Yellowstone's famous caldera, which last erupted more than 640,000 years ago, can lay claim as North America's most well-known supervolcano.
But it isn't the continent's largest. A more ancient one found near the small southwestern Utah town of Enterprise was about 30 times bigger.
Aspects of the geological landscape southern Utah is famous for – Pine Mountain, Veyo volcano and lava flows – come from volcanic activity in the area, all stemming from the supervolcano Wah Wah Springs.
But Wah Wah Springs' week-long explosion happened a long time ago. About 30 million years ago. Should you be concerned about supervolcanoes and volcanic activity in this part of the United States?
Wah Wah Springs and Yellowstone
Yellowstone still has frequent volcanic activity, and some people say we’re overdue for another big one (which if you’re talking in the span of thousands of years, maybe), according to local scientist Ron Smith.
“Yellowstone has gotten a lot of publicity because of the severity of a supervolcano and the effect it would have on the earth," Smith, a former university professor in California and now SunRiver resident, said at a lecture at Dixie State University on Monday. "We cannot say that Yellowstone is overdue. ... It is probably going to blow again, but it could well be 500,000 years from now or a week from Tuesday."
According to the United States Geological Survey, the probability of another supervolcanic event in Yellowstone in the next few thousand years is "exceedingly low."
Wah Wah Springs released 30 times more ash and debris than the infamous Yellowstone explosion, though, Smith said. Compared with more recent volcanic events, it was 5,000 times larger than the eruption of Mount St. Helens in 1980.
Brigham Young University researchers found out about Wah Wah Springs only in 2013. Erosion can make supervolcanoes hard to find, but by discovering and measuring lava flows in the region, researchers were able to map out Wah Wah Springs on the border of Utah and Nevada, near Enterprise.
Deposits from the eruption are 13,000 feet thick in some areas of southern Utah, and its remains can be found as far away as Nebraska, researcher Eric Christiansen said in a news release in 2013. "Imagine the devastation – it would have been catastrophic to anything living within hundreds of miles," he said.
Dormant but not extinct
During his lecture, Smith talked about the risks that come with volcanic activity — ash, climate change, lahar and pyroclastic flow.
Ash is typically what people picture when a volcano goes off, but Smith pointed out that it's not like smoke coming from a burning campfire. It's made up of tiny pieces of rocks and minerals, which can damage lungs if inhaled.
Big fluctuations in climate, like when we had ice ages and extreme weather jumps, can oftentimes be linked to volcanoes, according to Smith.
"Volcanic ash is not only dangerous to breathe, but it also produces climate change that has a wide-range effect on human habitation of the earth," Smith said.
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Lahar and pyroclastic flow are two lesser-known effects of volcanoes but are worth noting. Lahar is the mudflow that comes from the slopes of the volcano. Pyroclastic flow is the fast-moving hot gas and matter, which is what BYU researchers studied when finding Wah Wah Springs.
There are active volcanoes around the world, some of them near heavily populated areas. But the Wah Wah Springs region is considered dormant, even though there’s always a chance for more volcanic action, Smith said.
"This area is considered to be dormant, but not extinct at this time," Smith said. "The more severe a volcanic eruption, the more rare it turns out to be. And the less severe, the more common it turns out to be, which is very fortunate for us."
Follow Lexi Peery on Twitter: @LexiFP.
This article originally appeared on St. George Spectrum & Daily News: Supervolcano in Southern Utah is 30 times larger than Yellowstone