QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

5km NNE of Black Point-Green Point, CA

· 4.2 km deep · released about 13 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Marin County 26 kmNapa County 42 kmSolano County 49 kmContra Costa County 53 kmSonoma County 57 kmSan Francisco County 68 kmAlameda County 75 kmYolo County 77 kmSan Mateo County 83 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
4.2 km below the surface
Felt
4 reports · strongest reported intensity II
Nearest
Marin County, 26 km WSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2158 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 4 people have reported feeling it to USGS.

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 1,200,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 840,000× the energy of this one
  3. Around the size people start to feel M 3.0 75× 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 38.1532, -122.4825. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Marin County, CA 26 km (16 mi) ENE of here earthquakes near Marin County
Napa County, CA 42 km (26 mi) SSW of here earthquakes near Napa County
Solano County, CA 49 km (31 mi) WSW of here earthquakes near Solano County
Contra Costa County, CA 53 km (33 mi) WNW of here earthquakes near Contra Costa County
Sonoma County, CA 57 km (35 mi) SE of here earthquakes near Sonoma County
San Francisco County, CA 68 km (42 mi) NE of here earthquakes near San Francisco County

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

Aftershocks so far

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

  1. 1.6 7km ENE of Rohnert Park, CA
  2. 2.0 7km ENE of Rohnert Park, CA
  3. 1.7 7km ENE of Rohnert Park, CA
  4. 2.5 7km ENE of Rohnert Park, CA
  5. 1.9 2km NW of Orinda, CA
  6. 1.7 9km NW of San Francisco Zoo, CA
  7. 3.0 1km W of Concord, CA
  8. 1.6 6km E of Santa Rosa, CA
  9. 2.0 6km WNW of San Francisco Zoo, CA
  10. 1.6 3km ENE of Walnut Creek, CA
  11. 1.8 7km NW of San Francisco Zoo, CA
  12. 2.3 7km NW of San Francisco Zoo, CA
  13. 2.7 3km NNW of Santa Rosa, CA
  14. 2.1 2km WNW of Concord, CA
  15. 3.6 2km W of Concord, 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 12,000 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.