QuakeIndex

Earthquake · reviewed by a seismologist

M 3.3ml

7km S of Muir Beach, CA

· 13 km deep · released about 1.5 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Marin County 31 kmSan Francisco County 39 kmSan Mateo County 47 kmContra Costa County 58 kmAlameda County 62 kmSolano County 77 kmNapa County 82 kmSonoma County 86 kmSanta Cruz 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 3.3 (ml)
Depth
13 km below the surface
Felt
3865 reports · strongest reported intensity IV
Measured shaking
intensity IV (ShakeMap)
Nearest
Marin County, 31 km NNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 653 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 3865 people have reported feeling it to USGS.

How big was it?

This earthquake released about 1.5 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.3 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 110,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 5,100× the energy of this one
  3. Magna, Utah 2020 M 5.7 3,600× the energy of this one
  4. This earthquake M 3.3 about 1.5 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 3.1× 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 37.7995, -122.5937. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Marin County, CA 31 km (19 mi) SSE of here earthquakes near Marin County
San Francisco County, CA 39 km (24 mi) ENE of here earthquakes near San Francisco County
San Mateo County, CA 47 km (29 mi) NNW of here earthquakes near San Mateo County
Contra Costa County, CA 58 km (36 mi) WSW of here earthquakes near Contra Costa County
Alameda County, CA 62 km (39 mi) WNW of here earthquakes near Alameda County
Solano County, CA 77 km (48 mi) SW of here earthquakes near Solano County

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

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

  1. 1.6 1km NE of Berkeley, CA
  2. 2.0 1km NNW of Pleasant Hill, CA
  3. 1.5 2km ESE of Berkeley, CA
  4. 1.5 4km E of Moraga, CA
  5. 1.8 7km S of Muir Beach, CA
  6. 1.9 4km SSW of Colma, CA
  7. 1.7 2km E of Berkeley, CA
  8. 2.1 8km S of Muir Beach, CA
  9. 1.6 8km S of Muir Beach, CA
  10. 1.6 3km NNW of Piedmont, CA
  11. 2.1 2km ENE of Berkeley, CA
  12. 1.7 3km WNW of Castro Valley, CA
  13. 1.9 1km NNW of Crockett, CA
  14. 3.9 3km N of San Lorenzo, CA
  15. 1.8 2km ESE of Berkeley, 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 50 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.