Report on Sinabung (Indonesia) — 26 August-1 September 2020
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 26 August-1 September 2020
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2020. Report on Sinabung (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 26 August-1 September 2020. Smithsonian Institution and US Geological Survey.
3.17°N, 98.392°E; summit elev. 2460 m
All times are local (unless otherwise noted)
PVMBG reported that white-and-gray plumes rose as high as 2 km above Sinabung’s summit and drifted in multiple directions during 18-20, 23-25, and 31 August. An eruptive event was recorded at 0517, though weather conditions prevented visual confirmation. White plumes were seen rising 100-400 m during 22 and 26-30 August. Notably, at 1823 on 19 August an ash plume rose 4 km above the crater rim and drifted ESE. At 0741 on 23 August a gray ash plume rose 1.5 km and drifted E; pyroclastic flows traveled about 1 km down the E and SE flanks. The Alert Level remained at 3 (on a scale of 1-4), with a general exclusion zone of 3 km and extensions to 5 km on the SE sector and 4 km in the NE sector.
Geologic Background. Gunung Sinabung is a Pleistocene-to-Holocene stratovolcano with many lava flows on its flanks. The migration of summit vents along a N-S line gives the summit crater complex an elongated form. The youngest crater of this conical andesitic-to-dacitic edifice is at the southern end of the four overlapping summit craters. The youngest deposit is a SE-flank pyroclastic flow 14C dated by Hendrasto et al. (2012) at 740-880 CE. An unconfirmed eruption was noted in 1881, and solfataric activity was seen at the summit and upper flanks in 1912. No confirmed historical eruptions were recorded prior to explosive eruptions during August-September 2010 that produced ash plumes to 5 km above the summit.