Higher-than-normal activity continued at Lokon-Empung during August-December 2002. Throughout the report period a "white-thin ash plume" rose 25-75 m above the crater rim. No ashfall was reported. Seismicity was dominated by shallow volcanic and tectonic earthquakes (table 4).

Table 4. Earthquakes recorded at Lokon during 5 August-29 December 2002. No reports were issued during 11 November-22 December. Courtesy VSI.

During the week of 4-10 November, the hazard status was reduced from Alert Level 2 to 1 (on a scale of 1-4). On 23 December a "white-thick ash plume" rose 100-250 m over Tompaluan crater. No ashfall was reported. [A later report did note ashfall.] The same day, volcanic tremor with an amplitude of 0.5-2 mm occurred. A total of 42 emissions were reported during 23-29 December. The Alert Level returned to 2 by the end of the report period.

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.

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