QuakeIndex

Fault · Idaho

Sawtooth fault

60 kmlong (37 mi), as mapped
< 0.2 mm/yrhow fast it slips
< 15,000 yearssince it last broke the surface
946quakes 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.

The largest earthquake recorded near it was M 4.8 in 2020 (21 km WNW of Stanley, Idaho) — about 500 times the energy of an M3.0, the size people start to feel. It released about 240 tons of TNT.

This week vs. its last ten years

0/100

quiet

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

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

Lost River faultLone Pine fault
The Sawtooth fault as mapped at the surface (glowing), with the other mapped faults nearby, 400 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.

The big ones recorded near it

  1. M 4.8 21 km WNW of Stanley, Idaho
    April 1, 2020 · epicentre 2 km from the trace
  2. M 4.4 23 km NW of Stanley, Idaho
    April 1, 2020 · epicentre 4 km from the trace
  3. M 4.4 26 km NW of Stanley, Idaho
    May 21, 2020 · epicentre 10 km from the trace
  4. M 4.2 13 km WSW of Stanley, Idaho
    August 8, 2020 · epicentre 6 km from the trace
  5. M 4.2 10 km NW of Stanley, Idaho
    June 14, 2020 · epicentre 5 km from the trace
  6. M 4.2 11 km NW of Stanley, Idaho
    June 9, 2020 · epicentre 8 km from the trace

Before 1973 from the USGS ComCat historical catalogue (within 25 km; epicentres of old earthquakes are estimates). Since 2016, M4+ within 10 km.

Most recent near it

  1. M 3.2 23 km NW of Stanley, Idaho
    2026-09-12 · 5 km from the trace
  2. M 3.3 23 km NW of Stanley, Idaho
    2026-09-06 · 4 km from the trace
  3. M 2.8 23 km WNW of Stanley, Idaho
    2026-08-12 · 6 km from the trace
  4. M 2.5 22 km NW of Stanley, Idaho
    2026-06-20 · 3 km from the trace
  5. M 2.8 21 km NW of Stanley, Idaho
    2026-04-09 · 4 km from the trace
  6. M 2.7 14 km WNW of Stanley, Idaho
    2026-03-20 · 4 km from the trace

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.