QuakeIndex

Earthquake · reviewed by a seismologist

M 3.9mw

1 km NNW of The Geysers, CA

· 2.0 km deep · released about 12 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Sonoma County 32 kmLake County 36 kmNapa County 49 kmColusa County 63 kmYolo County 75 kmMarin County 82 kmSolano County 92 kmMendocino County 93 kmSutter County 96 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 3.9 (mw)
Depth
2.0 km below the surface
Felt
109 reports · strongest reported intensity IV
Measured shaking
intensity V (ShakeMap)
USGS impact alert
green
Nearest
Sonoma County, 32 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 219 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 109 people have reported feeling it to USGS.

How big was it?

This earthquake released about 12 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.9 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 14,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 640× the energy of this one
  3. Magna, Utah 2020 M 5.7 450× the energy of this one
  4. This earthquake M 3.9 about 12 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 25× 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 38.7855, -122.7625. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Sonoma County, CA 32 km (20 mi) NNE of here earthquakes near Sonoma County
Lake County, CA 36 km (22 mi) S of here earthquakes near Lake County
Napa County, CA 49 km (30 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 75 km (47 mi) W of here earthquakes near Yolo County
Marin County, CA 82 km (51 mi) N of here earthquakes near Marin County

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

Aftershocks so far

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

  1. 1.7 2 km NE of The Geysers, CA
  2. 2.1 7 km NW of The Geysers, CA
  3. 1.6 9 km WNW of The Geysers, CA
  4. 1.7 3 km ENE of The Geysers, CA
  5. 2.0 10 km ENE of Hidden Valley Lake, CA
  6. 2.0 12 km WNW of The Geysers, CA
  7. 2.1 12 km NW of The Geysers, CA
  8. 1.9 2 km NW of The Geysers, CA
  9. 1.8 8 km NW of The Geysers, CA
  10. 1.5 10 km WNW of The Geysers, CA
  11. 1.8 7 km W of Cobb, CA
  12. 1.5 8 km W of Cobb, CA
  13. 2.4 8 km WNW of Cobb, CA
  14. 1.6 5 km WNW of Cobb, CA
  15. 1.6 8 km 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 42 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.