Friday, September 20, 2013

126.3 - And Another Thing: world's largest volcano found

And Another Thing: world's largest volcano found

As I said at the top of the show, this week we're going to take something of a break from politics, so the rest of the show is going to be devoted to one of our occasional features; it's called And Another Thing and it's about some cool science stuff.

The first thing to tell you about is that the world's largest volcano has been found under the Pacific Ocean. It's called Tamu Massif and the size of this volcano dwarfs Mauna Loa in Hawai'i, which was previously thought to be the largest. In fact, this volcano is only 25% smaller than Olympus Mons on Mars, which is the largest volcano in the entire Solar System.

One of the reason researchers had trouble finding it is that it's only about two and a-half miles high. Apparently the way these things erupt is that they erupt very slowly and the lava spreads out very gradually, resulting in a low, broad, field. So it's only two and a-half miles tall but it's 400 miles wide. This is actually bigger in area than the state of New Mexico.

Apparently the last time it erupted was about 144 million years ago; it's been extinct since then. But it's a class of volcano that apparently was not recognized before. There are these areas called oceanic plateaus - they are just sort of rises in the ocean - and geologists are starting to realize that yeah, these are actually old volcanos. It's just that the flow is spread out over a large area. So finding out about Tamu Massif may help then understand better how these kinds of things form.

These oceanic plateaus are the largest outflows of lava on Earth and they actually have been linked to mass extinctions and climate change, so they are a significant thing.

By the way, in case you're wondering (as I would be), this volcano was never above the surface. It's been hidden because it sits on a thin portion of the Earth's crust called the lithosphere, which can't support the weight of the volcano, so it the volcano was all packed up and tall, it would just sink back down again.

It's peak is now about 6500 feet, nearly 2000 meters, below the ocean surface.


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