On 19 February BNPB reported that villagers outside of the 5-km evacuation zone around Sinabung continued to return to their homes. Based on wind data and satellite images, the Darwin VAAC reported that during 19 and 21-22 February ash plumes rose to an altitude of 4.6 km (15,000 ft) a.s.l. and drifted 25-35 km NE and SW. Ash plumes were visible in webcam images during 23-25 February; ash plumes rose to altitudes of 3.7-4.6 km (12,000-15,000 ft) a.s.l. on 25 February and drifted 45 km E. On 24 February BNPB noted that 16,361 people remained in 34 evacuation shelters. Dense white plumes rose 100-300 m above the dome and incandescent material as far as 2 km SE from the dome was observed.

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