QuakeIndex

Earthquake · reviewed by a seismologist

M 2.3md

Earthquake near Walnut Creek, CA

No earthquake was likely felt in Walnut Creek in the 24 hours to 3:57 am PST (11:57 UTC). The last one was M 2.1, 4 km (2 mi) N, at 4:05 am PST on 8 November 2026, estimated intensity II (weak) in town; 3 felt reports to USGS. Every earthquake near Walnut Creek

This page: a magnitude 2.3 earthquake was recorded 4 km (2 mi) east-northeast of Walnut Creek, CA, at 5:52 am PST on 7 January 2021 (13:52 UTC), 9.9 km deep. 28 people have reported feeling it to USGS.

USGS: 4km ENE of Walnut Creek, CA

in Walnut Creek, CA · 38 km (23 mi) ENE of San Francisco, CA

5:52 am PST, Jan 7, 2021 · · 9.9 km deep · released about 85 lb of TNT

10 km30 km60 km120 km N Contra Costa County 7 kmAlameda County 32 kmSolano County 39 kmSan Mateo County 64 kmMarin County 64 kmSan Joaquin County 66 kmNapa County 70 kmSanta Clara County 83 kmSacramento 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
5:52 am PST on 7 January 2021 ()
Where
4 km (2 mi) east-northeast of Walnut Creek, CA · earthquakes near Walnut Creek
Magnitude
M 2.3 (md)
Depth
9.9 km below the surface
Felt
28 reports · strongest reported intensity IV
Nearest
Contra Costa County, 7 km E
Nearest mapped fault
Concord fault, 6 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 1461 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 17 km (11 mi) from the epicentre. In Walnut Creek, 4 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: Walnut Creek 4 km, intensity II · Pleasant Hill 4 km, intensity II · Concord 6 km, intensity II · Alamo 8 km, intensity II · Pacheco 8 km, intensity II · Lafayette 9 km, intensity II · Danville 11 km, intensity II · Orinda 14 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 85 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 5.8 180,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 130,000× the energy of this one
  3. Around the size people start to feel M 3.0 11× the energy of this one
  4. This earthquake M 2.3 about 85 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 1,700 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 · 50 km WSW of this epicentre
  2. 6.0 The 2014 South Napa, California Earthquake · 41 km NW of this epicentre
  3. 5.8 The 1980 Livermore, California Earthquake · 25 km ESE of this epicentre
  4. 5.4 South of Elmira, California · 44 km NNE of this epicentre
  5. 5.4 9 km NE of Livermore, California · 34 km SE 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 37.9213, -122.0295. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Contra Costa County, CA 7 km (4 mi) E earthquakes near Contra Costa County
Alameda County, CA 32 km (20 mi) SSE earthquakes near Alameda County
Solano County, CA 39 km (24 mi) NNE earthquakes near Solano County
San Mateo County, CA 64 km (40 mi) SSW earthquakes near San Mateo County
Marin County, CA 64 km (40 mi) WNW earthquakes near Marin County
San Joaquin County, CA 66 km (41 mi) E earthquakes near San Joaquin County

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

Aftershocks so far

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

  1. 2.8 2km N of Piedmont, CA
  2. 1.5 5km E of Vallejo, CA
  3. 1.7 7km W of Newark, CA
  4. 2.5 2km N of Piedmont, CA
  5. 1.8 3km WSW of Oakley, CA
  6. 1.9 10km SSE of Elmira, CA
  7. 1.8 3km S of Concord, CA
  8. 2.2 14km SE of Livermore, CA
  9. 2.3 14km SE of Livermore, CA
  10. 2.9 14km SE of Livermore, CA
  11. 1.6 6km ESE of Santa Venetia, CA
  12. 1.8 1km SW of East Richmond Heights, CA
  13. 2.4 0km W of Pleasant Hill, CA
  14. 2.1 4km WSW of Pleasanton, CA
  15. 1.7 10km SE of Sunol, 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.