QuakeIndex

Earthquake · reviewed by a seismologist

M 2.4md

6km SSW of Antioch, CA

· 20 km deep · released about 130 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 10 kmAlameda County 35 kmSolano County 36 kmSan Joaquin County 50 kmSacramento County 70 kmNapa County 75 kmSan Mateo County 76 kmMarin County 80 kmYolo County 81 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 2.4 (md)
Depth
20 km below the surface
Felt
no reports yet
Nearest
Contra Costa County, 10 km WSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1251 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

How big was it?

This earthquake released about 130 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.4 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 120,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 83,000× the energy of this one
  3. Around the size people start to feel M 3.0 7.4× the energy of this one
  4. This earthquake M 2.4 about 130 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 37.9533, -121.8398. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Contra Costa County, CA 10 km (7 mi) ENE of here earthquakes near Contra Costa County
Alameda County, CA 35 km (22 mi) N of here earthquakes near Alameda County
Solano County, CA 36 km (22 mi) SSE of here earthquakes near Solano County
San Joaquin County, CA 50 km (31 mi) W of here earthquakes near San Joaquin County
Sacramento County, CA 70 km (44 mi) SW of here earthquakes near Sacramento County
Napa County, CA 75 km (46 mi) SE of here earthquakes near Napa 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. 2.1 10 km WSW of San Lorenzo, CA
  2. 1.7 2 km ENE of San Leandro, CA
  3. 2.2 1 km NW of Green Valley, CA
  4. 2.1 4 km NNE of Fairview, CA
  5. 2.2 2 km NW of Concord, CA
  6. 1.8 1 km ENE of Pittsburg, CA
  7. 1.8 3 km WNW of Concord, CA
  8. 1.6 4 km ENE of Dublin, CA
  9. 1.6 4 km ENE of Dublin, CA
  10. 3.0 2 km NW of Alamo, CA
  11. 1.5 8 km SE of Sunol, CA
  12. 2.2 7 km SW of Brentwood, CA
  13. 2.6 8 km SW of Brentwood, CA
  14. 1.6 5 km E of Vallejo, CA
  15. 1.6 2 km NW of Pittsburg, 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 1,100 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.