Report on Sinabung (Indonesia) — 21 April-27 April 2021
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
21 April-27 April 2021
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2021. Report on Sinabung (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 21 April-27 April 2021. 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 the eruption at Sinabung continued during 21-27 April. Weather conditions sometimes prevented visual observations of the volcano, though white fumarolic plumes were visible almost daily rising as high as 700 m above the summit and drifted E and SE. Pyroclastic flows traveled 2 km on 21 April. Avalanches of material traveled 1 km E and SE during 23-24 April. Ash plumes rose 2 km above the summit on 24 April and to 1 km on 25 April, drifting ESE both days. 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 in the SE sector and 4 km in the NE sector.
Geological Summary. 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.