QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6md

Earthquake near Pittsburg, CA

No earthquake was likely felt in Pittsburg in the 24 hours to 3:52 am PST (11:52 UTC). The last one was M 2.5, 15 km (9 mi) WSW, at 1:23 am PST on 2 November 2026, estimated intensity II (weak) in town; 39 felt reports to USGS. Every earthquake near Pittsburg

This page: a magnitude 1.6 earthquake was recorded 12 km (8 mi) north-northeast of Pittsburg, CA, at 12:36 pm PDT on 4 April 2025 (19:36 UTC), 26 km deep.

USGS: 12 km NE of Pittsburg, CA

14 km (9 mi) NNE of Pittsburg, CA · 65 km (40 mi) NE of San Francisco, CA

12:36 pm PDT, Apr 4, 2025 · · 26 km deep · released about 7.1 lb of TNT

10 km30 km60 km120 km N Solano County 18 kmContra Costa County 26 kmSan Joaquin County 53 kmAlameda County 54 kmSacramento County 55 kmNapa County 60 kmYolo County 62 kmMarin County 81 kmSan Mateo County 93 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
12:36 pm PDT on 4 April 2025 ()
Where
12 km (8 mi) north-northeast of Pittsburg, CA · earthquakes near Pittsburg
Magnitude
M 1.6 (md)
Depth
26 km below the surface
Felt
no reports yet
Nearest
Solano County, 18 km NNW
Nearest mapped fault
Great Valley thrust fault system, 21 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 531 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 Pittsburg, 12 km away, the estimate is intensity I (not felt). 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: Rio Vista, Antioch, Bay Point, Oakley, Bethel Island, Suisun.

How big was it?

This earthquake released about 7.1 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 2,100,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,500,000× 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 7.1 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 21,000 times the energy of this one.

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

  1. 6.0 The 2014 South Napa, California Earthquake · 43 km WNW of this epicentre
  2. 5.8 The 1980 Livermore, California Earthquake · 32 km S of this epicentre
  3. 5.4 South of Elmira, California · 20 km NNW of this epicentre
  4. 5.4 9 km NE of Livermore, California · 43 km SSE of this epicentre
  5. 5.1 11 km E of Blackhawk, California · 36 km S 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 38.1278, -121.8290. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Solano County, CA 18 km (11 mi) NNW earthquakes near Solano County
Contra Costa County, CA 26 km (16 mi) SSW earthquakes near Contra Costa County
San Joaquin County, CA 53 km (33 mi) ESE earthquakes near San Joaquin County
Alameda County, CA 54 km (34 mi) S earthquakes near Alameda County
Sacramento County, CA 55 km (34 mi) NE earthquakes near Sacramento County
Napa County, CA 60 km (38 mi) NW earthquakes near Napa County

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

Aftershocks so far

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

  1. 2.5 2 km NW of Walnut Creek, CA
  2. 2.9 5 km ENE of Fairview, CA
  3. 1.9 5 km WNW of Dublin, CA
  4. 1.7 3 km NNE of Dublin, CA
  5. 1.8 7 km E of Vallejo, CA
  6. 1.5 3 km SW of Clayton, CA
  7. 1.9 3 km ESE of Walnut Creek, CA
  8. 1.9 6 km SE of Moraga, CA
  9. 2.2 13 km SE of Suisun City, CA
  10. 2.7 6 km ESE of Clayton, CA
  11. 1.6 5 km E of Vallejo, CA
  12. 2.0 3 km WSW of Country Club, CA
  13. 2.1 4 km SE of Rodeo, CA
  14. 1.6 3 km SE of Rodeo, CA
  15. 3.2 2 km NW of Pinole, 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.