Report on Merapi (Indonesia) — 13 February-19 February 2002
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 13 February-19 February 2002
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2002. Report on Merapi (Indonesia). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 13 February-19 February 2002. Smithsonian Institution and US Geological Survey.
7.54°S, 110.446°E; summit elev. 2910 m
All times are local (unless otherwise noted)
During 11-17 February there were 65 incandescent lava avalanches observed traveling down Merapi's flanks, predominately WSW to the upstream portions of Lamat and Senowo rivers and partly SW toward the Sat and Bebeng rivers. The maximum run-out distance was ~2.5 km. During the report period, six minor pyroclastic flows traveled up to 2.5 km to the upstream portions of the Lamat and Senowo rivers. According to news reports, Volcanology Development and Investigation Agency staff stated that intense rain during the current rainy season could cause landslides around the volcano's crater. Merapi 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.