Report on Lokon-Empung (Indonesia) — 17 April-23 April 2002
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 17 April-23 April 2002
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2002. Report on Lokon-Empung (Indonesia). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 17 April-23 April 2002. Smithsonian Institution and US Geological Survey.
1.358°N, 124.792°E; summit elev. 1580 m
All times are local (unless otherwise noted)
Increases in volcanic and seismic activity at Lokon-Empung led VSI to raise the Alert Level from 2 to 3 (on a scale of 1-4) on 12 April. Eruptions occurred on 10 April at 2302 and on the 12th at 1816. On 13 April eight gas-and-ash explosions occurred and on the 14th five occurred. Tremor that began on 11 April continued through at least the 14th.
Geologic Background. The twin volcanoes Lokon and Empung, rising about 800 m above the plain of Tondano, are among the most active volcanoes of Sulawesi. Lokon, the higher of the two peaks (whose summits are only 2 km apart), has a flat, craterless top. The morphologically younger Empung volcano to the NE has a 400-m-wide, 150-m-deep crater that erupted last in the 18th century, but all subsequent eruptions have originated from Tompaluan, a 150 x 250 m wide double crater situated in the saddle between the two peaks. Historical eruptions have primarily produced small-to-moderate ash plumes that have occasionally damaged croplands and houses, but lava-dome growth and pyroclastic flows have also occurred. A ridge extending WNW from Lokon includes Tatawiran and Tetempangan peak, 3 km away.