QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1md

9km NE of San Martin, CA

· 7.0 km deep · released about 40 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Santa Clara County 17 kmSanta Cruz County 44 kmAlameda County 66 kmStanislaus County 66 kmSan Benito County 71 kmMerced County 72 kmSan Mateo County 80 kmSan Joaquin County 92 kmContra Costa 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
7.0 km below the surface
Felt
no reports yet
Nearest
Santa Clara County, 17 km WNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1353 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 40 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 5.8 380,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 270,000× the energy of this one
  3. Around the size people start to feel M 3.0 24× the energy of this one
  4. This earthquake M 2.1 about 40 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 37.1380, -121.5317. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Santa Clara County, CA 17 km (10 mi) ESE of here earthquakes near Santa Clara County
Santa Cruz County, CA 44 km (28 mi) ENE of here earthquakes near Santa Cruz County
Alameda County, CA 66 km (41 mi) SSE of here earthquakes near Alameda County
Stanislaus County, CA 66 km (41 mi) SW of here earthquakes near Stanislaus County
San Benito County, CA 71 km (44 mi) NW of here earthquakes near San Benito County
Merced County, CA 72 km (45 mi) W of here earthquakes near Merced County

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

Aftershocks so far

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

  1. 1.5 6km NNW of Aromas, CA
  2. 2.4 14km N of Morgan Hill, CA
  3. 1.8 5km SSE of San Juan Bautista, CA
  4. 1.9 5km SSE of San Juan Bautista, CA
  5. 1.5 13km NE of Hollister, CA
  6. 1.6 12km ENE of Milpitas, CA
  7. 1.6 12km ENE of Milpitas, CA
  8. 1.6 12km ENE of Milpitas, CA
  9. 2.5 9km ENE of San Martin, CA
  10. 1.8 9km ENE of San Martin, CA
  11. 1.7 9km ENE of San Martin, CA
  12. 2.0 9km ENE of San Martin, CA
  13. 1.8 8km ENE of Gilroy, CA
  14. 1.5 11km SW of Ridgemark, CA
  15. 1.7 15km E of Seven Trees, 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 5.1 on 2022-10-25 — it released about 30,000 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.