Report on Lokon-Empung (Indonesia) — June 1991
Bulletin of the Global Volcanism Network, vol. 16, no. 6 (June 1991)
Managing Editor: Lindsay McClelland.
Lokon-Empung (Indonesia) Explosions eject small ash columns
Please cite this report as:
Global Volcanism Program, 1991. Report on Lokon-Empung (Indonesia) (McClelland, L., ed.). Bulletin of the Global Volcanism Network, 16:6. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199106-266100.
1.358°N, 124.792°E; summit elev. 1580 m
All times are local (unless otherwise noted)
Ash explosions occurred at 1537 on 27 May and 1000 on 28 May, producing columns 250 m high. Continued ash explosions were observed at a rate of 7-16/week, with column heights of 200-400 m. Seismic activity was characterized by explosion earthquakes, averaging 30-50 recorded events/week. Shallow and deep volcanic earthquakes were less frequent (2-8 and 3-9 events/week, respectively). Tectonic earthquakes ranged from 18 to 101 weekly.
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: W. Modjo, VSI.