PVMBG reported that white-and-gray plumes rose 200 m above Sinabung’s summit and drifted E and SE on 12 August. A series of seven eruptions late on 13 August generated ash plumes that rose as high as 2 km and drifted E, SE, and S. The first event, at 0607, lasted for 12 minutes and produced an ash plume that rose 2 km according to BNPB. Seismicity was dominated by continuous tremor during the series. Eruptive events at 1030, 1425, and 1455 on 14 August produced ash plumes that rose as high as 2.1 km and drifted SSE and ESE. An ash plume from an event at 1656 rose 4.2 km and drifted E. At 1724 on 17 August an ash plume rose 1.5 km and drifted SE. Ash plumes rose as high as 2 km on 18 August. The Alert Level remained at 3 (on a scale of 1-4), with a general exclusion zone of 3 km and extensions to 5 km on the SE sector and 4 km in the NE sector.

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), Badan Nacional Penanggulangan Bencana (BNPB)