QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

11km NE of Milpitas, CA

· 4.2 km deep · released about 16 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Alameda County 18 kmSanta Clara County 33 kmContra Costa County 48 kmSan Mateo County 49 kmSanta Cruz County 56 kmSan Joaquin County 68 kmStanislaus County 72 kmSolano County 86 kmMarin County 102 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
4.2 km below the surface
Felt
no reports yet
Nearest
Alameda County, 18 km NNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1517 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 16 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 5.8 930,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 660,000× the energy of this one
  3. Around the size people start to feel M 3.0 59× the energy of this one
  4. This earthquake M 1.8 about 16 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 37.4982, -121.8210. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Alameda County, CA 18 km (11 mi) SSE of here earthquakes near Alameda County
Santa Clara County, CA 33 km (20 mi) NNW of here earthquakes near Santa Clara County
Contra Costa County, CA 48 km (30 mi) SSE of here earthquakes near Contra Costa County
San Mateo County, CA 49 km (31 mi) E of here earthquakes near San Mateo County
Santa Cruz County, CA 56 km (35 mi) NNE of here earthquakes near Santa Cruz County
San Joaquin County, CA 68 km (43 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

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

  1. 1.7 1km NE of Diablo, CA
  2. 1.5 2km S of Dublin, CA
  3. 1.8 9km NNE of Alum Rock, CA
  4. 2.1 15km ENE of Seven Trees, CA
  5. 1.8 6km SSE of Portola Valley, CA
  6. 1.9 6km SSE of Portola Valley, CA
  7. 2.1 2km NNE of San Leandro, CA
  8. 1.7 4km WNW of Dublin, CA
  9. 1.6 11km NE of Milpitas, CA
  10. 2.2 10km SE of Sunol, CA
  11. 2.1 10km ESE of Fremont, CA
  12. 1.8 24km SSE of Livermore, CA
  13. 1.9 8km WSW of Mountain House, CA
  14. 1.8 2km WNW of Los Altos Hills, CA
  15. 3.4 24km NE of Alum Rock, 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 4.3 on 2019-07-16 — it released about 5,400 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.