Wyoming State Geological Survey
Ronald C. Surdam
Director/State Geologist
Wyoming State Geological Survey
P.O. Box 1347
Laramie, WY 82073



Contact Information

Robert Waggener
Editor in Chief
307-766-2286, ext. 255

News Release January 5, 2010

Minor earthquake felt in western Wyoming

A minor earthquake Dec. 31 near the Idaho-Wyoming border was felt by residents in northern Lincoln County. There were no reports of injuries or damage.

The earthquake, which occurred at 5:13 p.m., was felt in Afton, Auburn, Freedom and Grover, according to information received by the Wyoming State Geological Survey (WSGS). The event occurred approximately 10 miles southwest of Afton and 8 miles southwest of Smoot.

The magnitude 3.0, intensity IV earthquake occurred 3.1 miles below the surface, according to the U.S. Geological Survey’s National Earthquake Information Center (NEIC) in Golden, Colo.

The strength of an earthquake at its epicenter is called its magnitude, as measured on the Richter scale. Minor earthquakes – those between magnitude 3.0 and 3.9 – do not cause structural damage.

The effect of an earthquake on the surface is called its intensity, as measured on the Modified Mercalli Intensity Scale. Intensities range from I (imperceptible shaking) to XII (catastrophic destruction).

The NEIC’s Did You Feel It? program reported that the earthquake was felt as intensity IV in Grover, intensity III in Afton and Auburn and intensity II in Freedom. An intensity IV earthquake is felt indoors by many and outdoors by some, and it can damage dishes, windows and doors.

The WSGS has compiled seismological characterizations of all Wyoming counties, which include analyses of historic seismicity. See Earthquake Database for more information, or contact Seth Wittke at 307-766-2286, ext. 244, or by e-mail at seth.wittke@wyo.gov .