QuakeIndex

Fault · California

Extra fault

39 kmlong (24 mi), as mapped
not measuredhow fast it slips
< 15,000 yearssince it last broke the surface
159quakes 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 6.6 in 1942 (The 1942 Fish Creek Mountains, California Earthquake) — about 250,000 times the energy of an M3.0, the size people start to feel. It released about 120 kilotons of TNT.

This week vs. its last ten years

71/100

typical

1 quake of M1.5+ within 5 km of the trace in the last 7 days — busier than 71% of weeks since 2016. A normal week: 0–1.

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

San Andreas faultElsinore faultSan Jacinto faultBrawley Seismic ZoneImperial faultMecca Hills faultHidden Spring faultIndio Hills Fault ZoneCoachella Fan Fault ZoneYuha Well Fault ZoneSkeleton Canyon faultHot Springs faultYuha Basin faults M 6.6 · 1942 · The 1942 Fish Creek Mountains, California Earthquake M 6.6 · 1968 · The 1968 Borrego Mountain, California Earthquake M 6.5 · 1892 · Near Borrego Springs, California M 6.4 · 1954 · The 1954 San Jacinto Fault, California Earthquake
The Extra fault as mapped at the surface (glowing), with the other mapped faults nearby, 159 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 6.6 The 1942 Fish Creek Mountains, California Earthquake
    October 21, 1942 · epicentre 20 km from the trace
  2. M 6.6 The 1968 Borrego Mountain, California Earthquake
    April 9, 1968 · epicentre 14 km from the trace
  3. M 6.5 Near Borrego Springs, California
    May 28, 1892 · epicentre 22 km from the trace
  4. M 6.4 The 1954 San Jacinto Fault, California Earthquake
    March 19, 1954 · epicentre 22 km from the trace
  5. M 4.6 12km SSE of Bombay Beach, CA
    August 10, 2020 · epicentre 7 km from the trace
  6. M 4.5 17km SE of Ocotillo Wells, CA
    May 10, 2020 · epicentre 7 km from the trace
  7. M 4.3 6km SSE of Bombay Beach, CA
    September 27, 2016 · epicentre 3 km from the trace
  8. M 4.3 6km SSE of Bombay Beach, CA
    September 26, 2016 · epicentre 3 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 3.1 9 km SE of Ocotillo Wells, CA
    2026-07-15 · 4 km from the trace
  2. M 2.7 22 km ESE of Ocotillo Wells, CA
    2026-05-18 · 6 km from the trace
  3. M 2.6 22 km ESE of Ocotillo Wells, CA
    2026-05-18 · 7 km from the trace
  4. M 2.8 22 km ESE of Ocotillo Wells, CA
    2026-05-18 · 7 km from the trace
  5. M 3.1 22 km ESE of Ocotillo Wells, CA
    2026-05-18 · 7 km from the trace
  6. M 2.6 22 km ESE of Ocotillo Wells, CA
    2026-05-18 · 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.