PVMBG reported that an eruption at Sinabung was recorded at 2039 on 11 May. An ash plume was not visible due to weather conditions, although crater incandescence was noted. An eruption at 1233 on 12 May was recorded by the seismic network; foggy weather prevented visual confirmation. The Alert Level remained at 4 (on a scale of 1-4), with a general exclusion zone of 3 km and extensions to 7 km on the SSE sector, 6 km in the ESE sector, and 4 km in the NNE 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)