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Report on Chaiten (Chile) — 16 December-22 December 2009


Chaiten

Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 16 December-22 December 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, 16 December-22 December 2009. Smithsonian Institution and US Geological Survey.

Weekly Report (16 December-22 December 2009)

Chaiten

Chile

42.8349°S, 72.6514°W; summit elev. 1122 m

All times are local (unless otherwise noted)


SERNAGEOMIN reported that during 1-15 December Chaitén's lava-dome complex produced steam, gas, and ash plumes that rose 2 km above the lava domes. On 7 December emissions originated from the N and S areas of the complex. Block-and-ash flows were noted the next day. The Alert Level remained at Red. Based on web camera views and SIGMET notices, the Buenos Aires VAAC reported that on 18 December an ash plume drifted SSE at altitudes of 1.8-2.4 km (6,000-8,000 ft) a.s.l.

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.

Sources: Servicio Nacional de Geología y Minería (SERNAGEOMIN), Buenos Aires Volcanic Ash Advisory Center (VAAC)