QuakeIndex

Earthquake · reviewed by a seismologist

M 3.2ml

2km NE of San Ramon, CA

· 9.5 km deep · released about 1 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 14 kmAlameda County 16 kmSolano County 53 kmSan Mateo County 55 kmSan Joaquin County 63 kmSanta Clara County 68 kmMarin County 75 kmNapa County 86 kmSanta Cruz County 87 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
9.5 km below the surface
Felt
no reports yet
Nearest
Contra Costa County, 14 km N
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1709 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

How big was it?

This earthquake released about 1 tons 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 6.7 170,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 7,400× the energy of this one
  3. Magna, Utah 2020 M 5.7 5,200× the energy of this one
  4. This earthquake M 3.2 about 1 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 2.1× 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 37.7897, -121.9628. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Contra Costa County, CA 14 km (9 mi) S of here earthquakes near Contra Costa County
Alameda County, CA 16 km (10 mi) NNW of here earthquakes near Alameda County
Solano County, CA 53 km (33 mi) S of here earthquakes near Solano County
San Mateo County, CA 55 km (34 mi) NE of here earthquakes near San Mateo County
San Joaquin County, CA 63 km (39 mi) WSW of here earthquakes near San Joaquin County
Santa Clara County, CA 68 km (42 mi) NNW of here earthquakes near Santa Clara County

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

Aftershocks so far

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

  1. 1.6 4km N of Lafayette, CA
  2. 1.6 5km N of Lafayette, CA
  3. 1.9 8km E of Fremont, CA
  4. 1.6 2km NNE of San Ramon, CA
  5. 2.4 6km N of Diablo, CA
  6. 2.1 11km SSW of Brentwood, CA
  7. 1.6 1km NE of San Ramon, CA
  8. 1.5 4km WSW of Colma, CA
  9. 1.7 5km WSW of Pacheco, CA
  10. 1.5 2km NE of Union City, CA
  11. 1.7 11km NE of Milpitas, CA
  12. 2.6 2km SW of Colma, CA
  13. 1.5 10km ENE of Milpitas, CA
  14. 1.5 2km S of Alamo, CA
  15. 2.3 4km NE of Fairview, 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 72 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.