Report on Tengger Caldera (Indonesia) — 17 November-23 November 2010
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 17 November-23 November 2010
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2010. Report on Tengger Caldera (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 17 November-23 November 2010. Smithsonian Institution and US Geological Survey.
7.942°S, 112.95°E; summit elev. 2329 m
All times are local (unless otherwise noted)
CVGHM reported that during November seismicity from Tengger Caldera increased, and volcanic tremor was first detected on 8 November. The heights of gas-and-steam plumes increased during the month, going from 75 m above the crater during 1-7 November to100-250 m above the crater during 8-23 November. The Alert Level was raised to 3 (on a scale of 1-4) on 23 November. Residents and tourists were not permitted within a 3-km-radius of the active crater. Later that night, seismic activity increased and a white-to-gray plume rose 200-300 m above the crater. The Alert Level was raised to 4. The tourist areas surrounding Tengger Caldera was closed.
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.