QuakeIndex

Fault · California

Calaveras fault

156 kmlong (97 mi), as mapped
> 5 mm/yrhow fast it slips
last 150 yearssince it last broke the surface
782quakes of M2.5+ within 10 km since 2016

In plain English

The two sides grind past each other faster than 5 mm a year — more than half a metre (20 inches) every century.

It has broken the ground surface within the last 150 years.

The largest earthquake recorded near it was M 6.8 in 1868 (The 1868 Hayward Fault, California Earthquake) — about 500,000 times the energy of an M3.0, the size people start to feel. It released about 240 kilotons of TNT.

USGS maps it as 4 sections: Central Calaveras fault section, Northern Calaveras section, Paicines section, Southern Calaveras section.

This week vs. its last ten years

50/100

typical

5 quakes of M1.5+ within 5 km of the trace in the last 7 days — busier than 50% of weeks since 2016. A normal week: 3–7.

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

San Andreas faultGreat Valley thrust fault systemSan Gregorio faultFoothills fault systemHayward faultGreenville faultMonterey Bay- Tularcitos faultZayante-Vergeles faultOrtigalita faultRodgers Creek faultSargent faultMonte Vista-Shannon faultButano faultWest Napa faultBennett Valley faultGreen Valley faultPfeiffer Point faultEast Monterey Bay faultQuien Sabe faultConcord faultPleasanton faultCordelia faultSerra faultTres Pinos faultCorral Hollow-Carnegie faultLas Positas fault M 6.8 · 1868 · The 1868 Hayward Fault, California Earthquake M 6.5 · 1840 · Near San Juan Bautista, California M 6.5 · 1865 · South of San Jose, California M 6.5 · 1911 · Near Morgan Hill, California M 6.4 · 1836 · Near San Juan Bautista, California M 6.3 · 1890 · East of Watsonville, California
The Calaveras 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), 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 6.8 The 1868 Hayward Fault, California Earthquake
    October 21, 1868 · epicentre 14 km from the trace
  2. M 6.5 Near San Juan Bautista, California
    January 18, 1840 · epicentre 8 km from the trace
  3. M 6.5 South of San Jose, California
    October 8, 1865 · epicentre 21 km from the trace
  4. M 6.5 Near Morgan Hill, California
    July 1, 1911 · epicentre 6 km from the trace
  5. M 6.4 Near San Juan Bautista, California
    June 10, 1836 · epicentre 6 km from the trace
  6. M 6.3 East of Watsonville, California
    April 24, 1890 · epicentre 14 km from the trace
  7. M 5.1 15km ESE of Alum Rock, CA
    October 25, 2022 · epicentre on the trace
  8. M 4.7 17km SSE of Tres Pinos, CA
    October 15, 2019 · 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 · 0 km from the trace
  2. M 2.5 10 km ENE of Milpitas, CA
    2026-09-19 · 2 km from the trace
  3. M 2.6 21 km E of Alum Rock, CA
    2026-09-17 · 8 km from the trace
  4. M 2.7 5 km NW of Pinnacles, CA
    2026-08-11 · 8 km from the trace
  5. M 2.6 6 km NW of Pinnacles, CA
    2026-08-11 · 8 km from the trace
  6. M 3.9 6 km NW of Pinnacles, CA
    2026-08-11 · 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.