QuakeIndex

Earthquake · reviewed by a seismologist

M 3.3ml

7km ENE of Petrolia, CA

· 28 km deep · released about 1.1 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Humboldt County 46 kmTrinity County 99 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 3.3 (ml)
Depth
28 km below the surface
Felt
7 reports · strongest reported intensity II
Nearest
Humboldt County, 46 km NNE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2098 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 7 people have reported feeling it to USGS.

How big was it?

This earthquake released about 1.1 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.3 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 150,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 6,700× the energy of this one
  3. Magna, Utah 2020 M 5.7 4,700× the energy of this one
  4. This earthquake M 3.3 about 1.1 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 2.4× 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 40.3537, -124.2145. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Humboldt County, CA 46 km (29 mi) SSW of here earthquakes near Humboldt County
Trinity County, CA 99 km (61 mi) WSW of here earthquakes near Trinity County
Mendocino County, CA 122 km (76 mi) NNW of here earthquakes near Mendocino County

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

Aftershocks so far

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

  1. 2.6 9km WSW of Petrolia, CA
  2. 2.7 18km WSW of Petrolia, CA
  3. 3.2 12km WSW of Petrolia, CA
  4. 2.9 7km WNW of Petrolia, CA
  5. 2.8 13km W of Petrolia, CA
  6. 2.6 27km W of Petrolia, CA
  7. 2.3 12km WSW of Rio Dell, CA
  8. 2.1 22km NW of Petrolia, CA
  9. 2.1 18km WSW of Petrolia, CA
  10. 1.9 2km NW of Redway, CA
  11. 2.0 4km WNW of Petrolia, CA
  12. 1.9 14km SE of Petrolia, CA
  13. 2.3 11km SW of Petrolia, CA
  14. 2.9 12km SW of Petrolia, CA
  15. 2.1 21km NW 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 5.6 on 2019-06-23 — it released about 3,100 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.