Report on Galunggung (Indonesia) — 23 May-29 May 2012

Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 23 May-29 May 2012
Managing Editor: Sally Kuhn Sennert

Please cite this report as:

Global Volcanism Program, 2012. Report on Galunggung (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 23 May-29 May 2012. Smithsonian Institution and US Geological Survey.

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Galunggung

Indonesia

7.25°S, 108.058°E; summit elev. 2168 m

All times are local (unless otherwise noted)


CVGHM reported that, since the Alert Level was raised on 12 February, seismic activity at Galunggung had drastically decreased through 27 May. During 27 April-27 May plants around the crater area looked green and lush, small fish were swimming in the water, and insects around the crater were active. Based on seismic data, crater lake water temperature and pH data, and visual observations, CVGHM lowered the Alert Level from 2 to 1 (on a scale of 1-4) on 28 May.

Geologic Background. The forested slopes Galunggung in western Java are cut by a large horseshoe-shaped caldera breached to the SE that has served to channel the products of recent eruptions in that direction. The "Ten Thousand Hills of Tasikmalaya" dotting the plain below the volcano are debris-avalanche hummocks from the collapse that formed the breached caldera about 4200 years ago. Although historical eruptions, restricted to the central vent near the caldera headwall, have been infrequent, they have caused much devastation. The first historical eruption in 1822 produced pyroclastic flows and lahars that killed over 4000 people. More recently, a strong explosive eruption during 1982-1983 caused severe economic disruption to populated areas near the volcano.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)