Report on Karangetang (Indonesia) — 19 July-25 July 2006
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 19 July-25 July 2006
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2006. Report on Karangetang (Indonesia) (Sennert, S, ed.). Weekly Volcanic Activity Report, 19 July-25 July 2006. Smithsonian Institution and US Geological Survey.
2.781°N, 125.407°E; summit elev. 1797 m
All times are local (unless otherwise noted)
The Alert Status of Karangetang was raised on 22 July from 3 to 4 (on a scale of 1-4) due to a further increase in eruptive activity since the last reporting period. On 20 July, lava flows were observed moving E toward the Kahetang and Batu Awang rivers at a maximum distance of 1.8 km from the vent, towards the Keting river at unknown location and distance, and S towards the Bahembang river at a maximum distance of 2 km. On 21 July, a pyroclastic flow originating from the upper S flank traveled 2.5 km toward the Stone river (unknown direction) and was followed by lava flows that traveled toward the Keting river and E towards the Kahetang river at a maximum distance of 2 km. A "thin white smoke" was seen at a height of ~350 m above the summit (7,000 ft a.s.l.). Lava flows traveled a maximum distance of ~2.3 km towards the Keting river and S towards the Bahembang river during 22-23 and 25 July.
Geological Summary. Karangetang (Api Siau) volcano lies at the northern end of the island of Siau, about 125 km NNE of the NE-most point of Sulawesi. The stratovolcano contains five summit craters along a N-S line. It is one of Indonesia's most active volcanoes, with more than 40 eruptions recorded since 1675 and many additional small eruptions that were not documented (Neumann van Padang, 1951). Twentieth-century eruptions have included frequent explosive activity sometimes accompanied by pyroclastic flows and lahars. Lava dome growth has occurred in the summit craters; collapse of lava flow fronts have produced pyroclastic flows.