M0.8 earthquake 3 km NNW of Sierra Madre, California, United States
A magnitude 0.8 earthquake struck 3 km NNW of Sierra Madre, California, United States at 17:28 local time (00:28 UTC) on 22 Oct 2026, at a depth of 11 km, according to USGS.
revised from M1.7
Data: USGS · updated 2026-10-23 22:21 UTC · reviewed
- Magnitude
- 0.8micro
local magnitude (Richter) (ml)
revised from 1.7 - Depth
- 10.8 km
- Status
- Reviewed
- Origin time
- 2026-10-23 00:28:42 UTC
- Local: 22 Oct 2026, 17:28:42 (America/Los Angeles)
- Epicentre
- 34.184° N, 118.067° 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
| Place | Distance | Est. shaking |
|---|---|---|
| Sierra MadreCalifornia, United States · pop. 11,163 | 3 km | INot felt |
| East PasadenaCalifornia, United States · pop. 6,144 | 5 km | INot felt |
| ArcadiaCalifornia, United States · pop. 58,408 | 5 km | INot felt |
| AltadenaCalifornia, United States · pop. 42,777 | 6 km | INot felt |
| MonroviaCalifornia, United States · pop. 37,463 | 7 km | INot felt |
| PasadenaCalifornia, United States · pop. 142,250 | 8 km | INot felt |
| Los AngelesCalifornia, United States · pop. 3,820,914 | 22 km | INot felt |
| AnaheimCalifornia, United States · pop. 350,742 | 41 km | INot 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.
| Agency | Magnitude | Depth | Epicentre | Time offset | Status |
|---|---|---|---|---|---|
| USGS · CIheadlineSouthern California Seismic Network via U.S. Geological Survey | 0.8 mlwas 1.7 | 10.8 km | 34.18° N, 118.07° 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 284 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 11 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 1.7× the energy of M0.8, and its waves are about 1.4× taller on a seismogram. Energy: 477 g of TNT vs 284 g of TNT.
Each square is the energy of one M0.8. Energy from log₁₀E = 1.5M + 4.8.
Aftershocks and nearby activity
22 later earthquakes within 30 km; the largest was M1.7 15 days ago. 3 in the 7 days before. Aftershock rates usually fall off roughly in proportion to 1/time.
Mainshock M0.8
22 later earthquakes nearby. Aftershock rates typically fall off roughly as 1/time (Omori's law).
| Time after mainshock (hours) | Magnitude | Depth (km) |
|---|---|---|
| 92.80 | 1.0 | -1 |
| 123.09 | 1.1 | 11 |
| 123.88 | 1.7 | 11 |
| 126.60 | 0.9 | 11 |
| 130.27 | 0.7 | 9 |
| 130.83 | 0.8 | 11 |
| 133.20 | 0.7 | 10 |
| 133.88 | 0.7 | 11 |
| 133.99 | 0.8 | 10 |
| 135.01 | 1.3 | 11 |
| 177.88 | 1.1 | 11 |
| 198.26 | 0.9 | 13 |
| 203.45 | 0.5 | 7 |
| 238.62 | 1.2 | 12 |
| 307.97 | 1.1 | -1 |
| 338.54 | 1.3 | 14 |
| 345.00 | 0.5 | 12 |
| 369.26 | 1.1 | 16 |
| 390.09 | 0.8 | 11 |
| 424.96 | 0.6 | 12 |
| 496.08 | 1.0 | 13 |
| 500.91 | 1.4 | 4 |
- 1.73 km S of Glendale, California, United States10-28 04:21
- 1.4Near Azusa, California, United States11-12 21:23
- 1.36 km NE of Los Angeles, California, United States10-28 15:29
- 1.3Near La Mirada, California, United States11-06 03:01
- 1.26 km NNW of Glendora, California, United States11-01 23:06
- 1.14 km S of Glendale, California, United States10-28 03:34
- 1.16 km WSW of Burbank, California, United States11-07 09:44
- 1.1Near South El Monte, California, United States10-30 10:21
- 1.16 km NNW of Azusa, California, United States11-04 20:26
- 1.05 km NNW of Azusa, California, United States10-26 21:16
- 1.0Near Charter Oak, California, United States11-12 16:33
- 0.94 km S of San Dimas, California, United States10-31 06:44
- 0.94 km S of Glendale, California, United States10-28 07:04
- 0.89 km NNW of Glendora, California, United States11-08 06:33
- 0.83 km SSW of Glendale, California, United States10-28 11:18
- 0.83 km SSW of Glendale, California, United States10-28 14:28
- 0.73 km SSW of Glendale, California, United States10-28 13:40
- 0.74 km SSW of Glendale, California, United States10-28 14:21
- 0.77 km NE of La Crescenta-Montrose, California, United States10-28 10:44
- 0.6Near Charter Oak, California, United States11-09 17:26
- 0.5Near El Monte, California, United States11-06 09:28
- 0.56 km N of Altadena, California, United States10-31 11:55
Did you feel it?
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Reports on SeismoAtlas
No reports yet.
Event id ci41350831. First recorded here 23 Oct 2026, 00:33:09 UTC. Solutions: USGS · CI (usgs:ci41350831). Cite as: SeismoAtlas, “M0.8 earthquake 3 km NNW of Sierra Madre, California, United States”, https://seismoatlas.com/earthquake/ci41350831-m0-8-earthquake-3-km-nnw-of-sierra-madre-california-united-states, data from USGS.
JSON: /api/v1/events/ci41350831. SeismoAtlas is not an official warning service.