QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6md

1km SSE of San Ramon, CA

· 7.8 km deep · released about 7.1 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Alameda County 14 kmContra Costa County 17 kmSan Mateo County 53 kmSolano County 56 kmSan Joaquin County 64 kmSanta Clara County 66 kmMarin County 75 kmSanta Cruz County 84 kmNapa County 88 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 1.6 (md)
Depth
7.8 km below the surface
Felt
no reports yet
Nearest
Alameda County, 14 km SSE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1788 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 7.1 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,100,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,500,000× the energy of this one
  3. Around the size people start to feel M 3.0 130× the energy of this one
  4. This earthquake M 1.6 about 7.1 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 37.7675, -121.9737. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Alameda County, CA 14 km (9 mi) NNW of here earthquakes near Alameda County
Contra Costa County, CA 17 km (11 mi) S of here earthquakes near Contra Costa County
San Mateo County, CA 53 km (33 mi) NE of here earthquakes near San Mateo County
Solano County, CA 56 km (35 mi) S of here earthquakes near Solano County
San Joaquin County, CA 64 km (40 mi) WSW of here earthquakes near San Joaquin County
Santa Clara County, CA 66 km (41 mi) NNW of here earthquakes near Santa Clara 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. 1.5 2km NE of Union City, CA
  2. 1.7 11km NE of Milpitas, CA
  3. 2.6 2km SW of Colma, CA
  4. 1.5 10km ENE of Milpitas, CA
  5. 2.1 9km E of Alum Rock, CA
  6. 1.5 2km S of Alamo, CA
  7. 2.3 4km NE of Fairview, CA
  8. 1.8 5km NNE of Alum Rock, CA
  9. 1.6 2km NE of San Ramon, CA
  10. 1.9 1km NW of Danville, CA
  11. 1.7 1km WNW of Danville, CA
  12. 2.0 1km N of Pacifica, CA
  13. 1.6 6km E of Vallejo, CA
  14. 2.3 2km SW of Discovery Bay, CA
  15. 1.9 6km E of Vallejo, 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 4.5 on 2019-10-15 — it released about 21,000 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.