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Report on Soputan (Indonesia) — April 2012


Bulletin of the Global Volcanism Network, vol. 37, no. 4 (April 2012)
Managing Editor: Richard Wunderman.

Soputan (Indonesia) Alert level raised in May 2012 based on increased seismic activity

Please cite this report as:

Global Volcanism Program, 2012. Report on Soputan (Indonesia) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 37:4. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN201204-266030



1.112°N, 124.737°E; summit elev. 1785 m

All times are local (unless otherwise noted)

Our previous report of Soputan volcano chronicled activity during July-September 2011 (BGVN 36:11). Table 9 gives a brief history of activity and highlights activity through early May 2012. The data sources are the Darwin Volcanic Ash Advisory Centre (VAAC) for satellite monitoring of ash plumes and the Indonesian Center of Volcanology and Geological Hazard Mitigation (CVGHM) for seismic monitoring and assignment of alert levels. According to a 28 May 2012 report by CVGHM, Soputan's activities are characterized by the growth of lava domes that have been accreting steadily since 1991. The accretion of these lava domes has been frequently accompanied by ash/cinder eruptions.

Table 9. Summary of volcanic ash observations and other activity at Soputan volcano from late June 2011 through mid-2012. 'VA' refers to volcanic ash. Courtesy of Darwin VAAC and CVGHM.

Date Observations Remarks
21 Jun-02 Jul 2011 Seismic activity increased --
02 Jul 2011 -- Alert Level 2 to 3
03 Jul-04 Jul 2011 Explosive eruption of incandescent material with pyroclastic flow 4 km to W; VA plume to 4.6-14 km extending 407 km W --
04 Jul 2011 High-level eruption has ceased, dissipating --
19 Jul 2011 -- Alert Level 3 to 2
14 Aug 2011 Two eruptions; VA plume to 3.7 km extending 107 km W Alert Level 2 to 3; VA not identifiable on satellite imagery
14 Aug-07 Sep 2011 Seismic Activity significantly decreased after eruption --
08 Sep 2011 Hot air blasts of smoke from the mass of the lava dome Alert Level 3 to 2
28 May 2012 Seismic activity significantly increased Alert Level 2 to 3

On 28 May 2012, CVGHM raised the Alert Level of Soputan from 2 to 3 (on a scale of 1-4) following increasing sesimic activity. According to CVGHM, increasing activity had been observed from 21-27 May, when the volcano spewed out white smoke to heights of between 50 to 150 m above the summit. Seismicity increased significantly on 25 May.

CVGHM called on local residents to stay beyond a 6 km radius from the volcano's summit. It also warned residents of the threat of a lahar, urging people living near Ranowangko, Pentu, Lawian and Popang rivers to remain alert and aware.

MODVOLC Thermal Alerts. MODVOLC satellite thermal alerts were measured at Soputan on 2-3 July, 9 July, and 14-15 August 2011, all on the volcano's W flank. These were the first such measurements since the volcano's last eruption, during late October to early November 2008 (BGVN 33:09). Since 8 August 2011 to early March 2012, no alerts have been measured.

Geological Summary. The Soputan stratovolcano on the southern rim of the Quaternary Tondano caldera on the northern arm of Sulawesi Island is one of Sulawesi's most active volcanoes. The youthful, largely unvegetated volcano is the only active cone in the Sempu-Soputan volcanic complex, which includes the Soputan caldera, Rindengan, and Manimporok (3.5 km ESE). Kawah Masem maar was formed in the W part of the caldera and contains a crater lake; sulfur has been extracted from fumarolic areas in the maar since 1938. Recent eruptions have originated at both the summit crater and Aeseput, a prominent NE-flank vent that formed in 1906 and was the source of intermittent major lava flows until 1924.

Information Contacts: Center of Volcanology and Geological Hazard Mitigation (CVGHM), Volcanological Survey of Indonesia (VSI), Jalan Diponegoro 57 Bandung, Jawa Barat 40122, Indonesia (URL: http://vsi.esdm.go.id/); Darwin Volcanic Ash Advisory Centre (VAAC), Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, Northern Territory 0811, Australia (URL: http://www.bom.gov.au/info/vaac); MODVOLC, 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/); Jakarta Post (URL: http://www.thejakartapost.com).