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M0.8 earthquake 10 km ESE of East Foothills, California, United States

A magnitude 0.8 earthquake struck 10 km ESE of East Foothills, California, United States at 09:47 local time (16:47 UTC) on 27 Sept 2026, at a depth of 8 km, according to USGS.

Data: USGS · updated 2026-09-28 20:06 UTC · reviewed

Magnitude
0.8micro
duration magnitude (md)
Depth
7.6 km
Status
Reviewed
Origin time
2026-09-27 16:47:05 UTC
Local: 27 Sept 2026, 09:47:05 (America/Los Angeles)
Epicentre
37.352° N, 121.712° 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
East FoothillsCalifornia, United States · pop. 8,26910 kmINot felt
San JoseCalifornia, United States · pop. 997,36816 kmINot felt
MilpitasCalifornia, United States · pop. 77,60420 kmINot felt
Santa ClaraCalifornia, United States · pop. 126,21522 kmINot felt
CampbellCalifornia, United States · pop. 41,11722 kmINot felt
OaklandCalifornia, United States · pop. 419,26770 kmINot felt
StocktonCalifornia, United States · pop. 305,65877 kmINot felt
San FranciscoCalifornia, United States · pop. 827,52678 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 · NC, which has been reviewed by an analyst.

AgencyMagnitudeDepthEpicentreTime offsetStatus
USGS · NCheadlineNorthern California Seismic System via U.S. Geological Survey0.8 md7.6 km37.35° N, 121.71° W–Reviewed

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How big was it?

Usually not felt. Recorded by nearby seismometers; thousands occur worldwide every day.

It released roughly the energy of 256 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 1.9× the energy of M0.8, and its waves are about 1.5× taller on a seismogram. Energy: 477 g of TNT vs 256 g of TNT.

Each square is the energy of one M0.8. Energy from log₁₀E = 1.5M + 4.8.

Aftershocks and nearby activity

4 later earthquakes within 30 km; the largest was M2.1 17 h ago. 13 in the 7 days before. Aftershock rates usually fall off roughly in proportion to 1/time.

Aftershocks

Mainshock M0.8

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

Aftershocks
Time after mainshock (hours)MagnitudeDepth (km)
1.271.34
4.371.25
12.032.16
12.041.44
  1. 2.110 km NNE of East Foothills, California, United States09-28 04:49
  2. 1.429 km W of Patterson, California, United States09-28 04:49
  3. 1.329 km W of Patterson, California, United States09-27 18:03
  4. 1.229 km WSW of Patterson, California, United States09-27 21:09

Did you feel it?

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Reports on SeismoAtlas

No reports yet.

Event id nc75443177. First recorded here 28 Sept 2026, 20:32:13 UTC. Solutions: USGS · NC (usgs:nc75443177). Cite as: SeismoAtlas, “M0.8 earthquake 10 km ESE of East Foothills, California, United States”, https://seismoatlas.com/earthquake/nc75443177-m0-8-earthquake-10-km-ese-of-east-foothills-california-united-states, data from USGS.

JSON: /api/v1/events/nc75443177. SeismoAtlas is not an official warning service.