QuakeIndex

Earthquake · reviewed by a seismologist

M 6.6mww

164 km W of Ferndale, California

· 8.4 km deep · released about 120 kilotons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N
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 6.6 (mww)
Depth
8.4 km below the surface
Felt
2588 reports · strongest reported intensity V
Measured shaking
intensity IV (ShakeMap)
USGS impact alert
green
Tsunami
USGS flagged this event for tsunami evaluation. Follow tsunami.gov for official messages.
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1608 days ago

This was a strong earthquake. Damage is likely near the epicentre and it is felt over a wide area. 2588 people have reported feeling it to USGS.

How big was it?

This earthquake released about 120 kilotons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 7.6 would have released about 32 times as much.

  1. Ridgecrest, California 2019 M 7.1 5.6× the energy of this one
  2. Loma Prieta, California 1989 M 6.9 2.8× the energy of this one
  3. Northridge, California 1994 M 6.7 1.4× the energy of this one
  4. This earthquake M 6.6 about 120 kilotons of TNT
  5. Mineral, Virginia 2011 M 5.8 this one released 16× more
  6. Magna, Utah 2020 M 5.7 this one released 22× 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 40.4535, -126.1936. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 3.0 182 km W of Ferndale, California
  2. 2.8 204 km W of Ferndale, California
  3. 2.6 off the coast of Northern California
  4. 2.8 off the coast of Northern California
  5. 2.7 140 km W of Ferndale, California
  6. 3.0 160 km W of Ferndale, California
  7. 3.1 182 km W of Ferndale, California
  8. 3.2 175 km W of Ferndale, California
  9. 2.6 165 km W of Ferndale, California
  10. 3.2 135km W of Petrolia, CA
  11. 3.0 170 km W of Ferndale, California
  12. 2.8 189 km W of Ferndale, California
  13. 2.9 186 km W of Ferndale, California
  14. 3.2 off the coast of Northern California
  15. 2.7 143 km W of Ferndale, California

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 5.6 on 2016-09-03.

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

On USGS

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