QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

18km W of Sea Ranch, CA

· 3.0 km deep · released about 13 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Sonoma County 68 kmMendocino County 80 kmLake County 89 kmMarin County 110 kmNapa County 119 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
3.0 km below the surface
Felt
no reports yet
Nearest
Sonoma County, 68 km ESE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1780 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 13 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 5.7 810,000× the energy of this one
  3. Around the size people start to feel M 3.0 72× the energy of this one
  4. This earthquake M 1.8 about 13 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 38.7367, -123.6608. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Sonoma County, CA 68 km (42 mi) WNW of here earthquakes near Sonoma County
Mendocino County, CA 80 km (49 mi) SSW of here earthquakes near Mendocino County
Lake County, CA 89 km (56 mi) WSW of here earthquakes near Lake County
Marin County, CA 110 km (69 mi) NW of here earthquakes near Marin County
Napa County, CA 119 km (74 mi) WNW of here earthquakes near Napa County
San Francisco County, CA 125 km (78 mi) NNW of here earthquakes near San Francisco County

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

Aftershocks so far

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

  1. 1.9 16 km NNE of Point Arena, CA
  2. 1.6 15 km ENE of Point Arena, CA
  3. 2.0 15km NE of Point Arena, CA
  4. 2.2 15km NE of Point Arena, CA
  5. 1.5 4km SSE of Point Arena, CA
  6. 1.5 16km SE of Boonville, CA
  7. 1.6 2km SW of Point Arena, CA
  8. 1.6 1km SW of Point Arena, CA
  9. 1.8 6km E of Point Arena, CA
  10. 1.7 7km ESE of Point Arena, CA
  11. 1.6 16km ESE of Navarro Head, CA
  12. 1.9 4km ESE of Point Arena, CA
  13. 3.6 4km SE of Point Arena, CA
  14. 2.2 21km SW of Point Arena, CA
  15. 1.7 5km SSE of Navarro Head, 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.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.