Report on Karangetang (Indonesia) — 19 September-25 September 2001
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 19 September-25 September 2001
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2001. Report on Karangetang (Indonesia). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 19 September-25 September 2001. 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 September fewer lava flows and lava avalanches traveled down the flanks of Karangetang than in the previous week. Lava flowed down the Kahetang and Keting rivers as far as 1.5 km, and one-km-long avalanches developed at the ends of these flows. Seismicity was dominated by small explosion and multiphase earthquakes. Emissions of steam and possibly ash at the northern main crater rose to 0.5 km. The volcano 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.