Volcán Copahue is an elongated composite cone constructed along the Chile-Argentina border within the 6.5 x 8.5 km wide Trapa-Trapa caldera that formed between 0.6 and 0.4 million years ago near the NW margin of the 20 x 15 km Pliocene Caviahue (Del Agrio) caldera. The eastern summit crater, part of a 2-km-long, ENE-WSW line of nine craters, contains a briny, acidic 300-m-wide crater lake (also referred to as El Agrio or Del Agrio) and displays intense fumarolic activity. Acidic hot springs occur below the eastern outlet of the crater lake, contributing to the acidity of the Río Agrio, and another geothermal zone is located within Caviahue caldera about 7 km NE of the summit. Infrequent mild-to-moderate explosive eruptions have been recorded since the 18th century. Twentieth-century eruptions from the crater lake have ejected pyroclastic rocks and chilled liquid sulfur fragments.
The broad glacier-covered summit of Volcán Copahue along the Chile/Argentina border is seen from the SE with conical Callaqui volcano in the distance. The lake-filled active crater of Copahue (lower center) has been the site of historical eruptions. The composite cone was constructed along the Chile/Argentina border within an 8-km-wide caldera formed 0.6 million years ago. The eastern summit crater is part of a 2-km-long, ENE-WSW line of nine craters that cuts across the western rim of the caldera.
Photo by Oscar González-Ferrán, 1992 (University of Chile).
Last updated 2019-11-13 12:00:05