Earthquake · reviewed by a seismologist
M 2.1md
Earthquake near Brentwood, CA
No earthquake was likely felt in Brentwood in the 24 hours to 12:08 am PST (08:08 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 2.1 earthquake was recorded 12 km (7 mi) southwest of Brentwood, CA, at 12:24 pm PDT on 3 July 2020 (19:24 UTC), 17 km deep. 1 person has reported feeling it to USGS.
USGS: 10km SW of Brentwood, CA
11 km (7 mi) SW of Brentwood, CA · 64 km (40 mi) N of San Jose, CA
- When
- 12:24 pm PDT on 3 July 2020 ()
- Where
- 12 km (7 mi) southwest of Brentwood, CA · earthquakes near Brentwood
- Magnitude
- M 2.1 (md)
- Depth
- 17 km below the surface
- Felt
- 1 report · strongest reported intensity I
- Nearest
- Contra Costa County, 14 km WNW
- Nearest mapped fault
- Greenville fault, 3 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 2318 days ago
Earthquake alerts for Brentwood, CA
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Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
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 5 km (3 mi) from the epicentre. In Brentwood, 12 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: Blackhawk, Clayton, Diablo, Byron, Antioch, Oakley.
How big was it?
This earthquake released about 44 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 340,000× the energy of this one
- Magna, Utah 2020 M 5.7 240,000× the energy of this one
- Around the size people start to feel M 3.0 22× the energy of this one
- This earthquake M 2.1 about 44 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 3,300 times the energy of this one.
Before 2016, the USGS record lists 6 earthquakes of M5 or more within 50 km; the five largest:
- 5.8 The 1980 Livermore, California Earthquake · 5 km SE of this epicentre
- 5.7 15 km NE of East Foothills, California · 45 km SSE of this epicentre
- 5.5 6 km NNE of East Foothills, California · 49 km S of this epicentre
- 5.4 South of Elmira, California · 48 km N of this epicentre
- 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 37.8700, -121.8072. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Contra Costa County, CA | 14 km (9 mi) | WNW | earthquakes near Contra Costa County |
| Alameda County, CA | 26 km (16 mi) | SSW | earthquakes near Alameda County |
| Solano County, CA | 46 km (28 mi) | NNW | earthquakes near Solano County |
| San Joaquin County, CA | 47 km (30 mi) | E | earthquakes near San Joaquin County |
| San Mateo County, CA | 71 km (44 mi) | SW | earthquakes near San Mateo County |
| Santa Clara County, CA | 73 km (45 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
59 earthquakes have been recorded within 50 km since this one.
- 1.9 7km S of Livermore, CA
- 3.3 10km NE of Milpitas, CA
- 2.9 10km NE of Milpitas, CA
- 2.7 10km NE of Milpitas, CA
- 2.1 4km ESE of Berkeley, CA
- 1.7 1km SW of Diablo, CA
- 1.9 10km NE of Milpitas, CA
- 1.6 10km NE of Milpitas, CA
- 1.8 10km NE of Milpitas, CA
- 2.1 10km NE of Milpitas, CA
- 2.0 10km NE of Milpitas, CA
- 3.5 10km NE of Milpitas, CA
- 2.0 10km NE of Milpitas, CA
- 3.4 10km NE of Milpitas, CA
- 2.3 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
- The official USGS event page — the source of record for every value above
- Did you feel it? Report it to USGS — reports go to USGS, not to us
- ShakeMap for this event, when USGS has produced one
QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.