QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

13km NNE of Brooktrails, CA

· 9.2 km deep · released about 17 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Mendocino County 17 kmLake County 71 kmGlenn County 80 kmColusa County 103 kmTehama County 113 kmSonoma County 120 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
9.2 km below the surface
Felt
no reports yet
Nearest
Mendocino County, 17 km SW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2069 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 17 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 5.8 900,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 640,000× the energy of this one
  3. Around the size people start to feel M 3.0 57× the energy of this one
  4. This earthquake M 1.8 about 17 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 39.5555, -123.3343. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Mendocino County, CA 17 km (10 mi) NE of here earthquakes near Mendocino County
Lake County, CA 71 km (44 mi) NW of here earthquakes near Lake County
Glenn County, CA 80 km (50 mi) W of here earthquakes near Glenn County
Colusa County, CA 103 km (64 mi) WNW of here earthquakes near Colusa County
Tehama County, CA 113 km (71 mi) WSW of here earthquakes near Tehama County
Sonoma County, CA 120 km (74 mi) NNW of here earthquakes near Sonoma County

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

Aftershocks so far

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

  1. 2.3 4km NE of Laytonville, CA
  2. 1.7 5km NNW of Lake Pillsbury, CA
  3. 1.6 4km ENE of Laytonville, CA
  4. 1.6 1km W of Lake Pillsbury, CA
  5. 1.7 16km NE of Willits, CA
  6. 3.9 15km NNW of Lake Pillsbury, CA
  7. 2.0 12km NNE of Brooktrails, CA
  8. 1.7 8km ESE of Willits, CA
  9. 1.5 6km E of Redwood Valley, CA
  10. 1.5 4km ESE of Laytonville, CA
  11. 1.5 8km NNW of Redwood Valley, CA
  12. 1.5 12km N of Brooktrails, CA
  13. 1.7 4km S of Redwood Valley, CA
  14. 1.8 2km N of Lake Pillsbury, CA
  15. 1.5 12km WNW of Upper Lake, 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 2019-04-29 — it released about 5,400 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.