QuakeIndex

quarry blast · reviewed by a seismologist

M 1.8md

6km E of San Rafael, CA

· -0.0 km deep · released about 15 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Marin County 26 kmContra Costa County 45 kmSolano County 56 kmSan Francisco County 57 kmNapa County 60 kmAlameda County 61 kmSan Mateo County 63 kmSonoma County 73 kmYolo County 92 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
-0.0 km below the surface
Felt
no reports yet
Nearest
Marin County, 26 km WNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1250 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

USGS catalogues this as quarry blast, not an earthquake.

How big was it?

This earthquake released about 15 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 1,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 730,000× the energy of this one
  3. Around the size people start to feel M 3.0 65× the energy of this one
  4. This earthquake M 1.8 about 15 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 37.9762, -122.4633. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Marin County, CA 26 km (16 mi) ESE of here earthquakes near Marin County
Contra Costa County, CA 45 km (28 mi) W of here earthquakes near Contra Costa County
Solano County, CA 56 km (35 mi) SW of here earthquakes near Solano County
San Francisco County, CA 57 km (35 mi) ENE of here earthquakes near San Francisco County
Napa County, CA 60 km (37 mi) SSW of here earthquakes near Napa County
Alameda County, CA 61 km (38 mi) NW of here earthquakes near Alameda County

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

Aftershocks so far

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

  1. 1.6 0 km WSW of Diablo, CA
  2. 2.5 3 km NNW of Piedmont, CA
  3. 1.8 6 km ESE of Santa Venetia, CA
  4. 1.5 6 km NNE of Orinda, CA
  5. 2.1 10 km WSW of San Lorenzo, CA
  6. 1.7 2 km ENE of San Leandro, CA
  7. 2.0 7 km NW of San Francisco Zoo, CA
  8. 1.9 3 km ESE of South San Francisco, CA
  9. 2.0 1 km E of Pacifica, CA
  10. 2.3 1 km E of Pacifica, CA
  11. 2.2 1 km NW of Green Valley, CA
  12. 2.4 4 km W of Glen Ellen, CA
  13. 1.6 7 km WNW of Yountville, CA
  14. 1.8 3 km WNW of Boyes Hot Springs, CA
  15. 1.5 4 km ESE of Pacifica, 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.