QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1md

9 km WNW of Cobb, California

· 1.9 km deep · released about 38 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Lake County 31 kmSonoma County 36 kmNapa County 57 kmColusa County 63 kmYolo County 82 kmMendocino County 85 kmMarin County 88 kmGlenn County 92 kmSutter County 100 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 2.1 (md)
Depth
1.9 km below the surface
Felt
no reports yet
Nearest
Lake County, 31 km NNE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3515 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 38 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 390,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 280,000× the energy of this one
  3. Around the size people start to feel M 3.0 25× the energy of this one
  4. This earthquake M 2.1 about 38 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 38.8392, -122.8262. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Lake County, CA 31 km (19 mi) SSW of here earthquakes near Lake County
Sonoma County, CA 36 km (22 mi) NNE of here earthquakes near Sonoma County
Napa County, CA 57 km (35 mi) NW of here earthquakes near Napa County
Colusa County, CA 63 km (39 mi) SW of here earthquakes near Colusa County
Yolo County, CA 82 km (51 mi) WNW of here earthquakes near Yolo County
Mendocino County, CA 85 km (53 mi) SE of here earthquakes near Mendocino County

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

Aftershocks so far

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

  1. 1.5 6 km ENE of Cloverdale, California
  2. 1.9 5 km WNW of Cobb, California
  3. 1.5 9 km WNW of Cobb, California
  4. 1.9 6 km W of Cobb, California
  5. 1.6 7 km S of Cobb, California
  6. 1.7 8 km NE of Boonville, California
  7. 1.6 3 km S of Cobb, California
  8. 1.9 3 km SSW of Cobb, California
  9. 1.8 3 km S of Cobb, California
  10. 1.9 3 km S of Cobb, California
  11. 1.8 2 km SSW of Cobb, California
  12. 1.5 10 km W of Cobb, California
  13. 1.7 10 km W of Cobb, California
  14. 1.6 10 km W of Cobb, California
  15. 1.7 1 km NW of Middletown, California

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.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.