QuakeIndex

quarry blast · reviewed by a seismologist

M 1.9mh

10 km NE of Milpitas, California

· -0.5 km deep · released about 21 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Alameda County 20 kmSanta Clara County 32 kmSan Mateo County 50 kmContra Costa County 50 kmSanta Cruz County 55 kmSan Joaquin County 69 kmStanislaus County 72 kmSolano County 87 kmMerced 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 1.9 (mh)
Depth
-0.5 km below the surface
Felt
2 reports · strongest reported intensity III
Nearest
Alameda County, 20 km NNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3300 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 2 people have reported feeling it to USGS.

USGS catalogues this as quarry blast, not an earthquake.

How big was it?

This earthquake released about 21 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 710,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 500,000× the energy of this one
  3. Around the size people start to feel M 3.0 45× the energy of this one
  4. This earthquake M 1.9 about 21 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 37.4863, -121.8175. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Alameda County, CA 20 km (12 mi) SSE of here earthquakes near Alameda County
Santa Clara County, CA 32 km (20 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 50 km (31 mi) SSE of here earthquakes near Contra Costa County
Santa Cruz County, CA 55 km (34 mi) NNE of here earthquakes near Santa Cruz County
San Joaquin County, CA 69 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

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

  1. 2.0 15km E of Seven Trees, CA
  2. 1.6 2km E of Diablo, CA
  3. 1.8 10km E of Alum Rock, CA
  4. 1.6 6km ENE of Dublin, CA
  5. 2.3 9km ENE of San Martin, CA
  6. 2.0 9km ENE of Milpitas, CA
  7. 2.6 2km NNE of San Leandro, CA
  8. 1.7 7km E of Alum Rock, CA
  9. 1.9 4km NE of Portola Valley, CA
  10. 1.7 5km NNE of San Leandro, CA
  11. 1.6 3 km W of Portola Valley, California
  12. 1.8 4 km WNW of La Honda, California
  13. 1.5 11 km ESE of East Foothills, California
  14. 1.7 1 km N of North Fair Oaks, California
  15. 1.9 14 km E of Seven Trees, California

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.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.