QuakeIndex

Earthquake · reviewed by a seismologist

M 1.5md

4km E of Moraga, CA

· 3.0 km deep · released about 5.9 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 15 kmAlameda County 26 kmSolano County 49 kmSan Mateo County 54 kmMarin County 63 kmSan Joaquin County 72 kmSanta Clara County 77 kmNapa County 77 kmSan Francisco County 84 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
3.0 km below the surface
Felt
no reports yet
Nearest
Contra Costa County, 15 km NE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1476 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 5.9 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 2,500,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,800,000× the energy of this one
  3. Around the size people start to feel M 3.0 160× the energy of this one
  4. This earthquake M 1.5 about 5.9 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 37.8380, -122.0815. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Contra Costa County, CA 15 km (9 mi) SW of here earthquakes near Contra Costa County
Alameda County, CA 26 km (16 mi) NW of here earthquakes near Alameda County
Solano County, CA 49 km (31 mi) SSW of here earthquakes near Solano County
San Mateo County, CA 54 km (33 mi) NNE of here earthquakes near San Mateo County
Marin County, CA 63 km (39 mi) ESE of here earthquakes near Marin County
San Joaquin County, CA 72 km (45 mi) W of here earthquakes near San Joaquin County

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

Aftershocks so far

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

  1. 1.5 3km SSW of Clayton, CA
  2. 1.9 1km S of San Ramon, CA
  3. 1.6 9km SE of Sunol, CA
  4. 1.6 5km SW of Clayton, CA
  5. 2.8 16km SSE of Livermore, CA
  6. 1.6 6km E of Vallejo, CA
  7. 2.1 3km WNW of Crockett, CA
  8. 1.6 4km SSW of San Francisco Zoo, CA
  9. 2.1 4km WSW of Alamo, CA
  10. 2.1 6km SSW of Moraga, CA
  11. 1.9 5km SW of Pacheco, CA
  12. 1.8 2km SE of Pacheco, CA
  13. 1.6 1km S of Blackhawk, CA
  14. 2.7 0km N of Byron, CA
  15. 1.8 5km SW of San Francisco Zoo, 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 25,000 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.