QuakeIndex

Earthquake · reviewed by a seismologist

M 1.5md

Earthquake near Upper Lake, CA

No earthquake was likely felt in Upper Lake in the 24 hours to 1:35 am PST (09:35 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 1.5 earthquake was recorded 9 km (6 mi) west-northwest of Upper Lake, CA, at 6:26 pm PDT on 27 May 2026 (01:26 UTC), 7.7 km deep.

USGS: 9 km WNW of Upper Lake, CA

87 km (54 mi) NNW of Santa Rosa, CA

6:26 pm PDT, May 27, 2026 · · 7.7 km deep · released about 5.4 lb of TNT

Every earthquake near Upper Lake Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Lake County 25 kmMendocino County 46 kmColusa County 67 kmGlenn County 69 kmSonoma County 75 kmNapa County 97 kmYolo County 111 kmSutter County 114 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
6:26 pm PDT on 27 May 2026 ()
Where
9 km (6 mi) west-northwest of Upper Lake, CA · earthquakes near Upper Lake
Magnitude
M 1.5 (md)
Depth
7.7 km below the surface
Felt
no reports yet
Nearest
Lake County, 25 km ESE
Nearest mapped fault
Maacama fault, 15 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 157 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 6 km (4 mi) from the epicentre. In Upper Lake, 9 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.

Earthquakes near other towns within 30 km: North Lakeport, Talmage, Nice, Ukiah, Lakeport, Redwood Valley.

How big was it?

This earthquake released about 5.4 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,800,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 2,000,000× the energy of this one
  3. Around the size people start to feel M 3.0 180× the energy of this one
  4. This earthquake M 1.5 about 5.4 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 240,000 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 · 11 km SW 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 39.1927, -123.0095. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Lake County, CA 25 km (15 mi) ESE earthquakes near Lake County
Mendocino County, CA 46 km (28 mi) NW earthquakes near Mendocino County
Colusa County, CA 67 km (41 mi) E earthquakes near Colusa County
Glenn County, CA 69 km (43 mi) NE earthquakes near Glenn County
Sonoma County, CA 75 km (46 mi) S earthquakes near Sonoma County
Napa County, CA 97 km (60 mi) SE earthquakes near Napa County

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

Aftershocks so far

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

  1. 2.0 14 km S of Willits, CA
  2. 2.0 11 km NW of The Geysers, CA
  3. 1.7 5 km NNW of The Geysers, CA
  4. 1.6 11 km WNW of Cobb, CA
  5. 1.6 12 km NNE of Redwood Valley, CA
  6. 2.7 9 km NW of The Geysers, CA
  7. 2.0 9 km NW of The Geysers, CA
  8. 1.6 5 km W of Cobb, CA
  9. 2.0 11 km WNW of Cobb, CA
  10. 1.9 11 km WNW of Cobb, CA
  11. 2.3 11 km WNW of Cobb, CA
  12. 1.6 6 km WNW of Cobb, CA
  13. 1.5 2 km WNW of The Geysers, CA
  14. 2.1 11 km NW of The Geysers, CA
  15. 1.7 11 km 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.