QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1md

9 km NE of Healdsburg, California

· 2.2 km deep · released about 38 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Sonoma County 20 kmNapa County 43 kmLake County 50 kmMarin County 68 kmColusa County 74 kmYolo County 76 kmSolano County 85 kmSutter County 102 kmMendocino County 103 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
2.2 km below the surface
Felt
no reports yet
Nearest
Sonoma County, 20 km SW
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 38.6613, -122.7765. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Sonoma County, CA 20 km (12 mi) NE of here earthquakes near Sonoma County
Napa County, CA 43 km (27 mi) WNW of here earthquakes near Napa County
Lake County, CA 50 km (31 mi) S of here earthquakes near Lake County
Marin County, CA 68 km (42 mi) N of here earthquakes near Marin County
Colusa County, CA 74 km (46 mi) SW of here earthquakes near Colusa County
Yolo County, CA 76 km (47 mi) W of here earthquakes near Yolo County

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

Aftershocks so far

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

  1. 2.4 7 km NNE of Hopland, California
  2. 1.7 10 km WNW of Cobb, California
  3. 1.5 7 km WSW of Cobb, California
  4. 1.9 6 km S of Cobb, California
  5. 1.6 11 km W of Cobb, California
  6. 1.7 10 km W of Cobb, California
  7. 1.9 7 km NNE of Hopland, California
  8. 2.0 5 km SSW of Cobb, California
  9. 1.7 3 km ESE of Lower Lake, California
  10. 1.9 10 km W of Cobb, California
  11. 2.0 5 km SSW of Cobb, California
  12. 1.8 7 km W of Cobb, California
  13. 1.6 6 km W of Cobb, California
  14. 1.9 7 km W of Cobb, California
  15. 1.9 10 km W of Cobb, 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.