Report on Karangetang (Indonesia) — 16 October-22 October 2002
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 16 October-22 October 2002
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2002. Report on Karangetang (Indonesia). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 16 October-22 October 2002. Smithsonian Institution and US Geological Survey.
2.781°N, 125.407°E; summit elev. 1797 m
All times are local (unless otherwise noted)
During 7-14 October, VSI raised the Alert Level at Karangetang from 2 to 3. During this period, a thick ash plume rose ~400 m above South Crater and incandescent lava avalanches traveled ~250 m toward Nanitu River and ~400 m W toward Beha River. Also, a thin ash plume rose ~50 m above North Crater. On 19 October at 1759 an explosion produced an ash cloud to ~750 m above the volcano. The ash cloud drifted N, depositing ash into the sea. In addition, glowing material was ejected 500 m vertically and landed inside the crater. During 14-21 October, lava avalanches continued to travel down Karangetang's flanks and lava flowed 1,500 m toward Nanitu River, 1,000 m toward Beha River, and 750 m E toward Kahetang River.
Geologic Background. 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 island. 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 in the historical record (Catalog of Active Volcanoes of the World: 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.