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M1.2 earthquake 5 km NNE of Rancho Cucamonga, California, United States

A magnitude 1.2 earthquake struck 5 km NNE of Rancho Cucamonga, California, United States at 08:19 local time (15:19 UTC) on 1 Oct 2026, at a depth of 8 km, according to USGS.

Data: USGS · updated 2026-10-01 17:28 UTC · reviewed

Magnitude
1.2micro
local magnitude (Richter) (ml)
Depth
8.5 km
Status
Reviewed
Origin time
2026-10-01 15:19:04 UTC
Local: 1 Oct 2026, 08:19:04 (America/Los Angeles)
Epicentre
34.157° N, 117.575° 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
Rancho CucamongaCalifornia, United States · pop. 175,2365 kmINot felt
UplandCalifornia, United States · pop. 76,4439 kmINot felt
OntarioCalifornia, United States · pop. 171,21413 kmINot felt
MontclairCalifornia, United States · pop. 38,69014 kmINot felt
RiversideCalifornia, United States · pop. 317,26128 kmINot felt
AnaheimCalifornia, United States · pop. 350,74247 kmINot felt
Santa AnaCalifornia, United States · pop. 310,22753 kmINot felt
IrvineCalifornia, United States · pop. 256,92759 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 Survey1.2 mlwas 1.28.5 km34.16° N, 117.57° W–Reviewed · 2 revisions

How big was it?

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

It released roughly the energy of 829 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 8 km this was a shallow earthquake, which is felt more strongly at the surface than a deeper one of the same size.

M1.2 releases about 1.7× the energy of M1.0, and its waves are about 1.4× taller on a seismogram. Energy: 829 g of TNT vs 477 g of TNT.

Each square is the energy of one M1.0. Energy from log₁₀E = 1.5M + 4.8.

Aftershocks and nearby activity

72 later earthquakes within 30 km; the largest was M2.7 35 days ago. 9 in the 7 days before. Aftershock rates usually fall off roughly in proportion to 1/time.

Aftershocks

Mainshock M1.2

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

Aftershocks
Time after mainshock (hours)MagnitudeDepth (km)
43.670.710
52.551.95
52.551.75
56.680.87
59.980.77
66.370.93
126.861.011
129.372.19
138.581.216
141.330.69
154.330.96
155.091.57
155.311.16
158.600.96
160.540.97
160.831.47
160.832.76
161.101.16
162.711.07
162.931.27
163.270.77
163.350.87
163.350.97
163.501.27
164.490.47
164.541.05
165.100.67
167.181.16
168.080.76
168.501.816
169.150.55
169.190.97
169.350.87
185.060.75
187.050.87
187.911.78
198.501.75
218.521.516
251.791.13
272.751.54
313.191.04
331.241.03
368.571.56
395.471.04
460.071.06
467.240.77
492.801.37
514.291.710
516.750.53
522.282.07
522.311.67
522.321.37
523.290.87
545.360.95
557.791.13
559.310.71
559.830.89
563.330.78
576.961.48
588.161.012
597.971.67
600.351.06
605.411.02
607.860.97
611.240.77
634.311.213
683.121.37
697.311.010
706.450.94
706.661.14
711.420.913
713.571.09
  1. 2.74 km WNW of Fontana, California, United States10-08 08:09
  2. 2.15 km NNW of Fontana, California, United States10-07 00:41
  3. 2.04 km WNW of Fontana, California, United States10-23 09:35
  4. 1.97 km NNW of Eastvale, California, United States10-03 19:52
  5. 1.8Near Colton, California, United States10-08 15:49
  6. 1.76 km WNW of Jurupa Valley, California, United States10-03 19:52
  7. 1.77 km WNW of Jurupa Valley, California, United States10-09 21:48
  8. 1.75 km SSW of Piñon Hills, California, United States10-23 01:36
  9. 1.714 km NNE of Rancho Cucamonga, California, United States10-09 11:13
  10. 1.64 km W of Fontana, California, United States10-26 13:17
  11. 1.64 km WNW of Fontana, California, United States10-23 09:37
  12. 1.5Near Colton, California, United States10-10 17:50
  13. 1.514 km WNW of Muscoy, California, United States10-16 23:53
  14. 1.5Near Fontana, California, United States10-13 00:04
  15. 1.54 km WNW of Fontana, California, United States10-08 02:24
  16. 1.46 km NW of Jurupa Valley, California, United States10-25 16:16
  17. 1.45 km W of Fontana, California, United States10-08 08:08
  18. 1.37 km NNW of Eastvale, California, United States10-30 02:26
  19. 1.314 km WNW of Muscoy, California, United States10-22 04:07
  20. 1.34 km WNW of Fontana, California, United States10-23 09:38
  21. 1.24 km W of Fontana, California, United States10-08 10:15
  22. 1.2Near Colton, California, United States10-07 09:54
  23. 1.27 km NW of Muscoy, California, United States10-28 01:37
  24. 1.24 km WNW of Fontana, California, United States10-08 10:49
  25. 1.1Near Fontana, California, United States10-12 03:06

Did you feel it?

Reports from people help show where shaking was strong. They are anonymous and shown here in aggregate.

Reports close 14 days after an earthquake.

Reports on SeismoAtlas

No reports yet.

Event id ci41341671. First recorded here 1 Oct 2026, 15:21:52 UTC. Solutions: USGS · CI (usgs:ci41341671). Cite as: SeismoAtlas, “M1.2 earthquake 5 km NNE of Rancho Cucamonga, California, United States”, https://seismoatlas.com/earthquake/ci41341671-m1-2-earthquake-5-km-nne-of-rancho-cucamonga-california-united-states, data from USGS.

JSON: /api/v1/events/ci41341671. SeismoAtlas is not an official warning service.