JACKSON, Wyo. - After lifting the Grand Teton mountains more than 6,000 feet over the past 13 million years, geological forces have reversed that motion and have raised the Jackson Hole valley 1.7 inches in 17 years, scientists said in a study.

Geophysicists using global positioning system technology gathered data showing that the valley floor of Jackson Hole is actually moving upward in relation to the Teton Range, the opposite of what scientists would normally expect along a geological feature like the Teton Fault.

Jackson Hole has also moved west one-quarter inch during the same time period. The finding is part of a larger $2.3 million study by University of Utah researchers on the Yellowstone hot spot.

The scientists placed GPS devices at over 140 sites in the Yellowstone area between 1987 and 2003, using satellites to measure small movements in the Earth's crust.

"We began to see this several years ago and we weren't sure if it was really happening," said Jackson Hole resident and geophysicist Robert Smith, one of the study's authors. "Normally, the valley goes down and the mountains go up and that's how you got the Tetons."

According to Smith, the Teton Fault's proximity to the Yellowstone plateau might have something to do with this sudden, in geologic time, change in direction.

The 50-mile-wide, 410-mile-deep plume of molten rock that is pushing up on the Earth's crust in Yellowstone is causing the National Park to rise like a pimple, Smith said. The Teton Fault is a close neighbor to the hot spot, which would be essentially "pushing Jackson Hole into the Teton Range."

"When you deform one region you're causing stress on the surrounding regions," Smith said. "When you have high topography, the earth wants to slide downhill. The Earth wants to get down to equilibrium."

The pressure from the Yellowstone hot spot could explain why the magnitude 7 to 7.5 earthquakes that formed the Teton Range have ceased in the past 4,800 years.

Smith said the scenario explaining Jackson Hole's rise is just an educated guess at this point.

- Information from: Jackson Hole News And Guide, http://www.jhnewsandguide.com