Report on Merapi (Indonesia) — 9 October-15 October 2019
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 9 October-15 October 2019
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2019. Report on Merapi (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 9 October-15 October 2019. Smithsonian Institution and US Geological Survey.
7.54°S, 110.446°E; summit elev. 2910 m
All times are local (unless otherwise noted)
PVMBG reported that the lava dome at Merapi slowly grew during 3-10 October and was an estimated 468,000 cubic meters, based on 19 September drone photos. At 1631 on 14 October an eruptive event was recorded by the seismic network for four minutes and 30 seconds. A plume rose 3 km above the summit and drifted SW, causing ashfall 30 minutes after the eruption until 1900 in areas as far as 25 km W. A pyroclastic flow traveled down the SW flank. The Alert Level remained at 2 (on a scale of 1-4), and residents were warned to stay outside of the 3-km exclusion zone.
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.