QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

10km ENE of Milpitas, CA

· 3.4 km deep · released about 17 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Alameda County 22 kmSanta Clara County 29 kmSan Mateo County 50 kmContra Costa County 52 kmSanta Cruz County 53 kmSan Joaquin County 70 kmStanislaus County 72 kmSolano County 90 kmMerced County 101 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 1.8 (md)
Depth
3.4 km below the surface
Felt
no reports yet
Nearest
Alameda County, 22 km NNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2676 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 17 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 900,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 640,000× the energy of this one
  3. Around the size people start to feel M 3.0 57× the energy of this one
  4. This earthquake M 1.8 about 17 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 37.4662, -121.8077. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Alameda County, CA 22 km (14 mi) SSE of here earthquakes near Alameda County
Santa Clara County, CA 29 km (18 mi) NNW of here earthquakes near Santa Clara County
San Mateo County, CA 50 km (31 mi) E of here earthquakes near San Mateo County
Contra Costa County, CA 52 km (32 mi) SSE of here earthquakes near Contra Costa County
Santa Cruz County, CA 53 km (33 mi) NNE of here earthquakes near Santa Cruz County
San Joaquin County, CA 70 km (44 mi) SW of here earthquakes near San Joaquin 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. 1.8 5km NNE of Alum Rock, CA
  2. 1.7 3km E of Alamo, CA
  3. 1.5 16km N of Morgan Hill, CA
  4. 1.7 11km NE of Milpitas, CA
  5. 1.7 4km ESE of Oakland, CA
  6. 1.9 12km ENE of Milpitas, CA
  7. 2.5 8km NE of Alum Rock, CA
  8. 1.6 9km NE of Milpitas, CA
  9. 2.0 3km SSW of Alameda, CA
  10. 2.5 4km SW of Saratoga, CA
  11. 2.0 4km SW of Saratoga, CA
  12. 1.5 13km NNW of Boulder Creek, CA
  13. 2.5 3km N of San Leandro, CA
  14. 1.6 4km ESE of Moraga, CA
  15. 2.4 11km NE of Milpitas, 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 2,500 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.