Report on Chaiten (Chile) — 24 September-30 September 2008
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 24 September-30 September 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 September-30 September 2008. Smithsonian Institution and US Geological Survey.
42.833°S, 72.646°W; summit elev. 1122 m
All times are local (unless otherwise noted)
Based on web camera views and analysis of satellite imagery, the Buenos Aires VAAC reported that during 25-30 September continuous ash plumes rose to altitudes of 2.1-2.7 km (7,000-9,000 ft) a.s.l. and drifted E, ESE, and SE. A thermal anomaly over the lava dome was detected by satellite imagery during 25-27 September. On 26 September, SERNAGEOMIN reported that Chaitén continued to produce two gas-and-ash plumes that rose to altitudes of 2.6-3.1 km (8,500-10,200 ft) a.s.l. and drifted NE.
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.