Report on Merapi (Indonesia) — 24 August-30 August 2022
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
24 August-30 August 2022
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2022. Report on Merapi (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 24 August-30 August 2022. Smithsonian Institution and US Geological Survey.
7.54°S, 110.446°E; summit elev. 2910 m
All times are local (unless otherwise noted)
BPPTKG reported that the eruption at Merapi continued during 19-25 August. Seismicity intensified compared to the previous week; in particular the number of deep volcanic earthquakes increased and indicated magmatic activity at depths less than 1.5 km. As many as 19 lava avalanches traveled down the Bebeng drainage on the SW flank, reaching a maximum distance of 1.8 km. Photo analyses showed no height changes at the SW and central lava domes, though some changes at the SW dome were observed due to avalanche activity. The Alert Level remained at 3 (on a scale of 1-4), and the public was warned to stay 3-7 km away from the summit based on location.
Geological Summary. 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 2,000 years ago, leaving a large arcuate scarp cutting the eroded older Batulawang volcano. Subsequent growth of the steep-sided Young Merapi edifice, its upper part unvegetated due to frequent 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.