QuakeIndex

Earthquake · reviewed by a seismologist

M 3.4mw

10km NE of Milpitas, CA

· 5.3 km deep · released about 2 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Alameda County 19 kmSanta Clara County 32 kmContra Costa County 49 kmSan Mateo County 49 kmSanta Cruz County 56 kmSan Joaquin County 69 kmStanislaus County 73 kmSolano County 87 kmMarin County 102 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 3.4 (mw)
Depth
5.3 km below the surface
Felt
1065 reports · strongest reported intensity IV
Nearest
Alameda County, 19 km NNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2112 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 1065 people have reported feeling it to USGS.

How big was it?

This earthquake released about 2 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.4 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 83,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 3,700× the energy of this one
  3. Magna, Utah 2020 M 5.7 2,600× the energy of this one
  4. This earthquake M 3.4 about 2 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 4.3× 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 37.4917, -121.8247. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Alameda County, CA 19 km (12 mi) SSE of here earthquakes near Alameda County
Santa Clara County, CA 32 km (20 mi) NNW of here earthquakes near Santa Clara County
Contra Costa County, CA 49 km (30 mi) SSE of here earthquakes near Contra Costa County
San Mateo County, CA 49 km (30 mi) E of here earthquakes near San Mateo County
Santa Cruz County, CA 56 km (35 mi) NNE of here earthquakes near Santa Cruz County
San Joaquin County, CA 69 km (43 mi) SW of here earthquakes near San Joaquin County

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

Aftershocks so far

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

  1. 1.5 8km ENE of Alum Rock, CA
  2. 1.7 10km NNE of San Martin, CA
  3. 1.6 9km NE of Milpitas, CA
  4. 1.7 7km N of Day Valley, CA
  5. 2.1 4km ESE of Hayward, CA
  6. 2.1 4km WNW of Dublin, CA
  7. 1.7 4km WNW of Dublin, CA
  8. 1.7 4km WNW of Dublin, CA
  9. 2.3 4km WNW of Dublin, CA
  10. 3.5 10km ENE of Morgan Hill, CA
  11. 3.7 10km ENE of Morgan Hill, CA
  12. 1.7 5km S of Blackhawk, CA
  13. 1.6 8km ENE of Alum Rock, CA
  14. 1.6 3km ESE of Highlands-Baywood Park, CA
  15. 2.2 11km NE of Milpitas, 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 4.3 on 2019-07-16 — it released about 22 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.