QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

8 km S of Byron, CA

· 16 km deep · released about 16 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Alameda County 28 kmContra Costa County 30 kmSan Joaquin County 36 kmSolano County 59 kmStanislaus County 62 kmSanta Clara County 64 kmSan Mateo County 76 kmSacramento County 78 kmSanta Cruz County 93 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
16 km below the surface
Felt
no reports yet
Nearest
Alameda County, 28 km SW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1087 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 5.8 970,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 680,000× the energy of this one
  3. Around the size people start to feel M 3.0 61× 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 37.7935, -121.6467. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Alameda County, CA 28 km (18 mi) NE of here earthquakes near Alameda County
Contra Costa County, CA 30 km (19 mi) ESE of here earthquakes near Contra Costa County
San Joaquin County, CA 36 km (23 mi) WSW of here earthquakes near San Joaquin County
Solano County, CA 59 km (36 mi) SSE of here earthquakes near Solano County
Stanislaus County, CA 62 km (39 mi) WNW of here earthquakes near Stanislaus County
Santa Clara County, CA 64 km (40 mi) N 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

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

  1. 1.6 3 km E of Oakland, CA
  2. 2.7 15 km SW of Westley, CA
  3. 1.6 1 km SSE of Pacheco, CA
  4. 1.5 2 km N of Pleasant Hill, CA
  5. 1.8 1 km N of Pacheco, CA
  6. 1.6 6 km SSE of Moraga, CA
  7. 2.0 0 km E of Pacheco, CA
  8. 1.8 0 km NNW of Pacheco, CA
  9. 2.0 2 km ENE of Pleasant Hill, CA
  10. 1.6 6 km S of Isleton, CA
  11. 1.7 5 km S of San Ramon, CA
  12. 1.8 5 km S of San Ramon, CA
  13. 1.5 5 km S of San Ramon, CA
  14. 1.7 8 km SSW of Martinez, CA
  15. 2.2 5 km S of San Ramon, 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 9,400 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.