QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

21km WNW of Bonny Doon, CA

· 6.4 km deep · released about 13 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Santa Cruz County 34 kmSan Mateo County 36 kmSanta Clara County 62 kmAlameda County 74 kmSan Francisco County 91 kmContra Costa County 99 kmMarin County 111 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
Santa Cruz County, 34 km ESE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3050 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 13 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 5.7 810,000× the energy of this one
  3. Around the size people start to feel M 3.0 72× the energy of this one
  4. This earthquake M 1.8 about 13 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 37.0952, -122.3730. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Santa Cruz County, CA 34 km (21 mi) WNW of here earthquakes near Santa Cruz County
San Mateo County, CA 36 km (22 mi) S of here earthquakes near San Mateo County
Santa Clara County, CA 62 km (39 mi) WSW of here earthquakes near Santa Clara County
Alameda County, CA 74 km (46 mi) SSW of here earthquakes near Alameda County
San Francisco County, CA 91 km (57 mi) SE of here earthquakes near San Francisco County
Contra Costa County, CA 99 km (61 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

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

  1. 2.1 11km SW of Bonny Doon, CA
  2. 1.6 10km N of Boulder Creek, CA
  3. 2.4 21km NW of Pacific Grove, CA
  4. 1.6 4km SE of Portola Valley, CA
  5. 2.3 2km E of Bonny Doon, CA
  6. 1.6 20km WNW of Boulder Creek, CA
  7. 1.8 21km W of Boulder Creek, CA
  8. 2.5 20km WNW of Boulder Creek, CA
  9. 2.8 21km WNW of Boulder Creek, CA
  10. 1.9 20km WNW of Boulder Creek, CA
  11. 2.2 5km WSW of Cupertino, CA
  12. 1.9 3km S of Loyola, CA
  13. 1.5 3km S of Loyola, CA
  14. 1.8 8km SSE of Portola Valley, CA
  15. 2.1 3km SW of Monte Sereno, 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.