Report on Lokon-Empung (Indonesia) — 2 April-8 April 2003
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
2 April-8 April 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, 2 April-8 April 2003. Smithsonian Institution and US Geological Survey.
1.358°N, 124.792°E; summit elev. 1580 m
All times are local (unless otherwise noted)
Beginning on 31 March the number of volcanic earthquakes at Lokon-Empung was relatively high. On 1 April at 2242 an explosion produced an ash column to a height of ~1.5 km over the crater. Ash drifted SSE and accumulated as an up to 1-mm-thick layer in the town of Tomohon. Incandescent material was hurled to ~350 m high and cascaded around the crater. Through 0900 on 3 April tremor earthquakes continued to be recorded. Lokon-Empung remained at Alert Level 2 (on a scale of 1-4).
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.