QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

4 km N of East Foothills, California

· 0.1 km deep · released about 17 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Santa Clara County 24 kmAlameda County 27 kmSanta Cruz County 48 kmSan Mateo County 49 kmContra Costa County 57 kmStanislaus County 73 kmSan Joaquin County 75 kmSolano County 95 kmMerced 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 1.8 (md)
Depth
0.1 km below the surface
Felt
no reports yet
Nearest
Santa Clara County, 24 km SSE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3299 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 17 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 900,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 640,000× the energy of this one
  3. Around the size people start to feel M 3.0 57× the energy of this one
  4. This earthquake M 1.8 about 17 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 37.4178, -121.8125. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Santa Clara County, CA 24 km (15 mi) NNW of here earthquakes near Santa Clara County
Alameda County, CA 27 km (17 mi) SSE of here earthquakes near Alameda County
Santa Cruz County, CA 48 km (30 mi) NNE of here earthquakes near Santa Cruz County
San Mateo County, CA 49 km (31 mi) E of here earthquakes near San Mateo County
Contra Costa County, CA 57 km (35 mi) SSE of here earthquakes near Contra Costa County
Stanislaus County, CA 73 km (45 mi) WSW of here earthquakes near Stanislaus County

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

Aftershocks so far

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

  1. 1.6 13km SSE of Livermore, CA
  2. 2.0 15km E of Seven Trees, CA
  3. 1.6 2km E of Diablo, CA
  4. 1.8 10km E of Alum Rock, CA
  5. 1.6 6km ENE of Dublin, CA
  6. 2.3 9km ENE of San Martin, CA
  7. 2.0 9km ENE of Milpitas, CA
  8. 2.6 2km NNE of San Leandro, CA
  9. 1.7 7km E of Alum Rock, CA
  10. 1.9 4km NE of Portola Valley, CA
  11. 1.7 5km NNE of San Leandro, CA
  12. 1.6 3 km W of Portola Valley, California
  13. 1.8 4 km WNW of La Honda, California
  14. 1.5 11 km ESE of East Foothills, California
  15. 1.9 9 km NE of Gilroy, California

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.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.