Report on Dieng Volcanic Complex (Indonesia) — 8 May-14 May 2013
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 8 May-14 May 2013
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2013. Report on Dieng Volcanic Complex (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 8 May-14 May 2013. Smithsonian Institution and US Geological Survey.
Dieng Volcanic Complex
7.2°S, 109.879°E; summit elev. 2565 m
All times are local (unless otherwise noted)
CVGHM reported that on 28 March gas emissions continued to be elevated at Timbang, a cone that is part of the Dieng Volcanic Complex. Plumes containing carbon dioxide drifted 2 km towards the S valley of Kali Sat, prompting a road closure until the early evening when the gas concentration decreased. On 30 March carbon dioxide gas emissions were not detected; however, "smoke" rose at most 100 m above the crater. Hydrogen sulfide odors were very potent in areas 1 km W and weak in areas 1.5 km S. On 19 April sulfur dioxide odors were reported.
On 24 March Sileri Crater lake water changed from dark gray to brown. On 7 April white plumes rose 50 m and the water color returned to normal. Diffuse white plumes rose 15 m on 20 April. Other craters had not exhibited any changes by 28 April.
Based on gas concentrations, seismicity, and visual observations, CVGHM raised the Alert Level to 3 (on a scale of 1-4) on 8 May and warned the public not to approach Timbang Crater within a 500-m radius.
Geologic Background. The Dieng plateau in the highlands of central Java is renowned both for the variety of its volcanic scenery and as a sacred area housing Java's oldest Hindu temples, dating back to the 9th century CE. The Dieng volcanic complex consists of two or more stratovolcanoes and more than 20 small craters and cones of Pleistocene-to-Holocene age over a 6 x 14 km area. Prahu stratovolcano was truncated by a large Pleistocene caldera, which was subsequently filled by a series of dissected to youthful cones, lava domes, and craters, many containing lakes. Lava flows cover much of the plateau, but have not occurred in historical time, when activity has been restricted to minor phreatic eruptions. Toxic gas emissions are a hazard at several craters and have caused fatalities. The abundant thermal features and high heat flow make Dieng a major geothermal prospect.