QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7md

Earthquake near Stanford, CA

No earthquake was likely felt in Stanford in the 24 hours to 12:47 am PST (08:47 UTC). The last one was M 2.0, 15 km (9 mi) SSE, at 9:23 am PST on 10 November 2026, estimated intensity II (weak) in town; 4 felt reports to USGS. Every earthquake near Stanford

This page: a magnitude 1.7 earthquake was recorded 4 km (2 mi) southwest of Stanford, CA, at 9:30 am PST on 23 January 2018 (17:30 UTC), 4.0 km deep.

USGS: 4km SW of Stanford, CA

in Palo Alto, CA · 36 km (22 mi) WNW of San Jose, CA

9:30 am PST, Jan 23, 2018 · · 4.0 km deep · released about 9.3 lb of TNT

10 km30 km60 km120 km N San Mateo County 15 kmAlameda County 37 kmSanta Cruz County 47 kmSanta Clara County 49 kmContra Costa County 61 kmSan Francisco County 82 kmMarin County 87 kmSolano County 99 kmSan Joaquin County 101 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
9:30 am PST on 23 January 2018 ()
Where
4 km (2 mi) southwest of Stanford, CA · earthquakes near Stanford
Magnitude
M 1.7 (md)
Depth
4.0 km below the surface
Felt
no reports yet
Nearest
San Mateo County, 15 km W
Nearest mapped fault
Monte Vista-Shannon fault, 2 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 3204 days ago

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 11 km (7 mi) from the epicentre. In Stanford, 4 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: Menlo Park 6 km, intensity II · Palo Alto 7 km, intensity II · Los Altos 8 km, intensity II · East Palo Alto 9 km, intensity II · Redwood City 10 km, intensity II · Mountain View 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 9.3 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,600,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,100,000× the energy of this one
  3. Around the size people start to feel M 3.0 100× the energy of this one
  4. This earthquake M 1.7 about 9.3 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 4,400 times the energy of this one.

Before 2016, the USGS record lists 16 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.9 The 1906 San Francisco, California Earthquake · 50 km NW of this epicentre
  2. 6.9 The 1989 Loma Prieta, California Earthquake · 50 km SE of this epicentre
  3. 6.2 Near San Jose, California · 37 km ESE of this epicentre
  4. 6.2 The 1984 Morgan Hill, California Earthquake · 47 km ESE of this epicentre
  5. 6.1 Near San Jose, California · 42 km ESE 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 37.4025, -122.1978. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
San Mateo County, CA 15 km (10 mi) W earthquakes near San Mateo County
Alameda County, CA 37 km (23 mi) NE earthquakes near Alameda County
Santa Cruz County, CA 47 km (29 mi) SSE earthquakes near Santa Cruz County
Santa Clara County, CA 49 km (31 mi) ESE earthquakes near Santa Clara County
Contra Costa County, CA 61 km (38 mi) NNE earthquakes near Contra Costa County
San Francisco County, CA 82 km (51 mi) WNW earthquakes near San Francisco County

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

Aftershocks so far

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

  1. 1.7 2km E of Hayward, CA
  2. 1.7 6km E of Fremont, CA
  3. 2.0 5km WSW of Daly City, CA
  4. 1.8 9km ENE of Milpitas, CA
  5. 1.6 3km NNE of San Leandro, CA
  6. 1.8 4km WNW of San Francisco Zoo, CA
  7. 1.7 7km WNW of Lexington Hills, CA
  8. 1.8 3km SE of Oakland, CA
  9. 2.9 16km E of Seven Trees, CA
  10. 1.6 4km WNW of San Francisco Zoo, CA
  11. 1.6 10km NNE of Alum Rock, CA
  12. 2.0 15km 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

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