QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6md

18km WSW of Westley, CA

· 5.5 km deep · released about 7.3 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Stanislaus County 35 kmSanta Clara County 39 kmAlameda County 50 kmSan Joaquin County 52 kmMerced County 66 kmContra Costa County 70 kmSanta Cruz County 76 kmSan Mateo County 87 kmSan Benito County 100 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 1.6 (md)
Depth
5.5 km below the surface
Felt
no reports yet
Nearest
Stanislaus County, 35 km ENE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1382 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

How big was it?

This earthquake released about 7.3 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,100,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,500,000× the energy of this one
  3. Around the size people start to feel M 3.0 130× the energy of this one
  4. This earthquake M 1.6 about 7.3 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 37.4790, -121.3843. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Stanislaus County, CA 35 km (22 mi) WSW of here earthquakes near Stanislaus County
Santa Clara County, CA 39 km (24 mi) NE of here earthquakes near Santa Clara County
Alameda County, CA 50 km (31 mi) ESE of here earthquakes near Alameda County
San Joaquin County, CA 52 km (32 mi) S of here earthquakes near San Joaquin County
Merced County, CA 66 km (41 mi) WNW of here earthquakes near Merced County
Contra Costa County, CA 70 km (43 mi) SE 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

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

  1. 1.7 9km E of Alum Rock, CA
  2. 1.8 10km NE of Milpitas, CA
  3. 3.0 9km ENE of San Martin, CA
  4. 2.5 12km ESE of Alum Rock, CA
  5. 1.6 12km ESE of Alum Rock, CA
  6. 1.7 12km ESE of Alum Rock, CA
  7. 2.4 12km ESE of Alum Rock, CA
  8. 2.2 15km N of Morgan Hill, CA
  9. 1.6 16km E of Seven Trees, CA
  10. 2.4 10km NE of Gilroy, CA
  11. 2.3 15km E of Seven Trees, CA
  12. 3.0 16km E of Seven Trees, CA
  13. 1.6 11km N of Morgan Hill, CA
  14. 2.0 22km WSW of Gustine, CA
  15. 1.5 5km NE of San Martin, 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 160,000 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.