Geologic Background:
The largest volcanic center in the central
Aleutians, Atka consists of a central shield and caldera
ringed by 7 or 8 satellitic volcanoes. The most prominent
of these are the Holocene cones of Sarichef, Kliuchev,
Korovin, and Konia, some of which have been active in
historical time. Korovin, the most frequently active
volcano of the Atka volcanic center, contains a
1533-m-high double summit and an unusual, open
cylindrical vent of widely variable depth that
periodically contains a crater lake or a high magma
column.
Historic Activity:
- Eruptions on Korovin occurred in 1829?, 1830?, 1844?,
1907, 1951, and 1974.
Recent Activity:
- In May 1986 small steam and ash plumes were
observed.
- In March 1987 steam and ash plumes were again
observed.
- On December 4, 1993, following a magnitude 5.1
earthquake, rumblings were reported from the cluster of
volcanoes that forms the north part of the island of
Atka. Residents also reported increased steaming from a
fumarolic area on the flank of Kliuchef volcano, and a
distinct sulphur smell.
- Reports of very strong sulfur smell and small
plume-like cloud in early May 1995.
- Eruption of volcanic ash reported in June 1996.
- Eruption of volcanic ash reported in June 1998
Data Sources:
- Smithsonian's SEAN Bulletin (V. 11, No. 5 and V. 12,
No. 3)
- Global Volcanism Network (V. 18, No. 11 and V. 23,
No. 6).
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