Wednesday, May 29, 2013

Copahue Volcano In Chile Raised to Red Alert

Chile's Copahue Volcano, which also shares its summit with neighboring Argentina, has been raised to alert level "RED" by Southern Andes Volcanological Observatory (OVDAS) after strong eruptive activity today. The volcano became restless a couple of weeks ago when tremor and minor steam, gas, and ash emissions were observed. A Facebook statement from the Smithsonian GVP stated:

"...Red Alert status was maintained and increased seismicity was reported in yesterday's report by the Southern Andes Volcanological Observatory (OVDAS). Approx 130 EQ were recorded per hour (mostly hybrid but some spasmodic tremor); these were shallow events. Last year the seismic network was expanded to include a new station (the 3rd in the network) located across Argentina's border, expanding early warning capabilities. (http://www.perfil.com/ediciones/ciencia/-201212-740-0057.html) Dated 28 May 2013, this photo was available from Argentina's publication "La Voz" (http://www.lavoz.com.ar/noticias/sucesos/exodo-pobladores-ante-posible-erupcion-volcan-copahue#). — at Caviahue-Copahue."

Copahue volcano is characterized by the GVP here:

"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."



Image posted by Smithsonian GVP showing ash eruption from Copahue on May 28th.
The last eruption of Copahue volcano was in the year 2000, so it has not erupted for about 13 years or so.

Chile lies along the so-called "Ring of Fire" and is prone to frequent eruptive activity from its many active volcanoes. 



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