QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

10 km NNE of East Foothills, California

· 8.5 km deep · released about 16 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Alameda County 23 kmSanta Clara County 28 kmContra Costa County 53 kmSan Mateo County 53 kmSanta Cruz County 55 kmSan Joaquin County 68 kmStanislaus County 69 kmSolano County 90 kmMerced County 98 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
8.5 km below the surface
Felt
no reports yet
Nearest
Alameda County, 23 km NNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3469 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 16 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 5.8 930,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 660,000× the energy of this one
  3. Around the size people start to feel M 3.0 59× the energy of this one
  4. This earthquake M 1.8 about 16 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 37.4670, -121.7762. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Alameda County, CA 23 km (15 mi) SSE of here earthquakes near Alameda County
Santa Clara County, CA 28 km (18 mi) NNW of here earthquakes near Santa Clara County
Contra Costa County, CA 53 km (33 mi) SSE of here earthquakes near Contra Costa County
San Mateo County, CA 53 km (33 mi) E of here earthquakes near San Mateo County
Santa Cruz County, CA 55 km (34 mi) NNE of here earthquakes near Santa Cruz County
San Joaquin County, CA 68 km (42 mi) SW of here earthquakes near San Joaquin County

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

Aftershocks so far

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

  1. 1.7 3 km W of Byron, California
  2. 1.6 7 km N of Boulder Creek, California
  3. 1.6 4 km SSW of Byron, California
  4. 1.8 4 km ENE of La Honda, California
  5. 1.7 3 km WSW of Loyola, California
  6. 1.5 2 km S of Loyola, California
  7. 1.7 2 km NE of San Ramon, California
  8. 1.6 4 km NNW of Union City, California
  9. 2.0 19 km E of East Foothills, California
  10. 2.4 8 km ENE of San Martin, California
  11. 1.9 9 km NE of San Martin, California
  12. 1.7 4km NW of Castro Valley, CA
  13. 1.6 1 km SE of Lexington Hills, California
  14. 1.7 19 km ESE of East Foothills, California
  15. 2.3 1 km W of Danville, 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.