QuakeIndex

Earthquake · reviewed by a seismologist

M 2.9ml

3 km SW of Discovery Bay, CA

· 2.2 km deep · released about 630 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 29 kmSan Joaquin County 31 kmAlameda County 37 kmSolano County 50 kmStanislaus County 65 kmSacramento County 67 kmSanta Clara County 75 kmSan Mateo County 85 kmYolo County 91 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 2.9 (ml)
Depth
2.2 km below the surface
Felt
163 reports · strongest reported intensity V
Nearest
Contra Costa County, 29 km W
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 870 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 163 people have reported feeling it to USGS.

How big was it?

This earthquake released about 630 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 24,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 17,000× the energy of this one
  3. Around the size people start to feel M 3.0 1.5× the energy of this one
  4. This earthquake M 2.9 about 630 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 37.8912, -121.6198. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Contra Costa County, CA 29 km (18 mi) E of here earthquakes near Contra Costa County
San Joaquin County, CA 31 km (19 mi) W of here earthquakes near San Joaquin County
Alameda County, CA 37 km (23 mi) NE of here earthquakes near Alameda County
Solano County, CA 50 km (31 mi) SE of here earthquakes near Solano County
Stanislaus County, CA 65 km (41 mi) NW of here earthquakes near Stanislaus County
Sacramento County, CA 67 km (41 mi) SSW of here earthquakes near Sacramento 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 8 km N of Livermore, CA
  2. 2.6 7 km SW of Brentwood, CA
  3. 2.6 10 km E of Blackhawk, CA
  4. 1.5 3 km ESE of Hayward, CA
  5. 1.7 3 km E of Hayward, CA
  6. 2.4 10 km SE of Sunol, CA
  7. 1.7 2 km NE of San Leandro, CA
  8. 2.1 9 km E of Blackhawk, CA
  9. 1.7 9 km E of Blackhawk, CA
  10. 2.9 10 km E of Blackhawk, CA
  11. 1.6 13 km SSE of Livermore, CA
  12. 1.6 13 km SSE of Livermore, CA
  13. 2.5 13 km SSE of Livermore, CA
  14. 1.6 5 km NNE of Fairview, CA
  15. 1.7 7 km SW of Brentwood, 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 230 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.