QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

14km S of Bolinas, CA

· 7.2 km deep · released about 14 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N San Francisco County 29 kmMarin County 30 kmSan Mateo County 51 kmContra Costa County 68 kmAlameda County 71 kmSonoma County 84 kmSolano County 86 kmNapa County 87 kmSanta Cruz 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
7.2 km below the surface
Felt
1 report · strongest reported intensity III
Nearest
San Francisco County, 29 km WSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2449 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 1 person has reported feeling it to USGS.

How big was it?

This earthquake released about 14 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 5.7 790,000× the energy of this one
  3. Around the size people start to feel M 3.0 70× the energy of this one
  4. This earthquake M 1.8 about 14 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 37.7855, -122.7052. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
San Francisco County, CA 29 km (18 mi) ENE of here earthquakes near San Francisco County
Marin County, CA 30 km (19 mi) S of here earthquakes near Marin County
San Mateo County, CA 51 km (31 mi) NW of here earthquakes near San Mateo County
Contra Costa County, CA 68 km (42 mi) WSW of here earthquakes near Contra Costa County
Alameda County, CA 71 km (44 mi) WNW of here earthquakes near Alameda County
Sonoma County, CA 84 km (52 mi) SSE of here earthquakes near Sonoma County

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

Aftershocks so far

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

  1. 2.0 2km NNW of Kensington, CA
  2. 3.3 7km S of Muir Beach, CA
  3. 2.6 0km E of San Pablo, CA
  4. 1.7 2km E of Berkeley, CA
  5. 2.5 0km SE of Rollingwood, CA
  6. 1.6 0km SE of Rollingwood, CA
  7. 1.6 2km N of El Cerrito, CA
  8. 1.8 3km ESE of Berkeley, CA
  9. 1.6 6km W of San Francisco Zoo, CA
  10. 1.6 3km ESE of Highlands-Baywood Park, CA
  11. 1.6 6km ESE of Santa Venetia, CA
  12. 1.8 5km NNE of Black Point-Green Point, CA
  13. 2.4 2km E of Berkeley, CA
  14. 2.6 4km ESE of Berkeley, CA
  15. 2.1 4km 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 4.4 on 2018-01-04 — it released about 8,200 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.