Report on Puyehue-Cordon Caulle (Chile) — 13 July-19 July 2011
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 13 July-19 July 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, 13 July-19 July 2011. Smithsonian Institution and US Geological Survey.
40.59°S, 72.117°W; summit elev. 2236 m
All times are local (unless otherwise noted)
OVDAS-SERNAGEOMIN reported that on 12 and 14 July cameras installed around the Puyehue-Cordón Caulle volcanic complex recorded eruption plumes that rose no higher than 2 km above the Cordón Caulle rift zone and drifted E; weather prevented observations of the plume on 13 July. Seismic activity declined significantly. On 15 July satellite imagery showed a plume drifting 80 km E and seismic signals indicated that lava started to flow again. The effusion rate increased on 16 July, however weather again prevented observations. A light gray plume on 17 July rose 2 km above the crater and was observed in satellite imagery drifting 240 km E. According to a news article, the first plane landed at the airport in Bariloche, about 100 km E, since the airport had closed on 4 June. On 18 July a gray plume rose 5 km above the crater and drifted 150 km NW. Incandescent material observed at night was ejected 500 m above the crater and lava flows continued to be active. 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.