Report on Puyehue-Cordon Caulle (Chile) — 9 November-15 November 2011
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 9 November-15 November 2011
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2011. Report on Puyehue-Cordon Caulle (Chile). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 9 November-15 November 2011. Smithsonian Institution and US Geological Survey.
40.59°S, 72.117°W; summit elev. 2236 m
All times are local (unless otherwise noted)
Based on seismicity during 9-13 November, OVDAS-SERNAGEOMIN reported that the eruption from the Cordón Caulle rift zone, part of the Puyehue-Cordón Caulle volcanic complex, continued at a low level. During 9-10 November clouds prevented observations with an area web camera, but on 9 November satellite imagery showed an ash plume that drifted and dissipated to the E. During 11-12 November mostly gray plumes observed with the web camera rose 4-7 km above the crater. During the night the crater was incandescent and small explosions were observed. Satellite imagery showed ash plumes drifting 90 km NE on 11 November and 400 km SE on 12 November. Ash fell in areas on the border of Chile and Argentina at Paso Samore on 12 November. Cloud cover prevented web camera views on 13 November, but satellite imagery showed a plume drifting 250 km NE. A gray plume rose 6.5 km above the crater on 14 November. That same day a plume identified in satellite imagery drifted 200 km NW and ash clouds drifted from the SE to the NE. The Alert Level remained at Red.
Geologic Background. The Puyehue-Cordón Caulle volcanic complex (PCCVC) is a large NW-SE-trending late-Pleistocene to Holocene basaltic-to-rhyolitic transverse volcanic chain SE of Lago Ranco. The 1799-m-high Pleistocene Cordillera Nevada caldera lies at the NW end, separated from Puyehue stratovolcano at the SE end by the Cordón Caulle fissure complex. The Pleistocene Mencheca volcano with Holocene flank cones lies NE of Puyehue. The basaltic-to-rhyolitic Puyehue volcano is the most geochemically diverse of the PCCVC. The flat-topped, 2236-m-high volcano was constructed above a 5-km-wide caldera and is capped by a 2.4-km-wide Holocene summit caldera. Lava flows and domes of mostly rhyolitic composition are found on the E flank. Historical eruptions originally attributed to Puyehue, including major eruptions in 1921-22 and 1960, are now known to be from the Cordón Caulle rift zone. The Cordón Caulle geothermal area, occupying a 6 x 13 km wide volcano-tectonic depression, is the largest active geothermal area of the southern Andes volcanic zone.