QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6md

Earthquake near Cobb, CA

Yes: an earthquake was likely felt in Cobb in the last 24 hours. M 1.6, 4 km (2 mi) W of Cobb, at 1:30 pm PST on 11 November 2026 (21:30 UTC); the estimated shaking in Cobb was intensity II (weak). Every earthquake near Cobb

This page: a magnitude 1.6 earthquake was recorded 11 km (7 mi) west of Cobb, CA, at 11:23 pm PST on 4 December 2016 (07:23 UTC), 1.9 km deep.

USGS: 11 km W of Cobb, California

45 km (28 mi) NNW of Santa Rosa, CA · 123 km (76 mi) NNW of San Francisco, CA

11:23 pm PST, Dec 4, 2016 · · 1.9 km deep · released about 8.1 lb of TNT

10 km30 km60 km120 km N Lake County 32 kmSonoma County 35 kmNapa County 58 kmColusa County 65 kmYolo County 84 kmMendocino County 84 kmMarin County 87 kmGlenn County 94 kmSolano County 101 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
11:23 pm PST on 4 December 2016 ()
Where
11 km (7 mi) west of Cobb, CA · earthquakes near Cobb
Magnitude
M 1.6 (md)
Depth
1.9 km below the surface
Felt
no reports yet
Nearest
Lake County, 32 km NNE
Nearest mapped fault
Maacama fault, 9 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 3561 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 Cobb, 11 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.

Likely felt in: Cobb 11 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 8.1 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 1,300,000× 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 8.1 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 lists one earthquake of M5 or more within 50 km:

  1. 5.2 6 km ESE of Talmage, California · 38 km NW 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 38.8303, -122.8493. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Lake County, CA 32 km (20 mi) NNE earthquakes near Lake County
Sonoma County, CA 35 km (21 mi) S earthquakes near Sonoma County
Napa County, CA 58 km (36 mi) SE earthquakes near Napa County
Colusa County, CA 65 km (41 mi) NE earthquakes near Colusa County
Yolo County, CA 84 km (52 mi) E earthquakes near Yolo County
Mendocino County, CA 84 km (52 mi) NW earthquakes near Mendocino 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. 1.5 8 km WNW of Cobb, California
  2. 1.7 7 km W of Cobb, California
  3. 1.9 Northern California
  4. 1.9 12 km E of Geyserville, California
  5. 1.5 4 km S of Cobb, California
  6. 1.7 9 km WNW of Cobb, California
  7. 1.5 7 km S of Cobb, California
  8. 1.8 3 km W of Cobb, California
  9. 1.6 9 km WNW of Cobb, California
  10. 2.5 5 km WNW of Cobb, California
  11. 2.5 5 km WNW of Cobb, California
  12. 2.7 1 km NNE of Boonville, California
  13. 1.5 7 km W of Cobb, California
  14. 2.1 7 km S of Cobb, California
  15. 2.4 7 km S of Cobb, California

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.