QuakeIndex

Earthquake · reviewed by a seismologist

M 2.5md

2 km S of Piedmont, California

· 8.5 km deep · released about 140 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 28 kmAlameda County 33 kmSan Mateo County 45 kmMarin County 53 kmSolano County 57 kmSan Francisco County 71 kmNapa County 79 kmSanta Clara County 80 kmSan Joaquin County 85 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 2.5 (md)
Depth
8.5 km below the surface
Felt
23 reports · strongest reported intensity III
Nearest
Contra Costa County, 28 km ENE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3375 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 23 people have reported feeling it to USGS.

How big was it?

This earthquake released about 140 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 110,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 75,000× the energy of this one
  3. Around the size people start to feel M 3.0 6.7× the energy of this one
  4. This earthquake M 2.5 about 140 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 37.8032, -122.2292. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Contra Costa County, CA 28 km (17 mi) WSW of here earthquakes near Contra Costa County
Alameda County, CA 33 km (20 mi) WNW of here earthquakes near Alameda County
San Mateo County, CA 45 km (28 mi) NNE of here earthquakes near San Mateo County
Marin County, CA 53 km (33 mi) ESE of here earthquakes near Marin County
Solano County, CA 57 km (36 mi) SSW of here earthquakes near Solano County
San Francisco County, CA 71 km (44 mi) E of here earthquakes near San Francisco County

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

Aftershocks so far

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

  1. 1.7 3 km NNE of Danville, California
  2. 2.0 2 km ESE of Blackhawk, California
  3. 2.1 1 km ESE of Diablo, California
  4. 2.0 2 km SW of Alamo, California
  5. 2.1 4 km E of Union City, California
  6. 1.8 2 km NNE of North Gate, California
  7. 1.6 0 km ENE of North Gate, California
  8. 2.5 1 km N of Pleasant Hill, California
  9. 1.8 1 km NNW of Pleasant Hill, California
  10. 1.7 4 km NNW of Orinda, California
  11. 2.6 2 km ESE of Berkeley, California
  12. 1.9 4 km NNW of Orinda, California
  13. 1.5 Northern California
  14. 1.7 4 km W of Woodside, California
  15. 1.6 4 km SE of Piedmont, California

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.