Report on Tengger Caldera (Indonesia) — 13 July-19 July 2016
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 13 July-19 July 2016
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2016. Report on Tengger Caldera (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 13 July-19 July 2016. Smithsonian Institution and US Geological Survey.
7.942°S, 112.95°E; summit elev. 2329 m
All times are local (unless otherwise noted)
Based on satellite images, wind data, and information from PVMBG, the Darwin VAAC reported that during 13-16 and 19 July ash plumes from Tengger Caldera's Bromo cone rose to altitudes of 2.1-3.3 km (7,000-11,000 ft) a.s.l. and drifted over 45 km NW, SW, and SE. BNPB reported that the Abdul Rachman Saleh Airport in Malang (26 km W) closed again due to ash, from 2307 on 15 July to 0900 on 16 July; six flights were diverted and two were cancelled. Minor amounts of ash fell in the communities of Probolinggo (35 km NE) and Lumajang (36 km SW). The Alert Level remained at 2 (on a scale of 1-4); residents and visitors were reminded not to approach the crater within a radius of 1 km.
Geologic Background. The 16-km-wide Tengger caldera is located at the northern end of a volcanic massif extending from Semeru volcano. The massive volcanic complex dates back to about 820,000 years ago and consists of five overlapping stratovolcanoes, each truncated by a caldera. Lava domes, pyroclastic cones, and a maar occupy the flanks of the massif. The Ngadisari caldera at the NE end of the complex formed about 150,000 years ago and is now drained through the Sapikerep valley. The most recent of the calderas is the 9 x 10 km wide Sandsea caldera at the SW end of the complex, which formed incrementally during the late Pleistocene and early Holocene. An overlapping cluster of post-caldera cones was constructed on the floor of the Sandsea caldera within the past several thousand years. The youngest of these is Bromo, one of Java's most active and most frequently visited volcanoes.