Report on Chaiten (Chile) — 24 December-30 December 2008
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 24 December-30 December 2008
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2008. Report on Chaiten (Chile) (Sennert, S, ed.). Weekly Volcanic Activity Report, 24 December-30 December 2008. Smithsonian Institution and US Geological Survey.
42.833°S, 72.646°W; summit elev. 1122 m
All times are local (unless otherwise noted)
SERNAGEOMIN reported that, although inclement weather mostly prevented observations of Chaitén during 24-29 December, a gas-and-steam plume was seen on a web camera rising above Domo Nuevo 2 on 25 and 28 December. The plume was brown mainly at the base and rose to an altitude of about 3.1 km (10,200 ft) a.s.l. The Alert Level remained Red.
Based on analysis of satellite imagery and web camera views, the Buenos Aires VAAC reported that during 25-26 and 29 December ash plumes continuously rose to altitudes 2-2.1 km (6,500-7,000 ft) a.s.l. and drifted NNE.
Geological Summary. Chaitén is a small, glacier-free caldera with a compound Holocene lava dome located 10 km NE of the town of Chaitén on the Gulf of Corcovado. Early work had identified only a single explosive eruption during the early Holocene prior to the major 2008 eruption, but later work has identified multiple explosive eruptions throughout the Holocene. A rhyolitic obsidian lava dome occupies much of the caldera floor. Obsidian cobbles from this dome found in the Blanco River are the source of prehistorical artifacts from archaeological sites along the Pacific coast as far as 400 km from the volcano to the N and S. The caldera is breached on the SW side by a river that drains to the bay of Chaitén. The first historical eruption, beginning in 2008, produced major rhyolitic explosive activity and growth of a lava dome that filled much of the caldera.