QuakeIndex

Earthquake · reviewed by a seismologist

M 2.6md

Earthquake near Upper Lake, CA

No earthquake was likely felt in Upper Lake in the 24 hours to 11:03 pm PST (07:03 UTC). The last one was M 1.6, 8 km (5 mi) W, at 4:31 am PST on 10 November 2026, estimated intensity II (weak) in town. Every earthquake near Upper Lake

This page: a magnitude 2.6 earthquake was recorded 17 km (11 mi) northeast of Upper Lake, CA, at 2:20 pm PDT on 24 July 2020 (21:20 UTC), 13 km deep. 1 person has reported feeling it to USGS.

USGS: 17km NE of Upper Lake, CA

2:20 pm PDT, Jul 24, 2020 · · 13 km deep · released about 270 lb of TNT

10 km30 km60 km120 km N Lake County 17 kmColusa County 46 kmGlenn County 49 kmMendocino County 62 kmSonoma County 83 kmNapa County 92 kmSutter County 94 kmYolo County 98 kmTehama County 106 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
2:20 pm PDT on 24 July 2020 ()
Where
17 km (11 mi) northeast of Upper Lake, CA · earthquakes near Upper Lake
Magnitude
M 2.6 (md)
Depth
13 km below the surface
Felt
1 report · strongest reported intensity II
Nearest
Lake County, 17 km S
Nearest mapped fault
Bartlett Springs fault system, 3 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 2231 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 20 km (12 mi) from the epicentre. In Upper Lake, 17 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: Upper Lake 17 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 270 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 57,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 40,000× the energy of this one
  3. Around the size people start to feel M 3.0 3.6× the energy of this one
  4. This earthquake M 2.6 about 270 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 4,900 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 · 34 km WSW 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 39.2628, -122.7560. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Lake County, CA 17 km (11 mi) S earthquakes near Lake County
Colusa County, CA 46 km (28 mi) ESE earthquakes near Colusa County
Glenn County, CA 49 km (30 mi) NE earthquakes near Glenn County
Mendocino County, CA 62 km (39 mi) WNW earthquakes near Mendocino County
Sonoma County, CA 83 km (52 mi) S earthquakes near Sonoma County
Napa County, CA 92 km (57 mi) SSE earthquakes near Napa 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. 2.2 12km NNW of Redwood Valley, CA
  2. 2.0 10km ESE of Willits, CA
  3. 1.6 10km ESE of Willits, CA
  4. 2.1 10km ESE of Willits, CA
  5. 2.3 10km ESE of Willits, CA
  6. 2.6 10km ESE of Willits, CA
  7. 2.2 10km ESE of Willits, CA
  8. 1.8 10km ESE of Willits, CA
  9. 2.3 9km ESE of Willits, CA
  10. 2.3 10km ESE of Willits, CA
  11. 1.7 10km ESE of Willits, CA
  12. 2.9 10km ESE of Willits, CA
  13. 3.9 11km ESE of Willits, CA
  14. 2.1 10km ESE of Willits, CA
  15. 1.8 10km ESE of Willits, 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.