Yellowstone supervolcano ‘even more colossal’

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The supervolcano that lies beneath Yellowstone National Park in the US is far larger than was previously thought, scientists report.

A study shows that the magma chamber is about 2.5 times bigger than earlier estimates suggested.

A team found the cavern stretches for more than 90km (55 miles) and contains 200-600 cubic km of molten rock.

The findings are being presented at the American Geophysical Union Fall Meeting in San Francisco.

Prof Bob Smith, from the University of Utah, said: “We’ve been working there for a long time, and we’ve always thought it would be bigger… but this finding is astounding."

If the Yellowstone supervolcano were to blow today, the consequences would be catastrophic.

The last major eruption, which occurred 640,000 years ago, sent ash across the whole of North America, affecting the planet’s climate.

 

Written By: Rebecca Morelle
continue to source article at bbc.co.uk

5 COMMENTS

  1. A study shows that the magma chamber is about 2.5 times bigger than earlier estimates suggested.

    A team found the cavern stretches for more than 90km (55 miles) and contains 200-600 cubic km of molten rock.

    The USA (and the world) has just found that the time bomb they are sitting on is a lot bigger than previously thought!
    Who needs to look for a doomsday weapon?

  2. YIKES!!

    I saw a few documentaries on the Yellowstone caldera a few years back. The estimated size at the time was already staggering. And now they’re saying it’s more than TWICE that size??? That’s truly terrifying…

    • In reply to #2 by NearlyNakedApe:

      YIKES!!

      When there is a terrorist bomb, they evacuate the street! – Anyone heard of plans to evacuate a continent (or a planet)?

      http://ngm.nationalgeographic.com/print/2009/08/yellowstone/achenbach-text

      The “hot spot” responsible for the Yellowstone caldera has erupted dozens of times in the past, going back some 18 million years. Since the hot spot is rooted deep in the Earth, and the tectonic plate above it is moving southwest, ghostly calderas from the more ancient explosions are strung out like a series of gigantic beads across southern Idaho and into Oregon and Nevada, the subsequent lava flows forming the eerie moonscapes of the Snake River Plain.

      The last three super-eruptions have been in Yellowstone itself. The most recent, 640,000 years ago, was a thousand times the size of the Mount St. Helens eruption in 1980, which killed 57 people in Washington. But numbers do not capture the full scope of the mayhem. Scientists calculate that the pillar of ash from the Yellowstone explosion rose some 100,000 feet, leaving a layer of debris across the West all the way to the Gulf of Mexico. Pyroclastic flows—dense, lethal fogs of ash, rocks, and gas, superheated to 1,470 degrees Fahrenheit—rolled across the landscape in towering gray clouds. The clouds filled entire valleys with hundreds of feet of material so hot and heavy that it welded itself like asphalt across the once verdant landscape. And this wasn’t even Yellowstone’s most violent moment. An eruption 2.1 million years ago was more than twice as strong, leaving a hole in the ground the size of Rhode Island. In between, 1.3 million years ago, was a smaller but still devastating eruption.

      Each time, the whole planet would have felt the effects. Gases rising high into the stratosphere would have mixed with water vapor to create a thin haze of sulfate aerosols that dimmed sunlight, potentially plunging the Earth into years of “volcanic winter.” According to some researchers, the DNA of our own species may pay witness to such a catastrophe around 74,000 years ago, when a supervolcano called Toba erupted in Indonesia. The ensuing volcanic winter may have contributed to a period of global cooling that reduced the entire human population to a few thousand individuals—a close shave for the human race.

      For all their violence, the supervolcanoes have left little behind beyond a faintly perceptible sense of absence. The Yellowstone caldera has been eroded, filled in with lava flows and ash from smaller eruptions (the most recent was 70,000 years ago) and smoothed by glaciers. Peaceful forests cover any lingering scars. The combined effect makes it almost impossible to detect, unless you’ve got a good eye, like Doane had, or a geologist whispering in your ear.

    • In reply to #3 by Blasphemyman:

      Do the Yellowstone Park people use geothermal energy?

      I think there are only a few park rangers resident in the winter. The influx of humans is seasonal so it is probably not worthwhile on any large scale.

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