GEOLOGIC HISTORY
The relatively small Kelut stratovolcano contains a
summit crater lake that has been the source of some of
Indonesia's most deadly eruptions. A cluster of summit lava
domes cut by numerous craters has given the summit a very
irregular profile. Satellitic cones and lava domes are also
located low on the eastern, western, and SSW flanks.
Eruptive activity has in general migrated in a clockwise
direction around the summit vent complex.
Historic Activity:
- More than 30 eruptions have been recorded from Gunung
Kelut since 1000 AD. The ejection of water from the
crater lake during Kelut's typically short, but violent
eruptions has created pyroclastic flows and lahars that
have caused widespread fatalities and destruction. The
construction of drainage tunnels beginning in 1926 to
lower the lake level has greatly reduced the human impact
of recent eruptions.
- After lahars and pyroclastic flows from the 1919
eruption killed more than 5,000 people, an ambitious
engineering project sought to drain the crater lake.
- This initial effort lowered the lake by more than 50
m, but the 1951 eruption deepened the crater by 70 m,
leaving 50 million cubic meters of water after repair of
the damaged drainage tunnels. After more than 200 deaths
in the 1966 eruption, a new deeper tunnel was
constructed, and the lake's volume before the 1990
eruption was only about 1 million cubic meters.
Recent Activity:
- A strong explosive eruption on Feb. 10, 1990 produced
a 7-km column of tephra, heavy tephra falls, several
pyroclastic flows, and more than 30 people were killed.
Workers continued to quarry the still-hot (90-400°C)
pyroclastic-flow deposits (about 25 m thick) that buried
the mouth of the Ampera Tunnel, in the SW side of the
crater. The tunnel was constructed to drain the crater
lake after the 1966 eruption, and thus to reduce the
lahar hazard.
- Increasing water temperatures in January 2001.
Data Sources
- Global Volcanism Network (V. 15, No. 1 to V. 26, No.
1).
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