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Yellowstone Supervolcano Even Bigger Than We Realized
The Washington Post reports that the "supervolcano" beneath Yellowstone National Park (which, thankfully, did not kill us all in 2004, or in 2008 ) may be more dangerous when it does erupt than anyone realized until recently. Scientists have today published a paper documenting their discovery of an even
larger, deeper pool of magma below the already huge reservoir near the surface. From the article:
On Thursday, a team from the University of Utah published a study, in the journal Science, that for the first time offers a complete diagram of the plumbing of the Yellowstone volcanic system.
The new report fills in a missing link of the system. It describes a large reservoir of hot rock, mostly solid but with some melted rock in the mix, that lies beneath a shallow, already-documented magma chamber. The newly discovered reservoir is 4.5 times larger than the chamber above it. There's enough magma there to fill the Grand Canyon. The reservoir is on top of a long plume of magma that emerges from deep within the Earth's mantle. ...
“This is like a giant conduit. It starts down at 1,000 kilometers. It's a pipe that starts down in the Earth," said Robert Smith, emeritus professor of geophysics at the University of Utah and a co-author of the new paper. ... The next major, calderic eruption could be within the boundaries of the park, northeast of the old caldera. “If you have this crustal magma system that is beneath the pre-Cambrian rocks, eventually if you get enough fluid in that system, enough magma, you can create another caldera, another set of giant explosions," Smith said. "There’s no reason to think it couldn’t continue that same process and repeat that process to the northeast.”
It's been an oil producing area for over 100 years
Yes, it could cause what we'd think of as a "nuclear winter". Which is really how it would do most of it's global damage. The ashfall would also be off the charts, but likely confined to North America.
Basically take the entire Yellowstone park, dig out every cubic centimeter of dirt and rocks from the surface down to the lava reservoir and just throw all of that into the stratosphere. All at once. Of course you don't want to be in the radius where the heavy stuff starts coming down on you, and that will probably be a number of entire states under significant debris.
The rest of the world will merely need to deal with the sun being blotted out for a few years. This is what happened when Mount Tambora erupted which was only a "normal" VEI-7 eruption. http://en.wikipedia.org/wiki/1...
Spoilers: The Year Without A Summer (1816) http://en.wikipedia.org/wiki/Y...
A supervolcano is VEI-8+
Note that they are supposed to be 1/10,000ish year events. Thereabouts, that seems sort of high. While Yellowstone might not go off any time soon, there are other places that might much sooner.
The Toba eruption about 74,000 years ago is thought to have caused a genetic bottleneck in humans were we were cut down to the mere tens of thousands of people in the entire world.
Toba being principally responsible for this bottleneck is disputed, but it should also be pointed out that humans at that time were fairly mobile, so their strategy for survival would probably not be possible for most of us. Our ancestors at the time didn't rely on agriculture and with humans only in the millions in population, we could have probably foraged and moved.
Humans today... well let's just say that our urban populations would not have the ability to switch hunting grounds.
I'm not sure any of the known calderas are actually thought to be ready to blow in the near future, but Yellowstone was supposed to go off in 600,000ish year intervals and I believe we're overdue. It doesn't mean it will go off any time soon, just that it's starting to look like it is time again, assuming that the characteristics of the lava reservoir are similar to last time.
The most recent VEI8 was Taupo, only 24,500 years ago. Previous was Toba, 74k years ago, Neither was an extinction event.
We've had quite recent VEI7: Tambora (1815), Samalas (1257), Taupo {again) (180) and Thera (1620BC). None of these was remotely an extinction event (though it probably sucked to be a Minonan at the time).
If Yellowstone pops at VEI7 it will suck to be near and there will be a long, cold winter or two, worldwide. VEI8 will be worse, which is to say very bad. But the Southern Hemisphere should be slightly better. Note that the Aborigines have been in Australia for over 40,000 years, so they survived the nearby Taupo bang.
I thought it was widely known that when Yellowstone finally does go up, that will be an extinction-level event. Most of the planet will become completely uninhabitable for decades.
Not true. We need to remember that there are more than 100 known caldera eruptions of the Yellowstone hotspot as it migrated from eastern Oregon to its present location over the past 16 million years. None of these eruptions, including the big eruption of 2 million years ago, are tied to known global extinction events over this time period.
Sure, if you were a plant or animal with a limited range too close to one of these supervolcano eruptions, you were out of luck, but we don't see global impact over the known lifespan of the hotspot. If it were remotely as bad as you claim, we would have seen some obvious signs of it in the fossil record, which we don't.
Further, why would the Earth's atmosphere become unbreathable? Sure, there's a lot of ash and gases released in a supervolcano eruption. But the Earth's atmosphere is much bigger than that and most of those gases, aside from carbon dioxide and other relatively insoluble gases, would wash out in rain. The remnant that remains in the stratosphere wouldn't have much effect precisely because of how little there is in the stratosphere.
Prepping for this is a joke. No power, no running water, no crops, no breathable air on the surface, for years and years. Your basement shelter won't keep you alive for a month under those conditions.
Enough lead time and you can prep for anything nature throws at you other than universe-scale problems like the heat death of the universe. Maybe even that can be managed successfully though I'm not feeling up to it.