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 7:29 pm PST (03:29 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 13 km (8 mi) northwest of Sea Ranch, CA, at 12:45 pm PST on 19 November 2018 (20:45 UTC), 2.7 km deep.

USGS: 13km NW of Sea Ranch, CA

84 km (52 mi) WNW of Santa Rosa, CA

12:45 pm PST, Nov 19, 2018 · · 2.7 km deep · released about 6.8 lb of TNT

10 km30 km60 km120 km N Sonoma County 63 kmMendocino County 70 kmLake County 77 kmMarin County 110 kmNapa County 111 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
12:45 pm PST on 19 November 2018 ()
Where
13 km (8 mi) northwest of Sea Ranch, CA · earthquakes near Sea Ranch
Magnitude
M 1.6 (md)
Depth
2.7 km below the surface
Felt
no reports yet
Nearest
Sonoma County, 63 km ESE
Nearest mapped fault
San Andreas fault, 8 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 2914 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 10 km (6 mi) from the epicentre. In Sea Ranch, 13 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.

How big was it?

This earthquake released about 6.8 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 2,200,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,600,000× the energy of this one
  3. Around the size people start to feel M 3.0 140× the energy of this one
  4. This earthquake M 1.6 about 6.8 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 38.8090, -123.5502. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Sonoma County, CA 63 km (39 mi) ESE earthquakes near Sonoma County
Mendocino County, CA 70 km (43 mi) N earthquakes near Mendocino County
Lake County, CA 77 km (48 mi) ENE earthquakes near Lake County
Marin County, CA 110 km (68 mi) SE earthquakes near Marin County
Napa County, CA 111 km (69 mi) ESE earthquakes near Napa County
Colusa County, CA 121 km (75 mi) ENE earthquakes near Colusa County

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

Aftershocks so far

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

  1. 2.1 2km NNW of Talmage, CA
  2. 1.9 15km ESE of Navarro Head, CA
  3. 1.8 15km ESE of Navarro Head, CA
  4. 2.3 2km NNW of Talmage, CA
  5. 1.9 14km WSW of Lakeport, CA
  6. 3.1 15km ESE of Navarro Head, CA
  7. 1.6 18km NW of Cloverdale, CA
  8. 1.8 7km W of Fort Ross, CA
  9. 1.9 5km E of Boonville, CA
  10. 1.9 13km SW of Lakeport, CA
  11. 1.8 21km NE of Sea Ranch, CA
  12. 2.5 16km ESE of Navarro Head, CA
  13. 1.8 16km ESE of Navarro Head, CA
  14. 1.7 16km ESE of Navarro Head, CA
  15. 2.3 5km S of Talmage, 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.