QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

2km E of Walnut Creek, CA

· 11 km deep · released about 13 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 8 kmAlameda County 31 kmSolano County 41 kmSan Mateo County 62 kmMarin County 64 kmSan Joaquin County 67 kmNapa County 72 kmSanta Clara County 82 kmSacramento 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
11 km below the surface
Felt
1 report · strongest reported intensity II
Nearest
Contra Costa County, 8 km ENE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1524 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 1 person has reported feeling it to USGS.

How big was it?

This earthquake released about 13 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 1,200,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 840,000× the energy of this one
  3. Around the size people start to feel M 3.0 75× the energy of this one
  4. This earthquake M 1.8 about 13 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 37.9035, -122.0383. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Contra Costa County, CA 8 km (5 mi) WSW of here earthquakes near Contra Costa County
Alameda County, CA 31 km (19 mi) NNW of here earthquakes near Alameda County
Solano County, CA 41 km (26 mi) SSW of here earthquakes near Solano County
San Mateo County, CA 62 km (38 mi) NNE of here earthquakes near San Mateo County
Marin County, CA 64 km (40 mi) ESE of here earthquakes near Marin County
San Joaquin County, CA 67 km (42 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

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

  1. 2.1 9km SSW of Brentwood, CA
  2. 2.0 7km SE of Pleasanton, CA
  3. 1.7 6km SE of Pleasanton, CA
  4. 1.5 4km WSW of Antioch, CA
  5. 2.1 5km SW of Antioch, CA
  6. 1.7 6km NNW of Lafayette, CA
  7. 1.6 5km NNE of Pleasanton, CA
  8. 1.6 7km ESE of Santa Venetia, CA
  9. 1.5 10km NNE of Milpitas, CA
  10. 1.7 1km NE of Diablo, CA
  11. 1.5 2km S of Dublin, CA
  12. 1.8 2km NNW of Oakland, CA
  13. 1.9 3km WNW of Concord, CA
  14. 1.5 2km W of Concord, CA
  15. 1.7 2km WNW of Concord, 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 12,000 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.