QuakeIndex

Earthquake · reviewed by a seismologist

M 2.6md

Earthquake near Saratoga, CA

No earthquake was likely felt in Saratoga in the 24 hours to 9:00 pm PST (05:00 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 2.6 earthquake was recorded 12 km (7 mi) west of Saratoga, CA, at 3:13 am PST on 31 January 2020 (11:13 UTC), 12 km deep. 33 people have reported feeling it to USGS.

USGS: 12km W of Saratoga, CA

13 km (8 mi) SW of Cupertino, CA · 31 km (19 mi) W of San Jose, CA

3:13 am PST, Jan 31, 2020 · · 12 km deep · released about 280 lb of TNT

10 km30 km60 km120 km N San Mateo County 26 kmSanta Cruz County 29 kmSanta Clara County 42 kmAlameda County 49 kmContra Costa County 77 kmSan Francisco County 94 kmMarin County 103 kmStanislaus County 108 kmSan Joaquin County 109 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
3:13 am PST on 31 January 2020 ()
Where
12 km (7 mi) west of Saratoga, CA · earthquakes near Saratoga
Magnitude
M 2.6 (md)
Depth
12 km below the surface
Felt
33 reports · strongest reported intensity III
Nearest
San Mateo County, 26 km NW
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 2126 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 21 km (13 mi) from the epicentre. In Saratoga, 12 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: Saratoga 12 km, intensity II · Cupertino 14 km, intensity II · Boulder Creek 14 km, intensity II · Los Altos 16 km, intensity II · Los Gatos 16 km, intensity II · Mountain View 17 km, intensity II · Sunnyvale 17 km, intensity II · Campbell 19 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 280 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 53,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 38,000× the energy of this one
  3. Around the size people start to feel M 3.0 3.3× the energy of this one
  4. This earthquake M 2.6 about 280 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 140 times the energy of this one.

Before 2016, the USGS record lists 20 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.9 The 1989 Loma Prieta, California Earthquake · 34 km SE of this epicentre
  2. 6.5 Near Morgan Hill, California · 49 km ESE of this epicentre
  3. 6.3 22 km S of Davenport, California · 49 km S of this epicentre
  4. 6.3 16 km SW of Davenport, California · 40 km SSW of this epicentre
  5. 6.2 Near San Jose, California · 32 km E 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 37.2490, -122.1578. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
San Mateo County, CA 26 km (16 mi) NW earthquakes near San Mateo County
Santa Cruz County, CA 29 km (18 mi) SSE earthquakes near Santa Cruz County
Santa Clara County, CA 42 km (26 mi) E earthquakes near Santa Clara County
Alameda County, CA 49 km (31 mi) NNE earthquakes near Alameda County
Contra Costa County, CA 77 km (48 mi) NNE earthquakes near Contra Costa County
San Francisco County, CA 94 km (58 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

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

  1. 1.8 3km W of Portola Valley, CA
  2. 1.8 2km SW of Los Altos Hills, CA
  3. 3.4 8km NE of Alum Rock, CA
  4. 2.1 8km ENE of Alum Rock, CA
  5. 1.6 15km E of Seven Trees, CA
  6. 2.2 5km SSE of Newark, CA
  7. 1.8 12km WNW of Boulder Creek, CA
  8. 2.2 13km ESE of Seven Trees, CA
  9. 1.7 11km E of Alum Rock, CA
  10. 2.3 11km E of Alum Rock, CA
  11. 1.5 11km ESE of Alum Rock, CA
  12. 2.3 11km ESE of Alum Rock, CA
  13. 2.4 11km ESE of Alum Rock, CA
  14. 2.2 11km ESE of Alum Rock, CA
  15. 2.3 11km E of Alum Rock, 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.