QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

9 km NNE of Rockport, Washington

· 4.9 km deep · released about 15 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Skagit County 20 kmWhatcom County 37 kmSnohomish County 58 kmIsland County 93 kmChelan County 105 kmSan Juan 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
Magnitude
M 1.8 (ml)
Depth
4.9 km below the surface
Felt
no reports yet
Nearest
Skagit County, 20 km WSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 775 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

How big was it?

This earthquake released about 15 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 1,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 710,000× the energy of this one
  3. Around the size people start to feel M 3.0 63× the energy of this one
  4. This earthquake M 1.8 about 15 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.

Where

Epicentre 48.5642, -121.5675. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Skagit County, WA 20 km (12 mi) ENE of here earthquakes near Skagit County
Whatcom County, WA 37 km (23 mi) SSE of here earthquakes near Whatcom County
Snohomish County, WA 58 km (36 mi) NNE of here earthquakes near Snohomish County
Island County, WA 93 km (58 mi) ENE of here earthquakes near Island County
Chelan County, WA 105 km (65 mi) NW of here earthquakes near Chelan County
San Juan County, WA 113 km (70 mi) E of here earthquakes near San Juan County

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

Aftershocks so far

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

  1. 1.1 6 km NE of Oso, Washington
  2. 0.7 6 km SSE of Concrete, Washington
  3. 1.6 3 km WSW of Lake Cavanaugh, Washington
  4. 1.8 15 km ESE of Acme, Washington
  5. 1.9 7 km SSE of Concrete, Washington
  6. 1.9 2 km NNE of Lyman, Washington
  7. 1.7 3 km N of Lyman, Washington
  8. 2.2 2 km N of Lyman, Washington
  9. 1.7 1 km WNW of Marblemount, Washington
  10. 2.5 4 km WSW of Concrete, Washington
  11. 2.2 4 km WSW of Concrete, Washington
  12. 1.8 4 km WSW of Concrete, Washington
  13. 2.5 3 km WSW of Concrete, Washington
  14. 2.1 15 km ESE of Acme, Washington
  15. 2.3 3 km NNW of Glacier, 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.