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

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!

Comments

Where did that 3600 cubic miles figure come from?

[cdrudge]

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 ever believed to happen top out at 8,600 cubic kilometers, ~2063 cubic miles.

Re:Geology sometimes moves VERY quickly

[Rei]

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.