According to the Darwin VAAC, the webcam recording activity at Sinabung showed on 18 September that ash had dissipated. The VAAC also noted that PVMBG confirmed Sinabung was degassing and not emitting any ash. According to a news article, about 6,000 people that had evacuated after the 15 September eruption started to return home on 22 September. The article noted that the volcano was continuing to emit ash.

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), The Jakarta Post