Report on Lokon-Empung (Indonesia) — 5 February-11 February 2003
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
5 February-11 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, 5 February-11 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)
Starting at the beginning of the report week (3-9 February), there was an increase in seismicity and surface activity at Lokon-Empung in comparison to the previous week. There were more emission, and deep and shallow volcanic earthquakes and ash emissions. On 8 February at 0443 an ash explosion was accompanied by the ejection of incandescent volcanic material. A thick ash cloud rose to 1.4 km over the crater and 0.5-1 mm of ash was deposited S of the volcano in the villages of Kayau, Tara-tara I and II, and Woloan II and III. At this time the Alert Level was raised from 2 to 3 (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.