Report on Raung (Indonesia) — 15 April-21 April 2015
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 15 April-21 April 2015
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2015. Report on Raung (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 15 April-21 April 2015. Smithsonian Institution and US Geological Survey.
8.119°S, 114.056°E; summit elev. 3260 m
All times are local (unless otherwise noted)
PVMBG reported that, during infrequent times of clear weather in December 2014 and January 2015, white plumes were observed rising as high as 500 m above Raung's crater rim. In February and during 1-14 March plumes were gray-white and rose to a maximum height of 200 m. Crater incandescence and rumbling was reported. During 15 March-7 April emissions were gray-brown and rose as high as 200 m; rumbling continued to be heard. During 8-15 April gray-brown plumes rose as high as 300 m. Rumbling was heard on 8 April and crater incandescence was observed on 12 April. Continuous tremor was recorded during December 2014-12 January 2015; tremor was not continuous starting on 13 January, and RSAM values declined. The Alert Level remained at 2 (on a scale of 1-4).
Geologic Background. Raung, one of Java's most active volcanoes, is a massive stratovolcano in easternmost Java that was constructed SW of the rim of Ijen caldera. The unvegetated summit is truncated by a dramatic steep-walled, 2-km-wide caldera that has been the site of frequent historical eruptions. A prehistoric collapse of Gunung Gadung on the W flank produced a large debris avalanche that traveled 79 km, reaching nearly to the Indian Ocean. Raung contains several centers constructed along a NE-SW line, with Gunung Suket and Gunung Gadung stratovolcanoes being located to the NE and W, respectively.