-avalanche lobes that extend from the south wall inside the caldera [see fig. 5 in original text] may have formed in 1931.\r\n   \"Beyond the caldera rim, fallout from the 1931 eruption affected several hundred thousand square kilometers of southwestern Alaska. As much as 1 to 2 cm of ash may have fallen in Chignik (Fairbanks Daily News-Miner, May 14, 1931). Ash reportedly was about 6 mm thick on Kodiak Island (presumably in the village of Kodiak), in Katmai National Monument2, and on the Nushagak Peninsula, and a fine dusting was reported at Holy Cross, 600 km north of the volcano. Light ash fall was reported also at Squaw Harbor on Unga Island, 140 km southwest of Aniakchak. Reindeer and caribou losses from fallout were reported to be 'heavy' at Nushagak, and dead swans and geese, believed to have died from ash ingestion, were noted at Ugashik (Hubbard, Jan. 2, 1932). From these scattered reports, we constructed a map showing the area most likely to have received noticeable amounts of ash fall [see fig. 7 in original text].\r\n   \"The volume of material erupted in 1931 is difficult to determine by traditional field methods because of the widespread dispersal of fine ash, much of it over water. In many places, because strong winds and rain have stripped the 1931 deposit completely, original thickness on land is difficult to measure accurately.  Furthermore, eyewitness accounts are few and, from our experience, prone to exaggeration. Using limited field measurements and interpretation of written accounts of ash fall during and after the eruption, we estimate the total bulk volume of the 1931 deposits to be about 0.3 to 0.5 cubic km.\r\n   \"The interaction of erupting magma and abundant water in part explains why the 1931 eruption was explosive. The conclusion that the eruption was hydrovolcanic was based on the presence of accretionary lapilli, as much as several centimeters in diameter (Hubbard, Jan. 2, 1932); rhythmic surge-and-fall deposits, exposed in the walls of the main vent; blocky lithic ejecta; and widely dispersed fine-grained ash. Also, Knappen (1929) noted standing water in the western part of the caldera prior to the eruption. That this shallow ground-water system persists is indicated by the presence of Surprise Lake and by the abundance of springs on the floor in the eastern part of the caldera.  Future eruptions may include a similar strong hydrovolcanic component as hot rising magma mixes explosively with water.\"\r\nBacon and others (2014) estimate the total volume of erupted products at about 0.9 cubic km, less than 1 percent of which was lava.","StartYear":1931,"StartMonth":5,"StartDay":1,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1931,"EndMonth":6,"EndDay":13,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":500,"Name":"Katmai 1931/5","Description":"   Finch (1931) recorded: \"Katmai volcano was observed to be smoking early in July.\"  Coats (1950) also reports Katmai smoking on May 8, 1931.  However, Hildreth (1983) states: \"Published compilations notwithstanding, there are no credible reports of historic eruptions in the Katmai group except at Novarupta in 1912 and at Trident in 1953 - 1968.\"","StartYear":1931,"StartMonth":5,"StartDay":8,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1931,"EndMonth":7,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Katmai","ParentVolcano":"Katmai","VolcanoID":"ak147","ParentVolcanoID":"ak147"},{"ID":121,"Name":"Bogoslof 1931/10","Description":"   Jaggar (1932) reports: \"\"Captain Nelson saw fire issuing from Bogoslof October 31, 1931, and found quantities of pumice near Umnak Island south of it.  This observer believed Bogoslof to be continually smoking, according to his experience, but the 'fire' was unusual.\"\r\n   In 1934, further mention is made of Bogoslof.  Hunnicutt (1943) reports that \"In 1934 Bogosloff was visited by a scientific party form the Coast Guard vessel Chelan.  When the men went on shore they feared the island would explode beneath their feet, but the scientist with them explained that the only live part of the island, volcanically speaking, was one peak named McCullock Peak which smoked continually at that time, and beyond this peak, on the opposite shore of the island, was a fissure visible at low tide.  When the tide came in, steam and gas would rise out of this crevice and bubble and steam on the surface of the sea.\"","StartYear":1931,"StartMonth":10,"StartDay":31,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Bogoslof","ParentVolcano":"Bogoslof","VolcanoID":"ak29","ParentVolcanoID":"ak29"},{"ID":288,"Name":"Cleveland 1932/1","Description":"   From Jaggar (1932): \"Captain Nelson of the 'Eunice' brought word on January 18, 1932, that Mount Cleveland on Chuginadak Island, a peak 8156 feet high, approximately 150 English miles west of Dutch Harbor, had again broken into eruption, starting about January 1, 1932.  It was reported to him that seven great puffs had occurred in one hour, the volcano sending up very dense smoke.  Generally only a little steam had been seen at the crater during previous visits.  He passes those Islands of the Four Mountains three or four times a year in his trading trips for the Alaska Commercial Company.  He was surprised to see such dense volumes of black fume when he passed the island in early January, the sky being continuously darkened.\"","StartYear":1932,"StartMonth":1,"StartDay":1,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":365,"Name":"Shishaldin 1932/2","Description":"   An Associated Press article of February 5, 1932, reported: \"Shishaldin is reported in the most violent and spectacular eruption for many years, with huge quantities of lava pouring down its uninhabited slopes and smoke and ash scattered over the Bering sea by a strong wind.\r\n   \"'The volcano presented a beautiful display of fireworks after dark, day before yesterday [February 3],' a radio message sent out by Joseph Nasenius\".\r\n   From Jaggar (1932): \"On February 10, 1932, a radio from John Gardner in False Pass informed me that Shishaldin erupted February 1, 1932, the outbreak lasting for several days with glowing material flowing down the mountain.  A newspaper dispatch of February 4 called this eruption 'the most violent and spectacular seen in the past century' for this volcano.  The report from Squaw Harbor described 'streams of lava flowing down the sides,' but this glowing material is quite as likely to be trains of red-hot bowlders [sic] for these Aleutian cones.  A strong wind carried the ashes many miles northward over the Bering Sea.  A dispatch of February 16 said that Shishaldin had again renewed its activity with boomings coming form the crater [sic] at two-minute intervals, the volcano hurling hot rocks thousands of feet into the air.\"  An Associated Press article published on the same day stated that the eruption could be heard from a distance of 50 miles.\r\n   From Finch (1932): \"While passing to the south of Shishaldin during the night of May 5-6, 1932, the writer observed a brilliant glow over the summit and for a short distance down the north-west slope.\r\n   \"There were light falls of basaltic pumice from time to time after the outbreak of February 1, 1932, until, at least, the latter part of May.  Shishaldin was grey most of the time during the spring of 1932.  The white of each new snowfall was usually darkened within a day or two by a film of ash.\"\r\n   Finch (1932) continues: \"The pressure within the volcano was never great enough during 1932 to produce a major explosion.  Fragments of pumice a little larger than a walnut were picked up at a distance of 25 miles to the north-east.  Their distribution to this distance was caused by a strong south-west wind.  Most of the material ejected quietly overwelled the crater edge and rolled down the north slope.  As a large part of this material was red hot, it continued to glow for a considerable distance below the summit.  It was noticed that the summit vent would shift slightly in position and at times there was no visible crater.  At the time of Father Hubbard's visit to the summit no crater was found.  The small crater would become plugged when the pressure was sufficient to lift the clinkers to the crater throat but insufficient to eject them.\r\n   \"The highest point we reached, 6,500 feet, was on a line up the northwest shoulder of the mountain.  From that elevation at 10:30 a.m. on May 21 mild explosions were noticed and pumice fragments were scattered over the north slope.  Several times, sounds that closely resembled the noise produced by rocks falling into a deep narrow crater were heard coming from within the mountain.\r\n   \"As Shishaldin's flanks are always covered with snow and ice, the hot cinders erupted produced mud flows.  During such mud flows, the source of Clinker Creek may be said to be the summit of the mountain, as most of the material of the mud flow course shown in figure 2 finds its way into Clinker Creek drainage.  When the volume of the mud flow was especially large, part of the material overflowed into the next creek to the east.\"","StartYear":1932,"StartMonth":2,"StartDay":1,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1932,"EndMonth":5,"EndDay":21,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":563,"Name":"Amukta 1932/3","Description":"   Newspaper accounts of a possible eruption at Amukta Volcano in 1932 are as follows:\r\n   From the Associated Press, March 1, 1932: \"The crew of the motorship Eunice here [Dutch Harbor, AK] from the west, reported Amukta Island was throwing out a dense cloud of smoke and ashes over the water.\"\r\n   From the International News Service, March 1, 1932: \"Spouting smoke and ashes for the first time in modern history of any of the present residents of Amukta Island volcano in the Aleutians group today went into action.  Seismologists and geologists said it was the initial reuption of the volcano as far as they could ascertain.\"","StartYear":1932,"StartMonth":3,"StartDay":1,"StartTime":null,"StartQualifier":7,"StartQualifierUnit":"Days","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Amukta","ParentVolcano":"Amukta","VolcanoID":"ak10","ParentVolcanoID":"ak10"},{"ID":43,"Name":"Kanaga 1933","Description":"   Coats (1950) specified that Kanaga was \"active; type of activity unspecified\" in 1933.  However, newspaper articles from that time period specify that \"Great Sitkin volcano\" on \"Kanaga Island\" was in eruption at this time.  A few articles are more clear, stating that \"reports from Kanaga Island\" state that Great Sitkin was in eruption.  It seems likely that reports of Kanaga erupting in 1933 are erroneous.","StartYear":1933,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kanaga","ParentVolcano":"Kanaga","VolcanoID":"ak144","ParentVolcanoID":"ak144"},{"ID":424,"Name":"Iliamna 1933/5","Description":"   From Anchorage Daily Times (1933): \"Capt. Heine Berger of the motorship Discoverer, now in port, reports that when the ship passed within close range of Mt. Iliamna about three days ago the peak no longer was throwing smoke.  On the trip before, or about ten days ago, it was throwing volumes of smoke from three vents.  This time, says the captain, no smoke whatever was visible and the weather was clear.\"\r\n   From the Nome Nugget (May 8, 1933): \"Mount Iliamna, which has been smoking through one funnel, is now billowing black smoke in three places.  There is an entirely new funnel on the East side.\"","StartYear":1933,"StartMonth":5,"StartDay":3,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1933,"EndMonth":5,"EndDay":10,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":438,"Name":"Redoubt 1933/5","Description":"   Till and others (1993) summarize this event as follows: \"Following an earthquake in May 1933, Redoubt was observed 'belching smoke,' which was unusual since it 'had never been known to emit anything more than a slight wisp of smoke' (Fairbanks Daily News-Miner, May 25, 1933).  The report does not mention tephra or that the smoke was dark in color.  Hence, it seems likely that the activity was water-vapor emissions rather than an eruption.\"\r\n   Newspaper accounts of this event state that Captain Heine Berger, of the Discoverer, brought word of earthquakes in the region in early May, along with cracks in the ground up to several hundred feet long, and news that Mt. Redoubt was \"smoking.\"","StartYear":1933,"StartMonth":5,"StartDay":5,"StartTime":null,"StartQualifier":10,"StartQualifierUnit":"Days","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Redoubt","ParentVolcano":"Redoubt","VolcanoID":"ak231","ParentVolcanoID":"ak231"},{"ID":51,"Name":"Great Sitkin 1933/11","Description":"   Coats (1950): Minor explosive eruption at Great Sitkin in 1933.  Hantke (1951) reports an eruption in Nov. 1933.  Numerous newspapers reported an eruption at the end of November, 1933.","StartYear":1933,"StartMonth":11,"StartDay":30,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":588,"Name":"Shishaldin 1935","Description":"   Edward Weber Allen, in his 1936 book about his 1935  journey to Japan, Siberia, Alaska, and Canada, aboard the Santa Ana, seems to describe possible eruptive activity at Shishaldin - perhaps hot or molten lava within the crater.  The text of his account is as follows: \"The sky almost cleared and the late sun, setting tardily, silhouetted the volcanic cone of Shishaldin symmetrically.  Dark and ominous it loomed.  Dense smoke poured forth from its dull-glowing top.  Its spell lured us with a mysterious, diabolical enchantment.\r\n   \"Then the sun set, completely disappearing to the northwest, leaving a pinkish tinge upon the few fleeting clouds that still remained.  A new moon came drifting silently into the star-lighted heavens, its pale glimmer futile against the night.  The huge hulk of Shishaldin towered ever bigger, darker, and more fascinating in the magnifying power of the dusk.  At last all was wrapped in the night's secretive dimness except the weird volcanic glow that seemed floating in the sky.  Brain and body almost benumbed by the overwhelming tenseness of watching this gigantic scheme, we silently turned away and sought for rest.\"","StartYear":1935,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":342,"Name":"Augustine 1935/3","Description":"   The Anchorage Daily Times published at least two articles in 1935 concerning an eruption at Augustine.  The first, published April 3, states: \"Augustine Island * * * is a roaring volcano, hurling a mighty volume of smoke into the heavens, pounding thousands of tons of lava down the sides into the sea and hurling dust over the areas for a radius of seventy miles.\r\n   \"News to this effect was brough yesterday by Pilot Roy Dickson of the Star Air Service, returning here from that vicinity, after flying over and around the roaring inferno, accompanied by George L. Johnson of this city.  Mr. Johnson took a moving picture of the volcano in action.\r\n   \"Dickson and Johnson describe Augustine as one of the most awe-inspiring and magnificent sights they ever witnessed.  Huge clouds of vapor are rising from the high cone, oozing from a main rupture in the center of the peak, and from cracks at various places about the top.  The cone has an altitude of 3900 feet above the sea.\r\n   \"The Augustine rises cone shaped sheer from the waters of the sea * * * having only a narrow border of land about the bottom, where for a long time wild strawberries have thrived.  Now they are buried under the flood of lava and deposit of ash, and the material pouring down the steep sides pours into the sea at many places.  Huge pieces of black material, lava or other light substance from the cone float on the waters.\r\n   \"The smoke seems to be blowing chiefly toward Bristol Bay.  Dickson and Johnson visited the voclano several days ago, flew over and around it several times, and attempted to return, but cloudy weather prevented the return.  They flew there from Iliamna.\"\r\n   On July 13, The Anchorage Daily Times reported: \"Contours of the famous Augustine volcano near Kamishak Bay have changed since it started erupting this summer, William Berry, fishing warden, said last night.\r\n   \"Mr. Berry said the eruptions have blown off sections of the cone so that it no longer is of perfect symmetry.  He told of lying off the island several days in his boat and watching the volcano.  The lava spurts into the air continually and rolls down the side of the mountain.  At night it looms up red from the molten rock.  Steam and smoke blows out of the cone, he said.  Mr. Berry brought some excellent snapshots of the volcano in action.\"\r\n   From Kienle and Swanson (1985): \"Detterman (1963) reports that the eruption started on March 13 and ended August 18.  In mid-August a tall black eruption cloud, 10 to 30,000 feet (3 to 9 km) high, rather thin and not billowing out at the top was seen by Mr. Wahleen (personal communication) from aboard the S.S. Dellwood just after leaving False Pass on a great circle route to Seattle.  Since no other eastern Aleutian volcano was active that year, it seems that Mr. Wahleen saw the final major eruption of Augustine Volcano on August 19, from a distance of about 800 km.  Between March and August, minor and major eruptions were also observed from the west side of Cook Inlet.  Considerable amounts of tephra were erupted, and pyroclastic flows and mudflows were concentrated on the northeastern and southwestern flanks of the volcano (Detterman, 1963).  The 1883 dome described by Becker (1895) was presumably destroyed during the initial vent clearing eruption * * * Finally, two new lava domes were emplaced in the summit crater.\"\r\n  Waitt and Beget (2009) additionally confirm the existence of the 1935 lava dome: \"Remnant of a 1935 dome of gray porphyritic andesite forms a prominent point on the north-northwest of the summit dome complex [unit 35d, plate 1; fig. 16 in original text] and a broad dome lobe that descends the west-southwest summit cone. The 1935 dome is identified by several sources: (1) contemporaneous shipboard photographs taken by Kenai Peninsula resident Steve Zawistowski in July 1935 showing the steaming west-southwest lobe [fig. 46 in original text]; (2) USGS oblique aerial photographs taken in 1944 by John Reed, in 1959 by Bruce L. Reed, and in 1960 by Austin Post -- all before large changes to the summit area during the 1963-64 and 1976 eruptions; and (3) Detterman (1968, 1973), who in 1967 in the field distinguished the then-new 1963-64 dome from remnants of older domes. The 1944, 1959, and 1960 photographs actually show two domes: one (1883) inside the 1883 crater, the other (1935) on and outside the west rim [see fig. 45 in original text].\"\r\n   Waitt and Beget (2009) also confirm the flank deposits: \"High on the southwest flank downslope of the 1935 dome heads a fan of rubble whose angular andesite dome-rock boulders are as large as 6 m [see unit 35b, plate 1 in original text]. This material is similar to coarse lithic pyroclastic-flow deposits on the south flank of the 1963-64 eruption. Because the southwest fan lies directly downslope from the 1935 dome, we interpret it to have been emplaced then.\r\n   \"Zawistowski’s July 1935 photographs from a boat off the southwest coast show light-colored fresh deposits in west-southwest swale, clearly recently shed downslope from a steaming, active dome [see fig. 46 in original text]. Some of the pyroclastic-flow deposits in this broad swale that we map with the 1964 eruption may include indistinguishable similar coarse debris from 1935.\"","StartYear":1935,"StartMonth":3,"StartDay":13,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1935,"EndMonth":8,"EndDay":18,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":559,"Name":"Okmok 1935/12","Description":"   A UP article recounts a probable eruption of Okmok, on December 20, 1935.  \"Seward, Alaska - Dec. 30 - (UP) -- Violent eruption of Mt. Tulik, active volcano on nearly uninhabited Umnak Island in the Aleutian Archipelago was reported today by Capt. Chris Trondsen of the steamer Starr, who reached Seward after a cruise along the islands.\r\n   \"Capt. Trondsen said great streams of flaming lava were pouring out of the cone of Mt. Tulik Dec. 20, and the sky for miles was red with the glare.  There are no villages near the mountain.\"","StartYear":1935,"StartMonth":12,"StartDay":20,"StartTime":null,"StartQualifier":14,"StartQualifierUnit":"Days","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Okmok","ParentVolcano":"Okmok","VolcanoID":"ak206","ParentVolcanoID":"ak206"},{"ID":167,"Name":"Okmok 1936","Description":"   Coats (1950) reports smoke at Okmok in 1936.","StartYear":1936,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Okmok","ParentVolcano":"Okmok","VolcanoID":"ak206","ParentVolcanoID":"ak206"},{"ID":205,"Name":"Pavlof 1936","Description":"   Various compilers break the time period of 1938-1948 into several different eruptions, or one continuous eruption.  Jacob and Hauksson (1983) assert that during this time period Pavlof was in nearly continuous minor explosive eruption, with \"significant eruptions in 1936, July 1937, and 1942.  Lava flow may have been extruded in May 1948.  Otherwise, minor, nearly continuous ash emissions.  Photo taken in 1942 shows 1911 fissure no longer present (the wound had been healed), and a single cinder cone on upper NE flank (moat between this cone and summit, but flanks of cinder cone merged with Pavlof proper elsewhere.)\"\r\n   From Kennedy and Waldron (1955): \"Major explosive eruptions occurred in 1936 and early in 1942; during the intervening period the emission of ash-laden steam was almost continuous.  Reports by Army and Navy fliers indicate almost continuous discharge of smoke from the crater since 1942.  Activity was probably less during the summer of 1946 than at any time during the preceding 4 years.\"\r\n   Coats (1950) reports: 1936 minor explosive eruption, 1937 July minor explosive eruption; 1945 smoke; 1942 major explosive eruption; 1947 smoke; 1948 May lava flow?, minor explosive eruption\r\n    From Hantke (1955): \"July 1937 multiple big ashfalls over \"Half-Island, Alaska\", 1947 smoke, May 1948 explosive activity and probably lava flows.\"\r\n   From Hantke (1951):  June 6, 1945, weak explosions with steam and ash emissions every minute from small summit crater\r\n   Robinson (1948) reported that in 1945 Pavlof was \"mildly active, puffs of black ash and steam at ~1min intervals.\"\r\n   Meredith (1998) writes that Pavlof \"showered the country with ash\" in 1937, and that on September 20, 1946 \"Mt. Pavlov blew out spurts of smoke and ash.\"  She reports that she asked \"one of the men if he worried about living so close to an active volcano.  'No,' he said, 'we just call him Mount Puff-Puff.'\"","StartYear":1936,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1948,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":478,"Name":"Mageik 1936/7","Description":"   From Fierstein and Hildreth (2001): \"The supposed eruption of Mount Mageik listed for 1936 appears to be based wholly on a romantic travel book (Hutchison, 1937) that mentions a brief call by the SS Star at Halibut Bay on the southwest corner of Kodiak Island, 95 km south of Mount Mageik.  Although the writer did not land, the captain 'brought back some interesting specimens of pumice stone with which the water of the were sprinkled as well as the shore.  It had been vomited from the crater of the giant Mageik * * * on the 4th and 5th of July, a week previous to our visit.'  The floating pumice was, of course, that of 1912, which lines the beaches of Shelikof Strait to this day.\"\r\n   They also state: \"Not a single one of the 20th century tephra eruptions of Mageik listed in Simkin and Siebert's (1994) \"Volcanoes of the World\" seems plausible.  Configuration of the crater has not changed since it was first photographed in 1923; there are no juvenile ejecta in the crater or around its rim (except a scattering of 1912 pumice clasts from Novarupta); and the only late Holocene fall deposits on the or near the lower flanks of Mageik are the Novarupta pumice falls of 1912 and the black Trident ash of 1953.\"","StartYear":1936,"StartMonth":7,"StartDay":4,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1936,"EndMonth":7,"EndDay":5,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mageik","ParentVolcano":"Mageik","VolcanoID":"ak187","ParentVolcanoID":"ak187"},{"ID":103,"Name":"Yunaska 1937/11","Description":"   From the Anchorage Times (1937): \"The weather bureau here [Seattle] said today [November 3)  it received a radiogram from the Bureau of Education ship Boxer describing a violent volcanic eruption on Yunaska Island in the Aleutian chain west of Unalaska.  The Boxer said it passed 15 miles northwest of Yunaska and that the island was in flames from the eruption.  The disturbance seemed to be the most violent in the center, diminishing on the east and west ends.\"\r\n  A UP article published in the Nevada State Journal states that Isak Lystad, captain of the Boxer, reported the eruption sighted on November 2, and that \"explosions could be heard from hundreds of miles\" and that \"smoke, fire, and ashes were ballooned thousands of feet into the air.\"","StartYear":1937,"StartMonth":11,"StartDay":2,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1937,"EndMonth":11,"EndDay":4,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Yunaska","ParentVolcano":"Yunaska","VolcanoID":"ak329","ParentVolcanoID":"ak329"},{"ID":145,"Name":"Makushin 1938/6","Description":"  Coats (1950) reports an ash eruption from Makushin in October, 1938.  However, the Anchorage Daily Times, in October 1938 reports that the Coast and Geodetic Survey was in the Aleutian Islands during the summer of 1938, and that the crew reported \"the most violent eruption with great clouds of smoke rising from its crater.\"  Therefore it seems likely that the previously cited October date for this eruption is inaccurate and that the observed volcanic activity actually took place sometime during the summer.","StartYear":1938,"StartMonth":6,"StartDay":null,"StartTime":null,"StartQualifier":3,"StartQualifierUnit":"Months","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":289,"Name":"Cleveland 1938/6","Description":"   The Anchorage Daily Times (1938) reported that during the summer of 1938, \"officers of the U.S. Coast and Geodetic Survey ships Surveyor and Pioneer said that \"Mount Cleveland, on Chuginadak, one of the islands of the Four Mountains, which pokes its snowy head to a height of 8,500 feet, was emitting smoke and steam.\"\r\n   The Fairbanks Daily News Miner reported activity in July, 1938: \"Indications of the eruption of Mount Cleveland on Chuginadak island are reported by a party of men at Pioneer Camp.  \r\n   \"In a wireless message to Dutch Harbor the members of the party report seeing sparks and hearing rumblings.\r\n   \"The extent of the eruption is now [not?] known.\"","StartYear":1938,"StartMonth":6,"StartDay":null,"StartTime":null,"StartQualifier":2,"StartQualifierUnit":"Months","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":168,"Name":"Okmok 1938/7","Description":"   The Anchorage Daily News reported on October 20, 1938, that U.S. Coast and Geodetic Survey crews of the ships Pioneer and Surveyor had reported \"Mount Tulik on Umnak Island\" active during the summer of 1938.  The deeply glaciated nature of Mount Tulik (Coats, 1950; Miller and others, 1998) indicates that it has not been active within historic time.  Eruptions attributed to Tulik are almost certainly eruptions at Okmok instead.  Coats (1950) reports this eruption as occurring in October; this date probably references the date of the newspaper article and not the date of the eruption, which seems to have occurred sometime during the summer months.  Powers (1958) reports a lava flow associated with this eruption, as well.","StartYear":1938,"StartMonth":7,"StartDay":null,"StartTime":null,"StartQualifier":2,"StartQualifierUnit":"Months","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Okmok","ParentVolcano":"Okmok","VolcanoID":"ak206","ParentVolcanoID":"ak206"},{"ID":310,"Name":"Veniaminof 1939/5","Description":"   From Miller and others (1998): \"On May 29, 1939, a series of explosions began that lasted until at least June 26, 1939; a U.S. Coast Guard cutter offshore reported an ash cloud to 6,100 m with 450 m high 'flames.'  Ash from the eruption reportedly reached an average depth of 2-5 cm over a 84-km radius; most residents of Perryville, 35 km south of the volcano, were evacuated (Perryville was established in 1912 by relocation of the former residents of the village of Katmai.)\"\r\n   Various newspaper articles, from May 29 through June 17 chronicle the eruption.\r\n   May 30, 1939 (UP): \"today * * * Mt. Veniamin spewing hot ashes over nearby native settlements.\r\n   \"Minor earth tremors throughout the peninsula accompanied the volcanic outbreak.\r\n   \"The tiny settlement of Chignik reported that ashes had rached a depth of two feet and that the air was so filled that it was twilight most of the long near Summer day. * * * First reports of the eruption, whicih began last week, came from the captain of the lighthouse tender Cedar to the weather bureau here [Juneau].  * * * The captain said a thirty five mile wind was carrying heavy ash from the volcano far out to sea.\r\n   \"Smoke began to stream from Mt. Veniamin last week and  yesterday huge clouds of black smoke and ash billowed forth. * * * Several weeks ago earthquakes of great intensity were reported from the north Pacific regions, possibly in the Gulf of Alaska off the Alaskan peninsula.  Experts believed the quakes were a prelude to the volcanic activity of Veniamin.\"\r\n   June 5, 1939 (AP): \"A radio message today said Mount Veniaminof, an Alaskan peninsula volcano, was again erupting on a violent scale.\r\n   \"The message came from Mr. and Mrs. A.D. Johnson, only white residents of Perryville, Alaska, near the volcano.\r\n   \"Veniaminof's recent nine-day outburst frightened the Indians, so severely that all but one native family fled.\r\n   \"Johnson's message said: 'Sky cleared this morning. Volcano could be seen plainly.  Was belching fire to greater heights than any time during the eruption.  More hot ashes falling.'\"\r\n   June 8, 1939 (UP): \"Perryville, Alaska.  June 7.  Fear and help reached this tiny fishing village in the shadow of smoking Mount Veniaminof simultaneously Wednesday.\r\n   \"The fear arose from indications the wind was shifting, bringing a threat of deluging the village and its two remaining families, one white and the other native, with hot cinders and stifling fumes from the awakening volcano.\r\n   \"Ashes blow to sea.  So far the prevailing wind has been southerly, blowing the ashes and fumes into the Bering Sea to the north of this Alaska peninsula village.  A shift to the northwest would bring the deluge, A.D. Johnson and his wife, village school teachers, feared.\r\n   \"* * * The Coast Guard cutter Haida was standing off the village, ready to remove the two families if necessary. * * * There were increasing earth shocks Wednesday.  Some were so violent they sent dishes crashing to the floor and turned around furniture in the Johnson home.\"\r\n   June 12, 1939 (AP): \"A thick black sediment, believed by residents to be volcanic ash from erupting Mount Veniaminof, 1,000 miles away in Alaska, covered this section [Toledo, Oregon] of the Oregon coast at dawn Sunday. \r\n   \"The ash was tracked into countless homes and sent hundreds of automobiles to wash racks.  The mysterious 'dirt' was deposited by fog.\"\r\n   June 15, 1939 (AP): \"A new eruption of Mount Veniaminof, mile-and-a-half high Aleutian peninsula volcano, spread volcanic ashes over a wide area of land and sea today.\r\n   \"The motorship Fern, which gave a position offshore about 35 miles from the mountain, radioed at 11:15 pm last night the volcano was again in violent activity.\r\n   \"Ash and sand was falling on the ship's decks, the message said, and visibility was cut down to about a mile.\r\n   \"The volcano has been active since May 23 and A.D. Johnson, radio operator and government school teacher at Perryville, 20 miles to the south, has radioed frequently of its eruption.\"","StartYear":1939,"StartMonth":5,"StartDay":29,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1939,"EndMonth":6,"EndDay":26,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Veniaminof","ParentVolcano":"Veniaminof","VolcanoID":"ak301","ParentVolcanoID":"ak301"},{"ID":314,"Name":"Veniaminof 1939/11","Description":"   Coats (1950) reports a minor explosive eruption at Mount Veniaminof in November, 1939.","StartYear":1939,"StartMonth":11,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Veniaminof","ParentVolcano":"Veniaminof","VolcanoID":"ak301","ParentVolcanoID":"ak301"},{"ID":425,"Name":"Iliamna 1941","Description":"   Juhle (1955) writes that Coats (1950) listed Iliamna with \"steam and rumble\" in 1941.  However, Coats (1950) does not reference any event for Iliamna in 1941, but does list \"smoke\" for Iliamna in 1947.","StartYear":1941,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":44,"Name":"Kanaga 1942","Description":"   Hantke (1951) lists an eruption at Kanaga in 1942.","StartYear":1942,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kanaga","ParentVolcano":"Kanaga","VolcanoID":"ak144","ParentVolcanoID":"ak144"},{"ID":315,"Name":"Aniakchak 1942","Description":"   Eruption is uncertain (Smithsonian Institution, 2002-, accessed March 28, 2007).","StartYear":1942,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":743,"Name":"St. Paul Island 1943/3","Description":"A very uncertain possible eruption account of a submarine eruption offshore of St. Paul Island in the Pribilof Island is contained in Lyman Ellsworth's 1952 memoir, titled \"Guys on Ice.\"\r\nBelow is an excerpt from the book, describing events of March 17 - 20, 1943, as viewed from the village on St. Paul, where he and other soldiers were stationed during WWII.\r\n\r\n\"We jogged along till the morning of St. Patrick's Day (1943). Things were quiet when Sergeant Graves careened down the hill into the village, yelling \"Smoke out to sea to the south!\"\r\n\tSmoke! It must be from an icebreaker. The ice was solid as far south as we could see. Dutch Harbor hadn't passed any word about an icebreaker being in this area. Then I remembered the Russian vessel at St. George. Perhaps this was another Russian ship. Graves said he had watched it for some time before he came down. No use to say he'd been seeing things; it was smoke all right, and it was off to the south. \r\n\tThere was a general exodus from the hotel to the top of the hill to see what could be seen. Graves was right. South of Otter Island a tall plume of smoke was streaming into the sky. \r\n\tAll that day it hung there in that same position. It thinned slightly at times; then for a while it would billow up into the sky in puffs. It reminded me of explosions of black feathers. \r\n\tIt certainly must be an icebreaker - what else could it be? - but it seemed queer that an icebreaker would be using up fuel so extravagantly. At times you'd think it was an oil well afire. \r\n\tWe kept watch on it throughout the afternoon. It never seemed to move away from one spot. Maybe the ice just there was especially tough. \r\n\tI considered sending a message to Dutch Harbor to see if they could tell us anything. I decided against it. I had a hunch that by now Dutch Harbor would appreciate a little vacation from St. Paul Island and its affairs. \r\n\tThe next morning after breakfast most of the detachment climbed the hill again. The smoke was still there. Gigantic puffs of it, seemingly mixed with steam, still billowed into the air. All of a sudden it came to me. \r\n\tThis was something very few people got the opportunity to see. I believed it had all the earmarks of undersea volcanic activity. Nobody believed me. None of them had ever heard of underwater volcanic activity. I explained why I was convinced.\r\n\tFor one thing, we observed dark rings, surrounded by white streaks. The white streaks would be steam, the black rings smoke. It must be plenty hot out there for them to be able to force their way up through the ice and water. If only we had a plane - it must be something to see from overhead. The action must be melting a huge ring in the ice pack. An aerial photo would be a curiosity worth having. \r\n\tThe men were skeptical. I pointed out that they must have heard of volcanic islands. For instance, Bogoslof? That had been formed by underwater volcanic action. Where was it? Just north of Umnak Island, in the Aleutians. On some older maps it was marked as the disappearing island. Why? Because it did just that. The last time it had come up out of the sea it had two peaks; one higher than the other. Prior to that it had only one. \r\n\tSomeone wanted to know what brand of baloney this was, trying to hand them the idea that an island could pop in and out of the sea like a jack-in-the-box.\r\n\tI admitted that it might sound queer, but scientists had an explanation. They figured that such an island rested on a geological formation shaped like a wedge. While the pressure was up, the island stayed above water; when the pressure fell, the island sank. I reminded them that the Aleutians still held a lot of active volcanoes.\r\n\tAnd was it an actual fact, this Bogoslof Island did disappear and reappear? \r\n\tYes, it had happened a couple times that I knew of. The island wasn't along a route much traveled in peacetime, but it had been pretty well established as fact by reports from reliable observers. Most ships tried to give the place a wide berth. \r\n\tThey were beginning to be more convinced that this smoke off to the south might be from volcanic action. I decided to message Dutch Harbor, giving them the location of the smoke from the village. They could warn any shipping; otherwise some vessel might get fouled up with a new reef. \r\n\tBerkeley groaned and growled because he didn't have a movie camera and the means of getting out there. The devil with a movie camera! I was only glad the thing hadn't started up under this island - closed in behind the ice pack we'd be in a hell of a pickle!\r\n\tSomeone said \"What a country; if you're not freezing, you're frying!\"\r\n\tIrrelevantly Van Meter commented that he had seen a hula girl once on Waikiki, hotter than any volcano. Swede advised him not to brag; bad for the blood pressure. \r\n\tThe smoke continued for three days and then slowly died away. For several days we noted a haze in the same position. Finally that too died away.\"","StartYear":1943,"StartMonth":3,"StartDay":17,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1943,"EndMonth":3,"EndDay":20,"EndTime":null,"EndQualifier":2,"EndQualifierUnit":"Days","Volcano":"St. Paul Island","ParentVolcano":"St. Paul Island","VolcanoID":"ak264","ParentVolcanoID":"ak264"},{"ID":169,"Name":"Cone A 1943/6","Description":"   From Grey (2003): \"Servicemen stationed at Ft. Glenn [U.S. Army base established on Umnak Island in 1942 and decommissioned in 1950) would occasionally trek into Okmok caldera looking for adventure as evidence by the occasional spent shells found on the caldera floor.  One sunny afternoon in June 1943, two GI's drove up to the caldera rim near the base of Tulik cone and rappelled down to the crater floor, probably between the sites of the small intracaldera glacier and Cone F (Keller, 1976 and 1991).  After spending the day hiking across the caldera, one of the men twisted his ankle on their way back and they were forced to spend the night inside the 'Devil's Brewpot.'  Mr. Keller's account of their overnight experience follows:\r\n   \"'A trembling of the earth woke me, and the whole crater was alight with a rosy glow.  That was a horrible awakening!  Right inside a volcano, and it was coming to life!  There was a deep, rumbling sound, and a nearby cone was hissing.  About that time another cone some distance away burst forth with a magnificent display of pyrotechnics * * * By the time we reached the cliff the shaking had abated, but rocks were rolling down the steep incline to the bottom * * * A fine black ash began drifting down upon us, and as suddenly as it had begun, the shaking stopped.  The rosy light faded away and the crater resounded with a deafening silence.'\r\n   \"Though this was a minor eruption, it was enough to terrify the two men, who based on Keller's description were approximately 4 km away from Cone A, the vent that had the brief fountaining (again, from Keller's description) event.  The cone they heard hissing was probably Cone C, which is near the location where they descended into the crater and still has active fumaroles at its summit (field observations, 2001).  Alternatively, it could have been sound from Cone A reverberating off of Cone C or the caldera wall.\"","StartYear":1943,"StartMonth":6,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cone A","ParentVolcano":"Okmok","VolcanoID":"ak56","ParentVolcanoID":"ak206"},{"ID":565,"Name":"Kiska 1943/6","Description":"   Although newspaper articles in June, 1943 state that U.S. pilots bombing Kiska observed \"sulfur boiling,\" dark smoke, and \"lava streams running down the the slopes into the valley\" it is likely that only fumarolic activity occurred, as Coats visiting the volcano in 1947 was unable to find any recent-looking lava.\r\n   Miller and others (1998) summarizes from Coats (1961):  \"Coats briefly visited Kiska volcano in 1947 and found no evidence of recent ash flows nor any active fumaroles; the youngest lava flows were more heavily vegetated at any given altitude than counterparts on adjacent islands known to have been erupted in the 20th century.  The youngest lava flows before 1962 were probably between 100 and several hundred years old.  Coats concluded that any events between 1905 and 1947 were at most solfataric.\"","StartYear":1943,"StartMonth":6,"StartDay":6,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kiska","ParentVolcano":"Kiska","VolcanoID":"ak161","ParentVolcanoID":"ak161"},{"ID":369,"Name":"Augustine 1944","Description":"   Barrett (1978) notes that in 1944 a small lava dome was discovered forming in the crater.","StartYear":1944,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":317,"Name":"Veniaminof 1944/3","Description":"   Coats (1950) reports a mild ash eruption at Mount Veniaminof on March 28, 1944. \r\n   A March 15, 1944 Associated Press article states \"The volcano of Veniaminoff has erupted again, passengers aboard a boat arriving from Chignik village reported today.  The resultant fireworks lighted the surrounding country, said those who had witnessed the phenomenon.\"","StartYear":1944,"StartMonth":3,"StartDay":15,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Veniaminof","ParentVolcano":"Veniaminof","VolcanoID":"ak301","ParentVolcanoID":"ak301"},{"ID":290,"Name":"Cleveland 1944/6","Description":"   The eruption is summarized by Miller and others (1998) as follows: \"The 1944 eruption was characterized by two days of Vulcanian explosive activity from the central crater, which produced lava flows as well as tephra (Simkin and Siebert, 1994).  Severe earthquakes were felt throughout the episode.  Clouds of steam and ash rose to 6000 m and lava flows extended 5 km from the central crater.  Boulders 'as big as automobiles' were ejected across the island and for a considerable distance into the surrounding ocean (Alaskan Sportsman, 1944; Freiday, 1945).  This eruption of Mt. Cleveland has the infamous distinction of having resulted in the only reported historical fatality [directly] attributable to volcanic activity in Alaska.  A small detachment of the Eleventh Army Air Force was stationed on Chuginadak Island and one soldier who apparently advanced too close to the active vent during a reconnaissance investigation was killed (Smithsonian Institution, 1985); the soldier was possibly killed by a mudslide (Lowney, 1946).  Army personnel and equipment were evacuated from the island and the outpost was abandoned for the duration of the war (Anchorage Daily Times, June 26, 1944; Robinson, 1948).\"\r\n   Silk (1944) reports on the eruption as follows: \"Sgt. Purchase left the station [outpost on Chuginadak Island] at 10 a.m., apparently for a short hike.  He carried only a rifle and two or three clips of ammunition, no water or rations, and he was lightly dressed.  Stg. Purchase enjoyed the outdoors and made short hikes around the island quite often.  He was beyond a doubt physically and the most capable man at the station, and was much better acquainted with the island than the other men.\r\n   \"At 10:20 a.m., the remaining men at the station noticed occasional small earthquakes, and on looking at Mt. Cleveland, about three miles away, they discovered it was smoking.  Two of the men immediately set out to find Sgt. Purchase.  They saw him at a long distance up the beach but were unable to catch up with him.  They followed his tracks along the sand until they came to the foot of the north slope of the volcano.  Just as they reached this point they noticed a small flow starting down the hillside.  Thinking that Sgt. Purchase would also be attracted by this flow, the men left the beach and went up the hill to observe the flow more closely.\r\n   \"It was discovered that the flow consisted mainly of mud, water, ash, and small rocks.  Very shortly after this, the men, looking up the slope, observed a long lava flow starting down which threatened to cut across the return path, so they gave up their search and returned to the cabin, well knowing that Sgt. Purchase could take care of himself.\r\n   \"They were not very worried over his absence until he failed to appear for the evening meal.  It was then that they sent the message stating that he was missing.  In the meantime the first flow had reached the sea and cut off his return path in that direction.  They then received an answer to their radioed message for help, in which they were ordered to remain at their cabin, and they were not to attempt to locate the missing man and thereby take a chance of losing more men until relief arrived.\r\n   \"The story at this point is taken up by Lt. Lynn Cunningham, who was on the rescue party.\"  The narrative continues, explaining how they searched fruitlessly for Sgt. Purchase.  The eruption narrative continues with: \"At about 3 a.m. on the morning of the 12th we were awakened by violent and continuous earthquakes.  We could hear a constant grumbling coming from the volcano.  But, on going outside the station, we could see nothing, so we back to bed.\r\n   \"At 7 a.m. the volcano was plainly vislble.  The sky was clear and we saw that the rim of the crater was slightly inclined to the south of the apex.  Violent eruptions were taking place, although no lava was flowing at this time.  A never-ending fountain of boulders about 20 to 40 feet in diameter were being thrown from 1,000 to 2,000 feet straight into the sky.\r\n   \"The volcano did not throw a few and then subside to build up more steam as is the usual case with volcanoes, but sprayed continuously.  The erupted rocks were rolling down the south slope.  Few, if any, rolled down the north slope.  This upheaval of rocks continued for more than 12 hours, and finally, at the height of its fury, blew the entire top off the volcano.  The eruptions at this time ceased to be directed to the south and could be seen falling in every direction.\"  The narrative reports that at 10:20 that night, a boat sent to search again for Sgt. Purchase was showered with small cinders and ash, and they \"saw the eruptions of rock cease and the flow of lava start.  It was apparently flowing evenly down all sides of the volcano.  The reflection lighted the sky a bright red for miles around.\"","StartYear":1944,"StartMonth":6,"StartDay":10,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1944,"EndMonth":6,"EndDay":13,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":146,"Name":"Makushin 1944/9","Description":"  Jacob and Hauksson (1983) report that there was strong thermal activity (on N flank?) of central cone, caldera wall, and onto caldera flank during September, 1944.","StartYear":1944,"StartMonth":9,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":52,"Name":"Great Sitkin 1945/3","Description":"   From Simons and Mathewson (1947): \"Extrusion of the crater dome marks the latest phase of activity. The dome is thought to have formed in March, 1945, at which time a glow was visible at night from Adak Island, and Army aviators noticed clouds of steam rising from the crater.  During that month a strong earthquake was felt at Sand Bay.\"  \r\n   From Coats (1950): lava flow or plug dome, some explosive activity at Great Sitkin in 1945.\r\n   Robinson (1948) includes a picture of the 1945 lava dome at Great Sitkin, captioned: \"Mass of hot lava pushing up through snow in Great Sitkin Crater, may menace a near-by Navy fueling station.  The dome of molten rock, half a mile in diameter, pushed and melted its way up through the white blanket in March, 1945, cracking the snow around its periphery.  Steam rises from snow being melted by the lava.\"\r\n   Newhall and Melson (1983) estimate the volume of this dome at about 10 x 10^6 cubic meters.","StartYear":1945,"StartMonth":3,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":170,"Name":"Cone A 1945/6","Description":"   From Grey (2003): \"The 1945 eruption was fairly well documented (Miller and others, 1998; Robinson, 1948; Wilcox, 1959; Byers, 1947).  Robinson gave a detailed account of his visit to Okmok at the request of Lt. Gen. Delos C. Emmons, Commanding General of the Alaskan Department, who was concerned for the safety of Ft. Glenn army base.  The eruption is believed to have begun on June 1, when a sharp earthquake was felt at Ft. Glenn.  Cloud cover delayed the first observation until June 4, when pilots reported black ash rising to 3000 m.  Weather precluded further observations until June 10, when the clouds and fog finally cleared.  Robinson and his fellow party members witnessed strombolian activity of Cone A from the caldera rim, along with the accompanying lava flow [see figure 4.2 in original text].  An excerpt from Robinson's description:\r\n   \"'A steady roar, like that of a railroad locomotive at the far end of a long tunnel, was punctuated every 10 to 15 seconds by a violent explosion which threw red-hot blobs of lava more than a thousand feet above the cone * * * About once a minute there was a particularly violent explosion in which bombs, some several feet long, were thrown far out on the caldera floor * * * A stream of lava, glowing red even in the bright sunlight, issued from a fissure in the southwest base of the cone, poured over a cliff as a \"lava fall,\" and turned down a depression to the northeast toward the center of the caldera * * * Near the lava vent were three miniature volcanoes only a few feet high, throwing innumerable blobs of bright orange-hot lava into the air like many-armed jugglers and giving off, with a high-pitched hiss, large volumes of faintly bluish gases.  The sides of the tiny volcanoes were spectacularly colored with white, yellow, orange, and red deposits made by the gases.'\r\n   \"Robinson's crew also noticed 5 cm of ash accumulated on the caldera rim on June 10, and observed that the lava flow rate was about 0.15 m/s, and the flow had reached 1200 m long.  By the end of the eruption, which continued intermittently until December, 1945, the main flow lobe reached about 6 km in length, with a second flow lobe about 2.5 km long to the north of the cone [see figure 1.2 in original text].  The estimated average thickness of the first lava lobe is 12 m.  Estimated lava flow volume is 1x10^7 cubic m (Reeder, 1984) to 2x10^7 cubic meters (Byers and others, 1947).  The summit of Cone A had two craters before the eruption (Robinson, 1948), whose rim heights were estimated at 150 m for the NW vent and 120 m for the SE vent.  After the eruption, the SE vent, which had been the active vent for the duration of the 1945 eruption, had grown by an estimated 30 m (Robinson, 1948).\"","StartYear":1945,"StartMonth":6,"StartDay":1,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1945,"EndMonth":12,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Cone A","ParentVolcano":"Okmok","VolcanoID":"ak56","ParentVolcanoID":"ak206"},{"ID":479,"Name":"Mageik 1946","Description":"   Coats (1950) lists a questionable explosive eruption at Mount Mageik in 1946.  Fierstein and Hildreth (2001) doubt the validity of this report, stating: \"Not a single one of the 20th century tephra eruptions of Mageik listed in Simkin and Siebert's (1994) \"Volcanoes of the World\" seems plausible.  Configuration of the crater has not changed since it was first photographed in 1923; there are no juvenile ejecta in the crater or around its rim (except a scattering of 1912 pumice clasts from Novarupta); and the only late Holocene fall deposits on the or near the lower flanks of Mageik are the Novarupta pumice falls of 1912 and the black Trident ash of 1953.\"","StartYear":1946,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mageik","ParentVolcano":"Mageik","VolcanoID":"ak187","ParentVolcanoID":"ak187"},{"ID":366,"Name":"Shishaldin 1946/8","Description":"   Robinson (1948) reported a small steam plume from Shishaldin on June 6, 1946.   Coats (1950) reports a minor explosive eruptions at Shishaldin from August - September 1946, December, 1946, and January, 1947.  Hantke (1951) reported \"ashfall over the Aleutians\" in 1946 from Shishaldin.  The January 10, 1947 edition of the Sitka Sentinel reports \"A second volcanic disturbance in Alaska's Aleutian islands was reported today by the Navy, which said 9387 foot Mount Shishaldin on Unimak Island was erupting with such violence that it showered ashes two inches deep on the village of False Pass 20 miles away. * * * The USS Passiac, a netlayer, visited False Pass January 2 and reached Dutch Harbor today with news of the new eruption.  Postmaster Frank Bell of False Pass told Passiac crewmen that Shishaldin had been erupting every five days for several weeks.\"\r\n   The Associated Press article from the January 10, 1947 edition of the Walla Walla Union-Bulletin gives a few additional details: \"Quartermaster 1-c Allan E. Sitter of Los Angeles, said he observed heavy black puffs of smoke bursting from the mountain.  False Pass residents said the eruption caused electrical disturbances which looked like lightning flashes and lighted the entire area.  Sitter said the village was covered with a two-inch coating of volcanic ash, and that cinders an inch and a half in diameter, lay on the wharf.\"\r\n   A January 11, 1947 Associated Press article describes the eruption: \"The eruption of Mt. Shishaldin * * * also was photographed from Lieutenant Kissling's plane.\r\n   \"He said cinders, smoke, and steam were spewing from an opening on the south side of Shishaldin's cone, and were being carried northward, obscuring the view of that side of the peak.\r\n   \"Shishaldin's activity, at the time, was of less intensity than had been reported by Frank Bell, postmaster at False Pass.  That village, about 30 miles east of the peak, has a blanket several inches deep of cinders and ash.\"\r\n   Meredith (1998) reports that on September 7, 1947, she could see \"Mt. Shishaldin's smoking peak about 20 miles away.\"","StartYear":1946,"StartMonth":8,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1947,"EndMonth":1,"EndDay":null,"EndTime":null,"EndQualifier":2,"EndQualifierUnit":"Months","Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":53,"Name":"Great Sitkin 1946/8","Description":"   From Byers and Brannock (1949): \"In the summer of 1946 a column of steam 4000 feet high rose from the crater.  According to R. R. Coats (personal communication), who visited the 1945 crater dome in June 1946, steam and strongly pungent gases were escaping from beneath the shattered carapace of the dome.  He did not see the orifice of the main large fumarole near the center of the dome because of the great difficulty in traversing the blocky lava.  According to Frank S. Simons (personal communication) the melting snow around the crater had a distinct sour taste late in the summer of 1946.\"\r\n   From Simons and Mathewson (1947):\"[A] small smoke cloud [from Great Sitkin] was visible from Adak Island on August 14, 1946.\"`","StartYear":1946,"StartMonth":8,"StartDay":14,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1946,"EndMonth":8,"EndDay":14,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":247,"Name":"Akutan 1946/12","Description":"   From Byers and Barth (1953): \"The most recent lava eruption of Akutan volcano was first seen on January 4, 1947, at 4 pm.  An Associated Press article dated January 8 quoted a Navy report that the lava had flowed down the sides of the volcano threatening Akutan village.  * * * Actually, inasmuch as the lava of the January, 1947, eruption did not flow out of the crater, the village was never threatened by flowing lava.  The small lava tongue that extends through the crater gap and down the crater gorge is part of the December, 1929 lava flow, according to a local resident, Axel Swenson (Finch, 1935, p. 159).\"  Specimens of the lava flow were collected and analyzed by thin section and found to be saturated calcic basalt.\r\n   Seventy-five residents were evacuated from Akutan Island in January, 1947.\r\n   A January 11, 1947 Associated Press article describes the lava flow: \"A half-mile stream of red-hot lava was described today in the first eye witness account of this week's eruptions of Akutan and Shishaldin volcanoes.  * * * Lt. P.T. Kissling, * * * piloted a long range patrol plane * * * from which J.C. Betterton, chief photographer's mate * * * photographed the spectacles.\r\n   \"Flight conditions were bad, but Lieutenant Kissling reported: \r\n   \"'Arriving over Akutan peak at dawn, the mountain presented a rare sight, in that visiblity was unlimited in the area, permitting eruptions to be observed in detail.  They (eruptions) were confined to newly-formed cone about 300 feet high within the larger crater of Akutan Peak which is three miles in diameter.\r\n   \"'A red stream of molten lava was flowing down the peak for a distance of about half mile, ending in a lake of greenish brown water formed in melted ice of the glacier.\r\n   \"'An unforgettable sight of colors was noted -- the red-orange lava and the bright orange flames from lava-flow contrasting with dirty-gray ash on the snow -- the ice in the crater -- and the pure white snow untouched by the ashes.'\r\n    \"On one flight above the cone, the plane flew through the smoke, and the cabin filled with acrid fumes.\"\r\n   And from Unknown (1949): \"* * * Akutan volcano erupted during January 1947, and a thick flood of lava covering an area one half mile square was poured out into the crater.  Very little ash fell on Akutan village then, because fortunately the wind remained in the right direction to blow the erupting ash out to sea.  At the onset of the 1947 eruption, the commandant of the Seventeenth Naval District at Kodiak ordered a Navy auxiliary tug to evacuate the villagers if necessary.\"","StartYear":1946,"StartMonth":12,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1947,"EndMonth":1,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":426,"Name":"Iliamna 1947/6","Description":"   Coats (1950) lists \"smoke\" at Iliamna in June, 1947.  This is likely just steam from Iliamna's prominent and long-lived fumaroles, and not a volcanic eruption.","StartYear":1947,"StartMonth":6,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":370,"Name":"Shishaldin 1948","Description":"   Coats (1950) reported a minor explosive eruption at Shishaldin in 1948.","StartYear":1948,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":514,"Name":"Gilbert 1948","Description":"   Byers and Barth (1953) visited Akun Island and Mt. Gilbert during August, 1948, and although they did not see \"thermal activity\" they did observe \"a faint odour resembling hydrogen sulphide,\" and viewed the sulfur products of recent fumarolic activity.","StartYear":1948,"StartMonth":null,"StartDay":8,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Gilbert","ParentVolcano":"Gilbert","VolcanoID":"ak108","ParentVolcanoID":"ak108"},{"ID":570,"Name":"Akutan 1948/8","Description":"   From Unknown (Earth Science Digest, 1949): \"During August 1948 the crater area of Akutan volcano was examined by geologists of the U.S. Geological Survey, who mapped the limits of the 1947 lava flow and of earlier lava flows.  During the geologists' visit large boulders and ash were noisily ejected from the cinder cone inside the crater at irregular intervals ranging from a few minutes to several hours.  The boulders fell over a limited area around the base of the cone, but some of the lighter ash fell on the geologists' tent pitched 3 miles from the volcano.\"\r\n   From Byers and Barth (1953): \"The activity of Akutan volcano in August, 1948, was confined to the cone inside the crater.  During successive days from August 4 to August 7, the writers had opportunity to observe the volcano close at hand for several hours.  The activity was sufficient to make unsafe any attempt to climb the cone, and indeed, even to approach within 200 yards of its base.  During the time the cone was under observation, all the major blasts came from the westernmost part of the three craterlets at the top of the cone.  At intervals ranging from one to five hours, one or two, rarely three, blasts spaced a few minutes apart would issue from this craterlet.  These major blasts consisted of a loud rush of ash-laden gas, followed by a surprisingly loud clatter of falling rocks, some of which were incandescent.  The blocks ranged in maximum dimension from a few inches to a few feet.  The average long dimension of blocks embedded in snow near the base of the cone was about six inches.\"  Byers and Barth (1953) analyzed a block ejected during the summer of 1948 and found it was calcic basalt.","StartYear":1948,"StartMonth":8,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":248,"Name":"Akutan 1949/4","Description":"   Unknown (Earth Science Digest, 1949) reports: \"* * * According to Hugh McGlashan, postmaster at Akutan, a village 8 miles east  of the volcano, 1/8 inch of ash fell on the village during the night of April 29.  Ash mixed with sleet continued to fall all during the following day because of a steady west wind from the direction of the volcano.  Now snow on the higher slopes of the volcano is covered by a heavy black layer of ash.  The eruption continued full scale until May 10 and then decreased somewhat in intensity.  \r\n   \"On May 17 several of the villagers made a closer approach to the volcano and reported hot lava flowing down the northwest slope.  Considerable steam was rising at the front of the lava where it encountered the winter blanket of snow.  This material may have been a hot mudflow, formed by lava mixing with snow, ice, and boulders inside the crater.   \r\n   \"* * * * Approximately two weeks prior to the recent eruption, three heavy earthquakes were felt at the village.\"\r\n   From Byers and Barth (1953): \"The clatter of falling rock was perhaps what had been heard by local residents as a \"crackling roar\" (Finch, 1935, p. 159) during the 1929 eruption. \r\n   \"Within a minute after the first discharge, a dark grey cauliflower-shaped cloud extending nearly a mile above the cone could be seen on a clear day.  This cloud was soon dissipated by the wind.  Frequently, the blasts were sharp enough to be termed explosions, and then resembled quarry blasts.  Some of the explosions were loud enough to be heard at Akutan village, 8 miles distant.  \r\n   \"Smaller puffs of lighter grey, ash-laden clouds [see fig. 5 in original text] occurred between major blasts at intervals ranging from a few minutes to a few hours.  Usually, several smaller puffs followed a major blast.\"  A block ejected during this time period was analyzed in thin section and found to be saturated calcic basalt.","StartYear":1949,"StartMonth":4,"StartDay":29,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1949,"EndMonth":6,"EndDay":null,"EndTime":null,"EndQualifier":3,"EndQualifierUnit":"Months","Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":503,"Name":"Novarupta 1949/5","Description":"   Eicher and Rousefell (1957) give the following account of a 1949 eruption at Novarupta: \"Following a long period of dormancy Novarupta erupted violently for approximately two hours on May 19, 1949, a heavy outfall of ash being carried down Shelikof Strait by a westerly wind (observed by senior author).\"  However, Hildreth (1983) states: \"Published compilations notwithstanding, there are no credible reports of historic eruptions in the Katmai group except at Novarupta in 1912 and at Trident in 1953 - 1968.\"  The ash seen by Eicher was probably remobilized from the 1912 eruption.","StartYear":1949,"StartMonth":5,"StartDay":19,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1949,"EndMonth":5,"EndDay":19,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Novarupta","ParentVolcano":"Novarupta","VolcanoID":"ak203","ParentVolcanoID":"ak203"},{"ID":487,"Name":"Trident 1949/6","Description":"   From Eicher and Rounsefell (1957): \"A few weeks later [after May 19, 1949] nearby Mt. Trident erupted, and it has exhibited sporadic activity almost to the present, although without significant ash outfall.\"  \r\n      However, Hildreth (1983) disbelieves this account: \"Published compilations notwithstanding, there are no credible reports of historic eruptions in the Katmai group except at Novarupta in 1912 and at Trident in 1953 - 1968.\"","StartYear":1949,"StartMonth":6,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Trident","ParentVolcano":"Trident","VolcanoID":"ak288","ParentVolcanoID":"ak288"},{"ID":54,"Name":"Great Sitkin 1949/12","Description":"   From Jones (1951): \"[S]mall ash showers and fume clouds were seen on December 30, 1949, and January 7, 1950.\"","StartYear":1949,"StartMonth":12,"StartDay":30,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1950,"EndMonth":1,"EndDay":7,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":41,"Name":"Gareloi 1950","Description":"   Jones (1951) reports that minor ash showers and fume emissions occurred during 1951 from Gareloi.  Simkin and Siebert (1994) report that this eruption began in 1950 and continued until 1951.  Jones (1952) reports that Gareloi was \"weakly active during 1950,\" and \"quieter during 1951.\"\r\n   A May 3, 1950 Fairbanks Daily News article suggests that at least some of this activity was not an eruption: \"Rear Admiral F.D. Wagner, USN, commander, Alaskan sea frontier, has received information from a naval vessel, the USS Bagaduce, that the volcano on Gareloi island, about 60 miles west of Adakin the Aleutians appears to be active.  The Bagaduce sighted large vapor clouds rising to seven thousand feet and drifting southeast at that level.\"","StartYear":1950,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1951,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Gareloi","ParentVolcano":"Gareloi","VolcanoID":"ak106","ParentVolcanoID":"ak106"},{"ID":504,"Name":"Novarupta 1950/7","Description":"   From Sumner (1952): \"In 1950 National Park Service observers discovered at its base [Novarupta's] a small new cone, perhaps fifty feet high, which apparently had been pushed up during a minor outburst of activity observed abut the first of July that year.\"  However, Hildreth (1983) states: \"Published compilations notwithstanding, there are no credible reports of historic eruptions in the Katmai group except at Novarupta in 1912 and at Trident in 1953 - 1968.\"","StartYear":1950,"StartMonth":7,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Novarupta","ParentVolcano":"Novarupta","VolcanoID":"ak203","ParentVolcanoID":"ak203"},{"ID":488,"Name":"Trident 1950/7","Description":"   From Decker (1963): \"William J. Nancarrow, the Ranger at Brooks River during 1950, mentions 3 explosive eruptions that may have been from Mt. Trident in his monthly reports for July and August, 1950: \r\n   \"'On July 2 at 2:02 A.M. a side vent of Knife [Griggs] Peak (or something in line with Knife Peak) let go and a cloud of smoke and dust was observed to rise up to 5000 feet.'  He also reports seeing a large cloud of smoke and ash rising up behind the west side of Katolinat as viewed from the Fish and Wildlife Camp on Brooks Lake on August 1, and a cloud of dust from the Valley on August 16 to 18 which cut the visibility to 2 miles and left a very thin layer of ash which 'penetrated to all corners.'\"  This eruption has been attributed to Trident by Simkin and Siebert (1994).\r\n   The Sitka Sentinel mentions in their July 11, 1950 edition that \"a new volcano was born last week in the white snows of Knife [Griggs] Mountain near the famed 'Valley of Ten Thousand Smokes.'  It was first reported July 2 by a group of fishermen.\"\r\n   However, Hildreth (1983) disbelieves this account: \"Published compilations notwithstanding, there are no credible reports of historic eruptions in the Katmai group except at Novarupta in 1912 and at Trident in 1953 - 1968.\"","StartYear":1950,"StartMonth":7,"StartDay":2,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1950,"EndMonth":8,"EndDay":18,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Trident","ParentVolcano":"Trident","VolcanoID":"ak288","ParentVolcanoID":"ak288"},{"ID":206,"Name":"Pavlof 1950/7","Description":"   Jones (1952) reported minor explosive activity from Pavlof volcano in August, 1950, \"culminating in November and continuing through the winter.\"  He also reported Pavlof active on January 15, 1951, and \"rhythmic\" explosive activity on April 1, 1951, with the volcano quiet from May until fall.\r\n   Hantke (1955) reports that on July 31, [1950] there was a sudden onset of stronger explosive activity, and \"in the following night there was glowing tephra [? Translation uncertain] to 1000 m.\"\r\n   The Syracuse Herald-Journal recorded in the August 1, 1950 edition: \"Towering Mt. Pavloff spewed a column of smoke 25000 feet into the air today above a spectacular torrent of lava.  A tiny Indian village 30 miles from the peak was threatened with burial in volcanic ash.\r\n   \"The 8900 foot peak loacked 500 miles west of Anchorage, blew its top yesterday * * *.\"\r\n   Lachland MacDonald (1950) described the eruption a little differently: \"Mount Pavlof was belching smoke 20,000 feet into the air.  Fine ash covered an area of 30 miles and visiblity was impaired.\r\n   \"First reports of the eruption, classed as a minor one by the experts, came from pilots on July 31.  They spotted flames and lava pouring from a crater on the northeast slope.  One witnessed chunks of pumice thrown hundreds of feet into the air and another described alternate coughing of steam and smoke punctuated by spurts of fiery lava.\"","StartYear":1950,"StartMonth":7,"StartDay":31,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1951,"EndMonth":5,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":57,"Name":"Great Sitkin 1950/11","Description":"   From Jones (1951): \"No fume or ash clouds have appeared from Great Sitkin since the series of eruptions which ended about November 29, 1950.  During this eruptive period, which began November 5, 1950, several ash showers and fume were produced.  Jones estimated that one ash eruption produced possibly as much as 20,000 cubic meters of ash.  Flashes of light were observed several times at night by military personnel on Great Sitkin Island, but they were not seen from Adak.\"","StartYear":1950,"StartMonth":11,"StartDay":5,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1950,"EndMonth":11,"EndDay":29,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":47,"Name":"Kanaga 1951","Description":"   Jones (1951) reported \"Minor ash showers and fume emission are known to have occurred during 1951 from Gareloi, Kanaga, Great Sitkin, Akutan, and Shishaldin.\"","StartYear":1951,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kanaga","ParentVolcano":"Kanaga","VolcanoID":"ak144","ParentVolcanoID":"ak144"},{"ID":55,"Name":"Great Sitkin 1951","Description":"   From Jones (1951): Minor ash showers and fume emissions are known to have occurred during 1951 from Great Sitkin.","StartYear":1951,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":454,"Name":"Kukak 1951","Description":"   From Siebert and Simkin (2002-, accessed March 23, 2007): \"[R]eports of historical eruptions at Kukak from Hantke (1959) appear to be erroneous. The report of a 1951 eruption is an apparent reference to a July 22, 1951 ashfall at Kukak Bay, which was attributed by Muller and others (1954) to Martin volcano.\"  Miller and others (1998) doubt that Martin has had any historic eruptions either, stating: \"all reports of eruption or ash emission [from Martin] are probably spurious, reflecting only the persistent and conspicuous steam plume.\"\r\n   Hantke (1959): Kugak \"probably had an ash eruption in 1951.\"  The July 22 date appears to belong to an event in 1953 (Muller and others, 1954; Hantke, 1959) rather than this 1951 event.","StartYear":1951,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kukak","ParentVolcano":"Kukak","VolcanoID":"ak174","ParentVolcanoID":"ak174"},{"ID":372,"Name":"Shishaldin 1951/4","Description":"   Jones (1952) reported that during April, 1951, \"on a moonlit night, glow was reflected high above Shishaldin volcano, the most active vent on Unimak Island.\"  He also reports that during July, 1951, Shishaldin was \"throwing fire and glowing\" and glowing during September and early October.","StartYear":1951,"StartMonth":4,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1951,"EndMonth":10,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":316,"Name":"Aniakchak 1951/6","Description":"   Reeder (1987) reported that Pilot Everett Skinner observed \"an extensive eruption cloud\" from Aniakchak on June 25, 1951.  This event is generally thought to be a resuspension of ash particles rather than a volcanic eruption.","StartYear":1951,"StartMonth":6,"StartDay":25,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1951,"EndMonth":6,"EndDay":25,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":275,"Name":"Westdahl 1951/7","Description":"   From Miller and others (1998): \"Based on recent observations from aircraft, however, Pogromni does not appear to have been active in historical time.  The eruptions should probably be assigned to Westdahl.\"\r\n   Jones (1952) reports that an officer of one of the TAKL ships reported that Pogromni volcano was not active on July 2, but it was smoking on July 5 to 7.","StartYear":1951,"StartMonth":7,"StartDay":5,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1951,"EndMonth":7,"EndDay":7,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Westdahl","ParentVolcano":"Westdahl","VolcanoID":"ak322","ParentVolcanoID":"ak322"},{"ID":489,"Name":"Trident 1951/7","Description":"   From Decker (1963): \"Al Kropf, pilot with the U.S. Fish and Wildlife Service, reports ash eruptions from a fissure on the side of Mt. Trident were taking place during his aerial patrols to the Shelikof Straits in 1951.  The aerial photographs (137 + 138 V10 VP-61 7-7-51 2252 21,200 NAE) taken on July 7, 1951, clearly show a radial fissure over 3000 feet long extending down the southwest flank of Mt. Trident.  Fume was present from one vent along the fracture centered in a 2000 foot diameter patch of ash darker than the 1912 Katmai ash.  These aerial photographs also show that no lava flows had taken place prior to July, 1951.\"   However, Hildreth (1983) disbelieves this account: \"Published compilations notwithstanding, there are no credible reports of historic eruptions in the Katmai group except at Novarupta in 1912 and at Trident in 1953 - 1968.\"  The ash could be remobilized tephra from previous eruptions in the Katmai area.","StartYear":1951,"StartMonth":7,"StartDay":7,"StartTime":null,"StartQualifier":7,"StartQualifierUnit":"Days","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Trident","ParentVolcano":"Trident","VolcanoID":"ak288","ParentVolcanoID":"ak288"},{"ID":466,"Name":"Martin 1951/7","Description":"   From Muller and others (1954): \"In recent years Mount Martin, a 6050-foot peak 11 miles southwest of Mount Trident, has been one of the steadiest performers in this part of the Aleutian Range.  Because of Mount Martin's location, some of its activity has been incorrectly attributed to its larger neighbor to the northeast, Mount Mageik.  Probably both the ashfall at Kukak Bay on July 22, 1951, and the eruptions reported as occurring simultaneously with Mount Trident's activity in February 1953, came from Mount Martin.\"\r\n   Miller and others (1998), however, doubt the validity of this eruption, stating that \"all reports of eruption or ash emission are probably spurious, reflecting only the persistent and conspicuous steam plume.  Steam emission is normally vigorous and continuous from the summit vent of Mount Martin with plumes occasionally rising 600 m above the vent and extending downwind for 20 km.\"","StartYear":1951,"StartMonth":7,"StartDay":22,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Martin","ParentVolcano":"Martin","VolcanoID":"ak189","ParentVolcanoID":"ak189"},{"ID":480,"Name":"Mageik 1951/7","Description":"   Muller and others (1954) state that the ash that fell on Kukak Bay on July 22, 1951, was probably from an eruption of Mount Martin, rather than Mount Mageik.  \r\n   However, Sumner (1952), who flew over Mount Mageik in June, 1951, does not mention any eruptive activity at Mageik.  Fierstein and Hildreth (2001) state that there was no eruption in 1951, and that any ashfall witnessed was simply remobilized ash from the 1912 eruption of Novarupta: \"Not a single one of the 20th century tephra eruptions of Mageik listed in 'Volcanoes of the World' (Simkin and Siebert, 1994) seems plausible.  Configuration of the crater has not changed since it was first photographed in 1923; there are no juvenile ejecta in the crater or around its rim (except a scattering of 1912 pumice lapilli); and the only late Holocene fall deposits on or near the lower flanks of Mageik are the Novarupta pumice falls of 1912 and the black Trident ash of 1953-74.\"","StartYear":1951,"StartMonth":7,"StartDay":22,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mageik","ParentVolcano":"Mageik","VolcanoID":"ak187","ParentVolcanoID":"ak187"},{"ID":501,"Name":"Katmai 1951/8","Description":"   From Jones (1952): \"On August 9 [1951], A.E. Jones saw the volcanoes from Pavlof to Douglas, and, although an ash fall near Katmai had been reported a few days before, he could see no signs of activity.\"  Hildreth (1983) states: \"Published compilations notwithstanding, there are no credible reports of historic eruptions in the Katmai group except at Novarupta in 1912 and at Trident in 1953 - 1968.\"","StartYear":1951,"StartMonth":8,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Katmai","ParentVolcano":"Katmai","VolcanoID":"ak147","ParentVolcanoID":"ak147"},{"ID":122,"Name":"Bogoslof 1951/9","Description":"   Jones (1952) describes this possible eruption as follows: \"Lieutenant Sinclair, of the ship TAKL 36, reported running through muddy water for 2 miles 3.7 miles off the coast of Bogoslof on September 21 [1951].  G.R. MacCarthy visited Bogoslof early in November and reported that there were no signs of activity for many years past.\"  This muddy water could be evidence of an eruption or submarine landslide at Bogoslof (Byers, 1959).","StartYear":1951,"StartMonth":9,"StartDay":21,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Bogoslof","ParentVolcano":"Bogoslof","VolcanoID":"ak29","ParentVolcanoID":"ak29"},{"ID":207,"Name":"Pavlof 1951/10","Description":"   Jones (1952) reported that in October of 1951 \"fresh ash was reported on the north slope\" and on November 13, 1951 there was a \"sudden small explosion\" and it \"continued active through the rest of the winter.\"\r\n   The Anchorage Daily News (1953) reported that Pavlof \"erupted with a fiery and spectacular fury\" in 1951.","StartYear":1951,"StartMonth":10,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1952,"EndMonth":2,"EndDay":null,"EndTime":null,"EndQualifier":2,"EndQualifierUnit":"Months","Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":249,"Name":"Akutan 1951/10","Description":"   Jones (1951) reported minor ash showers and fume emissions from Akutan in 1951, and he also (Jones, 1952) reported that during October 1951, the lower slopes of Akutan showed fresh black ash on top of the snow, but the summit of the volcano was concealed in cloud.","StartYear":1951,"StartMonth":10,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":69,"Name":"Korovin 1951/11","Description":"   Jones (1952) reports steaming from Korovin in November 1951.  This steam may be from normal fumarolic and hydrothermal activity at Korovin, and not part of a volcanic eruption.","StartYear":1951,"StartMonth":11,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Korovin","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak171","ParentVolcanoID":"ak17"},{"ID":291,"Name":"Cleveland 1951/11","Description":"   From Jones, (1952): \"G.R. MacCarthy reported a large, dense column of mingled dark fume and steam at Cleveland volcano on November 1 [1951].  The volcano was also reported smoking in December.\"","StartYear":1951,"StartMonth":11,"StartDay":1,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1951,"EndMonth":12,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":147,"Name":"Makushin 1951/12","Description":"   From Jones (1952): \"December 20, 1951 - A high column of white smoke (steam) rose above the summit of Makushin volcano, Unalaska Island, and the snow on the volcano was gray with ash.\"","StartYear":1951,"StartMonth":12,"StartDay":20,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":148,"Name":"Makushin 1952","Description":"   Powers (1958) reports Makushin was smoking in 1952.","StartYear":1952,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":427,"Name":"Iliamna 1952","Description":"   Powers (1958) lists \"smoke\" at Iliamna in 1952.  This is likely just steam from Iliamna's prominent and long-lived fumaroles, and not a volcanic eruption.","StartYear":1952,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":42,"Name":"Gareloi 1952/1","Description":"   Jones (1952) reports that on January 17th, 1952, \"a column of grayish-brown fume was rising from the crater on the summit of Gareloi volcano.\"","StartYear":1952,"StartMonth":1,"StartDay":17,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Gareloi","ParentVolcano":"Gareloi","VolcanoID":"ak106","ParentVolcanoID":"ak106"},{"ID":250,"Name":"Akutan 1953","Description":"   Powers (1958) reports an ash eruption at Akutan from 1948-1953.  Other compilers state only an eruption or possible eruption at Akutan in 1953.","StartYear":1953,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":505,"Name":"Novarupta 1953","Description":"   Keller and Reiser (1959) reported Novarupta steaming during 1953 and 1954.  This type of activity does not represent a volcanic eruption.","StartYear":1953,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1954,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Novarupta","ParentVolcano":"Novarupta","VolcanoID":"ak203","ParentVolcanoID":"ak203"},{"ID":490,"Name":"Trident 1953/2","Description":"   Mount Trident erupted intermittently from 1953-1974.  Some (Miller and others, 1998) consider this period as one eruptive event while others (Simkin and Siebert, 1994) break it up into discrete, separate eruptions.  Detailed timelines and observations of the eruptive activity at Mt. Trident during this time can be found in Decker, 1963; Ray, 1967, and Ward and Matumoto, 1967.  Synder (1954) gives extremely detailed information about events in 1953 and 1954.\r\n   Hildreth and others (2003) summarize the eruption as follows: \"Beginning in February 1953, a new andesite-dacite edifice (0.7-cubic km volume) was built at the southwestern margin of the Trident group [see unit tsw, fig. 3, in original text]. Though sometimes referred to informally as 'New Trident,' we have called it Southwest Trident (Hildreth and others, 2000), in anticipation of the day it ceases to be Trident's youngest component. During 2 decades of sporadic explosive activity (Vulcanian type and effusive), a new composite cone covering about 3-square km area was constructed of block-and-ash deposits, scoria, agglutinate, stubby lava lobes, and the intercalated proximal parts of the main lava flows that spread as an apron beyond the cone. The cone grew to an elevation of 4,970 ft (1,515 m) (Global Positioning System measurement by Coombs and others, 2000) on the former site of a 100-m-wide fumarolic pit at about 3,840-ft (1,170 m) elevation on the steep southwest flank of Trident I. Although relief on its south slope exceeds 700 m [see fig. 13 in original text], the new cone thus has a central thickness of only 345 m and a volume of about 0.3 cubic km. At successive stages of cone construction, four blocky leveed lava flows effused from its central vent, in 1953, 1957, and 1958 and during the winter of 1959-60 [see figs. 3, 13 in original text]. Each flow is 25 to 60 m thick and 2.5 to 4 km long, and altogether they add about 0.35 cubic km to the eruptive volume. The cone's summit is today marked by a shallow crater, 350 m wide [see fig. 14 in original text], that was the site of several small ephemeral plugs, which were emplaced after the final lava flow and were repeatedly destroyed by intermittent explosive activity (1960-74). \r\n   \"Black, rapidly expanding, cauliflower ash clouds rose 6 to 9 km at least 10 times between 1953 and 1974 and possibly 12 km once or twice. Several times during the first month of activity, light ashfall dusted areas as far as 30 to 50 km from the vent, in all sectors. By far the most voluminous fallout appears to have resulted from the initial outburst of February 15, 1953 (Snyder, 1954), which may have been sub-Plinian. A single nongraded scoria-fall layer (5-17 cm thick) deposited during that event is preserved at a few protected sites as far away as Mount Katmai and upper Knife Creek. Sieve data for bulk samples of this layer yield median and maximum particle sizes, respectively, of 6.5 and 100 mm in the saddle 1 km north of the vent, and 2.1 and 20 mm in the saddle 7 km northeast of the vent - between the twin western summits of Mount Katmai. Thin sheets of finer ash that fell during the many smaller subsequent outbursts have been almost entirely removed or reworked by wind and runoff. Abundant ballistic blocks, variously breadcrusted, densely vitrophyric, or scoriaceous, that are scattered as far as 3 km from vent are products of many discrete explosive episodes (none of which were closely observed) distributed over 2 decades. Liberal estimates of total fallout volume yield no more than 0.05 cubic km, contributing less than 10 percent of the total eruptive volume of 0.7+/-0.1 cubic km. \r\n   \"The period of most frequent observation was from February to September 1953, principally by military reconnaissance aircraft during the early months (Snyder, 1954) and by a U.S. Geological Survey (USGS) party that camped at Knife Creek during the summer (Muller and others, 1954). When the vent was first seen through the cloud layer on the fourth day of activity (Feb. 18, 1953), an effusive lava flow (then already 250 m wide) was upwelling centrally and spreading radially (fig. 15A). Although a fumarolic pit, as much as 40 m deep, was conspicuous at the impending ventsite on aerial photographs taken in 1951 (and had probably been further excavated by the explosive outburst of Feb. 15), any such crater was soon filled and buried by the effusive lava [see fig. 15A in original text], which continued to be extruded and spread slowly throughout the seven months of intermittent observation in 1953. At various times, lava lobes emerged laterally through the chilled carapace at the foot of the pile, or the pile itself 'expanded like a balloon' and extruded lobes by overflow from the vent, or small slumps and slide masses detached from the steep flow margins (Snyder, 1954). By June 1953, the main southerly tongue of lava, ultimately 4.2 km long, had advanced only 1,250 m from the vent. Snyder (1954) estimated the volume of fallout and lava produced by June 17, 1953, at 0.23 to 0.3 cubic km, about a third of the eventual output. During the summer, steady steaming and continued spreading of the lava was punctuated sporadically by steam bursts [see fig. 15B in original text] or occasional 'smoke columns' that rose 1 to 3 km and dusted various proximal sectors with minor additional ashfall (Muller and others, 1954). \r\n   \"Observations after September 1953 were sporadic and few. A general chronology of major events was compiled by Decker (1963) and augmented by Ray (1967), largely from intermittent National Park Service reports. The 1953 lava flow may not have attained its final dimensions [see fig. 3 in original text] until early 1954 or later. Apparently, no observations were made during eruption and outflow of the lava flows of 1957, 1958, and 1959-60 [see fig. 3 in original text], merely aerial snapshots taken in the summer seasons after the emplacement of each flow. The time of emplacement of the lava flow attributed to the winter of 1959-60 is the least well known, because no photographs are known to have been taken between September 1958 and August 1960. The 1958 lava flow partly overran the 1953 flow [see fig. 3 in original text] and impounded a small lake on upper Mageik Creek that soon filled in with pumiceous alluvium, becoming a mudflat (Ferruginous Flat) now marked by numerous iron-precipitating warm springs.\r\n   \"Growth of the fragmental cone [see figs. 13, 14 in original text] began only after much or all of the 1953 lava flow [see fig. 15 in original text] had been emplaced. The cone accumulated progressively during the later 1950s, as shown by emergence of the successive lava flows at different levels of the fragmental edifice. National Park Service photographs show that the cone had attained nearly its full height by 1960, although explosive showers of blocks continued to augment the cone until 1974. In addition to the four main lava flows, cone construction included emplacement of several stubby lava lobes limited to its proximal southwest slope [see fig. 3 in original text]. The southeast side of the cone completely buried a 1-km-square-area cirque glacier, with no recognized effects on eruptive behavior or edifice structure, although enhanced steaming may have contributed to the stronger fumarolic emission and alteration on that side of the cone [see fig. 14 in original text]. Explosive ejections of tephra, some involving blowout of plugs and at least one spine, took place from 1960 to 1974, but volumetrically significant eruptions were over by 1963. Numerous sulfurous fumaroles, superheated in the 1960s but below and at the boiling point today, persist on the upper parts of the cone [see fig. 14 in original text]. Dark-gray bouldery debris flows reworked from the pyroclastic deposits have built a proximal fan and thin distal sheets (1-4 m thick) that cap stream terraces for 3 km downstream along Mageik Creek. Some debris flows resulted from the initial February 1953 fallout over snow, and others from avalanching of rubble from the steep slopes of the cone.\"","StartYear":1953,"StartMonth":2,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1974,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Trident","ParentVolcano":"Trident","VolcanoID":"ak288","ParentVolcanoID":"ak288"},{"ID":467,"Name":"Martin 1953/2","Description":"   Muller and others (1954) state that they believe the \"eruptions reported as occurring simultaneously with Mount Trident's activity in February 1953\" came from Mt. Martin, and also note that \"During the second week of July [1953] Mount Martin was observed to be steaming steadily and with moderate vigor, although its plume was less conspicuous than that of Trident.  During this interval, only quiet steaming occurred at the crater near the crest of Mount Mageik.\"\r\n   However, Miller and others (1998) discount this eruption report, saying \"all reports of eruption or ash emission are probably spurious, reflecting only the persistent and conspicuous steam plume.  Steam emission is normally vigorous and continuous from the summit vent of Mount Martin with plumes occasionally rising 600 m above the vent and extending downwind for 20 km.\"","StartYear":1953,"StartMonth":2,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Martin","ParentVolcano":"Martin","VolcanoID":"ak189","ParentVolcanoID":"ak189"},{"ID":481,"Name":"Mageik 1953/2","Description":"   MacDonald (1953) reports that on February 21, 1953, the Kodiak Mirror reported that Mount Mageik had erupted.  Addiontal reports of activity at Mageik (\"steaming and smoking badly\") are found in the July 13 and 14 editions of the Anchorage Daily News.  Fierstein and Hildreth (2001) doubt the validity of these reports, stating: \"Not a single one of the 20th century tephra eruptions of Mageik listed in Simkin and Siebert's (1994) \"Volcanoes of the World\" seems plausible.  Configuration of the crater has not changed since it was first photographed in 1923; there are no juvenile ejecta in the crater or around its rim (except a scattering of 1912 pumice clasts from Novarupta); and the only late Holocene fall deposits on the or near the lower flanks of Mageik are the Novarupta pumice falls of 1912 and the black Trident ash of 1953.\"  Many other accounts report that Mount Mageik was steaming during 1953 (MacDonald, 1953; Military observers, 1953; Muller and others, 1954; Snyder, 1954).  Such steam does not constitute a volcanic eruption.","StartYear":1953,"StartMonth":2,"StartDay":21,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mageik","ParentVolcano":"Mageik","VolcanoID":"ak187","ParentVolcanoID":"ak187"},{"ID":428,"Name":"Iliamna 1953/3","Description":"   Snyder (1954) reports that \"The Anchorage Daily News of March 3 quotes a Mrs. William Tauscher of Anchor Point (Kenai Peninsula) as saying that Iliamna Volcano 'poured forth with a huge mushroom-shaped billow of inky black smoke at 7:30 a.m. Sunday (March 1).'  Two distinct sources of eruption are claimed to have been sighted, one on top and one off to the side of the mountain.  Lt. James Ingram USN flying about 50-75 miles south-southeast of the Iliamna area on March 3 gives a partial confirmation of this story.  He sighted a cloud column rising from the mountain but at that distance could not discern whether it was smoke or steam.  The writer visited the Iliamna area aboard naval aircraft on March 5 and 6.  On these dates only a small fumarole near the top and on the east side of Iliamna was active, sending up a column of steam several hundred feet high.  No ash was visible on the glaciers blanketing the mountain.\"","StartYear":1953,"StartMonth":3,"StartDay":1,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":457,"Name":"Cone A 1953/3","Description":"   From Snyder (1953): \"On March 2 [1953] Richard McDonald, U.S. Geological Survey seismologist stationed at Adak, rode a Navy plane from Kodiak to Adak and back.  He reported steam rising from Pavlof, Shishaldin, Makushin, and a small cone within Okmok Caldera on this day.\"","StartYear":1953,"StartMonth":3,"StartDay":2,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cone A","ParentVolcano":"Okmok","VolcanoID":"ak56","ParentVolcanoID":"ak206"},{"ID":56,"Name":"Great Sitkin 1953/5","Description":"   From MacDonald (1953): \"[O]n May 11, 1953, the Coast and Geodetic Survey ship Pioneer observed a spectacular column of steam rising an estimated 5,000 feet above Great Sitkin volcano, in the Aleutian Island.  The steam column lasted about an hour.  An earthquake felt at Adak on May 12, with an intensity of 5 on the modified Mercalli scale, had its epicenter on a line passing through Great Sitkin.  On the afternoon of May 14 a steam cloud was seen to rise about 4,000 feet above the crater rim of Great Sitkin, and during the evening another earthquake occurred, slightly less severe than that of May 12, with its epicenter on the same line.  Both quakes apparently were more severe on Great Sitkin than on Adak.  When next observed, on May 19, the steaming of Great Sitkin Volcano was much diminished but still greater than normal.  Subsequent observations on May 23, June 5, and June 7 showed only weak emission of steam.  No ash eruption was observed during the period from May 11 to June 7, nor did the form of the basalt dome in the crater of Great Sitkin change appreciably.\"\r\n   Simkin and Siebert (1994) call this eruption a discredited eruption due to the fact that apparently no ash was emitted.\r\n   In addition, R.W. Laughead (military observer) reported a \"thick steam column with some smoke grey in color\" on 29 July 1953.","StartYear":1953,"StartMonth":5,"StartDay":11,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1953,"EndMonth":5,"EndDay":14,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":70,"Name":"Korovin 1953/6","Description":"   The following observations of Korovin are compiled from individual observation sheets filled out by members of the public and U.S. military.\r\n19 June 1953: \"Steam, slightly darker than low lying fog was spilling over northwestern lip - wind prevented formation of column.  Snow on eastern face appeared to have been darkened by cinders of soot to almost black.  It was not bare rock showing.  It was a darkened snow coverage.\" -- observed by USCG ship Pioneer\r\n25 June 1953: \"All snow covering mountain darkened by thin coating ash in sharp contrast with brilliantly shining snow on hills to south; steam seen emitted from fumarole on N crater rim to about 100 feet; no steam being emitted from crater proper (or at least that portion visible from plane). -- R R McDonald\r\n13 February 1954: \"White smoke rising to height of approximately 50 feet. No lava flow visible.\" -- J.:. Thurman, LCDR, USNR\r\n18 March 1954: \"Steaming good.\" -- Report of Reeve's Aleutian Airways pilot\r\n25 March 1954: \"Column of steam rising 100 to 150 feet above peak, no dispersal evident.  Closer view showed no signs of activity in form of smoke or fire.\" -- John Mays, Lt, USNR\r\n5 April 1954: \"Steam and smoke rising one thousand feet from floor of crater on NE corner.  No lava or fire visible.\" -- E.L Burdick\r\n14 May 1954: \"Steam with strong sulfur odors rising from northern edge inside the crater, about 300' down from the rim. Rises about 1000'.\" -- R.L. Kopps\r\n15 June 1954: \"Some steam from center of volcano - 100-200 ft. high before dissipating.\" -- D.C. Curran Lt.\r\n17 June 1954: \"No apparent activity.\" -- C.R. Pendell LTJG\r\n15 July 1954: \"Faint vapor fresh snow (on cone dirtied by this showering of ash)\" -- Austin E. Jones\r\n14 September 1954: \"No smoke or other visible signs of activity.\" -- E.D. Jezek","StartYear":1953,"StartMonth":6,"StartDay":null,"StartTime":null,"StartQualifier":2,"StartQualifierUnit":"Months","EndYear":1954,"EndMonth":7,"EndDay":null,"EndTime":null,"EndQualifier":1,"EndQualifierUnit":"Months","Volcano":"Korovin","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak171","ParentVolcanoID":"ak17"},{"ID":292,"Name":"Cleveland 1953/6","Description":"   From Miller and others (1998): \"On June 25, 1953, a military observer reported dark ash on the snow around the vent of Mt. Cleveland (report on file at Geophysical Institution, University of Alaska, Fairbanks).\"\r\n   Military observers also reported steam on December 19, 1953.","StartYear":1953,"StartMonth":6,"StartDay":25,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":459,"Name":"Griggs 1953/7","Description":"   From Muller and others (1954): \"During July [1953] mild fumarolic activity was reported near the crest of Knife Peak [Griggs] by Lt. James Mulkern, pilot with a topographic survey unit of the Army Corps of Engineers.  This peak has no history of more vigorous activity.\"  This activity does not constitute a volcanic eruption.","StartYear":1953,"StartMonth":7,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Griggs","ParentVolcano":"Griggs","VolcanoID":"ak112","ParentVolcanoID":"ak112"},{"ID":311,"Name":"Crater Peak 1953/7","Description":"   Initial newspaper accounts of this eruption exclaim \"City blacked out by 3 volcanoes!\" in large bold type, but in reality, only one volcano, Mt. Spurr, was actually erupting.  \"Mt. Torbert,\" as well as the third \"unnamed volcano\" are not volcanic, and were not erupting.  Precursory activity to this eruption may have been observed in mid-May, 1953, when Northern Consolidated Airline pilots reported increased steaming from the summit of Spurr (Unknown, 1953; Fairbanks News-Miner, May 21, 1953).\r\n   From Waythomas and Nye (2002): \"The first known historical eruption of Crater Peak occurred at about 5 a.m. on July 9, 1953 (Juhle and Coulter, 1955; Miller and others, 1998).  For at least 30 years prior to the 1953 eruption, plumes of whitish steam commonly were observed rising from the summit of Crater Peak;\" [Note:  Although Waythomas and Nye report steaming from Crater Peak, newspaper accounts and pilot observations of the area state that the steaming came from the summit of Spurr.]  Waythomas and Nye continue: \"pilots reported an increase in the vigor of steaming in late spring 1953 (Juhle and Coulter, 1955).  At the time of the 1953 eruption, instruments to monitor the seismic activity were not available.  The 1953 eruption was a single explosive burst lasting about one hour, and it generated an ash cloud that rose more than 10,000 meters above sea level (Juhle and Coulter, 1955).  Ash fall occurred east of the volcano [see fig. 6 in original text] and approximately 6 millimeters of ash accumulated in Anchorage.  A light dusting of ash was reported as far away as Valdez and as close as 48 km to Cordova (Juhle and Coulter, 1955).  Pyroclastic flows mixed with snow and ice high on the crater rim and combined with heavy rainfall to produce lahars that inundated tributaries to the Chakachatna River on the south flank of Crater Peak.  The lahars flowed into the Chakachatna River and formed a substantial debris dam across the river (Juhle and Coulter, 1955; Meyer and Trabant, 1995).\"\r\n   Wilcox (1959) gives detailed eruption descriptions:  \"On July 10 at 5:00 am the vent was only steaming.  At 3:30 pm an especially strong surge of ash-laden steam rose to 20,000 feet.\"  Juhle and Coulter (1955) state that the eruption continued with steam and small bursts of ash from July 11 to July 16, 1953.\r\n   Ash began to fall in Anchorage at about noon on July 9, 1953, and darkened the sky from 1 p.m. until about 3 p.m. (Wilcox, 1953; Juhle and Coulter, 1955; Wilcox, 1959).  This ashfall was disruptive to traffic at Elmendorf Air Force Base and Anchorage International Airport.  Three jet aircraft that were sent to investigate the ash plume returned with sandblasted wing leading edges, windshields, side panels, and front portions of their canopies.  Elmendorf Air Force Base was closed to air traffic from July 9 -17 due to the eruption (Kienle, 1994).  See Wilcox (1959) for detailed pilot descriptions of the ash cloud.","StartYear":1953,"StartMonth":7,"StartDay":9,"StartTime":"05:05:00","StartQualifier":null,"StartQualifierUnit":"","EndYear":1953,"EndMonth":7,"EndDay":16,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Crater Peak","ParentVolcano":"Spurr","VolcanoID":"ak70","ParentVolcanoID":"ak260"},{"ID":455,"Name":"Kukak 1953/7","Description":"   From Siebert and Simkin (2002-, accessed March 23, 2007): \"A 1953 explosive \"eruption\" was single large puff of steam followed by steaming from caverns in Hook Glacier (Muller and others, 1954).\"\r\n      Muller and others (1954) reads: \"Kukak Volcano, which had been steaming steadily, emitted a single large puff of steam on July 22 according to the captain of the Fish and Wildlife Service's ship Dennis Wynn.  At the end of July considerable steam was escaping from large caverns in Hook Glacier on the flank of Kukak Volcano, possibly indicating the position of newly activated vents.\"","StartYear":1953,"StartMonth":7,"StartDay":22,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kukak","ParentVolcano":"Kukak","VolcanoID":"ak174","ParentVolcanoID":"ak174"},{"ID":373,"Name":"Shishaldin 1953/10","Description":"   Snyder (1954): \"On March 2 [1953] Richard McDonald, U.S. Geological Survey seismologist stationed at Adak, rode a Navy plane from Kodiak to Adak and back.  He reported steam rising from Pavlof, Shishaldin, Makushin, and a small cone within Okmok Caldera on this day.\"  Powers (1953; 1958) reports an ash eruption at Shishaldin in October, 1953.","StartYear":1953,"StartMonth":10,"StartDay":3,"StartTime":null,"StartQualifier":4,"StartQualifierUnit":"Days","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":208,"Name":"Pavlof 1953/11","Description":"   Powers (1953) reports \"glowing\" from Pavlof on November 25, seen \"by the personnel of the Penguin, sailing from the Pribilof Islands.\r\n   From the Volcano Observations folder on file at the University of Alaska Geophysical Institute: \"1953 Dec 26: Small light grey smoke column from peak rising 200 feet, dispersing to north. No odor detected at 2 miles distance. Sides of mountain were covered with what appeared to be ashes halfway down the slope on the southeast side. The other side couldn't be observed that day.\"  Selected Pavlof volcano observation forms on file in this folder for the year 1953 record the following observations:\r\n   - January 4: \"dark smoke\" being emitted, fresh ash on snow visible, and a \"red cone was visible at the core\"\r\n   - January 8: \"steady puffs of smoke and steam intermingled with rocks, flames, and lava were seen blowing from at least one hole on the NNE side, the rocks shooting as high as 200 feet, the lava trickling down to 2000 feet * * * The red glow was visible as far as Rocky Point, some 275 miles northeast.\"\r\n   -January 9: \"much smoke seen drifting eastward and forming a layer at 8000 feet.  Black smoke with red tinge was boiling actively from area just below area whence lava is flowing\"\r\n   -January 12: \"Belching smoke * * * ash on southwest side as well as across northern face * * * Appears to be a lava flow along NW side\"\r\n   -January 14: \"Black smoke rising from hole on north side of the summit to height of approximately 500 feet.  Hole 15 feet across and glowing dull red.\"\r\n   -January 16 - March 1: smoke rising to low levels\r\n   -March 7: \"Dark cloud\" up to 14,000 feet.\r\n   -March12 - April 2: Grey to black smoke\r\n   -April 21: \"Throwing out red hot bombs to northwest side as seen from FWS Penguin in the passage from the Shumagin Islands past Pavlof Bay to Dutch Harbor - visible all through the night - throwing out showers of bombs\"\r\n   -May 3 - Oct 31 (date of last Pavlof observation for 1954) - continuing intermittent \"black\" or \"grey\" smoke and ash.\r\n   Pavlof observations for 1955 continue in July - observations on July 4 and 16 record \"black smoke\" and ashes to 200 feet.","StartYear":1953,"StartMonth":11,"StartDay":25,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1954,"EndMonth":8,"EndDay":null,"EndTime":null,"EndQualifier":4,"EndQualifierUnit":"Months","Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":149,"Name":"Makushin 1953/12","Description":"   Powers (1953) reports steaming from Makushin in December, 1953.  Barnett (1963) writes that he climbed Makushin either in the summer of 1953 or 1954 (article is unclear) and witnessed steaming, \"snow grey from wind-carried ash thrown from the active crater,\" a sulfur smell, and boiling mud pots.  This activity probably does not constitute a volcanic eruption.   Snyder (1954) writes: \"On March 2 [1953] Richard McDonald, U.S. Geological Survey seismologist stationed at Adak, rode a Navy plane from Kodiak to Adak and back.  He reported steam rising from Pavlof, Shishaldin, Makushin, and a small cone within Okmok Caldera on this day.\"","StartYear":1953,"StartMonth":12,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":294,"Name":"Cleveland 1954","Description":"   Military observers reported smoke and steam at various times throughout 1954, including steam on January 11, light smoke on February 13, steam and gray smoke on April 5, heavy steam on June 30, light gray smoke on July 2, ash on July 15, gray-white smoke on September 4, and white steam on December 9.","StartYear":1954,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":460,"Name":"Griggs 1954","Description":"   Keller and Reiser (1959) reported Mt. Griggs \"steaming\" in 1954.  This activity does not constitute a volcanic eruption.","StartYear":1954,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Griggs","ParentVolcano":"Griggs","VolcanoID":"ak112","ParentVolcanoID":"ak112"},{"ID":482,"Name":"Mageik 1954","Description":"   Mount Mageik steamed intermittently during 1954.  Such steaming does not constitute a volcanic eruption.  A summary of reports given by military observers (on file at the University of Alaska Fairbanks Geophysical Institute) is as follows: \r\n   -20 Jan: steam and light grey smoke bubbling actively from a small peak crater.  There is some likelihood of fire within this crater.  This was originally thought to be Mt. Cerberus but subsequent observations establish this to be Mageik which had at an earlier date been reported with a single whisp of steam.  \r\n   -16 February 1954: steam rising from hole in peak to be blown eastward down slope.  No smoke, no odor.  \r\n   -25 June: Quantities of white smoke and steam.  Molten sulphur pool in crater.  Smoke rising approx. 1000ft.  Dispersing to the west.  5 August: Light steam rising 500 feet.  \r\n   -1 Oct: Small amount of steam coming out of two different vents: one at tip of peak with the other on east shoulder of peak about 500' from top.","StartYear":1954,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mageik","ParentVolcano":"Mageik","VolcanoID":"ak187","ParentVolcanoID":"ak187"},{"ID":374,"Name":"Shishaldin 1954/1","Description":"   Military pilots documented many observations of Shishaldin Volcano during 1954.  A summary of their observations follows: Jan. 4: Steam rising from peak crater only, to 100ft above peak, dispersing to N. Several burned-off streaks along slopes but no evidence of recent ash or lava activity. Three small orifices in crater showed fire from close aerial range; Jan. 5: Small light grey smoke rose from peak, dispersing to SE. No visible activity other than this single small column; Jan. 8: Steam or light smoke rising from peak only. Usual evidence of hot ashes along N slope where snow is darkened. Wind blew the smoke straight off the peak; Jan. 14: Steam or light smoke filling entire crater rising 25-50 ft in the air. Single spire of steam or light smoke extended several miles to the NW from the peak; Jan. 16: Continuous flow of smoke coming from summit towards N. No lava. Smoke clung to and drifted down N side of mtn. Smoke visible from as far away as Pavlof; Feb. 12: Very small steam coming from summit. Ash on NW side. No lava; Feb. 22: Small steam and smoke rising to SE, ash covered SE side. No evidence of lava; Apr. 5: Heavy steam from crater only; May 21: Steam rising 100 ft from central crater; June 3: Some steam coming out of top of volcano crater;  July 16: Heavy brown-black smoke rising to 13,000 ft. Lava running down slope. Smoke rising to 13,000 ft from base on N side; Aug. 14: Considerable steam coming out of the top of the crater. Steam drawn out about a mile horizontally before dissipating to the north; Oct. 31: Steady steam from peak","StartYear":1954,"StartMonth":1,"StartDay":4,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1954,"EndMonth":10,"EndDay":31,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":337,"Name":"Shrub 1955","Description":"   Nichols and Yehle (1961) provide a description of Shrub mud volcano as they saw it during the summers of 1955 and 1956.  \"A vegetation-bare basin or crater about 120 feet in diameter and floored by clayey silt is present on the southwest side of the cone about thirty-five feet below the crest.  In 1955 this basin had seven pools, two to eighteen inches in diameter, from which gas and silt-laden water were discharged.  Only a trickle of water from the pools drained across the basin and down the steep-sided cone.  The flow of water must have been considerably greater in the past as indicated by the presence of two barren drainageways on the south and west sides of the cone where non-salt-tolerant plants have been killed. \r\n   \"In 1956 only four pools, one to two inches in diameter, remained and both gas and water emanations were sharply reduced in volume.  There was no surface drainage away from the pools.  The surface of this and other cones has been much trampled by moose and, possibly, caribou which graze in the area and drink the salty water.  These animals, by stepping in or near the vents may cause them to be temporarily, or perhaps even permanently clogged.  This may result either in a shift in gas outlets or, in the case of weak activity, complete cessation of discharge.\"","StartYear":1955,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1956,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Shrub","ParentVolcano":"Klawasi Group","VolcanoID":"ak253","ParentVolcanoID":"ak163"},{"ID":375,"Name":"Shishaldin 1955/7","Description":"   From Anchorage Daily News (1955): \"Heavy volcanic ash today is blanketing the Cold Bay area, near the tip of the Alaska Peninsula.  \r\n   \"Ashes from 'Old Smoking Moses,' Mt. Shishaldin, the active volcano some fifty miles southwest of Cold Bay on Unimak Island.  Shishaldin has been in a state of eruption for the past two weeks.\r\n   \"Weather reports from Cold Bay advise that the ash fall is from Shishaldin rather than Mt. Pavlof which is located only 25 to 30 miles northeast from Cold Bay.  Winds in the area have been recorded as being from the southwest instead of the northeast.\r\n   \"The report was confirmed by the Anchorage weather bureau today.\r\n   \"Last Sunday, a river of flaming lava poured down the steep slopes of 9,979-foot Shishaldin in what was termed a major eruption.\r\n   \"Coast Guard officials at Cape Sarichef have reported Shishaldin in a state of 'intermittent eruption.'\r\n   \"Fire and huge plumes of smoke were observed to belch from the cone all day Sunday.\"\r\n   A July 22, 1955 UP article reported: \"Mount Shishaldin is continuing to blow its top following the largest eruption in the memory of the island's residents.\r\n   The entire top of the mountain 'seems to have exploded,' according to a report received today from the Cape Sarichef coast guard station * * *.  Huge blots of lighting flashed over the volcano's fiery cone following the latest eruption, causing radio interference in the area, a coast guard official reported.\r\n   \"Mount Shishaldin's top has been partially blown away, the commanding officer at Cape Sarichef reported.  A new fissure has been ripped into the side of the peak and it is spewing a gusher of lava for a distance of several thousand feet.\"\r\n   An Associated Press article from July 23, 1955, states that Gordon Gay, Cold Bay agent for Reeve Aleutian Airways, estimated the \"clouds of smoke, soot, and ash are rising in the air over Shishaldin to an estimated 50,000 feet.\"","StartYear":1955,"StartMonth":7,"StartDay":1,"StartTime":null,"StartQualifier":14,"StartQualifierUnit":"Days","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":318,"Name":"Veniaminof 1956/3","Description":"   From Miller and others (1998): \"Activity beginning in March 1956 culminated with ash explosions on May 19 and 23, 1956 which sent ash-rich eruption columns to approximately 6,100 m according to airline pilot reports.\"  An Anchorage Daily News article from May 21, 1956, reads as follows:\"Mount Veniaminof, an 8,200-foot volcano which as been active for the last two months, started 'spewing quite a bit of stuff' over the weekend, a Reeve Aleutian Airways pilot reported today.\r\n   \"Bill Borland, chief pilot of the airline, said today he flew over the mountain, which is about 60 miles southwest of Port Heiden, and the eruptions were the severest he had seen since the volcano became active about two months ago.\"","StartYear":1956,"StartMonth":3,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1956,"EndMonth":5,"EndDay":23,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Veniaminof","ParentVolcano":"Veniaminof","VolcanoID":"ak301","ParentVolcanoID":"ak301"},{"ID":111,"Name":"Vsevidof 1957/3","Description":"   From Miller and others (1998): \"Another phreatic eruption, possibly from the west rift, occurred in March, 1957 (Byers, 1959, p. 305, citing article in Anchorage Times of March 12, 1957).  Earthquakes were felt throughout southeast Umnak, and residents of Nikolski, the island's main village 24 km southwest of Vsevidof, reportedly observed discharge of steam and volcanic ash.  However, in a subsequent article (Anchorage Times, March 15, 1957) a pilot reportedly observed no evidence of a volcanic eruption.\"  The smoke and steam were concurrent with a large earthquake in the vicinity of Adak.","StartYear":1957,"StartMonth":3,"StartDay":11,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1957,"EndMonth":3,"EndDay":12,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Vsevidof","ParentVolcano":"Vsevidof","VolcanoID":"ak307","ParentVolcanoID":"ak307"},{"ID":209,"Name":"Pavlof 1958/5","Description":"   On August 18, 1958, R.B. Benjamin, a Reeve Aleutian co-pilot, reported that Pavlof volcano was \"more active than usual.\"  Pavlof often smokes \"but now lava is running half way down the side of the volcano\" (Anchorage Daily News, August 19, 1958).\r\n   Jacob and Hauksson (1983) report that this eruption began on May 7 and lasted until August 28, and that the lava flow moved downslope on May 14, 1958.","StartYear":1958,"StartMonth":5,"StartDay":7,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1958,"EndMonth":8,"EndDay":28,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":171,"Name":"Cone A 1958/8","Description":"   From Grey (2003): \"After a 13-year hiatus in reported eruptive activity, Okmok returned to life the evening of August 14, 1958.  Eruptive activity was first reported by sheep ranchers on northeastern Umnak, and by Reeve Aleutian Airways personnel on the island (Anchorage Daily News/Times, August 15, 16, and 19, 1958).  Reeve pilot Everett Skinner flew from Dutch Harbor to Nikolski on the SW end of Umnak Island on the morning of August 15 and observed an ash plume over Okmok reaching 5.5-6.0 km (Reeder, 1984).  On his return flight from Nikolski, Skinner flew inside the caldera to photograph and observe the eruption [see figure 4.6 in original text].  The active vent was Cone A, where two ~35 m-high lava fountains at the NE base of the cone fed a basaltic a'a lava flow extending to the NNE, eventually reaching 7.8 km in length and covering 9.36 square km [see figure 4.7 in original text] (Reeder, 1984).  According to James Bynum (Anchorage Daily News, August 29, 1958) the flow was still active on August 29, but when Skinner flew by Okmok again on September 5, he saw only steam rising from the cone and flow [see figure 4.6 in original text].  Thus, the effusion rate must have been relatively high in order for the flow to reach its full length in only two weeks.  John Reeder estimated a mean thickness of 12.8 m and a volume of 1.2 x 10^8 cubic meters, which is 6-12 times larger than the estimated volume of the 1945 flows at 1-2 x 10^7  cubic meters (Reeder, 1984).\"","StartYear":1958,"StartMonth":8,"StartDay":14,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1958,"EndMonth":9,"EndDay":2,"EndTime":null,"EndQualifier":3,"EndQualifierUnit":"Days","Volcano":"Cone A","ParentVolcano":"Okmok","VolcanoID":"ak56","ParentVolcanoID":"ak206"},{"ID":210,"Name":"Pavlof 1960","Description":"   Coats (1964) writes about Pavlof: \"Reported as quite active for about a year. Probably Strombolian phase.\" (July 1962-June 1963).\r\nJacob and Hauksson (1983) report that this eruption began around 1960 and continued until sometime in 1963, and consisted of mild ash eruptions and lava flows.\r\n   Dr. Kenneth Morin took photographs of ash and steam erupting from Pavlof on May 28, 1960.  These images are viewable on the World Wide Web at: http://www.avo.alaska.edu/volcanoes/volcact.php?volcname=Pavlof\u0026page=images\u0026eruptionid=210 .","StartYear":1960,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":1,"StartQualifierUnit":"Years","EndYear":1963,"EndMonth":6,"EndDay":null,"EndTime":null,"EndQualifier":3,"EndQualifierUnit":"Months","Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":172,"Name":"Cone A 1960/10","Description":"   From Grey (2003): \"An eruption that began in October, 1960 produced enough ash to reach Chernofski Sheep Ranch on western Unalaska Island [see figure 4.8 in original text] (Holmes, 1994).  According to John Reeder of the Alaska Division of Geological \u0026 Geophysical Surveys, who interviewed Milton Holmes, resident Chernofski rancher, 'there were times when Milton could see lava shooting above the Okmok caldera only to fall back in.  When the wind was not blowing, a red glow could be seen from the crater.  At one time, he had to wear goggles while riding range because the ash was so thick' (Reeder, 1986).  A concurrent report in the Anchorage Daily Times on October 17, 1960, states that Reeve Aleutian Airways passengers and crew 'were treated to an unexpected show of fireworks - the eruption of Tulik volcano' on October 15, involving a 'black cloud 9,500 feet into the air' and 'a 15-mile lava flow.'  The flight attendant was quoted as seeing 'red lava and chunks of rock flying through the air at the base of the volcano.'  This report is perplexing because in distinguishing between Tulik and 'Okmak Crater,' it limits the probability of misidentifying the active vent; yet as mentioned earlier [in other eruption descriptions], there is no geologic evidence to suggest an eruption from Tulik in historic times.\r\n   \"Furthermore, there are no young lava flows associated with Tulik, and the maximum length of any lava flow exposed within the caldera is 7.8 km (the 1958 flow); there is no lava flow reaching 15 mi (25 km) in length anywhere on Okmok.  Either the report was exaggerated or the number is a misprint and should have read '5-mile,' which would be reasonable.  However, despite the vigorous level of activity implied by Holmes' observations and the Times report, no lava flow has been identified associated with this activity.  It is probable that this was a brief burst of lava fountaining and the flow the Reeve passengers saw was the fresh 1958 flow.\r\n   \"There is also one report of light ash fall in the community of Unalaska, 120 km ENE of Okmok in the late fall of 1960 (Reeder, 1986).  Since neither Makushin nor Akutan volcano was erupting at the time, nor were those volcanoes immediately west of Okmok, that ash probably came from Okmok.  Simkin and Siebert (1994) list the end date for this eruption as April 15, 1961.  Based on measurements of tephra thickness within Okmok caldera by Reeder in 1980 and on western Unalaska Island by Holmes in 1961, the estimated total bulk volume of tephra from this eruption is 'greater than 1 x 10^7 cubic meters' (Reeder, 1986).  It is possible that Reeder may have included tephra from the 1958 eruption in his calculations and overestimated the 1960 eruptive volume, since no lava flow is identified associated with this event.\"\r\n   From Black (1981): \"Stanley Holmes, Unalaska, reports that when Tulik (Okmok) caldera erupted in 1960, lava ran across Crater Creek.  The temperature of the water in the creek remained above normal for a year, disrupting the salmon run (personal communication, March 22, 1978).\"","StartYear":1960,"StartMonth":10,"StartDay":15,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1961,"EndMonth":4,"EndDay":15,"EndTime":null,"EndQualifier":45,"EndQualifierUnit":"Days","Volcano":"Cone A","ParentVolcano":"Okmok","VolcanoID":"ak56","ParentVolcanoID":"ak206"},{"ID":3,"Name":"Sirius Point 1962/1","Description":"   On January 24, 1962, the north flank of Kiska volcano erupted with normal explosions, lava flow(s), and a new cinder cone, called Sirus Point, about 30 m high, was formed (Staff, 1961; Anchorage Daily News, Jan 30, 1962).  This eruption was observed from an airplane.\r\n   From the Anchorage Daily News, Jan 30, 1962: \"The Navy says a civilian pilot flying over Kiska Island in the western Rat Islands of the Aleutian chain last Saturday reported a new volcano had erupted on the island.\r\n   \"A Navy spokesman said the pilot radioed that lava could be seen flowing down into the sea from the new cone on Sirus Point, on the northern tip of the island.\r\n   \"The eruption apparently occurred sometime before the pilot, who was not identified, spotted it.\"","StartYear":1962,"StartMonth":1,"StartDay":24,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Sirius Point","ParentVolcano":"Kiska","VolcanoID":"ak254","ParentVolcanoID":"ak161"},{"ID":251,"Name":"Akutan 1962/11","Description":"   From Reeder (1988): \"Some evening during the first part of November 1962, Nick Borenin of Akutan village observed from his boat that was just outside of Akutan Harbor lava \"fire\" that was being emitted from the summit caldera of Akutan volcano.  Larry Mensoff of Akutan village said that at the time one could hear a rumbling sound from the volcano at the village, which is 12 km east of Akutan volcano.  In the next morning, the village awoke to find snow and window ledges covered with a very noticeable layer of ash.  The ash was thick enough that the village board walks had to be swept off.  The ash also got into the village water system for several days.  \r\n   \"Vince Tutiakoff of Unalaska village also reported that up to 0.0025 m of fine to coarse sand-size tephra had also fallen early the same morning at Unalaska village, which is located 47 km SW of Akutan volcano.  The event was so rare for Unalaska village that there was no school that day. \r\n   \"The exact day in the early part of November 1962 of this eruption event is unknown, but numerous residents of both Unalaska and Akutan villages clearly remembered the event when they first told me about it in 1985.\"","StartYear":1962,"StartMonth":11,"StartDay":7,"StartTime":null,"StartQualifier":7,"StartQualifierUnit":"Days","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":93,"Name":"Amukta 1963/2","Description":"   From Miller and others (1998): \"On February 13, 1963 an eruption occurred involving the central crater and one or more parasitic vents; both ash and lava were produced (Anchorage Times, February 11, 1963; Decker, 1967).  Persistent low clouds obscured the exact source of the lava, but the flow was seen to extend from the west side of the cone southwest into the sea at Traders Cove (Bulletin of Volcanic Eruptions, 1963 [Coats, R.R., 1963].\"\r\n   The text of the Anchorage Times, February 11, 1963 article is as follows: \"KODIAK - A volcano is erupting near Amukta Island on the Aleutian Chain, according to reports received at the Kodiak Naval Station.\r\n   \"A Navy plane yesterday flew near the scene and crewmen reported a mountain billowing dark gray and black smoke about 500 feet in the air.  Lava is flowing from the cone to the ocean 3,700 feet below.  Mushroom-shaped steam clouds are rising where the lava enters the ocean.\r\n   \"The volcano is erupting about every 15 mintues and was continuing its activity today, say latest reports.\r\n   \"The volcanic cloud was first spotted from the Navy ship Mizar.\"\r\n   From volcano observations on file at UAF/GI:  \"Facts reported by pilot of U.S. Navy aircraft that observed and photographed Amukta island volcano on 19 February 1963:\r\n    'We arrived over Amukta Island at an altitude of 500 feet.  The approach was made from the north end of the island.  Huge billowing clouds of steam were rising from the volcano to an altitude of 800 feet.  No lava was present on the north and east side of the island.  We continued down the west side of the island and saw a stream of red flowing lava, approximately 20-30 wide [units not given], from the obscured area of the volcano at an approximate altitude of 2,000 feet, to the southwest area of the island, where it ended.\r\n   'Hot lava was present in the sea on the southwest corner of the island where many small columns of steam were rising.  Numerous passes were made to the northwest and the southeast across the plateau on the southwest corner of the island.  Photographs were taken.  These pictures included those taken from a minimum of altitude of 200 feet to 9,000 feet.  The high altitude shots were made from east due to sun location; partial cloud cover did not permit photography of all aspects of the island.\r\n   'Lava flow was to the west only in one large stream to the west from the crater, turning and flowing toward the water line on the southwest corner.  The other three sides of the island appeared unaffected with only a light covering of dust visible.  The billowing columns of steam and smoke coming from the crater were very white, turning grey to darker shades at intervals.  Seals in large numbers still inhabited the entire west shoreline of the island.'\"","StartYear":1963,"StartMonth":2,"StartDay":13,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1963,"EndMonth":2,"EndDay":28,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Amukta","ParentVolcano":"Amukta","VolcanoID":"ak10","ParentVolcanoID":"ak10"},{"ID":367,"Name":"Augustine 1963/10","Description":"   From Kienle and Swanson (1985): \"On October 11, 1963, Augustine burst into activity again, sending an ash column to about 3,000 m and a pyroclastic flow down the flank of the volcano, which set fire to brush on the lower slopes.  According to Detterman (1968), the eruption continued intermittently for about 10 months, with major explosions recorded on November 17, 1963, July 5 and August 19, 1964.  Presumably, during one or more of the earlier vent clearing eruptions in late 1963 ash was dispersed in a northeasterly direction and preserved in the varved sediments of Skilak Lake, 210 km distant (Rymer and Sims, 1976). \r\n     \"According to reports from field parties of the Pan American Petroleum Corporation (D.H. Reno, communication to R.B. Forbes) there was no unusual precursor activity during the summer 1963 field season, which terminated mid-July, but in the June-July 1964 field season the volcano was reported to be quite active and considerable ash was encountered on the mountains on the mainland up to 15 km west of Augustine.  Where the ash was not disturbed it was a maximum of about 2.5 cm deep.  \r\n     \"Detterman (1968) reports that the cone emitted smoke and steam all through 1965 and 1966, before he actually visited the island to map the deposits of the 1963/64 eruption in 1967.  Detterman thought that the initial eruption was a nuee ardente eruption directed toward the southeast and originating at the base of the 1935 summit tholoid.  It allegedly blew out a section of crater wall '3,200 feet long, 500 feet high and 700 feet thick'. \r\n     \"The 1963/64 eruptions greatly altered the summit configuration and finally a new dome emerged in the new crater southeast of the remnant of the 1935 summit tholoid.  By September 1964 it had completely filled the crater, engulfed what was left of the eastern and southern crater rim and stood much higher than the original 1935 summit.\"\r\n   Detterman (1968) estimates the volume of debris flow at 0.09 cubic km, an estimate considered high by Kienle and Swanson (1985).  Newhall and Melson (1983) list a \"new dome\" volume of 0.066 cubic km.","StartYear":1963,"StartMonth":10,"StartDay":11,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1964,"EndMonth":8,"EndDay":19,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":376,"Name":"Shishaldin 1963/12","Description":"   Coats (1964) reported an eruption at Shishaldin, December 28-31, 1963.","StartYear":1963,"StartMonth":12,"StartDay":28,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1963,"EndMonth":12,"EndDay":31,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":276,"Name":"Westdahl 1964/3","Description":"   Juergen Kienle's compiled notes on file at the Geophysical Institute, University of Alaska Fairbanks, state that  Skinner reported in 1979 that during late 1964 to early 1965, 7 separate \"blow holes\" of ash on E-W line were active at Westdahl.  He also states that across a plateau south of Pogromni, just before it slopes off to Bering Sea, there was activity for 1 week, there was a deep gully connecting all blow holes in snow field, and at the end of the week, the main fissure had completely stopped, but a new cone had formed 3 miles from the Bering Sea beach (with lava flow).\r\n   Reeder and Doukas (1994) report that Westdahl erupted in 1964-65, producing a fissure-fed lava flow that eventually covered 35 square kilometers.\r\n   Coats (1964) writes that tremors were reported at Scotch Cap, and that although there was lava, the composition is unknown.  Coarse tephra was also produced.  On April 16, the vent was only steaming slightly.  Secondary fumaroles were seen on the lava flow.\r\n   The Associated Press produced an article on March 14, 1964: \"A major new volcanic eruption was reported late Friday on Unimak Island in the Aleutian chain, with a two-mile river of lava flowing from the mountain's crater and debris hurled 2,000 feet into the air.  \r\n   \"The lava flow and spewing debris was reported by a Coast Guard plane flying a low-level survey about five miles east of Westdahl peak, on Pogromni volcano at the west end of Unimak.\"","StartYear":1964,"StartMonth":3,"StartDay":10,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1964,"EndMonth":4,"EndDay":16,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Westdahl","ParentVolcano":"Westdahl","VolcanoID":"ak322","ParentVolcanoID":"ak322"},{"ID":4,"Name":"Kiska 1964/3","Description":"   Coats (1964) reported an eruption of Kiska volcano beginning March 18, 1964, from a flank cone, with lava flow, and speculates that the 1964 eruption is \"essentially one eruption\" with the earlier 1962 eruption.  He also states that \"the explosive phase has stopped but lava flow continues.\"","StartYear":1964,"StartMonth":3,"StartDay":18,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kiska","ParentVolcano":"Kiska","VolcanoID":"ak161","ParentVolcanoID":"ak161"},{"ID":461,"Name":"Griggs 1965","Description":"   Ward and Matumoto (1967) report seeing a \"very active fumarole high on the west flank\" of Mt. Griggs during 1965.  This activity does not constitute a volcanic eruption.","StartYear":1965,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Griggs","ParentVolcano":"Griggs","VolcanoID":"ak112","ParentVolcanoID":"ak112"},{"ID":439,"Name":"Redoubt 1965/1","Description":"   From Till and others (1993): \"In January and February of 1965, pilots reported that five fissures had opened on the southeast wall of Redoubt and were emitting water vapor and hot gases (Anchorage Daily News, January 29 and 30, 1965; Fairbanks Daily News-Miner, February 4, 1965).\"  This activity does not constitute a volcanic eruption.\r\n   From the Associated Press (1965): \"A fifth fissure has opened high on the southeast wall of troubled Mt. Redoubt, 125 miles southwest of here.\r\n   \"Capt. Victor L. Fonday, Northern Consolidated Airlines pilot, reported new activity on the mountain yesterday.  He said he flew to within a thousand feet of the mountain Tuesday and saw wisps of steam coming from the new fissure.\r\n   \"Volcanic activity was observed at the 10,197 foot mountain by airline pilots last week.  The U.S. Geological Survey office in Anchorage said it is the first reported volcanic activity on the mountain since 1933.   \r\n   \"Fondy [sic] said he circled the volcano twice to get a close-up view.  He said four fissures, opened on the mountain last week, are continuing to pour out hot gasses and steam.\"","StartYear":1965,"StartMonth":1,"StartDay":28,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Redoubt","ParentVolcano":"Redoubt","VolcanoID":"ak231","ParentVolcanoID":"ak231"},{"ID":312,"Name":"Spurr 1965/1","Description":"   On January 31, 1965 an Elmendorf Air Force Base pilot reported hot ashes in the crater and said the crater appeared to be greenish in color (Anchorage Daily Times, unknown author, 1965).  On February 2 a Northern Consolidation pilot reported seeing smoke and steam clouds (Associated Press, 1965).  This activity may not constitute an eruption.","StartYear":1965,"StartMonth":1,"StartDay":31,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1965,"EndMonth":2,"EndDay":2,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Spurr","ParentVolcano":"Spurr","VolcanoID":"ak260","ParentVolcanoID":"ak260"},{"ID":556,"Name":"Fourpeaked 1965/7","Description":"   In October, 2006, Oliver Holm of Kodiak, AK, phoned the Anchorage Alaska Volcano Observatory office to report seeing a steam and gas plume at or near the summit of Fourpeaked in 1965.  Mr. Holm stated that during July or August of 1965 he was setnetting in Chief Cove, at the northern side of Uyak Bay.  One day he went up Shelikof Strait, and as they passed Cape Ugat (on the western side of Kodiak Island, he could see a steam plume coming from at or near the summit of Fourpeaked.  Mr. Holm reports that the plume was about the same height as the mountain is tall, from his perspective.  He did not notice any ash on the snow, or any discoloration in the plume.","StartYear":1965,"StartMonth":7,"StartDay":null,"StartTime":null,"StartQualifier":2,"StartQualifierUnit":"Months","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Fourpeaked","ParentVolcano":"Fourpeaked","VolcanoID":"ak103","ParentVolcanoID":"ak103"},{"ID":468,"Name":"Martin 1965/8","Description":"   Ward and Matumoto (1967) note that \"During August 3-5, 1965, pulverized ash filled the air in the region from the Valley of Ten Thousand Smokes to Brooks Lake.  Although several people were within ten miles of Mts. Trident and Martin, the suspected sources, no aerial or ground reconnaissance could establish whether this ash was of volcanic origin or simply windblown (Ward and Ward, 1966.)\"  Ward also notes that Mt. Martin \"fumed steadily\" during 1965.\r\n      However, Miller and others (1998) don't believe that this is an eruption account, saying \"all reports of eruption or ash emission are probably spurious, reflecting only the persistent and conspicuous steam plume.  Steam emission is normally vigorous and continuous from the summit vent of Mount Martin with plumes occasionally rising 600 m above the vent and extending downwind for 20 km.\"  Additionally, the 1965 event could simply be 1912 Novarupta ash remobilized by strong winds.","StartYear":1965,"StartMonth":8,"StartDay":3,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1965,"EndMonth":8,"EndDay":5,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Martin","ParentVolcano":"Martin","VolcanoID":"ak189","ParentVolcanoID":"ak189"},{"ID":441,"Name":"Redoubt 1966/1","Description":"   From Till and others (1993): \"[O]n January 24, 1966, Redoubt erupted.  'Giant black puffs' of tephra rising 6,000 m above the summit were reported (Anchorage Daily News, January 25, 1966).  A 22-man seismic crew camping and working along the lower Drift River was evacuated following flooding of the river as a result of the eruption.  According to their account (Anchorage Daily News, January 26, 1966), the ice-bound river broke up suddenly and water rose 1 to 1.2 m in 15 minutes, carrying chunks of ice 'the size of a D-7 cat'.  The flood crested and returned to normal within about 30 minutes.  During this flood, boulders with mean diameters of 1 to 2 m were deposited within approximately 3 to 5 km of the volcano.  Other smaller floods occurred through February and March (Sturm and others, 1986).  \r\n   \"Infrasonic waves attributed to explosive eruptions of Redoubt were recorded 550 kilometers away at College, Alaska, during two periods: six explosions from January 24 to February 20, 1966, and five explosions from December 7, 1967, to April 28, 1968 (Wilson and Forbes, 1969).\"\r\n   \"* * * Sturm and others (1986), in a study of long-term effects of the eruptions on the Drift glacier that drains the summit crater, estimated that 60,000,000 cubic m (0.6 cubic km) of ice were 'blasted, melted, scoured, or washed away by the cumulative events of 1966-68.'  When parts of the glacier that were separated by the eruption reconnected, a dramatic thickening of the lower glacier occurred and the surface speed increased by a factor of ten.  This surge apparently culminated in 1986 without causing a damming of the Drift River.\"","StartYear":1966,"StartMonth":1,"StartDay":24,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1968,"EndMonth":4,"EndDay":28,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Redoubt","ParentVolcano":"Redoubt","VolcanoID":"ak231","ParentVolcanoID":"ak231"},{"ID":211,"Name":"Pavlof 1966/3","Description":"   The earliest accounts of this eruption are from Associated Press articles in the Fairbanks Daily News Miner.  The March 3, 1966 edition contained this information: \"A 200-foot stream of lava was reported erupting from Mt. Pavlof Wednesday night by a Coast Guard aircraft crew flying over the Alaska volcano.\r\n   \"The spectacular sight was reported at Elmendorf Air Force Base by Lt. Cmndr. Paul H. Breed, pilot of the Coast Guard plane on a training flight out of Kodiak.\r\n   \" * * * Robbins [area manager for the Federal Aviation Administration at Cold Bay] reported the eruption was not visible from Cold Bay because of a low ceiling covering the 2,100 foot peak.\r\n   \"A spokesman for the Alaska Disaster Office in Anchorage said the winds were blowing in a southwesterly direction and would probably carry any debris from the eruption seaward.\"\r\n   Jacob and Hauksson (1983) report an eruption at Pavlof around March 15, 1966 and describe it as an eruption in the central crater, with normal explosions, and note that \"during the 1950s and 1960s the active vent was never exactly located, it shifted around with each eruption high on NE or NNE flank.\"\r\n   An Associated Press article from March 16, 1966, describes the eruption: \"Lava was reported pouring down three sides of Mt. Pavlof Tuesday by the crew of a Coast Guard plane that flew near the Aleutian Island volcano.\r\n   \"Mt. Pavlof * * * was reported hurling rocks 500 feet high and emitting a dense column of smoke that reached 15,000 feet. \r\n   \"Lt. J.E. Mitts, pilot of the plane, reported his sighting to the Coast Guard station at Kodiak.  The plane, with a four-man crew, was on its way to St. Paul Island on a routine supply mission.\r\n   \"Mitts reported that lava was pouring down the north, east, and west sides of the mountain.  He told his headquarters at Kodiak that he flew his plane, a C123, within a half mile of the mountain.\"","StartYear":1966,"StartMonth":3,"StartDay":2,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1966,"EndMonth":3,"EndDay":15,"EndTime":null,"EndQualifier":14,"EndQualifierUnit":"Days","Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":377,"Name":"Shishaldin 1967/1","Description":"   Decker (1967) reports that on January 28, 1967, Shishaldin had an explosive eruption.  He writes that \"[a]sh charged clouds succeeded by intense steam emission. No lava reported.\"","StartYear":1967,"StartMonth":1,"StartDay":28,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":5,"Name":"Kiska 1969/9","Description":"   Miller and others (1998) \"Coast and Geodetic Survey personnel recorded renewed activity on Kiska Island in early September, 1969; an ash column was observed rising to 400 m and steam to 4000 m.  \"Flames\" and what appeared to be lava were reportedly visible from Amchitka, 80 km distant.  On September 16, strong sulfur odors, air temperatures elevated by 10 to 15 degrees C, and possible evidence of a small lava flow were noted during a military flight over north Kiska Island (Smithsonian Institution, 1969; eyewitness accounts on file at Geophysical Institute, University of Alaska, Fairbanks.)\"\r\n   Smithsonian Institution, 1969, CSLP Card 0751: (12 September 1969) Ash to about 1,200 feet and steam plumes to about 12,000 feet and lava seen; source uncertain\r\n   Smithsonian Institution, CSLP Card 0752: (17 September 1969) Overflights identify Kiska as source of activity","StartYear":1969,"StartMonth":9,"StartDay":11,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1969,"EndMonth":9,"EndDay":16,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Kiska","ParentVolcano":"Kiska","VolcanoID":"ak161","ParentVolcanoID":"ak161"},{"ID":181,"Name":"Chiginagak 1971/7","Description":"   From Miller and others (1998): \"Mr. Odon Soeth reported observing an ash eruption in July, 1971 from Port Heiden, 100 km southwest of Chiginagak; according to Mr. Soeth, the eruption lasted only one evening.\"","StartYear":1971,"StartMonth":7,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1971,"EndMonth":7,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Chiginagak","ParentVolcano":"Chiginagak","VolcanoID":"ak49","ParentVolcanoID":"ak49"},{"ID":371,"Name":"Augustine 1971/9","Description":"   From Kienle and Swanson (1985): \"A photograph taken during the [earthquake] swarm by Austin Post of the U.S. Geological survey on September 3 shows a strong plume fed by very active fumaroles on the 1964 lava dome.  A small ash eruption and incandescence (red glow) on the flank of the volcano was seen during the late evening twilight of October 7 from a fishing boat 38 km north of the volcano.  The eruption is corroborated by seismic tremor, which was recorded on both of the then existing seismic stations between 23 and 01 hours on October 7/8.\"\r\n   Waitt and Beget also describe this event: \"In September-October 1971 billowing fumaroles and a report of incandescence followed an earthquake swarm within the volcanic cone in late August and early September (Kienle and Swanson, 1980, 1985, p. 25-28).\"","StartYear":1971,"StartMonth":9,"StartDay":2,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1971,"EndMonth":10,"EndDay":7,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":253,"Name":"Akutan 1972/2","Description":"   From Shackelford (1976): \"The crew of the S.S. Summit observed Akutan in eruption at 0900 GMT on 11 February 1974.  Ejecta was thrown to heights exceeding 100 meters, while a lava flow poured down the west flank of the volcano toward the Lava Bight.  The lava flow was several hundred meters in length.  The eruption was of a pulsating, intermittent nature (Information from Smithsonian Institution, 1974).  \r\n   \"Since the original report said that the lava was flowing down the side of the 634 m peak, and because Akutan is 1293 m tall, it may well have been a flank eruption.\"","StartYear":1972,"StartMonth":2,"StartDay":11,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":252,"Name":"Akutan 1972/9","Description":"   From Stone (1975): \"Pilots from Reeve-Aleutian Airways reported on 22 May 1973 that the Akutan volcano apparently had been erupting ash and steam for several months. \r\n   \"A survey of ERTS satellite data from past months revealed that Image No. 1056-21331 of 17 September 1972 showed the mountain to be essentially snow-free as contrasted with other nearby peaks at similar altitudes.\"","StartYear":1972,"StartMonth":9,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1973,"EndMonth":5,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":71,"Name":"Korovin 1973/8","Description":"   From Reeder (1988): \"In the evening (just at dusk) of 25 (+/- 2) August 1973, eruptive activity was seen by numerous residents of Atka village while they were on a U.S. Navy harbor tug that was transporting them from Atka village to Adak.  The harbor tug maintained a distance of about 9 km from the northern shore of Atka Island as it passed Korovin volcano.  An incandescent 10+ m wide active lava-flow channel was observed that extended from a fissure vent the northern summit of Korovin volcano to about half of the way down the northern flank of the volcano.  The incandescent lava-flow channel then ended or went out of view underneath the surface.  Some minor rock avalanching down the northern side of the volcano to the Bering Sea was remembered by some of the passengers.  No steam emission from the shoreline and no ash emission from the summit of the volcano were noted.\"","StartYear":1973,"StartMonth":8,"StartDay":25,"StartTime":null,"StartQualifier":2,"StartQualifierUnit":"Days","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Korovin","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak171","ParentVolcanoID":"ak17"},{"ID":212,"Name":"Pavlof 1973/11","Description":"   Stone and Kienle (1975) report: \"An eruption of the Pavlof Volcano was observed at 10:00 p.m. local time 12 November (0800 GMT 13 November) from a location some 33 km from the summit.  The observers reported seeing 'shooting flames,' coupled with a possible lava flow down the northwest flank.\r\n   \"A seismometer located 7 km southeast of the summit recorded increased micro-earthquake activity coincident with the time of the reported lava eruption.\r\n   \"Seismic records showed onset of harmonic tremor on 13 November, 07:00 AST, coincident with the reported eruption of lava.\"\r\n   McNutt (1985) estimates the total dense rock equivalent volume of eruptive material for this eruption as 4.8 - 7.9 x 10^6 cubic meters.  McNutt (1999) estimates the total dense rock equivalent volume of eruptive material for this eruption as 6.4 x10^6 cubic meters.","StartYear":1973,"StartMonth":11,"StartDay":12,"StartTime":"22:00:00","StartQualifier":null,"StartQualifierUnit":"","EndYear":1973,"EndMonth":11,"EndDay":13,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":58,"Name":"Great Sitkin 1974/2","Description":"   From Associated Press (1974): \"A spokesman for the Adak Seismological Observatory, a mere 23 miles away from the volcano, said the eruption was reported at 6:58 p.m. BDT and created 'a perfect mushroom cloud.'  He said the clouds arose to at least 10,000 to 12,000 feet within four minutes of the eruption and was colored a dirty white to a light beige.\" AVO has several photographs of a Great Sitkin eruption plume, taken from Adak.. . . \r\n\"'It was a very spectacular explosion,' he said, 'but we don't know its type yet.  It could be a steam explosion or a genuine volcanic eruption.'\"\r\n   \"The spokesman said witnesses saw a number of bright flashes as the mushroom cloud boiled its way up lending credence to the possibility of volcanic origin.\"\r\n   \"He said it was not known if anyone actually heard the blast but he noted a number of witnesses said they heard a deep rumble shortly before the eruption.\"\r\n   From Smithsonian Institution, 1974, CSLP Report 1804: (22 February 1974): Explosive activity and light-colored plume\r\n   The following was cabled from the Geophysical Institute on 22 February 1974. \"Explosive activity was observed at 1855 local time from Adak, 48 km WSW of Great Sitkin volcano. An earthquake originating at the volcano of Richter magnitude 2.6 occurred at the time of onset. An estimated 10,000-foot light-colored plume was reported over the summit at dusk. Since that time bad weather has obscured the island.\"\r\n\r\nSmithsonian Institution, 1974, CSLP Report 1938: (30 September 1974): Lava dome still growing, overspilling crater rim\r\n   \"D. Glover reported that, on a helicopter inspection trip to the volcano on 22 February, he '. . . Found that a large lava dome had been emplaced in the crater, with mostly steam and gas being emitted.' Foul weather prevented observations on all but three occasions between then and 29 March. About one week after the eruption, he noted, through a high-power telescope, '. . . That the dome had been extruded a considerable extent, with some ash being emitted. Since then activity has decreased to steam and gas emissions.'\r\n   \"In mid-September, he reported that he had '. . . Only been able to observe Great Sitkin volcano by high-power telescope and a few times from aircraft. The lava dome appears to continue to extrude with minor lava flows spilling over the lip of the crater. The size of the dome is hard to estimate but it is probably close to 700 m in diameter and 200-300 m high. We have recently installed seismic instrumentation on the volcano but we have not noticed any unusual activity.' In summary, it appears that, following the initial release of the pressure head of volatiles on 19 February a dome has been extruded in the caldera of Great Sitkin. The new dome appears to be about the size of that extruded in 1945. Further, the dome is still active, overspilling the lip of the caldera as it grows. The extrusion has been quiet, with little of no associated explosiveness.\"\r\n   Newhall and Melson (1983) estimate the size of this dome at 96x10^6 cubic meters.","StartYear":1974,"StartMonth":2,"StartDay":19,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1974,"EndMonth":9,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":213,"Name":"Pavlof 1974/3","Description":"   Jacob and Hauksson (1983) write that during March 14-24, 1974, Pavlof experienced a \"period of probable weak ash emissions.  Explosion earthquakes recorded.\"","StartYear":1974,"StartMonth":3,"StartDay":14,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1974,"EndMonth":3,"EndDay":24,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":214,"Name":"Pavlof 1974/9","Description":"   Jacob and Hauksson (1983) write that between September 2, 1974 and January 6, 1975, Pavlof experienced an \"eruption in central crater, and normal explosions, with moderate ash eruptions, plume rising to max 6 km ASL.  Reports of lava flow may be incorrect.  Explosions and intermittent tremor recorded.\"  McNutt (1985) reports several discrete periods of explosion quakes during this time: October 29 - November 17, 1974; November 25 - December 16, 1974; December 25, 1974 - January 6, 1975.","StartYear":1974,"StartMonth":9,"StartDay":2,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1975,"EndMonth":1,"EndDay":6,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":295,"Name":"Cleveland 1975/9","Description":"   From Shackelford (1977): \"An unconfirmed report indicated that Mt. Cleveland was erupting at about the same time as the September eruptions of Shishaldin.  No other information currently available.  The author acknowledges T.P. Miller for the receipt of this information.\"","StartYear":1975,"StartMonth":9,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":215,"Name":"Pavlof 1975/9","Description":"   Pavlof volcano was in eruption nearly continuously from September 13, 1975 until March, 1977.  Jacob and Hauksson (1983) summarize the 1975-1976 activity as follows: \"13 September - 06 October, 1975: Period of generally weak ash emissions, often likened to the chugging of a locomotive.  Both harmonic tremor and explosion earthquakes recorded.  Strong tremor recorded 13-15 and 23-24 September with increased activity.  Possible lava flow observed in October.  09 September, 1976 - 04 December, 1976: Period of weak ash emissions including several episodes of stronger activity.  Ash fall (light) at Sand Point on 09 September.  Harmonic tremor recorded on 09 September, 18-22 October, and 10-22 November.  Possible lava flow observed in December, may be spatter-fed or a lahar.  Many explosions recorded, including some strong enough to be felt in Pavlof Bay (15-20 km).\"\r\n   Shackleford (1977) summarizes the 1975 activity as follows: \"Ash eruptions began from Pavlof on 13 September, 1975.  There was no preceding rise in microearthquake frequency.  Strongest activity took place in the months of September-October, ash columns achieving a height of 2400 m.  A lava flow was reported moving down the N flank on 31 October, but similar observations in 1973 and 1974 were subsequently shown to be in error, so this report may be in error also.  It may well be a lahar.  Activity increased somewhat in December, with sporadic appearances of lava fountaining amidst the ash clouds.  It was reported that 18:15 GMT 28 December saw a 30 sec. burst of lava from Pavlof that resembled a blow torch, was visible in broad daylight.  From 03:55 to 04:10 GMT on 31 December a continuous series of lava pulses surged to heights of at least 150 m above the cone.  One observer likened the activity of Pavlof to the chugging of a locomotive, rather than a steady state ash emission.\r\n   \"Harmonic tremor has been recorded during eruptive periods, as well as explosion signatures.  Some of the explosions have been strong enough to rock fishing boats 10-15 km away, in Pavlof Bay.\"\r\n  Matthew Sturm sent AVO an eyewitness account of the October 1975 lava flow, which he observed on October 7. His journal for that day reads: \"During the night run the watch saw numerous red distress flares south of the ship and diverted to investigate. As they worked south, it became clear the flares were being sent up well inland on the Alaskan Peninsula, at which point it dawned on someone that perhaps it wasn’t flares at all. A little bit of trigonometry and it was soon clear that we were seeing Pavlof Volcano erupting. But just to be sure we stayed around and as the sun rose we could see a huge cloud above the 8200’ peak with red sparks embedded in the black cloud, while on the northern slopes below the summit we could make out black ash and lava spilling over the snow and glaciers on the upper reaches of the mountain. The volcano would be peaceful for a few minutes, then suddenly a cloud would jet up and billow out for three or four thousand feet above the mountain. The entire crew was mesmerized by the sight and we stayed there for over an hour watching.\"\r\n   Shackleford (1978) summarizes the 1976-1977 activity as follows: \"Strombolian eruptions which began in September 1975 continued throughout 1976 and were continuing in 1977.  In 1976 activity was at a somewhat lesser level than the preceding year.  Possible lava flows reported in February and December.\"  Please see Shackleford (1978) for a month-by-month description of activity.\r\n   Shackleford (1979) continues to summarize the activity in 1977: \"Reports of the 1977 Pavlof activity are extremely sketchy and incomplete, in part due to very poor weather conditions.  Since March 1977 there have been no reports of activity (which may well have continued beyond March) due to a lack of reporting personnel, rather than a lack of activity.\"  Please see Shackleford (1979) for a month-by-month summary of 1977 activity.\r\n   McNutt (1999) calculates an eruptive volume of greater than 14.6 x10^6 cubic meters (dense rock equivalent) during the time period from September 13, 1975 through November 10, 1977.","StartYear":1975,"StartMonth":9,"StartDay":13,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1977,"EndMonth":3,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":378,"Name":"Shishaldin 1975/9","Description":"   From Smithsonian Institution (1975): \"Shishaldin, during the few times it could be observed from Cold Bay, was seen to be continually active in September and into October. At 2215 on 16 September, NOAA's RV Millard Freeman, at 55.55N, 163.82W experienced rainfall that contained ash. This continued for 15 minutes while the ship was headed on course 250 true. The ash eruptions had apparently ceased by the end of October.\"","StartYear":1975,"StartMonth":9,"StartDay":16,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1975,"EndMonth":10,"EndDay":31,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":72,"Name":"Korovin 1976","Description":"   From Miller and others (1998): \"'Smoke' was observed in 1976 at Korovin from Atka village, located 20 km to the south (Arctic Environmental Information and Data Center, 1978).","StartYear":1976,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Korovin","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak171","ParentVolcanoID":"ak17"},{"ID":380,"Name":"Augustine 1976/1","Description":"   From Shackelford (1978): \"In the morning of 22 January Augustine began a period of major activity from a new vent located at the contact of the 1935 and 1964 domes.  The first major eruption began at 0740 AST on 23 January.  On that date there were at least 8 major eruptions, one was at 1618 AST.  An additional 4 major explosive outbreaks took place on 24-25 January.  The eruption clouds pierced the tropopause, reaching heights + 10,000 m to 14,000 m a.s.l.  Ash falls took place at Iliamna, Homer, Seldovia, and Anchorage (1.5mm).  The January eruptions explosively removed most of the summit 1964 dome, forming a crater breached to the N.\r\n    \"* * * The explosive activity was accompanied by major pyroclastic flows, and mudflows and lahars.  The January glowing avalanches spread radially over the island, reaching the sea on the S, NE, and NW flanks.  The Burr Point Research Station (NW tip of island) was severely damaged by one or more avalanches, although protected by a ridge, as a result of a back eddy in the clouds.  Several days afterwards, temperatures in the pyroclastic flow deposit exceeded 400 degrees C at a depth of 2.7 (deposit is on the NE slope).  There was an active fumarole field at the distal end of the deposit.  Augustine was relatively quiet from 26 January to 5 February.\r\n     \"The second cycle of eruptions began with the renewal of major activity at 0443 on 6 February, resulting in falls of ash and mud along the Kenai Peninsula.  A strong eruption at 1230 on the 6th produced a cloud that rose to a height of 8-9 km.  A blizzard-like ash fall at Homer on the 6th was the heaviest of the entire eruption, prohibiting vehicular traffic because of the induced darkness at 1800.  Eruptions generally ended on the 15th, producing eruption plumes that usually rose to heights of 3-4, 5 km.  Again, there was production of major pyroclastic flows which followed the same paths as those of January.  The January flows had formed a new beach on the NE part of the island, and a further extension of this beach resulted from the glowing avalanches of February * * * Activity on the 16th consisted of occasional steam explosions.  On the 18th there were a few ash-laden puffs rising from Augustine.  Observations on that date showed that a new tholoid had formed in the new crater, probably on the 12th and 13th which was a period of continuous harmonic tremor.  The new dome was found to be about 260 m above its base. From 19 February to April another quiet period ensued, although there were some block and ash flows off of the new dome beginning in late February.  There was some earthquake swarm activity on 15 to 25 March.\r\n     \"The third and last cycle took place in April.  In the early part of the month explosion earthquakes began to be recorded on the new seismic array.  The number of eruptions as follows: 6-12 eruptions per day during 6-9 April, 1 eruption per hour on 10-11 April, almost continuous intense eruptions during 12-18 April, 12 eruptions per day on 18-22 April.  Eruptive behavior returned to low levels on the 23rd.  Since 24 April there have been no further eruptions, just quiet degassing from the new dome, with some spectacular plumes reported.  The April explosive activity was accompanied by block and ash flows shed off the new dome, which underwent a period of renewed growth in April.\"\r\n   David Johnston (1978) calculates that \"roughly 0.17 cubic km of rock was erupted in 1976, of which about 27% was erupted in January, 59% in February, and 14% in April.  Fifty-three percent of the volume is in pyroclastic flow deposits, 38% in the lava dome, and 8% in ash-fall and pyroclastic surge deposits.  Ejecta erupted in January include approximately 10% andesite scoria, 50% dacite pumice, and 40% hybrid and banded pumices.\"  \r\n   Kienle and Swanson (1985) have slightly different volume estimates for this eruption: \"* * * the estimated bulk volume of the ejecta from the 1976 eruption is about 0.4 cubic km, of which 0.06 cubic km are flows on the island itself and the rest [0.339 cubic km] is tephra.  We arrived at this estimate by digitizing the the pre- and post-eruption topography of the sector most affected by debris flow activity, the northeast sector of the Island (see Figure 31 in original text) and by using conservative estimates of the total thickness of tephra accumulation for the area that was affected by ash falls (See Figure 15 in original text).\"","StartYear":1976,"StartMonth":1,"StartDay":22,"StartTime":"17:59:00","StartQualifier":null,"StartQualifierUnit":"","EndYear":1976,"EndMonth":4,"EndDay":24,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":379,"Name":"Shishaldin 1976/4","Description":"   From Shackelford (1978): \"From April to November 1976 Shishaldin volcano occasionally displayed weak explosive activity from the summit, with intervals of steaming.  Frequent poor weather obscured the volcano, so the following observations are incomplete to an unknown degree.  Cited times are local time, except those of August, which are GMT.\"\r\n   April 6th, some radial ash sprays on the snow were visible at 16:00; April 27th, at 12:10 there was a faint veil-like ash cloud over the summit.  In 10 minutes it had disappeared, leaving new ash on the surface of the snow.  Also observed was a black streak extending 5-10 km down the NW flank form the summit to about 300 m a.s.l.; April 30th, ash on the snow surface, more apparent than when visible on the 29th (Shackelford, 1978).\r\n   May 14th, dark ash visible on the cone; May 16th, ash on snow, May 20th, the NE flank had an extensive ash cover between 1600 and 2500 m a.s.l (Shackelford, 1978).\r\n   June 3rd, ash on snow (?); June 4th, occasional ash eruptions were noted between 09:00 and 21:00.  The visible flanks were about 70% ash-covered; June 10th, at 15:30 there were intermittent black smoke emissions.  Although no longer erupting at 21:00, Shishaldin's upper 600 m were mantled with ash; June 22nd, ash on NE flank over the snow surface; June 27th, light to heavy ash cover on the cone above about 1500 m a.s.l (Shackelford, 1978).\r\n   July 6th, between 14:00 and 22:00 dark ash was observed falling on the N flank; July 8th, smoke and ash eruptions were visible during the period 22:00 to 23:00 (Shackelford, 1978).\r\n   August 4th, an intensification of the steam emission began after 02:00, becoming 'smoke' after 16:15.  There was no observation of a new ash-fall however.  By the 30th an estimated 90% of the ash had been blown off Shishaldin (Shackelford, 1978).\r\n   September 27th there was a 1 minute projection of a jet of incandescent gas which recurved to the S; September 28th, observations at 06:50 showed the volcano to be occasionally erupting ash clouds (Shackelford, 1978).\r\n   October 24th, during the period 16:05 to 17:30 there were puffs of dense smoke observed, with intervals of approximately 5 minutes between puffs, which moved (were blown?) downhill some 100 m down the E flank (Shackelford, 1978).\r\n   According to the Smithsonian Institution (1976), Shishaldin continued to steam throughout November, 1976.\r\n   In February, 1977, ash emission from Shishaldin was observed on February 14 or 15, and on the 27th, by Peninsula Airways pilots (Smithsonian Institution, 1977).","StartYear":1976,"StartMonth":4,"StartDay":6,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1977,"EndMonth":2,"EndDay":27,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":254,"Name":"Akutan 1976/10","Description":"   From Shackelford (1979): \"Sporadic ash eruptions, which began in fall 1976, were still continuing as of May 1977.  Observations of the activity during May 1977 showed explosive ejection of light brown ash clouds (every 1/4 hour between 17:00 and 20:00 on 5 May) with the ash cloud drifting N.  During the inter-eruption periods, white fume emission occurred.  Incandescent tephra was noted on 6 May at 17:30, and further eruptions were noted the following day.  Similar activity was noted on 9 May.  It is not unlikely that this explosive activity continued beyond the last date of observed activity, as Akutan typically is in a state of mild explosive activity lasting months or years.  No further information known to this reporter.\"","StartYear":1976,"StartMonth":10,"StartDay":null,"StartTime":null,"StartQualifier":2,"StartQualifierUnit":"Months","EndYear":1977,"EndMonth":5,"EndDay":9,"EndTime":null,"EndQualifier":2,"EndQualifierUnit":"Months","Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":87,"Name":"Pyre Peak 1977/3","Description":"   From Miller and others (1998): \"In early March, 1977 the crew of the U.S. Coast Guard Cutter Mellon reported eruptive activity.  Eight lava fountains, up to 90 m high were  noted along a radial rift about 1 km long and about 2.5 km southwest of the summit.  At least two tongues of lava were extruded.  The larger flow, 1 km wide, extended 1 km south.  Neither tongue entered the sea.  Pyroclastic material was also produced during the event.  Dense clouds containing black ash and incandescent fragments were emitted from one or both of the vents effusing lava, and a coating of fine ash was visible on the surrounding snow.  By March 8th, lava extrusion had apparently ceased, but a considerable amount of steam, possibly containing some ash, was still being discharged (Anchorage Times, March 8, 1977; Smithsonian Institution, 1977).\"  Although Miller and others (1998) cite the Anchorage Times, March 8th, as the source of the news article, the article appears in the March 7th edition.\r\n   The March 7, 1977, Anchorage Times article states: \"A volcanic eruption on Seguam Island in the Aleutian Chain yesterday morning shot smoke and fire hundreds of feet into the air, a U.S. Coast Guard spokesman said this mroning.\r\n   \"A Coast Guard cutter spotted the eruption shortly after 7 a.m., Anchorage Time, and radioed a report to Coast Guard headquarters in Junear.\r\n   \"'Fountains' of smoke and fire were steadily being spewed 100 to 200 feet into the air from the mouth of the voclano, Captain Hal Olson, commander of the cutter Mellon, reported.\r\n   \"'The flow divides into two tongues - the smaller moving southerly approximately 1/2-mile long and 1/4 mile wide, the large moving steadily about 1 1/2 miles long by 1/2 mile wide,' Olson reported.\r\n   \"Two vents, or mouths, of the volcano were erupting, with lava and black smoke flowing from both.\r\n   \"No earthquakes occurred from the eruption although it was reported to be one of the largest in the area, a spokesman for the Palmer Observatory said.\r\n   \"Seismic stations on Adak and Nikolski Islands, located on each side of Seguam Island, did not pick up readings leading scientists to believe little or no seismic action followed the eruption.\r\n   \"Seguam Island, about 160 miles east of Adak Island, is uninhabited.  The island is about 15 miles long and five miles wide.\r\n   \"The 37-foot cutter, normally based in Honolulu, was on fisheries patrol off the Aleutian Islands.\"\r\n   Jicha and Singer (2006) measure the present volume of material erupted during the 1977 eruptions as 0.06 cubic km (6x10^7 cubic m).","StartYear":1977,"StartMonth":3,"StartDay":6,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1977,"EndMonth":3,"EndDay":8,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Pyre Peak","ParentVolcano":"Seguam","VolcanoID":"ak224","ParentVolcanoID":"ak246"},{"ID":281,"Name":"Ukinrek Maars 1977/3","Description":"   From Kienle and others (1980): \"The first explosions were observed on March 30, 1977, about 4:00 a.m. Alaska Standard Time (AST), from Egegik, 65 km northwest of the eruption site.  A fine ash fall occurred that day at Larsen Bay, Kodiak Island, 160 km east of the maars, and a sulfurous haze layer lay over the city of Kodiak, 250 km to the east.  Fine ash fell over some 20,000 - 25,000 square km, but significant ash accumulation was restricted to a radius of about 3 km from the maars.  During the day, the Federal Aviation Administration (FAA) in King Salmon received reports from pilots of steam and ash columns reaching heights of 300-600 m.  Two King Salmon pilots independently overflew the eruption site in the late afternoon (17:00 AST) and witnessed a steam and ash plume rising 1500 m before billowing out and eventually reaching about 6500 m, the maximum height reported during the eruptions.  The source of the explosions was a single vent, 30-35 m in diameter, located at an elevation of approximately 70 m above sea level on a short ridge about 3 km southwest of Gas Rocks at the southern shore of Becharof Lake and called West Maar in this paper.\r\n   \"Poor weather conditions prevented observations on March 31 and April 1, but at 11:00 AST, April 2, a commercial airline pilot observed a 3000-m-high ash plume in the vicinity of Gas Rocks.  A new vent, about 60 m in diameter and located 600 m east of the original vent at about the same elevation, was discovered by an FAA pilot at 17:30 AST; the original vent had partially filled with water and was quiescent.  The new vent was ringed by about seven tephra layers which were thickest on the NNE side of the crater rim.\r\n   \"Reports indicate that the second crater, here called East Maar, had increased in diameter to about 100 m by 10:00 AST, April 3.  At 14:30 AST Alaska Department of Fish and Game (ADFG) personnel photographed a yellowish-orange pool of lava at the bottom of the second crater.  Another bush pilot observed that incandescent material was thrown up to 30 m above the lava pool and that large boulders, up to 1 m and more in diameter, were ejected to a height of 300 m.\r\n   \"On April 4 the weather was poor and it snowed.  In the late morning hours of April 5 an ash cloud up to 4000 m high reached King Salmon, 95 km to the north, where trace amounts of ash accumulated through mid-afternoon.  At 16:30 AST, a spectacular eruption from East Maar was witnessed by ADFG personnel during a helicopter flight near Gas Rocks.  The eruption cloud was initially of a white color, probably rich in steam and poor in solids, a phase which was followed by vigorous ejection of ash and rock debris, culminating in a mushroom-shaped cloud.  The column was approximately 500 m in diameter near its base and reached a height of 3000 m before billowing out.  This eruption was followed by a series of smaller phreatomagmatic explosions.  Many of them had a companion ground wave (base surge?) of gas and tephra which appeared to be directed laterally down a trough leading to the WNW away from the crater.  During the day wind-blown air fall ejecta was dispersed principally to the northwest and north.\r\n   \"By mid-afternoon on April 6 fresh magma had apparently drained from the East Maar and the activity had decreased to steaming, with vapor plumes reaching heights of 1000 m.  This milder activity allowed clearer examination of the East Maar at this stage of its development.  Well-bedded tephra layers, amounting to a total thickness of several meters, surrounded the crater which was conically shaped but skewed, having a nearly vertical south-southeastern wall.  The deepest part of the crater, and also the source of the initial eruptive activity, was at the base of this wall.  Activity increased significantly by early evening when heavy steam and ash laden phreatomagmatic clouds were periodically ejected from East Maar.\r\n   \"Magma had returned to the crater by 09:30 AST, April 7.  During a University of Alaska (UA) overflight, an orange-red lava pool, about 20-30 m in diameter, was observed at the bottom of East Maar.  Incandescent material was again thrown up to a height of about 30 m above the magma pool.  Turbulent dark grey ash laden clouds were periodically (every 5 minutes) ejected from a second vent located northwest of the first vent but still within East Maar, with plumes rising to 1500 m.  The quiet intervals were characterized by intense steaming.  The source of the steam appeared to have been subsurface groundwater coming into contact with magma.  * * *  The height of the magma level within the crater was variable: during one 15-minute period, the magma completely drained from the crater, an ash explosion occurred, then the magma returned to its previous level, about 50-60 m below the southern rim of the crater. * * * No further eruptions were reported until the early morning hours of April 9, when a fisherman saw violent explosions from a distance of 30 km.  These explosions marked the end of the eruption and subsequent activity was confined to steaming and degassing.\"\r\n   Kienle and others (1980) also estimate the total volume of erupted material: \"A total bulk volume of 26x10^6 cubic m is probably an underestimate for the deposits within a 5-km radius of the maars.  The volume of non-juvenile ejecta should be approximately that of the craters.  East Maar is estimated to have a crater volume of 4x10^6 cubic m and that of West Maar is 0.25x10^6 cubic m.  The dome in East Maar above the crater floor has a volume of 0.9x10^6 cubic m.  The total volume of the ejecta represents perhaps 10x10^6 cubic m of dense rock which is substantially greater than the combined crater volume, 4.3x10^6 cubic m.  The excess volume, 5.7x10^6 cubic m of dense rock, is mostly accounted for by that of juvenile airfall material.\"\r\n   Self and others (1980) provide more detailed estimates of the volumes of the erupted juvenile material: \"The volume of the juvenile 'strombolian' deposit plus a rough estimate of the juvenile component of the other deposits gives a dense rock estimate of the order of 0.5x10^6 cubic m.  The basalt lava flow extruded onto the floor of East Maar contains about 1x10^6 cubic m of dense rock.  Hence, about 1.5 x10^6 cubic m were ejected in 11 days activity.  For the lava flow alone a very slow extrusion rate of 1.8 cubic m s^-1 is indicated using 47 hours as the duration of the 'strombolian' phase.","StartYear":1977,"StartMonth":3,"StartDay":30,"StartTime":"04:00:00","StartQualifier":null,"StartQualifierUnit":"","EndYear":1977,"EndMonth":4,"EndDay":9,"EndTime":"04:00:00","EndQualifier":4,"EndQualifierUnit":"Hours","Volcano":"Ukinrek Maars","ParentVolcano":"Ukinrek Maars","VolcanoID":"ak296","ParentVolcanoID":"ak296"},{"ID":469,"Name":"Martin 1978","Description":"   The Bulletin of Volcanic Eruptions (1980) noted that during 1978: \"This volcano continues to actively steam from its summit crater, and is the most conspicuous steamer in the Katmai region.  The steam appears to rise from numerous fumaroles circling the crater rim.\"  This activity does not constitute a volcanic eruption.","StartYear":1978,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Martin","ParentVolcano":"Martin","VolcanoID":"ak189","ParentVolcanoID":"ak189"},{"ID":483,"Name":"Mageik 1978","Description":"   The Bulletin of Volcanic Eruptions (1980) notes that in 1978: \"Mageik also steams profusely from its crater.\" (Communications from D.C. Shackelford).\"  This steaming does not constitute a volcanic eruption.","StartYear":1978,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mageik","ParentVolcano":"Mageik","VolcanoID":"ak187","ParentVolcanoID":"ak187"},{"ID":277,"Name":"Westdahl 1978/2","Description":"   Around 1:15 pm on February 4, 1978, Clark (1978) observed \"great billowing clouds of steam with a drifting black backdrop that suggested falling ash. * * * This was accompanied by lightning, thunder and the smell of sulphur.  * * * By 4:00 pm the cloud had become much broader and dark * * * and Clark observed 'swaths of melting snow coming down the hillside.'  By 4:30 pm the ash was thick at Scotch Cap.  At 6:45 pm Clark 'experienced hail; small stones.  The stones are dark.  The ash has actually been seeding the clouds!  We have noticed small bits of cinder from the cores of the hailstones.'  At 7:35 pm a foot of ash had built up.  At 11:35 pm lightning continued, and appeared red.  Hail and cinder storms continued on and off at Scotch Cap, along with lightning and thunder, until the afternoon of February 5, when the cloud traveled to the southwest.  Clark also reports, on February 6, that the road from Scotch Cap to Cape Serichef was washed out, leaving a 30 foot drop off, at least 100 yards across.\r\n   From Krafft and others (1980): The U.S. Coast Guard reported on 6 February that ash, accompanied by a sulfur odor, was falling on a station located at the foot of Westdahl.  Lightning was observed above the summit, accompanied by thunder and rumbling.  Reeve Aleutian Airways personnel report an ash cloud rising to 8,000 -10,000 m altitude, including some large blocks visible above the 3000 m cloud layer.  Snow contaminated by dark ash fell on the freight vessel UNITED SPIRT between 12:00 and about midnight on 7 February, as it steamed from 48.8 degrees N, 152.5 degrees W to 49.2 degrees N, 156.3 degrees W, about 1000 km SE of Westdahl.  A plume was visible in a satellite image taken at 1129 on 9 February.  After the 9th, activity declined to steaming.  The new crater formed by the February eruption is about 1.5 km in diameter and 0.5 km deep, located at about 1450 m elevation.  Its upper portion cuts through glacial ice, which reaches a thickness of 200 m on the N rim.  The bottom of the vertical-walled crater is filled with blocks, ash, ice, and talus.  A lahar deposit, originating on the WSW flank of the new crater, extends down the glacier on Westdahl's flank to the sea, cutting the road from Cape Sarichef to Scotch Cap.  The thickness of the upper portion of the deposit averages about 50 cm, increasing to 1-3 m near the lower end (Data from: SEAN Bulletin, vol. 3, n. 1, p. 7, n.2, p. 3-6, n. 9, p. 9-11).\"","StartYear":1978,"StartMonth":2,"StartDay":4,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1978,"EndMonth":2,"EndDay":9,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Westdahl","ParentVolcano":"Westdahl","VolcanoID":"ak322","ParentVolcanoID":"ak322"},{"ID":381,"Name":"Shishaldin 1978/2","Description":"   From Smithsonian Institution (1978): \"A NOAA satellite image on 8 February at 1835 shows simultaneous 60-km plumes emerging from the summits of Shishaldin and Westdahl, about 50 km apart. No plume from Shishaldin is visible in images taken 8 hours earlier and 16 hours later. No ashfall at Shishaldin can be seen in the latter image, but resolution is only 0.9 km and a light or moderate ashfall would probably not be visible.\"  See the Smithsonian website for figures of the satellite images: http://www.volcano.si.edu/world/volcano.cfm?vnum=1101-36-\u0026volpage=var\u0026VErupt=Y\u0026VSources=Y\u0026VRep=Y\u0026VWeekly=Y","StartYear":1978,"StartMonth":2,"StartDay":8,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":255,"Name":"Akutan 1978/9","Description":"   From Compton and others (1980), describing activity at Akutan beginning in late September, 1978 and ending in October, 1978: \"Akutan began to erupt in late September, 1978.  Airline pilots reported incandescent fragments, some 'as big as a car' rising about 100 m above the crater.  The U.S. Coast Guard Cutter Morgenthau passed N of Akutan during the evening of 6 October.  Crew members observed incandescent tephra ejection from the summit and glow reflecting upward onto an eruption column.  A deep red glow about 1 km long which appeared to be a lava flow, moved down the slopes of the volcano.\"","StartYear":1978,"StartMonth":9,"StartDay":21,"StartTime":null,"StartQualifier":10,"StartQualifierUnit":"Days","EndYear":1978,"EndMonth":10,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":429,"Name":"Iliamna 1978/11","Description":"   From Proffett and others (1980): \"A brief steam eruption from Iliamna began at about 10:50 (local time) on 7 November, 1978.  Puffs of steam, ejected every 1-5 minutes, rose an estimated 3 km above the summit.  No ash was visible in the steam puffs.  The activity ended at about 13:30.  Iliamna's last reported activity occurred 1952-53.\r\n   \"A U.S. Geological Survey seismic station 20 km NNE of Iliamna recorded no unusual seismicity.\"","StartYear":1978,"StartMonth":11,"StartDay":7,"StartTime":"10:50:00","StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":279,"Name":"Westdahl 1979/2","Description":"   From Pamenter and Kienle (1981): \"Ash cloud about 8 km high.  \"A cloud apparently erupted from Westdahl was present on NOAA weather satellite imagery for more than 30 hours on 8 and 9 February.  The cloud was first observed on an infrared image taken at 03:52 on 8 February, about 17 hours after the previous image, on which no eruption cloud could be seen.  It occurred on 08:42 and 10:37 (infrared) but was not present at 19:58 on the 9th of 09:52 on the 10th.  The cloud was no more than 50 km in longest dimension on any of the images, nor was it elongated into a typical volcanic plume.  The height of the cloud was calculated separately from infrared and visual images taken at 09:26 on 8 February.  Analysis of the infrared image gives a temperature of -53 degrees C at the top of the cloud, corresponding to an altitude of slightly more than 8 km.  On the visual image, measurements of the shadow cast on the weather cloud deck by the volcanic cloud results in an estimated altitude of 7.7 +/- 1 km (Data from SEAN Bulletin, vol. 4, p. 2-3, 1979).\"","StartYear":1979,"StartMonth":2,"StartDay":8,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1979,"EndMonth":2,"EndDay":9,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Westdahl","ParentVolcano":"Westdahl","VolcanoID":"ak322","ParentVolcanoID":"ak322"},{"ID":382,"Name":"Shishaldin 1979/2","Description":"   From Smithsonian Institution (1979): \"Peninsula Airways pilots reported unusually strong ash emission during overflights on 14 or 15, and 27 February.  Ashfall, usually confined to the summit area, was occurring on the upper half of the volcano.\"","StartYear":1979,"StartMonth":2,"StartDay":14,"StartTime":null,"StartQualifier":1,"StartQualifierUnit":"Days","EndYear":1979,"EndMonth":2,"EndDay":27,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":218,"Name":"Pavlof 1980/3","Description":"   Jacob and Hauksson (1983) report a \"period of probable weak steam and ash emissions.  Explosion earthquakes recorded\" between March 30 - May 28, 1980.","StartYear":1980,"StartMonth":3,"StartDay":30,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1980,"EndMonth":5,"EndDay":28,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":150,"Name":"Makushin 1980/5","Description":"   From Shackleford (1982): \"Observations in early July 1980 at Makushin by personnel from Lamont-Doherty Geological Observatory found a new explosion crater on the central cone within the caldera, some 60 m below the cone's summit.  From this new vent tephra (presumably lithic in nature) extended in streaks on the snow's surface to the southeast.  Some of the ejected blocks created impact craters 30-60 m from the crater.  This minor explosive event was not witnessed, but obviously took place only shortly before the date of observation.  It certainly took place within the last year, but Spring 1980 is deemed a likely date for this event.  Otherwise, observations in July 1980 found 10 vents liberating steam and H2S on the summit of the central cone.\"\r\n   From Smithsonian Institution (1980): \"On 8 July, J. Hauptmann, G. Gunther, and R. [Steuer] visited a seismic station on the E flank and overflew the summit. More than ten roughly circular vents emitted vapor from the summit area, a flat region about 100 m across. The largest vent was about 30 m in diameter, and others were around 10 m across. An H2S odor was detected, but no ash or incandescent material was observed.\r\n   \"About 60 m below the summit on the S flank, an explosion vent had recently ejected tephra ranging in size from ash to blocks, deposited in streaks aligned roughly toward the SE. Some impact craters were present in the deposit area, which extended 30-60 m from the vent.\"","StartYear":1980,"StartMonth":5,"StartDay":null,"StartTime":null,"StartQualifier":2,"StartQualifierUnit":"Months","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":217,"Name":"Pavlof 1980/7","Description":"   From Smithsonian Institution (1980): \"07/80 (SEAN 05:07) Steam and a little ash\r\n   \"Pavlof was emitting steam when viewed by J. Davies on 3 July. A few days later, according to second-hand reports, ash was present in the steam column.\"","StartYear":1980,"StartMonth":7,"StartDay":3,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":256,"Name":"Akutan 1980/7","Description":"   From Shackelford (1982): \"Akutan's central cone was observed to be in light eruption in July 1980.  Observations on 3 July showed no eruptive activity.  However, observers noted on 8 July a plume of steam and dark brownish gray ash rising over the volcano's central cone, to perhaps 0.5 -1.0 km above the crater.  No glow was visible.  Also, the July observations included the discovery of a fresh-looking lava flow of small dimensions that had moved through the breach in the caldera wall on the NW.\"","StartYear":1980,"StartMonth":7,"StartDay":8,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":26,"Name":"Gareloi 1980/8","Description":"   Coombs and others (2008) summarize the 1980 eruption: \"On August 8, the crew of a Northwest Orient Airlines plane spotted a plume of ash that rose 35,000-40,000 ft above sea level (Anchorage Times, August 16, 1980, p. A3). David Evans of the USGS reported earthquakes whose epicenters were west of the Adak seismic network on August 8 and 9. Ash fall was not reported at Adak. Cloud cover mostly obscured further observations after August 10, although a photograph of the summit from August 13 shows a light-gray plume rising from the North Peak crater [see fig. 9 in original text]. Evans said, 'As far as we know, there was no lava eruption' (Anchorage Times, August 16, 1980, p. A3). On August 10, airborne stratospheric sampling detected ash and elevated sulfate concentrations between 54 degrees N and 60 degrees N and 150 degrees W (about 2,000 km away) at an altitude of 63,000 ft asl (Sedlacek and others, 1981). On the basis of wind direction and NOAA-6 satellite imagery, the plume was a plausible product of the August 8 eruption (Sedlacek and others, 1981). The Smithsonian reported renewed ash emissions to 6 km asl in September 1980.\"","StartYear":1980,"StartMonth":8,"StartDay":7,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1980,"EndMonth":9,"EndDay":17,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Gareloi","ParentVolcano":"Gareloi","VolcanoID":"ak106","ParentVolcanoID":"ak106"},{"ID":216,"Name":"Pavlof 1980/11","Description":"   From Shackleford (1982): \"Pavlof experienced a strong Strombolian eruption in Nov. 1980. There was a very minor ash emission in early July, but the eruption proper began at 10:47 on 8 Nov. with a short burst from the vent high upon the NE flank.  The main eruptive episode began in the pre-dawn hours of 11 Nov., activity waxing throughout the day.  By early evening on the 11th, lava fountaining was rising 300 m over the volcano, while a lava flow advanced down the N flank (flow may be rootless and spatter-fed).  During the night of 11-12 Nov. the vividly incandescent eruption was clearly visible from Cold Bay and Sand Point, and was likened to a big blowtorch in appearance.  Strong activity lasted through 12 Nov., black ash plumes rising to 6 - 11 km above sea level.  The eruption ended in the morning of 13 Nov.  Strong harmonic tremor accompanied the Nov. eruptions.\"\r\n   McNutt (1999) calculates an eruptive volume of 6.1 x10^6 cubic meters (dense rock equivalent) for this eruption.","StartYear":1980,"StartMonth":11,"StartDay":8,"StartTime":"10:47:00","StartQualifier":null,"StartQualifierUnit":"","EndYear":1980,"EndMonth":11,"EndDay":13,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":173,"Name":"Cone A 1981/3","Description":"   From Reeder (1987): \"During the morning of 24 March 1981, pilot Harald Wilson observed a growing ash and steam eruption plume over Okmok Volcano.  Harold was flying his Peninsula Airways, Inc. Navaho from Cold Bay to Dutch Harbor of Unalaska Island.  His initial observation of the eruption plume was about 1000 local time (=GMT -10 h.) when he was about 80 km NNW of Dutch Harbor at a 2,600 m altitude.  The plume of mixed steam and ash had reached an approximate 2,800 m altitude and was still growing.  The visibility was good with a light wind from the ESE and with fairly cloudless sky.  Before landing at Dutch Harbor 20 minutes later, Harold was able to watch the eruption plume grow to about a 5,500 m altitude, which was drifting to the NW.\r\n   \"At 1100 on 24 March, Harold left Dutch Harbor for Nikolski of Umnak Island.  During this flight, Harold flew over Okmok Caldera and circled the cinder cone that had just erupted (Cone A in the SW part of Okmok Caldera, see U.S. Geological Survey Bulletin 1028-L).  The eruption had stopped and only steam was rising out of the cinder cone.  Some ash was still in the air, but most of the plume had dissipated.  A thin but very noticeable layer of black ash was deposited from the eruption on snow to the NW and WNW of the Cone A over the caldera floor as well as beyond.\r\n   \"At 1500 of 24 March, Harold returned to Dutch Harbor from Nikolski.  Only a small steam plume was being emitted from Cone A.  Harold continued to fly to Nikolski about two to four times a week for Peninsula Airways, Inc. until late 1983.  During these trips, Harold has only observed nearly continuous steam emission from Cone A, which is normal activity for this cone.\"","StartYear":1981,"StartMonth":3,"StartDay":24,"StartTime":"10:00:00","StartQualifier":6,"StartQualifierUnit":"Hours","EndYear":1981,"EndMonth":3,"EndDay":24,"EndTime":"11:00:00","EndQualifier":null,"EndQualifierUnit":"","Volcano":"Cone A","ParentVolcano":"Okmok","VolcanoID":"ak56","ParentVolcanoID":"ak206"},{"ID":516,"Name":"Sanford 1981/4","Description":"   An Associated Press story carried by both the LA Times and the New York times reported that a huge rockslide on Mt. Sanford on April 11, 1981, had been previously mistaken for a volcanic eruption.  The text of the story (Associated Press, 1981) is as follows: \"A huge landslide on Mount Sanford was mistaken for a volcanic eruption by nearby residents and airline pilots passing overhead yesterday, a University of Alaska scientist says.  The slide on the mountain's sheer south face exposed layers of old, loose ash that strong updrafts pushed into a huge plume-shaped cloud, Carl Benson, a member of the university's Geophysical Institute, said after flying over the 16,237-foot peak yesterday.  The landslide occurred in a sparsely populated area, and there were no reports of injury or damage.\"","StartYear":1981,"StartMonth":4,"StartDay":11,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Sanford","ParentVolcano":"Sanford","VolcanoID":"ak242","ParentVolcanoID":"ak242"},{"ID":383,"Name":"Shishaldin 1981/9","Description":"   From Smithsonian Institution (1981): \"Activity accompanied some of the eruption at Pavlof (about 150 km ENE) [see 6:9 Pavlof; Pavlof and Shishaldin are in different time zones]. At 1315 on 25 September, NOAA weather satellite imagery revealed plumes emerging from both Shishaldin and Pavlof (Pavlof was also emitting a plume 4 hours earlier when weather clouds had last allowed a clear view of the area). By 1445, Shishaldin's plume had reached an altitude estimated at 6-7.5 km based on cloud top temperatures calculated from infrared imagery. The plume remained evident on the imagery until 1845, drifting E.\r\n   \"However, no activity from Shishaldin accompanied the ejection of a new cloud from Pavlof at 1845. Satellite images next showed a plume from Shishaldin at 0830 the next morning, when plumes from both volcanoes could be seen drifting ESE. On the next image with clear visibility, at 1315, no activity could be seen from Shishaldin. Reports from pilots through this period were very sketchy, but Shishaldin was said to be 'steaming hard.' No unusual activity was observed after 26 September by pilots or on satellite imagery.\"","StartYear":1981,"StartMonth":9,"StartDay":25,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":220,"Name":"Pavlof 1981/9","Description":"   From McNutt and Shackleford (1983): \"About two weeks before this eruption, a seismometer 7.5 km SE of summit began to register occasional harmonic tremor, plus an increase in the size of B-type events.  However, just a few days before the commencement off visible activity, there was a decrease in the number and size of earthquakes recorded.  On 24 Sept. there were no visible signs of unrest at Pavlof.\r\n   \"On 25 September, explosive eruption started possibly at 10:00 local time (= GMT - 9 hr.).  An eruption plume was observed at 10:30.  This plume drifted to the E \u0026 SE.  During the day eruptive activity waxed.  At 15:45 the plume had risen to 9 km a.s.l.  Another major eruptive pulse commenced shortly before 19:45; by 22:15 the new plume top had reached 10.5 km a.s.l.  The strongest activity of the eruption took place on the night of 25-26 Sept.  A boat in Pavlof Bay received 4 cm of ash that night; the ash was medium coarse sand size.  Observations from Pavlof Bay that night noted vividly incandescent, violent Strombolian activity with black ash clouds.\r\n   \"On 26 September, another significant eruption began at ca. 07:00, plume height of 7.5 km a.s.l. noted at 09:30.  Again, local observers reported billowing clouds of black ash and a brightly incandescent eruption column.  By 10:00, the plume had decreased in height to 6 - 7 km a.s.l., and an active lava flow - brightly glowing - was seen on NNW flank, coming from a vent some 100 m below the summit crater.  Waning activity in the afternoon.  During the night of 26-27 Sept. ash fell on Squaw Harbor (Unga Island, 90 km ESE of Pavlof) to, perhaps, a depth of 1 cm.  This ash was fine sand size.\r\n   \"On 27 September, fine ash still fell at Squaw Harbor in the early morning hours.  Ground reports indicate eruptions of black ash and glowing tephra also.  Strong, continuous harmonic tremor ended at 12:20.  However, seismicity (B-type earthquakes) of small magnitude (0-1) remained high for several months afterwards.\r\n   \"This eruption is fairly typical of eruptions observed over the last 10 years at Pavlof.\"\r\n   McNutt, 1987 reports this eruption produced approximately 1.0-1.7x10^7 cubic meters of ash, and 4.7-5.8x10^6 cubic meters of lava as a rootless lava flow of basaltic-andesite composition.\"","StartYear":1981,"StartMonth":9,"StartDay":25,"StartTime":"10:00:00","StartQualifier":null,"StartQualifierUnit":"","EndYear":1981,"EndMonth":9,"EndDay":27,"EndTime":"12:20:00","EndQualifier":null,"EndQualifierUnit":"","Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":27,"Name":"Gareloi 1982/1","Description":"   From Miller and others (1998): \"On January 14, 1982, a magnitude 3.2-3.3 earthquake struck the area; the following day, January 15, a 7-9 km eruption cloud was observed on satellite imagery (Smithsonian Institution, 1982).\" \r\n   Smithsonian Institution (1982), SEAN v. 07, n. 02: \"02/82 (SEAN 07:02) Large plume seen on satellite imagery","StartYear":1982,"StartMonth":1,"StartDay":15,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1982,"EndMonth":1,"EndDay":15,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Gareloi","ParentVolcano":"Gareloi","VolcanoID":"ak106","ParentVolcanoID":"ak106"},{"ID":257,"Name":"Akutan 1982/10","Description":"   From Reeder (1986): \"Steam has been emitted continuously from the large cinder cone within the Akutan summit caldera since its last July, 1980 eruption * * *.  Then, sometime during the first part of October 1982 very light ash falls from this cone occurred in Akutan village, which is located about 12 kms to the east.  For example, Charles McGlashan of Akutan noticed during the first part of October 1982 ash on his white canvas tent, which he had originally erected at the village in August.  By the end of October, the tent was light grey in color because of the light ash falls.  Larry Mensoff of Akutan noticed a small ash fall that occurred in Akutan village in November.  Then, on the morning of 18 +/- December, 1982, the community has a light but very noticeable layer of ash that had fallen the previous night over snow (sources of information: Paul Mahoney of Dutch Harbor, and others from Akutan village).  The same day, Paul Mahoney left for Dutch Harbor by boat.   \r\n   \"* * * Airpac pilot Dave Henley on 22+/- December noticed fresh ash deposits on the Akutan summit region as well as the healthy emission of steam with some dark smoke from the cinder cone within the Akutan caldera.  On his first flight to Akutan on the 23 +/- December, he again noticed some smoke emissions from the cinder cone. \r\n   \"Paul Mahoney returned to Akutan on the second Airpac flight from Dutch Harbor to Akutan village on 23 +/- December.  This midday flight was also flown by Dave Henley.  Both were in favor of investigating the summit region of Akutan volcano, especially since the weather was clear enough to see Akutan volcano when air-borne from Dutch Harbor.  A smoky haze could be seen above Akutan volcano as they approached and sulfur gases were detected even before they reached the volcano.  They then circled the steaming Akutan cinder cone several times, flying just above (approximately 100 m above) the rim of the Akutan caldera.  Suddenly, the steaming cinder cone started to erupt ash, lapilli, and blocks of rock.  Paul Mahoney took photographs.  Fearing damage to the plane, Dave immediately left the caldera and completed his flight to the village.  Dave estimated, while he was returning to Dutch Harbor about 20 minutes later, that the tephra cloud had reached a height of 2 km above the volcano (an altitude of 3.3 km).  No ash-fall occurred at Akutan village during this particular eruption.\"  \r\n   \"A visit to Akutan volcano was made by J.W. Reeder on 16 January, 1983.  At this time, a small amount of ash was observed on the eastern side of the volcano over 14-15 January snow deposits (EOS, Trans. Amer. Geophy. Union, v. 64, no. 28, p. 451).  Steam was being emitted from the cinder cone.  \r\n   \"After this visit, several similar fresh ash deposits were noted by pilot Dave Henley (Airpac Inc., Dutch Harbor) up into May 1983.  Unfortunately, there is no dated record of these observations.  No 1983 ash falls occurred in the Akutan village, which is located about 12 km east of the cone.  \r\n   \"J.W. Reeder, with the climbing assistance of Scott Kerr from Unalaska and of Mark Larsen from Anchorage, climbed to the summit of the Akutan volcano on July of 1981.  Based on this 1981 observation and on the 16 January, 1983 observation, no new lava flows nor major changes to the steaming cinder cone had occurred during the 1982-83 eruption.\"","StartYear":1982,"StartMonth":10,"StartDay":7,"StartTime":null,"StartQualifier":7,"StartQualifierUnit":"Days","EndYear":1983,"EndMonth":5,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":319,"Name":"Veniaminof 1983/6","Description":"   From Yount and others (1985): \"The more prominent of the two visible intracaldera cones of Mount Veniaminof went into eruption in early June 1983 and continued until early April 1984.\r\n   \"* * * In this recent eruption, Perryville residents first saw puffs of ash on June 2, 1983.  Early manifestations of the Strombolian eruption included a 90-m-wide sector graben and a circular depression (400 m in diameter and approximately 30 m deep) in the glacial-ice surface directly south of the active cone.  By June 9, the 300-m-deep crater of the cone had filled to overflowing with juvenile bombs, blocks, and rising magma, resulting in a lava flow from a low point on the southwest side.  The lava flow and subglacial heating caused rapid melting of the glacial ice on the south side of the active cone.  By July 13, a vertical-walled, bilobate pit measuring approximately 1,300 m in the east-west direction, 400-800 m in the north-south direction, and 60-100 m deep had formed in the ice.  The pit contained a lake of unknown depth and a southward-building lava delta.  A subglacial tunnel in the ice-wall at the east end of the lake indicated drainage eastward along the caldera floor.  Another tunnel, less clearly observed, may have drained from the northwest end of the lake toward a breach of the caldera wall at Cone Glacier.\r\n   \"Ash emission was almost continuous during June and July 1983; occasional plumes were estimated to have been as high as 7,800 m.  During this time, ash blanketed the intracaldera glacier and steam plumes occurred nearly continuously.  The eruption appeared to wane from mid-August to early October, through this may be partly a function of paucity of reports and observations.\r\n   \"Renewed activity was reported in early October.  By this time the ice-pit lake had diminished to a small pond located between the wall of the ice pit and a new lava flow lobe.  The October 1983-March 1984 eruptive phase was characterized by less ash emission and more lava flow activity than the June-August 1983 phase.  A succession of flows from the southwest side of the cone resulted in a continual increase in volume and height of new lava in the ice pit, and the pit enlarged slightly in plan, losing its bilobate shape.  Each flow lobe cooled rapidly due to the 1,800-m elevation and winter winds; snow was observed on lobes approximately a month old. Perryville residents observed incandescent lava fountaining up to an estimated 100 m above the cone on January 23, February 6 and 13, and March 2 and 3, 1984.  Fountaining was intermittent, lasting one-half to one hour and was followed by quiescent periods of at least 45 minutes.  Incandescent glow was last observed March 16, 1984.  From mid-March to late April, activity was limited to continual emission of small steam plumes and rare ash bursts lasting up to two hours.  An observation flight on April 11 revealed that all lava-flow lobes in the pit were dusted with snow.\"\r\n   The Smithsonian Institution Scientific Event Alert Network Bulletin, volume 5, number 1 reports that USGS personnel estimated that approximately 45x10^6 cubic meters of lava filled the ice pit between June, 1983 and January, 1984.","StartYear":1983,"StartMonth":6,"StartDay":2,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1984,"EndMonth":4,"EndDay":17,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Veniaminof","ParentVolcano":"Veniaminof","VolcanoID":"ak301","ParentVolcanoID":"ak301"},{"ID":175,"Name":"Cone A 1983/7","Description":"   From Grey (2003): \"A 100 km long plume was recognized in one NOAA 7 image at 1716 local time on July 8 [1983] (0216 UTM on July 9), but was not seen on images 12 hours earlier or later.  This was apparently only a brief puff of ash and steam, accompanied by sulfurous gases, as reported by Aleutian Air pilot Tom Madsen (Reeder, 1986).\"\r\n   From Reeder (1986), describing what Tom Madsen saw on his flight to Atka from Dutch Harbor on July 8: \"Upon reaching Driftwood Bay, which is about 23 km WNW of Dutch Harbor, Tom could clearly see a hazy yellowish-brown smoke horizon straight west in the Okmok region.  This smoke horizon was at an altitude of about 1,000 m and higher.  The smoke was densest at Okmok, and the smoke horizon extended north across the Bering Sea as far as Tom could see (about 100 km).  Due to thick fog and rain, Tom could not see the extent of the cloud to the south.  Because Tom could not recognize the top altitude of this smoke cloud and because it appeared to extend over a very broad region, he elected to continue his normal route along the Bering Sea side of the Aleutian Island at an altitude of 500 m.  Upon reaching Cape Idak of the most eastern part of Umnak Island, which is about 25 km NE of Okmok caldera, he was beneath the eastern edge of the cloud.  Tom could detect sulfur gases.  The cloud above him had a definite yellow tinge and at a distance was yellowish brown.  He did not reach the other end of the cloud until he reached Inaudak Bay along the central Bering Sea side of Umnak Island, which is about 25 km SW of Okmok caldera and about 50 km SW of Cape Idak.  No damage occurred to the Twin Beechcraft.  Tom continued his normal route to Atka, arriving at about 1100.  He then returned to Dutch Harbor by the same route, leaving Atka at about 1400 and arriving at Dutch Harbor at about 1600.  During this return, he again had the same experience of flying under the Okmok eruption cloud, which started at about Inanudak Bay and ended at Cape Idak.  During Tom's previous 3 years of flying in the Aleutian Islands, he has never had such an experience.\"\r\n   From Reeder (1986): \"On 9 August, J.W. Reeder, while flying with Tom Madsen, made examinations of Okmok caldera.  No new lava flows were recognized within Okmok caldera.  Cinder Cone A, which is located in the SW region of Okmok caldera was teaming and some ash was noticeable over remaining winter-snow up to a 2 km radius from Cone A.  A nearly transparent blueish smoke was also detected drifting to the east from the cone.  J.W. Reeder and Tom Madsen have made several independent observations of the caldera during the previous 3 years.  Cinder Cone A appeared to be similar in physical appearance, except it was steaming and smoking above average.\"","StartYear":1983,"StartMonth":7,"StartDay":8,"StartTime":"09:00:00","StartQualifier":16,"StartQualifierUnit":"Hours","EndYear":1983,"EndMonth":7,"EndDay":8,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Cone A","ParentVolcano":"Okmok","VolcanoID":"ak56","ParentVolcanoID":"ak206"},{"ID":221,"Name":"Pavlof 1983/7","Description":"   From Miller and McNutt (1986): \"An increase in seismic activity was recorded in mid-July 1983.  Seismicity remained at background levels until 11 July.  During the 24-hour period beginning at 1500 on the 11th, 6 explosions were recorded at a Lamont-Doherty seismic monitoring station near the volcano.  The number of recorded events increased to 55 for the same period on 12-13 July, and to 150 on 13-14 and 14-15 July, then decreased to 120 on the 15-16th, 38 on the 16-17th, and 19 on the 17-18th, returning to background after 1500 on 18 July.  During the period of increased seismicity, approximately half of the recorded events were low-frequency events.\r\n   \"At 1549 on 15 July, a thermal infrared image from the NOAA 7 polar orbiting satellite showed a bright spot over Pavlof and an elongate plume extending approximately 150 km to the E.\"","StartYear":1983,"StartMonth":7,"StartDay":11,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1983,"EndMonth":7,"EndDay":18,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":222,"Name":"Pavlof 1983/11","Description":"   From Miller and McNutt (1986): \"Eruptive activity was first observed from Sand Point (about 90 km E of the volcano) late on 14 November and pilots observed tephra columns the next afternoon.  On 19 November a small vapor cloud rose approximately a hundred meters above the vent.  Bad weather prevented observations until 26 November when Pavlof was visible until mid-afternoon from Cold Bay (about 60 km SW of the volcano).  During the morning, a vapor plume containing a little ash rose to 4.5 km altitude.  At intervals of approximately 30 minutes, puffs of dark ash were emitted.  The intervals became shorter, and by 1500 ash emission was nearly continuous.\r\n   \"Through October and early November, a Lamont-Doherty seismic monitoring station near the volcano recorded background levels of 0-40 (usually 0-30) small low-frequency events per day.  A 30-minute burst of volcanic tremor began at 2000 on 4 November, and a 6-minute burst at 1757 on 9 November.  Between 1430 on 11 November and 1100 on 13 November, 15 explosions were recorded.  Several bursts of tremor of 1-2 minute duration occurred between 1700 and 1900, when continuous tremor started.  Its amplitude gradually increased, and tremor began to saturate the seismograph at 1100 on 14 November.  Tremor was strongest between midnight and 1200 on 15 November, and continued to saturate the seismograph until 2100 on 15 November when its amplitude began to decrease.  Tremor remained continuous but at low amplitude between 1300 on 16 November and 1200 on 18 November.  Intermittent low-amplitude tremor and numerous low-frequency (B-type) events recorded after 1200 on 18 November were continuing on 21 November.\r\n   \"Airline pilots last reported eruption clouds from Pavlof at 1400 on 15 December and there have been no eyewitness reports of eruptive activity since then.  Six explosions were recorded between 1600 and 2000 on 15 December by Lamont-Doherty's 5-station seismic net 4.5 - 10 km from the volcano.  One of these stations, about 7.5 km from Pavlof, detected bursts of harmonic tremor 17 December, 1100 - 18 December, 0330; 18 December, 0530 - 0615 and 1040-1110; 20 December, 2200 - 2245; and 21 December, 2035 - 2048.  Seismicity then decreased to the background level of several tens of events per day and remained at that level as of 26 January.\r\n   \"Eruption plumes were observed on 3 images returned 15-17 December from the NOAA 8 polar orbiting satellite.  The images returned at 2101 on the 15th and 1031 on the 17th showed well-defined, relatively dense plumes extending 225 km E and 400 km NE from Pavlof above the weather cloud layer.  A diffuse plume was observed on the image returned at 2108 on 18 December.\r\n   \"No volcanic plumes were observed on other images returned 15-21 December, but heavy weather clouds obscured the area.\"\r\n   McNutt (1985) calculates an estimated lava volume based on photoanalysis and pilot reports as 1.2 - 2.8 x10^6 cubic meters, and an additional 2-8 x10^6 cubic meters of ash.  McNutt (1999) reports a single dense rock equivalent volume of 10.8 x10^6 cubic meters for this eruption.","StartYear":1983,"StartMonth":11,"StartDay":14,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1983,"EndMonth":12,"EndDay":18,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":296,"Name":"Cleveland 1984/7","Description":"   From Reeder (1987): \"Pilot Tom Madsen observed a small ash and steam eruption of Mount Cleveland during one of his numerous flights to Atka of Atka Island from Dutch Harbor of Unalaska Island.  His observation was made at about 1300 local time ( = GMT -9 h.) on 12 July 1984.  The ash and steam plume was drifting to the southeast up to a 2,300 m altitude from a small southeast summit crater of the volcano.  Some steam was also rising from the southeast side of the volcano.  Some hot rock and/or debris had apparently gone down nearly the entire SE side of the volcano.\r\n   \"Tom Madsen has flown in the Aleutians since 1980, and steam emission from the summit region of Mount Cleveland during this time was very common.  Tom has on occasion observed small ash and steam eruptions like this one, but the exact dates of such previous eruptions are unknown.\"","StartYear":1984,"StartMonth":7,"StartDay":12,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1984,"EndMonth":7,"EndDay":12,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":94,"Name":"Amukta 1984/7","Description":"   From Reeder (1987): \"Pilot Tom Madsen observed the emission of voluminous amounts of steam from the summit crater of Amukta volcano of Amukta Island during a return trip from Atka of Atka Island to Dutch Harbor of Unalaska Island.  His observation was made at about 1600 local time on 12 July 1984.  The steam plume completely filled the summit crater, rose to a 1,100 m altitude just above the volcano, and drifted to the SW for at least 4 km at a lower altitude.  Tom Madsen has flown in the Aleutian Islands since 1980 and he has only observed occasional wisps of white steam from this crater before.  This steam activity was considered by Tom to be very anomalous.\"","StartYear":1984,"StartMonth":7,"StartDay":12,"StartTime":"16:00:00","StartQualifier":1,"StartQualifierUnit":"Hours","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Amukta","ParentVolcano":"Amukta","VolcanoID":"ak10","ParentVolcanoID":"ak10"},{"ID":320,"Name":"Veniaminof 1984/11","Description":"   From Smithsonian Institution (1984): \"Eruptive activity resumed on 29 November [1984]. At about 0400, Perryville residents were awakened by rumbling noises from the volcano. By 0800, a black ash cloud was rising to about 3.5-4 km altitude. At 1000, a second plume rose to about 4 km, followed by smaller bursts that were occurring at approximately 5-minute intervals as of about 1020. Pilots reported an ash plume to about 4.5 km altitude at 1045, very little activity at 1100, and another ash plume to about 5.4 km at 1115. No incandescent material was observed from Perryville or by the pilots.\r\n   \"A pilot who flew over the volcano on the morning of 5 December reported a white vapor plume, containing only a small amount of ash, rising from two small pits on the E side of the previously active cone. One of the pits was steaming more vigorously than the other, and a brownish haze drifted downwind from the volcano. He observed no incandescent material or recent lava extrusions. On 6 December, Perryville residents observed large vapor plumes of varying intensity that contained very minor amounts of ash. They saw no incandescent material, and had heard no rumbling noises during the previous several days. On 7-8 December the volcano was obscured by weather clouds; however, small intermittent vapor plumes with no ash were observed from Perryville on the 9th. No incandescent material was seen. On the 10th and 11th, the volcano was not visible from Perryville.\"","StartYear":1984,"StartMonth":11,"StartDay":29,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1984,"EndMonth":12,"EndDay":9,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Veniaminof","ParentVolcano":"Veniaminof","VolcanoID":"ak301","ParentVolcanoID":"ak301"},{"ID":297,"Name":"Cleveland 1985/12","Description":"   From Reeder (1988): \"About 1200 local time (= GMT - 11) on 10 December 1985, pilot Tom Madsen observed an anomalous 0.5 + km high eruption column over Mount Cleveland volcano from the ground at Nikolski, Umnak Island, which is about 65 km ENE of the volcano.  The top of this vertical column had drifted to the north by at least 0.5 km.  Because of the pronounced white color of this eruption cloud, it probably consisted principally of steam with only minor amounts of ash.  As based on observations by Tom Madsen, Mount Cleveland volcano has been emitting some steam with minor amounts of ash fairly continuously since 1980, which is the time he began to fly in the Aleutian Islands.  Small steam with some ash eruptions are fairly common for this volcano (see Bulletin of Volcanic Eruptions No. 24 for an example) but this one was the largest he has seen.\"","StartYear":1985,"StartMonth":12,"StartDay":10,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":258,"Name":"Akutan 1986/2","Description":"   From Reeder (1989): \"Intermittent steam-blast eruptions with or without ash occurred from the tephra cone inside the summit caldera of Akutan volcano during 3 February through 8 May 1986.  Intermittent tephra eruptions occurred from this cone during 1 June through 14 June 1986.\"  See original text for chart and details of observed activity.\r\n   Miller (1987) gives this summary of the activity: \"The eruption was characterized by sporadic ejection of ash to heights of 15,000 feet from a 4,275-foot-high intracaldera cone.  No ashfalls were recorded in the nearby villages of Dutch Harbor and Akutan, and the eruption was not considered a hazard.\"","StartYear":1986,"StartMonth":2,"StartDay":3,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1986,"EndMonth":6,"EndDay":14,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":384,"Name":"Shishaldin 1986/3","Description":"   From Reeder (1989): \"Steam-blast eruptive activity with and without ash occurred intermittently during 19 March 1986 up into 1987.\"  Details of the 1986 eruption are in Reeder, 1989; details of the 1987 eruption are in Reeder, 1990.\r\n   From Reeder (1989): \"At about 1325LT 19 march 1986, James Dickson, a resident of Unlaska, observed, while on a MarkAir Inc. flight from Dutch Harbor to Anchorage, yellow to brown wisp rise about 90 m above the summit crater of Shishaldin Volcano.  Previous emissions strung out as a nearly transparent brown horizon toward the SW, which could be seen for over 50 km.\r\n   \"Captain Jerry Chisum of MarkAir Inc., who flies the Dutch Harbor to Anchorage route often, observed another ash horizon from the volcano on 28 March.  Based on Jerry's observations, Shishaldin normally emits intermittenly only minor amounts of steam from its summit crater.\r\n   \"Several pilots observed anomalous steam and ash emission activity from the summit crater of Shishaldin Volcano on the 5 through 8 May 1986.\r\n   \"At 1400LT 5 May, pilot Harold Wilson of Peninsula Airways Inc. observed continuous and very strong steam and ash emission from the summit crater that was rising 500 m above the volcano and trailing as far as one could see to the WNW over the Bering Sea.  Harold observed some hot rock with debris avalanching from the crater rim.\r\n   \"Captain Jerry Chisum observed at 1320LT 6 May an impressive steam plume with some ash that was continuously rising at a 45 degree angle to the 3,400 m altitude, and it had drifted then horizontally for 25 km.  Captain Lee Goch of Reeve Aleutian Airways Inc. at 1350LT observed a steam plume with traces of ash.  The slightly gray plume was drifting to the NE for at least 40 km at a 3,600 m altitude.\r\n   \"Pilot Thomas Madsen, President of Aleutian Air Ltd. at Dutch Harbor, observed the plume at 1300LT 7 May.  The plume trailed at about 3,600 m altitude to the S for at least 130 km.  The plume had a definite gray tone with some streaks of dark ash.  Captain Jerry Chisum also observed the impressive plume at 1320LT, at which time large puffs were occurring from the crater about every 20 minutes.\r\n   \"Less intense activity was reported by both Tom and Lee on the 8 May.  On the same day, Tom still detected a grayish plume that drifted for a considerable distance to the E.\"\r\n   From the 10th of May until the end of June, 1986, only steam plumes were observed at Shishaldin.  Minor amounts of ash were observed on June 19th, and \"smoke\" throughout July.\r\n   Reeder (1989) continues: \"On the 20 August 1986, Jason Currier, a resident of Unalaska, observed at 'close range' traces of ash along with voluminous amounts of steam being emitted from the volcano at 1345LT, while he was on a MarkAir Inc. flight from Dutch Harbor to Anchorage.\"  Another steam plume was observed on 21 August.\r\n   Reeder (1989), continued: \"On the 2 October 1986, Captain Jerry Chisum observed anomalous steam-blast activity with minor amounts of ash.  Stephanie Madsen of Aleutian Air Ltd. of Dutch Harbor was on Jerry's flight to Dutch Harbor, and she observed at about 1145LT the Shishaldin steam plume with minor amounts of 'smoke' trailed to the SW for at least 15 km.\r\n  \"On the 3 October 1986, Captain Harold Blake of Reeve Aleutian Airways Inc. observed at 1330LT anomalous steam puffs with minor amounts of ash from the Shishaldin summit crater.\"  The steam plume drifted about 400 m above the summit crater, and puffs lasted about 3 minutes each, and were 3 minutes apart.  Steam-blasts were observed on 4 October, and minor amounts of ash were visible on the flanks. Steam plumes were also observed on 8, 10, and 27 October.  On 17 November, a steam plume with an ash haze was observed.  Steam plumes were observed periodically throughout the end of the year.\r\n   Activity continued into 1987.  Steam plumes were common at Shishaldin from January 1987 until March, 1987.  Ash was observed on 15 February, and possibly on 26 February.  Reeder (1990): \"Marsha Brown observed from Cold Bay at 1600LT 15 February a large dark (apparent ash rich) plume that rose at least 600 m above the volcano and that then was drifting an unknown distance ENE toward Cold Bay.  The plume did not exist two hours earlier.  The plume was dark gray while other lower altitude nearby clouds were white to very light gray.  She watched the plume until darkness at 1830LT.\r\n   \"At 0925LT 26 February, Theresa Dubber at Cold Bay observed a 300 m high steam plume above the volcano that was drifting to the SW.  Pilot Tom Madsen observed this plume at close range and thought he could recognize some traces of ash in the plume.\"","StartYear":1986,"StartMonth":3,"StartDay":19,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1987,"EndMonth":3,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":411,"Name":"Augustine 1986/3","Description":"   From Swanson and Kienle (1988): \"Precursory seismic activity was first detected in July 1985, 8 months prior to the 1986 eruption.  A sharp increase in seismicity in March 1986 led to speculation about a possible eruption (Kienle, 1986).  A several-order-of-magnitude increase in seismic event counts on the morning of March 26 heralded the eruption that began on the morning of March 27.  A short-term forecast of the eruption was made on the afternoon of March 26 (Kienle and others, 1986).\r\n   \"The initial phase of the eruption involved explosive removal of a portion of the 1976 dome and formed a small (about 100 m in diameter) vent on the southwest flank of the dome (Miller and others, 1987; Yount and Miller, 1987).  Numerous pyroclastic flows were observed during the 103 hours of this first eruptive phase, and eruption columns reached heights in excess of 12,000 m (Yount and others, 1987).  Pyroclastic flows were directed through the breach in the north side of the crater and spread out on the lower flanks of the volcano.  Some of these pyroclastic flows reached the sea to the west and east of Burr Point, and ash cloud surges continued for some distance offshore.\r\n   \"Prevailing winds on March 27 and 28 were from the southwest and spread ash throughout Cook Inlet.  Later on March 28, the winds shifted to the west and finally to the north on March 30 and 31.  Ash was thus scattered over populated areas in Cook Inlet only during the early stages of the eruption, but the dust lingered in the air over Cook Inlet, including Anchorage, until March 31.\r\n   \"Lava was extruded during the second eruptive phase from April 23 to 28.  A short blocky lava flow issued from the base of the 1976 dome remnant.  Pyroclastic flows descended from the growing dome, but none of them reached the sea.\r\n   \"* * * A period of accelerated dome growth between August 30 and 31, 1986, resulted in an increase of pyroclastic flow activity.  Flows moved down the north flank of the volcano for distances up to 2.2 km from the source (Kienle, 1986).  Eruption clouds rose 1000 to 2000 m above the volcano during this episode.  None of the pyroclastic flows reached the sea.\r\n   \"High-silica, two-pyroxene andesite, similar to that produced in previous Mount St. Augustine eruptions was also erupted in 1986 (Swanson and others, 1986; Harris and others, 1987).  Groundmass glass in the 1986 andesites is rhyolitic in composition, as in past eruptions, and this is one factor in the explosive character of the eruption.  Distribution of eruptive products and volumes of material erupted in 1986 was also similar to other historic eruptions.\r\n   \"Pyroclastic flow deposits were restricted to the north flank of the volcano, the result of funneling through the breach in the north side of the crater.  Lahars composed of reworked air fall deposits form a circular pattern around the upper part of the cone.  On the south flank, lahars descended to about 300 m above sea level.\r\n   \"The new dome occupies the central part of the volcano and a small lava flow extends just a few hundred meters from the dome.  A new 50-m-high spine was extruded during the August phase of renewed dome growth.  Since then, a large section of the 1986 dome has collapsed and has formed a debris avalanche deposit on the upper northern slope of the volcano.\r\n   \"Incandescent vents were discovered on August 28, 1987, at the southern base of the spine, with maximum fumarole temperature of 88 degrees C (R. Symonds, personal communication, 1987).\r\n   \"A new topographic map of Augustine Island was prepared by North Pacific Aerial Surveys for the U.S. Geological Survey from aerial photography taken on September 9, 1986, using geodetic control points surveyed by University of Alaska and U.S. Geological Survey personnel on June 6, 1986 (J. Power, personal communication, 1986).  The map shows that the 1986 dome had reached a height of 1252 m by September 9, 1986.  Thus the dome gained about 26 m in elevation between 1976 and 1986.  The highest point of the volcano is the south peak, which remained unchanged at 1252 m.  More changes in dome height could have occurred since then, but the dome has not yet been resurveyed.  The total expanded volume of the 1986 pyroclastic flow deposits on Augustine Island is estimated to be close to the 1976 pyroclastic flow volume of about 0.05 cubic km, but could be a little larger.\"\r\n   The April edition of the Scientific Event Alert Network Bulletin (v. 11, n. 04) gives an inflated material estimate of 0.11 cubic km for the March 31 pyroclastic flow, and an estimate volume for the dome (as of May 6) of 0.06 cubic km.","StartYear":1986,"StartMonth":3,"StartDay":27,"StartTime":"00:00:00","StartQualifier":null,"StartQualifierUnit":"","EndYear":1986,"EndMonth":9,"EndDay":10,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":223,"Name":"Pavlof 1986/4","Description":"   From McNutt and others (1991): \"The visual observations of the 1986 eruptions, both aerial and on the ground, provide information generally lacking from previous historic eruptions.  The physical characteristics of of the 1986 eruption are probably similar to other historic summit eruptions, although the 1986 activity was more explosive and of longer duration.\r\n   \"The 1986 activity was chiefly Strombolian, characterized by sporadic emissions of dark ash to heights of up to 5 km; one exceptionally strong (probably Vulcanian) eruptive event sent an ash column to over 15 km on 18-19 April.  The initial phase of the eruption appears to have involved the summit vent on the north side of the volcano which has been the site of all Pavlof eruptions since the mid-1960s.  This eruptive phase lasted from 16 to 26 April and included a hot rootless agglutinate flow that extended down the northwest flank of the volcano.  The deposit was actively degassing steam along its entire length in late June.  It had an estimated volume of about 4x10^6 cubic meters and, at an elevation of 760 meters, was 20-30 meters thick and 40-50 meters wide.  The deposit was clast-supported and fines-depleted, consisting entirely of glassy, slightly vesicular andesitic basalt (SiO2 = 53.5%) bombs and irregular masses of spatter with a maximum diameter of about 1.2 meters.  It was probably emplaced during the initial and relatively violent vent-clearing phases of the eruption on 16-28 April.  Associated hot lahars caused melting of snow and ice and extensive flooding in the Cathedral River drainage north of the volcano.  Heavy ash fall occurred north and west of the volcano during the April activity; 2-3 mm of ash fell on the nearby communities of Cold Bay, 35 km to the west, and King Cove, 48 km to the southwest, but caused no damage.\r\n   \"Eruptive activity began again in late May and was highlighted by sporadic, but vigorous Strombolian eruptive activity and by the formation of a new vent high on the east flank of the volcano.  Comparison of aerial photography indicated that this is the first major change in the vent geometry of Pavlof since the early 1960s.  The period of activity was characterized by repeated small bursts of ash and cinder to a few hundred meters above the vent and spatter tossed a few tens of meters all accompanied by explosive, thunderlike reports.  The explosions characterizing the Strombolian eruption occurred at intervals of 5-15 seconds during the half dozen times the new vent was observed between 14 June and 30 June, suggesting a moderately rapid rate of magma rise in the conduit.  Only minor ash emission was observed associated with the explosive ejection of incandescent bombs from the new vent.  Activity from the old north vent during this time consisted of steam emission with little or no ash.\r\n   \"Close airborne examination of the new vent on 15 June revealed that a steep-sided, asymmetrical spatter rampart, 50-75 m across, had been constructed on the east, or downslope, side of the vent.  A steep chute, directly below the spatter rampart, contained a steaming, rootless rubble flow.  Further down the volcano at an elevation of about 750 m, this flow was about 100 m wide and consisted of bread-crust-like bombs and irregular masses of lava and spatter, up to 4 m in diameter, in an ash-rich, moderately inflated matrix (in contrast to the flow on the northwest flank).  It was actively degassing, exhibiting abundant steam fumaroles and occasional phreatic eruptions.  The flow, with an estimated volume of 3.8 x 10^6 cubic meters, also generated a number of mudflows that continued downslope to about 600 m where the rubble flow-mudflow complex widened into three broad lobes.  Below this elevation, debris-laden water from the flows was contained in a steep-sided small canyon.\r\n   \"The nature of the material in the flow at this elevation and the physical characteristics of the spatter rampart at the vent strongly suggest that much of the lower part of the flow may have resulted from similar pyroclastic flow activity following partial collapse of the oversteepened spatter rampart.  Throughout the course of the eruption, the steep spatter rampart may have periodically become unstable and collapsed, either in whole or part, forming hot, disaggregated pyroclastic flows cascading down the chute.  Where ice and snow were overrun by the hot debris, mudflows were generated that continued to travel down and fan out on the volcano's lower slopes.  In support of this hypothesis, a pyroclastic flow was observed on 19 June moving down the same chute from about 1400 m elevation to about 900 m; the upper 1100 m of the volcano was cloud-covered at this time.\r\n   \"An alternative scenario is that the pyroclastic flow observed on 19 June resulted from a 'boil-over' of the magma column at the vent following a larger-than-usual explosion.  Although no seismic evidence for such an explosion was observed, the obscuring cloud cover prevents an exact explanation for the origin o fthe observed pyroclastic flow.\r\n   \"The April-August eruption is similar to, but somewhat stronger than most of the other Pavlof eruptions of this century (Simkin and others, 1981; McNutt 1987a) in terms of its Strombolian character.  The duration of the eruption, as indicated by lava fountain activity and spatter ejection, however, appeared to be much longer than for most modern eruptions.  This eruption also altered the physiography of the summit area by forming a new vent.  In contrast to most recent eruptions (i.e., 1973-1983) that occurred in the fall of the year, the 1986 eruption was concentrated in the spring and summer.\"\r\n  McNutt and others (1991) also give detailed information about the seismological data collected during this eruption.  \r\n  Information on the continuing volcanic activity in 1987 and 1988 is in other sources.  From Reeder (1990, pg. 53): \"Numerous observations of tephra and steam emissions were made during most of 1987 from NE and SE near summit vents and less from a NE flank vent.  Lava flows occurred on both the NE flank and the SE flank of the volcano from the summit vents down to at least a 1,000 m a.s.l. elevation in January and February, form the NE summit vent in May and June, and again from both summit vents in August.\"  Please see the rest of this text for detailed eruption observations in 1987.\r\n   From Reeder (1991): \"Pavlof volcano has been fairly active during 1986 and 1987 with tephra and lava emissions occurring form several summit and flank vents.  During 1988, eruptive activity was restricted to only small tephra and steam emissions from NE near summit vent up through August 13, except for one minor steam emission from a NE flank vent on March 2.  Since August 13, 1988, no eruptive activity was observed for the rest of the year.\"  Please see the rest of this text for detailed eruption observations in 1988.","StartYear":1986,"StartMonth":4,"StartDay":16,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1988,"EndMonth":8,"EndDay":13,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":298,"Name":"Cleveland 1986/4","Description":"   From Reeder (1989): \"On 28 April 1986, pilot Thomas Madsen, President of Aleutian Air Ltd. at Dutch Harbor, observed an eruption plume from the summit of Mount Cleveland.  His flight was from Dutch Harbor on Unalaska Island to Atka on Atka Island.  He initially saw the eruption plume at about 1220 LT at a distance of 190 km as he was approaching Mount Cleveland from the E.  Tom estimated that the grayish white plume reached an altitude of about 2,900 m, about 1,200 m above the summit, and it trailed off for kilometers to the SSE.  Tom had to fly at s 2,300 m altitude when he reached Mount Cleveland because of a 2,100 m altitude cloud layer, which prevented him from getting a good look at the flanks of the erupting volcano.  The light gray plume had definite dark streaks and swirls of ash.  Passengers including Dutch Harbor residents Mary Belle and Glen Fretwell of Peninsula Airways Inc. flight, which passed the volcano at about 1345 LT, reported a 1,000 m high white to gray eruption plume over the summit of the volcano with an ash trail extending at about a 2,000 m altitude for about 20 km to the ESE.  Passengers including Dutch Harbor residents James Dickson and Scott Kerr of a later Peninsula Airways Inc. flight, which passed the volcano at about 1900LT, reported that the eruptive activity consisted of a white plume that rose at least 600 m above the summit and that a trail of dark gray ash extended for at least 40 km to the ESE.\r\n   \"Hap Hayden, Ron Saylor, Dave Weyl, and Captain Emil Lindal observed eruptive activity of Mount Cleveland from their ship, the Blackhawk, on the morning of 27 May 1986.  The Blackhawk had just delivered supplies from its cargo barge at Nikolski of Umnak Island.  The wind had come up to 35 km/hr out of the N at 11 degrees E, so the Blackhawk with its cargo barge and landing craft at tow headed to the lee of Chuginadak Island for the purpose of loading its landing craft.  At about halfway to Chuginadak Island at 0100LT, about 35 km E of Mount Cleveland, Mate Hap Heyden could see a glow from the top of Mount Cleveland.  He was also able to detect sulfur fumes.  At about 0235LT, the Blackhawk anchored in a cove on the S side of Chuginadak Island that was 12 km ESE of Mount Cleveland.  Hap was able to recognize an approximate 60 m diameter crater on the ESE summit region of Mount Cleveland.  The crater was oriented such that he could see the back inside wall of the crater.  He could see incandescent lava shooting up to about 30 m above the crater that then was falling back into the crater.  Dave Weyl was also able to recognize an approximate 10 m wide incandescent zone that extended from the crater down the SE side of the volcano by at least 100 m.  Most likely this was a lava channel.  To Dave, the glow from the crater was pulsating.  At about 0450LT, the Blackhawk headed SE.  Ron Saylor then detected a fog-like cloud, which irritated his eyes and throat.  They did not get out of the volcanic cloud until they were S of Herbert Island, which is about 28 km SSW of Mount Cleveland.  No ash was detected on the boat during this entire experience.\r\n   \"At 1845LT 3 July 1986, pilot Tom Madsen observed a 100 m vertical white plume over Mount Cleveland while he was flying to Atka from Dutch Harbor.\r\n   \"Pilot Tom Madsen and J.W. Reeder flew within 35 km N of Mount Cleveland on 10 July 1986 at about 1845LT and again at 2115LT. Only minor amounts of steam were rising from the SE top of the volcano, but the top 250 m of the volcano was black.  In contrast, the nearby Carlisle Island was completely white with snow and the rest of Mount Cleveland was white with snow.\"","StartYear":1986,"StartMonth":4,"StartDay":28,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1986,"EndMonth":5,"EndDay":27,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":151,"Name":"Makushin 1986/4","Description":"   From Reeder (1989): \"At 1900LT 28 April 1986, James Dickson, a resident of Unalaska, while on a Peninsula Airways Inc. flight from Dutch Harbor to Atka, observed a 500 m vertical steam plume over Makushin Volcano.  The top of this plume trailed to the S for at least 40 km.  James detected no obvious ash in the white steam plume.  Pilot Tom Madsen, President of Aleutian Air Ltd. at Dutch Harbor, also flew to Atka from Dutch Harbor earlier the same day (left Dutch Harbor about 1120LT), but the volcano at that time was not visible due to cloud cover.\"\r\n   This activity probably does not constitute a volcanic eruption, and Simkin and Siebert (1994) classify this event as not an eruption.  Additional reports are quoted below.\r\n   From Smithsonian Institution (1986, v. 11, n. 6): \"On 28 April at 0700, James Dickson observed a 450 m vertical steam plume over Makushin that trailed SE for at least 30 km. He detected no ash in the plume.\"\r\n   From Smithsonian Institution (1986, v. 11, n. 4): \"On 20 December, pilot T. Madsen (Aleutian Air) noticed anomalous amounts of steam rising from six large and closely spaced steam vents just E of the summit. The largest plume was 500-600 m high. No ash was observed in the white plumes. Air temperature at 2,400 m was -6.7°C, warm for that altitude. Steaming remained anomalously vigorous for the next two days before returning to a more normal level. Based on John Reeder's observations . . . since 1979, the summit steam activity is continuous and normally reaches heights of 100 m or slightly less.\"","StartYear":1986,"StartMonth":4,"StartDay":28,"StartTime":"07:00:00","StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":73,"Name":"Korovin 1986/5","Description":"   From Miller and others (1998): \"Steam emission was observed in early May, 1986, and on May 23rd a 600 m steam plume containing some ash reportedly occurred soon after a 7.7 magnitude earthquake struck about 100 km to the southwest (Smithsonian Institution, 1986).\"\r\n   From Smithsonian Institution (1986): \"On 6 May], James Dickson noted a 500-m vertical steam plume over the SE part of the summit [of Korovin]. On 23 May at about 1730, Aleutian Air pilot Thomas Madsen noted a 600-m steam plume containing traces of ash rising above the rim of a 240-m-deep crater in the SE part of the summit area. A shallow magnitude 7.7 earthquake centered roughly 100 km [SSW] of Korovin at [51.52N, 174.78W] occurred 7 May [at 2247 GMT].\r\n   John Reeder and Kirk Swanson climbed [Korovin] in July 1983, observing only minor steaming from deep within the crater, rising to only 60 m above its floor.\"\r\n   Reeder (1989) adds the following information: \"Pilot Harold Wilson of Peninsula Airways Inc. on 17 December 1986 observed an impressive above average steam plume from Korovin volcano that contained no detectable ash.  The steam plume completely filled the crater of the volcano and it rose to a 2,250 m altitude (above 800 m above the crater rim) as measured by his Piper T1040 Navaho altimeter.\"","StartYear":1986,"StartMonth":5,"StartDay":23,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Korovin","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak171","ParentVolcanoID":"ak17"},{"ID":176,"Name":"Cone A 1986/11","Description":"   From Miller and others (1998): \"A commercial pilot reported a steam and ash plume above a cinder cone (probably the 1945 cone) in the southwestern part of the caldera on November 18, 1986.  Another small ash eruption occurred from the same cone on January 5, 1987 about 13 hours after a shallow, magnitude 6.6 (Ms) earthquake struck 130 km south of Okmok.  A small pyroclastic flow was produced on the southeast flank of the cone and ash emission from the cone continued intermittently from January 1987 to February 1988 (Smithsonian Institution, 1986, 1987, 1988).\"","StartYear":1986,"StartMonth":11,"StartDay":18,"StartTime":"13:20:00","StartQualifier":12,"StartQualifierUnit":"Hours","EndYear":1988,"EndMonth":2,"EndDay":26,"EndTime":null,"EndQualifier":2,"EndQualifierUnit":"Days","Volcano":"Cone A","ParentVolcano":"Okmok","VolcanoID":"ak56","ParentVolcanoID":"ak206"},{"ID":259,"Name":"Akutan 1987/1","Description":"   From Reeder (1990): \"During 1987, nearly continuous minor steam emissions occurred from the tephra cone in the Akutan summit caldera.  Between 31 January and 24 June, numerous tephra emissions occurred from the caldera cone, causing it to increase in height by about an estimated 100 m.\"  The highest tephra plume went to 4,900 m on February 10, 1987.   Ash plumes were often observed by pilots and by residents of Akutan.  Incandescence was observed on the evening of April 22 (+/- 1 day).  See Reeder (1990) for detailed observations and chronology.","StartYear":1987,"StartMonth":1,"StartDay":31,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1987,"EndMonth":6,"EndDay":24,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":152,"Name":"Makushin 1987/2","Description":"   From Reeder (1990): \"Steam emissions were continuous from a large solfatara field near the summit of Makushin Volcano during 1987.  Larger than normal steam-blast eruptions were observed on 1 and 2 February and again with some particulate matter on 1 and 2 March as described below.\r\n   \"The crew (Hall Ostbevik and others) of the 40 m Great Pacific fishing boat observed in the afternoon of 1 February as they were going E toward Dutch Harbor above average continuous steam emissions from Makushin, Akutan, and Shishaldin volcanoes.  On the evening of 1 February, Shawn Richardson, a resident of Dutch Harbor, observed from Dutch Harbor above average continuous steam emissions from the top of Makushin Volcano, which she estimated reached 600 m above the top of the volcano and which appeared like a large vertical mushroom white cloud.  Such continuous above average steam-blast activity continued throughout 2 February up to at least 1430LT ( = GMT - 9 hours) when clouds obscured the volcano.\r\n   \"At 1845LT 1 March, Benny Golodoff, Suzi Dengler, and Tom Madsen, all of Dutch Harbor, observed from Dutch Harbor a steam plume with minor particulate matter that extended at least 30 km at an unknown altitude to E from the summit of the volcano.  Midday on 2 March, pilot Harold E. Wilson of Peninsula Airways observed several up to 250 m high steam plumes from the summit of the volcano with traces of particulate matter that had also drifted at least 3 km to WNW.  He also observed particulate matter (possibly ash) over snow in the summit region of the volcano.\"","StartYear":1987,"StartMonth":2,"StartDay":1,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1987,"EndMonth":3,"EndDay":2,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":74,"Name":"Korovin 1987/3","Description":"   From Smithsonian Institution (1987): \"On 18 March at 1954 a NOAA 10 satellite image showed three distinct plumes, each 95 km long, drifting ENE. The estimated vent locations were: 52.38N, 174.15W (Korovin's summit); 52.31N, 174.24W; and 52.29N, 174.21W (5.5 km WSW and 6.5 km SW of Mt. Kliuchef, a cone on Korovin's S flank). More accurate locations will be determined by USGS Anchorage. Just before midnight on the same day US Navy pilot Jeffrey Sullivan observed a southward-drifting ash plume rising to at least 3,000 m altitude, lit by an orange 'flame' from Korovin. Smaller orange flickering 'flames' from two other vents at lower elevation were visible. Two of the vents were ~2 km apart and the third vent was ~10 km NE of the other two vents.\r\n   Earlier in the day (at 1300) Julie Dirks and other Atka residents noticed sulfur smells (~18 km from the volcano). Although the weather was clear Dirks did not notice any 'unusual' eruptive activity. On 19 March a SIGMET notice was issued to warn pilots of volcanic ash 185 km on either side of a line from 52N, 175W to 54N, 172W. The warning remained in effect until 0930. Pilots reported that the ash cloud reached 3,600 m.\"\r\n   Additional information from Reeder (1990, Kliuchef): \"Lieutenant Jeffrey Sullivan flying his U.S. Navy P3 Electra from Dutch Harbor to Adak at a 8,200 m altitude, noted about 240 km E of Adak just before midnight on 18 March a large orange flame with smoke to the south that was determined from the satellite imagery to be from Korovin volcano.  Then, about 5 minutes later, Jeffrey could see two more smaller orange flickering flames that were farther to the south and were at a lower elevation than the first flame.  These lower and smaller two flames would have been the two Mount Kliuchef SW flank vents.\"","StartYear":1987,"StartMonth":3,"StartDay":4,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1987,"EndMonth":3,"EndDay":18,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Korovin","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak171","ParentVolcanoID":"ak17"},{"ID":412,"Name":"Kupreanof 1987/3","Description":"   From Neal and others (1995): \"Kupreanof is a deeply eroded stratovolcano with no known historical eruptions.  Holocene debris avalanche deposits have been recognized, however, and there is a vigorous fumarolic area marked by sulfur deposits at an elevation of 1,524 m (5,000 ft).  Steaming from Kupreanof has been noted in the literature as 'eruption reports' in the past (Smithsonian Institution, 1987).\r\n   The Smithsonian Institution (1987) reports that \"MarkAir pilot Jerry Chisum observed ash and steam emission from a solfatara field on the SSW flank [of Kupreanof].\"","StartYear":1987,"StartMonth":3,"StartDay":10,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1987,"EndMonth":3,"EndDay":10,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Kupreanof","ParentVolcano":"Kupreanof","VolcanoID":"ak175","ParentVolcanoID":"ak175"},{"ID":59,"Name":"Great Sitkin 1987/3","Description":"   From Reeder (1990): \"Steve Shivers of the U.S. Geological Survey noted a volcanic eruption plume from the Great Sitkin region on a satellite image from March 18, 1989.  Lieutenant Jeffrey Sullivan noted orange flame in the direction of Great Sitkin just before midnight on March 18, 1987.  Pilot Guy Morgan, observed minor steam emissions from Great Sitkin just prior to March 18, but such activity is common for Great Sitkin.  'Because no anomalous features could be detected on the Great Sitkin volcano as observed by numerous commercial pilots following the above reported eruptive activity, it is concluded that the Great Sitkin eruptive activity probably occurred at the active NW near summit dome.'\"","StartYear":1987,"StartMonth":3,"StartDay":18,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1987,"EndMonth":3,"EndDay":18,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":321,"Name":"Veniaminof 1987/3","Description":"   From Reeder (1990): \"At 1315LT (=GMT - 9 hours) 19 March 1987, Captain Wallace Niles observed from his Northern Air Cargo DC-6 steam and ash emissions from Mount Veniaminof.  The ash plume with steam rose about 200 m above the top of the volcano, and the ash trailed to the SW for up to 40 km.  Captain Edward Livingston earlier that day (about 0900LT) observed from his Reeve Aleutian Airways, Inc. YS-11 no ash and only minor steam emissions from the volcano.\"","StartYear":1987,"StartMonth":3,"StartDay":19,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1987,"EndMonth":3,"EndDay":19,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Veniaminof","ParentVolcano":"Veniaminof","VolcanoID":"ak301","ParentVolcanoID":"ak301"},{"ID":430,"Name":"Iliamna 1987/3","Description":"   From Smithsonian Institution (1987): \"At 0800 on 19 March Reeve Aleutian Airways pilots Edward Livingston and Dale Schram observed a large steam plume rising about 1100 m above the summit. No ash appeared in the plume. Almost 3 hours later Northern Air Cargo pilot Wallace Niles observed a steam plume rising 1,000 m above the summit from a upper S flank vent. The plume drifted NNW. John Reeder noted that minor steam emissions are nearly continuous from Iliamna but a large steam plume is unusual.\"  This activity does not constitute a volcanic eruption.","StartYear":1987,"StartMonth":3,"StartDay":19,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1987,"EndMonth":5,"EndDay":2,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":16,"Name":"Sugarloaf Peak 1987/4","Description":"   Miller and others (1998): \"The latest reported activity occurred on April 13, 1987 when a plume extending 90 km ENE from Semisopochnoi Island was observed on satellite imagery; the plume extended only 15 km ENE several hours later.  On April 24, 1987, a commercial pilot flying about 50 km SE of the island observed that one of the snow-covered peaks, possibly Sugarloaf, was blackened (Smithsonian Institution, 1987).\"\r\n   From Reeder (1990): \"Steve Shivers of the U.S. Geological Survey Anchorage Office noted an eruption plume at about 52 degrees N, 180 degrees W from a 17:31:03LT (=GMT -9 hours) 13 April 1987 U.S. NOAA 9 (orbit number 12028) and from a 21:35:29LT 13 April 1987 U.S. NOAA 10 (orbit number 02966) satellite images.  The narrow plume extended 90 km to ENE on the 17:31:03LT image, and it extended only 15 km to ENE on the 21:35:29LT image.  The source of the eruption plume was located in the Semisopochnoi Island region.\r\n   \"Pilot Harold E. Wilson of Peninsula Airways Inc. observed midafternoon on 24 April a very dark colored volcanic peak on Semisopochnoi Island when all other peaks and the rest of the island appeared completely white with snow.  The upper half of the volcano peak was dark.  He roughly determined that the dark volcanic peak was Sugarloaf Peak, which is located on the very southern part of Semisopochnoi Island.  Harold was at a distance of about 50 km to SE.  At the time, he was unaware of the 13 April NOAA satellite eruption plume images.\r\n   \"On 18 +/- 2 May, workers employed with Chris Berg Inc. observed a small white steam plume from Sugarloaf Peak that did not drift more than 2 km from the volcano.  Their observations of the plume were made from several locations on Amchitka Island.\r\n   \"Jerry Underhill of Fairweather Inc., as reported to pilot Harold Wilson, observed a very pronounced white steam plume from Sugarloaf Peak on the 26 +/- 2 May.  Jerry Underhill is a weather observer for Fairweather Inc. at Amchitka Island.  The white steam plume with possible minor ash rose just above the top of Sugarloaf Peak and then trailed to NE for at least 1.5 km.\"","StartYear":1987,"StartMonth":4,"StartDay":13,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1987,"EndMonth":5,"EndDay":26,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Sugarloaf Peak","ParentVolcano":"Semisopochnoi","VolcanoID":"ak272","ParentVolcanoID":"ak248"},{"ID":6,"Name":"Kiska 1987/4","Description":"   Miller and others (1998): \"On April 15, 1987, a narrow, drifting plume located 60 km east of Kiska Island, was observed on satellite imagery and is inferred to have originated at Kiska volcano (Smithsonian Institution, 1987).\"\r\n   Smithsonian Institution, 1987: 04/87 (SEAN 12:04) Plume on satellite image","StartYear":1987,"StartMonth":4,"StartDay":15,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kiska","ParentVolcano":"Kiska","VolcanoID":"ak161","ParentVolcanoID":"ak161"},{"ID":299,"Name":"Cleveland 1987/6","Description":"   From Reeder (1990): \"During 1987, intermittent steam emissions were very common from the summit of Mount Cleveland.  In addition, tephra and tephra with steam emissions from the summit were observed between 19 June and 28 August.  A fairly large active lava flow, originating from the summit dome-like vent, existed on 23 through 26 June.  The magmatic eruptive activity appears to have ended following a large tephra eruption of the 28 August.\"  Reeder provides a detailed summary of the eruption observations in his report, including reports of tephra emission, a lava dome like feature's growth, lava flows, lava fountaining, lava incandescence, and reports of a detached plume up to 10,600 m that appeared to have originated at Mount Cleveland.  The Smithsonian Institute (SEAN v. 12, n. 8) reports this plume height as 10,000 m.","StartYear":1987,"StartMonth":6,"StartDay":19,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1987,"EndMonth":8,"EndDay":28,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":28,"Name":"Gareloi 1987/9","Description":"   From Miller and others (1998):\"On September 4, 1987, a commercial pilot observed a narrow flow-like feature on the east flank that extended from the north crater rim at 1500 m altitude down to at least 1100 m, below which it was obscured by clouds.  Steam rose 100 m above the flow (?) and the crater was vigorously steaming (Smithsonian Institution, 1987).\"\r\n   Coombs and others (2008) note \"A similar feature was observed from afar during field work in 2003 but we were unable to determine whether it was lava or debris flow.\"","StartYear":1987,"StartMonth":9,"StartDay":4,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Gareloi","ParentVolcano":"Gareloi","VolcanoID":"ak106","ParentVolcanoID":"ak106"},{"ID":95,"Name":"Amukta 1987/9","Description":"   From Reeder (1990): \"On 4 September 1987, flight engineer George Wooliver observed from his Reeve Aleutian Airways, Inc. Boeing 727 a small eruption plume from the top of Amukta Island.  The dark tephra plume rose at least 300 m above the volcano and then drifted to NW for up to 1 km.  George could visually see the NW side of the volcano, while the rest of it was covered by low altitude clouds.  George's observations were made from a 9,750 m altitude at a distance of unfortunately nearly 120 km to N.  George has fortunately flown the Aleutian Islands since the 1950s, and he is well experienced at observing Aleutian volcanic eruptions.\r\n   Normally the only activity of Amukta volcano is the very minor amount of nearly continuous steam emission from several small vents that are located just inside of the Amukta summit crater and on the very floor of the Amukta summit crater.  This information is based on observations made by Harold Wilson of Peninsula Airways Inc., who has flown in the region regularly between September 1983 and July 1987.\"\r\n   From Smithsonian Institution, 1987: \"At about 1000 on 28 August pilots Charles Kozler, Wayne Russell, and George Wooliver (Reeve Aleutian Airways) reported an eruption plume reaching 10.5 km altitude in the vicinity of Amukta, drifting WNW. The FAA issued a NOTAM warning pilots to stay 25 miles [40 km] from Amukta Island. Heavy weather clouds covered Amukta Island so its activity could not be directly observed. Mt. Cleveland, 100 km ENE, was apparently active that same morning and winds were blowing in the direction of Amukta (see Mt. Cleveland 12:08). The origin of the large cloud remains both uncertain and controversial at the time of this report.\r\n   \"On 4 September Wooliver observed a small dark ash plume rising at least 300 m above the summit of Amukta then drifting as much as 1 km NW. Only the NW flank was visible because of cloud cover. His observations were made from 9,750 m altitude from nearly 120 km N. Wooliver has flown in the Aleutian Islands since the 1950's and is experienced at observing eruptions.\r\n  \" Amukta's last known eruptive activity was on 12 July 1984 (BVE, no. 24). Harold Wilson (Peninsula Airways) notes that normal activity * * * is continuous minor steam emission from several small vents just inside the summit crater rim.\"","StartYear":1987,"StartMonth":9,"StartDay":4,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Amukta","ParentVolcano":"Amukta","VolcanoID":"ak10","ParentVolcanoID":"ak10"},{"ID":330,"Name":"Carlisle 1987/11","Description":"   From Reeder (1990): \"At 1500LT ( = GMT - 10 hours) 28 August 1987, Scott Kerr and Pete Galaktionoff, residents of Dutch Harbor, observed from Chuginadak Island as they were climbing Mount Cleveland steam emissions from the summit of Carlisle volcano that rose for several hundred meters.  Such steam emissions were common during the latter part of August.  \r\n   \"Pilot Harold Wilson of Peninsula Airways Inc., who has flown the region numerous times between September 1983 and July of 1987 has never noticed any steam emissions from Carlisle volcano.  Harold feels that if any steam emissions occurred from this volcano during his flights between September 1983 and July 1987, such emissions must have been very minor and certainly nothing like the steam emissions observed by Scott and Pete.   \r\n   \"At 1359LT 16 November, Lieutenant Dave Holman (Captain) and Lieutenant Jay Brown (co-pilot) observed from their Coast Guard C130 eruptive activity of Carlisle volcano.  Steam with some ash was being emitted from summit vent and was rising to about a 2,500 m altitude.  The light colored plume trailed to ENE for up to 30 km.\"","StartYear":1987,"StartMonth":11,"StartDay":16,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Carlisle","ParentVolcano":"Carlisle","VolcanoID":"ak40","ParentVolcanoID":"ak40"},{"ID":440,"Name":"Augustine 1988","Description":"   From Smithsonian Institution (1988):  \"Increased steam emission follows earthquake. At 1405 on 30 July, MarkAir pilots Kriss Paul and Bruce Gorham observed larger than normal steam emission from Augustine. When first observed, the plume was described as dirty steam with dark streaks at 1600 to 1800 m altitude, but it rose to about 2,700-3,000 m altitude within several minutes. At 1530, on their return from Kodiak to Anchorage, the pilots observed the plume spreading E and topping out slightly higher than 3600 m altitude. The volcano has emitted steam continuously since its 1986 eruption. Less than 4 minutes before the plume was first observed, an earthquake with an epicenter of 60.0°N, 153.5°W (about 75 km NW of the volcano) was felt in the lower Cook inlet region. The event occurred at 1401:29 and was located by the Alaska Tsunami Warning Center at a depth of 169 km with a local magnitude of 4.1. The University of Alaska Geophysical Institute seismic network detected two Augustine earthquakes at about 1603 and 1621 with above-normal magnitudes (about 1).\"","StartYear":1988,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":260,"Name":"Akutan 1988/3","Description":"   From Reeder (1991), concerning eruptive activity at Akutan during 1988: \"Only minor but nearly continuous steam emissions from the summit cone were reported up until 26 March 1988 when another series of tephra explosions, principally without steam, occurred from the cone up through 20 July 1988.  One of the largest tephra plumes reached 2.7 km above the summit of the volcano at 0919 LT (=GMT - 8 hours) on June 2.  Minor ash dustings also occurred three times during this 1988 eruptive period at the Akutan village that is 12.5 km to the E of the volcano.  Only minor but nearly continuous steam emissions occurred from the summit cone since 20 July 1988 for the rest of the year.\"  For detailed observations and chronology, please see Reeder (1991).","StartYear":1988,"StartMonth":3,"StartDay":26,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1988,"EndMonth":7,"EndDay":20,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":515,"Name":"Dutton 1988/10","Description":"   Miller and others (1998) summarize the 1988 seismic swarm at Dutton volcano as follows: \"A swarm of shallow earthquakes during July and August, 1988, beneath Mount Dutton (Smithsonian Institution, 1988) sparked a volcano-seismic crisis.  The activity was concentrated in three episodic sub-swarms with the largest event ML=4.0; many of these events were felt sharply at nearby communities; particularly King Cove, causing much concern.  The distribution of epicenters forms a roughly linear zone which extends in a southeast direction about 10 km from the western shoulder of the volcano.  The trend of the epicentral zone is parallel to the direction of maximum horizontal compression resulting from subduction of the Pacific plate and includes a prominent zone of hydrothermal alteration of the country rock.  These similarities suggest that the seismic activity results from fracturing of the country rock as a dike is emplaced beneath Mount Dutton.\"\r\n   Wood and Kienle (1990) also report a seismic swarm at Mount Dutton during 1984-1985.","StartYear":1988,"StartMonth":10,"StartDay":7,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1988,"EndMonth":8,"EndDay":8,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Dutton","ParentVolcano":"Dutton","VolcanoID":"ak83","ParentVolcanoID":"ak83"},{"ID":261,"Name":"Akutan 1989/2","Description":"   From Reeder (1992): \"During 1989, nearly continuous minor steam emissions occurred from the tephra cone in the Akutan summit caldera.  Between February 27 and March 28, several tephra explosions occurred from the caldera tephra cone.\r\n   \"On February 27, 1989, at about 1200, Lawrence Prokopioff, a resident of Akutan village, observed a small vertical blast of ash with steam from the summit tephra cone of Akutan volcano from his small boat just north of Akutan Island.  The plume was large enough to be easily noticed (probably the plume had a height of under 500 m above the volcano).\r\n   \"On March 15 and 0900, pilot Nic Sias of Peninsula Airways Inc. felt an atmospheric shock wave while he was southbound for Dutch Harbor in his Grumman Goose over the west shore of Akutan volcano.  He then noticed the unusual rapid growth and rise of a black eruption plume from the summit tephra cone of Akutan volcano.  The top of the rising plume quickly disappeared into the 1,800 m altitude cloud cover.  The visibility was very good for Nic underneath this cloud cover, but he could not see through the cloud cover.  With no additional eruption observation, he landed at his destination (Dutch Harbor) at about 0930.  Richard Petrie of Trident Seafoods Corporation near Akutan village noticed from his office window the same eruption plume.  Richard was able to see through the broken 1,800 m cloud cover, and he estimated that the black plume rapidly rose up to 2,300 m above the volcano.  The plume changed to a smaller grayish steam plume and then eventually to a much smaller white steam plume.  This sequence occurred over a period of several hours.  At about 1430, David McGlashan, president of the Akutan Corporation, noticed from the Akutan village a small dark gray eruption plume from Akutan volcano that was drifting south.  At about 1500, Pilot Nic Sias and photographer Harold Wilson flew new the volcano.  Some dark steam was being emitted from the summit tephra cone.  Fresh ash covered snow on the entire W and SW flanks of the volcano above a 600 m elevation, which was the only sides of the volcano they got views of.\r\n   \"In the morning of March 16, 1989, David McGlashan reported that a very light ash dusting occurred at the Akutan village the night before.  A trace of ash was easily noticed on window sills in the village.  At 1100, Harold Wilson reported that the summit region of Akutan volcano was white with fresh snow as he flew by it from Dutch Harbor to Anchorage.\r\n   \"Sometime between March 17 and 31, 1989, David McGlashan noticed for the first time that steam emissions were occurring from a crater on the E side of the near summit tephra cone.  Before, all steam emissions were occurring from the W side of the near summit cone.\r\n   \"Craig Leth of FAA noticed on March 28 and 29, 1989, that the top of Akutan volcano was black with fresh looking ash deposits.  Minor steam emissions were occurring at the time.\r\n   \"On March 31, 1989, at about 1945, Lieutenant Commander Steve Rapalus and his crew observed a large white plume above Akutan volcano from his U.S. Coast Guard C-130 as he was flying from Dutch Harbor to Kodiak.  The plume was at least 600 m above the volcano and the top had drifted to the south for up to 7 km.  The plume did appear white to Steve.  Earlier, at 1900, Linda Logan of Trident Seafoods Corporation near Akutan village noticed no eruptive activity from the volcano, which she could see at the time.\"","StartYear":1989,"StartMonth":2,"StartDay":27,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1989,"EndMonth":3,"EndDay":31,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":29,"Name":"Gareloi 1989/8","Description":"   From Reeder (1992): \"At 1430 on August 17, 1989, Evan Klett of the U.S. Fish and Wildlife observed from the Reeve Aleutian Airways Inc. 727 Boeing Jet, flying from Shemay Island to Adak Island, a grayish to black tephra plume that was about 700 m above the northern near summit crater of Gareloi volcano.  The plume covered the top of the 400 m by 260 m near summit crater, which prevented Evan from seeing into the crater.  The tephra plume was definitely originating from the summit crater.\"","StartYear":1989,"StartMonth":8,"StartDay":17,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Gareloi","ParentVolcano":"Gareloi","VolcanoID":"ak106","ParentVolcanoID":"ak106"},{"ID":300,"Name":"Cleveland 1989/10","Description":"   From Reeder (1992): \"During the week of October 22-28, 1989, the crew of the Crystal Sea, who have been pumping fuel from the beached Polar Command, observed a glow at night that was coming from the top of Mount Cleveland.  The Polar Command was beached about 12 km ESE of Mount Cleveland volcano on the south side of Chuginadak Island near Black Peak.\"","StartYear":1989,"StartMonth":10,"StartDay":22,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1989,"EndMonth":10,"EndDay":28,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":442,"Name":"Redoubt 1989/12","Description":"   From Miller and others (1998): \"The most recent eruption at Redoubt began with a major phreatomagmatic, vent-clearing explosion at 9:47 am on December 14, 1989 (Brantley, 1990; EOS, 1990; Miller and Chouet, 1994) after less than 24 hours of intense precursory seismicity.  Three more ash-rich explosions occurred the following day, December 15, with the last blast generating a pyroclastic flow down the Drift Glacier.  The resulting debris flow contained entrained ice blocks as large as 10 m across and crested about 8 m above the river channel near the Drift River Oil Terminal, 35 km downstream (Waitt and others, 1994).  A Boeing 747 enroute from Amsterdam that flew into the ash cloud several hours after the eruption experienced complete engine failure and narrowly avoided tragedy when the crew successfully restarted the engines and safely landed in Anchorage (Casadevall, 1994). \r\n   \"These initial explosive events were just the first of 23 major explosive events between December 1989 and April 1990.  Following the mid-December explosive phases, the crater vent emitted only minor ash and steam for the next 5-7 days.  From December 22 to January 2, 1990, however, a large, over-steepened lava dome grew over the vent.  At 5:48 pm on January 2, the first of two powerful explosions destroyed most of the dome and sent ash plumes to over 12 km.  Massive block and ash avalanches down the Drift Glacier generated the largest debris flow of the eruption, completely covering the 2-km-wide valley floor and spilling into Cook Inlet.  Flood waters entered the oil terminal, as much as 75 cm deep in some buildings, and caused a temporary halt in operations. \r\n   \"Three eruptions occurred in the next two weeks during which time the vent remained open.  The January 8 event occurred with no precursory warnings and the resulting ashfall on the Kenai Peninsula disrupted commerce and transportation.  Open-vent eruptions on January 11 and 16 resulted in minor debris flows down the Drift River.  \r\n   \"After the January 16 eruption, another period of dome growth ensued through mid-February.  This dome was smaller than the earlier dome but larger than succeeding domes (Miller, 1994).  Early on February 15, the dome was destroyed in an explosive eruption that again sent a large debris flow down the Drift River and blanketed the lower Kenai Peninsula with ash.  A pyroclastic flow and surge traveled down the canyon, across the piedmont lobe of Drift Glacier, and swept up the opposite valley wall 700 m topping the ridge (Gardner and others, 1994).  Flow down the Drift River was largely diverted into a side drainage that carried flood waters close to oil storage tanks at the downstream oil terminal prompting reinforcement of the containment dikes surrounding the tank farm.  A new dome began growing immediately following the eruption.  \r\n   \"On February 21, the new, but considerably smaller, dome was destroyed, marking the beginning of a new trend in eruptive behavior.  Characteristically, small domes were emplaced and subsequently destroyed explosively or by gravitational collapse, resulting in debris avalanches down the now ice-free canyon leading down to the Drift River valley, and flooding down the Drift River.  Ten such eruptions followed from February 24 to April 21 at 4 to 8 day intervals.  \r\n   \"Following the April 21 eruption, growth of the present lava dome began and continued through early June.  During the next several months, seismic activity declined dramatically and only steam emissions and minor rock falls from the dome were recorded as the eruption came to an end. \r\n   \"The 1989-90 eruption of Redoubt seriously affected the populace, commerce, and oil production throughout the Cook Inlet region and air traffic as far away as Texas.  Total estimated economic costs are $160 million (Tuck and others, 1992), making this eruption of Redoubt the second most costly in U.S. history.\"\r\n   From Miller and Chouet (1994): \"The eruption produced about 20 significant tephra deposits between December 14 and April 26 (Scott and McGimsey, 1994 - this volume) with a total tephra volume of about 20 to 40 x10^6 cubic m (DRE).  Tephra plumes rose off the pyroclastic flows to altitudes in excess of 10 km (Woods and Kienle, 1994 - this volume) and were carried mainly northward and eastward by prevailing winds.\r\n   Miller and Chouet (1994) also summarize \"The volumes of individual domes ranged from 1 to 30x10^6 cubic m and magma supply rates ranged from 1.8 to 2.5 x10^6 cubic m per day.  Total dome volume is estimated at about 90x10^6 cubic m (Miller, 1994 - this volume [Journal of Volcanology and Geothermal Research, 1994, v. 62]).\r\n   Miller (1994) estimates total bulk volume of the eruption as 0.1 - 0.2 cubic km.","StartYear":1989,"StartMonth":12,"StartDay":14,"StartTime":"09:47:00","StartQualifier":null,"StartQualifierUnit":"","EndYear":1990,"EndMonth":6,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Redoubt","ParentVolcano":"Redoubt","VolcanoID":"ak231","ParentVolcanoID":"ak231"},{"ID":224,"Name":"Pavlof 1990/1","Description":"   From Reeder and others (1993): \"Pavlof Volcano has been quiet since August 1988 (BE no. 28).  On January 5 and 6, 1990, Marsha Brown of the FAA flight service at Cold Bay observed traces of steam rising up to 100 m above the NE summit vent that was trailing to the NE.  The top of the volcano was dark due to the melting of snow around the summit vent.  The volcano has been pure white with snow for the winter up to this time.  On March 5, several eruption plumes were observed [.]\"","StartYear":1990,"StartMonth":1,"StartDay":5,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1990,"EndMonth":3,"EndDay":5,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":262,"Name":"Akutan 1990/1","Description":"   From Reeder (1993): \"Mark Owen of Trident Seafood Corporation in Akutan village reported several short lived and small tephra plumes rising from the summit tephra cone in the Akutan Volcano summit caldera for several days during the latter part of January 1990.  The exact date of this activity is unknown.\"","StartYear":1990,"StartMonth":1,"StartDay":22,"StartTime":null,"StartQualifier":8,"StartQualifierUnit":"Days","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":7,"Name":"Kiska 1990/6","Description":"   Miller and others (1998): \"Steam and minor ash emission from an upper flank vent on June 1, 1990 was reported by an observer on neighboring Amchitka Island (Anchorage Times, June 3, 1990 [Bensman, 1990]; Smithsonian Institution, 1990).  Although a sizeable steam plume was reported during the next several days, ash emission apparently lasted only several hours.\"\r\n   Bensman, 1990: \"Witnesses at a small U.S. Naval transmitter station on Amchitka said they first noticed white steam clouds blowing from the 4,000 foot Kiska Volcano at about 10 am Friday morning.  The workers continued watching as the steam mixed with a dark gray cloud of ash until weather conditions obscured the view about three hours later.\r\n   \"J.A. Ruehle, an electronics technician working at a Navy radar transmission site on Amchitka, shared a pair of binoculars with his co-workers to view the scene from atop a 540-foot plateau.  He said no one was certain at the time what island the plume was coming from.\r\n    \"'I went out the back door of the shop, and it surprised me because I could see the top of the mountain, and I saw the steam coming out of it.  The steam was real visible and it started mixing with dark ash, or clouds coming out of it,' Ruehle said in a telephone interview Saturday.\r\n   \"'You could see it wasn't coming right off the top.  It was coming off the left side and sort of blowing around to the right toward us.  It must have been a fissure off to the left side.  It was so fascinating to me.'\r\n   \"Captain James Fredenhagen, a Reeves Air pilot who took off from Amchitka at about 3 pm, confirmed the eruption had come from Kiska.  He said a small plume of steam was rising slowly from the volcano by then, but that a haze of gray residue had dispursed [sic] into the surrounding skies at about 12,000 feet.\r\n   \"'I classify it as a mild eruption,' Fredrenhagen said.  'We caught sight of it at 7,000 feet.  You could see the haze.  It appeared to be coming from the crater.'\"\r\n   Smithsonian Institution, 1990: 05/90 (BGVN 15:05): \"Steam and ash plume, steam plume rising to 3.5 km\"","StartYear":1990,"StartMonth":6,"StartDay":1,"StartTime":"10:00:00","StartQualifier":1,"StartQualifierUnit":"Hours","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kiska","ParentVolcano":"Kiska","VolcanoID":"ak161","ParentVolcanoID":"ak161"},{"ID":409,"Name":"Hague, Mt 1990/7","Description":"   Steam plumes were observed at Mt. Hague on July 14, 1990.  This activity probably does not constitute a volcanic eruption.\r\n   From Smithsonian Institution (1990): \"On 14 July at about 2100, Richard Mack observed and photographed a white plume that had risen 350-500 m from the SW side of the summit crater of Mt. Hague, near the E margin of Emmons Lake Caldera. A series of pulses slowly diminished in size until sunset at about 2200. Traces of material trailed SSW from the top of the plume.\r\n   \"Mack stated that he had not seen such activity during his 57 years on the Alaska Peninsula. However, during fieldwork in 1946, Kennedy and Waldron (1955) observed six large fumaroles and many other small ones in a steep gully on the SW side of Mt. Hague, at altitudes of ~975-1,150 m. They did not give plume heights, but reported clouds of SO2 and steam rising from the major vents, with a locomotive-like noise that was audible 1/2 km away. The volume of sulfur fumes prevented the geologists from approaching nearer than roughly 100 m from the vents. Sulfur odors were strong many kilometers downwind. Sulfur cones ~1 m high had developed around the vents and extensive deposits of native sulfur were found in the gully. Miller (in Wood and Kienle, 1990) also reported a large fumarolic area on the S side of Mt. Hague.\"\r\n   From Reeder (1993): \"At about 2100 on July 14, 1990, Richard Mack of King Cove observed an eruption plume of smoke (steam with ash or with at least particulate matter) that had just risen at least 500 m (based on photographs, estimated to have risen about 600 m) above the crater rim from the very SW inner side of the summit crater of Mount Hague. * * * The plume emission location was determined by J. Reeder based on photographs, air photographs, and 1:63,360 U.S.G.S. topographic maps to be 55 degrees 22 minutes 21 seconds N, 161 degrees, 58 minutes, 43.3 seconds W.  Traces of particulate matter and/or tephra trailed to SSW from the top of the plume beyond the shore of the Pacific Ocean from the previous apparently continuous emissions from the summit crater.  The emission was fairly continuous, as represented by a series of belches that slowly decreased in size by the time the sun had gone down just before 2200.  Richard made his observations from his fishing boat on the S part of Pavlof Bay just SW of Bluff Point along Long Beach.  \r\n   \"Richard Mack noted some emissions from the same point of Mount Hague during the next morning (July 15), but due to strong winds the emissions did not rise to form impressive plumes like the evening before.  But, the emissions were there.  Richard then left the region.\"","StartYear":1990,"StartMonth":7,"StartDay":14,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Hague, Mt","ParentVolcano":"Emmons Lake Volcanic Center","VolcanoID":"ak113","ParentVolcanoID":"ak93"},{"ID":263,"Name":"Akutan 1990/9","Description":"   From Smithsonian Institution (1990): \"A series of small, short-lived tephra clouds from Akutan were observed in September. No ashfall was noted at Akutan village. Tephra ejection had last been reported in January. Observer's initials, in brackets, follow their information in the chronology below.\r\n   \"6 September: An ash plume was rising 200 m above the tephra cone in the summit caldera at 0910. By 1022, only a thin atmospheric ash layer remained, extending at least 24 km at 1200 m altitude [RL]. At about 1220, a gray cloud reached 1700 m altitude. Ash was again being emitted at 1330, and was drifting E [JRo].\r\n   \"21 September: Tephra plumes rose about 300 m above the summit at 0915 and 1345 [JRi]. Another plume was seen from Akutan village at about 1600 [MO]. At 1815, a dark gray plume rose to an altitude estimated from the ground at 2400 m, then drifted NE [JRi]. A tephra column ejected at about 2030 that was initially black, then faded to a brown tone, grew into a mushroom-shaped cloud that reached approximately 2,400 m above the volcano [MO]. Observers from the village estimated that each of the day's plumes had risen at least 1,200 m.\r\n   \"22 September: A small tephra plume rose about 150 m at 1030. Steam emission was above normal through the day [JRi].\r\n   \"Several similar small tephra clouds were seen during the following days, but no records were kept of dates and times.\r\n   \"30 September: A very dark black plume ejected at 2005 rose about 1800 m and drifted E toward Akutan village [DH].\r\n   \"1 October: At 1055, a dark black cloud rapidly emerged and reached 1,500 m above the summit before moving E. After the initial burst, the plume weakened to a light brown color. Activity was apparently limited to emission of a 60-m steam plume for the rest of the day [MO].\r\n   \"Observers (initials in brackets): David Hamilton and Mark Owen (Trident Seafood, Akutan village); Robert LeBlanc, Jerry Richardson, and Jean Robert (MarkAir).\"","StartYear":1990,"StartMonth":9,"StartDay":6,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1990,"EndMonth":10,"EndDay":1,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":410,"Name":"Hague, Mt 1991/7","Description":"   Steam plumes were observed at Mt. Hague on July 13, 1991.  This activity probably does not constitute a volcanic eruption.\r\n   From Reeder (1994): \"At about 1100 on July 13, 1991, Richard Mack of King Cove observed from his fishing boat, Janice, in the region of Volcano Bay a white plume that was being emitted from within the summit crater of Mt. Hague.  The plume reached a height of about 300 m above the peak of Mt. Hague and had drifted to the SW just beyond the crater rim.  The day was unusually cloudless.  The white plume could be seen all day.  By 2100, the plume was slightly smaller and was drifting WSW beyond the summit crater, but the plume was barely rising above the summit of the volcano.  The plume was visible from Pavlof Bay until about 2145 when darkness occurred.\"","StartYear":1991,"StartMonth":7,"StartDay":13,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Hague, Mt","ParentVolcano":"Emmons Lake Volcanic Center","VolcanoID":"ak113","ParentVolcanoID":"ak93"},{"ID":264,"Name":"Akutan 1991/9","Description":"   From Reeder (1994): \"Tephra emissions from the summit tephra cone of Akutan volcano began September 15, 1991, and have occurred up through November, 1991.\r\n   \"* * * A fisherman from the Seattle based fishing boat Richards reported at Dutch Harbor that he observed from his fishing boat at about 0800 LT September 15, 1991, lots of black material being emitted from the summit tephra cone of the Akutan volcano that rose about 300 meters above the volcano and that drifted sharply to the NE.  The black emission stopped by about 0900.  Shortly after 0900, the volcano billowed white steam with some black material for a short time.\r\n   \"An unknown fisherman other than the above reported at Dutch Harbor that he observed on September 17, some eruptive activity of Akutan volcano.  He made this report without any knowledge of the September 15 observation.\r\n   \"On September 17, pilot Darren Talmadge reported to the FAA Flight Service in Cold Bay, as observed from his MarkAir Express Caravan Cessna 208 during the morning, a very dark gray billowy eruption plume from Akutan volcano that went up to an altitude of about 2,400 m.  Cloud cover obscured the volcano for the rest of the day.  On September 29, Jodeanne Ryan of MarkAir Inc. observed at about 1315 an Akutan eruption plume from the 737 Boeing Jet that had just departed from Dutch Harbor at about 1305.  The mushroomed plume had already formed above the volcano to an altitude estimated to be less than 2,400 m.  The tephra plume was drifting slightly to the NE.  Later on September 29, Mark Owen and his Trident Seafoods Corporation group observed 6 short-lived but impressive tephra plumes form above the volcano.  The first three occurred at 1517, 1520, and then 1535.  These plumes rose within at least 1 minute to an estimated 3000 m above the volcano as black to light brown tephra plumes that drifted to the NW.  At 1800, the Russian yacht, Tarpon, of Petropavlosk-Kamchatsky as it was returning to Dutch Harbor from Seattle on the Pacific side of Akutan Island observed black smoke for 3 minutes hit the clouds above the erupting Akutan summit tephra cone.  A beautiful tephra plume formed sometime between 2000 and 2100 that rose about 4,500 above the volcano as estimated by Mark Owen.  The snow cover on the volcano, which was above the 300 m altitude, was white at the time.  The upper part of the volcano was still covered with cloud, but the plumes could be seen above because the cloud cover was broken.  Bret Joines of Trident Seafoods Corporation at Akutan reported that some fine ash could be detected the next afternoon in the Akutan village region over windowsills.  Mark Owen also observed that the snow on the volcano was then ash covered.\r\n   \"On October 11, MarkAir Express pilot Darren Talmadge observed during the day from his Cessna 208 Caravan two short-lived eruption plumes from Akutan volcano that reached altitudes of 2,400 m and 2,100 m, respectively.  These occurred at about 1030 and 1100, respectively.\r\n   \"The Trident Seafoods Corporation group at Akutan reported an ash dusting in the Akutan village midday on October 13 as noticed in the afternoon on windowsills.  They also noted ash falling through the cloud cover in the afternoon of October 13 at the western end of Akutan Bay.\r\n   \"On October 14, Mark Owen and his Trident Seafoods Corporation group at Akutan observed about 0935 an eruption plume form from the Akutan summit tephra cone that reached a height above the volcano of about 1,500 m.  Pilot Nic Sias of Peninsula Airways Inc. observed from his Grumman Goose the same eruption plume, which he estimated reached a maximum height of 1,800 m above the volcano.  The winds were out of the west.  The Trident group reported nearly continuous steam and black smoke rising over 200 m above the summit tephra cone of the volcano for the entire morning with large blasting events such as occurred at 0935 about every hour.  They felt eruptive activity was occurring earlier in the morning but they could not see it because daylight came just before the 0935 event.  Bret Joines of Trident Seafoods observed 6 dark eruption events rising at least 460 m above the volcano between 1530 and 1730 on October 14.\r\n   \"At 1600, the Dutch Harbor Weather Center (Alaska Aviation Weather Radio) at the Dutch Harbor airport also observed the eruptive activity from Akutan volcano.  Jack Wood of OESI Corporation out of Sparks, Nevada, observed and videoed the from the northern part of Amaknak Island just north of the Dutch Harbor airport an eruption plume rise up to about 1,500 m above the Akutan volcano at a start time of 1721.  The plume then drifted to the NNE.\r\n   \"On October 18, Mark Owen of Trident Seafoods reported that the volcano was steaming continuously during the entire day, with at least six dark 460 to 600 m high short-lived plumes that trailed to the W.  On October 19, Bret Joines of Trident Seafoods reported that the upper part of the volcano was completely covered by cloud, but that the visible 300 m snow line on the volcano was all black with ash all the way up into the clouds.  Their last good snow was on October 15.\r\n   \"Between 0800 and 1000 November 30, Michael Lockhart and Mark Owen of Trident Seafoods Corporation at Akutan village observed a fairly steady-state 600 m high white steam plume above the summit tephra cone of Akutan volcano.  Mark had Michael climb the 700 m ridge N of Akutan village to observe between 1300 and 1500 the impressive eruption of Westdahl volcano to the ENE.  During this time, Michael had excellent views of Akutan volcano, which was not steaming.  He could see fresh ash north of the rim of the Akutan summit crater that must have been deposited within the last 48 hours since their last good snow.\"","StartYear":1991,"StartMonth":9,"StartDay":15,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1991,"EndMonth":11,"EndDay":28,"EndTime":null,"EndQualifier":2,"EndQualifierUnit":"Days","Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":280,"Name":"Westdahl 1991/11","Description":"   McGimsey and others (1995): \"\"A steam and ash cloud rising to more than 6 km above Westdahl volcano [see fig. 36-1 in original text] was first reported by commercial pilots on routine flights along the Aleutian Island chain on November 29, 1991 (BVE no. 31, p. 83-86).  The next day, pilots reported eruptive activity along an 8-km-long fissure that extended from Westdahl Peak northeastward across the glaciated summit area [see fig. 36-2 in original text].  Many pits, craters, and gaping cracks were visible in the ice adjacent to the fissure.  In addition to ash and steam venting, spectacular lava fountains along the lower few kilometers of the fissure fed a lava flow that extended 7 km from the vent and was as much as 1.5 km wide at the front and 5-10 m thick.  An AVO crew aboard a Coast Guard C-130 observed the lava flow on December 3 as well as the still-steaming deposits of a lahar that had advanced 18 km from the vent to enter the sea.  Stormy weather conditions prevented direct observation of the vent area for most of December, 1991, but pilots reported a constant steam plume, usually mixed with ash, punching through the weather cloud cover.  Residents of False Pass, the nearest permanent settlement, 90 km NE of Westdahl Peak, also reported thunder-like rumbling sounds, the occasional smell of sulfur, and light ashfalls on November 30, December 16, 25, and 26 - evidence that the eruption was still continuing.  Steam clouds rose to almost 5 km altitude on January 2-3, 1992.  Ash clouds observed on January 8-9 reached 2.4 km altitude. Satellite images during the late afternoon of January 9 showed the plume extending about 150 km SE.  By January 15, there was no sign of a vertical plume or any other eruptive activity.  Also by mid-January, the lava flow viewed on December 3, 1991 had not advanced, but had widened to cover an area about 2-3 times greater than in December [see fig. 36-3 in original text].\"\r\n   Siebert and Simkin (2002-) estimate this eruption produced 5x10^7 cubic meters of lava.","StartYear":1991,"StartMonth":11,"StartDay":29,"StartTime":"17:00:00","StartQualifier":null,"StartQualifierUnit":"","EndYear":1992,"EndMonth":1,"EndDay":15,"EndTime":null,"EndQualifier":7,"EndQualifierUnit":"Days","Volcano":"Westdahl","ParentVolcano":"Westdahl","VolcanoID":"ak322","ParentVolcanoID":"ak322"},{"ID":484,"Name":"Mageik 1992/3","Description":"   From McGimsey and others (1995): \"On March 3 [1992], a plume-like cloud seemingly originating from Mount Mageik appeared on two successive National Oceanographic and Atmospheric Administration (NOAA) satellite images prompting the Federal Aviation Administration to issue a warning to aircraft of a possible eruption.  AVO responded by compiling pilot reports, analyzing the satellite imagery, obtaining seismic information from the research seismic net in Katmai, issuing an information release, and then dispatching staff on an observation flight to assess the situation; AVO did not, however, confirm an eruption.  Pilots reported smelling sulfur dioxide but detected no gas or ash plume.  The seismic data indicated no unusual seismicity had occurred in the Katmai volcanic group.  Airborne AVO observers found no evidence of eruptive activity at Mt. Mageik or in the areas downwind from the volcano.  AVO then issued an update announcing that no eruption had occurred.  The incident was deemed useful in exercising AVO's response to a potential eruption in a remote area.\"","StartYear":1992,"StartMonth":3,"StartDay":3,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1992,"EndMonth":3,"EndDay":3,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mageik","ParentVolcano":"Mageik","VolcanoID":"ak187","ParentVolcanoID":"ak187"},{"ID":265,"Name":"Akutan 1992/3","Description":"   From McGimsey and others (1995): \"On March 8 at 1645, a pilot reported a small steam plume, possibly containing ash, rising about 2 km above the summit of Akutan (summit elevation 1303 m).  Localized ashfall at the summit accompanied the eruption.  Minor steam and ash plumes (\u003c100 m high) were reported on March 11-12.  On March 22 a pilot reported at 4.3-km-high ash plume at 1637 and fishing vessels off Akutan Island reported ashfall.  A resident of Akutan Village, located 16 km east of the volcano, reported ash plumes rising 450-550 m above the summit on April 7.  Two days later, at 10:00 am AST, a pilot reported an ash cloud at about 3-3.5 altitude, drifting northwest.  On April 26, a pilot reported ash rising to about 2.5 km altitude (1.2 km above summit).  The next report of activity came on May 21 when an observer in Akutan Village saw fresh ash on the snow-covered flank and small ash emissions rising 250-300 m above the summit.  Inclement weather prevented frequent observation of the summit during March-May and there were probably many more plumes than reported.  Nearly continuous low-level emission of ash and steam is typical of historical eruptions at Akutan.  The final episode of activity was reported at 2:45 pm AST on December 18 when a pilot observed a small ash cloud rising several hundred meters above the summit.  \r\n   \"AVO responded to reports of eruptive activity by monitoring pilot reports and satellite imagery, making daily inquiries to observers in Akutan and Dutch Harbor, studying video footage provided by commercial and private pilots, and issuing the information to federal and state agencies and the media.\"","StartYear":1992,"StartMonth":3,"StartDay":8,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1992,"EndMonth":5,"EndDay":31,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":431,"Name":"Iliamna 1992/4","Description":"   From McGimsey and others (1995): \"On April 30, pilot reports of 'a plume to 20,000 ft over Iliamna volcano' set off a chain reaction that culminated in a widespread rumor that an eruption had occurred or was in progess at Iliamna volcano.  Subsequent reports also indicated Redoubt volcano was erupting.  AVO promptly issued a widely distributed information release stating that no eruptive activity had occurred at any Cook Inlet volcano.  Staff spent the afternoon answering dozens of calls and initiating calls in an effort to quell the false reprots.  Nonetheless, the rumormill persisted and by late afternoon local media were announcing that Iliamna had erupted and an ash cloud was headed towards Anchorage.  AVO immediately contacted local government officials and the media to avert the crisis and then issued a final information release explicitly stating that no eruptive activity had occurred.  AVO responds quite frequently to eruption reports by pilots and the general public who mistake fumarolic steam plumes at Iliamna for eruptive activity.\"","StartYear":1992,"StartMonth":4,"StartDay":30,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":573,"Name":"Redoubt 1992/4","Description":"   From McGimsey and others (1995): \"On April 30, pilot reports of 'a plume to 20,000 ft over Iliamna volcano' set off a chain reaction that culminated in a widespread rumor that an eruption had occurred or was in progess at Iliamna volcano.  Subsequent reports also indicated Redoubt volcano was erupting.  AVO promptly issued a widely distributed information release stating that no eruptive activity had occurred at any Cook Inlet volcano.  Staff spent the afternoon answering dozens of calls and initiating calls in an effort to quell the false reports.  Nonetheless, the rumormill persisted and by late afternoon local media were announcing that Iliamna had erupted and an ash cloud was headed towards Anchorage.  AVO immediately contacted local government officials and the media to avert the crisis and then issued a final information release explicitly stating that no eruptive activity had occurred.  AVO responds quite frequently to eruption reports by pilots and the general public who mistake fumarolic steam plumes at Iliamna for eruptive activity.\"","StartYear":1992,"StartMonth":4,"StartDay":30,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Redoubt","ParentVolcano":"Redoubt","VolcanoID":"ak231","ParentVolcanoID":"ak231"},{"ID":313,"Name":"Crater Peak 1992/6","Description":"   For 220 pages of information on the three 1992 eruptions of Crater Peak, please see the USGS Bulletin 2139, available online at: \u003ca target=\"_blank\" href=\"https://www.avo.alaska.edu/pdfs/B2139.pdf\"\u003ehttps://www.avo.alaska.edu/pdfs/B2139.pdf \u003c/a\u003e; this file is 9 MB.\r\n   From McGimsey and others (1995): \"On June 27, after 39 years of quiescence, the Crater Peak vent on Spurr volcano began the first of 3 eruptions (June 27, August 18, and September 16-17) in 1992 (Alaska Volcano Observatory, 1993; Eichelberger and others, 1995).  The eruption was preceded by 10 months of gradually increasing seismicity that culminated in 19 hours of precursory volcanic tremor.  Upwellings in the crater lake and a color change from green to gray were observed three weeks prior to eruption onset.  In response to increasing seismicity and changes in the crater lake, AVO issued an alert on June 8 and observatory scientists briefed local officials on June 17 about potential volcanic activity.\"\r\n   From Eichelberger and others (2005): \"Seismic behavior changed ominously on June 24 when a tremor episode lasted 154 minutes, followed 12 hours later by a similar episode that lasted 142 minutes.  Eight additional tremor bursts occurred within the next 8 hours.  The weekly update of 10:30 a.m. Alaska daylight time (ADT) on June 26 reported 'well above normal' seismic activity but still cautioned that an eruption might not be imminent in view of an absence of long-period (LP) earthquakes.  At about the same time, aerial observations of the crater revealed that the lake had almost completely drained and that several large rocks had impacted the resulting mud flat.  At 12:04 p.m. ADT, tremor that was continuous and stronger than earlier bursts began. AVO formally issued a warning of level of concern color code Yellow at 4:30 p.m. on ADT and went on 24-hour duty.  At 3:00 a.m. ADT on June 27, a swarm of VT (volcano-tectonic) earthquakes struck at 0- to 2-km depths beneath Crater Peak; their rate soon increased to about one every 2 minutes.  Three LP events accompanied this swarm.  Tremor amplitude abruptly doubled at 7:04 a.m. ADT.  This increase in amplitude was later interpreted to represent the onset of eruption, although weather clouds prevented visual verification.  At 7:16 a.m. ADT, AVO began an emergency calldown announcing level of concern color code Orange.  About the same time, telemetry was lost from the seismic station 400 m from the vent and an Alaska Airlines pilot reported that an eruption plume had risen 5,000 m above the cloud cover.  AVO announced color code Red at 9:10 a.m. ADT.  Tremor amplitude gradually increased, peaking between 9:35 a.m. and 10:25 a.m. ADT and registering on stations more than 100 km away.  Pilots estimated the plume at mid-morning as high as 9,000 m and the National Weather Service (NWS) measured a maximum plume height of 14,500 m with C-band radar (Alaska Volcano Observatory, 1993; Rose and others, this volume [USGS Bulletin 2139]).  The tephra cloud moved northward and ash began falling on Denali National Park at 10:30 a.m. ADT.  Debris flows swept southward down narrow drainages and entered the Chakachatna River in three places.  Most debris followed the course of the 1953 lahar.  At about 11:30 a.m. ADT, seismicity decreased abruptly and the eruption was over.  Weather and steam obscured Crater Peak and the eruption plume track from aerial observation on the afternoon of June 27, but paths of the debris flows were visible on the lower flanks of the volcano (Meyer and Trabant, this volume [USGS Bulletin 2139]).\r\n   \"At 9:00 a.m. ADT on June 28, the level of concern was downgraded to Yellow.  Aerial observation revealed a black northward-broadening swath of tephra on snow fields and glaciers.  Ash thickness was about 1 to 2 mm at Denali National Park and Manley Hot Springs, 260 and 420 km north of Crater Peak (Neal and others, this volume [USGS Bulletin 2139]).  This region is sparsely populated and there were no other reports of tephra there.  The ash cloud continued northward to the Beaufort Sea, then it turned southeast into Canada and the coterminous United States, where it became indistinguishable from weather clouds about July 2.\r\n   \"The level of concern color code was downgraded to Green on July 8.  This was done partly on the basis of greatly reduced seismicity and SO2 emission, but also on the basis of analogy to the single-eruption pattern of 1953.  The downgrading to color code Green proved to be premature.\"  The next eruption was on August 18, 1992.\r\n   Eichelberger and others (1995) state that the June 27, 1992 eruption produced 44 million cubic meters of tephra, with a Dense Rock Equivalent (DRE) of 12 million cubic meters.","StartYear":1992,"StartMonth":6,"StartDay":27,"StartTime":"07:04:00","StartQualifier":null,"StartQualifierUnit":"","EndYear":1992,"EndMonth":7,"EndDay":8,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Crater Peak","ParentVolcano":"Spurr","VolcanoID":"ak70","ParentVolcanoID":"ak260"},{"ID":123,"Name":"Bogoslof 1992/7","Description":"   McGimsey and others (1995) summarize this eruption as follows: \"The recent eruption began in early July, 1992.  At about 3:00 pm ADT on July 6, an eruption cloud rising to 3 km above Bogoslof Island was identified on NOAA satellite imagery.  A few hours later pilots visually confirmed the steam and ash plume.\r\n   \"Satellite imagery showed intermittent small plumes through July 13.  Continuous emission occurred during the next two days with the steam and ash plume rising up to 5.5 km and extending 100 km to the SE.  At 4:23 pm ADT on July 17 pilots reported a rapidly rising mushroom-shaped plume up to 4.5 km altitude.  Inclement weather prevented direct observation of the island.  The activity remained intermittent with an episode of vigorous steam and ash emission beginning about 5:00 pm ADT on July 20 that produced a plume as high as 8 km by 1725.  A profusely steaming new lava dome at the north end of the island adjacent to the 1927 dome was first sighted on July 21 and confirmed by U.S. Coast Guard observations and photography on July 24.  The last report of steaming and minor ash emission was July 24, and except for residual steaming of the dome, activity had subsided by late July, 1992.\r\n   \"AVO responded to the eruption by compiling pilot reports, monitoring satellite imagery for ash plumes, collecting photographs and video footage of the activity, and disseminating information to government agencies and the media.\r\n   \"U.S. Fish and Wildlife Service (USFWS) scientists who approached the island by ship several times later in the summer to assess the impact on sea mammals and birds photographed the new dome.  During the summer of 1994, an AVO scientist spent a day examining the island and collecting samples of the new lava dome (Harbin, 1994).\"\r\n   \"The dome, measuring 150 m x 275 m across and approximately 150 m high, has a steep-sided central spire surrounded by prismatically jointed, block debris that originally formed more gentle slopes [see figure 11 in original text].  By the summer of 1994, the northern and northwestern sides of the dome had been reduced to sheer sea cliffs.  The dome is composed principally of gray to black porphyritic hornblende-andesite (Harbin, 1994).\"\r\n   Reeder and McGimsey (1995) report an approximate dome volume for this eruption as 1.6x10^6 cubic meters.","StartYear":1992,"StartMonth":7,"StartDay":6,"StartTime":"15:00:00","StartQualifier":null,"StartQualifierUnit":"","EndYear":1992,"EndMonth":7,"EndDay":24,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Bogoslof","ParentVolcano":"Bogoslof","VolcanoID":"ak29","ParentVolcanoID":"ak29"},{"ID":326,"Name":"Crater Peak 1992/8","Description":"      For 220 pages of information on the three 1992 eruptions of Crater Peak, please see the USGS Bulletin 2139, available online at: \u003ca target=\"_blank\" href=\"https://www.avo.alaska.edu/pdfs/B2139.pdf\"\u003ehttps://www.avo.alaska.edu/pdfs/B2139.pdf \u003c/a\u003e; this file is 9 MB.\r\n   From Eichelberger and others (1995): \"Following the June [June 27, 1992] eruption, seismicity remained low through the first half of August.  Only one shallow and two deep earthquakes were recorded between August 12 and 17.  Because the closest operational seismic station at that time was 5 km from the vent, several attempts were made to reestablish a seismic station on the crater rim.  These were unsuccessful because of poor weather conditions.  At 3:37 p.m. ADT on August 18, a 16-minute episode of weak tremor and several LP [long-period] events began, but these rather obscure events were not identified until post-eruption analysis of the data.  At 3:48 p.m. ADT, a pilot reported an ash-rich plume.  With confirmation of this plume at 4:25 p.m., AVO began a calldown announcing level of concern color code Yellow.  The main eruption began at 4:42 p.m. ADT, when strong tremor was recorded by all Mount Spurr seismic stations.  AVO began a calldown announcing color code Orange at 4:47 p.m.  ADT, but repeated the calldown process 11 minutes later to raise the color code to Red.  By 4:58 p.m. ADT, a subplinian column had risen through low clouds to a height of 11,000 m, and it ultimately reached nearly 14,000 m.  From an aircraft only 2.5 km away, AVO staff observed and videotaped a dark roiling cloud that was periodically surrounded by lenticular shock waves.  Large bombs were thrown 800 m above the vent.  Small-volume pyroclastic flows of breadcrusted blocks descended the east and southeast flanks of Crater Peak; these flows formed coarse, clast-supported lobate deposits with steep-fronted margins.  Other flows mixed with snow and ice high on the cone and became lahars.  A late fusillade of mostly lithic ballistic projectiles, some as large as 1 m, were hurled as far as 10 km southeastward (Waitt and others, this volume [USGS Bulletin 2139]).  More than 170 lightning strikes were detected by the AVO lightning detection system (LDS) during the second half of the eruption (Paskievitch and others, this volume [USGS Bulletin 2139]).  The eruption ended at 8:10 p.m. ADT.\r\n   \"Upper level winds moved the eruption plume east-southeast directly over Anchorage, where it deposited as much as 3 mm of sand-sized ash (Neal and others, this volume [USGS Bulletin 2139]).  A satellite image 44 minutes after the onset of the eruption shows the plume extending 80 km east from the volcano over an area of 20,000 square km.  Three hours after onset of eruption, the leading edge of the plume was 300 km southeast of Mount Spurr, and its area had grown to 21,000 square km.\r\n   \"Ashfall forced the closing of Anchorage International Airport for 20 hours (N.W. Gibson, Anchorage International Airport, written commun., 1993).  Air quality alerts were issued in Anchorage during the fallout period and also on the following day, as vehicle traffic stirred up ash again (R.B. Stewart, Office of Emergency Management, Municipality of Anchorage, written commun., 1993).  Reworked windblown ash continued to reduce air quality until the first snow of autumn, and then it reappeared during the summer of 1993.\"\r\n   Eichelberger and others (1995) state that this eruption produced 52 million cubic m of tephra (14 million cubic m Dense Rock Equivalent).","StartYear":1992,"StartMonth":8,"StartDay":18,"StartTime":"16:42:00","StartQualifier":null,"StartQualifierUnit":"","EndYear":1992,"EndMonth":8,"EndDay":18,"EndTime":"20:10:00","EndQualifier":null,"EndQualifierUnit":"","Volcano":"Crater Peak","ParentVolcano":"Spurr","VolcanoID":"ak70","ParentVolcanoID":"ak260"},{"ID":327,"Name":"Crater Peak 1992/9","Description":"      For 220 pages of information on the three 1992 eruptions of Crater Peak, please see the USGS Bulletin 2139, available online at: \u003ca target=\"_blank\" href=\"https://www.avo.alaska.edu/pdfs/B2139.pdf\"\u003ehttps://www.avo.alaska.edu/pdfs/B2139.pdf \u003c/a\u003e; this file is 9 MB.\r\n   From Eichelberger and others (1995): \"Following the August eruption, deep seismicity gradually increased, and by mid-September it had returned to levels comparable to mid-June.  AVO teams visiting the crater on September 7 and 16 noted nothing unusual.  At about 7:30 p.m. ADT on September 16, however, discrete seismic events and weak tremor were detected by the newly reinstalled crater rim station.  Tremor amplitude increased at 10:25 p.m. ADT, and at 10:33 p.m. ADT, AVO declared concern color code Red and began the emergency calldown.  An eruption began at 10:36 p.m. ADT that lasted 11 minutes.  Incandescence was recorded on the video camera at AVO-Anchorage and on the telemetered slow-scan television camera at Kasilof, 120 km southeast of Crater Peak just south of Kenai on the Kenai Peninsula.  Weak tremor through the next hour foreshadowed the main phase of the eruption, which began at 12:03 a.m. ADT on September 17.  Intermittent bright incandescence could be seen from Anchorage.\r\n   \"The September 17 eruption lasted 3.6 hours.  Pyroclastic flows swept down the south-southeast and southeast flanks of Crater Peak and mixed with snow and ice to become lahars.  These flows were similar in appearance to pyroclastic flows, but they were cool and water saturated hours after emplacement.  Tephra fallout on the Kidazgeni Glacier generated a debris flow that temporarily dammed the Chakachatna River.  Once again, a narrow ballistic field extended at least 10 km from the vent along the south margin of the tephra plume.  The eruption closed with a strong swarm of about 50 VT [volcano-tectonic] shocks between 5 and 10 km in depth, which may reflect readjustment of the conduit after magma withdrawal.\r\n   \"The plume moved eastward, dusted the north edge of Anchorage and deposited about 1.5 mm of ash in Palmer, Wasilla, and nearby communities in the Matanuska-Susitna Valley north of Anchorage.  Very light ashfall was reported in the town of Glenallen, 350 km east of Crater Peak.\"\r\n   Eichelberger and others (1995) state that this eruption produced 56 million cubic m of tephra (15 million m Dense Rock Equivalent).","StartYear":1992,"StartMonth":9,"StartDay":16,"StartTime":"22:36:00","StartQualifier":null,"StartQualifierUnit":"","EndYear":1992,"EndMonth":9,"EndDay":17,"EndTime":"03:39:00","EndQualifier":null,"EndQualifierUnit":"","Volcano":"Crater Peak","ParentVolcano":"Spurr","VolcanoID":"ak70","ParentVolcanoID":"ak260"},{"ID":266,"Name":"Akutan 1992/12","Description":"   From Smithsonian Institution (1992): \"A small ash cloud * * * rose to a maximum altitude of 1.8 km (several hundred meters above the summit) shortly after 1445 on 18 December. The plume was carried ~20 km N, then rapidly dissipated.\"","StartYear":1992,"StartMonth":12,"StartDay":18,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":88,"Name":"Pyre Peak 1992/12","Description":"   From McGimsey and others (1995): \"On December 27, 1992, U.S. Coast Guard pilots reported an ash cloud to 1200 m above Pyre Peak and extending 24 km north.  Intermittent, localized bursts of ash rising 100-200 m and ash accumulation on the south flank were observed on December 30.  The vent was confirmed to be a satellite cone located 1.5 km south of Pyre Peak at the north end of a fissure that produced lava fountains in 1977.  The activity apparently subsided soon thereafter.  No subsequent activity was reported until May 1993.\"","StartYear":1992,"StartMonth":12,"StartDay":27,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1992,"EndMonth":12,"EndDay":30,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Pyre Peak","ParentVolcano":"Seguam","VolcanoID":"ak224","ParentVolcanoID":"ak246"},{"ID":574,"Name":"Churchill, Mt 1993/4","Description":"   From Neal and others, 1996: \"On April 5-6, 1993, seven earthquakes were located in the general vicinity of Mount Churchill, a late Holocene volcano in the eastern Wrangell Mountains and the source of the White River Ash (Richter and others, 1995).  Analysis of the seismicity by AVO seismologists indicated a tectonic rather than volcanic source.  The tectonic nature of the earthquake swarm was mentioned in the weekly update of April 9, 1993.\"","StartYear":1993,"StartMonth":4,"StartDay":5,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1993,"EndMonth":4,"EndDay":6,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Churchill, Mt","ParentVolcano":"Churchill, Mt","VolcanoID":"ak50","ParentVolcanoID":"ak50"},{"ID":575,"Name":"Sanford 1993/4","Description":"   From Neal and others (1996): \"Ground observers in Glennallen reported unusual white cloud formations over Mount Sanford on April 5 and 6, 1993.  Another report on April 8, 1993, indicated that the mountain 'was steaming' from low on the east or south side (there were conflicting reports) and the resultant cloud was boiling up the flank to an estimated 5,000 ft (1,524 m) over the top of the peak.  This level of apparent activity was more than this observer had noted in 21 years of viewing the volcano.  Given the history of rock and ice falls from the shear south flank of the mountain and the fact that the phenomenon was short lived, AVO concluded that the observations were probably related to a large avalanche(s) or to unusual orographically induced weather clouds.  No mention of the event was made in the AVO weekly update.\"","StartYear":1993,"StartMonth":4,"StartDay":5,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1993,"EndMonth":4,"EndDay":8,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Sanford","ParentVolcano":"Sanford","VolcanoID":"ak242","ParentVolcanoID":"ak242"},{"ID":89,"Name":"Pyre Peak 1993/5","Description":"   From Miller and others (1998): \"Explosive ash eruptions along with a lava flow were reported by Coast Guard observers from July 31, 1993 through August 19, 1993; ash clouds were reported to altitudes of 2,500 m at times during this interval.\"\r\n   However, eruptive activity was reported from Seguam as early as May 28. 1993, and this may be the start of this eruption (Smithsonian Institution, 1993): \"A small ash burst, rising through clouds near Pyre Peak, was reported by the U.S. Coast Guard on 28 May. A plume to 3 km altitude was reported on 2 June by the NWS, but it is not known if the plume contained ash.\"","StartYear":1993,"StartMonth":5,"StartDay":28,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1993,"EndMonth":8,"EndDay":19,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Pyre Peak","ParentVolcano":"Seguam","VolcanoID":"ak224","ParentVolcanoID":"ak246"},{"ID":322,"Name":"Veniaminof 1993/7","Description":"   From Neal and others (1996): \"Reports of activity at Veniaminof began in early 1993. Pilots reported a steam plume rising from the volcano on February 18, 1993. Confirmed magmatic activity was first sighted on July 30, 1993. Observers in Perryville reported black clouds rising over the summit beginning at 1430 ADT on July 30, 1993. A white steam cloud was present at other times. A small eruption plume was observed on satellite imagery by the NWS on July 30, but none were seen in the following days. On the morning of July 31, Perryville observers saw a gray cloud rising from the volcano and extending to the south. On August 2, commercial airline pilots observed intermittent venting of black ash clouds rising nearly 300 m (1,000 ft) above the active intracaldera cone. On August 3, U.S. Fish and Wildlife (USFWS) personnel reported a steaming pit in the snow at base of the west side of the intracaldera cinder cone. Pilot reports on August 3 described black ash and bombs erupting from the summit vent of the intracaldera cone at 30-60 second intervals to a height of 2,400 - 3,000 m (7,900-9,800 ft) above sea level (840 m [2,756 ft] above vent). A minor dusting of very fine ash occurred in Port Heiden after 2000 ADT on August 3, 1993. Residents of Perryville, Chignik, and Chignik Lake also heard a \"rumbling noise\" accompanied by a slight tremor at about 2200 that night. Flight restrictions around Veniaminof were put into effect August 4, 1993. On the morning of August 6, a resident of Port Heiden observed eruptions of ash and steam at 3-4 minute intervals; these plumes barely rose above the summit of the volcano. There were no reports of ashfall at other nearby villages. On August 12, a pilot reported ash venting 600-900 m (1,900 - 3,000 ft) above the crater with the ash cloud carried east-northeast.\r\n   \"Poor weather precluded many observations during the fall. On October 1-2, residents of Port Heiden observed steam and ash emissions over Veniaminof. An Advanced Very High Resolution Radiometer (AVHRR) image from the late morning of October 2 -- the first clear satellite image in almost two months -- showed a faint northeast-directed plume and a thermal anomaly at the summit cinder cone. During the night of October 7, residents of Perryville observed bursts of incandescent material rising approximately 300 m (1,000 ft) above the summit. These bursts occurred about once every 10 minutes, were accompanied by loud rumbling sounds, and appeared to be similar in size to the eruptions in July and August. On October 14, residents of Perryville observed continued emission of a gray, steam and ash plume rising about 1 km (3,280 ft) above the summit. Though the summit was obscured by haze on October 22, observations from Perryville indicated a decrease in the level of activity relative to that earlier in the month.\r\n   \"U.S. Coast Guard (USCG) pilots filmed eruptive activity and took photos of the intracaldera cinder cone on November 6, 1993. By then, a new pit (2.0 by 0.75 km [1.2 by 0.5 mi] wide) had formed in the ice adjacent to the cone on the east flank and contained an\r\nactive lava flow [See fig. 4 in original text]. Steam plumes rose from the outer margin of the lava where it came into contact with the ice walls of the pit. An ash-and-steam plume rose up to 2 km (6,560 ft) above the cinder cone, and a thin ash layer covered the ice-filled floor of the caldera.\r\n   \"Activity continued intermittently for the remainder of 1993, (for post-1993 activity see Neal and others, 1995). During favorable wind and weather conditions, Port Heiden residents noted dark ash clouds above the volcano and deep rumbling was reported by residents in Port Heiden and Perryville.\"\r\n   From Neal and others (1995): \"Reports of eruptive activity diminished in frequency with the onset of bad winter weather; however, reports of renewed, intermittent strombolian activity reached AVO in March 1994. On May 9, 1994, during the first AVO overflight, eruptive activity consisted of quiet lava effusion from the vicinity of the intracaldera cinder cone [see fig. 7 in original text]. This lava flow had melted an oval-shaped pit in the summit ice cap estimated to be about 1000 m (3,280 ft) by 800 m (2,625 ft) across and 30-50 m (100-160 ft) deep. Fractures in the ice surrounding the pit suggested subglacial melting. Unlike the 1983-84 eruption, no standing water was visible in the pit. \r\n   \"On June 29, an especially vigorous eruption sent an ash cloud to a reported 4.8 - 5.5 km (16,000-18,000 ft) and the NWS issued a SIGMET (notice of SIGnificant METeorological events.) Additional reports of low ash bursts over the volcano or incandescent strombolian activity viewed at night were received through mid-August. Steam plumes, at times rising several hundred meters, were reported over the volcano until late September. Due to the remote nature of this volcano, the paucity of observations, and the frequently poor weather, we are uncertain of the history of declining eruptive activity in late 1994. However, on Advanced Very High Resolution Radiometer (AVHRR) satellite images unobscured by heavy cloud cover, thermal anomalies were detected in the area of the active intracaldera cinder cone of Mount Veniaminof into early 1995.\"\r\n   The Smithsonian Institution (Bulletin of Global Volcanism, volume 19, number 4) estimates the volume of the 1993-1994 lava field at 16-20 x 10^6 cubic meters.","StartYear":1993,"StartMonth":7,"StartDay":30,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1994,"EndMonth":8,"EndDay":28,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Veniaminof","ParentVolcano":"Veniaminof","VolcanoID":"ak301","ParentVolcanoID":"ak301"},{"ID":154,"Name":"Makushin 1993/9","Description":"   From Neal and others (1996): \"On September 14, National Wildlife Service (NWS) relayed three pilot reports of sulfur smell northwest of Dutch Harbor and one veteran pilot report of \"a trace of ash\" at 4000 feet.  Subsequent investigation turned up the fact that, over the past month, pilots had frequently smelled sulfur and seen \"smoke and steam\" from Makushin, as well as snow apparently darkened by ash.  A similar report was called into AVO on September 23.  On November 5, 1993, AVO received a report from NWS relaying a USCG cutter sighting of eruptive activity at 0930 Aleutian Standard Time.  AVO and NWS examined available satellite imagery and found no anomaly; calls to residents of Dutch Harbor/Unalaska confirmed no ashfall.  A NOTAM was issued by NWS.  As phreatic activity is typical at Makushin, AVO distributed no formal information releases at any time.\"","StartYear":1993,"StartMonth":9,"StartDay":14,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1993,"EndMonth":11,"EndDay":5,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":385,"Name":"Shishaldin 1993/10","Description":"   From Neal and others (1996): \"AVO received a flurry of calls on September 4, 27, and October 4, 1993 relaying pilot reports of vigorous steaming and on one occasion (September 4) 'possible ash' to 3 km.  This was not confirmed by satellite imagery or ground observations of ashfall.  On October 26, an experienced USFWS observer noted ash on the upper 300 m of the cone as well as a gray coloration to the plume emanating from the summit crater.  More pilot reports of steaming were received on October 28.  On October 29, USFWS personnel in Cold Bay reported the steam plume was perhaps 'darker and more vigorous' than usual; NWS also relayed a pilot report of steam to 20,000 ft.  Again, no satellite or ground detection of distant ashfall were noted.","StartYear":1993,"StartMonth":10,"StartDay":26,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":75,"Name":"Kliuchef 1993/12","Description":"   From Smithsonian Institution (1993): \"On 10 December AVO reported the following. 'On 4 December, following a M 5.1 earthquake at 1836 beneath the . . . island of Atka, residents of Atka village reported \"rumbling\" from the cluster of volcanoes that forms the N part of the island. At the same time, residents observed increased steaming from a fumarolic area on the flank of Kliuchef volcano and noted a distinct sulphur smell. A check of satellite imagery did not confirm any change in the surface state of the volcanoes. Late this week, the weather had deteriorated and no visual observations of the volcanoes were possible. . . .'\"","StartYear":1993,"StartMonth":12,"StartDay":4,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kliuchef","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak164","ParentVolcanoID":"ak17"},{"ID":45,"Name":"Kanaga 1994/1","Description":"      From Miller and others (1998): \"The eruption was characterized by steam and ash plumes rising to as high as 7.5 km and drifting a few tens of kilometers downwind, lava extrusion within the summit crater, and minor avalanching of incandescent debris down the north flank reaching the sea in some cases (Neal and others, 1995).  Strong sulfur odors were detected on occasion by ground observers in Adak, 33 km to the east.\"\r\n   From Neal and others (1996): \"Report of increased steaming by U.S. Navy on 2-17-93 (Note: Neal and others (1995) report the first increased steaming observation incorrectly as April, 1993).  Additional pilot reports of increased steaming in April and on 12-29-93; eruption begins in January, 1994.\r\n   From Neal and others (1995): \"Increased steaming from the summit crater and upper flank fumaroles was first reported to AVO on December 29, 1993. (However, AVO subsequently learned that pilots had noted increased steaming as early as April, 1993). Beginning in early January, 1994, minor ash plumes usually rising \u003c 1 km (3,280 ft) over the summit were reported by pilots and residents of Adak.  Photographs of Kanaga Volcano in late January confirmed that a linear vent system extended across the summit crater and part way down the east and west flanks. Ash and steam billowed from discrete segments of the vent and minor debris flow deposits, recognized as dark lobate tongues, extended from the trace of the fissure.\r\n   \"The eruption continued intermittently at a low level into October, 1994. Sightings of ash plumes were hampered by the frequent poor weather which plagues the Aleutian Islands. Most observed eruptive plumes were relatively dilute, rising to altitudes of \u003c 3 km (9,840 ft) and dropping ash onto the flanks of the volcano. During other times, only white steam plumes were visible rising to altitudes of typically \u003c 1500 m (4,920 ft) above the volcano’s summit. At least two significant ash plumes were recorded over the course of this eruption: the first, to ~7.5 km (24,600 ft) occurred on February 21 and the second on August 18, when an eruption cloud reached ~4.5 km (14,760 ft) [see fig. 13 in original text]. A light dusting of ash fell on the community of Adak on August 20. Air traffic was disrupted on August 22 due to continuing low-level activity and cloudy conditions which prevented visual approaches to the Adak air field.\r\n   \"Avalanching of incandescent fragmental debris down the north flank into the sea was first reported in April as 'lava flows' by U.S. Navy pilots. On June 20 aboard the USFWS R/V Tiglax just offshore north of the island, Joe Meehan reported that at 1:45 a.m. local time, during a full moon, the crew observed two incandescent streams of fragmental material cascading down the northwest flank from an elevation of approximately 760 m (2490 ft) to near the shoreline. The upper flanks and summit of the volcano were obscured by clouds so the exact origin of the streams could not be determined. The crew could also not confirm whether debris had reached the ocean. By late July, however, USFWS personnel observed avalanches reaching the ocean and producing powerful littoral explosions. They noted that a new headland had been created.\"\r\n   \"Throughout 1994, Adak residents and pilots of aircraft approaching and departing Adak Island reported occasional sulfur smell under westerly wind conditions. AVHRR satellite imagery intermittently detected a hot spot near Kanaga Volcano summit through October 13.\"\r\n   From McGimsey and Neal (1996): \"Based on satellite and ground-based observations, the eruption had significantly waned or ceased by late November, 1994. However, weather conditions in the Aleutians typically prevent direct observations for days or weeks at a time, and over the next six months, during breaks in the weather, observers in Adak continued to report minor steam plumes above the summit of Kanaga (Smithsonian Institution, v. 20, n. 4, 1995).\r\n   \"On June 3-4, 1995, U.S. Fish and Wildlife Service (USFWS) personnel aboard the research vessel Tiglax observed steaming from the summit and from the area covered by 1994 avalanche deposits on the north flank. Two weeks later, on June 19, a pilot reported seeing possible fresh ash or bare ground due to snow-melt on the west flank, and a weak ash plume up to 300 m (1000 ft.) above the summit. An AVHRR satellite image from June 21 showed a steam plume extended north from Kanaga [see fig. 5 in original text].\r\n   \"The following day, another pilot reported a dirty haze at summit elevation extending 25 km south. AVHRR satellite images recorded a few hours later confirmed a weak thermal anomaly at the summit and a plume extending about 180 km to the north, prompting AVO to issue an information release stating that a small eruption may have occurred at Kanaga. On June 23, the U.S. Navy\r\nMeteorological Office in Adak reported a thin ash cloud at the summit. USCG C-130 pilots observed a dusting of ash on the flank and 3 active steam vents on the south flank (Smithsonian Institution, v. 20, n. 6, 1995). Poor weather prevented observation of the volcano for much of the next 2 months. Occasional observations from Adak confirmed that vigorous fumarolic activity continued high on the southeast flank and minor steaming was still occurring at the summit crater (Smithsonian Institution, v. 20, n. 8, 1995).\r\n   \"The captain of the USFWS research vessel Tiglax (Kevin Bell) reported in mid-October that on October 1 he observed hot blocks cascading down ravines on the north and northwest flank from near the summit--which was obscured by clouds--to as far as sea level, leaving 'steaming contrails' in their wakes (fig. 6). He noted that the activity was similar to that which he had observed during the documented eruptive period of summer 1994, and that the activity would not have been visible from Adak. However, based on the lack of a corresponding satellite-image anomaly or an ash plume visible from Adak, AVO concluded that Kanaga was probably not erupting at that time; what the Tiglax captain witnessed was most likely the continued avalanching of unstable lava masses that accumulated on the northwest flank during 1993-94.\r\n   \"No further activity was reported by pilots or ground observers, and no thermal anomalies were visible on satellite imagery for the remainder of 1995. The last 1995 AVO weekly update to include Kanaga was that of August 25 [1995].\"","StartYear":1994,"StartMonth":1,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1995,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Kanaga","ParentVolcano":"Kanaga","VolcanoID":"ak144","ParentVolcanoID":"ak144"},{"ID":566,"Name":"Makushin 1994/1","Description":"   From Neal and others (1995): \"On January 19, AVO received a pilot report of two distinct steam plumes, possibly containing ash, rising about 1,000 m (3,280 ft) above the summit of Makushin Volcano. AVO received at least one phone call from a major air carrier and one from the U.S. Air Force about the report. The NWS issued a SIGMET.\r\n   \"On January 21, an AVO staff member received a phone call from the Alaska Department of Emergency Services (DES) at 10:45 pm AST. The Chief of Police in Unalaska had contacted the DES to report a strong sulfur smell and unusual lightning. In addition to speaking to the Unalaska Chief of Police, AVO made phone contact with NWS watch officers to obtain satellite information and discussed possible scenarios with DES. It was concluded that the lightning was related to a strong frontal system and associated westerly winds. Additional reports of a robust steam plume were received on January 26.\r\n   \"AVO frequently receives reports of increased steaming at Makushin Volcano. Some observations suggest a small amount of ash is contained in these steam plumes; this is likely the result of vigorous fumarolic or minor phreatic activity.\"\r\n   The Smithsonian Institution (1994) reports this event as a false eruption report caused by a storm.","StartYear":1994,"StartMonth":1,"StartDay":19,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1994,"EndMonth":1,"EndDay":26,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":567,"Name":"Iliamna 1994/4","Description":"   From Neal and others (1995): \"Pilot reports of an exceptionally large steam plume above Iliamna Volcano reached an AVO staff member at home on the night of April 12. The next day, at least one phone call from the local media indicated that word had spread about possible eruptive activity at Iliamna; AVO staff were able to examine seismic data and determine that the volcano was quiet. AVO also responded by including a comment in the weekly update about common sightings of benign (non-eruptive) steam plumes at Iliamna.\r\n   \"At 0939 Universal Time (UT) (1:39 am Alaska Daylight Time [ADT]) on June 30, a large avalanche from the upper east flanks of Iliamna Volcano produced a strong seismic signal as far away as station SLK at Skilak Lake on the Kenai Peninsula 150 km (93 mi) northeast of the volcano. Small shocks were recorded on Iliamna station INE (1585 m [5200 ft] on the northeast flank) as early as 0900 UT (1:00 am ADT); the main event at 0939 UT (1:39 am ADT) saturated the INE record for about 5 minutes. AVO staff examined the strong seismicity the next morning and quickly determined that it was not related to volcanic activity. This information\r\nwas conveyed to Lake Clark National Park. AVO staff subsequently made observations on opportunistic fly-bys and spoke with pilots in the area.\r\n   \"The avalanche deposit was viewed and photographed on July 1 [see fig. 4 in original text]. The headwall is at about 2,200 m (7,220 ft) on the steep east face of the volcano and the avalanche itself extends 5-7 km (3-4.3 mi) to an elevation of approximately 525-600 m (1720-1970 ft).\"","StartYear":1994,"StartMonth":4,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":301,"Name":"Cleveland 1994/5","Description":"   From Neal and others (1994): \"On April 29, pilots reported a robust steam plume, possibly containing ash, emanating from the volcano.  Subsequent satellite image analysis did not confirm ash emission and, on May 10, AVO staff on an overflight of the eastern Aleutian arc saw no ash on the flanks of the partially cloud-shrouded volcano.  On May 25, the NWS received two pilot reports of an ash cloud rising to an estimated 35,000 feet (10.7 km); several SIGMETS were issued.  NWS and AVO analysis of enhanced AVHRR satellite imagery indicated one or possibly two small cloud patches drifting northeast from the volcano out over the Bering Sea.  Based on pilot descriptions and analysis of the satellite image, the eruption was deemed a short-lived burst and not a sustained ash emission event.  U.S. Fish and Wildlife (USFWS) personnel aboard the R/V Tiglax observed fresh ash on the north and east flank of the volcano and evidence of small debris flows on the southwest flank.  AVO staff identified a possible ash plume from Mount Cleveland on AVHRR imagery on October 20, however, no eruption was confirmed.\"","StartYear":1994,"StartMonth":5,"StartDay":25,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1994,"EndMonth":5,"EndDay":25,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":568,"Name":"Kupreanof 1994/7","Description":"From Neal and others (1995): \"Kupreanof is a deeply eroded stratovolcano with no known historical eruptions.  Holocene debris avalanche deposits have been recognized, however, and there is a vigorous fumarolic area marked by sulfur deposits at an elevation of 1,524 m (5,000 ft).  Steaming from Kupreanof has been noted in the literature as 'eruption reports' in the past (Smithsonian Institution, 1987).\r\n   \"* * * On July 22, a pilot reported a steam plume over Kupreanof reaching an altitude of 2,400 m (8,000 ft).  Although steaming from Kupreanof has been noted for at least the last 50 years, the robustness of the plume was considered unusual by this veteran pilot.  No SIGMETS were issued by NWS, however, as no ash was detected.  AVO took no further action.\"","StartYear":1994,"StartMonth":7,"StartDay":22,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kupreanof","ParentVolcano":"Kupreanof","VolcanoID":"ak175","ParentVolcanoID":"ak175"},{"ID":577,"Name":"Sanford 1994/9","Description":"   From Neal and others (1995): \"On September 30, [1994], the National Weather Service (NWS) contacted AVO with a pilot report of a steam plume over Mount Sanford.  AVO contacted the local flight service station in Gulkana and discussed the observation.  Given the clear weather conditions at the time, the transience of the plume, and the history of large gravity slides at Mount Sanford, it was concluded that the observation was probably related to a large avalanche.  No mention of this event was made in the AVO weekly update on volcanic activity in Alaska.\"","StartYear":1994,"StartMonth":9,"StartDay":30,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Sanford","ParentVolcano":"Sanford","VolcanoID":"ak242","ParentVolcanoID":"ak242"},{"ID":386,"Name":"Shishaldin 1994/10","Description":"   From Neal and others (1995): \"Satellite image [of Shishaldin Volcano] shows plume-like cloud on 5-23-94; subsequently confirmed to be meteorological.  Possible ash eruption on 10-4-94; pilot report of steam plume 3 km (9,840 ft) above the volcano with minor amounts of ash.\r\n   \"* * * A plume-like image was recognized on an AVHRR satellite image prompting NWS to issue a SIGMET on the night of May 23, 1994. There were no pilot confirmations of any eruption and it is likely that this feature was a meteorologically enhanced fumarolic cloud.\"","StartYear":1994,"StartMonth":10,"StartDay":4,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":578,"Name":"Martin 1994/12","Description":"   From Neal and others (1995): \"The Weather Forecast unit at Elmendorf Air Force Base reported a plume-like cloud originating from the general region of the Katmai group and moving toward Kodiak Island on December 5 [1994].  A satellite image indicated a possible hot spot at the source of the plume which appeared to be near the Mageik-Martin-Trident volcano cluster.  AVO and NWS checks of concurrent satellite imagery showed nothing unusual and it was concluded that this was a meterological phenomenon.\"","StartYear":1994,"StartMonth":12,"StartDay":5,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Martin","ParentVolcano":"Martin","VolcanoID":"ak189","ParentVolcanoID":"ak189"},{"ID":155,"Name":"Makushin 1995/1","Description":"   From McGimsey and Neal (1996): \"On 12:46 pm AST on Monday, January 30, 1995, USCG C-130 pilots reported a small steam and ash cloud from Makushin Volcano.  The cloud rose to about 2400 m (8000 ft) and was carried northeast from the volcano, prompting NWS to issue a SIGMET that ran until 5 pm AST.  Over the next hour, several pilots reported seeing a dispersing light brown ash plume at Makushin.  All activity subsided shortly thereafter as confirmed by a satellite image recorded at 1:45 pm AST, which showed no sign of the eruption.\"","StartYear":1995,"StartMonth":1,"StartDay":30,"StartTime":"12:46:00","StartQualifier":1,"StartQualifierUnit":"Hours","EndYear":1995,"EndMonth":1,"EndDay":30,"EndTime":"13:30:00","EndQualifier":1,"EndQualifierUnit":"Hours","Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":470,"Name":"Martin 1995/3","Description":"   From McGimsey and Neal (1996): \"On Wednesday, March 15, 1995, the National Weather Service (NWS) received a report that residents in King Salmon, located 92 km (57 mi) to the northwest observed steam plumes rising 600-900 m (2000-3000 ft) over the general vicinity of Mount Martin.  No indication of eruptive activity was detected on satellite imagery.\"","StartYear":1995,"StartMonth":3,"StartDay":15,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1995,"EndMonth":3,"EndDay":15,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Martin","ParentVolcano":"Martin","VolcanoID":"ak189","ParentVolcanoID":"ak189"},{"ID":323,"Name":"Veniaminof 1995/4","Description":"   From McGimsey and Neal (1996):  \"In mid-April, 1995, reports from observers in Perryville and Port Heiden of small dark plumes over Veniaminof coincided with thermal anomalies near the active vent recorded on satellite images (Smithsonian Institution, 1995, v. 20, n. 3). This low-level activity was interpreted to result from interaction of lava with ice and snow causing occasional low-energy ash bursts and steam generation (Smithsonian Institution, 1995, v. 20, n. 4). Perryville residents heard rumblings and booms and witnessed minor ash emission on November 15, 1995, as reported in the last AVO weekly update that included Veniaminof (12-1-95). Summit hot spots were visible on satellite images of November 2, 8, and 17, 1995. No activity was reported in December.\"","StartYear":1995,"StartMonth":4,"StartDay":17,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1995,"EndMonth":11,"EndDay":30,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Veniaminof","ParentVolcano":"Veniaminof","VolcanoID":"ak301","ParentVolcanoID":"ak301"},{"ID":76,"Name":"Kliuchef 1995/5","Description":"   From McGimsey and Neal, 1996: \"Observers in the village of Atka, located 15 km (9 mi) to the south, reported a very strong sulfur smell on Monday, May 1 [1995], and a substantial, but lesser, sulfur smell on Thursday, May 4 coincident with the sighting of a small plume-like cloud over Kliuchef volcano.  Inclement weather on May 1 prevented direct observation of the volcano.  The plumes did not appear on satellite images AVO analyzed that week.  The smell of sulfur has been reported previously in Atka village, however, the odors in May were regarded as particularly strong.  Satellite images on May 3 showed a hot spot on Korovin, possibly corresponding to one of the fumarolic fields.\r\n   From Smithsonian Institution (1995): \"Observers in the village of Atka on Atka Island in the central Aleutians reported a very strong sulfur smell on 1 May, and to a lesser extent on 4 May when they observed a small plume-like cloud over Kliuchef. Fumarolic areas exist on or near both Korovin and Kliuchef volcanoes, N of the village. Korovin was active most recently in 1987, and Kliuchef has had Holocene activity. Satellite images did not reveal any plume-like clouds associated with the island, however, a \"hot-spot\" possibly of fumarolic areas, was observed. A similar sulfur smell was reported by residents in December 1993, at about the same time they felt rumbling from a M 5.1 earthquake (Global Volcanism Network Bulletin v. 18, no. 11).\"","StartYear":1995,"StartMonth":5,"StartDay":1,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1995,"EndMonth":5,"EndDay":4,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Kliuchef","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak164","ParentVolcanoID":"ak17"},{"ID":387,"Name":"Shishaldin 1995/12","Description":"   From McGimsey and Neal (1996): \"Around 6:30 p.m. AST (0330 UTC) on December 23, 1995, the FAA received a pilot report that Shishaldin had apparently erupted, sending an ash cloud to 35,000 ft ASL with prevailing winds carrying the plume to the north and northwest.  AVO analysis of a satellite image taken at 7 pm AST revealed a possible small ash plume extending about 50 km northwest from the volcano.  A resident of Cold Bay, 90 km (56 mi) northeast of Shishaldin, reported that a very light dusting of ash may have occurred about 1:30 am AST the next morning, December 24.  However, low-level winds indicated transport from the southeast, which would have taken ash into the Bering Sea away from Cold Bay.  The ash plume observed on satellite imagery dissipated by mid-day on December 24.\"","StartYear":1995,"StartMonth":12,"StartDay":23,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1995,"EndMonth":12,"EndDay":24,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":338,"Name":"Shrub 1996","Description":"   From Richter and others (1998): During the summer of 1996, a \"helicopter pilot observed an active mud spring low on the north flank of the cone [see fig. 3 in original text] and probably activity from the  summit area near the present fissure vent (Fritz Wohlwend, Trans-Alaska Helicopters, Inc., personal communication 1997).  This activity was never reported publicly, but fortuitously, we flew with this pilot on our first visit to the mud volcano on 21 July 1997.\"","StartYear":1996,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shrub","ParentVolcano":"Klawasi Group","VolcanoID":"ak253","ParentVolcanoID":"ak163"},{"ID":579,"Name":"Wrangell 1996/1","Description":"   From Neal and McGimsey (1997): \"A pilot report of a suspicious cloud rising 5,000 feet near Wrangell Volcano prompted satellite analysis and phone calls on January 18, 1996.  National Weather Service (NWS) contract observers in Glennallen subsequently confirmed that a robust steam plume had been visible over Wrangell for several weeks.  Wrangell has several active fumarolic areas in its summit caldera.  These fumaroles frequently produce steam plumes that are mistaken for eruptive activity.\"","StartYear":1996,"StartMonth":1,"StartDay":18,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Wrangell","ParentVolcano":"Wrangell","VolcanoID":"ak326","ParentVolcanoID":"ak326"},{"ID":580,"Name":"Westdahl 1996/3","Description":"   From Neal and McGimsey (1997): \"AVO detected a plume-like cloud with a negative Band 4-5 signature on an AVHRR image of Unimak Island on the morning of March 1, 1996.  Subsequent analysis with NWS colleagues and lack of any confirmation of an eruption by pilots let to the conclusion that the cloud was meterologic in nature.  The cloud suggested possible activity at Westdahl, which makes up much of the southwest portion of Unimak Island, 50 miles west of False Pass and 125 miles northeast of Akutan.\"","StartYear":1996,"StartMonth":3,"StartDay":1,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Westdahl","ParentVolcano":"Westdahl","VolcanoID":"ak322","ParentVolcanoID":"ak322"},{"ID":267,"Name":"Akutan 1996/3","Description":"   This seismic swarm is not considered to be an eruption of Akutan.\r\n   From Neal and McGimsey (1997): \"On March 10 [1996], a seismic swarm severe enough to seriously alarm residents began beneath the island of Akutan in the eastern Aleutians.  Nearly continuous ground shaking punctuated by occasional large shocks continued for 24 hours.  After a lull, a second swarm occurred on March 13 and lasted for about 18 hours.  During both episodes, felt earthquakes occurred at rates of up to one per minute; 30-40 earthquakes per hour were recorded on a seismic station at Dutton Volcano 270 km to the northeast.  The largest of the individual shocks reached M5.3 and were felt in Dutch Harbor 50 km to the west.  The second swarm caused minor damage to household items, interior walls and plumbing in the City of Akutan, 5 km east of the volcano.  Although interpreted to be the result of a magmatic intrusion, the seismic swarm decayed over the next several weeks and no eruption ensued.  AVO responded to the March seismic crisis by deploying a team to Akutan to install an emergency seismic network and begin real-time monitoring of continuing seismicity (Power and others, 1996).  The team also discussed potential hazards with residents of Akutan and met with various groups of citizens and workers at the seafood processing plant to update them on the situation and potential hazards.  Satellite images were routinely examined for anomalous thermal features or ash clouds.  AVO staff in Anchorage and Fairbanks handled the information flow, interacted with a variety of private and public officials and the media, and established the receiving end of a new seismic data stream from Akutan.  AVO went on 24-hour duty for a period of several weeks while Level of Concern Color Code Orange was instituted.  Subsequently, during the summer, the Akutan seismic network was upgraded as part of the Central Aleutian seismic expansion [see fig. 8 in original text].  During this effort, AVO crews found a 20-km-long system of en echelon ground cracks that presumably formed during this event [see fig. 9 in original text].\"","StartYear":1996,"StartMonth":3,"StartDay":10,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1996,"EndMonth":3,"EndDay":18,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":432,"Name":"Iliamna 1996/5","Description":"   From Neal and McGimsey (1997): \"Two seismic swarms occurred beneath Iliamna Volcano in southern Cook Inlet in 1996.  The first occurred between May 10 to May 28.  The second swarm began abruptly at the end of July and peaked in late August or early September.  Earthquakes as large as M 3.2 and at rates of up to 82 per day were recorded.  The swarm began to decay by late 1996 and appeared to be over by early February, 1997.  Most of the earthquakes during both swarms were shallower than 5 km and nearly all were unequivocal volcano-tectonic (VT) events.\"\r\n   Waythomas and Miller (1999) summarize the activity as follows: \"Elevated levels of seismic activity beneath Iliamna Volcano were recorded by the Alaska Volcano Observatory (AVO) in 1996 (McGimsey and Neal, 1997). Earthquakes as large as magnitude 3.2 and as many as 82 earthquakes per day were recorded between May and September 1996. During this period, an increased flux of carbon dioxide and sulfur dioxide gas was detected over the volcano.\"\r\n   Roman (2000) suggests that \"[t]he coincidence of the swarms with increased volcanic gas emissions suggests hot new magma intruded beneath the volcano in 1996.\"","StartYear":1996,"StartMonth":5,"StartDay":10,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1997,"EndMonth":2,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":388,"Name":"Shishaldin 1996/5","Description":"   From Neal and McGimsey (1997): \"Following the late 1995 eruption (McGimsey and Neal, 1996), AVO staff examined satellite images of Shishaldin on a daily basis and tracked the decay of a hot spot at the summit of the volcano.  AVO also reviewed USCG footage of the volcano taken during routine patrol missions; the footage showed no unequivocal signs of eruptive activity but commonly captured a vigorous steam plume emanating from the summit crater.  Photographs by AVO personnel on May 16, 1996, however, clearly display fresh ash on the upper flanks and crater rim [see figures 7a, 7b, in original text]; no specific eruptive event had been documented to account for this ash, and its origin is unknown.  Based on its fresh and snow-free appearance, it was likely deposited not long before the photos were taken.","StartYear":1996,"StartMonth":5,"StartDay":16,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":581,"Name":"Kanaga 1996/6","Description":"   From Neal and McGimsey (1997): \"Possible small (phreatic?) ash eruption, continued avalanching of debris from cooling lava flows.\r\n   \"On June 11, [1996] a commerical airline crew noted a small, bluish-brown cloud possibly containing some ash, rising a few hundred feet above the summit of the volcano, discoloring the snow.  The flight crew noted a sulfur smell upon descent into Adak.  A ground observer from Adak Island noted dark 'splotches' on the east flank of Kanaga, but a ballistic origin for the pattern was never confirmed.  It should be noted that these observations occurred several days after a M 6.0 earthquake in the area and extensive rockfalls and increased steaming had been observed at Gareloi and Kasatochi volcanoes east and west of Kanaga (USFWS, oral communication, 1996).\r\n   \"The captain of the USFWS research vessel Tiglax, Kevin Bell, photographed Kanaga's north flank from his ship on September 3, 1996 [see fig. 12 in original text].  The extent of lava flows is not much different from that inferred from 1995 photographs; small wisps of steam persisted along the upper reaches of the lava flow on the northwest flank.  Captain Bell said he continued to see material rolling down the steep flank of the volcano during the summer and fall of 1996.\"","StartYear":1996,"StartMonth":6,"StartDay":11,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kanaga","ParentVolcano":"Kanaga","VolcanoID":"ak144","ParentVolcanoID":"ak144"},{"ID":78,"Name":"Korovin 1996/6","Description":"   From Neal and McGimsey (1997): \"Following a pilot report of volcanic ash at 37,000 feet east of Adak, NOAA/SAB detected a plume-like cloud on an AVHRR image of the Atka Island area on June 29, 1996.  Subsequent analysis and lack of any confirming observations of eruptions by pilots led AVO to the conclusion that the cloud was meterologic in nature.  The cloud had suggested possible activity at Korovin, the most historically active stratocone on Atka Island in the central Aleutians (Marsh, 1991). \r\n   From Smithsonian Institution (1996): \"On 29 June, Japan Airlines reported volcanic ash erupting from Atka. In addition, GEOS-9 satellite images showed a possible small ash cloud in the immediate vicinity of Atka. In early May 1995 residents of Atka village observed a small plume-like cloud over Kliuchef and reported a strong sulfur smell (Bulletin v. 20, no. 5).\"\r\n   Although AVO discredits this eruption account, the Smithsonian Global Volcanism Program assigns it a VEI of 2, and attributes it to Kliuchef.","StartYear":1996,"StartMonth":6,"StartDay":29,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Korovin","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak171","ParentVolcanoID":"ak17"},{"ID":96,"Name":"Amukta 1996/7","Description":"   From Neal and McGimsey (1997): \"In early July (date not recorded but it was during the first week), AVO received a fax from the USCG which included a ship-based observation in the vicinity of Seguam Island.  Crew noted a 'large plume of ash and smoke * * * from Amukta.'  They estimated the plume to be 2500-3000 feet high, presumably over the summit of the volcano.  USFWS workers on Seguam were notified but reported seeing nothing unusual in the direction of Amukta.  Satellite images from around the time of the report showed nothing of possible volcanic origin.\r\n   \"On September 18, AVO received a pilot report of an eruption at Amukta.  An Alaska Airlines pilot described an ash plume rising about 1000 feet above the 3500-foot summit of the volcano during flights on both the 17th and 18th.  The plumes extended southward about 10 miles before dissipating.  Satellite analysis on the 19th showed a narrow cloud that extended 22 mi south-southeast of Amukta, but this cloud contained no ash signature in bands 4-5.\r\n   \"We later received Alaska State Trooper videotape -- visual and infrared (IR) from a flight on September 18th.  It shows a brownish ash plume rising in intermittent dark puffs (estimated at 30 second intervals by the flight crew) about 500-1000 feet above the summit, then drifting south (?).  The video captures fallout of ash in progress on the flank of the volcano.  The ash cloud becomes fairly dilute rapidly as it drifts downwind.  As the plane passes over the volcano, the active vent was visible a secondary crater against the inner wall of the main summit crater which appears to be formed by coalescence of several separate steep-walled pits.  A fresh (?) tephra ring defines the active vent, and the main crater rim and upper flanks are covered with brownish tephra.\"","StartYear":1996,"StartMonth":7,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1996,"EndMonth":9,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Amukta","ParentVolcano":"Amukta","VolcanoID":"ak10","ParentVolcanoID":"ak10"},{"ID":225,"Name":"Pavlof 1996/9","Description":"   From Neal and McGimsey (1997): \"Pavlof Volcano, historically the most active volcano in the Wrangell-Aleutian volcanic arc, began a vigorous strombolian eruption in mid-September, 1996 (Neal, 1996). The eruption, which continued into early 1997, occurred only two months after a 6-station seismic network was established near the volcano.\r\n   \"A NWS observer in Cold Bay noted steam and incandescent ejecta above the volcano at about 0830 ADT on September 16.  Analysis of seismic data and NOAA-12 and -14 AVHRR satellite images suggest that the eruption likely began at a very low level by September 11. Over the next few weeks, nearby residents observed intermittent strombolian eruptions from near the summit of the volcano. Pilots reported incandescent bombs the size of pick up trucks accompanied by minor ash clouds alternating with steam plumes rising from a few hundred meters to approximately 2 km above the volcano.\r\n   \"Photographs from overflights on September 23 and AVO video from September 27-30 showed lava fountains emanating from two vents (figs. 4A and 4B). One vent was located on the east edge of an ~150-m diameter crater that indented the northwest summit of the volcano. A second, more active locus of fountaining was perched on the west edge of this crater 100-150 m below the summit.  The two loci of fountaining were about 100 m apart and were generally not synchronous in activity. The east vent was less vigorous overall, producing intermittent puffs of gray to dark gray ash and steam tens of meters high. The west vent was the source of intermittent bursts of incandescent spatter up to 300 m high.\r\n   \"By September 23, a small spatter cone was forming at the west vent and a collar of spatter, spatter-fed flows, and small lahars extended about 500 meters down the ~30 degree northwest flank below the summit crater. A lava flow formed by the coalescence and remobilization of heavy spatterfall and direct spill over from the west vent plunged down the steep flank, melting a narrow channel through seasonal snow and glacial ice. By September 29, the lava flow had reached the base of the cone, about 3.5 km from its source, and was beginning to widen into a lobate fan. Dark lahar deposits extended beyond the toe of this lava flow across the gently sloping ground northwest of the volcano, coming within about 40 m of AVO's seismic station PV6. By late October, a second lava flow issued from the east vent and on December 2, when videotaped by Alaska State Troopers, this flow was the more active of the two and had nearly reached the base of the cone in the saddle between Pavlof and Pavlof Sister.\r\n   \"Eruptive activity became intermittent during the month of December. Seismicity decreased abruptly early on December 4 and ash was not visible above the regional cloud cover that obscured the summit of Pavlof for several days. Brief episodes of heightened seismicity occurred on December 10 (accompanied by at least one pilot report of ash) and December 27. The last reliable observation of ash emission occurred on January 3, although pilots and observers in Cold Bay reported possible minor ash in the steam plume over the volcano on a few occasions through February 6. Collapse of unstable agglutinate and hot fragmental debris on the steep upper cone may well account for some of these small ash plumes. \r\n   \"During the first two weeks of the eruption, occasional elongate clouds (\u003c50 km long) containing minor amounts of ash were detected on NOAA AVHRR satellite images (fig. 5). During the third week, both pilot reports and satellite image analysis documented larger but still diffuse ash clouds trailing as far as 175 km downwind, but they rarely reached more than ~6 km above the sea level.  These clouds varied in length from a few tens to several hundred km and were observed intermittently, weather permitting, through late December.  On November 4, accompanying some of the strongest seismicity of the eruption, a plume was visible in Bands 4-5 extending 350 km  northeast of the volcano.\r\n   \"In addition to elongate plumes, thermal anomalies associated with high temperature material were also recorded near the volcano's active vents and along the two main lava flow paths. The number of saturated pixels on AVHRR images varied from 1 - 15 indicating areas of up to about 18 km2 above 37 degrees C (A.L. Roach, oral communication, 1997). The last significant thermal anomaly was recorded in late December, however \"warm\" pixels were noted during daily analysis of AVHRR data into mid-February.  Pilot reports and observations from Cold Bay confirm continued warm ground around the summit of the volcano as inferred from areas of snow-melt.  \r\n   \"As in the 1986 eruption, the 1996 activity produced rubbly, fragmental lava flows that extend in two main lobes down the northwest flank of the volcano (fig. 6). Early in the eruption, these flows occupied, at least in part, channels cut into the seasonal snow and glacial (?) ice on the volcano's flank.  Melting of this snow and ice produced water and rock mixtures of unknown consistency that flowed out onto the more gently sloping terrain northwest (and possibly northeast) of the volcano. As of this writing, we do not know how far these lahars traveled or what impact they had on the Cathedral River and other drainages around Pavlof.\r\n   \"Very light ashfall was reported in King Cove on the night of October 5-6, Sand Point on October 19, and Nelson Lagoon on October 28.\"\r\n   More from Neal and McGimsey (1997): \"On October 3, based on observed plume heights, the FAA issued a Notice to Airmen (NOTAM) restricting flight below ~7 km and within 10 nautical miles of Pavlof.  Higher levels of seismicity and more energetic ash plumes began on October 15 and in response, the FAA increased the altitude of restricted air space to approximately 8 km and the size of the restricted zone to a 25 mile radius around Pavlof. The FAA continued to enforce this restriction until January 27, 1997.   Although Pavlof ash plumes reached altitudes of 30,000 feet or more on a few occasions, there were no serious disruptions in the North Pacific airways.\r\n   \"There were, however, impacts on local air traffic. On November 4, a United States Coast Guard (USCG) C-130 operating at low level over the Bering Sea was struck by lightning. The flight crew also reported a \"smoky\" smell in the cockpit and a fine dust throughout the plane. Subsequent discussion with the USCG failed to positively identify the source of this material. However, based on NWS forecast winds during the time of this report, it appears unlikely that primary ejecta from Pavlof could have been the culprit; rather, it is possible that low level winds remobilized fine ash from the ground. No sample of the material was recovered for analysis.\r\n   \"On November 27, 1996, a Reeve Aleutian Airways flight aborted landing into Sand Point when the pilot detected a brown haze that he interpreted to be ash from Pavlof.\"\r\n   McNutt (1999) calculates a dense rock equivalent volume of material erupted during this eruption as ~7 x10^6 cubic meters.","StartYear":1996,"StartMonth":9,"StartDay":16,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1997,"EndMonth":1,"EndDay":3,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":46,"Name":"Gareloi 1996/9","Description":"   From the Smithsonian Institution (1996): \"On 27 September the Aviation Weather Unit in Alaska received a pilot report of a minor eruption of ash and steam at Gareloi. The plume reportedly rose to 1,500 m altitude but was not visible on infrared satellite imagery suggesting it may have not ascended that high. As late as 5 December AVO had learned of no further sightings of activity at Gareloi.\"","StartYear":1996,"StartMonth":9,"StartDay":27,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Gareloi","ParentVolcano":"Gareloi","VolcanoID":"ak106","ParentVolcanoID":"ak106"},{"ID":485,"Name":"Mageik 1997","Description":"   From McGimsey and Wallace (1999): \"On Thursday, February 19, 1997, AVO received multiple pilot reports (PIREPs) of ash and steam rising to 5,000 ft (~1,500 m) above either Martin or Mageik volcanoes.  No anomalous seismic activity was recorded on the Katmai seismic network, and no indication of eruptive activity was detected on satellite imagery.   \r\n    \"* * * Another observation of unusual steaming at Martin and Mageik was reported to AVO on December 11, 1997, via the Alaska Tsunami Warning Center, who received the report from a resident of Karluk Village on Kodiak Island.  Using a spotting scope, the village resident had observed the peaks for the previous three weeks - noting no unusual activity - when on the morning of the 11th he witnessed a sudden increase in steam activity and watched as white, towering steam clouds billowed from Martin, subsided, and then rose again to about 600-700 ft (~200 m) above the vent, forming a large mushroomed top before dissipating.  A second white, billowing steam plume then rose from adjacent Mageik.  Local pilots also noticed the unusually vigorous activity.\"  This steaming does not constitute a volcanic eruption.","StartYear":1997,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mageik","ParentVolcano":"Mageik","VolcanoID":"ak187","ParentVolcanoID":"ak187"},{"ID":177,"Name":"Cone A 1997/2","Description":"   From Grey (2003): \"The latest eruption at Okmok began on or shortly before February 11, 1997 and originated at Cone A.  An excellent synopsis of the eruption is found in U.S. Geological Survey Open-File Report 99-448 (McGimsey and Wallace, 1999) and is paraphrased here.  Possible precursory activity included a steam plume observed by a passing pilot on November 11, 1996.  The next report was of a dark plume, witnessed by a pilot and passengers en route from Atka to Dutch Harbor on February 11, 1997.  Because these observations were not immediately reported, and because AVO did not yet have seismic instruments deployed on Umnak Island, AVO first became aware of unrest at Okmok with the detection of a thermal anomaly in Advanced Very High Resolution Radiometer (AVHRR) satellite imagery on February 13, 1997.  The beginning of the eruption was confirmed with a phone call from ranchers at Ft. Glenn, 15 km E of Cone A, who reported a dark plume rising to 3000 m ASL and drifting to the SW.\r\n   \"Inclement weather prevented further observation until February 18, when pilots reported an ash plume to 4600 m, and ranchers at Ft. Glenn reported a red glow reflected on the underside of clouds over the caldera.  This was the first verification of lava at the surface.  The thermal anomaly detected in AVHRR imagery continued to grow to 22 pixels by February 22.  At this time, A Ft. Glenn rancher who had climbed to the caldera rim reported a lava flow extending 0.8 to 1.5 km northeast from Cone A.  On February 28, a National Oceanic and Atmospheric Administration (NOAA) research crew passing by in a helicopter spent about twenty minutes flying inside the caldera, capturing six minutes of video footage and several still photographs of strombolian fountaining activity at Cone A.  The photos document that the first (NE) lava flow lobe had reached its full length of 5.5 km from the base of Cone A by February 28 [ see figure 4.9 in original text], and the second (N) lobe had not yet begun to emanate from the cone.\r\n   \"The satellite thermal imagery suggest that the second (N) lobe began to form sometime between March 1-4 (Moxey and others, 2001).  Over the next three weeks, several pilot reports (PIREPs) were issued and satellite imagery continued to show high thermal activity and occasional ash plumes (AVO, unpublished data).  On March 11, a PIREP reporting ash to 9000 m prompted the Federal Aviation Administration (FAA) to issue a NOTAM (Notice to Airmen; contents unknown).  The largest thermal anomaly in AVHRR was on March 12 with 19 saturated pixels (Patrick, 2002).  This probably coincides with the maximum areal extent of the lava flow, while low-level effusion, perhaps reactivated on the first (NE) lobe, likely continued until sometime between March 26-31 (Moxey and others, 2001; Patrick, 2002; Patrick and others, 2003). The presence of multiple flow units within the distal portion of the first (NE) lobe, as seen on Ikonos imagery and in the field suggest multiple pulses of effusion on this part of the flow.  Three units were initially recognized, but field investigations suggest that the third (top) unit is perhaps an apparent additional unit, the result of lava flowing over a drop in the underlying 1958 flow.  Intermittent ash bursts and low plumes continued for the next several months (McGimsey and Wallace, 1999).\r\n   \"When the 1997 eruption of Okmok was over, the resulting lava flow covered a total area of 8.8 square km or about 10% of the caldera floor, based on the lava flow map produced in this study.  Previous estimates range from 7.5 square km (Moxey and others, 2002) to 9.8 square km (Lu and others, 2003).  With thickness varying from 5-45 m (Lu and others, 2002 and Lu and others, 2003), the calculated bulk volume is 1.5 x 10 ^8 cubic m (Lu and others, 2003).\"","StartYear":1997,"StartMonth":2,"StartDay":13,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1997,"EndMonth":5,"EndDay":23,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Cone A","ParentVolcano":"Okmok","VolcanoID":"ak56","ParentVolcanoID":"ak206"},{"ID":97,"Name":"Amukta 1997/3","Description":"   From McGimsey and Wallace (1999): \"On March 3, 1997, Dutch Harbor air-taxi operator Tom Madsen reported seeing a small ash eruption at Amukta with the cloud barely clearing the top of the cone.  No evidence of eruptive activity was detected from analysis of satellite images.  The PIREP was included in AVO weekly updates of March 7 and 14.  Absence of seismic instrumentation coupled with remoteness of the area requires AVO to rely mainly on PIREPs and satellite imagery for monitoring the volcanoes of the central and western Aleutians.  No further information on Amukta was reported to AVO.\"","StartYear":1997,"StartMonth":3,"StartDay":2,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Amukta","ParentVolcano":"Amukta","VolcanoID":"ak10","ParentVolcanoID":"ak10"},{"ID":302,"Name":"Cleveland 1997/5","Description":"   From McGimsey and Wallace (1997): \"On May 5, 1997, the U.S. Coast Guard relayed to AVO a PIREP of a steam and ash cloud rising from Cleveland at 1600 ADT.  The USCG C-130 crew took video footage to document their observations.  The activity was characterized by the pilots as profuse steaming from the summit crater with intermittent, pulsing, bulbous emissions of ash.  Summit snow cover was distinctly marked with patches of black (either ash or bare ground) that extended down the flank, and the plume visibly extended for about 50 km (~30 mi) downwind.  The activity appears similar to that reported in 1994 (Neal and others, 1995).  AVO analysis of satellite imagery revealed a small hot spot.  No information release was issued and AVO received no further information.\"","StartYear":1997,"StartMonth":5,"StartDay":5,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":433,"Name":"Iliamna 1997/5","Description":"   From McGimsey and Wallace (1999): \"On May 19, 1997, seismicity at Iliamna abruptly and dramatically increased.  Analysis by AVO seismologists suggested that the activity probably resulted from a local avalanche or rockslide.  A large avalanche of mixed snow, rock, and ice cascaded down the east flank on June 30, 1994, producing a similar seismic signature (Neal and others, 1995). An AVO field crew dispatched to make observations verified that indeed a large avalanche, composed mostly of ice and snow with some rock debris, had originated at the 7,500-foot (~2,300-meter) level and had cascaded down the east flank, mimicking the 1994 avalanche.\"  This activity does not constitute a volcanic eruption.","StartYear":1997,"StartMonth":5,"StartDay":19,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":582,"Name":"Wrangell 1997/6","Description":"   From McGimsey and Wallace (1999): \"On June 3, 1997, AVO received a pilot report of steam rising from the summit of Wrangell Volcano.  Three weeks later, on June 24, another report described a steam plume rising up to 700 ft (~213 m) above the summit.  No sign of activity was observed on satellite imagery and no mention was made in the AVO weekly update.  Several active fumaroles in the summit caldera frequently produce steam plumes that are mistaken for eruptive activity.\"","StartYear":1997,"StartMonth":6,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Wrangell","ParentVolcano":"Wrangell","VolcanoID":"ak326","ParentVolcanoID":"ak326"},{"ID":389,"Name":"Shishaldin 1997/6","Description":"   From McGimsey and Wallace (1999): \"On Monday afternoon, June 2, 1997, a NWS observer in Cold Bay, 96 km (60 mi) northeast of the volcano, viewed through field glasses a steam and ash plume rising about 1,000-1,500 ft (~300-450 m) above the summit vent and drifting 3-4 mi (5-6 km) to the north.  At the time, the volcano was not seismically monitored.  This eruptive activity appears to be similar to that documented in 1993 (Neal and others, 1996), and 1994 (Neal and others, 1995).\"","StartYear":1997,"StartMonth":6,"StartDay":2,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":519,"Name":"Kukak 1997/6","Description":"   McGimsey and Wallace (1999) write that \"On Wednesday, June 3, 1997, a U.S. Coast Guard helicopter crew reported greenish discoloration on snow and steaming from several vents on a 7,000-ft-high (~2,100 m) peak north and east of Mt. Katmai. A minor anomaly was noted on satellite imagery and the source of the activity was suspected to be either Snowy Mountain or Kukak Volcano, both of which have active fumaroles (Wood and Kienle, 1990). During the early 1980s, fumarolic activity was more vigorous at Kukak than at Snowy (C. Nye, oral communication). Both volcanoes are extensively ice covered [see fig. 9 in original text]. The fumarolic activity and lack of significant erosional dissection of the flanks suggests youthful activity; however, no historic eruptions have been reported.\"","StartYear":1997,"StartMonth":6,"StartDay":3,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kukak","ParentVolcano":"Kukak","VolcanoID":"ak174","ParentVolcanoID":"ak174"},{"ID":339,"Name":"Shrub 1997/6","Description":"   From McGimsey and Wallace (1999): \"The present [1997] activity was first noticed by Alaska Department of Fish and Game personnel on June 12, 1997.  AVO and National Park Service field crews visited the site on June 21, June 30, and on August 13, 1997, and found that most of the gas and mud emission was occurring from at leaset four areas on the summit and north, northwest, and southeast flanks [see fig. 7 in original text].  The activity ranged from quiet effusion of CO2 from collapse pits to vigorous gushing of mud and gas from fissures and mud pots -- some up to heights of 10 m (33 ft) above the vent -- which flowed in streams down the flanks forming mud fans along the base of the cone [see fig. 8 in original text].  Measured mud temperatures were between 43,8C (110.8F) and 46.4C (115.5F).  Voluminous quantities of CO2 flowed as streams down the flanks in several locations, killing vegetation to heights of as much as 2 meters (6.6 ft) above the ground surface.  Small mammals and birds perished around several of the CO2 vents, indicating a potential CO2 hazard.\r\n   \"Following the August site visit and AVO hazard assessment, the National Park Service issued a formal public warning of potentially dangerous CO2 levels at the volcano.  An aerial survey of the area on December 2, 1997, confirmed that mud and gas discharge continues.\"\r\n   From Richter and others (1998), concerning activity at Shrub during the summer of 1997: \"The most active area was immediately below (southeast of) the cone's summit where a 65-m-long east-trending fissure was discharging copious amounts of mud and gas at 43 degrees C.  Recently dead spruce trees on the slopes below this fissure suggest that area was also the site of summit activity in 1996.  Mud and gas production was also vigorous a central vent, about 1 m in diameter, within a group of three vents, about 100 m west of the fissure vent.  The other vents in this latter group were less active.  Approximately a third of the way down from the summit on the north side of the cone, in dense alder-willow-birch growth, a 4- to 6-m-diameter pit, 1- to 2-m-deep, was filled with very active bubbling mud.  Although the pit had not discharged mud, leaves of alder and birch downslope from the bit were browned to heights as much as 2 m above the ground surface suggesting that significant mounts of CO2-rich gas may have flowed out of the pit prior to our visit.  We did observe a dense layer condensate (probably water mixed with CO2) up to about a meter above the roiling mud surface.  Northwest of this gas/mud pit and lower on the con's flank a number of small vents were quietly discharging mud, with no apparent gas, through a thick surficial organic mat.  Mud discharging from the largest of these vents had a temperature of 47 degrees C, the hottest recorded on the mud volcano.\"\r\n   They further report that on June 30 \"the fissure was still active but activity was restricted to a deep (about 3-5 m) pit in the middle of the fissure; temperatures remained at 43 degrees C.  The northernmost of the gushing vents was very active, noisily producing large bubbles of mud as much as 2 m in diameter that burst as high as 10 m above the vent.  There was minor mud emission from the central vent and the southernmost vent was inactive.  The mud/gas pit on the north flank was not visited, but we could see from the air that it was still active.\"\r\n   And on August 13 vigorous mud and gas emission continued.  \"The fissure vent was virtually inactive.  In the deeper parts of the fissure some roily mud was present but none was reaching the surface.  About 50 m south of the fissure a small pit (vent) was discharging a thin trickle of mud.  At the gushing vents the former weakly active vent was now the major producer of mud and gas.  The temperature was 46OC, ~3OC higher than measured on 21 June, and it was estimated that mud production was on the order of a cubic meter a minute.  The formerly very active vent to the north was discharging some mud and a fourth - probably new - vent a few meters farther to the north was also active.  The mud/gas pit lower on the north flank was also inactive, but about 10 m upslope from the pit was a new 3-m-wide collapse pit, at least 5 m deep, which appeared to have active mud at the bottom.  At the mud vents lower down the flank of the cone it appeared that mud emission had decreased, but there were so many small vents, all hidden in the dense vegetation, that it was difficult to tell where and how much mud was being discharged. Between the 30 June and 13 August site visits there had been significant mud production from these lower vents as indicated by the covering of additional 1996 mud during this time frame.  A temperature of 44OC was slightly lower than what was measured on 30 June.\r\n   \"A low-level flight over the mud volcano on 2 December 1997 revealed that activity continued at about the same level as observed in August.  At the original mud/gas pit on the north flank of the cone, which was quiet on August 13, a small stream of mud was observed issuing from the pit and running down the cone.  At the gusher vents it appeared a depression as forming, maybe similar to the basinal feature observed by Nichols and Yehle (1961) in 1955-56.\"\r\n   Richter and others collected gas samples on June 30, 1997, and analyzed.  Analyses show \"the sample contains over 98% CO2 with minor to trace amounts of N2, O2, CH4, Ar, and He.  H2, C2H6, H2S, and CO are below detection.\"  Richter and others (1998) state that the \"bulk composition of the 1997 Shrub gases [see table 1 in original text] is very similar to past analyses from Upper and Lower Klawasi mud volcanoes (e.g., up to 99% CO2; Reitsema, 1979; Motyka and others, 1989), suggesting the 1997 Shrub mud volcano gases come from the same origin.  This is confirmed by the [little delta] [superscript 13] C in CO2 and [superscript 3]He/[superscript 4]He data [see table 1 in original text], which lie within the range of previous analyses of the Upper and Lower Klawasi gases.\"","StartYear":1997,"StartMonth":6,"StartDay":12,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1997,"EndMonth":12,"EndDay":2,"EndTime":null,"EndQualifier":6,"EndQualifierUnit":"Months","Volcano":"Shrub","ParentVolcano":"Klawasi Group","VolcanoID":"ak253","ParentVolcanoID":"ak163"},{"ID":583,"Name":"Sanford 1997/9","Description":"   From McGimsey and Wallace (1999): \"A Copper Center resident reported a large steam cloud rising from the southwest face of Mt. Sanford on September 30, 1997.  The cloud persisted throughout the afternoon before dissipating.  Based on previous similar activity, AVO staff concluded that the cloud resulted from avalanching or debris fall from the southwest face.\"","StartYear":1997,"StartMonth":9,"StartDay":30,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Sanford","ParentVolcano":"Sanford","VolcanoID":"ak242","ParentVolcanoID":"ak242"},{"ID":182,"Name":"Chiginagak 1997/10","Description":"   From McGimsey and Wallace (1999): \"On October 22, 1997, AVO began receiving pilot reports of increased steaming, snowmelt, and sulfur smell at Chiginagak.  Residents of Pilot Point and surrounding areas also reported that they began noticing an increase in steam emissions possibly as early as mid-summer 1997.  A thermal anomaly was detected on Advanced Very High Resolution Radiometer (AVHRR) imagery analyzed on October 23, 1997 [see fig. 10 in original text].  During a flight around the volcano on October 30, AVO scientists observed an enlarged area of fumarolic activity and new fumaroles at about 6,300 ft (~1,900 m), directly above the previously known fumarole site.\r\n   \"AVO reported the activity at Chiginagak in the weekly update of October 31, 1997, and in updates through year's end, including GVN (Smithsonian Institution, 1997, v. 23, n. 3).  Daily, and later weekly, correspondence was maintained with local residents for observations, and AVO closely monitored satellite imagery for signs of increased activity.\"\r\n\r\n      From McGimsey and others (2003): \"In October 1997, following pilot reports of increased steaming and the presence of a thermal anomaly on satellite imagery, AVO scientists traveled by fixed-wing aircraft to the volcano and observed an enlarged area of fumarolic activity and new fumaroles on the north flank of the volcano (McGimsey and Wallace, 1999). A second observation flight was conducted on March 11, 1998. Winds were relatively calm but the areas of interest were largely obscured. However, observers noticed an absence of steam emissions from the area where the lower fumaroles had been located. Bulbous white clouds lingered above the area of the new fumaroles. A very strong sulfur smell -- much stronger than that from the fall of 1997 -- was reported, as well as a yellow color to the ice that formed on the plane's windows. AVO received no further reports until August 13, 1998, when USFWS personnel and a resident of Pilot Point [see fig. 1a in original text] observed little clouds of \"black smoke\" accompanied by a \"greenish-yellow gas\" rising from two point sources to about 500 to 1,000 ft (~150 to 300 m) above the mountain. A dusting of dark material was observed on fresh snow on the upper flanks of the volcano the next morning. On August 15, AVO detected a 30-km-long (19 mi) plume extending east from the volcano. Although the plume contained no ash signal, this was the first time a plume had been observed in satellite imagery of Chiginagak.\r\n   \"On September 29, 1998, AVO conducted an airborne ultraviolet correlation spectrometer (COSPEC) flight to Chiginagak and measured between 200-300 tonnes per day of SO2 emanating from the fumarolic field. Observers reported a vigorous fumarole at an estimated 1,980 m (6,500 ft) elevation on the north flank, adjacent discolored ice and snow, and a strong sulphur smell [see fig. 8 in original text]. The weaker, second fumarole reported in October 1997 was no longer present.\r\n   \"AVO described the activity at Chiginagak in the weekly updates of January 2 and 9, 1998 (continued from 1997), and August 14 and 21, 1998. Although no formal call-downs occurred, AVO shared information informally with the FAA following the August activity. AVO maintained contact with local residents and USFWS personnel throughout the year, and AVO closely monitored satellite imagery for signs of increased activity.\"","StartYear":1997,"StartMonth":10,"StartDay":22,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1998,"EndMonth":8,"EndDay":21,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Chiginagak","ParentVolcano":"Chiginagak","VolcanoID":"ak49","ParentVolcanoID":"ak49"},{"ID":471,"Name":"Martin 1997/12","Description":"   From McGimsey and Wallace (1999): \"On Thursday, February 19, 1997, AVO received multiple pilot reports (PIREPs) of ash and steam rising to 5,000 ft (~1,500 m) above either Martin or Mageik volcanoes.  No anomalous seismic activity was recorded on the Katmai seismic network, and no indication of eruptive activity was detected on satellite imagery.\"\r\n    \"* * * Another observation of unusual steaming at Martin and Mageik was reported to AVO on December 11, 1997, via the Alaska Tsunami Warning Center, who received the report from a resident of Karluk Village on Kodiak Island.  Using a spotting scope, the village resident had observed the peaks for the previous three weeks - noting no unusual activity - when on the morning of the 11th he witnessed a sudden increase in steam activity and watched as white, towering steam clouds billowed from Martin, subsided, and then rose again to about 600-700 ft (~200 m) above the vent, forming a large mushroomed top before dissipating.  A second white, billowing steam plume then rose from adjacent Mageik.  Local pilots also noticed the unusually vigorous activity.\"\r\n   Miller and others (1998) state that these events do not constitute a volcanic eruption.","StartYear":1997,"StartMonth":12,"StartDay":11,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1997,"EndMonth":12,"EndDay":11,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Martin","ParentVolcano":"Martin","VolcanoID":"ak189","ParentVolcanoID":"ak189"},{"ID":584,"Name":"Akutan unrest 1998/3","Description":"   From McGimsey and others (2003): \"On March 26, 1998, AVO received phone calls from the Trident seafood processing plant in Akutan reporting lighting and a possible steam cloud over the summit of the volcano [Akutan].  At the same time, an increase in high-frequency seismicity was detected.  The tremor-like seismic signal was confined to a single station.  A strong storm with high winds was passing through the region and AVO ultimately concluded that the seismic signals were weather-related.\"","StartYear":1998,"StartMonth":3,"StartDay":26,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":79,"Name":"Korovin 1998/6","Description":"   From McGimsey and others (2003): \"On the morning of June 30, 1998, AVO received a call from the Village Public Safety Officer (VPSO) in the village of Atka with a report of a dark ash cloud rising to 30,000 feet. The VPSO had observed two separate clouds, the first at approximately 07:30 local (Hawaii-Aleutian Time Zone is one hour behind ADT) and the second at approximately 08:30 local. The second cloud was the larger of the two reaching an estimated 30,000 ft and tinted orange 'as if illuminated from within', according to another observer in Atka. At 11:15 local, AVO received a pilot report from a USCG C-130 aircraft in the vicinity who noted an apparent volcanic cloud reaching about 16,000 feet ASL. At 17:20 local, AVO received a United Airlines pilot report of a cloud to 30,000 feet near the volcano. Coincident satellite imagery did not show an obvious volcanic cloud, however a plume-like meteorologic cloud was evident. The Atka VPSO stated further that both events produced dustings of ash in Atka, the first coarser grained than the second. AVO also learned that an individual had observed a dark ash plume over Korovin two days earlier on June 28. In addition, a commercial pilot very familiar with the volcanoes in the Aleutians contacted AVO to report his mid-May observation of the 'southeast slope blackened by ash' during a fly-by on May 10. He had not seen this during the previous week and speculated that it had occurred only a few days prior to May 10 because of weather conditions and wind directions. Thus, the timing of this activity remains poorly constrained; intermittent ash emission may, in fact, have occurred for weeks or prior to June 30.\r\n   \"AVO conducted a call-down after receiving the initial report from Atka and solicited pilot reports from the FAA. FAA officials issued a Significant Meteorological Information statement (SIGMET), a Temporary Flight Restriction (TFR) around the volcano (20 mi radius from sea level to 25,000 ft) and decided to route aircraft well to the north of Korovin. The Atka Pride Seafood processing plant was closed for the day out of concern for the effects of ash on workers and the quality of fish. Reeve Aleutian Airways had an airplane en route from Dutch Harbor to Adak when the late afternoon pilot report of a cloud to 35,000 feet was received. Based on the report, the Reeve plane returned to Dutch Harbor. The Marine Radio Operator issued an ash advisory to mariners in the vicinity of Atka.\r\n   \"Over the next several days, poor weather largely precluded any good views of the volcano. One Atka observer reported a 'rusty' cloud estimated to reach 16,000 feet ASL moving southeast from the volcano on the evening of July 2. On July 3, a pilot familiar with the volcano reported profuse steaming from the summit crater, typical of the past few months (cover photo). He noted new ash on the south, southeast, and east flanks. A thin trail of ash extended to the southwest, towards the village of Atka. On July 8, AVO noted minor, weakly ash-bearing clouds over Korovin on Advanced Very High Resolution Radiometer (AVHRR) satellite images. On July 10, Environment Canada contacted AVO to relay a pilot report of a possible ash cloud over the general vicinity of Vancouver Island; a number of SIGMETs and other official notices were released. Several additional pilot reports of possible ash were logged by Canadian aviation authorities who also recorded many aircraft diversions in Canadian airspace. It remains possible that this cloud was related to an undetected Korovin eruption several days prior to the pilot report. A more likely scenario, however, is that smoke from numerous fires in the heavily forested area of western Canada and even Siberia generated a far-traveled haze mistaken for volcanic ash (Little and others, 1999).\r\n   \"Over the course of this episode of unrest, AVO issued Information Releases on June 30 and July 1, and mentioned Korovin in the Weekly Updates of July 3 and July 10.\"","StartYear":1998,"StartMonth":6,"StartDay":30,"StartTime":null,"StartQualifier":1,"StartQualifierUnit":"Months","EndYear":1998,"EndMonth":6,"EndDay":30,"EndTime":null,"EndQualifier":7,"EndQualifierUnit":"Days","Volcano":"Korovin","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak171","ParentVolcanoID":"ak17"},{"ID":416,"Name":"Augustine 1998/7","Description":"   McGimsey and others (2003) consider the 1998 activity non-eruptive : \"On July 12, 1998, charter pilots from Homer who routinely fly by Augustine noted fingers of mud up to about 250 ft wide (76 m) extending down from the cloud-enshrouded summit to snowfields on the upper north-northeastern flank. Other snowfields near the summit were discolored by fine gray ash deposits. One particular flow of pinkish muddy material had reached the sea. AVO received this information on July 13 and immediately canvassed the seismic, tiltmeter, and temperature sensor data for the previous several days. Rockfall and small avalanches are a common, if not everyday, occurrence on Augustine and have recognizable seismic signatures. The seismic records for July 10 showed a larger than usual avalanche event at 21:23 ADT that lasted at least 30 seconds. On July 14, the same charter pilots flew by Augustine - this time during clear weather - they reported that a portion of the spine that was extruded from the summit dome in 1986 (see figure 5 in original text) had collapsed and was the apparent source of the small mudflows observed several days earlier. They also reported that the volcano seemed to be steaming more than usual. AVO geophysicist John Power measured fumarole temperatures near the base of the toppled spine later in July and reported temperatures of 93.8 and 96.9oC, similar to those measured in 1997.\"","StartYear":1998,"StartMonth":7,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":340,"Name":"Shrub 1998/7","Description":"   Staff from the Alaska Volcano Observatory visited Shrub on July 31, 1998, and reported \"The level of activity remains high.  Total amount of mud production at the volcano is probably about the same as in August, 1997.  However, production at the main vent area [see fig. 4 in original text] is considerably less than the rate observed in 1997.  A very noticeable change is the nature of the eruptive activity.  The violent discharge of mud and gas that was typical of the 1997 activity was not observed during this visit.  Rather all presently active vents were quietly discharging mud and gas from bubbling mud pools or ponds.  Temperatures as high as 49.9 degrees C - more than 2 degrees C higher than those of June and August 1997 - were measured (McGimsey and others, 2003).\"\r\n   From McGimsey and others (2004): The eruption of Shrub mud volcano continued throughout 1999. \"Shrub mud volcano was visited on June 23 and 24, 1999 as part of an informal joint National Park Service (NPS) and U.S. Geological Survey project to monitor the activity that began in the spring of 1997. All of the known vent areas were visited and remapped. Temperature of the mud was measured at numerous vents, [see fig. 5 in original text], CO2 discharge was determined for several vents, diffuse CO2 flux in the soil was measured in a grid section, and several new vents were discovered and documented (Sorey and others, 2000). As in 1998, all of the active vents were quietly discharging mud and gas from bubbling mud pools or ponds. Temperatures as high as 54°C (5-7°C higher than those recorded in June 1998) were measured (Sorey and others, 2000). Surprisingly, several new vents were discovered that were discharging mildly turbid water at ambient temperatures (9.5-14°C). The new vents were located only a few meters away from those discharging highly turbid, warm water (48°C). All vents, regardless of mud content and temperature, were discharging gas comprised 98% CO2. An estimated 10 metric tonnes of CO2 per day is discharging from spring vents on Shrub, and along with measured concentrations of bicarbonate, a total CO2 upflow from depth of 20-40 metric tonnes per day was estimated by Sorey and others (2000). Measurements of diffuse degassing rates from soil in an area of recent vegetation kill indicated high CO2 concentrations in the root zone (26% CO2 at 10 cm depth). Several small, dead animals near the vents and newly killed vegetation were indicative of the continuing CO2 hazard at Shrub.\r\n   \"More than 500,000 m3 of mud have been erupted since activity began in the spring of 1997 (Richter and others, 1998, OF 98-128). New aerial photography flown on August 14, 1998 was used to more precisely map the extent of mud deposits and main vent locations [see fig. 5 in original text; after Richter and others, 1998; addendum to OF 98-128). The extent of mud deposits in 1999 was largely the same as in 1998.\"\r\nActivity similar to that observed in 1999 continues at Shrub to the present (2015).","StartYear":1998,"StartMonth":7,"StartDay":31,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1999,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shrub","ParentVolcano":"Klawasi Group","VolcanoID":"ak253","ParentVolcanoID":"ak163"},{"ID":390,"Name":"Shishaldin 1998/11","Description":"   From McGimsey and others (2003): \"On November 4, 1998, AVO received word from the U.S. Coast Guard (USCG) of a possible ash plume above the summit crater of Shishaldin Volcano.  The report reads, 'Ash and smoke extending up to 100 ft above volcano vent; dark in color.  Puffs approximately 10 minutes apart.'  This type of activity is typical of Shishaldin and probably reflects a continuing high-level heat source and intermittent phreatic explosive activity within the summit crater.\"","StartYear":1998,"StartMonth":11,"StartDay":4,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":508,"Name":"Vsevidof 1999/1","Description":"   From McGimsey and others (2004): \"On January 28, a resident in Nikolski on Umnak Island called at 4 pm AST to report 'black smoke, dark puffing' issuing from the top of nearby Vsevidof Volcano. The weather was cold and clear, and a M6.1 regional earthquake had occurred in the area the previous evening, followed by numerous aftershocks.\r\n   \"AVO received no additional or subsequent reports of activity. Routine examination of satellite data by AVO remote-sensing specialists earlier in the week revealed that indeed a minor steam plume was present at the volcano. The wintertime low sun-angle likely accounts for the reporter's description of 'black smoke'.","StartYear":1999,"StartMonth":1,"StartDay":28,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Vsevidof","ParentVolcano":"Vsevidof","VolcanoID":"ak307","ParentVolcanoID":"ak307"},{"ID":391,"Name":"Shishaldin 1999/2","Description":"   From McGimsey and others (2004): \"During the summer of 1998, the volcano became seismically restless. Activity slowly escalated and culminated in a subplinian eruption on April 19, 1999 that placed an ash cloud to 45,000 ft ASL (~13,700 m). The eruption style almost immediately changed to that of vigorous strombolian fountaining (Nye and others, 2002), which characterized the activity for the following six weeks.  AVO closely monitored the activity using seismic data, daily imagery from weather satellites, rare local ground and aerial observations, and an airborne thermal instrument. The eruption was deemed over in the last few days of May.\r\n   \"* * * At 10:14 AM AST on January 7, 1999, a shallow, M1.4 earthquake was recorded under Shishaldin Volcano (Jolly and others, 2001). On January 9 at 5:55 PM AST, AVO received a call from National Weather Service (NWS) personnel in Cold Bay reporting that a larger than usual steam plume with possible ash at the base was rising from Shishaldin Volcano to an estimated 10,000 to 15,000 feet ASL and extending several tens of kilometers to the northeast. No anomalous seismicity was occurring and the activity was not visible on Advanced Very High Resolution Radiometer (AVHRR) satellite imagery from 0113Z and 0222Z. A follow-up report from NWS at 6:40 PM AST indicated that the steam plume was somewhat diffuse but still more voluminous than usual.\r\n   \"On February 2, AVO seismologists noted a high level of tiny seismic events occurring beneath the volcano. NWS personnel in Cold Bay reported seeing a 'good plume' at Shishaldin on February 9 rising 5,000-6,000 ft. above the vent and trailing to the south. A weak thermal anomaly was also observed on this date. Steaming continued for the next couple of days and a one-pixel thermal anomaly was visible in the AVHRR 1715Z satellite image on February 12. Shishaldin was clearly restless, and AVO announced the activity in the weekly update that morning (Friday, Feb. 12) and warned that while a thermal anomaly persisted, there was a chance of a sudden, low-level ash burst. A pilot reported a steam plume rising 9,000 ft. above the vent on the morning of February 18; this was corroborated by a NWS observer in Cold Bay. AVO seismologists determined on this date that low-level but continuous seismic tremor was occurring at the volcano. This, and the persistence of a thermal anomaly prompted AVO to raise the Level of Concern Color Code from GREEN to YELLOW at 3:15 PM AST (0015 UTC) on Thursday, February 18. [See Table 5 in original text for an explanation of the Level of Concern Color Code.]\r\n   \"Steam activity seemed to wane for the next several weeks. On March 4, a shallow M5.2 earthquake struck 9 miles (14 km) southwest of Shishaldin (Moran and others, 2002). NWS observers in Cold Bay reported that on March 5 the summit crater rim of the volcano was snow-free -- an indication of increased heating of the summit; no ash was present on the snow-covered upper flanks. On March 8, AVO reported that the summit vent thermal anomaly had increased over the weekend, seismic tremor was continuing, and that an ash burst could occur with little or no warning.\r\n   \"During the next three weeks -- when weather permitted a view -- NWS observers in Cold Bay reported that no steam plume was present but the upper flanks were snow-free. The summit vent thermal anomaly persisted, as did low-level seismic tremor. On April 2, a pilot confirmed the snowmelt at the summit.\r\n   \"After nearly two and a half months of precursory activity strong seismic tremor began on April 7 at about 8:00 AM ADT (1600 UTC). AVO raised the Level of Concern Color Code to ORANGE and warned that an explosive ash burst or lava eruption could occur over the next several hours or days. By that afternoon, although the strong seismic tremor had subsided, the Color Code was held at ORANGE and AVO began a 24-hour monitoring effort, which would last until June 18, 1999.\r\n   \"On April 12, with seismicity back down to somewhat-above-background levels since April 7, AVO reduced the Level of Concern Color Code to YELLOW; the summit vent thermal anomaly persisted. Then, late on the night of April 13, seismic tremor increased significantly following a M4.5 earthquake and aftershocks that occurred west of the volcano. AVO raised the Color Code back up to ORANGE the following afternoon, April 14.\r\n   \"Seismic tremor levels began to steadily increase on April 17. On this day, an AVO scientist accompanied the Alaska State Troopers in their Forward-Looking-Infrared-Radiometer (FLIR)- equipped twin-engine aircraft on a flight down the Alaska Peninsula. Although a steam cloud obscured the summit area of Shishaldin, FLIR images revealed that energetic strombolian fountaining was occurring with blocks and spatter hurled up to 600 feet (~200 m) within the vent [see figs. 9, 10 in original text]. NWS observers and a ship's crew offshore reported that snowmelt had run partway down the northwest flank.\r\n   \"At 11:33 AM ADT (1933 UTC) on April 19, seismic tremor amplitudes dramatically increased and at 11:45 AM a pilot reported seeing a steam and ash plume that rose to 30,000 ft (~9,150 m). AVO raised the Color Code to RED at 12:15 PM ADT (2015 UTC) and announced that a significant eruption was in progress. By early afternoon the plume had reached 45,000 ft (~13,700 m).\r\nSatellite data suggests that the plume reached a maximum height of about 56,000 ft. (17,000 m) (Dave Schneider, oral communication). Ash was dispersed southward at higher altitudes and northward at lower altitudes [See fig. 11 in original text].\r\n   \"The eruption lasted about 7 hours, and by 11 PM on April 19, seismic tremor had substantially decreased although strombolian eruptive activity likely continued based on seismicity. A further abrupt and significant decrease of seismicity in the early morning hours of April 20 indicated that explosive activity had subsided, prompting AVO to lower the Color Code to ORANGE. A thermal anomaly persisted in the summit crater. However, about 4 PM ADT (0000 UTC) on April 20, seismic tremor began to increase again and strengthened about 11 PM ADT (0700 UTC). By midmorning on April 21, seismicity was back up to levels similar to that in the hours prior to the explosive eruption on April 19 prompting AVO to raise the Color Code to RED at 11:15 AM ADT (1915 UTC) and issue a warning that a moderately strong strombolian eruption was likely occurring and that a significant explosive event could occur at any time. Satellite imagery on this day revealed no major ash cloud but a very large thermal anomaly was visible through the night; lava fountaining to a few hundred feet above the summit was observed along with occasional steam and ash clouds under 15,000 ft. (~4,600 m).\r\n   \"An explosive eruption was not forthcoming and on Thursday morning, April 22, although seismicity continued to fluctuate, the overall level had decreased from that of the previous morning.  AVO lowered the Color Code to ORANGE at 10 AM ADT (1800 UTC) April 22. AVO personnel flying with the Alaska State Troopers late that afternoon observed low-level strombolian activity.  Seismicity soon began to increase and by 9 PM ADT (0500 UTC), based on rapid increase of tremor levels, an explosive eruption began prompting AVO to again elevate the Color Code to RED (9:50 PM ADT, 0550 UTC, April 22). The tremor signals that occurred during the eruptions of Shishaldin Volcano on April 19 and 23 were the strongest ever recorded in the Aleutian Arc by AVO in its 11-year history (Thompson and others, 2002).\r\n   \"About 4 hours later, seismic tremor rapidly diminished heralding an end to this eruptive event. Later that morning AVO reduced the Color Code to ORANGE (7:50 AM ADT, 1550 UTC, April 23). The size of the summit thermal anomaly indicated the continuance of low-level strombolian activity, although no ash clouds were visible on satellite images. Seismicity continued to be relatively low throughout the day. An AVO observer aboard the State Troopers plane documented a short-lived, mildly explosive ash burst that rose to about 15,000 ft ASL (~4,600 m) [See cover of original document]. Also observed was that the flanks were mantled with ash, mudflows, and probable spatter-fed lava flows from earlier eruptive activity [See figure 12 in original text].\r\n   \"For the next two days, occasional strombolian eruptions occurred—based on continuation of relatively low seismicity and persistence of the summit thermal anomaly—and on the morning of April 26, a fishing vessel located 40 miles east of the volcano reported light ashfall. Satellite data confirmed a narrow plume extending for more than 100 mi (161 km) to the northeast and a weak summit thermal anomaly. By April 28, seismicity had declined to levels that indicated that eruptive activity was not likely occurring, no ash clouds had been observed in the past 2 days, and the summit thermal anomaly, which had persisted since early February, was not present on clear satellite images. AVO responded by lowering the Color Code to YELLOW but warning that eruptive activity could resume with little or no warning.\r\n   \"Nothing much changed until the night of May 12 when a weak thermal anomaly appeared on a GOES satellite image and weak seismic tremor was recorded. The following morning, May 13, the crew of a NWS boat at the north end of False Pass observed a small steam and ash burst (~10:25 AM ADT, 1825 UTC). A PIREP at 11:15 AM ADT (1955 UTC) confirmed a small plume that rose to about 1,000 ft (300 m) above the summit. A weak thermal anomaly and lowlevel seismic tremor continued for the next 10 days. Then, late in the evening of May 24 (11:11 PM ADT, 0711 UTC), a PIREP indicated that a plume was present to about 20,000 ft. ASL (6,100 m) above the volcano. Satellite data at 6:59 AM ADT (1459 UTC) on the following morning revealed a narrow, ash-rich steam plume extending 100 miles (161 km) south from Shishaldin at an altitude of about 15,000 ft. ASL (4,600 m). Low to moderate levels of seismicity continued.  AVO raised the Color Code to (9:30 AM ADT, 1730 UTC, May 25) and announced that low-level steam-and-ash eruptions and ash bursts were occurring at the volcano.\r\n   \"For the next several days, narrow, ash-rich plumes were observed via satellite emanating from the volcano and seismicity indicated that short-lived, low-level steam and ash explosions were occurring.  A small thermal anomaly persisted. Satellite images on May 28 revealed no evidence of ash plumes or a thermal anomaly and the seismicity declined. An AVO field crew working on the north flank of the volcano reported that only white steam was rising from the summit crater. The lowered level of seismicity and the absence of ash plumes and a thermal anomaly prompted AVO to decrease the Color Code to YELLOW on June 1. This effectively marked the end of the 1999 Shishaldin eruption. The seismicity remained just slightly above normal background levels for the next several weeks and no plumes or thermal anomalies were present. Activity at the volcano had returned to 'normal', that is, a nearly continuous low-level steam plume, non-tremor micro-seismicity associated with minor phreatic activity. AVO reduced the Level of Concern Color Code to GREEN on Friday, June 18 (the 14th Color Code change of the eruption, see Table 3 in original text), and ended its 24-hour-a-day surveillance of the volcano. The AVO weekly update of volcano activity in Alaska dropped Shishaldin as a feature on Friday, June 25, 1999.\r\n   \"In addition to local minor ash dustings, the eruption produced minor mudflows down the flanks [See figure 12 in original text], a significant ash deposit on the south flank, and a lahar deposit down the north flank [See figure 13 in original text]. The lava produced in this eruption of Shishaldin is evolved basalt of about 49% SiO2 (Nye and others, 2002).\"\r\n   Stelling and others (2002) estimate a total tephra volume of 4.7x10^7 cubic meters, with a Dense Rock Equivalent (assuming solid rock density of 2,600 kg m^-3) of 1.4x10^7 cubic meters.\r\n   For detailed chronologic tables of the events in this eruption, see Nye and others (2002) or McGimsey and others (2004).","StartYear":1999,"StartMonth":2,"StartDay":9,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":1999,"EndMonth":5,"EndDay":28,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":506,"Name":"Wrangell 1999/5","Description":"   From McGimsey and others (2004): \"On the morning of May 14, 1999, a NWS observer in Gulkana reported anomalous steam - with minor ash - emission at Wrangell Volcano. At approximately 9:30 AM ADT, a sudden, rapidly billowing, grayish and white cloud rose to about 3,000 feet above the north summit crater. The weather was clear with calm winds out of the south. The observer stated that at this time of year, on clear days, a small, wispy, steam plume is usually visible above Wrangell in the early morning, and dissipates by early afternoon. On this day, the plume developed quickly, was abnormally voluminous, and had a grayish color.\r\n   \"We learned from interviewing a local pilot (Lin Ellis), flying a routine mail run, that he had also observed the activity at Wrangell while passing by the south-southwest flank at 10,000 feet ASL.  Additionally, he noticed that more 'dirt' surrounded the north crater than usual, and, that on the upper part of the Chestnina Glacier - high on the southwest flank - blocks of ice were chaotically\r\n jumbled (higher relief between blocks) and that the glacier surface was much more crevassed than he had ever previously seen. He also observed that of two known fumaroles located at about the 11,000-foot level (3,350 m) on the south flank that typically issue steam through ice holes, one was now surrounded by a sizeable patch of bare rock. This, too, was a new development since his\r\nlast recent flight over the area. Ellis further reported that he had seen no sign of flowage or melting events (high on flank), but that he had not flown over the lower reaches of the glacier.\r\n   \"As of 5 PM, the NWS observer in Gulkana could still see a small steam plume and with binoculars could see that the snow around the summit area appeared to be light gray and that this was a definite color contrast and not an effect from shadows. AVO conducted follow-up phone calls to confirm that activity had returned to 'normal'.","StartYear":1999,"StartMonth":5,"StartDay":14,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":1999,"EndMonth":5,"EndDay":14,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Wrangell","ParentVolcano":"Wrangell","VolcanoID":"ak326","ParentVolcanoID":"ak326"},{"ID":585,"Name":"Iliamna 1999/7","Description":"   From McGimsey and others (2004): \"On July 6, 1999, AVO received a message from the FAA Center Weather Support Unit that a pilot had reported a fresh flow of mud and rock from the upper northeast flank of Iliamna.\r\n   \"Iliamna is an erosionally dissected ice- and snow-covered stratocone that lies 225 km southweast of Anchorage in the Aleutian Range.  No historical eruptive activity has been documented, however, a prominent fumarole field near the summit produces a nearly constant steam plume, which is often mistaken for eruptive activity.  The fumaroles high on the south and east-northeast flanks occur where large scars reveal that most of the upper edifice consists of highly altered, unstable rock.  The eastern scar has been the source of frequent non-volcanic gravitational collapses that produce mixed avalanches of ice, snow, rock, and mud that typically extend several kilometers down the flank; some are large enough to be visible from the Kenai Peninsula (Neal and others, 1995; McGimsey and Wallace, 1999).\"","StartYear":1999,"StartMonth":7,"StartDay":6,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":507,"Name":"Pavlof 1999/7","Description":"   From McGimsey and others (2004): \"An AVO remote-sensing specialist on a commercial flight from Cold Bay to Anchorage on July 13, 1999 noted that the summit of Pavlof was snow-free and that the upper, snow-covered north flank appeared 'dirty'. A pilot reported on July 30 'ash to 5,000 feet [presumably above the summit] - no eruption'. Seismic and satellite data indicated no unusual activity. NWS personnel suggested that strong winds in the area were remobilizing ash deposits on the upper flanks and summit. Steam plumes from the summit were visible from Cold Bay on several occasions.\"","StartYear":1999,"StartMonth":7,"StartDay":13,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":586,"Name":"Veniaminof 1999/7","Description":"   From McGimsey and others (2004): \"On July 30, 1999, AVO received a report from an Alaska Department of Fish and Game (ADF\u0026G) biologist working at a fish weir on the Chignik River that the West Fork was unusually turbid.  An ADF\u0026G pilot also reported that an abnormal amount of water was discharging from the termini of the glaciers feeding this river, which originate on the east and northeast flanks of Veniaminof Volcano.  The biologist and pilot -- both experienced in the area -- had never before seen this level of discharge and extreme turbidity in the river and were concerned about potential adverse effects on fish.  They reported that no unusual steaming or other activity was visible form their camp.  There were no further reports.  AVO had no seismic instruments on this volcano in 1999.\"","StartYear":1999,"StartMonth":7,"StartDay":30,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Veniaminof","ParentVolcano":"Veniaminof","VolcanoID":"ak301","ParentVolcanoID":"ak301"},{"ID":392,"Name":"Shishaldin 1999/9","Description":"   From Neal and others (2004): \"Following anomalous, post-eruption seismicity of late December 1999, a series of seismic events caused by small explosions were identified on January 15, 2000. No associated plumes or thermal anomalies appeared on satellite images. Re-analysis of seismic data for the previous several months revealed that similar small 'explosion' seismic signals had been occurring intermittently since September 1999, several months after the end of the main phase of the 1999 eruptive activity (Nye and others, 2002). The January events were low-level and difficult to discern during the frequently inclement weather when background noise was high. The explosions prompted AVO to mention the change in the weekly update, however, the level of concern color code remained GREEN (table 4.) On January 28 and 29, vigorous steam plumes were observed rising up to about 3,000 ft (1,000 m) over Shishaldin. By early February, the frequency and amplitude of the overall seismicity, including the explosion events, had increased (up to 200 per day) and were accompanied by reports of vigorous steam plumes. The activity was interpreted to be small phreatic explosions within the cone's deep central crater. Noting that a similar pattern had developed in February 1999 prior to the onset of strombolian eruptive activity, AVO upgraded the color code to YELLOW on February 3. Fortuitously, the number of seismic events abruptly decreased the next day.  The color code was lowered to GREEN on February 18. A small steam plume was observed in satellite images on February 22 that extended 15-20 km (9-12 mi) east of the volcano, and small, low-frequency seismic events continued through the spring.\r\n   \"Satellite analysis detected a few weak thermal anomalies in the summit crater through the spring and summer of 2000. On occasion, steam plumes extended up to 15 km (9 mi) from the summit.  In early May, a significant increase in the number of small, low-frequency earthquakes was recorded, however no attendant change in thermal character or visual observations was noted, and\r\nseismicity declined by the end of summer. AVO mentioned both the seismicity and thermal anomalies in weekly updates for a period of one month, but remained at Level of Concern Color Code GREEN for the remainder of the year.\"","StartYear":1999,"StartMonth":9,"StartDay":25,"StartTime":null,"StartQualifier":10,"StartQualifierUnit":"Days","EndYear":2000,"EndMonth":2,"EndDay":4,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":510,"Name":"Snowy 2000","Description":"   From Neal and others (2004): \"In mid-September 2000, AVO received a pilot report of a steam plume emanating from a depression in the surface of the upper Aguchik Glacier about 3 mi (5 km) SE of the summit peaks of Snowy Mountain * * * According to the pilot, Kodiak Air Service owner Willy Hall, this was the first time in his many years flying the region that he had seen either the depression or the accompanying steam. Hall also reported a strong sulfur smell while in the vicinity.\r\n   \"At AVO's request, NPS Unit Manager and pilot John Bundy photographed the area from the air on September 29 and again on October 8 [see fig. 4 in original text]. The anomalous depression is roughly circular in shape, several hundred meters in diameter, and marked by concentric, nested crevasses that enclose a steep-walled opening of unknown depth. The crevassed ice defining the depression slopes towards the hole with increasing severity until nearly vertical ice-walls define the opening, also roughly circular in shape. Based on crude estimates of crevasse scale, we estimate the opening to be about 15-30 m (60-100 ft) across. This feature occurs on a portion of the icefield that flows generally to the southeast with a slope of about 8°; meltwater from this glacier eventually\r\ndrains into Kukak Bay. Geographic coordinates first reported by Willy Hall are 58°17.69' N, 154°38.78' W, placing the hole at an elevation of about 975 m (3,200 ft).\r\n   \"In Bundy's photos from both September 29 and October 8, a faint wisp of steam emerging from the orifice is visible. High winds and turbulence quickly dissipated the steam during the Bundy flights, but the original pilot report estimated the steam plume to rise 100-200 ft (30-60 m). Neither Bundy nor Hall observed other fumaroles in the area, including the nearby summit peaks of Snowy Mountain. Actively steaming fumaroles had been recorded at the highest Snowy peak in 1982 (Kienle and Swanson, 1983; Motyka and others, 1993), however, over the past several summers, USGS geologists Judy Fierstein and Wes Hildreth noted no sulfur smell or trace of fumarolic activity anywhere on the Snowy edifice.\r\n   \" * * * Based on several lines of evidence, the depression, central orifice, and minor, transient steam plume appear to be new features. We are not able to locate a similar structure on air photos from 1984 nor on Landsat images from 6 September 1999. It is uncertain exactly when the feature developed or became visible, however, based on Hall's comments, it was likely sometime during\r\nsummer 2000. The gradual 'sag' towards the central orifice indicated by crevassing patterns suggests the depression developed slowly (perhaps over years?) rather than suddenly during a rapid deformation or melting event that would have produced steep ice walls (John Paskievitch, pers. comm. 2000). On the other hand, the feature is quite similar in appearance to the 'subsidence\r\nbowl' that developed over eruptive vents at Vatnajokull, Iceland, in 1996.\r\n   \"AVO detected no significant change in background seismicity in the area over the course of the year, arguing against an intrusive event or significant acceleration of hydrothermal activity. However, the southeast Snowy edifice is not well-captured within the Katmai area seismic net and very small events may have gone undetected (John Power, pers. comm. 2003). It is possible that\r\nchanges in the surface of the glacier - retreat or other mass balance changes - have allowed an older feature to become more prominent at the surface.\"","StartYear":2000,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Snowy","ParentVolcano":"Snowy","VolcanoID":"ak257","ParentVolcanoID":"ak257"},{"ID":509,"Name":"Wrangell 2000/3","Description":"   From Neal and others (2004): \"AVO received word from a Trans Alaska Pipeline worker of an unusually strong, white steam\r\nplume from Wrangell between 0500 and 0600 AST on March 18, 2000. Later that day, a National Park Service employee in Kenny Lake reported robust steaming over the past month from multiple sources on the southwest flank of the volcano, between approximately 2,000-5,000 feet (600-1,500 m) below the summit. AVO found no anomalies in satellite imagery related in time to either report and concluded that no significant unrest had occurred.\"","StartYear":2000,"StartMonth":3,"StartDay":18,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Wrangell","ParentVolcano":"Wrangell","VolcanoID":"ak326","ParentVolcanoID":"ak326"},{"ID":156,"Name":"Makushin 2000/7","Description":"   From McGimsey and others (2004): \"On February 22, 2001, pilot Joe Polanco reported smelling sulfur and seeing steam issuing from the summit area of Makushin as he flew by.  Over the next several months, as tremor from the eruption of Cleveland volcano, 230 km (~145 mi) to the west was being recorded on the Makushin network, AVO seismologists began to suspect that some of the seismicity was actually being generated at Makushin.  By May, 2001, it was determined that a real increase in seismic activity beneath Makushin had begun in July, 2000, and on June 1, 2001, AVO included Makushin in the Weekly Update.  Earthquakes ranging in magnitude from 0 to 1.5 were occurring at a depth of between 0 and 8 km.  AVO continued to closely monitor the activity, which became intermittent by mid-summer and slowly faded back down to background levels through the fall months.\"","StartYear":2000,"StartMonth":7,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":2001,"EndMonth":6,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":393,"Name":"Shishaldin 2000/8","Description":"   From Smithsonian Institution (2000): \"The Alaska Volcano Observatory (AVO) reported on 11 August that recent satellite data indicated a weak thermal anomaly at Shishaldin's summit, although no known seismic activity occurred above background levels in the area. Pilot reports did not disclose any noticeable change in steam emission from the summit crater. Accordingly, the AVO decided to keep the Level of Concern Color Code for Shishaldin at Green.\r\n   \"After 11 August, clear days allowed unobstructed remote sensing, and satellite observations, which suggested no further thermal anomaly. On 18 August, AVO issued an update stating that new seismic data analysis showed several small explosions occurring coeval with the thermal anomaly reported on 11 August. These explosions were similar to those observed throughout 1999 and in early 2000 (Bulletin v. 24, nos. 2, 3, 4, and 8; v. 25, no. 2). The thermal anomaly and seismic disturbances did not recur in the remainder of August, however, so the hazard status remained Green.\"","StartYear":2000,"StartMonth":8,"StartDay":11,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":511,"Name":"Chiginagak 2000/12","Description":"   From Neal and others (2004): \"In late December 2000, Navigation Officer Daniel Karlson contacted AVO to report observations of steaming from Chiginagak Volcano in late July and early August during NOAA operations off the Pacific coastline of the Alaska Peninsula. By their estimate, the steaming emanated from a source at approximately 5,200 ft (1,580 m) on the north flank of the volcano, approximately the position of the well-known fumarole long described for Chiginagak. Karlson noted that the cloud was white and constant much of the time, with a few episodes of increased output that extended 'several miles' downwind. He reported that the activity appeared to diminish in intensity over time, ceasing altogether in early August.\"","StartYear":2000,"StartMonth":12,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Chiginagak","ParentVolcano":"Chiginagak","VolcanoID":"ak49","ParentVolcanoID":"ak49"},{"ID":518,"Name":"Kukak 2001","Description":"   McGimsey and others (2004) write that Willie Hall, a pilot with Kodiak Air Service, \"reported seeing about 15 vents [fumaroles] on Kukak Volcano, which he described as deep holes in the summit ice field, with most on the upper west flank and about 3 on the east side. In his 23 years of flying over the area he had never seen fumaroles on Kukak before. Wood and Kienle (1990) describe 'a vigorous fumarole field on Kukak's northern peak [that] keeps that area free of ice and reveals the volcanic character of Kukak.' A U.S. Coast Guard helicopter crew reported in June of 1997 seeing steam rising from several vents from a high peak northeast of Mt. Katmai, presumably on Kukak (McGimsey and Wallace, 1999).\"","StartYear":2001,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kukak","ParentVolcano":"Kukak","VolcanoID":"ak174","ParentVolcanoID":"ak174"},{"ID":522,"Name":"Frosty 2001","Description":"   McGimsey and others (2004) report that a rock fall was possibly mistaken for a volcanic eruption at Frosty during the summer of 2001.  Their report: \"AVO received several reports during the 2001 summer of possible eruptive activity at Frosty volcano. NWS observer in Cold Bay, Craig Eckert, took photos of what he described as an intermittent steam plume emanating from Frosty on July 8, 2001[See figure 8 in original text]. Inspection of records from nearby seismic networks revealed nothing unusual. Two days later, State Trooper pilot, Ron Kmiecik, reported atypical bare rock and dark material at the summit of Frosty, but no venting, steaming, or evidence of melting, specifically mentioning the absence of debris trails or channeling or melted snow. He described the material as a 'brown, rusty * * * not black and ashy like at Pavlof and Shishaldin, like red dust or crushed powder.' In the next several weeks, AVO received a couple of similar reports from local residents and pilots as well as inquiries about the possibility of impending volcanic activity. Craig Eckert reported on August 16 that on the previous day a strong sulfur smell enveloped Cold Bay when the wind was blowing from the southwest (i.e. from the direction of Frosty), and he sent additional photographs to AVO [See figure 9A-C in original text]. On August 28, 2001, AVO scientists working in the area flew over the volcano and observed nothing unusual and no indication of recent volcanic unrest. They noted that snow levels were uncharacteristically low - likely owing to the unusually warm summer - exposing the summit rocks for the first time in many years. The newly exposed rocks at the summit, and the possibility (likelihood) of minor rock fall avalanches may have been the cause for mistaken signs of volcanic unrest. They noticed no major landslide deposits, no unusual discoloration, and no sulfur odor.\"","StartYear":2001,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Frosty","ParentVolcano":"Frosty","VolcanoID":"ak105","ParentVolcanoID":"ak105"},{"ID":520,"Name":"Pavlof 2001/1","Description":"   McGimsey and others (2004) summarize 2001 steaming and other activity at Pavlof as follows: \"Principal/Teacher, John Concilius, has a good view of Pavlof from his home in Nelson Lagoon. On January 20, 2001 he observed through binoculars steaming from multiple locations near the summit, but none actually at the top of the volcano. He reported that the steam was white and not discolored, and, that the snow near the summit was clean with no evidence of melting.\r\n   \"He concluded by stating that this was the most steaming he had seen at the volcano during the past several years and that other villagers considered the steaming to be unusual.AVO remote sensing specialist Dave Schneider analyzed Advanced Very High Resolution Radiometer (AVHRR) satellite images taken from January 18 to 22, 2001 and found no evidence of increased thermal activity at the volcano and no unusual seismicity was noted. No further reports of steaming were forthcoming. This may have been a meteorological phenomenon.While working in Cold Bay in early June, Martin LaFevers, Seismic Data Manager at UAFGI, observed and photographed the summit of Pavlof during a weather break; it appeared to be covered with ash. A local pilot reported seeing 'something other than steam' at the summit. Again, there was no indication of anomalous seismicity.\r\n   \"NWS observers in Cold Bay contacted AVO on the morning of November 7, 2001 to report a small steam plume originating from the south side of Pavlof; they also received several Pilot Weather Reports (PIREPS) describing the same observation. About a month later, on December 13, 2001, NWS personnel in Cold Bay reported steam issuing from a point about half-way down the south flank of the volcano. The plume rose to a height of about 6,000 ft (~1,830 m) before dissipating. A Pen Air pilot corroborated the report and added that the steaming was coming from a 'hill' on the southwest flank; this pilot added that he encountered a strong sulfur smell on a flight by the volcano that day. AVO detected no unusual seismicity or thermal anomalies. Based on conversations with the Pen Air pilot, AVO determined that the source of steaming was likely the fumarole field on nearby Mt. Hague, a late Pleistocene volcano with no historic activity.\"","StartYear":2001,"StartMonth":1,"StartDay":20,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2001,"EndMonth":12,"EndDay":13,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":525,"Name":"Great Sitkin 2001/2","Description":"   McGimsey and others (2004) report anomalous seismicity at Great Sitkin during 2001: \"Beginning in early February, 2001, seismicity at Great Sitkin volcano began to increase. The activity came to an abrupt end by the end of the month. The next seven months was characterized by short-lived seismic swarms that ended as quickly as they began, most only a day or two in duration. The largest swarm (15 events) occurred on Saturday, August 18, 2001.\"","StartYear":2001,"StartMonth":2,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2001,"EndMonth":9,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":303,"Name":"Cleveland 2001/2","Description":"   From Dean and others (2002): \"Mt. Cleveland erupted explosively on 19 February and on 11 and 19 March 2001.  \r\n   * * * \"The first indication to AVO of activity at Mt. Cleveland was the 19 February eruption.  However, after the eruption, AVO received reports indicating that precursory activity had taken place.  Most graphic was a photograph taken on 2 February by a pilot flying by the volcano showing a dark, lobate deposit on the snow-covered southwest flank and robust steaming from the summit crater.  During this same period, residents of Nikolski observed steaming at the summit and snowmelt on the flanks of the cone.\r\n   \"On 19 February, Mt. Cleveland erupted explosively at approximately 1430 UT.  Pilot reports indicate that the altitude of the plume increased with time from 7.5 km a few hours after the start of the eruption, and up to 12 km eight hours later.  The eruption cloud and a thermal anomaly were detected on AVHRR satellite data at 1655 UTC.  The plume was complex and extended in two directions, 40 km northwest and 60 km southeast of the volcano. \r\n   * * * \"By 21 February (0300 UT), 35 hours after the eruption, the ash cloud was over 1000 km long and extended from Cook Inlet, Alaska, to Chukotsk Peninsula, Russia.  Eventually this long, arcing cloud split into three segments that drifted north over the Arctic Ocean, over Fairbanks near the center of the state, and south into the Gulf of Alaska.\r\n   * * * \"Mt. Cleveland erupted again on 11 March.  This explosive eruption lasted 3 hours (1400 to 1700 UT) based on satellite observations, with an estimated cloud height of 8 km.\r\n   * * * \"The 19 March eruption lasted up to 6 hours (2330-0530 UT), with an estimated cloud height of up to 9 km according to the National Weather Service.\r\n   * * * \"Throughout March and April, elevated surface temperatures and low altitude ash clouds were periodically observed on satellite data.  Ground and air observers noticed minor ash clouds over the volcano during the same period.\r\n   * * * \"Despite the extensive area traversed by the February plume, ash fall was observed only at Nikolski over a period of approximately 5 hours on 19 February.  Residents reported that the ash fall occurred under a hazy sky and consisted of a very light dusting of fine-grained material.  School children in Nikolski were given paper masks to wear home and residents were advised to stay indoors.  No injuries or health impacts have been reported; one resident noted that breathing outside without a mask 'made you want to cough.'\r\n   \"A sample from Nikolski shows that the ash is composed of glass shards, crystals, and lithics.  * * *  The glass is dacitic and has a magmatic morphology rather than phreatomagmatic.\"\r\n   Smith (2005), estimates a total erupted volume of deposits (not including tephra) from January through late March 2001 as 1.12 x10^6 cubic meters (+/- 3.07x10^5 cubic meters).","StartYear":2001,"StartMonth":2,"StartDay":2,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":2001,"EndMonth":4,"EndDay":15,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":178,"Name":"Okmok 2001/5","Description":"   McGimsey and others (2004) report on an earthquake swarm detected May 11, 2001, at Okmok Volcano: \"At 8:00 ADT (16:00 UTC) on the morning of May 11, 2001, AVO seismologists detected on the Makushin seismic network a swarm of earthquakes occurring under Okmok volcano prompting AVO to release an Update at 17:00 ADT (01:00 UTC). The events were ML=2.0-3.6 - too small to be felt by nearby residents - and determined to be possibly of volcanic origin. Satellite observations revealed no volcanic activity nor thermal anomalies. On-going satellite-based deformation measurements (SAR interferometry) show that the center of the caldera has inflated 20 cm between the 1997 eruption and September 2000. In April, 2001, AVO scientists observed an area of snowmelt in the caldera; although possibly indicative of heat flux, the area corresponded to the thickest part of the 1997 lava flow, which may still be hot (Patrick and others, 2003). By May 15, 2001, the earthquake swarm had greatly diminished. Okmok was last mentioned in the May 25, 2001 AVO Weekly Update.\"","StartYear":2001,"StartMonth":5,"StartDay":11,"StartTime":"08:00:00","StartQualifier":null,"StartQualifierUnit":"","EndYear":2001,"EndMonth":5,"EndDay":15,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Okmok","ParentVolcano":"Okmok","VolcanoID":"ak206","ParentVolcanoID":"ak206"},{"ID":523,"Name":"Shishaldin 2001/6","Description":"   Shishaldin Volcano experienced some seismic unrest and a possible steam plume during 2001.  McGimsey and others (2004) report: \"AVO detected that seismic activity began increasing at Shishaldin Volcano in early June, 2001 and continued through about the end of November, 2001. On April 26, 2001, a pilot reported a steam cloud rising to about 2,000 ft. (~600 m) above the summit. Although the Color Code status of the volcano was never raised above 'GREEN', and the restlessness was not reported in any of our weekly updates, AVO seismologists and remote sensing specialists maintained a close watch on the activity.\"","StartYear":2001,"StartMonth":6,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2001,"EndMonth":11,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":517,"Name":"Snowy 2001/6","Description":"   McGimsey and others (2004) summarize this event as follows: \"On June 27, 2001, Willie Hall of Kodiak Air Service called to report his observations of the 'steaming hole' in the glacier midway down the south flank of Snowy Mountain. Mr. Hall was the source for the first observations of the steaming hole in September, 2000 (Neal and others, 2004) [see figs. 4 and 5 in original text]. Hall reported that he flew over the area in late May/early June, 2001 using the coordinates previously established and could find no evidence of the hole. Keith Echelmeyer (UAF/GI glaciologist) conducted airborne glacier surveying in the Katmai region in early May and he, too, used the coordinates to examine the area where the hole was reported. He observed that the hole was still there, but 'not a big deal * * * not steaming and mostly snow-filled' [see fig. 6 in original text].\r\n   \"Hall also reported that he noticed a recent change at the snout of the glacier that contained the hole, where the melt water stream emerges. For the past 5 to 6 years, the stream emerged from the glacier through a large tunnel (which he likened to a railroad tunnel). This year, the tunnel is gone (presumably collapsed) and melt water emerges from multiple small portals spread out along the face of the ice terminus. Hall suggested that the water had been warmer in previous years.\r\n   \"In a follow-up report (Jan. 30, 2002), Hall said that later in the summer of 2001, while on one of his almost daily flights over the Snowy Mountain area, he noticed that the hole (vent) was indeed still active [steaming].\"","StartYear":2001,"StartMonth":6,"StartDay":27,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Snowy","ParentVolcano":"Snowy","VolcanoID":"ak257","ParentVolcanoID":"ak257"},{"ID":521,"Name":"Hague, Mt 2001/11","Description":"   McGimsey and others (2004) report that \"NWS observers in Cold Bay contacted AVO on the morning of November 7, 2001 to report a small steam plume originating from the south side of Pavlof; they also received several Pilot Weather Reports (PIREPS) describing the same observation. About a month later, on December 13, 2001, NWS personnel in Cold Bay reported steam issuing from a point about half-way down the south flank of the volcano. The plume rose to a height of about 6,000 ft (~1,830 m) before dissipating. A Pen Air pilot corroborated the report and added that the steaming was coming from a 'hill' on the southwest flank; this pilot added that he encountered a strong sulfur smell on a flight by the volcano that day. AVO detected no unusual seismicity or thermal anomalies. Based on conversations with the Pen Air pilot, AVO determined that the source of steaming was likely the fumarole field on nearby Mt. Hague, a late Pleistocene volcano with no historic activity.\"","StartYear":2001,"StartMonth":11,"StartDay":7,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2001,"EndMonth":12,"EndDay":13,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Hague, Mt","ParentVolcano":"Emmons Lake Volcanic Center","VolcanoID":"ak113","ParentVolcanoID":"ak93"},{"ID":529,"Name":"Hague, Mt 2002/2","Description":"   From Neal and others (2005): \"On February 15, 2002, AVO received a pilot report of steaming from the vicinity of Pavlof Volcano on the Alaska Peninsula.  AVO determined that the pilot had most likely spotted a steam plume from the summit crater of Hague, a youthful volcanic cone about 7 km (4 mi) southwest of Pavlof Volcano on the Alaska Peninsula.  The pilot reported that snow had melted in a crater at the site of this steaming, but the 'activity was not significant.'  AVO had received a similar report in mid-December, 2001 (steam was reported emanating from a 'hill' southwest of Pavlof, rising to about 6,000 ft [1,830 m] and dissipating, accompanied by a strong sulfur smell; McGimsey and others, 2005).  The Pavlof seismic network showed nothing unusual in conjuction with any of the reports, and no anomalies were observed in satellite images.\r\n   \"'Steaming' reports for the vicinity of Hague on the Alaska Peninsual continued into the spring.  In early April, AVO received email from a teacher in King Cove (35 km [20 mi]) south-southwest of Hague) describing 'steam from a large crater offset on the southwest side of Pavlof.'  Based on the position of the reported activity, it appears likely that the source was also a crater at the summit of Hague.  This same observer got a better look from the air on April 18 and confirmed that the crater was still steaming and releasing notable amounts of sulfur-bearing gas.  On May 1, USFWS personnel in Cold Bay shared photographs of steaming from the vicinity of Hague and noted that this was the first such observation in at least three years.\r\n   \"In mid-April, AVO seismologist examined records from the adjacent Pavlof Volcano network and noted that a family of shallow long-period events had been recorded in the general vicinity of Hague (J. Caplan-Auerback, written comm., 2002).  A second swarm of similar events occurred in May.  While the significance of this seismicity remains unclear, its coincidence in time with reports of increased steaming from the Hague crater does suggest a transient increase in heat flux and resulting hydrothermal activity.\"","StartYear":2002,"StartMonth":2,"StartDay":15,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2002,"EndMonth":5,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Hague, Mt","ParentVolcano":"Emmons Lake Volcanic Center","VolcanoID":"ak113","ParentVolcanoID":"ak93"},{"ID":530,"Name":"Shishaldin 2002/5","Description":"   From Neal and others (2005): \"In mid-May 2002, AVO detected an increase in the number of shallow, low-frequency seismic events at Shishaldin.  In addition, a number of 2-3 minute-long tremor-like signals were recorded.  No correlative thermal anomalies or other observations of unusual activity were reported to AVO.  AVO mentioned the activity in its weekly update of May 17.  On May 24, AVO reported in its weekly update that the numbers of locatable low-frequency seismic events had decreased to background levels.  Based upon this observation and the lack of correlative satellite-detected thermal anomalies or ground observer reports of anomalous activity, AVO concluded that the seismicity was probably typical of ongoing phreatic activity in the central crater and did not reflected significant restlessness.  AVO made no further mention of Shishaldin in May or June weekly updates.\r\n   \"On August 16, AVO received notification of a pilot report of possible volcanic activity at Shishaldin via the NWS Alaska Aviation Weather Unit (AAWU).  The pilot report indicated: 'Shishaldin Volcano appears to be erupting.  Steam and dark clouds rising to 10,500 [feet] moving NW-SE'.  During a follow up phone call to the area, AVO learned that a NWS weather observer in Cold Bay, about 100 km (60 miles) east of the volcano, reported a steam plume above Shishaldin.  According to operational protocols, the AAWU issued an eruption SIGMET advising the aviation community of the possibility of airborne volcanic ash.\r\n   \"Upon receiving the pilot report, AVO examined seismic and satellite data and determined that Shishaldin was at a normal background state and had not erupted.  Further discussions with the NWS weather observer in Cold Bay indicated that the observed steam plume was not unlike those commmonly seen at Shishaldin.\"","StartYear":2002,"StartMonth":5,"StartDay":15,"StartTime":null,"StartQualifier":7,"StartQualifierUnit":"Days","EndYear":2002,"EndMonth":8,"EndDay":16,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":60,"Name":"Great Sitkin 2002/5","Description":"   This entry is not an eruption, but is a description of unusual earthquake activity at Great Sitkin that may be associated with volcanic events.\r\n\r\n   From 06/02 (BGVN 27:06) : \"Abnormal tremor and earthquake swarms in May 2002\r\nOn 27 and 28 May the Alaska Volcano Observatory (AVO) detected anomalous seismicity at Great Sitkin, a volcano located 1,895 km SW of Anchorage, Alaska. On 27 May two periods of seismic tremor lasted for 20 and 55 minutes and on 28 May earthquake swarms began at 0306 and 1228. The earthquake swarms each began with a relatively large event (ML 2.2 and ML 4.3) followed by tens to hundreds of smaller aftershocks, most located 5-6 km SE of the crater at depths of 0-5 km. Both the tremor and earthquake swarms represent significant changes from background seismicity at Great Sitkin. However, aftershocks declined significantly overnight, and seismicity returned to background levels with a lack of recorded tremor since 27 May. Satellite imagery showed no signs of surface volcanic activity, and no reports of anomalous activity were received by AVO.\"","StartYear":2002,"StartMonth":5,"StartDay":27,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":2002,"EndMonth":5,"EndDay":28,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":"","Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":1001,"Name":"Korovin 2002/7","Description":"McGimsey and others (2008) figure 42 containes an astronaut image of Korovin from July 5, 2002 showing ash deposits on the upper east flank of Korovin. This deposit was likely the result of a small, phreatic eruption at Korovin some time prior to the satellite image being taken.","StartYear":2002,"StartMonth":7,"StartDay":null,"StartTime":null,"StartQualifier":1,"StartQualifierUnit":"Months","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Korovin","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak171","ParentVolcanoID":"ak17"},{"ID":526,"Name":"Wrangell 2002/8","Description":"   From Neal and others (2005): \"On August 1, 2002, a spectacular, clear day in south-central Alaska, AVO received several calls reporting an eruption of Mount Wrangell. Callers reported a dark cloud drifting downwind from the general summit area and a dark deposit high on the snow-covered flank of the volcano.\r\n   \"AVO seismologists checked data from the Wrangell seismic network and, based on a lack of correlative seismicity, concluded that no eruption or explosion had occurred. AVO also consulted with Wrangell St. Elias National Park Geologist Danny Rosenkrantz, who suggested that high winds had lofted fine-grained material exposed in the area near the summit fumaroles. On August 4, an AVO geologist traveling in the area verifed that a diffuse, light gray stripe extended a short distance down the flank of the volcano, emanating from the western rim of the caldera. \r\n   \"Subsequently, AVO received a video from Copper Center resident Brad Henspeter who witnessed the event on August 1. The tape is just a few minutes long and shows the waning portion of the event at approximately 1:15 pm ADT. In a written accompaniment to the videotape, Henspeter added his own commentary and recollections of the most significant portion of activity. Notable excerpts from his words follow: ‘..ash was dark black . . and billowing . . . multiple billows (puffing) coming one after the next, nearly touching each other. The wind where we were standing was still, however at the top of the mountain the wind was directly from the east . . .the billows were not rising above the top of the mountain.' By the time he and his son returned to a good vantage point to film, about 10-12 minutes later, the billowing had stopped and the 'puffs' had 'turned a more grayish color.' \r\n   \"In the video, there are indeed discrete, light gray 'puffs' that moved downwind and retained their individual.integrity. There are no other weather clouds in the vicinity. A.light gray, relatively motionless and irregular-shaped cloud sits in the vicinity of the caldera rim. There is a good breeze at ground level (indicated by motion in the trees) but at altitude, clouds are not shearing rapidly. High on the snow-covered flank, a gray-colored swath extends from a high point that we identify as the west caldera rim near Mount Wrangell Crater. The end of the video footage shows two distinct dark areas on the rim that is normally snow-covered. Henspeter's son reported a similar but more vigorous event on August 2, 2002 at about the same time of the day, but AVO received no further inquiries or reports. \r\n   \"AVO concluded that no volcanic process of significance was involved and no formal information releases were issued. However, these observations remain enigmatic: lack of any seismicity would seem to preclude a phreatic or magmatic eruption and yet the pulsatory, 'puffing' nature of the dirty clouds is difficult to reconcile with a wind phenomenon.\"","StartYear":2002,"StartMonth":8,"StartDay":1,"StartTime":"13:00:00","StartQualifier":30,"StartQualifierUnit":"Minutes","EndYear":2002,"EndMonth":8,"EndDay":2,"EndTime":"13:00:00","EndQualifier":2,"EndQualifierUnit":"Hours","Volcano":"Wrangell","ParentVolcano":"Wrangell","VolcanoID":"ak326","ParentVolcanoID":"ak326"},{"ID":324,"Name":"Veniaminof 2002/9","Description":"   From Neal and others (2005): \"On the basis of several days of increasingly frequent, emergent seismic events on multiple stations of the new Veniaminof network (Dixon and others, 2002), AVO announced Level of Concern Color Code YELLOW on September 11, 2002.  Following established protocols, the Anchorage Volcanic Ash Advisory Center (VAAC) issued a one-time volcanic ash advisory [see fig. 4 in original text].\r\n   \"Over subsequent weeks, seismicity was characterized by periods of above-background activity alternating with quiet intervals.  Telephone calls to Perryville and other nearby communities[see fig. 5 in original text] turned up no unequivocal observations of unrest until September 24 when AVO received phone reports and digital photographs from the Perryville Native Council.  These images showed small, faint gray clouds rising just above the intracaldera cone that has been the source of all known historical eruptions at Veniaminof (Miller and others, 1998).  One observer described 'puffs' of mixed dark and white clouds approximately every 5 minutes. Another observer described the 'puffs' as solid white and emanating from the top of the cone.\r\n   \"Perryville residents next reported 'plumes of smoke' between 8 and 10 pm on October 1. Others reported 'rumbling' during the evening, however no clearly correlative signals were noted on seismograms.  One and one half minutes of video taken on October 2 or 3, about 2 pm, from the vantage of the Sandy River (~45 km [28 mi] west of the active cone) showed several small, dilute, gray-brown clouds rising about 300-600 ft above the intracaldera cone and drifting a short distance to the north. In the 1.5 minutes of tape, two distinct 'puffs', about 1 minute apart, rise from the cone and drift downwind.  The cone was not unusually snow free, however, a dark covering of ash was visible on the caldera ice field at the base of the cone and extending generally north.  On October 6, Sandy River Lodge [see fig. 5 in original text] reported black ash and 'smoke' rising 400-500 ft above the cone, explosions, and ground shaking.  \r\n   \"Cloud-free satellite images of the Veniaminof caldera revealed nothing unusual until October 2 when AVO acquired a Moderate Resolution Imaging Spectroradiometer (MODIS) image that captured a localized, gray deposit on the caldera ice field [see fig. 6 in original text].  The image shows a faint, fan-shaped deposit extending generally east from the cone to the caldera boundary and perhaps just beyond.  When viewed in light of reports from Perryville and the video from Sandy River, the dark fan likely represents ash fall from low-level phreatic activity on October 1.  No thermal anomalies were detected in satellite imagery throughout this period and no incandescence was reported.  A compilation of reports from residents and other observers through the end of the year is presented in table 3.  Seismicity and reports of discolored clouds over the intracaldera cone gradually declined through the fall.\r\n   \"A re-invigorated hydrothermal system beneath the intracaldera cone may account for these intermittent ejections of diffuse, ash-bearing clouds. It seems unlikely that this was prompted by a new magmatic intrusion at depth based on the lack of volcano-tectonic earthquakes. Increased hydrothermal activity may have been related to what was, according to some long time residents of the area, one of the rainiest autumns in memory. Although precipitation falling at the elevation  of the intracaldera cone would have been in the form of snow (C. Searcy, NOAA, oral.commun., 2003), precipitation in Cold Bay [see fig. 1 in original text] was approximately 80% above normal for the month of October, according to long term climate records maintained by NWS (National Oceanic and Atmospheric Administration: http://www.arh.noaa.gov/climate.php). King.Salmon, the other nearby long-term weather station, recorded approximately 45% and 60% more precipitation than normal in the months of September and October, respectively.\"\r\n   The 2002 activity continued into 2003.  From McGimsey and others (2005): \"On January 3, 2003, AVO belatedly received a report from the caretaker of a lodge located northwest of the volcano describing his observations from about mid-December, 2002, during clear weather, of distinct puffs of steam coming from the intracaldera cone. AVO upgraded the Level of Concern Color Code to YELLOW on Monday, January 6, 2003. Several weeks of poor weather conditions followed before clear views revealed that intermittent episodes of steam and diffuse ash emissions from the active cone continued [see fig. 15 in original text]. AVO seismologists detected the onset of small, volcano-tectonic earthquakes on Veniaminof seismic stations beginning on the morning of January 29, 2003 and a commensurate decline in amplitudes and numbers of low-frequency events (S. Moran, written communication). Elevated seismicity continued, and on March 11, a 4-hour period of continuous seismic tremor was observed followed by 17 hours of discrete seismic events and 3-4-minute-long tremor bursts. This culminated with another 4-hour period of continuous tremor on March 12, which was followed by a distinct decline in seismicity over the next several days. The last report of emissions from the active cone was from Mark Battaion in Perryville on March 23, 2003 [see fig. 16 in original text].\r\n   From Neal and others (2005): \"In the summer of 2003, AVO geologists visited the summit caldera of Veniaminof and examined the intracaldera cone for evidence of the 2002 activity (K. Wallace, written.commun., 2003).  Within 50 m (160 ft) of the east side of the cone, the ice surface was dusted with fine wind blown debris derived from the cone. A crevasse at the base of the cone revealed a prominent, 1-cm-thick (0.4 in), black, scoriaceous deposit 1 m (3 ft) beneath the surface [see fig. 7a, b, in original text]. Scoria fragments ranged from fine ash to medium lapilli (with a maximum diameter of 5 mm [0.2 in]). The base of the crevasse was not visible, however no other debris layers were recognized over a thickness of at least 10 m (33 ft) suggesting that this type of depositional event was not common (e.g. wind reworking of cone debris).  In hand sample, the tephra consists of abundant black iridescent, glassy scoria; hydrothermally altered scoria (with native sulfur and secondary minerals); and rare individual crystals.  Microscopic investigation showed all glass fragments to be devitrified.  Wallace and co-workers concluded that this deposit represented recycled cone material ejected during low-level phreatic explosions in October 2002.\r\n   \"In response to the 2002 unrest at Veniaminof, AVO staff conducted outreach to communities in the vicinity of the volcano and compiled contact phone lists of observers and others who would be helpful in tracking activity on our behalf.  We were in frequent telephone contact with people in Perryville, regional airlines, and our colleagues at U.S. Fish and Wildlife Service (USFWS) and the Alaska State Troopers who were often flying in the area.  At least one private lodge near the volcano contacted AVO for information on potential hazards.  AVO posted a 'Frequently-Asked-Questions' about Veniaminof on our web site, a first in the history of AVO.\r\n   \"Interestingly, the change in Level of Concern Color Code to YELLOW for Veniaminof occurred on September 11, 2002, during a time when the Department of Homeland Security had recently established a Threat Level of ORANGE.  It is therefore possible that reaction to our initial information release on September 11 may have been more pronounced than usual, and confusion over the two color designations may explain why some residents of the Peninsula thought AVO had declared an 'imminent' eruption.\r\n   \"From September 11 to November 18, 2002, AVO issued three special information release notices on the increased seismicity and its eventual decline at Veniaminof.  The volcano was mentioned in weekly updates from September 13 through November 22.  AVO reverted to color code GREEN on November 18.  During the time of heightened activity, the AVO seismology and remote sensing groups increased the frequency of analysis of Veniaminof seismicity and relevant satellite imagery.\"","StartYear":2002,"StartMonth":9,"StartDay":28,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":2003,"EndMonth":3,"EndDay":23,"EndTime":null,"EndQualifier":1,"EndQualifierUnit":"Months","Volcano":"Veniaminof","ParentVolcano":"Veniaminof","VolcanoID":"ak301","ParentVolcanoID":"ak301"},{"ID":527,"Name":"Martin 2002/12","Description":"   From Neal and others (2005): \"On December 11, 2002, the National Weather Service office in King Salmon reported a 'large steam plume' emanating from mountains east of King Salmon and extending up into the cloud deck. No discoloration was noted in the cloud. AVO staff examined the real-time seismic  data from the Katmai area network and saw no evidence of anomalous behavior. No cloud or thermal anomaly was detected in Advanced Very High Resolution Radiometer (AVHRR) images. This information was relayed back to NWS in King Salmon. \r\n   \"About 45 minutes later, the NWS at the Anchorage Air Route Traffic Control Center issued an urgent pirep (UUA) based on a pilot report of a 'strange plume' from Martin or Mageik that extended into cloud deck at about 7,000-10,000 ft. AVO concluded that this was the same observation reported earlier from King Salmon and took no further action.\"","StartYear":2002,"StartMonth":12,"StartDay":11,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Martin","ParentVolcano":"Martin","VolcanoID":"ak189","ParentVolcanoID":"ak189"},{"ID":528,"Name":"Mageik 2002/12","Description":"   From Neal and others (2005): \"On December 11, 2002, the National Weather Service office in King Salmon reported a 'large steam plume' emanating from mountains east of King Salmon and extending up into the cloud deck. No discoloration was noted in the cloud. AVO staff examined the real-time seismic  data from the Katmai area network and saw no evidence of anomalous behavior. No cloud or thermal anomaly was detected in Advanced Very High Resolution Radiometer (AVHRR) images. This information was relayed back to NWS in King Salmon. \r\n   \"About 45 minutes later, the NWS at the Anchorage Air Route Traffic Control Center issued an urgent pirep (UUA) based on a pilot report of a ‘strange plume' from Martin or Mageik that extended into cloud deck at about 7,000-10,000 ft. AVO concluded that this was the same observation reported earlier from King Salmon and took no further action. \r\n   \"Mageik and Martin are adjacent, mostly ice-covered stratovolcanoes within Katmai National Park and Preserve on the Alaska Peninsula. Other than fumarolic activity from summit craters, there are no credible reports of historical eruptive activity at either volcano (Fierstein and Hildreth, 2000). Steam from the 500-meter-wide (1,640 ft) summit crater of Martin is vigorous and nearly continuous, with plumes occasionally rising 600 m (2,000 ft) or more above the vent and extending downwind for up to 20 km (12 mi). Steam plumes rising from the summit crater of Mageik are also common. This activity at both volcanoes results in frequent telephone calls to AVO.\"","StartYear":2002,"StartMonth":12,"StartDay":11,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mageik","ParentVolcano":"Mageik","VolcanoID":"ak187","ParentVolcanoID":"ak187"},{"ID":544,"Name":"Shishaldin 2003","Description":"   From McGimsey and others (2005): \"The AAWU [Alaska Aviation Weather Unit] called AVO on January 31, 2003 to relay an 11:00 AST (2000 UTC) PIREP from the Cold Bay Flight Service Station of a steam plume from Shishaldin with tops to 16,000 ft (4,875 m) ASL and moving to the north. The pilot reported no sulfur smell. AVO staff checked the seismic data for Shishaldin and found no change at the time of the PIREP. Another PIREP was reported to AVO on the morning of September 12, 2003 concerning a steam plume observed rising 500 ft (~150 m) above the top of Shishaldin. The time of the report was 11:07 ADT (19:07 UTC) and neither satellite nor seismic data indicated anything unusual. This information was subsequently reported back to AAWU.\"","StartYear":2003,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":541,"Name":"Mageik 2003/2","Description":"   From McGimsey and others (2005): \"AVO received a PIREP of steaming in the Katmai area -- specifically at coordinates 58\u0026deg;16', 154\u0026deg;50' -- that was rising to an estimated 17,000 ft. ASL on February 15, 2003. The AAWU called to consult as to whether or not to issue a Significant Meteorological Information Statement (SIGMET). A check of the webicorders and spectrograms revealed no unusual seismicity at any of the Katmai Group volcanoes and no advisory was forthcoming. Based on the coordinates reported and the past reports of steaming, the most likely source was Mageik [see fig. 9 in original text]. Nearby Martin also typically issues a vigorous steam plume.\r\n   \"An observer in the town of Naknek (about 110 km [70 mi.] from Mageik) called on April 8, 2003 to report two 'significant' steam plumes coming from 2 mountains in the VTTS the previous evening. Having lived in the area for 40 years, he stated that he had never seen anything as large as these plumes, although he estimated the plumes to be about 3,000 ft above the mountaintops.  AVO staff checked the webicorders and spectrograms of the greater Katmai network and found nothing out of the ordinary. The observer was advised that he was likely seeing vigorous steam plumes emanating from Martin and Mageik, a common occurrence in the Katmai area.\"","StartYear":2003,"StartMonth":2,"StartDay":15,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2003,"EndMonth":4,"EndDay":8,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mageik","ParentVolcano":"Mageik","VolcanoID":"ak187","ParentVolcanoID":"ak187"},{"ID":542,"Name":"Pavlof 2003/3","Description":"   From McGimsey and others (2005): \"A barge operator reported seeing Pavlof volcano erupting about 10 AM AST on March 16, 2003. A check of spectrograms revealed no activity. CWSU staff was informed of the report; they had already reviewed the latest satellite imagery and saw no ash signature (the area was cloudy with a ceiling of around 3,000 ft.). AVO remote sensing specialists corroborated that there was no indication of activity. Strong fumaroles on the flank, and in the crater, of nearby Mt. Hague vent of Emmons Lake Caldera occasionally produce steam clouds that from certain vantage points appear to originate at Pavlof. A similar occurrence [at Hague] was documented in 2001 (McGimsey and others, 2005) and in 2002 (Neal and others, 2005).\"","StartYear":2003,"StartMonth":3,"StartDay":16,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":537,"Name":"Wrangell 2003/6","Description":"   From McGimsey and others (2005): \"Danny Rosenkrans, geologist for the Wrangell-St. Elias National Park and Preserve, contacted AVO on June 13, 2003 with photographs taken by a local resident on June 11, 2003 showing an unusual, towering, cloud over the summit area of Mt. Wrangell (fig. 4). Although the cloud might simply have been a common cumulus cloud fortuitously located at or near the summit, the lack of other cumulus clouds in the area over nearby Mts. Drum and Sanford suggest that instead, calm weather conditions permitted steam emissions from the known summit fumaroles to coalesce and form the plume-like cloud over Wrangell. AVO receives several reports per year from pilots and local residents who observe what they consider to be larger than normal steam clouds situated over the summit.\"\r\n   \"On September 18, 2003 the Center Weather Service Unit (CWSU) called at 12:50 pm ADT with a Pilot Weather Report (PIREP) of a '2,000-to 2,300-foot-high steam plume' over Mt. Wrangell. The pilot reported no ash or sulfur smell. AVO scientists checked satellite imagery and seismograms and found nothing unusual.\"","StartYear":2003,"StartMonth":6,"StartDay":11,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2003,"EndMonth":9,"EndDay":18,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Wrangell","ParentVolcano":"Wrangell","VolcanoID":"ak326","ParentVolcanoID":"ak326"},{"ID":543,"Name":"Hague, Mt 2003/7","Description":"   From McGimsey and others (2005): \"On July 7, 2003, AVO scientists conducting seismic network maintenance near Mt. Hague on the rim of Emmons Lake Caldera noticed that the crater lake typically present was almost completely gone and all that remained was a few isolated pools surrounded by several vigorously venting fumaroles, and yellow sulfur deposits in the center of the crater. Mud cracks suggested that the lake had drained or evaporated rather recently. A photograph taken a week later, August 16, 2003, shows a full lake. Photographs taken of the crater lake on August 16, 2002 also show the lake filled with water.\r\n   \"The Hague crater lake apparently has a history of draining and refilling. Sporadic checks of the crater since 1973 have found it empty about as often as full (T. Miller, written communication, 2003). The most recent observations [2003] verify that the lake is capable of reforming within days or weeks.\"","StartYear":2003,"StartMonth":7,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Hague, Mt","ParentVolcano":"Emmons Lake Volcanic Center","VolcanoID":"ak113","ParentVolcanoID":"ak93"},{"ID":539,"Name":"Iliamna 2003/7","Description":"   From McGimsey and others (2005): \"On July 25, 2003, an avalanche of snow, ice, and rock occurred at Iliamna volcano, a site of frequent spring and summer avalanches (Neal and others, 1995; McGimsey and Wallace, 1999; McGimsey and others, 2004). The event lasted 4 minutes and was recorded on seismometers located as far away as 75 km (46 mi) on Augustine volcano. The avalanche presumably initiated from the same vicinity as in previous years, a steep portion of the east-southeast flank adjacent to an extensive fumarolic field and large zone of altered rock [see fig. 7 in original text].\"","StartYear":2003,"StartMonth":7,"StartDay":25,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":587,"Name":"Augustine 2003/9","Description":"   From McGimsey and others (2005): \"AVO received a pilot report through Kenai Flight Service of increased steaming at Augustine\r\nvolcano about mid-day on September 9, 2003. Concomitant to this report we received an inquiry about Augustine from the Homer Police Department. A check of the seismograms and spectrograms revealed nothing unusual.\"","StartYear":2003,"StartMonth":9,"StartDay":9,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":502,"Name":"Katmai 2003/9","Description":"   From McGimsey and others (2005): \"On September 21, 2003, strong northwesterly winds sweeping through the VTTS in Katmai National Park entrained ash from the 1912 deposits to form a substantial cloud that was carried over Shelikof Strait, Kodiak Island, and the Gulf of Alaska. Particle fallout on Kodiak Island was mistaken as material from an eruption cloud. Upon receiving the reports from Kodiak, AVO scientists analyzed satellite imagery and area seismic data and determined that the phenomenon was non-eruptive in origin. The National Weather Service (NWS) was contacted to confirm the existence of strong winds in the area, and then AVO issued an Information Release at 2:30 pm ADT (22:30 UTC) explaining the cloud's source and cautioning that despite the non-eruptive origin, the cloud -- composed of remobilized volcanic ash -- nonetheless posed a potential hazard to aircraft.\"","StartYear":2003,"StartMonth":9,"StartDay":21,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Katmai","ParentVolcano":"Katmai","VolcanoID":"ak147","ParentVolcanoID":"ak147"},{"ID":545,"Name":"Akutan 2003/10","Description":"   From McGimsey and others (2005): \"AVO received reports on October 15, 2003 from several sources - both on land and at sea - of increased steaming from the northeast flank of the volcano. All reports indicate that the steaming was located at about the 1,500 to 2,000 ft. elevation (~500 to 600 m), and not from the summit crater or cone. A review of seismic data indicated nothing unusual. Hot Springs Bay Valley, which contains a string of thermal springs, heads on the northeast flank of Akutan, and a well-documented and long-lived fumarolic field exists at about the 1,500 ft. level (Richter and others, 1998) [see figs. 20 and 21 in original text]. Under favorable meteorological and visibility conditions, steam coalescing from this field can produce persistent steam clouds. AVO staff further reviewed recent seismic data and queried local residents in Akutan village. Nothing unusual was found and no further reports came forth.\"","StartYear":2003,"StartMonth":10,"StartDay":15,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":538,"Name":"Redoubt 2003/11","Description":"   From McGimsey and others (2005): \"On November 25, 2003, an employee on the 18th floor of the Conoco Phillips Building in downtown Anchorage reported a 'white plume' over the general vicinity of Redoubt. Seismograms and spectrograms revealed nothing unusual other than typical wind noise. AVO staff called the CWSU of the FAA to request a PIREP from any planes flying over Redoubt and a short while later learned that there was 'no steam but plenty of blowing snow'. Photographs sent to AVO from the original observer at Conoco Phillips show an abrupt cloud edge forming over the general Redoubt area, and billowing downwind to the southeast. The clouds were a weather phenomenon that was mistaken for possible unrest at the volcano. AVO frequently receives similar reports about the Cook Inlet volcanoes during the spring and fall.\"","StartYear":2003,"StartMonth":11,"StartDay":25,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Redoubt","ParentVolcano":"Redoubt","VolcanoID":"ak231","ParentVolcanoID":"ak231"},{"ID":548,"Name":"Martin 2004","Description":"   From Neal and others (2005; Open File 2005-1308): \"On February 17, AVO received a call from the Bristol Bay Fire Chief Alan Williams who reported a 'steam column, all white, rising vertically above mountains to the east (of Naknek, 25 km [16 mi] west of King Salmon) * * * bigger than normal, and dissipating with altitude.' Williams had been a resident of the area for some years and felt this was a much larger a steam plume than was typical for the Katmai group. Williams' photos [see fig. 12 in original text] show the plume rising from Mount Martin, one of the Katmai Group of volcanoes with a very active and robust fumarolic area near its summit. AVO checked the seismic records for the Katmai area and noted no unusual signals for several hours before or after the time of this sighting.\r\n   \"On October 7, AVO received a pilot report from NWS describing 'a volcano spewing steam and ash' approximately in the location of Martin or Mageik; seismicity was normal and this information was relayed back to NWS who took no further action.\"","StartYear":2004,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Martin","ParentVolcano":"Martin","VolcanoID":"ak189","ParentVolcanoID":"ak189"},{"ID":549,"Name":"Westdahl 2004/1","Description":"   From Neal and others (2005): \"On January 7, 2004, 90 earthquakes occurred over a period of 12 hours beneath Westdahl Volcano on Unimak Island in the eastern Aleutians.  Since the short-period seismic network was installed on this volcano in 1998, the majority of background seismicity has occurred in the vicinity of Faris Peak, a young, intracaldera cone 4 km (2.5 mi) east-northeast of Westdahl Peak (fig. 21B.) The 2004 swarm consisted of earthquakes ranging in size from ML (local or Richter magnitude) = 0.2 to ML = 1.6. The largest earthquakes (ML = 1.6) occurred during the second half of the swarm. Depths ranged from sea level to 8 km (5 mi) below sea level. Over the next 10 months, AVO detected several deep, long-period events below the volcano. Given the location of this swarm beneath the general area of the most recent historical eruptions and the subsequent swarm of deep, long-period earthquakes, this seismicity most likely represents a magmatic intrusion. Due to the short duration and abrupt termination of this swarm, AVO did not raise the level of concern color code for Westdahl, nor did AVO mention the activity in its weekly updates.\"","StartYear":2004,"StartMonth":1,"StartDay":7,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Westdahl","ParentVolcano":"Westdahl","VolcanoID":"ak322","ParentVolcanoID":"ak322"},{"ID":531,"Name":"Shishaldin 2004/2","Description":"   From Neal and others (2005): \"Since its last eruption in 1999, the background level of seismic activity at this frequently active volcano has remained relatively high and consists of many small, discrete, volcano-tectonic earthquakes, small explosion signals, and short (2-6 min) periods of tremor-like signals. Typically, this activity is interpreted to reflect either hydrothermal or magmatic processes occurring high in the conduit and deep in the summit crater of Shishaldin (Caplan-Auerbach and Petersen, 2005). Reports of ash emission or other eruptive phenomena that may have been related to this seismicity were few. However, on February 17, a Peninsula Airlines pilot noted a hazy ash layer above Shishaldin (R. Hazen, written commun., 2004). On February 20, a pilot report reached AVO describing an ash cloud to 16,000-18,000 ft ASL (4.8-5.5 km) above Shishaldin [note: AVO also received an incorrect pilot observation of ash from Mt. Dutton on February 20; this was later corrected to be Shishaldin.]. AVO seismologists identified no correlative seismicity or anything unusual on associated satellite images. NWS issued a one-time SIGMET based on the pilot report per operational protocols. A similar report from a long-time Cold Bay resident arrived via email on February 26 stating that Shishaldin was emitting steam and ash to 2,000-3,000 ft (600-900 m) above the summit; seismic and satellite data indicated no eruptive activity.\r\n   \"In late April and early May of 2004, seismicity at Shishaldin intensified and volcanic tremor similar to that observed during the eruption in 1999 reappeared. A thermal anomaly over the summit was noted on May 3 in MODIS imagery. Airwaves detected by acoustic pressure sensors suggested a shallowing of the source of this tremor over time (Petersen and others, 2004). In response, AVO raised the Level of Concern Color Code to YELLOW on May 3. On May 16, a pilot reported an ash plume rising 1,000 feet above the summit. Satellite data showed a vigorous steam plume possibly containing a minor amount of ash. Volcanic tremor and small explosions recorded on a pressure sensor continued into the summer and satellite images continued to record an intermittent, weak thermal anomaly into mid-August (S. Smith, written commun., 2005). On July 24, an AVO field crew approached the volcano by helicopter and observed vigorous steaming from the summit crater and recent (?) ash on the upper slopes of the volcano [See figures 18-20 in original text].\r\n   \"Low-level volcanic tremor continued at Shishaldin with little variation from late summer through the end of the year. AVO received at least two additional pilot reports of 'smoke' and 'steam' from Shishaldin, both on September 24. After more than five months at Color Code YELLOW, AVO downgraded Shishaldin to GREEN on October 26 based on the lack of any confirmed ash emission or other eruptive activity. Unlike most other Alaskan volcanoes, Shishaldin appears to have a high level of background seismicity, at least during the period following an eruption sequence (Caplan-Auerbach and Petersen, 2005; Nye and others 2002).\"","StartYear":2004,"StartMonth":2,"StartDay":17,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2004,"EndMonth":5,"EndDay":17,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":325,"Name":"Veniaminof 2004/2","Description":"   From Neal and others (2005): \"In mid-February, residents of Perryville, located 35 km (22 mi) south of Veniaminof, reported small ash clouds rising several hundred feet above the intracaldera cinder cone of the volcano. At other times, vigorous, ash-free steam plumes were reported. On February 19, AVO received a pilot report of a small black ash cloud rising approximately 300 ft (90 m) above the cone and fresh ash on the snowfield east of the cone [see fig. 13 in original text]. A satellite image from the same day showed a dark deposit within the Veniaminof summit caldera. Seismic activity coincident with these reports was insignificant and AVO considered these small explosions to be typical of background activity at Veniaminof where ground water within the active cone occasionally flashes to steam producing a small explosion. The volcano had last produced such activity over a several month-period in late 2002 and early 2003 (Neal and others, 2005; McGimsey and others, 2005). On February 23, AVO described this activity in a special Information Release but remained at Level of Concern Color Code GREEN. AVO received no reports of activity over the next two weeks. Satellite imagery did not indicate increased surface temperatures or further ash deposits and seismicity remained low. AVO ceased special mention of Veniaminof in its weekly updates on March 5.\r\n   \"In mid-April, seismicity beneath Veniaminof began to increase and several episodes of volcanic tremor and isolated volcano-tectonic earthquakes were recorded. Tremor pulses were several minutes in duration and the largest were recorded on most stations in the network. On April 19, residents of Perryville reported a steam emission from the intracaldera cone that had occurred on April 18, possibly containing a small amount of ash. This burst rose an estimated 2,000 ft (610 m) above the intracaldera cone. Based on this renewed activity and elevated seismicity,  AVO elevated the Level of Concern Color Code for Mount Veniaminof to YELLOW. NWS issued a VAA and the FAA issued a temporary flight restriction from the surface to 14,000 ft ASL (4,270 m) within a 10 nautical mile (18.5 km) radius of the center of the volcano.\r\n   \"Over the next few weeks, Perryville residents reported vigorous steam plumes (often described as mushroom-shaped clouds) over the intracaldera cone. AVO received few reports of small ash emissions until April 25 when, using a newly installed remote video camera, as many as 25 small steam and ash emissions were observed over an 8-hour period, most rising about 2,000 ft (610 m) above the active cone [see fig. 14 in original text].\r\n   \"Through the remainder of spring and into summer, passing pilots, Perryville residents, personnel at Wildman Lake Lodge, and the AVO internet camera continued to record occasional steam plumes and steam and ash bursts, at times reaching as much as 915 m (3,000 ft) above the intracaldera cone and drifting as far as 16-32 km (10-20 mi). Poor weather obscured views of the volcano on many days, however bursts of tremor recorded on the seismic network likely reflected the continuation of small ash emissions, or 'puffs'. On May 5, a pilot spotted ash to 610 m (2,000 ft) above the cone and drifting east-southeast; on May 18, a pilot reported ash up to 3,000 ft (915 m) above the cone and drifting 32 km (20 mi) downwind. On May 26, satellite images of the volcano showed ash deposits on the north and southeast caldera floor.\r\n   \"Aerial views on June 27 revealed that much of the caldera floor was covered by a thin, dark layer of ash. On July 10, an AVO crew flying inside the caldera on a clear, calm day witnessed one of these ash bursts and captured it on video. As the helicopter approached the cone, only a faint wisp of steam and volcanic gas emerged from the summit of the intracaldera cone that consists of a series of coalescing craters each several 10s to 100 m wide. Suddenly, two closely spaced (20-30 seconds apart) vigorous explosions of gray-tan ash emerged from one of the central craters. The discrete puffs were followed by at least 2.5 minutes of continuous roiling of ash from the crater. Ash rose several hundred m (700-1,000 ft) above the cone and drifted downwind; ballistics and incandescence are not visible in this video clip. On July 22, an AVO field crew within the Veniaminof caldera witnessed another typical ash burst rising a few hundred ms (less than 1,000 ft) above the summit of the cone (fig. 15). Fallout was largely confined to the area around the base of the cone.\r\n   \"AVO geologists visited the ice field by helicopter in late July and reported a discontinuous, 1- to 2-mm thick ash blanket. They observed no large bombs or ballistics beyond the base of the cone, suggesting that recent ash emissions had not been accompanied by energetic explosions of large rock fragments. Further, they reported no changes in the ice field that would indicate subglacial melting. Additional observations of the cone were made in early August and photographs capture ash-poor puffs rising from one of several summit craters on the cone [see figs. 16, 17 in original text]. On August 7, geologists recorded 6-10 puffs over the course of about 10 minutes of focused observation. They reached about 150 m (500 ft) above the summit of the cone in fairly calm wind conditions.\r\n   \"Steam and ash emissions and correlative tremor bursts continued sporadically through the summer of 2004 but with decreasing frequency and intensity. Cloudy weather precluded any visual observations for much of September and October, however seismic signals continued to record small tremor bursts similar to those correlated with confirmed ash emissions earlier in the year. At times, only weak steaming was visible above the intracaldera cone. The last ash emission with localized ash fall was noted on the web camera images in early September. The pilot of a small aircraft reported 'light to moderate smoke' from Veniaminof on September 13. On October 26, AVO lowered the level of concern color code to GREEN based on a decline in the level of activity and an accompanying decrease in seismicity.\r\n   \"In response to the 2004 unrest at Veniaminof, AVO staff conducted outreach to communities in the vicinity of the volcano and revised existing contact phone lists of observers and others in the area. To track and document activity, a web-camera system was installed in Perryville in April (with assistance from the Perryville School and Perryville Village Council, gratefully acknowledged.) These images along with other graphical and text information were made available to the public via the AVO web site. AVO issued seven special Information Releases on the activity at Veniaminof.\"","StartYear":2004,"StartMonth":2,"StartDay":19,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"","EndYear":2004,"EndMonth":9,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Veniaminof","ParentVolcano":"Veniaminof","VolcanoID":"ak301","ParentVolcanoID":"ak301"},{"ID":1011,"Name":"Korovin 2004/6","Description":"McGimsey and others (2008) and Neal and others (2009) detail satellite imagery and field observations of ash on the upper east flank of Korovin volcano in late June - early July, 2004, likely from a small phreatic eruption of Korovin prior to late June.","StartYear":2004,"StartMonth":6,"StartDay":null,"StartTime":null,"StartQualifier":1,"StartQualifierUnit":"Months","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Korovin","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak171","ParentVolcanoID":"ak17"},{"ID":546,"Name":"Spurr 2004/7","Description":"   For a complete report of the unrest at Spurr between 2004 and 2006, please see Coombs and others (2006), available online at \u003ca target=\"_blank\" href =\"http://pubs.usgs.gov/pp/pp1732/pp1732b/index.html\" \u003e http://pubs.usgs.gov/pp/pp1732/pp1732b/index.html\u003c/a\u003e.\r\n   From Neal and others (2005): \"In early July 2004, AVO seismologists noted an increase in volcano-tectonic and long-period earthquake activity beneath the summit of Mount Spurr Volcano (Power, 2004; Power and others, 2004). About the same time, AVO was contacted by a long-time Alaskan pilot who flew near the volcano on July 11 and saw a small steam plume from the approximate 5,500 foot level of the east side of Crater Peak. She also reported an unusual sulfur dioxide odor. Based on this pilot report and the increase in seismicity, AVO launched a fixed-wing observation flight on July 15. Clouds prevented a view of the summit of Spurr, but Crater Peak and the lower south and east flanks of the Spurr summit dome were clear. Crater Peak appeared unchanged from previous views following the 1992 eruption and nothing unusual was noted along any of the glacier margins or termini around Crater Peak. The east flank of the Spurr summit dome, however, was marked by as many as a dozen dark debris flow lobes that emanated primarily from point-sources within the glacial cover [see fig. 5 in original text] (McGimsey and others, 2004).\r\n   \"Increased daily counts of shallow (5-10 km or 3-6 mi below sea level) earthquake activity combined with observations of debris flows from the summit prompted concern about the possibility of volcanic unrest at Spurr. On Monday July 26, AVO elevated the Level of Concern Color Code to YELLOW. A second AVO overflight on August 2 revealed a circular depression in the Spurr summit ice cap, approximately 50-60 m (165-200 ft) in diameter and 25 m (82 ft) deep [see figs. 6A and B in original text]. The pit contained an ice-encrusted pond with small areas of open water that were distinctly blue-gray in color [see fig. 6C in original text]. This feature became known as the 'ice-cauldron' following usage of the term at ice-covered Icelandic volcanoes.\r\n   \"From early August though early December, the summit ice-cauldron gradually enlarged as blocks of ice ringing the depression sagged and then collapsed into the pit [see figs. 6A, B in original text]. Careful measurements from images taken on August 10 and October 30 indicate that the pit enlarged from about 65 x 95 m (210 x 310 ft) across to 130 x 130 m (430 ft x 430 ft) across in two months' time (M. Coombs, written commun., 2004). Overflights throughout the late summer and fall documented the changing size of the feature, continuing deformation and collapse of surrounding ice walls, and the variability of open water on the surface of the lake. The lake remained a dark battleship gray color, and circular ice-free zones perhaps 5-10 m (16 x 33 ft) across occurred near bedrock lake shoreline and at several points further from the shore [see fig. 6C in original text]. By early December, the areas of exposed bedrock near the bottom of the cauldron had grown and were occasionally observed steaming. Yellow-tinted snow, ice, and rock outcrops in the vicinity of the lake reflected sulfur deposition near the lake margin.\r\n   \"AVO staff conducted several airborne Forward Looking Infrared Radiometer (FLIR) measurements using both a hand held and helicopter-mounted camera and video system. FLIR data confirmed the presence of at least two prominent areas of warm bedrock -- with temperatures as high as ~39o C or 102o F -- on the margins of the lake [see fig. 7A in original text] and on the outer flanks of the summit dome. Lake surface temperatures as measured by FLIR ranged from -10o to 0o C (14o to 32o F) for areas of floating ice and snow debris as well as open water [see fig. 7B in original text].\r\n   \"AVO also gathered an extensive library of satellite imagery of the Spurr edifice and increased satellite analysis frequency using the standard AVO monitoring imagery (Geostationary Operational Environmental Satellites [GOES], Advanced Very High Resolution Radiometer [AVHRR]) and higher resolution imagery (Advanced Spaceborne Thermal Emission and Reflection Radiometer [ASTER], Moderate Resolution Imaging Spectroradiometer [MODIS]). ASTER imagery showed the first signs of a summit thermal anomaly in nighttime thermal infrared data on August 17, 2004; as the summit lake grew in size, the intensity of the ASTER thermal infrared anomaly increased (R. Wessels, oral commun., 2005).\r\n   \"Five fixed-wing gas measurement flights of the Mount Spurr plume were conducted between early August and the end of October. Emission-rate measurements of SO2, H2S, and CO2 gas were made during each of these flights following protocols developed by the USGS (Gerlach and others, 1997; Gerlach and others, 1999; McGee and others, 2001 -- see original paper for complete references). Preliminary results show that CO2 degassing from the summit of Mount Spurr increased from 600 tonnes/day (t/d) in August to 1,300 t/d in September and finally to 1,400 t/d in October. At Crater Peak, CO2 emission rates were 160 t/d, 1,000 t/d and 120 t/d for the same measurement periods. Very small amounts of H2S (=3 t/d) were consistently measured on all of the flights at both degassing locations while no SO2 was detected at all.\r\n   \"Crater Peak has consistently degassed a small amount of CO2 since 1994 that, except for an anomalously higher value in 1997, is typically \u003c200 t/d (Doukas, 1995; M. Doukas, pers. commun., 2004). Carbon dioxide degassing from the summit of Mount Spurr had previously not been detected, although airborne measurements directed specifically at the summit have been rare. The absence of SO2 throughout this period is likely caused by the extremely wet environment at this glacier-clad volcano, where abundant groundwater dissolves SO2 (Doukas and Gerlach, 1995). This scrubbing process would also be greatly enhanced by the presence of the lake at the summit, and the distinctive battleship gray color of this lake might be partly due to dissolved sulfur compounds. The low but positive values for H2S can reflect the release of H2S from a boiling hydrothermal system (Symonds and others, 2001 -- see original text for full citation). This is consistent with historical reports of pressurized fumaroles described by climbers in the summit region and the presence of diffuse boiling-point fumaroles on outcrops of bedrock on the east side of the Mount Spurr summit dome (Turner and Wescott, 1986; C.J. Nye written commun., 2004).\r\n   \"Seismicity at Mount Spurr remained consistently above the pre-July 2004 background level for the remainder of the year, although daily rates of seismicity varied considerably from several to several tens of volcano-tectonic (VT) events per day. The largest tally of identifiable earthquakes in one day was 80 on October 26. Particularly energetic swarms of VT earthquakes located within 20 km (12 mi) of Mount Spurr occurred on October 26 (6.6 earthquakes per hour), November 4 (5.8 earthquakes per hour), August 14 (2.6 earthquakes per hour), and August 21 (1.8 earthquakes per hour). Throughout the unrest in 2004, VT seismicity was concentrated within 5 km (3 mi) of the Mount Spurr summit, in stark contrast to the pre-1992 seismicity (Power, 2004; Power and others, 2004). Located long-period (LP) events occurred at an average depth of approximately 7 km (4 mi) and at variable rates, peaking in November. Deep earthquakes (\u003e 20 km or 12 mi) were located beneath and south of Crater Peak in the same area as the deep seismicity associated with the end of the 1992 eruption of Crater Peak.\r\n   \"Although no eruptive activity ensued in 2004, AVO did experience an eruption response drill. A pilot report of possible ash from Mount Spurr on August 12, followed by a public ash fall advisory issued by the NWS, prompted a daylong flurry of calls, inquiries, and media attention. AVO issued a special Information Release stating that no eruption had occurred. This event— certainly not the first or last of its kind in AVO history—underscored the level of public concern regarding the situation at Mount Spurr and likely reflected a fresh memory of ash fall in 1992. The drill also facilitated review and improvement of communication protocols between AVO and its partner in ash warnings, the National Weather Service.\r\n   \"How unusual is this drastic change in the summit morphology at Mount Spurr? To our knowledge, this is the first documented episode of significant geothermal heating and generation of a substantial lake at the summit, as well as the first known occurrence of watery debris flows from the summit. Historical reports and aerial photographs from the 1950s, 60's and 70's, however, document significant variability in the snow and ice cover at the Mount Spurr summit. During periods of lower-snow levels, a crater-like structure becomes visible. This feature was described in March and others (1997) as a ~200 to 300 m (650-1,000 ft) diameter feature open to the east-northeast. In this same 1957 aerial photograph, a steep-walled, snow and ice pit, 20-30 m (65-100 ft) wide, is located in the ice cap near the base of the north summit crater wall. No open water can be seen in the bottom of the pit, however, several dark patches occur and could possibly represent warm bedrock.\r\n   \"AVO interprets this 2004 period of elevated seismicity and heat flux, summit melting, debris flow generation, and magmatic gas emission from both Spurr and Crater Peak to be the result of new injection of magma to a shallow level beneath the Spurr edifice (Power, 2004; Power and others, 2004). Magmatic gas flux from both Crater Peak and Mount Spurr suggests an open connection to the surface from the zone of intrusion or magma storage along two conduits. An alternative interpretation invokes release of volatiles from the still-cooling intrusions from the 1992 eruption series (Power and others, 1998; 2002).\r\n   \"Mount Spurr remained at Level of Concern Color Code YELLOW through the end of the year. Nearly all information release statements, weekly summaries, and daily status reports emphasized that despite the departure from background activity at Spurr, there were no signs of imminent eruptive activity. As part of this response, AVO mounted a number of observation flights, gas measurement and FLIR imaging flights, increased the frequency of satellite analysis, and installed six new seismometers and 3 permanent, continuous GPS receivers to improve seismic monitoring and track deformation of the volcanic edifice. On October 8, AVO announced the public availability of Internet web camera images of Mount Spurr on the AVO web site (http://www.avo.alaska.edu).\r\n   \"AVO issued three Information Releases on Mount Spurr activity in 2004 in addition to summarizing the Spurr situation in standard weekly updates on all Alaskan volcanoes. A number of articles appeared in the Anchorage Daily News (Anchorage Daily News 2004). In response to the YELLOW Level of Concern Color Code declaration, NWS issued a one-time Volcanic Ash Advisory (VAAS) and the FAA issued a Notice to Airmen (NOTAM) on July 26. The NOTAM was cancelled on November 9 (NOTAM 4/2284; B. Brown, FAA, pers. commun., 2005).\"\r\n   From McGimsey and others (2007): \"During 2005, elevated seismicity continued beneath Mt. Spurr, and the summit ice-collapse pit enlarged - becoming a large cauldron - as heat was supplied to the summit area.  The lake changed in size, and the amount of ice debris on the lake varied.  Lake level declined in May, seemingly associated with the generation of a small debris flow on the upper southeast flank.  With the decline in water level, subaqueous fumaroles emerged and the area of hot, steaming wall rock increased.  Temperatures of the warm zones measured with Forward-Looking Infrared Radiometer (FLIR) increased somewhat over the year.  Emissions of CO2 and SO2 decreased.  The Level of Concern Color Code for Mount Spurr remained at Yellow for all of 2005 (see table 6 in original text).\"\r\n   Neal and others (2009) report that the\"Level of Concern Color Code for Mount Spurr at the beginning of 2006 was YELLOW due to continued above-background seismicity, magmatic degassing, and the presence of an open, warm lake within a 300-m-diameter (980 ft) rock- and ice-walled cauldron atop the summit cone. Following months of no significant change in activity, AVO downgraded the Level of Concern from YELLOW to GREEN on February 21 [2006]. The information release cited a steady decrease in shallow seismicity between April and June 2005, after which earthquake activity remained slightly elevated above background levels through the remainder of 2005 and into 2006. By May 2006, seismicity at Mount Spurr ahd returned to background levels and remained there with few exceptions through the end of 2006. Intermittent observations permitted sporadic documentation of ongoing changes in the summit area as the geothermal activity continued to disrupt the ice field around the summit cone [see table 5 in original text].\"","StartYear":2004,"StartMonth":7,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2006,"EndMonth":2,"EndDay":null,"EndTime":null,"EndQualifier":2,"EndQualifierUnit":"Months","Volcano":"Spurr","ParentVolcano":"Spurr","VolcanoID":"ak260","ParentVolcanoID":"ak260"},{"ID":593,"Name":"Aniakchak 2004/12","Description":"   From McGimsey and others (2007): \"Beginning in mid-December 2004 and continuing into January 2005, several series of 10-20 low-frequency seismic events showed up on the Aniakchak seismic network.  On January 11, 2005, returning form an observation flight over nearby Veniaminof Volcano AVO staff photographed a partially ice-free Surprise Lake wihtin the Aniakchak caldera (see fig. 29 in original text).  A thermal anomaly of unknown source was detected in satellite data on February 1-3, 2005. Subsequent analysis and discussion among AVO scientists regarding these phenomena concluded that nothing unusual was likely occurring, and no further activity was noted in succeeding months.\"","StartYear":2004,"StartMonth":12,"StartDay":15,"StartTime":null,"StartQualifier":14,"StartQualifierUnit":"Days","EndYear":2005,"EndMonth":2,"EndDay":3,"EndTime":null,"EndQualifier":1,"EndQualifierUnit":"Months","Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":4849,"Name":"Akutan non-eruptive activity 2005","Description":"From Cameron and others, 2023: \"In 2018, Akutan Volcano continued its long-term reinflation, which AVO has recorded since the installation of a GPS network at the volcano in 2005. The deformation was slightly faster in 2018 compared to its long-term rate. DeGrandpre and others (2017) noted that inflation at Akutan Volcano is episodic and suggested a shallow magma reservoir resides 6-10 km [3.7-6.2 mi] beneath the volcano. Continued inflation of the volcano is consistent with an ongoing accumulation of magma at shallow levels. The Aviation Color Code and Volcano Alert Level for the volcano remained at GREEN and NORMAL throughout 2018.\"\r\n\r\nFrom Orr and others, 2023: \"In prior years, activity at Akutan Volcano was characterized by a pattern of long-term reinflation, first observed after AVO field crews installed a Global Positioning System (GPS) network on the volcano in 2005. In 2019, however, the volcano deviated from this long-term trend by showing no systematic deformation that could be confidently linked to a volcanic source.\"","StartYear":2005,"StartMonth":1,"StartDay":1,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"Years","EndYear":2019,"EndMonth":7,"EndDay":1,"EndTime":null,"EndQualifier":6,"EndQualifierUnit":"Months","Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":533,"Name":"Veniaminof 2005/1","Description":"   From McGimsey and others (2007): \"After almost 4 quiet months, on January 4, 2005, AVO received a pilot report of small bursts of ash from the active cone rising a few hundred meters and drifting east, producing a narrow spoke-like deposit on snow within the caldera (see figs. 31 and 32 in original text).  This activity seemingly correlated with a period of continuous tremor recorded on the local seismic network that day, and a weak thermal anomaly was detected in an AVHRR satellite image.  AVO upgraded the Level of Concern Color Code for Veniaminof from Green to Yellow. AVO seismologists noticed that weak seismic tremor had begun on January 1 and increased over the subsequent week to levels last observed in May-June 2004.  Steam and ash emissions continued from the next several days and residents of Perryville, located 35 km (22 mi) south of Veniaminof, reported incandescence; the caretaker a ta local hunting lodge located west-southwest of the volcano reported seeing intermittent bursts of steam and ash.  Beginning on January 8, a persistent thermal anomaly began appearing in satellite images.  Then, on January 10, following nearly 48 hours of minor but nearly continuous ash emissions - some bursts reaching to 13,000 ft (3,692 m) above sea level - AVO raised the Level of Concern from Yellow to Orange.  The maximum amplitude of the seismicity had by then slightly exceeded that observed during the previous phase of unrest, which ended in September 2004.  AVO launched an overflight on January 11.  The crew observed nearly continuous low-level ash and steam emission from the central cone and much of the caldera was thinly covered in ash (see fig. 33 in original text).\r\n   \"Seismic data, web camera views, and satellite images indicated that low-level ash emissions continued for the next 5 weeks.  The seismicity was characterized by low-amplitude tremor with occasional larger bursts.  Weather permitting, satellite views showed anomalous heat at the summit cone consistent with hot blocks and ash ejection from the vent.  The web camera showed intermittent ash clouds with the highest reaching almost to 13,000 ft (4,000 m) ASL.  Strombolian eruptive activity was visible to the residents of Perryville during the night of February 3.  Then during the week of February 25, seismicity decreased substantially and only minor emissions of steam were observed.  AVO reduced the Level of Concern from Orange to Yellow.  By the end of the following week, volcanic tremor had subsided and seismic activity was deemed to be at background levels and the Level of Concern was reduced from Yellow to Green (see table 6 in original text).\r\n   Excerpts from AVO's information releases during this Veniaminof eruption are available online at: \u003ca href=\"http://www.avo.alaska.edu/archives/veniaminof2005/\"\u003ehttp://www.avo.alaska.edu/archives/veniaminof2005/\u003c/a\u003e\r\n   The Smithsonian Institution's Global Volcanism Bulletin (v. 30, n. 2) summarizes the event as follows: \"AVO raised the Concern Color Code at Veniaminof from Green to Yellow on 4 January because around that time several small ash emissions from the volcano's intracaldera cone were observed on the web camera in Perryville. Ash emissions were visible starting around 0938, but may have been obscured by meteorological clouds in previous images. The discrete ash emissions were small, rose hundreds of meters above the cone, and dissipated as they drifted E. Minor ash fall was probably confined to the summit caldera. Very weak seismic tremor was recorded beginning on 1 January, and increased slightly over the next 2 days. These seismic signals were similar to those recorded during steam-and-ash emissions in April to October 2004. However, there were no indications from seismic data that events significantly larger than those observed around 4 January were imminent.\r\n   \"AVO raised the Concern Color Code at Veniaminof from Yellow to Orange on 10 January as ash emissions from the volcano's intracaldera cone reached heights of nearly 4 km during 8-10 January [see figure 11 in original online source].  Seismicity remained at elevated levels and satellite images showed a persistent thermal anomaly at the intracaldera cone. On 11 January, the Anchorage VAAC again reported emission of a thin ash cloud to ~ 3 km altitude visible on the Perryville web camera. On 12 January the Anchorage VAAC reported emission of a thin ash cloud, visible on the Perryville web camera, that rose to 3-4 km altitude, extended ENE, and dissipated within ~ 55 km of the volcano. On 14 January, a satellite image showed a thermal anomaly in the vicinity of the Veniaminof summit. Although the anomaly appeared less intense than when first detected on 8 January and volcanism seemed to have declined significantly since 12 January, activity still remained significantly higher than normal with occasional bursts of volcanic tremor.\r\n   \"During the rest of the month of January, seismic data, web camera views, and satellite images indicated that low-level ash emissions continued at Veniaminof. Seismicity was similar to levels observed during the previous week, consisting of low-amplitude volcanic tremor with occasional larger bursts. During clear weather, satellite imagery showed anomalous heat at the summit cone, consistent with hot blocks and ash being ejected from the active vent. In addition, the web camera showed intermittent ash plumes reaching as high as 3 km altitude. Occasional stronger bursts of seismic tremor during 20-21 January and around 28 January may have indicated plumes to higher levels, but not above 4 km altitude. Veniaminof remained at Concern Color Code Orange.\r\n   \"Activity during February 2005. On the evening of 3 February, Strombolian activity at Veniaminof was visible by residents of Perryville ~ 30 km from the volcano. Activity was also observed on web camera views and seen by satellite as an increase in radiated surface heat. An increase in seismicity suggested that Strombolian activity may have continued through 4 February while the volcano was obscured by clouds.\r\n   \"During 28 January to 4 February, seismicity at Veniaminof was similar to levels for the previous week, with low-amplitude tremor and occasional larger bursts. During clear weather, satellite imagery showed anomalous heat at the summit cone, consistent with hot blocks and ash being ejected from the active vent. The web camera showed intermittent ash plumes reaching as high as 3 km altitude. Veniaminof remained at Concern Color Code Orange.\r\n   \"Low-level Strombolian eruptive activity continued at Veniaminof during 4-11 February. On 9 February, an ash burst rose hundreds of meters above the intracaldera cone. Satellite images continued to show a thermal anomaly in the vicinity of the intracaldera cone, consistent with the presence of hot material at the vent. Seismicity remained above background levels at the volcano. On the morning of 10 February there was a distinct increase in the amplitude and frequency of earthquakes. The increase continued through 11 February. This activity was consistent with more energetic explosions from the active cone, but there were no indications that the bursts rose higher than 4 km altitude. Veniaminof remained at Concern Color Code Orange.\r\n   \"During 11-18 February, it was likely that low-level Strombolian eruptive activity continued at Veniaminof based on seismic data and satellite imagery. Cloudy conditions obscured web camera views of the volcano, and no ash emissions were observed above the cloud cover. Seismicity remained above background levels at Veniaminof. The character of the seismicity changed slightly during the report period, with frequent periods of continuous banded volcanic tremor occurring, but the amplitudes of earthquakes did not increase. This activity was consistent with explosions from the active cone; however, there was no indication that these bursts rose more than 4 km altitude. Veniaminof remained at Concern Color Code Orange.\r\n   \"Seismicity decreased substantially at Veniaminof during 18-25 February in comparison to previous weeks, leading AVO to decrease the Concern Color Code from Orange to Yellow. Periods of volcanic tremor diminished, and no discrete events associated with ash bursts had occurred for several days. Only minor steam emissions were seen. AVO received no reports of ash emissions from pilots or ground observers. AVO concluded that given the decline in seismicity, it appeared that the most recent episode of Strombolian eruptive activity at Veniaminof had ended.\r\n   \"Activity during March 2005. A further reduction in activity at Veniaminof during 25 February to 4 March led AVO to reduce the Concern Color Code from Yellow to Green, the lowest level. For more than a week seismic activity was at background levels, periods of volcanic tremor had ceased, and there were no discrete events associated with ash bursts. Only minor emissions of steam were observed on the web camera and satellite imagery. AVO received no reports of ash emissions from pilots or observers on the ground. They concluded that given the decline in seismicity it appeared that the most recent episode of eruptive activity had ended at Veniaminof.\"","StartYear":2005,"StartMonth":1,"StartDay":4,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2005,"EndMonth":2,"EndDay":25,"EndTime":null,"EndQualifier":7,"EndQualifierUnit":"Days","Volcano":"Veniaminof","ParentVolcano":"Veniaminof","VolcanoID":"ak301","ParentVolcanoID":"ak301"},{"ID":532,"Name":"Korovin 2005/2","Description":"   From McGimsey and others (2007): \"On the morning of February 24, 2005, AVO received a report from residents of Atka Village that Korovin had erupted the previous evening, producing a large steam and ash cloud.  February 23 was a clear day and local residents had noticed minor steaming from Korovin about noon (see fig. 40 in original text).  Then, about 7 p.m. HST (8 p.m. AST), they witnessed a dark plume over Korovin, rising several thousand feet high, drifting east, that had ash visibly falling out near the base, presumably confined to the flanks of Korovin (see fig. 41 in original text).  Several minutes later, three or four smaller, gray puffs occurred. Although they watched, no further activity ensued during the calm, clear, moonlit night.\r\n   \"Satellite data from about the time of the reported activity indicated the presence of a 1-2 pixel thermal anomaly and a small steam plume, possibly with localized minor ash.  Height of the steam plume was estimated to be about 10,000 ft (~3 km), corroborating the observer account.  AVO issued an Information Release on February 24 and raised the Level of Concern Color Code to Yellow.  With no further reports of continuing activity, nothing evident in subsequent satellite data, and no unusual seismicity from a seismic station in Atka Village, AVO reduced the Color Code from Yellow to UA in the March 4, 2005, Weekly Update (see table 6 in original text).  Evidence of similar activity has been identified in 2002 and 2004 satellite images and observed by field crews in 2004 (see fig. 42 in original text).\r\n   \"A PIREP of steam reaching several thousand feet above Korovin on March 19 was the next report of activity, and then in early May observational data indicated that the lake had drained in the south summit crater of Korovin and that incandescence was visible in the about 100-m (~325 ft) - wide pit.  The next several months were quiet.","StartYear":2005,"StartMonth":2,"StartDay":23,"StartTime":"19:00:00","StartQualifier":null,"StartQualifierUnit":null,"EndYear":2005,"EndMonth":5,"EndDay":7,"EndTime":null,"EndQualifier":14,"EndQualifierUnit":"Days","Volcano":"Korovin","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak171","ParentVolcanoID":"ak17"},{"ID":601,"Name":"Martin 2005/2","Description":"   From McGimsey and others (2007): \"On February 26 [2005], AVO received from the Center Weather Service Unit (CWSU) several pilot reports of a steam cloud rising to 12,000 ft (3,360 m) from Katmai.  An inspection of the webicorders, spectrograms, and satellite logs revealed nothing unusual.  Because Katmai Volcano does not have active fumaroles, the reported activity was attributed to nearby Mounts Mageik or Martin, both of which have active fumaroles that frequently produce noticeable steam plumes.  Nonvolcanic meterological phenomena that commonly are mistaken for volcanic activity also are common in this area.\"","StartYear":2005,"StartMonth":2,"StartDay":26,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2005,"EndMonth":2,"EndDay":26,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Martin","ParentVolcano":"Martin","VolcanoID":"ak189","ParentVolcanoID":"ak189"},{"ID":602,"Name":"Mageik 2005/2","Description":"   From McGimsey and others (2007): \"On February 26 [2005], AVO received from the Center Weather Service Unit (CWSU) several pilot reports of a steam cloud rising to 12,000 ft (3,360 m) from Katmai.  An inspection of the webicorders, spectrograms, and satellite logs revealed nothing unusual.  Because Katmai Volcano does not have active fumaroles, the reported activity was attributed to nearby Mounts Mageik or Martin, both of which have active fumaroles that frequently produce noticeable steam plumes.  Nonvolcanic meterological phenomena that commonly are mistaken for volcanic activity also are common in this area.\"","StartYear":2005,"StartMonth":2,"StartDay":26,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2005,"EndMonth":2,"EndDay":26,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mageik","ParentVolcano":"Mageik","VolcanoID":"ak187","ParentVolcanoID":"ak187"},{"ID":595,"Name":"Pavlof 2005/4","Description":"   In April and May, 2005, fumarolic activity at nearby Mount Hague was erroneously reported as plumes emanating from Pavlof.  See \u003ca href=\"http://www.avo.alaska.edu/volcanoes/volcact.php?volcname=Emmons%20Lake%20Volcanic%20Center\u0026eruptionid=594\u0026page=basics\"\u003ehttp://www.avo.alaska.edu/volcanoes/volcact.php?volcname=Emmons%20Lake%20Volcanic%20Center\u0026eruptionid=594\u0026page=basics\u003c/a\u003e for more information.","StartYear":2005,"StartMonth":4,"StartDay":16,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2005,"EndMonth":5,"EndDay":24,"EndTime":null,"EndQualifier":7,"EndQualifierUnit":"Days","Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":594,"Name":"Hague, Mt 2005/4","Description":"   From McGimsey and others (2007): \"National Weather Service personnel in Cold Bay reported a steam plume emanating from the side of Pavlof on April 16, 2005.  Subsequent analysis of the photographs sent to AVO indicated that the steam cloud originated instead from adjacent Mount Hague (see fig. 35 in original text), possibly from the fumarolic field located on the south flank - instead of the crater lake - based on the plume position; however, no direct observations confirmed the source.  Seismicity was determined to be normal.\r\n   \"On May 23 and 24, 2005, observations of steam - this time possibly containing some ash - rising to as much as 3,000 ft (~900 m) above Pavlof were again reported to AVO, as well as to FAA and AAWU.  Photographs revealed that the plume originated instead from Mount Hague (see fig. 36 in original text).  Analysis of satellite images revealed no evidence of ash, and no unusual seismicity was recorded.  One of the two summit craters on Mount Hague contains vigorous fumaroles and has produced strong steam emissions in previous years (see table 7 in original text).  The activity was interpreted to result from normal fluctuation of the hydrothermal system at Mount Hague and was reported in the AVO Weekly Update on May 27, 2005.\"","StartYear":2005,"StartMonth":4,"StartDay":16,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2005,"EndMonth":5,"EndDay":24,"EndTime":null,"EndQualifier":7,"EndQualifierUnit":"Days","Volcano":"Hague, Mt","ParentVolcano":"Emmons Lake Volcanic Center","VolcanoID":"ak113","ParentVolcanoID":"ak93"},{"ID":536,"Name":"Cleveland 2005/4","Description":"   From McGimsey and others (2007): \"After several years of quiescence following an explosive eruption in 2001, AVO remote sensors observed a 3-pixel thermal anomaly at the summit of Cleveland on March 13, 2005 (see fig. 38 in original text).  On April 27, 2005, the FAA alerted AVO of a pilot report of eruptive activity - \"ash cloud * * * 15,000 to 18,000 ft high\" - in the vicinity of Cleveland (based on coordinates from the pilots).  Satellite images showed no evidence of activity.  AVO seismologists checked seismic data from the nearest stations (Nikolski, located 75 km [45 mi] east, and at Okmok Volcano, 150 km [93 mi} east of Cleveland), and found nothing unusual.  CWSU issued a one-time Urgent Pilot Report, and AAWU issued a one-time SIGMET.  Although time-series thermal data did not record any evidence of activity, short-lived minor explosive activity would not be considered unusual for Cleveland and could go undetected if it occurred during periods between acquisitions of satellite images or if concealed within the frequent cloud cover.\r\n   \"Following the detection of a 1-pixel thermal anomaly at the summit on June 28, evaluation of before and after satellite images suggested the presence of a lahar deposit on the northeast flank, inferring that minor activity persisted at Cleveland.  Then, on July 5, the entire upper flanks of the volcano were observed dusted with ash in a satellite image (see fig. 39 in original text).  AVO rasied the Level of Concern Color Code from Unassigned (UA) to Yellow in an Information Release on July 7, 2005 (see table 6 in original text).  The presence of ash, minor blocky avalanche-like deposits, and thermal anomalies was consistent with low-level Strombolian eruptive activity (D. Schneider, AVO logs). \r\n   \"Thereafter, although a thermal anomaly was observed on August 11, the activity appeared to wane.  AVO reduced the Color Code from Yellow back to UA on August 27.  But the volcano remained restless, and a summit thermal anomaly again was observed on August 31.  By mid-September, AVO was ready to test a new automated system that detects thermal anomalies and raises an alert.  On September 21, this new system successfully detected a thermal anomaly at the summit of Cleveland.  For the next few weeks, the volcano remained quiet.  Then, on the morning of October 7, AVO detected in satellite images a small drifting ash cloud located about 150 km (90 mi) east-southeast of Dutch Harbor.  On the basis of regional seismic data at Nikolski (75 km [45 mi] east of the volcano), and backtracking the ash cloud, AVO concluded that a small eruption had occurred at Cleveland at approximately 01:45 ADT (0945 UTC).  AVO and the NWS worked together to determine that the ash cloud was at an altitude of no more than 15,000 ft (4,600 m).  No ash fell in Nikolski.  AVO immediately raised the Color Code from UA to Orange and NWS issued a SIGMET indicating that the ash cloud was moving east.  The next day, October 8, ther was no sign of ash emission or a summit thermal anomaly, and on October 10 the Color Code was downgraded from Orange to Yellow.  The last thermal anomaly was seen on November 6, and steam plumes were occasionally visible in satellite data for the next several weeks.  Because there was no evidence of ash emissions on November 25, AVO reduced the Color Code for Cleveland from Yellow to UA.  As fate would have it, a few days later, evidence for minor eruptive activity was observed; however, the activity did not continue and the volcano remained quiet for the rest of the year.  AVO issued five special Information Releases about Cleveland activity between July 7 and November 25, 2005.\"\r\n    A chronology of this event is available at: \u003ca href=\"http://www.avo.alaska.edu/archives/Cleveland2005.php\"\u003ehttp://www.avo.alaska.edu/archives/Cleveland2005.php\u003c/a\u003e\r\n   From the Smithsonian Institution (2005): \"Mount Cleveland produced significant ash plumes during March 2001 (BGVN 26:04). Volcanic unrest continued through 4 May 2001, and signals consistent with volcanic seismicity were detected by an Alaska Volcano Observatory (AVO) seismic network 230 km E. By the end of May, neither eruptive activity nor thermal anomalies were observed. Until July 2005, no alert level was assigned, and AVO monitoring produced no reports on Cleveland.\r\n   \"Cleveland lacks a real-time seismic network. Accordingly, even during times of perceived quiet there is an absence of definitive information that activity level is at background. AVO's policy for volcanoes without seismic networks is to not get assigned a color code of Green.\r\n   \"Satellite imagery of Cleveland taken during 24 June to 1 July 2005 showed increased heat flow from the volcano and a possible debris flow. AVO stated that although observations were inhibited by cloudy weather, they indicated the possibility of increased volcanic activity. AVO did not assign a Concern Color Code to Cleveland due to the lack of seismic monitoring and limited satellite observations.\r\n   \"Satellite images during 1-8 July showed increased heat flow, thin ash deposits, and possible debris flows extending ~ 1 km down the flanks from the summit crater. AVO assigned a Concern Color Code of Yellow on 7 July. On 18 July satellite imagery showed steam emanating from Cleveland's summit and evidence of minor ash emissions. Meteorological clouds obscured Cleveland during the third week of July. During 22-29 July satellite images showed minor steaming from the summit, possible fresh localized ash deposits, and a weak thermal anomaly.\r\n   \"On 4 August satellite images showed a thermal anomaly. On 27 August AVO reduced the Concern Color Code at Cleveland from Yellow to \"Not Assigned\" because there had been no evidence of activity since a thermal feature was observed on satellite imagery from 11 August. A thermal feature was detected on several satellite images obtained on 31 August, and one on 19 September, but there was no evidence of eruptive activity.\r\n   \"On 7 October, AVO raised the Concern Color Code to Orange after detecting a small drifting volcanic ash cloud. The cloud was seen in satellite data at a spot ~ 150 km ESE of Dutch Harbor at 1700 UTC. Based on data from a regional seismometer at Nikolski, AVO concluded that the ash came from a small Cleveland eruption at approximately 0145. AVO, in consultation with the National Weather Service, estimated the top of the ash cloud to be no more than 4,600 m altitude. The ash cloud dissipated and was not detected via satellite after 1800 UTC. Three days passed during which there were no new observations of eruptive activity at Cleveland from satellite data, pilots, or ground-based observers. Accordingly, on 10 October the Concern Color Code was reduced to Yellow.\"","StartYear":2005,"StartMonth":4,"StartDay":27,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2005,"EndMonth":9,"EndDay":27,"EndTime":null,"EndQualifier":3,"EndQualifierUnit":"Months","Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":535,"Name":"Chiginagak 2005/5","Description":"   From McGimsey and others (2007): \"Between November 2004 and early May 2005, a flux of heat to the summit area caused melting of more than 1.3x10^7 cubic m (4.6x10^8 cubic ft) of ice and snow filling the summit crater of Chiginagak, resulting in a 400-m wide (~1,300 ft) and 105-m deep (~350 ft) cauldron containing an acidified lake (Schaefer and others, 2005; J.R. Schaefer and others, AVO/ADGGS, written commun.,  2007) (see figs. 25 and 26 in original text).  In early May 2005, a catastrophic release of sulfurous, clay-rich debris and acidic water from the lake, with an accompanying acidic aerosol component, traveled 27 km (~17 mi) downstream and flowed into the Mother Goose Lake, headwaters of the King Salmon River (see figs. 27 and 28 in original text).  Extensive vegetation damage occurred along the flood route and Mother Goose Lake was acidified (pH of 2.9-3.1), killing all aquatic life and preventing the annual salmon run (J.R. Schaefer and others, AVO/ADGGS, written commun., 2007).  AVO volcanologists were to begin the second summer of geologic mapping and hazard assessment at the volcano, but instead responded by documenting the flooding and damage, collecting water samples, measuring water temperature, conductivity, and pH, and surveying the extensive vegetation damage with a U.S. Fish and Wildlife Service botanist.  A data-logging seismometer was deployed for about one month with no significant seismicity recorded; Chiginagak currently does not have a seismic network.\r\n   \"AVO issued an Information Release about the activity on August 23, 2005, shortly after the field crew arrived on site, and an account was related in the Weekly Update (August 26).  A summary of preliminary findings is presented by Schaefer and others (2005).\"\r\n   In the August 23, 2005 Information Release, AVO reported: \"An AVO field crew reports that a 1,300 ft (400 m) wide melt-water lake has formed in the snow and ice filled summit crater at Chiginagak Volcano sometime since the last observations in August 2004. Sometime earlier this summer, the southern crater rim of Chiginagak was breached, allowing a portion of the lake to drain. The resulting lahar (a debris flow consisting of a mixture of volcanic sediment, water, and ice) left a deposit on the unnamed glacier draining the crater to the south and caused flooding of 3 to 6 ft (1 to 2 m) above normal on Indecision Creek. Volcano Creek and Mother Goose Lake, the headwaters of King Salmon River, were affected as well. Floodwaters also flowed on and through Chiginagak's southeast glacier, spilling out into an unnamed Pacific drainage leading to Chiginagak Bay. The lahar likely contained acidic water. Although we have no direct samples of the summit lake water, measurements from crater lakes at similar volcanoes have shown pH values ranging from 0 to 3, the acidity arising mainly from sulfuric acid. Vegetation damage was observed along Indecision Creek and the unnamed Pacific drainage.\r\n   \"The breach in the crater rim and the ensuing lahar probably occurred in July 2005; reports from Painter Creek Lodge at this time tell of strong sulfur smells and cloudy, yellowish water in the Indecision Creek drainage.\r\n   \"AVO geologists continue to investigate the event and its impacts. There are no indications that an eruption is imminent or that this event is necessarily precursory to an eruption.\"\r\n   Follow-up studies of the area in 2006 revealed that the drainage is still acidic.","StartYear":2005,"StartMonth":5,"StartDay":null,"StartTime":null,"StartQualifier":3,"StartQualifierUnit":"Months","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Chiginagak","ParentVolcano":"Chiginagak","VolcanoID":"ak49","ParentVolcanoID":"ak49"},{"ID":592,"Name":"Iliamna 2005/5","Description":"   From McGimsey and others (2007): \"On May 15, 2005, AVO seismologists noted a swarm of unusual seismic activity at Iliamna.  The events were emergent and prolonged (longest lasted 5-8 minutes), and were strongest at seismic station ILS, located on the south flank of South Twin (see fig. 14 in original text).  The activity began about 1250 UTC and tapered off at 1718 UTC.  Analysis revealed that the signals most likely were caused by a surficial process, such as a snow avalanche - a common occurrence on Iliamna - but this particular event lacked the usual precursory seismicity preceding other Iliamna snow and ice avalanches (J. Caplan-Auerbach and others, 2004; J. Caplan-Auerbach, written commun., 2005; Caplan-Auerbach and Huggel, 2007.)  Corroborating evidence arrived on the morning of May 17 when Lee Fink of Lake Clark National Park called AVO to offer his observations from an overflight of the area the previous day.  Fink reported seeing a large, fresh rock slide (not a snow or ice avalanche) southeast of Iliamna that began about the 6,500-ft level on the southeast flank of South Twin and ran down to about the 1,200-ft elevation (see fig. 15 in original text).  The lengthy ridge extending south of Iliamna that includes South and North Twins and a large unnamed massif has steep, exposed sections of bedrock that frequently generate rock falls, and occasionally large rockslides, such as occurred on May 15 at South Twin.\"","StartYear":2005,"StartMonth":5,"StartDay":15,"StartTime":"00:50:00","StartQualifier":null,"StartQualifierUnit":null,"EndYear":2005,"EndMonth":5,"EndDay":15,"EndTime":"17:18:00","EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":600,"Name":"Trident 2005/6","Description":"   From McGimsey and others (2007): \"AVO Coordinating Scientist John Eichelberger was leading an annual student fieldtrip into the Valley of Ten Thousand Smokes (VTTS) in June 2005 when, from the rim of Trident Volcano, he observed a new crater about 50 m (165 ft) in diameter.  Eichelberger has traversed the VTTS for many years and verified that the crater was not present during his 2003 trip; clouds prevented viewing the area of the crater in 2004.  Although no anomalous seismicity was noted in the Katmai area in 2003 and 2004, a period of tremor-like signal occurred in the Katmai area on April 27 as noted in the AVO Seismic Logs.  No correlation has been determined.\"","StartYear":2005,"StartMonth":6,"StartDay":null,"StartTime":null,"StartQualifier":2,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Trident","ParentVolcano":"Trident","VolcanoID":"ak288","ParentVolcanoID":"ak288"},{"ID":598,"Name":"Kasatochi 2005/7","Description":"   From McGimsey and others (2007): \"In late July 2005, AVO was contacted by Vern Byrd of U.S. Fish and Wildlife Service (USFWS)/Homer who passed along a report from a USFWS field camp on Kasatochi Island, located about 50 km (~30 mi) east of Great Sitkin and about 100 km (~60 mi) west of Korovin Volcano.  On June 23, members of the field party viewed the lake and noticed nothing unusual.  Then, on July 27, the same field party peered into the summit crater from the rim and saw the lake 'simmering, not quite a roiling boil, concentrated in a few patchy areas, bubbling more violently in the western half of the lake, * * * lake appeared thin (sic), no steam observed at all.'  The bubbling areas were intermittent.  The observers did not feel vibrations or earthquakes or hear anything odd, nore did they detect unusual odors or water discoloration (the lake typically is turbid and turquoise in color).  Gulls landed unperturbed on the water surface.  The observers concluded that what they were seeing was a distinct change from the previous month and from conditions present during the past several years on the island.\r\n   \"Biologists visited the crater rim again on August 1 and reported no significant change from the activity reported on July 27.  They mentioned that the lake was perhaps 'simmering a little less with less area of the lake affected.'  A check of satellite imagery for any sign of thermal anomaly or other change during this time period came up negative, however, clear views of this frequently cloud-covered small island were few (ASTER, Landsat, R. Wessels, USGS/AVO, oral commun., 2005).\r\n   \"A USGS-contracted helicopter in Adak transported an AVO geologist and the USFWS field party chief Brie Drummond to Kasatochi on September 2 to investigate.  Winds were high and fog and clouds intermittently obscured the summit crater rim.  During one low pass over the lake, no signs of bubbling or upwelling were observed.  Two patches of brown scum 2-3 m (6.5-10 ft) across floated in the approximate area where bubbling was observed earlier in the summer (see fig. 44 in original text).  No signs of recent lake level disturbance or hydrothermal activity were noted.\"","StartYear":2005,"StartMonth":7,"StartDay":27,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2005,"EndMonth":9,"EndDay":null,"EndTime":null,"EndQualifier":28,"EndQualifierUnit":"Days","Volcano":"Kasatochi","ParentVolcano":"Kasatochi","VolcanoID":"ak146","ParentVolcanoID":"ak146"},{"ID":534,"Name":"Veniaminof 2005/9","Description":"   From McGimsey and others (2007): \"Veniaminof remained relatively quiet [since February, 2005] until early September when several minor bursts of ash were observed by Perryville residents and visible on the web camera (see fig. 34 in original text).  This and an increase in seismicity prompted AVO to elevate the Level of Concern from Green to Yellow on September 7.  The minor unrest continued only for a couple of weeks when seismicity once again decreased to background level and there were no observations of emissions.  AVO reduced the Level of Concern from Yellow to Green on September 28.\r\n  \"Then, on November 4, a low-level, minor ash emission visible in the webcam prompted AVO to raise the Level of Concern from Green to Yellow.  Slightly elevated seismicity persisted for the next few weeks but poor weather conditions precluded visual observations.  By mid-December, seismic levels were again down to background level, and on December 30, the Level of Concern was downgraded from Yellow to Green, the 8th Color Code change of the year for Veniaminof (see table 6 in original text).\"\r\n   From the Smithsonian Institution (2006, v. 31, n. 3): \"On 7 September 2005, the Alaska Volcano Observatory (AVO) noted several minor bursts of ash from the volcano during the afternoon. Ash bursts continued to occur through at least 9 September, with ash rising less than 3 km altitude, and with the ash confined to the caldera. Over the following 2 weeks, minor ash emission continued at a rate of 1-5 events per day based on interpretations of seismic data. AVO reported that it was likely that diffuse ash plumes rose to heights less than ~ 3 km and were confined to the summit caldera. Cloudy weather during 16-23 September prohibited web-camera and satellite observations of Veniaminof, but seismic data indicated diminishing activity. On 28 September seismicity had remained at background levels for over a week, and there was no evidence to suggest that minor ash explosions were continuing.\r\n   \"On 4 November 2005, a low-level minor ash emission occurred from the intracaldera cone beginning at 0929. Ash rose a few hundred meters above the cone, drifted E, and dissipated rapidly. Minor ashfall was probably confined to the summit caldera. During the previous 2 weeks, occasional steaming from the intracaldera cone was observed. Very weak seismic tremor and a few small discrete seismic events were recorded at the station closest to the active cone. However, AVO reported that there were no indications from seismic data that a significantly larger eruption was imminent.\"\r\n   Execerpts from AVO's weekly updates and information releases for this time period can be found at this website: \u003ca href=\"http://www.avo.alaska.edu/archives/Veniaminof_2005_09.php\"\u003ehttp://www.avo.alaska.edu/archives/Veniaminof_2005_09.php\u003c/a\u003e.","StartYear":2005,"StartMonth":9,"StartDay":7,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2005,"EndMonth":11,"EndDay":4,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Veniaminof","ParentVolcano":"Veniaminof","VolcanoID":"ak301","ParentVolcanoID":"ak301"},{"ID":597,"Name":"Korovin 2005/9","Description":"   From McGimsey and others (2008): \"On September 13, 2005, a long sequence of strong seismicity was recorded on the newly operational Korovin seismic network.  The sequence began with two small local events followed by about 30 minutes of weak tremor, and then about 20 weak local events.  Nothing unusual was detected on satellite images of the time period.\r\n   \"Although a network of seismic stations was installed on northern Atka Island during the summer of 2004, data were not accessible until early March 2005, and Korovin was not considered to be seismically monitored until late 2005 - announced in the December 2, 2005, Information Release - when a sufficient period of background seismicity had been recorded, and equipment/communications problems resolved (see table 1 in original text).  On December 2, Korovin, which previously had been listed as UA, was formally assigned Color Code Green.\"","StartYear":2005,"StartMonth":9,"StartDay":13,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2005,"EndMonth":9,"EndDay":13,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Korovin","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak171","ParentVolcanoID":"ak17"},{"ID":3471,"Name":"Steller 2005/9","Description":"From Huggel (2009): \"One of the largest rock-ice avalanches in the past several decades occurred on Mt. Steller in south-central Alaska (3236 m asl, 60 degrees 13 minutes N, 143 degrees 05 minutes W) on September 14, 2005. The headscarp of the avalanche is located at 3100 m asl in the glacier-covered south flank of Mt. Steller. The total volume of rock and ice that failed and was entrained along the avalanche path is 40-60x10^6 m cube. The avalanche traveled 9 km and came to rest on Bering Glacier (Fig. 7 [in original text]; Huggel and others, 2008). Tertiary sedimentary rocks layered sub-parallel to the surface slope characterize the failure zone. Due to its remote location, the avalanche was only detected by seismic signal. The seismic impact of the slide was so strong that it was detected around the world.\"\r\nFrom Huggel and others (2012): \"Field surveys have shown that the flowing mass was composed of (i) the initial collapsing rock-ice mass estimated to be made up of 3-4.5 Mm cubed of ice, 2 Mm cubed of snow and 10-20 Mm cubed of rock [Huggel and others, 2008] and (ii) material eroded from the glacier along the avalanche path. The only available constraint on the deposit is its area, with an uncertainty of maximum 5% on the runout distance (Figure 1b [in original text])\"\r\n\"The seismic signal generated by the avalanche was recorded by 7 broadband seismic stations covering a wide range of azimuths and source-station distances (37-623 km) (Figure 1a [in original text]). Figures 1c and 1d [in original text] show the typical emergent onset of landslide generated seismic signals; the signal lasts about 130 s at BERG station. At all the stations, the spectrogram has a characteristic cigar shape with a frequency content f∈ [0.004, 1.5] Hz, similar to the seismic signal generated by the Thurwieser landslide [Favreau and others, 2010].\"","StartYear":2005,"StartMonth":9,"StartDay":14,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Steller","ParentVolcano":"Steller","VolcanoID":"ak265","ParentVolcanoID":"ak265"},{"ID":599,"Name":"Tanaga 2005/10","Description":"   From McGimsey and others (2007): \"Earthquake activity at Tanaga increased abruptly on October 1, 2005.  Over the next several days, the number of located events ranged from 15 to 68 per day, in striking contrast to the typical one earthquake per month previously recorded since the seismic network was installed in 2003.  The earthquakes centered a few kilometers northeast of the summit of Tanaga at a depth of 10-20 km (~6-12 mi), and the largest event had a magnitude of 1.7.  AVO issued a special Information Release on October 5 to announce the activity.  The activity further escalated that day and again early on October 7 with located earthquakes of magnitude 0.5-1.9 shallowing to depths of 6-12 km (~4-7.5 mi) beneath Tanaga's summit.  This change in activity prompted AVO to raise the Level of Concern Color Code from Green to Yellow on October 7, 2005.  By the following week, the daily earthquake count had fallen slightly, and by the next week, earthquake activity had diminished further, but remained above background levels.  A several-minute-long period of unusual seismicity occurred on October 17 and may have been a landslide or small phreatic explosion, but no signs of activity were visible in satellite images.  Although the daily earthquake count continued to dwindle, nearly continuous, weak volcanic tremor was recorded on seismic stations closest to nearby Takawangha Volcano on October 24 (see fig. 47 in original text).  This was the first episode of tremor recorded at the Tanaga cluster since the seismic network was installed in 2003.  Weak tremor continued for the next several weeks, gradually declining.  Seismicity continued to decline further during November, and by the end of the month the likelihood of an eruption was considered significantly decreased.  In an Information Release issued on November 25, 2005, AVO reduced the Level of Concern Color Code from Yellow to Green.\"","StartYear":2005,"StartMonth":10,"StartDay":1,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2005,"EndMonth":11,"EndDay":null,"EndTime":null,"EndQualifier":14,"EndQualifierUnit":"Days","Volcano":"Tanaga","ParentVolcano":"Tanaga","VolcanoID":"ak280","ParentVolcanoID":"ak280"},{"ID":547,"Name":"Augustine 2005/12","Description":"   From Power and others (2006): The 2006 eruption of Augustine consisted of four phases defined by the character of unrest or eruptive activity, which are described below. These phases are the precursory (May 2005 to 11 January 2006), the explosive (11 to 28 January), the continuous (28 January to 2 February), and the effusive (2 February to late March).\r\n   \"The precursory phase began as a steady increase in microearthquakes beneath the volcano, ranging from one to two per day in May 2005 to 15 per day in mid-December [see Figure 3 in original text]. In July 2005, geodetic baselines began to lengthen, indicative of pressurization at sea level centered beneath the edifice (Cervelli and others, 2006). On 2 December 2005, seismometers began recording signals from small phreatic explosions; the largest signals occurred on 10, 12, and 15 December. An overflight on 12 December revealed vigorous steaming, a new vent on the summit's southeastern side, and a dusting of ash on the volcano's southern flanks. The ash was a mix of weathered and glassy particles; the latter appear to be remobilized 1986 tephra. An explosion on 15 December disabled the telemetery for the two highest seismic stations [see figure 2 in original text].\r\n   \"Augustine then entered an explosive phase, which lasted from 11-28 January 2006. A strong swarm of volcano-tectonic (VT) earthquakes began at 0030 UTC on 11 January, culminating in explosive eruptions at 1344 and 1412 UTC. These explosions produced ash plumes, reported by the U.S. National Weather Service (NWS) to have reached heights greater than nine kilometers above sea level (asl), which moved slowly to the north and northeast. Ash sampled on 12 January was primarily dense or weathered fragments, suggesting little juvenile magma. Over the next 36 hours, several sequences of small, regularly spaced VT earthquakes, many with identical waveforms, occurred at rates as high as three to four per minute. Similar earthquakes, referred to as clones or drumbeats, have been associated at other volcanoes with the emplacement of lava domes (Dzurisin and others, 2005).\r\n   \"Monitoring instruments also recorded six powerful explosions that occurred between 1324 UTC on 13 January and 0914 UTC on 14 January [see figure 3 in original text]. The first explosion destroyed the seismometer and CGPS high on the volcano's northeastern flank [see figure 2 in original text]. Plumes reached altitudes of 14 kilometers asl and deposited traces of ash on southern Kenai Peninsula communities. Ash from these eruptions was more heterogeneous and contained dense particles as well as fresh glass shards, indicating the eruption of new magma. Satellite imagery tracked these plumes as they moved eastward and disrupted commercial airline traffic to and from Alaska.\r\n   \"A 16 January overflight revealed a small, new lava dome at the summit. An explosive eruption at 1658 UTC on 17 January sent ash to 13 kilometers asl that moved westward. The eruption left a 20- to 30-meter-diameter crater in the new dome and produced ballistic fields on the volcano's western flanks. Data transmission from the west flank CGPS station stopped coincident with this explosion [see figure 2 in original text]. Additionally, the eruptions of 13-17 January generated pumiceous pyroclastic flows, snow avalanches, and lahars that moved down the volcano's flanks [see figure 2 in original text].\r\n   \"The volcano then entered a period of more continuous eruptive activity that began at 0534 UTC on 28 January and that lasted until 2 February. The phase began with four explosive eruptions that generated ash plumes to heights of nine kilometers asl [ see figure 3 in original text]. Ash moved southward and fell in trace amounts on Kodiak Island. These explosions generated substantial pumiceous pyroclastic, block, and ash flows that destroyed seismic and CGPS stations on the west and north flanks of the volcano [see figure 2 on original text]. Destruction of these seismometers compromised AVO's ability to assign reliable hypocentral depths to earthquakes.\r\n   \"Data from the remaining CGPS stations indicated that the volcano reversed its long inflationary trend (during which accumulating magma caused a swelling of the volcano's surface) and began a sharp deflation that continued until 10 February [see figure 3 in original text]. Modeling suggests the locus of deflation, which results from the removal of magma, was much deeper (~10 kilometers) than the precursory signal. On 29 January, the seismic network began to detect numerous block and ash flows - generated by small failures of the growing lava dome - cascading down the volcanos northern flanks [see figure 2 in original text].\r\n   \"Augustine then entered an effusive phase, which lasted through late March. From 2 February through 6 March, block and ash flow signals continued to dominate the seismic record. Geodetic data showed inflation from 10 February until 1 March, when the volcano again reversed and entered an 11-day period of deflation [see figure 3 in original text]. On 7 March, seismic activity again shifted to small, mostly identical repetitious earthquakes. These events increased in rate and size, forming a continuous signal early on 8 March that lasted until 14 March. They then began a slow decline and disappeared by 16 March. Lava extrusion at the summit increased markedly in association with these repetitive earthquakes, and two blocky lava flows moved down the north and northeastern flanks [see figures 1 and 2 in original text]. Observations indicate that the effusion of lava stopped in late March. The volcano entered a final period of inflation between 12 and 31 March. The estimated volume of effusively erupted material is currently 30 million cubic meters.\"\r\n\r\nMcGimsey and others (2011) report that throughout 2007, continued cooling from the 2005-2006 eruption, steam plumes, and anomalous seismicity were observed at Augustine.","StartYear":2005,"StartMonth":12,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2006,"EndMonth":3,"EndDay":31,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":596,"Name":"Shishaldin 2005/12","Description":"   From McGimsey and others (2007): \"Following more than a year of relative quiescence, on December 22, 2005, a pilot reported a steam plume rising 3,000 ft above the summit of Shishaldin.  The FAA issued an Urgent Pilot Report.  Commensurate with this report, a few small explosions were recorded on the pressure sensor located on the north flank.  AVO seismologists also noted that the amplitudes of seismic events had increased since about mid-November.  Because no ash apparently was released and the activity did not continue, AVO did not issue a formal information release nor increase the level of concern color code.\"","StartYear":2005,"StartMonth":12,"StartDay":22,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2005,"EndMonth":12,"EndDay":22,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":682,"Name":"Makushin 2006","Description":"From Neal and others (2011): \"On June 27, a USCG officer made a report to NOAA about a persistent area of discolored seawater in Unalaska Bay, about 3 km (1.9 mi) north of Dutch Harbor and in-line with Wide Bay cone and Table Top volcano, two satellite vents that are part of the larger Makushin volcanic field (McConnell and others, 1998). The officer stated that he had noticed this discoloration for approximately 2 years. NOAA forwarded the report and photographs via email to AVO on July 2.\r\n   \"AVO considered three possibilities for the discoloration: (1) ship discharge, (2) hydrothermal venting from a submarine volcanic cone, and (3) groundwater discharge or venting through the seafloor. A transient ship discharge was quickly ruled out, due to the phenomenon’s consistent presence and location. Discriminating between a volcanic or groundwater explanation for the discoloration is difficult without further investigation. Unalaska Bay is a normal location for seismic activity, and a quick examination of AVO’s seismic data for the area revealed nothing beyond background. On July 11, the NOAA ship Oscar Dyson conducted a conductivity, temperature, and depth (CDT) study near the site, and on July 24, the NOAA ship Fairweather conducted another CDT study and bathymetric mapping. The Oscar Dyson’s CTD study detected nothing unusual but the study was done too far from the apparent source to rule out a possible hydrothermal plume. The Fairweather’s survey showed seafloor mounds in the vicinity, possibly emitting plumes, but not directly under the anomaly. Conductivity and temperature measurements did not support a volcanic source. Further data collection and analysis in August by NOAA showed numerous sites of probable bubble streams coming out on the seafloor (seen in 2007 imagery). Another NOAA ship reported similar discolored water in a different, but nearby location in July 2008. At this time, we conclude that the multiple locations of discolored water at the surface and at the seafloor point to likely groundwater discharge, possibly through a fault system, rather than a submarine volcanic plume.\"","StartYear":2006,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":1,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":607,"Name":"Martin 2006/1","Description":"   From Neal and others (2009): \"On January 10, 2006, AVO raised the Level of Concern from GREEN to YELLOW after a sharp increase in earthquake activity beneath Mount Martin that had begun on January 8 (Dixon and others, 2007). Roughly 300 earthquakes were located in just over 2 days [see fig. 38 in original text], a significant increase over the long-term average rate of less than one event per day since the seismic network was installed in 1996. Satellite data did not indicate any obvious changes at the surface.\r\n   \"Elevated seismicity continued for about 2 weeks after which the rate of shallow volcano-tectonic earthquakes decreased to levels considered background for Mount Martin. On January 27, AVO downgraded the Level of Concern to GREEN. Throughout this seismic swarm, no surface manifestations of the increase in seismicity were noted in satellite imagery or by passing pilots. The cause of this swarm remains uncertain (John Power, USGS, oral commun., 2007).\"","StartYear":2006,"StartMonth":1,"StartDay":8,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2006,"EndMonth":1,"EndDay":22,"EndTime":null,"EndQualifier":2,"EndQualifierUnit":"Days","Volcano":"Martin","ParentVolcano":"Martin","VolcanoID":"ak189","ParentVolcanoID":"ak189"},{"ID":608,"Name":"Korovin 2006/1","Description":"From Neal and others (2009): \"Beginning on January 16, a brief (minutes-long) increase over this background level was noted. Additional bursts of tremor-like signals occurred on January 17-18, 21, and February 21-22, prompting AVO to raise the Level of Concern Color Code to YELLOW. Satellite imagery of the volcano showed nothing unusual, although clouds frequently obscured the region. AVO did not receive reports of activity from residents of Atka Village, despite periods of clear weather in late February.\r\nSeismicity stabilized and then decreased in early March, and AVO downgraded the Level of Concern Color Code to GREEN on March 8. Clear satellite looks and overflights by commercial pilots indicated no significant surface changes in the vicinity of Korovin. In the spring, there were several week-long outages where fewer than the minimum number of stations required to locate earthquakes were operational.\r\n   \"The number of earthquakes in the vicinity of Korovin began to increase again in July. Episodes of volcanic tremor were recorded again in September and October, increasing in number, strength, and duration into the fall. White plumes of water vapor reaching several hundred meters above the volcano were photographed from Atka on October 29 [see fig. 44 in original text], about coincident in time with a strong tremor burst about 5 minutes in duration captured on the Korovin network. The shallow lake in the main Korovin crater, present on September 12 according to satellite data, had disappeared by October 19, and remained absent through the end of the year. On November 5, the strongest earthquake swarm ever recorded by the AVO seismic network occurred. AVO decided to upgrade the level of concern for Korovin, based on this sustained increase in seismic activity and visual confirmation of increased fumarolic activity and disappearance of the lake. Utilizing the new warning scheme adopted by the United States Volcano Observatories in October, AVO declared Aviation Color Code YELLOW and Volcanic Activity Alert Level ADVISORY for Korovin on November 6.\r\n   \"Seismicity at Korovin remained above background through the year's end. Periodic strong, short-duration (tens of seconds to several minutes) signals recorded on the entire network may have been phreatic explosions or sudden hydrothermal boiling events. Similarly, several-minute-long, low-frequency tremor bursts at rates of several per hour occurred intermittently. ASTER satellite images from November 18 indicated an exposure of dark-gray ash on the eastern flank of Korovin's main crater [see fig. 45 in original text]; this ash was not present in a similarly clear image from November 21. Still, it is not known exactly when and by what process ash was emitted from Korovin; it also is possible that the ash visible in satellite imagery represents remobilization of older ash high on the cone, as may have been photographed during fieldwork in 2004 [see figs. 46 and 47 in original text]. Thermal bands in ASTER imagery showed warm areas in the Korovin crater, not a surprise given the known, ongoing fumarolic activity within the crater [see fig. 46 in original text].\r\n   \"In late November, AVO learned that the Korovin volcano area had undergone significant deformation during the second half of the year. InSAR results comparing data from July and October 2006 for Korovin indicated a very prominent, circular pattern of uplift of as much as 5 cm (2 in) centered about 5.5 km (3.4 mi) southwest of Korovin (see fig. 48 in original text; Z. Lu and P. Cervelli, USGS, written commun., 2006). This location generally is consistent with locations of earthquake swarms beginning in the summer. Two possible explanations for this uplift were considered: (1) a pressurizing and inflating hydrothermal system, plausible given the robust, disseminated hot springs around Korovin and neighboring Kliuchef volcanoes (Motyka and others, 1993) or (2) a rising magmatic intrusion and related deformation.\r\n   \"Residents of Atka continued to photograph particularly large, at times 'puffing' white-vapor plumes emanating from Korovin on December 11, 21, and 24 [see figs. 49 and 50 in original text]. At least one of these reports suggested the possibility of ash within the plume; the observer further clarified that he saw ash falling below the cloud after it attained some altitude. Ash on the ground was not verified. Satellite data did not detect any rise in ground temperature nor any ash in the atmosphere or on the ground through the end of 2006.\r\n   \"AVO tracked activity at Korovin using seismic and satellite data. Several times during the year, AVO staff contacted Atka residents by telephone or email to gather additional observations or clarify AVO reports. In February, AVO asked Peninsula Airways (Pen Air) pilots flying into Atka to pass along any pertinent observations. On February 22, Pen Air reported no sign of ash or anything unusual at the volcano.\"\r\n\r\nFrom McGimsey and others (2011): Korovin Volcano on Atka Island in the west-central Aleutians began 2007 in Aviation Color Code YELLOW and Volcano Alert Level ADVISORY following an upswing in activity during 2006 (Neal and others, 2008). A relatively high level of background seismicity has been prevalent since the AVO network was installed in 2004, and a higher level of seismicity that began in 2006 continued into the first half of 2007 [see figs. 45 and 46 in original text].\r\n   \"Reports of steam clouds on December 24, 2006, were followed on January 11, 2007, by a M3.5 earthquake at Korovin, which is considered quite large for volcano-generated seismicity. A swarm of likely associated events were recorded during the week; however, a M8.2 earthquake in the Kurile Islands on January 12 (AKST) also may have triggered seismicity at Korovin.\r\n   \"On January 23, a series of tremor bursts were recorded, and on January 24, AVO received photographs from an Atka Village resident of a steam column rising from Korovin's active crater [see fig. 47 in original text]. The observer reported similar steam columns rose up to about 1,000 ft (about 300 m) above the volcano every 15 to 80 minutes. Satellite images from the previous week indicated that the intermittent lake in Korovin's active crater was not present. Previously, in late September or early October 2006, the lake disappeared following a strong episode of steam emission. The lake had not re-appeared as of mid-January 2007.\r\n   \"The next report of activity at Korovin came on the afternoon of February 14 when NWS contacted AVO to pass on a PIREP from a U.S. Coast Guard C-130 of a steam plume extending 5,000-8,000 ft (about 1,500-2,400 m) over Korovin. A SIGMET was not issued.\r\n   \"A couple of weeks later, Atka Village residents Lynn and Kerry Moore sent photographs to AVO taken on March 3 of an ash deposit on the west flank of Korovin [see fig. 48 in original text]. Prior to taking the photographs, the Moores observed steam rising from the active, south summit vent. No anomalous activity was noted in AVO satellite reports for that day; however, a flurry of low frequency seismicity occurred that morning, comparable to seismicity of the last few months. Phreatic activity at Korovin produced similar ash deposits in 2004 and 2006 (Neal and others, 2008).\r\n   \"Episodes of tremor occurred over several days in May, June, and August, and a thermal anomaly was detected in satellite images in early August. Steam plumes were observed by residents in Atka Village in late July [see fig. 49 in original text]. The satellite-based Ozone Monitoring Instrument (OMI) detected a small SO2 cloud located about 300 km (186 mi)north of Cleveland volcano on August 5, 2007, that likely originated at Korovin based on wind dispersal models. An aerial photograph taken that day shows a steam plume wafting from the crater (fig. 50). On August 19, a flurry of 33 detected seismic events located 4 km (2.5 mi) southeast of Kliuchef was detected [see figures 50 and 52 for location of Kliuchef, 6.5 km (4 mi) south of Korovin]. This was followed on August 20 by a small emission of SO2 from Korovin that was detected by OMI [see fig. 51 in original text].\r\n   \"Inflation beneath the northern part of Atka Island that began in June 2006 and totaled 9-10 cm (3.5-3.9 in.) of uplift, had begun to taper off in 2007 (Zhong Lu and Peter Cervelli, USGS, written commun., 2007). An InSar interferogram acquired July 1, 2007, shows a distinct but weakened anomaly still centered on the west flank of Kliuchef volcano [see figs. 52 and 53 in original text]. Seismicity over the same period appears to have tracked the uplift (P. Cervelli, USGS, written commun., 2007); compare the area of uplift with the located seismicity in figure 53.\r\n   \"The decreasing trends of seismicity and uplift prompted AVO to begin considering a status change for the volcano, which had been at Aviation Color Code YELLOW and Volcano Alert Level ADVISORY since November 6, 2006. On September 7, 2007, the Aviation Color Code/Volcano Alert Level was downgraded to GREEN/NORMAL. Although circuit problems plagued the Atka Island network on several occasions, activity at Korovin was uneventful for the remainder of 2007.\r\n   \"AVO tracked activity at Korovin using seismic and satellite data, and occasional pilot reports. Several times during the year, AVO staff contacted Atka residents by telephone or email to gather additional observations or clarify AVO reports.\"","StartYear":2006,"StartMonth":1,"StartDay":16,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2007,"EndMonth":9,"EndDay":null,"EndTime":null,"EndQualifier":2,"EndQualifierUnit":"Months","Volcano":"Korovin","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak171","ParentVolcanoID":"ak17"},{"ID":552,"Name":"Cleveland 2006/2","Description":"From Neal and others (2009): \"The first known explosive eruption [at Cleveland Volcano]  in 2006 occurred on February 6, and was detected in routine Advanced Very High Resolution Radiometer (AVHRR) satellite image analysis by anomaliesAVO staff. Satellite-derived temperatures indicated an initial cloud height of about 6-8 km (22,000-26,000 ft). The eruption appeared to be short lived and had ceased several hours before detection on satellite imagery, but AVO raised the Level of Concern Color Code to RED and NWS issued a SIGMET. The cloud was tracked for more than 400 km (250 mi) southeast of the volcano before it largely dissipated in satellite images. By day's end, with no further reports or images of ash production at Cleveland, AVO downgraded the Color Code to ORANGE. For the duration of condition RED, the FAA imposed a temporary flight restriction (TFR) from the surface to 50,000 ft within a 5 nautical mile radius of the volcano.\r\n   \"AVO downgraded Cleveland to Color Code YELLOW 5 days later on February 11. Cloud cover persisted during most of this interval, and AVO's information release on February 11 noted that undetected, low-level unrest could continue. No further indication of activity led AVO to further downgrade Cleveland to a Color Code of 'Not Assigned' on February 20. (AVO policy is that a volcano lacking seismic instrumentation cannot be known to be at background, and hence cannot be assigned a Color Code GREEN).\"\r\n\"On May 5, AVO reported a thermal anomaly and continuous plume of volcanic gas from Cleveland. The plume was visible over the course of 6 hours but traveled only 48 km (30 mi) southwest of the volcano and appeared to be at a relatively low altitude and devoid of ash. Cleveland remained 'Not Assigned.'\r\n   \"On May 23, an astronaut aboard the International Space Station (ISS) contacted ground control with a report of an eruption from a volcano in the Aleutians. Subsequent communication with AVO, including receipt of a photograph [see fig. 41 in original text, and \u003ca href=\"http://www.avo.alaska.edu/image.php?id=10064\"\u003ehttp://www.avo.alaska.edu/image.php?id=10064\u003c/a\u003e online] and a telephone call from the ISS, confirmed Cleveland as the source. The plume was ash rich and by the time it was detected in AVHRR imagery, it was a detached ash cloud about 130 km (80 mi) southwest of the volcano. Satellite cloud-temperature data indicated a cloud top of about 6,700 m (22,000 ft) ASL. AVO raised the Level of Concern Color Code for Cleveland to YELLOW, and subsequently downgraded to 'Not Assigned' on May 26 after no further activity was detected.\r\n\"On August 24, AVO received notice from NWS that a ship had reported an ash eruption from Cleveland volcano. Days later, AVO received video footage from the crew of this fishing vessel showing a definite ash plume reaching about 3 km (~10,000 ft) ASL [see fig. 42 in original text]. Importantly, neither a broadband regional network seismic station in Nikolski [see fig. 1 in original text; M. West, UAFGI, written commun., 2006) nor any time-correlative satellite imagery showed evidence of this eruption. On September 7, after reviewing video footage of the August 24 event and noting an intermittently present thermal anomaly at the volcano, AVO raised the Level of Concern Color Code to YELLOW.\r\n   \"AVO was alerted by NWS of another Cleveland eruption on October 28 after a pilot report to the Anchorage Air Traffic Control Center. The pilot of a jetliner indicated an initial cloud over the volcano reaching their flight level of 36,000 ft (11,000 m) ASL, and a drifting cloud moving east-northeast at a lower level of 30,000 ft (9,100 m) ASL. Satellite-derived cloud top temperature estimates placed the plume much lower. Utilizing the new warning scheme adopted by United States Volcano Observatories in October, AVO declared Aviation Color Code ORANGE and Volcanic Activity Alert Level WATCH for Cleveland about 2 hours after receipt of the pilot report, and reverted to YELLOW/ADVISORY on October 30 after no indications of further activity. On clear days under optimal satellite viewing conditions, a weak thermal anomaly was detected in the vicinity of the summit crater at Cleveland into November [see fig. 43 in original text].\r\n\"Ash explosions likely occurred more often at Cleveland than were detected in either satellite imagery or by pilots or other observers. An infrasonic signal received at the Geophyiscal Institute in Fairbanks on November 6 may have been produced by an explosion at Cleveland (or a nearby volcano); however, with no corroborating evidence, AVO took no action (S.R. McNutt, UAFGI, written commun., 2006).\"","StartYear":2006,"StartMonth":2,"StartDay":6,"StartTime":"15:00:00","StartQualifier":15,"StartQualifierUnit":"Minutes","EndYear":2006,"EndMonth":11,"EndDay":20,"EndTime":"17:00:00","EndQualifier":2,"EndQualifierUnit":"Hours","Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":569,"Name":"Veniaminof 2006/3","Description":"   From the Smithsonian Institution (2006, v. 31, n. 3): \"On the morning of 3 March 2006 ash again rose a few hundred meters above the intracaldera cone, drifted E, and dissipated rapidly. Ashfall was expected to be minor and confined to the summit caldera. Seismicity was again low and did not indicate that a significantly larger eruption was imminent. Over the week of 5-10 March, seismicity was low but slightly above background.\r\n   \"On the morning of 10 March, AVO received a report from a pilot of low-level ash emission from the intracaldera cone. Clear web-camera views on 9 March showed small diffuse plumes of ash extending a short distance from the intracaldera cone. The Anchorage Volcanic Ash Advisory Center (VAAC) reported a steam/ash plume noted on web-cam and satellite on 13 March 2006 at 0500Z (12 March 2006 at 2000 hours local), moving NNW at 9.2 km/hr and falling to the land surface. Web-cam images on 22 March showed a very diffuse steam-and-ash plume that was confined to the summit caldera, and on 24 March showed a steam-and-ash plume drifting from the summit cone at a height of less than 2.3 km. This level of activity was similar to that on 23 March, but higher than activity on 21 and 22 March, when a very diffuse steam-and-ash plume was confined to the summit caldera.\r\n   \"The flow of seismic data from Veniaminof stopped on the evening of 21 March 2006, and the problem was expected to continue until AVO staff could visit the site to repair the problem. Absent seismic data, the volcano could potentially still be monitored in other ways such as using web-camera and satellite images. Imagery was obscured by cloudy weather after 21 March. On 26 March 2006, a pilot reported a small ash plume rising above the volcano. Low-altitude ash emissions from Veniaminof were visible during 31 March to 7 April. On 6 April, a pilot reported an ash plume at a height of 3 km. AVO stated in its weekly report of 14 April 2006 that the seismicity at Veniaminof remained low but above background. Internet camera and satellite views had been obscured by cloudy weather, and AVO lacked new information about ash clouds or activity.\"\r\n   Continued activity was summarized by the Smithsonian Institution (2006, v. 31, n. 8): \"Intermittent, very small-volume steam and ash bursts from the intra-caldera cone have been typical of this volcano intermittently over the past few years, and this pattern continued. The previous report mentions several minor bursts of ash, particularly on 13 June 2006 and 7 September, and minor white plumes through mid-September. This report discusses the interval 8 April through 15 September. Seismicity during this interval was nearly always low, although it often rose above background.\r\n   \"Clouds obstructed visibility during 7-14 April. For the duration of April and June, activity remained low with few steam plumes containing minor amounts of ash. On 30 May a weak daytime thermal anomaly was recorded, possibly due to solar heating inside the dark intra-caldera cone. Intermittent clear weather on the week ending 9 June indicated weak steam plumes.\r\n   \"On 13 June an ash emission rose to a height estimated at ~ 600 m above the summit area, as reported by a passing aircraft. Transient plumes were seen on satellite imagery during the week ending 21 July.\r\n   \"During the week ending 28 July, an AVO field party flew over the summit and observed typical steaming from the intra-caldera cone with no signs of recent ash emissions. Satellite and web camera views during occasional clear periods showed no other signs of activity. Occasional satellite views during clear weather failed to disclose new ash emissions during 28 July through 15 September.\r\n   \"AVO noted a slight increase in seismicity starting 2 August but in the subsequent weeks it again returned to low levels. Available satellite and camera views continued to reveal occasional small white plumes through 15 September.\"\r\n  Steam plumes without ash emission continue to be observed at Veniaminof, as of this writing (March 21, 2007).  \r\n\r\nMcGimsey and others (2011) report that by January 2007, the intracaldera cinder and spatter cone was producing only minor, diffuse steam plumes that rose at most a few hundred meters above the vent. * * * Foloowing several weeks of cloudy weather, clear web camera views on the morning of February 16, 2007, revealed vigorous steaming from the intracaldera cone [see fig. 22 in original text]. Clouds and a short camera outage prevented observations for several days, and then on the morning of February 20, a clear view showed little to no steaming from the cone. Minor steaming was visible through February 24 when weather permitted, and by February 25, no signs of steam emissions were apparent in web camera images. Over the next couple of months, intermittent clear views of the volcano in either web camera images or in satellite images showed that occasionally minor steam plumes were issuing from the intracaldera cone. Seismicity had decreased to background levels several months prior, and the last ash-laden plume visible in web camera images was on November 2, 2006. The last thermal anomaly visible in satellite images was on July 5, 2006. Ground observers and pilots reported no unsual activity in recent months, and therefore on April 26, 2007, AVO lowered the Aviation Color Code/Volcano Alert Level to GREEN/NORMAL. Based on historic patterns of eruptive behavior, AVO anticipated continued steaming from the cone. Indeed, Veniaminof continued to steam intermittently throughout 2007.\"\r\n\r\nFor additional photographs and observations of this event, please see: Neal, C.A., McGimsey, R.G., Dixon, J.P., Manevich, Alexander, and Rybin, Alexander, 2009, 2006 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: Summary of events and response of the Alaska Volcano Observatory: U.S. Geological Survey Scientific Investigations Report 2008-5214, 102 p., available at \u003ca href=\"http://pubs.usgs.gov/sir/2008/5214/\"\u003ehttp://pubs.usgs.gov/sir/2008/5214/\u003c/a\u003e.","StartYear":2006,"StartMonth":3,"StartDay":3,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2006,"EndMonth":11,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Veniaminof","ParentVolcano":"Veniaminof","VolcanoID":"ak301","ParentVolcanoID":"ak301"},{"ID":609,"Name":"Kasatochi 2006/6","Description":"From Neal and others (2009): \"Bubbling from the Kasatochi crater lake was first reported in the summer of 2005 (McGimsey and others, 2007) and continued into 2006. U.S. Fish and Wildlife Service (USFWS) scientist Brie Drummond, who has spent several summers on the island and was the principal observer of the 2005 activity, visited the south caldera rim on the morning of June 2, 2006. The day was overcast but calm and the lake surface was 'like glass.' Drummond noted a disturbance on the water surface on the west side of the lake, easily visible with the naked eye and very similar to what she had seen in 2005. The disturbance was in the same sector of the lake as in 2005 although perhaps smaller in area [see figs. 52 and 53 in original text].\r\n   \"She described it as similar to 'rain falling onto a smooth lake surface.' However, in the absence of rain, it probably was a gentle effervescence. The spot on the lake surface was too far from the sheer rock walls to be explained by falling debris disturbing the water, and no birds or other biological activity were observed on the lake to account for the phenomenon.\r\n   \"Drummond described the bubbling as patchy with variable concentrations of bubbles, some occurring almost in a straight line. The bubbling was rapid and did not appear to change markedly over the course of 30 minutes of observation. As in 2005, Drummond noted no steam, no smell or odd discoloration of the water; gulls floated on the far side of the lake. On a windy day a week prior (May 26, 2006), Drummond’s field party did not see the bubbling, but it may well have been masked by the strong surface wave action due to high winds. Based on Drummond’s sketch, the bubbling zone in 2006 was about 100-200 m (~330-660 ft) across [see figs. 52 and 53 in original text].\r\n   \"Sampling of lake water was logistically impossible due to difficult, hazardous access, and we have no direct analyses of water or the gas phase to investigate the source of the bubbling. USGS chemist Bill Evans (written commun., 2007) prefers magmatic or hydrothermal processes to explain the bubbling observed in this young volcanic crater lake based on the apparent high flux, the scarcity of vegetation on the crater walls to provide a source for organic decomposition, and the very localized nature of the bubbling areas. The youthfulness of this crater would be consistent with ongoing fumarolic activity that now is submerged. Trains of bubbles rising vertically from subaqueous-gas vents are common at similar volcanic lake settings such as at Mount Spurr and Gas Rocks. The apparent intermittent nature of the bubbling simply may reflect a strong dependence on meteorological conditions favorable to viewing or some seasonal variability depending on water depth. Another possibility put forth by Evans proposes degassing of a volatile-enrich, deeper water layer during disturbance of a salinity-controlled stratified water column.\"","StartYear":2006,"StartMonth":6,"StartDay":2,"StartTime":null,"StartQualifier":7,"StartQualifierUnit":"Days","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kasatochi","ParentVolcano":"Kasatochi","VolcanoID":"ak146","ParentVolcanoID":"ak146"},{"ID":555,"Name":"Fourpeaked 2006/9","Description":"From Neal and others (2009): \"As fall arrived in Alaska, a phreatic eruption from a volcano not considered active in the Holocene surprised AVO and residents of south-central Alaska. Late on Sunday, September 17, AVO received several citizen telephone reports of a dark plume, fed by what appeared to be two sources, rising from the area near Cape Douglas in lower Cook Inlet. Satellite analysis indicated the source of the plumes to be roughly between closely spaced Douglas and Fourpeaked volcanoes. he drifting cloud produced by these rising plumes persisted throughout the night, reaching a minimum altitude of 20,000 ft (6,100 m based on radar data; Dave Schneider, USGS, written commun., 2006), but drifting only 20 km (12 mi) downwind in an unusually calm and clear atmosphere over south-central Alaska. \r\n   The next day, AVO issued an information release mentioning Douglas and Fourpeaked volcanoes, but stated that the exact nature and source of the plumes remained unclear. Neither volcano was monitored seismically, and data from the nearest stations at Katmai and Augustine initially showed nothing dramatic. Deteriorating weather conditions precluded visual observations, but an overflight was scheduled for the first clear window. On the afternoon of September 18, NWS relayed a pilot report of a strong sulfur odor 300 km (190 mi) northwest of Fourpeaked. This was an area likely to be impacted by drift of the September 17 cloud according to PUFF, a volcanic ash tracking model used by AVO (Searcy and others, 1998). Pilots in the Lake Iliamna area on the morning of September 18 also reported a strong sulfur odor, a locality also consistent with likely cloud drift on the 17th.\r\n    On September 20, AVO received NWS radar and other satellite data indicating particulate and sulfur-bearing properties in the cloud of September 17, confirming a volcanic source for the event. Based on this, AVO announced Level of Concern Color Code YELLOW for both Douglas and Fourpeaked volcanoes because the source was still uncertain. NEXRAD Doppler radar images from King Salmon showed a particulate cloud in the atmosphere from at least 12:00 p.m. to 9:45 p.m. ADT on September 17. The cloud appeared most energetic (dense) in the first 2 hours (Dave Schneider, USGS written commun., 2006). The bulk of the cloud remained over the point of origin for much of this time, reflecting very calm atmospheric conditions on that day. In addition, Ozone Monitoring Equipment onboard National Aeronautics and Space Administration's (NASA) Aura satellite indicated a pod of SO2 gas in the general vicinity of the eruption plume at 3:00 p.m. ADT. Subsequently, AVO received reports of a very fine-ash dusting at Nonvianuk Lake outlet (110 km or 70 mi west northwest of Fourpeaked) and near Homer (150 km or 90 mi northeast of Fourpeaked). The Nonvianuk report stated, 'We have a heavy sulfuric smell in the air and ash filling the air. The wind here is blowing from the ESE' No samples were retrievable from either location for analysis, but the Nonvianuk report is consistent with PUFF trajectories for a cloud reaching about 20,000 ft (6,100 m) on the afternoon of September 17. Interestingly, multi-spectral satellite images showed no ash signature in the plume on September 17, but AVO analysts did note a thermal anomaly in the vicinity of Fourpeaked (J. Dehn, University of Alaska Fairbanks Geophysical Institute (UAFGI), written commun., 2006). Following the initial event on September 17th, no further particulate clouds were imaged by radar or other means. \r\n   An AVO overflight on September 20 confirmed Fourpeaked as the source of volcanic activity. Despite cloud cover of the actual summit, observers in a fixed-wing aircraft circled several distinct vapor clouds rising through the cloud deck above Fourpeaked. Visible patches of discolored snow and ice, especially north and west of the Fourpeaked summit, suggested ash fallout. An AVO helicopter crew later on the same day photographed a lobate, dark debris-flow tongue that had emerged from glacial ice about 3,000 ft (900 m) below the cloud-covered Fourpeaked summit; patchy areas of grey ash on the glacial ice around the summit and to the northeast also were noted. Clouds and fuel limitations prevented any further exploration of the area. \r\n   Aerial inspection of the Fourpeaked area on September 23 finally revealed the source of the September 17 plume and continuing fumarolic emissions. Water vapor and volcanic gas billowed from a dramatic, linear series of pits or vents extending about 1,250 m (4,100 ft) across the heavily crevassed and disrupted glacial-ice cover on the north side of the summit region. Multiple sources of vapor from these vents explain the apparent double plume seen in the photograph of September 17. A light dusting of dark material surrounded some of the open pits and several elongate dark stripes leading down slope from at least one vent probably represented remobilized fragmental ejecta mixed with melted ice and snow (or plume condensate). A subtle series of snow-mantled rills leading down slope in the same area indicated several episodes of surface debris or water flow. Stormy weather between September 17-23, produced new snowfall indicating that the ejecta collars and small debris flows observed on September 23 had occurred after the initial event.\r\n   AVO scientists visited the area by helicopter on September 24 and 25. The vent area consisted of as many as nine discrete craters or pits, and between three and five were venting steam and volcanic gas at any one time. The vents occurred along a line trending north from the summit basin, inferred to be a glacial cirque, obliquely down-slope across a northwest trending, ice-covered ridge. The bottoms of non-steaming pits were covered with blocks of debris-mantled ice. The upper craters within the Fourpeaked summit cirque had coalesced creating a heavily disrupted ice zone. Most craters were surrounded by fine (?) debris collars that did not extend very far from their rims; there was no evidence of additional, significant ash emission since September 17. FLIR imaging of the pits indicated elevated temperatures as high as 75C (167F); however, these values are minimums due to steam obscuration. A strong sulfur odor was noted downwind of the vents as far as 50 km (30 mi).\r\n   The glacial outburst associated with the September 17 event originated from beneath a chaotic ice jumble on the unnamed north-trending glacier at an elevation of about 5,000 ft. This flood apparently scoured a steep-walled canyon more than 100 m (330 ft) deep in places. Blocks of ice up to 5 m (16 ft) or more across had been rafted in a mixture of water and fine-grained to cobble-boulder sized, heterolithologic volcanic debris at least 6 km (4 mi) down slope, where material spilled off the front of the glacier ice and traveled an unknown distance into the Douglas River drainage. Levees of ice, sediment, and rock clasts as much as 10-15 m (33-50 ft) high marked the margins of the deposit. Where traced into the Douglas River drainage about 3-4 km (2-2.5 mi) from the glacier snout, the deposit was thin (about 2 cm or 0.8 in) and fine grained with a maximum clast size of about 1 cm (0.4 in). The field crew flew the length of the Douglas River to Cook Inlet and noted evidence of a flooding event represented by recently emplaced fine-grained gray sediment on beaches and river banks. On the day of observation, there was no evidence of continuing discharge of meltwater or debris down this newly carved drainage system. \r\n   AVO scientists collected samples of the fine, gray ash-fall deposit from the September 17 event. Deposits were most impressive west of the vent area where they were estimated to be 1-2 mm (less than 0.1 in) thick. Other flanks of the volcano received a mere dusting (\u003c1 mm); based on these few observations and the outlier reports of extremely light ash fall noted at two distant locations, the fall deposit likely represents well under 1 million cubic m of material. Preliminary petrographic analyses indicate the tephra consists of hydrothermally altered volcanic rock and crystal fragments, notably pyrite, and other accessory minerals (J. Larsen, UAFGI, written commun., 2006).\r\n   AVO geologists in the field on September 24-25 also reported loud rumbling sounds associated with sudden bursts of water from the ice-bedrock contact at an elevation of approximately 4,000 ft on the northwest flank of Fourpeaked; these flows lasted several seconds and then disappeared. An overflight of the cliff below these outbursts did not reveal anything unusual, and any relationship between these periodic outbursts of water with the events of September 17 is uncertain. \r\n   AVO geologists made further ground-based observations of the deposits and features related to this unrest in mid-October. Close helicopter passes of the vent area on October 14 revealed that several of the original craters had coalesced and the rims of the sheer-walled pits had retreated, enlarging most by perhaps tens of meters. The pit rims were blanketed by fresh snow indicating no additional ash emission of significance since the explosion on September 17. However, intermittent, vigorous fumarolic activity capable of entraining a small amount of locally derived material may have continued and gone undetected between overflights. Field observers saw no sign of large ballistics littering the surface, so any ongoing phreatic emissions were not very energetic. Yellow-stained (most likely sulfur) snow surrounded the upper crater. \r\n   Deposits related to the outburst flood into the Douglas River were examined more closely and consisted of gray, soggy, water-saturated, sulfur-smelling silty material containing cobble-sized clasts of dense, altered, volcanic rock and pyrite (and possibly marcasite). Preliminary results from x-ray diffraction and x-ray fluorescence analyses of a non-pyritic material indicate that the volcanic rock composition primarily is dacite, and that the fine fraction also contains minor gypsum and minor smectite (K. Bull, ADGGS, written commun., 2007). Interestingly, near the snout of the glacier impacted by this outburst flood, AVO geologists noted multiple layers of similar, sulfurous, heterolithologic material exposed in the ice stratigraphy, and postulated that these may represent prior (possibly historical in age) debris-flow events captured in the ice. \r\n   Eight airborne gas measurements were obtained between September 23 and November 18, 2006. Sulfur dioxide output was steady and high for a non-erupting volcano ranging between 820-2,940 ton/d (Doukas and McGee, 2007). For the same period, CO2 flux was between 340-834 ton/d. In contrast to Augustine Volcano (McGee and others, 2006), H2S output from Fourpeaked remained quite high, between 70-140 ton/d, likely reflecting the dominance of a wet hydrothermal system at this ice-clad volcano. In addition to these onsite, airborne measurements, Ozone Mapping Instrument (OMI) sensors occasionally detected SO2 clouds in the area. Beginning in October, low sun angles prevented good results and AVO stopped receiving reports from the OMI satellite team at the University of Maryland (D. Schneider, USGS, oral commun., 2006).\r\n   Seismic activity as recorded on the three new stations installed following the event on September 17 remained relatively low through the end of the year, typically with only a few volcanic earthquakes captured on most days. These three stations augmented coverage by regional seismic station CCDN about 17 km (~11 mi) northeast of Fourpeaked. On October 3, a swarm consisting of tens to hundreds of very small, non-locatable earthquakes occurred in the vicinity of Fourpeaked. A second swarm on November 5-6 occurred within the new Fourpeaked subnet and 75 events were located. Seismicity remained elevated with occasional small swarms of activity (10 located events per day or less) through the end of the year. Small explosion signals also began to be recorded in the spring; these signals may have reflected transient increases in fumarolic emission.\r\n   Further analysis of Katmai area seismic stations during the time period of the eruption cloud and opening of vents in the ice revealed a small swarm of earthquakes between 11:48 a.m. and 3:50 p.m. ADT on September 17 (M. West, UAFGI, oral commun., 2006) coincident in time with the onset and development of the plume seen in radar images. The University of Alaska Fairbanks infrasound array also detected a signal at about 20:50 UTC on September 17, likely an explosion source, at a time and location consistent with the plume sighting (S.R. McNutt, UAFGI, oral commun., 2006). \r\n   AVO concluded that the unrest at Fourpeaked volcano most likely involved the presence of new magma at fairly shallow (less than a few kilometers) levels, accounting for the seismicity and degassing, and providing a heat and gas source for a phreatic explosion, vigorous phreatic emission of gas and fine particulates, and a glacial outburst of meltwater, glacial ice, and hydrothermally altered debris on September 17. \r\n   A shallow, degassing intrusion of fresh magma also would account for the ongoing gas emissions (K. McGee, USGS, oral commun., 2006). The lack of a seismic network at Fourpeaked precludes exact determination of the onset of seismicity that may have been associated with an intrusion. However, the swarm detected on the Katmai network on September 17 likely captured the most vigorous phase of the event, including the onset of phreatic eruption. \r\n   Through the remainder of 2006 and into 2007, a variably robust plume of vapor and volcanic gas discharged from the linear chain of pits in the ice. Overflights into mid-November documented minor changes in the pit morphologies, primarily related to coalescence and widening. No further ash emissions of significance were noted, although an increasingly visible coating of a yellow, likely sulfurous deposit stained snow and ice cover around the Fourpeaked summit.\" \r\n\r\nFor detailed observations and photographs of this event, pelase see: Neal, C.A., McGimsey, R.G., Dixon, J.P., Manevich, Alexander, and Rybin, Alexander, 2009, 2006 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: Summary of events and response of the Alaska Volcano Observatory: U.S. Geological Survey Scientific Investigations Report 2008-5214, 102 p., available at \u003ca href=\"http://pubs.usgs.gov/sir/2008/5214/\"\u003ehttp://pubs.usgs.gov/sir/2008/5214/\u003c/a\u003e .\r\n\r\nMcGimsey and others (2011) report that throughout the first half of 2007, seismicity, steaming, and gas emissions decreased at Fourpeaked following the 2006 eruption. McGimsey and others (2014) continue the chronology of this event: \"Steam and gas emissions were frequently observed in web camera images and during routine gas measurement flights through the first half of 2008, and were visible to an AVO field crew on Augustine Volcano in July 2008 (AVO internal log entries). Activity continued to decrease into, and through 2009.\r\n    \"Steam plumes were visible in the web camera on February 8, 2009, and during gas measurement flights on June 6, 2009, and November 2, 2009; during the November overflight, no gas was detected (M. Doukas, U.S. Geological Survey, written commun., 2012). As the phreatic activity diminished, the melt holes begam filling with snow and fumarolic activity was observed only from a single vent. \r\n   \"The seismic and infrasound networks, and the web cam, were serviced in the summer of 2008, and a year later, as the batteries drained, the instruments stopped recording data. On November 18, 2009, prompted by the network outage and inability to assess the level of seismic activity, AVO issued a Volcanic Activity Notice and an Information Release downgrading Fourpeaked from Aviation Color Code GREEN and Volcano Alert Level Normal to UNASSIGNED, thus removing it from the list of seismically monitored volcanoes.\"","StartYear":2006,"StartMonth":9,"StartDay":17,"StartTime":"12:00:00","StartQualifier":10,"StartQualifierUnit":"Minutes","EndYear":2006,"EndMonth":9,"EndDay":17,"EndTime":"21:45:00","EndQualifier":30,"EndQualifierUnit":"Minutes","Volcano":"Fourpeaked","ParentVolcano":"Fourpeaked","VolcanoID":"ak103","ParentVolcanoID":"ak103"},{"ID":642,"Name":"Akutan 2007/1","Description":"   From McGimsey and others (2011): Akutan is one of several Alaska volcanoes at which seismicity was triggered by the M8.2 earthquake generated in the Kurile Islands on January 13, 2007, 0423 UTC. Four of the seven largest triggered Akutan events, ranging in magnitude from 0.0 to 0.5 and depths from 0.86 to -2.17 km, were located (see fig. 36 in original text; John Power, AVO/USGS, written commun., 2010). The earthquake locations fall along the trend of intense seismicity and ground breakage that occurred in March 1996 at Akutan (Neal and others, 1997; Waythomas and others, 1998, fig. 10; Lu and others, 2005). The AVO Akutan seismic network was installed in the summer of 1996, and this was the first instance of observed triggered seismicity at Akutan; however, it was short-lived and did not result in any detectable surface disturbance.\r\n   \"In early October 2007, AVO remote sensors using GPS time series for Akutan detected signs of renewed inflation over the previous month of the west flank, the same area that inflated during the 1996 seismic crisis. A few days later, on October 8, the manager of the Trident seafood processing plant called to alert AVO of 'strong steaming' from a 'new' area in the Hot Springs Bay valley [see fig. 37 in original text]. Long-known thermal springs occur along the lower course of the stream draining the valley, and the photograph of figure 37 shows a steam column apparently rising from further up-valley of the springs area. This also is the area of maximum deflation following the 1996 seismic swarms. No unusual seismic activity was noted for the period of west-flank inflation or this steaming episode. This location for a steam plume was considered 'new' by local observers because the lower-valley thermal springs rarely emit a concentrated, vertically rising plume of steam and most reports of steaming arise from the prominent fumarole field located at the 1,500-ft-level of the eastern flank at the headwaters of Hot Springs Bay valley [see fig. 38 in original text].\"","StartYear":2007,"StartMonth":1,"StartDay":13,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2007,"EndMonth":10,"EndDay":null,"EndTime":null,"EndQualifier":1,"EndQualifierUnit":"Months","Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":632,"Name":"Wrangell 2007/2","Description":"   From McGimsey and others, 2011: \"On January 13, 2007, at 0423 UTC (1923 AKST January 12), a M8.2 earthquake in the Kurile Islands likely triggered seismicity at several Alaska volcanoes including Wrangell, Katmai, and possibly Korovin, as the low frequency, large magnitude wavetrain rolled through these areas (Stephanie Prejean, AVO/USGS, written commun., 2007). There were no reports of anomalous steaming at Wrangell immediately following this event; however, on February 7, a fairly large local earthquake was recorded on the Wrangell network (Katrina Jacobs, AVO/UAFGI, written commun., 2007), that was followed 2 weeks later by reports of steaming from the summit. The report came from staff at Wrangell-St. Elias National Park and Preserve in Copper Center, and was presented during a local newscast (KTUU 5 p.m. report, February 20, 2007). This was the first report of Wrangell steaming in several years. \r\n   \"Local residents reported more episodes of steaming in March [see figs. 4 and 5 in original text]. On the evening of March 25, a strong sulfur odor was reported by a resident living about 50 air miles north of the summit of Wrangell, who also stated that this occurrence was rare in his 15 years living in the area. Earlier in the day, several multi-station seismic events were recorded on the Wrangell network (Katrina Jacobs, AVO/UAFGI, written commun., 2007). A few months later local residents sent AVO photographs taken on June 20 of steaming from Wrangell and a deposit of ash extending from the west crater several thousand feet down the southwest flank [see fig. 6 in original text]. This ash was likely redistributed from the summit craters by strong winds. No anomalous seismic activity was observed.\"","StartYear":2007,"StartMonth":2,"StartDay":7,"StartTime":null,"StartQualifier":1,"StartQualifierUnit":"Months","EndYear":2007,"EndMonth":6,"EndDay":20,"EndTime":null,"EndQualifier":3,"EndQualifierUnit":"Minutes","Volcano":"Wrangell","ParentVolcano":"Wrangell","VolcanoID":"ak326","ParentVolcanoID":"ak326"},{"ID":590,"Name":"Cleveland 2007/6","Description":"    Although intermittent thermal anomalies were sporadically observed in satellite images by AVO throughout 2007, on June 12, steam emissions caused a plume that extended 200 km from the volcano, and pilots reported the height as up to 12,000 feet (3650 m).  Significant thermal anomalies were observed in satellite images on June 17 and 26, and AVO geoscientist interpret these as being suggestive of low-level eruptive activity.  Weaker thermal anomalies were observed on July 3, 5, and 12.  \r\n   On July 20, 2007, an intense thermal anomaly and associated steam/gas plume were observed at Cleveland in satellite images, prompting AVO to raise the aviation color code from YELLOW to ORANGE, and the volcano alert level to WATCH.  AVO later received photographs of the event, showing small bursts of ash rising a few thousand feet above the summit.  Persistent thermal anomalies were observed in satellite data for the following week.  During the first week in August, they were intermittently visible, and then occasionally visible.  Photographs taken on July 27 show fresh volcanic ejecta on Cleveland.\r\n   On Sunday, August 12, a pilot reported that Cleveland was not steaming and showed no signs of activity.  During the following two weeks, occasional thermal anomalies were observed in satellite imagery, despite the mostly cloudy conditions\r\n   On Thursday, September 6, 2007, AVO lowered the aviation color code to YELLOW, and the volcano alert level to ADVISORY, due to the decreased intensity of the thermal anomalies.\r\n   On October 12, AVO reported that retrospective analysis of seismic data indicated an explosion at Cleveland on October 3, 2007.  A thermal anomaly was detected on October 7.  \r\n   On November 20, AVO observed a weak thermal anomaly near the summit of Cleveland.\r\n   On January 17, 2008, a minor ash emission was detected in satellite data.  AVO estimates that the cloud height was likely less than 10,000 ft (3048 m).  A weak thermal anomaly was observed at the summit in several satellite images following the ash event.\r\n   A weak thermal anomaly was again detected in satellite imagery on January 30.  Although Cleveland was often obscured by clouds in early February, a break in clouds on the night of February 7 permitted a brief satellite view of a diffuse, low-level (5000 ft or less) ash plume that extended up to about 12 km southeast of the volcano.  On February 8, aircraft pilots reported seeing a plume from Cleveland up to 20,000 ft.  Satellite data from AVO showed a diffuse ash cloud extending northwest from the volcano.\r\n\r\nOn March 4, 2008, a pilor reported minor ash to 5,000 feet above sea level in the vicinity of Cleveland, and a weak thermal anomaly was observed the following day. Thermal anomalies continued throughout March and April, and a small, low-altitude (less than 15,000 feet) discrete ash cloud was observed in satellite images from May 7, 2008.\r\n\r\nOn Monday, July 21, 2008, fishing boats reported an eruption occurred at Cleveland at approximately 12:00 AKDT. AVO raised the color code/alert level to ORANGE and Watch. The eruption continued, with a persistent ash emission from 10,000 to 20,000 feet above sea level. Also on July 21, a strong thermal anomaly was observed in satellite images, perhaps indicative of a lava flow. By August 6, the thermal anomalies had decreased in intensity, indicating that hot flows erupted onto the upper west, south, and southeast flanks had slowed. At that time, the last ash plume observation (satellite imagery) was July 29, although visibility is often limited. AVO lowered the color code/alert level to YELLOW and Advisory on August 6. \r\nDue to increasing thermal anomalies, AVO again raised the level of concern color code and alert level ot ORANGE and Watch on August 10, 2008. A small ash plume to 25,000 feet was observed on August 12. Eruptive activity declined, and the color code/alert level was lowered to YELLOW and Advisory on August 25.\r\n   A thermal anomaly was last noted on September 4, 2008, and AVO lowered the color code/alert level to Unassigned/Unassigned on October 9, 2008.\r\n\r\nFrom McGimsey and others (2011): \"Cleveland began 2007 in Aviation Color Code YELLOW and Volcano Alert Level ADVISORY following intermittent eruptive activity throughout 2006 (Neal and others, 2008b). Discussions in weekly AVO staff meetings, during January and early February 2007, on downgrading Cleveland to Aviation Color Code GREEN were interrupted by the detection of new thermal anomalies [see table 5 in original text]. Satellite data from February revealed evidence of recent activity involving ejection of bombs and debris on the upper flanks and generation of water-rich flows that travelled halfway to the coast. No ash emissions or ash fall deposits were observed. This level of activity -accompanied by persistent thermal anomalies - occurred throughout the spring and early summer. On July 20, an intense thermal anomaly (fig. 40) was accompanied by a steam and gas plume visible in satellite images [see fig. 41 in original text], and mariners in the area reported low-level ash emissions [see fig. 42 in original text]. Several small SO2 plumes were detected in Ozone Monitoring Instrument (OMI) satellite data (Dave Schneider, AVO/USGS, written commun., 2010). The ash and SO2 emissions signaled an increase in eruptive activity prompting AVO to raise the Aviation Color Code and Volcano Alert Level to ORANGE/WARNING.\r\n   \"Over the next 3 weeks, thermal anomalies were observed when weather conditions allowed for clear views, but no steam or ash emissions were observed. A pilot got a close view of the summit crater on July 27 and reported evidence of recently emplaced debris including blocks rimming the crater and sulfur deposition [see fig. 43 in original text].\r\n   \"A new Web camera aimed at Cleveland was installed in Nikolski, 75 km (45 mi) to the east, on August 6, but poor weather frequently precluded imaging the volcano. During the last 2 weeks of August, thermal anomalies decreased in size and intensity. The Aviation Color Code and Volcano Alert Levels were downgraded to YELLOW/WATCH on September 6 in response to the apparent waning of eruptive activity. Thermal anomalies continued to be observed, but with lower temperatures and intensities [see fig. 44 in original text].\r\n   \"Retrospective analysis of seismic data from stations located on Umnak Island, and distant pressure sensors [see table 5 in original text], suggested that an explosion occurred at Cleveland on October 3, 2007. No other evidence of this activity was forthcoming. Thermal anomalies continued to be seen through mid-November, visible during the few non-cloudy satellite views. During late November and through December, no thermal anomalies or activity were reported, and Cleveland ended 2007 in Aviation Color Code/Volcano Alert Level YELLOW/ADVISORY.\r\n   \"As in 2006, AVO tracked and responded to Cleveland activity in 2007 by relying heavily on remote sensing of the volcano and rapid response to reports received from pilots or other sources. Automatic PUFF runs of hypothetical ash trajectories appeared on the PUFF Website.\"\r\nFrom Neal and others (2011): \"Cleveland volcano on remote Chuginadak Island in the central Aleutians continued to produce infrequent but sudden explosions of ash in 2008 with a brief period of more vigorous activity in late July. Cleveland is unmonitored by ground-based seismic instrumentation. A web camera 73 km (45 mi) east in the community of Nikolski on Umnak Island is often obscured by weather. In an area of frequent thick cloud cover, satellite remote sensing is limited in application to reliably detect thermal anomalies and ash clouds resulting from volcanic explosions.\r\n   \"Cleveland volcano began 2008 at Aviation Color Code YELLOW and Volcano Alert Level ADVISORY. Daily satellite monitoring detected an ash cloud drifting north from Cleveland in imagery on January 17; the cloud rose less than about 3 km (10,000 ft) ASL and it was visible in satellite imagery for 2 hours before dissipating. A weak thermal anomaly (TA) persisted in the summit area following this event, visible to analysts in rare, clear satellite images over the next few weeks. Another low-level (below about 1.5 km or 5,000 ft ASL) ash cloud was visible in a satellite image on February 8. Later that day, two pilot reports of volcanic ash from Cleveland reaching altitudes of 20,000 ft (6,100 m) ASL, confirmed on satellite imagery, prompted AVO to elevate the volcano to ORANGE/WATCH. With the exception of a weak, possible TA several days later, no further activity was detected and Cleveland was returned to YELLOW/ADVISORY status on February 12.\r\n   \"Minor, short-lived ash explosions continued through the winter and were caught by the twice-daily routine satellite monitoring by AVO analysts or pilots on February 16, February 22, February 29, and March 4. Weak Tas seen in satellite imagery often followed these ash bursts; Tas continued to be spotted into the spring. ASTER satellite data in mid-April indicated intermittent low level activity producing ejecta and flowage deposits of very limited extent [fig. 28; imageid 14231].\r\n   \"In late April and early May, the TA at Cleveland became more persistent. On May 7, an ash cloud was detected in satellite imagery and AVO received a report from the F/V Raven Bay of a dusting of ash north of the community of Nikolski. Satellite imagery detected impact craters in snow near the summit of the volcano, consistent with an explosive event. A weak TA was detected on June 8.\r\n   \"No further reports of activity were received until July 21 when fishing vessels reported an explosive eruption of Cleveland about 12 p.m. Several mariners documented activity with photographs and video [figs. 29; imageid 15336, 30; imageid 15097 and 31; imageid 15373]. The ash cloud was described as moving generally northwest from the volcano but the cloud was not visible in satellite imagery, perhaps due to thick regional cloud cover. AVO declared ORANGE/WATCH based on these reports. Subsequently, pilots reported the Cleveland ash plume to be between 15,000 and 17,000 ft ASL and moving southeast from Cleveland. An AVO scientist aloft over Okmok in a USCG C-130 also observed the Cleveland ash cloud - distinctly darker than the regional meteorological clouds - approaching from the west.\r\n   \"On July 22, satellite imagery showed a greater than 50 km (31 mi) long plume of gas and water vapor with some ash drifting east and southeast at an altitude of between 3 and 6 km (10,000 and 20,000 ft). A strong and persistent TA may have reflected the presence of a lava flow in the summit crater and along the upper steep portion of the volcano. A fairly continuous, weak ash plume continued at least through July 25. On July 27, satellite images showed a possible ash cloud drifting southeast with a cloud top of less than 6 km (20,000 ft). The strong TA near the summit of the volcano decreased in intensity during the first week of August and on August 6, AVO downgraded Cleveland to YELLOW/ADVISORY.\r\n   \"On August 11, AVO reinstated ORANGE/WATCH because of the persistent TA interpreted to reflect effusion of lava from the summit crater. An August 12 satellite image showed a small ash cloud rising to about 25,000 ft (7,600 m) ASL and drifting southwest about 60 mi (100 km) before dissipating. Despite an intermittent thermal anomaly, AVO detected no further ash emissions and downgraded the volcano to YELLOW/ADVISORY on August 25 and to UNASSIGNED on October 9. (Note: in prior year reports, AVO has used the term 'Not Assigned' for this status).\r\n   \"The volcano was relatively quiet until October 28 when an ash cloud rising to about 15,000 ft (4,600 m) ASL and drifting east was spotted in satellite imagery. On October 29, another cloud was 100 mi (160 km) long and drifting northeast at 10,000 ft (3,050 m) with little or no ash observed. A strong TA over the summit of the volcano was noted on October 30, but given the low-level nature of the recent activity, AVO did not elevate the Color Code or Alert Level.\r\n   \"On December 24, after a persistent TA near the summit, AVO returned to YELLOW/ADVISORY based on the observation that ash emission events often follow a protracted and strong thermal signal. About 1 week later, on January 2, 2009, Cleveland produced a short-lived ash burst to an estimated 20,000 ft (6,000 m) ASL.\"\r\nOn December 23, 2008,  AVO noted a persistent thermal anomaly at Cleveland and raised the volcanic alert level and the aviation color code to Advisory/Yellow on December 24. Clouds obscured satellite views of Cleveland until December 28, when a clear view showed that the December 23 anomaly persisted. \r\nFrom McGimsey and others (2014): \"On January 2, 2009, a brief but explosive ash emission was detected in satellite images. The plume was visible in satellite images for several hours, rose to about 20,000 ft (6 km), and drifted east-southeast up to 240 km (150 mi) downwind dispersing harmlessly over the North Pacific. Flowage deposits draped the flanks with the two largest flows (about 100 m wide; 328 ft) extending down the northeastern and northwestern flanks for at least 2 km (1.2 mi). The eruption produced airwaves that registered on seismometers on adjacent Umnak and Unalaska Islands, as well as on a pressure sensor at Shishaldin Volcano on Unimak Island. Similar airwaves were observed from the November 3, 2008 eruption of Cleveland (M. Haney, AVO/USGS, written commun., 2009, AVO internal log entry). \r\n\"No further activity was noted until the end of January when satellite images showed evidence of recent eruptive activity visible around the summit of Cleveland. Retrspective analysis on January 23 of prior satellite data indicated that a short-lived, low-level ash emission may have occurred early on the morning of January 21.\"","StartYear":2007,"StartMonth":6,"StartDay":null,"StartTime":null,"StartQualifier":1,"StartQualifierUnit":"Months","EndYear":2009,"EndMonth":1,"EndDay":21,"EndTime":null,"EndQualifier":2,"EndQualifierUnit":"Days","Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":589,"Name":"Pavlof 2007/8","Description":"   From McGimsey and others, (2011): \"Pavlof, one of the most frequently active volcanoes in the Aleutian arc, abruptly erupted on August 14, 2007, following an 11-year repose [see fig. 25 in original text]. The 31-day Strombolian eruption was preceded by less than 1 day of increased seismicity detected on the AVO seismic network, and produced a spatter-fed lava flow, minor ash clouds, and lahars that extended down the south flank into the sea. The following account is drawn in part from Waythomas and others (2008).\r\n   \"The previous eruption of Pavlof Volcano was September 1996-January 1997 (Neal and others, 1997; McGimsey and Wallace, 1999). Minor activity (snowmelt, ash dustings, steam plumes, sulfur emissions) was noted in 1999 and 2001, and in 2005, steaming was observed at adjacent Hague volcano [see table 4b in original text]. Nothing unusual was observed during the summer of 2007 and the seismicity was at background levels through August 13. Abruptly on the morning of August 14, the 5-station seismic network on Pavlof began recording low-frequency earthquakes occurring at a rate of 2 to 7 events every 10 minutes, a pattern that had preceded eruptions in 1996, 1986, 1983, and 1981 (McNutt, 1987; McNutt, 1989; Roach and others, 2001). Although NWS observers in Cold Bay (37 mi southwest) with clear views of the volcano could see no anomalous steaming or other activity, and clear satellite views of the summit that morning also showed no signs of activity, the dramatic increase in seismicity prompted AVO to raise the Aviation Color Code/Volcano Alert Level to YELLOW/ADVISORY.\r\n   \"During the night, an intense thermal anomaly (TA) was visible in satellite images (Advanced Very High Resolution Radiometer-AVHRR), and seismic activity continued to increase in both number and duration of events per hour, clear signs that the unrest was escalating. On the morning of August 15, based on observations of the TA and increasing seismicity, AVO elevated the Aviation Color Code/Volcano Alert Level to ORANGE/WATCH and announced that an eruption was expected. With the upgrade in color code, AVO began 24-hour surveillance of the volcano. Later in the day, AVO received eyewitness accounts from mariners of incandescent blocks rolling down the eastern-southeastern flank of the volcano during the previous night, beginning around midnight. Pilots reported a thin, low-level ash plume extending a few kilometers southwest from the summit. After receiving these reports, AVO established that the volcano was in eruption. Aerial photographs taken on August 15 show lava fountaining from a vent located about 200 m (650 ft) below the summit [see fig. 26 in original text].\r\n   \"On August 16, strong seismic signals recorded at a single station (PVV), located 8.5 km (5.3 mi) southeast of the summit, heralded the passage of lahars down the south flank; more than 41 lahar events would be recorded by this station over the next 29 days. Satellite observations of a strong thermal anomaly (TA) [see fig. 27 in original text] and nighttime incandescence at the summit reported by local residents were indications of vigorous lava eruption at the summit vent [see fig. 28 in original text]. The seismic network recorded long periods of volcanic tremor with repetitive explosions that indicated nearly continuous Strombolian eruption. In addition to the generation of lahars, this activity produced low-level ash clouds (5-6 km ASL; 3.1-3.7 mi), and a spatter-fed lava flow that descended the southeastern flank. By August 18, AVO personnel in the field reported that vigorous eruption of lava at the summit continued. Using a Forward Looking Infrared (FLIR) camera, they determined that a 20- to 50-m-wide, 65- to 165 ft-wide) 600 °C (1,112 °F) lava flow extended 565 m (1,850 ft) from the vent down the southeast flank [see figs. 29 and 30 in original text]. Thermal data collected the next day indicated that the outer part of this flow was about 140 °C (284 °F) and had cooled considerably. The vent crater for the last eruption of Pavlof, in 1996, was located on the upper northwestern side of the summit. For this eruption, the active vent migrated to the upper southeastern side, about 200 m (650 ft) below the summit [see figs. 31-33 in original text].\r\n   \"Seismicity at Pavlof was elevated and steady throughout the remainder of August and then began waxing and waning for the first week of September. A strong TA was present in satellite images, even through clouds, during this time. During the second week of September, the seismicity began showing signs of a steady decrease [see fig. 34 in original text], and by September 13, seismicity decreased to low levels and only a minor steam plume was visible above the volcano. A TA was last seen on September 15, and AVO declared that the activity had reached a lull by September 17. An AVO field crew with clear views reported that all eruptive activity had ceased during their visit on September 19, and the Aviation Color Code /Volcano Alert Level was downgraded to YELLOW/ADVISORY on September 20. The next 2 weeks of low seismicity and no further signs of activity or unrest prompted AVO to declare the eruption over (ending on September 13), and the Color Code/Volcano Alert Level was downgraded to GREEN/NORMAL on October 5.\r\n   \"Ash, a blocky lava flow, and multiple lahars were generated by this eruption. Mixed ash and steam clouds produced during the most energetic eruptive period, mid-August to mid-September, reached altitudes of 5-6 km (about 20,000 ft) ASL. The plumes were diffuse, drifted primarily to the southeast over the North Pacific Ocean, and many could not be detected in satellite imagery. No ash reportedly fell on nearby communities and there were no significant impacts to aviation. AVO deployed a DRUM aerosol impactor (particle collector) in Sand Point, 90 km (56 mi) east of Pavlof, and collected fine ash (2.5-0.1 µm). Although no visible ash fallout was observed during aerosol sampling, these results demonstrate that volcanic ash was present in respirable size fractions downwind of the volcano even during periods of low ash emissions (Peter Rinkleff and Cathy Cahill, AVO/UAFGI, written commun., 2010).\r\n   \"Analyzed samples from the lava flow are basaltic andesite in composition (53% SiO2), which is similar to the products of previous Pavlof eruptions (McNutt and others, 1991; Neal and McGimsey, 1997). Lahars were produced by interaction of hot blocks and spatter from the lava flow with snow and ice on the southeastern flank. The lahars inundated an area over 2 km2 (0.78 mi2) and formed a debris fan that extended 3.6 km (2.2 mi) from the base of the volcano into Pavlof Bay [see fig. 35 in original text].\"","StartYear":2007,"StartMonth":8,"StartDay":15,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2007,"EndMonth":9,"EndDay":13,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":4848,"Name":"Westdahl non-eruptive activity 2008","Description":"From Cameron and others, 2023: \"Throughout 2018, Westdahl volcano (an informal name that herein includes Westdahl Peak, Westdahl caldera, and associated intra- and extra-caldera features) continued its long-term steady inflation, which has persisted since the deformation was first observed after the installation of a GPS network on Unimak Island in 2008. An analysis of Westdahl volcano InSAR data by Lu and others (2003) indicated a shallow magma reservoir exists beneath the volcano; the continued inflation is consistent with an ongoing accumulation of magma at shallow depths. Westdahl volcano remained at GREEN and NORMAL throughout 2018.\"\r\nFrom Orr and others, 2023: \"In 2019, Westdahl volcano continued its long-term trend of steady inflation, which has persisted since the trend was first observed after the installation of a GNSS network on Unimak Island in 2008. An analysis of Westdahl volcano InSAR data by Lu and others (2003) indicated a magma reservoir exists beneath the volcano at a depth of about 6 km [3.7 mi] below sea level. Continued inflation of Westdahl volcano is consistent with an ongoing accumulation of melt at relatively shallow depths. The volcano remained at GREEN and NORMAL throughout 2019.\"","StartYear":2008,"StartMonth":1,"StartDay":1,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":"Years","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Westdahl","ParentVolcano":"Westdahl","VolcanoID":"ak322","ParentVolcanoID":"ak322"},{"ID":662,"Name":"Shishaldin 2008/1","Description":"From Neal and others (2011): \"AVO received a number of calls during 2008 regarding possible steam and ash emissions from Shishaldin. The first caller on January 8 reported a plume rising just a few thousand feet above the summit. On February 11, AVO received word from the National Weather Service of several pilot reports of a plume containing ash to an estimated 15,000 ft (4,600 m) ASL and extending south for about 25 mi (40 km). A check of seismicity showed nothing unusual that would reflect an increase in activity or ash emission. A one-time SIGMET was issued by National Weather Service. The following day, the USCG inquired about the status of the volcano and its potential for impacting operations in the area.\"","StartYear":2008,"StartMonth":1,"StartDay":8,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":603,"Name":"Veniaminof 2008/2","Description":"   From AVO's Volcanic Activity Notice on February 22, 2008: \"On February 22, 2008, several minor bursts of ash from Veniaminof were observed on AVO webcam images and recorded in seismic data this morning.  The bursts rose less than 9000 ft ASL (only a few hundred feet above the active intracaldera cinder cone), and were confined to the caldera.\"  Since February 22, AVO has continued to note elevated seismicity at Veniaminof and to view steam and occassional ash in Veniaminof webcam images.\r\n\r\nFrom Neal and others (2011): Intermittent low-level activity at Veniaminof continued in 2008 with minor phreatic ash emissions and periods of slightly elevated seismicity. Beginning in mid-February, seismicity (in the form of 1-2 minute tremor bursts with occasional harmonic banding) became slightly more energetic and AVO staff noted vapor plumes in web camera images from Perryville, 35 km (22 mi) south of the volcano.\r\n   \"A weak ash emission event was captured on the AVO web camera on February 22, noted during routine analysis by AVO and reported via email by a watchful citizen, prompting AVO to issue a YELLOW/ADVISORY. Minor eruptions of ash occurred about once every 20-30 minutes over several hours, producing small plumes that rose at most about 300 m (1,000 ft) above the intracaldera cinder and spatter cone [fig. 8; imageid 14025]. Some of these small bursts could be correlated with a clear multi-station seismic event [see fig. 9 in original text]. Ash clouds dissipated rapidly and did not extend beyond the caldera rim; in between bursts, a white water vapor plume was common. These were similar to those seen during 2005 (McGimsey and others, 2007).\r\n   \"On February 23, only a white vapor plume rose above the cone. Tremor bursts continued, increasing in intensity (both number of discrete volcano-tectonic earthquakes (VTs) and longer tremor episodes) on February 29. In response, AVO initiated additional checks of seismic data for the volcano and implemented a Real Time Seismic Amplitude (RSAM) alarm for Veniaminof (Murray and Endo, 1992). A pilot reported ash to 10,000 ft (3,050 m) on February 29 and the NWS issued a SIGMET. Perryville residents using a telescope reported seeing large blocks, orange in color, thrown out of the plume during daylight hours on February 28. The lack of a thermal anomaly or night time reports of incandescence suggests these ballistic objects probably were altered and oxidized lava bombs rather than fresh, hot (and thus, 'glowing') magmatic ejecta.\r\n   \"In addition to more frequent analysis of seismicity, AVO initiated automatic ash dispersal runs using the PUFF model (Searcy and others, 1998) for hypothetical Veniaminof eruptions.\r\n   \"Seismicity and emissions decreased in early March and AVO discontinued the heightened seismic watch. A March 4 ASTER image showed a small vapor plume emanating from the intracaldera cone but no anomalous temperatures indicative of significant activity (R.L. Wessels, USGS, written commun., 2008).\r\n   \"On May 3, after several months of no further ash emission events, AVO downgraded Veniaminof to GREEN/NORMAL, where it remained for the rest of 2008 and into 2009.\"","StartYear":2008,"StartMonth":2,"StartDay":22,"StartTime":null,"StartQualifier":7,"StartQualifierUnit":"Days","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Veniaminof","ParentVolcano":"Veniaminof","VolcanoID":"ak301","ParentVolcanoID":"ak301"},{"ID":652,"Name":"Aniakchak 2008/3","Description":"Seismometers at Aniakchak Volcano appeared to record anomalous seismicty at Aniakchak during the spring of 2008. Further analysis revealed that the signals were a product of icing on the seismometers, and not of volcanic origin.\r\nFrom Neal and others (2011): \"AVO seismic analysts noted a swarm of seismic events at Aniakchak during routine seismic checks of Alaskan volcanoes on March 8. The activity continued intermittently over the next week with events occurring as frequently as 5-10 per hour. Interpreting the significance of the signals was hampered by the fact that only a single station in the Aniakchak network, ANNW, was operating at the time. AVO increased seismic watch frequency for Aniakchak in response and contemplated organizing a winter-time field visit to restore more of the seismic network.\r\n   \"Subsequently, an evaluation of historical seismicity at Aniakchak during times of more complete network operation suggested that the anomalous signals were likely weather-related (Katrina Jacobs, AVO/UAFGI, written commun., 2008). Similar swarms had occurred on a number of occasions between 2005 and 2008, but none were typical multi-station volcanic events and all showed a strong correlation with time of day. Years of maintenance efforts at the Aniakchak network documented a strong vulnerability of sites to heavy icing that could have been responsible for the intermittent seismic signals. Based on this, an AVO field response was canceled.\"","StartYear":2008,"StartMonth":3,"StartDay":8,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2008,"EndMonth":3,"EndDay":14,"EndTime":null,"EndQualifier":2,"EndQualifierUnit":"Days","Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":672,"Name":"Shishaldin 2008/6","Description":"From Neal and others (2011): \"On June 3, AVO received a pilot report of a steam plume rising about 2,000 ft (610 m) above the summit. On July 27, AVO was contacted by a mariner from the fishing vessel Castle Cape who reported Shishaldin 'puffing' on July 26 between about 8 p.m. and 12 a.m. local time. He described ash falling from the dissipating puffs. For all of these reports, there were no unequivocal correlative changes in seismicity, nor did any ash signal or thermal anomaly appear in satellite images. On July 29, AVO staff flying by Shishaldin from Dutch Harbor en route to Anchorage noted a faint wisp of vapor from the summit crater; there was a hint of dark discoloration high on the east flank, but views were quite distant. AVO received images of the volcano from a NOAA scientist on July 30 and several additional pilot reports of a steam plume from Shishaldin arrived on August 3. It is possible that this spike in reports reflected increased vigilance on the part of pilots and others traveling in the Aleutians in the wake of the highly explosive and continuing eruption of Okmok Volcano about 300 km (190 mi) west of Shishaldin. Shishaldin also is easily visible from the air on approach into Dutch Harbor.\r\n   \"AVO staff and colleagues from the Plate Boundary Observatory field team conducted instrument maintenance, installed 13 GPS stations, a broadband seismometer, 6 borehole tiltmeters, and a web camera, and relocated 4 seismic stations on Unimak Island from July 30 to August 22, 2008. They noted no obvious evidence of recent ash fall on the surface although they did observe some discoloration of the upper ice and snow cover, along with typical, weak fumarolic emission from the summit crater [figs. 10; imageid 15239, and 11; imageid 31882].\"","StartYear":2008,"StartMonth":6,"StartDay":3,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2008,"EndMonth":8,"EndDay":3,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":604,"Name":"Ahmanilix 2008/7","Description":"From Neal and others (2011): \"Okmok Volcano, a 10-km (6.2-mi) diameter Holocene caldera system in the central Aleutians [fig. 14; imageid 13283], began a protracted explosive eruption on July 12. The opening explosions consumed a portion of intracaldera Cone D within the east-central sector of the caldera, reaming several new craters into the caldera floor. Eruptive activity began only a few hours after a subtle increase in the rate of earthquakes followed by a short swarm sequence, both noted only in retrospect. Over the next 5 weeks, several hundred million cubic meters of tephra and lahar deposits blanketed much of northeast Umnak Island. Within the caldera, nearly continuous hydrovolcanic explosions accumulated many tens of meters of wet, mostly fine-grained tephra. Explosive activity completely disrupted existing groundwater and standing water bodies within the caldera, formed new lakes, and constructed a new tephra cone about 100-200 m (330-660 ft) high. This eruption was the first dominantly phreatomagmatic volcanic event in the United States since the Ukinrek Maars eruption in 1977. The following summary is taken largely from Larsen and others (2009).\r\n   \"Other than the seismicity recognized in hindsight, AVO noted no clear signs of precursory unrest at Okmok prior to the eruption onset. In fact, during the 2 months prior to July 12, Okmok produced only three earthquakes and no tremor episodes (intermittent tremor episodes had been recorded since the seismic network was installed in 2003 and had continued into mid-2005; Reyes and McNutt, 2008). Campaign and continuous GPS data had recorded nearly continuous inflation from 1997 to 2005, quiescence between 2005 and 2007, and notable (but not unprecedented) inflation in early 2008. Pre-eruptive displacements measured by GPS and InSAR indicated inflation of a pressure source about 2.6-3.2 km (1.6-2.0 mi) below sea level and underneath the approximate center of the caldera (Lu and others, 2005; Fournier and others, 2009).\r\n   \"AVO was first notified of the eruption by the USCG who had been contacted by the caretaker of Bering Pacific Ranch at Fort Glenn [Fort Glenn is a former U.S. Army base that now houses a cattle ranch operation about 10 km (6.2 mi) southeast of the caldera rim]. The caretaker and his family reported wet volcanic ash falling as they were evacuating the island first by helicopter and later by boat. An immediate check of Okmok seismicity by the AVO duty scientist confirmed that an eruption was in progress. AVO issued a notice of the eruption declaring Aviation Color Code RED and Volcano Alert Level WARNING and commenced 24-hour operations to respond to the event.\r\n   \"In addition to 24-hour staffing of the operations room in Anchorage, AVO mounted two helicopter-supported field responses to the eruption. The first operated from Unalaska between July 29 and August 5 and the second was based at Fort Glenn over a week in mid-September about 3 weeks after the eruption had ended. AVO received photographs taken by Fort Glenn ranch caretaker Lonnie Kennedy on several occasions. These photographs along with images from commercial and USCG aircraft, satellite imagery, and mariner accounts provided critical visual documentation of the eruption through time.\r\n   \"The most energetic phase of the eruption occurred over the first 10 hours of activity on July 12. The first satellite images of the ash plume were geostationary operational environmental satellite (GOES) images starting at 20:00 UTC on July 12. By 22:12 UTC, the ash cloud extended east over much of Unalaska Island [fig. 15; imageid 14279]. Both geometric image analysis of GOES and comparison of cloud motion with the PUFF ash dispersion model indicated a maximum initial column height of approximately 16 km (52,000 ft) ASL. Photographs of the eruption column by crews of a USCG C-130 and an Alaska Airlines jet taken about 5-6 hours into the eruption show a vertical, gray, ash-rich column rising into meteorological cloud layers; the top of the eruption plume appeared white and was estimated visually to be 30,000-35,000 ft (9,100 m-10,700 m) ASL. The ground was obscured and the aircraft too distant to make out any detail at the base of the eruption column.\r\n   \"The opening explosions and heavy tephra fall destroyed or disabled several AVO seismometers and continuously recording GPS instruments, however the remaining network density was sufficient to track the eruption. From July 13 through the end of the month, seismicity varied but remained well below the intensity of the opening eruption sequence on July 12. Eruption columns and clouds seen in satellite imagery and by passing aircraft varied significantly in altitude although these changes were not often in phase with recorded seismic amplitude (Larsen and others, 2009; table 5 in Neal and others 2011). Characteristics of most eruption clouds implicated the continuous involvement of water in the eruption process. On July 13, a Moderate Resolution Imaging Spectroradiometer (MODIS) satellite image showed two plumes -- one dark and ash rich and the other light in color and inferred to be very rich in water vapor -- emanating from the eastern portion of the caldera floor. Between July 13 and 21, photographs from Alaska Airlines and aerial observations by AVO staff from a USCG plane showed a light-colored plume with a wide base and multiple potential sources of ash explosions [fig. 16; imageid 14436].\r\n   \"Evacuated Fort Glenn ranch caretaker Lonnie Kennedy returned to the island on July 23 and, over the next several days, photographed eruption impacts and continuing ash emission and ash fall in the vicinity of the caldera. Kennedy documented ongoing muddy water flow across the lowlands surrounding the ranch; lahars in several drainages north of the ranch had been sufficiently energetic to destroy pre-existing wooden bridges and culverts and cause severe bank erosion. Dramatic new deltas had formed at the mouths of a number of creeks draining the northeast and southeast flanks of Okmok [fig. 17; imageid 15446]. The exact timing of lahar activity during the first days of the Okmok eruption is uncertain. It is also not clear if lahar formation was due to rain-remobilization of tephra, syn-eruptive condensation of water vapor entrained in the eruption cloud (W. Scott, USGS, written commun., 2008), dewatering of wet tephra fall, melting of snowpack, or some combination of these or other processes. Overbank deposits and the presence of large boulders atop the surface of the 2008 lahar fan at the mouth of Crater Creek (Crater Creek drains the caldera northwestward into the Bering Sea) suggest temporarily high discharge rates possibly caused by a sudden release of water from the caldera early in the eruption.\r\n   \"Kennedy's aerial photographs of the caldera from August 1 show the upper Crater containing an active, braided channel of muddy water indicating some drainage from the caldera. The terrain immediately east of the caldera was thickly covered in light brown to gray tephra. Deep rills and dendritic drainage networks existed on most surfaces; at higher elevations, the pre-eruption snowpack was visible beneath the 2008 debris, and water flowed from the base of the snowpack in many places. A partially clear view into the caldera on August 1 showed ash and water-vapor-rich clouds boiling from at least two point sources on the northwest flank of Cone D and just to the west of Cone D [fig. 18; imageid 15666]. Dark collars of debris enclosed each locus of venting. The pre-eruption lake northeast of Cone D had been significantly modified: standing water covered a much smaller area and what had been the lake was now a surface of tephra and scattered ponds.\r\n   \"The first AVO crew on scene in late July was unable to land near the caldera due to active ash emission. They focused on documenting the extent and character of ash fall and lahar deposits outside the caldera, taking observations of the ongoing eruption, repairing a key data repeater site on Makushin Volcano on Unalaska Island, and collecting samples and eye-witness accounts. They obtained some close-up views into the caldera and also distant views of the eruption column from the Fort Glenn ranch. On August 2 and 3, the eruption column had increased in intensity, height, and ash content [figs. 19; imageid 14700 and 20; imageid 14718]. This change was coincident with an increase in amplitude of seismic tremor. AVO crew observations, photographs, and film footage during this time of heightened activity suggest a migration of the location of active venting on the caldera floor over the span of minutes. On overflights near the eruption site, the field crew observed a ground-hugging cloud of tan-colored ash covering the caldera floor and obscuring views of the immediate area. In glimpses of the caldera floor near the site of the pre-eruption lake near Cone D, they noted chaotic, disrupted terrain and channels of flowing water.\r\n   \"Due to the renewed intensity of the eruption, AVO elevated the Aviation Color Code and Volcano Alert Level again to RED/WARNING early on the morning of August 2 [see table 5 in original text], and the caretaker and family at the Fort Glenn ranch decided to evacuate for the second time. During the last days of July and the first days of August, prevailing winds shifted to be out of the northeast.\r\n   \"Subsequently, over the first 2 weeks of August, eruption intensity and cloud height generally decreased and ash emission ceased altogether by August 19. A USGS helicopter crew working in the Aleutians entered the caldera on August 13 during the waning phase of eruption and photographed a single active vent enclosed within a steep-sided tephra cone [figs. 21; imageid 15120 and 22; imageid 15119]. Dark ash boiled out of the tephra cone surrounded by a collar of white water vapor; winds were from the northwest sending the ash and water vapor cloud over the summit of Cone D and the caldera rim. A significant lake was now present near the site of the pre-eruption lake and the landscape was completely covered with dark gray ash. The surface north of Cone D was pocked with craters several meters to several tens of meters in diameter. A series of scallop-margined basins and coalesced craters, some hosting standing water, extended in a line west of Cone D.\r\n   \"On August 23, about 1 week after the end of the eruption, Lonnie Kennedy again photographed the eastern caldera from the air. Although Crater Creek was open and flowing just inside the caldera, a through-going surface connection between Crater Creek and the growing lakes had not been established. Wind re-suspended a tan-colored ash in the vicinity of the largest of the new vents.\r\n   \"AVO's week-long September expedition to Okmok gathered reconnaissance information about the eruption deposits and impacts, repaired some seismic and GPS instruments, and deployed additional GPS recording stations (some of which were retrieved in the summer of 2009 by the Plate Boundary Observatory field crew). Most tephra sections excavated within and outside the caldera exposed planar to slightly wavy-bedded, fine-grained fall and surge deposits. Northeast of the vent region where tephra accumulation was thickest, the basal unit from the July 12 opening phase was a coarse ash-lapilli fall deposit; individual clasts were coated with a very fine ash [fig. 23; imageid 31902]. Evidence of significant water interaction throughout the 2008 tephra sequence includes (1) very high porosity of individual beds reflecting post-emplacement de-watering; (2) plastering texture on perpendicular surfaces facing the vent; (3) abundant accretionary lapilli; (4) overall fine-grained nature of the deposit. Outside the caldera, excavated sections contained mostly fall deposits with thin and discontinuous aeolian horizons; no clear evidence for energetic, far-traveled, extra-caldera surges was noted.\r\n   \"Field observations in September combined with analysis of photographs and satellite images indicate that the eruption occurred from a series of vents that opened during the first 2 weeks of the eruption. These vents extended in a roughly linear zone about 2 km (1.2 mi) long across the caldera floor [figs. 24; imageid 15480 and 25; iin original text]. One crater formed next to, and eventually captured and drained, the pre-existing lake northeast of Cone D. A tephra cone ('New Cone') had been constructed atop the longest-lived 2008 vent [fig. 26; imageid 15476]. By mid-September, the explosion and collapse craters to the west of Cone D had filled with water and formed a new lake ('New Lake') about 0.6 km2 (0.2 mi2) in area [figs. 24; imageid 15480 and 25; in original text].\r\n   \"Eruptive products from the 2008 sequence are basaltic andesite in composition, slightly more silicic than the range of Okmok chemistry represented by other post-caldera (last about 2,000 years BP) eruptions (Larsen and others, 2009). The fine-grained nature of most 2008 tephra and the lack of an effusive phase pose a challenge to understanding changes in eruption chemistry with time. Coarse juvenile lapilli from the opening phase of the 2008 eruption were collected on the caldera rim just above the outlet of Crater Creek in a notch through the caldera wall informally called 'The Gates' [fig. 14; imageid 13283]; this location was near the main northeast axis of deposition. Clast types in the July 12 opening tephra range from dense to vesicular scoria and pumice, and crystal fragments (Mariah Tilman, AVO/UAFGI, written commun., 2008). Some dense clasts may represent accidental lithics incorporated during the opening explosions through the caldera floor and lava flows of Cone D. Larger frothy pumiceous clasts were found along the shoreline of one of the shallow lakes within the caldera; because they are not in place, they cannot be confidently assigned to the 2008 event, but they were fresh-looking, fragile, and most likely represent material erupted on July 12. These clasts are up to 5-10 cm (2-4 in.) across and are light to dark brown, vesicular, scoriaceous pumice with irregular, fractured chill rinds.\r\n   \"Following cessation of eruption in mid-August, seismicity remained relatively low with occasional bursts of higher amplitude tremor. AVO downgraded the Aviation Color Code and Volcano Alert Level to YELLOW/ADVISORY on August 27 [see table in original text] after a week with no ash clouds discerned in satellite images. Occasional thermal anomalies were visible by satellite and are likely attributable to the still-warm vent area, fumaroles, and/or lakes within the caldera. By mid-November, after 3 months of steadily decreasing seismicity, AVO changed the Aviation Color Code to GREEN and Volcanic Alert Level to NORMAL. In the accompanying remarks, AVO indicated that despite the cessation of eruptive activity, hazardous conditions persisted. Unstable, muddy surfaces and slopes of new volcanic debris within the caldera could collapse at any time. New and rapidly changing lakes, ponds, and multiple steep-walled craters through the new tephra blanket would present a hazard to anyone visiting the caldera. Magmatic gases and areas of high temperature could persist around the new tephra cone. All drainages leading downslope from the rim of the caldera are susceptible to remobilization of ash and other loose debris during heavy rains and spring melt. The Crater Creek drainage on the north-northeast flank of Okmok was considered especially vulnerable to sudden flooding events if tephra dams within the caldera were to fail suddenly and release impounded water.\r\n   \"AVO maintained 24-hour staffing from July 12 through August 28. Over the course of the eruption, AVO issued 17 Volcanic Activity Notices and two Information Statements.\r\n   \"Eruption impacts were modest except for the significant disruption to the ranch caretaker family on Umnak Island who evacuated twice from the island including the first time under great duress during the most energetic phase at the start of the eruption. Primitive roads on the east and south flanks of the caldera were cut by lahars and water floods and rendered at least temporarily impassable. Ash accumulation suppressed grass growth that resulted in diminished over-winter feed for the livestock that roam the island. According to the Kennedy family, it is possible that an increased number of cattle perished in the winter of 2008-09 because of this (Susan Kennedy, written commun., 2009). The island also hosts a large number of caribou, although we are unaware of any systematic population counts to gauge the impacts of the eruption. Offshore Umnak Island, volcanic sediment delivered to the coastline built significant new lahar deltas and fishermen reported dramatic changes to bottom conditions in the weeks after the eruption (Lonnie Kennedy, oral commun., 2008) Several boats received minor to trace ash fall with no ill-effects reported other than a single collapsed air filter (Dustin Dickerson, oral commun., 2008). Out of concern for the effects of ash fall, the U.S.Coast Guard closed Umnak Pass for several days in the immediate aftermath of July 12.\r\n   \"Over the course of the eruption, trace amounts of ash fell on several occasions in Unalaska-Dutch Harbor 120 km (75 mi) northeast of the volcano. The airport closed briefly to allow for clean-up of the runway and taxi ways. Cannery workers and other residents were concerned about impacts of the ash fall, however slight, on their health, and AVO worked with local health care providers and cannery management, and with the Alaska Department of Environmental Conservation Air Quality Division to issue health related information. AVO and UAFGI staff installed a 3 stage DRUM impactor air sampler in Unalaska to sample volcanic particulate from the ash fall events (Peter Rinkleff, AVO/UAFGI, written commun., 2008). AVO staff also traveled to Unalaska in late July to meet with the local Director of Public Safety, the resident Department of Environmental Conservation employee, U.S. Coast Guard Station Chief, Native Health clinic supervisor, cannery management, contract weather observer, and airport supervisor and maintenance manager about their concerns and accounts of the eruption. AVO staff participated in local radio interviews, gave a public lecture on the eruption, and met with members of the community to gather eyewitness accounts and answer questions.\r\n   \"AVO received both ash and pumice samples from citizens in Unalaska. By July 24, some Unalaska residents reported pea to gravel sized light to dark brown pumice washing ashore on several beaches in Unalaska; based on the timing and physical characteristics of the clasts, it is possible that these represented marine transported pumice from the July 12 eruption onset. Whether pumice of this size fell at sea or was washed into the sea by lahars or other flowage processes on Umnak is unknown.\r\n   \"Flights across the North Pacific were impacted for a period of several days in mid-July as the July 12 eruption cloud drifted north and east over the Gulf of Alaska. During the week following the eruption, aircraft over the lower 48 States observed and photographed the remnant of the Okmok aerosol cloud as it transited across North America at elevations in excess of 30,000 ft (9,100 m) ASL. NWS maintained a nearly constant SIGMET for the area impacted by ongoing ash production during the event; SIGMET boundaries were modified over time on the basis of pilot reports of ash cloud drift as well as satellite images showing the cloud combined with forecast motion.\"","StartYear":2008,"StartMonth":7,"StartDay":12,"StartTime":"11:43:00","StartQualifier":null,"StartQualifierUnit":null,"EndYear":2008,"EndMonth":8,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Ahmanilix","ParentVolcano":"Okmok","VolcanoID":"ak347","ParentVolcanoID":"ak206"},{"ID":605,"Name":"Kasatochi 2008/8","Description":"  From Waythomas and others, 2008: \"Kasatochi Volcano, a small, 3 km diameter, 300 m high, island volcano in the central Aleutian Islands of Alaska (52.1693 degrees N latitude, 175.5113 degrees W longitude) erupted violently on August 7, 2008 after an intense period of precursory seismic activity. Kasatochi has received little study by volcanologists and has had no confirmed historical eruptions; it is not monitored with seismic instruments on Kasatochi Island.  The island is part of the Alaska Maritime National Wildlife Refuge and has been a long-term study site for the US Fish and Wildlife Service (USFWS), which has annually deployed scientists to the island to monitor seabirds for 13 years.  \r\n   \"The 2008 eruption occurred less than a week after USFWS personnel on the island began feeling small tremors. On August 4, the USFWS contacted the Alaska Volcano Observatory (AVO) to report these observations. At the time, the reports of earthquake activity were considered normal, as the area has frequent, and sometimes large, earthquakes and an early analysis suggested that the activity did not appear volcanic in origin. By early evening August 6, it became clear that a significant volcanic earthquake swarm was occurring in the vicinity of Kasatochi Island and that the scientists on the island could be endangered should they remain at their camp. At about 7 PM AKDT, AVO issued a formal Volcanic Activity Notice stating that Kasatochi volcano had become restless and raised the aviation color code and volcano alert level to yellow/advisory. AVO also recommended that the scientists on the island be evacuated as soon as possible.\r\n   \"Strong seismicity continued throughout the evening and into the next day. At about 10:30 AM AKDT August 7, a magnitude 5.8 earthquake occurred within a few km of Kasatochi. Soon after this earthquake, seismic instruments on nearby Great Sitkin Volcano began recording periods of strong volcanic tremor usually indicative of fluid (magma, gas, or both) motion and often associated with eruptive activity. AVO responded by raising the volcano-alert notification to orange/watch at 1:57 PM AKDT, indicating that an eruption was possible. Just after 2 PM AKDT, satellite images confirmed an eruption of Kasatochi was in progress and AVO issued a Volcanic Activity Notice announcing an aviation color code and alert level of red/warning. Thankfully, a local fishing boat had safely evacuated the two scientists less than 30 minutes prior to the opening blast.\r\n   \"The eruption was characterized by three distinct explosions that were detected by the seismic network on Great Sitkin Volcano, at approximately 2:01 PM, 5:50 PM, and 8:35 PM AKDT. The first two events produced relatively ash-poor, but gas-charged, eruption clouds that reached 45,000 - 50,000 feet above sea level and apparently no or very little local ash fall. The third event generated an ash- and gas-rich plume that also rose to 45,000 - 50,000 feet and produced several inches of ash and lapilli fall over the ocean and on islands southwest of Kasatochi, including minor amounts on Adak Island, the closest island with a year-round population, about 50 miles from the volcano. Boats in the vicinity of the volcano reported 4-5 inches of coarse grained ash fall, darkening skies, and lightning, likely caused by static electricity in the ash plume.  The third event was followed by about 17 hours of continuous ash emission as determined from satellite data. The cumulative volcanic cloud from Kasatochi (\u003ca href=\"http://www.avo.alaska.edu/image.php?id=15049\"\u003eFig. 1\u003c/a\u003e) contained a large amount of sulfur dioxide gas that was detected by the Ozone Monitoring Instrument on NASA's EOS-Aura satellite for more than a week after the eruption as the cloud circled the globe. The ash and gas cloud drifted east and interfered with air travel between Alaska and the conterminous US causing at least 40 flight cancellations and stranding many thousands of travelers. The cloud was visible for thousands of miles downwind and apparently was the cause of some brilliant sunsets over the Midwestern US. \r\n   \"AVO and USFWS scientists visited Kasatochi Island on August 22 and 23. Photographs of what they found can be seen on the AVO web site (www.avo.alaska.edu). The visit confirmed that a major eruption had occurred, and thick deposits of gray volcaniclastic debris and ash now covered the formerly lush volcanic island that was home to over a hundred thousand seabirds (\u003ca href=\"http://www.avo.alaska.edu/image.php?id=16101\"\u003eFig. 2\u003c/a\u003e, \u003ca href=\"http://www.avo.alaska.edu/image.php?id=16102\"\u003e Fig. 3\u003c/a\u003e). Pyroclastic-flow deposits exposed along the new coastline, now about 400 m further into the sea were noticeably warm when visited on August 22 and 23 (\u003ca href=\"http://www.avo.alaska.edu/image.php?id=15306\"\u003eFig. 4\u003c/a\u003e). These deposits recorded significant collapse of the vertical eruption column to produce hot avalanches of rock debris, gas, and ash. The pyroclastic flows also initiated a small tsunami that was recorded by tide gages at Atka, Adak and Amchitka. Attempts to locate the USFWS camp were unsuccessful and the ca. 75-year-old cabin was either swept from the island or buried beneath the new deposits. A few thousand chicks of nesting seabirds had not yet left their nesting burrows or crevices and were most likely entombed under the ash. Few signs of life remained on the former major seabird colony. The summit crater had enlarged in diameter by about 100 m and the crater floor was steaming profusely from a number of circular vents and warm areas on the crater floor. \r\n   \"The 2008 eruption of Kastochi was a significant test of AVO's ability to assess the reawakening of a seismically unmonitored and little-studied, remote volcano. Fortunately, the earthquake activity was strong enough to be recorded on existing seismic networks on nearby volcanoes and scientists on the island were able to communicate with local contacts to coordinate a rescue. These seismic networks were installed with funding from the Federal Aviation Administration to reduce the hazard to aviation from volcanic ash. In this case, the instrumentation was crucial in recognizing the signs of significant unrest and potential for major eruptive activity, saving the lives of two biologists and providing the aviation community with advance warning of a possible eruption. AVO and its partner agencies in DOI now have a unique opportunity to evaluate the response of Kasatochi's ecosystem to a major volcanic event and to address how the landscape evolves following significant physical, chemical, and biological changes. \"\r\nFor a record of AVO's Information Statements and Weekly Updates during the eruption, please see  \u003ca target=\"_blank\"  href=\"http://www.avo.alaska.edu/activity/Kasatochi.php\"\u003ehttp://www.avo.alaska.edu/activity/Kasatochi.php\u003c/a\u003e.\r\n  For an account of the biologist's evaucation from Kasatochi, please see Rozell, 2010.\r\n\r\nFrom Neal and others (2011): \"Analyzed 2008 juvenile pumice clasts are crystal-rich andesite with plagioclase, orthopyroxene, clinopyroxene, hornblende, and Ti-magnetite phenocrysts in a clear glass matrix that also contains elongate plagioclase, pyroxene, and amphibole microlites. Preliminary petrology and melt inclusion work suggests pre-eruption storage at depths of about 6.5-12.5 km (4-8 mi) and rapid ascent to the surface (Izbekov, 2008; Izbekov and others, 2009). Gabbroic inclusions in Kasatochi pumice contained amphibole up to 11 cm (4 in.) in length (P. Izbekov, AVO/UAFGI and C. Nye, AVO/ADGGS written commun., 2010).\r\n   \"Biological impacts of the eruption were significant in the short term; quantifying impacts to plant and animal inhabitants and the nearby ecosystem is the subject of an ongoing interdisciplinary research program (Buchheit and Ford, 2008). Aviation impacts also were severe. The ash and aerosol cloud drifted east during the week following the eruption interfering with air travel between Alaska and the conterminous U.S., causing at least 40 flight cancellations, and stranding many thousands of travelers. At least one commercial jet aircraft flew through what the flight crew reported as a thin volcanic cloud layer prompting an inspection and precautionary replacement of some equipment. A second aircraft over Canada also reported entering a sulfurous, yellowish-brown haze layer (Guffanti and others, 2010). In both cases, no in-flight malfunctions were noted and there was no discernible damage or verifiable volcanic ash contamination upon inspection.\r\n   \"The eruption cloud was visible for thousands of miles downwind and was the cause of some brilliant sunsets over the Midwestern U.S. The SO2 cloud from this eruption was detected by the Ozone Monitoring Instrument on NASA’s EOS-Aura satellite as it circled the globe. A small tsunami [35 cm (14 in.) in amplitude] associated with the eruption was recorded by a tide gage at Adak, however, no damage was reported.\"","StartYear":2008,"StartMonth":8,"StartDay":7,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2008,"EndMonth":8,"EndDay":12,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kasatochi","ParentVolcano":"Kasatochi","VolcanoID":"ak146","ParentVolcanoID":"ak146"},{"ID":761,"Name":"Shishaldin 2009/1","Description":"From McGimsey and others (2014): \"Shishaldin Volcano is one of the most active volcanoes of the Aleutian arc. Minor unrest and eruptive activity have been documented for all but a couple of the past 20 years. In 2008, Shishaldin maintained the pattern of producing steam plumes, occasionally with minor phreatic ash emissions (Neal and others, 2011). Thermal anomalies (TA) were observed on September 5 and December 18, 2008. This activity increased in early 2009 with the occurrence of a significant 2-pixel thermal anomaly and a slight increase in seismicity on January 5. AVO issued a VAN the following day upgrading the Aviation Color Code/Volcano Alert Level to YELLOW/ADVISORY. That day, pilots and ground observers reported a constant steam plume rising about 1,000 ft (about 300 m) above the summit and trailing of 16-25 km (10-15 mi) to the southeast. Satellite views on January 8 showed a steam-filled crater and no ash on the snow-covered flanks, and a pilot's photograph taken January 11 shows a pulsing steam plume. A few days later, on January 13, AVO seismologists identified low-amplitude, minor tremor in the seismicity at Shishaldin, which continued for several weeks and then apparently faded out.\r\n\"On January 17, the on-island Shishaldin Web camera, which had been out of service since October 22, 2008, was made operational again, although images were not recorded until February 20. Over the next couple of weeks, thermal anomalies were few, seismicity remained low, and although the reports of steaming continued, steam emissions from Shishaldin are considered normal. The return to background conditions prompted AVO to downgrade the Color Code/Alert Level to GREEN/NORMAL on February 11, 2009. A February 28 Web camera image shows a modest steam plume rising from the summit. Image quality problems with the Web camera in March and April led to the camera being taken off-line on April 30.\r\n\"Over the next 7 weeks, occasional thermal anomalies were observed along with continuous low-level tremor, which was not considered unusual activity for Shishaldin. Then, on April 7, a PenAir pilot reported Shishaldin streaming more vigorously than in the previous 16 months of observing during his weekly flights by the volcano. A thermal anomaly was reported in satellite imagery that day as well. Activity continued during the next couple of weeks, and on April 20, thermal activity at the summit spiked with the recording of multiple thermal anomalies having saturated pixels, indicative of high ground temperatures (more than 300C; about 600F). This level of thermal activity was last observed at Shishaldin during the run-up to the 1999 eruption (J. Dehn, AVO UAFGI, 2009 internal log entry 31659). A pilot reported steaming on May 5, and an observer on a different flight that day reported also seeing dark colored, linear features on the northern side of the summit. These would later be interpreted to be minor streams of 'dirty' water; no significant deposits were produced.\r\n\"Throughout June, thermal anomalies were detected on about one-third of the days, with a particular strong anomaly noted on June 9; no unusual seismicity was detected. A clustering of thermal anomalies appeared to coincide with favorable vertical view angles. On the night of June 25, an ASTER thermal infrared satellite image showed a thermal anomaly and a 22-km-long (14 mi) steam plume extending east-northeast from Shishaldin. Clouds blanketed most of Unimak Island, but the top of Shishaldin was visible above the cloud deck. An observer in Cold Bay, Alaska, called on June 29 to report increased steaming at Shishaldin during the previous couple of days. During the first full week of July, thermal anomalies increased in strength, with a return of saturated pixels (high ground temperatures). Based on this trend, as well as the persistence of the thermal anomaly, AVO elevated the Color Code/Alert Level to\r\nYELLOW/ADVISORY on July 10, 2009. Neither seismicity nor deformation had changed appreciably, and satellite data showed no significant sulfur dioxide gas emissions.\r\n\"Airborne emissions were detected in the daily analysis of satellite imagery on July 13, which was a day of rare, cloud free conditions, and a pilot also reported a steam plume rising 2,000 ft (600 m) above Shishaldin and moving to the northwest. Then, on July 15, the Ozone Monitoring Instrument (OMI) satellite imagery appeared to show a small plume-like cloud rich in SO2 originating at Shishaldin; a PUFF simulation using current winds supported the emission source as being Shishaldin.\r\n\"During the remainder of July and the first half of August, weather permitting, views of Shishaldin showed steaming from the summit. Thermal anomalies were observed in satellite images, particularly in August. A Plate Boundary Observatory (PBO) crew working on Unimak Island replaced the AVO Web camera for Shishaldin, and it began recording images on August 10; the Web camera would go off-line again on October 11, 2009.\r\n\"Following the report of a thermal anomaly on August 16, no more anomalies were detected through the remainder of 2009 except for a weak thermal anomaly on November 2. In mid-September, seemingly anomalous air waves were detected on pressure-sensors located on Shishaldin (station SSLN_BDF), which could be indicative of minor explosions. Retrospective analysis of pressure-sensor data for the previous 2 months revealed that these air waves are common phenomenon and correlated to episodic gas bursts, as documented in 2003-04 (Petersen and McNutt, 2007).\r\n\"The persistent absence of thermal anomalies, decrease in steam emissions, and seismicity considered to be within background levels, prompted AVO to downgrade the Aviation Color Code/Volcano Alert Level for Shishaldin to GREEN/NORMAL on October 19, 2009. The volcano remained quiet for the remainder of 2009.\"","StartYear":2009,"StartMonth":1,"StartDay":5,"StartTime":null,"StartQualifier":1,"StartQualifierUnit":"Months","EndYear":2009,"EndMonth":8,"EndDay":16,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":811,"Name":"Veniaminof 2009/1","Description":"From McGimsey and others (2014): \"On January 8, 2009, a pilot reported seeing a wispy, light-gray plume between 6,500 and 10,500 ft (1,980 and 3,200 m), and extending 28 km (15 mi) downwind from the volcano. A passenger in an aircraft took a photograph of the plume. The AVO/USGS web camera located at nearby Perryville also captured the plume that day. \r\n   \"AVO remote sensing experts interpreted the 'gray tone' attributed to the plume to be backscatter shadow from the plume rather than ash content. Similar steaming was recorded in web camera images most of the previous week and again during the week of March 17. The web camera became inoperative on March 17 due to relocation of the village office hosting the camera. The camera would not come back online until May 27, 2009.\r\n   \"In response to an increase in seismic activity across the entire network, AVO issued a VAN on May 7, 2009, elevating the Aviation Color Code/Volcanic Alert Level to YELLOW/ADVISORY. Because the web camera was inoperative, calls to local observers on May 9 produced reports of a 'steady stream of light steam, with occasional small puffs.' Low-level tremor was recorded the week of May 18, but the activity soon diminished, and with no further visual reports of activity, on May 26, 2009, AVO issued a VAN downgrading the volcano to GREEN/NORMAL. A few days later, on May 29, tremor returned and abruptly increased later in the day. The web camera was once again operating, but the view on this day was obscured by clouds. Nothing unusual was noted in satellite images. Tremor continued through May 30, 2009, but at a lower amplitude than previously recorded, and then diminished entirely. Thus, no change in status was forthcoming.\r\n   \"On June 23-24, 2009, a small swarm of low-frequency earthquakes was recorded at Veniaminof, the last of the calendar year as the network began deteriorating. On the morning of October 19, 2009, a U.S. Coast Guard flight crew flying over Bristol Bay reported 'steady smoke and ash' coming from the center of Veniaminof. Web camera images at the time showed a voluminous, low-level steam plume over the volcano, but no indication of ash.\r\n   \"On November 17, 2009, due to continued station outage, reducing the network to only a single station, AVO issued a VAN downgrading the volcano from Aviation Color Code/Volcano Alert Level GREEN/NORMAL to UNASSIGNED, and delisting it from the inventory of seismically monitored Alaska volcanoes. The volcano would remain at this status through the remainder of 2009.\"","StartYear":2009,"StartMonth":1,"StartDay":8,"StartTime":null,"StartQualifier":7,"StartQualifierUnit":"Days","EndYear":2009,"EndMonth":10,"EndDay":19,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Veniaminof","ParentVolcano":"Veniaminof","VolcanoID":"ak301","ParentVolcanoID":"ak301"},{"ID":801,"Name":"Aniakchak 2009/2","Description":"From McGimsey and others (2014): \"Following several episodes of anomalous seismicity in 2008 (Neal and others, 2011), deep, low-frequency seismic events continued to be recorded at Aniakchak Volcano through the first half of 2009 while the seismic network was still operating. On February 27 and 28, 12 low-frequency events were recorded that had magnitudes of ML 1.0-2.1 and hypocentral depths of about 15-28 km (9.3-17.4 mi), and another sequence of events occurred on March 4 with one locatable low frequency event about 7 km (4.4 mi) depth (Scott Stihler, U.S. Geological Survey, written commun., 2011). Another burst of low-frequency events occurred at Aniakchak on June 3, 2009.\r\n   \"By September 2009, chronic station outages and data interruption prompted AVO to include Aniakchak in the list of four volcanoes considered for downgrading to UNASSIGNED. On November 17, AVO issued a Volcanic Activity Notice and an Information Statement formally declaring that Aniakchak and three other volcanoes: Veniaminof, Fourpeaked, and Korovin were no longer seismically monitored due to seismic station outages, and thus were changed from volcano alert level NORMAL and Aviation Color Code GREEN to UNASSIGNED. Two seismic stations at Aniakchak became operational by December 8, 209, but would again go out in early 2010. The network would eventually become operational again during the summer of 2010.\"","StartYear":2009,"StartMonth":2,"StartDay":27,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2009,"EndMonth":6,"EndDay":3,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":821,"Name":"Okmok 2009/3","Description":"From McGimsey and others (2014): After the 2008 eruption, \"activity at Okmok remained at background levels until the morning of March 2, 2009, when a series of relatively strong, tremor-like events were recorded on the local seismic network. The largest tremor burst occurred at about 21:11-21:18 UTC. These events were recorded on average about once per hour during a 24-hour period, but were not detected on adjacent networks. A clear satellite view on February 28 revealed a 1-pixel thermal anomaly in the caldera near the location of Cone D, on the northeastern floor of the caldera. Clouds obscured satellite view of the area on March 2, and any surface manifestation accompanying the seismic activity went unobserved. In response to this abrupt, anomalous seismicity, AVO upgraded the Aviation Color Code/Volcano Alert Level to YELLOW/ADVISORY on the evening of March 2, 2009. A pilot flying low over the caldera on March 3 made observations and took several photographs. Several of the photographs appear to show an indistinct flowage deposit down the flank of New Cone [Ahmanilix], a 400-m (1,300 ft) high tephra cone (Schaefer and others, 2012) developed inside the caldera at the primary eruption site (see fig. 25 of Neal and others, 2011 for location). A clear satellite view on March 9 revealed an area of broad, but apparently shallow, slope failure on the west-northwest side of New Cone, which partly filled the pair of shallow pits located between the cone and the new lake west of Cone D. Material - likely pumice - also spread out into the lake but had been windblown to the eastern shore. \r\n\"Deformation (uplift) of the caldera floor began in August 2008 following cessation of the eruption. The GPS data from September 1, 2008 to March 1, 2009, show a linear progression of 9 cm of uplift in the center of the caldera (J. Freymueller and T. Fournier, UAFGI, written commun., May 3, 2009, AVO internal log entry 29436). Although seemingly rapid, the uplift was not considered unusual compared to the considerably more rapid inflation pulse that occurred in 2002-03 during a non-eruptive episode (J. Freymueller, UAFGI, written commun., May 3, 2009, AVO internal log 29436). \r\n\"Seismicity remained at low, to near background levels for the next several weeks, and satellite views showed no activity, thus prompting AVO to lower the Aviation Color Code/Volcano Alert Level to GREEN/NORMAL on March 20, 2009. No significant changes or activity occurred for the next 2 months. Then, on May 24-25, 2009, a series of tremor bursts were recorded, including a 15-minute-long high amplitude signal that registered across the entire Okmok network. The activity ceased almost as quickly as it began, and the network returned to near background seismic levels.\r\n\"Activity at Okmok remained at background levels through the remainder of 2009. The only point of interest was that satellite imagery in June compared with earlier imagery revealed extensive erosion of the 2008 eruption features within the caldera (J. Larsen, UAFGI, written commun., 2009, AVO internal log entry). Many of the collapse pits had become filled with erosional debris, the flanks of New Cone became heavily rilled, and the crater floor enlarged as sediment began filling and raising the bottom. The two lakes adjacent to New Cone also increased significantly in size.\"\r\nFrom Neal and others (2014): \"The rapid inflation [during 2009] slowed somewhat by the middle of 2010. In 2011, in inflation at Okmok continued, increasing over recent (2010) rates (5-6 cm over a 12-month period ending in September 2011), but still at a lower rate than was recorded following the 2008 eruption (M. Kaufman, UAFGI, written commun., September 7, 2011). In summary, the inflation at Okmok continues - albeit in pulses - with rates in the 5-7 cm/yr range (J. Freymueller, UAFGI, written commun., September 28, 2013).\"","StartYear":2009,"StartMonth":3,"StartDay":2,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Okmok","ParentVolcano":"Okmok","VolcanoID":"ak206","ParentVolcanoID":"ak206"},{"ID":610,"Name":"Redoubt 2009/3","Description":"From Schaefer (ed), 2012: \"Redoubt Volcano, an ice-covered stratovolcano on the west side of Cook Inlet, erupted in March 2009 after several months of escalating unrest. The 2009 eruption of Redoubt Volcano shares many similarities with eruptions documented most recently at Redoubt in 1966-68 and 1989-90. In each case, the eruptive phase lasted several months, consisted of multiple ash-producing explosions, produced andesitic lava and tephra, removed significant amounts of ice from the summit crater and Drift glacier, generated lahars that inundated the Drift River valley, and culminated with the extrusion of a lava dome in the summit crater. Prior to the 2009 explosive phase of the eruption, precursory seismicity lasted approximately six months with the first weak tremor recorded on September 23, 2008. The first phreatic explosion was recorded on March 15, and the first magmatic explosion occurred seven days later, at 22:34 on March 22. The onset of magmatic explosions was preceded by a strong, shallow swarm of repetitive earthquakes that began about 04:00 on March 20, 2009, less than three days before an explosion. Nineteen major ash-producing explosions generated ash clouds that reached heights between 17,000 ft and 62,000 ft (5.2 and 18.9 km) ASL. During ash fall in Anchorage, the Ted Stevens International Airport was shut down for 20 hours, from ~17:00 on March 28 until 13:00 on March 29. On March 23 and April 4, lahars with flow depths to 10 m in the upper Drift River valley inundated parts of the Drift River Terminal (DRT). The explosive phase ended on April 4 with a dome collapse at 05:58. The April 4 ash cloud reached 50,000 ft (15.2 km) and moved swiftly to the southeast, depositing up to 2 mm of ash fall in Homer, Anchor Point, and Seldovia. At least two and possibly three lava domes grew and were destroyed by explosions prior to the final lava dome extrusion that began after the April 4 event. The final lava dome ceased growth by July 1, 2009, with an estimated volume of 72 Mm3.\"\r\n\r\nWallace and others (2012) calcuate a total Dense Rock Equivalent of about 0.02 cubic meters for tephra fall from the Redoubt 2009 eruption.","StartYear":2009,"StartMonth":3,"StartDay":15,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2009,"EndMonth":7,"EndDay":null,"EndTime":null,"EndQualifier":1,"EndQualifierUnit":"Months","Volcano":"Redoubt","ParentVolcano":"Redoubt","VolcanoID":"ak231","ParentVolcanoID":"ak231"},{"ID":791,"Name":"Sanford 2009/3","Description":"   From McGimsey and others (2014): \"On March 18 and 19, 2009, local Copper River Basin residents observed a large, unusual cloud emanating from the summit of Mount Sanford volcano (figs. 2-4). AVO was alerted on March 19 because the cloud had persisted for more than 24 hours and some residents were concerned that the cloud indicated volcanic activity. The cloud was reported to extend for more than 50 km (30 mi). The plume was visible March 19 on a webcam located at the High Frequency Active Auroral Research Program (HAARP) facility, 29 km (18 mi) north of Glennallen, Alaska, but the view was 'all clear' at Sanford from this camera on March 20. From the vantage point of most residents of the Copper River Basin, this cloud appeared to be a feature unique to Sanford; however, AVO remote sensing specialists examining satellite images of the region reported that this was one of several orographic clouds streaming off the higher mountain peaks in the area. AVO issued an Information Statement on March 20 to report and explain the observations.\"","StartYear":2009,"StartMonth":3,"StartDay":18,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2009,"EndMonth":3,"EndDay":19,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Sanford","ParentVolcano":"Sanford","VolcanoID":"ak242","ParentVolcanoID":"ak242"},{"ID":611,"Name":"Cleveland 2009/6","Description":"From McGimsey and others (2014): \"For the next three months [following the short-lived eruption in January, 2009], no significant activity was reported or observed at Cleveland, and on May 1, 2009, AVO downgraded the Aviation Color Code and Volcano Alert Level to UNASSIGNED. Then, on the morning of June 25, 2009, satellite imagery caught a small eruption occurring that sent an ash plume up to about 15,000 ft (about 4,600 m) and ballistics onto the upper flank snowfields. As with several previous eruptions, air waves generated by the event were registered on seismometers at nearby volcanoes (M. Haney, AVO/USGS, written commun., 2009, AVO internal logs). AVO promptly elevated the Color Code/Alert Level from UNASSIGNED to ORANGE. When observed, the plume was already detached and moving south over the North Pacific. Based on no further reports or evidence of activity over the next several days, AVO lowered the Color Code/Alert Level to YELLOW/ADVISORY on June 27. The volcano remained quiet for the next couple of weeks, and on July 15, the Color Code/Alert Level was downgraded to UNASSIGNED. No activity was observed or reported during the subsequent 2.5 months.\"","StartYear":2009,"StartMonth":6,"StartDay":25,"StartTime":"11:15:00","StartQualifier":2,"StartQualifierUnit":"Hours","EndYear":2009,"EndMonth":6,"EndDay":25,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":612,"Name":"Cleveland 2009/10","Description":"From McGimsey and others (2014): \"On October 2, 2009, another small eruption occurred at Cleveland. Satellite images from 08:11 and 08:25 UTC (00:11 and 00:25 am AKDT) on October 3, 2009, showed a detached ash cloud moving to the northeast away from the volcano. The HYSPLIT particle trajectory model calculated a 6-km-high (20,000 ft) plume originating at about 07:15-07:30 UTC on October 3 (11:15-11:30 pm AKDT). A strong ash signal was indicated from analysis of the satellite data. The cloud was 40 km long (25 mi), 12 km wide (7.5 mi), and 122 km (76 mi) from the volcano at 08:25 UTC (October 3). By 10:00 UTC (02:00 am AKDT on October 3), the cloud was 231 km (144 mi) from the volcano. In response to this activity, AVO upgraded the Aviation Color Code/Volcano Alert Level to ORANGE/WARNING at 02:29 am AKDT (10:29 UTC) on the morning of October 3, 2009.\r\n\"Activity decreased as abruptly as it had started, and on the afternoon of October 5, 2009, the Color Code/Alert Level was downgraded to YELLOW/WATCH. Clear satellite views, particularly on October 15 and 19, showed no further signs of activity, and on October 19, 2009, status of the volcano was downgraded to UNASSIGNED. Cleveland remained quiet almost until the end of 2009. A small, low-level ash plume was emitted on December 12, 2009, but there were no changes to the status for the remainder of 2009.\"","StartYear":2009,"StartMonth":10,"StartDay":2,"StartTime":"23:30:00","StartQualifier":null,"StartQualifierUnit":null,"EndYear":2009,"EndMonth":12,"EndDay":12,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":941,"Name":"Aniakchak 2010/1","Description":"From Neal and others (2014): \"A low-frequency event followed by a short-lived tremor-like signal was recorded January 15, 2010,  on station ANPB. There were no other stations recording data to facilitate further analysis; winters are particularly hard on Aniakchak stations and by January 26, all seismic stations were offline. On July 7, after summer maintenance and repair, two stations (ANPB and ANPK) recorded an approximate 15-minute long swarm. Another brief sequence of low-frequency events was recorded on station ANON on August 7  from about 21:20 to 21:28 UTC. From about 21:28 to 21:35 UTC, a signal resembling tremor occurred, although it also could be interpreted as a series of closely spaced, low-frequency events. This signal was picked up by the other five stations in the Aniakchak network. \r\n\"On October 14 from about 22:29 to 22:39 UTC, another sequence of low-frequency events occurred in the Aniakchak area. Only one event could be located, about 6 km (4 mi) east-northeast of Vent Mountain, the  most prominent intracaldera cone. Another similar although shallower (9.1 km or 5.6 mi), low-frequency sequence also occurred on October 19. This event was located about 2 km (1.2 mi) south-southeast of Vent Mountain with a local magnitude of 0.5.\r\n\"Cluster, low-frequency events occurred on November 5, December 16, and from December 22-24. These small, emergent events may have been related to ice processes in the vicinity of the seismic station (H. Buurman, University of Alaska, written commun., 2010).\"","StartYear":2010,"StartMonth":1,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":901,"Name":"Makushin 2010/2","Description":"From Neal and others (2014): \"Low level seismicity was recorded at Makushin Volcano throughout 2010. At about 7:00 p.m. Alaska Standard Time on February 17, a veteran pilot noted an unusual dark plume over the volcano during exceptionally clear conditions. Later, Guardian Flight paramedic Wayne Boots sent AVO images of strong fumarolic output at the Makushin summit from February 19. AVO reviewed seismic data and saw no change of any significance related to a possible plume. On February 24, a strong vapor plume was visible with satellite imagery but again, no change in seismicity was noted. On March 3, AVO satellite analysts reported slightly elevated temperatures in the vicinity of the summit craters; not an unusual observation for the fumarolically active summit of Makushin.\r\nSeismicity increased slightly with a small swarm on April 7 and again in May. AVO did not elevate the Aviation Color Code or Alert Level for Makushin for either of these slight departures from background.\"","StartYear":2010,"StartMonth":2,"StartDay":17,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2010,"EndMonth":5,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":841,"Name":"Sanford 2010/3","Description":"From Neal and others (2014): \"On March 23, a consulting geologist working in the area reported seeing a 'good size plume' from Sanford on 2 night. A number of Copper River Valley residents shared photographs of Sanford from March 15 when a dramatic looking plume emated from the southern flank and summit of the volcano.\r\n\"A similar cloud was reported on October 20 by Pete Dalton, District Ranger for the National Park Service, stationed at the Gulkana Airport. According to Pete Dalton, the plume rose about 2000 to 3000 ft above the summit. AVO received multiple calls regarding the October 20 plume, which appeared to originate from several points on the near-vertical, rocky southern face of the volcano. A towering vapor cloud emanating from the steep rocky face of this volcano has been reported before (McGimsey and others, 1999) and may be related to rock and ice-fall activity, solar warming of the rock and ice face, or a combination of processes. No features related to volcanic heat sources have been documented on Mount Sanford; however, no comprehensive thermal survey has been done.\"","StartYear":2010,"StartMonth":3,"StartDay":15,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2010,"EndMonth":10,"EndDay":20,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Sanford","ParentVolcano":"Sanford","VolcanoID":"ak242","ParentVolcanoID":"ak242"},{"ID":621,"Name":"Cleveland 2010/5","Description":"From Neal and others (2014): \"A sudden and sustained increase in surface temperature in May prompted AVO to upgrade the Aviation Color Code and Volcano Alert Level from UNASSIGNED to YELLOW/ADVISORY on May 25 [2010]. After consistent thermal anomalies during the last week of May, AVO remote sensors detected a small ash plume on satellite imagery on May 30. The plume was traveling at an estimated altitude of 16,000 ft ASL and drifting south. \r\nASTER acquired a mostly clear view of Cleveland on June 1. Recent dark flowage deposits are visible on the eastern flank and tephra-fall deposits blanket a swath to the southwestern coastline. The summit crater was hidden by a white vapor cloud.\r\nFollowing the impulsive ash event on May 30, AVO ceased to detect consistently elevated surface temperatures and, without additional observations of activity, AVO returned the volcano to UNASSIGNED on June 11.","StartYear":2010,"StartMonth":5,"StartDay":30,"StartTime":"19:56:00","StartQualifier":null,"StartQualifierUnit":null,"EndYear":2010,"EndMonth":5,"EndDay":30,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":891,"Name":"Westdahl 2010/7","Description":"From Neal and others (2014): \"In late July, AVO seismologists noted a marked increase in lower crustal seismicity at Westdahl. Most of the seismicity was long period in character however some volcano-tectonic events also were recorded. \r\nDeep (\u003e10 km or \u003e6.2 mi), low frequency events located with the Westdahl seismograph network tend to cluster in an area northwest of the volcano's summit. Past analysis of InSAR results for Westdahl by Lu and others (2003) suggests a shallow magma reservoir beneath the volcano. Continued inflation of the volcano is consistent with ongoing accumulation of melt at shallow levels. Such ascent of magma from depth may explain the 2010 seismicity at Westdahl.\"","StartYear":2010,"StartMonth":7,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Westdahl","ParentVolcano":"Westdahl","VolcanoID":"ak322","ParentVolcanoID":"ak322"},{"ID":961,"Name":"Aniakchak 2010/8","Description":"From McGimsey and others (2014): \"In late August 2011, AVO was alerted by Troy Hamon, Chief of Resource Management, Katmai National Park, that the larger of two maar crater lakes on the caldera floor of Aniakchak Volcano had recently drained, leaving a gaping notch in the crater rim. The flood had ravaged the downstream drainage and alluvial fan as well as the upper reaches of the Aniakchak River, which drains Surprise Lake and the eastern caldera floor through The Gates. During September 8-9, 2011, authors Tina Neal and Game McGimsey, accompanied by Troy Hamon (on September 8), visited the site to document and study the activity.\r\n\"Aniakchak caldera formed about 3,600 years ago in a colossal eruption (Neal and others, 2001). Subsequent eruptive activity has occurred from many intracaldera vents, including eruptions that formed two maar craters, subsequently filling with water, that are situated on the southeastern caldera floor between the central Vent Mountain cone and the sheer inner east caldera wall. The larger maar is about 450 m (1,476 ft) by 515 m (1,690 ft), as measured rim to rim in Google EarthTM imagery (fig. 3); the smaller maar is 170 m (558 ft) in diameter at the rim. The maars formed subsequent to the draining of a caldera-wide lake, at least 1,000 years before present (BP), but they may be much younger, perhaps less than 400 years old.\r\n\"Geological investigations in 1992 documented that a low point on the maar rim was about 10-15 m (33-49 ft) above the lake surface, although higher strand lines were visible in the deposits surrounding the maar, one of which was located nearly at the low point (Neal and others, 2001). On the outboard flank of the maar-rim low-point, a seep - piping through the maar crater wall deposits to the lake - occurred near the base of the flank and formed the headwater for the stream that courses between a prominent lava flow from Vent Mountain and the colluvial slopes extending out from the eastern caldera wall. This stream flows about 1.7 km (1 mi) northward from its source at the maar to the Aniakchak River immediately inboard of The Gates, a prominent notch in the caldera wall through which the river drains the entire caldera.\r\n\"The maar breakout flood scoured and excavated the channel and banks of the stream north of the maar, cutting deeply into the colluvial slopes on the eastern side of the drainage. The previously well-vegetated alluvial fan near The Gates was entirely covered by flood deposits up to 1.5 m (4.9 ft) thick. Clumps of vegetation, up to about 1 m (3.3 ft) in length, were strewn on and within the deposit. The Aniakchak River was pressed even more tightly against the northern wall opposite the fan, causing some bank erosion, and the downstream river channel, sand bars, and banks were noticeably disrupted for more than 20 km (12.4 mi) beyond The Gates. The area of the breach on the maar rim was dramatically altered as downcutting progressed until a new base level was established. Discharge through the outflow at the northern end of the maar now approximates inflow at the southern end (primarily at the waterfall.\r\n\"Field measurements and observations indicate that the maar lake level declined 4.65 m (15.3 ft) from its recent high stand (determined from photographs taken July 18, 2010), as well as measurements made in the field in September 2011); this high stand was below the low-point on the northern rim where the breach occurred. The volume of water lost was at least 645,000 m3 (844,000 cubic yards), but this represents a minimum volume because there is no way of knowing how much additional water flooded into the maar immediately prior to initiation of the breakout flooding.\r\n\"Based on analysis of photographs, weather data, and observations from a local guide, the maar flood likely occurred between late July and late September 2010. Evidence of recent flooding on the southern floor and wall of the caldera, which drain into the maar, suggests that the maar flood was likely caused by the rapid and voluminous influx of water into the maar lake during a period of unusually heavy rainfall. The lake level rose rapidly and the low point on the maar rim may have been reached and spilled over. The increased hydraulic head may have simultaneously initiated failure of the crater wall at that location where groundwater seepage and possibly piping within the mantling deposit was occurring. The heavy precipitation may have further increased saturation of the deposit. Once the breach began, by either rapid downcutting, or structural failure of the wall, or both, rapid release of water occurred, resulting in a short-lived but massive flood down the drainage to - and then down - the Aniakchak River.\"","StartYear":2010,"StartMonth":8,"StartDay":null,"StartTime":null,"StartQualifier":2,"StartQualifierUnit":"Months","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":622,"Name":"Cleveland 2010/9","Description":"From Neal and others (2014): \"On 18 July, 2010, a magnitude 6.6 main-shock occurred 9 km (5.6 mi) northeast of the summit of Mount Cleveland. AVO field personnel on Umnak Island reported that buildings shook and fuel barrels rolled back and forth several inches (M. Kaufman, UAFGI/AVO, written commun., 2010). The earthquake also was felt in Unalaska/Dutch Harbor, although residents described the shaking as 'light' or 'weak'. \r\n\"This event triggered a subsequent earthquake cluster of more than 1,800 aftershocks greater than magnitude 2.5 and about 110 magnitude 4.0 or greater events. According to analysis by AEIC, a M 4.0 foreshock had occurred on July 17 at 14:44 UTC. Earthquakes during this time period were restricted to an approximately 25-km-wide (15-mi) area extending from eastern Chuginadak Island to the edge of the Aleutian platform about 60 km (37 mi) southeast. The largest aftershock of magnitude 6.0 occurred on July 18.\r\n\"AEIC analysis of fault plane solutions for the large events of this series determined that the larger earthquakes were located on north-northwest-trending normal faults. This was the largest event to occur in the region since the magnitude 6.5 earthquake on October 13, 2009. Similar sized earthquakes occurred in the same area on May 10, 2006, and December 26, 2007. AEIC located nearly 3,200 aftershocks through end of July, including about 60 aftershocks with magnitudes 4.0 or greater.\r\n\"The earthquake had no clear impact on Cleveland volcano; however, elevated surface temperatures reappeared at the summit throughout July and August. Based on this, AVO upgraded the Aviation Color Code and Volcano Alert Level to YELLOW/ADVISORY on August 26. On August 26, 29, and 31, pilots from Alaska Airlines flying the Anchorage to Adak route reported no volcanic ash from Mount Cleveland. Thermal anomalies continued into September but did not intensify; on September 10, the Aviation Color Code and Alert Level were downgraded to UNASSIGNED.\r\n\"On September 12, the Anchorage VAAC reported a possible weak ash signal in satellite data. If this was an eruption cloud, the plume rose only a few thousand feet above the volcano's summit and disspated quickly. A one-time VAA was released but no SIGMET was issued. AVO upgraded the Aviation Color Code and Volcano Alert Level to YELLOW/ADVISORY. Observations from a pilot in the area of Mount Cleveland reported that no ash was visible, at least below 2,900 ft. Clear satellite views continued to show elevated surface temperatures in the summit crater but no ash plumes.\r\n\"Clouds frequently prevented remote viewing of the volcano but during periods of clear conditions, thermal anomalies were noted intermittently through the end of the year. AVO maintained Cleveland at Aviation Color Code and Volcano Alert Level YELLOW/ADVISORY. There were no reports of ash or other activity except for an anomalous infrasound signal that was received on September 15 at 00:24 and 00:30 UTC (Steve McNutt, UAFGI/AVO, written commun., 2010) and may have represented a small explosion from the volcano.\"\r\nWeak thermal anomalies were visible on January 1, 11, and 16 [2011], and the weather remained cloudy for the remainder of the month.\r\nIn February, a weak thermal anomaly was observed on the first. On the 9th, a pilot overflew Cleveland and reported minor, repetetive steam emissions rising hundreds of feet above the summit. The snow on the flanks was pristine, with no indication of recent ash emissions. Steam emissions are common at Cleveland and do not indicate an increased level of unrest.\r\nIn March, a weak thermal anomaly was observed on March 2, 3, and 11. A cloud-free view of the volcano on March 23 showed no unusual activity. On March 31, 2011, AVO lowered the volcano alert to UNASSIGNED and the aviation color code to UNASSIGNED, on the basis of a lack of confirmed eruptive activity over the past several months.","StartYear":2010,"StartMonth":9,"StartDay":12,"StartTime":null,"StartQualifier":1,"StartQualifierUnit":"Days","EndYear":2011,"EndMonth":3,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":831,"Name":"Wrangell 2010/11","Description":"From Neal and others (2014): \"No eruptive activity or significant unrest occurred at Wrangell in 2010. However, AVO received an interesting new image of the summit region as well as a report of possible vapor emission from the summit area.\r\n\"In May 2010, a single lidar swath over the summit of Wrangell was flown by UAFGI glaciologists Paul Claus and Chris Larsen. The resulting processed image depicts the topography of North Crater, a long-known fumarolic source on the northwestern rim of the ice-filled summit caldera. The characteristic higher northern and lower southeastern rim of the crater is clear in a cross-section of the lidar-derived topography. Within North Crater, there are several secondary depressions including a complex, kidney-bean shaped pit about 20 m (65 ft) deep and 200 m (660 ft) across, located in the center of the crater. This result is broadly consistent with previously recorded surveys of North Crater using photogrammetric techniques (Benson and others, 2007).\r\n\"In early November, a long-time resident from the Copper River valley called AVO to report 'more activity at the Mount Wrangell summit than he had ever seen before.' He sent AVO several images of the volcano taken on November 2. The observer reported that when the activity in question began, there had been no weather clouds in the area. He noted about ten 'bursts' from the summit and said this was unusual compared to the typical steady emissions often seen above the volcano. AVO reviewed available seismic and satellite data and, finding no evidence of volcanic signals, concluded that the phenomenon was most likely weather related.\"","StartYear":2010,"StartMonth":11,"StartDay":2,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Wrangell","ParentVolcano":"Wrangell","VolcanoID":"ak326","ParentVolcanoID":"ak326"},{"ID":692,"Name":"Cleveland 2011/7","Description":"From McGimsey and others (2014): \"On July 20, AVO upgraded the Aviation Color Code/Volcano Alert Level from UNASSIGNED to YELLOW/ADVISORY after thermal anomalies were observed in satellite imagery during routine satellite monitoring on July 16-17. On August 2, the Aviation Color Code/Volcano Alert Level was upgraded to ORANGE/WATCH based on persistent thermal anomalies detected at the volcano's summit as well as satellite evidence of new lava in the summit crater on July 31.\r\n\"In 2011, Cleveland's summit crater was about 200-225 m (660-740 ft) wide at the rim; its depth varies through time with the impacts of eruptive activity, but can be as much as 80-100 m (260-330 ft). Extrusion of lava in the summit crater presumably began around the time of the onset of persistent thermal anomalies, during July 16-17; a new dome in late July 2011 was approximately 40 m (130 ft) across. Satellite images of the summit on August 3 showed the dome to be approximately 50 m (160 ft) across and no more than 20 m (65 ft) above the summit crater floor. The dome may have grown to 60 m (200 ft) across by August 6 implying an approximate lava volume of 115,000 cubic meters (150,420 cubic yards) or 7 percent of the crater's total volume of approximately 1,6 million cubic meters (2,1 million cubic yards). Satellite imagery showed no significant new tephra deposits indicating that activity from mid-July into early August was primarily extrusive. This was consistent with an August 9 WorldView-1 satellite image of Cleveland's summit showing steaming, light-colored alteration deep inside the summit crater around the new lava dome, and with oblique aerial photographs taken on August 8 by NOAA scientists. \r\n\"On August 10, AVO received a mariners report from the National Weather Service (NWS) Ocean Prediction Center of possible ash floating on the sea surface approximately 25 km (13,5 nmi) north-northwest of Cleveland. The same source reported the absence of any floating ash earlier in the day at about 30 km (16 nmi) north of the volcano. No ash clouds were detected in satellite data during the times of the these reports. Analysis of satellite data indicated that during August 6-13, the lava dome grew only slightly larger than detected in the previous image acquired August 6. Although it is possible that these accounts of drifting ash are valid, AVO was unable to confirm them.\r\n\"On August 30, AVO downgraded Cleveland's Aviation Color Code/Volcano Alert Level from ORANGE/WATCH to YELLOW/ADVISORY, based on the absence of distinct thermal signals at the summit. Satellite observations on September 6 indicated that the lava dome had grown to about 120 m (390 ft) in diameter and consistently elevated surface temperatures were again observed. As a result of these observations, AVO upgraded Cleveland to Aviation Color Code/Volcano Alert Level ORANGE/WATCH. By this time, the lava dome essentially filled the summit crater. \r\n\"TerraSAR-X satellite radar images from the German Remote Sensing Data Center (DFD) and the German Aerospace Center (DLR), acquired over Cleveland volcano from August to November 2011, provided an image time series showing the partial growth of the 2011 lava dome in the summit crater.\r\n\"The lava dome continued to grow through late September, expanding in diameter from approximately 120 m (390 ft) on September 6 to approximately 168 m (550 ft) by September 20, and reaching a height approximately 15-20 m (50-60 ft) below the crater rim by September 26. Additional growth of the lava dome past October 20 was minor.\r\n\"Extrusion of lava either slowed or ceased between October 1 and October 5. Satellite data from October 9 indicated that the central portion of the lava dome became slightly depressed, indicating minor deflation of th edome. Subsidence of the dome continued into late October.\r\n\"AVO downgraded Cleveland's Aviation Color Code/Volcano Alert Level from ORANGE/WATCH to YELLOW/ADVISORY on November 3 based on the absence of consistent thermal anomalies in satellite images and apparent cessation of lava effusion after October 9.\r\n\"On November 10, satellite images showed that a small secondary dome had emerged atop the center of the semi-deflated lava dome. The diameter of this new dome was approximately 15-20 m (50-65 ft) and it likely began to grown on or before November 2. The original dome remained unchanged in size.\r\n\"Lava within the summit crater remained mostly unchanged from November 10 to November 24. A satellite image from November 25 showed that the small secondary dome had subsided into a broad blocky, hummocky depression approximately 70 m (230 ft) in diameter and the overall dome had subsided approximately 30 - 35 m (100-115 ft) from its maximum elevation in early October. The dome continued to subside into early December, and by December 7, nearly the entire extrusive feature had collapsed into the conduit and its surface was approaching the pre-August crater-floor elevation.\r\n\"On December 29 at approximately 04:12:07 AKST (13:12:07 UTC), an explosion from Cleveland produced a small ash cloud that rose to approximately 3.5 km(11,500 ft) ASL. The ash cloud drifted to the east and over the southwestern tip of Umnak Island. The eruption triggered two operational ash alarms used by AVO. The first alarm was triggered at approximately 05:33 AKST (14:33 UTC) indicating likely ash signatures in NOAA's AVHRR satellite image n19.11363.1402. A NOAA-NESDIS ash cloud alarm was triggered at approximately 05:34 AKST (14:34 UTC) from the same AVHRR satellite image. Calculations based on the satellite data and local meterologic conditions indicated a maximum ash cloud height of 3.5 km (11,500 ft) ASL, with a mean effective ash particle radius of 5.06 microns (1,99 x 10^-4 in.), a total mass of 0.84 kt (925 tons), and a total area of 173 square km (66.8 square miles) (M. Pavolonis, written commun., December 29, 2011). \r\n\"In response to the ash cloud, AVO upgraded the Aviation Color Code/Volcano Alert Level from YELLOW/ADVISORY to ORANGE/WATCH at 07:55 ASKT (16:55 UTC) on December 29, 2011.\r\n\"Infrasound signals from the December 29 explosion were first detected on seismic stations and infrasound arrays deployed at Okmok volcano, located approximately 139 km (90 mi) northeast of Cleveland on Umnak Island. Infrasonic waves are sound waves that span a frequency range from below 20 Hz (the lower limit of human hearing) to 0.001 Hz. Infrasound signals are recorded at seismic stations by the infrasound airwaves coupling with the ground at seismic station(s) and mechanically vibrating the ground in which the seismometer sits. The recorded seismic signal is known as a ground-coupled airwave produced by a volcanic explosion or eruption. Based on the speed of sound in Earth's atmosphere and the distance between seismic station OKWE and the summit of Cleveland the origin time of the explosion was calculated at approximately 04:12:04 AKDT (13:12:07 UTC) (Matt Haney, David Fee, and Silvio de Angelis, UAFGI, written commun., December 29, 2011).\r\n\"AVO downgraded the Aviation Color Code/Volcano Alert Level for Cleveland volcano from ORANGE/WATCH to YELLOW/ADVISORY at 13:57 AKST (22:57 UTC) on December 29 following no additional reports of eruptive activity occurring at the volcano. Cleveland remained at Aviation Color Code/Volcano Alert Level YELLOW/ADVISORY throughout the remainder of 2011.\r\n\"A review of the infrasound data prior to the December 29 explosion revealed several small explosive eruptions from Cleveland volcano on December 25. The first occurred at approximately 03:13 AKST (12:13 UTC) and had an infrasound amplitude of approximately one-half the December 29 event. The second eruption occurred on December 25 at approximately 06:32 AKST (15:32 UTC).\r\n\"A small ash cloud was retrospectively detected in satellite imagery for the December 25 event. The eruption cloud was very minor, did not have a large ash signal at the image's collection time of 06:32 AKST (15:32 UTC), and was only weakly visible in a thermal infrared image. The cloud had dissipated by the time the next image was acquired at 06:46 AKST (15:46 UTC).\r\n\"Satellite data from December 26 displayed evidence of ejected blocks that had rolled down the upper northern and western flanks of the volcano, some as far as about 1.5 km (5,000 ft) from the crater's rim. There was no indication of fresh ash deposits on the volcano's upper northern and western flanks.\"\r\nFrom Herrick and others (2014): \"On January 30, a new lobe of lava about 40 m (130 ft) across was detected at the bottom of the summit crater. On January 31, the Aviation Color Code and Volcano Alert Level was upgraded to ORANGE/WATCH due to the presence of this small lava flow and the increased potential for explosive dome destruction.\r\n\"On February 3, satellite data showed no significant change within the summit crater. By February 7, the dome had grown to about 50 m (160 ft) across and 1 week later, 60 m (200 ft). On February 22, additional new lava had broken the surface of the dome producing a 20-m-diameter (66-ft) lobe atop the existing lava pad. Evidence of continued effusion was reported through the end of February and slightly elevated temperatures were reported during clear conditions.\r\n\"Three explosions occurred from the Cleveland summit crater in the first 2 weeks of March; the March 8 explosion produced a small ash cloud that dissipated quickly. Details of how much of the new lava dome was destroyed in each explosion are unknown, but by March 11, it was entirely removed. Cloudy conditions prevailed and ash emissions that may have been produced after March 8 went unnoticed. On March 23, the Aviation Color Code and Volcano Alert Level was downgraded to YELLOW/ADVISORY based on the lack of evidence of renewed lava effusion.\r\n\"On March 26, a new lava flow about 70 m (230 ft) across was detected within the crater. On March 28, the Aviation Color Code and Volcano Alert Level was upgraded to ORANGE/WATCH. By April 4, the dome was gone, likely removed in an explosion at about 09:12 UTC on April 4. Subsequent satellite images showed that large blocks, 15-20 m (50-65 ft) across, littered the crater floor. Four additional explosions occurred between April 7 and April 19 during a period of frequently elevated temperatures detected in satellite images. No unequivocal ash clouds were detected following each event; however, weather and satellite overpass timing could have played a role. The AVO Web camera was not functioning during this time.\r\n\"Elevated surface temperatures persisted through April and into May. By April 25, a new dome had appeared in the crater, only to be destroyed sometime before April 29. An ambiguous seismic event had been recorded by the Makushin network at 16:14 UTC on April 29. It may have been related to the dome’s demise, but this remains inconclusive (M. Haney, USGS/AVO, written commun., November 2013). On May 3, the third detected lava flow of 2012 was observed in the crater forming a dome about 25 m (82 ft) in diameter.\r\n\"Explosions occurred on May 4 and 5, but no ash cloud or strong thermal signal was noted for either event. Satellite observations on May 6 showed that the May 3 lava dome was gone, presumably destroyed during the May 4-5 explosions. After 3 weeks with no further explosions and only rare instances of elevated surface temperature, the Aviation Color Code and Volcano Alert Level was downgraded to YELLOW/ADVISORY on May 30. An AVO staff member flying near Cleveland noted white steam rising from the crater.\r\n\"Cleveland remained at YELLOW/ADVISORY despite the detection of another explosion by infrasound on June 4. Only minor tephra and possibly flowage deposits were noted on a June 9 satellite image. On June 19, an explosion produced an ash cloud seen by a pilot, and the cloud also was captured on the AVO Web camera and detected by infrasound. The pilot estimated the cloud height to be 35,000 ft (11 km) ASL. Following detection of the explosion and confirmation of a high ash cloud, AVO upgraded the Aviation Color Code and Volcano Alert Level to ORANGE/WATCH.\r\n\"Several more explosions occurred in late June, July, August, and November; all were detected either on infrasound networks or distant seismic stations. Three of these produced small ash clouds detected by satellite images and one by the AVO Web camera. Satellite observations of the volcano documented minor changes in the summit crater but no additional, intact lava flows were noted through the end of 2012.\"\r\nFrom Dixon and others (2015): \"Early in 2013, a faint white steam cloud emanating from the summit crater was occasionally seen in satellite images. On January 30, 2013, after more than a week of consistently elevated temperatures in AVHRR images, satellite observations indicated a new lava flow inside the summit crater (table 8 in original text). Extrusion began sometime after January 7, when clear satellite images showed no lava in the crater, and before the January 30 satellite image showing a new lava flow. The round dome-like feature was about 100 m across. Significantly elevated temperatures continued in satellite images, visible even in fairly cloudy conditions. By February 9, a second lava extrusion 25 m (82 ft) across was perched across the late January dome. After learning of the existence of new lava in the summit crater, AVO upgraded the Aviation Color Code and Volcano Alert Level on February 6 to ORANGE/WATCH. AVO downgraded to YELLOW/ADVISORY on March 8 after no further escalation of activity.\"","StartYear":2011,"StartMonth":7,"StartDay":16,"StartTime":null,"StartQualifier":7,"StartQualifierUnit":"Days","EndYear":2013,"EndMonth":1,"EndDay":null,"EndTime":null,"EndQualifier":1,"EndQualifierUnit":"Months","Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":703,"Name":"Iliamna 2011/12","Description":"From Herrick and others (2012): \"From January 15 through 17, AVO detected a swarm of volcanic-tectonic (VT) events with the largest event in the sequence being an M2.7 earthquake on January 17; subsequent analysis (H. Buurman, UAFGI, written commun., 2014) places the beginning of the swarm as early as December 22, 2011. On January 27, a pilot called AVO to inquire about webicorder signals displayed on AEC (Alaska Earthquake Center, formerly AEIC, the Alaska Earthquake Information Center) and AVO Web sites. Anticipating additional questions about elevated seismicity at Iliamna, AVO posted explanatory information on the public-access webicorder plot.\r\n\"On March 7, AVO received a telephone call from Dennis Anderson, a photographer from Diamond Ridge above Homer, Alaska. Anderson reported observations of avalanche activity and appearance of new crevasses on the Red Glacier of Iliamna. Public attention resulted in local media calls to AVO and several news stories on the avalanche and increase in seismicity. On March 8, the largest events of the unrest sequence were recorded (M2.96 and M3.01). On March 9, based on the sustained increase in seismicity, AVO upgraded the Aviation Color Code and Volcano Alert Level for Iliamna to YELLOW/ADVISORY. Following the upgrade of Color Code and Alert Level, AVO increased the frequency of seismic checks to once every 6 hours.\r\n\"Examination of photographs from Anderson and satellite images from early March showed clear evidence of avalanching of debris on the upper Red Glacier. Photographs from March 12 showed a vapor plume, 2-4 km (1-2.5 mi) above the crater, drifting north from the summit area. AVO received no reports of increased or anomalous sulfur smell.\r\n\"On March 14, a fumarolic plume was visible on satellite images that drifted north-northwest from the summit; the length and prominence of this cloud-feature was unusual for Iliamna. Based on the appearance of this plume in mid-infrared images, it is possible that the feature was a predominantly water-rich meteorological cloud influenced by a strong Iliamna fumarolic plume.\r\n\"In mid-March, a Web camera (AnnaCam) managed by Hilcorp on a platform in the middle of Cook Inlet was repositioned to allow for visibility of both Iliamna and Redoubt within the same field of view. At the same time, AVO installed a new Web camera pointed at Iliamna (station NNL) on the Kenai Peninsula.\r\n\"AVO seismologists determined that the 2012 earthquake sequence was occurring just south of the summit at 0-4 km (1-2.5 mi) depth. The swarm appeared similar to activity in 1996 (Roman and others, 2004), although the 2012 swarm also had low frequency earthquakes, which were not present in 1996 (H. Buurman, UAFGI, written commun., 2014).\r\n\"A gas measurement flight to Iliamna on March 17 noted levels of carbon-dioxide (CO2) and SO2 at similar values as in 1996 (C. Werner, USGS, written commun., 2012). AVO observers on this flight noted visibly disturbed ice in the area of the upper Red Glacier. Close-up views of the main fumarolic field revealed robust steam- and gas-plumes with possible jetting from some sources. The high southern flank fumarolic field also was more active than usual. Several possible new vents were noted high on the eastern flank that later in the year appeared less active. Minor, recent icefalls also were noted on the western flank.\r\n\"Observations from the gas flight verified that the upper Red Glacier descending Iliamna's eastern flank had undergone a surge in early 2012. This fast creep (or slow slide) event was not a true avalanche, but it was sourced in the same area as large avalanches of the recent past (Huggel and others, 2007). At the time of the observations, it was unclear if the surge was related to changes in the volcano, such as the increase in seismicity, associated increases in heat and gas flux, or just a result of heavy snowfall during the winter of 2011-2012.\r\n\"Into late March, distinctive plumes continued to appear in mid-infrared satellite images. On March 21, sulfur odors were reported by a pilot about 24 km (15 mi) west of Iliamna. Web camera images showed occasional plumes from the summit fumarole fields and above background seismicity persisted through the year's end. Possible thermal anomalies in satellite images were detected on a number of occasions during the year; it remains uncertain if these were a clear departure from background thermal conditions.\r\n\"A second gas flight to Iliamna on June 20 measured SO2, hydrogen sulfide (H2S), and CO2 emissions similar to the March 17 flight when measurements were considered elevated over background and were comparable to the highest measurements from the episode of unrest in 1996. A third flight on August 13 determined that volcanic gas emission continued at elevated levels. Less robust visible vapor plumes suggested a possible decrease in activity, but relatively dry and warm atmospheric conditions may have played a role in the apparent change.\r\n\"On August 21, a citizen called AVO to report a plume rising from Iliamna. Conditions were clear that day and the mountain was backlit. The observer called it an 'uncommon plume' that billowed from the summit with more vigor than typically noted. Later that month (August 27), another observer noted a sulfur odor at Anchor Point on the Kenai Peninsula. Back trajectories from a HYSPLIT model indicated that a gaseous plume from Iliamna would have drifted over Anchor Point at that time, suggesting Iliamna was a likely source. Problems with the seismic network led to data drops and challenges in tracking seismicity in the late summer. When data flow resumed in late September and AVO determined that elevated seismicity at Iliamna had continued.\r\n\"A photograph was taken by a resident on October 13 that showed a flow feature on the southeastern flank of Iliamna. A review of seismic records showed that a possible landslide signal had been recorded at 8:16 p.m. AKDT on October 12 (04:16 UTC October 1), consistent with the apparent flowage deposit captured in the photograph. The dimensions of the avalanche were determined on October 22 with the help of satellite images. At the widest part, the feature was 2,800 x 200 m (1.7 x 0.1 mi). The landslide had originated near the existing fumarolic area high on the southeastern flank just below the summit. Some small melt slides had been visible in that area several days earlier.\r\n\"Elevated seismicity continued through October and November with hypocenters roughly coincident with the 1996 activity. Two bursts of low-frequency seismicity occurred on November 24. Based on the continued levels of seismicity, AVO maintained Aviation Color Code and Volcano Alert Level YELLOW/ADVISORY into 2013. Seismicity and gas measurements during the 2012 unrest are likely explained by a magmatic intrusion to shallow levels below the volcano (Prejean and others, 2012.)\"","StartYear":2011,"StartMonth":12,"StartDay":22,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":693,"Name":"Kanaga 2012/2","Description":"From Herrick and others (2014): \"An increase in seismic activity at Kanaga was first noted on February 18 during a routine seismic check by AVO seismologist S. Stihler, who reported a tremor-like event (interpreted as a possible explosion) followed by smaller events over the next hour. A possible correlative airwave occurred on the Adak seismic station 40 km (25 mi) northeast of Kanaga about 2 minutes after the tremor event (M. Haney, USGS/AVO, written commun., 2012). Ten minutes after the tremor event, a faint ash signal in satellite images may have been a small ash cloud from Kanaga, drifting to the east at an altitude of about 6 km (19,700 ft) ASL. Based on these observations, AVO upgraded the Aviation Color Code and Volcano Alert Level to YELLOW/ADVISORY. Additional analysis of the seismic signal, 'reduced displacements,' showed relatively small values, consistent with hydrothermal or possibly phreatic activity (S. McNutt, UAFGI, written commun., 2012).\r\n\"Adak resident M. Tillion contacted AVO by telephone on February 19 to share photographs and observations of Kanaga on the day after the possible explosion at about 12:26 Adak time or 10:26 UTC. From the White Alice site, west of the community of Adak, a resident noted an acrid odor that caused throat irritation. Kanaga volcano, 37 km (23 mi) northwest of Adak, was steaming strongly from the summit; M. Tillion thought that the plume may have contained some ash but further analysis suggests these were just shadowed clouds. There was, however, evidence of tephra or flowage deposits on the eastern flank extending down from the summit area.\r\n\"Cloudy conditions prevented any direct observations throughout much of February. Slightly elevated surface temperatures at the summit were noted in satellite images on February 21. On February 23, four bursts of tremor-like events were recorded on the Kanaga network. Satellite images from February 26 showed that the summit crater was clear with no evidence of ongoing eruptive activity. Seismicity remained low and on March 2, AVO downgraded the Aviation Color Code and Volcano Alert Level to GREEN/NORMAL, where it remained for the rest of the year.\r\n\"Retrospectively, the combination of satellite images, aerial photographs, and field inspection demonstrated that a brief explosive event from Kanaga's summit had indeed occurred, modifying the summit crater and producing a very small tephra fall deposit. A March 5 satellite radar image clearly showed a new open fissure along the southern rim of the summit crater. The feature was about 600 m (1,970 ft) in length and continued a short distance down the upper western flank of the volcano. In places, the fissure was 15 m (50 ft) wide and white clouds of vapor issued from several points along the fissure. An additional fumarolic cloud issued from the 15-m-diameter (50-ft), circular hole in the bottom of the crater. On March 9, nearly 3 weeks after the explosion signal, no ejecta or ash fall deposits were noted in satellite images, however, additional snowfall and reworking on the steep flanks likely would have obscured any primary deposits. Given the transient nature of the event, the limited tephra fall, and residual steaming fissure, AVO concluded that this event was a sudden phreatic explosion originating in the shallow, hydrothermally active summit region of Kanaga. The orientation and location of the feature has no clear relationship to the 1993-1995 eruptive vent complex that involved effusion of lava and ash from both the summit crater and a fissure system on the upper eastern flank of the volcano (Neal and others, 1995; Waythomas and others, 2002).\r\n\"Notable plumes of white vapor from Kanaga's summit were seen throughout the spring by ship and airborne observers as well as Adak residents. Ship-based observers on April 1 suggested that three distinct locations along the fissure were producing the most intense clouds. At least one satellite image on April 1 showed a possible plume from the summit. Bursts of seismicity were noted in mid- and late April. The seismic record was hampered by periods of noise and scattered data outages in late spring and early summer.\r\n\"An AVO crew working via helicopter on the Kanaga seismic network in mid-June was able to describe the fissure and apparently new ash on the northern and eastern flanks; they were unable to land and inspect the volcano's summit area, however, due to high winds. Steam was steadily rising from the summit fissure. On June 20, a faint sulfur odor was detected at the KINC seismic station located 2 km (1 mi) to the east of the volcano summit; our limited experience on the volcano makes it difficult to know how atypical this observation is from normal conditions. The team noted traces of what appeared to them to be recent ash on the northern flank down to an elevation of about 250 m (820 ft) ASL.\r\n\"Aerial photographs by Roger Clifford in both summer and fall provided excellent views of the summit fissure. Figure 29 shows a summer image of the nearly snow-free Kanaga cone; the fissure can be seen wrapping around and just outboard of the summit crater rim. The maximum opening across the fissure is about 15 m (50 ft) and white vapor issues from several point sources within the fissure. In November, Roger Clifford captured the western extent of the fissure where it crosses the summit and extends about 100 m (330 ft) down the western flank.\r\n\"Brief episodes of elevated seismicity occurred during the rest of the year at Kanaga. On June 27, unusual, emergent seismic events were detected on records from the northern seismic stations of the Kanaga network. Periods of tremor also were noted. The significance of this seismicity with respect to the summit fissure or ongoing activity at Kanaga is unknown.\r\n\"Satellite and seismic data from before February 18 was further analyzed to look for any changes prior to the explosion and opening of the summit fissure. A satellite image from January14, 2012, showed no structure in the area later cut by the fissure, although the southern rim was bare and lightly steaming. In October 2011, an unusual series of low frequency earthquakes had been noted, but any relationship of this to the 2012 activity remains unclear.\r\n\"In response to this event, AVO established automated PUFF runs to simulate ash cloud trajectories in the event of a magmatic eruption, increased the frequency of daily satellite checks, and attempted limited field verification of events in conjunction with seismic network maintenance.\"","StartYear":2012,"StartMonth":2,"StartDay":18,"StartTime":"06:23:00","StartQualifier":null,"StartQualifierUnit":null,"EndYear":2012,"EndMonth":2,"EndDay":18,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kanaga","ParentVolcano":"Kanaga","VolcanoID":"ak144","ParentVolcanoID":"ak144"},{"ID":911,"Name":"Wrangell 2012/3","Description":"From Herrick and others (2014): \"On March 11 [2012], observers in Glennallen noted 'puffs of steam' and called the State of Alaska Department of Homeland Security and Emergency Management office with their concerns. AVO was also contacted and analysts were able to see small plumes above known fumaroles in satellite images.\r\n\"On March 20, a citizen noticed unusually rigorous steaming at Wrangell while driving towards to volcano from Valdez. Steam rose from the summit as well as a location on the southwestern flank at about 3,000 m (10,000 ft) ASL and the citizen described the volcano as looking like 'a pressure cooker shot through with nails'. There also were calls to the observatory on June 21 due to concerns about substantial plumes visible from various vantage points in the Copper River basin. No other evidence of significant volcanic unrest was detected, thus AVO concluded these events were likely generated by normal fumarolic activity. No further response activities were required.\"","StartYear":2012,"StartMonth":3,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Wrangell","ParentVolcano":"Wrangell","VolcanoID":"ak326","ParentVolcanoID":"ak326"},{"ID":931,"Name":"Martin 2012/4","Description":"From Herrick and others (2014): \"During 2012, in addition to reports of strong fumarolic activity, the AVO seismic network recorded bursts of elevated seismicity, similar to episodes seen in recent years (Dixon and Power, 2009; O'Brien and others, 2012). The Aviation Color Code and Volcano Alert Level at Martin remained GREEN/NORMAL.\r\n\"In mid-April, AVO received three emails regarding activity at Martin. Observers in the area of Lower Ugashik Lake about 120 km (75 mi) to the southwest noted a plume that was larger than any that had been seen in more than 50 years in the area. Another observation from an overflight reported a strong sulfur odor; this observer shared photographs of the cone and the summit crater with AVO. Comparisons with other recent photographs of Martin suggested no significant change in activity. Previous overflights of Martin routinely noted sulfur smell and gas measurement flights typically measure both SO2 and H2S (Doukas and McGee, 2007).\r\n\"On June 27, climbers ascended the volcano and reported a strong sulfur odor upon reaching the crater rim. Gas concentration was strong enough to cause coughing and a burning-throat sensation. They described roaring and bubbling noises coming from the crater lake and three fumaroles located on the triangular peak 'below the summit cone on the northeastern side of Mount Martin.' Additionally, 'snow on the entire final summit cone was tinged yellow from sulfur. . . .' These attributes previously have been noted at Martin during many AVO field visits to the volcano and are considered typical.\"","StartYear":2012,"StartMonth":4,"StartDay":11,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Martin","ParentVolcano":"Martin","VolcanoID":"ak189","ParentVolcanoID":"ak189"},{"ID":921,"Name":"Spurr 2012/6","Description":"From Herrick and others (2014): \"In January [2012], the number of located earthquakes beneath Mount Spurr increased over background. By January 30, the rate of small events was 1-3 events per hour, increasing to 2-4 events per hour on January 31. Seismicity remained slightly elevated into early February (up to 2-6 events per hour) but abated by February 12. AVO seismologists attributed the swarm to deformation within glaciers covering the edifice triggered by unseasonably warm weather. Several deep, low frequency events also occurred in February and March, but this was not considered a significant departure from background.\r\n\"On May 15, a pilot familiar with the volcano reported sulfur odors, likely hydrogen sulfide, during an overflight of the Mount Spurr area. He noted typical fumarolic activity on the summit cone, describing white plumes rising vertically in calm wind conditions. Some yellow-tinged (sulfur) snow was visible, but otherwise, the pilot reported no significant changes in the summit region. Snow continued to slowly infill the southern portion of the 2004 summit melt cauldron (Coombs and others, 2006) compared to previous views. An airborne gas measurement flight to Mount Spurr on June 22 took advantage of clear conditions to photograph the summit area. White vapor plumes rose from the long-lived fumarolic vents within the summit crater. Sulfur-dioxide (SO2) flux was low, but flying conditions were difficult and the aircraft may have been unable to travel completely below the plume (C. Werner, USGS, written commun., 2012).\r\n\"On June 25, a glacial outburst flood was recorded on seismograph station CKN located downstream of the Kidazgeni Glacier that flows from the Mount Spurr summit icefield and around the eastern flank of Crater Peak. Based on the duration of seismicity, the event lasted at least 45 minutes. Later observations indicated that water had escaped from beneath the Kidazgeni Glacier, flowing downstream and into the Chakachatna River that drains into Cook Inlet. By June 27, seismicity related to the outburst flood at ended. The seismic record of this event was similar to that observed during another Kidazgeni outburst flood in 1993 (Nye and others, 1995).\r\n\"On October 17, a pilot contacted AVO to report visible vapor emissions from the summit area of Mount Spurr. After AVO staff reviewed avialable satellite images, the local web camera, and seismic data, it was determined that no significant change had occurred. Slightly elevated surface temperatures were detected at Mount Spurr in satellite images on October 18 and 23, however, they were not considered significant departures from background.\"","StartYear":2012,"StartMonth":6,"StartDay":25,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Spurr","ParentVolcano":"Spurr","VolcanoID":"ak260","ParentVolcanoID":"ak260"},{"ID":951,"Name":"Little Sitkin 2012/8","Description":"From Herrick and others (2014): \"Seismic activity at Little Sitkin began to increase on August 22. Although volcano-tectonic earthquakes accounted for most of the seismicity, some unusual signals also were observed, most notably monochromatic earthquakes. A series of 5 monochromatic earthquakes that had unusually low resonant frequencies (0.6 Hz) that occurred during August 24-28. These earthquakes occurred at depths depths between 10 and 20 km (6-12 mi) and were recorded on seismic stations as far away as 80 km (50 mi) on Amchitka and Semisopochnoi Islands. These signals at Little Sitkin appear similar to that seen at Izu-Oshima Volcano in Japan (Ukawa and Ohtake, 1987). Two brief episodes of tremor also were recorded during this time.\r\n\"On August 30, earthquake activity escalated dramatically, prompting AVO to upgrade the Aviation Color Code and Volcano Alert Level to YELLOW/ADVISORY. AVO instituted a heightened seismic watch schedule to examine seismic data every 2 hours. An RSAM alarm was established for Little Sitkin to alert seismologists in the event of a sudden escalation in seismicity. Frequent earthquakes continued through August 31, then decreased during the first few days of September. Of the 110 earthquakes located during the first week of September, epicenters averaged 3.5 km (2.2 mi) from the summit. After a short flurry of earthquakes on September 13, seismicity decreased, but remained well above background. On September 24, AVO reduced the frequency of seismic data checks to once every 6 hours.\r\n\"Over the next 3 months, seismicity consisted of low-frequency tremor bursts with occasional brief swarms of VT events. Three notable flurries of seismicity occurred on October 13, 15, and 29. Another pulse of VT activity began on November 15 and continued through November 26. Six?hour seismic checks for Little Sitkin were discontinued on October 8.\r\n\"On January 9, 2013, after more than a month of relative quiet and continued decrease in overall seismicity, AVO downgraded the Aviation Color Code and Volcano Alert Level to GREEN/NORMAL. (Note that prior to the onset of seismicity and upgrade to YELLOW/ADVISORY in August, the volcano had been designated UNASSIGNED. Technically, it should have returned to UNASSIGNED, but this did not happen until March 29, 2013).\r\n\"Satellite images of the largest hot spring area west of the modern Little Sitkin cone showed that no significant change had occurred in the area since the last observations in late-October and early-September 2012. AVO received no reports from mariners or air crews of any changes at the surface; however, this part of the Aleutian Arc receives few visitors throughout the year and minor changes in activity could well go unnoticed.\r\n\"Subsequent analysis of InSAR results from images that span the time period of increased seismicity indicates 1-2 cm (0.4-0.8 in.) of inflation beneath the modern Little Sitkin cone. This result, along with the evolution of the seismic sequence in 2012, strongly suggests a magmatic intrusion as the source of observed seismicity and geodetic change (Haney and others, 2014).\"","StartYear":2012,"StartMonth":8,"StartDay":22,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2012,"EndMonth":11,"EndDay":26,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Little Sitkin","ParentVolcano":"Little Sitkin","VolcanoID":"ak182","ParentVolcanoID":"ak182"},{"ID":4311,"Name":"Geyser Bight 2013","Description":"From Dixon and others, 2017: \"The Geyser Bight Valley is a geothermal area (Nye and others, 1992; Motyka and others, 1993) southeast of Mount Recheshnoi (fig. 21 [original text]). In 2007, the seismograph network on neighboring Okmok Caldera recorded a short earthquake swarm in October. Following a 5-year period of quiescence, seismic activity increased in the Geyser Bight area in 2013 and continued through July 2015. The vast majority of the earthquakes located in 2015 were at shallow depths, less than 7 km (4 mi) with earthquake magnitudes between ML= 0.5 and ML=1.5. Seven earthquakes were larger than ML=2.0; the largest earthquake was a ML=3.0 event on June 30. Because this sequence of earthquakes occurred well away from a historically active volcano, no change in the alert status was made at any neighboring volcanoes.\"","StartYear":2013,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2015,"EndMonth":7,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Recheshnoi","ParentVolcano":"Recheshnoi","VolcanoID":"ak229","ParentVolcanoID":"ak229"},{"ID":1071,"Name":"Akutan 2013/1","Description":"From Dixon and others (2015): \"Following the M=7.5 Queen Charlotte earthquake in southeast Alaska on January 5, 2013, the seismograph network on Akutan Volcano recorded episodes of phase modulated tectonic tremor. Other possible earthquake-triggered seismicity was noted at nearby Westdahl and within the Katmai volcanic cluster. AVO internal log entries periodically noted tremor at Akutan, with tectonic tremor as the most probable origin. Short sequences of low-frequency earthquakes were located on February 8, May 29, and September 13, with a small swarm of volcanic-tectonic events reported on July 12. The Aviation Color Code and Volcano Alert Level remained at GREEN/NORMAL throughout the year.\"","StartYear":2013,"StartMonth":1,"StartDay":5,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":1061,"Name":"Shishaldin 2013/2","Description":"From Dixon and others (2015): \"In the first 2 months of 2013, persistent long-period earthquakes, occurring in pairs, continued at Shishaldin Volcano from activity that started in 2012 (fig. 34 in original text). This persistent seismicity, commonly seen on seismograph stations SSLN and SSBA, is similar to events seen by Caplan-Auerbach in 2003 (Caplan-Auerbach and Petersen, 2005) and is thought to be caused by fluid flow in a conduit. The initial signs of a failing network were seen in March, and by the end of the year, the lone broadband seismograph station in the Shishaldin network was the only reliable station for monitoring, preventing a full description of the seismicity in 2013. The long-period events that have been commonplace on the Shishaldin seismograph network since the 1999 eruption continued throughout the year. In 2013, one report of steaming from the Shishaldin summit was documented on clear Web camera views. Such clear views of Shishaldin are unusual, and the noted activity is typical of persistent degassing from Shishaldin that is not often seen because of poor visibility. The Aviation Color Code and Volcano Alert Level remained at GREEN/NORMAL throughout the year.\"","StartYear":2013,"StartMonth":2,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":1021,"Name":"Iliamna 2013/2","Description":"   From Dixon and others (2015): \"Activity at Iliamna Volcano in 2013 was highlighted by the observation of three significant rock/snow/ice avalanches, which often are seen on Iliamna. Monitoring highlights included a flight to measure gas emissions in April and substantial upgrades to AVO's geophysical monitoring network in August and September. Iliamna began 2013 at Aviation Color Code and Volcano Alert Level YELLOW/ADVISORY, based on seismicity interpreted to be caused by a magmatic intrusion (Neal and others, 2012). On January 9, 2013, citing decreasing seismicity, AVO downgraded the Aviation Color Code and Volcano Alert Level to GREEN/NORMAL, and Iliamna remained at this level throughout the rest of 2013.\r\n   \"On February 2, 2013, seismic signals indicated that a substantial avalanche had occurred on the eastern flank of Iliamna on the Red Glacier (fig. 3 in original text) at 13:58 UTC (4:58 a.m. AKST). This slide was preceded by 3 days of elevated seismicity with more than 40 earthquakes, several as large as ML=3. An hour before the avalanche, small, repeating earthquakes occurred, gradually increasing in rate to merge into a continuous signal. After about 5 minutes of sustained broad-frequency signal, the sequence abruptly ended, signaling the end of the avalanche. This avalanche also produced a signal seen on the infrasound array at Dillingham, Alaska, approximately 320 km (200 mi) southwest of Iliamna. Poor weather obscured views of the volcano, and prevented immediate visual confirmation of the avalanche. AVO mentioned the avalanche in the February 8, 2013 weekly update, noting that avalanches are common at Iliamna, and are not indicative of volcanic unrest. Later in February, AVO received visual confirmation of the avalanches when a local resident sent photographs from early February, showing the avalanche deposits on the Red Glacier (fig. 4 in original text).\r\n   \"On April 18, AVO scientists conducted a gas-measurement flight to Iliamna. During this flight, they detected emissions slightly greater than Iliamna's long-term background values (C. Werner, U.S. Geological Survey, written commun., 2013). Iliamna's typical fumaroles were visible and documented by AVO observers on the gas-measurement flight.\r\n   \"On July 24, a citizen observer used the 'Is Ash Falling?' notification system on AVO's Web site to report 'increased' steaming without ash on Iliamna's eastern flank during the evenings of the week of July 15. AVO noted no anomalous seismicity or evidence of increased steaming in satellite data. When Iliamna is backlit in the evening hours, as viewed from the Kenai Peninsula, its normal fumarolic plume often appears more prominent.\r\n   \"During August and September, AVO improved and upgraded geophysical equipment at Iliamna. Two new broadband seismometers were installed at pre-existing station sites ILW and IVE with a Web camera at site IVE.\r\n   \"Satellite data from August 25 showed two modest avalanches down the northern-northeastern flank of Iliamna. On September 20, AVO received photographs of a new, significant, eastern flank avalanche at Iliamna (fig. 5 in original text). AVO had incomplete seismic data through September and AVO was not able to find evidence of the event in the existing seismic data. As determined in satellite imagery, the avalanche had a headwall scarp measuring 300 m (980 ft) wide by 40 m (130 ft) tall; source-to-terminus, the feature was about 1,200 m (3,940 ft) long.\r\n   \"A photograph taken by a local resident on November 5 clearly depicts a flow feature on the eastern flank of Iliamna (fig. 6 in original text). A review of seismic records revealed a landslide at 16:32 UTC (7:32 AKST) on November 5. Careful analysis of seismic data on November 5 and 6 suggests two additional smaller avalanches after the larger one, although we do not have further photographic confirmation.\"","StartYear":2013,"StartMonth":2,"StartDay":2,"StartTime":"04:48:00","StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":1091,"Name":"Okmok 2013/3","Description":"From Dixon and others (2015): \"No eruptive activity was reported at Okmok Volcano, but seismic and geodetic observations of note were made in 2013. Sporadic tremor episodes and three swarms of earthquakes caught the attention of duty personnel in 2013. Geodetic instruments within the Okmok caldera detected a mid-year pulse of inflation. The Aviation Color Code and Volcano Alert Level remained at GREEN/NORMAL throughout the year.\r\n   \"On March 7, a 36-hour long swarm of over 1,000 low-frequency earthquakes was recorded on seismograph station OKTU, a station on Mount Tulik just outside the caldera (fig. 37 in original text). These earthquakes were too small to be recorded on adjacent stations and could not be located. The earthquakes formed two groups of earthquakes with similar waveforms (or earthquake families) that began at the same time, with the first earthquake family continuing for the duration of the swarm and the second family lasting for about the first 6 hours (fig. 38 in original text). Family 2 (short-duration family) contained larger events than family 1. After the family 2 (short-duration family) events ceased, the events in family 1 became larger and more infrequent than events earlier in the same earthquake family. Towards the end of the swarm, the event interval became more erratic, and the swarm ended abruptly.\r\n   \"Beginning in May 2013, the geodetic network at Okmok detected a pulse of rapid inflation, one of the steepest rises at Okmok since the 2008 eruption (fig. 39 in original text). The spatial pattern of the deformation is similar to past inflation events at Okmok, and points to an inflation source beneath the center of the caldera. In a study of ambient noise correlations between the Okmok stations OKNC and OKCE, evidence was found of 0.2-percent decrease in seismic velocity during late August and September within the caldera, indicating a change in composition of the crust sampled by the ray paths (Matt Haney, USGS/AVO, written commun., 2013). The geodetic and seismic evidence suggests an infusion of fluid or gas and, although it is certain that this was a change, it is not clear whether this change was magmatic or hydrologic.\r\n   \"A swarm of earthquakes began at 01:55 UTC on September 28 (17:55 AKDT on September 27) southwest of Okmok and northeast of Mount Recheshnoi in an active geothermal area. A second swarm occurred at Geyser Bight on October 9, forming a continuous zone of seismicity that extends from Recheshnoi towards Okmok (fig. 40 in original text). Neither swarm has led to eruptive activity and has continued to occur into 2014.\"\r\nFrom Cameron and others, 2017: \"Okmok volcano continued to inflate during 2014-a \r\ngeneral trend that started no more than 3 weeks after the volcano’s 2008 eruption (Freymueller and Kaufman, 2010). More specifically, analyses of GPS and InSAR data from 2008 to present (2016) show evidence for two major pulses of post-eruptive inflation (Qu and others, 2015). Inflation of the volcano began at a rapid rate immediately after eruption and slowed with time, largely ceasing by mid-2013. A new pulse of rapid inflation began at that time, its rate slowly decreasing over time. Inflation continued through 2014, although at a much slower rate.\"","StartYear":2013,"StartMonth":3,"StartDay":7,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2014,"EndMonth":12,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Okmok","ParentVolcano":"Okmok","VolcanoID":"ak206","ParentVolcanoID":"ak206"},{"ID":1101,"Name":"Korovin 2013/3","Description":"From Dixon and others (2015): \"Starting on March 29, Korovin Volcano experienced a 2-week-long swarm of small earthquakes located 2-4 km (1.2-2.4 mi) northwest of the summit of Korovin. Earthquake activity peaked on April 10, with a rate of 10 earthquakes per hour, and the swarm ended by April 12 (fig. 45 in original text). Throughout 2013, AVO noted isolated tremor at Korovin. In comparison, this tremor released about one-third of the energy level of tremor associated with a 2006 period of unrest at Korovin. The Aviation Color Code and Volcano Alert Level remained UNASSIGNED/UNASSIGNED throughout the year.\"","StartYear":2013,"StartMonth":3,"StartDay":29,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2013,"EndMonth":4,"EndDay":12,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Korovin","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak171","ParentVolcanoID":"ak17"},{"ID":1031,"Name":"Fourpeaked 2013/4","Description":"From Dixon and others(2015): \"A minor increase in seismicity at Fourpeaked Volcano in April and May prompted additional analysis of monitoring data by AVO. AVO also received a report in May of steaming near Mount Douglas and Fourpeaked. During 2013, the Aviation Color Code and Volcano Alert Level for Fourpeaked remained at GREEN/NORMAL.\r\n   \"A ML=4.5 earthquake occurred just west of Fourpeaked at 06:34 UTC (22:34 AKDT) on May 12. The Alaska Earthquake Information Center (AEIC) located this earthquake 15 km (9 mi) west of Fourpeaked and 25 km (16 mi) west-southwest of Mount Douglas at 15 km (9 mi) depth. This earthquake was immediately preceded by two foreshocks. A dozen small earthquakes occurred in this region in the 3 days before the ML=4.5. Another ML=4.5 earthquake occurred near Fourpeaked at 02:33 UTC (18:33 AKDT) on May 14, about 40 hours after the first earthquake. Comparison of the initial waveforms of the earthquake on seismograph station KABU suggests that both earthquakes had the same location and similar focal mechanisms. AVO analysts located 28 earthquakes in the 2 weeks following the second mainshock. It is unknown if this series of earthquakes are volcanic, but no observations of increased volcanic activity were received.\r\n   \"On May 19, a crew of Alaska Department of Fish and Game biologists reported steaming near Mount Douglas and Fourpeaked. AVO followed up on this report, noting that the lake at Mount Douglas froze over in previous years but did not freeze in 2013, which is likely the cause of the isolated report.\"","StartYear":2013,"StartMonth":4,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2013,"EndMonth":5,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Fourpeaked","ParentVolcano":"Fourpeaked","VolcanoID":"ak103","ParentVolcanoID":"ak103"},{"ID":713,"Name":"Cleveland 2013/5","Description":"From Dixon and others (2015): \"AVO continued to observe persistently elevated surface temperatures in satellite data (weather permitting) throughout the spring [of 2013]. At 12:59 UTC (04:49 AKDT) on May 4, the Okmok infrasound and seismic networks recorded an explosion from Cleveland. In response, AVO raised the Aviation Color Code and Volcano Alert Level to ORANGE/WATCH. A small ash cloud was first visible in satellite imagery at 13:48 UTC (06:48 AKDT). Over the next 3 hours, a small, detached cloud moved east and then southeast from the volcano and was last discernable about 200 km (125 mi) downwind. The explosion was followed by a period of infrasonic tremor interpreted as continuous low-level emissions (gas and [or] ash) from the vent. May 5 satellite images, including an unusual elevated temperature signal in AVHRR data, showed a small patch of ash at the Cleveland summit (fig. 41). Residents of Nikolski, 74 km (46 mi) away, reported a booming noise about 8:00 p.m. local time on the same day; however, no correlative explosion was detected with infrasound or other techniques.\r\n   \"On May 6, infrasound sensors and analysis of airwave signals detected three explosions from Cleveland (table 8 in original text). Satellite observations that day showed that the Cleveland summit crater filled nearly to the rim with tephra; the crater floor was marked by a 15 m (57 ft) diameter vent. New flowage deposits, including a lobe of lava (identified days later during reanalysis), extended down the upper northeastern, eastern, and southeastern flanks of the volcano. The lava flow lengthened over the next week, suggesting continued extrusion of lava from the summit vent. Details of the timing of lava extrusion with respect to explosions on May 6 remain unclear. Satellite images into June captured elevated temperatures in the summit area related to this activity (fig. 42 in original text).\r\n   \"Cleveland remained at Aviation Color Code and Volcano Alert Level ORANGE/WATCH until June 4, when AVO downgraded the status to YELLOW/ADVISORY. On July 26, analysis of a Landsat 8 image suggested new lava within the summit crater (fig. 43 in original text); it is possible extrusion of this lava occurred during a period of elevated temperatures and visible plume from the Cleveland summit during the prior week. AVO remained at YELLOW/ADVISORY and apparently this new lava never overtopped the crater rim, as it had in early May.\r\n   \"From early July through the end of 2013, AVO's infrasound and seismic networks detected a number of additional explosions and periods of infrasonic tremor at Cleveland (table 8 in original text). Most of these events did not have an accompanying ash signal in AVHRR satellite images, suggesting minor to no ash emissions during the events. It is entirely possible that very brief emissions of ash went unnoticed because of weather and gaps between satellite passes.\r\n   \"On December 28, a Cleveland explosion triggered the AVO infrasound alarms on both the Okmok and Akutan arrays at 21:29 UTC (12:29 AKST). Strongly elevated surface temperatures in the summit area appear in a satellite image 10 minutes prior to the explosion. Following a second explosion 2 days later, a small ash cloud was visible 73 km (45 mi) north of the volcano. Despite this activity, AVO remained at Aviation Color Code and Volcano Alert Level YELLOW/ADVISORY because these ash clouds were quite small, likely less than 20,000 ft ASL, and short-lived.\r\n   \"The 2013 activity at Cleveland is a continuation of the intermittent explosive and effusive activity that has occurred for much of the time since its last significant eruption in 2001 (Dean and others, 2004).\"\r\n   Cleveland began 2014 with three explosions generating minor ash plumes. Explosions were detected on December 28, December 30, and January 2. On January 2, citing increased explosions and minor ash plumes, AVO raised the Aviation Color Code and Alert Level to ORANGE/WATCH. Analysis of satellite, wind, and ash dispersion data indicates that the Dec 30 and Jan 2 plumes probably did not reach more than 15,000 ft above sea level. No new activity was observed after the January 2 explosion, and AVO lowered the Color Code/Alert Level to YELLOW/ADVISORY on January 10, 2014.\r\nOther than weakly elevated thermal anomalies in satellite imagery, no activity was observed at Cleveland until February 19, 2014 when a small steam plume was observed. On February 24, satellite data detected increased heat at Cleveland's summit. The following day, infrasound and lightning and alarms detected two small explosions at Cleveland Volcano at about 4:17 UTC February 25 (19:17 AKST February 24) and 10:35 UTC (1:35 AKST) February 25. Satellite data available several hours after these events occurred confirm that small ash clouds were generated by the explosions. The events were brief, and the estimated altitude of the drifting ash clouds was about 5 km (16,000 ft) asl. Satellite obsevations following the explosion show deposits of ash and large lava blocks on the upper flanks, extending 2.5 km (1.5 mi) from the summit. This suggests that these explosions were more energetic than those commonly observed over the past several years. However the ash emissions were brief and relatively low altitude, typical of recent Cleveland activity. The Color Code/Alert Level remained at YELLOW/ADVISORY.\r\nFrom Cameron and others, 2017: \"On March 6, residents of Nikolski village on the southwestern end of Umnak Island 73 km (45 mi) northeast of Cleveland reported dark ash rising from Cleveland at about 03:30-04:00 UTC on March 7 (6:30 or 7 p.m. AKST, March 6). In later discussions by telephone, residents further reported that, over a period of about 40 minutes, before the volcano became obscured by weather, alternating clouds of white steam and dark ash rose above the summit; the dark ash clouds rose about twice as high as white clouds but both dissipated quickly. Similar activity had been noted several months prior, so it is likely that other small episodes of ash emission have gone undocumented in the AVO database of eruptive activity from Cleveland during cloudy conditions \r\nwhen visual observations could not be made. The activity on March 6 was too ephemeral or small to be noted even in clear satellite views.\"","StartYear":2013,"StartMonth":5,"StartDay":4,"StartTime":"04:49:00","StartQualifier":null,"StartQualifierUnit":null,"EndYear":2014,"EndMonth":3,"EndDay":6,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":723,"Name":"Pavlof 2013/5","Description":"From Dixon and others (2015): \"Pavlof Volcano erupted in May 2013 and was characterized by Strombolian explosions and periods of continuous tremor. Eruption plumes deposited trace amounts of ash in nearby communities during the first 2 weeks of the eruption and again in early June. Activity and observations are summarized in table 7 [in original text]. Pavlof was upgraded from the Aviation Color Code and Volcano Alert Level of GREEN/NORMAL to ORANGE/WARNING on May 13, remaining at ORANGE/WARNING for 17 days during the 3-week-long eruption, with remainder of the time at YELLOW/ADVISORY. On August 8, the Aviation Color Code and Volcano Alert Level were downgraded to GREEN/NORMAL, where it remained for the rest of the year.\r\n   \"The 2013 eruption of Pavlof Volcano began on the morning of May 13, 2013, following a 6-year period of repose. Eruption onset was characterized by subtle, low-level seismicity beginning about 16:00 UTC (08:00 AKDT) and continuing for the first 24-48 hours of the eruption. A strong, persistent thermal signal from the Pavlof summit area was first observed in mid-infrared AVHRR satellite imagery at 15:17 UTC (07:17 AKDT) on May 13, and AVO upgraded the Aviation Color Code and Volcano Alert Level to ORANGE/WATCH, stating that an eruption was likely to progress. A pilot report at 03:00 UTC on May 13 (19:00 AKDT, May 14) confirmed the eruption, with numerous dark streaks on the upper northern flank of the volcano that appeared to be a lava flow and lahars initiated by melting of snow and ice in the summit area (fig. 28 in original text). Similar flows also were observed farther down the northern flank and that were initiated by the ejection of hot debris onto snow and ice. Residents of Sand Point, 85 km (53 mi) east of the volcano, reported seeing a distinctive glow at the summit of Pavlof during the evening of May 13, indicating likely lava fountaining. By the next day, satellite observations showed that a lava flow extending down the northern flank well beyond the summit vent. The flow was estimated to be about 600 m (2,000 ft) long and 30 m (100 ft) wide, and originated from a vent within a small crater just north of the summit.\r\n   \"AVO received numerous observations on May 14 confirming eruptive activity underway at Pavlof Volcano. Pilot reports and Web camera views of the volcano indicated that ash emissions as high as about 4 km (13,000 ft) ASL were occurring intermittently. Views of Pavlof, such as that in figure 29 [in original text], indicated several light-colored plumes rising off the lower northern flank, suggesting flowage of hot debris over ice and snow. Throughout the day on May 14, numerous strong bursts of tremor coincided with similar observations of large steam plumes rising off the northern flank of the volcano. Light-colored plumes from some of these events reached as high as 6 km (20,000 ft) ASL. Incandescence associated with strong lava fountaining at the summit also was observed throughout the evening of May 14. The lava fountaining was robust enough that relatively continuous infrasonic tremor was produced and recorded on infrasound arrays on Akutan Island (290 km [180 mi] southwest of Pavlof) and Okmok (460 km [285 mi] southwest of Pavlof) Volcanoes and at Dillingham (455 km [283 mi] northeast of Pavlof).\r\n   \"Noticeable fallout of fine ash occurred as far as 80 km (50 mi) downwind of the volcano on May 14, 15, and 18, and was reported to AVO. During May 15-20, sulfur dioxide (SO2) from Pavlof was detected in OMI satellite data; the estimated SO2 mass during May 15-16 was 1,000-2,000 metric tons and at least 4,000 metric tons on May 18-20 (Simon Carn, written commun., 2013). Sulfur dioxide also was detected on multiple days by the GOME-2 (Global Ozone Monitoring Experiment-2) and IASI (Infrared Atmospheric Sounding Interferometer) instruments.\r\n   \"From May 15 to 21, the eruption was characterized by nearly continuous tremor and explosions. A relatively continuous ash plume was apparent in AVHRR and MODIS satellite images and also was observed by pilots. Ash emissions during this period reached as high as 7 km (23,000 ft) ASL and extended about 400-500 km (250-310 mi) southeast of the volcano on May 18 (fig. 30 in original text). On May 19, trace amounts of ash fall occurred on the communities of Sand Point and Nelson Lagoon, 90 km (56 mi) southwest and northeast of Pavlof, respectively. AVO scientists examined an ash sample collected in Sand Point that consisted almost entirely of dark angular glass shards. A single electron microprobe analysis of the glass indicated that it is compositionally andesite (58 percent silicon dioxide, SiO2) and similar to ash deposits associated with previous historical eruptions (K. Wallace, USGS-AVO unpub. data; microprobe analyses by L. Hayden, USGS).\r\n   \"From May 22 to June 4, the volcano was relatively quiet, and the seismicity during this period was characterized by episodic, discrete bursts of tremor lasting from 30 seconds to approximately 1 minute. During May 22-23, the Pavlof seismic network detected distinct ground-coupled airwaves. Infrasonic arrays at Dillingham and Okmok Volcano also recorded these probable explosion signals as impulsive infrasonic waves.\r\n   \"From May 27 to June 4, seismic tremor and small discrete explosions were no longer detected in seismic and infrasound data. Satellite observations during this period showed no evidence of elevated surface temperatures, volcanic gas (SO2) or ash emissions. During periods of clear weather, no visual observations of ash emissions and Web camera views of the volcano were noted, indicating eruptive activity had paused. These observations prompted AVO to downgrade the Aviation Color Code and Volcano Alert Level to YELLOW/ADVISORY at 20:50 UTC (12:50 AKDT) on May 27.\r\n   \"On June 4, 2013, AVHRR, MODIS, and GOES satellite data detected ash emission from Pavlof; passing pilots reported ash plumes as high as 5.7 km (18,700 ft) ASL. Slightly elevated levels of seismic tremor also were observed by midday (local) on June 4, roughly coincident with the observations of ash emissions, prompting an upgrade to ORANGE/WATCH at 12:15 UTC (20:15 AKDT). From June 14 to 19, seismic activity was characterized by periods of intermittent volcanic tremor and slightly more robust and more frequent explosions compared to the character of the seismicity from May 13 to 24. During this period, ash plumes generally were smaller and did not extend more than about 50 km (30 mi) downwind of the volcano. The maximum plume height reported by pilots was approximately 6 km (29,000 ft) ASL on June 10. Residents of Cold Bay reported barely perceptible trace ash fall during June 6-7.\r\n   \"From June 20 to 24, the Pavlof seismic network recorded moderate levels of relatively continuous tremor and small explosions. Several low-level ash plumes (generally less than 3.5 km or 11,500 ft) ASL were generated, although cloud cover occasionally inhibited observations.\r\n   \"Beginning around 07:00 UTC on June 25 (23:00 AKDT on June 24), tremor amplitudes at the volcano increased significantly and were characterized by high levels of continuous tremor and frequent explosions associated with robust episodes of lava fountaining and ash emission. The level of seismicity on June 25 was the strongest detected during the entire eruption. Observers in Sand Point reported incandescence and ash plumes as high as 6 km (20,000 ft) ASL on the morning of June 25, and around midnight on June 25, ash fall was reported in King Cove 50 km (30 mi) southwest of the volcano. Analysis of satellite images and pilot reports confirmed ash plumes as high as 7-8 km (23,000-26,000 ft) ASL. Sulfur dioxide emissions from Pavlof were detected by the Joint Polar Satellite System Ozone Monitoring Profiler Suite from 01:00 to 23:10 UTC on June 25. Automated analysis of this data indicated a mass of SO2 of 6,000-7,000 metric tons near the volcano. \r\n   \"Between June 25 and 27, intermittent ash plumes rose to 6 km (20,000 ft) ASL. After June 27, the seismicity became less energetic, and occasional low-frequency events and low levels of increasing discontinuous tremor characterized the seismicity. Pilot reports on June 28 indicated no activity at the volcano, and over the next several days, seismic tremor and small discrete explosions were no longer detected in seismic and infrasound data. Satellite observations after July 1 showed no evidence of elevated surface temperatures, volcanic gas, or ash emissions. On July 2, AVO downgraded the Aviation Color Code and Volcano Alert Level to YELLOW/ADVISORY, where it remained until August 8 when the volcano returned to its normal background state and the Aviation Color Code and Volcano Alert Level were downgraded to GREEN/NORMAL.\r\n   \"The lahars and ash plumes generated during the eruption did not pose any serious hazards for the area. However, numerous local airline flights were cancelled or rerouted, and trace amounts of ash fall occurred at all local communities surrounding the volcano, including Cold Bay, Nelson Lagoon, Sand Point, and King Cove. Observations by AVO scientists during July 16-17 indicated that only the upper part of the Cathedral River drainage (fig. 31 in original text) had been inundated by lahars. However, a fountain-fed lava flow, about 5.8 km (3.6 mi) in length, covering an area of about 730,000 m2 (180 acres) on the northern flank of the volcano was observed (fig. 32 in original text). It was only possible to collect a few samples of the lava. These samples have not yet been analyzed (as of July 2015), but appeared similar to other andesitic lava flows produced by historical eruptions of Pavlof.\"","StartYear":2013,"StartMonth":5,"StartDay":13,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2013,"EndMonth":7,"EndDay":26,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":733,"Name":"Veniaminof 2013/6","Description":"From Dixon and others (2015): \"Mount Veniaminof Volcano is a frequently active volcano on the Alaska Peninsula. From 2002 through 2010, nearly continuous low-level eruptive activity waxed and waned, producing wispy plumes that were reported by pilots, recorded on satellite images, and observed in images from the Federal Aviation Administration (FAA) Web camera in Perryville, 35 km (22 mi) east of the volcano. Activity ceased during the first one-half of 2013. In early June 2013, a several-day period of abrupt and gradually increasing levels of seismic tremor heralded the onset of a largely effusive eruption from the intracaldera cinder cone (table 6 in original text). Over the next 5 months, ash emissions and Strombolian explosions accompanied by five lava flows poured down the flanks of the active cone and advanced onto the surrounding ice-filled caldera. This eruption constructed a new spatter cone within the summit crater of the main active cone (Waythomas, 2013).\r\n   \"On June 7, 2013, gradually increasing, low-frequency tremor was recorded on two seismograph stations (VNWF and VNHG) as satellite images recorded elevated surface temperatures at the summit of the intracaldera cinder cone (fig. 10 in original text). The following day, June 8, in response to the continuing increase in seismic tremor, AVO upgraded the Aviation Color Code and Volcano Alert Level from GREEN/NORMAL to YELLOW/ADVISORY. Over the next several days, seismic tremor steadily increased. On June 13, seismicity levels and elevated surface temperatures at the summit of the cinder cone, as observed in satellite images indicated an eruption was likely underway. AVO issued a Volcanic Activity Notice (VAN) upgrading the Aviation Color Code and Volcano Alert Level from YELLOW/ADVISORY to ORANGE/WATCH. On June 14, ash deposits on the ice/snow-covered caldera floor were visible in satellite images, and the presence of lava on the cone was observed.\r\n   \"Clear weather provided good views from the FAA Web camera, located in nearby Perryville, as the eruptive activity increased and produced minor ash clouds (fig. 11 in original text). Satellite views on June 18 confirmed the Strombolian eruption and effusion of a 100 m (330 ft) wide lava flow (Flow 1; flow numbers refer to those identified in figure 12 [in original text] down the southwestern flank of the main cinder cone). Interaction of the lava with the caldera snow and ice field at the base of the main cone generated water-rich, ashy plumes (fig. 13 in original text). Clear satellite views the following day showed active flow lobes advancing over the ice at the base of the cone (fig. 14 in original text).\r\n   \"For the next couple of weeks, the activity continued with the southern flank flows (Flows 1 and 2) advancing and widening, with minor accumulations of ash on the caldera floor (figs. 15 and 25 in original text); Flow 2 descended east and adjacent to Flow 1, and Flow 3 advanced between and over the margins of Flows 1 and 2. The Strombolian eruption was visible in infrared satellite imagery, from the FAA Web camera in Perryville, and from several local lodges and remote camps (figs. 16 and 17 in original text).\r\n   \"On July 16, AVO geologist Chris Waythomas visited the caldera by helicopter, making observations and taking the first close-up photographs documenting the lava flows and ice cauldron formation (figs. 18 and 19 in original text). These close-up images of the vent area showed a new cone of accumulated spatter nested within the summit crater of the main cone.\r\n   \"By late July, the activity appeared to be waning as seismicity decreased, and reached a low level by August 2. In clear satellite views over this period, elevated surface temperatures were consistent with the still cooling, but no longer advancing, lava flow. On August 11, seismic tremor increased abruptly, and very high surface temperatures were observed in satellite images, suggesting that eruptive activity had resumed and lava again was flowing from the summit vent. Nighttime satellite images on August 12 confirmed lava erupting from the cone, and a clear morning view from the Perryville Web camera showed a minor ash column and cloud over the summit cone.\r\n   \"On August 18, AVO geologist Game McGimsey accompanied Ben Edwards, Dickinson University, on a National Geographic Society-sponsored visit to the caldera to document the ongoing activity, particularly the interaction of lava flows and the surrounding ice field. The southern flank lava flows had coalesced and largely melted into the ice, enlarging the ice cauldrons documented in July by Chris Waythomas, USGS/AVO (fig. 20 in original text). Steam rose from the margins where the hottest parts of the flows were still in contact with ice and water.\r\n  \"Strombolian explosions of incandescent lava and minor ash emissions were observed at the central active vent on August 18 (fig. 21 in original text). Two new lava flows issued either from tubes emerging from accumulations of spatter near the vent rim on the northeastern flank of the new cone, or from vents through the base of that cone. The flows descended to the ice field below, coalescing and forming another ice cauldron (fig. 22 in original text); forming Flow 4 (Waythomas, 2013). Voluminous steam generated by interactions of lava and ice/water obscured views into the cauldron. Forward Looking Infrared Radiometer (FLIR) images delineated the lava flows and hot spatter on the cone (fig. 22 in original text). As measured by the FLIR, maximum temperatures reached 700 to 800 degrees C.\r\n   \"Elongated lobes of sediment extended from the southern side of the ice cauldron, forerunners to the fifth and final lava flow of the eruption (figs. 23 and 24 in original text). Eruptive activity continued unabated for the next 12 days, and on August 30, AVO issued a VAN to report the intense seismicity, lava fountaining, and ash emissions as high as 15,000-20,000 ft (4,570-6,100 m) ASL. This marked the strongest unrest and eruptive activity since the eruption began in June. Satellite images on September 6 indicated further development of the lava flows on the northeastern flank (Flow 4), expansion of the main ice cauldron at its base, and creation of a second ice cauldron. A new lobe of the lava flow (Flow 5) also appeared in the satellite images, advancing southward from the main cauldron of Flow 4. The flow was captured in aerial photographs the following day (fig. 24 in original text). This flow continued to advance for possibly another week, but, by September 19, no evidence of active lava flows was observed in satellite images. Seismicity had begun to decrease during the week and the eruption appeared to be waning.\r\n   \"In response to the decrease in seismicity, and no evidence of eruptive activity in satellite and Web camera images, AVO issued a VAN on September 20 to downgrade the Aviation Color Code and Volcano Alert Level from ORANGE/WATCH to YELLOW/ADVISORY. An October 1 aerial image shows all five lava flows, partially snow covered, and only minor steam emissions from the summit vent (fig. 13 in original text).\r\n   \"On October 6, an abrupt increase in seismic tremor and the observation of highly elevated surface temperature indicated a resumption of lava effusion, and AVO responded by upgrading the Aviation Color Code and Volcano Alert Level to ORANGE/WARNING. No ash emissions were observed, and within a few days, seismicity began decreasing in what would be a downward trend coincident with the final end of eruptive activity in 2013. The Aviation Color Code and Volcano Alert Level were downgraded on October 17 to YELLOW/ADVISORY. Throughout the remainder of 2013, occasional elevated surface temperatures were observed in satellite images consistent with the cooling lava flows, and steam emission from the summit vent was visible on clear days in Web camera images.\r\n   \"The 2013 eruption of Veniaminof produced about 5 x 105 m3 of erupted lava, comparable in size to the 1983 eruption (Waythomas, 2013). A real-time seismic amplitude (RSAM) time series (Endo and Murray, 1991) from seismic station VNWF (fig. 11 in original text) is shown in figure 25 for the 5-month-long eruption, including significant eruptive events and color code changes (Waythomas, 2013). Before- and after-eruption views of the intracaldera cinder cone and geomorphic changes produced by the 2013 eruption are shown in figures 26 and 27 [in original text].\"\r\nFrom Cameron and others, 2017: \"The volcano gradually returned to a state of rest, and by early July 2014, seismicity had returned to normal background levels. AVO downgraded the Aviation Color Code and Volcano Alert Level to GREEN/NORMAL on July 9, 2014. Minor steam emissions and cooling of the lava flows continued intermittently for the remainder of the year. Several episodes of low-frequency events and tremor bursts occurred over the last one-half of the year (for example, July 15, October 8, December 18) as reported by AVO seismologists; however, these events were not associated with eruptive activity and are interpreted as continued degassing of the magmatic system.\"","StartYear":2013,"StartMonth":6,"StartDay":13,"StartTime":"05:25:00","StartQualifier":1,"StartQualifierUnit":"Days","EndYear":2013,"EndMonth":10,"EndDay":11,"EndTime":null,"EndQualifier":10,"EndQualifierUnit":"Days","Volcano":"Veniaminof","ParentVolcano":"Veniaminof","VolcanoID":"ak301","ParentVolcanoID":"ak301"},{"ID":1041,"Name":"Peulik 2013/6","Description":"From Dixon and others (2015): \"On June 18, AVO received a pilot report of 'smoke or steaming emerging from Mount Peulik,' but no anomalous activity was noted at the time of the report. On August 12, AVO received a second observation of unusual activity from a long-time guide in the area, reporting 'sulfur smell and lack of fish.' No similar reports were received and AVO did not investigate further.\"","StartYear":2013,"StartMonth":6,"StartDay":18,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2013,"EndMonth":7,"EndDay":12,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Peulik","ParentVolcano":"Ugashik-Peulik","VolcanoID":"ak212","ParentVolcanoID":"ak295"},{"ID":1111,"Name":"Great Sitkin 2013/7","Description":"From Dixon and others (2015): \"Two earthquake swarms were detected on seismic instrumentation at Great Sitkin Volcano during 2013, one in July and one in August. Both swarms consisted of about three dozen volcanic-tectonic earthquakes (fig. 46 in original text). Satellite data acquired September 3 showed a possible thermal feature, AVO determined that this was a signal from a known hot springs at the summit of Great Sitkin (fumarolic temperatures measured at 98 degrees C in 2005, Christina Neal, USGS/AVO, oral commun., 2013). The Aviation Color Code and Volcano Alert Level remained at GREEN/NORMAL throughout the year.\"","StartYear":2013,"StartMonth":7,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2013,"EndMonth":8,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":1121,"Name":"Gareloi 2013/7","Description":"From Dixon and others (2015): \"In July and August [2013], AVO duty personnel responded to observations from a USFWS crew conducting ornithology work on Gareloi Island. The initial reports were of 'tremors of a magnitude that were noticeable to crews working outside, moving around.' A check of the seismicity showed no unusual activity. The background activity at Gareloi, since seismic station installation in 2003, has been constant low-level seismicity consisting of low-frequency earthquakes at a rate of one per minute. In light of the 2008 evacuation of a USFWS crew at Kasatochi and the subsequent eruption of Kasatochi (Waythomas and others, 2010), AVO closely monitored seismicity at Gareloi during the late summer. Despite close scrutiny, no changes were noted in the seismicity, nor were there further observations of felt events. Although the cause of the felt earthquakes was not determined, the felt reports were forwarded to AVO offices a week after a July 7 ML=5.5 earthquake and aftershock sequence south of Gareloi. The felt reports did not include event timing, and the most plausible explanation is that the USFW crew felt regional earthquakes and not volcano-related seismicity.\r\n   \"The USFW crew also noted 'steam coming from the extensive fumarole area on the west peak' on July 30. Although this was a single observation, the field crew additionally commented that the weather on July 30 was unusually clear and allowed for the observation of steaming (fig. 47 in original text). Steaming at fumaroles on Gareloi is routinely seen, with observations of steaming in 2003 and 2005 (Michelle Coombs, USGS/AVO, written commun., 2005).\"","StartYear":2013,"StartMonth":7,"StartDay":30,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2013,"EndMonth":7,"EndDay":30,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Gareloi","ParentVolcano":"Gareloi","VolcanoID":"ak106","ParentVolcanoID":"ak106"},{"ID":1081,"Name":"Makushin 2013/8","Description":"From Dixon and others (2015): \"No eruptive activity occurred at Makushin Volcano in 2013, but increases in seismicity and reports of possible ash plumes prompted increased AVO attention. The Makushin seismograph network periodically recorded tremor episode during 2013, likely unrelated to volcanism. Short swarms of earthquakes are common near Makushin. Four such swarms were noted in the last one-half of the year on August 28, September 24, October 29, and December 25 (fig. 35 in original text). A single observation of a small steam plume was noted in a clear Web camera image of Makushin on March 24 (fig. 36 in original text). The Aviation Color Code and Volcano Alert Level remained GREEN/NORMAL throughout the year.\"","StartYear":2013,"StartMonth":8,"StartDay":28,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":4161,"Name":"Iliamna 2014/1","Description":"From Cameron and others, 2017: \"Iliamna Volcano during 2014 experienced several significant rock/snow/ice avalanches on its eastern flank, and numerous smaller avalanches. Seismic data indicated a likely avalanche at 12:11 UTC (3:11 a.m. AKST) on January 28. This event was identified primarily by its characteristic seismicity - precursory seismicity of small, discrete events transitioning into a continuous signal consistent with a slide (Scott Stihler, UAFGI/AVO, written commun., 2014). In mid-May, satellite imagery of Iliamna showed recent avalanche deposits extending about 1.5 km (0.93 mi) eastward from a near-summit source area (Christina Neal, USGS/AVO, written commun., 2014) that may have been the source of the seismic signal 4 months earlier.\r\n\"AVO conducted its annual overflight of Iliamna to measure gas concentrations on April 10, recording normal background levels of about 32 tons/d of SO2. Because of an instrument malfunction, CO2 was not measured on this flight (Cynthia Werner, USGS/AVO, written commun., 2015). Iliamna remained at Aviation Color Code and Volcano Alert Level GREEN/NORMAL throughout 2014. \r\n\"On July 20, AVO received a phone call from a citizen on the Kenai Peninsula reporting a new avalanche at Iliamna, identified by the presence of new dark streaks within the snowfield. A review of the seismic data showed that the avalanche likely occurred at about 16:00 UTC (8:00 a.m. AKDT) on July 20. The deposit extended about 2.8 km (1.7 mi) east from the summit (Rick Wessels, USGS/AVO, written commun., 2014). \r\n\"Satellite imagery from August 19 documented new fresh avalanches at Iliamna, slightly larger than those in July. In early October, AVO observed evidence for a small, recent landslide or avalanche on the upper headwall of the Red Glacier on the eastern side of Iliamna. A retrospective analysis of the seismic data showed that the avalanche likely occurred in the early morning of October 3 (Jacqueline Caplan-Auerbach, Western Washington University, written commun., 2014). This new avalanche extended about 2 km (1.2 mi) from its source area.\"","StartYear":2014,"StartMonth":1,"StartDay":28,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2014,"EndMonth":10,"EndDay":3,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":771,"Name":"Shishaldin 2014/1","Description":"From Cameron and others, 2017: \"In early 2014, Shishaldin Volcano began a low-level eruption that produced intermittent lava within the crater, low-level steam plumes, and occasional dustings of ash and ballistics on its upper flanks. This activity persisted from January 30 through the remainder of 2014. During the eruption, AVO monitored Shishaldin using the seismic array on Unimak Island, infrasound arrays at Akutan (135 km [84 mi] to the southwest) and Dillingham (582 km [362 mi] to the northeast), satellite imagery, a Web camera on adjacent Isanotski volcano looking northwest to Shishaldin, mariner observations, and pilot reports.\r\n\"Web and satellite imagery of Shishaldin Volcano showed persistent, low-level steam plumes beginning on January 17, although such activity is not unusual at Shishaldin. On January 30, satellite data showed increased surface temperatures in the summit crater, and AVO upgraded theAviation Color Code and Volcanic Alert Level to YELLOW/ADVISORY. Activity increased in early February, manifested by intermittent seismic tremor and airwave explosion signals recorded on distant infrasound instruments. On February 7, satellite data showed an ice-rich cloud at altitudes as high as 7,600 m (25,000 ft) ASL coming from Shishaldin, and AVO increased the daily watch schedule. Although this activity may have indicated a low-level eruption present in the summit crater, the eruption began no later than March 25, when satellite data indicated temperatures in the summit crater consistent with lava extrusion, and seismic and infrasound data recorded small explosions. On March 28, citing the inferred presence of lava in the summit crater, AVO upgraded the Aviation Color Code and Volcano Alert Level to ORANGE/WATCH. On March 30, 2014, a passing mariner photographed a darkened area at the crater rim, likely from a minor ash emission. \r\n\"Throughout April, seismic and infrasound stations continued to record intermittent explosion signals, and steaming often was visible in clear Web camera views. On April 26, AVO received a PIREP of a steam plume at Shishaldin at an altitude as high as 3,800 m (12,500 ft) ASL. Probable ash darkened the upper flanks of the summit crater in Web camera images taken on May 5. On May 13, AVO again observed elevated surface temperatures at the crater consistent with lava extrusion in the crater. One month later on June 14, a NASA Earth Observing-1 Advanced Land Imager (EO-1 ALI) image showed a dusting of ash on the snow around the summit crater. A mariner report on June 28 also described a slight dusting of ash on the snow, and satellite data from July 1, 17, and 27 showed fresh deposits of ash on the flanks of the edifice, suggesting persistent, low-level eruptive activity within the summit crater, consistent with heightened seismicity and elevated surface temperatures. \r\n\"AVO personnel conducting fieldwork photographed incandescence within the summit crater on August 10, 2014. Activity at Shishaldin remained remarkably consistent throughout August and September-elevated surface temperatures observed in satellite imagery, evidence of explosions from infrasound and seismic data, intermittent tremor, and occasional steam plumes viewed by pilots or in the Web camera. \r\n\"On October 1, satellite data again indicated temperatures within the summit crater consistent with extrusion of new lava. However, these elevated temperatures decreased by mid-October. Temperatures increased again on October 25, consistent with the reappearance of lava within the summit crater. This was accompanied by an increase in seismic tremor and explosions detected by infrasound. In response, AVO issued a Volcanic Activity Notice (VAN) on October 28 but the Aviation Color Code and Volcanic Alert Level remained at ORANGE/WATCH. After an apparent lull in eruptive activity between November 3 and November 20, the number and size of earthquake events at Shishaldin increased sharply, and AVO increased the watch schedule. At 10:00 UTC (1 a.m. \r\nAKST) on November 24, seismic activity again increased sharply, prompting AVO to issue another VAN at 10:49 UTC (1:49a.m. AKST) warning of a greater risk of ash emission outside the crater. For the next 2 days, surface temperatures increased and there was an increase in the number of seismic events and explosions detected by infrasound. A robust steam plume was observed in satellite imagery, but no significant ash deposition occurred outside the crater. This slightly elevated activity lasted 2 days, after which the usual low-level eruptive activity continued at Shishaldin into 2015.\"\r\n    In late January 2015, strongly elevated temperatures were observed in satellite images, consistent with active lava within the crater. A wispy, low-leve ash emission was observed in webcam images on February 2, 2015.\r\nThroughout February and March, 2015, clear satellite views often show elevated surface temperatures at the crater, seismicity remained above background, and low-level steam emissions were frequently seen in webcam images. It is likely that low-level eruptive activity continued within the summit crater. On April 16, 2015, several pilot reports of an ash plume at Shishaldin resulted in the issuance of an Ash Advisory SIGMET. No ash was visible in satellite and web camera images. Throughout April, and until at least the time of this writing (May 15, 2015), Shishaldin continued to show evidence of low-level eruptive activity, including elevated seismicity, elevated surface temperatures within the summit crater, and a visible steam plume. On May 8, observers from a  cruise ship in the area reported a steam/ash plume from Shishaldin, heading east. On the morning of May 15, a robust steam plume was detected in web camera views, possibly containing small amounts of ash.\r\nLow-level eruption continued at Shishaldin throughout May, 2015. On June 18, 2015, pilot reports and satellite imagery indicated a weak ash plume rising a few hundred feet from the summit crater; weak ash emissions continued on June 19, 2015. Elevated seismicity, with intermittently observed elevated surface temperatures continued at Shishaldin throughout June, July, August, September, and October. \r\nOn November 20, 2015,  AVO lowered the Aviation Color Code and Volcano Alert Level to YELLOW/ADVISORY, because no elevated surface temperatures had been observed since October 19, 2015. Slightly elevated seismicity continued at Shishaldin, and robust steam plumes were often observed. \r\nOn March 10, 2016, AVO lowered the Aviation Color Code and Volcano Alert Level to GREEN/NORMAL, stating \"There has been an steady decrease in detected thermal activity at Shishaldin over the past several months. No anomalous activity has been observed in several clear satellite images of Shishaldin since moderately elevated surface temperatures were detected on January 13, 2016. Airwaves associated with low-level explosive degassing have not been detected in infrasound data since Feb. 7. Low-amplitude seismic tremor consistent with an open, degassing system system continues to be seen in seismic data and is considered to be within the bounds of background activity for Shishaldin.\"","StartYear":2014,"StartMonth":1,"StartDay":30,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2016,"EndMonth":1,"EndDay":16,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":4231,"Name":"Tanaga 2014/2","Description":"From Cameron and others, 2017: \"In February and March 2014, an earthquake swarm occurred about 13 km (8 mi) southwest of Tanaga Volcano. This was the most energetic volcano-tectonic swarm at Tanaga since 2005 (McGimsey and others, 2007). The elevated seismicity continued into the summer, although at a reduced rate, and ended in late 2014. The swarm comprised 80 percent of all earthquakes located on or near Tanaga during the year. The earthquakes were all less than M2.0 and occurred at crustal depths of 5-10 km (3-6 mi). No specific cause was determined for the short-lived swarm. Despite the swarm, the Aviation Color Code and Volcano Alert Level remained at GREEN/NORMAL for all of 2014.\"","StartYear":2014,"StartMonth":2,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2014,"EndMonth":3,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Tanaga","ParentVolcano":"Tanaga","VolcanoID":"ak280","ParentVolcanoID":"ak280"},{"ID":4221,"Name":"Kanaga unrest 2014/3","Description":"From Cameron and others, 2017: \"A short lived swarm 5 km (3.1 mi) east-northeast of Kanaga Volcano began on March 26, 2014, with 24 located earthquakes. The number and size of earthquake doubled the next day, and included earthquakes with magnitudes up to 1.1. On March 27, the swarm started to decrease in numbers and intensity, and by March 29 had ceased altogether. The total swarm encompassed 72 earthquakes large enough to locate. Subsequent satellite observations showed no changes at the summit following this short-lived earthquake swarm. The only other notable observation of Kanaga seismic data was the presence of 2-3 Hz monochromatic signals in late August through early September, which could be a sign of magma moving under the volcano. The Aviation Color Code and Volcano Alert Level remained at GREEN/NORMAL for all of 2014.\"","StartYear":2014,"StartMonth":3,"StartDay":26,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2014,"EndMonth":3,"EndDay":27,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kanaga","ParentVolcano":"Kanaga","VolcanoID":"ak144","ParentVolcanoID":"ak144"},{"ID":4171,"Name":"Novarupta 2014/5","Description":"From Cameron and others, 2017: \"Resuspension and transport of fine-grained volcanic ash from the Katmai National Park and Preserve region of Alaska frequently have been observed and documented for decades (Hadley and others, 2004; McGimsey and others, 2005), and five episodes of resuspended ash were documented in 2014. The 1912 eruption of Novarupta deposited large quantities of ash in valleys of the Katmai area, and the landscape remains desolate and largely vegetation-free, even more than a century later. During times of no snow and strong northwesterly winds, the ash can be resuspended and transported southeast across Shelikof Strait, Kodiak Island, and the Gulf of Alaska. These events commonly are identified by the presence of ash blowing from the Katmai area, often detected in satellite imagery, coupled with existing high winds and a lack of other volcanic signals (no thermal anomalies, no increased seismicity).\r\n\"On May 19, flights to Karluk on Kodiak Island were delayed because of weather conditions and a visible plume of resuspended ash originating from the Katmai area. The ash was weakly visible in satellite imagery, and strong northwesterly winds were blowing from the Katmai area towards the southeast. The National Weather Service Alaska Aviation Weather Unit (NWS AAWU) issued a Special Weather Statement. The NWS AAWU also issued SIGnificant METeorological information statements (SIGMETs) for resuspended Katmai ash due to strong winds on September 29 and October 5, when ash again was visible in satellite imagery blowing toward Kodiak Island. During the October 5 event, a citizen of Kodiak reported ash to AVO using via AVO’s \"Is Ash Falling\" system. Ash reached an altitude as high as 1,200-1,800 m (4,000-6,000 ft) ASL during the October 5 event.\r\nOn October 14, strong winds in the Katmai area once again picked up loose 1912 volcanic ash and carried it east over Shelikof Strait and Kodiak Island. The National Weather Service estimated the top of the cloud at an altitude of 1,200 m (4,000 ft) ASL. The NWS issued a Special Weather Statement, and AVO received a report of hazy conditions and trace ashfall (less than 1/32 in. deep) at Karluk on the southwestern side of Kodiak Island through AVO’s \"Is Ash Falling\" online ash reporting system. Federal Aviation Administration (FAA) Web camera images in Karluk also showed hazy conditions. AVO mentioned the resuspended ash event in the Friday, October 17, weekly update.\r\n\"The last ash resuspension event of 2014 occurred on Thursday, October 23, when strong winds resuspended 1912 volcanic ash and carried it southeast over Shelikof Strait, Kodiak Island, and the Gulf of Alaska. The ash was detected in satellite imagery, and the NWS issued Special Weather Statements, SIGMETs, and a Volcanic Ash Advisory. AVO \r\nincluded the ash resuspension event in its Friday, October 24, weekly update.\"","StartYear":2014,"StartMonth":5,"StartDay":19,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2014,"EndMonth":10,"EndDay":23,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Novarupta","ParentVolcano":"Novarupta","VolcanoID":"ak203","ParentVolcanoID":"ak203"},{"ID":851,"Name":"Pavlof 2014/5","Description":"From Cameron and others, 2017: \"The first eruptive episode at Pavlof in 2014 began at about 19:00 UTC (11 a.m. AKDT) on May 30, based retrospectively on a pulsating tremor-like signal in 1-5 Hz bandpass seismic data. The seismicity was visible across the Pavlof seismic network. By 07:22 UTC on May31 (11:22 p.m. AKDT, May 30), satellite data showed a strong thermal signal, suggestive of lava at the surface. AVO upgraded the Aviation Color Code and Volcano Alert Level from GREEN/NORMAL to ORANGE/WATCH at 19:36 UTC (11:36 a.m. AKDT) on May 31. Subsequent analysis indicated that the opening phase of the eruption on May 31 was recorded on an infrasound network on Akutan Island about 278 km (173 mi) southwest of Pavlof. AVO received the first pilot reports of ash emission on June 1, indicating distinct ash clouds as high as about 3km (2 mi) ASL, drifting north-northeast as much as 80 km (50 mi) beyond the summit of the volcano. Lahar (mud flow) signals were evident in seismic data from station PV6 by late in the day on June 1. These initial flows lasted for 15-30minutes each, and were preceded by sustained low-level pulsatory tremor.\r\n\"At about 01:30 UTC, June 3 (5:30 p.m. AKDT on  June 2) , the amplitude of the seismic tremor increased significantly; Web camera, satellite views, and several pilot reports all indicated that a period of robust ash emission was underway. At this point, AVO upgraded the Volcano Alert Level and Aviation Color Code from ORANGE/WATCH to RED/WARNING, where it remained for about the next 24 hours. During this period, the volcano erupted almost continuously, and observers in Cold Bay reported incandescence at the summit, seismic stations recorded lahar signals, seismic tremor remained at high levels, and strong thermal signals were evident in satellite data. The highest ash plume generated during this period of heightened activity reached as high as 6,700 m (22,000 ft) ASL (based on pilot reports) and extended about 100 km (60 mi) to the southeast over Sand Point and Unga Island. Although there were no reports of ashfall in nearby communities on June 2-3, significant SO2 emissions were detected in infrared atmospheric sounding interferometer (IASI) satellite data on June 3.\r\n\"Beginning at about 06:30 UTC on June 3 (10:30 p.m. AKDT on June 2), the overall level of seismicity began to decrease slowly, and at 01:54 UTC on June 4 (5:54 p.m. AKDT on June 3), AVO downgraded the Aviation Color Code and Volcano Alert Level to ORANGE/WATCH in response to the decreased levels of seismicity. Although the tremor level was reduced, the overall level of seismic activity remained relatively steady throughout the day on June 3, and was associated with a mostly steam-and-gas plume, containing only minor amounts of ash reaching as high as 5,900 m (19,600 ft) ASL and drifting to the south. Trace amounts of fine ash were reported at the Sand Point airport on June 3-4, resulting in cancelation of flights to Sand Point on the morning of June 4. As many as five flights to Cold Bay and nine flights to Dutch Harbor also were canceled on June 3-4 because of the risk of encountering ash. Local commuter air service was suspended as well during this time, affecting air travel to King Cove and False Pass. Flight cancellations continued into June 5, disrupting flights to and from Dutch Harbor and Cold Bay.\r\n\"The activity on June 2-3 was characterized by periods of vigorous lava fountaining that resulted in the accumulation of lava spatter on the upper northern flank of the volcano. This accumulation resulted in the formation of a spatter-fed lava flow that eventually extended about 4.7km (2.9 mi) downslope. At other times during the eruption, accumulations of spatter grew and built unstable piles of hot, fragmental material that occasionally collapsed and formed hot granular avalanches that flowed rapidly down the northern flank of the volcano for several kilometers. These hot granular rock avalanches swept across snow and ice, producing impressive steam plumes and generating melt water that led to the formation of lahars in some of the main drainages on the northern flank of the volcano. No ash or steam plumes were evident in satellite data after June 4, although seismic data recorded two explosions on the morning of June 5, and the World Wide Lightning Location Network (WWLLN) detected lightning near Pavlof from 10:16-10:59 UTC (2:16-2:59 a.m. AKDT) on June 5. Meteorological lightning is unusual in this part of Alaska, so the lightning likely was related to volcanic ash generated by the explosions. Emission of SO2 also was detected in OMI satellite data on June 5, and the SO2 plume extended from the volcano west about 100 km (60 mi).\r\n\"On June 6, the level of seismic activity decreased appreciably, relative to the previous several days. From June6-25, the level of unrest at the volcano continued to decrease further, and local observations of low-level lava fountaining were reported intermittently until about June 14. By June 25, satellite and Web camera data showed no evidence for lava fountaining or ash emissions. Only weakly elevated surface temperatures near the new lava flows on the northeastern flank were evident in satellite data. Consequently, AVO downgraded the Aviation Color Code and Volcano Alert Level to YELLOW/ADVISORY on June 25. By July 29 (AKDT) seismicity at Pavlof had returned to its normal background status and AVO downgraded the Aviation Color Code and Volcano Alert Level to GREEN/NORMAL.\"","StartYear":2014,"StartMonth":5,"StartDay":30,"StartTime":"19:00:00","StartQualifier":null,"StartQualifierUnit":null,"EndYear":2014,"EndMonth":6,"EndDay":25,"EndTime":null,"EndQualifier":10,"EndQualifierUnit":"Days","Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":4151,"Name":"Spurr 2014/6","Description":"From Cameron and others, 2017: \"A swarm of low-frequency earthquakes began in early June, following a M3.8 earthquake 13 km (8 mi) west of Mount Spurr. A total of 300 earthquakes were located in this swarm, which ended in mid-October. A swarm in the same area occurred in late 2012. The cause of the swarm remains undetermined. In 2004, seismicity, surface heat flux, and gas emissions suggested a magmatic intrusion (Power, 2004; Neal and others, 2005; Coombs and others, 2006).\r\n\"At 20:20 UTC (11:20 a.m. AKDT) on September 10, the Spurr seismograph network recorded a signal interpreted by AVO seismologists as a glacial outburst flood. The flow appears as a single event lasting about 20 minutes. Similar events, but of longer duration, have been recorded at Mount Spurr on several occasions, most recently in 2012 (Herrick and others, 2014). AVO was unable to visually confirm the inferred outburst event.\"","StartYear":2014,"StartMonth":6,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2014,"EndMonth":10,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Spurr","ParentVolcano":"Spurr","VolcanoID":"ak260","ParentVolcanoID":"ak260"},{"ID":861,"Name":"Cleveland 2014/6","Description":"After three months of no detected activity, an explosion occurred at Cleveland volcano at about 06:08 UTC, June 5, 2014, as detected on the Dillingham acoustic infrasound array and at seismic stations at Korovin Volcano. The event appears to have been of short duration and with similar amplitude to previous explosions at Cleveland. The Aviation Color Code and Alert Level remained at YELLOW/ADVISORY. No further activity was observed until weakly elevated surface temperatures seen in satellite data on July 7, 2014, and a vigorous steam and gas plume on July 8 and 9. In late July, 2014, clear satellite views showed persistently elevated surface temperatures in the summit crater, and typical gas and steam emissions. AVO field crews at Cleveland in August noticed typical steam and gas emissions from the summit. Elevated surface temperatures were again visible in satellite data in late August and early September. On September 11, AVO announced new monitoring capabilities at Cleveland: broadband and short-period seismometers, infrasound, and a webcam. Elevated surface temperatures and minor steaming continued at Cleveland throughout 2014. Satellite views in late November showed a small mound of lava in the summit crater, likely extruded around November 24, 2014. Seismicity remained at low levels.\r\nFrom Dixon and others, 2017: \"Cleveland began [2015] at Aviation Color Code YELLOW and Volcano Alert Level  ADVISORY and remained so for nearly 5 months. During this period, elevated temperatures were observed, as well as minor intermittent seismicity and steaming. At the volcano’s summit, the dome emplaced after the November 6, 2014, explosion remained the same size through February 2015. Elevated surface temperatures were observed in clear satellite images (fig. 22 [original text]). The diameter of the dome was about 45 m (150 ft) with an approximately 20 m (65 ft) depression that formed a shallow crater in the center. Incandescent fumaroles were detected on February 27 in cracks on the summit dome resulting from inflation of the dome. By March 27, satellite imagery confirmed growth of the dome to about 50 m (164 ft) in diameter (surface area 1,800 m2 or 19,000 ft2). \r\n\"After a sustained decline in eruptive activity over the span of a few weeks, Mount Cleveland was downgraded from Aviation Color Code/Volcano Alert Level YELLOW/ADVISORY to UNASSIGNED on May 28. Three weeks later, elevated surface temperatures returned, and a light dusting of ash visible on the upper flanks of Cleveland signified renewed activity. AVO increased the Aviation Color Code/Volcano Alert Level to YELLOW/ADVISORY on June 17 in response to this activity. Satellite imagery showed accelerated lava dome growth in the few days prior to raising the color code. The dome had increased to 55 × 85 m (180 × 280 ft) (outline area almost 3,900 m2 or 42,000 ft2). On July 21, the Aviation Color Code/Volcano Alert Level was elevated from YELLOW/ADVISORY to ORANGE/WATCH when an explosion at 16:17 UTC (08:17 AKDT) of similar amplitude as the explosion on November 6, 2014, at Cleveland was detected by the Cleveland infrasound array and ground-coupled airwaves on the Okmok seismograph network (fig. 23 [original text]). The explosion data, with no clear compression or rarefaction has been interpreted as a swelling and disruption of the conduit plug, followed by a more energetic 'uncorking' of the system (David Fee, UAFGI/AVO, written commun., 2015). This interpretation is similar to that for the previous explosion in November 2014. Satellite imagery showed that the lava dome was completely removed during this explosion and replaced by a small 40 m (130 ft) diameter crater. The hot summit vent surrounded by slightly cooler deposits likely from the July 21 explosion is shown in figure 24 [original text].\r\n\"On July 27 at 06:49 UTC (July 26 at 08:49 AKDT), a typical shallow subduction thrust earthquake of M=6.9 occurred about 80 km (50 mi) southeast from Cleveland. This earthquake was strictly tectonic and not related to the explosion at Cleveland, although many aftershocks were recorded on the Cleveland and neighboring seismograph networks.\r\n\"On July 30, strongly elevated surface temperatures were noted, consistent with dome growth after the explosion of the prior week. Two days later, on August 1 at 11:28 UTC (03:28 AKDT), a small airwave signal (40 times smaller than the July 21 explosion) in the region of Cleveland was detected, but was not considered a major explosion. Elevated surface temperatures were consistently observed in satellite imagery and a small steam plume was visible in the web camera following this small explosion. On August 4, AVO personnel overflew the summit of the volcano and observed a fresh lava dome forming that had a hot core (about 550-600 °C). Only \r\nminor degassing was detected during the flight. Images from this overflight are shown in figures 25A and B [original text]. \r\n\"A second explosion occurred on August 7 at 06:03 UTC (August 6, 22:03 AKDT) that was approximately one-half the amplitude of the July 21 explosion and much shorter in duration (1-2 seconds; fig. 26 [original text]). As viewed from satellite imagery, the lava dome that had been growing steadily since July 21 was only partially removed along its southern margin. On August 15, another overflight of the summit by AVO personnel showed more robust degassing and a dome with extrusions of partially new lava (\r\nfig. 25 [original text]; Werner and others, 2017). Satellite data from August 14 show that the 80m (262 ft) diameter lava dome deflated in the center and a 25-30 m (82-98 ft) diameter area of incandescent fractures across the dome surface was observed.\r\n\"August 29 marked the first notable earthquake swarm since the installation of a seismograph network on Cleveland in the summer of 2014 (fig. 27 [original text]). The swarm began around 19:03 UTC (11:03 AKDT) and continued for several hours before diminishing. This earthquake swarm was concurrent with elevated surface temperatures; however, nothing of note was recorded in the infrasound data. \r\n\"Elevated temperatures and minor steaming persisted for a few weeks following the two explosions. Strongly elevated temperatures decreased after July 30 and moderately elevated temperatures decreased regularly after that. This led to a lowering of the Aviation Color Code/Volcano Alert Level from ORANGE/WATCH to YELLOW/ADVISORY on October 14, and Cleveland remained at this level for the remainder of the year. Intermittent weakly elevated surface temperatures and minor steaming characterized the activity \r\nfor the latter months of the year. A summary of the eruption between 2011 and 2015 is shown in figure 28 [original text].\"","StartYear":2014,"StartMonth":6,"StartDay":5,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2015,"EndMonth":8,"EndDay":18,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":881,"Name":"Semisopochnoi 2014/6","Description":"From Cameron and others, 2017: \"Low-frequency events at Semisopochnoi Island were first noted on June 1, 2014. Semisopochnoi's seismic network had been returned to service on May 22, 2014, only 2 weeks prior to these events. The swarm began on June 9 at about 18:00 UTC (10:00 a.m. AKDT), and the AVO network recorded about 40 volcanic-tectonic earthquakes over the next 2 days. These earthquakes were small (less than M2) and clustered around Mount Cerberus in the center of the caldera. Depths ranged from 2 to 10 km (1.2 to 6.2 mi).\r\n\"Tremor was first noted on June 12, coincident with an increase in the rate of earthquakes recorded. Over the next day, the number of earthquakes doubled over the total located in the previous 3 days. The number of located earthquakes, all volcano-tectonic, doubled again on June 14, marking the peak daily earthquake count of the sequence (223 earthquakes). Throughout the increase in activity, the depth range of the events and epicentral area did not change. On June 13, AVO issued a VAN upgrading the Aviation Color Code and Volcano Alert Level to YELLOW/ADVISORY based on the ongoing swarm . Following the peak in earthquake activity on June 14, the number of located events decreased to 20-30earthquakes located in the last week of June, and further decreases in seismicity continued into July and August.\r\n\"On June 23, a M7.9 earthquake occurred in the region, 73 km (46 mi) west of Semisopochnoi Island at a depth of 118 km (73 mi) in the subducting slab. It was accompanied by more than 2,500 aftershocks, 60 with magnitudes of 4.0 or greater. There was no direct causality between the M7.9 earthquake and the Semisopochnoi volcanic-tectonic earthquake (VT) swarm; AVO did not note any change in the rate of VT seismicity at Semisopochnoi following the M7.9 earthquake.\r\n\"Zhong Lu of Southern Methodist University evaluated the deformation related to the volcanic unrest. More than 10 cm (4 in.) of inflation occurred between 2003 and June 26, 2014, about one-half of which occurred between June 15 and June 26, 2014. Maximum uplift was approximately in the center of the caldera. Modeled source depth ranges from 5 to 10 km (3 to 6 mi). (Zhong Lu, written commun., 2015).\r\n\"The consensus interpretation of the 2014 swarm is that it represents an intrusion of magma. This would be consistent with the style and character of the seismic swarm as well as the deformation signal. Although the seismograph network was not operational before May 22, the absence of significant activity between May 22 and June 9 suggests that the intrusion occurred in mid-June. An earlier pulse of magma possibly was emplaced before May 22, but without an operational seismograph network, this cannot be verified.\r\n\"In response to the swarm, AVO instituted heightened seismic watch schedules, requested that NOAA initiate HYSPLIT model ash cloud trajectory runs, and solicited pilots and the U.S. Coast Guard to report any unusual volcanic activity (such as steaming or ground cracks). Daily satellite analysis by AVO staff included careful examination of the volcano using all available imagery. Throughout the sequence, no surface activity was noted in the few clear-weather views of the island. The volcano is remote, and aerial reconnaissance by AVO staff was determined to be too costly to obtain.\r\n\"The 2014 unrest was the first significant departure from background at Semisopochnoi since installation of the seismic network in 2005. Background seismicity at Semisopochnoi had been relatively low (fewer than 50 earthquakes located per year until 2014), with short periods of weak seismic tremor. The last confirmed eruption at Semisopochnoi was from a satellitic vent in 1987 (Miller and others, 1998). The volcano, however, was deforming. Lu and Dzurisin (2014) discovered an area about 2 km (1.2 mi) in diameter that subsided during 2004-2010 at a rate of about 10 mm/yr (0.4in/yr). They suggested compaction of young volcanic deposits in the caldera as a mechanism to explain this subsidence; alternative hypotheses include localized subsidence due to depressurization of a shallow hydrothermal system or localized changes in the groundwater table.\"","StartYear":2014,"StartMonth":6,"StartDay":13,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2014,"EndMonth":8,"EndDay":4,"EndTime":null,"EndQualifier":1,"EndQualifierUnit":"Months","Volcano":"Mount Young","ParentVolcano":"Semisopochnoi","VolcanoID":"ak44","ParentVolcanoID":"ak248"},{"ID":4201,"Name":"Akutan 2014/7","Description":"From Cameron and others, 2017: \"A series of 34 earthquakes occurred on Akutan volcano on July 15, 2014. Nine of theearthquakes had a magnitude between 1 and 2; the rest were smaller. Following the earthquake swarm, AVO re-analyzed GPS data and concluded that Akutan experienced about 1 cm (0.4 in.) uplift around the time of the seismic swarm. The GPS data clearly show a volcanic inflation signal (outward and upward) with a start date at the beginning of 2014, most likely indicating intrusion of magma (Jeff Freymueller, UAFGI/AVO, written commun., 2014). A second earthquake swarm of 24 earthquakes occurred 5 months later on December 7, including a M2.5 earthquake, 2-3 km (1.2-1.9 mi) south of Akutan. Tectonic tremor was noted throughout 2014, and is typical for the Akutan seismograph network.\"","StartYear":2014,"StartMonth":7,"StartDay":15,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Akutan","ParentVolcano":"Akutan","VolcanoID":"ak6","ParentVolcanoID":"ak6"},{"ID":4191,"Name":"Chiginagak 2014/9","Description":"From Cameron and others, 2017: \"On September 30, 2014, AVO received an alert from the National Oceanic and Atmospheric Administration National Environmental Satellite, Data, and Information Service (NOAA-NESDIS) of elevated surface temperatures at Chiginagak volcano observed in MODIS and VIIRS satellite data . The thermal anomaly also was observed in AVHRR satellite data. Worldview data from July 31 and September 28 show no significant change in the summit crater; however, on September 29, AVO received a photograph of the northern flank of the Chiginagak volcano from a resident at lower Ugashik Lake, showing that the long-lived fumarole field on the northern flank had expanded several hundred meters downslope. After September 29, AVO received \r\nno new photographs or satellite observations indicating the presence of this expanded fumarole field, so it is uncertain how long this increase in heat flow persisted. This is the most extensive expansion of the fumarole field that has occurred in recent years, at least since the 2004-2011 field seasons, when repeated visits were made (see northern flank fumarole photographs, fig. 29, in Schaefer and others, 2013).\"","StartYear":2014,"StartMonth":9,"StartDay":29,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Chiginagak","ParentVolcano":"Chiginagak","VolcanoID":"ak49","ParentVolcanoID":"ak49"},{"ID":4181,"Name":"Martin 2014/10","Description":"From Cameron and others, 2017: \"Beginning on October 7, the AVO seismic network recorded an earthquake swarm centered roughly 15 km (9.3 mi) northwest of Mount Martin in an area where about 10 earthquakes per year are recorded. Twenty-six earthquakes were recorded on October 7, and, over the next 5 days, a total of 40 earthquakes were recorded. The largest earthquake in the swarm was a M1.8 on October 7. Seismicity in the Katmai region is dominated by earthquakes at volcanic centers; this swarm occurred in an established cluster of seismicity, closest to Mount Martin. The cluster of seismicity is dominated by shallow (less than 10 km [6.2 mi] deep) earthquakes with calculated magnitudes less than M2. No specific cause has been identified for the long-lived seismicity at this location.\r\n\"On November 24, observers in King Salmon emailed AVO about robust steam plumes rising about 300 m (about 1,000 ft) above Mount Martin. Observers reported that the plumes continued until the evening of November 25, after which they were no longer visible from King Salmon. These fumarolic vapor plumes are common at Mount Martin (McGimsey and Neal, 1996; McGimsey and Wallace, 1999; Neal and others, 2005; McGimsey and others, 2007; Herrick and others, 2014).\"","StartYear":2014,"StartMonth":10,"StartDay":7,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2014,"EndMonth":11,"EndDay":24,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Martin","ParentVolcano":"Martin","VolcanoID":"ak189","ParentVolcanoID":"ak189"},{"ID":971,"Name":"Pavlof 2014/11","Description":"From Cameron and others, 2017: \"Pavlof remained quiet and at background levels of seismicity until November 12, when seismic tremor increased sharply and increased surface temperatures were detected in satellite data, suggesting that lava had reached the surface. This was corroborated by reports of minor ash emissions and low-level lava fountaining from observers in Cold Bay. Observers also reported flows of rock debris and ash descending the northern flank of the volcano, and incandescence was observed in Web camera images. As a result of these observations, AVO upgraded the Aviation Color Code and Volcano Alert Level to ORANGE/WATCH on November 12.\r\n\"After November 12, the level of seismic activity continued to increase gradually and the thermal signal at the summit became persistently visible in satellite data. On November 13, satellite data showed a 200-km-long (124-mi-long) ash plume extending northwest of the volcano.Pilot reports estimated the ash cloud top at about 2,400-2,700m (about 7,900-8,900 ft) ASL. For the next 24 hours, all Pavlof seismic stations recorded nearly continuous seismic tremor, and satellite data showed strongly elevated surface temperatures, consistent with sustained lava fountaining. A narrow ash plume extending as high as 200 km (124 mi) from the volcano continued to be visible in satellite data, and information from passing pilots indicated that the ash plume eventually reached an altitude of about 4,800 m (15,700ft) ASL. Minor SO2 emissions were detected on November 14 in satellite data.\r\n\"On November 15, the intensity of seismic tremor increased significantly over a 6-hour period and satellite data indicated that the ash cloud, visible for the previous several days, had expanded and reached an altitude of about 7,600m (25,000 ft) ASL, and extended at least 200 km (124 mi) northwest of the volcano. In response to this increase in eruptive activity, AVO upgraded the Aviation Color Code and Volcano Alert Level to RED/WARNING. This plume eventually reached an altitude of at least 11,000 m (36,000ft) \r\nASL and extended about 385 km (240 mi) northwest of the volcano. Although the volcano was obscured by clouds, observers in Cold Bay reported rumbling and thunder-like sounds coming from the direction of Pavlof Volcano. Infrasonic tremor levels detected by the infrasound array in Dillingham increased steadily through the day on November 15 and were as high as, or higher than, infrasound levels recorded at any time during Pavlof’s May-June 2014 or 2013 eruptions (David Fee, UAFGI/AVO, written commun., 2014). The SO2 plume generated by this phase of the eruption extended west over the Bering Strait and into eastern Russia.\r\n\"Seismicity at the volcano decreased significantly on November 16 and remained at low levels, and ash plumes were not observed in satellite data thereafter. In response to thedecrease in seismicity and ash emission, AVO downgraded the Aviation Color Code and Volcano Alert Level to ORANGE/WATCH on November 16.\r\n\"Satellite observations indicated that eruptive activity ceased by about November 17. The intensity of thermal signals decreased gradually and the levels of tremor fluctuated slightly, but the overall amplitude decreased steadily. Thermal signals were occasionally observed in satellite datathrough November 26, but were the result of the still hot lava and debris on the northern flank of the volcano. As a result of the diminished levels of unrest, AVO downgraded the Aviation Color Code and Volcano Alert Level to YELLOW/ADVISORY on November 26, UTC (November 25, AKST). \r\n\"No further eruptive activity occurred at Pavlof Volcano in 2014, although unstable accumulations of cooling lava spatter occasionally collapsed, generating small ash emissions. The volcano gradually returned to normal background status, and on January 15, 2015, AVO downgraded the Aviation Color Code and Volcano Alert Level to GREEN/NORMAL.\"","StartYear":2014,"StartMonth":11,"StartDay":12,"StartTime":"15:00:00","StartQualifier":null,"StartQualifierUnit":null,"EndYear":2014,"EndMonth":11,"EndDay":17,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":4271,"Name":"Augustine 2015","Description":"From Dixon and others, 2017: \"Minor unrest occurred at Augustine Volcano in 2015 in the form of visible vapor plumes and rockfalls. In collaboration with Cascade Volcano Observatory (CVO), in June AVO installed a Multiple component Gas Analyzer System (MultiGAS) instrument at the summit of Augustine, designed to measure carbon dioxide (CO2), sulfur dioxide (SO2), and hydrogen sulfide (H2S). The Aviation Color Code/Volcano Alert Level remained GREEN/NORMAL throughout the year.\r\n\"Augustine has active fumaroles that often are visible under favorable atmospheric conditions. A gas measuring/sampling flight on April 3 detected low levels of water (H2O), CO2, SO2, and H2S, indicating that Augustine continues to degas at a low rate. The typical vapor plume at Augustine was often visible in web camera images during 2015, and was noted in satellite daily checks on January 25 and July 9. AVO received a PIREP of steam at Augustine on July 9.\r\n\"Twenty-two instances of rockfalls occurred at Augustine in 2015 as identified by emergent signals recorded on Augustine seismograph stations: this was twice the number of rockfalls reported in 2014. These rockfalls were concentrated during the months of June, July, August, and October. Rockfall signals at Augustine typically have an emergent onset and appear first at summit stations AUP and AUSS (fig. 5 [original text]). \r\n\"On June 12 and 13, AVO and CVO scientists installed a new, permanent MultiGAS/ seismograph station near the summit of Augustine. The MultiGAS instrument (fig.6) was designed and built at CVO, and includes sensors to intermittently measure CO2 and H2S. Data from these sensors are transmitted to AVO in near real time. A broadband seismograph station was installed near the MultiGas station at this time. Two months later another broadband seismograph station was added to the Augustine seismograph network.\"","StartYear":2015,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":991,"Name":"Semisopochnoi 2015/1","Description":"From Dixon and others, 2017: \"An increase in seismicity at Semisopochnoi was recorded in January 2015, characterized by numerous small earthquakes, most with magnitudes less than ML=1. The seismicity continued for several months and when tremor associated with the earthquake swarm appeared, AVO raised the Aviation Color Code/Volcano Alert Level from UNASSIGNED to YELLOW/ADVISORY on March 25, 2015. After a decline in the seismicity over a period of several months, the Aviation Color Code and Volcanic Alert Level were downgraded to UNASSIGNED on May 28. Throughout the earthquake swarm, no deformation or associated thermal anomalies were observed.\"","StartYear":2015,"StartMonth":1,"StartDay":null,"StartTime":null,"StartQualifier":14,"StartQualifierUnit":"Days","EndYear":2015,"EndMonth":4,"EndDay":null,"EndTime":null,"EndQualifier":1,"EndQualifierUnit":"Months","Volcano":"Mount Young","ParentVolcano":"Semisopochnoi","VolcanoID":"ak44","ParentVolcanoID":"ak248"},{"ID":4291,"Name":"Ugashik-Peulik 2015","Description":"From Dixon and others, 2017: \"On March 26 a ML=4.1 earthquake and aftershocks occurred close to the west shore of Becharof Lake in the same area as the 1998 Becharof swarm (McGimsey and others, 1999), 35 km (19 mi) west-northwest of Ukinrek Maars and 47 km (25 mi) west-northwest of Peulik. The earthquake series was short-lived as 17 earthquakes, 10 greater than ML=2.0, occurred within a 10-hour period, including the ML=4.1 and a ML=3.0 earthquake both of which occurred within the first 2 hours. These earthquakes formed a narrow east-west cluster 19 km (10 mi) in length at a depth of 7-9 km (3.7-4.9 mi). Nine additional earthquakes occurred in the same location in 2015-two in early March, five in mid-April, and two in late summer. The largest of these was a ML=3.2 on April 21, 2015.\r\n\"On July 15, an Alaska Department of Fish and Game (ADF\u0026G) biologist reported that the water in Hot Springs Creek, flowing from Ugashik caldera into Ugashik Creek was 'frothy and orange.' The biologist also reported that salmon were not entering the stream where Ugashik Creek flows into Ugashik Lake as in past years (fig. 9 [original text]). Two days after the report, two water samples were collected from Hot Springs Creek at locations shown in figure 9 [original text]. Analysis (table7 [original text]) showed a pH (5.76 and 5.52) similar to previous water samples collected in June 2004 (pH=5.71) by Evans and other (2009) in a similar location. An aerial survey of the creek from the caldera to Upper Ugashik Lake detected no orange discoloration of the stream beyond the caldera. Outside the caldera, the stream was not running clear, but appeared heavily laden with sediment, rather than tinted orange as with waters inside the caldera. No unusual activity was observed and the discoloration likely was caused by a period of high runoff that intermixed the thermal waters with the clearer water in the stream causing a temporary flow of anomalously colored water \r\nthat delayed the reported movement of salmon upstream by ADF\u0026G biologists. No volcanic unrest was apparent.\"","StartYear":2015,"StartMonth":3,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Ugashik-Peulik","ParentVolcano":"Ugashik-Peulik","VolcanoID":"ak295","ParentVolcanoID":"ak295"},{"ID":4281,"Name":"Novarupta 2015/3","Description":"From Dixon and others, 2017: \"High winds entrained and resuspended ash from Novarupta-Katmai 1912 on March 11, 2015, continuing into March 12, 2015. Alaska Airlines and Ravn Alaska cancelled flights into and out of Kodiak, due to high winds and ash. The ash was visible in satellite imagery, and strong winds were blowing from the Katmai area toward the southeast (fig. 7 [original text]). The National Weather Service Alaska Aviation Weather Unit (NWS AAWU) issued a Special Weather Statement. \r\n\"Four episodes of resuspended ash were observed during August through October. A multi-day ash resuspension event began on August 28, 2015, and continued through August 31, 2015. On August 30, the NWS issued a SIGnificant METeorological (SIGMET) information statement, and AVO mentioned the resuspended ash in its August 28 weekly update and issued a separate information statement on August 31. The ash was weakly visible in satellite imagery. Two ash resuspension events occurred in September-on \r\nSeptember23, with ash confined to altitudes less than 1,500 m (5,000ft) ASL, and another on September 29-30. \r\nResidents of Kodiak reported a fall of fine ash on the night of September 29-30, mixed with sleet and snow. AVO issued information statements on both occasions. The final ash resuspension event of 2015 occurred on October 29-30, when strong winds in the Katmai area again entrained loose 1912 volcanic ash and carried it east over Shelikof Strait and Kodiak Island. AVO again issued an information statement regarding the event.\"","StartYear":2015,"StartMonth":3,"StartDay":11,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2015,"EndMonth":10,"EndDay":30,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Novarupta","ParentVolcano":"Novarupta","VolcanoID":"ak203","ParentVolcanoID":"ak203"},{"ID":4301,"Name":"Kupreanof 2015/4","Description":"From Dixon and others, 2017: \"A mariner report of 'black smoke northwest of Ivanof Bay' was received at AVO on April 11, 2015. The probable source of the observation is Kupreanof Volcano where a known fumarolic field has persisted for decades (Yount and others, 1985b). Although reports from Kupreanof are uncommon, steaming from Kupreanof has been noted for at least the last 75 years and was last reported in the AVO annual summaries in 1994 (Neal and others, 1995). AVO took no further action on this isolated report.\"","StartYear":2015,"StartMonth":4,"StartDay":11,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2015,"EndMonth":4,"EndDay":11,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kupreanof","ParentVolcano":"Kupreanof","VolcanoID":"ak175","ParentVolcanoID":"ak175"},{"ID":4251,"Name":"Spurr 2015/7","Description":"From Dixon and others, 2017: \"No volcanic activity was reported at Mount Spurr in 2015; the only activity noted was an earthquake swarm 12 km (6.5 mi) north of the summit. First noted in the AVO internal logs in mid-October, earthquakes in this area occurred sporadically for the previous 5 months with the rate increasing from 1-2 per week in July to several per day in October. The swarm peaked in November, with 47 earthquakes during the month. The rate of located earthquakes decreased by one-half in December and the swarm continued into 2016 at a much-reduced level of activity. The earthquakes in this cluster were shallow with 90 percent occurring between 3 and 5 km (1.6 to 2.7 mi) below sea level. The Aviation Color Code and Volcano Alert Level remained at GREEN/NORMAL through the year at Spurr.\"\r\nIn 2016, there were four distinct clusters of seismicity at Spurr: \"the typical Mount Spurr summit earthquakes that occurred throughout the year, earthquakes near Pothole Glacier (west of Mount Spurr) in late summer, an ongoing swarm of low-frequency earthquakes 10–15 km (6–9 mi) north of the summit (north Spurr earthquakes in fig. 5), and a cluster of earthquakes located 5 km (about 3 mi) east of the summit in May (east Spurr earthquakes in fig. 5). In addition to these areas of high activity, there are three, less-distinct zones of activity. These zones are 10 km (6.2 mi) south, 5 km (3 mi) west, and 20–30 km (12–18.5 mi) northeast of Mount Spurr and are in the area of the 1996 Strandline earthquake (Kilgore and others, 2011). The Aviation Color Code and Volcano Alert Level remained at GREEN and NORMAL, respectively, throughout the year for Spurr.\" (Cameron and others, 2020).\r\nDixon and others (2020) report the seismicity at Spurr continued into 2017, including the unusual earthquake sequence that began in 2015. \"This cluster of low-frequency earthquakes (north Spurr earthquakes), was located 12 kilometers (km; 7 mi) north of Mount Spurr and continued to show activity throughout 2017. Although the character of the earthquakes is similar to glacial earthquakes, AVO has not determined a definite cause for this cluster of seismicity. The other four clusters (Mount Spurr summit, south Spurr, west Spurr, and the Strandline Lake earthquakes) are typical seismicity seen year-round in the vicinity of Mount Spurr (fig 2). An April 20 gas observation flight noted that the small plume emanating from the fumaroles in Spurr’s summit crater contained detectable quantities of SO2, H2S, and HCl. The Aviation Color Code and Volcano Alert Level remained at GREEN and NORMAL throughout the year at Mount Spurr.\"","StartYear":2015,"StartMonth":6,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2017,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Spurr","ParentVolcano":"Spurr","VolcanoID":"ak260","ParentVolcanoID":"ak260"},{"ID":4261,"Name":"Redoubt 2015/6","Description":"From Dixon and others, 2017: \"A significant amount of melt water was observed in late June, a suspected outburst flood from a subglacial meltwater reservoir in the Redoubt Volcano crater. Ground investigations determined the source of this outburst flood to be melt from a snow and debris avalanche, similar to those that routinely occur on Iliamna Volcano (fig. 4 [in original text]). A review of web camera views indicates this event occurred after June 28, and seismic evidence suggests a start at 03:54UTC (19:54 AKDT) June29. The source of the avalanche was a steep canyon wall immediately west of the 2009 dome. The avalanche is composed of multi-year snow and ice entrained with rock debris and fragmental products of the 2009 eruption. The Aviation Color Code and Volcano Alert Level were not changed due to this outburst flood and remained at GREEN/NORMAL through the year.\"","StartYear":2015,"StartMonth":6,"StartDay":29,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2015,"EndMonth":6,"EndDay":29,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Redoubt","ParentVolcano":"Redoubt","VolcanoID":"ak231","ParentVolcanoID":"ak231"},{"ID":1141,"Name":"Veniaminof 2015/10","Description":"From Dixon and others, 2017: \"Mount Veniaminof had a 2-month-long period of increased seismic unrest in 2015. At the end of September, seismicity at Mount Veniaminof increased in the form of volcanic tremor and small low-frequency earthquakes. This type of activity was a known precursor to previous eruptions, most recently in 2009 (McGimsey and others, 2014) and 2013 (Dixon and others, 2015). On October 1, after the activity persisted for 1 day, the Aviation Color Code and Volcano Alert Level were raised to YELLOW/ADVISORY. Throughout October and early November, clear views from the Federal Aviation Administration (FAA) Perryville northwest web camera occasionally showed minor steam plumes issuing from the intracaldera cone (fig. 11[original text]). The intermittent, short bursts of seismic tremor persisted into November, indicating continued unrest. At the end of November, the seismic unrest at Veniaminof decreased to near background levels. On December 11, the Aviation Color Code and Volcano Alert Level was lowered to GREEN/NORMAL.\"","StartYear":2015,"StartMonth":10,"StartDay":1,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2015,"EndMonth":11,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Veniaminof","ParentVolcano":"Veniaminof","VolcanoID":"ak301","ParentVolcanoID":"ak301"},{"ID":4741,"Name":"Okmok unrest 2016","Description":"From Cameron and others (2020): \"AVO seismologists noted seismic tremor at Okmok Caldera (herein called Okmok volcano to include associated volcanic features exterior to the caldera) in September 2016. This activity did not lead to significant unrest, and the Aviation Color Code and Volcano Alert Level remained GREEN and NORMAL, respectively. Tremor episodes began on September 19 and were frequently noted during the following week. Tremor episodes occurred at a rate of 5-10 per day and were detected on seismic stations within the caldera but not on those located outside the caldera. The locatable tremor episodes occurred in the east side of the caldera, and relative lag times suggested a source near Cone D. Although depths were not well constrained, they often seemed to be shallower than 5 km; however, occasional and more broadly occurring events seen across the network often had depths of greater than 25 km in the same region of the caldera.\r\n\"Inflation coincident with the tremor was not initially noted with the GPS network, but re-evaluation found a westward motion on GPS sites OKCE and OKNC. This motion is not consistent with the typical inflation signal at Okmok volcano (Jeff Freymueller, University of Alaska Fairbanks Geophysical Institute, written commun., 2017). Seismic and infrasound alarms were crafted for the volcano to assist with monitoring, but no further activity ensued. Pulses of tremor were sporadically noted through October, and by early November the instances of tremor were no longer observed.\"","StartYear":2016,"StartMonth":null,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Okmok","ParentVolcano":"Okmok","VolcanoID":"ak206","ParentVolcanoID":"ak206"},{"ID":4681,"Name":"Augustine unrest 2016","Description":"From Cameron and others, 2020: \"Minor unrest occurred at Augustine Volcano in 2016 in the form of a seismic swarm that began in February and continued intermittently into 2017. This swarm was similar to precursory seismicity observed at Augustine Volcano before previous eruptions, prompting increased surveillance on the Augustine data streams. The unrest did not result in eruption, and the Aviation Color Code and Volcano Alert Level remained GREEN and NORMAL, respectively, throughout the year.\r\n\"In 2016, there was a fivefold increase in the number of located earthquakes, totaling 836 for the year. The earthquakes were all located under the summit at shallow depths, 0–3 km (1–2 mi). Following a period of relative quiescence after the 2005–06 eruption, seismicity at Augustine Volcano increased slightly in 2012 when AVO located 54 earthquakes (fig. 8; Herrick and others, 2014). This activity continued to increase in 2013, 2014, and 2015 with 101, 127, and 162 earthquakes, respectively. The Augustine Volcano 2016 earthquake swarm began in February and continued at a high rate through the summer. A decrease in seismicity occurred during the fall and winter. Although the seismic activity looked much like precursory seismicity observed prior to the 1976, 1986, and 2005–06 eruptions, no eruption has yet ensued. No deformation or anomalous gas levels were noted in 2016.\r\n\"On January 24, the magnitude 7.1 Iniskin earthquake occurred at 10:30 UTC (1:30 AM AKST), between Augustine and Iliamna Volcanoes, and was the result of tectonic plate motions. This earthquake’s epicenter was about 27 km (17 mi) north of Augustine Volcano and 50 km (31 mi) south of Iliamna Volcano, at a depth of 122 km (76 mi). AVO did not detect any changes at either Augustine or Iliamna Volcano related to the earthquake.\"\r\nAnomalous seismicity continued in 2017. From Dixon and others (2020): \"The number of earthquakes located at Augustine Volcano in 2017 was abnormally high but was less than half (367) the number located in the previous year (836). The high level of seismicity was monitored closely and was determined not indicative of a pending eruption. A gas overflight in April was unable to make measurements of the plume, but on-ground measurements in July indicated that degassing activity remained at low levels. The Aviation Color Code and Volcano Alert Level at Augustine Volcano remained at GREEN and NORMAL, respectively, throughout the year.\"","StartYear":2016,"StartMonth":2,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Augustine","ParentVolcano":"Augustine","VolcanoID":"ak20","ParentVolcanoID":"ak20"},{"ID":4751,"Name":"Korovin unrest 2016","Description":"From Cameron and others (2020): \"AVO received a report of steam coming from Korovin Volcano on February 2, 2016, from an Atka, Alaska, resident (fig. 39). A check on seismic data revealed no evidence of any increased activity, and the steaming source was from an area near the volcano with known fumarolic vents that often steam (Motyka and others, 1993). Thus, the February report is considered part of typical Korovin Volcano activity. From April through August, multiple tremor bursts were noted in the seismograph data (fig. 40), and April and May recorded more tremor bursts than the later months. AVO kept the Aviation Color Code and Volcano Alert Level GREEN and NORMAL, respectively, for Korovin Volcano but maintained increased awareness and data checks during periods of increased tremor.\"","StartYear":2016,"StartMonth":2,"StartDay":2,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Korovin","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak171","ParentVolcanoID":"ak17"},{"ID":4731,"Name":"Makushin unrest 2016","Description":"From Cameron and others (2020): \"Earthquake swarms are common at Makushin Volcano, and nine short earthquake swarms occurred in 2016. Most swarms comprised fewer than two dozen earthquakes each. Prominent swarms occurred on February 7, April 12, August 26, September 21, September 24, November 15, November 27, and December 26 (fig. 26). During all of 2016, the Aviation Color Code and Volcanic Alert Level remained at GREEN and NORMAL respectively.\"","StartYear":2016,"StartMonth":2,"StartDay":7,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2016,"EndMonth":12,"EndDay":26,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":1151,"Name":"Pavlof 2016/3","Description":"From Cameron and others (2020): \"Pavlof Volcano erupted on March 27, 2016, about 500 days after the end of the previous eruption in 2014 (table 5). The March 27-28 eruption was a brief but intense eruptive event lasting about one day (fig. 16). This event generated minor ashfall at Nelson Lagoon 77 km (48 mi) northeast of Pavlof Volcano and trace ashfall at Port Heiden and Dillingham 263 km (164 mi) and 453 km (281 mi) northeast of Pavlof, respectively. More than a hundred flights were cancelled between March 27 and March 29 because of ash from the eruption. Two additional eruptive periods occurred in May and July 2016, but these events produced only small ash clouds and minor ash fallout confined to the upper flanks of the volcano. The March 28 eruption generated significant ash clouds reaching as high as 12.5 km (41,000 ft) ASL, and pyroclastic flows and lahars on the flanks of the volcano, one of which destroyed seismic station PV6 on the north flank of the volcano.\r\n\"The first indication of unrest in 2016 began with a late morning telephone call on March 25 from National Weather Service personnel in Cold Bay, Alaska, who reported a steam plume rising from the summit of Pavlof Volcano (fig. 17). Although steam plumes at Pavlof are common, this particular plume was reported as more robust than usual. A review of web camera images from a Federal Aviation Administration (FAA) web camera in Cold Bay showed a prominent steam plume visible from 17:47 until 19:57 UTC (9:47 to 11:57 AKDT), when it became obscured by clouds. No unusual seismic activity was noted on March 25 or the following day on March 26.\r\n\"The volcano remained quiet throughout most of the day on Sunday, March 27, and a relatively clear satellite view of the volcano summit above the cloud deck at 22:33:15 UTC (14:33 AKDT) showed no evidence of any unrest. At 00:18 UTC, March 28 (16:18 AKDT), an ash cloud reaching about 6 km (20,000 ft) ASL and moving north was reported by a nearby pilot. At about 01:33 UTC March 28 (17:33 AKDT March 27), AVO received a pilot report of ash emissions from Pavlof Volcano reaching an altitude of about 9.1 km (30,000 ft) ASL and observations of lava at the surface. Retrospective analysis of seismic data indicated that seismicity began to increase from background levels at about 23:53 UTC (15:53 AKDT) denoted by an abrupt increase in real-time seismic amplitude measurement (RSAM) levels and the appearance of continuous tremor on all operating stations of the Pavlof Volcano network. The tremor and RSAM levels observed on station PS4A illustrate seismicity during the eruption (fig. 18). At about 00:00 UTC March 28 (16:00 AKDT) tremor and RSAM levels continued to increase until about 06:38 UTC March 28(22:38 AKDT) after which the RSAM values leveled off but continued to fluctuate. At approximately 09:46 UTC March 28 (01:46 AKDT) they increased toward a peak value of 3200 and then began to decline in a saw tooth pattern until 20:40 UTC (12:40 AKDT) when the values fell to about pre-eruption levels (fig. 18).\r\n\"The abrupt increase in RSAM and tremor observed around 00:00 UTC March 28 (16:00 AKDT March 27) prompted AVO to raise the Aviation Color Code and the Volcano Alert Level to RED and WARNING at 01:12 UTC March 28 (17:12 AKDT), respectively. The rapid increase in seismicity is characteristic of several recent Pavlof Volcano eruptions, and it is not uncommon for the Aviation Color Code and the Volcano Alert Level to move from background status to the highest level with minimal precursory seismic activity.\r\n\"At 04:05 UTC March 28 (20:05 AKDT March 27), AVO received a pilot report of lava fountaining near the summit and a flowage feature on the north flank of the volcano. According to the pilot, the flowage feature had apparently reached the Bering Sea coast. The pilot referred to the feature as a pyroclastic flow, and it is possible that pyroclastic flows produced by collapse of the eruption column formed during the eruption. It is also possible that meltwater generated by the interaction of pyroclastic flows with snow and ice may have flowed well beyond the volcano to the north as lahars. The specific drainage containing the flow was not identified by the pilot, but lahars from previous historical eruptions have inundated both the Leontovich and Caribou River drainages on the north side of Pavlof Volcano.\r\n\"Pyroclastic flows or hot granular mass flows associated with collapse of spatter accumulations on the upper part of the edifice likely destroyed seismic station PV6 on the lower north flank of the volcano (fig. 19). Flowage signals were evident at PV6 starting about 01:06 UTC March 28 (17:06 AKDT March 27), and the station stopped transmitting 12 minutes later at 01:18 UTC March 28 (17:18 AKDT March 27).\r\n\"Satellite observations from 04:15 UTC March 28 (20:15 AKDT March 27) indicated that the ash cloud from the eruption extended 180 km (108 mi) northeast beyond the volcano over the Bering Sea (fig. 20). Ash cloud heights from pilot reports indicated a maximum altitude of about 9.1 km ASL (30,000 ft). By 15:10 UTC March 28 (07:10 AKDT), the Pavlof Volcano ash cloud formed a narrow, continuous plume that extended for about 885 km (550 mi) from the volcano over interior Alaska as detected in a Himawari-8 false color image (fig. 21).\r\n\"Ash fallout on March 27–28 was reported in several communities northeast of Pavlof Volcano, including Nelson Lagoon, Port Heiden, and Dillingham, Alaska. In Nelson Lagoon 77 km (48 mi) northeast of Pavlof, 3–17 millimeters (mm; 0.125–0.66 inches) of dark ash fell, covering roofs and surfaces (fig. 22). Trace amounts of ash (\u003c0.8 mm) were reported in Port Heiden and in Dillingham 263 km (164 mi) 453 km (281 mi) northeast of Pavlof Volcano, respectively.\r\n\"The March 27-28 ash plume caused the cancellation of 41 Alaska Airlines flights to and from Barrow, Bethel, Anchorage, Fairbanks, Kotzebue, Nome, and Prudhoe Bay, Alaska, on Monday, March 28, 2016. Regional flights operated by Bering Air were cancelled on the morning of March 28, PenAir suspended service to Dutch Harbor, Alaska, in the afternoon, and Ravn reported numerous flight cancellations (FOX59, 2016). Flight cancellations continued on Tuesday, March 29, and Alaska Airlines reported 28 cancelled flights to Barrow, Bethel, Kotzebue, Nome, and Prudhoe Bay, representing about 57 percent of Alaska’s flights to the most northern region it serves. Alaska Airlines additionally reported more than 6,200 travelers were affected on March 28 and 29 (Alaska Airlines, 2016).\r\n\"Lightning in the vicinity of Pavlof Volcano was reported by the WWLLN, which consisted of 16 lightning flashes detected over a 6-hour period between 13:10-19:13 UTC (05:10–11:13 AKDT) on March 28. Sulfur dioxide (SO2) emissions were detected by Infrared Atmospheric Sounding Interferometer (IASI) satellite sensors on the European Space Agency MetOp series of polar orbiting satellites on March 28 and 29. The SO2 cloud extended over interior Alaska and northwestern Canada (fig. 23) and eventually reached the southern Hudson Bay area of central Canada. The cumulative SO2 mass determined from the Ozone Mapping Profiler Suite (OMPS) satellite data obtained on 28 March was on the order of 20–30 kilotons (Simon Carn, Michigan Technological University, written commun., 2016).\r\n\"The March 28 Pavlof eruption was clearly recorded by infrasound instruments 453 km (281 mi) to the northeast at Dillingham (fig. 18). An infrasound signal was first evident at about 02:00 UTC March 28 (18:00 AKDT March 27), which corresponds to an emission time at the vent of about 01:40 UTC March 28 (17:40 AKDT March 27). The magnitude of the infrasound signals gradually rose until about 04:30 UTC March 28 (20:30 AKDT March 27) and then stabilized at high levels for several hours before declining significantly with no clear signals detected at Dillingham after about 21:00 UTC (13:00 AKDT) March 28 (David Fee, University of Alaska Fairbanks Geophysical Institute, written commun., 2016).\r\n\"By 20:40 UTC (12:40 AKDT) March 28, ash emissions were no longer evident in satellite data, and seismic activity had declined to nearly pre-eruption levels. AVO lowered the Aviation Color Code to ORANGE and the Volcano Alert Level to WATCH at 02:01 UTC (18:01 AKDT) March 29 because of the decline in robust eruptive activity.\r\n\"After March 28, 2016, unrest at Pavlof Volcano gradually declined. By April 6, 2016, ash emissions were no longer detected, and only weakly elevated surface temperatures associated with cooling deposits were observed in satellite data. At this point, AVO lowered the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY. Unrest continued to decline throughout the month of April 2016, and on April 22 AVO lowered the Aviation Color Code to GREEN and the Volcano Alert Level to NORMAL.\r\n\"Pavlof Volcano remained at background levels of unrest until May 13, 2016. At about 18:35 UTC (10:35 AKDT) May 13, seismic activity increased to levels commonly associated with low-level eruptive activity, suggesting that an eruption may have started. AVO responded by raising the Aviation Color Code to ORANGE and the Volcano Alert Level to WATCH at 20:04 UTC (12:04 AKDT) May 13. No volcanic activity was observed in satellite data or in web-camera views of the volcano on May 13. Minor ash emissions reaching as high as 6 km (20,000 ft) ASL were observed in images from the Cold Bay FAA web camera beginning around 03:46 UTC May 15 (19:46 AKDT May 14). Elevated surface temperatures were observed in satellite data on May 15, and SO2 emissions were detected in Ozone Monitoring Instrument (OMI) satellite data at 23:28 UTC (15:28 AKDT) May 17. AVO received several pilot reports of ash clouds rising to about 4.6 km (15,000 ft) ASL on May 17. This brief period of low-level eruptive activity lasted only a few days, and on May 20 AVO lowered the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY. After a few more weeks of no activity, AVO moved the Aviation Color Code to GREEN and Volcano Alert Level to NORMAL on June 17.\r\n\"The volcano remained quiet until July 1, 2016, when seismicity at the volcano began to increase, and minor steam emissions were observed in web-camera images. The increase in unrest prompted AVO to raise the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.\r\n\"Beginning around 21:00 UTC (13:00 AKDT) July 12 web-camera images showed minor ash emissions rising just above the roughly 2.6 km (8,500 ft) high summit vent and extending a few miles to the southwest. Clear satellite views of the volcano from about this same time showed no evidence of ash emissions or elevated surface temperatures, and there was no anomalous seismicity associated with this low-level activity. After July 12, Pavlof Volcano remained in a state of low-level unrest with occasional slightly elevated surface temperatures and minor steam and diffuse ash clouds observed. The Aviation Color Code remained YELLOW and the Volcanic Alert Level ADVISORY.\r\n\"On July 28, minor eruptive activity was observed in web-camera and satellite images of Pavlof Volcano and was characterized by vigorous, steam-rich degassing and minor ash emissions. Pilots also reported seeing ash emissions as high as 2.7–3.6 km (9,000–12,000 ft) ASL. These observations coincided with a minor increase in seismicity to levels high enough to warrant raising the Aviation Color Code to ORANGE and the Volcano Alert Level to WATCH at 19:55 UTC (11:55 AKDT) on July 28. Observations of minor steam and ash emissions as high as 2.4 km (8,000 ft) ASL were made by pilots on July 31. Only weakly elevated surface temperatures were observed on August 2, and by August 4 there was no further evidence of unrest at Pavlof Volcano. Thus, AVO reduced the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.\r\n\"Unrest at Pavlof Volcano remained slightly above background levels for about six months after early August 2016. Throughout this period, low-level steam and gas plumes from the summit and weakly elevated surface temperatures were observed occasionally when viewing conditions were favorable. The elevated surface temperatures were likely associated with still cooling pyroclastic deposits on the north flank of the volcano. By February 2017, unrest had declined to background levels although occasional, small, low-frequency events were observed in seismic data, consistent with an open, degassing system. AVO lowered the Aviation Color Code to GREEN and the Alert Level to NORMAL on February 2, 2017.\"","StartYear":2016,"StartMonth":3,"StartDay":27,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2016,"EndMonth":7,"EndDay":28,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":4711,"Name":"Aniakchak 2016 regional earthquake","Description":"From Cameron and others, 2020: \"Volcanic activity did not occur at Aniakchak volcano (an informal designation used by AVO to refer to the volcano that comprises Aniakchak Crater and the volcanic features in its vicinity) in 2016, but a magnitude 6.2 earthquake occurred 20 km east-southeast of Aniakchak caldera on April 2. This earthquake was followed by an energetic aftershock sequence, and most earthquakes were located in the upper 20 km of the crust. The earthquake and associated aftershock sequence were thrust events and nonvolcanic, although AVO seismologists closely monitored the activity in case a volcanic event was triggered by the regional earthquake sequence. The Aviation Color Code and Volcano Alert Level remained at GREEN and NORMAL, respectively.\"","StartYear":2016,"StartMonth":4,"StartDay":2,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":1161,"Name":"Cleveland 2016/4","Description":"From Cameron and others (2020): \"Mount Cleveland began 2016 at Aviation Color Code YELLOW and Volcano Alert Level ADVISORY after its August 7, 2015, explosion. A small lava dome emplaced after this explosion was still present at the beginning of 2016, and no changes to the dome were noted in the first few months of 2016 from satellite imagery. Minor steaming and weakly elevated surface temperatures were noted intermittently. The first explosion of 2016 occurred April 16 at 18:58 UTC (10:58 AKDT). In response, AVO raised the Aviation Color Code and Volcanic Alert Level to ORANGE and WATCH, respectively. This explosion was first detected by local infrasound sensors at seismograph stations CLES and CLCO, 3.5km (2.1 mi) and 15 km (9 mi) from the summit, respectively, and was the 40th explosion recorded at Mount Cleveland by AVO since December 25, 2011. Similar to most explosions at Mount Cleveland, the explosion had an impulsive onset and short duration (fig. 32). However, this explosion slightly differed from previous explosions by having a larger amplitude that exceeded the measurement scale of the local infrasound sensor CLES and was over 200 pascals at the CLCO infrasound sensor, 15 km (9 mi) away. The infrasound signal lasted more than 10 minutes at CLES, suggesting additional ash venting after the initial eruption. Retrospective analysis of geophysical data shows possible discrete precursory infrasound and seismicity beginning about 4 hours before the explosion (figs. 32, 33). Finally, there was a very long-period seismic signal at the time of the explosion. This is the first precursory and coeruptive seismicity noted by AVO at Mount Cleveland and the only instance in 2016.\r\n\"Vigorous steaming continued at the summit for about a week after the April 16 explosion. On April 18, satellite imagery showed that the upper northeast flanks of Mount Cleveland were covered with new tephra and ballistic blocks from the April 16 explosion. Subsequent satellite imagery also showed the lava dome was completely removed, and a 35-m-diameter vent, surrounded by a smaller tephra cone was visible. Because of no further eruptive activity, AVO lowered the Aviation Color Code and Volcanic Alert Level to YELLOW and ADVISORY, respectively, on April 29.\r\n\"A new, 30-m-diameter lava dome appeared in satellite imagery on May 5. Soon after this satellite observation, the second explosion of 2016 occurred on 2:43 UTC May 6 (18:43 AKDT May 5). The explosion was detected both by local and remote infrasound sensors, local seismic stations, and ground-coupled airwaves on the seismic networks of nearby volcanoes. This explosion was about half the seismic amplitude of the April 16 event. Unlike the previous explosion, no obvious precursory seismicity was observed. AVO upgraded the Aviation Color Code and Volcano Alert Level to ORANGE and WATCH respectively the same day in response to this eruption. A few days later, on May 10, another small explosion (three times smaller in infrasound amplitude than the previous explosion) occurred at 15:32 UTC (07:32 AKDT). The infrasound signal showed multiple compressions, likely attributed to slow destruction of the dome. Satellite imagery on May 11 confirmed that the early May dome was completely removed, leaving behind a shallow vent. New flowage deposits extending in several directions from the summit crater were also noted. A Landsat-8 image from May 15 shows robust steaming and high temperatures in the summit crater (fig. 34).\r\n\"Satellite views on May 18 showed a new, low-relief 50-m-(164-ft-) diameter lava dome centered in the summit crater. By May 21, the dome had grown to 60 m (197 ft) in diameter. Satellite images show recent eruptive deposits and the summit crater lava dome emplaced in mid-May (figs. 35, 36). Elevated surface temperatures continued after the explosion.\r\n\"At 22:05 UTC May 28 (14:05 AKDT), a small local earthquake swarm began and continued for almost 6 hours but did not culminate in an explosion. With no major activity observed, the Aviation Color Code and Volcano Alert Level were downgraded from ORANGE and WATCH to YELLOW and ADVISORY, respectively, on June 3. Elevated surface temperatures and minor steaming continued intermittently, and a 20-m- (66-ft-) diameter vent formed in the center of the summit dome between June 8 and June 17.\r\n\"An AVO field crew visited Mount Cleveland in late July to conduct network maintenance and collect gas samples of the plume. During a gas flight on July 26, a small dome, 46 m (151 ft) in diameter, with a crater in the center was observed (fig. 37). Forward looking infrared (FLIR) thermal camera images estimate the temperatures in the dome crater exceeded 600 °C, and incandescence was observed in the floor of the dome crater (fig. 38).\"","StartYear":2016,"StartMonth":4,"StartDay":16,"StartTime":"10:58:00","StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":1171,"Name":"Iliamna 2016/5","Description":"From Cameron and others, 2020: \"Members of the public noted typical amounts of steaming from the near-summit fumaroles at Iliamna Volcano, particularly in March 2016, and a large landslide occurred May 22. Iliamna remained at Aviation Color Code and Volcano Alert Level GREEN and NORMAL, respectively, throughout 2016.\r\n\"Radio station KSRM in Soldotna, Alaska, contacted AVO on Saturday, March 12, stating that people on the Kenai Peninsula could see 'quite a plume' coming from Iliamna Volcano. AVO noted no anomalous seismicity or evidence of increased steaming in satellite data. Web camera imagery showed white vapor and gas plumes rising from the volcano’s prominent and long-lived fumaroles. When Iliamna Volcano is backlit in the evening hours, as viewed from the Kenai Peninsula in spring and fall, its normal fumarolic plume often appears more prominent.\r\n\"At 07:58 UTC May 22 (11:58 pm May 21 AKDT), AVO detected seismic and pressure sensor signals associated with a large avalanche on the flank of Iliamna Volcano. Seismic signals from the avalanche were detected on volcano monitoring networks throughout Cook Inlet and as far away as the Mount Katmai area, 250 km (155 mi) southwest. The event was also recorded on distant infrasound stations in Dillingham, Alaska, 326 km (202 mi) and Fairbanks, Alaska, 610 km (379 mi) southwest and northeast of Iliamna Volcano, respectively. AVO issued an Information Statement about the landslide on Sunday, May 22. The sizeable avalanche covered about 7.2 km2 and extended down the east flank of the volcano (fig. 7; Dave Schneider, USGS, written commun., 2016)\"","StartYear":2016,"StartMonth":5,"StartDay":22,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":4101,"Name":"Cleveland 2016/10","Description":"From Cameron and others (2020): \"The final explosion of 2016 occurred at 21:10 UTC October 25 (13:10 AKDT). This explosion was detected by the local infrasound array and seismometers and was audible as far as Nikolski, Alaska, 74 km (44 mi) northeast of the volcano. AVO raised the Aviation Color Code and Volcano Alert Level to ORANGE and WATCH, respectively. Similar to previous explosions, most of the existing dome was removed, leaving a deep crater in its place. On November 4, the Aviation Color Code and Volcano Alert Level was lowered to YELLOW and ADVISORY, respectively, where it remained for the rest of the year despite intermittent observations of minor steaming and weakly elevated surface temperatures in the final two months of the year.\"","StartYear":2016,"StartMonth":10,"StartDay":24,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2016,"EndMonth":10,"EndDay":24,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":4721,"Name":"Frosty avalanche 2016","Description":"From Cameron and others (2020): \"Eruptive activity and volcanic unrest were not observed at Frosty Peak in 2016, but residents 15 km (9 mi) to the northeast in Cold Bay, Alaska, reported an avalanche to AVO on November 12. Cold Bay resident Michael Livingston sent AVO photographs of the avalanche and rockfall taken by Happy Kremer (fig. 24). These images show that a small part of Frosty Peak's bedrock spire collapsed and formed a prominent linear debris avalanche track across the snow.\r\n\"The Aviation Color Code and Volcanic Alert Level remained UNASSIGNED, because Frosty Peak is not seismically monitored by AVO and the avalanche was not initiated by volcanic activity. On November 14, AVO released an Information Statement about the event stating that, 'The collapse is not due to volcanic activity and was likely the result of the failure of unstable, altered, and weakened rock that makes up the summit of the volcano. Similar rock, ice, and snow avalanches have occurred previously at Frosty, most recently in 2001 (McGimsey and others, 2004).'\"","StartYear":2016,"StartMonth":11,"StartDay":12,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Frosty","ParentVolcano":"Frosty","VolcanoID":"ak105","ParentVolcanoID":"ak105"},{"ID":1301,"Name":"Bogoslof 2016/12","Description":"From Coombs and others (2019): \"Without a local seismic network, precursory seismicity was only recognized retrospectively. Wech et al. (2018) show that seismicity first occurred in September in the form of volcano-tectonic earthquakes, mostly on September 28-29 (swarm S1of Tepp et al. 2019). Wech et al. (2018) interpret these events as likely caused by magmatic intrusion into the middle to upper crust. A smaller earthquake swarm occurred in early October, with sporadic earthquakes continuing until the eruption in December (Tepp et al. 2019).\r\n\"From December 12 through March 13, explosions occurred at a mean rate of once every 58 h (2.4 days). Many of the explosions during this period were preceded by repeating earthquakes that accelerated into an explosion, characterized by increasing magnitude and becoming closer together in time, described by Wech et al. (2018) as 'slow-clap' seismicity and also described in Tepp et al. (2019) and Tepp and Haney (2019). On the basis of T-phase character, Wech et al. (2018) interpret these as occurring in the shallow crust.\r\n\"Seismicity remained at fairly low levels in October and November. In early December, days before the first detected infrasound, earthquakes with weak T-phases again suggested mid- to shallow-crustal magma movement (Wech et al. 2018). On December 12, the first infrasound signal from Bogoslof marked the beginning of the eruption. The signal, later recognized as event 1, was accompanied by a weak seismic signal, but no cloud was observed in satellite images. Infrasound for event 2, later the same day, has a relatively high frequency index (FI; ratio of high-frequency to low-frequency infrasound), suggesting a subaerial vent (Fee et al. 2019). On December 14, AVO received an email report from St. George, 308 km north-northwest of Bogoslof, about intermittent sulfur smell, likely corresponding to activity at Bogoslof. A Sentinel-2 satellite image taken minutes after event 3 on December 14 captured intense steaming from a subaerial vent and new pyroclastic deposits on the island and suspended in the surrounding ocean (Fig. 4a). Events 4 and 5 occurred on December 16 and 19. These first five explosions were not detected in real time, only after retrospective analysis of data streams. Thus, we have no direct observations of the character of these explosions.\r\n\"Satellite imagery beginning December 14 shows that uplift of Bogoslof Island occurred and may have been associated with cryptodome emplacement. A Sentinel-2 satellite image from December 21 (Waythomas et al. 2019a) shows an approximately 300-m long oval-shaped raised mass just north of Castle Rock (a remnant lava dome from the 1796-1804 eruptive period; see Fig. 3). This feature was not present in a Sentinel-2 image from December 14 (Waythomas et al. 2019a; their Fig. 5a). Preliminary analysis of DEMs generated by stereo satellite pairs shows that this feature continued to grow throughout the eruption (A. Diefenbach, written comm. 2019).\r\n\"No elevated surface temperatures were seen in satellite monitoring checks at Bogoslof until January 19, and neither the uplifted block nor surrounding areas were visibly steaming in December or January in a way that would be consistent with lava effusion (Figs. 3 and 6). Samples of the material exposed along the steep, eastward face of the uplift (see Waythomas et al. 2019b) are trachyandesite lava with 58-60 wt% SiO2 and are a different composition than the dominant juvenile basalt magma erupted in 2016-2017 (Loewen et al. 2019). Given the lack of thermal signature, as well as the composition of this feature, we suggest that this uplifted feature is likely the roof above a shallow cryptodome.\r\n\"Several pilots observed a volcanic cloud in the vicinity of Bogoslof on December 21 (Fig. 4b), and were the first alert to AVO that Bogoslof had become active. A pilot later the same day reported seeing 'a new land mass' in the island cluster. This event, event 6, began a period of activity that lasted a little less than a month, with explosive events 6-22 occurring at a rate of about one every 40 h. They produced volcanic clouds of heights up to 11 km, with variable durations (2 to 102 min), and about half produced detected lightning (Table 1). Most (80 %) consisted of single seismic pulses.\r\n\"Some of the only direct observations of activity occurred during event 9 on December 23, when observers aboard a Coast Guard vessel in the area reported ash emissions, lightning, and the ejection of incandescent lava and fragmental material that lasted about an hour. The cloud from event 16 on January 5 rose to 11.8 km asl and was observed by numerous pilots and mariners (Fig. 4c).\r\n\"A Worldview-3 image from December 25 (Fig. 6b) shows a bilobate submarine vent area and new pyroclastic deposits enlarging the island and beginning to enclose a vent lagoon. On December 29, data derived from US National Imagery Systems indicated a nearly complete ring of pyroclastic deposits around a more circular, submerged, ~ 450-m-across vent area. On January 10, passengers on a helicopter that flew from Dutch Harbor to Bogoslof took photographs and video of the island that showed discolored and roiling water in the crescent-shaped vent area, and the area of uplift from December (Fig. 3b). A Worldview-3 image from January 11 (Fig. 6c) shows continued growth of the island, and abundant meter-scale ballistics on the north and south ends of the island (Waythomas et al. 2019a, their Fig. 7).\r\n\"Satellite images, pilot reports, and ground-based photos show that event 23 on January 18 was the first demonstrably ash-rich cloud of the eruption sequence. Previous explosions produced clouds that were white in color with almost no ash signal in satellite data (Schneider et al. 2019).\r\n\"Prior to event 23, as with many other explosions on the first half of the eruption, seismic stations on neighboring islands picked up precursory seismicity in the form of repeating earthquakes that became more closely spaced in time during the runup to the explosion (Tepp et al. 2019). These lasted for about 11 h. Infrasound data show that the explosion itself lasted about 80 min and was pulsatory (Lyons et al. 2019b), with seven discrete bursts of strong seismicity (Searcy and Power 2019). Despite the event’s duration, only modest lightning was produced (14 strokes; Van Eaton et al. 2019).\r\n\"Pilots reports, visual satellite images, and thewest-facing FAA web camera in Dutch Harbor (Fig. 4d) indicated that the explosion produced a dark-gray ash cloud. MODIS satellite images show the cloud rose as high as 8.5 kmasl before drifting northeast over the Alaska Peninsula. An ash signal in the brightness-temperature-difference (BTD) satellite retrieval was seen along the leading cloud edge, suggesting that the cloud interior may have been opaque (Schneider et al. 2019). This event produced 1.9 kt of SO2 and was the first since event 13 on December 31 to produce more than 0.2 kt SO2 (Lopez et al. 2019).\r\n\"A mid-infrared MODIS satellite image collected minutes after the explosion showed a possible \"recovery pixel\". These occur when the sensor encounters a very hot object and saturates, suggesting lava or hot tephra must have been present above the water surface (D. Schneider, written comm. 2017). These were the first elevated surface temperatures detected by satellite imagery of the eruption. Clouds moved in to obscure the volcano soon after, with no additional views prior to January 20. Because event 23 was not detected on the Okmok infrasound array, we do not have infrasound FI analysis for this event, which for other events provides information on subaerial versus submarine venting (Fee et al. 2019).\r\n\"In the week following event 23, five explosions (events 24-28) occurred with an average repose time of 42 h between them (Table 1, Fig. 8). These events had total infrasound durations of 3-15 min, produced modest lightning, observable volcanic clouds, and each up to 0.6 kt of SO2 (Table 1). None showed a clear ash signature in satellite data.\r\n\"A Worldview-2 image acquired about 10 h after event 26 shows the island with a lagoon, open to the east, with two circular craters. The one to the northwest had upwelling within it, suggesting it was above the vent for the event 26 explosion (Waythomas et al. 2019a, their Fig. 8).\r\n\"About 84 h after event 28, the longest sustained explosion of the eruptive sequence produced significant ash and resulted dramatic changes to Bogoslof Island. Event 29 comprised more than 10 short-duration explosions that were detected in seismic, infrasound, and lightning data, took place over several hours on January 31, and produced several discrete volcanic clouds.\r\n\"The event started with no detected precursors, and activity escalated from 08:40 to 09:30, as indicated by increased seismic tremor and high amplitude infrasound signals. At 09:00, a continuous volcanic plume extended for a distance of more than 200 km towards the east-southeast over Unalaska Island at an altitude of 5.9 km asl. Event 29 produced 190 lightning strokes (Table 1; Van Eaton et al. 2019) and the most significant SO2 emission since December 22, 2016 (3.6 kt; Lopez et al. 2019).\r\n\"Tephra accumulation at the vent produced a demonstrably dry volcanic edifice for the first time during event 29. Data derived from US National Imagery Systems shortly after the event showed light steaming from an apparently dry eruption crater about 400 m in diameter and as much as 100 m deep below the west crater rim. Whereas most previous explosive events in the sequence, with the possible exception of event 23 on January 18, issued from a vent in shallow seawater, freshly erupted tephra formed an almost 200-m-wide barrier separating the vent from the sea. A Worldview-3 image from about 15 h later the same day (Fig. 6d) shows that the crater had already begun to fill with seawater. As with several of the events, large ballistic blocks were visible along the island’s north southwest shoreline (Waythomas et al. 2019a, their Fig. 9).\r\n\"Event 29 resulted in ashfall on Unalaska Island including trace (\u003c 0.8 mm) amounts in the community of Dutch Harbor/ Unalaska. A sample of ash collected in Dutch Harbor comprises free crystals of plagioclase, clinopyroxene, amphibole, and rare biotite, as well as particles that display a range of groundmass textures from microlitic to glassy, and that vary from dense to vesicular (Loewen et al. 2019). The material is consistent with being a mixture of juvenile basalt scoria and non-juvenile lithics.\r\n\"Following event 29, a series of smaller explosive events occurred from February 3 to 20 (events 30-36; Table 1). During this period, the inter-event times became more variable, with some pauses of up to 9 days between events. Explosions during this time lasted minutes to a few tens of minutes, produced clouds that rose from 4.6 to 8.6 km asl (Schneider et al. 2019), 0-92 strokes of lightning (Van Eaton et al. 2019), and modest SO2 (0-1.4 kt; Lopez et al. 2019).\r\n\"A series of satellite images from January 31 through February 12 shows little change in the island’s morphology after event 29 (Fig. 6d-e; Waythomas et al. 2019a). Elevated surface temperatures detected in two MODIS images from February 6 likely reflected hot new deposits from event 31 on February 4. A high-resolution Worldview-2 satellite image from February 23 also shows little change except for the presence of ballistics particles ejected during events 32-36 (February 13-20) and distributed across the island (Waythomas et al. 2019a). A clear view from March 3 similarly shows only minor changes (Fig. 6f).\r\n\"The final event in this time interval, event 36 on February 20, was an excellent example of a Bogoslof explosion with a precursory seismic sequence (see Fig. 4 of Coombs et al. 2018). A classic sequence of coalescing earthquakes served as a prelude to the series of energetic eruptive signals that made up the event. Earthquakes were first detected at 20:42 on February 19. The sequence then maintained a relatively low rate until about 00:55 (February 20) when the rate suddenly increased to about 30 earthquakes per hour. The rate then progressively increased over the next hour almost merging to tremor by 2:00. Earthquakes ceased at 2:07 and after a1-min break transitioned to tremor. The eruptive signals consisted of about 9 blasts that were captured on multiple infrasound arrays resulting in a 40-min long explosion. The resulting plume reached 6.1 km asl and was elongated, stretching to the east-southeast over Unalaska Island. Pilots and observers on Unalaska Island at the time clearly observed the white, ice-rich cloud (Fig. 4e).\r\n\"After a 16-day pause, event 37 on March 8 lasted 200 min. It had the largest infrasound energy (Lyons et al. 2019a), seismic tremor magnitude (Tepp et al. 2019), most lightning (1437 strokes; Van Eaton et al. 2019), largest SO2 emission (21.5 kt; Lopez et al. 2019), and most significant ash cloud (Schneider et al. 2019) of any event in the eruptive sequence (though not the highest reduced displacement; Haney et al. 2019a). VIIRS satellite images showed the resulting cloud reached between 10.6 and 13.4 km asl and drifted east over Unalaska Island. Minor ashfall of a few millimeters was reported by a mariner near Cape Kovrizkha (northwest Unalaska Island; Fig. 1) who collected ash from his vessel. Like the ash sample from January 31, this ash contains particles of juvenile basaltic scoria and free crystals with minor amounts of what appear to be volcanic lithics (Loewen et al. 2019). A barely perceptible ashfall deposit was reported at Unalaska/Dutch Harbor.\r\n\"Event 37 also changed the shape of the island and temporarily dried out the vent area, as seen in a Landsat-8 image from March 8 (not shown). In infrasound data, event 37 shows a mix of low and high FI, consistent with an eruption from both submarine and subaerial vent(s) during this event (Fee et al. 2019).\r\n\"A March 11 WorldView-3 image (Fig. 6g) shows the west coast of the island grew significantly since March 3 (Fig 6f), with about 250m of new land west of the 1926-1927 dome. A new ~ 150-m wide vent was also observed on the north coast of the island, and ballistics ejecta clustered on the eastern side of the island (Waythomas et al. 2019a, their Fig. 11).\r\n\"On March 10 and 11, two multi-hour seismic swarms each produced hundreds of earthquakes as detected on station MAPS (Tepp et al. 2019), but neither led directly to an explosion. A few hours later, a precursory swarm (Tepp et al. 2019) began on March 11 and culminated on March 13 in event 38. This event produced a small cloud that reached as high as 4.1 km asl and drifted south-southwest.\r\n\"Following event 38 on March 13, there was a 9-week pause in explosive activity at Bogoslof. The only detected unrest observed during the hiatus was a swarm of volcano-tectonic earthquakes on April 15. The swarm lasted for several hours, comprised 118 detected earthquakes (catalog of Wech et al. 2018) with magnitudes between ~ 0.8 and 2.2, and is interpreted to reflect magmatic intrusion in the mid to upper crust because of the earthquakes’ weak T-phases (Wech et al. 2018).\r\n\"Satellite images from this period show the rapid surface reworking and erosion of new volcanic deposits on Bogoslof Island and coastline erosion by wave action (Waythomas et al. 2019a). Photos (Fig. 5a) and a Worldview-3 image from May 11 (Fig. 6h) show that the vent lagoon remained hot throughout the hiatus, evidenced by steam rising from the crater lagoon.\r\n\"From May 16 through August 30, AVO detected 32 explosive events at the volcano. In contrast to the events of December 2016-March 2017, few of the explosions in the later phase were preceded by detectable seismic precursors, inhibiting AVO’s ability to forecast eruptive activity (Coombs et al. 2018), though retrospective analysis of hydrophone data showed that weaker precursors were still often present (Tepp et al. 2019). Fewer events produced detectable lightning after event 40 on May 28 (Van Eaton et al. 2019). This second phase also included effusion of two short-lived subaerial lava domes.\r\n\"After a nine-week hiatus, Bogoslof erupted without detectable geophysical precursors on May 17 (event 39). This explosion lasted 200 min and produced an ash cloud that reached as high as 10 km asl and drifted south along the edge of a mass ofweather clouds, as seen in GOES satellite imagery (Schneider et al. 2019) and reported by pilots. Trace ashfall (\u003c 0.8mm) was reported in Nikolski, Alaska, 123 km southwest of Bogoslof\r\n(Fig. 1). As with ash samples from the previous two events, this one contains about 40 % free crystals, though the remainder of this sample is richer in juvenile scoria (as opposed to lithic fragments) than previous ones (Loewen et al. 2019).\r\n\"Following event 39, an oblique photo showed that the crater lake was breached with a 550-m wide gap along the north shore and that the northeast shore was extended by another 300 m from new tephra deposits (Fig. 5b). Eleven days after event 39, explosive event 40 occurred on May 28, also with no detected precursors. This eruption produced an ash cloud that rose to 10.1 km asl as shown in MODIS satellite images\r\n(Schneider et al. 2019). The cloud drifted to the northeast and was reported by numerous pilots, including a report of 'sulfur' smell in cockpit from a plane about 800 km from Bogoslof. A Worldview-3 satellite image collected about 18 min after the start of the event shows the initial development of the eruption cloud (Fig. 4f; Waythomas et al. 2019a).\r\n\"These two explosive events, which occurred just after the hiatus, are among the most energetic of the eruptive sequence. They both produced appreciable SO2 clouds as detected in satellite data (9.4 and 7.7 kt; Lopez et al. 2019) and generated among the highest number of lightning  strokes (647 and 719; Van Eaton et al. 2019; Fig. 8). The remnant SO2 cloud from event 40 on May 28 was still detectable over Hudson Bay, over 4000 km east of Bogoslof, on June 2. Of the 25 events analyzed by Haney et al. (2019a), the co-eruptive tremor of these two events had the highest reduced displacement of any in the sequence-both yield values of about 50 cm2, which is comparable to values calculated for eruption tremor from the largest eruptions in Alaska over the past 20 years (e.g., Redoubt in 2009; McNutt et al. 2013).\r\n\"Cosmo SkyMed radar imagery from May 31 shows a large portion of the north side of the island was removed during May 28 explosive activity, leaving a crescent-shaped bay, open to the north. This configuration of the island remained essentially intact through June 12 (Fig. 6i).\r\n\"As seen previously from a March 8 Landsat image, sometime following May 28, intense steaming recommenced from an area just southwest of the vent lagoon. This region, about 300 m in diameter, remained hot and emitting steam throughout the eruption and afterwards (Fig. 6i-l), and may have been the site of shallow magma intrusion or a filled-in vent area.\r\n\"Early June brought a series of small explosions and growth of a lava dome that breached sea level on June 5, and was then destroyed on June 10.\r\n\"Several hours after a swarm of very small earthquakes on May 31, event 41 was a 5-min long explosion that produced a small, water-rich cloud that reached as high as 7.3 km asl. Following this, cloudy weather prevented clear views of the volcano through June 4. A Sentinel 1-B SAR image from June 4 shows no dome in the crater lagoon (Fig. 7a). Midday on June 5, data derived from US National Imagery Systems indicate that a small protrusion of lava had breached water level immediately between the 1926-1927 and 1992 lava domes in northern portion of vent lagoon. By June 6, low-resolution satellite images show distinctly elevated surface temperatures at Bogoslof, suggesting that hot lava was at the surface (Fig. 8). Sentinel-1 SAR images show the growth of the dome from June 7 through June 9 (Fig. 7b,c). On June 7, data derived from US National Imagery Systems showed that the new dome was about 110 m in diameter. The dome was also seen in a COSMO SkyMed radar image from June 8 (Waythomas et al. 2019a; their Figure 15).\r\n\"During the interval of lava effusion, several small explosive events (42-47) occurred that did not disrupt the growing dome as shown by Sentinel-1 SAR data from June 9, which confirmed that dome was still there after event 47 (Fig. 7c). Several of the events (44, 45, and 47) have infrasound frequencies consistent with a subaerial vent (Fee et al. 2019).\r\n\"The June 5 lava dome was short-lived, as it was completely destroyed during a long, pulsatory explosive event on June 10 (event 48). This event started with discrete explosions detected on the Okmok infrasound array as early as 8:27 but intensifying from 11:18 to 11:38. Starting at about 12:16, activity transitioned into nearly continuous seismic and infrasound tremor signals for about 40 min. Shorter bursts of tremor continued\r\nuntil 14:51, for an envelope of activity that lasted several hours. VIIRS satellite images of the resulting cloud showed it reached as high as 9.5 km asl and drifted to the northwest. Satellite data also indicated that at least part of the volcanic cloud was more ash-rich than many of those seen\r\npreviously in the Bogoslof eruptive sequence to date, suggesting that the eruption may have fragmented and incorporated the lava dome that was emplaced earlier that week (Schneider et al. 2019). This event generated 31 detected lightning strokes (Van Eaton et al. 2019).\r\n\"A Worldview-3 image from June 10, acquired after event 48, shows that the June 5 dome was no longer present (Waythomas et al. 2019a). Another, clearer Worldview-3 image from June 12 (Fig. 6i) showed ballistic blocks distributed uniformly around the island with the highest concentrations in the southeast and southwest sectors-likely remnants of the June 5 dome (Waythomas et al. 2019a). The FI of infrasound\r\nfrom this event gradually decreases in the last hour of the event, suggesting a change from subaerial to submarine venting after the destruction of the lava dome (Fee et al. 2019; their Fig. 8).\r\n\"On June 13, event 49 comprised a series of four explosions that started at 01:44 and ended at about 04:34. Each pulse lasted between 10 and 30 min and generated volcanic clouds that rose to a maximum height of 3.8 km asl and dissipated within about 30 min. Residents of Unalaska/Dutch Harbor reported smelling sulfur, and winds were consistent with a source at Bogoslof. An additional 2-min long explosion was detected in seismic and infrasound data later on 13 June (event 50), with no detected ash cloud.\r\n\"There was an 11-day pause in detected explosive activity from June 13-24. During an overflight on June 22, sediment-laden water was visible in the open vent lagoon area, and the area of persistent steaming was visible just east of the December uplift area (Fig. 5c).\r\n\"Twelve explosive events occurred from June 24 to July 11 (events 51-62). These were generally short-duration, detected in seismic and infrasound data, and produced little or no lightning (Table 1). Several of these events were closely spaced groups of smaller events. A photo taken on July 3 shows the area of persistent steaming visible from behind the December uplifted block, but no activity at other areas of the island (Fig. 5d).\r\n\"Following an almost month-long pause, explosive activity resumed on August 7, with a 2-h long sequence (event 63; Table 1). Detected in seismic, infrasound, satellite, and lightning data, event 63 was longer lived than many of the events in the eruptive sequence and satellite images showed that ash from the eruption formed a continuous cloud that was carried by strong winds south over Umnak Island and then out over\r\nthe Pacific Ocean reaching an altitude of 10-12 km asl (Schneider et al. 2019). Event 63 produced one of the largest SO2 masses of the eruption, 5.8 kt, as determined by IASI satellite (Lopez et al. 2019). It also yielded the highest number of lightning strokes during the second half of the eruption (117; Van Eaton et al. 2019).\r\n\"As shown in aWorldview-2 image from August 8 (Fig. 6j), event 63 produced significant proximal tephra that expanded Bogoslof Island’s northern coastline and closed off the northfacing lagoon to create a crater lake in the vent region, perhaps even leading to a subaerial vent for some portion of this explosive event. This image also shows a large number of new ballistic blocks, primarily in the east-southeast sector of the island (Waythomas et al. 2019a, their Fig. 18). In infrasound data, event 63 shows a progression from low to high FI, consistent with a shift from submarine to subaerial venting (Fee et al. 2019).\r\n\"The final 2 weeks of the eruption were marked by mostly short-duration explosions and concurrent growth of a lava dome. Events 64 through 70 were mostly short-lived (6 min or less, except event 70 which lasted 59 min; Table 1), produced little or no lightning (Van Eaton et al. 2019), and modest SO2 (up to1.2 kt; Lopez et al. 2019). Volcanic clouds from the explosions rose to high altitudes (up to 8.7 km asl; Schneider et al. 2019) despite their short durations.\r\n\"A high-resolution Worldview-3 image on August 13 shows a vent region filled with seawater and no lava dome was apparent (Fig. 6k). On August 15, repeating low-frequency seismic events from Bogoslof were detected on Okmok and Makushin networks for about 8 h (Tepp et al. 2019). A photo from an overflight of the volcano on August 15 shows the area of persistent steaming visible since late May, but nothing at the site of the dome that would appear days later in the vent lagoon (Fig. 5e). If the August 15 seismicity was related to magma ascent, it had not yet risen shallowly enough to impact the vent lagoon area.\r\n\"A new lava dome was observed in data derived from US National Imagery Systems in the enclosed, water-filled crater on August 18 and grew to about 160 m in diameter and 20 m tall by August 22. A Sentinel SAR view shows the dome on August 20 (Fig. 7d). An oblique aerial photo taken on August 26 shows a vigorous steam plume that likely was generated as hot dome rock interacted with seawater in the vent lagoon area (Fig. 5f).\r\n\"SAR images from Sentinel-1 (Fig. 7e) and Cosmos SkyMed (Fig. 7f) on August 27, after event 66, suggest that most of this dome had been removed, with only some northern dome edge remnants remaining. The low-frequency infrasound associated with events 66-69 suggest that the vent was below water (Fee et al. 2019).\r\n\"Following the last explosive activity on August 30, there were a few earthquakes detected in seismic and hydrophone data (G. Tepp, written comm. 2019), but seismic activity quieted soon after. In August 2018, AVO added a telemetered seismometer on Bogoslof Island, which has recorded little activity of note.\r\n\"Weakly elevated surface temperatures were consistently observed at Bogoslof in low-resolution satellite images through November 2017. High-resolution satellite images from the fall of 2017 show steaming and discoloration on the island (e.g., Fig. 6l). As of 2019, continued erosion has changed the shape of the island (Waythomas et al. 2019b), similar to what occurred following previous eruptions.\"","StartYear":2016,"StartMonth":12,"StartDay":12,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2017,"EndMonth":8,"EndDay":30,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Bogoslof","ParentVolcano":"Bogoslof","VolcanoID":"ak29","ParentVolcanoID":"ak29"},{"ID":1711,"Name":"Takawangha 2017/1","Description":"On January 24, 2017, citing an energetic earthquake swarm, AVO raised the Aviation Color Code and Volcano Alert Level at Takawangha from UNASSIGNED to YELLOW/ADVISORY. The earthquake swarm began January 23. The earthquakes located 6-7 km ESE of Takawangha Voclano. This activity could have been due to brittle failure in the surrounding rock caused by magma movement. No eruptive activity was detected in satellite imagery or other data. \r\nFollowing a significant decline in the energetic earthquake swarm, with seismicity returning to near background levels, AVO lowered the Aviation Color Code to GREEN and Alert Level to NORMAL for Takawangha volcano on February 8, 2017.","StartYear":2017,"StartMonth":1,"StartDay":23,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Takawangha","ParentVolcano":"Takawangha","VolcanoID":"ak277","ParentVolcanoID":"ak277"},{"ID":4111,"Name":"Cleveland 2017/2","Description":"From Dixon and others, 2020: \"Mount Cleveland began the seventh straight year at an elevated Aviation Color Code and Volcano Alert Level in 2017. Activity consisted of intermittent elevated surface temperatures, degassing from the summit cone, and the extrusion of small lava domes punctuated by explosions. Mount Cleveland began 2017 with fewer but similarly sized explosions to those in previous years that transitioned into more frequent but smaller explosions towards the end of the year...\r\n\"Mount Cleveland began 2017 at Aviation Color Code YELLOW and Volcano Alert Level ADVISORY. The last explosion on October 24, 2016, left a deep crater at the start of 2017. Activity in January consisted of intermittent gas plumes and elevated surface temperatures. By January 21, satellite imagery confirmed that a new lava dome partially occupied the summit crater. The dome measured 30 m (100 ft) in diameter on January 24, and by February 3 it was 70 m (230 ft) in diameter. The extrusion of this lava dome and potential for explosive activity prompted AVO to increase the Aviation Color Code to ORANGE and the Volcano Alert Level to WATCH on February 3. The dome ceased growing at 75 m (250 ft) in diameter around February 11 and remained unchanged into March, and weakly elevated surface temperatures and minor gas emissions were detected in satellite imagery and web-cameras during this time, consistent with cooling lava. After several weeks of inactivity, the Aviation Color Code and Volcano Alert Level was downgraded from ORANGE and WATCH to YELLOW and ADVISORY, respectively, on March 8. \r\n\"The first explosion of 2017, which occurred on March 24 at 16:15 UTC (08:15 AKDT), removed the lava dome. The short-duration explosion showed characteristics similar to previous dome-related explosions with a very sharp onset followed by about 10 seconds of additional signal in infrasound data. Cloud cover prevented the observation of ash cloud from this event. This explosion prompted the Aviation Color Code and Volcano Alert Level to be upgraded from YELLOW and ADVISORY to ORANGE and WATCH, respectively. \r\n\"On April 5, the Aviation Color Code and Volcano Alert Level was downgraded from ORANGE and WATCH to YELLOW and ADVISORY, respectively, because of inactivity since the explosion on March 24. Satellite imagery showed a new lava dome was extruded into the summit crater sometime before April 15 and by April 23 grew into a smooth 45-m- (150-ft-) diameter dome. The presence of a growing lava dome in the summit crater of Mount Cleveland prompted an Aviation Color Code and Volcano Alert Level upgrade to ORANGE and WATCH, respectively, on April 24. Extrusion of lava continued, and by April 28 three stacked domes had formed. The lowermost dome was 60 × 50 m (200 × 160 ft), the second dome 40 × 30 m (130 × 100 ft), and the newest and topmost dome was 15 m (50 ft) in diameter. The topmost circular dome continued to grow, and by May 2, it was greater than 20 m (65 ft) in diameter. Satellite imagery from May 8 showed no change in the size of the top dome, signifying that lava effusion had ceased at Mount Cleveland. \r\n\"On May 17, 03:17 UTC (May 16, 19:17 AKDT), an automated infrasound alarm indicated an explosion. A continuous broadband signal was recorded clearly in seismograph data and was also seen in infrasound data at stations CLES and CLCO for 10 minutes after the initial explosion. The extended infrasound signals were likely caused by jetting (continuous, vigorous gas emissions) after the destruction of the lava dome in the vent. The resulting ash plume drifted approximately 140 km (87 mi) to the southwest at an altitude of 4.6 km (15,000 ft) and was observed in visible Geostationary Operational Environmental Satellite imagery until nightfall. Satellite imagery just after the explosion showed that the dome was completely removed, and impact craters from ballistic dome fragments were formed on the upper flanks of the volcano. The Mount Cleveland summit crater was dome free through May 26. \r\n\"On June 6, a series of repeating small low-frequency seismic events were recorded on seismograph station CLES, 3.5 km (2.1 mi) from the summit, but these events were not seen on nearby seismograph station CLCO, 15 km (9 mi) from the summit. The seismicity was consistent with lava dome growth, but poor viewing conditions prevented the confirmation of dome growth. On June 26, the Aviation Color Code and Volcano Alert Level was reduced from ORANGE and WATCH to YELLOW and ADVISORY, respectively, owing to the decline in activity. \r\n\"On July 4, 11:19 UTC (03:19 AKDT), a moderate 10-minute eruption was detected by both seismograph and infrasound sensors, prompting the Aviation Color Code and Volcano Alert Level to be upgraded from YELLOW and ADVISORY to ORANGE and WATCH, respectively. This explosion differed from the previous explosion by being preceded by at least five low-frequency seismic events. Additionally, a burst of tremor was recorded 15 seconds prior to the onset of the main explosion.\r\nSatellite data from July 17 show that a new 25-m- (80-ft-) diameter lava dome was emplaced in the summit crater. It grew to more than 50 m (160 ft) in diameter with increased vertical inflation by August 1. Satellite imagery on August 7 showed no change in the lava dome from the previous satellite images, signifying that lava effusion had ceased. This small lava dome was observed by an AVO field crew during an overflight of Mount Cleveland on August 17.\r\n\"The fourth explosion in 2017 occurred on August 22 at 18:43 UTC (10:43 AKDT). The one-minute explosion had no precursory activity and was detected by both seismograph and infrasound sensors. Satellite imagery suggested that this explosion, like the previous three eruptions, removed the existing lava dome. The crater remained empty for more than a month until another explosion occurred on September 26, 01:47 UTC (September 25, 17:47 AKDT). The initial blast lasted 3 seconds, but after a brief 15-second pause, a roughly 2-minute-long broadband signal was detected in both seismic and infrasound data suggesting an initial vulcanian blast that was followed by continuous emissions. An ash cloud was visible in a NOAA-19 satellite image south of Mount Cleveland for 30 minutes after the explosion.\r\n\"The explosions later in 2017 were smaller and more frequent than those at the beginning of the year. Two small explosions occurred on September 28 at 13:19 and 13:58 UTC (05:19 and 05:58 AKDT, respectively) with amplitudes approximately 100 times smaller than the explosion 2 days prior. Another small explosion occurred on October 1, at 13:05 UTC (05:05 AKDT). \r\nSatellite observations on October 1 showed a new lava dome greater than 70 m (230 ft) in diameter, and by October 15, the dome had doubled in area to cover 12,500 square meters (m2;134,500 square feet [ft2]) at a height of 15-20 m (50-65 ft). The dome continued to increase in both area and height through October 23. On October 28, a small, short-duration (30 sec) explosion occurred at 18:45 UTC (10:45 AKDT). A smaller explosion occurred on October 30 at 11:20 UTC (03:20 AKDT). Satellite imagery suggests that the October explosions removed a portion of the central vent from the dome. A small explosion occurred on November 12 at 09:56 UTC (00:56 AKST) followed by a similar-sized explosion on November 14 at 12:15 UTC (03:15 AKST). The latter event was preceded by two local earthquakes 1 hour prior to the explosion. Another small explosion occurred on November 16 at 22:44 UTC (13:44 AKST) that was similar to the previous events. Between November 17, 22:00 UTC (13:00 AKST) and November 18, 08:20 UTC (November 17, 23:20 AKST), a small volcanic-tectonic earthquake swarm occurred in the vicinity of Mount Cleveland, but its significance to the Mount Cleveland eruption sequence has yet to be determined. A small explosion occurred on December 4, 07:21 UTC (December 3, 22:21 AKST) that was seen just at the closest seismograph station to the summit (CLES).\r\n\"Decreased activity following the December 4, 2017, explosion was interpreted as cessation of lava effusion at Mount Cleveland, which prompted AVO to change the Aviation Color Code and Volcano Alert Level from ORANGE and WATCH to YELLOW and ADVISORY, respectively, on December 12. However, less than a day later, another explosion occurred on December 13 at 13:20 UTC (04:20 AKST) necessitating that the Aviation Color Code and Volcano Alert Level to be returned to ORANGE and WATCH, respectively. The ash cloud from this eruptive event was visible in satellite imagery and drifted east at an altitude of 6.1 km (20,000 ft). The final explosion of 2017 occurred on December 18 at 03:17 UTC (December 17, 18:17 AKST), and like recent explosions was smaller than the explosions in early 2017. The Aviation Color Code and Volcano Alert Level remained at ORANGE and WATCH, respectively, for the remainder of the year.\"\r\nFrom Cameron and others, 2023: \"In addition to the preexisting volcanic activity alarms at Mount Cleveland, AVO implemented two new alarms in 2018 to help detect sudden explosions. One alarm uses the co-located seismic and infrasound sensors at station CLES to quickly detect smaller explosions, and the other uses seismic data in the very-long-period band from station CLCO. This second alarm became especially useful after CLES had an extended data outage starting in September 2018; for the latter part of the year, AVO had only CLCO to supplement the usual remote sensing techniques used to monitor Mount Cleveland. \r\n\"Mount Cleveland began 2018 at Aviation Color Code ORANGE and Volcano Alert Level WATCH, a response to its previous explosion on December 18, 2017, at 03:17 UTC (December 17 at 17:17 HAST). After several months without explosive activity, on February 9, 2018, AVO downgraded the Aviation Color Code and Volcano Alert Level to YELLOW and ADVISORY. The first explosion of 2018 took place on March 2 at 14:57 UTC (04:57 HAST) and was detected by AVO’s automated infrasound alarms. The acoustic amplitude of the explosion was similar to that of the previous explosion, and ground-coupled airwaves were detected as far as the Pavlof Volcano and Korovin Volcano seismic networks (747 km [464 mi] and 1,025 km [637 mi] away, respectively). A small volcanic cloud was observed in satellite data moving east-northeast shortly after the explosion. The event prompted AVO to raise the Aviation Color Code and Volcano Alert Level again to ORANGE and WATCH. After a few days with no substantial eruptive activity, on March 5, AVO downgraded the Aviation Color Code and Volcano Alert Level to YELLOW and ADVISORY. \r\n\"The next explosion took place on March 15 at 06:19 UTC (March 14 at 21:19 HADT) and was detected by the Mount Okmok infrasound array. The ground-coupled airwaves from this event were also detected by the Mount Okmok seismic network. Mount Cleveland produced another short-lived explosion on April 4 at 11:55 UTC (02:55 HADT), and possible jetting took place about 40 minutes later. In contrast to other explosions on Mount Cleveland, which typically have no notable precursory activity, a low-frequency seismic event preceded the April 4 explosion by about 19 hours. Satellite imagery taken after the explosion indicated the presence of hot material on the west flank from the summit down to the coast and a small volcanic cloud drifting at an altitude of about 19,000 ft (5,800 m) ASL. AVO upgraded the Aviation Color Code and Volcano Alert Level to ORANGE and WATCH in response to this explosion. Activity on the volcano declined after April 4, and on April 6, AVO downgraded the Aviation Color Code and Volcano Alert Level back to YELLOW and ADVISORY. Another small explosion took place on April 13 at 15:59 UTC (06:59 HADT). \r\n\"The next explosion at Mount Cleveland took place on May 5 at 06:08 UTC (May 4 at 21:08 HADT) and was detected by both the newly implemented seismic and acoustic alarms at CLES and by the previously running alarms on the CLCO infrasound array. A small volcanic cloud from the explosion, visible in satellite imagery, drifted southeast at an altitude of about 22,000 ft (6,700 m) ASL. In response to the event, AVO raised the Aviation Color Code and Volcano Alert Level to ORANGE and WATCH. After no new explosive activity, on May 6, AVO downgraded the Aviation Color Code and Volcano Alert Level back to YELLOW and ADVISORY. The event on May 5 was the last in Mount Cleveland’s first cluster of explosions in 2018. \r\n\"On June 3 and 9, two small swarms of local earthquakes took place near Mount Cleveland but did not appear to be associated with any explosive activity... Satellite imagery indicated that between June 19 and 25, a new lava dome measuring 80 m [260 ft] in diameter grew within the crater. The appearance of the dome prompted AVO to upgrade the Aviation Color Code and Volcano Alert Level to ORANGE and WATCH because the presence of lava over the active vent increased the possibility of a vent-clearing explosion. After a few months without explosive activity, on August 22, AVO downgraded the Aviation Color Code and Volcano Alert Level to YELLOW and ADVISORY. \r\n\"A data outage took place at the local monitoring station (CLES) on September 23 and persisted for the rest of the year, leaving the seismometer at the distal station (CLCO) as the only local instrumentation to supplement AVO’s remote sensing techniques. \r\n\"The second cluster of explosions to affect Mount Cleveland in 2018 began on December 10 at 08:55 UTC (December 9 at 22:55 HAST). The seismic amplitude of this first explosion, which was similar to that of previous explosions in 2018, triggered the seismic alarm at station CLCO. The seismic stations in the town of Nikolski, Alaska, and at Mount Okmok recorded ground-coupled airwaves. Satellite imagery taken after the explosion indicated that most of the summit lava dome was removed and that new debris flow deposits extended 2.6 km [1.6 mi] east-northeast of the summit. Another explosion took place on December 12 at 20:52 UTC (10:52 HAST), with an amplitude about 1.5 times larger than the previous explosion. The same day, AVO upgraded the Aviation Color Code and Volcano Alert Level to ORANGE and WATCH. \r\n\"The next explosion in the cluster took place on December 16 at 16:37 UTC (06:37 HAST). It triggered the seismic alarm and was also detected by the Mount Okmok seismic network in the form of weak, ground-coupled airwaves. This explosion was slightly larger than the previous one, producing a small ash cloud that reached an altitude of about 25,000-30,000 ft (7,600-9,100 m) ASL, possible SO2 gas emissions, and a single stroke of lightning (detected by the World Wide Lightning Location Network). Mount Cleveland produces volcanic lighting infrequently; its only other known occurrences took place in 2009 and 2014. The final explosion of Mount Cleveland in 2018 took place on December 29 at 03:17 UTC (December 28 at 17:17 HAST). A pilot weather report from after the explosion described an ash cloud reaching an altitude as high as 17,000 ft (5,200 m) ASL. Mount Cleveland remained at Aviation Color Code and Volcano Alert Level ORANGE and WATCH for the remainder of 2018.\" \r\nFrom Orr and others, 2023: \"Mount Cleveland was relatively quiet during 2019, producing only one small explosive eruption in early January. Despite the paucity of eruptions, its behavior otherwise was similar to that of previous years, with elevated surface temperatures and nearly continuous degassing from the summit that produced weak steam emissions. \r\n\"The volcano began 2019 at an Aviation Color Code and Volcano Alert Level of ORANGE and WATCH, having erupted a few days earlier on December 29, 2018. On January 7, 2019, after several days of quiescence, AVO downgraded the Aviation Color Code and Volcano Alert Level to YELLOW and ADVISORY. The volcano answered with a small explosion on January 9, recorded in local seismic and infrasound data. No associated plume was observed above the meteorological clouds, which reached an altitude of about 10,000 ft (3,000 m) ASL at the time. Later satellite imagery showed a thin tephra deposit extending southeast from the summit. AVO did not change the Aviation Color Code and Volcano Alert Level in reaction to this event. \r\n\"Satellite imagery taken on January 12 revealed the presence of a new dome 75 m [250 ft] in diameter, and by January 17, it had grown to 90 m [300 ft]. In response, AVO raised the Aviation Color Code and Volcano Alert Level to ORANGE and WATCH. The dome stopped growing soon after, and when no explosion took place, the Aviation Color Code and Volcano Alert Level were lowered back to YELLOW and ADVISORY on February 25.\"","StartYear":2017,"StartMonth":2,"StartDay":3,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2019,"EndMonth":2,"EndDay":25,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":4761,"Name":"Iliamna avalanche 2017","Description":"From Dixon and others (2020): \"Avalanches are common on Iliamna Volcano, and although no large debris avalanches were noted in 2017, small debris flows were observed. In March, a pilot noticed a debris flow feature on the west side of Iliamna Volcano (fig. 5). A second flow feature was fortuitously imaged by an AVO web camera in mid-April. A review of web-camera images shows the debris flow began on April 12 during the warmest part of the day, with more material moving downslope over a period of 6 hours (fig. 6). During an April 20 gas overflight, AVO observed minor snow and debris avalanche deposits on all flanks of the volcano. Despite complications from a south wind, successful gas measurements were obtained from the fumarole fields on the southeast side of the volcano indicating typical background-level emissions. The Aviation Color Code and Volcano Alert Level at Iliamna Volcano remained at GREEN and NORMAL, respectively, throughout the year.\"","StartYear":2017,"StartMonth":3,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":4121,"Name":"Pavlof 2017/6","Description":"The Aviation Color Code for Pavlof Volcano was raised to YELLOW on Wednesday, June 7 following an increase in low-frequency seismic activity and a pilot report indicating a possible ash cloud to 4000 ft asl. Active degassing from the summit was observed in web camera images and by local observers in Cold Bay yesterday and this morning. Infrasound data from local instruments on Pavlof and a more distant network in Sand Point show no evidence of significant explosive activity during the past week. Seismic activity has been at background levels since Thursday, June 8. Precursory activity leading up to previous explosive eruptions at Pavlof have been subtle and while some episodes of increased seismic activity have preceded eruptive episodes other increases have died back down without explosive activity.\r\n\r\nWeakly elevated surface temperatures and vapor plumes continued to be observed at Pavlof, but declined through June, July, and August. On August 30, 2017, citing normal, background levels of activity at Pavlof, AVO lowered the Aviation Color Code and Volcano Alert Level to GREEN/NORMAL.","StartYear":2017,"StartMonth":6,"StartDay":7,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2017,"EndMonth":8,"EndDay":30,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":4131,"Name":"Great Sitkin 2016/7","Description":"From the AVO Volcano Activity Notice of November 22, 2017: Recent observations of a robust steam plume and a period of gradually increasing seismicity over several months indicate that Great Sitkin Volcano has become restless and is exhibiting behavior that is above background levels. AVO is thus raising the aviation color code and volcano alert level to YELLOW/ADVISORY.\r\n\r\nPhotographs of the volcano taken by local observers on Sunday, November 19 show a light-colored vapor plume rising about 300 m (1,000 ft) above the vent area and extending about 15-20 km (9 -12 mi) to the south. Nothing unusual was observed in seismic or infrasound data around the time the photographs were taken and nothing noteworthy has been observed in satellite data since the emissions were observed. \r\n\r\nAn increased number of small earthquakes was evident as early as late July 2016, and since then the level of seismic activity has fluctuated at low levels but has exhibited a gradual overall increase most notable since June 2017. Seismic activity to date has been characterized by earthquakes that are typically less than magnitude 1.0 and range in depth from near the summit of the volcano to 30 km below sea level. Most earthquakes are in one of two clusters, beneath the volcano's summit or just offshore the northwest coast of the island. The largest earthquake so far was a magnitude 2.8 on September 29, 2017.\r\n\r\nPossible explosion signals were observed in seismic data on January 10 and July 21 of [2017] but no confirmed emissions were observed locally or detected in infrasound data or satellite imagery.\r\nAfter two months of declining seismicity, AVO lowered Great Sitkin to Green/Normal on January 18, 2018.","StartYear":2017,"StartMonth":6,"StartDay":30,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2017,"EndMonth":12,"EndDay":null,"EndTime":null,"EndQualifier":1,"EndQualifierUnit":"Months","Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":4844,"Name":"Shrub 2017/10","Description":"From Cameron and others, 2023: \"In the fall of 2017, a new eruption began low on the southeast flank of Shrub mud volcano, discharging a mud flow that wrapped around the south side of the base of the cone. This was the first new activity observed at Shrub mud volcano since the late 1990s and marked its first flank eruption since 1996, when a pilot reported seeing mud erupting from a vent low on the north flank of the volcano. Satellite imagery indicates that the 2017 activity began sometime between October 16 and October 20 and continued for several months, but given the poor quality of available imagery, it is equally likely that the event comprised two or more eruption episodes separated by pauses. A comparison between the mud flow extent visible in high-quality satellite imagery from June 2018 and helicopter overflight photos taken in June 2019 indicates that the eruption continued after June 2018.\"","StartYear":2017,"StartMonth":10,"StartDay":null,"StartTime":null,"StartQualifier":2,"StartQualifierUnit":"Days","EndYear":2018,"EndMonth":12,"EndDay":null,"EndTime":null,"EndQualifier":6,"EndQualifierUnit":"Months","Volcano":"Shrub","ParentVolcano":"Klawasi Group","VolcanoID":"ak253","ParentVolcanoID":"ak163"},{"ID":4331,"Name":"Shishaldin 2017/12","Description":"From Dixon and others, 2020: \"Shishaldin Volcano did not erupt in 2017, but volcanic unrest in December resulted in an elevated Aviation Color Code and Volcano Alert Level of YELLOW and ADVISORY, respectively, for much of the month. On April 20, AVO received a pilot report of an ash rich plume. Web-camera images confirmed the plume was composed of gas with no evidence of ash. Gas plumes are common at Shishaldin Volcano, and occasional reports of gas plumes and increased low-frequency seismic events were reported in AVO’s internal logs for most of 2017. \r\n\"In the last week of October, AVO noted elevated surface temperatures at the summit of Shishaldin Volcano. Throughout November, AVO observed increased low-frequency seismicity likely to be associated with small explosions. At the end of November, these explosions were being recorded on the infrasound array at Sand Point, Alaska, 230 km (140 mi) east of the volcano. In response to multiple signs of unrest, AVO elevated the Aviation Color Code to YELLOW and Volcano Alert Level to ADVISORY on December 6. Observations of degassing and energetic small explosions continued through December.\"\r\nFrom Cameron and others, 2023: \"The overall activity at Shishaldin Volcano declined throughout January 2018, and on February 7, 2018, this continued decline triggered AVO to lower the Aviation Color Code and Volcano Alert Level of the volcano to GREEN and NORMAL. No other notable unrest took place at the volcano for the remainder of 2018.\"","StartYear":2017,"StartMonth":11,"StartDay":null,"StartTime":null,"StartQualifier":14,"StartQualifierUnit":"Days","EndYear":2018,"EndMonth":1,"EndDay":null,"EndTime":null,"EndQualifier":30,"EndQualifierUnit":"Days","Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":4321,"Name":"Novarupta 2017/11","Description":"From Dixon and others (2020): \"On June 4, 2017, a National Oceanic and Atmospheric Administration (NOAA) and National Environmental Satellite, Data, and Information Service ash alert reported a possible resuspension event over the Valley of Ten Thousand Smokes (fig. 9). Atypical, easterly winds carried resuspended ash away from population centers so that an AVO Information Statement was not issued. AVO alerted the NWS Alaska Aviation Weather Unit * * * , \r\n\"Two ash resuspension events were detected in November, and the first was identified by a NOAA and Cooperative Institute for Meteorological Satellite Studies ash alert. On November 10, strong northwest winds over the Valley of Ten Thousand Smokes resuspended volcanic ash into a visible cloud and transported it eastward across Shelikof Strait and over Kodiak Island, where it was detected by the AVO particulate monitors at Larson Bay on the west coast of Kodiak Island. A similar sensor in the city of Kodiak, Alaska, on the east coast of Kodiak Island did not record any ash for this episode. AVO issued an Information Statement corroborating the hazard notifications issued by the NWS. By the evening of November 10, the resuspension event started to wane despite the surface winds continuing with gusts up to 20 meters per second (66 feet per second). A similar resuspension event occurred on November 13. The resuspended ash cloud extended 120 km (72 mi) to the southeast over the south end of Kodiak Island where no particulate monitors were installed. (fig. 10). AVO issued another Information Statement after the detection of this resuspension event.\"","StartYear":2017,"StartMonth":11,"StartDay":10,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2017,"EndMonth":11,"EndDay":13,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Novarupta","ParentVolcano":"Novarupta","VolcanoID":"ak203","ParentVolcanoID":"ak203"},{"ID":4847,"Name":"Pavlof non-eruptive activity 2018","Description":"From Cameron and others, 2023: \"The number of located earthquakes at Pavlof Volcano increased in 2018 compared to previous years. Although this increase was at least in part due to improvements to the local seismic network, there are indications that seismic activity in 2018 was nonetheless above background levels. Shallow LP earthquakes are common at the volcano, and the relative amplitudes of their waveforms, as observed by the Pavlof Volcano seismic network, indicate they tend to be located at or near the volcano summit. Although these events are commonly too small to be located by AVO’s routine earthquake location procedures, they are observable on spectrograms and are still noted in AVO’s routine seismic checks (Power and others, 2020). Similar activity has been observed at other open-vent systems in the Aleutian Arc, such as Shishaldin Volcano (Petersen and others, 2006; Pesicek and others 2018) and Mount Veniaminof (Pesicek and others, 2018), and appears to be typical for such systems (Quezada-Reyes and others, 2013). \r\n\"The Pavlof Volcano seismic network [in 2018] consists of three broadband digital seismic stations (PN7A, PS1A, and PS4A), three short-period 3-component stations (PV6A, PVV, and HAG), and one short-period vertical-component station (BLHA). The current configuration is fairly new; AVO carried out substantial upgrades to the network in the summer of 2017, during which PN7A, PS1A, PVV, and PS4A were upgraded to broadband digital stations, PV6 was replaced by PV6A, and HAG was upgraded from a vertical-component analog station to a 3-component station (Dixon and others, 2019). \r\n\"AVO located 152 earthquakes within a 20-kilometer radius of Pavlof Volcano in 2018...Throughout 2018, the volcano remained at Aviation Color Code GREEN and Volcano Alert Level NORMAL. Of the events that occurred in 2018, 111 were designated as LP earthquakes and 41 as volcano-tectonic (VT) earthquakes...Moderately deep LP earthquakes (10-20 km [6-12 mi] deep) took place in a broad swath east of Pavlof Volcano and Pavlof Sister throughout 2018, and although these events appear to be well-located based on reported root mean square errors (0.05-0.33), they often had small magnitudes. \r\n\"On March 27, 2018, an unusual cluster of VT earthquakes took place about 6-8 km [3.7-5 mi] north-northwest of Pavlof Sister and 12-13 km [7.5-8 mi] north of Pavlof Volcano. The earthquakes were 6.6-9.0 km [4.1-5.6 mi] below sea level with local magnitudes (ML) between 0.3 and 1.5. Later, in early April, a sequence of deep LP earthquakes took place near Pavlof Sister. These events were 10.1-29.3 km [6.3-18.2 mi] below sea level with ML values between −0.37 and 1.99, but only two events from the sequence were above ML 1.0. On September 11, another series of deep LP earthquakes took place in the same location as the March LP earthquake activity. The September 11 sequence had nine events, the two largest being ML 1.3 and 1.4. The hypocentral depths of these nine events ranged from 26 to 32 km [16-20 mi]. The sequence was also accompanied by a short tremor episode lasting about four minutes, though the tremor may have actually been closely spaced LP earthquakes. \r\n\"Volcano-tectonic earthquakes are not as common at Pavlof Volcano as at other volcanic systems, making the March 2018 brittle failure sequence notable. These events are assumed to have been distal VT earthquakes on the basis of their location (12-13 km [7.5-8 mi] from Pavlof Volcano), though they also may have been tectonically generated. AVO has not located any similar cluster in the same area since it began monitoring the volcano in 1996. The fact that there were more located events in 2018 than in previous years is not surprising given the network improvements made in 2017. Many of the 2018 events were of small magnitudes, and the increase in earthquake locations is partly due to the improved network. However, the additional presence of the March VT earthquake cluster and the LP earthquakes above ML 1.0 indicate the 2018 activity may have been above background levels for the upgraded network, suggesting increased magmatic activity at Pavlof Volcano in 2018. Alternatively, this behavior may be typical for the volcano but is only observed now because of the improved network. \r\n\"Observations made by Power and others (2004) of deep LP earthquake activity throughout the Aleutian Arc suggest a link between magma movement in the lower to middle crust and eruptive activity, although the timing between these parameters appears to vary. The deep LP earthquake activity at Pavlof Volcano may indicate the presence of continued magma supply to the volcano, with 2018 a slightly more active year. Further monitoring of earthquake activity at Pavlof Volcano will likely shed light on the magmatic system that feeds eruptive activity at the volcano.\"","StartYear":2018,"StartMonth":1,"StartDay":1,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2018,"EndMonth":12,"EndDay":31,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":4850,"Name":"Makushin unrest 2018","Description":"From Cameron and others, 2023: \"Makushin Volcano continued showing signs of unrest in 2018. After the eruption of nearby Bogoslof volcano in 2016-2017, reports of steaming from the summit of Makushin Volcano increased in frequency. The number of located earthquakes near Makushin Volcano has also increased since 2012. Despite these mild signs of unrest, no observations were enough to raise the Aviation Color Code or Volcano Alert Level, which remained at GREEN and NORMAL throughout the year.\r\n\"Steam emissions from Makushin Volcano were noted multiple times in the summer of 2018, both through webcam images seen by observatory personnel and in reports sent to AVO by residents of the City of Unalaska, Alaska. None of these reports differ in content from previous reports archived at AVO, which go back more than a decade. The increase in reports may be due in part to the activity at Bogoslof volcano, which could have prompted residents to forward more observations to AVO. \r\n\"Independent of the increased frequency of reports of steaming, AVO performed its first aerial summit gas survey at Makushin Volcano in the summer of 2018. Gas observations from the volcano’s gas plume yielded SO2 fluxes of ~100 t/d along with low CO2/Stotal (~1.5/2.5) and SO2/H2 S ratios (~1.1/1.7). These observations are consistent with degassing from a hot, mixed magmatic-hydrothermal system. The presence of SO2, a magmatic gas, has not previously been detected from ground-based measurements at Makushin Volcano, although it was also detected at the volcano by a new instrument, the TROPOspheric Monitoring Instrument on the Copernicus Sentinel-5 Precursor satellite, which launched in the fall of 2017. Until repeat surveys establish baseline data, however, the significance of this SO2 is unknown. \r\n\"The increase in seismicity that began in 2012 continued in 2018, with more than 1,000 earthquakes located by AVO near Makushin Volcano during the year. As is typical for Makushin Volcano seismicity, several short earthquake swarms were noted. Four of these clusters, which took place in the months of January, July, September, and November, were located 5-10 km [3.1-6.2 mi] southeast of the summit, making this area the most seismically active on the volcano. Three more swarms took place in January, March, and June, about 20 km [12.5 mi] to the northeast, southwest, and southeast of the summit, respectively.\"","StartYear":2018,"StartMonth":1,"StartDay":1,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2018,"EndMonth":12,"EndDay":31,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":4851,"Name":"Okmok non-eruptive activity 2018","Description":"From Cameron and others, 2023: \"In 2018, Mount Okmok (a name which herein includes associated volcanic features outside Okmok Caldera, such as Jag Peak and Tulik Volcano) continued the long-term reinflation that began immediately after its last eruption in 2008. This deformation takes place in discrete pulses that appear modulated onto a lower-rate, steady background deformation pattern. In 2018, monitoring stations OKCE and OKNC recorded a complete pulse, with a total horizontal displacement of about 10 centimeters (cm) [4 in] and a vertical displacement of as much as 12 cm [4.7 in]. Past analyses of geodetic data (GPS and InSAR) indicate a shallow magma reservoir exists underneath the caldera floor (for example, see Freymueller and Kaufman, 2010; Lu and Dzurisin, 2014), and the continued volcanic inflation is consistent with an ongoing accumulation of shallow melt. Mount Okmok’s Aviation Color Code and Volcano Alert Level remained at GREEN and NORMAL throughout 2018.\"\r\nFrom Orr and others, 2023: \"In 2019, Mount Okmok continued the long-term reinflation that began after its last eruption in 2008. This deformation takes place in discrete pulses that appear modulated onto a lower-rate, steady background deformation (for example, Xue and others, 2020). Like in 2018, a complete pulse took place in 2019 and was visible in the time series of monitoring station OKCE. The total displacement values were much less for the 2019 pulse, however, producing amplitudes of 4-5 centimeters (cm) [1.6-2 inches] in the horizontal and ~5 cm [2 in] in the vertical components. These are roughly half the amplitudes of the horizontal and vertical components recorded in the 2018 pulse. Past analyses of geodetic data (GNSS and InSAR) suggested a magma reservoir lies 2-3 km [1.2-1.9 mi] below sea level beneath the caldera floor (for example, Freymueller and Kaufman, 2010; Lu and Dzurisin, 2014), but more recent work suggests the existence of a shallow sill at 0.9 km [0.6 mi] and a pressure point source at 3.2 km [2 mi] below sea level (Xue and others, 2020). Regardless, continued inflation of the volcano is consistent with ongoing accumulation of melt at shallow depths. \r\n\"AVO scientists identified several seismic tremor episodes at Mount Okmok in September 2019. These began with a short tremor burst recorded on September 4 following observations of a few deep, low-frequency earthquakes on August 21 and 24. Several more tremor bursts were recorded on September 5. A series of longer (2-3 minute) tremor bursts took place on September 6, with bursts recurring every 10 minutes for about 90 minutes. AVO observed similar seismic activity again on September 9. The tremor episodes were not formally locatable, but the difference in tremor amplitudes between seismic stations suggests the tremor took place near cone A. Note that cone A and the other cones in Okmok Caldera have no formal names; the names used herein are informal. \r\n\"In addition to monitoring this activity through daily seismic checks, AVO implemented internal seismic and infrasound alarms to detect any increases in unrest. Satellite data showed no signs of unrest at Mount Okmok during these events, and the local infrasound array recorded no acoustic emissions. A retrospective analysis, however, found that the tremor onset coincided with a stop in the long-term inflation signal typically seen in geodetic data. Intermittent tremor bursts continued after the early September activity before finally subsiding in late November. The tremor bursts of 2019 did not lead to greater unrest, so the Aviation Color Code and Volcano Alert Level of Mount Okmok remained at GREEN and NORMAL throughout the year.\"\r\nFrom Orr and others, 2024: \"In 2021, Mount Okmok continued the long-term deformation trend that began immediately after its 2008 eruption. This deformation takes place as discrete inflationary pulses superimposed onto a lower-rate, steady background inflation and is consistent with ongoing accumulation of melt at shallow levels. One such pulse was recorded in 2021, appearing on the time-series plots for GNSS stations OKCE, OKNC, and OKSO. The total displacements of the 2021 pulse were similar to the totals of 2019 but larger than those of 2020 (see, for instance, the OKCE time series in figure 31 [in the original reference]), with amplitudes of 4-5 cm [1.6-2 in] in the horizontal and ~5 cm [~2 in] in the vertical components. This inflation is roughly half that of 2018, when the volcano underwent ~10 cm [~4 in] of horizontal displacement and as many as 12 cm [4.7 in] of vertical displacement (Cameron and others, 2023). \r\n\"From roughly the beginning of October through November 2021, Mount Okmok departed from its common deformation pattern by producing an additional inflationary pulse, prompting AVO to release an Information Statement. This pulse, which was observed at stations OKCE and OKNC, was consistent with a pressure increase at less than 1 km [0.6 mi] depth that had a source located near Cone D, south of Ahmanilix. Past analyses of GNSS and InSAR geodetic data suggest a shallow magma reservoir exists underneath the caldera floor of Mount Okmok (for example, Freymueller and Kaufman, 2010; Lu and Dzurisin, 2014).\"","StartYear":2018,"StartMonth":1,"StartDay":1,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2021,"EndMonth":12,"EndDay":31,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Okmok","ParentVolcano":"Okmok","VolcanoID":"ak206","ParentVolcanoID":"ak206"},{"ID":4852,"Name":"Gareloi 2018/06","Description":"From Cameron and others, 2023: \"The typical seismicity of Mount Gareloi is characterized by many low-frequency earthquakes that are commonly too small to be located by its seismic network, which comprises six stations on Gareloi Island and nearby Kavalga Island. Although the frequency of located seismic events varied in the past, seismicity at Mount Gareloi was fairly constant in recent years: 265 earthquakes were located in 2016 and 269 were located in 2017. In the summer of 2018, however, AVO located an anomalously high number of earthquakes, with 190 located in June and 178 in July. AVO then located 80 earthquakes in August and 77 in September before the volcano returned to typical activity levels in the fall. This period of increased activity was dominated by low-frequency earthquakes at depths of 5–15 km, which is typical for seismicity at Mount Gareloi. AVO paid close attention to the elevated seismicity rates but kept the Aviation Color Code and Volcano Alert Level at GREEN and NORMAL. \r\n\"In 2022, while retrospectively reviewing high-resolution satellite imagery of Mount Gareloi, AVO found a 2018 image showing an approximately 5-kilometer-long ash deposit extending north-northwest from the south fumarole field of the volcano. This image, taken by the WorldView-2 satellite on June 12, appears to record a previously unrecognized small ash emission (eruption). Satellite imagery acquired by Planet Labs PBC first shows the ash streak on June 6; the actual emission may have taken place on June 5.\"","StartYear":2018,"StartMonth":6,"StartDay":1,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2018,"EndMonth":9,"EndDay":30,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Gareloi","ParentVolcano":"Gareloi","VolcanoID":"ak106","ParentVolcanoID":"ak106"},{"ID":4845,"Name":"Spurr non-eruptive activity 2018","Description":"From Cameron and others, 2018: \"From June 6 to 9, 2018, AVO noted a sequence of seismic events on seismograph station STLK, located about 31 km [20 miles] east of Mount Spurr near Strandline Lake. This sequence was interpreted as glacial movement in the Strandline Lake area, but its precise source could not be located because only one station recorded the seismicity. The activity began on June 6 at 17:07 UTC (09:07 AKDT) with a series of weak, low-frequency earthquakes that increased in rate for an hour, at which point a 9-minute tremor-like signal was recorded (fig. 2). Earthquakes resumed after the tremor, and although they took place at a lower event rate, they also produced the highest amplitudes of the sequence. Earthquakes decreased in amplitude considerably over the next 9 hours, but weak earthquakes continued until 15:35 UTC (07:35 AKDT) on June 9. About 950 earthquakes were detected in the entire sequence, with 90 taking place prior to the tremor. This sequence was similar to previously described seismicity produced by weather-related glacial movements (for example, Thelen and others, 2013; Allstadt and Malone, 2014), and the earthquakes likely reflected stick-slip movement of the glacier, with the tremor burst produced by a period of continuous motion. Changes in the character of the earthquakes, including increasing durations, through the sequence indicate the seismicity source was changing over time - either in location or source conditions.\"","StartYear":2018,"StartMonth":6,"StartDay":6,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2018,"EndMonth":6,"EndDay":9,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Spurr","ParentVolcano":"Spurr","VolcanoID":"ak260","ParentVolcanoID":"ak260"},{"ID":4341,"Name":"Great Sitkin phreatic 2018","Description":"From Cameron and others, 2023: \"During 2018, AVO located more than 2,300 earthquakes at Great Sitkin Volcano, principally clustered in the shallow crust (extending from the summit to roughly 10 km [6.2 mi] below sea level). Additional earthquakes were also located between 15 and 35 km [9 and 22 mi] depth, with waveforms and frequency contents suggesting both VT and deep LP earthquakes. The magnitudes of these located events ranged from an ML of less than −1.0 to 2.48 - the largest event took place on August 31, 2018. Unfortunately, the Great Sitkin Volcano seismic network experienced several station failures in 2018, most importantly at stations GSTD and GSSP, which impaired AVO’s ability to locate earthquakes and resulted in the data gaps. The most notable of these failure periods spanned early November 2017 to mid-January 2018. Shorter-term failures of station GSSP also compromised AVO’s earthquake locating capabilities during the winter of 2018-2019. AVO identified several tremor bursts associated with this unrest during 2018, with most taking place between June and December. Interpreted as small explosion events, the tremor bursts contained a variety of waveforms with impulsive to emergent onsets, extended codas, and frequency between 1 and 15 hertz. The bursts were commonly associated with increased earthquake activity, but none produced infrasound signals identifiable by sensors in the nearby City of Adak, Alaska. The explosion of June 10, 2018, proved especially noteworthy when a Sentinel-2 satellite image acquired on June 11 at 23:00 UTC (14:00 HADT) showed a 2-kilometer [1.2 mile] long ash deposit extending southwest from the summit of Great Sitkin Volcano. Additional photographs of the summit area taken from a passing aircraft a week later showed an ash deposit on the snow. This deposit presumably came from the June 10 explosion. \r\nTo characterize the size and progression of the Great Sitkin Volcano explosions, AVO measured the durations of their signals using methodology described by Searcy and Power (2020). Tremor events lasting less than 2 minutes were excluded, though several took place during the unrest. For many of the signals, some uncertainty remains on whether they reflect explosions, short volcanic tremor episodes, or more minor steam bursts. Except for the event on June 10, which produced an identifiable ash deposit, any of these events could have been produced by any of the previously listed mechanisms. \r\n\"In response to the volcanic activity, AVO made four changes to Great Sitkin Volcano’s Aviation Color Code and Volcano Alert Level during 2018. The volcano began the year at YELLOW and ADVISORY, but on January 18, after the number of earthquakes had fallen to background levels, AVO lowered the Aviation Color Code and Volcano Alert Level to GREEN and NORMAL. It raised them again to YELLOW and ADVISORY on June 10 in response to the explosion signal that took place that day. The Aviation Color Code and Volcano Alert Level were lowered back to GREEN and NORMAL on June 27 after declining earthquake activity, then raised to YELLOW and ADVISORY again on July 1 as earthquake activity increased. Great Sitkin Volcano remained at YELLOW and ADVISORY for the rest of 2018.\"\r\nFrom Orr and others, 2023: \"On February 2 [2019], because of declining earthquake activity, the Aviation Color Code and Volcano Alert Level were lowered from YELLOW and ADVISORY, where they had been since July 1, 2018, to GREEN and NORMAL.\"","StartYear":2018,"StartMonth":6,"StartDay":10,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2019,"EndMonth":2,"EndDay":2,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":4846,"Name":"Iliamna avalanches 2018","Description":"From Cameron and others, 2023: \"Like in previous years, Iliamna Volcano experienced at least one large avalanche in 2018, as well as many smaller ones. The Aviation Color Code and Volcano Alert Level at the volcano remained GREEN and NORMAL throughout the year. Late in the morning of July 11, a resident from the Kenai Peninsula observed a fresh slide deposit on the east face of Iliamna Volcano. A retrospective analysis of seismic data indicated a probable avalanche signal at 00:24 UTC on July 11, 2018 (July 10 at 14:24 AKDT). The same resident observed a deposit from a slightly larger avalanche on August 1, 2018, but retrospective seismic analysis did not yield a possible signal for this later event. These deposits are very similar to those of Iliamna Volcano avalanches observed in prior years (Cameron and others, 2020; Dixon and others, 2020).\r\n\"On September 6, 2018, AVO measured the gas emissions at Iliamna Volcano during its annual overflight. These values proved largely unchanged from those of the previous year: instruments recorded an H2 S/SO2 value of about 2, a CO2 / (SO2 +H2 S) value of about 6, and an SO2 emission rate of 45±30 metric tons per day (t/d). The large uncertainty of the SO2 rate is due to a local wind field around the volcano that produces swirling air currents.\"","StartYear":2018,"StartMonth":7,"StartDay":11,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2018,"EndMonth":8,"EndDay":1,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":4441,"Name":"Veniaminof 2018/09","Description":"From Cameron and others, 2023: \"The 2018 eruption of Mount Veniaminof took place from early September to late December, ending a roughly 5-year repose since the end of its previous eruption in October 2013 (Dixon and others, 2015). Eruptive activity took place from a ~300-meter-high cone within the summit-defining, ice-filled caldera of Mount Veniaminof. All known historical eruptions have taken place at this cone, although only 5 of the 18 documented historical events produced lava flows. \r\n\"Seismic unrest at Mount Veniaminof began late on September 2, 2018. AVO responded on September 3 by raising the Aviation Color Code and Volcano Alert Level from GREEN and NORMAL to YELLOW and ADVISORY, and on September 4 raised them again to ORANGE and WATCH. Lava fountaining, which likely began as early as September 6, was underway by September 7. By September 14, a lava flow extended about 800 m [2600 ft] down the south flank of the summit cone. This flow eventually covered about 600,000 square meters (m2) [6.5 million square feet (ft2) or 0.23 square miles (mi2)], and intermittent ash emissions reached an altitude of 20,000 ft (6,000 m) ASL. Trace ashfall dusted nearby Perryville, Alaska, 35 km [22 mi] south of the volcano. \r\n\"More details of the 2018 eruption are published in Loewen and others (2022) and Waythomas and others (2022). Information about the 2018 eruption is derived from geophysical instrumentation on or near the volcano, including an 8-station seismic network, regional infrasound sensors, frequent satellite images of the eruption, occasional aerial photographs taken by passing pilots, and webcam images of the volcano from Perryville. Overall, eruptive activity consisted of occasional explosive emissions of ash and steam, episodes of lava fountaining, and the effusion of lava flows. Nearly continuous seismic tremor began at Mount Veniaminof late on September 2, and in response, AVO raised the Aviation Color Code from GREEN to YELLOW and the Volcano Alert Level from NORMAL to ADVISORY the next day. By the early afternoon of September 4, minor ash emissions were apparent in webcam images and were seen by observers in Perryville. This prompted AVO to raise the Aviation Color Code to ORANGE and the Volcano Alert Level to WATCH. \r\n\"Satellite imagery showed a trace amount of ashfall over the southwest sector of the caldera icefield. Webcam images obtained throughout the days of September 4-5 showed distinct, pulsatory ash emissions consistent with small Strombolian explosions. Diffuse ash emissions that reached an altitude of about 10,000-15,000 ft (3,000-4,600 m) ASL were observed by passing pilots on September 5. On September 7, incandescence was observed in early morning webcam images from Perryville, and mid-infrared satellite images showed strongly elevated surface temperatures at the intracaldera cone. These observations indicated that lava fountaining was underway by September 7, though initial lava effusion may have begun as early as September 6. Seismicity at the time was characterized by long-period events and pulsatory tremor bursts, the latter of which lasted as long as a few minutes, though it also included intermittent harmonic tremor (primarily on September 3). The tremor became more continuous around September 7. \r\n\"On September 11, a passing pilot observed and photographed several thin, ribbon-like lava flows, fed by low fountaining or spattering, on the south flank of Mount Veniaminof’s intracaldera cone and coalescing at the cone’s base. A WorldView-3 satellite image acquired on the same day showed lava erupting from as many as four small vents in the same area and feeding a lava flow covering about 50,600 m2 [545,000 ft2]. On September 16 and 18, Sentinel-2 satellite images showed definitive steam emissions associated with lava-ice interaction at the terminus of the lava flow, and on September 25, robust, vertically rising steam emissions associated with lava-ice interaction were evident in Perryville webcam images. Aerial photographs taken on September 26 confirmed that the lava flow had begun melting into the ice and snow on the south side of the intracaldera cone. Conspicuous concentric subsidence cracks grew around the periphery of the lava flow as the glacier responded to this melt-induced loss of mass. \r\n\"Sulfur dioxide emissions were detected near Mount Veniaminof on September 20, 24, and 25 by multiple satellite sensors. The volcano emitted about 500 metric tons (t) [~550 U.S. tons] of SO2 on September 25, whereas emissions detected on September 20 and 24 were barely above background levels. Regional seismic networks detected ground-coupled airwaves on September 25–27, indicating Strombolian explosions were taking place. On September 27, an infrasound array in Dillingham, Alaska (322 km [200 mi] north of the volcano), also recorded explosive signals from the volcano. \r\n\"Lava effusion characterized activity in early October and was associated with continuous tremor, nighttime incandescence, and persistent, strong thermal signals at the intracaldera cone. Measurements from the Ozone Monitoring Instruments (OMI) and the Infrared Atmospheric Sounding Interferometer (OMPS) detected sulfur dioxide emissions on October 4 and 10, but at amounts just above background levels (fig. 5). The total surface area of new lava flows by October 3, as determined from satellite data, was 184,000 m2 [about 2 million ft2]. \r\n\"Visibility improved considerably on October 18 compared to the previous several weeks, allowing a webcam in Perryville to record a billowy, low-altitude ash cloud extending southeast from the intracaldera cone. Several satellites detected SO2 on October 17 and 18, with OMI measuring about 270 t [300 U.S. tons] of SO2 emitted near Mount Veniaminof on October 18. Ash emissions reached an altitude of about 20,000 ft (6,000 m) ASL on October 19, and on October 23, satellite imagery showed minor ash deposits in the summit crater. Trace ashfall was reported in Perryville on October 25. Satellite observations that day indicated that lava had covered a total area of about 385,000 m2 [about 0.15 sqaure miles (mi2)]. The volcano remained restless through the end of October, with continued lava effusion and intermittent minor ash emissions. Sulfur dioxide was again detected in satellite data on October 30 and 31, but in amounts just slightly above background levels. \r\n\"By about November 3, activity at Mount Veniaminof began transitioning to episodic emissions of more robust steam and ash clouds, which appeared in satellite and webcam data. Satellite imagery from the early morning of November 5 showed an eastdrifting ash cloud, confirmed by a pilot’s observation, extending at least 60 km [37 mi] beyond the vent and reaching a maximum altitude of about 14,000 ft (4,300 m) ASL. From November 6 to 19, satellite data and occasional webcam images showed a persistent volcanic cloud of steam and ash extending as far as about 64 km [40 mi] from the intracaldera cone at an altitude that varied from 8,000 to 12,000 ft (2,400 to 3,700 m) ASL. Satellite instruments also detected SO2 near the volcano throughout early to mid-November, though the seasonal decline in ultraviolet light made the detection and accurate estimation of atmospheric SO2 loading less certain. \r\n\"On November 19, volcanic tremor increased in amplitude to reach the highest levels that had been measured up to that point in the eruption. This increase in seismicity was accompanied by infrasound detections on an array in Dillingham, which continued for the next few days. Satellite data from November 19 indicated that lava and tephra from the eruption now covered 540,000 m2 [0.2 mi2]. \r\n\"Conditions at the volcano escalated again on November 21, with increasing ash emissions and tremor amplitudes. An ash cloud detected in satellite imagery now extended more than 240 km [150 mi] southeast from the vent, reaching an altitude of at least 15,000 ft (4,600 m) ASL. This cloud was also observed from Perryville, where residents reported distinct \"booming\" sounds - likely explosions - coming from the direction of the volcano. The level of seismicity and the extent of the ash cloud prompted AVO to raise the Aviation Color Code and Volcano Alert Level to RED and WARNING. \r\n\"Mount Veniaminof emitted ash nearly continuously for much of November 21 as the ash cloud continued lengthening to the southeast, eventually reaching a distance of at least 400 km [250 mi] from the vent. Trace ashfall was again reported at Perryville on November 21 and 22. Activity began to decline by the late afternoon of November 21 (AKST), and on November 22, AVO lowered the Aviation Color Code and Volcano Alert Level to ORANGE and WATCH. Clear webcam views from Perryville on November 22 showed nearly continuous ash emissions extending as far as 100 km [62 mi] beyond the vent and reaching an altitude of about 10,000 ft (3,000 m) ASL. Unobstructed nighttime views showed incandescence at the summit.\r\n\"Coincident with a gradual decline in tremor amplitude, by November 25, ash emissions were no longer evident from the intracaldera cone. On November 27, however, the RSAM of volcanic tremor increased slightly, and AVO detected occasional infrasound pulses on arrays in the Alaskan cities of Dillingham, Sand Point, and Akutan. This slight increase in activity was associated with the appearance of minor ash emissions in satellite data. From November 30 to December 3, data transmission from the Mount Veniaminof remote seismic stations was interrupted, so AVO relied primarily on satellite observations and regional infrasound data to maintain surveillance. During this period, satellite data continued to show elevated surface temperatures, and small volcanic clouds were visible in some images. \r\n\"By December 6, the continuous tremor signal that had been characteristic of the eruption transitioned into frequent long-period (LP) earthquakes. This change likely indicated that lava effusion had paused or ended. Over the next several days, LP earthquakes and tremor bursts lasting as long as tens of seconds took place frequently, along with occasional harmonic tremor. A partly cloudy Sentinel-2 satellite image from December 10 showed that a light snow dusting covered parts of the intracaldera lava flows, and that only minor steam emissions continued. The weakening of seismic activity, absence of continuous tremor, and apparent cooling of the lava flows further indicated that eruptive activity had ceased. \r\n\"AVO detected many ground-coupled airwaves associated with LP earthquakes on December 11, but no other outward signs of unrest were observed in satellite or webcam imagery. This quiescence quickly changed as ash emissions from the intracaldera cone were again observed in Perryville webcam images on December 13 and 16. As cloud cover decreased over the volcano, satellite imagery again showed elevated surface temperatures, indicating a resumption in lava effusion, and also showed small volcanic clouds again extending from the intracaldera cone. This resumption of activity was accompanied by the return of the low-level, nearly continuous seismic tremor, which persisted until December 16, at which point the tremor signal ended and was replaced by many discrete, low-frequency events. Webcam images from Perryville showed minor ash emissions through December 17, after which the volcano was obscured by clouds. Satellite data confirmed that Mount Veniaminof emitted SO2 during the brief unrest in early to mid-December; additional SO2 emissions, possibly from the volcano, were also detected over the Seward Peninsula during this interval, about 966 km [600 mi] to the north. \r\n\"A Sentinel-2 satellite image acquired on December 20, 2018, showed no active lava effusion or additional advancement of the active lava flows. Slight fluctuations in seismic tremor amplitude took place from December 21 to 28, and on December 23, strong thermal signals again appeared in satellite data. From December 23 to 24, AVO observed lava-fountain-associated incandescence in webcam images. This activity was brief, however, and by December 27, all satellite, seismic, and webcam data indicated that active lava effusion had slowed, or perhaps stopped completely. From December 27, 2018, through the end of the year, the level of unrest at Mount Veniaminof gradually declined. \r\n\"By the end of the eruption, new lava flows covered 600,000 m2 [0.23 mi2] of land. This material came from a cluster of small vents on the upper south flank of a cinder cone within the ice-filled caldera. The flows melted into ice and snow, slowly creating melt depressions around their peripheries. However, no unusual water outflows were observed exiting the caldera through its main drainage, located northwest of the cone. The amount of lava and ash erupted from September 7 to December 27, 2018, resulted in the generation of about 1,200,000 cubic meters (m3 ) [42.4 million cubic feet (ft3)] of lava and 20,000-30,000 m3 [706,000-1,06,000 ft3] of ash, though no aircraft reported encountering ash throughout the eruptive period.\"\r\nFrom Orr and others, 2023: \"The activity at Mount Veniaminof during 2019 was mostly associated with a prior eruptive period that took place from early September to late December 2018 (Cameron and others, [2023]). Unrest at the volcano declined gradually after this period until it seemed likely that the eruption had paused or ended. On January 4, 2019, AVO lowered the Aviation Color Code and Volcano Alert Level from ORANGE and WATCH to YELLOW and ADVISORY.\r\n\"Satellite imagery showed slightly elevated surface temperatures on Mount Veniaminof throughout 2019, although cloud cover frequently impeded observations. The elevated surface temperatures were probably associated with the cooling of lava flows emplaced on the intracaldera cone in 2018 (Cameron and others, 2023). Minor steam emissions were occasionally visible in webcam views from nearby Perryville. Seismicity indicative of minor unrest - primarily low-amplitude tremor and discrete events - continued into April 2019 before finally declining to background levels. AVO lowered the Aviation Color Code and Volcano Alert Level to GREEN and NORMAL on April 30, 2019, after about four months with no significant unrest.\"","StartYear":2018,"StartMonth":9,"StartDay":4,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2019,"EndMonth":4,"EndDay":30,"EndTime":null,"EndQualifier":4,"EndQualifierUnit":"Months","Volcano":"Veniaminof","ParentVolcano":"Veniaminof","VolcanoID":"ak301","ParentVolcanoID":"ak301"},{"ID":4471,"Name":"Semisopochnoi 2018/09","Description":"From Cameron and others, 2023: \"Activity at Semisopochnoi Island, in the Rat Islands, Alaska, began in September 2018 and continued through the fall. It was characterized by sporadic, weak eruptive activity from the north cone of Mount Young. Though seismic tremor and explosion signals captured most of this activity, AVO also made infrequent infrasound detections and satellite observations of steam emissions and small ash deposits. Retrospective analysis showed that activity continued through the end of the year, but real-time observations were limited by a prolonged data outage beginning November 1, 2018. \r\n\"The first activity detected at Mount Young in 2018 included two minor seismic bursts on September 8 at 08:10 and 09:44 UTC (September 7 at 22:10 and 23:44 HADT). This seismicity was preceded by weak tremor beginning on August 25, but AVO only recognized the tremor during retrospective analyses. Satellite imagery taken during the summer showed a seasonal lake within the crater of the north cone on Mount Young, but satellite imagery from September 4 showed the crater steaming, and satellite imagery from September 5 showed the lake to be three times larger than normal. On September 10, ash deposits extending about 1 km west of the north cone were visible in satellite imagery, and within the crater, AVO noted a new tephra cone about 75 m [250 ft] in diameter. \r\n\"Seismicity increased on September 16; strong tremor beginning at 16:31 UTC (07:31 HADT) caused AVO to raise the Aviation Color Code and Volcano Alert Level from GREEN and NORMAL to YELLOW and ADVISORY. The lake in the crater dried up around the same time, and on September 15 and 17, AVO observed fumaroles and steam in satellite imagery. On September 17, an increase in seismicity and tremor strength, in addition to the recognition of the ash deposit in the September 10 satellite image, led AVO to increase the Aviation Color Code and Volcano Alert Level again to ORANGE and WATCH. \r\n\"From September 16 to 29, seismicity alternated between continuous tremor and tremor bursts. At the same time, atmospheric propagation conditions improved between Semisopochnoi Island and the infrasound array on Adak Island (a 13-minute delay), leading to the first infrasound explosion detection on September 21. Satellite imagery indicated weakly elevated surface temperatures on September 19 and the presence of steam on September 20. Tephra deposits were seen east and southeast of the north cone of Mount Young in satellite imagery the following week. A small pit formed in the cone’s crater by September 27, and between September 29 and October 1, a new tephra cone grew around the pit and thick tephra deposits accumulated on the adjacent crater floor. \r\n\"Weak tremor was reported on October 2–4, 8, and 10, and a small SO2 plume was detected in OMPS satellite data on October 6, but no infrasound was detected in early October. AVO saw no evidence of eruptive activity in satellite images during this period and the crater lake returned by October 11. This lull in activity led AVO to lower the Aviation Color Code and Volcano Alert Level to YELLOW and ADVISORY on October 12. \r\n\"Strong seismic tremor began again on October 26 at 04:47 UTC (October 25 at 19:47 HADT), accompanied by a small ash plume reaching an altitude of 12,000 ft (3,700 m) ASL and infrasonic tremor detections at the array on Adak Island. This activity triggered an increase in the Aviation Color Code and Volcano Alert Level again to ORANGE and WATCH. Small explosions, accompanied by ground-coupled airwaves and some infrasound detections, continued until November 1. Clouds obscured all satellite views during this time, but a possible SO2 signal was detected in OMPS satellite data on October 30. \r\n\"Unfortunately, the satellite connection to the real-time seismic data receive facility (on Amchitka Island) failed on November 1 and was not recovered until June 2019. During the outage, AVO observed no changes in satellite imagery and detected no explosions from the nearby Adak Island infrasound array. Owing to a lack of evidence of ongoing eruptive activity, AVO lowered the Aviation Color Code and Volcano Alert Level to YELLOW and ADVISORY on November 21. With continued apparent quiescence, AVO changed the Aviation Color Code and Volcano Alert Level to UNASSIGNED on December 19. After the missing seismic data were recovered in 2019, a retrospective analysis found that strong tremor and likely eruptive activity continued through at least November 11, 2018. Satellite imagery showed steam in the crater on December 1, 10, and 19, 2018. \r\n\"Although the unrest in 2014-2015 was associated with considerable deformation, InSAR measurements have shown little to no deformation since then, and even the 2018 activity lacked associated surface displacement. In a preliminary analysis of Sentinel-1 interferograms, a small signal occasionally appeared on the west flank of Mount Young’s north cone, but this signal could simply reflect surface deformation, atmospheric noise, or a change in spectral properties due to freshly deposited ash. A more spatially extensive signal might exist in the center of the caldera near the modeled deformation source of the 2014-2015 inflationary episodes (DeGrandpre and others, 2019). This signal could represent deformation from a deeper source, but the magnitude of surface displacement is so small (less than 1 millimeter [0.04 inches]) that the mechanisms producing the signal would be more likely related to processes like gas exsolution or crystallization rather than magma volume flux. Additional analysis is required to eliminate atmospheric noise as a possible source of the apparent displacement.\"","StartYear":2018,"StartMonth":9,"StartDay":16,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mount Young","ParentVolcano":"Semisopochnoi","VolcanoID":"ak44","ParentVolcanoID":"ak248"},{"ID":4853,"Name":"Shrub 2019/03","Description":"From Orr and others, 2023: \"During a field visit to the Klawasi group mud volcanoes in June 2019, AVO scientists found a new extrusion of mud at the base of Shrub mud volcano’s north flank. The extrusion was active during the visit and had started recently, given that evergreens partly buried by the flow were just beginning to turn orange. Satellite imagery indicates this activity probably started between March 7 and March 9. The flows, which came from vents on mud deposits dating to the late 1990s and early 2000s, extended northeast and spread into the adjacent forest to the north. Satellite data showed that the extrusive activity continued until at least October 21 before stopping sometime in the subsequent winter. The vents were inactive by the time satellite views of the area resumed in early February 2020, although new vents had opened immediately south of the old ones.\"","StartYear":2019,"StartMonth":3,"StartDay":8,"StartTime":null,"StartQualifier":1,"StartQualifierUnit":"Days","EndYear":2019,"EndMonth":12,"EndDay":19,"EndTime":null,"EndQualifier":58,"EndQualifierUnit":"Days","Volcano":"Shrub","ParentVolcano":"Klawasi Group","VolcanoID":"ak253","ParentVolcanoID":"ak163"},{"ID":4859,"Name":"Isanotski non-eruptive activity 2019","Description":"From Orr and others, 2023: \"A series of small earthquakes thought to be associated with glacial activity took place near the summit of Isanotski Volcano in the spring of 2019. Around 13,000 earthquakes were detected from March 12 to May 11, forming several swarms that each lasted hours to days. Tremor bursts were also recorded within a few days after some of the swarms. Sporadic seismicity continued into the summer, although this seismicity was less significant than that of the spring. Most earthquakes recorded near Isanotski Volcano in 2019 were too small to be located, so their local magnitudes could not be determined. However, a larger event on May 1 was located close to the surface near the summit of Isanotski Volcano and had an ML of −0.3. These traits are consistent with a glacial seismicity source. Photographs taken in August 2019 show crevasses in the ice on the north side of Isanotski Volcano that may be related to the spring seismicity. \r\n\"The 2019 seismic sequence began on March 12 at 05:20 UTC (March 11 at 21:20 AKDT). For the first four days, the earthquakes in the sequence had low amplitudes, but on March 16, events suddenly increased in amplitude and decreased in rate. These events continued until late on March 21. After a 3-hour pause, in the early morning of March 22, a 4-minute-long tremor burst followed the earthquakes. A second swarm began several hours later and ended on March 25. The seismicity resumed on March 31 with a third earthquake swarm that continued for about a day and a half. This was followed by a series of short tremor bursts and LP earthquakes on April 4. \r\n\"Another series of earthquake swarms, each lasting less than a day, took place on April 12-16. These were followed by a 1.5-minute-long tremor burst on April 18. The last large swarm of the sequence started on April 21 and continued until May 9. Like the opening swarm in March, the earthquakes of this final swarm sharply increased in amplitude after about 5 days. The swarm was also followed by a 6-minute-long tremor burst on May 12. Although the tremor burst concluded the main sequence, tremor was also noted on May 30 and June 1. Occasional earthquakes occurred during the pauses between the March-May swarms, and more occurred afterward until at least July. These sporadic events are difficult to describe thoroughly because they typically had very low amplitudes (which could easily be masked by noise) and because local monitoring is limited.\"","StartYear":2019,"StartMonth":3,"StartDay":12,"StartTime":"05:20:00","StartQualifier":null,"StartQualifierUnit":null,"EndYear":2019,"EndMonth":7,"EndDay":null,"EndTime":null,"EndQualifier":1,"EndQualifierUnit":"Months","Volcano":"Isanotski","ParentVolcano":"Isanotski","VolcanoID":"ak135","ParentVolcanoID":"ak135"},{"ID":4857,"Name":"Martin non-eruptive activity 2019","Description":"From Orr and others, 2023: \"Although no historical eruptions of Mount Martin are known, its fumarolic field frequently produces towering vapor plumes that can reach as high as 1,000 m above the summit when environmental conditions are right. Such a plume was observed on March 14, as described in two PIREPs released by the Federal Aviation Administration (FAA). The reports, which described steaming to 10,000 ft (3,000 m) from 'a mountain,' were linked to Mount Martin and quickly verified as typical activity for this volcano. \r\n\"Mount Martin showed an increase in seismicity during 2019, although the cause was undetermined. Earthquakes at the volcano are common - AVO typically locates as many as one dozen weekly - but approximately 400 located earthquakes took place in September 2019, a swarm that was the largest at Mount Martin since 2006 (O’Brien and others, 2012). The activity declined to about 100 earthquakes per month in October and November, then returned to background levels in December. Background-level earthquakes at Mount Martin typically cluster at a shallow depth in a diffuse pattern north of the summit. In contrast, the 2019 swarm was located predominantly in the west half of this background cluster zone and at a slightly greater depth. AVO closely monitored Mount Martin’s temporary increase in seismicity but kept the Aviation Color Code and Volcano Alert Level at GREEN and NORMAL throughout the year.\"","StartYear":2019,"StartMonth":3,"StartDay":14,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2019,"EndMonth":12,"EndDay":15,"EndTime":null,"EndQualifier":15,"EndQualifierUnit":"Days","Volcano":"Martin","ParentVolcano":"Martin","VolcanoID":"ak189","ParentVolcanoID":"ak189"},{"ID":4856,"Name":"Iliamna avalanches 2019","Description":"From Orr and others, 2023: \"Although Iliamna Volcano maintained an Aviation Color Code and Volcano Alert Level of GREEN and NORMAL throughout 2019, AVO observed seismicity episodes suggestive of ice and rock avalanches, and two large avalanches were confirmed in satellite images. Avalanches like these are common on Iliamna Volcano, where they are composed mostly of ice and snow (as much as 80 percent by volume) (Schneider and others, 2010), and they are highly mobile, traveling at mean speeds of approximately 50 meters per second (m/s) [110 miles per hour] and reaching peak speeds, estimated via numerical modeling, of more than 70 m/s [160 miles per hour] (Caplan-Auerbach and Huggel, 2007; Schneider and others, 2010). \r\nThe first of the two large ice and rock avalanches took place on the south flank of the volcano in late March. This first avalanche started at an elevation of 2,800 m [9,200 ft] and ran for about 3 km [1.9 mi], reaching a final elevation of 1,450 m [4,760 ft]. A seismic signal inferred to be from the avalanche was detected on stations as far as approximately (~) 100 km [60 mi] away at 18:00 UTC (10:00 AKDT) on March 26, with a recorded duration of 3-4 minutes. This timing for the ice and rock avalanche was roughly confirmed by Landsat satellite images taken before and after the seismic signal, although the signal of the avalanche did not appear in infrasound data. \r\n\"The second, much larger ice and rock avalanche took place on the east flank of Iliamna Volcano at 00:03 UTC on June 21 (June 20 at 16:03 AKDT) (Toney and others, 2021). An oblique aerial photograph taken the same day and Copyright 2019 DigitalGlobe, Google Earth Copyright 2019 DigitalGlobe, Google Earth satellite imagery acquired the next day showed the flow deposit on Iliamna Volcano’s east-facing Red Glacier. Red Glacier has hosted many debris avalanches in prehistoric and historical time (Waythomas and others, 2000); its most recent avalanche of comparable size took place in May 2016. The June 21 rock and ice avalanche initiated less than 1 km [0.6 mi] from the volcano’s summit and traveled east for about 8 km [5 mi]. Measurements taken from satellite imagery estimate that the deposit covered an area spanning approximately 7.1×10^6 m^2 [76,000,000 ft^2]. Assuming an average deposit thickness of 0.5 m, this yields a volume of about 3.6×10^6 m^3 [39,000,000 ft^2]. \r\n\"The second ice and rock avalanche on Iliamna Volcano, like the July 15 ice and rock avalanche on Mount Spurr, generated energetic seismic and acoustic signals that were recorded both locally and regionally (Toney and others, 2021). One local seismic station recorded at least 100 minutes of precursory seismicity (J. Caplan-Auerbach, Western Washington University, written commun., 2019). High-frequency signals associated with the event itself were recorded on local and regional (greater than 100 km [60 mi] away) seismic networks, and LP seismic signals were recorded more than 600 km [370 mi] away. Pre-avalanche seismicity was also documented during Red Glacier avalanches in 1994, 1997, 2003, and 2016 (Caplan-Auerbach and Huggel, 2007; J. Caplan-Auerbach, Western Washington University, written commun., 2016). The infrasound array in Dillingham detected acoustic waves from the event, as did the infrasound arrays in the Alaskan cities of Sand Point and Fairbanks.\"","StartYear":2019,"StartMonth":3,"StartDay":26,"StartTime":"18:00:00","StartQualifier":null,"StartQualifierUnit":null,"EndYear":2019,"EndMonth":6,"EndDay":21,"EndTime":"00:03:00","EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":4511,"Name":"Pavlof 2019 activity","Description":"From Orr and others, 2023: \"In 2019, Pavlof Volcano showed signs of weak activity that caused AVO to raise the Aviation Color Code and Volcano Alert Level to YELLOW and ADVISORY three times...The first change was made on May 15, 2019, in response to an increase in seismic tremor and webcam images of robust summit degassing. The Aviation Color Code and Volcano Alert Level were lowered back to GREEN and NORMAL on June 12, after activity declined...\r\n\"A total of 90 earthquakes were located within 20 km of Pavlof Volcano during 2019. Of these events, 44 were classified as volcano-tectonic (VT) earthquakes, with a collective depth range of −2.85 to 31.5 km and a local magnitude (ML) range of −0.41 to 1.65. The other 46 were classified as LP earthquakes, with a depth range of 8 to 34 km and a ML range of −0.36 to 1.65. Of the 46 LP events, 21 were located ~5 km northeast of Pavlof Volcano beneath Pavlof Sister, a pattern also seen in the seismicity of previous years (Power and others, 2004b). AVO recorded several tremor episodes at Pavlof Volcano in 2019. There is no obvious temporal relationship between the tremor and the earthquake activity...The activity in 2019 started with weak, intermittent tremor on May 15-19. Two brief tremor signals (~3 minutes each) were then observed on May 29, followed by several brief tremor bursts on May 31...\r\n\"The annual number of earthquakes located at Pavlof Volcano increased between 2017 and 2019. This trend is probably influenced by improvements made to Pavlof Volcano’s seismic network in the summer of 2017, but the fact that AVO located significantly fewer events in 2019 than 2018 suggests a change in activity level unrelated to the network improvements.\"","StartYear":2019,"StartMonth":5,"StartDay":15,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2019,"EndMonth":6,"EndDay":12,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":4860,"Name":"Makushin non-eruptive activity 2019","Description":"From Orr and others, 2023: \"Earthquake swarms are common at Makushin Volcano and several took place in 2019. Most swarms consisted of fewer than 10 events each; however, two more prominent swarms (on May 15 and June 18) contained more than 40 events each. Earthquakes in both swarms were located at depths of 5-10 km. The May 15 swarm comprised 45 earthquakes, located 17 km [10.6 mi] east of the volcano’s summit, and the June 18 swarm comprised 66 earthquakes, located 1-3 km southeast of the summit. A third, smaller swarm of 19 earthquakes took place on June 22, at similar depths to the earlier swarms and 11-12 km east-southeast of the summit. The Aviation Color Code and Volcanic Alert Level of Makushin Volcano remained at GREEN and NORMAL throughout the year.\"","StartYear":2019,"StartMonth":5,"StartDay":15,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2019,"EndMonth":6,"EndDay":22,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":4521,"Name":"Great Sitkin 2019 activity","Description":"From Orr and others, 2023: \"AVO identified a single small explosion associated with Great Sitkin Volcano’s seismic unrest [in 2019]. It took place at 05:40 UTC on June 2 (June 1 at 20:40 HADT) and produced an emergent waveform with most of its energy between 1 and 5 hertz, similar to other small explosions recorded at Great Sitkin Volcano since January 2017. The event had a duration of 2 minutes and 17 seconds, determined using the methodology described in Searcy and Power (2020) for calculating the duration of explosions. No associated infrasound signal was observed on the instruments AVO operates in the City of Adak, indicating that the explosion was small...\r\n\"The Aviation Color Code and Volcano Alert Level were elevated...to YELLOW and ADVISORY on June 2, after the identification of the explosion signal recorded June 1. The Aviation Color Code and Volcano Alert Level were lowered again to GREEN and NORMAL on July 15, on the basis of declining seismicity. The Aviation Color Code and Volcano Alert Level remained there through the end of the year...\r\n\"During 2019, AVO located 629 earthquakes at Great Sitkin Volcano, principally clustered within the shallow crust extending from the summit to roughly 10 km [6 mi] deep. Additional shocks were also located between 10 and 35 km [6-22 mi] deep, with waveforms and frequency contents indicating both VT and deep LP events. Local magnitudes of located events ranged from −1.37 to 2.22. The largest event was located roughly 20 km [12 mi] southwest of the summit of Great Sitkin Volcano at a depth of 8.6 km [5.3 mi]. This hypocenter was deeper than those for earthquakes typically associated with volcanic processes beneath the volcano. \r\n\"The Great Sitkin Volcano seismic network experienced several station failures in 2019, impairing AVO’s ability to locate earthquakes. The most notable failure period spanned January to mid-June. These failures are likely the cause of a reduction in the number of located earthquakes in early 2019 relative to 2018, and the cause of an absence of shallow hypocenters detected in the first half of 2019. In response to the failures, AVO carried out a major upgrade to the seismic network in June 2019. The upgrades involved changing most of the older analog stations (installed in 1999) to broadband digital stations, although the analog stations GSSP and GSCK were left in operation for continuity. These network upgrades resulted in significantly improved station performance for the remainder of 2019.\"","StartYear":2019,"StartMonth":6,"StartDay":1,"StartTime":"21:40:00","StartQualifier":null,"StartQualifierUnit":null,"EndYear":2019,"EndMonth":7,"EndDay":15,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":4541,"Name":"Shishaldin 2019","Description":"From Orr and others, 2023: \"Shishaldin Volcano erupted from July 2019 through the end of the year, with Strombolian explosions, lava flows and lahars on the volcano’s flanks, and sporadic ash clouds. The eruption was the most significant at Shishaldin Volcano since 1999, when an eruption produced Strombolian explosions, lahars, and a subplinian ash cloud that reached 45,000 ft (13,700 m) ASL (Nye and others, 2002; Stelling and others, 2002; McGimsey and others, 2004). Prior to 2019, the most recent eruption to send lava flows down the volcano’s flanks took place in 1955 (Anchorage Daily News, 1955). A questionable news report from 1976 (Andersen, 1976) described lava flows at Shishaldin Volcano that should probably be attributed instead to Pavlof Volcano, which was erupting at that time. Although Shishaldin Volcano erupted from September through October 1975, no lava flows were reported. Thus, the 2019 flows were likely the first on the flanks of Shishaldin Volcano in 64 years and represent a departure from the typical style of its historically observed eruptions. Eruptions at Shishaldin Volcano more commonly consist of Strombolian explosions and lava fountaining within the summit crater. \r\n\"The initial 2019 eruptive activity of Shishaldin Volcano began in July, continued into September, and featured the growth of a small spatter cone in the summit crater. The lava column then withdrew in mid-September, causing the crater floor to collapse and pausing the eruption for approximately one month. Activity resumed in mid-October with a new, rapidly growing spatter cone within the summit crater, while small lava flows spilled out of the crater and ran ~2 km [1.2 mi] down the volcano’s north flank. These flows melted into the snow and ice, producing small lahars that followed drainages north to the Bering Sea. Several collapse events from the summit spatter cone in November and December left lobate flowage deposits on Shishaldin Volcano’s north flank and produced small ash plumes that drifted downwind. Finally, a collapse event on December 12 produced a larger ash plume, which reached an altitude as high as 23,000 ft (7,000 m) ASL, generated three detected lightning strokes, and deposited ash on the southeast flank of the volcano. \r\n\"The following paragraphs describe each phase of the 2019 eruption in greater detail…\r\n\"Eruption Buildup (July 1-July 23) \r\n\"Satellite imagery indicated elevated surface temperatures at Shishaldin Volcano starting July 1, and the brightness temperatures continued increasing for the next two weeks. Tremor and LP earthquakes were also detected during the same period and may have started occurring as early as mid-June. On July 10, field crews noted that the summit plume was unusually vigorous, although no sulfur dioxide (SO2) was detected in satellite data that day. \r\n\"On July 12, an overflight by a crew associated with the Plate Boundary Observatory recorded visible incandescence within the summit crater (K. Austin, University NAVSTAR Consortium [UNAVCO], written commun., 2019). This report, along with increasing surface temperatures detected in satellite data and increased seismic activity, prompted AVO to raise the Aviation Color Code and Volcano Alert Level to YELLOW and ADVISORY on July 13. Elevated surface temperatures and an increasing amplitude of seismic tremor continued from July 12 to 23. \r\n\"Cone Eruption (July 24-September 19) \r\n\"On July 23, AVO field crews photographed several new volcanic features at the summit of Shishaldin Volcano: a small cone within the summit crater, active lava flowing around the base of this cone, and minor tephra deposits on the inside walls of the crater. The confirmation of active lava at the surface triggered AVO to raise the Aviation Color Code and Volcano Alert Level to ORANGE and WATCH on July 24. Clear, high-resolution satellite images documented the spatter cone as it continued to grow and showed signs of activity through mid-September. These images also showed occasional light ash deposits on the upper flanks of the volcano, but no lava or significant amounts of ash appeared outside the summit crater. \r\n\"Bursts of seismic tremor, thought to be caused by Strombolian explosions, were first detected on July 25 and occurred intermittently through August. This eruptive style was confirmed on August 16 by a passing observation plane operated by the National Oceanic and Atmospheric Administration Alaska Fisheries Science Center, which recorded visible and infrared video of the volcano. Seismic tremor, recorded as real-time seismic amplitude measurements (RSAM), also steadily increased through August, peaked around September 6, and then decreased markedly after September 14. Minor SO2 emissions were detected on August 27-28 and September 2 in sensitive ultraviolet (UV) satellite images (from the TROPOspheric Monitoring Instrument [TROPOMI] on the Copernicus Sentinel-5 Precursor satellite), but not by less-sensitive infrared (IR) satellite sensors (Infrared Atmospheric Sounding Interferometer [IASI] instruments onboard the Meteorological Operational satellite series). The last visual confirmation of eruptive activity at the summit during this period was a Landsat 8 satellite image taken on September 9. \r\n\"Clear, high-resolution satellite images showed that the spatter cone continued growing with signs of activity through mid-September, although it remained confined within the summit crater. Besides the occasional dusting of light ash on the upper flanks of the volcano, no lava or significant amounts of ash were deposited outside the crater. \r\n\"Pause (September 19-October 13) \r\n\"On September 19, the spatter cone, which had grown since July, collapsed into the crater. The event was recognized during a retrospective analysis of borehole tiltmeter data from stations installed on the flanks of Shishaldin Volcano by the UNAVCO Plate Boundary Observatory. This collapse was the largest-amplitude tilt signal recorded during the eruption and is interpreted to reflect the drainage of magma from the conduit. \r\nAlthough cloudy conditions blocked satellite views at the time of the collapse event, clear satellite images taken on September 23 showed reduced mid-IR signatures, indicating lower surface temperatures and a lack of significant eruptive activity. More satellite images taken on September 26 confirmed the crater floor had collapsed and that no evidence of ongoing eruptive activity remained. As a result, on September 26, AVO downgraded the Aviation Color Code and Volcano Alert Level to YELLOW and ADIVSORY. The lack of eruptive activity and the collapse of the cone were again confirmed in a clear, high-resolution satellite image taken on October 3. \r\n\"Renewed Eruption; North Flank Lava Flows and Lahars; Cone Collapses (October 13-End of Year) \r\n\"On October 13, satellite imagery showed an increase in surface temperatures at Shishaldin Volcano, signaling renewed eruptive activity. More satellite observations from October 17 confirmed the growth of a new spatter cone within the summit crater. In response, AVO changed the Aviation Color Code and Volcano Alert Level to ORANGE and WATCH later that day. Activity at the volcano escalated rapidly, as indicated by the detection of Strombolian explosions in infrasound data, observations of incandescence in webcam images, the detection of SO2 emissions in satellite data, and an increase in seismic tremor. Infrasound signals were first recorded on October 18 and took place at 15-30-second intervals by October 21. The first observation of incandescence at Shishaldin Volcano during this period was made from a webcam on the southwest flank of Isanotski Volcano during the night of October 19-20. On October 21, satellite TROPOMI sensors detected SO2 emissions, and AVO recorded a spike of seismic tremor at the volcano. This first tremor spike, as well as subsequent ones, was characterized by RSAM values that increased slowly over several days and sharply decreased over several hours, resulting in a 'shark fin' pattern.\r\n\"On October 24, during another seismic tremor peak, a clear satellite image captured an active, 800-meter-long lava flow traveling down the northwest flank of Shishaldin Volcano. The flow melted snow and ice, generating a lahar that had traveled ~3 km [~2 mi] down drainages to the north. In addition, minor ash deposits were seen on snow 8 km [5 mi] southeast of the summit in the image. The same day, an anonymous pilot of a passing airplane reported to AVO the presence of clouds over the volcano that looked like 'smoke rings.' The regional infrasound array at Sand Point, Alaska, detected clear explosions associated with this activity. \r\n\"Cyclic increases in seismic tremor, presumably from Strombolian-type explosions, were accompanied by ash and gas emissions and continued to take place through the end of 2019. Observers on a passing U.S. Fish and Wildlife Service flight and AVO field crews on Unimak Island confirmed this Strombolian-type explosive behavior on November 11 and December 20, respectively. At times of increasing tremor amplitude and when viewing conditions permitted, active lava flows on the north flank of the volcano were seen in satellite and webcam views and by observers in the City of Cold Bay. Infrared satellite sensors also detected an increase in radiative power at the volcano, reflecting the increased effusive activity. \r\n\"In partnership with UNAVCO, AVO scientists experimented with recording high-rate tilt data (1 sample per second) using the tiltmeter at station AV36, located on the western margin of Shishaldin Volcano. The instrument detected several episodes of explosive activity at the summit while recording at this sampling rate; during each episode, the data showed an hours-long increase in amplitude culminating in several hours of high-amplitude activity bursts. Ground motions during these events were generally tangential to the edifice. These data show that open-system volcanoes like Shishaldin Volcano generate appreciable ground deformation over timescales and at amplitudes that can be recorded by borehole tiltmeters.\r\n\"During the summer and early fall of 2019, only UV satellite instruments, such as TROPOMI, detected SO2 at Shishaldin Volcano as a result of their higher sensitivity than IR sensors. Detections from these instruments stopped in November, however, as the available UV light decreased. In contrast, IR SO2 sensors, such as IASI sensors, although less sensitive, do not lose effectiveness in the winter. IASI sensors began detecting SO2 from Shishaldin Volcano on October 28, and these detections continued in November and December. Considering the lower sensitivity of satellite IR to SO2, the IASI detections indicate that gas emissions were higher at the end of the year than earlier in the eruption. \r\n\"After each tremor and emission spike, activity quickly decreased and clear satellite images showed a pause in lava effusion. Synthetic Aperture Radar (SAR) images from the TerraSAR-X and TanDEM-X satellites, provided during the eruption by S. Plank (German Aerospace Center), indicated that the summit spatter cone experienced partial collapses during many of these episodes. Collapse events were specifically noted on November 11, November 23, December 5, and December 12. Lobate flowage deposits appeared downslope from the cone after each event. \r\n\"The largest of these collapse events, which took place on December 12 at 16:10 UTC, was detected in seismic and infrasound data, webcam photos, and satellite imagery. Photographs of the volcano after the event showed an ash cloud reaching an altitude of about 25,000 ft (7,600 m) ASL. Three lightning strokes were also detected from this cloud. Unlike other collapse events, the December 12 event was followed by elevated tremor and continued lava effusion, the latter of which was visible in satellite images and in photographs taken from the City of Cold Bay. This event was associated with the largest ashfall of 2019, although only a minor amount of ash was deposited on the southeast flank of Shishaldin Volcano. \r\n\"A field crew visited Shishaldin Volcano on December 20, 2019, and although the lava flows were inactive during the visit, the vent itself was producing regular Strombolian explosions. The crews sampled the December 12 ash deposit, later analysis of which determined the tephra to be a mix of lithic, tachylite, and sideromelane grains. The sideromelane grains were basaltic, with glass composed of ~52 weight percent SiO2 and minerology consisting of plagioclase, olivine, and magnetite, although only plagioclase and olivine existed as larger (greater than 0.1 millimeter [0.004 inch]) phenocryst phases. The high proportion of tachylite and lithic grains in the tephra supports a cone-collapse origin for the deposit - the composition indicates a high proportion of the material was mobilized from previously deposited and cooled grains. \r\n\"The next active lava effusion periods were noted on December 21 and December 26 (after the December field visit). Cloudy conditions generally obscured activity at Shishaldin Volcano during the last few days of the year, but eruptive activity continued into January 2020. \r\n\"Although the 2019 eruption deposited only minor amounts of ash on the flanks of Shishaldin Volcano, the lava flows from the event extended 1-2 km [0.6-1.2 mi] down its north flank. Associated lahar deposits traveled even farther, reaching as far north as the Bering Sea. The lava flows of 2019 were the first historically well-documented ones at Shishaldin Volcano and likely represented the first lava flow activity outside its summit crater in more than 60 years.\"\r\nFrom Orr and others, 2024: \"Shishaldin Volcano erupted from July 2019 to March 2020. The 2019 activity was documented in Orr and others (2023) and the 2020 activity is documented herein…\r\n\"Ash-Rich Paroxysm Sequence (January 1–20) \r\n\"Eruptive activity at the start of 2020 followed a similar pattern to that established in November 2019: seismic tremor and lava flow activity generally increased over a period of several hours before abruptly shutting down in days-long pauses. Unlike activity in the prior weeks, however, three periods of escalating activity in January culminated in increased ash emissions, prompting AVO to issue a Volcanic Activity Notice (VAN) each time.\r\n\"Shishaldin Volcano began 2020 with an Aviation Color Code and Volcano Alert Level of ORANGE and WATCH. Elevated surface temperatures visible in satellite data on January 2 suggested that weak eruptive activity, confined to the vent, was occurring. Seismicity began to increase on January 3, indicating increasing eruptive activity. This was confirmed by a passing pilot, who reported a clear view of lava fountaining and a robust, steam-rich plume that probably contained some ash from the fountaining. At the same time (starting around 19:00 UTC [10:00 AKST]), satellite views and additional PIREPs recorded ash-poor plumes from the volcano that may have reached as high as ~24,000 ft (~7,300 m) ASL. The fountaining at Shishaldin Volcano was associated with increasing seismic tremor and the emplacement of lava flows mostly concentrated on the volcano’s northwest flank. AVO issued a VAN at 20:38 UTC (11:38 AKST) but did not change the Aviation Color Code or Volcano Alert Level. \r\n\"Seismic tremor decreased sharply at 20:48 UTC (11:48 AKST), and at about the same time, a PIREP indicated that the plume height had risen to ~27,000 ft (~8,200 m) ASL. Volcanic lightning was detected at 21:07 UTC (12:09 AKST), suggesting that the concentration of ash in the plume had increased. These ash emissions did not last long; the concentration was decreasing by 21:30 UTC (12:30 AKST). A WorldView-2 satellite image acquired at 22:22 UTC (13:22 AKST) revealed the state of the volcano: the lava flows active earlier in the day had stalled and were cooling, new lobate pyroclastic flow deposits had been emplaced on the west and south flanks, and an ash-rich plume was drifting southeastward. The new pyroclastic flow deposits were the first to affect the south flank of the volcano during this eruption; prior deposits were restricted to the north flank. Deposition on the west and south flanks of the volcano required overtopping the topographic high point of the summit crater, suggesting they were deposits from the collapse of an ash column as opposed to debris from a tephra cone collapse. Eruptive activity associated with the January 3 event was not observed directly afterward. Lava flow activity at Shishaldin Volcano increased again after January 3, and by January 6, incandescent flows were visible from the City of Cold Bay. The frequent detection of infrasound signals suggested the occurrence of Strombolian explosive activity. Seismic tremor, already elevated, began increasing further on the morning of January 7, and starting around 16:00 UTC (7:00 AKST) that morning, a plume reaching an altitude of ~20,000 ft (~6,100 m) ASL was detected in satellite data. Strong mid-infrared satellite signatures accompanied the plume, suggesting ongoing lava effusion and vigorous lava fountaining, similar to the behavior seen on January 3. A VAN noting this increased activity was issued at 18:39 UTC (9:39 AKST), although the Aviation Color Code and Volcano Alert Level were not changed. At ~20:00 UTC (~11:00 AKST), the seismic tremor started to decline, followed by the detection of volcanic lighting at 20:25 UTC (11:25 AKST). Satellite images acquired shortly afterward indicated that the plume had become more ash-rich and now reached an altitude as high as ~27,000 ft (~8,200 m) ASL, although tremor remained low. These observations prompted AVO to increase the Aviation Color Code and Volcano Alert Level to RED and WARNING at 21:33 UTC (12:33 AKST). Light ashfall from this event was reported in the City of Cold Bay.\r\n\"The plume appeared to have detached from the vent by 22:00 UTC (13:00 AKST), indicating that ash emission had slowed or stopped. The Aviation Color Code and Volcano Alert Level were subsequently lowered to ORANGE and WATCH on January 8 at 04:17 UTC (January 7 at 19:17 AKST). Synthetic aperture radar images acquired later that day showed that the crater had deepened, and the cone had subsided or collapsed. Like the January 3 event, the January 7 paroxysm was followed by a period of quiescence. The only activity detections at Shishaldin Volcano over the next week were infrasound signals consistent with Strombolian activity on January 10. On January 14, a clear WorldView-2 satellite image showed no volcanic activity within the summit crater or on the flanks.\r\n\"Eruptive activity increased again on January 18; lava flows were visible on the volcano flanks and seismic tremor intensified. At 17:18 UTC (08:18 AKST), a pilot reported visible lava but no ash emissions. Observers in the Cities of Cold Bay and King Cove, Alaska, documented the incandescent lava flow during clear weather that evening. Overnight webcam images from the south flank of Isanotski Volcano also showed lava fountaining, and by January 19 at 9:30 UTC (00:30 AKST), satellite images showed an ash-poor gas plume rising as high as ~18,000 ft (~5,500 m) ASL. The level of activity continued to increase, and as a result, the Aviation Color Code and Volcano Alert Level were increased to RED and WARNING at 17:28 UTC (08:28 AKST). By this point, a continuous, 150-kilometer-long plume was visible in satellite images. PIREPs at 18:15 UTC (09:15 AKST) described ongoing lava flow activity and measured that the plume had reached an altitude of ~25,000 ft (~7,600 m) ASL. Over the following hours, seismic tremor continued to increase and trace ashfall was reported in the City of False Pass, Alaska, 38 km northeast of Shishaldin Volcano. A WorldView-2 image captured activity at the vent during this period. Another PIREP at 21:42 UTC (12:42 AKST) indicated that the plume had climbed to ~30,000 ft (~9,100 m) ASL.\r\n\"The seismic tremor dropped precipitously just after 00:00 UTC on January 20 (January 19 at 15:00 AKST). Satellite data acquired about an hour later showed that the plume had transitioned to a more ash-rich composition, a change confirmed by PIREPs. Ash emissions continued for the next several hours. Then, shortly before 05:00 UTC (20:00 AKST), ash emissions stopped and the plume detached from the vent. With the cessation of eruptive activity at the vent, AVO lowered the Aviation Color Code and Volcano Alert Level to ORANGE and WATCH at 09:37 UTC (00:37 AKST).\r\n\"Prolonged Eruption Hiatus (January 20–March 11)\r\n\"Satellite data after the January 20 paroxysm showed new ash deposition—the ash-poor lava fountaining phase produced trace deposits extending northeastward toward False Pass, whereas the later ash-rich phase produced more substantial deposits extending southeastward. Satellite radar imagery also showed that the volcano crater was larger and deeper after the event. The last detected infrasound and seismic event of note during this period was on January 24, and a WorldView-3 satellite image from January 25 showed no visible eruptive activity. Some discreet seismic events and infrasound signals were detected occasionally later on, but these did not build to a clear eruptive signal like that which followed the eruption events earlier in January. On February 7 at 01:20 UTC (February 6 at 16:20 AKST), the Aviation Color Code and Volcano Alert Level were lowered to YELLOW and ADVISORY. No other significant activity was detected at the volcano in February, and clear satellite images showed quiet conditions consisting of minor steaming at the vent and cooling lava flow deposits on the flanks.\r\n\"Final Renewed Eruption (March 11–31)\r\n\"After weeks of quiescence, eruptive activity resumed in March 2020, although it was contained within the summit crater. The first indication of renewed activity appeared in a WorldView-2 satellite image from March 11 that showed a small area of recent ash deposits near the summit crater. The inside of the crater was mostly obscured by steam in the image, but it was generally similar to its appearance in other high-resolution satellite images from February. In the following days, mid-infrared satellite images began to show increased surface temperatures at the volcano. A WorldView-3 image from March 14 showed a saturated short-wave infrared signature at the summit, indicating that lava was erupting again within the summit crater. In response, AVO increased the Aviation Color Code and Volcano Alert Level to ORANGE and WATCH on March 15 at 6:31 UTC (22:31 AKDT on March 14).\r\n\"During the following few weeks, seismicity was elevated and small explosions (probably from Strombolian activity) were detected occasionally in infrasound data. Satellite radar images suggested renewed cone growth, although all eruptive activity was confined within the summit crater. Another WorldView-3 image from March 22 showed activity similar to that on March 14. \r\n\"Seismicity declined thereafter through the end of the month, and an April 1 satellite image showed only a steam plume and no evidence of a heat source, suggesting the eruption had ended. On April 2, a clear satellite image with an unobscured view into the summit crater confirmed that no eruptive activity was occurring. Due to an absence of activity, AVO lowered the Aviation Color Code and Volcano Alert Level to YELLOW and ADVISORY on April 16 at 19:44 UTC (11:44 AKDT).\r\n\"Aftermath (April 1–End of Year)\r\n\"Low-level unrest continued at Shishaldin Volcano for months after its 2019–2020 eruption. Elevated surface temperatures continued appearing in satellite images, and frequent satellite detections of SO2 were made in late April and May. These SO2 detections also coincided with the increasing ultraviolet radiation of long summer days, which raises the sensitivity of the TROPOspheric Monitoring Instrument (TROPOMI), a satellite instrument used for these detections. Other remote sensing observations made during this period of low-level unrest indicated that magma was still stored shallowly within the conduit, enabling magma degassing, high temperatures, and minor collapse events within the summit crater.\r\n\"On June 24 at 20:00 UTC (12:00 AKDT), the Aviation Color Code and Volcano Alert Level were lowered to GREEN and NORMAL, reflecting an overall decrease of activity to background levels at the volcano, although AVO continued recording evidence of additional minor collapse events using satellite radar images. Some of these events appeared to produce trace ash deposits on the upper flanks, as seen on April 29 and May 7. AVO workers carrying out annual geophysics station maintenance in August and September did not observe any eruptive activity, but helicopter gas surveys at the same time detected continued SO2 degassing at an emission rate of 100±30 metric tons per day. The surveys also measured high carbon dioxide concentrations relative to measurements from 2015 and 2019, which indicated a new deep magma input into the system.\r\n\"Final Deposits and Samples\r\n\"The 2019–2020 eruption of Shishaldin Volcano resulted in (1) many lava flows on the north flank of the volcano, (2) pyroclastic flow deposits related to cone collapse events in December and three eruption paroxysms in January, and (3) lahars that inundated drainages north of the volcano and reached the Bering Sea coast. Accurate mapping of the lava flows was difficult because of poor orthorectification in many of the available high-resolution satellite images, in turn caused by the typically oblique image viewing angles and the steep flanks of Shishaldin Volcano. \r\n\"Satellite images taken on January 14 and January 25 provided close-to-nadir images (11º and 17º off nadir, respectively) that allowed the final deposits to be mapped with reasonable accuracy. The lava flows covered less than 0.9 square kilometers (km2) and extended as far as 3 km from the vent, primarily occupying three distinct drainages, with each new flow burying the previous one. The pyroclastic flow and lahar deposits were gradational and, in many places, difficult to distinguish from each other in satellite images. Deposits on the volcano’s south flank, especially those from the January 3 paroxysm, were likely all pyroclastic flows generated from ash column collapse that overtopped the high point on the crater rim. The lahars and pyroclastic flows to the north were intermixed, forming lobate deposits on the flatter plains north of the volcano. The deposits suspected to be pyroclastic flows generally extended no more than 3 km from the summit vent, whereas lahars followed drainages and traveled farther, some reaching all the way to the coast (more than 30 km north of the summit). Because of the difficulty in distinguishing between pyroclastic and lahar deposits using satellite images alone, they are mapped as a single unit in figure 14 [in original].\r\n\"Only a few samples are available from the 2019–2020 eruption. Samples of a tephra deposit from a cone collapse event, collected by field crews on December 20, 2019, are described in Orr and others (2023). AVO field crews also sampled the toe of a lava flow on the northeast flank of the volcano in 2022; this sample is currently being studied. Community members in the City of Cold Bay collected ash from the paroxysm of January 7, 2020; others in False Pass collected ash from the early stage of the January 19 paroxysm. Both of these samples were dominated by roughly equal parts (1) juvenile, highly fluidal and glassy sideromelane grains and (2) partially devitrified tachylite grains (classifications by Loewen and others, 2021). However, the samples also contained phenocrysts of plagioclase and olivine, along with microlites of plagioclase, olivine, and magnetite. The glass composition was basaltic and was similar to samples from the 1999 eruption (Stelling and others, 2002).\"","StartYear":2019,"StartMonth":7,"StartDay":12,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2020,"EndMonth":6,"EndDay":24,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":4854,"Name":"Spurr non-eruptive activity 2019","Description":"From Orr and others, 2023: \"On July 15, 2019, at 16:32 UTC (08:32 AKDT), a large ice and rock avalanche took place on the southeast flank of Mount Spurr. A retrospective analysis of satellite imagery indicated the starting zone of the avalanche was less than 1 km from the summit of the volcano. Clear satellite images of the flow deposit showed that it widened before splitting into two lobes that flowed around an elevated lateral moraine dividing the west and east branches of K’idazq’eni Glacier (March and others, 1997; Molnia, 2008). One lobe flowed down the west branch between the moraine and the Crater Peak cone, while the other traveled slightly farther down the east branch of the glacier. Satellite imagery indicated the ice and rock avalanche spanned an area of approximately 2.3×10^6 square meters (m2) [25,000,000 square feet]. Assuming an average deposit thickness of 0.5 m [1.6 feet] yields a volume of about 1.2×10^6 cubic meters (m3) [42,000,000 cubic feet]. \r\n\"The ice and rock avalanche generated energetic seismic and acoustic signals, recorded both locally and regionally. High-frequency signals were detected on the local seismic network and long-period (LP) seismic signals were recorded more than 700 km [435 mi] away. Several local seismic stations also recorded approximately 10 minutes of precursory seismicity. Pre-avalanche seismicity has been previously documented at Iliamna Volcano (Caplan-Auerbach and Huggel, 2007). In addition to the recordings of seismic signals, an infrasound array in Dillingham, Alaska, detected acoustic waves from the event. \r\n\"During an overflight on August 27, AVO staff noted the terrain of the source area consisted of exposed 'slope-parallel lava, with rivulets of meltwater running on its surface.' They found no evidence of increased non-meteorological heating at the summit area (a phenomenon which can trigger ice and rock avalanches) and observed nothing unusual on the other flanks of the summit cone (M. Coombs, USGS, written commun., 2019). The July 15 avalanche took place in an area known for debris flows, as documented by Coombs and others (2006), but previous flows were smaller and more water-rich than the July 15 event. Mount Spurr remained at an Aviation Color Code and Volcano Alert Level of GREEN and NORMAL throughout 2019.\"","StartYear":2019,"StartMonth":7,"StartDay":15,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2019,"EndMonth":7,"EndDay":15,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Spurr","ParentVolcano":"Spurr","VolcanoID":"ak260","ParentVolcanoID":"ak260"},{"ID":4641,"Name":"Semisopochnoi 2019/7","Description":"From Orr and others, 2023: \"Activity at the north cone of Mount Young, which began in September 2018, continued in 2019 with sporadic eruptive activity. Seismic tremor and explosion signals captured most of this activity, along with infrequent infrasound detections and occasional satellite observations of steam and small ash deposits. Although the eruptive style and geophysical characteristics of the 2019 unrest were similar to those of 2018, AVO’s ability to observe them in real time was limited for the first half of the year owing to a prolonged data outage. This outage, caused by a communication failure at the regional data network telemetry hub in Amchitka, lasted from November 2018 to June 2019, at which point communications were restored and the missing data were recovered. \r\n\"Owing to the data outage, the first activity observed at the volcano in 2019 comprised satellite observations of steam in January and a small ash deposit on June 2. Although the north crater of Mount Young has persistently steamed since 2018, the ash deposits observed on June 2 appear to be a more recent change, having followed tremor bursts in mid-May that probably correspond to when they erupted. AVO began receiving seismic data again on June 11 but kept the Aviation Color Code and Volcano Alert Level at UNASSIGNED until early July, when increased tremor prompted a change to YELLOW and ADVISORY. On July 18, the detection of SO2 emissions in TROPOMI satellite data and the recording of ground-coupled airwaves triggered AVO to raise the Aviation Color Code and Volcano Alert Level to ORANGE and WATCH. SO2, steam plumes, ground-coupled airwaves, and infrasound were detected throughout the summer, but no ash deposits were observed. After a period of quiescence, AVO lowered the Aviation Color Code and Volcano Alert Level to YELLOW and ADVISORY on September 18. \r\n\"Beginning on December 7, the detection of many explosions by regional infrasound sensors indicated a renewal of activity at Semisopochnoi Island, triggering AVO to raise the Aviation Color Code and Volcano Alert Level to ORANGE and WATCH. In addition to producing infrasound, the explosions were accompanied by ash emissions visible in satellite imagery, ground-coupled airwaves, and one SO2 detection (on December 12). No ash plumes reaching altitudes greater than 10,000 ft (3,000 m) ASL and no large ash deposits were observed during this eruptive period. The last activity recorded at the volcano in 2019 was an infrasound detection on December 18. On January 9, 2020, AVO lowered the Aviation Color Code and Volcano Alert Level back to YELLOW and ADVISORY.\"\r\nFrom Orr and others, 2024: \"The overall seismicity remained elevated, however, and on February 15, a series of small explosions and tremor bursts were detected. No ash emissions or deposits were identified in satellite imagery, which was frequently cloudy, but the seismic activity led AVO to return the Aviation Color Code and Volcano Alert Level to ORANGE and WATCH. Seismicity did not increase further and clear imagery later confirmed the volcano was not erupting, although steam emissions were visible. On February 26, AVO lowered the Aviation Color Code and Volcano Alert Level to YELLOW and ADVISORY.\r\n\"Activity in mid-March was characterized by nearly continuous tremor and frequent, small explosion signals, but no observations of ash plumes. Regional infrasound arrays detected an explosion at the volcano on March 11, followed by more on March 15-16, all of which were accompanied by ground-coupled airwaves recorded on the local seismic network. During this March explosive period, a dark ash deposit appeared around the north cone of Mount Young and TROPOMI imagery showed a possible SO2 plume. In response to the infrasound and remote sensing observations, AVO raised the Aviation Color Code and Volcano Alert Level to ORANGE and WATCH on March 16. This activity was short-lived; by March 22, a partly cloudy WorldView-1 image showed that a robust steam plume emanated from the north cone of Mount Young and a water lake had appeared deep within its crater. After two weeks with no sign of eruption activity, AVO lowered the Aviation Color Code and Volcano Alert Level to YELLOW and ADVISORY on April 1, 2020.\r\n\"The volcano emitted steam and SO2 regularly throughout the spring and summer, and by June 15, the crater lake had mostly dried up. Planet Labs and Sentinel-2 satellite imagery from June 21 captured an ash deposit extending nearly 4 km [2.5 mi] southward from the north cone crater, accompanied by robust steam emissions and a high-temperature short-wave infrared anomaly within the crater. The appearance of this deposit was associated with ground-coupled airwaves detected on June 16 and 17, but no infrasound. Seismicity at the volcano initially remained elevated, appearing as low-level tremor and small earthquakes, but AVO detected no further explosions in 2020 and its activity waned in the fall. An outage of local real-time monitoring data began on November 11, 2020. Considering the absence of data, the lack of eruptive activity detected since June, and the decaying trend in seismicity, AVO changed the Aviation Color Code and Volcano Alert Level of Semisopochnoi Island to UNASSIGINED on November 20, 2020.\"","StartYear":2019,"StartMonth":7,"StartDay":18,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2020,"EndMonth":6,"EndDay":15,"EndTime":null,"EndQualifier":7,"EndQualifierUnit":"Days","Volcano":"Mount Young","ParentVolcano":"Semisopochnoi","VolcanoID":"ak44","ParentVolcanoID":"ak248"},{"ID":4551,"Name":"Veniaminof 2019 activity","Description":"From Orr and others, 2023: \"On August 1, 2019, AVO received a PIREP of steaming at Mount Veniaminof’s intracaldera cone, which coincided with a weak tremor signal. These observations marked a small but distinct departure from the background level of unrest at the volcano, and as a result, AVO raised the Aviation Color Code and Volcano Alert Level to YELLOW and ADVISORY. Weak seismicity and occasional long-period earthquakes continued intermittently throughout most of August, but by the end of the month, the volcano returned to its background activity level. AVO subsequently lowered the Aviation Color Code and Volcano Alert Level to GREEN and NORMAL on August 25, 2019. No additional unrest took place at Mount Veniaminof for the remainder of 2019.\"","StartYear":2019,"StartMonth":8,"StartDay":1,"StartTime":"14:21:00","StartQualifier":null,"StartQualifierUnit":null,"EndYear":2019,"EndMonth":8,"EndDay":25,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Veniaminof","ParentVolcano":"Veniaminof","VolcanoID":"ak301","ParentVolcanoID":"ak301"},{"ID":4855,"Name":"Redoubt non-eruptive activity 2019","Description":"From Orr and others, 2023: \"Although no eruptive activity was detected at Redoubt Volcano in 2019, on August 16, strong winds entrained and resuspended ash near the volcano. The resuspended ash cloud was not seen in satellite imagery but was visible in webcam views, and PIREPs described it as reaching an altitude as high as 10,000 ft (3,000 m) ASL. The National Weather Service Alaska Aviation Weather Unit issued a significant meteorological weather advisory for aviators, but AVO received no reports of ashfall. The Aviation Color Code and Volcano Alert Level at Redoubt Volcano remained GREEN and NORMAL throughout 2019.\"","StartYear":2019,"StartMonth":8,"StartDay":16,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2019,"EndMonth":8,"EndDay":16,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Redoubt","ParentVolcano":"Redoubt","VolcanoID":"ak231","ParentVolcanoID":"ak231"},{"ID":4561,"Name":"Pavlof 2019","Description":"On October 19, AVO raised the Aviation Color Code and Volcanic Alert Level at Pavlof to YELLOW/ADVISORY. From the Volcano Observatory Notice for Aviation: \"Small explosion signals from Pavlof have been detected on the infrasound network located at Sand Point and on the local seismic network today. The volcano is currently obscured by clouds in satellite images. It is unknown if the explosions produced any volcanic ash, but their small size suggests any hazard is currently confined to the area around the volcano's summit. Because these signals are above normal background for Pavlof, the Alaska Volcano Observatory is raising the Aviation Color Code to YELLOW and the Alert Level to ADVISORY.\" On November 6, 2019, AVO lowered the Aviation Color Code and Volcano Alert Level to GREEN/NORMAL, citing no additional signs of unrest after the explosion signals on October 19.\r\nFrom Orr and others, 2023: \"In 2019, Pavlof Volcano showed signs of weak activity that caused AVO to raise the Aviation Color Code and Volcano Alert Level to YELLOW and ADVISORY three times...They were raised...to YELLOW and ADVISORY on October 19 when small explosion signals were detected by the infrasound array in Sand Point and on the local seismic network, then were lowered back to GREEN and NORMAL on November 6...\r\n\"A total of 90 earthquakes were located within 20 km of Pavlof Volcano during 2019. Of these events, 44 were classified as volcano-tectonic (VT) earthquakes, with a collective depth range of −2.85 to 31.5 km and a local magnitude (ML) range of −0.41 to 1.65. The other 46 were classified as LP earthquakes, with a depth range of 8 to 34 km and a ML range of −0.36 to 1.65. Of the 46 LP events, 21 were located ~5 km northeast of Pavlof Volcano beneath Pavlof Sister, a pattern also seen in the seismicity of previous years (Power and others, 2004b). AVO recorded several tremor episodes at Pavlof Volcano in 2019. There is no obvious temporal relationship between the tremor and the earthquake activity...The activity of 2019 ended with additional tremor pulses that took place on October 18 and December 14.\r\n\"The annual number of earthquakes located at Pavlof Volcano increased between 2017 and 2019. This trend is probably influenced by improvements made to Pavlof Volcano’s seismic network in the summer of 2017, but the fact that AVO located significantly fewer events in 2019 than 2018 suggests a change in activity level unrelated to the network improvements.\"","StartYear":2019,"StartMonth":10,"StartDay":19,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2019,"EndMonth":10,"EndDay":19,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":4571,"Name":"Cleveland 2019/11","Description":"From Orr and others, 2023: \"Thermal anomalies and a small summit steam plume appeared occasionally in satellite imagery over the following several months. Clear satellite views in August 2019 showed that a pit, centered on the January dome, had formed since February. More satellite imagery acquired in early November indicated uplift of the new summit dome. Because this uplift was coincident with an apparent increase in the brightness of the summit thermal anomaly and a more robust steam plume, AVO raised the Aviation Color Code and Volcano Alert Level to ORANGE and WATCH. Subsequent satellite imagery, however, showed that the uplift was an artifact from the satellite viewing angle and was not real. The Aviation Color Code and Volcano Alert Level for Mount Cleveland were returned to YELLOW and ADVISORY on November 15, where they remained for the rest of the year. The repose period of 2019 marked the longest at Mount Cleveland since its onset of eruptive activity in 2001.\"\r\nFrom Orr and others, 2024: \"The character of volcanic activity at Mount Cleveland in late 2019 - low seismicity, occasional thermal anomalies, and a small summit steam plume (Orr and others, 2023) - carried over into 2020, and Mount Cleveland began the year at an Aviation Color Code and Volcano Alert Level of YELLOW and ADVISORY. No changes within the summit crater were observed during the first several months of the year; elevated surface temperatures and a weak steam plume were observed sporadically during periods of clear weather. The low level of thermal activity was corroborated by high-resolution satellite imagery in April and May that showed a partly snowcovered dome, suggesting the surface was cold. \r\n\"Because of the apparent quiescence at Mount Cleveland, its Aviation Color Code and Volcano Alert Level were changed to UNASSIGNED on May 7 at 23:37 UTC (14:37 HADT).\"","StartYear":2019,"StartMonth":11,"StartDay":7,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2019,"EndMonth":11,"EndDay":15,"EndTime":null,"EndQualifier":1,"EndQualifierUnit":"week","Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":4858,"Name":"Pavlof unrest 2019/12","Description":"From Orr and others, 2023: \"In 2019, Pavlof Volcano showed signs of weak activity that caused AVO to raise the Aviation Color Code and Volcano Alert Level to YELLOW and ADVISORY three times...AVO raised the Aviation Color Code and Volcano Alert Level to YELLOW and ADVISORY for the last time on December 28, again on the basis of an increase in seismic tremor levels. Ash emissions from the volcano were not observed during any unrest periods in 2019. \r\n\"A total of 90 earthquakes were located within 20 km of Pavlof Volcano during 2019. Of these events, 44 were classified as volcano-tectonic (VT) earthquakes, with a collective depth range of −2.85 to 31.5 km and a local magnitude (ML) range of −0.41 to 1.65. The other 46 were classified as LP earthquakes, with a depth range of 8 to 34 km and a ML range of −0.36 to 1.65. Of the 46 LP events, 21 were located ~5 km northeast of Pavlof Volcano beneath Pavlof Sister, a pattern also seen in the seismicity of previous years (Power and others, 2004b). AVO recorded several tremor episodes at Pavlof Volcano in 2019. There is no obvious temporal relationship between the tremor and the earthquake activity...The activity of 2019 ended with additional tremor pulses that took place on October 18 and December 14.\r\n\"The annual number of earthquakes located at Pavlof Volcano increased between 2017 and 2019. This trend is probably influenced by improvements made to Pavlof Volcano’s seismic network in the summer of 2017, but the fact that AVO located significantly fewer events in 2019 than 2018 suggests a change in activity level unrelated to the network improvements.\"","StartYear":2019,"StartMonth":12,"StartDay":28,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":4611,"Name":"Great Sitkin activity 2020","Description":"From Orr and others, 2024: \"In late July 2016, Great Sitkin Volcano entered a period of increased unrest characterized by an elevated frequency of earthquakes, anomalous steaming from its summit crater, and small explosive events (Dixon and others, 2020). Similar small earthquakes and steaming from the summit crater continued throughout 2020. \r\n\"AVO located 3,393 earthquakes at Great Sitkin Volcano during 2020, a large increase from earlier years. This increase may, in part, reflect network upgrades made during the 2019 field season that replaced older analog sensors with broadband sensors capable of digital telemetry. This new instrumentation has proven more reliable at Great Sitkin Volcano than the older equipment, improving AVO’s ability to detect and locate earthquakes in the area. \r\n\"In late January 2020, Great Sitkin Volcano began to experience an increase in earthquake activity that was interpreted as unrelated to the recently improved seismic detection capabilities, prompting AVO to raise the Aviation Color Code and Volcano Alert Level to YELLOW and ADVISORY on February 26. This activity peaked in late March and then slowly declined throughout the remainder of 2020. In response to the declining rates of seismicity, the Aviation Color Code and Volcano Alert Level were lowered back to GREEN and NORMAL on October 21. No seismic or infrasound signals indicative of explosive events were detected at the volcano during 2020. \r\n\"The hypocenters of earthquakes at Great Sitkin Volcano in 2020 were principally clustered within the shallow crust, extending from the summit to roughly 10 km [6 mi] depth below sea level. Earthquakes were also recorded at depths between 10 and 35 km [6 and 22 mi]; these had waveforms and frequency contents suggesting both volcano-tectonic (VT) and deep LP events. Located events ranged in magnitude from ML -1.2 to ML 3.5. The ML 3.5 event occurred on March 6 (at 15:31 UTC; 05:31 HAST) under the east rim of the summit crater at a depth of 0.2 km [0.1 mi]. This earthquake was the strongest event recorded beneath Great Sitkin Volcano since its period of unrest began in 2016. For comparison, the largest earthquake recorded beneath the volcano’s edifice since monitoring began in 1999 was ML 4.3. That event took place on May 28, 2002, and was located beneath the southeast flank of the volcano (Pesicek and others, 2008). \r\n\"The other notable earthquake activity at Great Sitkin Volcano in 2020 consisted of a cluster of seven earthquakes that occurred between January 31 and February 1. These seven events ranged from ML -0.6 to 0.27 and had depths ranging from 22.6 to 27.0 km [14.0 to 16.8 mi]. \r\n\"AVO noted no major changes or unusual activity at the summit crater and dome during 2020, although the degree of visible steaming decreased compared to the 2016-2019 period (Dixon and others, 2020; Cameron and others, 2023; Orr and others, 2023). Photographs taken by passing airplanes in March, shortly after the ML 3.47 earthquake of March 6, show small snow-free areas and minor steaming at the summit of the volcano. Satellite imagery of Great Sitkin Volcano acquired in June and July indicated weakly elevated surface temperatures.\"","StartYear":2020,"StartMonth":2,"StartDay":26,"StartTime":null,"StartQualifier":1,"StartQualifierUnit":"Months","EndYear":2020,"EndMonth":10,"EndDay":21,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":4581,"Name":"Cleveland 2020/6","Description":"From Orr and others, 2024: \"Intermittent explosive eruptions have taken place [at Cleveland] every year since 2001. In 2020, Mount Cleveland had one confirmed explosion...\r\n\"[O]n June 2 at 06:31 UTC (June 1 at 21:31 HADT), a small explosion triggered the infrasound alarm in Adak, Alaska, and was detected shortly thereafter on the infrasound array in the City of Dillingham, Alaska. A small ash cloud was observed shortly afterward in satellite imagery drifting southward at an altitude of ~22,000 ft (~6,700 m). This event was the first explosion detected at Mount Cleveland since January 2019 - a span of 17 months and the longest repose period at the volcano since its onset of eruptive activity in 2001. In response, the Aviation Color Code and Volcano Alert Level were elevated to ORANGE and WATCH on June 2 at 07:46 UTC (June 1 at 22:46 HADT).\r\n\"The explosion destroyed ~60 percent of the 2019 dome, excavated and widened the crater slightly, and sent pyroclastic and debris flows as far as ~3 km [1.9 mi] down the flanks of the volcano. Hot debris landing on snow may have triggered some of these flows by melting and remobilizing mixtures of debris and snow. Satellite imagery acquired after the explosion also showed a trace ash deposit extending southward from the summit, discoloring the snow on the volcano’s flanks. Aerial photographs taken on June 3 showed that impact craters from ballistically ejected bombs and blocks dotted the snow, and satellite imagery acquired later showed that the ejecta reached as far as 1,400 m [4,600 ft] from the summit crater.\r\n\"Activity at Mount Cleveland diminished after the June 2 explosion. A weak steam plume dissipated after a few days, and no conspicuous degassing or definitive elevated surface temperatures were observed in satellite imagery thereafter through the rest of the year. Because of the lack of activity, the Aviation Color Code and Volcano Alert Level were downgraded to YELLOW and ADVISORY on June 17, then to UNASSIGNED on September 3, where the volcano stayed for the rest of the year.\"","StartYear":2020,"StartMonth":6,"StartDay":1,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2020,"EndMonth":6,"EndDay":1,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":4591,"Name":"Makushin 2020/6","Description":"From Orr and others, 2024: \"Seismic activity near Makushin Volcano increased beginning in the summer of 2020. An earthquake swarm kicked off on June 15 at 21:16 UTC (13:16 AKDT) with an earthquake of local magnitude (ML) 4.2 that was located ~12 km [7.5 mi] east-southeast of the volcano. This event was followed by hundreds of aftershocks in the same general area with several of ML 3–4, including a ML 4.1 earthquake on June 16 at 00:34 UTC (June 15 at 16:34 AKDT). The two ML 4 earthquakes and many of their aftershocks were felt strongly by residents of the City of Unalaska. The earthquake depths during this period ranged from 5 to 14 km. \r\nElevated seismicity near the volcano continued for the remainder of 2020, although the events gradually decreased in frequency over time. No other signs of unrest or surface deformation were observed at Makushin Volcano in remote sensing data, gas measurements, GNSS data, InSAR data, or webcam images. However, several deep long-period (LP) earthquakes (depths greater than 9 km [5.6 mi]) were recorded beneath the volcano’s summit prior to and during the June swarm. These LP events may represent magma movement in the lower crust, although such earthquakes are not unusual for Makushin Volcano. \r\n\"At the time of the swarm, AVO was uncertain whether the earthquake sources were related to tectonic or volcanic stresses. Therefore, on June 16, a seismic watch schedule was implemented, and the Aviation Color Code and Volcano Alert Level were raised to YELLOW and ADVISORY. On September 8, after seismic activity had returned to background levels and no other signs of volcanic unrest were observed, the Aviation Color Code and Volcano Alert Level were lowered back to GREEN and NORMAL. \r\n\"By analyzing the fault plane solutions of the earthquakes in the swarm, Lanza and others (2022) found that many of the larger earthquakes had P-axes oriented consistently with the regional maximum compression, but most of the smaller earthquakes had P-axes perpendicular to the regional maximum compression. On the basis of these findings, they concluded that the triggering mechanism of the earthquakes was most likely a combination of stresses from tectonic and magmatic sources along existing fault lines.\"","StartYear":2020,"StartMonth":6,"StartDay":15,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2020,"EndMonth":9,"EndDay":8,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Makushin","ParentVolcano":"Makushin","VolcanoID":"ak188","ParentVolcanoID":"ak188"},{"ID":4601,"Name":"Veniaminof 2020/6","Description":"From Orr and others, 2024: \"Mount Veniaminof did not erupt in 2020, but it did experience a period of elevated seismicity. Beginning on June 14, 2020, this seismicity was characterized by brief periods of continuous tremor (each lasting ~30 seconds to several minutes) and occasional earthquakes. Although no other signs of unrest were observed, this departure from the volcano’s background seismic activity prompted AVO to increase its Aviation Color Code and Volcano Alert Level to YELLOW and ADVISORY on June 18. The seismicity changed little until early August, when the level of tremor began to gradually decline. The decrease in seismic activity and the lack of evidence for surface change (no increased temperatures or gas emissions) indicated that activity at Mount Veniaminof had returned to background levels. As a result of these observations, AVO decreased the Aviation Color Code and Volcano Alert Level to GREEN and NORMAL on August 20.\"","StartYear":2020,"StartMonth":6,"StartDay":16,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2020,"EndMonth":8,"EndDay":20,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Veniaminof","ParentVolcano":"Veniaminof","VolcanoID":"ak301","ParentVolcanoID":"ak301"},{"ID":4863,"Name":"Novarupta ash resuspension 2020","Description":"From Orr and others, 2024: \"On September 14 (AKDT), strong winds entrained and resuspended ash from the Katmai region, carrying it northwestward at an altitude of ~4,000 ft (~1,200 m). Strong winds again picked up ash on October 31 (AKDT), carrying it southward at an altitude of ~5,000 ft (~1,500 m), as well as on November 2 (AKDT), carrying the ash southeastward at an altitude of ~5,000 ft (~1,500 m). During each resuspension event, the National Weather Service Alaska Aviation Weather Unit issued a significant meteorological weather advisory for aviators and AVO issued an information statement. The Aviation Color Code and Volcano Alert Level remained GREEN and NORMAL for Mount Katmai during 2020.\"","StartYear":2020,"StartMonth":9,"StartDay":14,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2020,"EndMonth":11,"EndDay":2,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Novarupta","ParentVolcano":"Novarupta","VolcanoID":"ak203","ParentVolcanoID":"ak203"},{"ID":4621,"Name":"Pavlof unrest 2020/9","Description":"AVO raised the Aviation Color Code and Volcano Alert Level for Pavlof to YELLOW/ADVISORY on September 21, 2020 (AKDT), citing ongoing increased seismicity over the previous 24 hours. Seismic unrest declined in October, and on October 14, 2020, AVO lowered the Aviation Color Code and Volcano Alert Level at Pavlof to GREEN/NORMAL.","StartYear":2020,"StartMonth":9,"StartDay":21,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":4631,"Name":"Korovin unrest 2020/10","Description":"From Orr and others, 2024: \"The first indication of unrest at Atka volcanic complex in 2020 was a small increase in seismic activity. This activity started in early June and culminated with episodic tremor on June 11-12. The amplitude of the tremor pulses, which each lasted 10-40 minutes, increased slowly and peaked on June 12 at ~13:50 UTC (~04:50 HADT). The tremor then subsided to background levels for the next several months. \r\n\"Beginning on October 15, the TROPOMI satellite instrument made occasional SO2 detections at Atka volcanic complex. These SO2 detections were the first at the complex in 2020 and indicated elevated volcanic degassing. An additional two satellite SO2 detections were made during the next two weeks, which also coincided with an increase in the number of earthquakes located in the area. In response to this heightened level of activity, AVO elevated the Aviation Color Code and Volcano Alert Level to YELLOW and ADVISORY on October 28. No additional satellite SO2 detections were made in the following weeks, and seismicity declined in late November, indicating a return to background activity. AVO subsequently lowered the Aviation Color Code and Volcano Alert Level back to GREEN and NORMAL on December 3.\"","StartYear":2020,"StartMonth":10,"StartDay":15,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2020,"EndMonth":12,"EndDay":3,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Korovin","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak171","ParentVolcanoID":"ak17"},{"ID":4865,"Name":"Shrub 2021","Description":"From Orr and others, 2024: \"New activity was also discovered at Shrub mud volcano’s summit when visited in 2022, made apparent by both a fresh tree-kill area upslope from (east of) the summit pit and new mud deposits that coated the pit’s east wall. The source of this mud was a string of recently opened springs that actively discharged hot, muddy water. This line of springs started at the north wall of the pit, extended southeastward and uphill to just below the summit, then stretched back down to the south wall of the pit. The most active of these new springs was a small, sputtering geyser ~20 centimeters (cm) [7.87 inches] high with a temperature of ~54 degrees Celsius (ºC) [~130 degrees Fahrenheit]. This temperature is the highest measured at Shrub mud volcano since 2000, before the summit pond formed. A few of the new springs were inactive, such as those on the barren slope above the south wall of the pit. \r\n\"The muddy water that filled the summit pit during previous field visits had been mostly replaced with more solid mud by the time of the 2021 field visit, probably owing to an influx of mud from the new springs on the slope above. Small, bubbling springs were distributed across this mud floor, but no dominant upwelling area existed in the remaining pond. This differs from previous visits, when workers observed a main upwelling area at the north end of the pond-in 2021, that area was covered in mud crossed by rivulets of warm water fed from upslope. The outflow stream discharge was also estimated to have increased by 3-4 times since the field visit in 2019.\"","StartYear":2021,"StartMonth":1,"StartDay":1,"StartTime":null,"StartQualifier":6,"StartQualifierUnit":"Months","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shrub","ParentVolcano":"Klawasi Group","VolcanoID":"ak253","ParentVolcanoID":"ak163"},{"ID":4651,"Name":"Semisopochnoi 2021/2","Description":"From Orr and others, 2024: \"Eruptive activity at Semisopochnoi Island, which began in September 2018, was characterized in 2021 by frequent, low-level ash emissions and explosions from the north cone of Mount Young. An equipment failure on Amchitka Island meant that activity observations during the first half of the year were limited to those from satellite imagery and regional infrasound and seismic stations. In early June 2021, the equipment on Amchitka Island was repaired and the local network on Semisopochnoi Island was completely upgraded. These upgrades involved a change from analog to digital telemetry; the replacement of short-period vertical-component seismometers with three-component broadband seismometers; the addition of broadband infrasound sensors at stations CERB, CESW, and CEPE; and the addition of webcams at stations CEPE and CETU. A six-element infrasound array was also installed on Amchitka Island in late May 2021 to provide improved regional monitoring. \r\n\"Seismic activity was low prior to the network outage; thus, the first activity noted in 2021 was a satellite observation of a small ash deposit from the north cone of Mount Young on February 6. In response, AVO raised the Aviation Color Code and Volcano Alert Level from UNASSIGNED to YELLOW and ADVISORY the next day. Ash emissions appeared in satellite imagery on February 8, which led AVO to further elevate the volcano to ORANGE and WATCH. \r\nIn the following months, satellites recorded intermittent ash emissions and regional infrasound sensors detected small explosions. Ash emissions increased considerably on April 16, when an ash cloud as high as ~20,000 ft (~6,100 m) ASL extended more than 350 km [220 mi] from the north cone of Mount Young. This change prompted AVO to raise the Aviation Color Code and Volcano Alert Level from ORANGE and WATCH to RED and WARNING. The next day, ash emissions declined and the volcano was lowered back to ORANGE and WATCH. Satellite imagery and regional infrasound sensors recorded intermittent, small explosions over the next few months. \r\n\"Seismicity was initially low after the local geophysical sensors were restored in June, but both seismicity and the number of discrete explosions increased into July and August. Seismic activity remained elevated, although variably so, for the rest of the year, during which time tremor and explosion signals dominated the data. On September 20, increased ash emissions observed in satellite imagery again prompted AVO to raise the Aviation Color Code and Volcano Alert Level from ORANGE and WATCH to RED and WARNING. A large SO2 cloud associated with this increase in activity appeared in TROPOMI satellite data. The following day, ash emissions declined, and Semisopochnoi Island was lowered to ORANGE and WATCH. The activity at the volcano for the rest of the year consisted of low-level ash emissions, seismic tremor, phreatomagmatic explosions, and many satellite SO2 detections. \r\n\"In combination with carrying out geophysical maintenance, AVO geologists sampled ash deposits on Semisopochnoi Island on May 30 and June 1. Tephra samples were collected across all parts of the island, but the samples most proximal to Mount Young, taken from a 4-cm-thick [1.6-in-thick] deposit, were from 1.6 km [1 mi] southwest of the center of the north cone. The tephra was fine-grained, easily remobilized, and present over the entire island except along the north coast. The coarsest grains in the samples were less than 4 mm [0.16 in] in diameter. Approximately 50 percent of the material was less than 50 micrometers [0.002 inches] in diameter. No larger ballistic particles were observed, including on the flanks of the north cone. The internal structures of deposits were not preserved; thus, the samples represent a bulk aggregate of deposits from throughout the spring of 2021. \r\n\"A microscopic analysis of the samples showed that they are mostly crystal-lithic grains or loose crystals. A minor proportion of the grains are scoriaceous juvenile material characterized by low vesicularity and microlitic glass. Microlite phases comprise plagioclase, clinopyroxene (augite and pigeonite), orthopyroxene, and iron-titanium oxides.\"\r\nFrequent low-level ash emissions and small explosions continued through the first half of 2022. Starting June 12, there was a pause in activity that led AVO to reduce the alert level and color code to YELLOW/ADVISORY on July 8, but they were increased again to ORANGE/WATCH on August 21, after a renewal of activity. On that day ash emissions reached almost 20,000 ft asl.\r\nMinor eruptive activity continued through mid-September. On September 29, AVO again lowered the color code and alert levels to YELLOW/ADVISORY due to an eruptive pause and a decline in seismic activity.\r\nStarting on October 31, a few small explosions occurred. This, along with tremor starting on November 5, led AVO to raise the alert levels to ORANGE/WATCH once more on November 7. A partial network outage starting that day reduced AVO's ability to track the eruption, but frequent steam plumes were observed in this period.\r\nDue to a lack of ash emissions or explosions, AVO reduced the alert levels to YELLOW/ADVISORY on November 23.\r\nOn December 27, webcam images showed fresh ash on the snow and a steam plume. The alert levels were raised to ORANGE/WATCH on December 28, 2022.\r\nAsh deposits and explosion signals continued into mid January, 2023. Steam plumes and seismic activity continued after that, but the lack of explosive activity caused AVO to lower the alert levels to YELLOW/ADVISORY on February 22, 2023.\r\nOn March 19, fresh ash was once again seen in webcam images, and explosions were detected. The alert levels were returned to ORANGE/WATCH. Minor eruptive activity continued through early May.\r\nOn May 17, the alert levels were lowered to YELLOW/ADVISORY.\r\nNo further eruptive activity was observed after this. Seismic activity declined to low levels as well. The alert levels were lowered to GREEN/NORMAL on August 3, 2023.","StartYear":2021,"StartMonth":2,"StartDay":6,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2023,"EndMonth":8,"EndDay":3,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Mount Young","ParentVolcano":"Semisopochnoi","VolcanoID":"ak44","ParentVolcanoID":"ak248"},{"ID":4661,"Name":"Veniaminof 2021/2","Description":"From Orr and others, 2024: \"Mount Veniaminof showed no indication of activity at the start of 2021. In response to a prolonged local seismic network outage that started in December 2020, AVO changed the volcano’s Aviation Color Code and Volcano Alert Level from GREEN and NORMAL to UNASSIGNED on January 15, 2021, reflecting the observatory’s limited ability to detect volcanic activity there. \r\n\"On March 1, the TROPOspheric Monitoring Instrument (TROPOMI) onboard the Copernicus Sentinel-5 Precursor satellite identified unrest at Mount Veniaminof in the form of elevated sulfur dioxide (SO2) emissions. The TROPOMI sensor measures variations in the wavelength-dependent absorption of ultraviolet energy due to the presence of gases (such as ozone and SO2) and retrieves the amount of gas present in the total atmosphere to account for the observed absorption. On March 2, satellite imagery again showed SO2. Elevated surface temperatures began to appear in satellite imagery early on March 4, and then a few hours later, at 05:13 AKST (14:13 UTC), regional infrasound instruments detected an explosion. Satellite imagery recorded a corresponding ash plume shortly thereafter. An ashy plume from cone A was seen in webcam imagery after sunrise, confirming that an eruption was underway. AVO responded later that morning by increasing the Aviation Color Code and Volcano Alert Level to ORANGE and WATCH. A retrospective analysis of high-resolution satellite imagery identified ash deposition near cone A and melting of glacial ice ~1 km [0.6 mi] to its east on February 28, but no signs of activity on February 25, suggesting that the eruption began between those two dates. Figure 18 [in reference] shows a timeline of the activity observed at Mount Veniaminof in 2021. \r\n\"The eruption reached its climax on March 4-10, producing moderately to strongly elevated surface temperatures, ash emissions, and frequent explosions detected by infrasound. Several explosions on March 6 were heard and even felt in Perryville, ~35 km [22 mi] away. Webcam and satellite data from this period showed ash emissions from cone A and a steam plume from the growing melt pit east of the cone. Between March 6 and March 10, the ash plumes reached as high as ~15,000 ft (~4,600 m) ASL and traveled as far as 220 km [140 mi] from the volcano. Owing to the height and extent of these ash plumes, local flight restrictions were set in place on March 9. Tephra deposits from the ash plumes were mostly confined to the caldera, but some ash fell outside the caldera on March 8, reaching as far as 22 km [14 mi] from the vent. The ash during this interval was blown predominantly southeastward.\r\n\"Lava effusion from vents within the glacial melt pit on the east flank of cone A first appeared in satellite imagery on March 7. The sub-circular melt pit continued to widen as the lava spread away from the flank vents and encompassed an area of nearly 700,000 square meters (m^2) [0.2 square miles] by late March.\r\nLess intense activity characterized the second half of March at Mount Veniaminof. Two seismic stations at the volcano came back online on March 12, allowing AVO geophysicists to detect tremor and LP earthquakes once again. Tremor was detected daily, whereas explosions and ash plumes were detected less frequently. Thermal anomalies from lava effusion were weaker in the second half of the month than in the first half. Lava effusion and minor ash emissions likely continued within the caldera throughout much of this time, although observations were limited to those on clear weather days. Ash plume altitudes remained lower than ~10,000 ft (~3,000 m) ASL. Although not reported, webcam imagery suggested that trace amounts of ash fell in Perryville on March 27, making it the only day during the eruption when a community may have been impacted by ash. \r\n\"On April 1, the eruption paused and the volcano showed only slightly elevated surface temperatures, which were probably related to cooling lava flows. The Aviation Color Code and Volcano Alert Level were lowered to YELLOW and ADVISORY on April 2 in response to this decreased activity. However, an ash plume on April 5 prompted AVO to raise the Aviation Color Code and Volcano Alert Level back to ORANGE and WATCH. A second ash plume was observed on April 6. No eruptive activity was observed thereafter, so the Aviation Color Code and Volcano Alert Level were lowered to YELLOW and ADVISORY on April 21, then back to UNASSIGNED on May 12. Elevated surface temperatures detected in the weeks after the pause were most likely related to a warm summit cone and cooling lava flows. Altogether, the three lava flows that erupted within the glacial melt pit covered a combined area of ~2.7×10^4 m^2 [2.9X10^5 sq ft] (Waythomas, 2021). \r\n\"AVO workers fully restored the Mount Veniaminof local seismic network during a field campaign in late June and early July. The Aviation Color Code and Volcano Alert Level were consequently changed to GREEN and NORMAL on July 8. Tremor, steam plumes, SO2 emissions, and thermal anomalies were detected in geophysical and remote sensing data shortly before and during the field campaign, which ran from June 28 to July 5. However, the field crew itself observed no noteworthy activity. No further unrest took place at Mount Veniaminof for the remainder of 2021. \r\n\"Tephra samples were collected from a snow pit ~2 km [~1.2 mi] east of cone A, adjacent to the melt pit, during the field campaign. Four distinct tephra layers were sampled; each consisted of black and red-oxidized grains intermixed with loose plagioclase crystals. Each layer had a modal grain size of 0.25–0.5 millimeter (mm) [0.01-0.02 in] and a maximum grain size of 2 mm [0.08 in]. One layer also had apparent accretionary lapilli. Petrographic analysis of the samples showed that the phenocrysts, like those sampled from the 2018 eruption (Loewen and others 2021), comprised normally zoned plagioclase, olivine, and rare clinopyroxene. The groundmass was a mixture of microlitic sideromelane, tachylyte, and lithic components. The glass composition was similar to that erupted in 2018, although with slightly lower silica concentrations (like the 2013 eruption glass).\"","StartYear":2021,"StartMonth":2,"StartDay":28,"StartTime":null,"StartQualifier":2,"StartQualifierUnit":"Days","EndYear":2021,"EndMonth":5,"EndDay":12,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Veniaminof","ParentVolcano":"Veniaminof","VolcanoID":"ak301","ParentVolcanoID":"ak301"},{"ID":4671,"Name":"Cleveland unrest 2021","Description":"From Orr and others, 2024: \"Early 2021 was quiet at Mount Cleveland, so the volcano remained at UNASSIGNED—the monitoring network was insufficient to locate earthquakes, so the volcano did not warrant a GREEN/NORMAL status. On March 10, however, an earthquake large enough to be detected 100 km away on Umnak Island took place near Mount Cleveland. This earthquake, combined with the detection of weak thermal anomalies and SO2 emissions starting the following week, suggested an increased potential for an eruption. In response, AVO raised the Aviation Color Code and Volcano Alert Level to YELLOW and ADVISORY on March 20. Soon afterward (March 26), an earthquake of local magnitude (ML) 4.3 took place near Mount Cleveland. \r\nHigh-resolution synthetic aperture radar (SAR) data spanning March 9 to March 20 recorded slight subsidence within the crater, which seemed to correlate with the appearance of elevated surface temperatures and gas emissions there. The crater was previously floored by cold rubble, so subsidence above the conduit may have formed openings that allowed heat and gases to escape more readily. Near-infrared temperatures in the crater rose above 600 ºC [1100 ºF], indicating magma near the surface. \r\n\"Detections of thermal anomalies, SO2 emissions, a summit plume, and crater floor subsidence continued with little change over the next several months. However, by late summer, signs of unrest had declined: the volcano had quieted seismically, subsidence had ceased, gas emissions were no longer being detected, and thermal anomalies had declined in both strength and frequency. In response to this dwindling activity, AVO changed the Aviation Color Code and Volcano Alert Level to UNASSIGNED on October 20. Detections of elevated surface temperatures continued occasionally through the end of the year, but activity at the volcano overall remained low.\"","StartYear":2021,"StartMonth":3,"StartDay":17,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2021,"EndMonth":10,"EndDay":20,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":4671,"Name":"Cleveland unrest 2021","Description":"From Orr and others, 2024: \"Early 2021 was quiet at Mount Cleveland, so the volcano remained at UNASSIGNED—the monitoring network was insufficient to locate earthquakes, so the volcano did not warrant a GREEN/NORMAL status. On March 10, however, an earthquake large enough to be detected 100 km away on Umnak Island took place near Mount Cleveland. This earthquake, combined with the detection of weak thermal anomalies and SO2 emissions starting the following week, suggested an increased potential for an eruption. In response, AVO raised the Aviation Color Code and Volcano Alert Level to YELLOW and ADVISORY on March 20. Soon afterward (March 26), an earthquake of local magnitude (ML) 4.3 took place near Mount Cleveland. \r\nHigh-resolution synthetic aperture radar (SAR) data spanning March 9 to March 20 recorded slight subsidence within the crater, which seemed to correlate with the appearance of elevated surface temperatures and gas emissions there. The crater was previously floored by cold rubble, so subsidence above the conduit may have formed openings that allowed heat and gases to escape more readily. Near-infrared temperatures in the crater rose above 600 ºC [1100 ºF], indicating magma near the surface. \r\n\"Detections of thermal anomalies, SO2 emissions, a summit plume, and crater floor subsidence continued with little change over the next several months. However, by late summer, signs of unrest had declined: the volcano had quieted seismically, subsidence had ceased, gas emissions were no longer being detected, and thermal anomalies had declined in both strength and frequency. In response to this dwindling activity, AVO changed the Aviation Color Code and Volcano Alert Level to UNASSIGNED on October 20. Detections of elevated surface temperatures continued occasionally through the end of the year, but activity at the volcano overall remained low.\"","StartYear":2021,"StartMonth":3,"StartDay":17,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2021,"EndMonth":10,"EndDay":20,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":4866,"Name":"Spurr non-eruptive activity 2021","Description":"From Orr and others, 2024: \"Although no eruptive activity or unrest took place at Mount Spurr in 2021, one notable ice and rock avalanche was large enough to be recorded by regional geophysical sensors. This mass movement signal was recorded on Mount Spurr’s local seismic network on April 7 at 05:22 AKDT (13:22 UTC). The event's seismic waveforms indicated that it had a duration of ~2 minutes. Acoustic waves were likewise detected at station SPCP (on Mount Spurr) and at KENI infrasound array (near the City of Kenai, Alaska); these waves also had a coherent signal duration of ~2 minutes. No clear satellite views were available for this event, precluding AVO from identifying a precise source or deposit area and estimating the avalanche volume. However, the peak period of the long-period (LP) seismic energy was ~15 seconds, indicating that the event was smaller than the widely recorded Mount Spurr ice and rock avalanche of July 15, 2019 (Orr and others, 2023).\"","StartYear":2021,"StartMonth":4,"StartDay":7,"StartTime":"13:22:00","StartQualifier":null,"StartQualifierUnit":null,"EndYear":2021,"EndMonth":4,"EndDay":7,"EndTime":"13:24:00","EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Spurr","ParentVolcano":"Spurr","VolcanoID":"ak260","ParentVolcanoID":"ak260"},{"ID":4781,"Name":"Gareloi 2021 unrest","Description":"From Orr and others, 2024: \"Beginning on May 18, 2021, anomalous seismicity was recorded at the Mount Gareloi. In particular, the low-energy LP events commonly observed at the volcano overlapped with a harmonic tremor recorded on every station on the island. The dominant tremor frequencies peaked at ~3.4 hertz (Hz), ~6.4 Hz, ~8.3 Hz, and ~10.7 Hz. These harmonic signals, which were intermittent during at least the previous day, became conspicuous after a regional ML 5.0 earthquake at 20:42 HADT on May 17 (05:42 UTC on May 18), though this change might be coincidental. Harmonic tremor took place intermittently until May 27, when highly frequent and highly energetic LP events emerged, sometimes merging into continuous broadband tremor. An ~2-Hz infrasound signal was also recorded locally on June 3, although it was unclear if the signal was of volcanic origin. A monochromatic, ~7 Hz seismic signal lasting 15-20 min was recorded on June 6, while elevated-amplitude seismicity, ongoing since about May 27, continued. Hence, on June 8, AVO raised the Aviation Color Code and Volcano Alert Level to YELLOW and ADVISORY. The increase in seismic activity likely reflected a change to the magmatic-hydrothermal system interaction. No indications of unrest, however, were observed by an AVO field crew that flew over the summit on May 23. \r\n\"Over the following two months, the elevated and anomalous seismicity continued intermittently; SO2 was detected in satellite imagery but was consistent with measurements from the last several years; light steaming was observed in partly cloudy satellite and webcam views of the volcano; and weakly elevated surface temperatures were sometimes observed in satellite data. No eruptive activity was observed in satellite views of the volcano and no activity was detected by local or regional infrasound sensors. Starting in the second week of July, seismic activity gradually diminished and returned to background levels. AVO lowered the Aviation Color Code and Volcano Alert Level to GREEN and NORMAL on July 28, 2021.\"","StartYear":2021,"StartMonth":5,"StartDay":18,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2021,"EndMonth":7,"EndDay":28,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Gareloi","ParentVolcano":"Gareloi","VolcanoID":"ak106","ParentVolcanoID":"ak106"},{"ID":4771,"Name":"Great Sitkin 2021/05","Description":"From Orr and others, 2024: \"Great Sitkin Volcano erupted in 2021 after a period of seismic unrest and minor steam explosions that began in 2016 (for example, Dixon and others, 2020). \r\n\"Leading up to 2021, activity at Great Sitkin Volcano was characterized by years of precursory seismicity, elevated surface temperatures, and gas emissions. This unrest culminated with a Vulcanian explosion on May 25, 2021, an event successfully forecasted by AVO in the hours prior. An effusive eruption then began in mid-July, gradually filling both the 2021 explosion crater and much of the summit crater with lava, which then spilled down the volcano’s flanks. Lava effusion persisted at the volcano throughout the rest of the year. The 2021 eruption followed the pattern of the 1974 eruption: an explosive event followed by lava effusion in the summit crater. AVO crews visited the volcano in June 2021 to sample the explosive eruption deposits and to carry out a gas and airborne imaging survey. \r\n\"2016-2021 Precursory Unrest \r\n\"Volcanic unrest began at Great Sitkin Volcano in July 2016 and was characterized by elevated seismicity, anomalous steam emissions from the summit crater, and a few small explosive events. The thousands of small earthquakes detected between 2016 and 2021 were located primarily in the shallow crust (between the surface and ~10 km [~6 mi] depth) and had ML values of less than 3 (for example, Dixon and others, 2020). The elevated seismicity at Great Sitkin Volcano began waning in early 2020 and had declined to background levels before the end of that year, leading AVO to lower the Aviation Color Code and Volcano Alert Level to GREEN and NORMAL on October 21, 2020. \r\n\"In January 2021, AVO observed a slight elevation of surface temperatures within the summit crater. More signs of activity began appearing that spring: earthquakes were recorded at an increasing frequency, satellite observations increasingly showed weakly to moderately elevated surface temperatures, and TROPOMI sensors began detecting SO2 emissions. This increasing unrest led AVO to raise the Aviation Color Code and Volcano Alert Level to YELLOW and ADVISORY on May 12.\r\n\"May 25 Explosion \r\n\"An earthquake swarm began on May 24, and the earthquake rate steadily increased, which indicated an increased potential for eruptive activity. This led AVO to raise the Aviation Color Code and Volcano Alert Level to ORANGE and WATCH on May 25. Great Sitkin Volcano produced an explosion one hour and 39 minutes later, at 20:04 HADT on May 25 (05:04 UTC on May 26), sending an ash and gas plume northeastward at an elevation of ~15,000 ft (~4,600 m) ASL. The ~2-minute-long explosion was detected in seismic, infrasound, and satellite data, as well as by local observers. The eruption and resulting ash cloud led AVO to raise the Aviation Color Code and Volcano Alert Level to RED and WARNING at 20:30 HADT on May 25 (05:30 UTC on May 26). After a decline in seismic activity and cessation of ash emissions, AVO lowered the Aviation Color Code and Volcano Alert Level to ORANGE and WATCH at 07:31 HADT (16:31 UTC) on May 26. A continued lack of eruptive activity accompanied by a decrease in seismicity, surface temperatures, and steam emissions led AVO to further reduce the Aviation Color Code and Volcano Alert Level to YELLOW and ADVISORY on May 27.\r\n\"Characterization of the May 25 Eruption \r\n\"Analysis of geophysical, geological, and remote sensing data suggest that the May 25 explosion of Great Sitkin Volcano was a Vulcanian eruption. The event produced high-amplitude infrasound (~190 pascals [0.0019 bar] at 6 km [4 mi] distance) and was preceded by a slow pressure rise, a phenomenon that is consistent with other Vulcanian explosions and is caused by pre-explosion inflation of a dome or plug feature (for example, Yokoo and others, 2009; Iezzi and others, 2020). The explosion infrasound signal also showed two peaks in pressure that were likely related to a multi-part failure of the dome. After the main explosion, lower-amplitude infrasound emissions were recorded for tens of seconds. The explosion produced an ash cloud that quickly detached and drifted northeastward before dispersing. The next day, TROPOMI data showed an SO2 plume over the Bering Sea consistent with the eruptive cloud’s trajectory. The explosion also widened the pre-existing explosion crater in the 1974 dome, blasting large blocks (wider than 2 m [6.6 ft]) of old, altered lavas into a radial ballistic field ~1.5 km [~1 mi] in diameter. Some likely landed warm because they were found in deep melt pits when observed later by AVO geologists. Other eruptive deposits were a trace tephra deposit extending 5 km [3 mi] east-southeast, dark pyroclastic surge deposits ~1 km [0.6 mi] long, and a lahar that extended 2 km [1.2 mi] downslope to the south. Extending between the lahar starting point at the southeast crater rim and the vent within the crater was a 600-m-long [2,000-ft-long], pyroclastic flow deposit made of large, altered blocks, some more than 3 m [10 ft] in diameter. The deposits of the May 25 explosion were mapped with high-resolution optical and thermal imagery and sampled by an AVO field team on June 11.\r\n\"The eruption samples showed that the tephra deposit was primarily lithic and coarse-grained with rare juvenile breadcrust bombs (less than 1 percent of the deposit). The breadcrust bombs have a bulk andesite composition comprising a matrix of high-silica (rhyolitic?) glass and phenocrysts of highly zoned plagioclase, clinopyroxene, orthopyroxene, magnetite, and apatite. The high crystallinity, presence of both apatite and a silica groundmass phase, and evolved interstitial melt composition all suggest that the erupted magma was a shallow, low-pressure, and near-solidus magma plug. The coarse-grained, poorly sorted, and lithic-rich deposit characteristics also support a Vulcanian eruption mechanism, which is consistent with geophysical observations and photographs of the eruption event.\r\n\"2021 Effusive Phase \r\n\"After the May 25 explosion, seismicity and elevated surface temperatures were regularly recorded at the volcano, consistent with post-explosion fumarolic activity observed in a thermal survey on June 11. Steaming, elevated surface temperatures, and SO2 emissions were observed through mid-July. On July 23, high-resolution TerraSAR-X spotlight SAR imagery showed a small, new lava dome in the center of the explosion crater. No lava was present in previous imagery from July 14, so lava effusion began sometime during the period of July 14-23. In response to the onset of effusion, AVO raised the Aviation Color Code and Volcano Alert Level to ORANGE and WATCH on July 23. \r\n\"Lava overflowed the explosion crater by August 4, spreading radially over the 1974 and 1945 lava domes and onto the ice that filled the east part of the summit crater. The lava effusion in July and August was accompanied by steam and SO2 emissions; incandescence; saturated SWIR and midinfrared satellite data; and elevated seismicity. Lava effusion rates were 3-7 cubic meters per second (m^3/s) [100-250 cubic feet per second (ft^3/s)] in August as estimated by mapping the flow extent and thickness. This mapping was produced using high-resolution optical and radar satellite imagery, as well as the thermal radiative power measured by the Moderate Resolution Imaging Spectroradiometer and Visible Infrared Imaging Radiometer Suite (satellite sensors). The effusion rate declined after August, dropping to ~2 m^3/s [70 ft^3/s] in September and falling below 1 m^3/s [35 ft^3/s] in November. Seismicity and SO2 emissions also waned when effusion rates declined in September. \r\n\"Lava began to overflow the summit crater in September, eventually forming three flow lobes that advanced down the steep flanks of the volcano: a west lobe that started by September 19, a south lobe that started by September 29, and a north lobe that started by November 12. The flow fronts had minor rockfall activity, depositing blocks as far as ~50 m [~150 ft] below the flow front. The east flow margin advanced onto the ice, melting it and causing fracturing and collapse of the ice near the flow front, but only producing minor steaming. By the end of 2021, the lava flow covered 1.3 square kilometers [0.5 square miles] and had an estimated total volume of 0.031 km^3 [0.0074 mi^3]. The dome within the summit crater was ~1,230 m [~4030 ft] wide (in its east-west direction), whereas the west, south, and north flow lobes were ~830 [2700], ~865 [2840], and ~180 m [590 ft] long, respectively. Slow effusion continued into 2022. \r\n\"During 2021, AVO located 966 earthquakes near Great Sitkin Volcano, ranging in ML from −1.1 to 2.1 and in depth from −1.8 to 32.04 km below sea level (negative depths reflect height above sea level). Most hypocenters clustered between 0 and 10 km [0-6 mi] depth beneath the Great Sitkin Volcano edifice. The most notable seismicity during 2021 was a ~24-hour-long swarm of LP [long period] earthquakes that immediately preceded the explosive eruption on May 25.\"\r\nSlow lava emissions continued over the next several months, with weak seismicity and elevated surface temperatures observed in clear weather. Steam and gas plumes were occasionally observed. By mid-February 2022, the southern lava flow was 3400 ft long, the western lava flow was 3000 ft long, and the northern lava flow was 720 ft long. After this, the southern and western lava flows were occasionally observed to grow longer. In May and June, most new lava was confined to the crater rather than the lava flows. \r\nIn mid-2022, the lava began slowly advancing eastward in the crater as well as piling up on top of the vent. This marked the start of a new phase of the eruption, as the previous lava flows on the flanks stopped growing and new lava flows were established within the crater. Initially these new flows travelled south and east of the vent.  By November 4, 2022, the new flows had extended 2000 feet to the east and 1400 feet to the south. Weak seismicity and sometimes elevated surface temperatures continued through this period.\r\nInto the beginning of 2023, the lava flow field continued to grow in the eastern direction, interacting with the inter-crater icefield. Some flows also traveled south on top of the cooler lava flows from the first phase of the eruption, but by April 2023, the only growth direction was eastward. As the lava flow plowed into the inter-crater glacier, the ice deformed and cracked. Low-level seismicity, somewhat elevated surface temperatures, and steaming from around the vent location all continued throughout the rest of the year.\r\nAVO scientists visited the lava flow in September 2023 and took samples. They found the flows were warm and steaming. At the time, the active part of the flow was advancing about a foot every day.\r\nIn December 2023, new uplift of the lava on top of the vent location was noted, which caused radial cracks to form on the surface of the flow.\r\nIn early January 2023, the upward movement over the vent continued, which pushed some material to the north. Lava began flowing in a northward direction from the vent, reaching the northern margin of the previous 2021 flow by January 12. Lava activity remained restricted to the center of the active summit lava dome, with little advancement of its outer margins in the next week.\r\nOn January 2, the data streams from all instruments on Great Sitkin went down due to weather, and the outage continued until January 28. AVO used satellite data and regional infrasound to track eruptive activity during this time.\r\nOn January 24, satellite radar data showed that the new northwestward-moving lobe of the lava flow had extended about 600 feet from the northernmost of the radial cracks that had been noted in December.\r\nExtrusion of the northwest lobe continued throughout February.\r\nOn March 6, satellite radar data showed some movement of the eastern lobe, but other observations during the rest of March showed extrusion had returned to the newer northwest lobe, along with additional uplift over the vent region. High-resolution satellite images showed the northwest lobe mostly snow-free, indicating its warmth, and steaming at the vent.\r\nIn the first half of April, both the northwestern and eastern lobes grew, but in the latter half of April through mid-May only the northwestern lobe continued to grow. By April 12, it had reached 850 ft (260 m) in length. The active part of the lava flow was observed to be snow-free and steaming when clear satellite views allowed.\r\nIn the later part of May northward flow continued, but more lava also uplifted the surface above the location of the vent. This pattern continued through the early part of July, with occasional detections of elevated temperatures over the surface of the flow and observations of steaming when the weather was clear.\r\nIn mid-July flow direction moved to the east and south, with new lava covering flows from 2021-2024. Rock falls occurred as cooled lava blocks fell down the steep margins of the flow, creating seismic signals.\r\nThis activity continued into early August. Lava flow direction was mainly to the east-northeast, with elevated surface temperatures and steaming observed in clear weather. Late in August the flow direction became more to the northeast, but in mid-September was more to the east. Weak thermal anomalies continued to be observed through mid-October.\r\nIn November, lava activity was mainly near the vent location, with a small amount of activity at the northern margins of the flow. Occasional volcanic earthquakes continued, with occasional sights of steaming or thermal anomalies when clear weather was present.\r\nLava extrusion continued without much change through mid-April 2025. In the latter half of April flow was more to the east and southeast, and inflation of the southeast portion of the lava dome occurred as well.\r\nDuring May-January 2026, satellite radar images showed growth of the lava dome. The flow expanded slightly to the south and thickened over the vent. Occasional rockfalls were noted in seismic data off the dome and flow. Steaming and elevated surface temperatures were occasionally observed when weather allowed.\r\nThe alert levels have remained at ORANGE/WATCH since July 23, 2021.","StartYear":2021,"StartMonth":5,"StartDay":25,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Great Sitkin","ParentVolcano":"Great Sitkin","VolcanoID":"ak111","ParentVolcanoID":"ak111"},{"ID":4791,"Name":"Pavlof 2021/08","Description":"From Orr and others, 2024: \"After a 9-month quiescent period that started in late 2020, seismic activity at Pavlof Volcano increased on July 9, 2021, in a distinct change from its background levels. Tremor periods observed on that date prompted AVO to increase the Aviation Color Code and Volcano Alert Level from GREEN and NORMAL to YELLOW and ADVISORY. From July 9 to August 5, seismic activity at the volcano was characterized by more volcanic tremor periods and occasional low frequency events, but no outward signs of eruptive activity were observed. \r\n\"On August 5, 2021, clear webcam views of Pavlof Volcano showed episodic, low-level ash emissions. These intermittent ash bursts came from a new vent on the upper southeast flank of the volcano, which produced diffuse ash clouds that rose just above the summit and drifted roughly 10-15 km [6-9 mi] southeastward before dissipating. Seismic and infrasound data associated this activity with occasional small explosions and tremor. The ash emissions clearly indicated that an active eruption was in progress, so AVO raised the Aviation Color Code and Volcano Alert Level to ORANGE and WATCH later that day. \r\n\"Seismic and infrasound sensors regularly recorded small explosions through the rest of the year, and when viewing conditions permitted, minor ash emissions appeared in webcam views and were observed by pilots. Diffuse ash clouds intermittently rose as high as ~12,000 ft (~3,700 m) ASL and were visible in satellite data as far as 10-15 km [6-9 mi] beyond the vent. Ash fallout during this period settled mainly on the upper south-southeast flank of the volcano, within 2-3 km [1.2-1.9 mi] of the vent. Occasional stronger ash bursts and farther-traveling ash clouds may have produced trace amounts (less than 1/32 inch or 0.8 mm) of ash fall as far as 10-15 km [6-9 mi] southeast of the vent, but this amount of ash is difficult to observe in satellite data and so could not be confirmed. \r\nOn August 25 and 26, mid-infrared satellite images showed slightly elevated surface temperatures at the summit of the volcano for the first time. The detection of elevated surface temperatures in satellite data usually indicates that lava is at or near the surface; however, lava flows at Pavlof Volcano were not confirmed until November 8, when the thermal output at the vent increased considerably. The presence of shallow subsurface magma and hot gases may have contributed to the slightly elevated thermal signals observed between late August and early November. \r\n\"Satellite images acquired on November 11 showed an active lava flow or spatter accumulation, about 200 m in length, and associated lahar deposits (extending ~2 km [~1.2 mi] beyond the vent) on the upper southeast flank of the volcano. Many historical eruptions of Pavlof Volcano have been characterized by lava fountaining or jetting that result in the accumulation of spatter around the vent. Occasionally, these growing spatter piles become unstable and collapse, forming hot particulate flows that are capable of eroding and melting glacier ice and snow on the volcano. The formation of meltwater by this process is a primary mechanism for lahar generation at Pavlof Volcano (Waythomas and others, 2017). The eruptive activity in early November may have been characterized by such periods of lava fountaining, spatter accumulation, and the extrusion of hot, granular flows that produced the lahar deposits observed in satellite imagery. A Sentinel-2 short-wave infrared (SWIR) image from November 12 showed a circular area of hot material around the active vent, consistent with the notion that spatter accumulation had been occurring. However, none of the webcam views or occasional pilot reports from November and December confirmed incandescence or lava fountaining at the south flank vent. \r\n\"On November 17, satellite observations indicated both the presence of ballistic clasts around the vent (some located as far as 2.5 km [1.6 mi] away) and continued lahar development that was likely associated with ongoing lava-ice-snow interaction. The ballistic clasts were ejected during energetic explosions that were recorded in seismic and infrasound data during the week of November 12-18. Minor explosions and small ash emissions took place occasionally during the last two weeks of November 2021, although the volcano was obscured by clouds for much of this period. \r\n\"From late November through December, the Pavlof Volcano seismic network detected elevated seismicity consisting of episodic, sustained tremor periods and discrete low-frequency events. Many explosions were detected in seismic and infrasound data—these may have produced localized ballistic ejecta fallout around the active vent, as indicated by satellite data acquired on December 1, 2021. On December 4, a webcam and a passing aircraft recorded minor ash emissions that rose from the summit of the volcano to an altitude of ~10,000 ft (~3,000 m) ASL. Satellite data from this period also commonly indicated moderately to strongly elevated surface temperatures. High-resolution satellite imagery collected during clear weather commonly showed lava effusion on the upper southeast flank of the volcano, as well as continued interaction with snow and ice that subsequently produced small lahars downslope from the lava flows. For instance, satellite images obtained on December 19, 2021, showed both an ~600-m-long [~2,000-ft-long] lava flow and minor lahar deposits that extended ~1,300 m [~4,300 ft] beyond the flow front.\"\r\nPavlof remained at Aviation Color Code ORANGE for much of 2022, with intermittent lava effusion, small explosions, and low-level ash emissions. On December 17, 2022, AVO lowered the Aviation Color Code and Volcano Alert Level at Pavlof from ORANGE/WATCH to YELLOW/ADVISORY, stating that no explosions had been detected since December 11, 2022, and no elevated surface temperatures or incandescent lava since December 2, 2022. On January 19, 2023, AVO lowered the Aviation Color Code and Volcano Alert Level to GREEN/NORMAL.","StartYear":2021,"StartMonth":7,"StartDay":9,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2022,"EndMonth":12,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":4791,"Name":"Pavlof 2021/08","Description":"From Orr and others, 2024: \"After a 9-month quiescent period that started in late 2020, seismic activity at Pavlof Volcano increased on July 9, 2021, in a distinct change from its background levels. Tremor periods observed on that date prompted AVO to increase the Aviation Color Code and Volcano Alert Level from GREEN and NORMAL to YELLOW and ADVISORY. From July 9 to August 5, seismic activity at the volcano was characterized by more volcanic tremor periods and occasional low frequency events, but no outward signs of eruptive activity were observed. \r\n\"On August 5, 2021, clear webcam views of Pavlof Volcano showed episodic, low-level ash emissions. These intermittent ash bursts came from a new vent on the upper southeast flank of the volcano, which produced diffuse ash clouds that rose just above the summit and drifted roughly 10-15 km [6-9 mi] southeastward before dissipating. Seismic and infrasound data associated this activity with occasional small explosions and tremor. The ash emissions clearly indicated that an active eruption was in progress, so AVO raised the Aviation Color Code and Volcano Alert Level to ORANGE and WATCH later that day. \r\n\"Seismic and infrasound sensors regularly recorded small explosions through the rest of the year, and when viewing conditions permitted, minor ash emissions appeared in webcam views and were observed by pilots. Diffuse ash clouds intermittently rose as high as ~12,000 ft (~3,700 m) ASL and were visible in satellite data as far as 10-15 km [6-9 mi] beyond the vent. Ash fallout during this period settled mainly on the upper south-southeast flank of the volcano, within 2-3 km [1.2-1.9 mi] of the vent. Occasional stronger ash bursts and farther-traveling ash clouds may have produced trace amounts (less than 1/32 inch or 0.8 mm) of ash fall as far as 10-15 km [6-9 mi] southeast of the vent, but this amount of ash is difficult to observe in satellite data and so could not be confirmed. \r\nOn August 25 and 26, mid-infrared satellite images showed slightly elevated surface temperatures at the summit of the volcano for the first time. The detection of elevated surface temperatures in satellite data usually indicates that lava is at or near the surface; however, lava flows at Pavlof Volcano were not confirmed until November 8, when the thermal output at the vent increased considerably. The presence of shallow subsurface magma and hot gases may have contributed to the slightly elevated thermal signals observed between late August and early November. \r\n\"Satellite images acquired on November 11 showed an active lava flow or spatter accumulation, about 200 m in length, and associated lahar deposits (extending ~2 km [~1.2 mi] beyond the vent) on the upper southeast flank of the volcano. Many historical eruptions of Pavlof Volcano have been characterized by lava fountaining or jetting that result in the accumulation of spatter around the vent. Occasionally, these growing spatter piles become unstable and collapse, forming hot particulate flows that are capable of eroding and melting glacier ice and snow on the volcano. The formation of meltwater by this process is a primary mechanism for lahar generation at Pavlof Volcano (Waythomas and others, 2017). The eruptive activity in early November may have been characterized by such periods of lava fountaining, spatter accumulation, and the extrusion of hot, granular flows that produced the lahar deposits observed in satellite imagery. A Sentinel-2 short-wave infrared (SWIR) image from November 12 showed a circular area of hot material around the active vent, consistent with the notion that spatter accumulation had been occurring. However, none of the webcam views or occasional pilot reports from November and December confirmed incandescence or lava fountaining at the south flank vent. \r\n\"On November 17, satellite observations indicated both the presence of ballistic clasts around the vent (some located as far as 2.5 km [1.6 mi] away) and continued lahar development that was likely associated with ongoing lava-ice-snow interaction. The ballistic clasts were ejected during energetic explosions that were recorded in seismic and infrasound data during the week of November 12-18. Minor explosions and small ash emissions took place occasionally during the last two weeks of November 2021, although the volcano was obscured by clouds for much of this period. \r\n\"From late November through December, the Pavlof Volcano seismic network detected elevated seismicity consisting of episodic, sustained tremor periods and discrete low-frequency events. Many explosions were detected in seismic and infrasound data—these may have produced localized ballistic ejecta fallout around the active vent, as indicated by satellite data acquired on December 1, 2021. On December 4, a webcam and a passing aircraft recorded minor ash emissions that rose from the summit of the volcano to an altitude of ~10,000 ft (~3,000 m) ASL. Satellite data from this period also commonly indicated moderately to strongly elevated surface temperatures. High-resolution satellite imagery collected during clear weather commonly showed lava effusion on the upper southeast flank of the volcano, as well as continued interaction with snow and ice that subsequently produced small lahars downslope from the lava flows. For instance, satellite images obtained on December 19, 2021, showed both an ~600-m-long [~2,000-ft-long] lava flow and minor lahar deposits that extended ~1,300 m [~4,300 ft] beyond the flow front.\"\r\nPavlof remained at Aviation Color Code ORANGE for much of 2022, with intermittent lava effusion, small explosions, and low-level ash emissions. On December 17, 2022, AVO lowered the Aviation Color Code and Volcano Alert Level at Pavlof from ORANGE/WATCH to YELLOW/ADVISORY, stating that no explosions had been detected since December 11, 2022, and no elevated surface temperatures or incandescent lava since December 2, 2022. On January 19, 2023, AVO lowered the Aviation Color Code and Volcano Alert Level to GREEN/NORMAL.","StartYear":2021,"StartMonth":7,"StartDay":9,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2022,"EndMonth":12,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":4870,"Name":"Aniakchak ash resuspension 2021","Description":"From Orr and others, 2024: \"When the landscape near Aniakchak Crater is snow-free, and particularly when the ground has little moisture content, strong winds can pick up ash and create large ash clouds. The wind can then transport this resuspended ash, which can pose a hazard to aviation. On August 1-2, 2021, strong southerly winds entrained and resuspended ash from the region north of Aniakchak Crater and east of Port Heiden before carrying it ~200 km [~120 mi] northward over Bristol Bay. High-resolution satellite views indicated that the event’s source region was north of the caldera at the sparse surface exposures of pyroclastic-flow deposits from the caldera-forming eruption. The drifting ash cloud appeared in imagery from the Geostationary Operational Environmental Satellite for ~18 hours beginning late in the morning on August 1. Groundlevel webcam views from Port Heiden also recorded this resuspended ash. In response, AAWU issued a SIGMET for aviators and AVO issued an Information Statement. AVO received no reports of ashfall at Port Heiden. The Aviation Color Code and Volcano Alert Level remained GREEN and NORMAL for Aniakchak Crater during 2021.\"","StartYear":2021,"StartMonth":8,"StartDay":1,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2021,"EndMonth":8,"EndDay":2,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":4867,"Name":"Iliamna avalanche 2021","Description":"From Orr and others, 2024: \"A large ice and rock avalanche took place on the east flank of Iliamna Volcano on August 5, 2021, at 07:21 AKDT (15:21 UTC). Afterward, satellite imagery and oblique aerial photographs showed a dark-colored flow deposit on Iliamna Volcano’s east-facing Red Glacier. This avalanche initiated less than 1 km [0.6 mi] from the volcano’s summit and traveled at least 4 km almost due east, generating seismic and acoustic signals recorded locally and regionally. High-frequency signals were clearly recorded on Iliamna Volcano’s seismic network. Farther away, the KENI infrasound array at Kenai, and the HOM infrasound station in the City of Homer, Alaska, detected acoustic waves from the event. \r\n\"Red Glacier has hosted many avalanches historically and prehistorically (Waythomas and others, 2000); the most recent ice and rock avalanche of comparable size to this event occurred in June 2019 (Toney and others, 2021; Orr and others, 2023). These mass flows are generally composed of mostly ice and snow with smaller amounts of rock (involved through entrainment or as part of the original failure region). Avalanches on Red Glacier are highly mobile, traveling at mean speeds of ~50 meters per second (m/s) [~110 miles per hour] (CaplanAuerbach and Huggel, 2007) and peak speeds, estimated via numerical modeling and seismic force inversion, of greater than (\u003e) 70 m/s [160 miles per hour] (Schneider and others, 2010; Toney and others, 2021). Judging by the size of the deposit and the amplitudes of the seismic and infrasound signals, the August 2021 event appears to be smaller than the June 2019 ice and rock avalanche.\"","StartYear":2021,"StartMonth":8,"StartDay":5,"StartTime":"15:21:00","StartQualifier":null,"StartQualifierUnit":null,"EndYear":2021,"EndMonth":8,"EndDay":5,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Iliamna","ParentVolcano":"Iliamna","VolcanoID":"ak124","ParentVolcanoID":"ak124"},{"ID":4801,"Name":"Atka 2021 unrest","Description":"From Orr and others, 2024: \"Beginning on August 10, 2021, AVO detected a swarm of earthquakes at Atka volcanic complex that lasted several days before tapering off. In response to this local seismicity, AVO raised the Aviation Color Code and Volcano Alert Level to YELLOW and ADVISORY on August 11. \r\n\"AVO analysts located 204 earthquakes between August 10 and 12; these events had epicenters approximately 3-9 km [2-6 mi] west-southwest of Mount Kliuchef and typical depths of 2-5 km [1.2-3 mi] below sea level. The largest earthquake took place on August 11 and had an ML of 2.5. Five other earthquakes exceeded ML 2.0. The rate of earthquakes began to decline after August 12 and returned to background levels by the end of the month. In response, AVO changed the Aviation Color Code and Volcano Alert Level of Atka volcanic complex to GREEN and NORMAL on August 27. Satellite imagery and infrasound sensors detected no anomalous activity or unrest around the time of the earthquake swarm, in contrast with observations from October 2020, when satellite data showed detectable SO2 emissions from the volcano in close conjunction with an increase in earthquake activity (Cameron and others, 2023).\"","StartYear":2021,"StartMonth":8,"StartDay":10,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2021,"EndMonth":8,"EndDay":27,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Atka volcanic complex","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak17","ParentVolcanoID":"ak17"},{"ID":4801,"Name":"Atka 2021 unrest","Description":"From Orr and others, 2024: \"Beginning on August 10, 2021, AVO detected a swarm of earthquakes at Atka volcanic complex that lasted several days before tapering off. In response to this local seismicity, AVO raised the Aviation Color Code and Volcano Alert Level to YELLOW and ADVISORY on August 11. \r\n\"AVO analysts located 204 earthquakes between August 10 and 12; these events had epicenters approximately 3-9 km [2-6 mi] west-southwest of Mount Kliuchef and typical depths of 2-5 km [1.2-3 mi] below sea level. The largest earthquake took place on August 11 and had an ML of 2.5. Five other earthquakes exceeded ML 2.0. The rate of earthquakes began to decline after August 12 and returned to background levels by the end of the month. In response, AVO changed the Aviation Color Code and Volcano Alert Level of Atka volcanic complex to GREEN and NORMAL on August 27. Satellite imagery and infrasound sensors detected no anomalous activity or unrest around the time of the earthquake swarm, in contrast with observations from October 2020, when satellite data showed detectable SO2 emissions from the volcano in close conjunction with an increase in earthquake activity (Cameron and others, 2023).\"","StartYear":2021,"StartMonth":8,"StartDay":10,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2021,"EndMonth":8,"EndDay":27,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Atka volcanic complex","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak17","ParentVolcanoID":"ak17"},{"ID":4868,"Name":"Novarupta ash resuspension 2021","Description":"From Orr and others, 2024: \"On August 28, 2021, strong winds picked up loose volcanic ash from the Mount Katmai (Novarupta) region and carried it southeastward toward Kodiak Island. The National Weather Service (NWS) had forecasted this event a few days prior, and when it occurred, the NWS Alaska Aviation Weather Unit (AAWU) reported cloud heights as much as ~6,000 ft (~1,800 m) ASL, issuing a significant meteorological information statement (SIGMET) for aviators. AVO also issued an Information Statement. \r\n\"The following month, strong winds again generated a cloud of resuspended ash that drifted over Kodiak Island. This event, like the one a month prior, was anticipated by the NWS a few days in advance. The drifting ash cloud appeared clearly in satellite data for ~24 hours, starting in the afternoon of September 20. AAWU issued a SIGMET reporting ash at altitudes as high as ~8,000 ft (~2,400 m) ASL; AVO correspondingly issued an Information Statement. Trace ash fall was reported in the City of Kodiak, Alaska, and owing to the forecast of this event, a local observer was able to sample the ash fall and send it to AVO.\r\n\"The ash resuspension had ceased for only two days when, beginning late in the afternoon on September 23, winds again picked up loose ash. This ash cloud drifted east across northern Kodiak Island at an apparently lower altitude (~5,000 ft [~1,500 m] ASL), though no ashfall was reported. This resuspension event also lasted ~24 hours, during which time AAWU issued a SIGMET and AVO issued an Information Statement. \r\n\"AVO observed the next minor cloud of resuspended ash in satellite views on September 26. This cloud drifted southeastward toward the middle of Shelikof Strait, never reaching Kodiak Island. No Information Statements were issued for this minor event. \r\n\"Before dawn on October 2, strong winds near Mount Katmai once again picked up loose volcanic ash and carried it southeastward toward Kodiak Island. As with most previous resuspension events at Mount Katmai in 2021, the NWS had forecasted the event a few days prior. AAWU issued a SIGMET and the NWS Forecast Office issued a Marine Weather Statement. AVO issued an Information Statement reporting ash clouds that reached altitudes of ~6,000 ft (~1,800 m) ASL. Meteorological clouds obscured satellite observations the next day, but the SIGMET remained in place for ~24 hours owing to the likelihood of continued ash resuspension. \r\n\"Starting on the morning of November 17, another cloud of resuspended ash appeared clearly in satellite data. Most of the typical source region for resuspended ash at Mount Katmai was covered in snow at the time, so this event’s ash source was apparently confined to valleys on the north side of Shelikof Strait, in the vicinity of Mount Katmai. AAWU issued a SIGMET reporting a cloud altitude as high as ~7,000 ft (~2,100 m) ASL; AVO correspondingly issued an Information Statement. Resuspended ash was visible in satellite data until about midnight, although reports of resuspended ash from the City of Kodiak continued into the following day. Residents in Kodiak collected trace ashfall. \r\n\"The last resuspension event in the Mount Katmai region in 2021 occurred on November 25. AAWU issued a SIGMET reporting a cloud that drifted over Kodiak Island at an altitude as high as ~5,000 ft (~1,500 m) ASL. The NWS Forecast Office issued a Marine Weather Statement and AVO issued an Information Statement.\"","StartYear":2021,"StartMonth":8,"StartDay":21,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2021,"EndMonth":11,"EndDay":25,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Novarupta","ParentVolcano":"Novarupta","VolcanoID":"ak203","ParentVolcanoID":"ak203"},{"ID":4811,"Name":"Davidof 2021 unrest","Description":"From Orr and others, 2024: \"On December 7, 2021, at 15:33 HAST (December 8 at 01:33 UTC), an earthquake swarm occurred 7.5 km north of Davidof volcano. During the first few days of the swarm, several energetic earthquake bursts took place, the largest of which was a ML 4.2 on December 10. The sudden increase in seismic activity was uncharacteristic of the area, prompting AVO to raise the Aviation Color Code and Volcano Alert Level from UNASSIGNED to YELLOW and ADVISORY on December 10 in anticipation of possible volcanic activity. \r\n\"Seismicity waned gradually over the next week and the swarm seemingly ceased on December 20. The hypocenters of earthquakes from the swarm formed a northeast-southwest trending lineation north of the volcano. However, this linear trend is interpreted to be an artifact because the earthquakes were located outside the regional network-the closest seismic stations are the four on Little Sitkin Island, ~12 km [~7 mi] east of Davidof volcano. The earthquakes occurred at a variety of depths, the deepest of which was 9.8 km [6.1 mi] below sea level. Notably, the swarm produced 2 earthquakes of ML \u003e4 and 13 earthquakes of ML \u003e3. On December 29, more than one week after the swarm ended, AVO lowered the Aviation Color Code and Volcano Alert Level of Davidof volcano to UNASSIGNED.\"\r\nAVO raised Davidof to YELLOW/ADVISORY again on January 26, 2022, stating \"over the past two days a swarm of earthquakes has occurred in the vicinity of Davidof volcano. The largest earthquake in the current sequence happened yesterday at 4:02 PM AKST (January 26, 01:02 UTC) and had a magnitude of 4.9. A similar earthquake swarm occurred in December 2021. No signs of unrest have been observed in recent satellite images of the volcano.\"\r\nElevated seismic activity continued for a few months, occasionally including earthquakes of ML = 3. Afterwards, seismicity gradually declined, and AVO lowered the alert levels to UNASSIGNED on April 22, 2022.","StartYear":2021,"StartMonth":12,"StartDay":7,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2022,"EndMonth":4,"EndDay":22,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Davidof","ParentVolcano":"Davidof","VolcanoID":"ak73","ParentVolcanoID":"ak73"},{"ID":4832,"Name":"Edgecumbe unrest 2018","Description":"AVO issued an Information Statement on April 13, 2022, for Mount Edgecumbe, stating \"A swarm of earthquakes has been detected in the vicinity of Mount Edgecumbe volcano, beginning at about 2 am AKDT on Monday, April 11, 2022. There have been hundreds of small quakes in the swarm, though the large majority are too small to locate. The National Earthquake Information Center reported that one of the largest earthquakes in the swarm occurred at 11:04 AKDT on April 11, with a magnitude of 2.8 at 10 km depth. The Alaska Earthquake Center reported another earthquake occurred at 3:44 pm AKDT on April 11, with a magnitude of 2.1 and depth of 4 km. As of this morning, the swarm continues, though the rate of earthquakes has declined over the past 24 hours.\r\n\"The cause of this earthquake swarm is currently unknown. This swarm may be associated with volcanic processes, regional tectonic activity, or a combination of sources. AVO does not have local seismic instruments in the area, and the closest station is in Sitka, 24 km (15 miles) to the east of the volcano.\r\n\"Retrospective analysis of earthquake data in the area shows that a small number of earthquakes started occurring under Edgecumbe in 2020. This week's activity is unusual in the number of events, however.\"\r\nAVO issued a following information statement on Friday, April 22, 2022, stating \"A swarm of earthquakes was detected in the vicinity of Mount Edgecumbe volcano beginning on Monday, April 11, 2022. There were hundreds of small quakes in the swarm, though the large majority were too small to locate. Over the past few days, earthquake activity has declined and is currently at background levels. \r\n\"The recent swarm inspired an in-depth analysis of the last 7.5 years of ground deformation detectable with radar satellite data. Analysis of these data from recent years reveals a broad area, about 17 km (10.5 miles) in diameter, of surface uplift centered about 2.5 km (1.5 miles) to the east of Mt Edgecumbe. This uplift began in August 2018 and has been continuing to the present at a rate of up to 8.7 cm/yr (3.4 in/yr) in the center of the deforming area. Deformation has been constant since 2018, and there has not been an increase with the recent earthquake activity. The total deformation since 2018 is about 27 cm (10.6 inches). A figure showing the deformation can be seen here: http://www.avo.alaska.edu/images/image.php?id=182216 \r\n\"Retrospective analysis of earthquake data in the area of Mount Edgecumbe shows that a small number of earthquakes started occurring under the volcano in 2020. The recent earthquake activity that started on April 11 was unusual in having a greater number of events, however. The earthquakes detected under the volcano since 2020 are all M3.0 or smaller. Note that only the largest of the earthquakes can be located by regional seismic networks; hundreds of very small additional events have been detected, but not located. A map showing earthquake locations in the area, including those occurring on regional faults, can be found here: http://www.avo.alaska.edu/images/image.php?id=182214 \r\n\"There have been no visual changes, surface temperature changes, or gas emissions observed. \r\n\"The coincidence of earthquakes and ground deformation in time and location suggests that these signals are likely due to the movement of magma beneath Mount Edgecumbe, as opposed to tectonic activity. Initial modeling of the deformation signal shows that it is consistent with an intrusion of new material (magma) at about 5 km (3.1 miles) below sea level. The earthquakes likely are caused by stresses in the crust due to this intrusion and the substantial uplift that it is causing. \r\n\"Intrusions of new magma under volcanoes do not always result in volcanic eruptions. The deformation and earthquake activity at Edgecumbe may cease with no eruption occurring. If the magma rises closer to the surface, this would lead to changes in the deformation pattern and an increase in earthquake activity. Therefore, it is very likely that if an eruption were to occur it would be preceded by additional signals that would allow advance warning. \r\n\"There is no local volcano monitoring network at Edgecumbe. The closest seismic station is in Sitka, 24 km (15 miles) to the east of the volcano and is operated by the National Tsunami Warning Center. Updated satellite radar observations become available on weekly timescales. \r\n\"AVO has begun plans to add to current monitoring capabilities, possibly by adding instruments closer to the volcano. In the meantime, we are monitoring Edgecumbe using existing regional seismic stations and satellite data.\"","StartYear":2022,"StartMonth":4,"StartDay":11,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Edgecumbe","ParentVolcano":"Edgecumbe","VolcanoID":"ak90","ParentVolcanoID":"ak90"},{"ID":4834,"Name":"Trident unrest 2022","Description":"On August 24, 2022, an earthquake swarm began beneath Trident volcano in the Katmai area. The first earthquakes were at deep levels in the crust, around 16 miles below sea level, but progressed upward to about 3 miles beneath the surface over the next five days. Dozens of magnitude 0.7 to 1.9 earthquakes happened each day over this time period, but the rate of earthquakes dropped off somewhat after the 28th. There were also a few periods of volcanic tremor and low-frequency earthquakes.\r\nOn September 14, 2022, AVO released an Information Statement about the earthquake activity at Trident, stating that no other signs of unrest had been observed and that the seismic activity was likely caused by movement of magma or magmatic fluids.\r\nAfter the earthquakes continued into the next month, AVO raised the alert levels to YELLOW/ADVISORY on September 29.\r\nOn October 19, 2022, citing that the rate of earthquakes had dropped and seismic tremor had not observed since September 30, 2022, AVO lowered the Aviation Color Code to GREEN and the Volcano Alert Level to NORMAL.\r\nOn November 20, there was a magnitude 4.6 quake – this was far larger than most of the quakes in the area.\r\nIn late 2022 into January 2023, the rate of earthquakes began to pick up again. There were also more earthquakes occurring under Mount Katmai to the east, and under Martin and Mageik volcanoes to the west, though the largest number of earthquakes continued to be beneath Trident, as well as periods of tremor.\r\nOn January 11, 2023, AVO released an information statement for Katmai, Trident, Martin, and Mageik volcanoes, noting this more elevated activity. \r\nOn February 22, 2023, AVO again raised the Aviation Color Code and Volcano Alert Level at Trident to YELLOW/WATCH, stating that earthquakes were continuing to occurr at about 10 per day. The notice also stated that because of the tremor observed beneath Trident and the initial swarm there, the unrest in the broader Katmai region was likely, though not certain, because of magma or magmatic fluid movement beneath Trident.\r\nIn May 2023, AVO began detecting a marked increase in low-frequency earthquakes—in addition to regular earthquakes—at shallow and deep levels in the region between Trident and Novarupta, which lies 3 miles to the northwest. These types of earthquakes often indicate the movement of magma or magmatic fluids within the Earth’s crust. The deep low-frequency earthquakes were often accompanied by longer-duration bursts of continuous tremor, indicating deep fluid movement.\r\nIn June, satellite radar data taken in newly snow-free conditions was compared to data taken in the fall, which showed that Trident Volcano had inflated slightly, with the ground uplifted by about 2 inches, especially on the southern flank.\r\nOn July 25, 2023, AVO released another Information Statement about this activity, noting that earthquakes also continued to occur around Mount Katmai and Martin and Mageik volcanoes, but AVO continued to believe this was likely a secondary effect of magma/magmatic fluid intrusion beneath Trident.\r\nAfter July, earthquake activity remained elevated, and deep low-frequency earthquakes and periods of tremor continued. In September AVO noted that there was an increase in the rate of earthquakes very deep in the crust (greater than 9 miles down), as well as some minor additional ground deformation.\r\nBeginning in early October rates of earthquake activity declined somewhat, especially deeper earthquakes. AVO noted that this might indicate a decline in magma/magmatic fluid activity beneath Trident.\r\nSeismicity remained slightly elevated in December.\r\nIn the first week of January, AVO noted that while earthquakes were still occurring, their rate was now approaching the typical or \"background\" state for the Katmai area. Due to this, AVO lowered the alert levels back to GREEN/NORMAL on January 10, 2024.","StartYear":2022,"StartMonth":9,"StartDay":24,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2024,"EndMonth":1,"EndDay":10,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Trident","ParentVolcano":"Trident","VolcanoID":"ak288","ParentVolcanoID":"ak288"},{"ID":4835,"Name":"Takawangha unrest 2023","Description":"On November 18, 2022, AVO raised the Aviation Color Code and Volcano Alert Level at Takawangha to YELLOW/ADIVSORY, citing \"The number of small earthquakes detected near Takawangha volcano has increased over the past few days and has intensified over the past 24 hours. The earthquakes, the largest with magnitudes between 2 and 3, have preliminary depths of about 2 to 4 miles (3 to 6 km) below sea level. This activity may be due to the movement of magma beneath the volcano.\" This seismicity marks a departure from background activity.\"\r\nOn March 9, 2023, AVO raised Takawangha to ORANGE/wATCH, stating \"Over the past 48 hours, earthquake activity near Takawangha volcano has been elevated and continues. This sustained activity indicates an increased potential for eruption at the volcano. Therefore AVO is raising the Aviation Color Code to ORANGE and the Volcano Alert Level to WATCH. Seismic activity is also elevated at Tanaga Volcano, which is about 8 km (5 mi) west of Takawangha on Tanaga Island. If an eruption were to occur, it is uncertain at this stage if it would come from Takawangha or Tanaga.\"","StartYear":2022,"StartMonth":11,"StartDay":18,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2023,"EndMonth":7,"EndDay":18,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Takawangha","ParentVolcano":"Takawangha","VolcanoID":"ak277","ParentVolcanoID":"ak277"},{"ID":4836,"Name":"Aniakchak unrest 2023","Description":"On February 22, 2023, AVO raised the Aviation Color Code and Volcano Alert Level at Aniakchak to YELLOW/ADVISORY, citing increased seismicity. \"The number of earthquakes beneath Aniakchak volcano has recently increased and shifted to shallower depths. Due to this increase in seismic activity to above-background levels, the Alaska Volcano Observatory is raising the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.  There have been no signs of unrest in other monitoring data. \r\nBackground seismicity at Aniakchak has mostly been characterized by deep (\u003e15 km or 9.3 miles), long-period events occurring at a rate of ~4 earthquakes per month. From October 2022 to present, the rate of earthquakes has been more elevated and characterized by shallower earthquakes at depths less than 9 km (5.6 miles) below sea level. The earthquake rate has further increased since January 31 with dozens of earthquakes detected per day, including a M3.7 earthquake on February 17. \r\nThere is no indication that an eruption of Aniakchak is imminent, or that one will occur. Increases in seismic activity have been detected previously at other similar volcanoes, with no subsequent eruptions. We expect additional shallow seismicity and other signs of unrest, such as gas emissions, elevated surface temperatures, and surface deformation to precede any future eruption, if one were to occur. Should activity increase, AVO will issue further notices.\"\r\nSeismic activity continued at similar rates for a few weeks, then began to slowly decline while remaining above background. However, radar data in March showed that the ground within the central caldera was rising. On April 13, an Information Statement was issued, stating that the earthquake activity and ground uplist suggested that magma was intruding below Aniakchak at 2 to 2.5 mi depth.\r\nUplift continued into June, though at a slower rate. Earthquake activity declined still further around mid-June, though station outages limited data. The outages were fixed in early July.\r\nIn late July, there was a small uptick in seismic activity. However, levels declined again the next week.\r\nIn late July to early August, radar data showed no continued uplift of the area.\r\nOn August 17, 2023, AVO lowered the color code and alert level to GREEN/NORMAL, stating that earthquake and deformation activity had returned to background levels.","StartYear":2023,"StartMonth":2,"StartDay":22,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2023,"EndMonth":8,"EndDay":17,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Aniakchak","ParentVolcano":"Aniakchak","VolcanoID":"ak14","ParentVolcanoID":"ak14"},{"ID":4837,"Name":"Tanaga unrest 2023","Description":"On Tuesday, March, 7, 2023, AVO elevated the Aviation Color Code and Volcano Alert Level at Tanaga to YELLOW/ADVISORY, stating \"earthquake activity beneath Tanaga Volcano began to increase slowly starting at about 1:30 pm AKST today. At roughly 8:45 pm AKST this evening,  the activity escalated with earthquakes occurring as often as 2 or 3 each minute. Initial locations of these earthquakes place them at shallow depths beneath the summit of Tanaga Volcano, and the largest of these earthquakes have magnitudes between 2 and 3.\"\r\nOn Thursday, March 9, 2023, AVO elevated Tanaga again to ORANGE/WATCH, stating \"Over the past 24 hours, earthquake activity near Tanaga Volcano has been elevated and continues. This sustained activity indicates an increased potential for eruption at the volcano.*** Seismic activity is also elevated at Takawangha volcano, which is about 8 km (5 mi) east of Tanaga on Tanaga Island. If an eruption were to occur, it is uncertain at this stage if it would come from Tanaga or Takawangha.\"","StartYear":2023,"StartMonth":3,"StartDay":7,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2023,"EndMonth":7,"EndDay":18,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Tanaga","ParentVolcano":"Tanaga","VolcanoID":"ak280","ParentVolcanoID":"ak280"},{"ID":4838,"Name":"Shishaldin 2023/07","Description":"On July 11, 2023, AVO raised the Aviation Color Code to YELLOW and the Alert Level to ADVISORY for Shishaldin Volcano, citing the following information:\r\nStrongly elevated surface temperatures at the summit of Shishaldin Volcano have been observed in satellite data over the past day. Intermittent tremor and low-frequency earthquakes over the past week have gradually become more regular and consistent in the past day. In response, the Alaska Volcano Observatory is raising the Aviation Color Code to YELLOW and the Alert Level to ADVISORY. These observations represent a departure from normal background activity at Shishaldin, but do not necessarily indicate that an eruption will occur.\r\nOn the following day, July 12, AVO raised the Aviation Color Code to ORANGE and the Alert Level to WATCH for Shishaldin, citing the following information:\r\nStrongly elevated surface temperatures continue to be observed at the summit of Shishaldin Volcano in satellite data. Incandescence at the summit was observed in web camera images from last night and sulfur dioxide was detected in satellite data over the past day. In addition, seismic tremor amplitudes have increased over the past day. Together, these observations suggest that lava is likely present within the summit crater of Shishaldin. \r\nOn Friday, July 14, two explosions at 1:09 and 7:10 am AKDT, producing ash clouds to 25,00-40,000 feet (9-12 km) asl. Plumes drifted SE across the Pacific for at least 250 mi. Volcanic mudflows were generated on volcano’s flanks, the largest on the north side. Gas detections suggest elevated SO2 in the ash plume. Several smaller explosions with ash clouds below 15,000 ft occurred around 10:30 am. The Color Code and Volcano Alert Level remained ORANGE/WATCH.\r\nOn the evening of Saturday July 15, the eruption intensified, and AVO raised the Aviation Color Code and Volcano Alert Level to RED/WARNING at 11:57 pm AKDT, stating \"The explosive eruption of Shishaldin Volcano is continuing. A continuous ash plume now extends over 80 mi (125 km) to the SSE from the volcano with an altitude of about 16,000 ft (4.9 km) above sea level. Seismicity has remained elevated for over 6 hours and frequent explosion signals are being detected at regional infrasound (pressure sensor) networks. Some explosions are sending ash plumes as high as 20,000 ft (6 km) above sea level.\"\r\nOvernight, the eruptive activity declined and AVO lowered the Color Code and Volcano Alert level to ORANGE/WARNING. The drifting ash cloud was still visible in satellite imagery about 350 nautical miles ESE from the volcano. The NWS estimated the cloud as under 16,000 ft asl.\r\nLava continued to erupt from the summit crater on July 16 and 17.\r\nTuesday July 18 saw a return to explosive activity, with a rapidly growing ash cloud observed starting at 7 am local time and drifting SSE. AVO raised the Aviation Color Code and Volcano Alert Level to RED/WARNING in response for approximately three and a half hours.\r\nOn Wednesday, July 19, seismic stations and webcams south of the volcano were brought back online, increasing the monitoring capabilities at Shishaldin.\r\nAnother episode of eruptive activity occurred over the following weekend, starting late Saturday, July 22. The Aviation Color Code and Volcano Alert Levels were raised to RED/WARNING at 11:43 PM after an ash plume was observed in satellite data. The plume reached altitudes of 37,000 ft asl and drifted to the northeast. Alert levels were returned to ORANGE/WATCH four and a half hours later.\r\nIn the early morning hours of Wednesday, July 26, a sustained period of increased eruptive activity began. A more low-level ash plume reached 15,000 ft asl by 3:51 AM and continued for many hours, along with significant explosions. The Aviation Color Code and Volcano Alert Levels remained at ORANGE/WATCH during this event.\r\nOn the Thursday of the week following, August 3, volcanic tremor increased into the evening and surface temperatures were strongly elevated. Explosions were detected overnight in infrasound and seismic data. An ash plume reaching up to 31,000 ft erupted starting in the early morning hours of August 4 and continued into the afternoon, declining about 2 PM local time. The Aviation Color Code and Volcano Alert Levels were raised to RED/WARNING at 10:17 AM local time August 4 and were returned to ORANGE/WATCH at 7:55 PM that night.\r\nOn Monday, August 15, Shishaldin erupted an ash plume beginning around 2 AM local time that reached about 36,000 ft and generated volcanic lightning. Ash continued to erupt to lower altitudes (~16,000 feet) into August 16. The Aviation Color Code and Volcano Alert Levels remained at ORANGE/WATCH during this event.\r\nOn Friday, August 25, seismic unrest ramped up in the early morning hours and the first pilot reports of ash were received at 11:22 AM. The Aviation Color Code and Volcano Alert Levels were raised to RED/WARNING at 12:17 PM, and the ash plume eventually reached up to 32,000 ft and extended up to 280 miles. Ash emissions continued into the night and the Aviation Color Code and Volcano Alert Levels were returned to ORANGE/WATCH at 12:28 AM on August 26.\r\nOn Tuesday, September 5, seismicity once again increased in the early morning hours, and an ash plume to 32,000 ft was erupted starting about 8:30 AM. Aviation Color Code and Volcano Alert Levels were raised to RED/WARNING at 8:42 AM local time. The ash altitude and emissions decreased about 11 AM, but still continued at lower altitudes until about 1:30 PM. The Aviation Color Code and Volcano Alert Levels were returned to ORANGE/WATCH at 12:46 PM local time.\r\nOn Thursday, September 14, seismicity began ramping up about 6 pm local time, but decreased again without major eruptive activity. However, seismicity increased again on Friday, September 15, and an explosive eruption began about 5:10 PM local time. The Aviation Color Code and Volcano Alert Levels were raised to RED/WARNING at 5:41 PM. The ash plume reached 42,000 ft and abundant volcanic lightning was observed. The ash plume detached from the volcano about 6:30 PM, but more ash erupted starting at 7:30 PM. Trace ash fall was reported in False Pass during this event. The Aviation Color Code and Volcano Alert Levels wee returned to ORANGE/WATCH at 12:44 AM Saturday, September 16, after seismicity returned to pre-event levels.\r\nOn Friday, September 22, seismicity began increasing throughout the day without major explosive activity. Lava erupted within the crater starting on September 24, accompanied by low-level ash emissions and flows down the mountain’s flanks. In the early morning hours of Monday, September 25, an ash plume erupted starting at about 5:45 AM local time, reaching 45,000 ft. The Aviation Color Code and Volcano Alert Levels were raised to RED/WARNING at 6:02 AM. The ash plume detached about 7 AM. Trace ash fall was reported in False Pass, King Cove, Cold Bay, and Sand Point. The Aviation Color Code and Volcano Alert Levels were returned to ORANGE/WATCH at 12:34 PM Monday.\r\nAfter the major event on September 25, seismic activity decreased, but several collapse events occurred in the crater area and steaming pyroclastic flow and lahar deposits were seen on the volcano’s flanks.\r\nOn Monday, October 2, seismicity began increasing in the evening starting around 9 PM local time. Lava fountaining and hot avalanches occurred during the night. A significant explosive eruption of Shishaldin started at 5:47 AM AKDT the following morning, October 3. The explosive eruption produced an initial ash cloud as high as 40,000 ft asl, with subsequent ash emissions to between 20,000 and 25,000 ft asl. The eruption was observed in satellite images, webcams, lightning, and seismic and infrasound data. The Aviation Color Code and Volcano Alert Levels were raised to RED/WARNING at 6:12 AM. Ash emissions continued for several hours, dropping down to about 20,000 to 25,000 ft asl. The Aviation Color Code and Volcano Alert Levels were returned to ORANGE/WATCH at 10:36 am October 3 after explosive activity ended, although steaming and small collapse events continued.\r\nAfter the event on October 3, seismic activity remained elevated for two weeks. Pyroclastic flow and lahar deposits were observed, along with explosion craters at their toe, as was evidence for more collapses of the crater rim. Shishaldin emitted increased levels of sulfur dioxide (SO2) during the weeks of October 9 and October 16. Seismicity and sulfur dioxide emissions began to decline the week of October 23.\r\nOn Tuesday, October 31, AVO changed the Aviation Color Code and Volcano Alert Levels to YELLOW/ADVISORY, citing the decrease in seismicity and sulfur dioxide emissions over the past week.\r\nTwo days later, on Thursday, November 2, volcanic tremor increased again. The Aviation Color Code and Volcano Alert Levels were raised back to ORANGE/WATCH at 8:31 PM AKDT that night, with AVO stating that an eruption was likely underway. Satellite images showed ash emissions started at about 8:00 PM local time. The emissions lasted until Friday morning, but as the ash plume didn’t exceed 20,000 ft above sea level, the Aviation Color Code and Volcano Alert Levels remained at ORANGE/WATCH during this event.\r\nAfter the explosive event on November 3, much smaller explosions and collapse events around the summit crater rim occurred frequently for about a week, along with above-background levels of seismicity, elevated surface temperatures, and steam and gas emissions. During the weeks following, the frequency of small explosions detected in infrasound data dropped off, and gas emissions and elevated surface temperatures were less frequently detected. Seismicity remained somewhat elevated, and steam plumes and collapse events were sometimes observed. There was a small cluster of earthquakes starting on December 25 about 4-6 miles southwest of Shishaldin's summit.\r\nOn January 2, AVO lowered the alert levels to YELLOW/ADVISORY, stating that activity had declined over the two months prior, and that there had not been any evidence of eruption-driven changes to the volcano outside of the crater or evidence of lava within the crater. However, unrest continued with the small events taking place deep in the vent.\r\nMinor steam emissions and seismicity (including occasional tremor) continued in January and February, but explosion signals dropped off. Steam emissions were observed on and off in webcam views.\r\nOn February 11, a minor ash plume was observed in a webcam view, prompting AVO to raise the alert levels to ORANGE/WATCH at 12:46 PM AKST. Analysis of seismic, infrasound, and thermal data indicated no evidence of explosive activity, which led AVO to conclude that this event was most likely caused by a small rockfall or debris flow. Therefore, the alert levels were returned to YELLOW/ADVISORY on February 17. Satellite data on February 17 and 19 showed that additional collapse events had occurred on the upper southeast and northeast flanks, but otherwise activity remained low.\r\nIn the latter part of February, Shishaldin was fairly quiet, with barely elevated seismicity and intermittent steaming.\r\nOn March 7, an SO2 plume was noted in satellite data. Through the end of April, roughly 1-2 SO2 observations per week were accompanied by some periods of seismic tremor, occasional gas-bubble burst signals noted in infrasound, occasional weakly elevated surface temperatures, and a robust steam/gas plume.\r\nOn May 10 through May 16, a few new areas of ash were spotted in webcam images of the snow-covered summit. These were likely caused by minor collapses of the inner crater wall that were observed in radar satellite data. Weak infrasound, occasional tremor, and steam plumes were also observed.\r\nBetween May 16 and June 7, volcanic earthquakes and occasional tremor were observed, along with steaming when the weather was clear. SO2 gas was observed on six days during this period.\r\nBetween June 7 and July 12, sulfur dioxide gas emissions were observed in satellite data several times each week, along with a fairly persistent steam plume, earthquakes, occasional tremor, and weak infrasound explosion signals when observation conditions were good.\r\nBetween July 12 and July 26, sulfur dioxide gas observations were less frequent, though other activity remained approximately the same.\r\nOver the week of August 2, an AVO field crew conducted fieldwork at Shishaldin, including helicopter overflights on July 28 and 30 and August 1. Thermal imaging revealed a warm central vent deep within the summit crater, and gas instruments detected sulfur dioxide within the persistent steam and gas plume.\r\nOver the month of August, the typical steam plume was observed during clear weather, along with small volcanic earthquakes and weak seismic tremor and infrasound signals.\r\nOn August 30, 2024, AVO returned the Aviation Color Code and Volcano Alert Level to GREEN and NORMAL. The accompanying statement specified that while seismicity was still slightly elevated and gas emissions and small infrasound signals continued at Shishaldin, these signals had declined over time since the last explosive event in November and were expected to persist for a good while longer in the post-eruptive period. In AVO’s opinion, the volcano no longer posed any immediate threat of eruptive activity, and any resumption of activity would be preceded by detectable signals.","StartYear":2023,"StartMonth":7,"StartDay":11,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2023,"EndMonth":11,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":4839,"Name":"Cleveland unrest 2023","Description":"On July 19, 2023, AVO raised the Aviation Color Code and Volcano Alert Level for Cleveland to YELLOW/ADVISORY, stating: \"There has been an increase in the number of earthquakes observed near Cleveland volcano over the past week. Numerous earthquakes have been detected and 37 of these were large enough to be located by the local seismic network. Most of the earthquakes from early in the week located in the mid to shallow portions of the Earth’s crust, less than 11 miles (18 km) below the surface, while more recent earthquakes have been located at shallower depths, less than 4 miles (6 km) below the surface. These earthquakes are small (less than magnitude 2), but the frequency of events is unusual for Cleveland. These data along with satellite observations of elevated surface temperatures at the summit crater and continued gas emissions suggest an increased likelihood of a future eruption. In response, the Alaska Volcano Observatory is increasing the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.\"\r\nOver the next week, seismicity continued at elevated levels, and steam as gas plumes and elevated surface temperatures were detected at Cleveland (though the latter two are very common even when seismicity is at background levels). Then seismicity gradually declined through mid-August, and on August 25, the alert levels were reduced to GREEN/NORMAL.","StartYear":2023,"StartMonth":7,"StartDay":19,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2023,"EndMonth":8,"EndDay":25,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":4842,"Name":"Bogoslof unrest 2023","Description":"On October 24, 2023, AVO raised the Aviation Color Code and Volcano Alert Level for Bogoslof to YELLOW/ADVISORY, stating:\r\n\"Over the past three days, over 90 earthquakes have been detected in the vicinity of Bogoslof volcano. This marks a change in behavior and the Aviation Color Code and Volcano Alert Level is being increased to YELLOW/ADVISORY. Increases in seismic activity typically precede eruptions, but many volcanoes have exhibited similar behavior that did not result in eruptions. There have been no other signs of unrest observed in satellite data over the past several days.\"\r\nSeismicity levels at Bogoslof gradually declined over the next month, and no other signs of unrest were observed. On November 24, 2024, AVO returned the alert levels to UNASSIGNED, stating that activity had returned to background levels.","StartYear":2023,"StartMonth":10,"StartDay":24,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2023,"EndMonth":11,"EndDay":24,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Bogoslof","ParentVolcano":"Bogoslof","VolcanoID":"ak29","ParentVolcanoID":"ak29"},{"ID":4843,"Name":"Kanaga 2023/12","Description":"On December 19, 2023, AVO raised the alert levels at Kanaga Volcano to YELLOW/ADVISORY, stating: \"A small explosion was detected at Kanaga Volcano overnight at 22:31 AKST Dec 18 (07:31 UTC Dec. 19), and AVO is increasing the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.  The event was detected in local infrasound and seismic data and was followed by elevated earthquake seismicity that is ongoing.  No ash emisions have been observed in partly cloudy satellite images.\"\r\nIncreased earthquake activity followed the explosion, and satellite imagery taken afterwards showed a debris flow extending 0.9 miles northwest of the summit crater rim, and a series of northwest-southeast oriented fractures both within the summit crater and extending down the southeast flank. Minor steaming was observed when the weather was clear.\r\nElevated seismic activity was ongoing until January 2, when seismic stations (and webcams) for Kanaga went offline due to a weather-related outage. Satellite images of the volcano were obscured by clouds until two weeks later, when a clear view showed no further changes at the surface.\r\nOn January 28, connection to the seismic stations and webcams was restored. Webcam views showed steaming at the summit, and a few earthquakes were detected daily during the first week afterward. A period of weak seismic tremor was observed on January 31.\r\nDuring February, earthquake rates dropped to a few per week.\r\nOn February 27, 2024, AVO lowered the alert levels to GREEN/NORMAL, stating that seismicity had decreased to background levels and satellite and webcam data showed no recent surface changes, elevated temperatures or gas emissions, though steaming was still sometimes present.","StartYear":2023,"StartMonth":12,"StartDay":18,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2024,"EndMonth":2,"EndDay":27,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kanaga","ParentVolcano":"Kanaga","VolcanoID":"ak144","ParentVolcanoID":"ak144"},{"ID":4861,"Name":"Gareloi unrest 2024","Description":"On February 12, 2024, at 1:10 PM AKST, AVO raised the alert levels at Gareloi to YELLOW/ADVISORY, stating: \"Over the past several hours, AVO has detected an increase in seismicity at Mount Gareloi (Gareloi volcano) beginning at 09:15 AKST (18:15 UTC). The current activity marks a change in character above background rates...There have been no other notable changes at the volcano in satellite data or webcam views. Mount Gareloi persistently emits magmatic gases from a fumarole field on the south crater and commonly exhibits low-level seismic activity. These observations suggest the presence of shallow magma and potential interaction with a hydrothermal system. The current increase in seismicity likely reflects a change to the magmatic-hydrothermal system, but it is not clear that the likelihood of a volcanic eruption has increased.\"\r\nIn the week afterward, seismicity remained elevated, with numerous earthquakes and volcanic tremor. In the following week, seismicity did decrease somewhat, while remaining somewhat above background levels. Steaming was frequently observed, but this is not abnormal at Gareloi.\r\nOn March 5, 2024, AVO returned the alert levels to GREEN/NORMAL, stating that seismicity had returned to background levels.","StartYear":2024,"StartMonth":2,"StartDay":12,"StartTime":"22:10:00","StartQualifier":null,"StartQualifierUnit":null,"EndYear":2024,"EndMonth":3,"EndDay":5,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Gareloi","ParentVolcano":"Gareloi","VolcanoID":"ak106","ParentVolcanoID":"ak106"},{"ID":4862,"Name":"Korovin 2024","Description":"On March 28, 2024, AVO raised the alert levels at the Atka volcanic complex to YELLOW/ADVISORY, stating: \"A small, short-lived explosion was detected at the Atka volcanic complex this evening at 19:36 AKDT March 27 (03:36 UTC March 28), and AVO is increasing the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.  The event was detected in local infrasound and seismic data and was followed by a few minutes of elevated seismic tremor. Processing of the local infrasound data indicates the explosion originated from the summit crater of Korovin, one of several volcanoes within the Atka volcanic complex. No ash emissions have been observed in satellite images.\"\r\nFor a few days afterwards, seismic activity continued above background levels. There were low-frequency earthquakes and periods of seismic tremor.\r\nBy April 9th, seismicity had returned to background levels. Therefore, AVO returned the alert levels to GREEN/NORMAL on that day.","StartYear":2024,"StartMonth":3,"StartDay":28,"StartTime":"03:36:00","StartQualifier":null,"StartQualifierUnit":null,"EndYear":2024,"EndMonth":4,"EndDay":9,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Korovin","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak171","ParentVolcanoID":"ak17"},{"ID":4864,"Name":"Cleveland unrest 2024","Description":"On July 5, 2024, AVO raised the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY for Cleveland volcano, citing sulfur dioxide gas emissions were detected on local gas monitoring sensors at Mount Cleveland starting June 21 with an increase in emission rate June 24-30. Although sulfur dioxide emissions declined to background levels on July 1, moderately elevated surface temperatures and vigorous steaming at the summit of the volcano observed over the past couple of days,\r\nOn July 8, 2024, the alert levels were returned to GREEN/NORMAL. While sulfur dioxide emissions continued to be observed, but at a level typical of background or usual activity.","StartYear":2024,"StartMonth":7,"StartDay":5,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":2024,"EndMonth":7,"EndDay":8,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Cleveland","ParentVolcano":"Cleveland","VolcanoID":"ak52","ParentVolcanoID":"ak52"},{"ID":4869,"Name":"Spurr unrest 2024","Description":"On October 16, 2024, AVO raised the color code and alert level to YELLOW/ADVISORY, stating: \"AVO has observed a gradual increase in volcanic unrest over a period of several months at Mount Spurr, located about 120 km (75 miles) west of Anchorage (https://avo.alaska.edu/image/view/196123). GNSS receivers have detected sustained upward and outward ground deformation since March 2024. An increase in seismic activity has also been noted since April (https://avo.alaska.edu/image/view/196122). Other indications of elevated activity include the development of a small lake in the summit crater in early summer of 2024.\r\n\"The largest magnitude earthquake detected in this current period of unrest is a M2.3 earthquake on October 6th. This increase in activity was described in detail in an Information Statement (https://avo.alaska.edu/news/hans/DOI-USGS-AVO-2024-10-09T19:43:26+00:00) that AVO released on October 9th. Analysis of seismic data indicates a subtle increase in the rate and size of earthquakes over the past few weeks. Because this is a notable departure from the normal background seismicity of the volcano, AVO is raising the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY. However, there are no indications that an eruption is imminent. Often this type of seismicity and ground deformation will decline without producing an eruption.\r\n\"AVO continues to closely monitor activity at Mount Spurr for signals that would indicate that the volcano is moving closer to an eruption. Based on previous eruptions, changes from current activity in the earthquakes, ground deformation, summit lake, and fumaroles would be expected if magma began to move closer to the surface. Therefore, it is very likely that if an eruption were to occur it would be preceded by additional signals that would allow advance warning. \"\r\nOver the following two weeks, there were more than 180 small earthquakes at Mount Spurr. Over the week of November 1st, there were also a few episodes of possible volcanic tremor, which might indicate deep fluid movement. No unusual activity or surface changes were observed in satellite data or webcam views. AVO staff visited on October 24th to conduct pre-winter maintenance on Spurr’s monitoring network and noted that the fumaroles (steam/gas vents) in Spurr summit’s crater were steaming.\r\nOver the following weeks, earthquakes continued at varying rates, as is typical during periods of unrest. Steam was occasionally visible rising from Spurr’s summit during clear weather. On December 10, there was a M2.8 earthquake beneath the summit, and a few more episodes of tremor were recorded that week. \r\nOn Wednesday, December 18, AVO staff conducted a gas flight at Mount Spurr. Measurements of H2O, SO2, H2S, and CO2 were collected. Results were similar to the previous gas flight conducted on June 23, 2024. Personnel also took images and video during the flight that allowed accurate measurements of the crater lake that formed this year, showing that it has grown considerably since June despite the transition into winter. No activity was observed at Crater Peak.\r\nAs the new year turned, there were some notable periods of increased earthquake activity within the context of the larger unrest episode. The week of January 3, 2025, over 260 earthquakes were located, the largest being an M2.9 on January 2. Meanwhile, GPS data continued to show slow, steady inflation of the ground surface. Satellite radar data the week of January 10 showed that the crevasses in the summit crater were widening, demonstrating continued heat input to the area.\r\nDuring late January, the monitoring network at Mount Spurr experienced some issues transmitting data back to AVO due to poor weather, not unusual for this time of year.\r\nOn January 31, AVO reported that over the past few weeks more of the ongoing earthquakes had clustered under Crater Peak, the vent that produced the 1953 and 1992 eruptions. \r\nOn February 6, AVO released an Information Statement detailing the activity since the color code change in October. The statement noted that over 2700 earthquakes had been detected to date during the period of unrest, which as of this date was ten months long. Movement of the ground surface near the area of Spurr was now about 2.4 inches total, as measured at the closest monitoring station to the mountain. Based on the earthquakes, deformation, growth of the lake in the Spurr summit crater, and low levels of volcanic gases measured, AVO rated the odds of no eruption and a future eruption at the Crater Peak vent as equally likely, with an eruption from Spurr summit less likely. However, additional signs of unrest would be expected in the lead up to an eruption.\r\nOn February 7, AVO staff visited the Spurr monitoring network to clear snow and ice from the instruments. They also collected additional volcanic gas measurements which showed no significant changes since the previous gas flight in December.\r\nThe remaining weeks of February followed the same general trends, with earthquake rates varying quite a bit while other signs of unrest-deformation and occasional steaming from the summit-remaining consistent. Fewer earthquakes were located close to Crater Peak.\r\nOn March 7 and March 11, AVO conducted flights to once again measure any volcanic gases emitted by Spurr. These flights, while consistent with one another, yielded considerably altered results from the previous flights. Elevated levels of sulfur dioxide and carbon dioxide were measured at Spurr summit, while very high levels of carbon dioxide were measured at Crater Peak. Staff also observed newly reactivated fumaroles within Crater Peak. These new changes led AVO to release an Information Statement on March 12 stating that likelihood of an eruption had increased and that AVO considered an eruption similar to 1953 and 1992 at Crater Peak to be the most likely outcome of the current unrest episode.\r\nOn March 17, AVO staff visited the Spurr monitoring network to conduct maintenance and clear the snow and ice from the CKT webcam. A new webcamera (SPCR cam) was installed at the same station on a tall mast to permanently resolve the problem with snow burial of the CKT cam, though the new feed took a few days to become available.\r\nOn March 21, another gas measurement flight occurred. Results were similar to the flights on March 7 and 11.\r\nIn the latter half of March and first part of April, earthquake rates decreased somewhat relative to early in the month. Ground deformation also slowed. However, occasional steam plumes were still visible originating at the summit. A long period of poor weather prevented gas measurement flights and limited satellite and webcam observations.\r\nOn April 17, AVO released another information statement stating that due to decreasing earthquake and deformation rates relative to early March, AVO believed that the chance of an eruption had decreased somewhat, though one was still possible. The availability of a new livestreaming camera viewing Spurr from Anchorage was also announced.\r\nOn April 23, an AVO field crew conducted maintenance on the Spurr monitoring network, but wind conditions were not suitable for gas measurements. On April 24 a repeat flight was able to take gas measurements, with results once again similar to the three gas flights in March.\r\nDuring the second half of April, earthquake rates remained lower than in early March, though still above background, and deformation remained slower as well.\r\nThe rate of earthquakes and pause in deformation continued into early May. During the week of May 16, another monitoring network maintenance trip was performed, but conditions did not allow for gas measurements. During that week, earthquake numbers increased slightly, and they continued to increase for the week following as well, though rates still remained below the peak in early 2025. Sulfur dioxide emissions were more regularly observed in satellite data, and vapor plumes from Spurr summit were visible during good weather.\r\nOn May 23, AVO was able to conduct another gas measurement flight. Results were roughly similar to those in late April. The field crew observed steaming and degassing at fumaroles in both the Spurr summit crater and within Crater Peak, which was consistent with other recent field observations.\r\nIn the May 30 weekly update, AVO included a statement that said the magma intrusion driving the unrest at Spurr had most likely stalled, as demonstrated by the reduced deformation rates and declining seismicity.\r\nDuring the month of June, earthquake rates continued to be lower than in early 2025. For the first three weeks of June, slightly over 40 earthquakes were located each week. In the last week of June, that number declined to just 17. On June 11, another gas measurement flight found similar results to the previous one on May 23. On June 19, AVO staff installed a semi-permanent gas monitor on the rim of Crater Peak, which returned consistent measurements with the gas measurement flights when the wind direction allowed. Staff also installed a second livestream camera in June close to Spurr at station SPCL.\r\nThings continued much the same in July, with modest earthquake activity, occasional observations of gas emissions when conditions allowed, and no sign of continuing deformation. On July 29, AVO released another Information Statement, which summarized the gradually decreasing unrest and how chances of an eruption had also decreased.\r\nIn August, earthquake numbers continued to decline, ground deformation remained paused, and steaming remained minor. Gas emissions were still present, but decreased. On August 20, 2025, AVO lowered the Volcano Alert Level to NORMAL and the Aviation Color Code to GREEN, stating:\r\n“Over the past several months, signs of volcanic unrest at Mount Spurr—including small earthquakes, gas emissions, melting ice, and surface changes—have been gradually decreasing. No ground deformation has been detected since March 2025. Taken together, this means that the movement of magma toward the surface, which began in early 2024, has stopped. As a result, the chances of an eruption in the near-term are now considered extremely low.\r\n“Because of this, the Alaska Volcano Observatory (AVO) is lowering the Aviation Color Code to GREEN and the Volcano Alert Level to NORMAL, indicating that the volcano is currently quiet.\r\n“Small earthquakes are still occurring more frequently than before the unrest began in February 2024, and volcanic gases are still being released from the summit crater and the Crater Peak vent on the south flank of the volcano. This is normal for volcanoes where magma has moved upward but has not erupted. Minor gas emissions and a slightly higher number of small earthquakes could persist for many months to several years. \r\n“Although the potential for an eruption occurring in the near-term has passed, the volcano poses hazards for recreators on Mount Spurr. High levels of carbon dioxide gas detected on the rim of Crater Peak suggest that hazardous amounts of this odorless and colorless gas may be present within the crater, but not in local communities.\"","StartYear":2024,"StartMonth":10,"StartDay":16,"StartTime":"21:07:00","StartQualifier":null,"StartQualifierUnit":null,"EndYear":2025,"EndMonth":8,"EndDay":20,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Spurr","ParentVolcano":"Spurr","VolcanoID":"ak260","ParentVolcanoID":"ak260"},{"ID":4871,"Name":"Atka volcanic complex 2025","Description":"On February 20, 2025, AVO raised the color code/alert level at Atka to ORANGE/WATCH, stating:\r\n\"A single, small explosive event was detected in local seismic and infrasound data at 4:26 UTC (7:26 pm AKST) at the Atka volcanic complex. As a result, the Aviation Color Code and Alert Level has been changed to ORANGE/WATCH. The explosive event was short in duration (less than 10 seconds), and it is likely that a small amount of volcanic ash was erupted during this event. A meteorological cloud deck at an altitude of 8,000 to 10,000 ft above sea level obscured direct satellite observations, but no ash emissions were observed above the clouds. There have been no further explosive events observed and no noticeable change in seismic activity.\"\r\nOn February 21, 2025, AVO lowered the color code/alert level to YELLOW/ADVISORY, stating: \"There has been no further activity detected at the Aka volcanic complex since the small explosive event from 4:26 UTC on February 21 (7:26 pm on 2/20/25 AKST), and seismicity remains low. Thus, the Aviation Color Code and Alert Level are being reduced to YELLOW/ADVISORY. \r\n\"Further analysis of geophysical data confirms the source of the explosion as the summit lake region of Korovin Volcano and satellite data from last evening show no evidence of hot material at the surface. Our interpretation is that this was a steam-driven explosion, caused by overpressure of the subsurface cap beneath the lake. This type of singular explosion is common at Korovin Volcano. Minor amounts of ash were likely erupted in the immediate vicinity of the vent but have not been confirmed. Additional explosions are possible in the near future, but unlikely.\"\r\nOn March 3, 2025, AVO lowered the color code/alert level back to GREEN/NORMAL, stating: \"There has been no further explosive activity detected at the Atka volcanic complex since the small explosive event at 4:26 UTC on February 21 (7:26 pm on 2/20/25 AKST). Since then, seismicity has remained low. Thus, the Aviation Color Code and Alert Level are being reduced to GREEN/NORMAL.\"","StartYear":2025,"StartMonth":2,"StartDay":21,"StartTime":"04:26:00","StartQualifier":null,"StartQualifierUnit":null,"EndYear":2025,"EndMonth":3,"EndDay":3,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Atka volcanic complex","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak17","ParentVolcanoID":"ak17"},{"ID":4872,"Name":"Atka volcanic complex 2025/4","Description":"On April 25, 2025, the Alaska Volcano Observatory raised the alert level/color code to YELLOW/ADVISORY, stating: \"A small, short-lived explosion was detected at the Atka volcanic complex this morning at 10:34 AKDT April 25 (18:34 UTC April 25) in local infrasound and seismic data. Processing of the local infrasound data indicates the explosion originated from the summit crater of Korovin, one of several volcanoes within the Atka volcanic complex. AVO is increasing the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.\r\n\"High clouds blocked the area at the time of the explosion, preventing satellite observations. Similar past events at the Atka volcanic complex did not result in a noticeable ashfall or ash cloud or other impacts.”\r\nOn May 5, 2025, AVO returned the alert level and color code to GREEN and NORMAL, stating: \"No further explosive activity has been detected at the Atka volcanic complex since the small explosive event at 10:34 AKDT on April 25 (18:34 UTC on April 25). Thus, the Aviation Color Code and Alert Level are being reduced to GREEN/NORMAL.\r\n\"Brief explosive events at Korovin Volcano can occur without significant precursory unrest. Fallout of ash is unlikely to extend much beyond the upper flanks of the volcano. Possible ash clouds generated by such events are expected to be small and dissipate quickly.\"","StartYear":2025,"StartMonth":4,"StartDay":25,"StartTime":"18:34:00","StartQualifier":null,"StartQualifierUnit":null,"EndYear":2025,"EndMonth":5,"EndDay":5,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Atka volcanic complex","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak17","ParentVolcanoID":"ak17"},{"ID":4873,"Name":"Shishaldin unrest 2025","Description":"On August 25, 2025, AVO raised the Aviation Color Code and Volcano Alert Level to YELLOW/ADVISORY, stating:\r\n\"Over the past month, signs of volcanic unrest at Shishaldin Volcano have been gradually increasing. Sulfur dioxide emissions have increased, a more vigorous vapor plume from the summit crater has been observed, and seismic and infrasound data have shown moderate increases in both the number of events and their amplitude.  \r\n\"These observations represent a departure from background behavior and the Aviation Color Code and Volcano Alert Level are thus being increased to YELLOW/ADVISORY. \r\n\"An eruption is not certain, and this unrest could eventually decline over time. In the lead up to prior eruptions of Shishaldin, heat emissions were observed in satellite data as magma approached the floor of the summit crater. We have not detected elevated surface temperatures in the summit crater or observed anything else of significance, including during helicopter overflights by an AVO field crew on August 17 and 22, to indicate that magma is rising in the conduit.   \r\n\"Eruptions at Shishaldin are sometimes preceeded by days to weeks of seismic tremor (continuous shaking of the ground) that would provide warning of a possible explosive eruption.  \r\n\"Gas emissions from the summit crater have at times been mistaken by observers for ash emissions under certain viewing conditions (location of the sun relative to the observer), but there is no evidence for ash deposits on the snow around the summit crater in high resolution satellite data.  The absense of ash deposits was confirmed by the close overflight observations of the summit crater made last week by an AVO field crew.\"\r\nOver the following weeks, Shishaldin continued to experience relatively high rates of volcanic earthquakes. Infrasound signals and steaming were observed when weather conditions permitted. Sulfur dioxide emissions were seen regularly in satellite data.\r\nOver November and December, frequency of definitive satellite SO2 detections decreased (these detections are dependent on sufficient UV illumination). Other signs of unrest continued approximately the same as in previous months. There was a particularly impressive steam plume on November 27, prompting several passing pilots to submit pilot reports. The week of December 19, very strong winds caused resuspension of loose volcanic ash from previous eruptions at Shishaldin, as well as the other peaks on Unimak Island.\r\nDuring the first half of January, slightly elevated surface temperatures were observed at the summit crater several times in satellite imagery when clear weather occurred overnight.","StartYear":2025,"StartMonth":8,"StartDay":25,"StartTime":"19:48:00","StartQualifier":1,"StartQualifierUnit":"Months","EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Shishaldin","ParentVolcano":"Shishaldin","VolcanoID":"ak252","ParentVolcanoID":"ak252"},{"ID":4874,"Name":"Atka volcanic complex 2025/10","Description":"On October 29, 2025, the Alaska Volcano Observatory raised the Volcanic Alert Level and Aviation Color Code at Atka volcanic complex to ADVISORY/YELLOW, stating: \"A small explosion from Korovin Volcano was detected in seismic and infrasound data at 9:27 pm AKDT this evening, October 29, 2025 (5:27 UTC October 30, 2025).  The Aviation Color Code and Alert Level are being raised to YELLOW/ADVISORY.  Brief explosive events at Korovin Volcano can occur without significant precursory unrest. Fallout of ash is unlikely to extend much beyond the upper flanks of the volcano. Possible ash clouds generated by such events are expected to be small and dissipate quickly.\"\r\nOn November 4, 2025, AVO returned the Volcanic Alert Level and Aviation Color Code to NORMAL and GREEN, stating: \"No volcanic activity has been detected at the Atka volcanic complex since the small explosion at 21:27 AKDT on October 29, 2025 (05:27 UTC October 30, 2025).\"","StartYear":2025,"StartMonth":10,"StartDay":30,"StartTime":"05:27:00","StartQualifier":null,"StartQualifierUnit":null,"EndYear":2025,"EndMonth":11,"EndDay":4,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Atka volcanic complex","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak17","ParentVolcanoID":"ak17"},{"ID":4875,"Name":"Pavlof unrest 2026","Description":"On Jan 14, 2026 at 11:03 AM AKST, AVO raised the Aviation Color Code and Alert Level to YELLOW/ADVISORY, stating: \"The rate of long-period earthquakes has increased at Pavlof Volcano since approximately 12:45 am AKST (09:45 UTC) on January 14. No eruptive activity or emissions from the summit have been observed including in clear webcam images from this morning. The earthquake activity represents an increase from background levels, therefore the Alaska Volcano Observatory is raising the Aviation Color Code and Alert Level to YELLOW/ADVISORY. This type of earthquake activity in the past has preceded eruptions, but also has ended without an eruption occurring. We will continue to closely monitor the volcano for signs of increased activity, as eruptions at Pavlof Volcano often occur suddenly with little or no warning.\r\n\"The last eruption at Pavlof Volcano occurred in 2021 and 2022, and consisted of small lava flows and low-level explosions primarily from a vent on the upper southeast flank. Larger ash-producing eruptions last occurred at Pavlof in 2013, 2014, and 2016 from a crater on the upper north flank.\r\n\"Pavlof Volcano is monitored by local seismic and infrasound sensors, satellite data, web cameras, and regional infrasound and lightning networks. To view monitoring data and other information about Pavlof: https://avo.alaska.edu/volcano/pavlof.\"","StartYear":2026,"StartMonth":1,"StartDay":14,"StartTime":"09:45:00","StartQualifier":null,"StartQualifierUnit":null,"EndYear":2026,"EndMonth":1,"EndDay":21,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Pavlof","ParentVolcano":"Pavlof","VolcanoID":"ak210","ParentVolcanoID":"ak210"},{"ID":4877,"Name":null,"Description":"On May 12, 2026, citing increased seismic and gas activity at Kupreanof volcano, AVO raised the Aviation Color Code and Volcano Alert Level at Kupreanof volcano from UNASSIGNED to YELLOW/ADVISORY.\r\n\r\nFrom the May 12, 2026 Volcano Activity Notice: \"Seismic activity and volcanic gas emissions increased over the past few months and now continue at elevated levels at Mount Kupreanof. This activity is likely caused by a magmatic intrusion beneath the volcano. The Alaska Volcano Observatory (AVO) is therefore increasing the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY in response to this sustained volcanic unrest. \r\n\r\n\"Summary of activity and hazards \r\nSeismicity was first detected in February 2026 and has increased in recent months, with earthquakes as large as magnitude 3.1 detected. \r\nSulfur dioxide (SO2) emissions were detected beginning on April 4 with emission rates of ~100 to 1,000 tons per day, which are well above the background rate of \u003c100 tons per day. \r\nThese signals likely indicate a magmatic intrusion beneath Mount Kupreanof. \r\nAVO is therefore increasing the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY in response to this sustained volcanic unrest. \r\nData do not suggest an eruption is imminent and further signs of increased unrest would be expected prior to eruption. \r\nThere is no local monitoring network at Mount Kupreanof. Seismicity is detected using only regional stations, which limits detection of smaller events (magnitudes \u003c2) and results in large location errors.\"","StartYear":2026,"StartMonth":2,"StartDay":null,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Kupreanof","ParentVolcano":"Kupreanof","VolcanoID":"ak175","ParentVolcanoID":"ak175"},{"ID":4876,"Name":"Atka unrest 2026","Description":"On March 14, 2025, the Alaska Volcano Observatory raised the Aviation Color Code and Volcano Alert Level at Atka Volcanic Complex from GREEN/NORMAL to YELLOW/ADVISORY, citing a substantial increase in seismicity detected between 4;20 - 4;:30 pm AKST. AVO noted that small earthquakes and weak tremor were observed over the past week and elevated levels of sulfur dioxide gas were detected in satellite data. This activity increases the likelihood of explosive events at one of the volcanoes within the Atka volcano complex, most likely Korovin.","StartYear":2026,"StartMonth":3,"StartDay":20,"StartTime":null,"StartQualifier":null,"StartQualifierUnit":null,"EndYear":null,"EndMonth":null,"EndDay":null,"EndTime":null,"EndQualifier":null,"EndQualifierUnit":null,"Volcano":"Atka volcanic complex","ParentVolcano":"Atka volcanic complex","VolcanoID":"ak17","ParentVolcanoID":"ak17"}]