QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

2km ESE of Discovery Bay, CA

· 7.4 km deep · released about 14 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 40 kmSolano County 52 kmStanislaus County 63 kmSacramento County 65 kmSanta Clara County 76 kmSan Mateo County 88 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 1.8 (md)
Depth
7.4 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 3008 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 14 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,100,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 790,000× the energy of this one
  3. Around the size people start to feel M 3.0 70× the energy of this one
  4. This earthquake M 1.8 about 14 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 37.8995, -121.5803. 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 40 km (25 mi) NE of here earthquakes near Alameda County
Solano County, CA 52 km (32 mi) SE of here earthquakes near Solano County
Stanislaus County, CA 63 km (39 mi) NW of here earthquakes near Stanislaus County
Sacramento County, CA 65 km (40 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

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

  1. 1.6 5km E of Fremont, CA
  2. 2.6 8km SE of Sunol, CA
  3. 2.3 3km E of Pacheco, CA
  4. 1.6 2km ESE of Pleasanton, CA
  5. 1.7 6km NE of Blackhawk, CA
  6. 1.6 6km WNW of Mountain House, CA
  7. 2.8 6km WNW of Mountain House, CA
  8. 1.5 16km SSE of Livermore, CA
  9. 1.6 2km W of Diablo, CA
  10. 1.8 2km NE of San Ramon, CA
  11. 2.0 14km N of Pittsburg, CA
  12. 2.2 1km NNW of Alamo, CA
  13. 1.6 2km SW of Diablo, CA
  14. 1.7 3km NW of Diablo, CA
  15. 2.3 16km SSE of Livermore, 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.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.