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Report on Merapi (Indonesia) — 26 July-1 August 2006

Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 26 July-1 August 2006
Managing Editor: Sally Kuhn Sennert

Please cite this report as:

Global Volcanism Program, 2006. Report on Merapi (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 26 July-1 August 2006. Smithsonian Institution and US Geological Survey.

Volcano Profile |  Weekly Report (26 July-1 August 2006)


Merapi

Indonesia

7.54°S, 110.446°E; summit elev. 2910 m

All times are local (unless otherwise noted)


Incandescent rock avalanches from Merapi were observed almost daily during 26 July-1 August, advancing at a maximum distance of 2 km SE toward the Gendol River. On 29 July, gas plumes reached maximum heights of 430 m above the summit (11,000 ft a.s.l.). Pyroclastic flows were not observed during the reporting period. The Alert Level remained at 3 (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.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)