QuakeIndex

Earthquake · automatic estimate, may change

M 0.9md

Earthquake near Cobb, CA

USGS: 8 km WNW of Cobb, CA

46 km (29 mi) N of Santa Rosa, CA · 124 km (77 mi) NNW of San Francisco, CA

5:30 pm PDT, Sep 29, 2026 · · 12 km deep · released about 0.61 lb of TNT

10 km30 km60 km120 km N Lake County 29 kmSonoma County 38 kmNapa County 57 kmColusa County 61 kmYolo County 81 kmMendocino County 84 kmMarin County 89 kmGlenn County 90 kmSutter County 98 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
5:30 pm PDT on 29 September 2026 ()
Where
8 km (5 mi) WNW of Cobb, CA · earthquakes near Cobb
Magnitude
M 0.9 (md)
Depth
12 km below the surface
Felt
no reports yet
Nearest
Lake County, 29 km N
Nearest mapped fault
Konocti Bay fault, 8 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 3 days ago

A magnitude 0.9 earthquake was recorded 8 km (5 mi) WNW of Cobb, CA, at 5:30 pm PDT on 29 September 2026 (00:30 UTC). This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

Earthquakes near other towns within 30 km: Clear Lake Riviera, Kelseyville, Soda Bay, Lower Lake, Cloverdale, Clearlake.

How big was it?

This earthquake released about 0.61 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 1.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 25,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 18,000,000× the energy of this one
  3. Around the size people start to feel M 3.0 1,600× the energy of this one
  4. This earthquake M 0.9 about 0.61 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 1,600,000 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 · 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 38.8545, -122.8088. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Lake County, CA 29 km (18 mi) N earthquakes near Lake County
Sonoma County, CA 38 km (24 mi) SSW earthquakes near Sonoma County
Napa County, CA 57 km (35 mi) SE earthquakes near Napa County
Colusa County, CA 61 km (38 mi) NE earthquakes near Colusa County
Yolo County, CA 81 km (50 mi) ESE 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

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

  1. 1.0 7 km WNW of Cobb, CA
  2. 0.8 6 km WNW of Cobb, CA
  3. 1.1 6 km NNW of The Geysers, CA
  4. 1.7 8 km ESE of Cloverdale, CA
  5. 0.2 5 km WNW of Cobb, CA
  6. 0.8 5 km NW of The Geysers, CA
  7. 0.2 6 km W of Cobb, CA
  8. 1.0 13 km NW of The Geysers, CA
  9. 1.4 7 km ESE of Cloverdale, CA
  10. 0.4 8 km WNW of Cobb, CA
  11. 0.8 8 km W of Cobb, CA
  12. 0.8 8 km WNW of Cobb, CA
  13. 1.3 8 km ESE of Cloverdale, CA
  14. 1.1 8 km W of Cobb, CA
  15. 0.7 8 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.