QuakeIndex

Earthquake · reviewed by a seismologist

M 3.0ml

1km W of Concord, CA

· 15 km deep · released about 990 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 9 kmSolano County 34 kmAlameda County 37 kmMarin County 64 kmNapa County 65 kmSan Joaquin County 66 kmSan Mateo County 69 kmYolo County 80 kmSacramento 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 3.0 (ml)
Depth
15 km below the surface
Felt
728 reports · strongest reported intensity IV
Nearest
Contra Costa County, 9 km SE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1775 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 728 people have reported feeling it to USGS.

How big was it?

This earthquake released about 990 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.0 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 340,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 15,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 11,000× the energy of this one
  4. This earthquake M 3.0 about 990 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.

Where

Epicentre 37.9687, -122.0270. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Contra Costa County, CA 9 km (5 mi) NW of here earthquakes near Contra Costa County
Solano County, CA 34 km (21 mi) SSW of here earthquakes near Solano County
Alameda County, CA 37 km (23 mi) NNW of here earthquakes near Alameda County
Marin County, CA 64 km (40 mi) E of here earthquakes near Marin County
Napa County, CA 65 km (41 mi) SSE of here earthquakes near Napa County
San Joaquin County, CA 66 km (41 mi) W 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

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

  1. 1.9 5km NW of Dublin, CA
  2. 1.6 5km NW of Dublin, CA
  3. 2.1 6km WNW of Dublin, CA
  4. 2.2 5km WNW of Dublin, CA
  5. 2.0 6km WNW of Dublin, CA
  6. 2.2 5km NW of Dublin, CA
  7. 1.6 5km NW of Dublin, CA
  8. 1.9 6km SW of Clayton, CA
  9. 1.7 2km ESE of Berkeley, CA
  10. 1.8 2km ESE of Berkeley, CA
  11. 1.5 4km NW of Dublin, CA
  12. 1.6 1km ENE of Alameda, CA
  13. 1.9 1km N of East Richmond Heights, CA
  14. 1.6 2km W of Concord, CA
  15. 1.5 0km NW of Danville, 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 150 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.