 Last year, 72 volcanoes erupted around the world -- that's a lot of fire, and slightly above average. So far 2009 looks like it's off to a fast start, too, with Mount Redoubt letting loose in Alaska, Japan's Mount Asama raining ash on Tokyo and an undersea volcano in Tonga breaching the surface and growing an island. But none of these is likely to break into our list of Top 10 Volcanoes in Geologic History. Most of these come with signs that read "Danger: Keep Back at Least One Continent." But if this list of past catastrophes teaches us anything, it's that the biggest, baddest volcanoes can erupt anywhere and at any time. And they will again -- it's just a matter of when. 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 things go off, so it's probably a good thing we've never seen one in action. Credit: Larry O'Hanlon |
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