Earthquake · reviewed by a seismologist
M 1.5md
Earthquake near Saratoga, CA
No earthquake was likely felt in Saratoga in the 24 hours to 9:22 pm PST (05:22 UTC). The last one was M 2.0, 7 km (4 mi) NW, at 9:23 am PST on 10 November 2026, estimated intensity II (weak) in town; 4 felt reports to USGS. Every earthquake near Saratoga
This page: a magnitude 1.5 earthquake was recorded 11 km (7 mi) west-southwest of Saratoga, CA, at 12:35 pm PDT on 10 October 2021 (19:35 UTC), 8.3 km deep.
USGS: 11km WSW of Saratoga, CA
30 km (19 mi) WSW of San Jose, CA · 13 km (8 mi) SW of Cupertino, CA
- When
- 12:35 pm PDT on 10 October 2021 ()
- Where
- 11 km (7 mi) west-southwest of Saratoga, CA · earthquakes near Saratoga
- Magnitude
- M 1.5 (md)
- Depth
- 8.3 km below the surface
- Felt
- no reports yet
- Nearest
- Santa Cruz County, 28 km SSE
- Nearest mapped fault
- Butano 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 1858 days ago
Earthquake alerts for Saratoga, CA
Get a notification in this browser when USGS records an earthquake near Saratoga, 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 6 km (4 mi) from the epicentre. In Saratoga, 11 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: Boulder Creek, Loyola, Monte Sereno, Cupertino, Brookdale, Los Gatos.
How big was it?
This earthquake released about 5.6 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 2,700,000× 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 5.6 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 4.1 on 2017-10-10 — about 7,400 times the energy of this one.
Before 2016, the USGS record lists 21 earthquakes of M5 or more within 50 km; the five largest:
- 6.9 The 1989 Loma Prieta, California Earthquake · 32 km SE of this epicentre
- 6.5 Near Morgan Hill, California · 47 km ESE of this epicentre
- 6.3 22 km S of Davenport, California · 48 km S of this epicentre
- 6.3 16 km SW of Davenport, California · 39 km SSW of this epicentre
- 6.2 Near San Jose, California · 31 km ENE 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 37.2360, -122.1445. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Santa Cruz County, CA | 28 km (17 mi) | SSE | earthquakes near Santa Cruz County |
| San Mateo County, CA | 28 km (18 mi) | NW | earthquakes near San Mateo County |
| Santa Clara County, CA | 40 km (25 mi) | E | earthquakes near Santa Clara County |
| Alameda County, CA | 50 km (31 mi) | NNE | earthquakes near Alameda County |
| Contra Costa County, CA | 78 km (48 mi) | NNE | earthquakes near Contra Costa County |
| San Francisco County, CA | 95 km (59 mi) | NW | earthquakes near San Francisco County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
38 earthquakes have been recorded within 50 km since this one.
- 1.6 2km E of Hayward, CA
- 1.6 2km ESE of Hayward, CA
- 3.6 4km ENE of Corralitos, CA
- 1.5 12km ESE of Alum Rock, CA
- 2.0 8km ENE of Milpitas, CA
- 1.7 22km W of Bonny Doon, CA
- 1.7 9km ENE of Alum Rock, CA
- 1.6 10km NNE of Alum Rock, CA
- 1.6 8km NNE of Milpitas, CA
- 2.7 5km SSW of Lexington Hills, CA
- 1.6 4km E of South San Francisco, CA
- 1.9 12km ESE of Alum Rock, CA
- 1.9 8km E of Alum Rock, CA
- 1.6 2km NE of Union City, CA
- 2.7 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.