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M0.9 earthquake 4 km S of San Dimas, California, United States

A magnitude 0.9 earthquake struck 4 km S of San Dimas, California, United States at 23:44 local time (06:44 UTC) on 30 Oct 2026, at a depth of 13 km, according to USGS.

Data: USGS · updated 2026-11-02 15:56 UTC · reviewed

Magnitude
0.9micro
local magnitude (Richter) (ml)
Depth
13.4 km
Status
Reviewed
Origin time
2026-10-31 06:44:14 UTC
Local: 30 Oct 2026, 23:44:14 (America/Los Angeles)
Epicentre
34.077° N, 117.805° W

Circles show this event and others within 30 km from 7 days before to 30 days after. Lines: plate boundaries and GEM active faults. Open on the live map

Nearby places

Distance and estimated shaking at nearby places
PlaceDistanceEst. shaking
San DimasCalifornia, United States · pop. 34,6304 kmINot felt
La VerneCalifornia, United States · pop. 32,6814 kmINot felt
Diamond BarCalifornia, United States · pop. 56,8975 kmINot felt
PomonaCalifornia, United States · pop. 153,2665 kmINot felt
AnaheimCalifornia, United States · pop. 350,74228 kmINot felt
Santa AnaCalifornia, United States · pop. 310,22737 kmINot felt
RiversideCalifornia, United States · pop. 317,26140 kmINot felt
Los AngelesCalifornia, United States · pop. 3,820,91440 kmINot felt

Shaking is an estimate from the intensity prediction equation of Allen, Wald & Worden (2012), not an observation. Local ground and buildings can change it by a level or more.

Every agency's solution

Agencies locate earthquakes with their own stations and methods, so their numbers differ. We match reports of the same event by time, distance and magnitude and show them side by side. The headline uses USGS · CI, which has been reviewed by an analyst.

AgencyMagnitudeDepthEpicentreTime offsetStatus
USGS · CIheadlineSouthern California Seismic Network via U.S. Geological Survey0.9 ml13.4 km34.08° N, 117.81° W–Reviewed · 1 revision

How big was it?

Usually not felt. Recorded by nearby seismometers; thousands occur worldwide every day.

It released roughly the energy of 349 g of TNT. Magnitude is logarithmic: each whole step means about 32 times more energy and 10 times larger waves on a seismogram. Depth matters too: at 13 km this was a shallow earthquake, which is felt more strongly at the surface than a deeper one of the same size.

M1.0 releases about 1.4× the energy of M0.9, and its waves are about 1.2× taller on a seismogram. Energy: 477 g of TNT vs 349 g of TNT.

Each square is the energy of one M0.9. Energy from log₁₀E = 1.5M + 4.8.

Aftershocks and nearby activity

19 later earthquakes within 30 km; the largest was M1.8 8 days ago. 10 in the 7 days before. Aftershock rates usually fall off roughly in proportion to 1/time.

Aftershocks

Mainshock M0.9

19 later earthquakes nearby. Aftershock rates typically fall off roughly as 1/time (Omori's law).

Aftershocks
Time after mainshock (hours)MagnitudeDepth (km)
2.151.09
15.341.111
40.361.212
90.831.511
94.551.810
105.191.24
109.711.1-1
140.030.413
140.291.314
145.881.113
146.740.512
191.830.811
200.901.011
226.700.612
280.741.310
290.371.116
295.631.69
297.821.013
302.651.44
  1. 1.85 km ESE of Yorba Linda, California, United States11-04 05:16
  2. 1.64 km N of Jurupa Valley, California, United States11-12 14:22
  3. 1.5Near Placentia, California, United States11-04 01:33
  4. 1.4Near Azusa, California, United States11-12 21:23
  5. 1.33 km SW of Yorba Linda, California, United States11-11 23:28
  6. 1.3Near La Mirada, California, United States11-06 03:01
  7. 1.26 km NNW of Glendora, California, United States11-01 23:06
  8. 1.26 km WNW of Jurupa Valley, California, United States11-04 15:55
  9. 1.1Near Rancho Cucamonga, California, United States10-31 22:04
  10. 1.1Near Yorba Linda, California, United States11-12 09:06
  11. 1.16 km NNW of Azusa, California, United States11-04 20:26
  12. 1.14 km SSW of Rancho Cucamonga, California, United States11-06 08:36
  13. 1.05 km ENE of Rancho Cucamonga, California, United States11-08 15:38
  14. 1.04 km N of Jurupa Valley, California, United States10-31 08:53
  15. 1.0Near Charter Oak, California, United States11-12 16:33
  16. 0.89 km NNW of Glendora, California, United States11-08 06:33
  17. 0.6Near Charter Oak, California, United States11-09 17:26
  18. 0.5Near El Monte, California, United States11-06 09:28
  19. 0.416 km N of Rancho Cucamonga, California, United States11-06 02:46

Did you feel it?

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Reports on SeismoAtlas

No reports yet.

Event id ci41570200. First recorded here 31 Oct 2026, 06:48:45 UTC. Solutions: USGS · CI (usgs:ci41570200). Cite as: SeismoAtlas, “M0.9 earthquake 4 km S of San Dimas, California, United States”, https://seismoatlas.com/earthquake/ci41570200-m0-9-earthquake-4-km-s-of-san-dimas-california-united-states, data from USGS.

JSON: /api/v1/events/ci41570200. SeismoAtlas is not an official warning service.