QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

5km W of San Francisco Zoo, CA

· 8.4 km deep · released about 14 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Marin County 38 kmSan Mateo County 40 kmSan Francisco County 41 kmContra Costa County 57 kmAlameda County 58 kmSolano County 80 kmNapa County 88 kmSonoma County 93 kmSanta Cruz County 95 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
8.4 km below the surface
Felt
no reports yet
Nearest
Marin County, 38 km NNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2307 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 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 5.7 760,000× the energy of this one
  3. Around the size people start to feel M 3.0 68× 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 37.7382, -122.5647. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Marin County, CA 38 km (24 mi) SSE of here earthquakes near Marin County
San Mateo County, CA 40 km (25 mi) NNW of here earthquakes near San Mateo County
San Francisco County, CA 41 km (26 mi) E of here earthquakes near San Francisco County
Contra Costa County, CA 57 km (36 mi) WSW of here earthquakes near Contra Costa County
Alameda County, CA 58 km (36 mi) W of here earthquakes near Alameda County
Solano County, CA 80 km (50 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

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

  1. 3.3 7km S of Muir Beach, CA
  2. 2.6 0km E of San Pablo, CA
  3. 1.9 2km NNE of San Leandro, 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. 2.1 4km ESE of Hayward, CA
  8. 1.6 2km N of El Cerrito, CA
  9. 1.8 3km ESE of Berkeley, CA
  10. 1.6 6km W of San Francisco Zoo, CA
  11. 1.6 3km ESE of Highlands-Baywood Park, CA
  12. 1.7 1km WSW of Pleasant Hill, CA
  13. 1.6 6km ESE of Santa Venetia, CA
  14. 1.8 5km NNE of Black Point-Green Point, CA
  15. 1.6 15km S of Half Moon Bay, 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 10,000 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.