Geologic Background:
Mount Spurr, the highest volcano of the Aleutian
arc, is a large lava dome at the center of a ~5-km-wide
horseshoe-shaped caldera that opens to the S. The caldera
was formed by a late Pleistocene or early Holocene debris
avalanche that destroyed an ancestral Spurr volcano. The
Spurr volcanic complex consists of an older volcano which
collapsed and the present day Mount Spurr and Crater
Peak.
Historic Activity:
- Crater Peak was the location of the first major
historic eruption at Spurr, on July 9, 1953.
Recent Activity:
- During early 1992, seismic activity was at the
highest levels since the start of monitoring in 1980.
Volcanic tremor began on June 26, 1992 with moderate
explosive eruptive activity beginning the next day. The
eruption sent ash to about 8 km altitude. A second brief
explosive eruption occurred on August 18, 1992 and sent a
plume to almost 11 km altitude. A third explosive
eruption from Crater Peak occurred during the night of
Sept. 16-17, 1992. The plume reached a maximum altitude
of 15 km. Mudflows and hot pyroclastic avalanches were
also reported. Seismicity continued into early 1993.
Data Sources:
- Global Volcanism Network (V. 17, No. 3 to V. 23, No.
3).
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