Yellowstone National Park welcomed over 3 million visitors in 2022, according to the National Park Services. This popular destination is 2.2 million acres and hosts approximately half of the active geysers on the planet.
But what causes the stunning hydrothermal pools, the impressive geysers, and unique geologic environment of the first national park?
“Yellowstone is a really massive volcanic system,” said Michael Poland, scientist-in-charge at the Yellowstone Volcano Observatory (YVO) and a geophysicist at the United States Geological Survey (USGS).
This volcanic system is partially composed of a large magma field under the park.
“It’s about 30 miles across or so and 45 miles in another dimension,” said Poland. “So it’s big, but most of that magma chamber is solid. We’re able to do seismic imaging experiments […] and we can see that in places in the upper surface mostly you might have something like 25 to 30 percent melt, and the rest solid.”
With a 1,350 square mile magma field under northwestern Wyoming, many people jump to drastic conclusions and fear their safety. Could this super volcano erupt any day?
“Number one, [the large scale eruptions] are incredibly infrequent. And number two, thanks to the fact we have monitoring data and we’ve done research on Yellowstone, we know that that’s not really something that is likely to be occurring anytime soon,” said Poland.
Between the last major eruption of the Yellowstone volcanic system and the present day, the park has seen 40 to 50 lava flows, a much more common volcanic event. The last lava flow occurred 70,000 years ago, said Poland.
Far more common than lava flows or eruptions are large earthquakes which occur on a much more rapid timeline, with the most recent examples being the 7.3 magnitude earthquake that occurred in 1959, or the magnitude 6.0 quake in 1975.
While events like lava flows and eruptions are infrequent, it’s still important to monitor the geologic activity that takes place at the national park.
That’s where the Yellowstone Volcano Observatory (YVO) comes in. The consortium of institutions that monitor the activity of Yellowstone was formed in 2002 and consists of 9 different institutions.
“USGS, Yellowstone National Park, University of Utah- they do all the seismic monitoring in the region, a group called EarthScope- and they handle the GPS monitoring, the ground deformation, they handle that network, Montana State, University of Wyoming, and then the state geologic surveys of Wyoming, Montana, and Idaho. So we all work together to better understand Yellowstone.”
With consistent monitoring and the infrequency of large scale hazardous events that take place in Yellowstone, the fear of a sudden eruption is misplaced.
Poland summarized, “You’ve got to warm these things up, especially for a volcanic system like Yellowstone, that sort of magnitude. You got to warm it up. It’s like turning the oven on. It doesn’t go from zero to 400 in a second.”
