QuakeIndex

Earthquake · reviewed by a seismologist

M 3.9mw

32 km SW of Scotia, California

· 8.2 km deep · released about 9 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Humboldt County 61 kmTrinity County 115 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 3.9 (mw)
Depth
8.2 km below the surface
Felt
13 reports · strongest reported intensity III
Measured shaking
intensity IV (ShakeMap)
Nearest
Humboldt County, 61 km NE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3414 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 13 people have reported feeling it to USGS.

How big was it?

This earthquake released about 9 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.8 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 19,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 840× the energy of this one
  3. Magna, Utah 2020 M 5.7 600× the energy of this one
  4. This earthquake M 3.9 about 9 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 19× 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 40.2905, -124.3952. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Humboldt County, CA 61 km (38 mi) SW of here earthquakes near Humboldt County
Trinity County, CA 115 km (72 mi) WSW of here earthquakes near Trinity County
Mendocino County, CA 125 km (78 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

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

  1. 1.8 43 km SW of Ferndale, California
  2. 2.6 9 km SW of Scotia, California
  3. 2.5 37 km SW of Ferndale, California
  4. 2.5 47 km WSW of Ferndale, California
  5. 2.0 35 km SSW of Ferndale, California
  6. 2.1 19 km WNW of Ferndale, California
  7. 1.6 10 km WSW of Scotia, California
  8. 1.7 46 km SW of Ferndale, California
  9. 2.1 11 km W of Ferndale, California
  10. 1.6 near the coast of Northern California
  11. 2.2 15 km W of Ferndale, California
  12. 2.3 30 km SW of Scotia, California
  13. 1.9 15 km SSW of Scotia, California
  14. 2.2 34 km SSW of Ferndale, California
  15. 1.7 32 km SSW 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.

For this area

The largest earthquake within 50 km in our catalogue was M 4.4 on 2016-01-02 — it released about 7.7 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.