QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6md

Earthquake near San Ramon, CA

No earthquake was likely felt in San Ramon in the 24 hours to 5:48 am PST (13:48 UTC). The last one was M 2.1, 6 km (4 mi) NNE, at 7:18 am PDT on 31 October 2026, estimated intensity II (weak) in town; 1 felt report to USGS. Every earthquake near San Ramon

This page: a magnitude 1.6 earthquake was recorded 4 km (3 mi) southeast of San Ramon, CA, at 6:09 pm PST on 15 December 2025 (02:09 UTC), 7.6 km deep.

USGS: 4 km SE of San Ramon, CA

in San Ramon, CA · 42 km (26 mi) E of San Francisco, CA

6:09 pm PST, Dec 15, 2025 · · 7.6 km deep · released about 7.8 lb of TNT

Every earthquake near San Ramon Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Alameda County 13 kmContra Costa County 18 kmSan Mateo County 54 kmSolano County 57 kmSan Joaquin County 62 kmSanta Clara County 64 kmMarin County 78 kmSanta Cruz County 83 kmStanislaus County 85 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
6:09 pm PST on 15 December 2025 ()
Where
4 km (3 mi) southeast of San Ramon, CA · earthquakes near San Ramon
Magnitude
M 1.6 (md)
Depth
7.6 km below the surface
Felt
no reports yet
Nearest
Alameda County, 13 km S
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 320 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 San Ramon, 4 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: San Ramon 4 km, intensity II · Dublin 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 7.8 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 1,900,000× 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 3.0 120× the energy of this one
  4. This earthquake M 1.6 about 7.8 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 19,000 times the energy of this one.

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 · 38 km SE of this epicentre
  3. 5.5 6 km NNE of East Foothills, California · 39 km SSE of this epicentre
  4. 5.4 9 km NE of Livermore, California · 21 km E of this epicentre
  5. 5.3 The 1957 San Francisco, California Earthquake · 49 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 37.7580, -121.9400. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Alameda County, CA 13 km (8 mi) S earthquakes near Alameda County
Contra Costa County, CA 18 km (11 mi) N earthquakes near Contra Costa County
San Mateo County, CA 54 km (33 mi) SW earthquakes near San Mateo County
Solano County, CA 57 km (35 mi) N earthquakes near Solano County
San Joaquin County, CA 62 km (38 mi) ENE earthquakes near San Joaquin County
Santa Clara County, CA 64 km (40 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

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

  1. 2.0 4 km SSE of San Ramon, CA
  2. 2.6 4 km SE of San Ramon, CA
  3. 2.0 5 km SE of San Ramon, CA
  4. 2.2 5 km SE of San Ramon, CA
  5. 2.2 5 km ESE of San Ramon, CA
  6. 1.6 4 km SE of San Ramon, CA
  7. 2.2 5 km SE of San Ramon, CA
  8. 1.6 21 km SE of Livermore, CA
  9. 2.3 4 km SE of San Ramon, CA
  10. 2.4 4 km SE of San Ramon, CA
  11. 1.9 5 km SE of San Ramon, CA
  12. 1.5 5 km SE of San Ramon, CA
  13. 2.0 4 km SE of San Ramon, CA
  14. 1.9 5 km SE of San Ramon, CA
  15. 2.0 4 km ESE of San Ramon, 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.