QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7md

Earthquake near North Lakeport, CA

No earthquake was likely felt in North Lakeport in the 24 hours to 11:57 pm PST (07:57 UTC). The last one was M 1.8, 12 km (8 mi) NW, at 10:36 am PST on 5 November 2026, estimated intensity II (weak) in town. Every earthquake near North Lakeport

This page: a magnitude 1.7 earthquake was recorded 2 km (1 mi) southwest of North Lakeport, CA, at 3:45 pm PDT on 4 May 2020 (22:45 UTC), 6.9 km deep. 4 people have reported feeling it to USGS.

USGS: 2km SW of North Lakeport, CA

3:45 pm PDT, May 4, 2020 · · 6.9 km deep · released about 10 lb of TNT

10 km30 km60 km120 km N Lake County 16 kmMendocino County 59 kmColusa County 61 kmSonoma County 61 kmGlenn County 74 kmNapa County 82 kmYolo County 99 kmSutter County 106 kmMarin County 115 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
3:45 pm PDT on 4 May 2020 ()
Where
2 km (1 mi) southwest of North Lakeport, CA · earthquakes near North Lakeport
Magnitude
M 1.7 (md)
Depth
6.9 km below the surface
Felt
4 reports · strongest reported intensity III
Nearest
Lake County, 16 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 2379 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 10 km (6 mi) from the epicentre. In North Lakeport, 2 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: Lakeport 4 km, intensity II · Upper Lake 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 10 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 1,500,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,100,000× the energy of this one
  3. Around the size people start to feel M 3.0 95× the energy of this one
  4. This earthquake M 1.7 about 10 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 130,000 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 · 15 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 39.0763, -122.9273. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Lake County, CA 16 km (10 mi) ENE earthquakes near Lake County
Mendocino County, CA 59 km (37 mi) NW earthquakes near Mendocino County
Colusa County, CA 61 km (38 mi) E earthquakes near Colusa County
Sonoma County, CA 61 km (38 mi) S earthquakes near Sonoma County
Glenn County, CA 74 km (46 mi) NE earthquakes near Glenn County
Napa County, CA 82 km (51 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. 1.5 1km NNW of The Geysers, CA
  2. 1.6 2km W of Anderson Springs, CA
  3. 1.5 7km NW of The Geysers, CA
  4. 2.1 8km NW of The Geysers, CA
  5. 2.1 7km NW of The Geysers, CA
  6. 1.6 3km SW of Anderson Springs, CA
  7. 1.6 3km SW of Anderson Springs, CA
  8. 1.8 3km SW of Anderson Springs, CA
  9. 2.0 6km NW of The Geysers, CA
  10. 1.8 7km NW of The Geysers, CA
  11. 1.8 8km E of Cloverdale, CA
  12. 1.7 2km ESE of The Geysers, CA
  13. 1.6 3km SW of Anderson Springs, CA
  14. 1.8 3km SE of The Geysers, CA
  15. 1.7 9km WNW of Cobb, 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.