Report on Lokon-Empung (Indonesia) — 18 April-24 April 2012
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 18 April-24 April 2012
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2012. Report on Lokon-Empung (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 18 April-24 April 2012. Smithsonian Institution and US Geological Survey.
1.358°N, 124.792°E; summit elev. 1580 m
All times are local (unless otherwise noted)
CVGHM reported that during the morning on 24 April diffuse white plumes rose 25-50 m above Tompaluan crater, in the saddle between the Lokon-Empung peaks. Later that day an eruption was accompanied by loud "thumping" noises heard at local observation posts, though fog prevented views of the crater. The next day diffuse white plumes rose 50-100 m above the crater. The Alert Level remained at 3 (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.