Report on Soputan (Indonesia) — May 1989
Scientific Event Alert Network Bulletin, vol. 14, no. 5 (May 1989)
Managing Editor: Lindsay McClelland.
Soputan (Indonesia) Tephra eruption follows months of tremor
Please cite this report as:
Global Volcanism Program, 1989. Report on Soputan (Indonesia) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 14:5. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198905-266030
1.112°N, 124.737°E; summit elev. 1785 m
All times are local (unless otherwise noted)
The 22 April eruption . . . was preceded by a significant increase in volcanic tremor, recorded since January. After the eruption's onset at 1027, tephra ejection continued for 45 minutes, followed by additional explosive episodes at 1535 and 1752. The eruption column rose 1-1.5 km, depositing 0.5-3 mm of lapilli and ash on the area 10-32 km E and N of Soputan. No casualties were reported, although ~50 houses and two schools were damaged. By 24 April, both eruptive activity and volcanic tremor had stopped. Volcanic tremor resumed on 6 June at 0745, but as of 9 June, surface activity was limited to weak emission of thin white fume to ~100 m above the crater.
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: VSI.