Earthquake · reviewed by a seismologist
M 1.7md
Earthquake near Fremont, CA
No earthquake was likely felt in Fremont in the 24 hours to 10:54 pm PST (06:54 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 in Fremont, CA, at 3:50 am PDT on 9 April 2020 (10:50 UTC), 4.6 km deep. 4 people have reported feeling it to USGS.
USGS: 1km E of Fremont, CA
6 km (4 mi) NNW of Fremont, CA
- When
- 3:50 am PDT on 9 April 2020 ()
- Where
- in Fremont, CA · earthquakes near Fremont
- Magnitude
- M 1.7 (md)
- Depth
- 4.6 km below the surface
- Felt
- 4 reports · strongest reported intensity III
- Nearest
- Alameda County, 12 km NNE
- Nearest mapped fault
- Hayward fault, under 1 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 2406 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 11 km (7 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: Fremont in town, intensity II · Newark 7 km, intensity II · Union City 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 10 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 1,500,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,000,000× the energy of this one
- Around the size people start to feel M 3.0 92× the energy of this one
- This earthquake M 1.7 about 10 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 14,000 times the energy of this one.
Before 2016, the USGS record lists 16 earthquakes of M5 or more within 50 km; the five largest:
- 6.2 Near San Jose, California · 31 km SSE of this epicentre
- 6.2 The 1984 Morgan Hill, California Earthquake · 36 km SE of this epicentre
- 6.1 Near San Jose, California · 41 km SSE of this epicentre
- 5.8 7 km NNW of Boulder Creek, California · 43 km SSW of this epicentre
- 5.8 The 1980 Livermore, California Earthquake · 37 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 37.5445, -121.9672. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Alameda County, CA | 12 km (8 mi) | NNE | earthquakes near Alameda County |
| San Mateo County, CA | 38 km (24 mi) | WSW | earthquakes near San Mateo County |
| Contra Costa County, CA | 42 km (26 mi) | N | earthquakes near Contra Costa County |
| Santa Clara County, CA | 43 km (27 mi) | SE | earthquakes near Santa Clara County |
| Santa Cruz County, CA | 59 km (37 mi) | S | earthquakes near Santa Cruz County |
| San Joaquin County, CA | 75 km (47 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
58 earthquakes have been recorded within 50 km since this one.
- 1.6 14km SE of Livermore, CA
- 1.9 2km NNE of Alameda, CA
- 1.9 1km NW of Pleasant Hill, CA
- 2.7 3km W of Portola Valley, CA
- 1.7 3km W of Portola Valley, CA
- 1.8 10km NE of Blackhawk, CA
- 1.5 9km N of Boulder Creek, CA
- 1.7 3km W of Portola Valley, CA
- 1.8 3km W of Portola Valley, CA
- 1.8 2km SW of Los Altos Hills, CA
- 3.4 8km NE of Alum Rock, CA
- 1.8 4km E of Livermore, CA
- 2.1 8km ENE of Alum Rock, CA
- 1.6 15km E of Seven Trees, CA
- 1.6 1km SSE of San Ramon, 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.