Report on Merapi (Indonesia) — 26 March-1 April 2014
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
26 March-1 April 2014
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2014. Report on Merapi (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 26 March-1 April 2014. 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 explosions from Merapi on 9 March. An explosion detected at 0654 was followed by a plume observed on CCTV from Pasarbubar that drifted W. Two Explosions were also recorded at 0655. At 0708 a volcanic earthquake occurred and CCTV in Market Bubar recorded brown plumes that rose 1.5 km above the crater. At 0730 ash fell in the villages of Umbulharjo (30 km S), Kepuharjo, Sidorejo (27 km NNE), and Balerante (6 km SSE). During 14-20 March dense gas plumes rose 600 m. Seismicity was at normal levels. The Alert Level remained at 1 (on a scale of 1-4).
Based on analysis of satellite images, the Darwin VAAC reported that on 27 March an ash plume rose to an altitude of 9.8 km (32,000 ft) a.s.l. and drifted SE. The VAAC noted that an eruption occurred around 0630, confirmed by a news article. Ash had dissipated the next day. Another news article noted that the increased activity lasted only four minutes, from 0112 to 0116, and that ashfall occurred on the S and SE flanks.
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.