Thursday, May 08, 2008

Chilean Volcano Erupts After 9,000 Quiet Years



It could now erupt for weeks or months. Chaiten, the town closest to the volcano has been evacuated. Places to the east, such as Futaleufu and areas in Argentina - in the path of the plume have also had to evacuate. There is 6" of ash covering some areas.

Chile sits on the Nazca tectonic plates and is one of the most active volcanic areas. 20 of it's 100 volcanoes are active at any given time.
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This is from Times online about "Volcanic Lightning":

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The photo of lightning bursting out during a volcanic eruption in Chile, above, was a truly awesome sight. Although the picture seemed to show a thunderstorm colliding with the cloud of volcanic ash, it actually showed a marvellous phenomenon known as volcanic lightning.

Usually, lightning is sparked off by countless tiny pieces of ice inside a turbulent thundercloud banging into one another. Each collision generates static electricity, rather like a balloon rubbed on a jumper.

Eventually, the entire cloud turns into a colossal battery and the electricity is discharged as a gigantic spark – lightning.

A recent theory pictures the volcanic cloud as a “dirty thunderstorm”.

As fragments of rock and ash particles shoot upwards in the towering plume, they hit each other and the friction generates static charges that creates lightning bolts. And as the volcanic cloud cools off high up in the atmosphere, water from the eruption turns to ice and adds extra punch to the electrical storm.

Smaller lightning bolts also have been discovered bursting out from the mouth of a volcano’s crater as the gases and ash explode, but what generates this lightning is not known.

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