QuakeIndex

Earthquake · reviewed by a seismologist

M 2.5md

Earthquake near San Leandro, CA

No earthquake was likely felt in San Leandro in the 24 hours to 4:08 am PST (12:08 UTC). The last one was M 2.6, 18 km (11 mi) NNW, at 6:23 pm PST on 1 November 2026, estimated intensity II (weak) in town; 114 felt reports to USGS. Every earthquake near San Leandro

This page: a magnitude 2.5 earthquake was recorded 4 km (3 mi) north of San Leandro, CA, at 6:08 pm PST on 4 December 2021 (02:08 UTC), 2.8 km deep. 150 people have reported feeling it to USGS.

USGS: 4km N of San Leandro, CA

6 km (4 mi) E of Oakland, CA

6:08 pm PST, Dec 4, 2021 · · 2.8 km deep · released about 180 lb of TNT

10 km30 km60 km120 km N Alameda County 25 kmContra Costa County 25 kmSan Mateo County 43 kmSolano County 59 kmMarin County 61 kmSanta Clara County 73 kmSan Francisco County 77 kmSan Joaquin County 80 kmNapa 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
6:08 pm PST on 4 December 2021 ()
Where
4 km (3 mi) north of San Leandro, CA · earthquakes near San Leandro
Magnitude
M 2.5 (md)
Depth
2.8 km below the surface
Felt
150 reports · strongest reported intensity IV
Nearest
Alameda County, 25 km ESE
Nearest mapped fault
Hayward fault, 1 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 1734 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 22 km (14 mi) from the epicentre. In San Leandro, 4 km away, the estimate is intensity III (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: San Leandro 4 km, intensity III · Alameda 9 km, intensity III · Castro Valley 10 km, intensity III · San Lorenzo 10 km, intensity III · Oakland 11 km, intensity II · Hayward 12 km, intensity II · Orinda 13 km, intensity II · Lafayette 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 180 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 83,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 59,000× the energy of this one
  3. Around the size people start to feel M 3.0 5.2× the energy of this one
  4. This earthquake M 2.5 about 180 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 810 times the energy of this one.

Before 2016, the USGS record lists 6 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.9 The 1906 San Francisco, California Earthquake · 35 km W of this epicentre
  2. 5.8 The 1980 Livermore, California Earthquake · 35 km ENE of this epicentre
  3. 5.5 6 km NNE of East Foothills, California · 50 km SE of this epicentre
  4. 5.4 9 km NE of Livermore, California · 40 km E of this epicentre
  5. 5.3 The 1957 San Francisco, California Earthquake · 31 km WSW 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 37.7623, -122.1575. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Alameda County, CA 25 km (16 mi) ESE earthquakes near Alameda County
Contra Costa County, CA 25 km (16 mi) NE earthquakes near Contra Costa County
San Mateo County, CA 43 km (27 mi) SSW earthquakes near San Mateo County
Solano County, CA 59 km (37 mi) NNE earthquakes near Solano County
Marin County, CA 61 km (38 mi) WNW earthquakes near Marin County
Santa Clara County, CA 73 km (45 mi) SE earthquakes near Santa Clara 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. 2.0 1km NW of Concord, CA
  2. 1.6 2km NNE of Danville, CA
  3. 1.7 6km WSW of Daly City, CA
  4. 2.3 5km E of Blackhawk, CA
  5. 1.6 4km E of South San Francisco, CA
  6. 1.9 3km ESE of Pacheco, CA
  7. 1.7 2km SSW of Blackhawk, CA
  8. 1.5 5km WSW of Daly City, CA
  9. 1.6 2km NE of Union City, CA
  10. 1.8 3km ENE of San Leandro, CA
  11. 2.9 3km ENE of San Leandro, CA
  12. 1.6 2km ENE of Pacifica, CA
  13. 3.2 2km NNE of San Leandro, CA
  14. 1.6 5km WNW of Byron, CA
  15. 1.7 5km WNW of Byron, 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.