QuakeIndex

Earthquake · reviewed by a seismologist

M 2.7md

6 km ESE of Clayton, CA

· 6.2 km deep · released about 350 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 8 kmAlameda County 33 kmSolano County 37 kmSan Joaquin County 52 kmSacramento County 73 kmSan Mateo County 73 kmNapa County 75 kmMarin County 78 kmSanta Clara 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 2.7 (md)
Depth
6.2 km below the surface
Felt
76 reports · strongest reported intensity III
Nearest
Contra Costa County, 8 km WSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 401 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 76 people have reported feeling it to USGS.

How big was it?

This earthquake released about 350 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 43,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 31,000× the energy of this one
  3. Around the size people start to feel M 3.0 2.7× the energy of this one
  4. This earthquake M 2.7 about 350 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 37.9400, -121.8672. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Contra Costa County, CA 8 km (5 mi) ENE of here earthquakes near Contra Costa County
Alameda County, CA 33 km (20 mi) N of here earthquakes near Alameda County
Solano County, CA 37 km (23 mi) S of here earthquakes near Solano County
San Joaquin County, CA 52 km (32 mi) W of here earthquakes near San Joaquin County
Sacramento County, CA 73 km (45 mi) SW of here earthquakes near Sacramento County
San Mateo County, CA 73 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

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

  1. 1.7 3 km ESE of Berkeley, CA
  2. 2.9 3 km SE of Berkeley, CA
  3. 2.6 3 km SE of Berkeley, CA
  4. 2.1 3 km ESE of Berkeley, CA
  5. 4.3 2 km ESE of Berkeley, CA
  6. 1.6 10 km ENE of Blackhawk, CA
  7. 1.6 9 km W of Brentwood, CA
  8. 1.6 2 km ENE of Oakland, CA
  9. 1.9 3 km SW of Clayton, CA
  10. 1.9 8 km ESE of Clayton, CA
  11. 3.3 8 km E of Clayton, CA
  12. 1.6 7 km ENE of Vallejo, CA
  13. 1.6 4 km ESE of Vallejo, CA
  14. 2.1 5 km N of Pleasanton, CA
  15. 1.5 4 km NNE of Pleasanton, 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 420 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.