QuakeIndex

Earthquake · reviewed by a seismologist

M 4.6mw

1 km SE of Boulder Creek, CA

· 10 km deep · released about 120 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Santa Cruz County 15 kmSanta Clara County 39 kmSan Mateo County 40 kmAlameda County 62 kmContra Costa County 91 kmSan Francisco County 106 kmSan Benito County 107 kmStanislaus County 110 kmSan Joaquin County 117 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 4.6 (mw)
Depth
10 km below the surface
Felt
33078 reports · strongest reported intensity VI
Measured shaking
intensity VI (ShakeMap)
USGS impact alert
green
Nearest
Santa Cruz County, 15 km SE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon. 33078 people have reported feeling it to USGS.

How big was it?

This earthquake released about 120 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.6 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 1,500× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 65× the energy of this one
  3. Magna, Utah 2020 M 5.7 46× the energy of this one
  4. This earthquake M 4.6 about 120 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 240× 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.

Where

Epicentre 37.1157, -122.1125. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Santa Cruz County, CA 15 km (9 mi) NW of here earthquakes near Santa Cruz County
Santa Clara County, CA 39 km (24 mi) WSW of here earthquakes near Santa Clara County
San Mateo County, CA 40 km (25 mi) SE of here earthquakes near San Mateo County
Alameda County, CA 62 km (38 mi) SSW of here earthquakes near Alameda County
Contra Costa County, CA 91 km (56 mi) S of here earthquakes near Contra Costa County
San Francisco County, CA 106 km (66 mi) SE 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

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

  1. 1.8 7 km WSW of Gilroy, CA
  2. 1.5 3 km ESE of Woodside, CA
  3. 1.8 3 km NNE of Portola Valley, CA
  4. 1.7 6 km SSE of Portola Valley, CA
  5. 1.9 3 km NNE of Portola Valley, CA
  6. 1.8 15 km E of Seven Trees, CA
  7. 2.1 9 km ENE of Morgan Hill, CA
  8. 1.7 4 km ESE of Interlaken, CA
  9. 1.6 2 km ENE of Aromas, CA
  10. 2.1 15 km N of Morgan Hill, CA
  11. 2.2 8 km NE of Alum Rock, CA
  12. 1.6 2 km ENE of Aromas, CA
  13. 2.3 14 km N of Morgan Hill, CA
  14. 1.6 2 km W of Portola Valley, CA
  15. 1.6 7 km WSW of Gilroy, 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 5.1 on 2022-10-25 — it released about 5.1 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.