Report on Sinabung (Indonesia) — 14 February-20 February 2018
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 14 February-20 February 2018
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2018. Report on Sinabung (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 14 February-20 February 2018. 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 at 0853 on 19 February a large explosive event at Sinabung generated a dark gray plume with a high volume of ash that rose at least to 16.8 km (55,000 ft) a.s.l. According to the Darwin VAAC, ash plumes that were identified in satellite images, recorded by webcams, and reported by PVMBG continued to rise throughout the day to 13.7 km (45,000 ft) a.s.l. and drift 320 km NNW. Parts of the ash plumes drifted in multiple directions at lower altitudes. As many as 10 pyroclastic flows were observed, traveling as far as 4.9 km SSE and 3.5 km E. Ash and tephra as large as pebbles fell in areas downwind including Simpang Empat (7 km SE), the Namanteran district, Pqyung (5 km SSW), Tiganderket (7 km W), Munthe, Kutambaru (20 km NW), Perbaji (4 km SW), and Kutarayat. Conditions in five districts were so dark that visibility was only about 5 m. Some residents outside of the evacuation zone self-evacuated. The event was possibly the largest since the beginning of the current eruption, which began in September 2013. The Alert Level remained at 4 (on a scale of 1-4), with a general exclusion zone of 3 km and extensions of 7 km on the SSE sector, 6 km in the ESE sector, and 4 km in the NNE 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.