QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6md

Earthquake near San Ramon, CA

Yes. A magnitude 1.6 earthquake was recorded in San Ramon, CA, at 2:12 pm PDT on 31 July 2016 (21:12 UTC), 8.0 km deep.

This was on 31 July 2016. The latest near San Ramon: M 3.0 on 14 September 2026.

USGS: 1 km NE of San Ramon, California

in San Ramon, CA · 40 km (25 mi) E of San Francisco, CA

2:12 pm PDT, Jul 31, 2016 · · 8.0 km deep · released about 7.6 lb of TNT

10 km30 km60 km120 km N Contra Costa County 14 kmAlameda County 16 kmSolano County 53 kmSan Mateo County 55 kmSan Joaquin County 63 kmSanta Clara County 68 kmMarin County 75 kmNapa County 86 kmSanta Cruz County 87 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
2:12 pm PDT on 31 July 2016 ()
Where
in San Ramon, CA · earthquakes near San Ramon
Magnitude
M 1.6 (md)
Depth
8.0 km below the surface
Felt
no reports yet
Nearest
Contra Costa County, 14 km N
Nearest mapped fault
Pleasanton fault, under 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 3532 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. 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 Ramon in town, intensity II · Danville 5 km, intensity II · Diablo 5 km, intensity II · Blackhawk 6 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 7.6 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 2,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,400,000× the energy of this one
  3. Around the size people start to feel M 3.0 130× the energy of this one
  4. This earthquake M 1.6 about 7.6 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 7 earthquakes of M5 or more within 50 km; the five largest:

  1. 5.8 The 1980 Livermore, California Earthquake · 18 km ENE of this epicentre
  2. 5.7 15 km NE of East Foothills, California · 42 km SE of this epicentre
  3. 5.5 6 km NNE of East Foothills, California · 43 km SSE of this epicentre
  4. 5.4 9 km NE of Livermore, California · 23 km E of this epicentre
  5. 5.3 The 1957 San Francisco, California Earthquake · 48 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 37.7895, -121.9642. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Contra Costa County, CA 14 km (9 mi) N earthquakes near Contra Costa County
Alameda County, CA 16 km (10 mi) SSE earthquakes near Alameda County
Solano County, CA 53 km (33 mi) N earthquakes near Solano County
San Mateo County, CA 55 km (34 mi) SW earthquakes near San Mateo County
San Joaquin County, CA 63 km (39 mi) ENE earthquakes near San Joaquin County
Santa Clara County, CA 68 km (42 mi) SSE earthquakes near Santa Clara County

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

Aftershocks so far

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

  1. 1.8 3 km W of Orinda, California
  2. 2.0 3 km W of Orinda, California
  3. 1.8 2 km NE of Pacifica, California
  4. 1.8 5 km ENE of Chinatown, California
  5. 1.5 2 km N of Piedmont, California
  6. 2.1 6 km S of Sunol, California
  7. 2.2 7 km E of Blackhawk, California
  8. 1.6 1 km ESE of Pacheco, California
  9. 1.5 5 km E of Alameda, California
  10. 1.5 5 km ENE of Chinatown, California
  11. 1.9 2 km ENE of Diablo, California
  12. 2.4 8 km NNE of East Foothills, California
  13. 1.6 5 km ESE of Piedmont, California
  14. 1.6 1 km NW of Ashland, California
  15. 1.5 10 km N of Livermore, 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.