QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

Earthquake near Upper Lake, CA

No earthquake was likely felt in Upper Lake in the 24 hours to 6:08 am PST (14:08 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 1.8 earthquake was recorded 11 km (7 mi) north of Upper Lake, CA, at 11:21 pm PDT on 10 September 2025 (06:21 UTC), 8.4 km deep.

USGS: 11 km N of Upper Lake, CA

11:21 pm PDT, Sep 10, 2025 · · 8.4 km deep · released about 15 lb of TNT

Every earthquake near Upper Lake Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Lake County 22 kmMendocino County 50 kmGlenn County 57 kmColusa County 58 kmSonoma County 82 kmNapa County 98 kmSutter County 106 kmYolo County 108 kmTehama County 111 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
11:21 pm PDT on 10 September 2025 ()
Where
11 km (7 mi) north of Upper Lake, CA · earthquakes near Upper Lake
Magnitude
M 1.8 (md)
Depth
8.4 km below the surface
Felt
no reports yet
Nearest
Lake County, 22 km SE
Nearest mapped fault
Bartlett Springs fault system, 4 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 427 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 11 km (7 mi) from the epicentre. In Upper Lake, 11 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: Nice, North Lakeport, Lakeport, Redwood Valley, Talmage, Ukiah.

How big was it?

This earthquake released about 15 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 710,000× the energy of this one
  3. Around the size people start to feel M 3.0 63× the energy of this one
  4. This earthquake M 1.8 about 15 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 86,000 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 · 24 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 39.2652, -122.8993. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Lake County, CA 22 km (14 mi) SE earthquakes near Lake County
Mendocino County, CA 50 km (31 mi) WNW earthquakes near Mendocino County
Glenn County, CA 57 km (35 mi) NE earthquakes near Glenn County
Colusa County, CA 58 km (36 mi) E earthquakes near Colusa County
Sonoma County, CA 82 km (51 mi) S earthquakes near Sonoma County
Napa County, CA 98 km (61 mi) SSE earthquakes near Napa County

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

Aftershocks so far

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

  1. 1.6 8 km NW of The Geysers, CA
  2. 1.7 9 km ESE of Willits, CA
  3. 1.6 4 km ESE of Lower Lake, CA
  4. 1.8 4 km ESE of Lower Lake, CA
  5. 2.1 7 km NW of The Geysers, CA
  6. 1.5 8 km NW of The Geysers, CA
  7. 2.4 8 km W of Cobb, CA
  8. 2.3 7 km WNW of Cobb, CA
  9. 1.5 3 km E of Talmage, CA
  10. 1.5 4 km ESE of Lower Lake, CA
  11. 1.7 8 km WNW of Cobb, CA
  12. 1.6 6 km WNW of Cobb, CA
  13. 1.5 8 km NW of The Geysers, CA
  14. 1.6 5 km WNW of Cobb, CA
  15. 1.8 4 km ESE of Talmage, 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.