QuakeIndex

Fault · Idaho

Beaverhead fault

121 kmlong (75 mi), as mapped
< 0.2 mm/yrhow fast it slips
< 15,000 yearssince it last broke the surface
3quakes of M2.5+ within 10 km since 2016

In plain English

The two sides move less than 0.2 mm a year — under 2 cm a century. Slow faults can still produce large earthquakes, just rarely.

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

USGS maps it as 6 sections: Baldy Mountain section, Blue Dome section, Leadore section, Lemhi section, Mollie Gulch section, Nicholia section.

This week vs. its last ten years

Too quiet to rank: fewer than half a year's worth of weeks with any M1.5+ quake within 5 km, in ten years. A single quake here would read as "unusual", so we do not score it.

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

Lemhi faultLost River faultRed Rock faultLone Pine fault
The Beaverhead fault as mapped at the surface (glowing), with the other mapped faults nearby, 3 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 3.2 18 km N of Leadore, Idaho
    2026-05-25 · 9 km from the trace
  2. M 2.5 28 km SSE of Leadore, Idaho
    2023-11-25 · 6 km from the trace
  3. M 3.1 36 km SW of Lima, Montana
    2016-01-31 · 8 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.