QuakeIndex

Earthquake · reviewed by a seismologist

M 6.4mw

15km WSW of Ferndale, CA

· 18 km deep · released about 60 kilotons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Humboldt County 47 kmTrinity 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 6.4 (mw)
Depth
18 km below the surface
Felt
5910 reports · strongest reported intensity VII
Measured shaking
intensity VIII (ShakeMap)
USGS impact alert
orange
Tsunami
USGS flagged this event for tsunami evaluation. Follow tsunami.gov for official messages.
Nearest
Humboldt County, 47 km ENE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 264 days ago

This was a strong earthquake. Damage is likely near the epicentre and it is felt over a wide area. 5910 people have reported feeling it to USGS.

How big was it?

This earthquake released about 60 kilotons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 7.4 would have released about 32 times as much.

  1. Ridgecrest, California 2019 M 7.1 11× the energy of this one
  2. Loma Prieta, California 1989 M 6.9 5.6× the energy of this one
  3. Northridge, California 1994 M 6.7 2.8× the energy of this one
  4. This earthquake M 6.4 about 60 kilotons of TNT
  5. Mineral, Virginia 2011 M 5.8 this one released 7.9× more
  6. Magna, Utah 2020 M 5.7 this one released 11× more

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 40.5250, -124.4230. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Humboldt County, CA 47 km (29 mi) WSW of here earthquakes near Humboldt County
Trinity County, CA 111 km (69 mi) W of here earthquakes near Trinity County

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

Aftershocks so far

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

  1. 2.1 12km WSW of Ferndale, CA
  2. 1.8 16km WSW of Ferndale, CA
  3. 2.1 13km WSW of Ferndale, CA
  4. 2.1 16km WSW of Ferndale, CA
  5. 2.4 4km SE of Fortuna, CA
  6. 2.5 21km WSW of Ferndale, CA
  7. 2.0 5km SSW of Ferndale, CA
  8. 3.0 5km E of Fortuna, CA
  9. 2.6 6km SW of Ferndale, CA
  10. 2.1 5km ESE of Ferndale, CA
  11. 2.2 5km SE of Ferndale, CA
  12. 2.5 7km SW of Ferndale, CA
  13. 2.2 21km SW of Ferndale, CA
  14. 1.7 2km SW of Fortuna, CA
  15. 2.4 5km N of Hydesville, 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 6.2 on 2021-12-20.

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

On USGS

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