Worldwide famine. Contaminated water supplies. Mass human extinction. Could
any of these things actually occur if the active supervolcano under Yellowstone was
to suddenly erupt? Here's what science tells us.
Millions of people visit Yellowstone National Park each year for awe-inspiring sights like the Old
Faithful geyser. Attractions like Old Faithful only exist, though, because Yellowstone sits
on top of an active supervolcano. According to the U.S. Geological Survey, or USGS, this supervolcano
is also a ticking geological time bomb that has erupted three times in the past 2.1 million years.
But where there's been an eruption, there's the chance there could be one again. So how
likely is it that the supervolcano under Yellowstone might blow its top,
leading to a super-eruption? And how bad would it be if such a thing was to happen?
As the USGS explains, the Yellowstone supervolcano might erupt soon. Well,
soonish from a geological perspective, meaning sometime in the next couple of thousand years.
Geologists at USGS classify supervolcanoes as a volcanic center with past eruptions
covering at least 240 cubic miles. Meanwhile, super-eruptions from supervolcanoes are defined
as any eruption of at least magnitude 8 on the Volcano Explosivity Index, as Vox explains.
Even though the Yellowstone supervolcano could spew lava,
the USGS assigns a minuscule chance of it happening. As it stands,
there are better odds the world will end from a planet-destroying asteroid.
"Bring it on!"
In other words, with odds being only 1 in 730,000
that the supervolcano might blow, there's no reason to cancel your Yellowstone travel
plans. What might happen, though, is still a fascinating thing to consider.
Even though there's a very small, almost nonexistent chance the supervolcano might erupt,
it's still possible. Should the Yellowstone supervolcano blow up,
the USGS says that it would likely affect the global climate for decades. In the aftermath,
surrounding states like Montana, Idaho, and most of Wyoming would experience pyroclastic
flows — also known as molten lava — along with falling molten rock.
But far more deadly would be the molten ash cloud. This gigantic cloud would cover much of
the American Midwest with a thick blanket of ash. Under that ash, crops, and livestock would suffer,
and as a result, the food supply would diminish. Elsewhere, our streams and rivers
would become temporarily clogged, causing a number of related ecological side effects.
"No more electricity. No more running water. No more everything we took for granted."
The eruption would also cause a caldera to form. A caldera is a depressed area of land
possibly miles wide. In the aftermath, sulfur dioxide would be released into the atmosphere,
which is a trigger for global cooling. So this would further affect the worldwide crop supply.
However, while a Yellowstone eruption would definitely be a cause for concern, it would
be unlikely to cause human extinction. And as the USGS points out, the unlikely eruption would be
predicted months if not years in advance, allowing for proper preparation and damage mitigation.
Though there's next to no chance the Yellowstone supervolcano might erupt in the next couple
thousand years, the area is still closely monitored just to make sure. This chiefly takes
place via the Yellowstone Volcano Observatory, or YVO. Through the YVO website, it's possible
to get real-time information on everything from stream flow and water temperature to earthquake
chances. Volcanic eruptions aside, there are far more common risks at Yellowstone to consider,
such as hydrothermal explosions from a geyser possibly caused by a number of geologic forces.
In 2014, a team of scientists published a paper in the publication, Geochemistry,
Geophysics, Geosystems, which studied the long-term effects of a Yellowstone
super-eruption. As Jacob Lowenstern, who co-authored the study, told Vox:
According to Lowenstern, "small eruptions" — though still rare — are "much,
much more common." The last eruption at Yellowstone, which happened around
70,000 years ago, caused a relatively benign lava flow at Pitchstone Plateau. Lowenstern told Vox: