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M2.1 earthquake 5 km NNW of Fontana, California, United States

A magnitude 2.1 earthquake struck 5 km NNW of Fontana, California, United States at 17:41 local time (00:41 UTC) on 6 Oct 2026, at a depth of 9 km, according to USGS.

1 reports to USGS “Did You Feel It?”

Data: USGS · updated 2026-10-07 14:30 UTC · reviewed

Magnitude
2.1micro
local magnitude (Richter) (ml)
Depth
9.4 km
Status
Reviewed
Origin time
2026-10-07 00:41:20 UTC
Local: 6 Oct 2026, 17:41:20 (America/Los Angeles)
Epicentre
34.129° N, 117.457° 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
FontanaCalifornia, United States · pop. 212,7045 kmIIWeak
RialtoCalifornia, United States · pop. 103,1328 kmIIWeak
BloomingtonCalifornia, United States · pop. 23,8518 kmIIWeak
Rancho CucamongaCalifornia, United States · pop. 175,23612 kmINot felt
RiversideCalifornia, United States · pop. 317,26121 kmINot felt
AnaheimCalifornia, United States · pop. 350,74253 kmINot felt
Santa AnaCalifornia, United States · pop. 310,22757 kmINot felt
IrvineCalifornia, United States · pop. 256,92761 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 Survey2.1 mlwas 2.19.4 km34.13° N, 117.46° 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 24 kg 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 9 km this was a shallow earthquake, which is felt more strongly at the surface than a deeper one of the same size.

M2.1 releases about 35× the energy of M1.1, and its waves are about 11× taller on a seismogram. Energy: 24 kg of TNT vs 674 g of TNT.

Each square is the energy of one M1.1. Energy from log₁₀E = 1.5M + 4.8.

Aftershocks and nearby activity

174 later earthquakes within 30 km; the largest was M2.7 35 days ago. 26 in the 7 days before. Aftershock rates usually fall off roughly in proportion to 1/time.

Aftershocks

Mainshock M2.1

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

Aftershocks
Time after mainshock (hours)MagnitudeDepth (km)
6.030.817
7.720.616
9.211.216
9.490.73
11.960.69
19.071.416
24.960.96
25.721.57
25.941.16
29.220.96
31.080.916
31.170.97
31.461.47
31.462.76
31.731.16
33.341.07
33.561.27
33.890.77
33.980.87
33.980.97
34.131.27
35.120.47
35.171.05
35.730.67
37.811.16
38.710.76
39.131.816
39.770.55
39.820.97
39.980.87
52.741.217
55.690.75
57.670.87
58.541.78
69.131.75
72.170.911
77.621.014
78.230.85
85.440.914
89.151.516
98.731.014
102.551.115
122.421.13
132.220.918
134.080.914
143.381.54
143.620.415
175.141.715
183.821.04
193.850.615
201.871.03
239.201.56
249.270.75
266.101.04
270.980.912
271.500.712
282.971.615
286.900.916
293.922.416
302.711.317
302.771.317
330.701.06
330.921.1-1
337.870.77
352.641.015
363.431.37
366.570.94
367.031.04
367.441.34
368.900.95
369.170.95
369.831.213
387.380.53
388.261.84
388.290.96
389.151.05
389.151.55
389.960.715
391.721.34
392.912.07
392.941.67
392.951.37
393.920.87
420.680.99
428.411.13
429.940.71
430.460.89
433.960.78
439.420.811
443.820.611
447.591.48
458.791.012
462.480.612
468.601.67
470.981.06
476.041.02
478.490.97
479.860.813
479.861.011
481.870.77
486.161.012
499.360.90
504.941.213
519.721.14
519.961.26
520.761.34
520.820.85
522.421.15
522.961.15
523.001.85
523.131.14
525.730.85
526.041.07
526.051.34
526.262.05
526.561.0-1
526.741.33
529.600.614
529.670.94
529.881.14
530.490.84
532.020.83
548.530.94
553.382.24
553.520.94
553.751.37
554.572.26
554.581.37
554.591.04
554.610.94
555.000.94
555.001.23
556.291.36
556.291.87
557.020.65
557.290.73
557.390.68
558.350.54
558.680.96
558.691.06
558.690.74
559.680.84
559.921.24
560.060.93
560.280.75
560.290.75
560.330.54
560.730.96
560.741.65
560.791.06
561.880.85
563.620.74
563.621.14
567.941.010
570.340.90
571.450.97
574.571.04
577.080.94
577.291.14
584.201.09
587.850.76
588.161.25
588.180.95
592.982.16
597.391.111
600.941.04
602.190.65
610.340.316
611.270.75
624.871.19
678.130.713
678.170.714
687.241.24
702.630.716
  1. 2.74 km WNW of Fontana, California, United States10-08 08:09
  2. 2.4Near Loma Linda, California, United States10-19 06:36
  3. 2.2Near Loma Linda, California, United States10-30 02:04
  4. 2.2Near Loma Linda, California, United States10-30 03:15
  5. 2.1Near Loma Linda, California, United States10-31 17:40
  6. 2.04 km WNW of Fontana, California, United States10-23 09:35
  7. 2.0Near Loma Linda, California, United States10-28 22:56
  8. 1.8Near Loma Linda, California, United States10-28 19:41
  9. 1.8Near Loma Linda, California, United States10-30 04:58
  10. 1.8Near Colton, California, United States10-08 15:49
  11. 1.85 km ESE of Loma Linda, California, United States10-23 04:57
  12. 1.77 km WNW of Jurupa Valley, California, United States10-09 21:48
  13. 1.7Near Redlands, California, United States10-14 07:49
  14. 1.714 km NNE of Rancho Cucamonga, California, United States10-09 11:13
  15. 1.64 km W of Fontana, California, United States10-26 13:17
  16. 1.6Near Loma Linda, California, United States10-30 09:25
  17. 1.64 km WNW of Fontana, California, United States10-23 09:37
  18. 1.6Near Loma Linda, California, United States10-18 19:39
  19. 1.5Near Colton, California, United States10-10 17:50
  20. 1.514 km WNW of Muscoy, California, United States10-16 23:53
  21. 1.5Near Fontana, California, United States10-13 00:04
  22. 1.54 km WNW of Fontana, California, United States10-08 02:24
  23. 1.55 km ESE of Loma Linda, California, United States10-23 05:50
  24. 1.4Near Loma Linda, California, United States10-07 19:45
  25. 1.46 km NW of Jurupa Valley, California, United States10-25 16:16

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.

USGS “Did You Feel It?” has 1 reports: add yours at USGS.

Event id ci41344287. First recorded here 7 Oct 2026, 00:44:32 UTC. Solutions: USGS · CI (usgs:ci41344287). Cite as: SeismoAtlas, “M2.1 earthquake 5 km NNW of Fontana, California, United States”, https://seismoatlas.com/earthquake/ci41344287-m2-1-earthquake-5-km-nnw-of-fontana-california-united-states, data from USGS.

JSON: /api/v1/events/ci41344287. SeismoAtlas is not an official warning service.