Report on Soputan (Indonesia) — 29 June-5 July 2011
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 29 June-5 July 2011
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2011. Report on Soputan (Indonesia) (Sennert, S, ed.). Weekly Volcanic Activity Report, 29 June-5 July 2011. Smithsonian Institution and US Geological Survey.
1.112°N, 124.737°E; summit elev. 1785 m
All times are local (unless otherwise noted)
CVGHM reported that during June diffuse white plumes from Soputan rose 25-150 m. During 21 June-2 July seismicity increased, and on 2 July the Alert Level was raised to 3 (on a scale of 1-4). Visitors and residents were discouraged from going within a 6-km radius of the crater and climbing the volcano was prohibited. According to news articles, a CVGHM volcanologist reported that a Strombolian eruption that began on 3 July produced an ash plume that rose 6 km and drifted W. Ashfall impacted villages, trees, and vegetation downwind. Sam Ratulangi International airport in the capital of Manado was closed for three hours. Articles also stated that the Red Cross distributed about 31,000 masks to area residents.
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.