QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7md

Earthquake near Pleasanton, CA

Yes. A magnitude 1.7 earthquake was recorded 5 km (3 mi) SSE of Pleasanton, CA, at 11:55 pm PDT on 20 May 2016 (06:55 UTC), 14 km deep.

This was on 20 May 2016. The latest near Pleasanton: M 2.5 on 19 September 2026.

USGS: 3 km NE of Sunol, California

6 km (4 mi) SSE of Pleasanton, CA · 36 km (22 mi) N of San Jose, CA

11:55 pm PDT, May 20, 2016 · · 14 km deep · released about 12 lb of TNT

10 km30 km60 km120 km N Alameda County 6 kmContra Costa County 34 kmSanta Clara County 47 kmSan Mateo County 51 kmSan Joaquin County 62 kmSanta Cruz County 69 kmSolano County 72 kmStanislaus County 76 kmMarin County 92 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
11:55 pm PDT on 20 May 2016 ()
Where
5 km (3 mi) SSE of Pleasanton, CA · earthquakes near Pleasanton
Magnitude
M 1.7 (md)
Depth
14 km below the surface
Felt
no reports yet
Nearest
Alameda County, 6 km WNW
Nearest mapped fault
Calaveras fault, 3 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 3532 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 Pleasanton, 5 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: Livermore, Dublin, Fremont, Union City, Fairview, Newark.

How big was it?

This earthquake released about 12 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,200,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 870,000× the energy of this one
  3. Around the size people start to feel M 3.0 78× the energy of this one
  4. This earthquake M 1.7 about 12 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 10 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.2 Near San Jose, California · 36 km S of this epicentre
  2. 6.2 The 1984 Morgan Hill, California Earthquake · 38 km SSE of this epicentre
  3. 6.1 Near San Jose, California · 47 km S of this epicentre
  4. 5.8 The 1980 Livermore, California Earthquake · 26 km NNE of this epicentre
  5. 5.7 15 km NE of East Foothills, California · 22 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 37.6190, -121.8570. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Alameda County, CA 6 km (4 mi) WNW earthquakes near Alameda County
Contra Costa County, CA 34 km (21 mi) NNW earthquakes near Contra Costa County
Santa Clara County, CA 47 km (29 mi) SSE earthquakes near Santa Clara County
San Mateo County, CA 51 km (32 mi) WSW earthquakes near San Mateo County
San Joaquin County, CA 62 km (39 mi) NE earthquakes near San Joaquin County
Santa Cruz County, CA 69 km (43 mi) S earthquakes near Santa Cruz County

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

Aftershocks so far

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

  1. 2.1 1 km E of Berkeley, California
  2. 1.6 10 km WSW of Brentwood, California
  3. 1.8 14 km E of Seven Trees, California
  4. 2.2 5 km ENE of East Foothills, California
  5. 1.8 3 km SE of Hayward, California
  6. 1.9 3 km N of Diablo, California
  7. 2.1 6 km NE of East Foothills, California
  8. 1.5 7 km NW of Livermore, California
  9. 2.1 8 km SSE of Sunol, California
  10. 1.5 1 km S of Alamo, California
  11. 1.6 2 km WNW of Los Altos Hills, California
  12. 2.0 2 km WSW of Blackhawk, California
  13. 1.8 3 km S of Loyola, California
  14. 1.7 1 km NNW of Ashland, California
  15. 1.9 4 km SW of Dublin, 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.