QuakeIndex

Earthquake · reviewed by a seismologist

M 2.7md

7km N of Boulder Creek, CA

· 9.4 km deep · released about 360 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Santa Cruz County 22 kmSan Mateo County 34 kmSanta Clara County 38 kmAlameda County 54 kmContra Costa County 83 kmSan Francisco County 101 kmStanislaus County 107 kmMarin County 111 kmSan Joaquin County 112 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 2.7 (md)
Depth
9.4 km below the surface
Felt
201 reports · strongest reported intensity IV
Nearest
Santa Cruz County, 22 km SSE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2079 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 201 people have reported feeling it to USGS.

How big was it?

This earthquake released about 360 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 42,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 30,000× the energy of this one
  3. Around the size people start to feel M 3.0 2.6× the energy of this one
  4. This earthquake M 2.7 about 360 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 37.1867, -122.1197. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Santa Cruz County, CA 22 km (14 mi) NNW of here earthquakes near Santa Cruz County
San Mateo County, CA 34 km (21 mi) SE of here earthquakes near San Mateo County
Santa Clara County, CA 38 km (24 mi) W of here earthquakes near Santa Clara County
Alameda County, CA 54 km (34 mi) SSW of here earthquakes near Alameda County
Contra Costa County, CA 83 km (51 mi) S of here earthquakes near Contra Costa County
San Francisco County, CA 101 km (62 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

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

  1. 1.8 15km NNE of Morgan Hill, CA
  2. 1.7 3km S of Los Altos Hills, CA
  3. 1.6 3km ESE of Union City, CA
  4. 1.7 16km E of Seven Trees, CA
  5. 1.9 16km E of Seven Trees, CA
  6. 3.0 8km NE of Alum Rock, CA
  7. 1.8 9km ENE of Milpitas, CA
  8. 2.1 9km ENE of Milpitas, 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. 2.6 16km E of Seven Trees, CA
  13. 1.5 8km ENE of Alum Rock, CA
  14. 1.6 9km NE of Milpitas, CA
  15. 1.7 7km N of Day 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.

For this area

The largest earthquake within 50 km in our catalogue was M 4.1 on 2017-10-10 — it released about 110 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

On USGS

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