QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

4km SSE of Point Reyes Station, CA

· 3.8 km deep · released about 13 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Marin County 5 kmSan Francisco County 40 kmSonoma County 55 kmNapa County 66 kmContra Costa County 75 kmSan Mateo County 79 kmSolano County 79 kmAlameda County 89 kmYolo County 106 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
3.8 km below the surface
Felt
no reports yet
Nearest
Marin County, 5 km ENE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2755 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 13 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 1,100,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 810,000× the energy of this one
  3. Around the size people start to feel M 3.0 72× the energy of this one
  4. This earthquake M 1.8 about 13 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 38.0405, -122.7973. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Marin County, CA 5 km (3 mi) WSW of here earthquakes near Marin County
San Francisco County, CA 40 km (25 mi) NNE of here earthquakes near San Francisco County
Sonoma County, CA 55 km (34 mi) SSE of here earthquakes near Sonoma County
Napa County, CA 66 km (41 mi) SW of here earthquakes near Napa County
Contra Costa County, CA 75 km (47 mi) W of here earthquakes near Contra Costa County
San Mateo County, CA 79 km (49 mi) NNW of here earthquakes near San Mateo County

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

Aftershocks so far

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

  1. 1.9 4km SSW of Vallejo, CA
  2. 1.8 4km SSW of Bodega Bay, CA
  3. 1.8 6km WSW of Colma, CA
  4. 1.9 6km WSW of Colma, CA
  5. 1.6 6km WSW of Colma, CA
  6. 3.5 5km WSW of Colma, CA
  7. 1.8 1km E of El Cerrito, CA
  8. 1.7 2km SSE of American Canyon, CA
  9. 2.6 6km WSW of San Francisco Zoo, CA
  10. 2.5 6km WSW of San Francisco Zoo, CA
  11. 1.6 4km ESE of Kenwood, CA
  12. 2.2 6km WSW of Yountville, CA
  13. 1.5 2km NW of Roseland, CA
  14. 2.2 3km WSW of American Canyon, CA
  15. 2.1 2km WNW of Vallejo, 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.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.