Report on Chaiten (Chile) — 10 November-16 November 2010
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 10 November-16 November 2010
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2010. Report on Chaiten (Chile). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 10 November-16 November 2010. Smithsonian Institution and US Geological Survey.
42.833°S, 72.646°W; summit elev. 1122 m
All times are local (unless otherwise noted)
On 11 November, SERNAGEOMIN reported that, although seismic events at Chaitén's lava-dome complex continued to increase in the previous weeks, the magnitudes of the earthquakes remained relatively low. Gas-and-steam plumes rose 300-400 m above the caldera rim. Based on analyses of satellite imagery and web camera footage, the Buenos Aires VAAC reported that on 13 November a gas-and-ash plume rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted 40 km SE. On 15 November ash plumes observed through the web camera rose to altitudes of 1.8-2.1 km (6,000-7,000 ft) a.s.l. and drifted E. The Alert Level remained Yellow Level 3 on a three-color scale.
Geologic Background. 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.