Based on satellite images, webcam views, weather models, and information from PVMBG, the Darwin VAAC reported that on 23 July an explosion at Sinabung generated an ash plume that rose to an altitude of 7 km (23,000 ft) a.s.l. and drifted 25-55 km W. An explosion on 26 July generated an ash plume that rose to an altitude of 3.7 km (12,000 ft) a.s.l. and drifted E.

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: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)