QuakeIndex

Earthquake · reviewed by a seismologist

M 1.5md

3km ESE of San Ramon, CA

· 21 km deep · released about 5.4 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Alameda County 14 kmContra Costa County 16 kmSolano County 55 kmSan Mateo County 55 kmSan Joaquin County 62 kmSanta Clara County 65 kmMarin County 77 kmSanta Cruz County 85 kmStanislaus 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 1.5 (md)
Depth
21 km below the surface
Felt
no reports yet
Nearest
Alameda County, 14 km SSE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1354 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 5.4 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,800,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 2,000,000× the energy of this one
  3. Around the size people start to feel M 3.0 180× the energy of this one
  4. This earthquake M 1.5 about 5.4 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 37.7740, -121.9447. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Alameda County, CA 14 km (9 mi) NNW of here earthquakes near Alameda County
Contra Costa County, CA 16 km (10 mi) S of here earthquakes near Contra Costa County
Solano County, CA 55 km (34 mi) S of here earthquakes near Solano County
San Mateo County, CA 55 km (34 mi) NE of here earthquakes near San Mateo County
San Joaquin County, CA 62 km (38 mi) WSW of here earthquakes near San Joaquin County
Santa Clara County, CA 65 km (41 mi) NNW 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

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

  1. 2.7 3km NNE of San Leandro, CA
  2. 3.0 3km NNE of San Leandro, CA
  3. 1.6 4km SW of San Bruno, CA
  4. 2.2 4km SW of San Bruno, CA
  5. 2.3 1km ENE of Pacifica, CA
  6. 2.0 1km ENE of Pacifica, CA
  7. 2.6 1km ENE of Pacifica, CA
  8. 3.4 1km ENE of Pacifica, CA
  9. 2.3 3km NNW of Lafayette, CA
  10. 2.1 0km SSW of Crockett, CA
  11. 2.0 18km SSE of Livermore, CA
  12. 1.6 13km SSE of Livermore, CA
  13. 2.9 19km SSE of Livermore, CA
  14. 1.9 3km W of Orinda, CA
  15. 1.9 1km S of Crockett, 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 4.5 on 2019-10-15 — it released about 28,000 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.