QuakeIndex

Earthquake · reviewed by a seismologist

M 2.5md

3 km NNW of Piedmont, California

· 5.5 km deep · released about 160 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 27 kmAlameda County 37 kmMarin County 49 kmSan Mateo County 50 kmSolano County 53 kmSan Francisco County 71 kmNapa County 73 kmSanta Clara County 85 kmSan Joaquin County 86 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
5.5 km below the surface
Felt
286 reports · strongest reported intensity IV
Nearest
Contra Costa County, 27 km ENE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3386 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 286 people have reported feeling it to USGS.

How big was it?

This earthquake released about 160 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 95,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 68,000× the energy of this one
  3. Around the size people start to feel M 3.0 6× the energy of this one
  4. This earthquake M 2.5 about 160 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 37.8528, -122.2427. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Contra Costa County, CA 27 km (17 mi) WSW of here earthquakes near Contra Costa County
Alameda County, CA 37 km (23 mi) NW of here earthquakes near Alameda County
Marin County, CA 49 km (31 mi) ESE of here earthquakes near Marin County
San Mateo County, CA 50 km (31 mi) NNE of here earthquakes near San Mateo County
Solano County, CA 53 km (33 mi) SSW of here earthquakes near Solano County
San Francisco County, CA 71 km (44 mi) ENE 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

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

  1. 1.8 1 km ENE of Pacifica, California
  2. 2.5 1 km NNW of Pleasant Hill, California
  3. 1.7 1 km ENE of Berkeley, California
  4. 2.3 2 km N of Union City, California
  5. 1.9 1 km NE of Waldon, California
  6. 1.6 1 km ESE of Pacheco, California
  7. 2.7 1 km ESE of Pacheco, California
  8. 1.6 4 km W of Pleasant Hill, California
  9. 2.1 1 km SSE of Livermore, California
  10. 2.6 2 km SSE of Livermore, California
  11. 1.9 1 km SSE of Livermore, California
  12. 1.8 2 km SSE of Livermore, California
  13. 1.6 1 km SSE of Livermore, California
  14. 1.6 1 km SSE of Livermore, California
  15. 1.6 1 km SSW of Livermore, 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.