QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

31km ESE of Rio Dell, CA

· 22 km deep · released about 13 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Humboldt County 36 kmTrinity County 61 kmMendocino County 112 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
22 km below the surface
Felt
no reports yet
Nearest
Humboldt County, 36 km NNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2663 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 13 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 1,100,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 810,000× the energy of this one
  3. Around the size people start to feel M 3.0 72× the energy of this one
  4. This earthquake M 1.8 about 13 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 40.4055, -123.7620. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Humboldt County, CA 36 km (23 mi) SSE of here earthquakes near Humboldt County
Trinity County, CA 61 km (38 mi) WSW of here earthquakes near Trinity County
Mendocino County, CA 112 km (69 mi) NNW of here earthquakes near Mendocino County
Glenn County, CA 146 km (91 mi) NW of here earthquakes near Glenn County

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

Aftershocks so far

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

  1. 1.8 20km SSE of Rio Dell, CA
  2. 1.7 17km ENE of Hydesville, CA
  3. 1.9 9km ESE of Redway, CA
  4. 3.2 3km ESE of Petrolia, CA
  5. 1.7 12km ENE of Petrolia, CA
  6. 3.2 13km ESE of Blue Lake, CA
  7. 2.0 8km E of Hydesville, CA
  8. 3.0 27km WNW of Hayfork, CA
  9. 2.1 18km SE of Petrolia, CA
  10. 2.0 18km SE of Petrolia, CA
  11. 2.9 7km WSW of Rio Dell, CA
  12. 2.4 13km SSW of Rio Dell, CA
  13. 2.1 16km ENE of Hydesville, CA
  14. 1.8 11km SSW of Ferndale, CA
  15. 2.4 2km WSW of Ferndale, 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 4.8 on 2016-07-21 — it released about 38,000 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.