QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

32km WNW of Bonny Doon, CA

· 7.8 km deep · released about 15 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N San Mateo County 35 kmSanta Cruz County 45 kmSanta Clara County 73 kmAlameda County 79 kmSan Francisco County 83 kmContra Costa County 102 kmMarin County 106 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
7.8 km below the surface
Felt
no reports yet
Nearest
San Mateo County, 35 km NNE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2602 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 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 37.1135, -122.5017. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
San Mateo County, CA 35 km (22 mi) SSW of here earthquakes near San Mateo County
Santa Cruz County, CA 45 km (28 mi) WNW of here earthquakes near Santa Cruz County
Santa Clara County, CA 73 km (45 mi) W of here earthquakes near Santa Clara County
Alameda County, CA 79 km (49 mi) SW of here earthquakes near Alameda County
San Francisco County, CA 83 km (51 mi) SE of here earthquakes near San Francisco County
Contra Costa County, CA 102 km (63 mi) SSW of here earthquakes near Contra Costa County

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

Aftershocks so far

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

  1. 1.6 11km WSW of Saratoga, CA
  2. 1.6 7km SW of Los Altos Hills, CA
  3. 1.7 11km W of Bonny Doon, CA
  4. 1.5 5km WSW of Lexington Hills, CA
  5. 2.2 12km WSW of Saratoga, CA
  6. 1.9 3km S of Los Altos Hills, CA
  7. 2.2 2km S of Los Altos Hills, CA
  8. 1.7 3km S of Los Altos Hills, CA
  9. 2.1 2km SSW of Los Altos Hills, CA
  10. 2.8 3km S of Los Altos Hills, CA
  11. 1.8 2km S of Los Altos Hills, CA
  12. 1.6 3km ESE of Highlands-Baywood Park, CA
  13. 1.6 15km S of Half Moon Bay, CA
  14. 1.8 8km SSW of Loyola, CA
  15. 2.7 7km N of Boulder Creek, 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.