QuakeIndex

Earthquake · reviewed by a seismologist

M 4.1mw

7km NW of Bay Point, CA

· 18 km deep · released about 24 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 18 kmSolano County 22 kmAlameda County 48 kmNapa County 55 kmMarin County 65 kmSan Joaquin County 66 kmYolo County 68 kmSacramento County 71 kmSan Mateo County 80 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
Magnitude
M 4.1 (mw)
Depth
18 km below the surface
Felt
5794 reports · strongest reported intensity IV
Measured shaking
intensity IV (ShakeMap)
USGS impact alert
green
Tsunami
USGS flagged this event for tsunami evaluation. Follow tsunami.gov for official messages.
Nearest
Contra Costa County, 18 km SSE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 614 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon. 5794 people have reported feeling it to USGS.

How big was it?

This earthquake released about 24 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.1 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 6,900× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 310× the energy of this one
  3. Magna, Utah 2020 M 5.7 220× the energy of this one
  4. This earthquake M 4.1 about 24 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 51× 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.

Where

Epicentre 38.0765, -122.0077. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Contra Costa County, CA 18 km (11 mi) NNW of here earthquakes near Contra Costa County
Solano County, CA 22 km (14 mi) SSW of here earthquakes near Solano County
Alameda County, CA 48 km (30 mi) N of here earthquakes near Alameda County
Napa County, CA 55 km (34 mi) SSE of here earthquakes near Napa County
Marin County, CA 65 km (40 mi) E of here earthquakes near Marin County
San Joaquin County, CA 66 km (41 mi) WNW of here earthquakes near San Joaquin County

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

Aftershocks so far

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

  1. 1.7 2km WNW of Concord, CA
  2. 2.1 2km NNE of San Leandro, CA
  3. 1.7 4km WNW of Dublin, CA
  4. 1.5 7km E of Santa Venetia, CA
  5. 1.9 8km WSW of Mountain House, CA
  6. 2.1 6km NW of Bay Point, CA
  7. 1.9 2km ENE of Berkeley, CA
  8. 1.6 6km SSW of Suisun City, CA
  9. 1.8 2km SE of Pacheco, CA
  10. 1.7 3km ESE of Berkeley, CA
  11. 2.0 3km ESE of Berkeley, CA
  12. 1.7 5km E of Vallejo, CA
  13. 2.4 3km ESE of Berkeley, CA
  14. 2.9 3km ESE of Berkeley, CA
  15. 2.7 4km E of Sonoma, 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.

For this area

The largest earthquake within 50 km in our catalogue was M 4.5 on 2019-10-15 — it released about 3 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

On USGS

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