QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

5km SSE of Shelter Cove, CA

· 7.2 km deep · released about 16 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Humboldt County 81 kmMendocino County 81 kmTrinity County 108 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
7.2 km below the surface
Felt
no reports yet
Nearest
Humboldt County, 81 km N
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1541 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 16 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 5.8 930,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 660,000× the energy of this one
  3. Around the size people start to feel M 3.0 59× the energy of this one
  4. This earthquake M 1.8 about 16 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 39.9880, -124.0520. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Humboldt County, CA 81 km (50 mi) S of here earthquakes near Humboldt County
Mendocino County, CA 81 km (50 mi) NW of here earthquakes near Mendocino County
Trinity County, CA 108 km (67 mi) SW of here earthquakes near Trinity County
Lake County, CA 149 km (92 mi) NW of here earthquakes near Lake County

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

Aftershocks so far

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

  1. 1.5 16km NNW of Laytonville, CA
  2. 2.8 12km WSW of Petrolia, CA
  3. 3.7 7km WSW of Petrolia, CA
  4. 2.7 7km N of Petrolia, CA
  5. 2.3 10km WNW of Petrolia, CA
  6. 1.9 5km ESE of Redway, CA
  7. 3.7 12km WSW of Petrolia, CA
  8. 2.0 5km NNW of Redway, CA
  9. 1.7 11km SSE of Redway, CA
  10. 2.5 15km W of Petrolia, CA
  11. 1.6 11km SSE of Redway, CA
  12. 2.7 12km SSE of Redway, CA
  13. 1.8 10km SSE of Redway, CA
  14. 2.0 11km SSE of Redway, CA
  15. 1.9 15km SE of Rockport, 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 6.2 on 2021-12-20 — it released about 3,700,000 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.