QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

9 km SW of Brentwood, California

· 19 km deep · released about 16 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 17 kmAlameda County 28 kmSan Joaquin County 44 kmSolano County 46 kmSanta Clara County 73 kmSan Mateo County 74 kmSacramento County 74 kmStanislaus County 76 kmNapa 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 1.8 (md)
Depth
19 km below the surface
Felt
no reports yet
Nearest
Contra Costa County, 17 km WNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3485 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 16 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 930,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 660,000× the energy of this one
  3. Around the size people start to feel M 3.0 59× the energy of this one
  4. This earthquake M 1.8 about 16 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 37.8737, -121.7675. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Contra Costa County, CA 17 km (11 mi) ESE of here earthquakes near Contra Costa County
Alameda County, CA 28 km (18 mi) NNE of here earthquakes near Alameda County
San Joaquin County, CA 44 km (27 mi) W of here earthquakes near San Joaquin County
Solano County, CA 46 km (29 mi) SSE of here earthquakes near Solano County
Santa Clara County, CA 73 km (45 mi) N of here earthquakes near Santa Clara County
San Mateo County, CA 74 km (46 mi) NE of here earthquakes near San Mateo County

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

Aftershocks so far

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

  1. 1.7 1 km ESE of Pacheco, California
  2. 1.7 2 km NE of San Ramon, California
  3. 1.8 4 km ENE of Clayton, California
  4. 1.6 4 km WNW of Orinda, California
  5. 1.6 4 km NNW of Union City, California
  6. 2.5 2 km S of Piedmont, California
  7. 1.7 4 km NW of Acalanes Ridge, California
  8. 1.7 4km NW of Castro Valley, CA
  9. 3.0 1 km WSW of Kensington, California
  10. 1.6 1 km E of North Gate, California
  11. 1.8 1 km N of Pleasant Hill, California
  12. 2.3 1 km W of Danville, California
  13. 1.7 3 km SE of North Gate, California
  14. 1.5 1 km W of Concord, California
  15. 2.1 2 km SSE 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.