No latest activity reported for Westdahl.

Below is a summary of eruption dates and Volcanic Explosivity Indices (VEI).

The following references are the sources used for data regarding this volcano. References are linked directly to our volcano data file. Discussion of another volcano or eruption (sometimes far from the one that is the subject of the manuscript) may produce a citation that is not at all apparent from the title. Additional discussion of data sources can be found under Volcano Data Criteria.

Coats R R, 1950. Volcanic activity in the Aleutian Arc. {U S Geol Surv Bull}, 974-B: 35-47

IAVCEI, 1973-80. Post-Miocene Volcanoes of the World. {IAVCEI Data Sheets, Rome: Internatl Assoc Volc Chemistry Earth's Interior}.

Lamb H H, 1970. Volcanic dust in the atmosphere; with a chronology and assessment of its meteorological significance. {Phil Trans Roy Soc London}, Ser A, 266: 425-533

Miller T P, McGimsey R G, Richter D H, Riehle J R, Nye C J, Yount M E, Dumoulin J A, 1998. Catalogue of the historically active volcanoes of Alaska. {U S Geol Surv Open-File Rpt}, 98-582: 1-104

Motyka R J, Liss S A, Nye C J, Moorman M A, 1993. Geothermal resources of the Aleutian arc. {Alaska Div Geol Geophys Surv, Prof Rpt}, no 114, 17 p and 4 map sheets

Myers J D, 1994. {The Geology, Geochemistry and Petrology of the recent Magmatic Phase of the Central and Western Aleutian Arc}. {Unpublished manuscript}, unpaginated

Smith R L, Shaw H R, Luedke R G, Russell S L, 1978. Comprehensive tables giving physical data and thermal energy estimates for young igneous systems of the United States. {U S Geol Surv Open-File Rpt}, 78-925: 1-25

Wood C A, Kienle J (eds), 1990. {Volcanoes of North America}. Cambridge, England: Cambridge Univ Press, 354 p

Westdahl is a broad, 1654-m-high glacier-covered volcano occupying the SW end of Unimak Island. Two peaks protrude from the summit plateau, and a new crater formed in 1978 cuts the summit icecap. The broad volcano has a somewhat of a shield-like morphology and forms one of the largest volcanoes of the Aleutian Islands. The sharp-topped, conical Pogromni stratovolcano lies 5 km north of Westdahl. Pogromni rises to 2002 m, several hundred meters higher than Westdahl, but is moderately glacially dissected and presumably older. Many satellitic cones of postglacial age are located along a NW-SE line cutting across the summit of Westdahl. Some of the historical eruptions attributed to the eroded Pogromni volcano may have originated instead from Westdahl (Miller et al. 1998). The first historical eruption of Westdahl occurred in 1795. An 8-km-long fissure extending east from the summit of Westdahl produced explosive eruptions and lava flows in 1991.