Copahue () is a

stratovolcano A stratovolcano, also known as a composite volcano, is a conical volcano built up by many layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and peri ...

in the

Andes The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S ...

on the border of Bío Bío Region,

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the eas ...

and

Neuquén Province Neuquén () is a province of Argentina, located in the west of the country, at the northern end of Patagonia. It borders Mendoza Province to the north, Rio Negro Province to the southeast, and Chile to the west. It also meets La Pampa Provinc ...

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the List of South American countries by area, second-largest ...

. There are nine

volcanic crater A volcanic crater is an approximately circular depression in the ground caused by volcanic activity. It is typically a bowl-shaped feature containing one or more vents. During volcanic eruptions, molten magma and volcanic gases rise from an und ...

s along a line, the easternmost of which is historically the most active, and contains a 300 m (1000 ft) wide

crater lake Crater Lake ( Klamath: ''Giiwas'') is a volcanic crater lake in south-central Oregon in the western United States. It is the main feature of Crater Lake National Park and is famous for its deep blue color and water clarity. The lake partly fill ...

with a pH ranging between 0.18 and 0.30. Eruptions from this crater lake have ejected

pyroclastic rock Pyroclastic rocks (derived from the el, πῦρ, links=no, meaning fire; and , meaning broken) are clastic rocks composed of rock fragments produced and ejected by explosive volcanic eruptions. The individual rock fragments are known as pyrocl ...

s and chilled liquid

sulfur Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formul ...

fragments. Although the lake emptied during the 2000 eruption, it later returned to its previous levels. ''Copahue'' means "sulphur waters" in

Mapuche The Mapuche ( (Mapuche & Spanish: )) are a group of indigenous inhabitants of south-central Chile and southwestern Argentina, including parts of Patagonia. The collective term refers to a wide-ranging ethnicity composed of various groups who s ...

. Copahue sits on a

basement A basement or cellar is one or more Storey, floors of a building that are completely or partly below the storey, ground floor. It generally is used as a utility space for a building, where such items as the Furnace (house heating), furnace, ...

sedimentary Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...

and volcanic rocks ranging in age from

Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', ...

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58caldera A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcano eruption. When large volumes of magma are erupted over a short time, structural support for the rock above the magma chamber is ...

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). The modern caldera formed 0.6 to 0.4 Ma, and produced large

pyroclastic flows A pyroclastic flow (also known as a pyroclastic density current or a pyroclastic cloud) is a fast-moving current of hot gas and volcanic matter (collectively known as tephra) that flows along the ground away from a volcano at average speeds of b ...

, extending up to 37 km from the volcano. Eruption of Copahue Volcano, Argentina-Chile 12-22-2012

The modern structure is an elongated

shield volcano A shield volcano is a type of volcano named for its low profile, resembling a warrior's shield lying on the ground. It is formed by the eruption of highly fluid (low viscosity) lava, which travels farther and forms thinner flows than the more vi ...

, with a maximum thickness of 22 km and a minimum of 8 km. It has erupted ten times since 1900, most recently in March 2016. 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. CopahueCraterLake

References

Bibliography

* (in Spanish; also includes volcanoes of Argentina, Bolivia, and Peru) *

External links

USGS Geologic Map of the Copahue Volcanics
{{Authority control Active volcanoes Volcanoes of Biobío Region Volcanoes of Neuquén Province Stratovolcanoes of Chile Stratovolcanoes of Argentina Subduction volcanoes Volcanic crater lakes Argentina–Chile border International mountains of South America Mapuche language Pleistocene stratovolcanoes Holocene stratovolcanoes

See also

References

Bibliography

External links