QuakeIndex

Earthquake · reviewed by a seismologist

M 1.9md

9 km S of Antioch, California

· 4.3 km deep · released about 18 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 12 kmAlameda County 31 kmSolano County 41 kmSan Joaquin County 48 kmSacramento County 72 kmSan Mateo County 74 kmSanta Clara County 78 kmNapa County 79 kmStanislaus 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 1.9 (md)
Depth
4.3 km below the surface
Felt
no reports yet
Nearest
Contra Costa County, 12 km W
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3505 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 18 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 840,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 600,000× the energy of this one
  3. Around the size people start to feel M 3.0 53× the energy of this one
  4. This earthquake M 1.9 about 18 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 37.9160, -121.8158. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Contra Costa County, CA 12 km (7 mi) E of here earthquakes near Contra Costa County
Alameda County, CA 31 km (19 mi) NNE of here earthquakes near Alameda County
Solano County, CA 41 km (25 mi) SSE of here earthquakes near Solano County
San Joaquin County, CA 48 km (30 mi) W of here earthquakes near San Joaquin County
Sacramento County, CA 72 km (45 mi) SW of here earthquakes near Sacramento County
San Mateo County, CA 74 km (46 mi) NE 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

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

  1. 1.6 4 km NNW of Union City, California
  2. 2.5 2 km S of Piedmont, California
  3. 1.7 4 km NW of Acalanes Ridge, California
  4. 1.7 4km NW of Castro Valley, CA
  5. 3.0 1 km WSW of Kensington, California
  6. 1.6 1 km E of North Gate, California
  7. 1.8 1 km N of Pleasant Hill, California
  8. 2.3 1 km W of Danville, California
  9. 1.7 3 km SE of North Gate, California
  10. 1.5 1 km W of Concord, California
  11. 2.1 2 km SSE of Livermore, California
  12. 1.6 0 km N of Contra Costa Centre, California
  13. 2.3 1 km ENE of Pacheco, California
  14. 2.1 1 km N of Pleasant Hill, California
  15. 2.5 1 km NNW of Pleasant Hill, California

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

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