QuakeIndex

Earthquake · reviewed by a seismologist

M 4.5mw

96 km WSW of Ferndale, California

· 18 km deep · released about 85 tons 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 4.5 (mw)
Depth
18 km below the surface
Felt
5 reports · strongest reported intensity III
Measured shaking
intensity II (ShakeMap)
USGS impact alert
green
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2321 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon. 5 people have reported feeling it to USGS.

How big was it?

This earthquake released about 85 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.5 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 2,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 89× the energy of this one
  3. Magna, Utah 2020 M 5.7 63× the energy of this one
  4. This earthquake M 4.5 about 85 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 180× 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 40.3955, -125.3782. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.7 72km WNW of Petrolia, CA
  2. 2.7 56km WNW of Petrolia, CA
  3. 3.4 106km W of Ferndale, CA
  4. 2.8 59km WNW of Petrolia, CA
  5. 2.6 65km W of Ferndale, CA
  6. 2.6 59km W of Petrolia, CA
  7. 4.5 90km W of Ferndale, CA
  8. 3.2 70km W of Ferndale, CA
  9. 2.8 88km W of Ferndale, CA
  10. 3.3 60km W of Petrolia, CA
  11. 1.9 52km WNW of Petrolia, CA
  12. 2.5 48km WNW of Petrolia, CA
  13. 2.8 72km W of Petrolia, CA
  14. 2.9 120km W of Petrolia, CA
  15. 2.6 68km W of Petrolia, 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.