Report on Lokon-Empung (Indonesia) — March 1986
Scientific Event Alert Network Bulletin, vol. 11, no. 3 (March 1986)
Managing Editor: Lindsay McClelland.
Lokon-Empung (Indonesia) Explosions empty crater lake; mud flows
Please cite this report as:
Global Volcanism Program, 1986. Report on Lokon-Empung (Indonesia). In: McClelland, L (ed.), Scientific Event Alert Network Bulletin, 11:3. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198603-266100.
1.358°N, 124.792°E; summit elev. 1580 m
All times are local (unless otherwise noted)
"Activity began 22 March at 0336 with a small phreatic eruption from the Tompaluan Crater . . . . A small (700,000 m3) crater lake within Tompaluan crater was ~60% evacuated during the 22 March eruption. A larger, phreatomagmatic eruption occurred on 24 March at 0343, emptying the remainder of the lake and throwing out incandescent ballistic blocks to heights of 800-1,000 m. Mudflows were produced during both eruptions. No casualties or damage have been reported. Small explosions occurred on 29 March at 1547 to 250 m height, at 1806 to 300 m, and at 1817 to 200 m. The VSI observation post is located at Kakaskasen, ~5 km SE of the volcano. The observatory has one vertical component seismometer, located at Lokon."
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: Suratman, A. Sudradjat and T. Casadevall, VSI.