Report on Merapi (Indonesia) — 15 March-21 March 2006
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 15 March-21 March 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, 15 March-21 March 2006. Smithsonian Institution and US Geological Survey.
7.54°S, 110.446°E; summit elev. 2910 m
All times are local (unless otherwise noted)
Increased seismicity at Merapi led CVGHM to raise the Alert Level from 1 to 2 (on a scale of 1-4) around 20 March. According to a news articles, small earthquakes were recorded at the volcano on 19 March and more than 200 were recorded during the week. Around 10,000 residents near the volcano were warned to prepare for possible evacuations if activity escalates.
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.