QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

38km SSW of Hayfork, CA

· 22 km deep · released about 15 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Trinity County 50 kmHumboldt County 76 kmMendocino County 89 kmTehama County 90 kmGlenn County 102 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
Trinity County, 50 km NNE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3221 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 5.7 730,000× the energy of this one
  3. Around the size people start to feel M 3.0 65× 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 40.2197, -123.2892. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Trinity County, CA 50 km (31 mi) SSW of here earthquakes near Trinity County
Humboldt County, CA 76 km (47 mi) SE of here earthquakes near Humboldt County
Mendocino County, CA 89 km (55 mi) N of here earthquakes near Mendocino County
Tehama County, CA 90 km (56 mi) W of here earthquakes near Tehama County
Glenn County, CA 102 km (63 mi) NW of here earthquakes near Glenn County
Shasta County, CA 121 km (75 mi) WSW of here earthquakes near Shasta County

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

Aftershocks so far

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

  1. 1.7 42km NW of Rancho Tehama Reserve, CA
  2. 1.7 40km NE of Covelo, CA
  3. 2.4 41km NE of Covelo, CA
  4. 2.0 8km NE of Covelo, CA
  5. 2.0 37km NNE of Redway, CA
  6. 2.0 16km N of Laytonville, CA
  7. 2.5 38km NNE of Redway, CA
  8. 1.8 39km NE of Covelo, CA
  9. 1.9 9km NNW of Hayfork, CA
  10. 3.0 8km NNW of Hayfork, CA
  11. 2.3 16km N of Laytonville, CA
  12. 1.8 32km NNW of Alder Springs, CA
  13. 1.6 27km NNW of Covelo, CA
  14. 1.6 27km NNW of Covelo, CA
  15. 1.8 6km N of Hayfork, 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 4.5 on 2016-08-28 — it released about 11,000 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.