QuakeIndex

Earthquake · reviewed by a seismologist

M 2.3md

4km SSW of Los Altos Hills, CA

· 6.7 km deep · released about 77 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N San Mateo County 20 kmAlameda County 40 kmSanta Cruz County 40 kmSanta Clara County 44 kmContra Costa County 66 kmSan Francisco County 88 kmMarin County 94 kmSan Joaquin County 102 kmSolano County 104 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
Magnitude
M 2.3 (md)
Depth
6.7 km below the surface
Felt
10 reports · strongest reported intensity II
Nearest
San Mateo County, 20 km WNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2746 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 10 people have reported feeling it to USGS.

How big was it?

This earthquake released about 77 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.3 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 200,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 140,000× the energy of this one
  3. Around the size people start to feel M 3.0 12× the energy of this one
  4. This earthquake M 2.3 about 77 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.

Where

Epicentre 37.3487, -122.1588. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
San Mateo County, CA 20 km (13 mi) ESE of here earthquakes near San Mateo County
Alameda County, CA 40 km (25 mi) SSW of here earthquakes near Alameda County
Santa Cruz County, CA 40 km (25 mi) NNW of here earthquakes near Santa Cruz County
Santa Clara County, CA 44 km (27 mi) WNW of here earthquakes near Santa Clara County
Contra Costa County, CA 66 km (41 mi) SSW of here earthquakes near Contra Costa County
San Francisco County, CA 88 km (55 mi) ESE of here earthquakes near San Francisco County

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

Aftershocks so far

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

  1. 2.0 5km N of San Leandro, CA
  2. 2.1 8km E of Alum Rock, CA
  3. 2.3 2km E of Bonny Doon, CA
  4. 1.6 22km NE of Alum Rock, CA
  5. 1.6 20km WNW of Boulder Creek, CA
  6. 1.8 21km W of Boulder Creek, CA
  7. 2.5 20km WNW of Boulder Creek, CA
  8. 2.8 21km WNW of Boulder Creek, CA
  9. 1.9 20km WNW of Boulder Creek, CA
  10. 2.0 6km WSW of Colma, CA
  11. 2.2 5km WSW of Cupertino, CA
  12. 1.8 10km E of Alum Rock, CA
  13. 2.6 4km ESE of Oakland, CA
  14. 2.9 3km NNE of Corralitos, CA
  15. 1.6 14km SSE of Livermore, 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.

For this area

The largest earthquake within 50 km in our catalogue was M 4.1 on 2017-10-10 — it released about 540 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

On USGS

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