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Report on Sorikmarapi (Indonesia) — August 1987


Scientific Event Alert Network Bulletin, vol. 12, no. 8 (August 1987)
Managing Editor: Lindsay McClelland.

Sorikmarapi (Indonesia) Seismicity and fumarole temperatures increase

Please cite this report as:

Global Volcanism Program, 1987. Report on Sorikmarapi (Indonesia) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 12:8. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198708-261120



0.686°N, 99.539°E; summit elev. 2145 m

All times are local (unless otherwise noted)

Temperatures increased at two fumaroles during August: from 104 to 197°C at the N crater, and from 95 to 108°C at Sibangor Julu. White fume was almost continuously present, rising to ~100 m above the crater. In late August, seismic activity began to increase. By early September, near-surface earthquakes averaged ~7/day and deeper, tectonic earthquakes averaged ~40/day.

Geological Summary. Sorikmarapi is a forested stratovolcano with a 600-m-wide summit crater containing a lake and substantial sulfur deposits. A smaller upper SE flank crater (Danau Merah) also contains a crater lake; these two craters and a series of smaller explosion pits occur along a NW-SE line. Several solfatara fields are located on the E flank. Phreatic eruptions have occurred from summit and flank vents during the 19th and 20th centuries.

Information Contacts: VSI.