QuakeIndex

Earthquake · reviewed by a seismologist

M 3.1ml

9km ENE of San Martin, CA

· 7.3 km deep · released about 1,200 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Santa Clara County 18 kmSanta Cruz County 45 kmStanislaus County 67 kmAlameda County 67 kmSan Benito County 69 kmMerced County 72 kmSan Mateo County 81 kmSan Joaquin County 93 kmContra Costa County 96 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 3.1 (ml)
Depth
7.3 km below the surface
Felt
92 reports · strongest reported intensity IV
Nearest
Santa Clara County, 18 km NW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2531 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 92 people have reported feeling it to USGS.

How big was it?

This earthquake released about 1,200 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.1 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 290,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 13,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 9,100× the energy of this one
  4. This earthquake M 3.1 about 1,200 lb of TNT
  5. Around the size people start to feel M 3.0 this one released 1.2× more

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 37.1252, -121.5265. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Santa Clara County, CA 18 km (11 mi) SE of here earthquakes near Santa Clara County
Santa Cruz County, CA 45 km (28 mi) ENE of here earthquakes near Santa Cruz County
Stanislaus County, CA 67 km (42 mi) SW of here earthquakes near Stanislaus County
Alameda County, CA 67 km (42 mi) SSE of here earthquakes near Alameda County
San Benito County, CA 69 km (43 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

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

  1. 1.7 8km ENE of Gilroy, CA
  2. 1.7 17km SE of Livermore, CA
  3. 2.5 3km WSW of San Juan Bautista, CA
  4. 1.8 9km NNE of Alum Rock, CA
  5. 1.6 11km NE of Milpitas, CA
  6. 1.7 11km WSW of Ridgemark, CA
  7. 2.8 9km ENE of Milpitas, CA
  8. 2.4 24km SW of Gustine, CA
  9. 1.6 7km NE of Ridgemark, CA
  10. 2.5 9km NE of San Martin, CA
  11. 3.4 9km ENE of Milpitas, CA
  12. 2.0 5km WNW of San Juan Bautista, CA
  13. 1.8 23km SW of Gustine, CA
  14. 1.6 8km NE of Alum Rock, CA
  15. 2.3 6km SW of Ridgemark, 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 4.1 on 2017-10-10 — it released about 35 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.