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Earth Science

'Geospeedometer' Confirms Super-eruptions Have Surprisingly Short Fuses (vanderbilt.edu) 67

Science_afficionado writes: Super-eruptions – you know, those gigantic prehistoric volcanic outbursts that throw 100 times more superheated gas, ash and rock into the atmosphere than run-of-the-mill eruptions like Mt. St. Helens — tend to pop-off within a few hundred years after their underground body of magma reaches a high enough proportion of molten rock and low enough proportion of crystallization to become explosive. That's a much shorter time than geologists had thought. That means if the hot spot under Yellowstone, for example, were to turn explosive, then we would only have couple hundred years to prepare for an eruption that could blanket the entire continent with up to 3,600 cubic miles of ash and rock!
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'Geospeedometer' Confirms Super-eruptions Have Surprisingly Short Fuses

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  • The Columbia river gorge in Washington state was carved from a series of cataclysmic floods [wikipedia.org], the largest of which carried 13 times the volume of the Amazon river.

    • by Rei ( 128717 ) on Wednesday October 21, 2015 @10:02AM (#50772797) Homepage

      North-flowing rivers in temperate and subarctic northern hemisphere regions are dangerous, as they collect rainwater or meltwater from warmer areas in the south and flow it up into areas that may still be frozen, and thus blocked off by ice dams.

      Here in Iceland we have a related problem but with a different source - volcanic outburst floods (jökulhlaup). Unfortunately ours are still ongoing at regular intervals. We had one about 10-15% the size of the largest Columbia River Gorge floods in the 1800s. And in prehistoric times they've gotten far larger. It's the reason why people get nervous when big subglacial volcanoes like Bárðarbunga start rumbling. The power companies try to calm people down by saying no worries, the dams from which we get most of our power are rated to handle jökulhlaup... but when you look at the size of jökulhlaup they're rated for they're nothing, like 10k m/s or so.

      • the dams from which we get most of our power are rated to handle jÃkulhlaup... but when you look at the size of jÃkulhlaup they're rated for they're nothing, like 10k m/s or so.

        Nothing? I'd be pretty damn impressed with a dam that can handle a flood moving at orbital velocity.

  • by cdrudge ( 68377 ) on Wednesday October 21, 2015 @08:33AM (#50772217) Homepage

    we would only have couple hundred years to prepare for an eruption that could blanket the entire continent with up to 3,600 cubic miles of ash and rock!

    Where did the 3,600 cubic miles of ash and rock figure come from?

    The largest 3 previous explosions of the Yellowstone caldera happened 2m, 630k, and 1.3m years ago releasing an estimated 600, 240, and 67 cubic miles of ash and rock. That's a combined 907 cubic miles, a quarter of what the summary suggests could happen. I can't find that number in the article anywhere. 3600 cubic kilometers converts to approximately 863.7 cubic miles which would be more believable. The largest volcanic eruptions [wikipedia.org] ever believed to happen top out at 8,600 cubic kilometers, ~2063 cubic miles.

    • by khallow ( 566160 ) on Wednesday October 21, 2015 @09:02AM (#50772369)

      Where did the 3,600 cubic miles of ash and rock figure come from?

      It's probably based on the size of the magma chambers underneath Yellowstone which are much larger in volume than the eruptions from Yellowstone.

      While you are currently right about the estimated size of known, possibly single volcanic eruptions, it's worth noting that ongoing volcanic eruptions can be much larger, such as the Siberian Traps, which are thought to originally have been as high as seven million cubic km of lava over a million year period.

      • by zdavek ( 75457 )

        3600 cubic miles is roughly 10 percent of the mass of earth. If that much erupted I think nothing would exist afterwards, especially N Am. Earth's orbit would probably be changed if there was an eruption that size.

        • 3600 cubic miles is roughly 10 percent of the mass of earth.

          Huh?

          3600 is a little less than 16 cubed (2^12 = 4096). So it's a volume contained in a cube less than 16 miles on a side.

          That's a lot less than 10% of the volume of the Earth.

        • wait, what? How small do you think the earth is! I can only guess that you think 3600 cubic miles is the volume of a cube of side 3600 miles. Usually this is meant to be the volume. so, for example, the volume of a cube of side 15 miles is around that much.
        • 3600 cubic miles is roughly 10 percent of the mass of earth.

          Perhaps you're thinking "3600 miles cubed" instead of "3600 cubic miles". They're not the same thing.

        • by Anonymous Coward

          3600 cubic miles is roughly 10 percent of the mass of earth.

          You might be confusing the term "3600 cubic miles" with "3600 miles cubed".

          The standard interpretation of "3600 cubic miles" is that it's the volume that results when you take one cubic mile and multiply it by 3600.

          The standard interpretation of "3600 miles cubed" is that it's the volume of a cube that is 3600 miles long on each side.

          There is at least 10 orders of magnitude in difference between these two interpretations.

    • by BradleyUffner ( 103496 ) on Wednesday October 21, 2015 @09:51AM (#50772701) Homepage

      we would only have couple hundred years to prepare for an eruption that could blanket the entire continent with up to 3,600 cubic miles of ash and rock!

      Where did the 3,600 cubic miles of ash and rock figure come from?

      The largest 3 previous explosions of the Yellowstone caldera happened 2m, 630k, and 1.3m years ago releasing an estimated 600, 240, and 67 cubic miles of ash and rock. That's a combined 907 cubic miles, a quarter of what the summary suggests could happen. I can't find that number in the article anywhere. 3600 cubic kilometers converts to approximately 863.7 cubic miles which would be more believable. The largest volcanic eruptions [wikipedia.org] ever believed to happen top out at 8,600 cubic kilometers, ~2063 cubic miles.

      It was precisely calculated by taking the realistic number and adding the "scare multiplier" to it in order to increase page views.

  • I've seen worse.

  • I had a super-eruption recently. Let's just say Daisy Ridley was a fiiiiiiine choice for Star Wars.

  • we would only have couple hundred years to prepare for an eruption

    I think you meant "we would only have a couple hundred years to sit on our asses denying that an eruption could ever happen, and even if it did erupt there's nothing we could do about it anyhow".

    • by khallow ( 566160 )

      I think you meant "we would only have a couple hundred years to sit on our asses denying that an eruption could ever happen, and even if it did erupt there's nothing we could do about it anyhow".

      Why would anyone bother? The eruption wouldn't force us to curb our evil industrial activities so there's nothing there to turn it into the moralistic wankfest that is climate change.

      • Re: (Score:2, Funny)

        by gtall ( 79522 )

        As opposed to the wankfest that is climate change denial, possibly? Relax, Jesus will save us...err...anyone got his number, just in case?

        • by khallow ( 566160 )

          As opposed to the wankfest that is climate change denial, possibly?

          Yes. I think that's generally portrayed as reactionary.

    • by Matheus ( 586080 )

      Plus the "there's nothing we could do about it anyhow" has a bit of truth. I'm all for novel solutions (like what Spock did to the volcano in New Trek 2) but for our current reality the only solutions amount to "Colonizing other planets" or other such relocation efforts (Sky, underground in "safe" parts of the world, etc). We're hopefully already working on #1 albeit at a snail's pace so a couple hundred years year's warning may be just the right amount to actually have some population out there. The reali

      • Why not just stockpile a years worth of food and continue on? It will get a little cold, but nothing we couldn't deal with.

  • but there's probably enough energy in the Yellowstone magma chambers to 100% power all our (humanity's - the world's) energy requirements for absolutely everything we do. Tapping it fully, MAYBE we could keep it from getting any hotter. Suspicious we could not construct enough heat sinks to actually cool it at all, its too big.

  • Yellowstone is one... are there any others? How many? Where?

    • http://www.businessinsider.com... [businessinsider.com]

      I wouldn't want to deal with the Meter or so of ash, but in most of the country it is something that could be dealt with. It is the global crash of agriculture for however long that would be a bad thing, but that we could prepare for as well.

  • bleb - n.

    a small blister on the skin.

    a small bubble in glass or in a fluid.

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