Report on Soputan (Indonesia) — 12 December-18 December 2018
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
12 December-18 December 2018
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2018. Report on Soputan (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 12 December-18 December 2018. Smithsonian Institution and US Geological Survey.
1.112°N, 124.737°E; summit elev. 1785 m
All times are local (unless otherwise noted)
PVMBG reported that seismic activity at Soputan rapidly and significantly increased at 1700 on 15 December. An eruption began at 0102 on 16 December though dark and foggy conditions prevented views of emissions. The event lasted for almost 10 minutes, and thunderous sounds were heard at the Soputan Volcano Observation Post located in Silian Raya (about 10 km SW). The conditions improved about two hours later, and a dense ash plume was visible rising 3 km above the summit and drifting SE. Incandescence from the summit was also visible. An event that began at 0540 produced dense gray-to-black ash plumes that rose as high as 7 km above the summit and drifted SE. The event lasted for 6 minutes and 10 seconds based on the seismic network. Ash plumes from events at 0743 and 0857 rose as high as 7.5 km and drifted SW. The Alert Level remained at 3 (on a scale of 1-4). Residents and tourists were advised not to approach the craters within a radius of 4 km, or 6.5 km on the WSW flank.
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.