QuakeIndex

Earthquake · reviewed by a seismologist

M 3.0ml

20km NNE of Rockport, CA

· 5.7 km deep · released about 1,000 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Mendocino County 59 kmHumboldt County 90 kmTrinity County 98 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 3.0 (ml)
Depth
5.7 km below the surface
Felt
6 reports · strongest reported intensity IV
Nearest
Mendocino County, 59 km SSE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1741 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 6 people have reported feeling it to USGS.

How big was it?

This earthquake released about 1,000 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.0 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 330,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 15,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 10,000× the energy of this one
  4. This earthquake M 3.0 about 1,000 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 39.9102, -123.7552. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Mendocino County, CA 59 km (37 mi) NNW of here earthquakes near Mendocino County
Humboldt County, CA 90 km (56 mi) S of here earthquakes near Humboldt County
Trinity County, CA 98 km (61 mi) SSW of here earthquakes near Trinity County
Glenn County, CA 121 km (75 mi) WNW of here earthquakes near Glenn County
Lake County, CA 124 km (77 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

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

  1. 1.6 11km SE of Laytonville, CA
  2. 1.9 4km NNW of Laytonville, CA
  3. 2.1 30km NE of Redway, CA
  4. 1.7 19km SW of Laytonville, CA
  5. 1.9 15km N of Brooktrails, CA
  6. 1.5 2km WNW of Laytonville, CA
  7. 1.9 11km N of Covelo, CA
  8. 1.9 8km NW of Laytonville, CA
  9. 2.8 8km W of Redway, CA
  10. 1.8 8km W of Redway, CA
  11. 2.9 8km W of Redway, CA
  12. 2.0 5km WSW of Laytonville, CA
  13. 1.6 8km SSE of Laytonville, CA
  14. 1.9 26km N of Laytonville, CA
  15. 2.3 26km N of Laytonville, 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 72 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.