Report on Copahue (Chile-Argentina) — 8 October-14 October 2014
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 8 October-14 October 2014
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2014. Report on Copahue (Chile-Argentina). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 8 October-14 October 2014. Smithsonian Institution and US Geological Survey.
37.856°S, 71.183°W; summit elev. 2953 m
All times are local (unless otherwise noted)
SERNAGEOMIN reported that two explosions from Copahue’s El Agrio Crater occurred at 0752 and 1349 on 11 October, and generated dark gray ash plumes that rose at most 3.6 km above the crater. Some minor explosions were detected after the second explosion. Incandescence in the vicinity of the crater was observed at night. The Alert Level was raised to Orange. Cameras near the volcano recorded dark gray ash plumes rising to a maximum height of 1.9 km and drifting 35 km NE on 12 October, 2.2 km and drifting E on 13 October, and 0.4 km and drifting E on 14 October. Minor explosions continued to be detected.
Geologic Background. 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 at Copahue since the 18th century. Twentieth-century eruptions from the crater lake have ejected pyroclastic rocks and chilled liquid sulfur fragments.