QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

10km E of Healdsburg, CA

· 9.2 km deep · released about 17 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Sonoma County 18 kmNapa County 40 kmLake County 54 kmMarin County 64 kmYolo County 74 kmColusa County 76 kmSolano County 82 kmSutter County 102 kmSan Francisco 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 1.8 (md)
Depth
9.2 km below the surface
Felt
no reports yet
Nearest
Sonoma County, 18 km SW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2917 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 17 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 5.8 870,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 620,000× the energy of this one
  3. Around the size people start to feel M 3.0 55× the energy of this one
  4. This earthquake M 1.8 about 17 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 38.6250, -122.7572. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Sonoma County, CA 18 km (11 mi) NE of here earthquakes near Sonoma County
Napa County, CA 40 km (25 mi) WNW of here earthquakes near Napa County
Lake County, CA 54 km (33 mi) S of here earthquakes near Lake County
Marin County, CA 64 km (40 mi) N of here earthquakes near Marin County
Yolo County, CA 74 km (46 mi) W of here earthquakes near Yolo County
Colusa County, CA 76 km (47 mi) SW of here earthquakes near Colusa 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 The Geysers, CA
  2. 1.6 2km E of The Geysers, CA
  3. 1.7 4km W of Cobb, CA
  4. 1.9 16km SE of Hidden Valley Lake, CA
  5. 1.5 6km WNW of The Geysers, CA
  6. 1.9 4km NW of The Geysers, CA
  7. 1.5 7km NW of The Geysers, CA
  8. 1.7 2km ESE of The Geysers, CA
  9. 1.5 6km WNW of The Geysers, CA
  10. 1.5 15km SW of Lakeport, CA
  11. 1.5 1km NNE of The Geysers, CA
  12. 1.8 2km ESE of The Geysers, CA
  13. 1.6 6km W of Cobb, CA
  14. 1.5 6km WNW of Cobb, CA
  15. 1.8 7km 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 57,000 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.