Earthquake Hits Wyoming; Landslide Reported

October 26, 2010

A magnitude 4.6 earthquake hit northwest Wyoming just before noon Sunday, Oct. 24, apparently triggering a landslide on a quarter-mile stretch of a hiking trail, but no injuries have been reported.

Some hikers may have been further up the trail — beyond the landslide — but authorities don’t know how many, Bridger-Teton National Forest spokeswoman Mary Cernicek said.

No one is believed to have been in the slide, which wouldn’t prevent any hikers from getting out, she said.

University of Utah geophysics professor Bob Smith was at his Jackson home when the quake hit at about 11:45 a.m.

“It really was more of a very slow rolling motion. It only lasted a few seconds,” said Smith, who has studied the seismology of the region for 40 years.

Smith said an east-west fault in the area has caused persistent earthquakes since the 1920s, and the nature of the soil makes it prone to landslides.

He said the fault, along the Gros Ventre mountain range, isn’t visible on the surface. He said it’s distinct from a north-south fault along the Teton Range.

No damage was reported in Jackson or in Grand Teton National Park, west of where the slide was reported.

Heather Voster, a dispatcher at park headquarters in Moose, about 12 miles north of Jackson, said she felt “just a mild shaking” that lasted less than 10 minutes.