QuakeIndex

Earthquake · reviewed by a seismologist

M 3.1ml

9km WNW of Cobb, CA

· 1.1 km deep · released about 1,500 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Lake County 30 kmSonoma County 37 kmNapa County 57 kmColusa County 62 kmYolo County 82 kmMendocino County 85 kmMarin County 89 kmGlenn County 91 kmSutter County 99 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 3.1 (ml)
Depth
1.1 km below the surface
Felt
19 reports · strongest reported intensity IV
Nearest
Lake County, 30 km NNE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1626 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 19 people have reported feeling it to USGS.

How big was it?

This earthquake released about 1,500 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.1 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 220,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 9,800× the energy of this one
  3. Magna, Utah 2020 M 5.7 6,900× the energy of this one
  4. This earthquake M 3.1 about 1,500 lb of TNT
  5. Around the size people start to feel M 3.0 this one released 1.6× more

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 38.8462, -122.8192. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Lake County, CA 30 km (19 mi) SSW of here earthquakes near Lake County
Sonoma County, CA 37 km (23 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 62 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

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

  1. 1.6 7km WNW of Cobb, CA
  2. 1.5 4km SE of The Geysers, CA
  3. 2.2 2km NNW of The Geysers, CA
  4. 3.8 0km NNW of The Geysers, CA
  5. 1.6 4km W of Cobb, CA
  6. 1.8 1km NNW of The Geysers, CA
  7. 1.8 6km NW of The Geysers, CA
  8. 1.6 8km WNW of Cobb, CA
  9. 1.6 1km NW of The Geysers, CA
  10. 1.5 8km W of Cobb, CA
  11. 1.7 8km WNW of Upper Lake, CA
  12. 1.6 8km NW of The Geysers, CA
  13. 1.9 8km NE of Windsor, CA
  14. 1.9 2km ESE of The Geysers, CA
  15. 2.6 6km NW of The Geysers, 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 5.0 on 2016-12-14 — it released about 640 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.