Report on Karangetang (Indonesia) — 24 June-30 June 2015
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 24 June-30 June 2015
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2015. Report on Karangetang (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 24 June-30 June 2015. Smithsonian Institution and US Geological Survey.
2.781°N, 125.407°E; summit elev. 1797 m
All times are local (unless otherwise noted)
PVMBG reported that on 18 June a lahar in Karangetang’s Batuawang drainage (E) was 25 cm thick, carried boulders, and covered a 100-m section of roadway. The lahar also damaged or destroyed four homes. Based on observations conducted at the Karangetang Volcano Observation Post in the village of Salili, white plumes rose as high as 150 m above the main crater and 25 m above Crater II during 22-29 June. Incandescence from the lava dome was observed at night. Lava flowed from the S part of the dome; incandescent avalanches from the front the lava flow traveled as far as 2.3 km towards Batuawang and Kahetang drainages (E). Seismicity was dominated by signals characteristic of avalanches, and indicated that activity continued to be high. The Alert Level remained at 3 (on a scale of 1-4); visitors and residents were warned not to approach Karangetang within a 4-km radius.
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.