QuakeIndex

Earthquake · reviewed by a seismologist

M 1.5md

Earthquake near Lakeport, CA

No earthquake was likely felt in Lakeport in the 24 hours to 10:36 pm PST (06:36 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 1.5 earthquake was recorded 3 km (2 mi) east-northeast of Lakeport, CA, at 10:31 am PDT on 1 August 2017 (17:31 UTC), 20 km deep.

USGS: 3 km ENE of Lakeport, California

10:31 am PDT, Aug 1, 2017 · · 20 km deep · released about 5.9 lb of TNT

10 km30 km60 km120 km N Lake County 13 kmColusa County 57 kmSonoma County 58 kmMendocino County 65 kmGlenn County 74 kmNapa County 77 kmYolo County 94 kmSutter County 102 kmMarin County 112 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
10:31 am PDT on 1 August 2017 ()
Where
3 km (2 mi) east-northeast of Lakeport, CA · earthquakes near Lakeport
Magnitude
M 1.5 (md)
Depth
20 km below the surface
Felt
no reports yet
Nearest
Lake County, 13 km ENE
Nearest mapped fault
Big Valley fault, 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 3382 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth it was probably too small to be felt, even directly above it. In Lakeport, 3 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, Nice, Kelseyville, Soda Bay, Upper Lake, Clear Lake Riviera.

How big was it?

This earthquake released about 5.9 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 2,500,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,800,000× the energy of this one
  3. Around the size people start to feel M 3.0 160× the energy of this one
  4. This earthquake M 1.5 about 5.9 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 220,000 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 · 20 km WNW 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 39.0498, -122.8792. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Lake County, CA 13 km (8 mi) ENE earthquakes near Lake County
Colusa County, CA 57 km (36 mi) ENE earthquakes near Colusa County
Sonoma County, CA 58 km (36 mi) S earthquakes near Sonoma County
Mendocino County, CA 65 km (40 mi) NW earthquakes near Mendocino County
Glenn County, CA 74 km (46 mi) NNE earthquakes near Glenn County
Napa County, CA 77 km (48 mi) SE earthquakes near Napa County

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

Aftershocks so far

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

  1. 1.9 4 km W of Cobb, California
  2. 1.8 6 km W of Cobb, California
  3. 1.7 Northern California
  4. 1.8 18 km E of Potter Valley, California
  5. 1.7 5 km S of Cobb, California
  6. 1.6 5 km WNW of Cobb, California
  7. 1.6 5 km SSW of Cobb, California
  8. 1.9 4 km SSW of Cobb, California
  9. 1.6 5 km SSW of Cobb, California
  10. 1.7 10 km ENE of Talmage, California
  11. 1.9 8 km W of Cobb, California
  12. 1.8 5km NW of The Geysers, CA
  13. 2.1 6 km WSW of Cobb, California
  14. 1.6 7km NW of The Geysers, CA
  15. 1.6 1km NNW 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.