QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

7 km ENE of Black Point-Green Point, CA

· 7.2 km deep · released about 17 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Marin County 28 kmNapa County 42 kmSolano County 46 kmContra Costa County 50 kmSonoma County 59 kmSan Francisco County 69 kmAlameda County 73 kmYolo County 76 kmSan Mateo County 81 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 II
Nearest
Marin County, 28 km WSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 612 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 17 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 5.8 870,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 620,000× the energy of this one
  3. Around the size people start to feel M 3.0 55× the energy of this one
  4. This earthquake M 1.8 about 17 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 38.1448, -122.4467. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Marin County, CA 28 km (18 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 46 km (29 mi) WSW of here earthquakes near Solano County
Contra Costa County, CA 50 km (31 mi) WNW of here earthquakes near Contra Costa County
Sonoma County, CA 59 km (37 mi) SE of here earthquakes near Sonoma County
San Francisco County, CA 69 km (43 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

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

  1. 1.8 5 km WSW of Clayton, CA
  2. 1.8 3 km ENE of Oakland, CA
  3. 1.5 6 km SSE of Napa, CA
  4. 2.2 4 km E of Saint Helena, CA
  5. 1.5 0 km SSE of San Pablo, CA
  6. 1.6 5 km E of Vallejo, CA
  7. 2.1 12 km NNE of Bay Point, CA
  8. 2.3 0 km SSW of Concord, CA
  9. 1.7 4 km W of Alamo, CA
  10. 2.5 4 km W of Alamo, CA
  11. 2.5 4 km W of Alamo, CA
  12. 1.5 3 km WSW of San Francisco Zoo, CA
  13. 2.4 5 km WSW of San Francisco Zoo, CA
  14. 1.6 1 km S of Pacheco, CA
  15. 1.7 0 km NNE of East Richmond Heights, 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 8,500 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.