QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

Earthquake near Big Lake, WA

No earthquake was likely felt in Big Lake in the 24 hours to 11:38 pm PST (07:38 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 1.8 earthquake was recorded 3 km (2 mi) south-southwest of Big Lake, WA, at 11:18 am PDT on 24 August 2019 (18:18 UTC), 20 km deep. 1 person has reported feeling it to USGS.

USGS: 3 km SSW of Big Lake, Washington

84 km (52 mi) N of Seattle, WA · 34 km (21 mi) NNW of Marysville, WA

11:18 am PDT, Aug 24, 2019 · · 20 km deep · released about 14 lb of TNT

10 km30 km60 km120 km N Skagit County 35 kmIsland County 39 kmSnohomish County 51 kmWhatcom County 60 kmSan Juan County 64 kmKitsap County 87 kmKing County 103 kmJefferson County 113 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
11:18 am PDT on 24 August 2019 ()
Where
3 km (2 mi) south-southwest of Big Lake, WA · earthquakes near Big Lake
Magnitude
M 1.8 (ml)
Depth
20 km below the surface
Felt
1 report · strongest reported intensity II
Nearest
Skagit County, 35 km ENE
Nearest mapped fault
Utsalady Point 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 2561 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 Big Lake, 3 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: Mount Vernon, Clear Lake, Burlington, Sedro-Woolley, Bryant, Stanwood.

How big was it?

This earthquake released about 14 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,100,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 760,000× the energy of this one
  3. Around the size people start to feel M 3.0 68× the energy of this one
  4. This earthquake M 1.8 about 14 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 · 14 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 48.3763, -122.2603. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Skagit County, WA 35 km (22 mi) ENE earthquakes near Skagit County
Island County, WA 39 km (24 mi) SW earthquakes near Island County
Snohomish County, WA 51 km (32 mi) SE earthquakes near Snohomish County
Whatcom County, WA 60 km (38 mi) NNE earthquakes near Whatcom County
San Juan County, WA 64 km (40 mi) WNW earthquakes near San Juan County
Kitsap County, WA 87 km (54 mi) SSW earthquakes near Kitsap County

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

Aftershocks so far

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

  1. 1.6 0 km S of Big Lake, Washington
  2. 1.7 3 km WSW of Lake Cavanaugh, Washington
  3. 1.7 3 km E of Granite Falls, Washington
  4. 1.6 6 km SSE of Oso, Washington
  5. 1.9 7 km ENE of Port Townsend, Washington
  6. 2.0 6 km SE of Bay View, Washington
  7. 2.2 5 km NE of Oak Harbor, Washington
  8. 1.8 4 km ENE of Granite Falls, Washington
  9. 1.8 6 km WNW of Coupeville, Washington
  10. 2.1 6 km SE of Oso, Washington
  11. 1.7 5 km NNE of Anacortes, Washington
  12. 2.3 5 km N of Anacortes, Washington
  13. 2.5 5 km N of Anacortes, WA
  14. 1.8 3 km ENE of Granite Falls, Washington
  15. 1.9 4 km W of Mount Vernon, 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.