Earthquake · reviewed by a seismologist
M 1.8md
Earthquake near Milpitas, CA
No earthquake was likely felt in Milpitas in the 24 hours to 8:06 am PST (16:06 UTC). The last one was M 1.6, 9 km (5 mi) NNE, at 5:49 am PDT on 4 October 2026, estimated intensity II (weak) in town. Every earthquake near Milpitas
This page: a magnitude 1.8 earthquake was recorded 10 km (6 mi) northeast of Milpitas, CA, at 4:31 pm PDT on 12 April 2023 (23:31 UTC), 5.8 km deep.
USGS: 10km NE of Milpitas, CA
21 km (13 mi) N of San Jose, CA · 9 km (6 mi) NE of Milpitas, CA
- When
- 4:31 pm PDT on 12 April 2023 ()
- Where
- 10 km (6 mi) northeast of Milpitas, CA · earthquakes near Milpitas
- Magnitude
- M 1.8 (md)
- Depth
- 5.8 km below the surface
- Felt
- no reports yet
- Nearest
- Alameda County, 19 km NNW
- Nearest mapped fault
- Calaveras fault, 4 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 1304 days ago
Earthquake alerts for Milpitas, CA
Get a notification in this browser when USGS records an earthquake near Milpitas, 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 12 km (7 mi) from the epicentre. In Milpitas, 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: Milpitas 10 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 14 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 1,100,000× the energy of this one
- Magna, Utah 2020 M 5.7 790,000× the energy of this one
- Around the size people start to feel M 3.0 70× the energy of this one
- This earthquake M 1.8 about 14 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 86,000 times the energy of this one.
Before 2016, the USGS record lists 17 earthquakes of M5 or more within 50 km; the five largest:
- 6.5 Near Morgan Hill, California · 45 km SSE of this epicentre
- 6.2 Near San Jose, California · 21 km S of this epicentre
- 6.2 The 1984 Morgan Hill, California Earthquake · 23 km SSE of this epicentre
- 6.1 Near San Jose, California · 32 km S of this epicentre
- 5.8 7 km NNW of Boulder Creek, California · 44 km SW 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 37.4887, -121.8180. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Alameda County, CA | 19 km (12 mi) | NNW | earthquakes near Alameda County |
| Santa Clara County, CA | 32 km (20 mi) | SSE | earthquakes near Santa Clara County |
| Contra Costa County, CA | 49 km (31 mi) | NNW | earthquakes near Contra Costa County |
| San Mateo County, CA | 50 km (31 mi) | W | earthquakes near San Mateo County |
| Santa Cruz County, CA | 56 km (35 mi) | SSW | earthquakes near Santa Cruz County |
| San Joaquin County, CA | 69 km (43 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.
- 2.1 5 km ESE of Oakland, CA
- 1.9 24 km NE of Alum Rock, CA
- 1.5 3km SSW of Cupertino, CA
- 1.8 9km SW of Brentwood, CA
- 2.0 7km SSE of Portola Valley, CA
- 2.0 2km SE of Portola Valley, CA
- 1.9 7km SSE of Portola Valley, CA
- 2.1 7km SSE of Portola Valley, CA
- 1.8 6km E of Milpitas, CA
- 1.6 10km NE of Morgan Hill, CA
- 1.9 13km NNE of Morgan Hill, CA
- 1.7 10km NNE of Alum Rock, CA
- 1.9 5km NNW of Day Valley, CA
- 2.2 4km E of Walnut Creek, CA
- 1.7 5km E of Walnut Creek, 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.