QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6md

Earthquake near Alameda, CA

No earthquake was likely felt in Alameda in the 24 hours to 7:07 am PST (15:07 UTC). The last one was M 2.6, 11 km (7 mi) N, at 6:23 pm PST on 1 November 2026, estimated intensity II (weak) in town; 114 felt reports to USGS. Every earthquake near Alameda

This page: a magnitude 1.6 earthquake was recorded 2 km (2 mi) east of Alameda, CA, at 10:05 am PDT on 14 May 2021 (17:05 UTC), 7.1 km deep.

USGS: 1km ENE of Alameda, CA

in Oakland, CA

10:05 am PDT, May 14, 2021 · · 7.1 km deep · released about 6.8 lb of TNT

10 km30 km60 km120 km N Contra Costa County 30 kmAlameda County 31 kmSan Mateo County 41 kmMarin County 55 kmSolano County 61 kmSan Francisco County 70 kmSanta Clara County 77 kmNapa County 82 kmSan Joaquin 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
10:05 am PDT on 14 May 2021 ()
Where
2 km (2 mi) east of Alameda, CA · earthquakes near Alameda
Magnitude
M 1.6 (md)
Depth
7.1 km below the surface
Felt
no reports yet
Nearest
Contra Costa County, 30 km NE
Nearest mapped fault
Hayward fault, 5 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 2004 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 8 km (5 mi) from the epicentre. In Alameda, 2 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: Alameda 2 km, intensity II · Oakland 5 km, intensity II · San Leandro 8 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 6.8 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,200,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,600,000× the energy of this one
  3. Around the size people start to feel M 3.0 140× the energy of this one
  4. This earthquake M 1.6 about 6.8 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 22,000 times the energy of this one.

Before 2016, the USGS record lists 5 earthquakes of M5 or more within 50 km:

  1. 7.9 The 1906 San Francisco, California Earthquake · 28 km W of this epicentre
  2. 5.8 The 1980 Livermore, California Earthquake · 42 km E of this epicentre
  3. 5.4 9 km NE of Livermore, California · 46 km E of this epicentre
  4. 5.3 The 1957 San Francisco, California Earthquake · 25 km WSW of this epicentre
  5. 5.1 11 km E of Blackhawk, California · 41 km E 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 37.7688, -122.2328. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Contra Costa County, CA 30 km (19 mi) NE earthquakes near Contra Costa County
Alameda County, CA 31 km (19 mi) ESE earthquakes near Alameda County
San Mateo County, CA 41 km (26 mi) SSW earthquakes near San Mateo County
Marin County, CA 55 km (34 mi) NW earthquakes near Marin County
Solano County, CA 61 km (38 mi) NNE earthquakes near Solano County
San Francisco County, CA 70 km (44 mi) W earthquakes near San Francisco County

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

Aftershocks so far

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

  1. 2.4 5km SE of Portola Valley, CA
  2. 1.5 2km ESE of Berkeley, CA
  3. 1.9 11km NE of Milpitas, CA
  4. 1.5 4km E of Moraga, CA
  5. 1.8 7km S of Muir Beach, CA
  6. 2.2 4km NNE of Blackhawk, CA
  7. 2.5 4km NNE of Blackhawk, CA
  8. 2.0 4km NE of Blackhawk, CA
  9. 1.9 4km SSW of Colma, CA
  10. 2.3 2km WNW of Concord, CA
  11. 1.7 2km E of Berkeley, CA
  12. 1.8 5km E of Fremont, CA
  13. 2.1 8km S of Muir Beach, CA
  14. 1.6 8km S of Muir Beach, CA
  15. 1.6 3km NNW of Piedmont, 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.