QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

4 km WNW of La Honda, California

· 6.4 km deep · released about 14 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N San Mateo County 10 kmSanta Cruz County 45 kmAlameda County 50 kmSanta Clara County 57 kmContra Costa County 73 kmSan Francisco County 77 kmMarin County 88 kmSolano County 109 kmSan Joaquin County 114 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
6.4 km below the surface
Felt
no reports yet
Nearest
San Mateo County, 10 km NNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3223 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 37.3307, -122.3230. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
San Mateo County, CA 10 km (6 mi) SSE of here earthquakes near San Mateo County
Santa Cruz County, CA 45 km (28 mi) NW of here earthquakes near Santa Cruz County
Alameda County, CA 50 km (31 mi) SW of here earthquakes near Alameda County
Santa Clara County, CA 57 km (36 mi) WNW of here earthquakes near Santa Clara County
Contra Costa County, CA 73 km (45 mi) SSW of here earthquakes near Contra Costa County
San Francisco County, CA 77 km (48 mi) SE 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 8km N of Boulder Creek, CA
  2. 2.0 3km N of San Leandro, CA
  3. 1.6 3km NE of Fremont, CA
  4. 1.9 4km SSW of Loyola, CA
  5. 1.8 5km SSW of Loyola, CA
  6. 2.8 6km SSW of Loyola, CA
  7. 1.8 5km SSW of Loyola, CA
  8. 1.5 9km ENE of Milpitas, CA
  9. 1.8 21km WNW of Bonny Doon, CA
  10. 1.7 4km ESE of Union City, CA
  11. 1.5 4km NNW of Foster City, CA
  12. 1.9 3km WSW of Portola Valley, CA
  13. 1.8 5km SSE of Portola Valley, CA
  14. 1.9 9km NNE of Alum Rock, CA
  15. 1.7 9km NE of Milpitas, 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.

On USGS

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