QuakeIndex

Earthquake · reviewed by a seismologist

M 3.3ml

12km NNE of Morgan Hill, CA

· 3.9 km deep · released about 1.3 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Santa Clara County 7 kmSanta Cruz County 43 kmAlameda County 53 kmStanislaus County 65 kmSan Mateo County 70 kmMerced County 79 kmContra Costa County 82 kmSan Benito County 84 kmSan Joaquin County 84 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 3.3 (ml)
Depth
3.9 km below the surface
Felt
103 reports · strongest reported intensity IV
Nearest
Santa Clara County, 7 km W
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1624 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 103 people have reported feeling it to USGS.

How big was it?

This earthquake released about 1.3 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.3 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 130,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 5,800× the energy of this one
  3. Magna, Utah 2020 M 5.7 4,100× the energy of this one
  4. This earthquake M 3.3 about 1.3 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 2.7× 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 37.2327, -121.6147. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Santa Clara County, CA 7 km (4 mi) E of here earthquakes near Santa Clara County
Santa Cruz County, CA 43 km (26 mi) NE of here earthquakes near Santa Cruz County
Alameda County, CA 53 km (33 mi) SSE of here earthquakes near Alameda County
Stanislaus County, CA 65 km (41 mi) SW of here earthquakes near Stanislaus County
San Mateo County, CA 70 km (43 mi) ESE of here earthquakes near San Mateo County
Merced County, CA 79 km (49 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

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

  1. 1.6 1km WNW of San Juan Bautista, CA
  2. 2.2 1km W of San Juan Bautista, CA
  3. 1.8 1km W of San Juan Bautista, CA
  4. 1.5 3km E of Aromas, CA
  5. 2.9 4km WSW of San Juan Bautista, CA
  6. 2.7 16km E of Seven Trees, CA
  7. 2.0 6km SW of Gilroy, CA
  8. 2.8 4km SE of Aromas, CA
  9. 1.9 16km E of Seven Trees, CA
  10. 1.6 10km NNE of Morgan Hill, CA
  11. 1.8 2km W of San Juan Bautista, CA
  12. 1.7 7km ENE of Gilroy, CA
  13. 1.9 8km E of Fremont, CA
  14. 2.3 9km E of Gilroy, CA
  15. 1.9 9km E of Gilroy, 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 23 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.