QuakeIndex

Earthquake · reviewed by a seismologist

M 1.9md

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 1.9 earthquake was recorded 3 km (2 mi) west of Cobb, CA, at 5:10 am PDT on 3 June 2023 (12:10 UTC), 1.8 km deep. 2 people have reported feeling it to USGS.

USGS: 3km W of Cobb, CA

42 km (26 mi) N of Santa Rosa, CA · 119 km (74 mi) NNW of San Francisco, CA

5:10 am PDT, Jun 3, 2023 · · 1.8 km deep · released about 24 lb of TNT

10 km30 km60 km120 km N Lake County 32 kmSonoma County 36 kmNapa County 51 kmColusa County 60 kmYolo County 76 kmMarin County 85 kmMendocino County 90 kmGlenn County 92 kmSolano County 94 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
5:10 am PDT on 3 June 2023 ()
Where
3 km (2 mi) west of Cobb, CA · earthquakes near Cobb
Magnitude
M 1.9 (md)
Depth
1.8 km below the surface
Felt
2 reports
Nearest
Lake County, 32 km N
Nearest mapped fault
Konocti Bay 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 1256 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 15 km (9 mi) from the epicentre. In Cobb, 3 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 3 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 24 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 640,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 450,000× the energy of this one
  3. Around the size people start to feel M 3.0 40× the energy of this one
  4. This earthquake M 1.9 about 24 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 42,000 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 · 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 38.8192, -122.7607. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Lake County, CA 32 km (20 mi) N earthquakes near Lake County
Sonoma County, CA 36 km (22 mi) SSW earthquakes near Sonoma County
Napa County, CA 51 km (32 mi) SE earthquakes near Napa County
Colusa County, CA 60 km (37 mi) NE earthquakes near Colusa County
Yolo County, CA 76 km (47 mi) ESE earthquakes near Yolo County
Marin County, CA 85 km (53 mi) S earthquakes near Marin County

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

Aftershocks so far

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

  1. 1.6 1km WSW of Anderson Springs, CA
  2. 1.5 8km WNW of Cobb, CA
  3. 1.6 14km NE of Upper Lake, CA
  4. 2.1 7km W of Cobb, CA
  5. 1.6 8km NW of The Geysers, CA
  6. 2.0 7km NW of The Geysers, CA
  7. 1.7 1km NE of The Geysers, CA
  8. 2.1 3km W of Cobb, CA
  9. 1.6 0km NNW of The Geysers, CA
  10. 1.5 16km SE of Boonville, CA
  11. 1.7 7km WNW of Cobb, CA
  12. 1.7 5km NW of The Geysers, CA
  13. 1.6 3km NE of The Geysers, CA
  14. 1.7 4km E of Upper Lake, CA
  15. 1.9 2km 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.