AVO Staff Directory:

Mt Veniaminof is a large active stratovolcano located on the Alaska Peninsula (56.28 N, 1598 W). We present results of the first geophysical survey of the icefield that fills much of the 10km x 8km caldera that was most recently modified during the last major eruption roughly 3700 BP. The subglacial topography and ice volume are derived from an 8MHz radio-echo sounding survey conducted in July 2005. Prominent internal reflectors are assumed to be isochronal ash/acid deposits related to local eruptions. Accumulation rates and basal melt rates are calculated using a Nye onedimensional steady-state accumulation model applied at a location that approximates an ice divide and calibrated by matching internal reflectors with published records of recent local volcanic eruptions. The model yields order of magnitude estimates of the accumulation rate of 4myr^-1 water equivalent and 2myr^-1 of basal melt.

Welch, B.C., Dwyer, Kieran, Helgen, Michael, Waythomas, C.F., and Jacobel, R.W., 2007, Geophysical survey of the intra-caldera icefield of Mt Veniaminof, Alaska: Annals of Glaciology, v. 45, p. 58-65.

Tephra-fall deposits from Cook Inlet volcanoes were detected in sediment cores from Tustumena and Paradox Lakes, Kenai Peninsula, Alaska, using magnetic susceptibility and petrography. The ages of tephra layers were estimated using 21 14C ages on macrofossils. Tephras layers are typically fine, gray ash, 1-5 mm thick, and composed of varying proportions of glass shards, pumice, and glass-coated phenocrysts. Of the two lakes, Paradox Lake contained a higher frequency of tephra (0.8 tephra/100 yr; 109 over the 13,200-yr record). The unusually large number of tephra in this lake relative to others previously studied in the area is attributed to the lake's physiography, sedimentology, and limnology. The frequency of ash fall was not constant through the Holocene.

de Fontaine, C.S., Kaufman, D.S., Anderson, R.S., Werner, Al, Waythomas, C.F., and Brown, T.A., 2007, Late Quaternary distal tephra-fall deposits in lacustrine sediments, Kenai Peninsula, Alaska: Quaternary Research, v. 68, p. 64-78, doi:10.1016/j.yqres.2007.03.006.

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.

Waythomas, C.F., 2007, Mid-Holocene sector collapse at Mount Spurr volcano, south-central Alaska, in, Haeussler, P.J., and Galloway, J.P., eds., Studies by the U.S. Geological Survey in Alaska, 2006: U.S. Geological Survey Professional Paper 1739-C, 15 p., available at http://pubs.usgs.gov/pp/pp1739/c/ .
USGS website with link to PDF
full-text PDF on AVO server : 28.7 MB

Iliamna is an andesitic stratovolcano of the Aleutian arc with regular gas and steam emissions and mantled by several large glaciers. Iliamna Volcano exhibits an unusual combination of frequent and large ice-rock avalanches in the order of 1×106 m3 to 3×107 m3 with recent return periods of 2–4 years. We have reconstructed an avalanche event record for the past 45 years that indicates Iliamna avalanches occur at higher frequency at a given magnitude than other mass failures in volcanic and alpine environments. Iliamna Volcano is thus an ideal site to study such mass failures and its relation to volcanic activity.

Huggel, Christian, Caplan-Auerbach, Jacqueline, Waythomas, C.F., and Wessels, Rick, 2007, Monitoring and modeling ice-rock avalanches from ice-capped volcanoes: a case study of frequent large avalanches on Iliamna Volcano, Alaska: Journal of Volcanology and Geothermal Research, v. 168, p. 114-136, doi:10.1016/j.jvolgeores.2007.08.009.

Many of the world's active volcanoes are situated on or near coastlines. During eruptions, diverse geophysical mass flows, including pyroclastic flows, debris avalanches, and lahars, can deliver large volumes of unconsolidated debris to the ocean in a short period of time and thereby generate tsunamis. Deposits of both hot and cold volcanic mass flows produced by eruptions of Aleutian arc volcanoes are exposed at many locations along the coastlines of the Bering Sea, North Pacific Ocean, and Cook Inlet, indicating that the flows entered the sea and in some cases may have initiated tsunamis.

Waythomas, C.F., Watts, P., and Walder, J.S., 2006, Numerical simulation of tsunami generation by cold volcanic mass flows at Augustine Volcano, Alaska: Natural Hazards and Earth System Sciences, v. 6, p. 671-685, available online at http://www.nat-hazards-earth-syst-sci.net/6/671/2006/ .
website link
full-text PDF : 8.5 MB

The Emmons Lake volcanic center is a large stratovolcano complex on the Alaska Peninsula near Cold Bay, Alaska. The volcanic center includes several ice- and snow-clad volcanoes within a nested caldera structure that hosts Emmons Lake and truncates a shield-like ancestral Mount Emmons edifice. From northeast to southwest, the main stratovolcanoes of the center are: Pavlof Sister, Pavlof, Little Pavlof, Double Crater, Mount Hague, and Mount Emmons. Several small cinder cones and vents are located on the floor of the caldera and on the south flank of Pavlof Volcano. Pavlof Volcano, in the northeastern part of the center, is the most historically active volcano in Alaska (Miller and others, 1998) and eruptions of Pavlof pose the greatest hazards to the region.

Waythomas, C.F., Miller, T.P., and Mangan, M.T., 2006, Preliminary Volcano Hazard Assessment for the Emmons Lake Volcanic Center, Alaska: Anchorage, Alaska, U.S. Geological Survey, Scientific Investigations Report 2006-5248, 33 p., 1 sheet, available online at http://www.avo.alaska.edu/pdfs/SIR2006-5248.pdf .
map sheet : 2.4 MB
full-text PDF : 4.08 MB

"Great Sitkin Volcano is a composite andesitic stratovolcano on Great Sitkin Island, a small (14 x 16 km), circular volcanic island in the western Aleutian Islands of Alaska. Great Sitkin Island is located about 35 kilometers northeast of the community of Adak on Adak Island and 130 kilometers west of the community of Atka on Atka Island. Great Sitkin Volcano is an active volcano and has erupted at least eight times in the past 250 years (Miller and others, 1998). The most recent eruption in 1974 caused minor ash fall on the flanks of the volcano and resulted in the emplacement of a lava dome in the summit crater."

Waythomas, C. F., Miller, T. P., and Nye, C. J., 2003, Preliminary volcano-hazard assessment for Great Sitkin Volcano, Alaska: U.S. Geological Survey Open-File Report OF 03-0112, 25 p., 1 sheet.
full-text PDF : 18.5 MB
map sheet plate (PDF) : 2 MB

"Recent studies by the Alaska Volcano Observatory have been focused on addressing this concern by studying the geology and eruptive history of historically active volcanoes in the Aleutian Arc to better understand the characteristics of future explosive eruptions. Here, we report results from our study of Kanaga Volcano, an active calc-alkaline stratovolcano in the western Aleutian Islands of Alaska."

Waythomas, C. F., Miller, T. P., and Nye, C. J., 2003, Geology and late Quaternary eruptive history of Kanaga Volcano, a calc-alkaline stratovolcano in the western Aleutian Islands, Alaska: in Galloway, J. P., (ed.), Studies by the U.S. Geological Survey in Alaska, 2001, U.S. Geological Survey Professional Paper PP 1678, p. 181-197.
full-text PDF : 1.5 MB

"The Emmons Lake Volcanic Center on the Alaska Peninsula of southwestern Alaska is the site of at least two rhyolitic caldera-forming eruptions (C1 and C2) of late Quaternary age that are possibly the largest of the numerous caldera-forming eruptions known in the Aleutian arc. The deposits produced by these eruptions are widespread (eruptive volumes of >50 km3 each), and their association with Quaternary glacial and eolian deposits on the Alaska Peninsula and elsewhere in Alaska and northwestern Canada enhances the likelihood of establishing geochronological control on Quaternary stratigraphic records in this region. The pyroclastic deposits associated with the second caldera-forming eruption (C2) consist of loose, granular, airfall and pumice-flow deposits that extend for tens of kilometres beyond Emmons Lake caldera, reaching both the Bering Sea and Pacific Ocean coastlines north and south of the caldera."

Mangan, M. T., Waythomas, C. F., Miller, T. P., and Trusdell, F. A., 2003, Emmons Lake Volcanic Center, Alaska Peninsula: source of the late Wisconsin Dawson tephra, Yukon Territory, Canada: Canadian Journal of Earth Sciences, v. 40, n. 7, p. 925-936.

Waythomas, C. F., Miller, T. P., and Nye, C. J., 2003, Preliminary geologic map of Great Sitkin Volcano, Alaska: U.S. Geological Survey Open-File Report OF 03-0036, unpaged, 1 sheet, scale 1:63,360.
PDF : 3 MB

Miller, T. P., Waythomas, C. F., and Nye, C. J., 2003, Preliminary geologic map of Kanaga Volcano, Alaska: U.S. Geological Survey Open-File Report OF 03-0113, unpaged, 2 sheets, scale 1:20,000.
sheet 1 (PDF) : 1.5 MB
sheet 2 (PDF) : 10 MB

"Hayes Volcano is an ice- and snow-mantled, deeply eroded volcanic massif located in the northern Tordrillo Mountains of the north-central Cook Inlet region about 135 kilometers northwest of Anchorage, Alaska. Hayes Volcano consists of a glacially dissected, poorly exposed cluster of lava domes. No historical eruptions of Hayes Volcano are known, and the last period of major eruptive activity occurred within a time interval of 4,400 to 3,600 years ago. During this period, explosive Plinian-style eruptions occurred that dispersed volcanic ash over large areas of interior, south-central, and southeastern Alaska. Pyroclastic flows produced during these eruptions descended Hayes Glacier and entered the Hayes River drainage. The pyroclastic flows initiated volcanic debris flows or lahars that flowed down the Hayes River, into the Skwentna River, and probably reached the Yentna River about 110 kilometers downstream from the volcano. The last major eruptive period of Hayes Volcano may have spanned about 200 years, and at least one of the eruptions during this interval was possibly the largest eruption of any volcano in the Cook Inlet region in the past 10,000 years."

Waythomas, C. F., and Miller, T. P., 2002, Preliminary volcano-hazard assessment for Hayes volcano, Alaska: U.S. Geological Survey Open-File Report OF 02-0072, 33 p.
full-text PDF : 3.98 MB

"Mount Spurr volcano is an ice- and snow-covered stratovolcano complex located in the north-central Cook Inlet region about 100 kilometers west of Anchorage, Alaska. Mount Spurr volcano consists of a breached stratovolcano, a lava dome at the summit of Mount Spurr, and Crater Peak vent, a small stratocone on the south flank of Mount Spurr volcano. Historical eruptions of Crater Peak occurred in 1953 and 1992. These eruptions were relatively small but explosive, and they dispersed volcanic ash over areas of interior, south-central, and southeastern Alaska. Individual ash clouds produced by the 1992 eruption drifted east, north, and south. Within a few days of the eruption, the south-moving ash cloud was detected over the North Atlantic. Pyroclastic flows that descended the south flank of Crater Peak during both historical eruptions initiated volcanic-debris flows or lahars that formed temporary debris dams across the Chakachatna River, the principal drainage south of Crater Peak. Prehistoric eruptions of Crater Peak and Mount Spurr generated clouds of volcanic ash, pyroclastic flows, and lahars that extended to the volcano flanks and beyond. A flank collapse on the southeast side of Mount Spurr generated a large debris avalanche that flowed about 20 kilometers beyond the volcano into the Chakachatna River valley. The debris-avalanche deposit probably formed a large, temporary debris dam across the Chakachatna River."

Waythomas, C. F., and Nye, C. J., 2002, Preliminary volcano-hazard assessment for Mount Spurr Volcano, Alaska: U.S. Geological Survey Open-File Report OF 01-0482, 46 p.
full-text PDF : 11.25 MB

"Kanaga Volcano is a steep-sided, symmetrical, cone-shaped, 1307 meter high, andesitic stratovolcano on the north end of Kanaga Island in the western Aleutian Islands of Alaska. Kanaga Island is an elongated, lowrelief (except for the volcano) island, located about 35 kilometers west of the community of Adak on Adak Island and is part of the Andreanof Islands Group of islands. Kanaga Volcano is one of the 41 historically active volcanoes in Alaska and has erupted numerous times in the past 11,000 years, including at least 10 eruptions in the past 250 years (Miller and others, 1998). The most recent eruption occurred in 1993-95 and caused minor ash fall on Adak Island and produced blocky aa lava flows that reached the sea on the northwest and west sides of the volcano (Neal and others, 1995)."

Waythomas, C. F., Miller, T. P., and Nye, C. J., 2002, Preliminary volcano-hazard assessment for Kanaga Volcano, Alaska: U.S. Geological Survey Open-File Report OF 02-0397, 27 p., 1 sheet.
full-text PDF : 38.5 MB
map sheet plate (PDF) : 17.5 MB

"Aniakchak is an active volcano located on the Alaska Peninsula 670 kilometers southwest of Anchorage. The volcano consists of a dramatic, 10-kilometer-diameter, 0.5 to 1.0-kilometer-deep caldera that formed during a catastrophic eruption 3,500 years ago. Since then, at least a dozen separate vents within the caldera have erupted, often explosively, to produce lava flows and widespread tephra (ash) deposits. The most recent eruption at Aniakchak occurred in 1931 and was one of the largest explosive eruptions in Alaska in the last 100 years. Although Aniakchak volcano presently shows no signs of unrest, explosive and nonexplosive eruptions will occur in the future. Awareness of the hazards posed by future eruptions is a key factor in minimizing impact."

Neal, Christina, McGimsey, R. G., Miller, T. P., Riehle, J. R., and Waythomas, C. F., 2001, Preliminary volcano-hazard assessment for Aniakchak Volcano, Alaska: U.S. Geological Survey Open-File Report OF 00-0519, 35 p.
website with links to PDFs
full-text PDF : 24.2 MB
map sheet plate PDF (for viewing) : 3.1 MB

Debris avalanches entering the sea at Augustine Volcano, Alaska have been proposed as a mechanism for generating tsunamis. Historical accounts of the 1883 eruption of the volcano describe 6- to 9-meter-high waves that struck the coastline at English Bay (Nanwalek), Alaska about 80 kilometers east of Augustine Island. These accounts are often cited as proof that volcanigenic tsunamis from Augustine Volcano are significant hazards to the coastal zone of lower Cook Inlet. This claim is disputed because deposits of unequivocal tsunami origin are not evident at more than 50 sites along the lower Cook Inlet coastline where they might be preserved.

Waythomas, C. F., 2000, Reevaluation of tsunami formation by debris avalanche at Augustine Volcano, Alaska: in Keating, B. H., Waythomas, C. F., and Dawson, A. G., (eds.), Landslides and tsunamis, Pure and Applied Geophysics, v. 157, n. 6, p. 1145-1188.

"Akutan Volcano is one of the most active volcanoes in the Aleutian arc, but until recently little was known about its history and eruptive character. Following a brief but sustained period of intense seismic activity in March 1996, the Alaska Volcano Observatory began investigating the geology of the volcano and evaluating potential volcanic hazards that could affect residents of Akutan Island."

Waythomas, C. F., 1999, Stratigraphic framework of Holocene volcaniclastic deposits, Akutan Volcano, east-central Aleutian Islands, Alaska: Bulletin of Volcanology, v. 61, n. 3, p. 141-161.

"Iliamna Volcano is a 3,053-meter-high, ice- and snow-covered stratovolcano in the southwestern Cook Inlet region about 225 kilometers southwest of Anchorage and about 100 kilometers northwest of Homer. Historical eruptions of Iliamna Volcano have not been positively documented; however, the volcano regularly emits steam and gas, and small, shallow earthquakes are often detected beneath the summit area. The most recent eruptions of the volcano occurred about 300 years ago, and possibly as recently as 90-140 years ago. Prehistoric eruptions have generated plumes of volcanic ash, pyroclastic flows, and lahars that extended to the volcano flanks and beyond. Rock avalanches from the summit area have occurred numerous times in the past. These avalanches flowed several kilometers down the flanks and at least two large avalanches transformed to cohesive lahars. The number and distribution of known volcanic ash deposits from Iliamna Volcano indicate that volcanic ash clouds from prehistoric eruptions were significantly less voluminous and probably less common relative to ash clouds generated by eruptions of other Cook Inlet volcanoes. Plumes of volcanic ash from Iliamna Volcano would be a major hazard to jet aircraft using Anchorage International Airport and other local airports, and depending on wind direction, could drift at least as far as the Kenai Peninsula and beyond. Ashfall from future eruptions could disrupt oil and gas operations and shipping activities in Cook Inlet. Because Iliamna Volcano has not erupted for several hundred years, a future eruption could involve significant amounts of ice and snow that could lead to the formation of large lahars and downstream flooding."

Waythomas, C. F., and Miller, T. P., 1999, Preliminary volcano-hazard assessment for Iliamna Volcano, Alaska: U.S. Geological Survey Open-File Report OF 99-0373, 31 p., 1 sheet, scale unknown.
full-text PDF : 2.84 MB
map sheet plate : 1.0 MB

"Augustine Volcano is a 1250-meter-high stratovolcano in southwestern Cook Inlet about 280 kilometers southwest of Anchorage and within about 300 kilometers of more than half of the population of Alaska. Explosive eruptions have occurred six times since the early 1800s (1812, 1883, 1935, 1964-65, 1976, and 1986). The 1976 and 1986 eruptions began with an initial series of vent-clearing explosions and high vertical plumes of volcanic ash followed by pyroclastic flows, surges, and lahars on the volcano flanks. Unlike some prehistoric eruptions, a summit edifice collapse and debris avalanche did not occur in 1812, 1935, 1964-65, 1976, or 1986. However, early in the 1883 eruption, a portion of the volcano summit broke loose forming a debris avalanche that flowed to the sea. The avalanche initiated a small tsunami reported on the Kenai Peninsula at English Bay, 90 kilometers east of the volcano. Plumes of volcanic ash are a major hazard to jet aircraft using Anchorage International and other local airports. Ashfall from future eruptions could disrupt oil and gas operations and shipping activities in Cook Inlet. Eruptions similar to the historical and prehistoric eruptions are likely in Augustine's future."

Waythomas, C. F., and Waitt, R. B., 1998, Preliminary volcano-hazard assessment for Augustine Volcano, Alaska: U.S. Geological Survey Open-File Report OF 98-0106, 39 p., 1 plate, scale unknown.
full-text PDF : 2.08 MB
map sheet plate : 3.14 MB

Akutan Volcano is a 1100-meter-high stratovolcano on Akutan Island in the east-central Aleutian Islands of southwestern Alaska. The volcano is located about 1238 kilometers southwest of Anchorage and about 56 kilometers east of Dutch Harbor/Unalaska. Eruptive activity has occurred at least 27 times since historical observations were recorded beginning in the late 1700's. Recent eruptions produced only small amounts of fine volcanic ash that fell primarily on the upper flanks of the volcano. Small amounts of ash fell on the Akutan Harbor area during eruptions in 1911, 1948, 1987, and 1989. Plumes of volcanic ash are the primary hazard associated with eruptions of Akutan Volcano and are a major hazard to all aircraft using the airfield at Dutch Harbor or approaching Akutan Island. Eruptions similar to historical Akutan eruptions should be anticipated in the future. Although unlikely, eruptions larger than those of historical time could generate significant amounts of volcanic ash, fallout, pyroclastic flows, and lahars that would be hazardous to life and property on all sectors of the volcano and other parts of the island, but especially in the major valleys that head on the volcano flanks. During a large eruption, an ash cloud could be produced that may be hazardous to aircraft using the airfield at Cold Bay and the airspace downwind from the volcano. In the event of a large eruption, volcanic ash fallout could be relatively thick over parts of Akutan Island and volcanic bombs could strike areas more than 10 kilometers from the volcano."

Waythomas, C. F., Power, J. A., Richter, D. H., and McGimsey, R. G., 1998, Preliminary volcano-hazard assessment for Akutan Volcano east-central Aleutian Islands, Alaska: U.S. Geological Survey Open-File Report OF 98-0360, 36 p., 1 plate, scale unknown.
full-text PDF : 1.68 MB
map sheet plate (PDF) : 2.62 MB

Richter, D. H., Waythomas, C. F., McGimsey, R. G., and Stelling, P. L., 1998, Geologic map of Akutan Island, Alaska: U.S. Geological Survey Open-File Report OF 98-0135, 22 p., 1 sheet, scale 1:48,000.
website with PDF link
full-text PDF : 688 KB

A discontinuous pumiceous sand, a few centimeters to tens of centimeters thick, is located up to 15 m above mean high tide within Holocene peat along the northern Bristol Bay coastline of Alaska. The bed consists of fine-to-coarse, poorly to moderately wellsorted, pumice-bearing sand near the top of a 2-m-thick peat sequence. The sand bed contains rip-up clasts of peat and tephra and is unique in the peat sequence. Major element compositions of juvenile glass from the deposit and radiocarbon dating of enclosing peat support correlation of the pumiceous sand with the caldera-forming eruption of Aniakchak Volcano.

Waythomas, C. F., and Neal, C. A., 1998, Tsunami generation by pyroclastic flow during the 3500-year B.P. caldera-forming eruption of Aniakchak Volcano, Alaska: Bulletin of Volcanology, v. 60, n. 2, p. 110-124.

"Redoubt Volcano is a stratovolcano located within a few hundred kilometers of more than half of the population of Alaska. This volcano has erupted explosively at least six times since historical observations began in 1778. The most recent eruption occurred in 1989-90 and similar eruptions can be expected in the future. The early part of the 1989-90 eruption was characterized by explosive emission of substantial volumes of volcanic ash to altitudes greater than 12 kilometers above sea level and widespread flooding of the Drift River valley. Later, the eruption became less violent, as developing lava domes collapsed, forming short-lived pyroclastic flows associated with low-level ash emission. Clouds of volcanic ash had significant effects on air travel as they drifted across Alaska, over Canada, and over parts of the conterminous United States causing damage to jet aircraft. Economic hardships were encountered by the people of south-central Alaska as a result of ash fallout. Based on new information gained from studies of the 1989-90 eruption, an updated assessment of the principal volcanic hazards is now possible. Volcanic hazards from a future eruption of Redoubt Volcano require public awareness and planning so that risks to life and property are reduced as much as possible."

Waythomas, C. F., Dorava, J. M., Miller, T. P., Neal, C. A., and McGimsey, R. G., 1997, Preliminary volcano-hazard assessment for Redoubt Volcano, Alaska: U.S. Geological Survey Open-File Report OF 97-857, 40 p., 1 plate, scale unknown.
full-text PDF : 1.76 MB
map sheet plate PDF : 5.61 MB

"Recent eruptions of volcanoes in the Cook Inlet region of south-central Alaska provide insight into the environmental and economic consequences of hydrologic processes associated with volcanic activity."

Dorava, J. M., and Waythomas, C. F., 1995, Hydrologic hazards at recently active volcanoes in the Cook Inlet Region, Alaska: in Herrman, R., (ed.), Annual summer symposium -- 1995, Water resources and environmental hazards: emphasis on hydrologic and cultural insight in the Pacific Rim, Honolulu, HI, American Water Resources Association, p. 91-98.

"Because of their basin-like shape, calderas on many Alaskan volcanoes are geomorphic repositories for water, ice, and snow. The heat flux associated with these volcanoes enhances melting of ice and snow, and caldera lakes commonly result. The caldera rim is a type of natural dam that may impound a substantial amount of water depending on the size of the caldera and the integrity of the bedrock that forms the rim. Failure of a caldera dam and subsequent catastrophic drainage of the intracaldera lake can pose a serious hazard to life and property situated in the flood path (Bolt and others, 1977, p. 94-95). In this report of our preliminary observations, we present geomorphic and stratigraphic evidence for (1) a former extensive intracaldera lake at Aniakchak volcano, (2) catastrophic drainage of this lake by failure of the caldera rim dam, and (3) possible linkages between dam failure and the recent eruptive history of the volcano."

McGimsey, R. G., Waythomas, C. F., and Neal, C. A., 1994, High stand and catastrophic draining of intracaldera Surprise Lake, Aniakchak volcano, Alaska: in Till, A. B. and Moore, T. E., (eds.), Geologic studies in Alaska by the U.S. Geological Survey, 1993, U.S. Geological Survey Bulletin B 2107, p. 59-71.
full-text PDF : 15 MB