QuakeIndex

Earthquake · reviewed by a seismologist

M 3.1ml

23 km W of Petrolia, CA

· 15 km deep · released about 1,400 lb of TNT

10 km30 km60 km120 km N Humboldt County 70 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 3.1 (ml)
Depth
15 km below the surface
Felt
16 reports · strongest reported intensity III
Nearest
Humboldt County, 70 km NE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1065 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 16 people have reported feeling it to USGS.

How big was it?

This earthquake released about 1,400 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.1 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 240,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 11,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 7,700× the energy of this one
  4. This earthquake M 3.1 about 1,400 lb of TNT
  5. Around the size people start to feel M 3.0 this one released 1.5× 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 40.2937, -124.5532. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Humboldt County, CA 70 km (44 mi) SW of here earthquakes near Humboldt County
Mendocino County, CA 135 km (84 mi) NW of here earthquakes near Mendocino County

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

Aftershocks so far

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

  1. 2.2 13 km W of Petrolia, CA
  2. 1.8 12 km WSW of Ferndale, CA
  3. 2.5 32 km WNW of Petrolia, CA
  4. 2.4 16 km WSW of Petrolia, CA
  5. 1.7 18 km W of Petrolia, CA
  6. 2.3 21 km WSW of Petrolia, CA
  7. 3.0 55 km W of Petrolia, CA
  8. 1.7 15 km E of Petrolia, CA
  9. 2.6 19 km WSW of Ferndale, CA
  10. 2.8 19 km E of Petrolia, CA
  11. 3.0 19 km E of Petrolia, CA
  12. 2.1 18 km SSE of Rio Dell, CA
  13. 4.8 20 km E of Petrolia, CA
  14. 1.7 10 km W of Petrolia, CA
  15. 1.7 4 km ESE of Fortuna, 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 6.4 on 2022-12-20 — it released about 86,000 times the energy of this one.

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

On USGS

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