QuakeIndex

quarry blast · reviewed by a seismologist

M 1.5md

3km S of Loyola, CA

· -0.3 km deep · released about 5.7 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N San Mateo County 26 kmSanta Cruz County 36 kmSanta Clara County 38 kmAlameda County 40 kmContra Costa County 68 kmSan Francisco County 93 kmMarin County 99 kmSan Joaquin County 100 kmStanislaus County 101 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
-0.3 km below the surface
Felt
no reports yet
Nearest
San Mateo County, 26 km WNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2852 days ago

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

USGS catalogues this as quarry blast, not an earthquake.

How big was it?

This earthquake released about 5.7 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 2,600,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,900,000× the energy of this one
  3. Around the size people start to feel M 3.0 170× the energy of this one
  4. This earthquake M 1.5 about 5.7 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 37.3228, -122.1038. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
San Mateo County, CA 26 km (16 mi) ESE of here earthquakes near San Mateo County
Santa Cruz County, CA 36 km (22 mi) NNW of here earthquakes near Santa Cruz County
Santa Clara County, CA 38 km (24 mi) WNW of here earthquakes near Santa Clara County
Alameda County, CA 40 km (25 mi) SSW of here earthquakes near Alameda County
Contra Costa County, CA 68 km (42 mi) SSW of here earthquakes near Contra Costa County
San Francisco County, CA 93 km (58 mi) ESE of here earthquakes near San Francisco County

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

Aftershocks so far

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

  1. 1.6 8km SE of Seven Trees, CA
  2. 1.8 2km NE of San Leandro, CA
  3. 2.5 12km NNE of Morgan Hill, CA
  4. 2.3 12km NNE of Morgan Hill, CA
  5. 2.9 12km NNE of Morgan Hill, CA
  6. 2.0 3km E of Union City, CA
  7. 1.7 5km WNW of Sunol, CA
  8. 1.7 2km NNW of San Leandro, CA
  9. 1.5 3km S of Loyola, CA
  10. 2.3 8km E of Alum Rock, CA
  11. 1.7 11km SE of Livermore, CA
  12. 2.5 12km NNE of Morgan Hill, CA
  13. 1.8 8km SSE of Portola Valley, CA
  14. 2.1 3km SW of Monte Sereno, CA
  15. 2.0 11km NNE of Alum Rock, 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 7,200 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.