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  • Country
  • Subregion Name
  • Primary Volcano Type
  • Last Known Eruption
  • 54.518°N
  • 164.65°W

  • 1654 m
    5425 ft

  • 311340
  • Latitude
  • Longitude

  • Summit

  • Volcano

There are no activity reports for Westdahl.

 Available Weekly Reports

There are no Weekly Reports available for Westdahl.

Summary of eruption dates and Volcanic Explosivity Indices (VEI).

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
1991 Nov 29 1992 Jan 14 Confirmed 3 Historical Observations ENE flank (1560-760 m)
[ 1979 Feb 8 ] [ 1979 Feb 9 ] Uncertain 3  
1978 Feb 4 1978 Feb 9 Confirmed 3 Historical Observations South of Westdahl Peak (1450 m)
1964 Mar 10 1964 Apr 16 Confirmed 2 Historical Observations
1827 1830 Confirmed 2 Historical Observations Pogromni or (more likely) Westdahl
1820 Unknown Confirmed 2 Historical Observations Pogromni or (more likely) Westdahl
1796 Unknown Confirmed 0 Historical Observations Pogromni or (more likely) Westdahl
1795 Unknown Confirmed 4 Historical Observations Pogromni or (more likely) Westdahl

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 Unpublished manuscript, unpaginated.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.