Report on Merapi (Indonesia) — 18 July-24 July 2001
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 18 July-24 July 2001
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2001. Report on Merapi (Indonesia). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 18 July-24 July 2001. Smithsonian Institution and US Geological Survey.
7.54°S, 110.446°E; summit elev. 2910 m
All times are local (unless otherwise noted)
During 9-15 July volcanic activity at Merapi was similar to the previous week. A total of 52 lava avalanches traveled SW to a maximum distance of 2.5 km down the Sat, Senowo, and Lamat rivers. Emissions from low-pressure fumaroles rose to 755 m above the summit. The volcano remained at Alert Level 2 (on a scale of 1-4).
Geologic Background. 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 2000 years ago, leaving a large arcuate scarp cutting the eroded older Batulawang volcano. Subsequently growth of the steep-sided Young Merapi edifice, its upper part unvegetated due to frequent eruptive 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 during historical time.