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 April 15, 2010

Utah earthquake felt April 15 in southwestern Wyoming

A light earthquake occurred April 15 in eastern Utah and was felt in much of southwestern Wyoming. There were no immediate reports of injuries or damage associated with the event.

The earthquake, which occurred at 5:59 p.m., was felt in Uinta, Sweetwater and Lincoln counties, according to information received by the Wyoming State Geological Survey (WSGS).

The event was approximately 31 miles north-northwest of Evanston and 27 miles south-southwest of Cokeville.

The magnitude 4.9, intensity VI earthquake was 4.9 miles below the surface, according to the U.S. Geological Survey’s National Earthquake Information Center (NEIC) in Golden, Colo.

It was reportedly felt as intensity II in Rock Springs and Evanston and intensity IV in Cokeville. During an intensity IV event, hanging objects swing, vehicles that are not moving rock, vibrations are felt similar to that of a passing truck, windows and dishes rattle and glasses clink.

The strength of an earthquake at its epicenter is called its magnitude, as measured on the Richter scale. Light earthquakes – those between magnitude 4.0 and 4.9 – can but do not usually 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 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.