QuakeIndex

Earthquake · reviewed by a seismologist

M 2.0md

Earthquake near Williams, CA

No earthquake was likely felt in Williams in the 24 hours to 4:17 am PST (12:17 UTC). The last one was M 4.0, 79 km (49 mi) WNW, at 5:01 am PDT on 28 October 2026, estimated intensity II (weak) in town; 14 felt reports to USGS. Every earthquake near Williams

This page: a magnitude 2.0 earthquake was recorded 19 km (12 mi) west-southwest of Williams, CA, at 9:04 am PDT on 17 March 2018 (16:04 UTC), 2.8 km deep.

USGS: 19km WSW of Williams, CA

9:04 am PDT, Mar 17, 2018 · · 2.8 km deep · released about 26 lb of TNT

10 km30 km60 km120 km N Colusa County 13 kmLake County 33 kmGlenn County 54 kmSutter County 58 kmYolo County 63 kmNapa County 68 kmSonoma County 81 kmButte County 90 kmYuba County 90 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
9:04 am PDT on 17 March 2018 ()
Where
19 km (12 mi) west-southwest of Williams, CA · earthquakes near Williams
Magnitude
M 2.0 (md)
Depth
2.8 km below the surface
Felt
no reports yet
Nearest
Colusa County, 13 km ENE
Nearest mapped fault
Great Valley thrust fault system, 7 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 3157 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 15 km (9 mi) from the epicentre. In Williams, 19 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: Maxwell, Clearlake Oaks, Clearlake, Arbuckle.

How big was it?

This earthquake released about 26 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.0 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 580,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 410,000× the energy of this one
  3. Around the size people start to feel M 3.0 36× the energy of this one
  4. This earthquake M 2.0 about 26 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 50,000 times the energy of this one.

Before 2016, the USGS record since 1900 lists no earthquake of M5 or more within 50 km.

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 39.1138, -122.3668. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Colusa County, CA 13 km (8 mi) ENE earthquakes near Colusa County
Lake County, CA 33 km (20 mi) W earthquakes near Lake County
Glenn County, CA 54 km (34 mi) N earthquakes near Glenn County
Sutter County, CA 58 km (36 mi) E earthquakes near Sutter County
Yolo County, CA 63 km (39 mi) SE earthquakes near Yolo County
Napa County, CA 68 km (42 mi) S earthquakes near Napa County

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

Aftershocks so far

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

  1. 1.5 6km W of Cobb, CA
  2. 1.8 6km NW of The Geysers, CA
  3. 1.7 5km W of Cobb, CA
  4. 1.5 4km W of Cobb, CA
  5. 1.7 4km W of Cobb, CA
  6. 1.7 9km E of Hidden Valley Lake, CA
  7. 2.7 6km NW of The Geysers, CA
  8. 2.0 1km E of The Geysers, CA
  9. 1.5 5km WNW of Cobb, CA
  10. 1.9 9km WNW of Cobb, CA
  11. 1.9 4km NW of The Geysers, CA
  12. 1.6 17km SE of Lake Pillsbury, CA
  13. 1.6 3km W of Cobb, CA
  14. 1.6 17km NNE of Nice, CA
  15. 2.0 6km 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.