QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

12km WNW of Boulder Creek, CA

· 11 km deep · released about 17 lb of TNT

10 km30 km60 km120 km N Santa Cruz County 28 kmSan Mateo County 29 kmSanta Clara County 50 kmAlameda County 60 kmContra Costa County 87 kmSan Francisco County 93 kmMarin County 107 kmStanislaus County 118 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
11 km below the surface
Felt
no reports yet
Nearest
Santa Cruz County, 28 km SE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2305 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 17 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 5.8 900,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 640,000× the energy of this one
  3. Around the size people start to feel M 3.0 57× the energy of this one
  4. This earthquake M 1.8 about 17 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 37.1733, -122.2477. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Santa Cruz County, CA 28 km (17 mi) NW of here earthquakes near Santa Cruz County
San Mateo County, CA 29 km (18 mi) SSE of here earthquakes near San Mateo County
Santa Clara County, CA 50 km (31 mi) W of here earthquakes near Santa Clara County
Alameda County, CA 60 km (38 mi) SSW of here earthquakes near Alameda County
Contra Costa County, CA 87 km (54 mi) SSW of here earthquakes near Contra Costa County
San Francisco County, CA 93 km (58 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

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

  1. 2.2 2km SW of Lexington Hills, CA
  2. 1.5 18km W of Boulder Creek, CA
  3. 1.7 14km SW of Santa Cruz, CA
  4. 1.9 0km SW of Los Gatos, CA
  5. 1.8 19km WNW of Bonny Doon, CA
  6. 2.1 4km WSW of Los Altos Hills, CA
  7. 2.6 8km WSW of Saratoga, CA
  8. 1.6 4km SSW of Newark, CA
  9. 2.2 19km WNW of Bonny Doon, CA
  10. 1.7 3km ESE of Bonny Doon, CA
  11. 1.9 6km E of Fremont, CA
  12. 3.0 22km W of Bonny Doon, CA
  13. 2.2 6km E of Alum Rock, CA
  14. 2.0 3km W of Portola Valley, CA
  15. 1.5 3km W of Portola Valley, 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.