QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6md

Earthquake near Ukiah, CA

Yes: an earthquake was likely felt in Ukiah in the last 24 hours. M 1.5, 10 km (6 mi) NE of Ukiah, at 12:31 pm PST on 11 November 2026 (20:31 UTC); the estimated shaking in Ukiah was intensity II (weak). Every earthquake near Ukiah

This page: a magnitude 1.6 earthquake was recorded 23 km (14 mi) southwest of Ukiah, CA, at 5:48 am PDT on 4 May 2017 (12:48 UTC), less than 1 km deep.

USGS: 3 km SSE of Philo, California

90 km (56 mi) NW of Santa Rosa, CA

5:48 am PDT, May 4, 2017 · · -0.5 km deep · released about 6.4 lb of TNT

10 km30 km60 km120 km N Mendocino County 44 kmLake County 59 kmSonoma County 71 kmColusa County 104 kmGlenn County 108 kmNapa 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
5:48 am PDT on 4 May 2017 ()
Where
23 km (14 mi) southwest of Ukiah, CA · earthquakes near Ukiah
Magnitude
M 1.6 (md)
Depth
-0.5 km below the surface
Felt
no reports yet
Nearest
Mendocino County, 44 km N
Nearest mapped fault
San Andreas fault, 21 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 3478 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 Ukiah, 23 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: Boonville 6 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 6.4 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 2,400,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,700,000× the energy of this one
  3. Around the size people start to feel M 3.0 150× the energy of this one
  4. This earthquake M 1.6 about 6.4 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

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

Before 2016, the USGS record lists one earthquake of M5 or more within 50 km:

  1. 5.2 6 km ESE of Talmage, California · 30 km ENE 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 39.0348, -123.4247. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Mendocino County, CA 44 km (27 mi) N earthquakes near Mendocino County
Lake County, CA 59 km (37 mi) E earthquakes near Lake County
Sonoma County, CA 71 km (44 mi) SE earthquakes near Sonoma County
Colusa County, CA 104 km (64 mi) E earthquakes near Colusa County
Glenn County, CA 108 km (67 mi) NE earthquakes near Glenn County
Napa County, CA 112 km (70 mi) ESE earthquakes near Napa County

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

Aftershocks so far

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

  1. 2.5 7 km NNE of Hopland, California
  2. 1.8 9 km W of Hopland, California
  3. 1.6 6 km W of Sea Ranch, California
  4. 3.9 3 km NW of Redwood Valley, California
  5. 1.6 5 km E of Point Arena, California
  6. 1.5 9 km NE of Willits, California
  7. 1.8 3 km WSW of Hopland, California
  8. 1.6 8 km E of Willits, California
  9. 2.0 6 km ENE of Calpella, California
  10. 1.7 9 km ESE of Willits, California
  11. 1.7 1 km N of Talmage, California
  12. 2.2 12 km WSW of Hopland, California
  13. 2.1 10 km ESE of Hopland, California
  14. 1.5 7 km ESE of Hopland, California
  15. 1.7 10 km ENE of Talmage, California

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.