QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1md

4km W of Ukiah, CA

· -0.6 km deep · released about 37 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Mendocino County 35 kmLake County 45 kmSonoma County 75 kmColusa County 88 kmGlenn County 90 kmNapa County 108 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
Magnitude
M 2.1 (md)
Depth
-0.6 km below the surface
Felt
5 reports · strongest reported intensity IV
Nearest
Mendocino County, 35 km NNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1308 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 5 people have reported feeling it to USGS.

How big was it?

This earthquake released about 37 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 410,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 290,000× the energy of this one
  3. Around the size people start to feel M 3.0 26× the energy of this one
  4. This earthquake M 2.1 about 37 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.

Where

Epicentre 39.1477, -123.2613. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Mendocino County, CA 35 km (22 mi) SSE of here earthquakes near Mendocino County
Lake County, CA 45 km (28 mi) W of here earthquakes near Lake County
Sonoma County, CA 75 km (47 mi) NNW of here earthquakes near Sonoma County
Colusa County, CA 88 km (55 mi) W of here earthquakes near Colusa County
Glenn County, CA 90 km (56 mi) SW of here earthquakes near Glenn County
Napa County, CA 108 km (67 mi) NW of here earthquakes near Napa County

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

Aftershocks so far

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

  1. 1.9 14km SE of Lake Pillsbury, CA
  2. 1.7 14km SE of Lake Pillsbury, CA
  3. 2.8 6km ESE of Lake Pillsbury, CA
  4. 1.5 5km W of Ukiah, CA
  5. 1.6 6km SE of Lake Pillsbury, CA
  6. 2.7 6km ESE of Lake Pillsbury, CA
  7. 1.9 4km E of Lake Pillsbury, CA
  8. 1.5 8km NNW of Redwood Valley, CA
  9. 1.7 5km W of Ukiah, CA
  10. 2.2 10km ESE of Redwood Valley, CA
  11. 1.5 5km W of Ukiah, CA
  12. 1.7 4km SE of Redwood Valley, CA
  13. 1.6 4km S of Boonville, CA
  14. 1.6 4km W of Ukiah, CA
  15. 1.5 7km NNW of Redwood Valley, 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.

For this area

The largest earthquake within 50 km in our catalogue was M 5.1 on 2016-08-10 — it released about 35,000 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.