QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

11km NNW of Healdsburg, CA

· 6.8 km deep · released about 14 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Sonoma County 20 kmLake County 47 kmNapa County 55 kmMarin County 74 kmColusa County 78 kmYolo County 87 kmMendocino County 93 kmSolano County 97 kmGlenn County 109 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
6.8 km below the surface
Felt
no reports yet
Nearest
Sonoma County, 20 km S
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2753 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 14 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 1,100,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 760,000× the energy of this one
  3. Around the size people start to feel M 3.0 68× the energy of this one
  4. This earthquake M 1.8 about 14 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 38.7052, -122.9003. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Sonoma County, CA 20 km (13 mi) N of here earthquakes near Sonoma County
Lake County, CA 47 km (29 mi) SSW of here earthquakes near Lake County
Napa County, CA 55 km (34 mi) WNW of here earthquakes near Napa County
Marin County, CA 74 km (46 mi) N of here earthquakes near Marin County
Colusa County, CA 78 km (48 mi) SW of here earthquakes near Colusa County
Yolo County, CA 87 km (54 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

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

  1. 1.6 6km WNW of Cobb, CA
  2. 2.1 18km S of Boonville, CA
  3. 1.7 5km WNW of Cobb, CA
  4. 1.7 6km NW of The Geysers, CA
  5. 1.9 6km NW of The Geysers, CA
  6. 2.2 8km WNW of The Geysers, CA
  7. 1.6 4km W of Cobb, CA
  8. 2.1 4km W of Cobb, CA
  9. 1.9 4km W of Cobb, CA
  10. 1.9 6km NNW of The Geysers, CA
  11. 2.1 3km SE of The Geysers, CA
  12. 1.8 6km NNW of The Geysers, CA
  13. 1.9 10km NW of The Geysers, CA
  14. 1.6 10km NW of The Geysers, CA
  15. 1.6 3km W 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 70,000 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.