Report on Kelut (Indonesia) — 26 September-2 October 2007
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 26 September-2 October 2007
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2007. Report on Kelut (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 26 September-2 October 2007. Smithsonian Institution and US Geological Survey.
7.93°S, 112.308°E; summit elev. 1731 m
All times are local (unless otherwise noted)
CVGHM reported that the Alert Status of Kelut was raised on 29 September from 2 to 3 (on a scale of 1-4) based on observations, increased seismic activity, deformation measurements, and changes of crater lake water chemistry and temperature. Villagers and tourists were advised not go within a 5 km radius of the active crater.
Geologic Background. The relatively inconspicuous 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 E, W, and SSW flanks. Eruptive activity has in general migrated in a clockwise direction around the summit vent complex. More than 30 eruptions have been recorded from Gunung Kelut since 1000 CE. The ejection of water from the crater lake during the typically short but violent eruptions has created pyroclastic flows and lahars that have caused widespread fatalities and destruction. After more than 5000 people were killed during an eruption in 1919, 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.