Based on webcam data, wind data, satellite image analysis, and PVMBG, the Darwin VAAC reported that on 4 December an ash plume from Sinabung rose to an altitude of 8.2 km (27,000 ft) a.s.l. and drifted N. Later that day and during 5-6 December ash plumes rose to altitudes of 3-3.7 km (7,000-12,000 ft) a.s.l. and drifted NW. On 10 December an ash plume rose to an altitude of 5.5 km (18,000 ft) a.s.l. and drifted 75 km NW. A few hours later an ash plume rose to an altitude of 11.6 km (38,000 ft) a.s.l. and drifted over 90 km NW.

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.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)