Report on Lokon-Empung (Indonesia) — 12 February-18 February 2003
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
12 February-18 February 2003
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2003. Report on Lokon-Empung (Indonesia). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 12 February-18 February 2003. Smithsonian Institution and US Geological Survey.
1.358°N, 124.792°E; summit elev. 1580 m
All times are local (unless otherwise noted)
On 10 February at 2219 an ash explosion occurred at Lokon-Empung, but the height of the resultant ash cloud could not be determined due to heavy rain. On 12 February, mainly during 0100-1000, there was a significant increase in volcanic earthquakes. At 1048 an explosion occurred, followed by seismic data indicating a larger explosion at 1102. On 12 February during 0800-1100 the Alert Level was raised from 3 to 4 (the highest level). Tremor was continuously recorded during 1255 on the 12th to 0046 the following day. According to the Darwin VAAC, an explosion occurred on 19 February at 0403 that produced a plume to 500 m above the summit.
Geological Summary. The Lokong-Empung volcanic complex, rising above the plain of Tondano in North Sulawesi, includes four peaks and an active crater. Lokon, the highest peak, has a flat craterless top. The morphologically younger Empung cone 2 km NE has a 400-m-wide, 150-m-deep crater that erupted last in the 18th century. A ridge extending 3 km WNW from Lokon includes the Tatawiran and Tetempangan peaks. All eruptions since 1829 have originated from Tompaluan, a 150 x 250 m crater in the saddle between Lokon and Empung. These eruptions have primarily produced small-to-moderate ash plumes that sometimes damaged croplands and houses, but lava-dome growth and pyroclastic flows have also occurred.