QuakeIndex

Earthquake · reviewed by a seismologist

M 2.8md

6km WNW of Mountain House, CA

· 16 km deep · released about 450 lb of TNT

10 km30 km60 km120 km N Alameda County 31 kmContra Costa County 33 kmSan Joaquin County 34 kmStanislaus County 60 kmSolano County 60 kmSanta Clara County 64 kmSacramento County 76 kmSan Mateo County 79 kmSanta Cruz County 94 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 2.8 (md)
Depth
16 km below the surface
Felt
14 reports · strongest reported intensity II
Nearest
Alameda County, 31 km WSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2877 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 14 people have reported feeling it to USGS.

How big was it?

This earthquake released about 450 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 34,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 24,000× the energy of this one
  3. Around the size people start to feel M 3.0 2.1× the energy of this one
  4. This earthquake M 2.8 about 450 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 37.7952, -121.6117. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Alameda County, CA 31 km (19 mi) ENE of here earthquakes near Alameda County
Contra Costa County, CA 33 km (20 mi) ESE of here earthquakes near Contra Costa County
San Joaquin County, CA 34 km (21 mi) WSW of here earthquakes near San Joaquin County
Stanislaus County, CA 60 km (37 mi) WNW of here earthquakes near Stanislaus County
Solano County, CA 60 km (37 mi) SSE of here earthquakes near Solano County
Santa Clara County, CA 64 km (40 mi) N 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

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

  1. 1.6 14km SSE of Livermore, CA
  2. 2.1 9km NNE of Alum Rock, CA
  3. 1.5 9km NNE of Alum Rock, CA
  4. 1.8 2km NE of San Leandro, CA
  5. 2.3 2km SSE of Concord, CA
  6. 2.0 3km E of Union City, CA
  7. 1.7 5km WNW of Sunol, CA
  8. 1.7 3km WNW of Diablo, CA
  9. 2.3 8km E of Alum Rock, CA
  10. 1.7 11km SE of Livermore, CA
  11. 1.6 5km SW of Pacheco, CA
  12. 2.7 3km NNE of San Ramon, CA
  13. 2.4 1km N of Vine Hill, CA
  14. 2.4 17km ESE of Livermore, CA
  15. 2.0 1km NNE of Pacheco, 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.