QuakeIndex

Fault · California

Konocti Bay fault

22 kmlong (14 mi), as mapped
not measuredhow fast it slips
< 15,000 yearssince it last broke the surface
184quakes of M2.5+ within 10 km since 2016

In plain English

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

The largest earthquake recorded near it was M 4.7 in 2025 (4 km NW of Cobb, CA) — about 300 times the energy of an M3.0, the size people start to feel. It released about 140 tons of TNT.

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

San Andreas faultGreat Valley thrust fault systemBartlett Springs fault systemMaacama faultHunting Creek-Berryessa fault systemRodgers Creek faultWest Napa faultBennett Valley faultGreen Valley faultAlexander-Redwood Hill faultBig Valley fault
The Konocti Bay fault as mapped at the surface (glowing), with the other mapped faults nearby, 184 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 4.7 4 km NW of Cobb, CA
    January 2, 2025 · epicentre 6 km from the trace
  2. M 4.4 7km WNW of Cobb, CA
    April 12, 2023 · epicentre 9 km from the trace
  3. M 4.3 9 km WNW of Cobb, CA
    December 5, 2024 · epicentre 10 km from the trace
  4. M 4.2 2km WNW of Cobb, CA
    June 28, 2022 · epicentre 7 km from the trace
  5. M 4.2 3 km SSW of Cobb, California
    February 21, 2017 · epicentre 10 km from the trace
  6. M 4.2 5 km W of Cobb, CA
    February 21, 2026 · epicentre 9 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 2.8 4 km W of Cobb, CA
    2026-09-12 · 9 km from the trace
  2. M 3.0 10 km WNW of Cobb, CA
    2026-09-10 · 9 km from the trace
  3. M 2.8 10 km WNW of Cobb, CA
    2026-09-10 · 10 km from the trace
  4. M 2.8 7 km NW of The Geysers, CA
    2026-08-11 · 10 km from the trace
  5. M 3.0 7 km NW of The Geysers, CA
    2026-08-11 · 10 km from the trace
  6. M 2.6 3 km ENE of The Geysers, CA
    2026-07-27 · 10 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.