QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1md

Earthquake near Woodside, CA

No earthquake was likely felt in Woodside in the 24 hours to 5:41 am PST (13:41 UTC). The last one was M 1.9, in Woodside, at 4:14 pm PDT on 11 October 2026, estimated intensity II (weak) in town; 1 felt report to USGS. Every earthquake near Woodside

This page: a magnitude 2.1 earthquake was recorded 3 km (2 mi) west of Woodside, CA, at 12:04 pm PST on 1 February 2024 (20:04 UTC), 6.4 km deep.

USGS: 3 km W of Woodside, CA

12 km (7 mi) SW of Redwood City, CA · 45 km (28 mi) WNW of San Jose, CA

12:04 pm PST, Feb 1, 2024 · · 6.4 km deep · released about 43 lb of TNT

10 km30 km60 km120 km N San Mateo County 7 kmAlameda County 41 kmSanta Cruz County 53 kmSanta Clara County 58 kmContra Costa County 62 kmSan Francisco County 73 kmMarin County 80 kmSolano County 98 kmSan Joaquin County 106 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
12:04 pm PST on 1 February 2024 ()
Where
3 km (2 mi) west of Woodside, CA · earthquakes near Woodside
Magnitude
M 2.1 (md)
Depth
6.4 km below the surface
Felt
no reports yet
Nearest
San Mateo County, 7 km WSW
Nearest mapped fault
San Andreas 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 1004 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 16 km (10 mi) from the epicentre. In Woodside, 3 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: Redwood City 8 km, intensity II · San Carlos 9 km, intensity II · Menlo Park 10 km, intensity II · Belmont 10 km, intensity II · Half Moon Bay 13 km, intensity II · Palo Alto 13 km, intensity II · East Palo Alto 14 km, intensity II · Foster City 14 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 43 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 350,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 250,000× the energy of this one
  3. Around the size people start to feel M 3.0 22× the energy of this one
  4. This earthquake M 2.1 about 43 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 4.4 on 2018-01-04 — about 2,600 times the energy of this one.

Before 2016, the USGS record lists 12 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.9 The 1906 San Francisco, California Earthquake · 42 km NNW of this epicentre
  2. 6.2 Near San Jose, California · 46 km ESE of this epicentre
  3. 5.8 7 km NNW of Boulder Creek, California · 30 km SSE of this epicentre
  4. 5.5 Santa Cruz Mountains, California · 39 km SE of this epicentre
  5. 5.5 1 km WNW of Davenport, California · 47 km S 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 37.4318, -122.2907. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
San Mateo County, CA 7 km (5 mi) WSW earthquakes near San Mateo County
Alameda County, CA 41 km (26 mi) NE earthquakes near Alameda County
Santa Cruz County, CA 53 km (33 mi) SSE earthquakes near Santa Cruz County
Santa Clara County, CA 58 km (36 mi) ESE earthquakes near Santa Clara County
Contra Costa County, CA 62 km (38 mi) NNE earthquakes near Contra Costa County
San Francisco County, CA 73 km (45 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

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

  1. 1.8 4 km ENE of San Leandro, CA
  2. 2.1 2 km E of Berkeley, CA
  3. 2.5 7 km SSE of Sunol, CA
  4. 1.8 7 km SSE of Sunol, CA
  5. 1.6 8 km NE of Alum Rock, CA
  6. 2.3 8 km NE of Alum Rock, CA
  7. 3.4 8 km NE of Alum Rock, CA
  8. 1.5 4 km NNW of Pacifica, CA
  9. 2.3 9 km ESE of Fremont, CA
  10. 1.5 2 km SW of Alamo, CA
  11. 2.2 4 km N of San Leandro, CA
  12. 2.1 3 km NE of San Leandro, CA
  13. 2.0 3 km N of San Leandro, CA
  14. 2.4 3 km N of San Leandro, CA
  15. 2.1 22 km WNW of Boulder 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

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