Earthquake · reviewed by a seismologist
M 1.5md
Earthquake near Fremont, CA
No earthquake was likely felt in Fremont in the 24 hours to 3:29 pm PST (23:29 UTC). The last one was M 3.5, 49 km (31 mi) ESE, at 7:21 am PDT on 27 September 2026, estimated intensity II (weak) in town; 8 felt reports to USGS. Every earthquake near Fremont
This page: a magnitude 1.5 earthquake was recorded 10 km (6 mi) north-northeast of Fremont, CA, at 4:34 am PST on 4 February 2023 (12:34 UTC), 7.6 km deep.
USGS: 6km WNW of Sunol, CA
7 km (4 mi) WSW of Pleasanton, CA · 39 km (24 mi) NNW of San Jose, CA
- When
- 4:34 am PST on 4 February 2023 ()
- Where
- 10 km (6 mi) north-northeast of Fremont, CA · earthquakes near Fremont
- Magnitude
- M 1.5 (md)
- Depth
- 7.6 km below the surface
- Felt
- no reports yet
- Nearest
- Alameda County, 3 km ENE
- 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 1372 days ago
Earthquake alerts for Fremont, CA
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Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
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 7 km (4 mi) from the epicentre. In Fremont, 10 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.
Likely felt in: Pleasanton 7 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 5.7 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 2,600,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,900,000× the energy of this one
- Around the size people start to feel M 3.0 170× the energy of this one
- This earthquake M 1.5 about 5.7 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 200,000 times the energy of this one.
Before 2016, the USGS record lists 11 earthquakes of M5 or more within 50 km; the five largest:
- 6.2 Near San Jose, California · 39 km SSE of this epicentre
- 6.2 The 1984 Morgan Hill, California Earthquake · 43 km SSE of this epicentre
- 6.1 Near San Jose, California · 50 km SSE of this epicentre
- 5.8 The 1980 Livermore, California Earthquake · 28 km NE of this epicentre
- 5.7 15 km NE of East Foothills, California · 29 km SE 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 37.6327, -121.9467. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Alameda County, CA | 3 km (2 mi) | ENE | earthquakes near Alameda County |
| Contra Costa County, CA | 32 km (20 mi) | N | earthquakes near Contra Costa County |
| San Mateo County, CA | 45 km (28 mi) | WSW | earthquakes near San Mateo County |
| Santa Clara County, CA | 51 km (32 mi) | SSE | earthquakes near Santa Clara County |
| San Joaquin County, CA | 68 km (42 mi) | ENE | earthquakes near San Joaquin County |
| Santa Cruz County, CA | 69 km (43 mi) | S | earthquakes near Santa Cruz County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
54 earthquakes have been recorded within 50 km since this one.
- 2.4 6km SSW of Antioch, CA
- 2.3 6km SSW of Antioch, CA
- 2.0 8km NE of Alum Rock, CA
- 2.0 9km W of Brentwood, CA
- 1.7 9km ESE of Clayton, CA
- 1.7 9km ESE of Clayton, CA
- 3.6 9km ESE of Clayton, CA
- 1.8 5km S of Concord, CA
- 1.7 9km E of Alum Rock, CA
- 1.8 10km NE of Milpitas, CA
- 2.5 12km ESE of Alum Rock, CA
- 1.6 12km ESE of Alum Rock, CA
- 1.7 12km ESE of Alum Rock, CA
- 2.4 12km ESE of Alum Rock, CA
- 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
- The official USGS event page — the source of record for every value above
- Did you feel it? Report it to USGS — reports go to USGS, not to us
- ShakeMap for this event, when USGS has produced one
QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.