Yellowstone National Park will celebrate its 151st year in March. It’s a major milestone for America’s oldest national park and an opportunity to set the record straight about the supervolcano that lurks beneath it.
Reports have speculated that if it erupts, the supervolcano would cause a “nuclear winter” and kill nearly 100,000 Americans.
“It’s unfortunate that Yellowstone has this strange reputation that has basically been pushed by these sensationalist documentaries. And there’s a lot of clickbait. And it’s really disappointing,” said Mike Poland, a geophysicist with the U.S. Geological Survey and the scientist-in-charge of the Yellowstone Volcano Observatory.
Poland said all the hype centers around the volcano’s last large eruption 631,000 years ago. It was thousands of times larger than the 1980 eruption of Mount St. Helens, the worst volcanic eruption in U.S. history that killed 57 people. The Mount St. Helens eruption shot 520 million tons of ash across the U.S. and caused complete darkness in parts of Washington state.
“If at some distant point in the future, there was a really large explosive eruption that put a lot of ash and a lot of gas into the stratosphere, then yes, you could see all kinds of really incredible impacts that would stretch globally. But that’s one of those scenarios where the entire magma chamber has to erupt. Far more likely is a lava flow that probably, frankly, will be more of a tourist attraction,” Poland said.
Scientists told Straight Arrow News that the last time an eruption produced lava flow was around 70,000 years ago.
“The kinds of lava flows we get in Yellowstone are not like the ones that we see in a place like Hawaii. They’re not these sheets of molten red rock that spread out over the landscape. Instead, these sort of thick piles of rock or rubble move slowly across the landscape. It’s the kind of thing you could walk away from pretty easily. But anything that it touches, anything that it comes into contact with, will be destroyed,” Poland said.
It’s widely believed that there is only 16 to 20% of melted rock in Yellowstone’s magma reservoirs. That is well below the threshold needed to trigger an eruption, which is about 35 to 50%. These numbers give scientists reason to believe the system is mostly solid.
Plus, Yellowstone doesn’t sit on an ocean plate like the other active volcanoes in the world.
“Yellowstone is the only feature that’s beneath a continental plate. And that makes it quite different because of the continental plate. It requires more energy to get the material from the magma reservoir to the surface,” said Bob Smith, a professor of geophysics in the Department of Geology at the University of Utah.
Smith is considered a leading expert on Yellowstone’s active supervolcano and its hazards, and he said 95% of Yellowstone’s danger is centered around earthquakes.
In part two of this series, Straight Arrow News will dig deeper into the earthquake danger, and why Yellowstone should be revered rather than feared.
“There are more geysers in Yellowstone than any place else on earth. About half the geysers in the world are in Yellowstone,” Poland said.