QuakeIndex

Earthquake · reviewed by a seismologist

M 2.5md

Earthquake near Rio Vista, CA

No earthquake was likely felt in Rio Vista in the 24 hours to 4:49 pm PST (00:49 UTC). The last one was M 3.1, 35 km (22 mi) SSW, at 12:25 am PDT on 12 September 2026, estimated intensity II (weak) in town; 257 felt reports to USGS. Every earthquake near Rio Vista

This page: a magnitude 2.5 earthquake was recorded 4 km (3 mi) south-southeast of Rio Vista, CA, at 8:49 am PDT on 23 October 2023 (15:49 UTC), less than 1 km deep. 1 person has reported feeling it to USGS.

USGS: 4 km SSE of Rio Vista, CA

76 km (47 mi) ENE of San Francisco, CA · 20 km (12 mi) NNE of Antioch, CA

8:49 am PDT, Oct 23, 2023 · · 0.0 km deep · released about 160 lb of TNT

Every earthquake near Rio Vista Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Solano County 28 kmContra Costa County 34 kmSan Joaquin County 41 kmSacramento County 46 kmAlameda County 58 kmYolo County 64 kmNapa County 71 kmStanislaus County 86 kmMarin County 95 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
8:49 am PDT on 23 October 2023 ()
Where
4 km (3 mi) south-southeast of Rio Vista, CA · earthquakes near Rio Vista
Magnitude
M 2.5 (md)
Depth
0.0 km below the surface
Felt
1 report · strongest reported intensity I
Nearest
Solano County, 28 km WNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1043 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 22 km (14 mi) from the epicentre. In Rio Vista, 4 km away, the estimate is intensity III (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: Rio Vista 4 km, intensity III · Oakley 15 km, intensity II · Antioch 18 km, intensity II · Pittsburg 22 km, intensity II · Brentwood 22 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 160 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 92,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 65,000× the energy of this one
  3. Around the size people start to feel M 3.0 5.8× the energy of this one
  4. This earthquake M 2.5 about 160 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 900 times the energy of this one.

Before 2016, the USGS record lists 4 earthquakes of M5 or more within 50 km:

  1. 5.8 The 1980 Livermore, California Earthquake · 33 km SSW of this epicentre
  2. 5.4 South of Elmira, California · 28 km NW of this epicentre
  3. 5.4 9 km NE of Livermore, California · 42 km S of this epicentre
  4. 5.1 11 km E of Blackhawk, California · 37 km SSW 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 38.1290, -121.6703. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Solano County, CA 28 km (17 mi) WNW earthquakes near Solano County
Contra Costa County, CA 34 km (21 mi) SW earthquakes near Contra Costa County
San Joaquin County, CA 41 km (25 mi) ESE earthquakes near San Joaquin County
Sacramento County, CA 46 km (28 mi) NE earthquakes near Sacramento County
Alameda County, CA 58 km (36 mi) SSW earthquakes near Alameda County
Yolo County, CA 64 km (40 mi) NNW earthquakes near Yolo County

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

Aftershocks so far

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

  1. 1.7 5 km E of Vallejo, CA
  2. 1.6 2 km N of Livermore, CA
  3. 1.6 6 km ENE of Vallejo, CA
  4. 1.8 10 km ENE of Blackhawk, CA
  5. 1.8 10 km SSW of Brentwood, CA
  6. 1.5 6 km E of Walnut Creek, CA
  7. 1.7 1 km W of Pacheco, CA
  8. 2.0 10 km ESE of Clayton, CA
  9. 1.9 11 km E of Blackhawk, CA
  10. 2.6 3 km SE of Pleasant Hill, CA
  11. 1.9 2 km NW of Alamo, CA
  12. 1.8 2 km SE of Pacheco, CA
  13. 1.5 5 km E of Vallejo, CA
  14. 2.3 4 km ENE of Walnut Creek, CA
  15. 1.6 1 km SSW of Alamo, 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.