Report on Karangetang (Indonesia) — February 1985
Scientific Event Alert Network Bulletin, vol. 10, no. 2 (February 1985)
Managing Editor: Lindsay McClelland.
Karangetang (Indonesia) Lava flow from S flank vent
Please cite this report as:
Global Volcanism Program, 1985. Report on Karangetang (Indonesia). In: McClelland, L. (ed.), Scientific Event Alert Network Bulletin, 10:2. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198502-267020.
2.781°N, 125.407°E; summit elev. 1797 m
All times are local (unless otherwise noted)
A 4-day eruption began 24 February. Effusive material was erupted from a S flank new vent, about 300-400 m from the main crater. A lava flow extended ~350 m S (along the Batuawang River), stopping after four days. Inhabitants downslope of the lava flow were alerted, including the villages of Kola, Bola, and Kopi. Harmonic tremor indicated lava movement a few hours before effusive activity began, but no other significant changes in seismicity were detected during the activity.
Api Siau has been the site of nearly continuous activity for the last 20 years.
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.
Information Contacts: A. Sudradjat, VSI.