During 3-8 August, OVDAS-SERNAGEOMIN reported that the eruption continued from the Cordón Caulle rift zone, part of the Puyehue-Cordón Caulle volcanic complex. During 3-4 August a video camera recorded plumes rising 2 km above the crater. Satellite imagery showed plumes drifting 1,000 km NE on 3 August and 700 km SE on 4 August. Cloud cover prevented video camera and satellite observations on 5 August. The next day cloud cover again prevented camera observations, though satellite imagery detected a plume that drifted 250 km E then SE. Plumes that were mostly white rose no higher than 2.5 km above the crater during 7-8 August. Satellite imagery on 7 August detected plumes that drifted 100-200 km SE. The Alert Level remained at Red.

Geological Summary. 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.

Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN)