QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1md

15km ENE of Seven Trees, CA

· 7.7 km deep · released about 49 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Santa Clara County 10 kmAlameda County 43 kmSanta Cruz County 44 kmSan Mateo County 63 kmStanislaus County 66 kmContra Costa County 72 kmSan Joaquin County 78 kmMerced County 85 kmSan Benito County 94 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 2.1 (md)
Depth
7.7 km below the surface
Felt
no reports yet
Nearest
Santa Clara County, 10 km S
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1444 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 49 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 5.8 310,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 220,000× the energy of this one
  3. Around the size people start to feel M 3.0 19× the energy of this one
  4. This earthquake M 2.1 about 49 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 37.3118, -121.6760. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Santa Clara County, CA 10 km (6 mi) N of here earthquakes near Santa Clara County
Alameda County, CA 43 km (27 mi) SSE of here earthquakes near Alameda County
Santa Cruz County, CA 44 km (28 mi) NE of here earthquakes near Santa Cruz County
San Mateo County, CA 63 km (39 mi) E of here earthquakes near San Mateo County
Stanislaus County, CA 66 km (41 mi) WSW of here earthquakes near Stanislaus County
Contra Costa County, CA 72 km (45 mi) SSE of here earthquakes near Contra Costa County

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

Aftershocks so far

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

  1. 2.0 16km E of Seven Trees, CA
  2. 2.9 15km E of Seven Trees, CA
  3. 1.9 7km ESE of Pleasanton, CA
  4. 1.5 9km NNE of Milpitas, CA
  5. 1.7 3km SSE of Aptos Hills-Larkin Valley, CA
  6. 1.9 3km E of Morgan Hill, CA
  7. 2.0 7km ENE of Gilroy, CA
  8. 2.1 16km N of Morgan Hill, CA
  9. 1.6 6km ESE of Pleasanton, CA
  10. 1.6 15km N of Morgan Hill, CA
  11. 1.8 7km SE of Pleasanton, CA
  12. 2.8 9km NE of Alum Rock, CA
  13. 2.8 15km E of Seven Trees, CA
  14. 1.8 2km ENE of Aromas, CA
  15. 2.0 7km ESE of Pleasanton, 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 4.2 on 2021-01-17 — it released about 1,200 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.