Based on satellite images and weather models, the Darwin VAAC reported that on 15 January an ash plume from Sinabung rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted over 45 km NW. On 18 January BNPB reported that activity at Sinabung remained high; low-frequency earthquakes and constant tremor were detected. A pyroclastic flow traveled 2 km S and ash plumes rose 700 m. The number of people that remained displaced was 2,443 (795 families). The Alert Level was at 3 (on a scale of 1-4).

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.

Sources: Darwin Volcanic Ash Advisory Centre (VAAC), Badan Nacional Penanggulangan Bencana (BNPB)