Report on Lokon-Empung (Indonesia) — 14 November-20 November 2001
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 14 November-20 November 2001
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2001. Report on Lokon-Empung (Indonesia). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 14 November-20 November 2001. Smithsonian Institution and US Geological Survey.
1.358°N, 124.792°E; summit elev. 1580 m
All times are local (unless otherwise noted)
Following a tectonic earthquake near Lokon on 19 October, activity increased at the volcano; high-frequency tremor occurred and gray emissions rose 50-250 m above Tompaluan crater. While fewer earthquakes were recorded during 12-18 November (10 per day) in comparison to the previous week (19 per day), the number of earthquakes was still above normal levels. No major changes in volcanic activity were seen at Lokon's summit. The Alert Level at Lokon remained at 2 (on a scale of 1-4).
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.