QuakeIndex

Earthquake · reviewed by a seismologist

M 2.9md

12km NNE of Morgan Hill, CA

· 5.4 km deep · released about 650 lb of TNT

10 km30 km60 km120 km N Santa Clara County 6 kmSanta Cruz County 42 kmAlameda County 53 kmStanislaus County 65 kmSan Mateo County 69 kmMerced County 80 kmContra Costa County 81 kmSan Joaquin County 84 kmSan Benito 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 2.9 (md)
Depth
5.4 km below the surface
Felt
96 reports · strongest reported intensity IV
Nearest
Santa Clara County, 6 km WSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2739 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 96 people have reported feeling it to USGS.

How big was it?

This earthquake released about 650 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 23,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 16,000× the energy of this one
  3. Around the size people start to feel M 3.0 1.5× the energy of this one
  4. This earthquake M 2.9 about 650 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 37.2360, -121.6195. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Santa Clara County, CA 6 km (4 mi) ENE of here earthquakes near Santa Clara County
Santa Cruz County, CA 42 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) WSW of here earthquakes near Stanislaus County
San Mateo County, CA 69 km (43 mi) ESE of here earthquakes near San Mateo County
Merced County, CA 80 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

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

  1. 3.0 3km ESE of Aromas, CA
  2. 1.6 10km N of Boulder Creek, CA
  3. 1.5 18km WSW of Westley, CA
  4. 1.6 3km E of Aromas, CA
  5. 1.8 15km N of Hollister, CA
  6. 1.8 6km SW of Gilroy, CA
  7. 1.8 6km W of Hollister, CA
  8. 1.5 3km E of Aromas, CA
  9. 1.8 8km NE of Alum Rock, CA
  10. 2.4 9km ENE of San Martin, CA
  11. 2.3 13km NNE of Morgan Hill, CA
  12. 1.8 10km ENE of Milpitas, CA
  13. 1.6 8km NE of Alum Rock, CA
  14. 1.7 10km E of Alum Rock, CA
  15. 1.6 6km SSW 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 4.1 on 2017-10-10 — it released about 63 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.