QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7md

2km WNW of Concord, CA

· 16 km deep · released about 11 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 10 kmSolano County 33 kmAlameda County 38 kmMarin County 63 kmNapa County 64 kmSan Joaquin County 67 kmSan Mateo County 69 kmYolo County 79 kmSacramento County 80 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 1.7 (md)
Depth
16 km below the surface
Felt
2 reports · strongest reported intensity II
Nearest
Contra Costa County, 10 km SE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1444 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.

How big was it?

This earthquake released about 11 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,400,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 970,000× the energy of this one
  3. Around the size people start to feel M 3.0 86× the energy of this one
  4. This earthquake M 1.7 about 11 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 37.9782, -122.0358. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Contra Costa County, CA 10 km (6 mi) NW of here earthquakes near Contra Costa County
Solano County, CA 33 km (21 mi) SSW of here earthquakes near Solano County
Alameda County, CA 38 km (24 mi) NNW of here earthquakes near Alameda County
Marin County, CA 63 km (39 mi) E of here earthquakes near Marin County
Napa County, CA 64 km (40 mi) SSE of here earthquakes near Napa County
San Joaquin County, CA 67 km (42 mi) W 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. 1.5 2km NNE of Pleasant Hill, CA
  2. 1.7 7km SSW of Antioch, CA
  3. 2.1 4km S of Pittsburg, CA
  4. 1.8 9km SSW of Brentwood, CA
  5. 1.8 2km NE of Hayward, CA
  6. 1.6 2km NE of Hayward, CA
  7. 2.1 2km NNE of Hayward, CA
  8. 3.3 3km N of Union City, CA
  9. 2.9 2km NNE of San Leandro, CA
  10. 1.9 2km SSE of Pacheco, CA
  11. 3.6 1km ENE of El Cerrito, CA
  12. 1.6 3km E of Oakland, CA
  13. 1.5 4km S of Pittsburg, CA
  14. 1.7 5km E of Vallejo, CA
  15. 1.6 3km NW of Byron, 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 13,000 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.