QuakeIndex

Earthquake · reviewed by a seismologist

M 3.3mw

Earthquake near Clayton, CA

No earthquake was likely felt in Clayton in the 24 hours to 11:42 pm PST (07:42 UTC). The last one was M 2.1, 11 km (7 mi) W, at 4:05 am PST on 8 November 2026, estimated intensity II (weak) in town; 3 felt reports to USGS. Every earthquake near Clayton

This page: a magnitude 3.3 earthquake was recorded 8 km (5 mi) east of Clayton, CA, at 3:00 pm PDT on 15 September 2025 (22:00 UTC), 7.5 km deep. 642 people have reported feeling it to USGS.

USGS: 8 km E of Clayton, CA

6 km (4 mi) SW of Antioch, CA

3:00 pm PDT, Sep 15, 2025 · · 7.5 km deep · released about 1.2 tons of TNT

Every earthquake near Clayton Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 9 kmAlameda County 33 kmSolano County 37 kmSan Joaquin County 51 kmSacramento County 72 kmSan Mateo County 74 kmNapa County 75 kmMarin County 79 kmSanta Clara County 81 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
3:00 pm PDT on 15 September 2025 ()
Where
8 km (5 mi) east of Clayton, CA · earthquakes near Clayton
Magnitude
M 3.3 (mw)
Depth
7.5 km below the surface
Felt
642 reports · strongest reported intensity III
Measured shaking
intensity III (ShakeMap)
Nearest
Contra Costa County, 9 km WSW
Nearest mapped fault
Greenville fault, 4 km from its surface trace — near is not the same as on
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 344 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 50 km (31 mi) from the epicentre. In Clayton, 8 km away, the estimate is intensity III (weak). Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

Likely felt in: Antioch 8 km, intensity III · Pittsburg 10 km, intensity III · Brentwood 14 km, intensity III · Oakley 14 km, intensity III · Concord 16 km, intensity III · Pleasant Hill 18 km, intensity III · Danville 19 km, intensity III · Alamo 19 km, intensity III. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 1.2 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.3 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 140,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 6,200× the energy of this one
  3. Magna, Utah 2020 M 5.7 4,400× the energy of this one
  4. This earthquake M 3.3 about 1.2 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 2.5× more

Energy from the Gutenberg–Richter relation (log10E = 1.5M + 4.8), rounded to two figures; bar length is magnitude, which is already a logarithm of energy. Magnitudes of past earthquakes from the USGS catalogue.

For this area

The largest earthquake within 50 km since 2016 was M 4.5 on 2019-10-15 — about 61 times the energy of this one.

Before 2016, the USGS record lists 4 earthquakes of M5 or more within 50 km:

  1. 5.8 The 1980 Livermore, California Earthquake · 13 km SSE of this epicentre
  2. 5.4 South of Elmira, California · 40 km N of this epicentre
  3. 5.4 9 km NE of Livermore, California · 25 km SSE of this epicentre
  4. 5.1 11 km E of Blackhawk, California · 16 km SSE of this epicentre

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Epicentre 37.9412, -121.8502. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Contra Costa County, CA 9 km (6 mi) WSW earthquakes near Contra Costa County
Alameda County, CA 33 km (21 mi) S earthquakes near Alameda County
Solano County, CA 37 km (23 mi) NNW earthquakes near Solano County
San Joaquin County, CA 51 km (31 mi) E earthquakes near San Joaquin County
Sacramento County, CA 72 km (45 mi) NE earthquakes near Sacramento County
San Mateo County, CA 74 km (46 mi) SW earthquakes near San Mateo County

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

59 earthquakes have been recorded within 50 km since this one.

  1. 2.3 3 km SE of San Ramon, CA
  2. 3.0 4 km SE of San Ramon, CA
  3. 2.9 4 km SE of San Ramon, CA
  4. 2.3 4 km SE of San Ramon, CA
  5. 3.0 4 km SE of San Ramon, CA
  6. 3.8 3 km SE of San Ramon, CA
  7. 1.7 6 km ENE of Vallejo, CA
  8. 1.6 5 km SE of Oakland, CA
  9. 1.7 4 km E of Brentwood, CA
  10. 2.4 5 km SE of Oakland, CA
  11. 2.6 2 km WNW of Concord, CA
  12. 1.6 8 km NNW of Lafayette, CA
  13. 2.0 8 km E of Suisun City, CA
  14. 2.0 2 km ENE of San Ramon, CA
  15. 1.6 7 km NNW of Lafayette, CA

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of . QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.