QuakeIndex

Earthquake · reviewed by a seismologist

M 3.4mw

2km NE of Pacheco, CA

· 17 km deep · released about 1.7 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 13 kmSolano County 32 kmAlameda County 41 kmMarin County 60 kmNapa County 61 kmSan Joaquin County 69 kmSan Mateo County 70 kmYolo County 77 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 3.4 (mw)
Depth
17 km below the surface
Felt
767 reports · strongest reported intensity III
Measured shaking
intensity IV (ShakeMap)
Nearest
Contra Costa County, 13 km SE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 243 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 767 people have reported feeling it to USGS.

How big was it?

This earthquake released about 1.7 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.4 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 99,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 4,400× the energy of this one
  3. Magna, Utah 2020 M 5.7 3,100× the energy of this one
  4. This earthquake M 3.4 about 1.7 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 3.6× more

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 37.9952, -122.0605. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Contra Costa County, CA 13 km (8 mi) NW of here earthquakes near Contra Costa County
Solano County, CA 32 km (20 mi) SSW of here earthquakes near Solano County
Alameda County, CA 41 km (25 mi) NNW of here earthquakes near Alameda County
Marin County, CA 60 km (38 mi) E of here earthquakes near Marin County
Napa County, CA 61 km (38 mi) SSE of here earthquakes near Napa County
San Joaquin County, CA 69 km (43 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

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

  1. 1.7 4km ESE of Oakland, CA
  2. 1.9 12km NW of Rio Vista, CA
  3. 2.4 4km NNW of Green Valley, CA
  4. 1.6 2km E of Berkeley, CA
  5. 1.6 3km ENE of Pittsburg, CA
  6. 2.0 3km SSW of Alameda, CA
  7. 2.5 3km N of San Leandro, CA
  8. 2.0 5km SSE of Pittsburg, CA
  9. 1.6 4km ESE of Moraga, CA
  10. 1.5 3km NE of Alamo, CA
  11. 1.8 2km NE of San Ramon, CA
  12. 1.8 2km NE of San Ramon, CA
  13. 2.0 9km N of Pittsburg, CA
  14. 1.8 11km N of Bay Point, CA
  15. 1.5 2km SW of Clayton, 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 4.4 on 2018-01-04 — it released about 33 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.