QuakeIndex

Earthquake · reviewed by a seismologist

M 2.2ml

Earthquake near Big Lake, WA

No earthquake was likely felt in Big Lake in the 24 hours to 8:37 am PST (16:37 UTC). The last one was M 2.6, 5 km (3 mi) WNW, at 9:17 pm PDT on 11 September 2026, estimated intensity II (weak) in town; 10 felt reports to USGS. Every earthquake near Big Lake

This page: a magnitude 2.2 earthquake was recorded 6 km (3 mi) east of Big Lake, WA, at 9:32 pm PDT on 29 July 2021 (04:32 UTC), 18 km deep. 2 people have reported feeling it to USGS.

USGS: 5 km E of Big Lake, Washington

87 km (54 mi) N of Seattle, WA · 35 km (22 mi) N of Marysville, WA

9:32 pm PDT, Jul 29, 2021 · · 18 km deep · released about 54 lb of TNT

Every earthquake near Big Lake Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Skagit County 28 kmIsland County 46 kmSnohomish County 48 kmWhatcom County 55 kmSan Juan County 70 kmKitsap County 91 kmKing County 104 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
9:32 pm PDT on 29 July 2021 ()
Where
6 km (3 mi) east of Big Lake, WA · earthquakes near Big Lake
Magnitude
M 2.2 (ml)
Depth
18 km below the surface
Felt
2 reports · strongest reported intensity III
Nearest
Skagit County, 28 km ENE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 613 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 4 km (2 mi) from the epicentre. In Big Lake, 6 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: Clear Lake, Mount Vernon, Sedro-Woolley, Burlington, Bryant, Arlington.

How big was it?

This earthquake released about 54 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.2 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 280,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 200,000× the energy of this one
  3. Around the size people start to feel M 3.0 18× the energy of this one
  4. This earthquake M 2.2 about 54 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. 5.0 4 km ENE of Machias, Washington · 46 km SSE of this epicentre
  2. 5.0 6 km W of Conway, Washington · 21 km WSW 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 48.3950, -122.1677. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Skagit County, WA 28 km (17 mi) ENE earthquakes near Skagit County
Island County, WA 46 km (28 mi) SW earthquakes near Island County
Snohomish County, WA 48 km (30 mi) SE earthquakes near Snohomish County
Whatcom County, WA 55 km (34 mi) NNE earthquakes near Whatcom County
San Juan County, WA 70 km (44 mi) W earthquakes near San Juan County
Kitsap County, WA 91 km (57 mi) SSW earthquakes near Kitsap County

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

Aftershocks so far

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

  1. 2.1 6 km NNW of La Conner, Washington
  2. 1.5 1 km NNW of Granite Falls, Washington
  3. 3.6 2 km E of Mount Vernon, Washington
  4. 1.9 1 km WNW of Mount Vernon, Washington
  5. 1.7 1 km ESE of Acme, Washington
  6. 1.6 2 km ENE of Granite Falls, Washington
  7. 2.0 4 km W of Lake Cavanaugh, Washington
  8. 1.7 1 km NNW of Silvana, Washington
  9. 1.6 2 km E of Granite Falls, Washington
  10. 1.8 2 km ENE of Granite Falls, Washington
  11. 2.0 8 km NE of Granite Falls, Washington
  12. 1.6 2 km ENE of Granite Falls, Washington
  13. 1.9 8 km ENE of Port Townsend, Washington
  14. 2.0 4 km SE of Swede Heaven, Washington
  15. 2.1 7 km W of Lake Cavanaugh, 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.