QuakeIndex

Fault · California

Polaris fault

30 kmlong (19 mi), as mapped
0.2–1 mm/yrhow fast it slips
< 15,000 yearssince it last broke the surface
30quakes 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.

The largest earthquake recorded near it was M 6.3 in 1857 (California-Nevada Border east of Truckee) — about 89,000 times the energy of an M3.0, the size people start to feel. It released about 43 kilotons 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: 0–0.

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

San Andreas faultGreat Valley thrust fault systemFoothills fault systemHoney Lake faultSmith Valley faultMohawk Valley faultCarson lineamentWarm Springs Valley faultTahoe-Sierra frontal faultWest Tahoe-Dollar Point faultAntelope Valley faultPyramid Lake faultUpper Long Valley faultEast Carson Valley faultMount Rose faultDog Valley faultNorth Tahoe faultGenoa faultSpanish Springs Valley faultIncline Village faultOlinghouse faultFort Sage faultLittle Valley faultCarson City faultKings Canyon faultPeavine Peak faultNorthern Virginia Range fault M 6.3 · 1857 · California-Nevada Border east of Truckee M 6.0 · 1855 · Sierra County, California M 6.0 · 1948 · 6 km WNW of Verdi, California
The Polaris fault as mapped at the surface (glowing), with the other mapped faults nearby, 30 of the M2.5+ earthquakes within 10 km of it since 2016 (dots), and the epicentres of the large historic earthquakes recorded near it (rings). 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 6.3 California-Nevada Border east of Truckee
    September 3, 1857 · epicentre 9 km from the trace
  2. M 6.0 Sierra County, California
    January 25, 1855 · epicentre 13 km from the trace
  3. M 6.0 6 km WNW of Verdi, California
    December 29, 1948 · epicentre 18 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 3.3 9 km NNE of Truckee, CA
    2026-05-22 · 4 km from the trace
  2. M 2.5 9 km NNE of Truckee, CA
    2026-05-22 · 4 km from the trace
  3. M 2.5 9 km NNE of Truckee, CA
    2026-05-22 · 4 km from the trace
  4. M 2.5 4 km E of Truckee, CA
    2024-11-26 · 1 km from the trace
  5. M 3.2 8 km NNE of Truckee, CA
    2024-02-10 · 2 km from the trace
  6. M 2.5 4 km N of Dollar Point, CA
    2023-09-18 · 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.