QuakeIndex

Earthquake · reviewed by a seismologist

M 1.5md

Earthquake near Brentwood, CA

No earthquake was likely felt in Brentwood in the 24 hours to 2:44 am PST (10:44 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 1.5 earthquake was recorded 6 km (4 mi) west-southwest of Brentwood, CA, at 7:17 am PDT on 6 July 2020 (14:17 UTC), 2.7 km deep.

USGS: 4km WSW of Brentwood, CA

in Brentwood, CA · 68 km (43 mi) N of San Jose, CA

7:17 am PDT, Jul 6, 2020 · · 2.7 km deep · released about 5.9 lb of TNT

10 km30 km60 km120 km N Contra Costa County 17 kmAlameda County 32 kmSolano County 43 kmSan Joaquin County 43 kmSacramento County 70 kmSanta Clara County 77 kmSan Mateo County 77 kmStanislaus County 77 kmNapa County 83 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
7:17 am PDT on 6 July 2020 ()
Where
6 km (4 mi) west-southwest of Brentwood, CA · earthquakes near Brentwood
Magnitude
M 1.5 (md)
Depth
2.7 km below the surface
Felt
no reports yet
Nearest
Contra Costa County, 17 km W
Nearest mapped fault
Greenville fault, 9 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 2321 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 10 km (6 mi) from the epicentre. In Brentwood, 6 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.

Likely felt in: Brentwood 6 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 5.9 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,500,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,800,000× the energy of this one
  3. Around the size people start to feel M 3.0 160× the energy of this one
  4. This earthquake M 1.5 about 5.9 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 25,000 times the energy of this one.

Before 2016, the USGS record lists 5 earthquakes of M5 or more within 50 km:

  1. 5.8 The 1980 Livermore, California Earthquake · 8 km S of this epicentre
  2. 5.7 15 km NE of East Foothills, California · 48 km S of this epicentre
  3. 5.4 South of Elmira, California · 45 km NNW of this epicentre
  4. 5.4 9 km NE of Livermore, California · 19 km SSE of this epicentre
  5. 5.1 11 km E of Blackhawk, California · 11 km S 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 37.9098, -121.7630. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Contra Costa County, CA 17 km (10 mi) W earthquakes near Contra Costa County
Alameda County, CA 32 km (20 mi) SSW earthquakes near Alameda County
Solano County, CA 43 km (26 mi) NNW earthquakes near Solano County
San Joaquin County, CA 43 km (27 mi) E earthquakes near San Joaquin County
Sacramento County, CA 70 km (44 mi) NNE earthquakes near Sacramento County
Santa Clara County, CA 77 km (48 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

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

  1. 2.6 10km NNE of Milpitas, CA
  2. 2.0 7km S of Livermore, CA
  3. 1.9 7km S of Livermore, CA
  4. 3.3 10km NE of Milpitas, CA
  5. 2.9 10km NE of Milpitas, CA
  6. 2.7 10km NE of Milpitas, CA
  7. 2.1 4km ESE of Berkeley, CA
  8. 1.7 1km SW of Diablo, CA
  9. 1.9 10km NE of Milpitas, CA
  10. 1.6 10km NE of Milpitas, CA
  11. 1.8 10km NE of Milpitas, CA
  12. 2.1 10km NE of Milpitas, CA
  13. 2.0 10km NE of Milpitas, CA
  14. 3.5 10km NE of Milpitas, CA
  15. 2.0 10km NE of Milpitas, 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.