Ronald C. Surdam
Wyoming State Geological Survey
P.O. Box 1347
Laramie, WY 82073
Editor in Chief
307-766-2286, ext. 255
|News Release||January 19, 2010|
Two minor earthquakes felt in Yellowstone
Two minor earthquakes were felt Jan. 18 in Yellowstone National Park. There were no reports of damage associated with either event.
The first earthquake, which occurred at 8:39 p.m., was felt in Yellowstone National Park and West Yellowstone, Mont., according to information received by the Wyoming State Geological Survey (WSGS).
The event occurred approximately 9 miles southeast of West Yellowstone and 18 miles eastnortheast of Island Park, Idaho.
The magnitude 3.3, intensity III earthquake occurred 6.2 miles below the surface, according to the U.S. Geological Survey’s National Earthquake Information Center (NEIC) in Golden, Colo.
The second earthquake, a magnitude 3.0 event, occurred at 9:42 p.m. and was felt in Yellowstone National Park at intensity II. The earthquake occurred 9 miles southeast of West Yellowstone and 18 miles east-northeast of Island Park at a depth of 6.3 miles.
Both earthquakes were associated with a small earthquake swarm that continued through 7 a.m. Jan. 19.
An earthquake swarm is a collection of small earthquakes that happen in the same general area and during the same time period. Earthquake swarms in Yellowstone National Park do not normally indicate that large, damaging earthquakes are imminent.
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 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 firstname.lastname@example.org .