QuakeIndex

Earthquake · reviewed by a seismologist

M 1.5ml

Earthquake near Loma Linda, CA

Yes. A magnitude 1.5 earthquake was recorded in Loma Linda, CA, at 10:24 pm PDT on 4 October 2026 (05:24 UTC), 17 km deep.

This was on 4 October 2026. The latest near Loma Linda: M 2.7 on 8 October 2026.

USGS: 1 km NW of Loma Linda, CA

5 km (3 mi) E of Colton, CA · 105 km (66 mi) E of Los Angeles, CA

10:24 pm PDT, Oct 4, 2026 · · 17 km deep · released about 5.6 lb of TNT

10 km30 km60 km120 km N Orange County 63 kmLos Angeles County 93 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
10:24 pm PDT on 4 October 2026 ()
Where
in Loma Linda, CA · earthquakes near Loma Linda
Magnitude
M 1.5 (ml)
Depth
17 km below the surface
Felt
no reports yet
Nearest
Orange County, 63 km SW
Nearest mapped fault
San Jacinto fault, under 1 km from its surface trace — near is not the same as on
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 8 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth it was probably too small to be felt, even directly above it. Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

Earthquakes near other towns within 30 km: Colton, Grand Terrace, San Bernardino, Highgrove, Redlands, Highland.

How big was it?

This earthquake released about 5.6 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,700,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,900,000× the energy of this one
  3. Around the size people start to feel M 3.0 170× the energy of this one
  4. This earthquake M 1.5 about 5.6 lb of TNT

Energy from the Gutenberg–Richter relation (log10E = 1.5M + 4.8), rounded to two figures; bar length is magnitude, which is already a logarithm of energy. Magnitudes of past earthquakes from the USGS catalogue.

For this area

The largest earthquake within 50 km since 2016 was M 4.5 on 2018-05-08 — about 30,000 times the energy of this one.

Before 2016, the USGS record lists 23 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.7 The 1918 San Jacinto, California Earthquake · 42 km SE of this epicentre
  2. 6.3 The 1992 Big Bear, California Earthquake · 44 km ENE of this epicentre
  3. 6.2 3 km SE of San Bernardino, California · 4 km NNE of this epicentre
  4. 6.0 The 1910 Lake Elsinore, California Earthquake · 41 km SSW of this epicentre
  5. 5.6 7km ENE of Running Springs, CA · 29 km NE of this epicentre

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Epicentre 34.0545, -117.2673. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Orange County, CA 63 km (39 mi) SW earthquakes near Orange County
Los Angeles County, CA 93 km (58 mi) W earthquakes near Los Angeles County
Riverside County, CA 122 km (76 mi) ESE earthquakes near Riverside County
San Diego County, CA 123 km (77 mi) SSE earthquakes near San Diego County
San Bernardino County, CA 134 km (83 mi) NE earthquakes near San Bernardino County

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

48 earthquakes have been recorded within 50 km since this one.

  1. 0.5 1 km WNW of Fontana, CA
  2. 1.8 2 km NE of Colton, CA
  3. 0.7 3 km W of Fontana, CA
  4. 1.1 2 km W of Fontana, CA
  5. 0.6 7 km N of Rancho Cucamonga, CA
  6. 1.0 3 km W of Fontana, CA
  7. 0.4 8 km NNW of Fontana, CA
  8. 1.2 2 km W of Fontana, CA
  9. 0.9 2 km WNW of Fontana, CA
  10. 0.8 2 km W of Fontana, CA
  11. 0.7 2 km W of Fontana, CA
  12. 1.2 3 km W of Fontana, CA
  13. 1.0 2 km W of Fontana, CA
  14. 1.1 2 km W of Fontana, CA
  15. 2.7 2 km WNW of Fontana, CA

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of . QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

Revisions

USGS refines a solution as more stations report. Every change we have seen is listed here.

What changedFromToWhen
review statusautomaticreviewed
longitude-117.27-117.27
latitude34.0534.05
depth17.3817.25
magnitude1.561.51
longitude-117.27-117.27
latitude34.0634.05
depth16.7317.38
magnitude1.611.56

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.