QuakeIndex

Earthquake · reviewed by a seismologist

M 3.9mw

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 3.9 earthquake was recorded 7 km (4 mi) west-northwest of Cobb, CA, at 6:44 pm PDT on 3 June 2019 (01:44 UTC), 2.9 km deep. 82 people have reported feeling it to USGS.

USGS: 7km WNW of Cobb, CA

44 km (27 mi) N of Santa Rosa, CA · 122 km (76 mi) NNW of San Francisco, CA

6:44 pm PDT, Jun 3, 2019 · · 2.9 km deep · released about 10 tons of TNT

10 km30 km60 km120 km N Lake County 31 kmSonoma County 36 kmNapa County 55 kmColusa County 62 kmYolo County 79 kmMendocino County 87 kmMarin County 87 kmGlenn County 92 kmSutter County 97 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
6:44 pm PDT on 3 June 2019 ()
Where
7 km (4 mi) west-northwest of Cobb, CA · earthquakes near Cobb
Magnitude
M 3.9 (mw)
Depth
2.9 km below the surface
Felt
82 reports · strongest reported intensity VI
Measured shaking
intensity VI (ShakeMap)
Nearest
Lake County, 31 km N
Nearest mapped fault
Konocti Bay 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 2634 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 88 km (55 mi) from the epicentre. In Cobb, 7 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 7 km, intensity IV · Cloverdale 19 km, intensity III · Clearlake 20 km, intensity III · Lakeport 25 km, intensity III · Healdsburg 26 km, intensity III · Windsor 32 km, intensity III · Calistoga 34 km, intensity III · Upper Lake 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 10 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.9 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 17,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 760× the energy of this one
  3. Magna, Utah 2020 M 5.7 540× the energy of this one
  4. This earthquake M 3.9 about 10 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 21× 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 50 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 · 41 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 38.8337, -122.7973. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Lake County, CA 31 km (19 mi) N earthquakes near Lake County
Sonoma County, CA 36 km (22 mi) SSW earthquakes near Sonoma County
Napa County, CA 55 km (34 mi) SE earthquakes near Napa County
Colusa County, CA 62 km (38 mi) NE earthquakes near Colusa County
Yolo County, CA 79 km (49 mi) ESE earthquakes near Yolo County
Mendocino County, CA 87 km (54 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. 1.6 10km NW of The Geysers, CA
  2. 1.7 13km ENE of Cloverdale, CA
  3. 2.0 4km W of Cobb, CA
  4. 2.0 2km NW of The Geysers, CA
  5. 2.5 7km WNW of The Geysers, CA
  6. 3.2 13km W of Lakeport, CA
  7. 1.7 7km N of Kenwood, CA
  8. 1.7 12km WNW of The Geysers, CA
  9. 1.6 3km W of Cobb, CA
  10. 2.0 2km SSW of Anderson Springs, CA
  11. 2.3 4km SW of Anderson Springs, CA
  12. 2.5 2km NW of The Geysers, CA
  13. 1.9 6km WNW of The Geysers, CA
  14. 1.7 6km NNW of The Geysers, CA
  15. 2.4 3km 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.