PVMBG reported that the lava dome in Sinabung’s crater that had been growing since April was destroyed during the 2-3 August events. The dome had grown to an estimated volume of 2.3 million cubic meters. Measurements on 6 August indicated that a new dome had a volume of 23,700 cubic meters.

Based on PVMBG ground observations, the Darwin VAAC reported that on 16 August an ash plume from Sinabung rose to 2.7 km (9,000 ft) a.s.l. and drifted ESE.

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: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM), Darwin Volcanic Ash Advisory Centre (VAAC)