Thursday 23 May 2013

Eruption on Mount Turrialba, Costa Rica.

At about 4.50 am local time (10.50 am GMT) seismic activity (Earthquakes) began around Mount Turrialba, a 3340 m stratovolcano (cone-shaped volcano) in Cartago Province, Costa Rica, which then began to emit stream and CO₂ according to Volcanological and Seismological Observatory of Costa Rica (Oviscori). At about 8.30 (2.30 pm GMT) the volcano began a full eruption, producing a 4 km ash column from two fissures, blowing to the west and southwest and covering local farms with ash. Authorities have recommended an evacuation of the immediate area due to the danger of toxic gas emissions, though many people are apparently unwilling to leave crops and livestock.

Twin ash columns emerging from Mount Turrialba. Oviscori.

Turrialba forms part of the Cordillera Central, a range of volcanic mountains running through central Costa Rica and forming part of the Central American Arc. These volcanoes are fueled by the subduction of the Cocos Plate, which underlies part of the east Pacific Ocean, beneath the Caribbean Plate, on which Central America lies, along the Middle American Trench, which lies off the south coast of the country. As the Cocos Plate is subducted it is gradually melted by the heat and pressure of the Earth's interior, with some more volatile minerals rising through the overlying Caribbean Plate as volcanic magma.

The boundary between the Caribbean and Cocos Plates. Scripps Institution of Oceanography.

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