Report on Lokon-Empung (Indonesia) — 21 December-27 December 2011
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 21 December-27 December 2011
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2011. Report on Lokon-Empung (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 21 December-27 December 2011. Smithsonian Institution and US Geological Survey.
1.358°N, 124.792°E; summit elev. 1580 m
All times are local (unless otherwise noted)
According to a news article, three explosions from the Tompaluan crater, in the saddle between the Lokon-Empung peaks were recorded by the CVGHM on 27 December. CVGHM recorded 23 deep volcanic tremors and 40 shallow volcanic tremors. Residents and tourists were not permitted within a 2.5 km radius of the crater. Based on visual and seismic observations during 27-28 December, the Alert Level remained at 3 (on a scale of 1-4). The Darwin VAAC reported a low-level eruption on 27 December based on media reports.
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.