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M 3.4 - 9 km SW of Brentwood, CA

Source: USGS · Northern California

A magnitude 3.4 earthquake was recorded by USGS near 9 km SW of Brentwood. On the USGS Earthquake Hazards Program scale, M3.4 is classified "Minor". Among the 1,708 earthquake reports Areazine has published, this M3.4 event ranks stronger than 26% of them (rank #1,171 by magnitude).

Read this earthquake report in 30 seconds

Magnitude
M 3.4
USGS class
Minor
Location
9 km SW of Brentwood
Archive rank
#1,171 of 1,708
Source
USGS
Published
September 12, 2026
MINOR

Stronger than 26% of the 1,708 earthquake reports in Areazine's archive, weaker than 1,170 others.

Record status: a point-in-time USGS detection. Aftershocks, revised magnitude, and felt-report data continue to update on USGS's own event page after publication.

What Happened

A magnitude 3.36 ml earthquake occurred at 03:25:55 UTC on September 12, 2026. The event was located 9 km SW of Brentwood, CA, at a depth of 17.89 km.

Location Details

The epicenter was at coordinates 37.8728°N, 121.8003°W. The depth of 17.89 km places this event in the shallow range (less than 20 km).

Impact Assessment

The earthquake was felt by 109 people, with a maximum reported intensity of 3.6 on the Community Decimal Intensity scale. No tsunami was generated (tsunami advisory status: 0). No alert level was issued.

What You Should Know

Earthquakes of this magnitude are often felt but rarely cause damage. Minor aftershocks remain possible in the area.

Source

Data from USGS: https://earthquake.usgs.gov/earthquakes/eventpage/nc75434122

Original source: USGS Official Notice ↗

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Elsewhere in the country: similar length or severity timing 8

Two Areazine-derived peer sets for this USGS earthquake report: nearest notices by body length and by same severity near the same agency date. Peers come from other categories so they are not the same-feed Related list above.

Similar body length

Nearest notices by article body length (780 characters here).

Bushfire Advice Alert for Cobark in Mid-Coast Region 780 chars Bushfire Advice Alert for South Kempsey Area 780 chars Grass Fire Advice Issued for Adams St in Narrandera 780 chars Planned Burn Alert in Queanbeyan-Palerang Area 780 chars

Similar severity timing

Same severity (low) notices issued closest in time to September 12, 2026.

Flood Alert for Humber Estuary from Spurn Point to Winestead Outfall (Sep 12, 2026) low Flood Alert for North Sea Coast at Withernsea, Easington and Kilnsea (Sep 12, 2026) low Yellow Frost Advisory for Edmundston and Madawaska County low Burn Off Alert: Douglas Park Dr, Douglas Park low

Frequently Asked Questions

Common questions about this USGS earthquake report.

What magnitude was this earthquake? ▾
A magnitude 3.36 earthquake struck 9 km southwest of Brentwood, California, on September 12, 2026.
What does a magnitude 3.4 ("Minor") earthquake mean? ▾
The USGS classifies M3.4 as "Minor" on its Earthquake Hazards Program scale. Events in this range are rarely felt beyond the immediate epicenter and typically cause no damage; most are recorded only by seismographs.
How does this compare with other earthquakes Areazine has reported? ▾
This is the #1,171 strongest of the 1,708 earthquake reports in Areazine's archive by magnitude, stronger than 26% of them and weaker than 1,170 others.
Was Brentwood likely to feel this earthquake? ▾
This event was centered 9 km SW of Brentwood. Shaking intensity falls off sharply with distance from the epicenter and depends on depth and local geology, so check the USGS "Did You Feel It?" report for this event for real felt-shaking data rather than assuming from magnitude and distance alone.

Where this data comes from

EPA Outdoor Air Quality Data

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AirNow (EPA / NOAA)

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National Weather Service

Active watches, warnings, and advisories, NOAA

CDC Air Quality & Health

Health-impact reference behind every AQI category