QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7md

Earthquake near Byron, CA

No earthquake was likely felt in Byron in the 24 hours to 9:56 pm PST (05:56 UTC). The last one was M 3.5, 53 km (33 mi) SSE, at 7:21 am PDT on 27 September 2026, estimated intensity II (weak) in town; 8 felt reports to USGS. Every earthquake near Byron

This page: a magnitude 1.7 earthquake was recorded 3 km (2 mi) west of Byron, CA, at 1:57 pm PDT on 25 July 2017 (20:57 UTC), 14 km deep.

USGS: 3 km W of Byron, California

8 km (5 mi) SSE of Brentwood, CA · 65 km (40 mi) N of San Jose, CA

1:57 pm PDT, Jul 25, 2017 · · 14 km deep · released about 9.3 lb of TNT

Every earthquake near Byron Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 25 kmAlameda County 32 kmSan Joaquin County 36 kmSolano County 50 kmStanislaus County 68 kmSacramento County 71 kmSanta Clara County 72 kmSan Mateo County 80 kmNapa County 91 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
1:57 pm PDT on 25 July 2017 ()
Where
3 km (2 mi) west of Byron, CA · earthquakes near Byron
Magnitude
M 1.7 (md)
Depth
14 km below the surface
Felt
no reports yet
Nearest
Contra Costa County, 25 km WNW
Nearest mapped fault
Greenville fault, 13 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 3396 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 Byron, 3 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: Brentwood, Discovery Bay, Knightsen, Oakley, Mountain House, Bethel Island.

How big was it?

This earthquake released about 9.3 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 1,600,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,100,000× the energy of this one
  3. Around the size people start to feel M 3.0 100× the energy of this one
  4. This earthquake M 1.7 about 9.3 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 5 earthquakes of M5 or more within 50 km:

  1. 5.8 The 1980 Livermore, California Earthquake · 9 km WSW of this epicentre
  2. 5.7 15 km NE of East Foothills, California · 44 km S of this epicentre
  3. 5.5 6 km NNE of East Foothills, California · 49 km S of this epicentre
  4. 5.4 9 km NE of Livermore, California · 14 km SSW of this epicentre
  5. 5.1 11 km E of Blackhawk, California · 11 km SW 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 37.8705, -121.6748. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Contra Costa County, CA 25 km (15 mi) WNW earthquakes near Contra Costa County
Alameda County, CA 32 km (20 mi) SW earthquakes near Alameda County
San Joaquin County, CA 36 km (22 mi) ENE earthquakes near San Joaquin County
Solano County, CA 50 km (31 mi) NNW earthquakes near Solano County
Stanislaus County, CA 68 km (42 mi) ESE earthquakes near Stanislaus County
Sacramento County, CA 71 km (44 mi) NNE earthquakes near Sacramento County

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

Aftershocks so far

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

  1. 1.7 5km NNE of San Leandro, CA
  2. 2.4 1km E of Pacheco, CA
  3. 2.1 3 km SSE of Rio Vista, California
  4. 2.0 10 km ENE of Milpitas, California
  5. 1.6 2 km NNW of Pleasant Hill, California
  6. 2.7 6km SE of Rio Vista, CA
  7. 2.0 3km E of Rio Vista, CA
  8. 2.3 1 km E of Pacheco, California
  9. 2.3 2 km SSE of Dublin, California
  10. 2.6 15 km SSE of Livermore, California
  11. 2.9 15 km SSE of Livermore, California
  12. 2.3 15 km SSE of Livermore, California
  13. 1.7 11 km SSE of Livermore, California
  14. 1.6 2 km W of Danville, California
  15. 2.0 2 km WSW of Clyde, 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.