Copahue

Copahue
Copahue Volcano photographed from space
Highest point
Elevation	2,997 m (9,833 ft)[1]
Coordinates	37°51′S 71°10′W / 37.850°S 71.167°W / -37.850; -71.167[1]
Geography
Copahue Argentina-Chile
Location	Neuquén Province,  Argentina Bío Bío Region,  Chile
Parent range	Andes
Geology
Mountain type	Stratovolcano
Last eruption	January 6, 2016[1]

Copahue (Spanish pronunciation: [koˈpawe]) is a stratovolcano in the Andes on the border of Bío Bío Region, Chile and Neuquén Province, Argentina. There are nine volcanic craters along a 2 km (1.2 mi) line, the easternmost of which is historically the most active, and contains a 300 m (1000 ft) wide crater lake with a pH ranging between 0.18 and 0.30.^[2] Eruptions from this crater lake have ejected pyroclastic rocks and chilled liquid sulfur fragments.^[1] Although the lake emptied during the 2000 eruption, it later returned to its previous levels. Copahue means "sulphur waters" in Mapuche.^[3]

Copahue sits on a basement of sedimentary and volcanic rocks ranging in age from Eocene to Pliocene.^[2] The modern volcano sits in a volcanically active area, with a caldera from the Pliocene, measuring 20 km by 15 km, lying to the east of Copahue. The modern volcano became active roughly 1.2 million years ago (Ma).^[2] The modern caldera formed 0.6 to 0.4 Ma, and produced large pyroclastic flows, extending up to 37 km from the volcano.^[2]

The modern structure is an elongated shield volcano, with a maximum thickness of 22 km and a minimum of 8 km.^[2] It has erupted ten times since 1900, most recently in March 2016.^[1][3][4] On 27 May 2013, it was reported that a red alert had been issued and the evacuation of around 2,000 people was to begin.^[5]