QuakeIndex

Earthquake · reviewed by a seismologist

M 2.4md

Earthquake near Lakeport, CA

No earthquake was likely felt in Lakeport in the 24 hours to 1:31 pm PST (21:31 UTC). The last one was M 4.0, 51 km (32 mi) N, at 5:01 am PDT on 28 October 2026, estimated intensity II (weak) in town; 14 felt reports to USGS. Every earthquake near Lakeport

This page: a magnitude 2.4 earthquake was recorded 13 km (8 mi) west of Lakeport, CA, at 12:56 am PST on 16 December 2020 (08:56 UTC), 3.7 km deep. 9 people have reported feeling it to USGS.

USGS: 13km W of Lakeport, CA

12:56 am PST, Dec 16, 2020 · · 3.7 km deep · released about 110 lb of TNT

10 km30 km60 km120 km N Lake County 29 kmMendocino County 55 kmSonoma County 58 kmColusa County 73 kmGlenn County 85 kmNapa County 87 kmYolo County 108 kmMarin County 112 kmSutter County 118 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
12:56 am PST on 16 December 2020 ()
Where
13 km (8 mi) west of Lakeport, CA · earthquakes near Lakeport
Magnitude
M 2.4 (md)
Depth
3.7 km below the surface
Felt
9 reports · strongest reported intensity IV
Nearest
Lake County, 29 km ENE
Nearest mapped fault
Maacama fault, 2 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 2150 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 20 km (12 mi) from the epicentre. In Lakeport, 13 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: Lakeport 13 km, intensity II · Ukiah 18 km, intensity II · Upper Lake 20 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 110 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.4 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 140,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 99,000× the energy of this one
  3. Around the size people start to feel M 3.0 8.8× the energy of this one
  4. This earthquake M 2.4 about 110 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 5.1 on 2016-08-10 — about 12,000 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 · 10 km NNW 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 39.0312, -123.0667. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Lake County, CA 29 km (18 mi) ENE earthquakes near Lake County
Mendocino County, CA 55 km (34 mi) NW earthquakes near Mendocino County
Sonoma County, CA 58 km (36 mi) SSE earthquakes near Sonoma County
Colusa County, CA 73 km (46 mi) ENE earthquakes near Colusa County
Glenn County, CA 85 km (53 mi) NE earthquakes near Glenn County
Napa County, CA 87 km (54 mi) SE earthquakes near Napa 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. 1.7 4km S of Redwood Valley, CA
  2. 1.8 10km ESE of Willits, CA
  3. 1.6 8km W of Cobb, CA
  4. 1.9 5km W of Cobb, CA
  5. 1.6 8km NW of The Geysers, CA
  6. 1.7 10km SE of Willits, CA
  7. 2.3 8km NNE of Healdsburg, CA
  8. 1.6 3km S of Cobb, CA
  9. 1.7 3km NE of The Geysers, CA
  10. 2.1 2km E of The Geysers, CA
  11. 1.7 8km WSW of Upper Lake, CA
  12. 1.6 10km ESE of Willits, CA
  13. 1.8 3km WNW of Cobb, CA
  14. 1.6 8km WNW of Cobb, CA
  15. 1.7 10km ESE of Redwood Valley, 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.