QuakeIndex

Earthquake · reviewed by a seismologist

M 2.9ml

Earthquake near Monroe, WA

No earthquake was likely felt in Monroe in the 24 hours to 8:15 am PST (16:15 UTC). The last one was M 4.2, 76 km (47 mi) SW, at 2:05 pm PDT on 29 September 2026, estimated intensity II (weak) in town; 9,329 felt reports to USGS. Every earthquake near Monroe

This page: a magnitude 2.9 earthquake was recorded 5 km (3 mi) south of Monroe, WA, at 2:41 am PST on 28 December 2020 (10:41 UTC), 26 km deep. 182 people have reported feeling it to USGS.

USGS: 4 km S of Monroe, Washington

36 km (22 mi) NE of Seattle, WA · 18 km (11 mi) ENE of Bothell, WA

2:41 am PST, Dec 28, 2020 · · 26 km deep · released about 650 lb of TNT

10 km30 km60 km120 km N Snohomish County 31 kmKing County 37 kmKitsap County 55 kmIsland County 65 kmSkagit County 76 kmPierce County 86 kmChelan County 101 kmMason County 104 kmSan Juan County 114 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
2:41 am PST on 28 December 2020 ()
Where
5 km (3 mi) south of Monroe, WA · earthquakes near Monroe
Magnitude
M 2.9 (ml)
Depth
26 km below the surface
Felt
182 reports · strongest reported intensity IV
Measured shaking
intensity III (ShakeMap)
Nearest
Snohomish County, 31 km NNE
Nearest mapped fault
Southern Whidbey Island fault, under 1 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 1985 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 18 km (11 mi) from the epicentre. In Monroe, 5 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.

Likely felt in: Monroe 5 km, intensity II · North Creek 16 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 650 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 23,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 16,000× the energy of this one
  3. Around the size people start to feel M 3.0 1.5× the energy of this one
  4. This earthquake M 2.9 about 650 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 4.6 on 2019-07-12 — about 340 times the energy of this one.

Before 2016, the USGS record lists 3 earthquakes of M5 or more within 50 km:

  1. 5.4 8 km NNE of Lake Marcel-Stillwater, Washington · 9 km SE of this epicentre
  2. 5.2 9 km NE of Lake Marcel-Stillwater, Washington · 12 km SE of this epicentre
  3. 5.0 4 km ENE of Machias, Washington · 21 km N 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 47.8132, -121.9667. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Snohomish County, WA 31 km (19 mi) NNE earthquakes near Snohomish County
King County, WA 37 km (23 mi) SSE earthquakes near King County
Kitsap County, WA 55 km (34 mi) WSW earthquakes near Kitsap County
Island County, WA 65 km (40 mi) NW earthquakes near Island County
Skagit County, WA 76 km (48 mi) N earthquakes near Skagit County
Pierce County, WA 86 km (53 mi) S earthquakes near Pierce County

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

Aftershocks so far

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

  1. 1.8 1 km SW of Snoqualmie, Washington
  2. 1.7 2 km E of Lake Stevens, Washington
  3. 1.6 1 km ESE of Issaquah, Washington
  4. 1.6 2 km ENE of Granite Falls, Washington
  5. 1.5 1 km ENE of Bainbridge Island, Washington
  6. 1.9 2 km NNE of Esperance, Washington
  7. 2.3 0 km SSW of Boulevard Park, Washington
  8. 2.2 1 km NNE of Carnation, Washington
  9. 1.5 1 km N of Boulevard Park, Washington
  10. 1.7 3 km ENE of Granite Falls, Washington
  11. 1.7 6 km ENE of Lake Roesiger, Washington
  12. 1.7 1 km NNE of Woods Creek, Washington
  13. 1.6 0 km N of Boulevard Park, Washington
  14. 2.8 0 km S of Boulevard Park, Washington
  15. 2.1 0 km SSW of Boulevard Park, 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.