QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1md

Earthquake near East Foothills, CA

Yes. A magnitude 2.1 earthquake was recorded 6 km (4 mi) ESE of East Foothills, CA, at 11:22 pm PDT on 27 April 2016 (06:22 UTC), less than 1 km deep. 3 people have reported feeling it to USGS.

This was on 27 April 2016. The latest near East Foothills: M 2.5 on 19 September 2026.

USGS: 6 km ESE of East Foothills, California

9 km (5 mi) NE of San Jose, CA

11:22 pm PDT, Apr 27, 2016 · · 0.5 km deep · released about 37 lb of TNT

10 km30 km60 km120 km N Santa Clara County 16 kmAlameda County 35 kmSanta Cruz County 45 kmSan Mateo County 55 kmContra Costa County 65 kmStanislaus County 70 kmSan Joaquin County 77 kmMerced County 93 kmSan Benito County 102 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
11:22 pm PDT on 27 April 2016 ()
Where
6 km (4 mi) ESE of East Foothills, CA · earthquakes near East Foothills
Magnitude
M 2.1 (md)
Depth
0.5 km below the surface
Felt
3 reports · strongest reported intensity II
Nearest
Santa Clara County, 16 km SSE
Nearest mapped fault
Calaveras fault, 1 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 1533 days ago

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

At this magnitude and depth, people at rest would likely notice it out to about 17 km (11 mi) from the epicentre. In East Foothills, 6 km away, the estimate is intensity II (weak). Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

Likely felt in: East Foothills 6 km, intensity II · San Jose 13 km, intensity II · Milpitas 16 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 37 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 410,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 290,000× the energy of this one
  3. Around the size people start to feel M 3.0 26× the energy of this one
  4. This earthquake M 2.1 about 37 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 23 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.9 The 1989 Loma Prieta, California Earthquake · 38 km SSW of this epicentre
  2. 6.5 Near Morgan Hill, California · 29 km SSE of this epicentre
  3. 6.2 Near San Jose, California · 8 km SSW of this epicentre
  4. 6.2 The 1984 Morgan Hill, California Earthquake · 9 km SE of this epicentre
  5. 6.1 Near San Jose, California · 18 km SSW 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 37.3587, -121.7543. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Santa Clara County, CA 16 km (10 mi) SSE earthquakes near Santa Clara County
Alameda County, CA 35 km (22 mi) NNW earthquakes near Alameda County
Santa Cruz County, CA 45 km (28 mi) SSW earthquakes near Santa Cruz County
San Mateo County, CA 55 km (34 mi) W earthquakes near San Mateo County
Contra Costa County, CA 65 km (40 mi) NNW earthquakes near Contra Costa County
Stanislaus County, CA 70 km (44 mi) ENE earthquakes near Stanislaus 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. 1.8 5 km SSE of Loyola, California
  2. 2.2 9 km NNE of East Foothills, California
  3. 1.6 6 km ENE of East Foothills, California
  4. 1.7 13 km E of Livermore, California
  5. 1.7 12 km ESE of Livermore, California
  6. 1.9 7 km WSW of Gilroy, California
  7. 1.6 3 km S of Loyola, California
  8. 2.1 9 km E of Gilroy, California
  9. 1.7 8 km SSE of Sunol, California
  10. 1.8 8 km ENE of Morgan Hill, California
  11. 1.6 8 km S of Sunol, California
  12. 1.6 3 km S of Loyola, California
  13. 2.1 7 km WSW of Gilroy, California
  14. 2.0 17 km NE of San Martin, California
  15. 2.3 9 km E 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.