QuakeIndex

Earthquake · reviewed by a seismologist

M 5.8mw

69km W of Petrolia, CA

· 3.2 km deep · released about 6.8 kilotons of TNT

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10 km30 km60 km120 km N Humboldt County 105 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 5.8 (mw)
Depth
3.2 km below the surface
Felt
2836 reports · strongest reported intensity VI
Measured shaking
intensity V (ShakeMap)
USGS impact alert
green
Tsunami
USGS flagged this event for tsunami evaluation. Follow tsunami.gov for official messages.
Nearest
Humboldt County, 105 km ENE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 279 days ago

This was a moderate earthquake. Shaking at this size can damage poorly built structures close to the epicentre. 2836 people have reported feeling it to USGS.

How big was it?

This earthquake released about 6.8 kilotons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 6.8 would have released about 32 times as much.

  1. Ridgecrest, California 2019 M 7.1 99× the energy of this one
  2. Loma Prieta, California 1989 M 6.9 50× the energy of this one
  3. Northridge, California 1994 M 6.7 25× the energy of this one
  4. This earthquake M 5.8 about 6.8 kilotons of TNT
  5. Magna, Utah 2020 M 5.7 this one released 1.3× more
  6. Around the size people start to feel M 3.0 this one released 14,000× 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 40.3917, -125.0937. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Humboldt County, CA 105 km (65 mi) WSW of here earthquakes near Humboldt 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. 2.6 63km W of Petrolia, CA
  2. 2.6 37km WNW of Petrolia, CA
  3. 2.5 27km W of Petrolia, CA
  4. 2.4 48km W of Petrolia, CA
  5. 1.9 35km W of Petrolia, CA
  6. 2.6 76km W of Petrolia, CA
  7. 2.5 31km W of Petrolia, CA
  8. 2.3 34km W of Petrolia, CA
  9. 1.8 27km W of Petrolia, CA
  10. 2.1 24km W of Petrolia, CA
  11. 2.4 37km W of Petrolia, CA
  12. 4.2 28km WNW of Petrolia, CA
  13. 2.6 35km WNW of Petrolia, CA
  14. 2.0 26km W of Petrolia, CA
  15. 1.7 23km 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.

For this area

The largest earthquake within 50 km in our catalogue was M 5.1 on 2017-07-29.

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

On USGS

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