QuakeIndex

Fault · California

Quien Sabe fault

24 kmlong (15 mi), as mapped
0.2–1 mm/yrhow fast it slips
< 15,000 yearssince it last broke the surface
40quakes 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 6.5 in 1840 (Near San Juan Bautista, California) — about 180,000 times the energy of an M3.0, the size people start to feel. It released about 85 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 systemSan Gregorio faultCalaveras faultHayward faultGreenville faultMonterey Bay- Tularcitos faultZayante-Vergeles faultOrtigalita faultSargent faultMonte Vista-Shannon faultButano faultPfeiffer Point faultEast Monterey Bay faultTres Pinos fault M 6.5 · 1840 · Near San Juan Bautista, California M 6.4 · 1836 · Near San Juan Bautista, California M 6.3 · 1890 · East of Watsonville, California M 6.3 · 1897 · Near Gilroy, California M 6.0 · 1841 · Near San Juan Bautista, California M 6.0 · 1883 · Near Hollister, California
The Quien Sabe fault as mapped at the surface (glowing), with the other mapped faults nearby, 40 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 6.5 Near San Juan Bautista, California
    January 18, 1840 · epicentre 16 km from the trace
  2. M 6.4 Near San Juan Bautista, California
    June 10, 1836 · epicentre 15 km from the trace
  3. M 6.3 East of Watsonville, California
    April 24, 1890 · epicentre 24 km from the trace
  4. M 6.3 Near Gilroy, California
    June 20, 1897 · epicentre 20 km from the trace
  5. M 6.0 Near San Juan Bautista, California
    July 3, 1841 · epicentre 17 km from the trace
  6. M 6.0 Near Hollister, California
    March 30, 1883 · epicentre 18 km from the trace
  7. M 4.4 1km NNW of Tres Pinos, CA
    April 4, 2023 · epicentre 4 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 2.6 2 km NW of Hollister, CA
    2026-09-23 · 8 km from the trace
  2. M 3.6 2 km ENE of Ridgemark, CA
    2026-05-17 · 5 km from the trace
  3. M 3.0 3 km SSE of Ridgemark, CA
    2025-04-04 · 7 km from the trace
  4. M 3.0 8 km S of Tres Pinos, CA
    2024-12-08 · 9 km from the trace
  5. M 2.5 14 km NE of Hollister, CA
    2024-10-24 · 7 km from the trace
  6. M 2.5 14 km ENE of Hollister, CA
    2024-10-02 · 7 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.