Report on Lokon-Empung (Indonesia) — January 1996
Bulletin of the Global Volcanism Network, vol. 21, no. 1 (January 1996)
Managing Editor: Richard Wunderman.
Lokon-Empung (Indonesia) Variable seismicity and minor vapor emissions
Please cite this report as:
Global Volcanism Program, 1996. Report on Lokon-Empung (Indonesia). In: Wunderman, R. (ed.), Bulletin of the Global Volcanism Network, 21:1. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199601-266100.
1.358°N, 124.792°E; summit elev. 1580 m
All times are local (unless otherwise noted)
Vapor emission was observed during November-December 1995 and whitish-gray plumes rose to 100 m above the active crater. Seismicity during September-October 1995 consisted of 1- 8 A-type events/day. On 1 November there were 46 A-type events recorded, followed by very low seismicity over the next ten days. Activity then increased from 12 November through 31 December, but was highly variable with 4-21 events/day. B-type events remained at 0-8 events/day.
The present activity is located at Tompaluan crater, in the saddle between the peaks of Lokon (1,579 m) and Empung (1,340 m). About 10,000 people evacuated following an explosion in October 1991 accompanied by a pyroclastic flow; the eruption ended in January 1992.
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.
Information Contacts: Wimpy S. Tjetjep (Director), Volcanological Survey of Indonesia (VSI), Jalan Diponegoro 57, Bandung, Indonesia.