Tuesday, May 07, 2013

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PHREATIC ERUPTION AT MAYON VOLCANO


Source: Facebook

A phreatic eruption, also called a phreatic explosion or ultravulcanian eruption, occurs when magma heats ground or surface water. The extreme temperature of the magma (anywhere from 500 to 1,170 °C (932 to 2,138 °F)) causes near-instantaneous evaporation to steam, resulting in an explosion of steam, water, ash, rock, and volcanic bombs.[1] At Mount St. Helens, hundreds of steam explosions preceded a 1980 plinian eruption of the volcano.[1] A less intense geothermal event may result in a mud volcano. In 1949, Thomas Jaggar described this type of activity as a steam-blast eruption. [Source: http://en.wikipedia.org/wiki/Phreatic_eruption]

Mayon Volcano this morning. Usually, for us in Albay, an eruption of Mayon is spectacular. Watching the fireworks in the nights is amazing. Tourism also improves during the eruption. Of course, we wish no casualties. Usually there aren't except when there's heavy rain or typhoon where it affects the flow of lava. Today's case, unfortunately, they have casualties.  

Source: GMA

Despite the casualties, Mayon Volcano's May 7 eruption was relatively mild in its 390-year recorded history, the Philippine Institute of Volcanology and Seismology (Phivolcs) said Tuesday, mere hours after the mountain's latest explosion. 

No one might have died if climbers were not near the peak at the time of the sudden "phreatic eruption," a steam blast caused by hot magma deep in the earth. The climbers reportedly died in a hail of large rocks. The explosion caught the country's vulcanologists by surprise. But they said there was no indication of a follow-up eruption. 

The iconic Bicol landmark has erupted at least 50 times in the 390-year period between 1616 and 2006, according to Phivolcs.
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