Friday, 22 March 2013

Eruptive activity on Mount Sabancaya.

Mount Sabancaya is a 5967 m stratovolcano (cone shaped volcano) located on a saddle between the older, and larger Hualca Hualca and Ampato, neither of which has been active in historic times. The three volcanoes are located in the Andes of southern Peru. Eruptions were first recorded on Sabacnya by Europeans in 1595, and the volcano is likely to have been intermittently active prior to this. The volcano erupted a number of times in the eighteenth century, then remained quiet until 1986, since when it has undergone six bouts of explosive eruption.

On 15 January 2013 a small plume was seen over Sabancaya. This was seen intermittently till 22 February when the mountain began a phase of extreme tectonic activity, with 536 Earthquakes in two days, accompanied by a plume rising 100 m above the summit of the volcano. This caused damage to eighty houses in the proximity, and lead to a partial evacuation of the immediate area. Plumes continued till 6 March, rising as high as 1 km above the volcano, though these were apparently fumarolic (gaseous), since they left no ash deposits. Such fumarolic emissions are generally made up of carbon dioxide, water vapor and sulphur dioxide. There were at least another 400 Earthquakes during the first week of March.

Plume emerging from Mount Sabancaya in February 2013. Redacción mulera.

The Volcanoes of the Andes are fed by the subduction of the Nazca Plate, which underlies the southeast Pacific, beneath the South American continent. As the plate sinks into the Earth it is heated be the friction and the heat of the planet's interior, causing it to partially melt. Some of the melted material then rises through the overlying South American Plate, fueling the volcanoes of the Andes.


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