QuakeIndex

Earthquake · reviewed by a seismologist

M 3.2ml

12km WSW of Byron, CA

· 12 km deep · released about 1,900 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 20 kmAlameda County 23 kmSan Joaquin County 45 kmSolano County 52 kmSanta Clara County 67 kmSan Mateo County 70 kmStanislaus County 72 kmSacramento County 79 kmMarin County 90 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 3.2 (ml)
Depth
12 km below the surface
Felt
610 reports · strongest reported intensity V
Measured shaking
intensity IV (ShakeMap)
Nearest
Contra Costa County, 20 km NW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1917 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 610 people have reported feeling it to USGS.

How big was it?

This earthquake released about 1,900 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.2 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 180,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 7,900× the energy of this one
  3. Magna, Utah 2020 M 5.7 5,600× the energy of this one
  4. This earthquake M 3.2 about 1,900 lb of TNT
  5. Around the size people start to feel M 3.0 this one released 2× more

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 37.8187, -121.7603. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Contra Costa County, CA 20 km (13 mi) ESE of here earthquakes near Contra Costa County
Alameda County, CA 23 km (14 mi) NE of here earthquakes near Alameda County
San Joaquin County, CA 45 km (28 mi) WSW of here earthquakes near San Joaquin County
Solano County, CA 52 km (32 mi) SSE of here earthquakes near Solano County
Santa Clara County, CA 67 km (41 mi) N of here earthquakes near Santa Clara County
San Mateo County, CA 70 km (44 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. 1.6 4km N of Dublin, CA
  2. 1.6 4km NNE of Dublin, CA
  3. 2.2 4km N of Dublin, CA
  4. 2.8 4km N of Dublin, CA
  5. 1.8 4km NNE of Dublin, CA
  6. 1.6 4km NNE of Dublin, CA
  7. 2.6 4km NNE of Dublin, CA
  8. 1.6 3km SW of Clayton, CA
  9. 2.3 3km NE of Orinda, CA
  10. 1.6 4km N of Dublin, CA
  11. 1.6 4km NNE of Dublin, CA
  12. 1.6 4km NNE of Dublin, CA
  13. 2.0 4km N of Dublin, CA
  14. 1.9 4km N of Dublin, CA
  15. 1.8 4km NNE of Dublin, 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 59 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.