An earthquake is a release of energy within the Earth’s crust creating seismic waves that can cause significant damage. Earthquakes are triggered when unexpected movement along a fault occurs, volcanic activity increases, or along the boundaries of tectonic plates. Although ground shaking can occur by many processes, such as volcanic eruptions, the majority of earthquakes are related to movement along faults.
The largest earthquake recorded to date in Wyoming occurred on August 18th, 1959 in Yellowstone National Park. The earthquake registered as a magnitude 6.5 and is considered to be an aftershock of the magnitude 7.5 Hebgen Lake earthquake in southwestern Montana.
Rock Creek fault. Photo by Seth Wittke.
The WSGS maintains a database and catalogue of earthquake events in Wyoming. Below are website links for additional earthquake information.
- Geologic Hazards Interactive Map
- Earthquakes IMS Database
- Earthquakes in Wyoming-Information pamphlet
- USGS Earthquake Search 1973-current
- University of Utah Yellowstone EQ listings
- Earthquake Hazards Program Intermountain West Region
- USGS Latest Earthquakes
- Earthquakes in Wyoming
- Today in Earthquake History
- WSSPC (Western States Seismic Policy Council)
A fault is a shear fracture or a zone of fractures in the Earth’s crust that show evidence of displacement along blocks of crust. Sudden movement on a fault will release energy casing an earthquake.
Quaternary faults are recognized on the surface that have evidence of movement in the last 1.6 million years and are considered to have the greatest potential to be the sources of future earthquakes. Quaternary faults that show movement during the past 10,000 years are considered active. Approximately 80 Quaternary faults are mapped in Wyoming, with 26 considered active. To view a map of Quaternary Faults and Folds in Wyoming, click here.
USGS Quaternary Faults and Folds of Wyoming map and database