QuakeIndex

Earthquake · reviewed by a seismologist

M 2.8md

3km WNW of Diablo, CA

· 6.9 km deep · released about 400 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 9 kmAlameda County 23 kmSolano County 47 kmSan Mateo County 59 kmSan Joaquin County 63 kmMarin County 71 kmSanta Clara County 74 kmNapa County 80 kmSacramento County 88 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
6.9 km below the surface
Felt
124 reports · strongest reported intensity IV
Nearest
Contra Costa County, 9 km NNE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3138 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 124 people have reported feeling it to USGS.

How big was it?

This earthquake released about 400 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 38,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 27,000× the energy of this one
  3. Around the size people start to feel M 3.0 2.4× the energy of this one
  4. This earthquake M 2.8 about 400 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 37.8437, -121.9853. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Contra Costa County, CA 9 km (6 mi) SSW of here earthquakes near Contra Costa County
Alameda County, CA 23 km (14 mi) NNW of here earthquakes near Alameda County
Solano County, CA 47 km (29 mi) S of here earthquakes near Solano County
San Mateo County, CA 59 km (36 mi) NE of here earthquakes near San Mateo County
San Joaquin County, CA 63 km (39 mi) W of here earthquakes near San Joaquin County
Marin County, CA 71 km (44 mi) ESE of here earthquakes near Marin 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. 3.8 9km NNE of Alum Rock, CA
  2. 1.9 9km NE of Milpitas, CA
  3. 1.7 2km NW of Castro Valley, CA
  4. 2.1 4km ESE of San Ramon, CA
  5. 2.8 2km E of Pacheco, CA
  6. 2.6 12km WNW of Rio Vista, CA
  7. 2.7 0km WNW of Diablo, CA
  8. 1.7 2km WSW of Diablo, CA
  9. 1.6 10km NE of Milpitas, CA
  10. 1.8 3km NNE of Fremont, CA
  11. 2.2 1km NE of San Leandro, CA
  12. 1.6 9km SSW of Brentwood, CA
  13. 2.4 8km SSW of Brentwood, CA
  14. 1.6 0km WNW of Diablo, CA
  15. 1.6 2km W of Diablo, 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 280 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.