Report on Sinabung (Indonesia) — 1 January-7 January 1920
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 1 January-7 January 1920
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 1920. Report on Sinabung (Indonesia). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 1 January-7 January 1920. Smithsonian Institution and US Geological Survey.
3.17°N, 98.392°E; summit elev. 2460 m
All times are local (unless otherwise noted)
The initial phreatic eruption on 27 August heralding the first historic eruption. By 30 August there had been 20,000-30,000 residents evacuated. The next months were characterized by fluctuating but overall increasing levels of activity, and cycles of residents being evacuated and returning to their homes. On 25 November BNPB reported that 17,713 people, out of the 20,270 residents living within 5 km, had been evacuated to 31 shelters. At 1030 on 1 February a large dome collapse generated pyroclastic flows that traveled 4.5 km S, killing 17 people that had entered the 5-km exclusion zone without permission. BNPB lists the victims’ names and their ages; I was saddened to see so many young people among the deceased. On 4 February the number of displaced people reached 31,739 (9,915 families) in 42 evacuation centers, many from outside of the exclusion zone. Activity continued through mid-2018. An eruption period was recorded in mid-2019, and activity again returned in 2020.
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.