QuakeIndex

Earthquake · reviewed by a seismologist

M 1.5md

18km WSW of Westley, CA

· 0.2 km deep · released about 5.9 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Stanislaus County 35 kmSanta Clara County 40 kmAlameda County 50 kmSan Joaquin County 51 kmMerced County 67 kmContra Costa County 70 kmSanta Cruz County 76 kmSan Mateo County 87 kmSolano 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 1.5 (md)
Depth
0.2 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 2655 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 5.9 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,500,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,800,000× the energy of this one
  3. Around the size people start to feel M 3.0 160× the energy of this one
  4. This earthquake M 1.5 about 5.9 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 37.4832, -121.3845. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Stanislaus County, CA 35 km (22 mi) WSW of here earthquakes near Stanislaus County
Santa Clara County, CA 40 km (25 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 51 km (32 mi) S of here earthquakes near San Joaquin County
Merced County, CA 67 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

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

  1. 1.9 11km N of Morgan Hill, CA
  2. 3.3 8km ENE of Alum Rock, CA
  3. 1.9 8km ENE of San Martin, CA
  4. 2.1 20km NE of Morgan Hill, CA
  5. 1.6 19km NE of Morgan Hill, CA
  6. 2.0 9km ENE of Milpitas, CA
  7. 1.8 5km NNE of Alum Rock, CA
  8. 1.5 16km N of Morgan Hill, CA
  9. 1.7 11km NE of Milpitas, CA
  10. 1.9 12km ENE of Milpitas, CA
  11. 2.5 8km NE of Alum Rock, CA
  12. 1.6 9km NE of Milpitas, CA
  13. 2.4 11km NE of Milpitas, CA
  14. 2.5 10km E of Alum Rock, CA
  15. 2.6 14km N of Morgan Hill, 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 6,900 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.