New ash explosion with plume reaching 3 km – Lokon volcano, Indonesia

Another ash explosion with plume rising up to 3 km occurred at 12:10 local time today, December 11, 2012 followed by a smaller one at 12:41 and 13:16 local time on active Indonesian volcano Lokon.

The first explosion was relatively violent and produced a plume rising approx. 3000 m visible from Manado city 15 km to the north and the explosion sound caused people in nearby Tomohon to run out on the streets. The following 2 explosions were much smaller and produced plumes only a few 100 m in height. Volcanologists stationed in Kakaskasen said that volcanic tremor was recorded almost continuously.

Small to medium-sized explosive ash eruptions continue to occur every 1-3 days (such as on 3, 6, 7 and 9 December). Ash plumes observed from ground and by satellite reached estimated 10-17,000 ft (3-5 km) altitude. (VolcanoDiscovery)

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 2.2 km apart), has a flat, craterless top. The morphologically younger Empung volcano 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 (GVP).

Featured image: Photo by Agus Solihin, 1998 (Volcanological Survey of Indonesia).