There’s a supervolcano under Yellowstone National Park in Wyoming. Scientists just figured out that the magma chamber beneath the park is bigger – much, much bigger – than they ever realized. One day an eruption will come. When it does, the scientists say the magnitude of impact will be “a global event.”
The magma chamber is about 20 miles wide, 55 miles long, and goes as deep as three to nine miles below the Earth’s surface, according to researchers who presented these findings recently to the American Geophysical Union’s fall meeting in San Francisco. That’s roughly two and a half times as big as previously thought. It’s about 162 square miles of red hot molten magma.
“We’ve been working there for a long time, and we’ve always thought it would be bigger… but this finding is astounding,” said University of Utah Prof. Bob Smith.
What Exactly Would Happen if the Yellowstone Supervolcano Blew Today?
Judging by what happened the last time this particular volcano had a major eruption, the news is not good. About 640,000 years ago, the biggest known eruption from this volcano spewed ash over all of North America. Remember Mount St. Helens in 1980? That was baby stuff. Multiply that effect by about 2,000 to get an idea of the possible devastation.
To be sure, we wouldn’t see rivers of lava extending coast to coast. The damage of critical concern, U.S. Geological Survey (USGS) geologist Jake Lowenstern told io9.com, will result from a deep blanket of ash and pumice falling from the skies.
A “super eruption” would throw volcanic material throughout a 500 mile radius of the volcano. Envision a four-inch deep cloak of ash, smothering and polluting our midwestern farms and rivers. No farms, no food, as the saying goes. Cleaning it up would be a monstrous effort.
While the United States would be at the epicenter of such a disaster, the rest of the world would undoubtedly feel the effects as well.
“It would be a global event,” said the study’s lead author, University of Utah’s Jamie Farrell. “There would be a lot of destruction and a lot of impacts around the globe.”
“All this material that is shot up in the atmosphere would eventually circle the earth and would affect the climate throughout the world,” Farrell told the BBC.
Is an Eruption Imminent? Should You Step Up Completion of Your Bucket List?
Don’t get worked up about this news, say researchers. This volcano, or “caldera” as it is more accurately known, has only experienced a super eruption three times – 2.1 million years ago, 1.3 million years ago and 640,000 years ago. Give or take, experts think this volcano has a big eruption every 700,000 years or so.
On the other hand, that 700,000 estimate is something of a wild guess, really.
“You can only use the time between eruptions [to work out the frequency], so in a sense you only have two numbers to get to that 700,000 year figure,” Prof. Smith told the BBC. ”How many people would buy something on the stock market on two days of stock data?”
When a super eruption is finally ready to happen, scientists say we’d have lots of warning signs. First we’d see earthquakes, which are necessary to break down the rocks that keep the magma under the ground.
Next we’d likely see blasts of lava and hot gas from fissures ripping open within a few miles of the volcano. These would cause the magma reservoir to drain and trigger the collapse of the caldera into a huge 1,500 square mile sinkhole.
The Volcano is Breathing
Fortunately, as with all volcanos, many smaller eruptions have been releasing internal pressure in the magma chamber over time.
“Calderas are big and hot, so they don’t break very easily and they just move up and down. It’s the way heat and gas get out of these deep systems — the system breathes,” Lowenstern said.
As National Geographic notes, the Yellowstone volcano is shifting and “breathing” all the time:
The park roils with geysers, fumaroles, mud volcanoes, and other hydrothermal activity. Half the geysers on the planet are in Yellowstone. The hydrothermal features change constantly in temperature and behavior, with new ones popping up in the forests, spewing clouds of steam visible from airplanes, exuding vapors that have been known to kill bison on the spot.
Most likely, none of us will need to worry about a super eruption in our lifetimes, or even within our great-great-great grandchildren’s lifetimes. One day, though, someone will need to worry. The Yellowstone supervolcano is sleeping, but the slumbering giant will awaken one day. The Earth won’t be the same when it does.
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