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SeismoAtlas

M1.0 earthquake 7 km NW of Rialto, California, United States

A magnitude 1.0 earthquake struck 7 km NW of Rialto, California, United States at 12:23 local time (19:23 UTC) on 20 Oct 2026, at a depth of 6 km, according to USGS.

revised from M1.4

Data: USGS · updated 2026-10-21 13:25 UTC · reviewed

Magnitude
1.0micro
local magnitude (Richter) (ml)
revised from 1.4
Depth
6.1 km
Status
Reviewed
Origin time
2026-10-20 19:23:17 UTC
Local: 20 Oct 2026, 12:23:17 (America/Los Angeles)
Epicentre
34.153° N, 117.425° 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
RialtoCalifornia, United States · pop. 103,1327 kmINot felt
FontanaCalifornia, United States · pop. 212,7047 kmINot felt
BloomingtonCalifornia, United States · pop. 23,8519 kmINot felt
San BernardinoCalifornia, United States · pop. 216,10813 kmINot felt
RiversideCalifornia, United States · pop. 317,26123 kmINot felt
AnaheimCalifornia, United States · pop. 350,74257 kmINot felt
Santa AnaCalifornia, United States · pop. 310,22761 kmINot felt
IrvineCalifornia, United States · pop. 256,92765 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 Survey1.0 mlwas 1.46.1 km34.15° N, 117.42° 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 477 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 6 km this was a shallow earthquake, which is felt more strongly at the surface than a deeper one of the same size.

The same size.

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

Aftershocks and nearby activity

126 later earthquakes within 30 km; the largest was M2.2 13 days ago. 14 in the 7 days before. Aftershock rates usually fall off roughly in proportion to 1/time.

Aftershocks

Mainshock M1.0

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

Aftershocks
Time after mainshock (hours)MagnitudeDepth (km)
7.170.77
21.951.015
32.731.37
35.870.94
36.331.04
36.741.34
38.200.95
38.470.95
39.131.213
56.680.53
57.561.84
57.590.96
58.451.05
58.451.55
59.260.715
61.021.34
62.212.07
62.241.67
62.251.37
63.220.87
89.980.99
97.711.13
99.240.71
99.760.89
103.260.78
108.720.811
113.120.611
116.891.48
128.091.012
131.780.612
137.901.67
140.281.06
145.341.02
147.790.97
149.160.813
149.161.011
151.170.77
155.461.012
174.241.213
189.021.14
189.261.26
190.061.34
190.120.85
191.721.15
192.271.15
192.301.85
192.431.14
195.030.85
195.341.07
195.351.34
195.562.05
196.041.33
198.900.614
198.970.94
199.181.14
199.800.84
201.320.83
217.830.94
222.682.24
222.820.94
223.051.37
223.872.26
223.881.37
223.891.04
223.910.94
224.300.94
224.301.23
225.591.36
225.591.87
226.320.65
226.590.73
226.690.68
227.650.54
227.990.96
227.991.06
228.000.74
228.980.84
229.221.24
229.370.93
229.580.75
229.600.75
229.630.54
230.030.96
230.041.65
230.091.06
231.190.85
232.920.74
232.931.14
237.241.010
240.750.97
243.871.04
246.380.94
246.591.14
253.501.09
257.150.76
257.461.25
257.490.95
262.282.16
266.691.111
270.241.04
271.490.65
279.640.316
280.570.75
294.171.19
347.430.713
347.480.714
356.541.24
371.930.716
391.380.914
391.380.413
395.820.617
396.871.04
397.231.113
403.660.97
410.411.316
417.661.513
419.631.017
420.451.016
421.981.16
422.010.915
452.251.011
465.490.87
491.711.113
504.261.08
537.211.110
546.981.69
  1. 2.2Near Loma Linda, California, United States10-30 02:04
  2. 2.2Near Loma Linda, California, United States10-30 03:15
  3. 2.1Near Loma Linda, California, United States10-31 17:40
  4. 2.04 km WNW of Fontana, California, United States10-23 09:35
  5. 2.0Near Loma Linda, California, United States10-28 22:56
  6. 1.8Near Loma Linda, California, United States10-28 19:41
  7. 1.8Near Loma Linda, California, United States10-30 04:58
  8. 1.85 km ESE of Loma Linda, California, United States10-23 04:57
  9. 1.64 km W of Fontana, California, United States10-26 13:17
  10. 1.6Near Loma Linda, California, United States10-30 09:25
  11. 1.64 km WNW of Fontana, California, United States10-23 09:37
  12. 1.64 km N of Jurupa Valley, California, United States11-12 14:22
  13. 1.5Near Loma Linda, California, United States11-07 05:02
  14. 1.55 km ESE of Loma Linda, California, United States10-23 05:50
  15. 1.46 km NW of Jurupa Valley, California, United States10-25 16:16
  16. 1.34 km SW of Redlands, California, United States10-28 23:25
  17. 1.35 km SW of Redlands, California, United States10-28 22:44
  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. 1.35 km SW of Redlands, California, United States10-23 08:24
  21. 1.36 km SSW of Redlands, California, United States11-06 21:47
  22. 1.3Near Loma Linda, California, United States10-30 03:16
  23. 1.3Near Loma Linda, California, United States10-30 04:58
  24. 1.34 km SW of Redlands, California, United States10-28 17:26
  25. 1.34 km WNW of Fontana, California, United States10-23 09:38

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 ci41349831. First recorded here 20 Oct 2026, 19:26:02 UTC. Solutions: USGS · CI (usgs:ci41349831). Cite as: SeismoAtlas, “M1.0 earthquake 7 km NW of Rialto, California, United States”, https://seismoatlas.com/earthquake/ci41349831-m1-0-earthquake-7-km-nw-of-rialto-california-united-states, data from USGS.

JSON: /api/v1/events/ci41349831. SeismoAtlas is not an official warning service.