Geologic Background:
Umboi Island, 50 km in its longest dimension, is
the largest of the volcanic islands off the north coast
of New Guinea. Umboi is comprised of several coalescing
stratovolcanoes that are cut by a large 13 x 17 km
caldera whose walls rise up to 1 km above its floor. The
caldera is widely breached to the sea on the NE side and
contains three youthful post-caldera cones with summit
crater lakes, Talo, Soal, and Barik. The largest of these
cones, Talo, displays several thermal areas. No
historical eruptions have been reported at Umboi, but
activity of the post-caldera cones is thought to have
continued until the last few hundred years.
Historic Activity:
Recent Activity:
- Seismic activity during August and September
1985.
Data Sources:
- Smithsonian's SEAN Bulletin (V. 10, No. 9).
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