Geologic Background:
Irruputuncu is a small stratovolcano that
straddles the Chile/Bolivia border. It is the youngest
and most southerly of a NE-SW-trending chain of
volcanoes. Irruputuncu was constructed within the
collapse scarp of a Holocene debris avalanche whose
deposit extends to the SW. Subsequent eruptions filled
much of this scarp and produced thick, viscous lava flows
down the western flank. The summit complex contains two
craters, the southernmost of which is fumarolically
active.
Historic Activity:
- No clear documentation of any historical Irruputuncu
eruptions.
Recent Activity:
- The first unambiguous historical eruption from
Irruputuncu took place in November 1995, when phreatic
explosions produced dark ash clouds. Report of dark,
vertical plume on Nov. 26, 1995. Plume alternated between
dark gray, black, and white and reached a few kilometers
above Irruputuncu. The observations suggested that the
activity consisted of modest phreatic eruptions.
Data Sources:
- Global Volcanism Network (V. 15, No. 3 and V. 22, No.
1).
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