QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

4 km ENE of Clayton, California

· 16 km deep · released about 14 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 7 kmAlameda County 34 kmSolano County 35 kmSan Joaquin County 54 kmSacramento County 73 kmNapa County 73 kmSan Mateo County 74 kmMarin County 76 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 1.8 (md)
Depth
16 km below the surface
Felt
no reports yet
Nearest
Contra Costa County, 7 km WSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3358 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 14 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,100,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 790,000× the energy of this one
  3. Around the size people start to feel M 3.0 70× the energy of this one
  4. This earthquake M 1.8 about 14 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 37.9512, -121.8828. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Contra Costa County, CA 7 km (4 mi) ENE of here earthquakes near Contra Costa County
Alameda County, CA 34 km (21 mi) N of here earthquakes near Alameda County
Solano County, CA 35 km (22 mi) S of here earthquakes near Solano County
San Joaquin County, CA 54 km (33 mi) W of here earthquakes near San Joaquin County
Sacramento County, CA 73 km (45 mi) SW of here earthquakes near Sacramento County
Napa County, CA 73 km (45 mi) SSE of here earthquakes near Napa County

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

Aftershocks so far

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

  1. 2.9 15 km SSE of Livermore, California
  2. 2.3 15 km SSE of Livermore, California
  3. 1.7 11 km SSE of Livermore, California
  4. 1.6 2 km W of Danville, California
  5. 2.0 2 km WSW of Clyde, California
  6. 2.0 6 km NW of Bayview, California
  7. 1.7 1 km SSW of Clyde, California
  8. 1.7 1 km SW of Clyde, California
  9. 2.3 2 km WSW of Clyde, California
  10. 1.5 1 km SSE of Clyde, California
  11. 1.7 1 km WNW of Concord, California
  12. 1.9 3 km SE of Rodeo, California
  13. 1.7 7 km W of San Ramon, California
  14. 2.7 8 km SE of Livermore, California
  15. 1.9 7 km SE of Livermore, 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.