PVMBG reported that the eruption at Sinabung continued during 28 April-4 May. Weather conditions sometimes prevented visual observations of the volcano, though white fumarolic plumes were visible almost daily rising as high as 500 m above the summit and drifted in multiple directions. At 0728 on 28 April an ash plume rose 1 km and drifted SSW. At 1810 an ash plume rose 1 km and drifted SSE and an incandescent avalanche descended 1.5 km down the SSE flank. At 2346 an ash plume rose 1.5 km and drifted W and SW, and another incandescent rockfall traveled 1.5 km SSE. Eruptive events produced ash plumes that rose 500-1,000 m above the summit during 30 April-1 May. Avalanches of material traveled as far as 1.5 km E and 1 km SE during 1-3 May. 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)