QuakeIndex

Earthquake · reviewed by a seismologist

M 2.5md

22km W of Westley, CA

· 2.5 km deep · released about 190 lb of TNT

10 km30 km60 km120 km N Santa Clara County 39 kmStanislaus County 39 kmAlameda County 44 kmSan Joaquin County 49 kmContra Costa County 64 kmMerced County 73 kmSanta Cruz County 75 kmSan Mateo County 83 kmSolano County 95 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 2.5 (md)
Depth
2.5 km below the surface
Felt
22 reports · strongest reported intensity III
Nearest
Santa Clara County, 39 km SW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3167 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 22 people have reported feeling it to USGS.

How big was it?

This earthquake released about 190 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 78,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 55,000× the energy of this one
  3. Around the size people start to feel M 3.0 4.9× the energy of this one
  4. This earthquake M 2.5 about 190 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 37.5108, -121.4422. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Santa Clara County, CA 39 km (24 mi) NE of here earthquakes near Santa Clara County
Stanislaus County, CA 39 km (24 mi) W of here earthquakes near Stanislaus County
Alameda County, CA 44 km (27 mi) ESE of here earthquakes near Alameda County
San Joaquin County, CA 49 km (31 mi) SSW of here earthquakes near San Joaquin County
Contra Costa County, CA 64 km (40 mi) SE of here earthquakes near Contra Costa County
Merced County, CA 73 km (45 mi) WNW of here earthquakes near Merced County

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

Aftershocks so far

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

  1. 1.7 6km E of Fremont, CA
  2. 1.8 9km ENE of Milpitas, CA
  3. 1.8 6km W of French Camp, CA
  4. 1.8 9km E of Livermore, CA
  5. 2.0 12km SSW of Mountain House, CA
  6. 2.5 8km ENE of San Martin, CA
  7. 2.9 16km E of Seven Trees, CA
  8. 1.6 10km NNE of Alum Rock, CA
  9. 2.0 15km E of Seven Trees, CA
  10. 3.0 16km N of Morgan Hill, CA
  11. 1.5 7km SE of Seven Trees, CA
  12. 1.5 9km SE of Livermore, CA
  13. 2.0 20km W of Westley, 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 210 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.