Report on Soputan (Indonesia) — 20 April-26 April 2005
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
20 April-26 April 2005
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2005. Report on Soputan (Indonesia). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 20 April-26 April 2005. Smithsonian Institution and US Geological Survey.
1.112°N, 124.737°E; summit elev. 1785 m
All times are local (unless otherwise noted)
Soputan began to erupt on 20 April at 0630, with a plume reaching ~1 km above the volcano's summit (~9,100 ft a.s.l.) and drifting SE. In addition, lava fountains rose ~200 m above the volcano (~6,500 ft a.s.l.). During 20 April at 1720 to 21 April at 0900, lava fountains rose 75-100 m above the volcano (6,100-6,200 ft a.s.l.). Rapid dome growth occurred and by 21 April the lava dome had spread about 250 m E and 200 m SW. On 22 April a "white ash plume" rose ~100 m above the volcano (~6,200 ft. a.s.l.) and on 23 April a "dark gray ash" plume rose to ~150 m (~6,300 ft a.s.l.) and drifted NE. Ash eruptions continued through 24 April, producing plumes to ~300 m above the volcano (~6,800 ft a.s.l.). Soputan was at Alert Level 2 (on a scale of 1-4).
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.