QuakeIndex

Earthquake · reviewed by a seismologist

M 3.1ml

Earthquake near Sunnyvale, CA

No earthquake was likely felt in Sunnyvale in the 24 hours to 12:43 pm PST (20:43 UTC). The last one was M 2.0, 8 km (5 mi) SSW, at 9:23 am PST on 10 November 2026, estimated intensity II (weak) in town; 4 felt reports to USGS. Every earthquake near Sunnyvale

This page: a magnitude 3.1 earthquake was recorded 44 km (28 mi) west-southwest of Sunnyvale, CA, at 9:28 pm PDT on 30 July 2025 (04:28 UTC), 14 km deep. 238 people have reported feeling it to USGS.

USGS: 31 km SW of Portola Valley, CA

60 km (37 mi) WSW of San Jose, CA · 38 km (24 mi) SW of Palo Alto, CA

9:28 pm PDT, Jul 30, 2025 · · 14 km deep · released about 1,400 lb of TNT

Every earthquake near Sunnyvale Felt it? Tell USGS Check my area
10 km30 km60 km120 km N San Mateo County 28 kmSanta Cruz County 45 kmSanta Clara County 70 kmAlameda County 72 kmSan Francisco County 79 kmContra Costa County 95 kmMarin County 100 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
9:28 pm PDT on 30 July 2025 ()
Where
44 km (28 mi) west-southwest of Sunnyvale, CA · earthquakes near Sunnyvale
Magnitude
M 3.1 (ml)
Depth
14 km below the surface
Felt
238 reports · strongest reported intensity IV
Nearest
San Mateo County, 28 km NNE
Nearest mapped fault
San Gregorio fault, 10 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 392 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 40 km (25 mi) from the epicentre. In Sunnyvale, 44 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: Boulder Creek 32 km, intensity II · Half Moon Bay 32 km, intensity II · Los Altos 40 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 1,400 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.1 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 240,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 11,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 7,700× the energy of this one
  4. This earthquake M 3.1 about 1,400 lb of TNT
  5. Around the size people start to feel M 3.0 this one released 1.5× more

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

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

Before 2016, the USGS record lists 9 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.3 22 km S of Davenport, California · 47 km SSE of this epicentre
  2. 6.3 16 km SW of Davenport, California · 30 km SSE of this epicentre
  3. 5.8 7 km NNW of Boulder Creek, California · 29 km E of this epicentre
  4. 5.5 Santa Cruz Mountains, California · 42 km E of this epicentre
  5. 5.5 1 km WNW of Davenport, California · 30 km SE 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 37.1757, -122.4753. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
San Mateo County, CA 28 km (17 mi) NNE earthquakes near San Mateo County
Santa Cruz County, CA 45 km (28 mi) ESE earthquakes near Santa Cruz County
Santa Clara County, CA 70 km (43 mi) E earthquakes near Santa Clara County
Alameda County, CA 72 km (45 mi) NE earthquakes near Alameda County
San Francisco County, CA 79 km (49 mi) NW earthquakes near San Francisco County
Contra Costa County, CA 95 km (59 mi) NNE earthquakes near Contra Costa County

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

57 earthquakes have been recorded within 50 km since this one.

  1. 2.1 2 km NE of Millbrae, CA
  2. 1.6 3 km SE of Pacifica, CA
  3. 2.0 3 km SE of Pacifica, CA
  4. 2.3 10 km SW of Bonny Doon, CA
  5. 2.1 3 km SE of Pacifica, CA
  6. 1.8 24 km WNW of Boulder Creek, CA
  7. 2.1 3 km SE of Pacifica, CA
  8. 1.8 3 km SE of Pacifica, CA
  9. 1.6 3 km SE of Pacifica, CA
  10. 1.5 3 km SE of Pacifica, CA
  11. 2.0 2 km SE of Pacifica, CA
  12. 1.5 3 km SE of Pacifica, CA
  13. 1.6 2 km SE of Pacifica, CA
  14. 1.6 4 km SE of Pacifica, CA
  15. 1.6 2 km SE of Pacifica, 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

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.