QuakeIndex

Earthquake · reviewed by a seismologist

M 2.4md

Earthquake near East Foothills, CA

USGS: 8 km NNE of East Foothills, California

18 km (11 mi) N of San Jose, CA · 10 km (6 mi) ENE of Milpitas, CA

10:09 pm PDT, Oct 9, 2016 · · 8.8 km deep · released about 110 lb of TNT

Every earthquake near East Foothills Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Alameda County 24 kmSanta Clara County 27 kmSan Mateo County 52 kmSanta Cruz County 53 kmContra Costa County 54 kmSan Joaquin County 70 kmStanislaus County 70 kmSolano County 91 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
10:09 pm PDT on 9 October 2016 ()
Where
9 km (6 mi) NNE of East Foothills, CA · earthquakes near East Foothills
Magnitude
M 2.4 (md)
Depth
8.8 km below the surface
Felt
no reports yet
Nearest
Alameda County, 24 km NNW
Nearest mapped fault
Calaveras fault, 3 km from its surface trace — near is not the same as on
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3521 days ago

A magnitude 2.4 earthquake was recorded 9 km (6 mi) NNE of East Foothills, CA, at 10:09 pm PDT on 9 October 2016 (05:09 UTC). This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

Earthquakes near other towns within 30 km: Milpitas, San Jose, Santa Clara, Fremont, Campbell, Newark.

How big was it?

This earthquake released about 110 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.4 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 140,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 99,000× the energy of this one
  3. Around the size people start to feel M 3.0 8.8× the energy of this one
  4. This earthquake M 2.4 about 110 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.

For this area

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

Before 2016, the USGS record lists 19 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.9 The 1989 Loma Prieta, California Earthquake · 48 km S of this epicentre
  2. 6.5 Near Morgan Hill, California · 41 km SSE of this epicentre
  3. 6.2 Near San Jose, California · 17 km S of this epicentre
  4. 6.2 The 1984 Morgan Hill, California Earthquake · 19 km SSE of this epicentre
  5. 6.1 Near San Jose, California · 29 km S of this epicentre

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Epicentre 37.4563, -121.7832. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Alameda County, CA 24 km (15 mi) NNW earthquakes near Alameda County
Santa Clara County, CA 27 km (17 mi) SSE earthquakes near Santa Clara County
San Mateo County, CA 52 km (32 mi) W earthquakes near San Mateo County
Santa Cruz County, CA 53 km (33 mi) SSW earthquakes near Santa Cruz County
Contra Costa County, CA 54 km (33 mi) NNW earthquakes near Contra Costa County
San Joaquin County, CA 70 km (43 mi) NE earthquakes near San Joaquin County

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

Aftershocks so far

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

  1. 2.0 14 km E of Seven Trees, California
  2. 2.1 6 km ENE of East Foothills, California
  3. 1.6 2 km ENE of San Leandro, California
  4. 1.5 Northern California
  5. 1.7 25 km SE of Livermore, California
  6. 1.7 1 km ENE of Alamo, California
  7. 1.8 3 km NNW of Castro Valley, California
  8. 2.1 3 km NNW of Castro Valley, California
  9. 2.4 6 km NE of East Foothills, California
  10. 2.1 15 km N of Morgan Hill, California
  11. 1.7 3 km S of Loyola, California
  12. 1.6 1 km SW of Blackhawk, California
  13. 2.1 0 km SW of Blackhawk, California
  14. 1.5 1 km SW of Blackhawk, California
  15. 1.6 0 km SW of Blackhawk, 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.