QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7md

Earthquake near Upper Lake, CA

No earthquake was likely felt in Upper Lake in the 24 hours to 4:14 am PST (12:14 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 1.7 earthquake was recorded 6 km (4 mi) southwest of Upper Lake, CA, at 9:51 am PDT on 2 September 2019 (16:51 UTC), less than 1 km deep.

USGS: 6km SW of Upper Lake, CA

9:51 am PDT, Sep 2, 2019 · · -0.6 km deep · released about 11 lb of TNT

10 km30 km60 km120 km N Lake County 19 kmMendocino County 54 kmColusa County 63 kmSonoma County 67 kmGlenn County 71 kmNapa County 88 kmYolo County 104 kmSutter County 109 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
9:51 am PDT on 2 September 2019 ()
Where
6 km (4 mi) southwest of Upper Lake, CA · earthquakes near Upper Lake
Magnitude
M 1.7 (md)
Depth
-0.6 km below the surface
Felt
no reports yet
Nearest
Lake County, 19 km E
Nearest mapped fault
Big Valley fault, 9 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 2618 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 12 km (7 mi) from the epicentre. In Upper Lake, 6 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 6 km, intensity II · Lakeport 10 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 11 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,400,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 970,000× the energy of this one
  3. Around the size people start to feel M 3.0 86× the energy of this one
  4. This earthquake M 1.7 about 11 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 120,000 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 · 12 km W 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 39.1285, -122.9608. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Lake County, CA 19 km (12 mi) E earthquakes near Lake County
Mendocino County, CA 54 km (33 mi) NW earthquakes near Mendocino County
Colusa County, CA 63 km (39 mi) E earthquakes near Colusa County
Sonoma County, CA 67 km (42 mi) S earthquakes near Sonoma County
Glenn County, CA 71 km (44 mi) NE earthquakes near Glenn County
Napa County, CA 88 km (55 mi) SE 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. 1.6 3km SW of Anderson Springs, CA
  2. 2.1 6km W of Cobb, CA
  3. 1.5 4km NW of The Geysers, CA
  4. 1.5 6km NW of The Geysers, CA
  5. 2.4 4km WNW of Cobb, CA
  6. 1.6 4km SSE of The Geysers, CA
  7. 1.7 3km SW of Anderson Springs, CA
  8. 1.7 14km NE of Upper Lake, CA
  9. 1.5 6km WNW of Cobb, CA
  10. 2.6 7km W of Cobb, CA
  11. 2.4 9km NW of The Geysers, CA
  12. 2.8 9km WNW of Cobb, CA
  13. 2.0 7km NW of The Geysers, CA
  14. 1.9 18km NE of Upper Lake, CA
  15. 1.5 6km WNW 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.