Earthquake · reviewed by a seismologist
M 1.7md
Earthquake near Fremont, CA
No earthquake was likely felt in Fremont in the 24 hours to 11:35 pm PST (07:35 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 1.7 earthquake was recorded 6 km (4 mi) east of Fremont, CA, at 8:43 am PST on 20 November 2021 (16:43 UTC), 9.0 km deep.
USGS: 5km E of Fremont, CA
5 km (3 mi) NNE of Fremont, CA
- When
- 8:43 am PST on 20 November 2021 ()
- Where
- 6 km (4 mi) east of Fremont, CA · earthquakes near Fremont
- Magnitude
- M 1.7 (md)
- Depth
- 9.0 km below the surface
- Felt
- no reports yet
- Nearest
- Alameda County, 12 km N
- Nearest mapped fault
- Hayward fault, 2 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 1808 days ago
Earthquake alerts for Fremont, CA
Get a notification in this browser when USGS records an earthquake near Fremont, CA. No account or email needed.
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 9 km (6 mi) from the epicentre. In Fremont, 6 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: Fremont 6 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 12 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.
- Mineral, Virginia 2011 M 5.8 1,200,000× the energy of this one
- Magna, Utah 2020 M 5.7 870,000× the energy of this one
- Around the size people start to feel M 3.0 78× the energy of this one
- This earthquake M 1.7 about 12 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 12,000 times the energy of this one.
Before 2016, the USGS record lists 15 earthquakes of M5 or more within 50 km; the five largest:
- 6.2 Near San Jose, California · 29 km SSE of this epicentre
- 6.2 The 1984 Morgan Hill, California Earthquake · 33 km SE of this epicentre
- 6.1 Near San Jose, California · 39 km SSE of this epicentre
- 5.8 7 km NNW of Boulder Creek, California · 44 km SSW of this epicentre
- 5.8 The 1980 Livermore, California Earthquake · 36 km NNE 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 37.5402, -121.9218. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Alameda County, CA | 12 km (7 mi) | N | earthquakes near Alameda County |
| Santa Clara County, CA | 41 km (25 mi) | SSE | earthquakes near Santa Clara County |
| San Mateo County, CA | 42 km (26 mi) | WSW | earthquakes near San Mateo County |
| Contra Costa County, CA | 42 km (26 mi) | N | earthquakes near Contra Costa County |
| Santa Cruz County, CA | 59 km (37 mi) | S | earthquakes near Santa Cruz County |
| San Joaquin County, CA | 72 km (45 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
51 earthquakes have been recorded within 50 km since this one.
- 1.9 3km ESE of Pacheco, CA
- 1.9 8km E of Alum Rock, CA
- 1.7 2km SSW of Blackhawk, CA
- 1.6 2km NE of Union City, CA
- 1.8 3km ENE of San Leandro, CA
- 2.9 3km ENE of San Leandro, CA
- 1.6 2km ENE of Pacifica, CA
- 3.2 2km NNE of San Leandro, CA
- 1.6 5km WNW of Byron, CA
- 1.7 5km WNW of Byron, CA
- 1.9 5km SE of Brentwood, CA
- 2.7 16km E of Seven Trees, CA
- 3.1 2km ENE of San Leandro, CA
- 2.2 3km NNW of Diablo, CA
- 1.9 16km E of Seven Trees, 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.