QuakeIndex

Earthquake · reviewed by a seismologist

M 4.2mw

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 4.2 earthquake was recorded 2 km (1 mi) west-northwest of Cobb, CA, at 4:57 am PDT on 28 June 2022 (11:57 UTC), less than 1 km deep. 82 people have reported feeling it to USGS.

USGS: 2km WNW of Cobb, CA

43 km (27 mi) N of Santa Rosa, CA · 120 km (75 mi) NNW of San Francisco, CA

4:57 am PDT, Jun 28, 2022 · · 0.5 km deep · released about 29 tons of TNT

10 km30 km60 km120 km N Lake County 31 kmSonoma County 37 kmNapa County 51 kmColusa County 59 kmYolo County 75 kmMarin County 87 kmMendocino County 90 kmGlenn County 91 kmSutter County 93 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
4:57 am PDT on 28 June 2022 ()
Where
2 km (1 mi) west-northwest of Cobb, CA · earthquakes near Cobb
Magnitude
M 4.2 (mw)
Depth
0.5 km below the surface
Felt
82 reports · strongest reported intensity V
Measured shaking
intensity V (ShakeMap)
USGS impact alert
green
Nearest
Lake County, 31 km N
Nearest mapped fault
Konocti Bay fault, 7 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 1531 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.

At this magnitude and depth, people at rest would likely notice it out to about 112 km (70 mi) from the epicentre. In Cobb, 2 km away, the estimate is intensity IV (light). 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 2 km, intensity IV · Clearlake 18 km, intensity IV · Cloverdale 24 km, intensity III · Healdsburg 27 km, intensity III · Lakeport 28 km, intensity III · Calistoga 32 km, intensity III · Windsor 32 km, intensity III · Angwin 38 km, intensity III. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 29 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.2 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 5,800× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 260× the energy of this one
  3. Magna, Utah 2020 M 5.7 180× the energy of this one
  4. This earthquake M 4.2 about 29 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 61× more

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 17 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 · 44 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 38.8302, -122.7472. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Lake County, CA 31 km (19 mi) N earthquakes near Lake County
Sonoma County, CA 37 km (23 mi) SSW earthquakes near Sonoma County
Napa County, CA 51 km (32 mi) SE earthquakes near Napa County
Colusa County, CA 59 km (36 mi) NE earthquakes near Colusa County
Yolo County, CA 75 km (47 mi) ESE earthquakes near Yolo County
Marin County, CA 87 km (54 mi) S earthquakes near Marin 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. 2.0 2km W of Anderson Springs, CA
  2. 1.8 8km WNW of Cobb, CA
  3. 1.5 13km ESE of Angwin, CA
  4. 1.9 7km WNW of Cobb, CA
  5. 1.6 8km WNW of Cobb, CA
  6. 2.2 7km NW of The Geysers, CA
  7. 2.6 2km NNW of The Geysers, CA
  8. 1.6 2km ESE of The Geysers, CA
  9. 1.9 7km NNE of Cloverdale, CA
  10. 2.4 7km ENE of Hidden Valley Lake, CA
  11. 2.4 8km NW of The Geysers, CA
  12. 1.5 6km WNW of The Geysers, CA
  13. 2.8 4km SW of Anderson Springs, CA
  14. 2.0 4km SSW of Anderson Springs, CA
  15. 1.9 8km NW of The Geysers, 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.