QuakeIndex

Earthquake · reviewed by a seismologist

M 3.6mw

13km ESE of Alum Rock, CA

· 8.2 km deep · released about 3.7 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Santa Clara County 12 kmAlameda County 41 kmSanta Cruz County 45 kmSan Mateo County 61 kmStanislaus County 66 kmContra Costa County 70 kmSan Joaquin County 77 kmMerced County 87 kmSan Benito County 96 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 3.6 (mw)
Depth
8.2 km below the surface
Felt
1267 reports · strongest reported intensity IV
Measured shaking
intensity IV (ShakeMap)
Nearest
Santa Clara County, 12 km S
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1154 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 1267 people have reported feeling it to USGS.

How big was it?

This earthquake released about 3.7 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.6 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 46,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 2,100× the energy of this one
  3. Magna, Utah 2020 M 5.7 1,500× the energy of this one
  4. This earthquake M 3.6 about 3.7 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 7.7× 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 37.3258, -121.6877. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Santa Clara County, CA 12 km (7 mi) N of here earthquakes near Santa Clara County
Alameda County, CA 41 km (25 mi) SSE of here earthquakes near Alameda County
Santa Cruz County, CA 45 km (28 mi) NE of here earthquakes near Santa Cruz County
San Mateo County, CA 61 km (38 mi) E of here earthquakes near San Mateo County
Stanislaus County, CA 66 km (41 mi) WSW of here earthquakes near Stanislaus County
Contra Costa County, CA 70 km (43 mi) SSE of here earthquakes near Contra Costa County

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

Aftershocks so far

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

  1. 1.9 6km SSE of Portola Valley, CA
  2. 2.4 16km E of Seven Trees, CA
  3. 1.5 6km SW of Gilroy, CA
  4. 1.6 8km SE of Sunol, CA
  5. 1.8 9km ENE of San Martin, CA
  6. 2.2 9km ENE of San Martin, CA
  7. 1.8 9km ENE of San Martin, CA
  8. 3.6 9km ENE of San Martin, CA
  9. 1.7 1km SE of Portola Valley, CA
  10. 1.6 1km SE of Portola Valley, CA
  11. 2.3 1km ESE of Portola Valley, CA
  12. 1.5 8km SSW of Livermore, CA
  13. 2.0 1km SE of Portola Valley, CA
  14. 2.2 5km S of Loyola, CA
  15. 2.4 1km SE of Portola Valley, 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 160 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.