QuakeIndex

Earthquake · reviewed by a seismologist

M 6.6mww

164 km W of Ferndale, California

Yes. A magnitude 6.6 earthquake was recorded 164 km W of Ferndale, California at 14:49 UTC on 2016-12-08, 8.4 km deep. 2,588 people have reported feeling it to USGS.

· 8.4 km deep · released about 120 kilotons of TNT

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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
2,588 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 1654 days ago

This was a strong earthquake. Damage is likely near the epicentre and it is felt over a wide area.

At this magnitude and depth, people at rest would likely notice it out to about 477 km (296 mi) from the epicentre. Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

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.

For this area

The largest earthquake within 50 km (31 mi) since our catalogue begins in 2016. The previous largest was M 5.6 on 2016-09-03.

Before 2016, the USGS record since 1900 lists no earthquake of M5 or more within 50 km.

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

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.

On USGS

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