Alaskan Volcanoes

This information is from The Alaska Volcano Observatory (AVO). AVO is a joint program of the United States Geological Survey (USGS), the Geophysical Institute of the University of Alaska Fairbanks (UAFGI), and the State of Alaska Division of Geological and Geophysical Surveys (ADGGS). AVO was formed in 1988, and uses federal, state, and university resources to monitor and study Alaska’s hazardous volcanoes, to predict and record eruptive activity, and to mitigate volcanic hazards to life and property.

How many volcanoes in Alaska?

Alaska contains over 130 volcanoes and volcanic fields which have been active within the last two million years. These volcanoes are catalogued here.

Of these volcanoes, about 90 have been active within the last 10,000 years (and might be expected to erupt again), and more than 50 have been active within historical time (since about 1760, for Alaska). The volcanoes in Alaska make up well over three-quarters of U.S. volcanoes that have erupted in the last two hundred years.

Alaska’s volcanoes are potentially hazardous to passenger and freight aircraft as jet engines sometimes fail after ingesting volcanic ash. On December 15, 1989, a Boeing 747 flying 240 kilometers (150 miles) northeast of Anchorage encountered an ash cloud erupted from Redoubt Volcano and lost power in all four jet engines. The plane, with 231 passengers aboard, lost more than 3,000 meters (~9,800 feet) of elevation before the flight crew was able to restart the engines (Casadevall, 1994). After landing, it was determined the airplane had suffered about $80 million in damage (Brantley, 1990).

 

Volcanoes Monitored by AVO
Volcanoes Monitored by AVO

 

Where are Alaskan volcanoes located?

Most of Alaska’s volcanoes are located along the 2,500- kilometer-long (1,550-mile-long) Aleutian Arc, which extends westward to Kamchatka and forms the northern portion of the Pacific “ring of fire” (interactive map). Other volcanoes that have been active in the last few thousand years exist in southeastern Alaska (such as Edgecumbe) and in the Wrangell Mountains. Smaller volcanoes, some active within the last 10,000 years, are found in interior Alaska and in western Alaska as far north as the Seward Peninsula.

Alaskan Volcanoes Quick Reference Guide

Akutan

From Miller and others (1998): “Akutan volcano is a composite stratovolcano with a circular summit caldera about 2 km across and 60 to 365 m deep (Byers and Barth, 1953; Romick and others, 1990; Motyka and others, 1981) and an active intracaldera cinder cone. The caldera rim reaches a maximum altitude of 1303 m at Akutan Peak, the remnant of a pre-caldera cone now filled with a lava plug. The caldera is breached to the north. Caldera subsidence accompanied or followed eruptions from a series of rim vents. 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.

Amak

From Wood and Kienle (1990): “Amak is a small (~1 cubic km), young volcano in the Bering Sea some 50 km north of Frosty Peak volcano at Cold Bay at the western tip of the Alaska Peninsula. It is unusual in its position, which is significantly north of the main Aleutian volcanic front; Bogoslof, some 250 km west, is the only other such Aleutian volcano. In overall character, Amak is much like a large volcanic dome except that it has a well-formed crater from which granular, blocky leveed flows have erupted in historic times. The earlier volcanism, perhaps some 4,000-5,000 yr ago, consisted mostly of thin (~3 m) platy to massive andesite. U-shaped valleys in the older series of flows indicate significant glaciation during the latest ice phase some 6,700 yr BP. The southern margin of Amak is a grassy, apparently wave-cut alluvial plain, which contains a flat-bottomed crater with a distinct upturned rim, which may be a maar. Amak lavas are similar in overall composition to those of the Cold Bay volcanic center except in a small but significant higher concentration of potash in Amak rocks.”

Amukta

From Miller and others (1998): “The undissected stratovolcano of Amukta volcano composes most of nearly circular, 7.7-km-wide Amukta Island. The cone, about 5.8 km in basal diameter and topped by a 0.4 km wide summit crater, appears on synthetic-aperture radar imagery to be built on a 300+ meter high, east-west trending arcuate ridge. Extensions of that ridge on the southwest and east sides of the island indicate an older caldera approximately 6 km in diameter and open to the sea on the south side. No hot springs or fumaroles have been reported from Amukta. Sekora (1973, p. 29) reports the presence of a cinder cone near the northeastern shore of the island.”

Aniakchak

From Miller and others (1998): “Aniakchak Crater is an ice-free, circular caldera about 10 km in diameter and a maximum of 1 km deep which was first described by Smith (1925). The pre-caldera cone was built upon a basement of Tertiary sedimentary and volcanic rocks and Jurassic-Cretaceous sedimentary rocks, which are exposed high on the east and south walls of the caldera (Detterman and others, 1981). The elevation of the caldera rim varies from 1,341 m to 610 m. Surprise Lake, a 3.2-km-long lake in the northeast part of the caldera at an elevation of about 335 m is the source of the Aniakchak River, which flows through a breach in the eastern wall of the caldera. Numerous domes, flows, and cones occupy the interior of the caldera (Neal and others, 1992); the largest cone is Vent Mountain, 2.5 km in diameter and rising 430 m above the floor of the caldera. The pre-caldera cone was built on the west side of a basement high. The cone was deeply dissected by numerous glaciers that cut U-shaped valleys into the slopes before the caldera-forming eruption.

Atka

From Wood and Kienle (1990): “Atka is the largest (~200 cubic km) volcanic center in the central Aleutians. There are no larger centers westward, and the closest larger center is Umnak, some 300 km east. Seguam lies directly to the east, and Great Sitkin to the west. The overall structure of the center is that of a broad central shield which once supported a large (~2,200 m) center cone (Atka volcano) ringed by as many as 7 or 8 smaller satellite volcanoes. The central cone was lost to caldera formation, shutting down the whole system, and the satellite vents still remain at various stages of erosional decay. Sarichef is perhaps the youngest satellite vent and has survived erosion largely unscathed. More often, summit ice buildup has breached the crater walls, forming active cirques, which have deeply incised the satellite vents. Tangential to these vents are U-shaped valleys, formed by moving ice.

Augustine

From Miller et al (1998): “Augustine Island, an 8 by 11 km island in lower Cook Inlet, is composed almost entirely of the deposits of Augustine Volcano. Jurassic and Cretaceous sedimentary strata form a bench on the south side of the island and are overlain by granitoid glacial erratics and volcanic hyaloclastites. The volcano consists of a central dome and lava flow complex, surrounded by pyroclastic debris. The irregular coastline of Augustine Island is due to the repeated catastrophic collapse of the summit dome, forming debris avalanches down the flanks and into Cook Inlet. At least 11 avalanches have occurred in the past 2000 years with an average recurrence interval of about 150-200 years (Beget and Kienle, 1992; Beget, 1986).

Bogoslof

From Miller and others (1998): “Bogoslof Island is the largest of a cluster of small, low lying islands that comprise the emergent summit of a large submarine stratovolcano that rises more than 1500 m above the Bering Sea floor (Byers, 1959, plate 39). The volcano appears to be a back-arc feature as it occurs well behind the volcanic front of the main Aleutian arc. The island has undergone dramatic changes in size and shape during historical time, an evolution that has been unusually well observed and recorded for such an isolated volcano.

Carlisle

From Miller and others (1998): “Carlisle Island consists of a single symmetric cone, 1524 m high and 6.5 km in diameter at sea level; its steep upper slopes are generally snow-covered year round. Little is known about Carlisle volcano’s structure and composition. The topography suggests that the lower slopes of Carlisle are slightly more irregular in form and more dissected by erosion than are the uppermost slopes. According to Sekora (1973), the western margin of the island consists of a small plateau at an elevation of 50 m, suggesting that the Carlisle stratovolcano is constructed on an emergent marine terrace.”

Chiginagak

From Miller and others (1998): “Chiginagak volcano is a symmetric composite cone about 8 km in diameter built on late Tertiary volcanic rocks and Jurassic-Cretaceous sedimentary rocks and located on a southwest trending regional anticline (Detterman and others, 1983). A deep breach on the south flank on the volcano extends to a small summit crater and exposes widespread alteration of interbedded lava flows and breccias near the summit of the volcano. Snow and ice cover much of the uppermost 1000 m of the cone.

Cleveland

From Miller and others (1998): “Mt. Cleveland is a stratovolcano that comprises the entire western half of Chuginadak Island, 40 km west of Umnak. Distinctively conical and symmetrical in form, Cleveland is about 8.5 km in diameter and is joined to the rugged, though lower, eastern half of the island by a low, narrow strip of land. Sekora (1973) reports that this strip is dotted with “lava flow, cinder, and ash patches, and conical hills.”

Dutton

From Miller and others (1998): “Mount Dutton is a small snow- and ice-covered calc-alkaline volcanic center with an approximate diameter of 5 km (not including the isolated large intra-canyon lava flow 5 km southwest of the summit) and an estimated volume of 7-15 cubic km. The volcano is built on an east-sloping basement of hydrothermally altered Tertiary volcanic rocks (Kennedy and Waldron, 1955).

“The volcano consists of a central multiple dome complex (Davies and others, 1988) in which successive domes shouldered aside earlier domes and the enclosing cone-building volcanic rocks. Some hydrothermal alteration occurs along vertical contacts between adjacent domes. The dome-building activity and associated collapse has caused extensive destruction of cone-building lava flows and, to a lesser extent the domes themselves. This has resulted in the massive, thick-bedded debris flows 100-200 m thick that surround and mantle the central dome complex.

Emmons Lake Volcanic Center

From Wood and Kienle (1990): “The Emmons Lake volcanic center is the site of a large stratovolcano with a pre-caldera volume of 300-400 cubic km and one of the largest calderas in the Aleutian arc. The center is very complex; at least two large caldera-forming eruptions have occurred in Late Quaternary time, and voluminous post-caldera volcanism continues to the present. The entire area has been subjected to multiple glaciations, and ice fields present occur in the caldera. A small lake in the southwest corner of the caldera drains to the Pacific Ocean through a breach in the southeast rim of the caldera.

Fisher

From Miller and others (1998): “Fisher caldera is 11 km wide by 18 km long, and has a maximum internal relief of 929 m. It is one of at least three volcanoes on Unimak Island that have been active in historical time.

“The caldera is remarkable in size – one of the largest calderas in the Aleutian arc – and for the mobility of the ash flows that resulted from the caldera-forming eruption about 9100 years ago (Miller and Smith, 1977; 1987). The ash flows reached the Pacific Ocean 8 km to the southeast, and swept part way up the slopes of stratovolcanoes to the east and southwest. To the north, ash flows crossed 15 km of lowland to reach the Tugamak Range, surmounted drainage divides as much as 400 m above the lowland surface in the range, and continued northward an additional 8 km to the Bering Sea coastline. Miller and Smith (1977) inferred that the ash flows had unusually high velocities to cross such topographic barriers and suggested that the high velocities resulted by ash fall-back from a high eruption column.

Fourpeaked

From Wood and Kienle (1990): “Fourpeaked Mountain consists of small isolated volcanic exposures surrounded by the Fourpeaked Glacier. The exposures are found along ridge crests and cliff faces on the sides of ridges that radiate out from the ice-covered summit. Lava flows are interlayered with volcanic agglomerate in the isolated exposures.

Gilbert

From Wood and Kienle (1990): “Mount Gilbert is a small extinct volcano on northernmost Akun Island. Its northern flank is steep and heavily eroded, presumably by the sea, while its southern flank is little dissected. The summit region has been completely eroded and was presumably north of, and higher than, the present summit. A 20,000 square m zone of slightly older fumarolically altered rock exists 1.5 km northeast of the current summit. Prior to 1948, active fumaroles in this area produced steam plumes visible from a distance; fumarolic activity has since stopped. The altered ground was the site of an unsuccessful attempt to mine sulfur in the 1920’s.”

Great Sitkin

From Miller and others (1998): “Great Sitkin Volcano occupies most of the northern half of Great Sitkin Island, a member of the Andreanof Islands group in the central Aleutian Islands. The volcano is roughly oval-shaped, 8 by 11 km at the base, with the long axis trending east-west. It is a composite structure consisting of the remains of an older, decapitated volcano and a younger parasitic cone that collapsed forming a small caldera (0.8 by 1.2 km) on the west flank (Simons and Mathewson, 1955). The highest point on the island is apparently a remnant of the former central volcano’s eastern rim. Most of the constructional surface of the cone has been deeply eroded. A steep-sided, recently emplaced dome (unit Qgd) occupies the center of the caldera at an elevation of 1220 m. The dome is 183 m high, 0.4 km wide, and 0.6 km long with a blocky, flat top. Five small plugs (unit Qa) are intruded into the northwest slope of the cone; three of the plugs are aligned in a northwest direction from the crater, and the remaining two are aligned north-northwest.

Griggs

From Wood and Kienle (1990): “A spectacular, little-dissected cone, Mount Griggs towers 1,700 m above the north margin of the Valley of Ten Thousand Smokes, its summit only 10 km north of Novarupta. Uniquely among the stratovolcanoes of the Katmai district, it lies 10 km behind (northwest of) the remarkably linear (N66E-trending) volcanic front defined by Martin, Mageik, Trident, Katmai, and Snowy Mountain centers.

Iliamna

From Miller et al (1998): “Iliamna volcano is a broad, deeply dissected and highly altered, roughly cone-shaped mountain at the north end of a 5-km-long ridge trending N10W. Most of the volcano is covered by perennial snow and ice and numerous glaciers radiate from the summit area. Large avalanche deposits occur on the flanks of the volcano, particularly down the Umbrella Glacier on the southwest side of the volcano.

Kasatochi

From Miller and others (1998): “Kasatochi Island, like Gareloi, Bogoslof, and several other volcanoes in the western Aleutian arc, represents the emergent summit of a predominantly submarine volcano. The island consists of a single, undissected cone with a central lake-filled crater about 0.75 km in diameter. A maximum height of 314 m is on the southern crater rim; elevation of the lake is less than about 60 m. Kay (1990) reports a lava dome on the northwest side of the cone at an elevation of ~150 m.

Katmai

“The volcano is one of five stratovolcanoes near the Novarupta dome, source of the voluminous pyroclastic flows erupted in 1912 (Hildreth, 1983). It consists chiefly of lava flows, pyroclastic rocks, and non-welded to agglutinated air fall (Fenner, 1920; Hildreth, 1983). The Quaternary volcanic rocks at Katmai and adjacent cones are less than 1500 m thick (Hildreth, 1983). Much of the volcano is mantled by snow and ice and several valley glaciers radiate out from the flanks and three glaciers originating from the upper caldera walls descend into the crater to the lake (Motyka and Benson, 1975).

Kiska

From Miller and others (1998): “Kiska Volcano is a stratovolcano, 8.5 by 6.4 km in diameter at its base and 1221 m high, on the northern end of Kiska Island. A slightly elliptical crater, about 0.4 km in diameter and breached on the north, occupies the summit. A parasitic 30-m-high cinder cone, formed in 1962 near sea level, occurs at Sirius Point and an older parasitic cone, now leveled by marine erosion, occurs at sea level 5.6 km southwest of Kiska Volcano.

Kupreanof

From Wood and Kienle (1990): “The Stepovak Bay group is a chain of five volcanoes at the southwest end of a N40E oriented linear segment of the Aleutian arc on the Alaska Peninsula. This same segment includes the better known Veniaminof and Aniakchak calderas. Three of the Stepovak Bay volcanoes (2, 4, and Kupreanof) have clearly had Holocene eruptions, resulting in three small debris flows filling late Pleistocene glacial valleys, and a small cinder cone and associated lava flow. The other two volcanoes (1 and 3) do not show unmistakable evidence of Holocene activity. They have ice-filled summit craters 500 m (1) and 300 m (3) in diameter that may be late Pleistocene age. These volcanoes have contributed to extensive late Tertiary and Quaternary lava flows, some extending near sea level.

Mageik

From Miller and others (1998): “Mount Mageik is a broad cone-shaped volcano that rests on a basement of Jurassic sedimentary rocks at the northeast end of a 12-km-long basement ridge shared by neighboring Mount Martin. The summit area, which is largely ice-covered, consists of a central high peak (elevation 2165 m) and three smaller topographic highs, each a separate vent-cone. A small (

Novarupta

From Miller and others (1998): “The Novarupta dome is about 400 m in diameter and 65 m high at its center (Curtis, 1968), and is surrounded by a 2-km-wide, funnel-shaped structure (Hildreth, 1983; Goodliffe and others, 1991). The surface of the dome is completely fractured into chaotic blocks and crumble breccia. The dome is a plug-like feature emplaced within a low ejecta ring. Prominent scarps along the flanks of Baked, Falling, and Broken Mountains surrounding the Novarupta depression indicate considerable subsidence occurred following the 1912 eruption. Nearby stratovolcanoes (including Trident and Katmai) form a volcanic front trending N65E; Novarupta lies about 4 km behind the front. Linear fractures normal to the front extend between Novarupta and Trident (Hildreth, 1987).”

Redoubt

From Miller et al (1998): “Redoubt Volcano is a steep-sided cone about 10 km in diameter at its base and with a volume of 30-35 cubic kilometers. The volcano is composed of intercalated pyroclastic deposits and lava flows and rests on Mesozoic granitic rocks of the Alaska-Aleutian Range batholith (Till and others, 1993; 1994). It has been moderately dissected by the action of numerous alpine glaciers. A 1.8-km-wide, ice-filled summit crater is breached on the north side by a northward-flowing glacier, informally known as the Drift Glacier, which spreads into a piedmont lobe in the upper Drift River Valley. The most recently active vent is located on the north side of the crater at the head of the Drift glacier. Holocene lahar deposits in the Crescent River and Drift River valleys extend downstream as far as Cook Inlet.”

Sanford

From Wood and Kienle (1990): “Mount Sanford, a very large dissected shield with an impressive bulbous top, is the highest volcano in the Wrangell volcanic field. Most of the upper part (>2,500 m) is covered by perennial snow and ice, making study and observation difficult. The principal “window” through the ice cap is the great amphitheater at the head of the Sanford Glacier which rises more than 2,400 m in less than 1,500 m. Data from unpublished geologic mapping around the volcano’s base, and fly-by observations of the great amphitheater and other cirques, indicate that the upper part of Mount Sanford is a young feature, * * * that developed on a base of at least three coalescing andesitic shield volcanoes, referred to as the north, west, and south Sanford eruptive centers. The centers may contain shallow dacite and andesite intrusives, dike complexes, vent deposits, and may be the locus of linear rift vents; all centers are marked by topographic highs.”

Seguam

From Miller and others (1998): “Seguam Island consists of the remnants of two late Quaternary calderas. Holocene volcanic cones occur in both of the calderas and a third Holocene cone lies at the east end of the island. Pyre Peak, commonly referred to as Sequam volcano, highest of the young cones, dominates the western half of the island and occupies the center of the western caldera (Singer and others, 1992) that is defined by remnants of a semi-circular ridge about 3 km in original diameter and about 700 m high. A Holocene basalt field surrounds Pyre Peak (Singer and others, 1992) extending down to shoreline. This general area has been the site of most if not all historical volcanic activity. Late Quaternary lavas and pyroclastic rocks ranging in age form 1.1 Ma to 0.03 Ma underlie the basalt. The two Holocene cones to the east are surrounded by andesite and dacite lava flows with well preserved constructional features (Singer and others, 1992).”

Snowy

From Hildreth and Fierstein, 2003: “Snowy Mountain is a small andesite-dacite volcanic center that straddles the rangecrest northeast of the main Katmai cluster, separated by about 10 km from Mount Griggs. Snowy Mountain was named during the National Geographic Society expedition to Katmai in 1917 (Griggs, 1922, p. 131). The name chosen evidently reflected how impressed those explorers were with its extensive mantle of snow and ice as seen from upper Katmai River, which was their closest approach to the edifice. Rising to an elevation of 7,090 ft (2,161 m), Snowy Mountain remains today the source of 10 substantial glaciers. Because glacial ice still covers nearly 90 percent of the edifice, the principal rock exposures are limited to narrow ice-bounded ar’tes at higher elevations and ice-scoured lava-flow benches at lower elevations.

Ukinrek Maars

From Miller and others (1998): “Ukinrek Maars are a pair of phreatomagmatic explosion vents that formed on a low (less than 100 m high), 4-km-long, ridge in the Bering Sea Lowland 1.5 km south of Becharof Lake and 12 km northwest of Peulik Volcano. West Maar, elliptical in shape and up to 170 m in diameter and 35 m deep, formed on the northwest end of the ridge (Kienle and others, 1980). East Maar lies 600 m east of West Maar at a lower elevation. It is circular, up to 300 m in diameter and 70 m deep, and has a 49-m-high central lava dome that is now partly covered by a crater lake. Location of the maars apparently coincides with, and may be controlled by, the intersection of the Bruin Bay fault and regional structures (Kienle and others, 1980; Detterman and others, 1983).”

Vsevidof

From Miller and others (1998): “Mount Vsevidof is a symmetrical stratovolcano near the southwest end of Umnak Island. It is about 10 km wide at the base and steepens from 15 degrees at 300 m altitude to about 30 degrees near the summit. A circular crater, 1.2 km in diameter, occupies the summit. Glacial ice fills the crater and extends down the north and east flanks of the cone; some of these glacial tongues have incised narrow canyons up to 120 m deep.

“A chain of small cinder cones (unit Qc) below altitude 1220 m parallels a rift on the western flank (Byers, 1959). Young flows of andesite and dacite (unit Qvf) were extruded from this rift and from other vents on north and south flanks of the cone. Pyroclastic deposits, apparently products of a culminating summit eruption, attain a thickness of more than 30 m at the crater but thin downslope.

Westdahl

From Miller and others (1998): “Westdahl Peak, including nearby Faris Peak and Pogromni volcano, is located on a gently sloping plateau (mean elevation 1220 m) that may represent the surface of a truncated ancestral cone. Westdahl Peak is about 18 km in diameter at the base.

“The size of the postulated ancestral cone is about 19 x 30 km at sea level, making it one of the largest volcanoes in the Aleutian Islands be it a stratovolcano or a shield. The entire ancestral cone has been extensively dissected by erosion, with the northeast-facing slopes steeper and of greater relief than the other slopes.

Wrangell

From Miller and others (1998): “Mount Wrangell is a large andesitic shield volcano with a volume of about 900 cubic kilometers (Nye, 1983). Its top is capped by a 4 by 6 km, ice-filled summit caldera whose depth may exceed 1 km (Benson and Motyka, 1979). The caldera is apparently of non-explosive origin (Richter and others, 1984) formed in response to the withdrawal of magma from high-level reservoirs beneath the summit area. Three small (

Yunaska

From Miller and others (1998): “Yunaska Island lies near the west end of the Islands of the Four Mountains group and is flanked by Chagulak and Amukta Islands on the west and the remainder of the group on the east. Yunaska Island is roughly oval in form and about 23 km long. It consists of two volcanic centers separated by a flat valley with moderately sloping walls. The western volcano, 950 m high, is the eroded remnant of a series of four overlapping stratocones (Nicolaysen and others, 1992); a group of cinder cones and fissure flows extends from the west end of the complex. This western volcano has presumably not been active in historical time.