Report on Chaiten (Chile) — 2 September-8 September 2009
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 2 September-8 September 2009
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2009. Report on Chaiten (Chile) (Sennert, S, ed.). Weekly Volcanic Activity Report, 2 September-8 September 2009. Smithsonian Institution and US Geological Survey.
42.8349°S, 72.6514°W; summit elev. 1122 m
All times are local (unless otherwise noted)
SERNAGEOMIN reported that during 20-31 August Chaitén's Domo Nuevo 1 and Domo Nuevo 2 lava-dome complex continued to grow, particularly in the W area of the complex. Collapses originating from unstable slopes generated block-and-ash flows, and gas-and-ash plumes occasionally rose 1.5 km above the lava domes. The Alert Level remained at Red. Based on web camera views and analyses of satellite imagery, the Buenos Aires VAAC reported that on 6 September an ash plume rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted E. The next day, a plume rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted NE.
Geological Summary. Chaitén is a small caldera (~3 km in diameter) located 10 km NE of the town of Chaitén on the Gulf of Corcovado. Multiple explosive eruptions throughout the Holocene have been identified. 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 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 recorded eruption, beginning in 2008, produced major rhyolitic explosive activity and building a new dome and tephra cone on the older rhyolite dome.