PVMBG reported that the eruption at Sinabung continued during 12-18 May. Weather conditions often prevented visual observations of the volcano; white fumarolic plumes were visible on 11, 13, and 15 May rising as high as 700 m above the summit and drifting in multiple directions. On 11 May an eruptive event produced a gray ash plume that rose up to 1 km. Avalanches of material traveled 1 km down the E and SE flanks on 12 May. On 13 May gray ash plumes rose 700-1,000 m above the summit, pyroclastic flows traveled 2.5 km down the E and SE flanks, and avalanches moved down the E and SE flanks as far as 1 km. On 14 May pyroclastic flows traveled as far as 4 km SE. 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 in 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.

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