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 1:43 pm PST (21:43 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 18 km (11 mi) east of San Jose, CA, at 2:21 am PDT on 9 April 2023 (09:21 UTC), 8.0 km deep.
USGS: 12km ESE of Alum Rock, CA
11 km (7 mi) ENE of San Jose, CA
- When
- 2:21 am PDT on 9 April 2023 ()
- Where
- 18 km (11 mi) east of San Jose, CA · earthquakes near San Jose
- Magnitude
- M 1.6 (md)
- Depth
- 8.0 km below the surface
- Felt
- no reports yet
- Nearest
- Santa Clara County, 13 km S
- Nearest mapped fault
- Calaveras 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 1310 days ago
Earthquake alerts for San Jose, 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 San Jose, 18 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.
Earthquakes near other towns within 30 km: East Foothills, Milpitas, Santa Clara, Campbell, Morgan Hill, Los Gatos.
How big was it?
This earthquake released about 6.8 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.
- Mineral, Virginia 2011 M 5.8 2,200,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,600,000× the energy of this one
- Around the size people start to feel M 3.0 140× the energy of this one
- This earthquake M 1.6 about 6.8 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 170,000 times the energy of this one.
Before 2016, the USGS record lists 23 earthquakes of M5 or more within 50 km; the five largest:
- 6.9 The 1989 Loma Prieta, California Earthquake · 37 km SSW of this epicentre
- 6.5 Near Morgan Hill, California · 26 km SSE of this epicentre
- 6.2 Near San Jose, California · 10 km WSW of this epicentre
- 6.2 The 1984 Morgan Hill, California Earthquake · 3 km SSE of this epicentre
- 6.1 Near San Jose, California · 18 km SSW 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 37.3373, -121.6970. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Santa Clara County, CA | 13 km (8 mi) | S | earthquakes near Santa Clara County |
| Alameda County, CA | 39 km (24 mi) | NNW | earthquakes near Alameda County |
| Santa Cruz County, CA | 45 km (28 mi) | SW | earthquakes near Santa Cruz County |
| San Mateo County, CA | 60 km (37 mi) | W | earthquakes near San Mateo County |
| Stanislaus County, CA | 66 km (41 mi) | ENE | earthquakes near Stanislaus County |
| Contra Costa County, CA | 69 km (43 mi) | NNW | earthquakes near Contra Costa County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
48 earthquakes have been recorded within 50 km since this one.
- 1.9 7km SSE of Portola Valley, CA
- 2.1 7km SSE of Portola Valley, CA
- 1.8 6km E of Milpitas, CA
- 2.4 8km NE of Gilroy, CA
- 1.6 10km NE of Morgan Hill, CA
- 1.9 13km NNE of Morgan Hill, CA
- 1.6 13km ESE of Gilroy, CA
- 2.6 7km WSW of Gilroy, CA
- 1.9 11km NNW of Hollister, CA
- 2.6 6km SSW of Gilroy, CA
- 1.7 10km NNE of Alum Rock, CA
- 1.9 5km NNW of Day Valley, CA
- 1.7 4km SW of Felton, CA
- 1.6 13km ESE of Gilroy, CA
- 1.7 12km ESE of Gilroy, 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.