QuakeIndex

Earthquake · reviewed by a seismologist

M 2.3md

3km NE of Orinda, CA

· 6.7 km deep · released about 74 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 18 kmAlameda County 35 kmSolano County 45 kmMarin County 54 kmSan Mateo County 57 kmNapa County 69 kmSan Joaquin County 78 kmSan Francisco County 79 kmSanta Clara County 86 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 2.3 (md)
Depth
6.7 km below the surface
Felt
59 reports · strongest reported intensity IV
Nearest
Contra Costa County, 18 km E
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2525 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 59 people have reported feeling it to USGS.

How big was it?

This earthquake released about 74 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.3 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 200,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 140,000× the energy of this one
  3. Around the size people start to feel M 3.0 13× the energy of this one
  4. This earthquake M 2.3 about 74 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 37.8980, -122.1570. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Contra Costa County, CA 18 km (11 mi) W of here earthquakes near Contra Costa County
Alameda County, CA 35 km (22 mi) NW of here earthquakes near Alameda County
Solano County, CA 45 km (28 mi) SSW of here earthquakes near Solano County
Marin County, CA 54 km (34 mi) ESE of here earthquakes near Marin County
San Mateo County, CA 57 km (35 mi) NNE of here earthquakes near San Mateo County
Napa County, CA 69 km (43 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

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

  1. 1.7 3km WSW of San Francisco Zoo, CA
  2. 2.1 2km ENE of Pleasant Hill, CA
  3. 1.7 3km SSW of American Canyon, CA
  4. 2.1 1km ENE of El Cerrito, CA
  5. 1.9 2km SSW of Pleasant Hill, CA
  6. 2.1 1km S of Pleasant Hill, CA
  7. 2.5 4km SE of Oakland, CA
  8. 1.8 5km SSW of Port Costa, CA
  9. 1.9 6km NE of Alamo, CA
  10. 1.6 8km WNW of San Francisco Zoo, CA
  11. 2.0 4km N of Dublin, CA
  12. 1.6 4km N of Dublin, CA
  13. 2.1 4km N of Dublin, CA
  14. 1.6 2km N of Danville, CA
  15. 1.8 2km ESE of Alamo, 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 1,500 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.