QuakeIndex

Earthquake · reviewed by a seismologist

M 2.0md

Earthquake near Sea Ranch, CA

No earthquake was likely felt in Sea Ranch in the 24 hours to 6:02 am PST (14:02 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 2.0 earthquake was recorded 18 km (11 mi) northeast of Sea Ranch, CA, at 4:53 am PST on 22 December 2020 (12:53 UTC), 5.9 km deep.

USGS: 18km NE of Sea Ranch, CA

4:53 am PST, Dec 22, 2020 · · 5.9 km deep · released about 26 lb of TNT

10 km30 km60 km120 km N Sonoma County 48 kmLake County 58 kmMendocino County 68 kmNapa County 93 kmMarin County 100 kmColusa County 101 kmGlenn County 116 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
4:53 am PST on 22 December 2020 ()
Where
18 km (11 mi) northeast of Sea Ranch, CA · earthquakes near Sea Ranch
Magnitude
M 2.0 (md)
Depth
5.9 km below the surface
Felt
no reports yet
Nearest
Sonoma County, 48 km SE
Nearest mapped fault
San Andreas fault, 16 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 2142 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 14 km (9 mi) from the epicentre. In Sea Ranch, 18 km away, the estimate is intensity II (weak). 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.

Earthquakes near other towns within 30 km: Boonville, Cloverdale.

How big was it?

This earthquake released about 26 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.0 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 580,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 410,000× the energy of this one
  3. Around the size people start to feel M 3.0 36× the energy of this one
  4. This earthquake M 2.0 about 26 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

The largest earthquake within 50 km since 2016 was M 5.0 on 2016-12-14 — about 38,000 times the energy of this one.

Before 2016, the USGS record lists one earthquake of M5 or more within 50 km:

  1. 5.2 6 km ESE of Talmage, California · 37 km NNE of this epicentre

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 38.8320, -123.3128. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Sonoma County, CA 48 km (30 mi) SE earthquakes near Sonoma County
Lake County, CA 58 km (36 mi) ENE earthquakes near Lake County
Mendocino County, CA 68 km (42 mi) N earthquakes near Mendocino County
Napa County, CA 93 km (58 mi) ESE earthquakes near Napa County
Marin County, CA 100 km (62 mi) SSE earthquakes near Marin County
Colusa County, CA 101 km (62 mi) ENE earthquakes near Colusa 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. 2.2 8km SSW of Kelseyville, CA
  2. 2.5 8km SSW of Kelseyville, CA
  3. 1.5 8km SSW of Kelseyville, CA
  4. 2.1 8km SSW of Kelseyville, CA
  5. 1.9 8km SSW of Kelseyville, CA
  6. 3.0 8km SSW of Kelseyville, CA
  7. 1.5 5km WNW of Cobb, CA
  8. 1.5 8km SSW of Kelseyville, CA
  9. 1.8 8km NW of The Geysers, CA
  10. 1.8 7km NW of The Geysers, CA
  11. 2.8 7km NW of The Geysers, CA
  12. 1.9 7km WNW of The Geysers, CA
  13. 1.7 10km WNW of The Geysers, CA
  14. 1.6 8km NW of The Geysers, CA
  15. 1.6 14km ESE of Redwood Valley, 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.