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M1.0 earthquake 10 km N of Rancho Cucamonga, California, United States

A magnitude 1.0 earthquake struck 10 km N of Rancho Cucamonga, California, United States at 19:47 local time (02:47 UTC) on 17 Oct 2026, at a depth of 4 km, according to USGS.

Data: USGS · updated 2026-10-18 14:00 UTC · reviewed

Magnitude
1.0micro
local magnitude (Richter) (ml)
Depth
3.9 km
Status
Reviewed
Origin time
2026-10-18 02:47:13 UTC
Local: 17 Oct 2026, 19:47:13 (America/Los Angeles)
Epicentre
34.196° N, 117.582° 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. 175,23610 kmINot felt
UplandCalifornia, United States · pop. 76,44312 kmINot felt
MontclairCalifornia, United States · pop. 38,69016 kmINot felt
OntarioCalifornia, United States · pop. 171,21416 kmINot felt
RiversideCalifornia, United States · pop. 317,26132 kmINot felt
AnaheimCalifornia, United States · pop. 350,74250 kmINot felt
Santa AnaCalifornia, United States · pop. 310,22756 kmINot felt
IrvineCalifornia, United States · pop. 256,92762 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 ml3.9 km34.20° N, 117.58° 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 430 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 4 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 1.1× the energy of M1.0, and its waves are about 1.1× taller on a seismogram. Energy: 477 g of TNT vs 430 g of TNT.

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

Aftershocks and nearby activity

47 later earthquakes within 30 km; the largest was M2.0 20 days ago. 4 in the 7 days before. Aftershock rates usually fall off roughly in proportion to 1/time.

Aftershocks

Mainshock M1.0

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

Aftershocks
Time after mainshock (hours)MagnitudeDepth (km)
64.601.06
71.770.77
97.331.37
118.821.710
121.280.53
126.812.07
126.841.67
126.851.37
127.820.87
149.890.95
162.321.13
163.840.71
164.360.89
167.860.78
181.491.48
192.691.012
202.501.67
204.881.06
209.941.02
212.390.97
215.770.77
238.841.213
287.651.37
301.851.010
310.980.94
311.191.14
315.950.913
318.101.09
331.291.111
356.311.212
358.771.19
421.141.24
446.090.96
455.980.914
455.980.413
461.831.113
468.260.97
486.610.915
507.780.811
516.851.011
530.090.87
542.660.612
556.311.113
568.871.08
601.811.110
611.581.69
613.771.013
  1. 2.04 km WNW of Fontana, California, United States10-23 09:35
  2. 1.75 km SSW of Piñon Hills, California, United States10-23 01:36
  3. 1.64 km W of Fontana, California, United States10-26 13:17
  4. 1.64 km WNW of Fontana, California, United States10-23 09:37
  5. 1.64 km N of Jurupa Valley, California, United States11-12 14:22
  6. 1.46 km NW of Jurupa Valley, California, United States10-25 16:16
  7. 1.37 km NNW of Eastvale, California, United States10-30 02:26
  8. 1.314 km WNW of Muscoy, California, United States10-22 04:07
  9. 1.34 km WNW of Fontana, California, United States10-23 09:38
  10. 1.26 km NNW of Glendora, California, United States11-01 23:06
  11. 1.26 km WNW of Jurupa Valley, California, United States11-04 15:55
  12. 1.27 km NW of Muscoy, California, United States10-28 01:37
  13. 1.111 km NW of Muscoy, California, United States11-10 07:05
  14. 1.1Near Rancho Cucamonga, California, United States10-31 22:04
  15. 1.110 km N of Rancho Cucamonga, California, United States10-31 01:58
  16. 1.17 km ENE of Muscoy, California, United States10-24 21:06
  17. 1.113 km NE of Rancho Cucamonga, California, United States11-02 01:33
  18. 1.114 km WNW of Muscoy, California, United States11-12 04:35
  19. 1.14 km SSW of Rancho Cucamonga, California, United States11-06 08:36
  20. 1.07 km ENE of Muscoy, California, United States10-26 20:43
  21. 1.04 km NW of Muscoy, California, United States10-30 16:37
  22. 1.05 km ENE of Rancho Cucamonga, California, United States11-08 15:38
  23. 1.04 km N of Jurupa Valley, California, United States10-31 08:53
  24. 1.07 km NW of Rialto, California, United States10-20 19:23
  25. 1.0Near Charter Oak, California, United States11-12 16:33

Did you feel it?

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

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Reports on SeismoAtlas

No reports yet.

Event id ci41348727. First recorded here 18 Oct 2026, 02:51:18 UTC. Solutions: USGS · CI (usgs:ci41348727). Cite as: SeismoAtlas, “M1.0 earthquake 10 km N of Rancho Cucamonga, California, United States”, https://seismoatlas.com/earthquake/ci41348727-m1-0-earthquake-10-km-n-of-rancho-cucamonga-california-united-states, data from USGS.

JSON: /api/v1/events/ci41348727. SeismoAtlas is not an official warning service.