Report on Karangetang (Indonesia) — 30 March-5 April 2011
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 30 March-5 April 2011
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2011. Report on Karangetang (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 30 March-5 April 2011. Smithsonian Institution and US Geological Survey.
2.781°N, 125.407°E; summit elev. 1797 m
All times are local (unless otherwise noted)
CVGHM reported that during 30-31 March incandescence emanated from Karangetang's main crater as well as bluish and white gas plumes. Lava flows originating from the main crater traveled 2 km down the flanks. Incandescent avalanches from the main crater and from the lava-flow fronts traveled up to 1.8 km down the flanks. On 31 March a thunderous sound was accompanied by a gray plume that rose 200 m above the crater. The Alert Level remained at 3 (on a scale of 1-4).
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.