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Report on Lokon-Empung (Indonesia) — July 2002

Bulletin of the Global Volcanism Network, vol. 27, no. 7 (July 2002)
Managing Editor: Richard Wunderman.

Lokon-Empung (Indonesia) Increased activity; gas plumes with occassional ash emitted during June and July 2002

Please cite this report as:

Global Volcanism Program, 2002. Report on Lokon-Empung (Indonesia). In: Wunderman, R. (ed.), Bulletin of the Global Volcanism Network, 27:7. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN200207-266100.

Volcano Profile |  Complete Bulletin


Lokon-Empung

Indonesia

1.358°N, 124.792°E; summit elev. 1580 m

All times are local (unless otherwise noted)


During 27 May-4 August 2002, activity was higher than normal at Lokon. Volcanic and tectonic earthquakes dominated the seismicity (table 3). Generally thin white plumes, reported as "ash plumes" after 1 July, were reaching 25-150 m above the crater rim. Tremor amplitude was 0.5-1 mm during 27 May-2 June. The Alert Level was decreased from 3 to 2 during early June and remained at 2 throughout the report period.

Table 3. Earthquakes occurring at Lokon during 3 June-4 August 2002. Courtesy VSI.

Date Deep volcanic (A-type) Shallow volcanic (B-type) Tectonic
03 Jun-09 Jun 2002 18 35 32
10 Jun-16 Jun 2002 19 30 29
17 Jun-23 Jun 2002 5 30 37
24 Jun-30 Jun 2002 14 35 23
01 Jul-07 Jul 2002 24 93 30
08 Jul-14 Jul 2002 49 111 31
15 Jul-21 Jul 2002 7 24 26
22 Jul-28 Jul 2002 19 22 41
29 Jul-04 Aug 2002 8 38 27

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: Dali Ahmad, Volcanological Survey of Indonesia (VSI), Jalan Diponegoro No. 57, Bandung 40122, Indonesia (URL: http://www.vsi.esdm.go.id/).