Mammoth, WY – A minor earthquake struck near the Montana–Idaho–Wyoming border early Sunday, shaking areas close to Yellowstone National Park.
According to the University of Utah Seismograph Stations, the 3.1 magnitude quake occurred at 7:38 a.m. UTC (1:38 a.m. local time) on Sunday, September 28, 2025. The epicenter was about 22 kilometers south-southwest of Mammoth, Wyoming, with a depth of 7.8 kilometers.
The tremor was located in the tri-state region where Montana, Idaho, and Wyoming meet, near the western edge of Yellowstone National Park. The U.S. Geological Survey’s “Did You Feel It?” map showed limited responses, with one report indicating light shaking. No injuries or damage have been reported at this time.
While small quakes are common in the Yellowstone region due to its geothermal and tectonic activity, they often raise public attention because of the area’s volcanic history. Officials stress that a 3.1 magnitude earthquake is considered minor and typically does not cause structural damage.
The University of Utah Seismograph Stations continues to monitor seismic activity in the Yellowstone region. Residents who felt the shaking are encouraged to share their experiences on the USGS website to help improve earthquake data collection.
