Report on Karangetang (Indonesia) — 19 March-25 March 2003
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 19 March-25 March 2003
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2003. Report on Karangetang (Indonesia). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 19 March-25 March 2003. Smithsonian Institution and US Geological Survey.
2.781°N, 125.407°E; summit elev. 1797 m
All times are local (unless otherwise noted)
During 10-16 March, Karangetang's South crater generated low-level "white-gray ash emissions" and incandescence visible to 50 m above the crater. Incandescent lava avalanches traveled toward Kahetang, Batuawang, Batang, and Beha rivers. During the report period, there was a decrease in the number of earthquakes, and seismicity was dominated by 125 avalanche earthquakes. The Alert Level at Karangetang 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, north 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 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 has also produced pyroclastic flows.