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M0.9 earthquake 9 km S of Los Serranos, California, United States

A magnitude 0.9 earthquake struck 9 km S of Los Serranos, California, United States at 09:16 local time (16:16 UTC) on 27 Oct 2026, at a depth of 8 km, according to USGS.

revised from M1.8

Data: USGS · updated 2026-10-28 15:35 UTC · reviewed

Magnitude
0.9micro
local magnitude (Richter) (ml)
revised from 1.8
Depth
8.4 km
Status
Reviewed
Origin time
2026-10-27 16:16:33 UTC
Local: 27 Oct 2026, 09:16:33 (America/Los Angeles)
Epicentre
33.892° N, 117.698° 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
Los SerranosCalifornia, United States · pop. 7,0999 kmINot felt
Yorba LindaCalifornia, United States · pop. 67,97310 kmINot felt
CoronaCalifornia, United States · pop. 164,22612 kmINot felt
Chino HillsCalifornia, United States · pop. 78,30912 kmINot felt
ChinoCalifornia, United States · pop. 85,59513 kmINot felt
AnaheimCalifornia, United States · pop. 350,74220 kmINot felt
Santa AnaCalifornia, United States · pop. 310,22722 kmINot felt
IrvineCalifornia, United States · pop. 256,92727 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 Survey0.9 mlwas 1.88.4 km33.89° N, 117.70° 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 294 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.

M1.0 releases about 1.6× the energy of M0.9, and its waves are about 1.4× taller on a seismogram. Energy: 477 g of TNT vs 294 g of TNT.

Each square is the energy of one M0.9. Energy from log₁₀E = 1.5M + 4.8.

Aftershocks and nearby activity

24 later earthquakes within 30 km; the largest was M1.8 8 days ago. 8 in the 7 days before. Aftershock rates usually fall off roughly in proportion to 1/time.

Aftershocks

Mainshock M0.9

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

Aftershocks
Time after mainshock (hours)MagnitudeDepth (km)
3.770.90
30.981.0-1
50.231.40
58.171.37
74.750.90
86.460.913
88.611.09
101.811.111
177.291.511
181.011.810
191.661.24
197.241.10
219.251.80
232.341.113
244.061.2-1
245.421.40
245.691.60
287.361.011
313.170.612
367.201.310
376.831.116
382.091.69
384.281.013
389.030.91
  1. 1.85 km ESE of Yorba Linda, California, United States11-04 05:16
  2. 1.8Near El Cerrito Corona, California, United States11-05 19:31
  3. 1.64 km ESE of El Cerrito Corona, California, United States11-06 21:57
  4. 1.64 km N of Jurupa Valley, California, United States11-12 14:22
  5. 1.5Near Placentia, California, United States11-04 01:33
  6. 1.4Near El Cerrito Corona, California, United States10-29 18:30
  7. 1.4Near Home Gardens, California, United States11-06 21:41
  8. 1.37 km NNW of Eastvale, California, United States10-30 02:26
  9. 1.33 km SW of Yorba Linda, California, United States11-11 23:28
  10. 1.2Near Home Gardens, California, United States11-06 20:20
  11. 1.26 km WNW of Jurupa Valley, California, United States11-04 15:55
  12. 1.1Near Rancho Cucamonga, California, United States10-31 22:04
  13. 1.1Near Yorba Linda, California, United States11-12 09:06
  14. 1.1Near El Cerrito Corona, California, United States11-04 21:30
  15. 1.14 km SSW of Rancho Cucamonga, California, United States11-06 08:36
  16. 1.0Near Home Gardens, California, United States10-28 23:15
  17. 1.05 km ENE of Rancho Cucamonga, California, United States11-08 15:38
  18. 1.04 km N of Jurupa Valley, California, United States10-31 08:53
  19. 1.0Near Charter Oak, California, United States11-12 16:33
  20. 0.9Near Home Gardens, California, United States11-12 21:18
  21. 0.94 km S of San Dimas, California, United States10-31 06:44
  22. 0.9Near Home Gardens, California, United States10-27 20:03
  23. 0.9Near Home Gardens, California, United States10-30 19:01
  24. 0.6Near Charter Oak, California, United States11-09 17:26

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 ci41353591. First recorded here 27 Oct 2026, 16:21:06 UTC. Solutions: USGS · CI (usgs:ci41353591). Cite as: SeismoAtlas, “M0.9 earthquake 9 km S of Los Serranos, California, United States”, https://seismoatlas.com/earthquake/ci41353591-m0-9-earthquake-9-km-s-of-los-serranos-california-united-states, data from USGS.

JSON: /api/v1/events/ci41353591. SeismoAtlas is not an official warning service.