Report on Karangetang (Indonesia) — January 2010
Bulletin of the Global Volcanism Network, vol. 35, no. 1 (January 2010)
Managing Editor: Richard Wunderman.
Karangetang (Indonesia) Lava flows and pyroclastic flows seen during 2009
Please cite this report as:
Global Volcanism Program, 2010. Report on Karangetang (Indonesia). In: Wunderman, R. (ed.), Bulletin of the Global Volcanism Network, 35:1. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN201001-267020.
2.781°N, 125.407°E; summit elev. 1797 m
All times are local (unless otherwise noted)
At Karangetang during May 2009, emissions included explosions and lava flows (BGVN 34:05). Activity continued during June and into at least early 2010.
During the first week of June 2009, lava flows from Karangetang traveled 50 m E and 600 m SE. According to the Center of Volcanology and Geological Hazard Mitigation (CVGHM), incandescent rocks from the main craters and ends of the lava flow traveled as far as 2 km towards multiple river valleys, including the Keting River to the S. On 1 June, white-to-gray-to-brown plumes rose 700 m above the main crater. Incandescent lava was ejected 500-700 m. On 4 June, both the tremor amplitude and the number of earthquakes decreased. During 4-6 June, white plumes rose 50-300 m from the main crater. On 7 and 8 June, fog often prevented observations and incandescent rocks were rarely seen. The Alert Level was lowered to 3 (on a scale of 1-4) on 9 June.
No further activity was reported until 3 November 2009. Based on a pilot observation and satellite imagery, the Darwin Volcanic Ash Advisory Centre (VAAC) reported that on 3 November an ash plume rose to an altitude of 3 km and drifted 90-185 km W.
According to news reports, a pyroclastic flow and a lahar descended the flanks on 4 November. Residents saw active lava flows the next day. On 11 November, incandescent material was ejected 5 m into the air.
CVGHM noted that seismicity declined during 1 January-8 February 2010. When the weather was clear, white plumes were seen rising 100-200 m above the crater rim. Incandescent material was ejected 10-50 m above the Utama Crater. CVGHM lowered the Alert Level to 2 on 12 February.
MODVOLC. MODVOLC thermal alerts that were previously reported in March through 3 June 2009 (BGVN 34:05) continued through 8 November. Alerts were recorded on 10 July, 5 September, 5 October, 16 October, 30 October, 3 November (4 pixels on Aqua, 4 pixels on Terra), 4 November (2 pixels on Terra, 1 pixel on Aqua), and 8 November. No alerts were recorded between 8 November 2009 and 19 February 2010.
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: Center of Volcanology and Geological Hazard Mitigation (CVGHM), Jalan Diponegoro 57, Bandung 40122, Indonesia (URL: http://vsi.esdm.go.id/); Hawai'i Institute of Geophysics and Planetology (HIGP) Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); Darwin Volcanic Ash Advisory Centre (VAAC), Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, NT 0811, Australia (URL: http://www.bom.gov.au/info/vaac/); Berita News (URL: http://berita.liputan6.com/).