QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

Earthquake near Tanner, WA

No earthquake was likely felt in Tanner in the 24 hours to 6:31 am PST (14:31 UTC). The last one was M 2.6, 9 km (6 mi) SW, at 6:09 pm PDT on 14 October 2026, estimated intensity II (weak) in town; 46 felt reports to USGS. Every earthquake near Tanner

This page: a magnitude 1.8 earthquake was recorded 8 km (5 mi) east of Tanner, WA, at 12:35 pm PDT on 10 April 2021 (19:35 UTC), 15 km deep.

USGS: 8 km E of Tanner, Washington

56 km (35 mi) ESE of Seattle, WA · 33 km (21 mi) ESE of Sammamish, WA

12:35 pm PDT, Apr 10, 2021 · · 15 km deep · released about 17 lb of TNT

10 km30 km60 km120 km N King County 15 kmPierce County 60 kmSnohomish County 66 kmKitsap County 78 kmKittitas County 82 kmChelan County 88 kmThurston County 107 kmIsland County 109 kmLewis 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
12:35 pm PDT on 10 April 2021 ()
Where
8 km (5 mi) east of Tanner, WA · earthquakes near Tanner
Magnitude
M 1.8 (ml)
Depth
15 km below the surface
Felt
no reports yet
Nearest
King County, 15 km WNW
Nearest mapped fault
Rattlesnake Mountain fault, 9 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 613 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 Tanner, 8 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: Riverbend, Wilderness Rim, North Bend, Snoqualmie, Fall City, Hobart.

How big was it?

This earthquake released about 17 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 5.8 900,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 640,000× the energy of this one
  3. Around the size people start to feel M 3.0 57× the energy of this one
  4. This earthquake M 1.8 about 17 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. 5.4 8 km NNE of Lake Marcel-Stillwater, Washington · 37 km NNW of this epicentre
  2. 5.2 9 km NE of Lake Marcel-Stillwater, Washington · 35 km NNW 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 47.4637, -121.6407. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
King County, WA 15 km (9 mi) WNW earthquakes near King County
Pierce County, WA 60 km (37 mi) SW earthquakes near Pierce County
Snohomish County, WA 66 km (41 mi) N earthquakes near Snohomish County
Kitsap County, WA 78 km (49 mi) WNW earthquakes near Kitsap County
Kittitas County, WA 82 km (51 mi) ESE earthquakes near Kittitas County
Chelan County, WA 88 km (55 mi) ENE earthquakes near Chelan County

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

Aftershocks so far

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

  1. 1.7 15 km SW of Easton, Washington
  2. 2.1 5 km SW of Black Diamond, Washington
  3. 1.6 6 km SW of Sultan, Washington
  4. 1.6 Washington
  5. 1.5 Washington
  6. 2.0 Washington
  7. 3.1 6 km SSE of Black Diamond, Washington
  8. 1.9 12 km ESE of Enumclaw, Washington
  9. 1.9 2 km E of Union Hill-Novelty Hill, Washington
  10. 1.6 Washington
  11. 1.8 1 km W of Redmond, Washington
  12. 1.6 11 km SSW of Gold Bar, Washington
  13. 1.5 13 km W of Greenwater, Washington
  14. 2.4 7 km ENE of Fall City, Washington
  15. 2.0 7 km NE of Fall City, 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.