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M1.5 quarry blast near El Cerrito Corona, California, United States

A magnitude 1.5 quarry blast struck near El Cerrito Corona, California, United States at 15:21 local time (22:21 UTC) on 1 Oct 2026, at a depth of -1 km, according to USGS.

revised from M1.6

Data: USGS · updated 2026-10-02 17:46 UTC · reviewed

Magnitude
1.5micro
local magnitude (Richter) (ml)
revised from 1.6
Depth
-0.5 km
Status
Reviewed
Origin time
2026-10-01 22:21:19 UTC
Local: 1 Oct 2026, 15:21:19 (America/Los Angeles)
Epicentre
33.837° N, 117.496° 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
El Cerrito CoronaCalifornia, United States · pop. 5,1002 kmIIIWeak
Home GardensCalifornia, United States · pop. 11,5705 kmIIWeak
CoronaCalifornia, United States · pop. 164,2268 kmINot felt
NorcoCalifornia, United States · pop. 26,28911 kmINot felt
EastvaleCalifornia, United States · pop. 59,03915 kmINot felt
RiversideCalifornia, United States · pop. 317,26115 kmINot felt
IrvineCalifornia, United States · pop. 256,92735 kmINot felt
Santa AnaCalifornia, United States · pop. 310,22736 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. Likely felt out to about 3 km.

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 Survey1.5 mlwas 1.8-0.5 km33.84° N, 117.50° 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 3 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 -1 km this was a shallow earthquake, which is felt more strongly at the surface than a deeper one of the same size.

M1.5 releases about 5.2× the energy of M1.0, and its waves are about 3× taller on a seismogram. Energy: 3 kg 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

62 later earthquakes within 30 km; the largest was M2.7 35 days ago. 11 in the 7 days before. Aftershock rates usually fall off roughly in proportion to 1/time.

Aftershocks

Mainshock M1.5

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

Aftershocks
Time after mainshock (hours)MagnitudeDepth (km)
20.661.00
45.511.75
45.511.95
45.801.07
82.730.99
117.400.36
145.290.30
147.300.96
148.051.57
148.271.16
151.560.96
153.500.97
153.791.47
153.802.76
154.061.16
155.681.07
155.901.27
156.230.77
156.310.87
156.310.97
156.461.27
157.511.05
160.151.16
161.040.76
162.110.55
162.150.97
162.310.87
178.030.75
180.010.87
191.461.75
191.501.50
244.751.13
265.711.54
306.151.04
309.821.70
357.571.22
358.371.04
393.320.912
393.840.712
416.150.210
453.251.1-1
476.891.12
501.781.10
515.242.07
515.271.67
515.281.37
516.250.87
524.241.3-1
561.750.811
566.160.611
569.921.48
590.931.67
593.311.06
598.701.4-1
617.920.98
621.700.90
648.901.0-1
668.151.40
676.091.37
692.670.90
705.900.613
706.531.09
  1. 2.74 km WNW of Fontana, California, United States10-08 08:09
  2. 2.04 km WNW of Fontana, California, United States10-23 09:35
  3. 1.97 km NNW of Eastvale, California, United States10-03 19:52
  4. 1.76 km WNW of Jurupa Valley, California, United States10-03 19:52
  5. 1.77 km WNW of Jurupa Valley, California, United States10-09 21:48
  6. 1.7Near El Cerrito Corona, California, United States10-14 20:10
  7. 1.64 km W of Fontana, California, United States10-26 13:17
  8. 1.64 km WNW of Fontana, California, United States10-23 09:37
  9. 1.5Near Fontana, California, United States10-13 00:04
  10. 1.54 km WNW of Fontana, California, United States10-08 02:24
  11. 1.54 km ESE of El Cerrito Corona, California, United States10-09 21:51
  12. 1.4Near El Cerrito Corona, California, United States10-29 18:30
  13. 1.43 km ENE of El Cerrito Corona, California, United States10-26 21:03
  14. 1.46 km NW of Jurupa Valley, California, United States10-25 16:16
  15. 1.45 km W of Fontana, California, United States10-08 08:08
  16. 1.37 km NNW of Eastvale, California, United States10-30 02:26
  17. 1.3Near El Cerrito Corona, California, United States10-23 18:35
  18. 1.34 km WNW of Fontana, California, United States10-23 09:38
  19. 1.2Near El Cerrito Corona, California, United States10-16 19:55
  20. 1.24 km W of Fontana, California, United States10-08 10:15
  21. 1.24 km WNW of Fontana, California, United States10-08 10:49
  22. 1.1Near Fontana, California, United States10-12 03:06
  23. 1.1Near Home Gardens, California, United States10-20 19:36
  24. 1.14 km N of Lake Elsinore, California, United States10-22 20:08
  25. 1.14 km WNW of Fontana, California, United States10-08 02:37

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 ci41341855. First recorded here 1 Oct 2026, 22:24:08 UTC. Solutions: USGS · CI (usgs:ci41341855). Cite as: SeismoAtlas, “M1.5 quarry blast near El Cerrito Corona, California, United States”, https://seismoatlas.com/earthquake/ci41341855-m1-5-quarry-blast-near-el-cerrito-corona-california-united-states, data from USGS.

JSON: /api/v1/events/ci41341855. SeismoAtlas is not an official warning service.