Report on Karangetang (Indonesia) — 29 April-5 May 2015
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 29 April-5 May 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, 29 April-5 May 2015. 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 observations conducted at the Karangetang Volcano Observation Post in the village of Salili, PVMBG reported that white plumes rose as high as 350 m above Karangetang's main crater and 25 m above Crater II during 22-29 April. Incandescence from the lava dome was observed at night. Lava flows began to appear on 22 April; incandescent avalanches from the fronts of 150-m-long lava flows traveled as far as 2 km towards Batuawang and Kahetang drainages (E) during 22-29 April. On 26 April pyroclastic flows traveled 2.2 km towards Kahetang drainage. On 28 April explosions produced plumes and ejected incandescent material 50 m high. The Alert Level remained at 3 (on a scale of 1-4); visitors and residents were warned not to climb Karangetang any higher than 500 a.s.l.
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.