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Mount Westdahl

Westdahl

Stratovolcano · United States · 1563m

The summit area of Westdahl, located on the southwestern part of Unimak Island in the eastern Aleutians, is seen here from the east. Westdahl Peak (left) and Faris Peak (right) formed on the broad main edifice. The scoria cone in the center was the principal eruption site for the 1991-92 activity, producing the snow-covered lava flow in the foreground. . The sinuous fissure cutting across the glacial icecap from the summit formed in the opening phases of the eruption and produced lava fountaining.
The summit area of Westdahl, located on the southwestern part of Unimak Island in the eastern Aleutians, is seen here from the east. Westdahl Peak (left) and Faris Peak (right) formed on the broad main edifice. The scoria cone in the center was the principal eruption site for the 1991-92 activity, producing the snow-covered lava flow in the foreground. . The sinuous fissure cutting across the glacial icecap from the summit formed in the opening phases of the eruption and produced lava fountaining. · Photo: Photo by C.F. Zeillemaker, 1993 (U.S. Fish and Wildlife Service, courtesy of Alaska Volcano Observatory). · Wikimedia Commons
Type
Stratovolcano
Country
United States
Region
North America Volcanic Regions / Aleutian Ridge Volcanic Arc
Elevation
1563m
Coordinates
54.516, -164.650
Last eruption
1992
Tectonic setting
Subduction zone / Continental crust (> 25 km)
Landform
Composite
Major rock type
Basalt / Picro-Basalt
Geological summary

Westdahl is a broad 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 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, 6 km N, rises 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 may have originated instead from Westdahl (Miller et al. 1998). The first historical eruption occurred in 1795. An 8-km-long fissure extending east from the summit produced explosive eruptions and lava flows in 1991.

From Wikipedia

Westdahl Peak, also known as Westdahl Volcano or Mount Westdahl, is a stratovolcano of the Aleutian Range, in the U.S. state of Alaska. The volcano last erupted from November 29, 1991, to January 15, 1992.

Wikipedia · CC BY-SA · Read full article →

Eruption history

Summary (VEI over time)
Click a bar to see individual eruptions
1795~1815 · 2 eruptions · max VEI 41815~1834 · 2 eruptions · max VEI 21952~1971 · 1 eruptions · max VEI 21971~1991 · 3 eruptions · max VEI 317951834189319321971

Detailed timeline

  1. 1991VEI 3Observed
    1991-11-29 – 1992-01-14
    ENE flank (1560-760 m)
  2. 1979VEI 3Geological estimate
    1979-02-08 – 1979-02-09
  3. 1978VEI 3Observed
    1978-02-04 – 1978-02-09
    South of Westdahl Peak (1450 m)
  4. 1964VEI 2Observed
    1964-03-10 – 1964-04-16
  5. 1827VEI 2Observed
    1827 – 1830
    Pogromni or (more likely) Westdahl
  6. 1820VEI 2Observed
    1820 – Ongoing
    Pogromni or (more likely) Westdahl
  7. 1796VEI 0Observed
    1796 – Ongoing
    Pogromni or (more likely) Westdahl
  8. 1795VEI 4Observed
    1795 – Ongoing
    Pogromni or (more likely) Westdahl

External links

⚠ For reference only. Not for emergency response.