QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6ml

Earthquake near Sudden Valley, WA

No earthquake was likely felt in Sudden Valley in the 24 hours to 12:35 am PST (08:35 UTC). The last one was M 3.8, 52 km (32 mi) SSW, at 11:35 pm PDT on 1 July 2026, estimated intensity II (weak) in town; 2,030 felt reports to USGS. Every earthquake near Sudden Valley

This page: a magnitude 1.6 earthquake was recorded 7 km (5 mi) northeast of Sudden Valley, WA, at 2:36 am PDT on 12 August 2020 (09:36 UTC), 20 km deep.

USGS: 7 km NE of Sudden Valley, Washington

13 km (8 mi) ENE of Bellingham, WA · 129 km (80 mi) N of Seattle, WA

2:36 am PDT, Aug 12, 2020 · · 20 km deep · released about 6.4 lb of TNT

10 km30 km60 km120 km N Whatcom County 34 kmSkagit County 47 kmSan Juan County 67 kmIsland County 74 kmSnohomish County 89 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
2:36 am PDT on 12 August 2020 ()
Where
7 km (5 mi) northeast of Sudden Valley, WA · earthquakes near Sudden Valley
Magnitude
M 1.6 (ml)
Depth
20 km below the surface
Felt
no reports yet
Nearest
Whatcom County, 34 km ENE
Nearest mapped fault
Boulder Creek-Canyon Creek fault, 18 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 2284 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 Sudden Valley, 7 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: Geneva, Bellingham, Everson, Nooksack, Marietta-Alderwood, Peaceful Valley.

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 2 earthquakes of M5 or more within 50 km:

  1. 6.0 San Juan Islands, Washington · 38 km WSW of this epicentre
  2. 5.0 4 km ENE of Deming, Washington · 12 km NE 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 48.7772, -122.2908. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Whatcom County, WA 34 km (21 mi) ENE earthquakes near Whatcom County
Skagit County, WA 47 km (29 mi) SE earthquakes near Skagit County
San Juan County, WA 67 km (42 mi) WSW earthquakes near San Juan County
Island County, WA 74 km (46 mi) SSW earthquakes near Island County
Snohomish County, WA 89 km (55 mi) SSE earthquakes near Snohomish County
Clallam County, WA 139 km (87 mi) WSW earthquakes near Clallam County

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

Aftershocks so far

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

  1. 1.7 2 km ESE of Burlington, Washington
  2. 1.7 10 km NNE of Hamilton, Washington
  3. 2.2 9 km N of Hamilton, Washington
  4. 2.2 3 km ESE of Burlington, Washington
  5. 2.9 8 km NNE of Hamilton, Washington
  6. 2.1 8 km NNE of Hamilton, Washington
  7. 2.4 9 km NNE of Hamilton, Washington
  8. 2.4 9 km NNE of Hamilton, Washington
  9. 1.6 10 km NNE of Hamilton, Washington
  10. 2.0 9 km N of Hamilton, Washington
  11. 2.6 8 km NNE of Hamilton, Washington
  12. 2.5 9 km NNE of Hamilton, Washington
  13. 1.6 9 km NNE of Hamilton, Washington
  14. 2.8 9 km NNE of Hamilton, Washington
  15. 1.9 9 km NNE of Hamilton, Washington

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.