QuakeIndex

Fault · California

Cleghorn fault

25 kmlong (16 mi), as mapped
1–5 mm/yrhow fast it slips
< 130,000 yearssince it last broke the surface
16quakes of M2.5+ within 10 km since 2016

In plain English

The two sides move 1 to 5 mm a year — 10 to 50 cm (4 to 20 inches) every century.

Its most recent surface rupture is younger than 130,000 years.

The largest earthquake recorded near it was M 7.5 in 1812 (Northwest of San Bernardino, California) — about 5,600,000 times the energy of an M3.0, the size people start to feel. It released about 2.7 megatons of TNT.

USGS maps it as 2 sections: Northern Cleghorn section, Southern Cleghorn section.

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 faultElsinore faultGarlock faultSan Jacinto faultNewport-Inglewood-Rose Canyon faultLenwood-Lockhart faultHelendale-South Lockhart faultSan Gabriel faultSierra Madre faultCalico-Hidalgo faultCatalina faultPalos Verdes faultCamp Rock-Emerson-Copper Mountain faultPinto Mountain fault (includes Morongo Valley fault)San Pedro Basin faultNorth Frontal thrust systemHarper faultJohnson Valley faultPuente Hills blind thrust systemSan Gorgonio Pass faultManix faultHomestead Valley faultSan Joaquin Hills thrustRaymond faultCrafton Hills faultMt. General faultBanning faultLong Canyon faultHollywood faultOld Woman Springs faultRed Hill-Etiwanda Avenue faultBeaumont Plain fault M 7.5 · 1812 · Northwest of San Bernardino, California M 6.4 · 1899 · Cajon Pass area, northwest of San Bernardino, California M 6.2 · 1923 · 3 km SE of San Bernardino, California M 6.2 · 1894 · Northwest of San Bernardino, California M 6.0 · 1858 · Near San Bernardino, California
The Cleghorn fault as mapped at the surface (glowing), with the other mapped faults nearby, 16 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 7.5 Northwest of San Bernardino, California
    December 8, 1812 · epicentre 19 km from the trace
  2. M 6.4 Cajon Pass area, northwest of San Bernardino, California
    July 22, 1899 · epicentre 4 km from the trace
  3. M 6.2 3 km SE of San Bernardino, California
    July 23, 1923 · epicentre 20 km from the trace
  4. M 6.2 Northwest of San Bernardino, California
    July 30, 1894 · epicentre 13 km from the trace
  5. M 6.0 Near San Bernardino, California
    December 16, 1858 · epicentre 10 km from the trace
  6. M 4.2 1 km W of Lytle Creek, CA
    January 5, 2024 · epicentre 7 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 2.5 4 km SE of Lytle Creek, CA
    2026-01-18 · 7 km from the trace
  2. M 3.7 6 km N of Lytle Creek, CA
    2025-08-06 · 3 km from the trace
  3. M 2.6 4 km NNW of Lytle Creek, CA
    2025-05-24 · 6 km from the trace
  4. M 2.9 2 km SSE of Devore, CA
    2024-06-20 · 9 km from the trace
  5. M 4.2 1 km W of Lytle Creek, CA
    2024-01-05 · 7 km from the trace
  6. M 2.5 3 km E of Devore, CA
    2023-10-26 · 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.