Report on Sundoro (Indonesia) — 7 December-13 December 2011
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 7 December-13 December 2011
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2011. Report on Sundoro (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 7 December-13 December 2011. Smithsonian Institution and US Geological Survey.
7.3°S, 109.992°E; summit elev. 3136 m
All times are local (unless otherwise noted)
CVGHM reported increased seismic activity at Sundoro during October -4 December. On 26 November and 2 December smoke was reported from many fumaroles around the summit crater. Based on visual and seismic data, CVGHM raised the Alert Level from 1 to 2 (on a scale of 1-4) on 5 December.
Geologic Background. Gunung Sundoro, one Java's most symmetrical volcanoes, is separated by a 1400-m-high saddle from Sumbing volcano. Parasitic craters and cones, the largest of which is Kembang, occur on the NW-to-southern flanks, and all fed lava flows. A small lava dome occupies the summit crater, and numerous phreatic explosion vents were formed along radial fissure that cut the dome and extend across the crater rim. Lava flows extend in all directions from the summit crater. Deposits of a large prehistoric debris avalanche are located below the NE flank. Pyroclastic-flow deposits dated at 1720 years before present extend as far as 13 km from the summit. Historical eruptions typically have consisted of mild-to-moderate phreatic explosions, mostly from the summit crater. Flank vents were also active in 1882 and 1903.