QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

18km SSE of Shelter Cove, CA

· 3.5 km deep · released about 15 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Mendocino County 68 kmHumboldt County 91 kmTrinity 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
3.5 km below the surface
Felt
no reports yet
Nearest
Mendocino County, 68 km SE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1206 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 15 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 1,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 710,000× the energy of this one
  3. Around the size people start to feel M 3.0 63× the energy of this one
  4. This earthquake M 1.8 about 15 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 39.8887, -123.9768. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Mendocino County, CA 68 km (42 mi) NW of here earthquakes near Mendocino County
Humboldt County, CA 91 km (57 mi) S of here earthquakes near Humboldt County
Trinity County, CA 112 km (69 mi) SW of here earthquakes near Trinity County
Lake County, CA 137 km (85 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

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

  1. 2.8 19 km E of Petrolia, CA
  2. 3.0 19 km E of Petrolia, CA
  3. 4.8 20 km E of Petrolia, CA
  4. 2.2 9 km NNE of Rockport, CA
  5. 1.6 14 km NW of Laytonville, CA
  6. 1.7 10 km SSE of Redway, CA
  7. 2.3 14 km NW of Laytonville, CA
  8. 2.3 6 km W of Laytonville, CA
  9. 1.7 7 km WSW of Laytonville, CA
  10. 2.3 4 km ESE of Redway, CA
  11. 2.9 14 km S of Redway, CA
  12. 2.1 14 km SE of Petrolia, CA
  13. 1.9 15 km SE of Petrolia, CA
  14. 1.6 14 km SE of Petrolia, CA
  15. 1.7 11 km SSE of Redway, 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 4.3 on 2017-12-14 — it released about 4,900 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.