Report on Marapi (Indonesia) — 4 August-10 August 2004
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 4 August-10 August 2004
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2004. Report on Marapi (Indonesia). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 4 August-10 August 2004. Smithsonian Institution and US Geological Survey.
0.381°S, 100.473°E; summit elev. 2891 m
All times are local (unless otherwise noted)
Increased volcanic activity at Marapi during early August led DVGHM to raise the Alert Level to 2 from 1 (on a scale of 1-4) on 5 August. Ash explosions rose 500-1,000 m above the summit and no seismic data were available. Visitors and villagers in the Tanah Datar and Padang Panjang districts were advised not to climb the volcano.
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.