QuakeIndex

Earthquake · reviewed by a seismologist

M 2.2md

2 km ENE of Discovery Bay, CA

· 22 km deep · released about 64 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N San Joaquin County 27 kmContra Costa County 33 kmAlameda County 42 kmSolano County 50 kmSacramento County 63 kmStanislaus County 64 kmSanta Clara County 78 kmYolo County 89 kmSan Mateo County 89 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 2.2 (md)
Depth
22 km below the surface
Felt
no reports yet
Nearest
San Joaquin County, 27 km E
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 605 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

How big was it?

This earthquake released about 64 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.2 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 230,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 170,000× the energy of this one
  3. Around the size people start to feel M 3.0 15× the energy of this one
  4. This earthquake M 2.2 about 64 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 37.9177, -121.5790. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
San Joaquin County, CA 27 km (17 mi) W of here earthquakes near San Joaquin County
Contra Costa County, CA 33 km (20 mi) E of here earthquakes near Contra Costa County
Alameda County, CA 42 km (26 mi) NE of here earthquakes near Alameda County
Solano County, CA 50 km (31 mi) SE of here earthquakes near Solano County
Sacramento County, CA 63 km (39 mi) SSW of here earthquakes near Sacramento County
Stanislaus County, CA 64 km (40 mi) NW of here earthquakes near Stanislaus County

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

Aftershocks so far

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

  1. 1.9 1 km SSE of Walnut Creek, CA
  2. 1.7 5 km W of Dublin, CA
  3. 1.9 8 km SW of Mountain House, CA
  4. 1.7 12 km W of Rio Vista, CA
  5. 1.6 12 km NE of Pittsburg, CA
  6. 2.9 13 km NNE of Pittsburg, CA
  7. 2.3 12 km NNE of Pittsburg, CA
  8. 2.1 12 km W of Rio Vista, CA
  9. 1.8 12 km W of Rio Vista, CA
  10. 2.9 5 km WNW of Dublin, CA
  11. 1.7 9 km E of Blackhawk, CA
  12. 1.7 2 km ENE of Lafayette, CA
  13. 1.8 3 km SW of Blackhawk, CA
  14. 2.5 5 km WNW of Dublin, CA
  15. 1.6 4 km WNW 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 4.5 on 2019-10-15 — it released about 2,300 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.