QuakeIndex

Earthquake · reviewed by a seismologist

M 2.6md

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 2.6 earthquake was recorded 4 km (2 mi) northwest of Cobb, CA, at 12:15 pm PST on 11 February 2020 (20:15 UTC), 1.3 km deep. 2 people have reported feeling it to USGS.

USGS: 4km NW of Cobb, CA

44 km (28 mi) N of Santa Rosa, CA · 122 km (76 mi) NNW of San Francisco, CA

12:15 pm PST, Feb 11, 2020 · · 1.3 km deep · released about 220 lb of TNT

10 km30 km60 km120 km N Lake County 29 kmSonoma County 38 kmNapa County 53 kmColusa County 58 kmYolo County 76 kmMarin County 88 kmMendocino County 88 kmGlenn County 90 kmSutter 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
12:15 pm PST on 11 February 2020 ()
Where
4 km (2 mi) northwest of Cobb, CA · earthquakes near Cobb
Magnitude
M 2.6 (md)
Depth
1.3 km below the surface
Felt
2 reports · strongest reported intensity III
Nearest
Lake County, 29 km N
Nearest mapped fault
Konocti Bay fault, 6 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 2391 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 23 km (14 mi) from the epicentre. In Cobb, 4 km away, the estimate is intensity III (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 4 km, intensity III · Clearlake 17 km, intensity II · Cloverdale 23 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 220 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 68,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 48,000× the energy of this one
  3. Around the size people start to feel M 3.0 4.3× the energy of this one
  4. This earthquake M 2.6 about 220 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 4,400 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 · 42 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 38.8435, -122.7572. 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 53 km (33 mi) SE earthquakes near Napa County
Colusa County, CA 58 km (36 mi) NE earthquakes near Colusa County
Yolo County, CA 76 km (47 mi) ESE earthquakes near Yolo County
Marin County, CA 88 km (55 mi) S earthquakes near Marin County

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

Aftershocks so far

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

  1. 2.4 9km NNW of Healdsburg, CA
  2. 1.9 6km WNW of The Geysers, CA
  3. 2.2 16km ESE of Boonville, CA
  4. 2.1 7km NW of The Geysers, CA
  5. 1.6 6km NE of Cloverdale, CA
  6. 1.9 6km NW of The Geysers, CA
  7. 1.5 8km NW of The Geysers, CA
  8. 2.6 2km NNW of The Geysers, CA
  9. 1.5 7km NW of The Geysers, CA
  10. 2.0 7km W of Cobb, CA
  11. 1.5 7km W of Cobb, CA
  12. 3.7 7km W of Cobb, CA
  13. 1.6 7km WSW of Clearlake, CA
  14. 2.1 2km N of The Geysers, CA
  15. 1.5 7km WNW 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.