Report on Merapi (Indonesia) — 5 July-11 July 2006
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 5 July-11 July 2006
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2006. Report on Merapi (Indonesia) (Sennert, S, ed.). Weekly Volcanic Activity Report, 5 July-11 July 2006. Smithsonian Institution and US Geological Survey.
7.54°S, 110.446°E; summit elev. 2910 m
All times are local (unless otherwise noted)
Gas plumes were observed during 5-11 July at Merapi and reached a maximum height of 1.2 km above the summit (3,600 ft a.s.l.) on 6 July. Due to a decrease in activity, on 10 July the Alert Level was lowered one level to 3 (on a scale of 1-4) in all areas except the S slope.
Geological Summary. Merapi, one of Indonesia's most active volcanoes, lies in one of the world's most densely populated areas and dominates the landscape immediately north of the major city of Yogyakarta. It is the youngest and southernmost of a volcanic chain extending NNW to Ungaran volcano. Growth of Old Merapi during the Pleistocene ended with major edifice collapse perhaps about 2,000 years ago, leaving a large arcuate scarp cutting the eroded older Batulawang volcano. Subsequent growth of the steep-sided Young Merapi edifice, its upper part unvegetated due to frequent activity, began SW of the earlier collapse scarp. Pyroclastic flows and lahars accompanying growth and collapse of the steep-sided active summit lava dome have devastated cultivated lands on the western-to-southern flanks and caused many fatalities.