Report on Dempo (Indonesia) — 9 September-15 September 2015
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 9 September-15 September 2015
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2015. Report on Dempo (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 9 September-15 September 2015. Smithsonian Institution and US Geological Survey.
4.016°S, 103.121°E; summit elev. 3142 m
All times are local (unless otherwise noted)
Observers at the PVMBG Dempo observation post reported that during 1 June-9 September no plumes rose from Dempo's crater and seismicity was low. On 10 September the Alert Level was lowered to 1 (on a scale from 1-4). Visitors and residents were advised not to approach the craters.
Geologic Background. Dempo is a prominent stratovolcano that rises above the Pasumah Plain of SE Sumatra. The andesitic volcanic complex has two main peaks, Gunung Dempo and Gunung Marapi, constructed near the SE rim of a 3 x 5 km caldera breached to the north. The Dempo peak is slightly lower, and lies at the SE end of the summit complex. The taller Marapi cone was constructed within a crater cutting the older Gunung Dempo edifice. Remnants of seven craters are found at or near the summit, with volcanism migrating WNW over time. The large, 800 x 1100 m wide historically active crater cuts the NW side of the Marapi cone and contains a 400-m-wide lake located at the far NW end of the crater complex. Historical eruptions have been restricted to small-to-moderate explosive activity that produced ashfall near the volcano.