Geologic Background:
The Ukinrek Maars formed 30 March-10 April, 1977
as a result of magmatic intrusion into water-saturated
glacial till 2 km S of Gas Rocks on the S shore of Lake
Becharof. There were no major seismic events detected in
association with the 1977 Ukinrek Maars eruptions, except
for a number of small events detected by a portable
seismic net which was deployed for several months
following the 1977 eruptions. During a 10-day period,
violent explosions produced steam and ash plumes as high
as 6.5 km and light ash fall as far as 160 km to the N.
Since the Ukinrek Maars formed, CO2 gas has been
continuously emitted from the vicinity of the maars, the
Gas Rocks, and from beneath Lake Becharof.
Historic Activity:
- First activity was in 1977.
Recent Activity
- Seismic swarm in area in May 1998.
Data Sources:
- Global Volcanism Network (V. 23, No. 4 and 5)
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