Report on Sinabung (Indonesia) — 29 June-5 July 2016
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 29 June-5 July 2016
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2016. Report on Sinabung (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 29 June-5 July 2016. Smithsonian Institution and US Geological Survey.
3.17°N, 98.392°E; summit elev. 2460 m
All times are local (unless otherwise noted)
Based on PVMBG ground-based observations, satellite images, and webcam views, the Darwin VAAC reported that during 29 June-5 July ash plumes from Sinabung rose to altitudes of 3.4-5.5 km (11,000-18,000 ft) a.s.l. and drifted in multiple directions. On 3 July BNPB reported that the eruption at Sinabung continued at a very high level. Lava was incandescent as far as 1 km down the SE and E flanks, and multiple avalanches were detected. An explosion at 1829 generated an ash plume that rose 1.5 km and drifted E and SE, causing ashfall in Medan (55 km NE). The Alert Level remained at 4 (on a scale of 1-4), with an exclusion zone of 7 km from the volcano on the SSE sector, and 6 km in the ESE sector, and 4 km in the NNE sector. There were 2,592 families (9,319 people) displaced to nine shelters, and an additional 1,683 families in temporary shelters waiting for relocation.
Geologic Background. 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.