Report on Karangetang (Indonesia) — 5 March-11 March 2003
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 5 March-11 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, 5 March-11 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 24 February to 2 March, volcanic activity at Karangetang's South crater consisted of "white-gray ash emissions" rising to low levels, incandescent glow extending to 50 m above the crater, and a booming noise that was heard from the observatory post. During the report period, there was an increase in the number of shallow volcanic earthquakes, while the number of multiphase earthquakes decreased. Karangetang remained at Alert Level 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.