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Report on Soputan (Indonesia) — June 1991


Bulletin of the Global Volcanism Network, vol. 16, no. 6 (June 1991)
Managing Editor: Lindsay McClelland.

Soputan (Indonesia) Ash and vapor ejected but glow ends in late May; 50 m of new lava on crater floor

Please cite this report as:

Global Volcanism Program, 1991. Report on Soputan (Indonesia) (McClelland, L., ed.). Bulletin of the Global Volcanism Network, 16:6. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199106-266030



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

All times are local (unless otherwise noted)

Emissions of moderate to weak white-gray ash and vapor rose 100-300 m in June, but the weak red glow visible over the crater since 22 May, vanished on 29 May. During fieldwork on 18 June, the crater floor (50 m in diameter) was covered by ~50 m of lava (approximate volume 2.4 x 106 m3). Seismographs recorded 101 tectonic and 97 explosion earthquakes weekly, but no volcanic earthquakes were detected. An M 5.6 earthquake occurred on 20 June at 1319 in the Sulawesi Sea ~200 km NW of the volcano at 1.15°N, 122°E. The shock was felt (MM III) near Soputan.

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: W. Modjo, VSI.