Breaking ground

By By Paige Fieldsted

By Paige Fieldsted

Six hundred thousand years ago, a volcanic eruption 1,000 times the size of the 1980 Mount St. Helens eruption created a giant volcanic crater now known as the Yellowstone Caldera.

And a 16-year U study shows that the active volcano is still shaping the landscape of the 45-by-30 mile caldera even though it hasn’t erupted in more than 50,000 years.

“Even though it is an active volcano, it isn’t spewing out lava,” said Robert Smith, U professor of geophysics. “But it is active in other ways.”

“Even when the volcano is not erupting, deformation is still going on,” said Christine Puskas, a graduate student in geophysics.

Observations taken from Global Positioning Systems have been monitoring movements in the ground for the past 16 years and have shown that the ground in the Yellowstone Caldera is moving at an average rate of 7 centimeters per year.

“That is a very high rate of movement, compared with the average half-millimeter per year the Wasatch Fault moves,” Smith said.

“Because of the hotspot, the ground is able to move (when there is) cracking,” Puskas said.

The U study, completed in 2004, shows that the 300-mile wide Yellowstone hotspot may be affecting more than just the caldera.

“The hotspot is also affecting movement in the Snake River Plain, and could explain the unexpected westward motion in the Teton Fault,” Puskas said.

Studies in the past have shown that the Teton Fault–located at the base of the Teton Range–and Jackson Hole are moving closer together rather than drifting apart, as was originally expected.

Even though the hotspot is causing deformation of the landscape in and around Yellowstone National Park, it is unlikely that there will be a catastrophic eruption or earthquake anytime soon.

“With the information we gather from the GPS systems, we can better predict when the volcano will erupt,” Puskas said.

“We monitor the volcano for public safety and provide data to the (National) Park Service for emergency planning,” Smith said. “(The volcano) is not a public safety problem right now, but it is still a good idea to take precautions.”