QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6md

Earthquake near Sea Ranch, CA

No earthquake was likely felt in Sea Ranch in the 24 hours to 7:54 am PST (15:54 UTC). The last one was M 3.7, 33 km (21 mi) N, at 8:42 pm PDT on 25 September 2026, estimated intensity III (weak) in town; 134 felt reports to USGS. Every earthquake near Sea Ranch

This page: a magnitude 1.6 earthquake was recorded 36 km (22 mi) west-northwest of Sea Ranch, CA, at 12:35 pm PDT on 3 October 2022 (19:35 UTC), 3.2 km deep.

USGS: 20km SW of Point Arena, CA

12:35 pm PDT, Oct 3, 2022 · · 3.2 km deep · released about 7.8 lb of TNT

10 km30 km60 km120 km N Mendocino County 81 kmSonoma County 86 kmLake 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
12:35 pm PDT on 3 October 2022 ()
Where
36 km (22 mi) west-northwest of Sea Ranch, CA · earthquakes near Sea Ranch
Magnitude
M 1.6 (md)
Depth
3.2 km below the surface
Felt
no reports yet
Nearest
Mendocino County, 81 km NNE
Nearest mapped fault
San Andreas fault, 24 km from its surface trace — near is not the same as on
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1500 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 11 km (7 mi) from the epicentre. In Sea Ranch, 36 km away, the estimate is intensity I (not felt). Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

How big was it?

This earthquake released about 7.8 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,900,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,400,000× the energy of this one
  3. Around the size people start to feel M 3.0 120× the energy of this one
  4. This earthquake M 1.6 about 7.8 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.

For this area

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

Before 2016, the USGS record since 1900 lists no earthquake of M5 or more within 50 km.

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Epicentre 38.7798, -123.8553. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Mendocino County, CA 81 km (50 mi) NNE earthquakes near Mendocino County
Sonoma County, CA 86 km (53 mi) ESE earthquakes near Sonoma County
Lake County, CA 103 km (64 mi) ENE earthquakes near Lake County
Marin County, CA 126 km (78 mi) SE earthquakes near Marin County
San Francisco County, CA 137 km (85 mi) SSE earthquakes near San Francisco County

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

Aftershocks so far

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

  1. 1.8 16 km ESE of Navarro Head, CA
  2. 1.6 5 km ESE of Point Arena, CA
  3. 1.7 13 km NW of Fort Ross, CA
  4. 1.8 14 km NW of Fort Ross, CA
  5. 1.6 14 km NW of Fort Ross, CA
  6. 1.6 13 km NW of Fort Ross, CA
  7. 1.6 15 km ESE of Navarro Head, CA
  8. 1.6 10 km S of Boonville, CA
  9. 1.7 11 km SE of Point Arena, CA
  10. 1.5 7 km ESE of Point Arena, CA
  11. 1.9 8 km N of Point Arena, CA
  12. 1.9 16 km ESE of Navarro Head, CA
  13. 1.6 15 km ENE of Point Arena, CA
  14. 2.0 14 km WNW of Boonville, CA
  15. 1.9 6 km SSE of Point Arena, 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.