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Mount St. Helens, Washington, USA

TOP 10 VOLCANOES IN GEOLOGIC HISTORY

10. Ontong-Java Plateau, South Pacific.

This is the biggest volcano you've never heard of.

When it erupted 125 million years ago, it covered a region of the South Pacific Ocean the size of Alaska with basalt, in some places as much as 30 kilometers thick. It was so big, the eruption itself is thought to have lasted 6 million years.

Scientists call this type of volcano a large igneous province (LIP). They are highly mysterious, and appear to form when huge amounts of hot magma well up from thousands of miles deep in the mantle, near Earth's core.There's a lot of debate as to whether LIPs erupt in huge explosions, or just ooze out in massive sheets of lava. Either way, mass extinctions have a tendency to occur whenever one of these thing go off, so it's probably a good thing we've never seen one in action.

Mount St. Helens, Washington, USA

May 18, 1980, was a bad day in Washington state.

Silent for over 100 years, the picturesque 9,677-foot peak had by late April grown into a bloated, trembling blister of rock and magma. And like a blister, it popped early on a Sunday morning, rocketing fiery ash out to the north at close to the speed of sound.

The eruption killed 57 people and did almost $3 billion in damage when all was said and done. It also lopped 1,314 feet off the height of the mountain, which was reduced to a smoldering crater.

This was the most deadly volcanic eruption in Unites States history -- and it was just a pipsqueak, really.

 

 


Date: 2015-01-29; view: 871


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