CVGHM reported a white plume that was occasionally brown and blue reaching 100-2,000 m above Sinabung’s crater during 8-14 July. Pyroclastic flows were observed on 10 and 12 July from the W side of the crater. On 10 July, the hot flows reached a maximum of 3 km S while the flows on 12 July extended 3-4 km S. A spokesman from the national disaster management agency noted that hot ashfall occurred in several places around the Karo district, but did not merit further evacuations. CVGHM reported that SO2 emissions were measured once during 8-14 July and yielded 1,252 tonnes/day; during the elevated activity of 11-18 January 2014 values were as high as 3,796 tonnes/day. The Alert Level remained at 3 (on a scale of 1-4).

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), GlobalPost.com