QuakeIndex

Fault · California

Northridge blind thrust

33 kmlong (21 mi), as mapped
not measuredhow fast it slips
last 150 yearssince it last broke the surface
29quakes of M2.5+ within 10 km since 2016

In plain English

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

The largest earthquake recorded near it was M 6.6 in 1971 (1971 San Fernando Earthquake, California) — about 250,000 times the energy of an M3.0, the size people start to feel. It released about 120 kilotons of TNT.

A blind thrust does not reach the surface; the line on the map is the USGS's projection of it, not a crack you can stand on.

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 faultElsinore faultGarlock faultNewport-Inglewood-Rose Canyon faultSanta Ynez faultLenwood-Lockhart faultHelendale-South Lockhart faultSan Gabriel faultSierra Madre faultPitas Point faultCatalina faultPalos Verdes faultOak Ridge fault (offshore)Mission Ridge fault systemSan Pedro Basin faultSanta Cruz Island faultMalibu Coast faultSanta Cruz faultDume faultOak Ridge faultSimi-Santa Rosa faultPuente Hills blind thrust systemSan Cayetano faultRed Mountain faultPleito faultSanta Monica faultWheeler Ridge faultSan Joaquin Hills thrustRaymond faultVerdugo faultHollywood faultVentura fault M 6.6 · 1971 · 1971 San Fernando Earthquake, California
The Northridge blind thrust as mapped at the surface (glowing), with the other mapped faults nearby, 29 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 1971 San Fernando Earthquake, California
    February 9, 1971 · epicentre 11 km from the trace
  2. M 4.2 1km SE of Sylmar, CA
    July 30, 2020 · 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 2.6 9 km SW of Valencia, CA
    2026-08-12 · 2 km from the trace
  2. M 2.8 10 km SSW of Valencia, CA
    2026-02-08 · 2 km from the trace
  3. M 2.5 10 km SSW of Valencia, CA
    2025-12-27 · 2 km from the trace
  4. M 2.6 10 km SSW of Valencia, CA
    2025-12-27 · 2 km from the trace
  5. M 2.5 10 km SSW of Valencia, CA
    2025-12-25 · 2 km from the trace
  6. M 2.6 6 km W of Castaic, CA
    2025-10-06 · 8 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.