QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6md

4km SW of San Ramon, CA

· 7.5 km deep · released about 7.3 lb of TNT

10 km30 km60 km120 km N Alameda County 15 kmContra Costa County 19 kmSan Mateo County 49 kmSolano County 57 kmSanta Clara County 66 kmSan Joaquin County 68 kmMarin County 72 kmSanta Cruz County 83 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
7.5 km below the surface
Felt
1 report · strongest reported intensity I
Nearest
Alameda County, 15 km SE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1615 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 1 person has reported feeling it to USGS.

How big was it?

This earthquake released about 7.3 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 7.3 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 37.7585, -122.0162. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Alameda County, CA 15 km (10 mi) NW of here earthquakes near Alameda County
Contra Costa County, CA 19 km (12 mi) SSW of here earthquakes near Contra Costa County
San Mateo County, CA 49 km (31 mi) NE of here earthquakes near San Mateo County
Solano County, CA 57 km (35 mi) S of here earthquakes near Solano County
Santa Clara County, CA 66 km (41 mi) NNW of here earthquakes near Santa Clara County
San Joaquin County, CA 68 km (42 mi) WSW 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

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

  1. 1.7 3km ESE of Pacifica, CA
  2. 1.9 3km ESE of Pacifica, CA
  3. 1.8 3km ESE of Pacifica, CA
  4. 1.7 1km W of Pacifica, CA
  5. 2.2 1km WSW of Pacifica, CA
  6. 2.5 4km SSE of Rodeo, CA
  7. 1.8 2km SSE of Alamo, CA
  8. 1.9 9km NE of Milpitas, CA
  9. 2.2 3km W of Orinda, CA
  10. 2.3 3km W of Orinda, CA
  11. 1.6 8km SSE of Suisun City, CA
  12. 1.6 3km E of Oakland, CA
  13. 1.5 7km ESE of Fremont, CA
  14. 1.6 5km E of Vallejo, CA
  15. 1.5 9km NNE 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 4.5 on 2019-10-15 — it released about 20,000 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.