QuakeIndex

Earthquake · reviewed by a seismologist

M 1.5md

Earthquake near Alameda, CA

Yes. A magnitude 1.5 earthquake was recorded 6 km (3 mi) E of Alameda, CA, at 10:40 pm PDT on 18 September 2016 (05:40 UTC), 12 km deep.

This was on 18 September 2016. The latest near Alameda: M 2.5 on 17 August 2026.

USGS: 5 km E of Alameda, California

in Oakland, CA

10:40 pm PDT, Sep 18, 2016 · · 12 km deep · released about 5.7 lb of TNT

10 km30 km60 km120 km N Contra Costa County 27 kmAlameda County 29 kmSan Mateo County 43 kmMarin County 57 kmSolano County 59 kmSan Francisco County 74 kmSanta Clara County 76 kmNapa County 82 kmSan Joaquin County 83 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
10:40 pm PDT on 18 September 2016 ()
Where
6 km (3 mi) E of Alameda, CA · earthquakes near Alameda
Magnitude
M 1.5 (md)
Depth
12 km below the surface
Felt
no reports yet
Nearest
Contra Costa County, 27 km NE
Nearest mapped fault
Hayward fault, 2 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 3531 days ago

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

At this magnitude and depth it was probably too small to be felt, even directly above it. In Alameda, 6 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.

Earthquakes near other towns within 30 km: Piedmont, San Leandro, Oakland, Moraga, Emeryville, Orinda.

How big was it?

This earthquake released about 5.7 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,600,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,900,000× the energy of this one
  3. Around the size people start to feel M 3.0 170× the energy of this one
  4. This earthquake M 1.5 about 5.7 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

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

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 · 31 km W of this epicentre
  2. 6.0 The 2014 South Napa, California Earthquake · 50 km NNW of this epicentre
  3. 5.8 The 1980 Livermore, California Earthquake · 38 km E of this epicentre
  4. 5.4 9 km NE of Livermore, California · 43 km E of this epicentre
  5. 5.3 The 1957 San Francisco, California Earthquake · 28 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 37.7778, -122.1985. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Contra Costa County, CA 27 km (17 mi) NE earthquakes near Contra Costa County
Alameda County, CA 29 km (18 mi) ESE earthquakes near Alameda County
San Mateo County, CA 43 km (27 mi) SSW earthquakes near San Mateo County
Marin County, CA 57 km (35 mi) WNW earthquakes near Marin County
Solano County, CA 59 km (37 mi) NNE earthquakes near Solano County
San Francisco County, CA 74 km (46 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

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

  1. 1.6 1 km NW of Acalanes Ridge, California
  2. 2.0 1 km NE of Pacifica, California
  3. 1.8 1 km SSW of Loyola, California
  4. 1.5 1 km NNW of Piedmont, California
  5. 2.2 0 km NW of Piedmont, California
  6. 2.3 1 km NW of Piedmont, California
  7. 1.5 2 km NE of Pacifica, California
  8. 1.9 10 km N of East Foothills, California
  9. 1.6 3 km SSW of Alamo, California
  10. 1.6 1 km NE of Pacifica, California
  11. 2.9 2 km NE of Pacifica, California
  12. 1.7 2 km NE of Pacifica, California
  13. 1.6 2 km NE of Pacifica, California
  14. 1.7 1 km SSE of East Richmond Heights, California
  15. 1.7 10 km SW of Brentwood, California

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.