QuakeIndex

Earthquake · automatic estimate, may change

M 1.6md

Earthquake near Cobb, CA

No earthquake was likely felt in Cobb in the 24 hours to 11:34 am PST (19:34 UTC). The last one was M 1.6, 5 km (3 mi) S, at 5:12 am PST on 10 November 2026, estimated intensity II (weak) in town. Every earthquake near Cobb

This page: a magnitude 1.6 earthquake was recorded 10 km (6 mi) west-northwest of Cobb, CA, at 12:11 am PDT on 4 October 2026 (07:11 UTC), 1.4 km deep. The magnitude and location are an automatic first estimate and may change.

USGS: 10 km WNW of Cobb, CA

48 km (30 mi) NNW of Santa Rosa, CA · 126 km (78 mi) NNW of San Francisco, CA

12:11 am PDT, Oct 4, 2026 · · 1.4 km deep · released about 6.4 lb of TNT

10 km30 km60 km120 km N Lake County 28 kmSonoma County 39 kmNapa County 59 kmColusa County 61 kmYolo County 82 kmMendocino County 83 kmGlenn County 90 kmMarin County 91 kmSutter County 99 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
12:11 am PDT on 4 October 2026 ()
Where
10 km (6 mi) west-northwest of Cobb, CA · earthquakes near Cobb
Magnitude
M 1.6 (md)
Depth
1.4 km below the surface
Felt
no reports yet
Nearest
Lake County, 28 km NNE
Nearest mapped fault
Konocti Bay fault, 9 km from its surface trace — near is not the same as on
Status
Automatic — a machine’s first estimate, which may change

USGS · last changed by USGS · we first saw it 39 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 Cobb, 10 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 10 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 6.4 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,400,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,700,000× the energy of this one
  3. Around the size people start to feel M 3.0 150× the energy of this one
  4. This earthquake M 1.6 about 6.4 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 150,000 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 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 38.8653, -122.8223. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Lake County, CA 28 km (17 mi) NNE earthquakes near Lake County
Sonoma County, CA 39 km (24 mi) SSW earthquakes near Sonoma County
Napa County, CA 59 km (36 mi) SE earthquakes near Napa County
Colusa County, CA 61 km (38 mi) NE earthquakes near Colusa County
Yolo County, CA 82 km (51 mi) ESE earthquakes near Yolo County
Mendocino County, CA 83 km (51 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. 0.3 6 km WNW of Cobb, CA
  2. 0.8 4 km NNW of The Geysers, CA
  3. 1.3 7 km NW of The Geysers, CA
  4. 1.0 10 km WNW of Cobb, CA
  5. 1.1 6 km WNW of The Geysers, CA
  6. 0.8 6 km WNW of The Geysers, CA
  7. 1.0 2 km N of The Geysers, CA
  8. 1.2 2 km N of The Geysers, CA
  9. 0.8 13 km NW of The Geysers, CA
  10. 0.8 12 km WNW of The Geysers, CA
  11. 0.7 6 km WNW of Cobb, CA
  12. 0.9 10 km NW of The Geysers, CA
  13. 0.8 1 km NE of The Geysers, CA
  14. 1.1 6 km NW of The Geysers, CA
  15. 1.1 4 km W of Cobb, 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.