Report on Marapi (Indonesia) — 5 October-11 October 2011
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 5 October-11 October 2011
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2011. Report on Marapi (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 5 October-11 October 2011. Smithsonian Institution and US Geological Survey.
0.381°S, 100.473°E; summit elev. 2891 m
All times are local (unless otherwise noted)
Based on a pilot report, the Darwin VAAC reported that on 11 October an ash plume from Marapi rose to an altitude of 3.7 km (12,000 ft) a.s.l. Ash was not identified in satellite imagery.
Geologic Background. Gunung Marapi, not to be confused with the better-known Merapi volcano on Java, is Sumatra's most active volcano. This massive complex stratovolcano rises 2000 m above the Bukittinggi plain in the Padang Highlands. A broad summit contains multiple partially overlapping summit craters constructed within the small 1.4-km-wide Bancah caldera. The summit craters are located along an ENE-WSW line, with volcanism migrating to the west. More than 50 eruptions, typically consisting of small-to-moderate explosive activity, have been recorded since the end of the 18th century; no lava flows outside the summit craters have been reported in historical time.