QuakeIndex

Fault · Idaho, Wyoming

Grand Valley fault

136 kmlong (85 mi), as mapped
0.2–1 mm/yrhow fast it slips
< 15,000 yearssince it last broke the surface
14quakes of M2.5+ within 10 km since 2016

In plain English

The two sides move 0.2 to 1 mm a year — 2 to 10 cm every century.

Its most recent surface rupture is younger than 15,000 years.

USGS maps it as 4 sections: Grand Valley section, Prater Mountain section, Star Valley section, Swan Valley section.

This week vs. its last ten years

93/100

elevated

1 quake of M1.5+ within 5 km of the trace in the last 7 days — busier than 93% of weeks since 2016. A normal week: 0–0.

Computed from the USGS catalogue · a description of the past, not a forecast · method

Wasatch faultEast Cache faultEastern Bear Lake faultTeton faultWest Cache faultWestern Bear Lake faultGreys River faultRock Creek faultBuffalo Fork faultHeise faultEast Mount Sheridan faults
The Grand Valley fault as mapped at the surface (glowing), with the other mapped faults nearby, 14 of the M2.5+ earthquakes within 10 km of it since 2016 (dots), . Traces: USGS Quaternary Fault and Fold Database. Historic epicentres are estimates.

Every year since 2016

Earthquakes of M2.5+ with an epicentre within 10 km of the mapped trace. Near is not the same as on: some will have slipped on neighbouring faults.

Most recent near it

  1. M 2.6 5 km NNE of Star Valley Ranch, Wyoming
    2025-10-23 · 3 km from the trace
  2. M 2.5 17 km E of Irwin, Idaho
    2025-09-20 · 6 km from the trace
  3. M 2.8 5 km NE of Star Valley Ranch, Wyoming
    2025-07-12 · 4 km from the trace
  4. M 2.7 6 km E of Etna, Wyoming
    2024-08-29 · 3 km from the trace
  5. M 3.1 10 km W of Hoback, Wyoming
    2024-08-09 · 10 km from the trace
  6. M 3.1 10 km WSW of Hoback, Wyoming
    2024-08-02 · 9 km from the trace

Neighbouring faults

Fault trace, slip rate and age: USGS Quaternary Fault and Fold Database (public domain), simplified for the web. Earthquakes: USGS ComCat. QuakeIndex does not forecast earthquakes; a fault's history describes the past. For early warning use ShakeAlert.