Wallace L. Ulrich

Acting Director & State Geologist
Wyoming State Geological Survey
P.O. Box 1347
Laramie, WY 82073


MEDIA ADVISORY
Wyoming State Geological Survey

Earthquake activity continues in Teton County
August 9, 2010

A minor earthquake occurred Aug. 7 at 5:19 a.m. in east-central Teton County. There was no immediate report of injury or damage.

The magnitude 3.3 tremor was in the same area as other recent earthquakes near the Red Hills along the Gros Ventre River, according to information received by the Wyoming State Geological Survey (WSGS). Six earthquakes ranging from magnitude 2.5 to magnitude 4.8 took place in the four-day period beginning Aug. 4.

The recent activity is similar to a sequence of tremors that occurred in early 2004 in the same area, said Harley Benz, scientist-in-charge at the U.S. Geological Survey National Earthquake Information Center in Golden, Colo., and Seth Wittke, a geologist with the WSGS. The 2004 events died away after a number of months.

“Although the recent events most likely do not point toward a large-magnitude earthquake, a small probability does exist that they may be precursors to a larger event,” Benz said.

The epicenter of the Aug. 7 earthquake was approximately 20 miles east-northeast of Jackson and 40 miles west of Dubois at a depth of 3.1 miles.

The event was felt as intensity III in Moose and intensity II in Wilson. During an intensity III event, ground motion is noticed by people indoors, standing motor cars may rock slightly and vibrations similar to a truck passing by can be felt.

The WSGS, in collaboration with the USGS, continues to monitor the seismicity of the area in real time through a temporary strong-motion accelerometer. The instrument, which measures ground acceleration, was placed in the area late last week to record these seismic events as they happen.

“A second accelerometer is being installed to gather more data. Data collected will provide scientists continued understanding of the local seismicity,” said WSGS Acting Director and State Geologist Wallace Ulrich.

Individuals who experience ground motion or damage from this or any earthquake are encouraged to participate in the USGS “Did You Feel It” program by visiting http://earthquake.usgs.gov/earthquakes/dyfi/ to fill out a short questionnaire.

Additionally, those with information or questions about earthquakes in Wyoming can contact Wittke at seth.wittke@wyo.gov or 307-766 2286, ext. 244, or Ulrich at wallace.ulrich@wyo.gov or 307-766-2286, ext. 223.