QuakeIndex

Earthquake · reviewed by a seismologist

M 2.9md

2 km NE of Pacifica, California

· 7.7 km deep · released about 590 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N San Mateo County 25 kmAlameda County 49 kmSan Francisco County 51 kmMarin County 53 kmContra Costa County 56 kmSanta Cruz County 80 kmSanta Clara County 83 kmSolano County 85 kmNapa County 99 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 2.9 (md)
Depth
7.7 km below the surface
Felt
723 reports · strongest reported intensity III
Nearest
San Mateo County, 25 km SSE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2550 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 723 people have reported feeling it to USGS.

How big was it?

This earthquake released about 590 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 26,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 18,000× the energy of this one
  3. Around the size people start to feel M 3.0 1.6× the energy of this one
  4. This earthquake M 2.9 about 590 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 37.6282, -122.4713. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
San Mateo County, CA 25 km (16 mi) NNW of here earthquakes near San Mateo County
Alameda County, CA 49 km (31 mi) W of here earthquakes near Alameda County
San Francisco County, CA 51 km (31 mi) ESE of here earthquakes near San Francisco County
Marin County, CA 53 km (33 mi) SSE of here earthquakes near Marin County
Contra Costa County, CA 56 km (35 mi) SW of here earthquakes near Contra Costa County
Santa Cruz County, CA 80 km (50 mi) NNW of here earthquakes near Santa Cruz County

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

Aftershocks so far

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

  1. 1.6 4 km SW of Broadmoor, California
  2. 1.8 4 km SW of Broadmoor, California
  3. 1.5 2 km SSW of Broadmoor, California
  4. 1.7 2 km ENE of Pacifica, California
  5. 1.9 1 km W of Diablo, California
  6. 1.6 1 km W of Diablo, California
  7. 1.7 1 km W of Diablo, California
  8. 2.0 5 km WSW of Martinez, California
  9. 1.7 1 km N of Pacifica, California
  10. 2.2 1 km ENE of Pacifica, California
  11. 1.6 1 km ENE of Pacifica, California
  12. 2.5 3 km NNW of Piedmont, California
  13. 2.4 7 km S of Muir Beach, California
  14. 1.9 3 km S of Loyola, California
  15. 1.7 5 km SW of Alamo, California

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.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.