QuakeIndex

Earthquake · reviewed by a seismologist

M 2.2md

Earthquake near Brentwood, CA

No earthquake was likely felt in Brentwood in the 24 hours to 2:49 pm PST (22:49 UTC). The last one was M 3.0, 12 km (7 mi) WSW, at 6:47 am PDT on 14 September 2026, estimated intensity II (weak) in town; 52 felt reports to USGS. Every earthquake near Brentwood

This page: a magnitude 2.2 earthquake was recorded 9 km (6 mi) southwest of Brentwood, CA, at 7:38 pm PDT on 13 August 2023 (02:38 UTC), 17 km deep.

USGS: 7 km SW of Brentwood, CA

8 km (5 mi) SW of Brentwood, CA · 65 km (40 mi) N of San Jose, CA

7:38 pm PDT, Aug 13, 2023 · · 17 km deep · released about 64 lb of TNT

Every earthquake near Brentwood Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 16 kmAlameda County 28 kmSan Joaquin County 45 kmSolano County 45 kmSan Mateo County 73 kmSanta Clara County 73 kmSacramento County 74 kmStanislaus County 77 kmNapa County 85 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
7:38 pm PDT on 13 August 2023 ()
Where
9 km (6 mi) southwest of Brentwood, CA · earthquakes near Brentwood
Magnitude
M 2.2 (md)
Depth
17 km below the surface
Felt
no reports yet
Nearest
Contra Costa County, 16 km WNW
Nearest mapped fault
Greenville fault, 5 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 1175 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 8 km (5 mi) from the epicentre. In Brentwood, 9 km away, the estimate is intensity II (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.

Earthquakes near other towns within 30 km: Byron, Blackhawk, Knightsen, Antioch, Oakley, Clayton.

How big was it?

This earthquake released about 64 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.2 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 230,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 170,000× the energy of this one
  3. Around the size people start to feel M 3.0 15× the energy of this one
  4. This earthquake M 2.2 about 64 lb of TNT

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 2,300 times the energy of this one.

Before 2016, the USGS record lists 6 earthquakes of M5 or more within 50 km; the five largest:

  1. 5.8 The 1980 Livermore, California Earthquake · 4 km SSE of this epicentre
  2. 5.7 15 km NE of East Foothills, California · 45 km S of this epicentre
  3. 5.5 6 km NNE of East Foothills, California · 49 km S of this epicentre
  4. 5.4 South of Elmira, California · 48 km NNW of this epicentre
  5. 5.4 9 km NE of Livermore, 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 37.8783, -121.7798. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Contra Costa County, CA 16 km (10 mi) WNW earthquakes near Contra Costa County
Alameda County, CA 28 km (18 mi) SSW earthquakes near Alameda County
San Joaquin County, CA 45 km (28 mi) E earthquakes near San Joaquin County
Solano County, CA 45 km (28 mi) NNW earthquakes near Solano County
San Mateo County, CA 73 km (46 mi) SW earthquakes near San Mateo County
Santa Clara County, CA 73 km (46 mi) S earthquakes near Santa Clara County

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

Aftershocks so far

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

  1. 2.8 5 km SSW of Isleton, CA
  2. 4.2 5 km SW of Isleton, CA
  3. 1.9 24 km ENE of Alum Rock, CA
  4. 1.6 3 km SW of San Ramon, CA
  5. 2.4 8 km E of Fremont, CA
  6. 2.0 1 km E of Pacheco, CA
  7. 2.0 2 km N of San Ramon, CA
  8. 1.8 1 km SSE of Pacheco, CA
  9. 2.0 2 km ENE of Berkeley, CA
  10. 1.8 3 km W of Orinda, CA
  11. 2.2 1 km NE of San Leandro, CA
  12. 1.6 0 km WSW of Diablo, CA
  13. 2.2 9 km NE of Alum Rock, CA
  14. 2.5 3 km NNW of Piedmont, CA
  15. 2.0 9 km NE of Alum Rock, 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.