QuakeIndex

Earthquake · reviewed by a seismologist

M 2.7ml

Earthquake near Fall City, WA

No earthquake was likely felt in Fall City in the 24 hours to 3:53 pm PST (23:53 UTC). The last one was M 4.2, 65 km (41 mi) WSW, at 2:05 pm PDT on 29 September 2026, estimated intensity II (weak) in town; 9,329 felt reports to USGS. Every earthquake near Fall City

This page: a magnitude 2.7 earthquake was recorded 6 km (4 mi) northeast of Fall City, WA, at 9:20 am PST on 9 January 2020 (17:20 UTC), 15 km deep. 34 people have reported feeling it to USGS.

USGS: 5 km NE of Fall City, Washington

39 km (24 mi) E of Seattle, WA · 15 km (9 mi) E of Sammamish, WA

9:20 am PST, Jan 9, 2020 · · 15 km deep · released about 330 lb of TNT

10 km30 km60 km120 km N King County 13 kmSnohomish County 50 kmKitsap County 61 kmPierce County 66 kmIsland County 87 kmChelan County 95 kmSkagit County 99 kmKittitas County 102 kmMason 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
9:20 am PST on 9 January 2020 ()
Where
6 km (4 mi) northeast of Fall City, WA · earthquakes near Fall City
Magnitude
M 2.7 (ml)
Depth
15 km below the surface
Felt
34 reports · strongest reported intensity II
Nearest
King County, 13 km S
Nearest mapped fault
Rattlesnake Mountain fault, 5 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 2416 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 20 km (12 mi) from the epicentre. In Fall City, 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.

Likely felt in: Fall City 6 km, intensity II · Snoqualmie 9 km, intensity II · City of Sammamish 15 km, intensity II · Issaquah 17 km, intensity II · Sammamish 19 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 330 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 46,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 33,000× the energy of this one
  3. Around the size people start to feel M 3.0 2.9× the energy of this one
  4. This earthquake M 2.7 about 330 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 680 times the energy of this one.

Before 2016, the USGS record lists 4 earthquakes of M5 or more within 50 km:

  1. 5.4 8 km NNE of Lake Marcel-Stillwater, Washington · 17 km N of this epicentre
  2. 5.2 9 km NE of Lake Marcel-Stillwater, Washington · 16 km N of this epicentre
  3. 5.0 4 km ENE of Machias, Washington · 45 km NNW of this epicentre
  4. 5.0 3 km WSW of Des Moines, Washington · 47 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 47.6070, -121.8353. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
King County, WA 13 km (8 mi) S earthquakes near King County
Snohomish County, WA 50 km (31 mi) N earthquakes near Snohomish County
Kitsap County, WA 61 km (38 mi) W earthquakes near Kitsap County
Pierce County, WA 66 km (41 mi) SSW earthquakes near Pierce County
Island County, WA 87 km (54 mi) NW earthquakes near Island County
Chelan County, WA 95 km (59 mi) ENE earthquakes near Chelan County

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

Aftershocks so far

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

  1. 2.9 4 km S of Monroe, Washington
  2. 2.0 2 km N of North Bend, Washington
  3. 2.0 2 km NE of Black Diamond, Washington
  4. 2.8 2 km S of Ravensdale, Washington
  5. 1.5 13 km W of Greenwater, Washington
  6. 1.5 12 km W of Greenwater, Washington
  7. 1.7 7 km ENE of Fall City, Washington
  8. 2.6 3 km WSW of Monroe, Washington
  9. 1.7 6 km NE of Mirrormont, Washington
  10. 1.5 3 km WSW of Wilderness Rim, Washington
  11. 2.0 2 km W of Union Hill-Novelty Hill, Washington
  12. 1.9 3 km N of White Center, Washington
  13. 2.1 Washington
  14. 1.8 2 km WSW of Shoreline, Washington
  15. 2.5 3 km W of Monroe, 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.