QuakeIndex

Earthquake · reviewed by a seismologist

M 2.8ml

Earthquake near Tanner, WA

No earthquake was likely felt in Tanner in the 24 hours to 4:02 am PST (12:02 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 2.8 earthquake was recorded 11 km (7 mi) east of Tanner, WA, at 12:38 am PDT on 10 April 2021 (07:38 UTC), 11 km deep. 211 people have reported feeling it to USGS.

USGS: 11 km E of Tanner, Washington

59 km (37 mi) ESE of Seattle, WA · 36 km (23 mi) ESE of Sammamish, WA

12:38 am PDT, Apr 10, 2021 · · 11 km deep · released about 480 lb of TNT

10 km30 km60 km120 km N King County 18 kmPierce County 62 kmSnohomish County 67 kmKittitas County 79 kmKitsap County 81 kmChelan County 86 kmThurston County 110 kmIsland County 112 kmLewis 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
12:38 am PDT on 10 April 2021 ()
Where
11 km (7 mi) east of Tanner, WA · earthquakes near Tanner
Magnitude
M 2.8 (ml)
Depth
11 km below the surface
Felt
211 reports · strongest reported intensity III
Measured shaking
intensity II (ShakeMap)
Nearest
King County, 18 km W
Nearest mapped fault
Rattlesnake Mountain fault, 12 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 1972 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 25 km (16 mi) from the epicentre. In Tanner, 11 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: Snoqualmie 19 km, intensity II · Fall City 25 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 480 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 32,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 22,000× the energy of this one
  3. Around the size people start to feel M 3.0 2× the energy of this one
  4. This earthquake M 2.8 about 480 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 · 39 km NNW of this epicentre
  2. 5.2 9 km NE of Lake Marcel-Stillwater, Washington · 37 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 47.4602, -121.5968. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
King County, WA 18 km (11 mi) W earthquakes near King County
Pierce County, WA 62 km (38 mi) SW earthquakes near Pierce County
Snohomish County, WA 67 km (42 mi) N earthquakes near Snohomish County
Kittitas County, WA 79 km (49 mi) ESE earthquakes near Kittitas County
Kitsap County, WA 81 km (51 mi) WNW earthquakes near Kitsap County
Chelan County, WA 86 km (53 mi) ENE earthquakes near Chelan County

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

Aftershocks so far

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

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