Report on Lokon-Empung (Indonesia) — 3 October-9 October 2012
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 3 October-9 October 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, 3 October-9 October 2012. 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 the Darwin VAAC, CVGHM reported that on 6 October an ash plume from Lokon-Empung rose to an altitude of 3.7 km (12,000 ft) a.s.l.; the plume altitude was determined by wind data. A thermal anomaly was detected in satellite imagery. According to a news article, an eruption at 1405 on 7 October ejected incandescent tephra as high as 350 m above the crater and generated an ash plume that rose 1.5 km. The article also noted that Lokon-Empung had erupted 41 times in September and three times on 5 October.
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.