QuakeIndex

Earthquake · reviewed by a seismologist

M 2.3md

2km SSE of Concord, CA

· 15 km deep · released about 74 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 5 kmAlameda County 35 kmSolano County 36 kmSan Joaquin County 64 kmMarin County 66 kmSan Mateo County 68 kmNapa County 68 kmSacramento County 80 kmYolo County 82 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 2.3 (md)
Depth
15 km below the surface
Felt
9 reports · strongest reported intensity III
Nearest
Contra Costa County, 5 km SE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2735 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 9 people have reported feeling it to USGS.

How big was it?

This earthquake released about 74 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.3 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 200,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 140,000× the energy of this one
  3. Around the size people start to feel M 3.0 13× the energy of this one
  4. This earthquake M 2.3 about 74 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 37.9495, -122.0007. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Contra Costa County, CA 5 km (3 mi) NW of here earthquakes near Contra Costa County
Alameda County, CA 35 km (21 mi) NNW of here earthquakes near Alameda County
Solano County, CA 36 km (22 mi) S of here earthquakes near Solano County
San Joaquin County, CA 64 km (40 mi) W of here earthquakes near San Joaquin County
Marin County, CA 66 km (41 mi) E of here earthquakes near Marin County
San Mateo County, CA 68 km (42 mi) NNE of here earthquakes near San Mateo County

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

Aftershocks so far

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

  1. 1.8 11km N of Bay Point, CA
  2. 1.5 2km SW of Clayton, CA
  3. 1.6 1km W of Concord, CA
  4. 1.6 13km SW of Byron, CA
  5. 1.8 2km SSW of Diablo, CA
  6. 1.5 2km SSW of Diablo, CA
  7. 2.1 13km WSW of Byron, CA
  8. 3.2 12km WSW of Byron, CA
  9. 4.3 12km WSW of Byron, CA
  10. 1.7 9km WSW of Mountain House, CA
  11. 2.1 8km WSW of Mountain House, CA
  12. 2.3 3km ESE of Berkeley, CA
  13. 1.5 3km ESE of Berkeley, CA
  14. 1.9 2km SSE of Crockett, CA
  15. 1.8 2km ENE of Pleasant Hill, 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 4.4 on 2018-01-04 — it released about 1,500 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.