Yellowstone's effects far-reaching

BILLINGS, Mont. (AP) — Scientists studying a giant volcanic hotspot beneath Yellowstone National Park said Thursday that even when the hotspot is inactive, it exerts energy that shapes the landscape 150 miles away.

The findings from the University of Utah challenge long-standing beliefs that earthquakes triggered by volcanic activity account for most of the landscape changes related to Yellowstone's hotspot, a volcanic plume more than 300 miles wide located deep beneath the earth's surface.

Instead, much of the deformations were traced to more-constant pressures coming from the plume, said Robert Smith, a professor of geophysics and one of the authors of the new study.

Smith said the results, which came out of a broader $2.3 million study of Yellowstone's geophysics, could help in forecasting future earthquakes or volcanic eruptions.

Using satellite data to measure movements of the earth's crust over the past 17 years, Smith and his colleagues found the earth's surface was stretching by up to 4 millimeters a year due to energy released by the hotspot. They also found that a giant crater located above the hotspot — the Yellowstone caldera — rises and falls without always triggering eruptions.

"The energy that goes into deforming the ground is much greater than the earthquakes," said Christine Puskas, the lead author of the study. "Regional deformation even is being experienced as far as the Snake River Valley in Idaho."

The study was published Friday in the Journal of Geophysical Research - Solid Earth.