QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

21km NNW of Boonville, CA

· 1.7 km deep · released about 17 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Mendocino County 29 kmLake County 64 kmSonoma County 87 kmGlenn County 104 kmColusa County 107 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
1.7 km below the surface
Felt
no reports yet
Nearest
Mendocino County, 29 km N
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1570 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 39.1745, -123.4810. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Mendocino County, CA 29 km (18 mi) S of here earthquakes near Mendocino County
Lake County, CA 64 km (40 mi) W of here earthquakes near Lake County
Sonoma County, CA 87 km (54 mi) NNW of here earthquakes near Sonoma County
Glenn County, CA 104 km (65 mi) WSW of here earthquakes near Glenn County
Colusa County, CA 107 km (67 mi) W of here earthquakes near Colusa County
Napa County, CA 125 km (77 mi) NW of here earthquakes near Napa County

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

Aftershocks so far

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

  1. 1.7 5km ENE of Willits, CA
  2. 2.1 9km ESE of Willits, CA
  3. 1.6 14km WSW of Brooktrails, CA
  4. 1.6 12km W of Lake Pillsbury, CA
  5. 1.6 12km NNE of Point Arena, CA
  6. 1.8 12km WNW of Lake Pillsbury, CA
  7. 2.4 3km E of Willits, CA
  8. 1.7 5km ENE of Willits, CA
  9. 2.3 13km WNW of Redwood Valley, CA
  10. 2.3 13km W of Lake Pillsbury, CA
  11. 1.9 12km W of Lake Pillsbury, CA
  12. 1.8 14km N of Brooktrails, CA
  13. 1.6 16km NW of Lake Pillsbury, CA
  14. 1.5 10km ESE of Willits, CA
  15. 1.6 12km W of Lake Pillsbury, 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 4.4 on 2020-12-06 — it released about 6,900 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.