QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6md

Earthquake near San Jose, CA

No earthquake was likely felt in San Jose in the 24 hours to 6:07 pm PST (02:07 UTC). The last one was M 2.6, 19 km (12 mi) E, at 12:38 pm PDT on 27 October 2026, estimated intensity II (weak) in town; 8 felt reports to USGS. Every earthquake near San Jose

This page: a magnitude 1.6 earthquake was recorded 25 km (15 mi) north-northeast of San Jose, CA, at 2:50 pm PST on 23 January 2023 (22:50 UTC), 14 km deep.

USGS: 8km SE of Sunol, CA

29 km (18 mi) N of San Jose, CA · 12 km (7 mi) ENE of Fremont, CA

2:50 pm PST, Jan 23, 2023 · · 14 km deep · released about 8.1 lb of TNT

10 km30 km60 km120 km N Alameda County 13 kmSanta Clara County 39 kmContra Costa County 42 kmSan Mateo County 51 kmSanta Cruz County 62 kmSan Joaquin County 65 kmStanislaus County 73 kmSolano County 80 kmMarin County 98 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
2:50 pm PST on 23 January 2023 ()
Where
25 km (15 mi) north-northeast of San Jose, CA · earthquakes near San Jose
Magnitude
M 1.6 (md)
Depth
14 km below the surface
Felt
no reports yet
Nearest
Alameda County, 13 km NW
Nearest mapped fault
Calaveras fault, 3 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 1387 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 San Jose, 25 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: Pleasanton, Fremont, Livermore, Milpitas, Union City, Newark.

How big was it?

This earthquake released about 8.1 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 1,900,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,300,000× 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 8.1 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 5.1 on 2022-10-25 — about 140,000 times the energy of this one.

Before 2016, the USGS record lists 15 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.2 Near San Jose, California · 28 km S of this epicentre
  2. 6.2 The 1984 Morgan Hill, California Earthquake · 30 km SSE of this epicentre
  3. 6.1 Near San Jose, California · 39 km S of this epicentre
  4. 5.8 7 km NNW of Boulder Creek, California · 49 km SW of this epicentre
  5. 5.8 The 1980 Livermore, California Earthquake · 32 km N 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 37.5533, -121.8262. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Alameda County, CA 13 km (8 mi) NW earthquakes near Alameda County
Santa Clara County, CA 39 km (24 mi) SSE earthquakes near Santa Clara County
Contra Costa County, CA 42 km (26 mi) NNW earthquakes near Contra Costa County
San Mateo County, CA 51 km (31 mi) WSW earthquakes near San Mateo County
Santa Cruz County, CA 62 km (39 mi) SSW earthquakes near Santa Cruz County
San Joaquin County, CA 65 km (40 mi) NE earthquakes near San Joaquin County

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

Aftershocks so far

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

  1. 2.4 6km SSW of Antioch, CA
  2. 2.3 6km SSW of Antioch, CA
  3. 2.0 8km NE of Alum Rock, CA
  4. 2.0 9km W of Brentwood, CA
  5. 1.7 9km ESE of Clayton, CA
  6. 1.7 9km ESE of Clayton, CA
  7. 3.6 9km ESE of Clayton, CA
  8. 1.8 5km S of Concord, CA
  9. 1.7 9km E of Alum Rock, CA
  10. 1.8 10km NE of Milpitas, CA
  11. 2.5 12km ESE of Alum Rock, CA
  12. 1.6 12km ESE of Alum Rock, CA
  13. 1.7 12km ESE of Alum Rock, CA
  14. 2.4 12km ESE of Alum Rock, CA
  15. 2.2 15km N of Morgan Hill, 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.