QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6md

Earthquake near Byron, CA

No earthquake was likely felt in Byron in the 24 hours to 7:14 pm PST (03:14 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 1.6 earthquake was recorded in Byron, CA, at 4:37 pm PST on 28 February 2024 (00:37 UTC), 7.7 km deep.

USGS: 0 km NE of Byron, CA

10 km (7 mi) SE of Brentwood, CA · 66 km (41 mi) NNE of San Jose, CA

4:37 pm PST, Feb 28, 2024 · · 7.7 km deep · released about 7.6 lb of TNT

Every earthquake near Byron Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 28 kmSan Joaquin County 33 kmAlameda County 35 kmSolano County 52 kmStanislaus County 65 kmSacramento County 69 kmSanta Clara County 72 kmSan Mateo County 82 kmYolo 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
4:37 pm PST on 28 February 2024 ()
Where
in Byron, CA · earthquakes near Byron
Magnitude
M 1.6 (md)
Depth
7.7 km below the surface
Felt
no reports yet
Nearest
Contra Costa County, 28 km WNW
Nearest mapped fault
Greenville fault, 16 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 987 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: Discovery Bay 5 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

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 5 earthquakes of M5 or more within 50 km:

  1. 5.8 The 1980 Livermore, California Earthquake · 12 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 · 50 km SSW of this epicentre
  4. 5.4 9 km NE of Livermore, California · 15 km SSW of this epicentre
  5. 5.1 11 km E of Blackhawk, California · 14 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 37.8693, -121.6342. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Contra Costa County, CA 28 km (18 mi) WNW earthquakes near Contra Costa County
San Joaquin County, CA 33 km (20 mi) ENE earthquakes near San Joaquin County
Alameda County, CA 35 km (22 mi) SW earthquakes near Alameda County
Solano County, CA 52 km (32 mi) NNW earthquakes near Solano County
Stanislaus County, CA 65 km (41 mi) ESE earthquakes near Stanislaus County
Sacramento County, CA 69 km (43 mi) NNE earthquakes near Sacramento County

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

Aftershocks so far

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

  1. 2.8 2 km SSE of Pacheco, CA
  2. 1.8 7 km SE of Fremont, CA
  3. 2.1 4 km E of Union City, CA
  4. 1.8 7 km SSE of Sunol, CA
  5. 1.7 2 km NNE of San Ramon, CA
  6. 2.9 11 km ENE of Milpitas, CA
  7. 1.8 4 km ENE of San Leandro, CA
  8. 2.5 7 km SSE of Sunol, CA
  9. 1.8 7 km SSE of Sunol, CA
  10. 1.9 2 km WNW of Diablo, CA
  11. 1.6 17 km SSE of Livermore, CA
  12. 2.3 9 km ESE of Fremont, CA
  13. 1.5 2 km SW of Alamo, CA
  14. 2.5 4 km SW of Antioch, CA
  15. 2.1 4 km SW of Antioch, 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.