Report on Karangetang (Indonesia) — 9 March-15 March 2011
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 9 March-15 March 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, 9 March-15 March 2011. Smithsonian Institution and US Geological Survey.
2.781°N, 125.407°E; summit elev. 1797 m
All times are local (unless otherwise noted)
Based on analyses of satellite imagery, the Darwin VAAC reported that on 11 March an ash plume from Karangetang rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 55 km SW. According to news reports, lava flows at the summit were visible on 11 March. Blocks originating from the lava dome traveled as far as 2 km down the flanks. Hot gas clouds also descended the flanks. The VAAC also noted that on 13 March an ash plume rose to an altitude of 3.7 km (12,000 ft) a.s.l. and drifted 37 km.
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.