QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

27 km SSW of Ferndale, California

· 17 km deep · released about 17 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Humboldt County 56 kmTrinity County 113 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 1.8 (md)
Depth
17 km below the surface
Felt
no reports yet
Nearest
Humboldt County, 56 km NE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3321 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

How big was it?

This earthquake released about 17 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 900,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 640,000× the energy of this one
  3. Around the size people start to feel M 3.0 57× the energy of this one
  4. This earthquake M 1.8 about 17 lb of TNT

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 40.3490, -124.3895. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Humboldt County, CA 56 km (35 mi) SW of here earthquakes near Humboldt County
Trinity County, CA 113 km (70 mi) WSW of here earthquakes near Trinity County
Mendocino County, CA 130 km (81 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

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

  1. 1.8 4km WSW of Rio Dell, CA
  2. 2.5 31km W of Petrolia, CA
  3. 2.1 20km W of Petrolia, CA
  4. 1.9 18km W of Petrolia, CA
  5. 3.0 12km WSW of Petrolia, CA
  6. 3.8 20km WSW of Petrolia, CA
  7. 2.3 9km WSW of Petrolia, CA
  8. 3.9 28km WNW of Petrolia, CA
  9. 2.8 5km NE of Hydesville, CA
  10. 2.8 4km SSW of Humboldt Hill, CA
  11. 2.3 19km W of Petrolia, CA
  12. 2.1 5km SW of Humboldt Hill, CA
  13. 2.5 5km WSW of Humboldt Hill, CA
  14. 1.8 15km ESE of Hydesville, CA
  15. 2.6 34km WNW 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 4.4 on 2016-01-02 — it released about 8,200 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.