QuakeIndex

Earthquake · reviewed by a seismologist

M 2.3md

Earthquake near Lafayette, CA

No earthquake was likely felt in Lafayette in the 24 hours to 12:50 am PST (08:50 UTC). The last one was M 2.1, 8 km (5 mi) NE, at 4:05 am PST on 8 November 2026, estimated intensity II (weak) in town; 3 felt reports to USGS. Every earthquake near Lafayette

This page: a magnitude 2.3 earthquake was recorded 3 km (2 mi) north-northwest of Lafayette, CA, at 5:03 pm PDT on 26 March 2023 (00:03 UTC), 12 km deep. 9 people have reported feeling it to USGS.

USGS: 3km NNW of Lafayette, CA

29 km (18 mi) ENE of San Francisco, CA · 8 km (5 mi) W of Walnut Creek, CA

5:03 pm PDT, Mar 26, 2023 · · 12 km deep · released about 91 lb of TNT

10 km30 km60 km120 km N Contra Costa County 16 kmAlameda County 35 kmSolano County 43 kmMarin County 56 kmSan Mateo County 59 kmNapa County 68 kmSan Joaquin County 76 kmSan Francisco County 81 kmSanta Clara 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
5:03 pm PDT on 26 March 2023 ()
Where
3 km (2 mi) north-northwest of Lafayette, CA · earthquakes near Lafayette
Magnitude
M 2.3 (md)
Depth
12 km below the surface
Felt
9 reports · strongest reported intensity III
Nearest
Contra Costa County, 16 km E
Nearest mapped fault
Hayward fault, 11 km from its surface trace — near is not the same as on
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 416 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 16 km (10 mi) from the epicentre. In Lafayette, 3 km away, the estimate is intensity II (weak). Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

Likely felt in: Lafayette 3 km, intensity II · Orinda 5 km, intensity II · Walnut Creek 6 km, intensity II · Pleasant Hill 8 km, intensity II · Pacheco 10 km, intensity II · Alamo 11 km, intensity II · Concord 12 km, intensity II · Martinez 12 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 91 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.3 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 170,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 120,000× the energy of this one
  3. Around the size people start to feel M 3.0 10× the energy of this one
  4. This earthquake M 2.3 about 91 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.

For this area

The largest earthquake within 50 km since 2016 was M 4.5 on 2019-10-15 — about 1,600 times the energy of this one.

Before 2016, the USGS record lists 7 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.9 The 1906 San Francisco, California Earthquake · 41 km WSW of this epicentre
  2. 6.0 The 2014 South Napa, California Earthquake · 37 km NNW of this epicentre
  3. 5.8 The 1980 Livermore, California Earthquake · 33 km ESE of this epicentre
  4. 5.4 South of Elmira, California · 48 km NNE of this epicentre
  5. 5.4 9 km NE of Livermore, California · 42 km ESE of this epicentre

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Epicentre 37.9113, -122.1362. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Contra Costa County, CA 16 km (10 mi) E earthquakes near Contra Costa County
Alameda County, CA 35 km (22 mi) SE earthquakes near Alameda County
Solano County, CA 43 km (27 mi) NNE earthquakes near Solano County
Marin County, CA 56 km (35 mi) WNW earthquakes near Marin County
San Mateo County, CA 59 km (37 mi) SSW earthquakes near San Mateo County
Napa County, CA 68 km (42 mi) NNW earthquakes near Napa County

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

Aftershocks so far

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

  1. 1.8 7km ENE of Vallejo, CA
  2. 1.8 2km N of Lafayette, CA
  3. 2.2 5km WSW of San Francisco Zoo, CA
  4. 1.7 4km SW of Vallejo, CA
  5. 2.2 4km E of Walnut Creek, CA
  6. 1.7 5km E of Walnut Creek, CA
  7. 2.1 6km NNE of San Leandro, CA
  8. 2.2 6km SSW of Antioch, CA
  9. 1.9 1km SSE of Diablo, CA
  10. 1.6 4km NNW of Diablo, CA
  11. 1.6 3km N of Danville, CA
  12. 1.6 2km E of Union City, CA
  13. 2.2 2km ENE of Union City, CA
  14. 1.5 8km SSW of Antioch, CA
  15. 1.6 2km S of Blackhawk, 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.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.