QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

3km WSW of Muir Beach, CA

· 5.0 km deep · released about 15 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Marin County 24 kmSan Francisco County 39 kmSan Mateo County 54 kmContra Costa County 59 kmAlameda County 66 kmSolano County 75 kmNapa County 77 kmSonoma County 79 kmSanta Clara County 108 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 1.8 (md)
Depth
5.0 km below the surface
Felt
no reports yet
Nearest
Marin County, 24 km NNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2683 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 15 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 710,000× the energy of this one
  3. Around the size people start to feel M 3.0 63× the energy of this one
  4. This earthquake M 1.8 about 15 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 37.8575, -122.6180. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Marin County, CA 24 km (15 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 54 km (33 mi) NNW of here earthquakes near San Mateo County
Contra Costa County, CA 59 km (37 mi) W of here earthquakes near Contra Costa County
Alameda County, CA 66 km (41 mi) WNW of here earthquakes near Alameda County
Solano County, CA 75 km (47 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

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

  1. 2.3 2km ENE of El Cerrito, CA
  2. 2.1 1km NNE of Piedmont, CA
  3. 2.6 0km S of East Richmond Heights, CA
  4. 2.4 4km N of Lafayette, CA
  5. 1.7 4km N of Lafayette, CA
  6. 1.8 2km SE of Pacifica, CA
  7. 1.9 5km NNW of San Leandro, CA
  8. 1.8 14km S of Bolinas, CA
  9. 2.6 3km NW of Castro Valley, CA
  10. 2.2 2km WNW of Orinda, CA
  11. 2.1 2km NE of San Leandro, CA
  12. 1.7 7km NNE of Inverness, CA
  13. 2.3 2km ENE of San Leandro, CA
  14. 1.7 3km WSW of San Francisco Zoo, CA
  15. 1.7 3km SSW of American Canyon, 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 7,400 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.