Earthquake · reviewed by a seismologist
M 3.9ml
Earthquake near Snoqualmie, WA
No earthquake was likely felt in Snoqualmie in the 24 hours to 2:23 am PST (10:23 UTC). The last one was M 2.6, 12 km (8 mi) S, at 6:09 pm PDT on 14 October 2026, estimated intensity II (weak) in town; 46 felt reports to USGS. Every earthquake near Snoqualmie
This page: a magnitude 3.9 earthquake was recorded 9 km (6 mi) north-northeast of Snoqualmie, WA, at 3:17 am PDT on 8 August 2023 (10:17 UTC), 16 km deep. 1,585 people have reported feeling it to USGS.
USGS: 9 km NNE of Snoqualmie, Washington
43 km (27 mi) E of Seattle, WA · 20 km (12 mi) E of Sammamish, WA
- When
- 3:17 am PDT on 8 August 2023 ()
- Where
- 9 km (6 mi) north-northeast of Snoqualmie, WA · earthquakes near Snoqualmie
- Magnitude
- M 3.9 (ml)
- Depth
- 16 km below the surface
- Felt
- 1,585 reports · strongest reported intensity IV
- Measured shaking
- intensity IV (ShakeMap)
- Nearest
- King County, 13 km SSW
- Nearest mapped fault
- Rattlesnake Mountain fault, 8 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 569 days ago
Earthquake alerts for Snoqualmie, WA
Get a notification in this browser when USGS records an earthquake near Snoqualmie, WA. No account or email needed.
Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
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 89 km (55 mi) from the epicentre. In Snoqualmie, 9 km away, the estimate is intensity III (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 9 km, intensity III · Fall City 10 km, intensity III · City of Sammamish 20 km, intensity III · Issaquah 21 km, intensity III · Sammamish 23 km, intensity III · West Lake Sammamish 25 km, intensity III · Redmond 27 km, intensity III · Maple Valley 31 km, intensity III. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 11 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.9 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 15,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 680× the energy of this one
- Magna, Utah 2020 M 5.7 480× the energy of this one
- This earthquake M 3.9 about 11 tons of TNT
- Around the size people start to feel M 3.0 this one released 23× more
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 10 times the energy of this one.
Before 2016, the USGS record lists 3 earthquakes of M5 or more within 50 km:
- 5.4 8 km NNE of Lake Marcel-Stillwater, Washington · 19 km NNW of this epicentre
- 5.2 9 km NE of Lake Marcel-Stillwater, Washington · 17 km NNW of this epicentre
- 5.0 4 km ENE of Machias, Washington · 47 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 47.6040, -121.7720. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| King County, WA | 13 km (8 mi) | SSW | earthquakes near King County |
| Snohomish County, WA | 50 km (31 mi) | N | earthquakes near Snohomish County |
| Kitsap County, WA | 66 km (41 mi) | W | earthquakes near Kitsap County |
| Pierce County, WA | 68 km (42 mi) | SSW | earthquakes near Pierce County |
| Chelan County, WA | 91 km (56 mi) | ENE | earthquakes near Chelan County |
| Island County, WA | 91 km (57 mi) | NW | earthquakes near Island County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
57 earthquakes have been recorded within 50 km since this one.
- 1.6 10 km NNE of Snoqualmie, Washington
- 2.5 10 km NE of Snoqualmie, Washington
- 1.7 3 km N of Woods Creek, Washington
- 1.9 11 km NE of Snoqualmie, Washington
- 1.5 5 km WSW of Black Diamond, Washington
- 1.9 3 km SSE of Woods Creek, Washington
- 1.6 4 km N of Woods Creek, Washington
- 2.2 3 km SW of Redmond, Washington
- 2.7 2 km E of Redmond, Washington
- 2.0 6 km NE of Snoqualmie, Washington
- 1.5 7 km NNE of Lake Marcel-Stillwater, Washington
- 2.3 1 km S of Fall City, Washington
- 1.6 2 km S of Sultan, Washington
- 1.8 2 km NW of Duvall, Washington
- 1.6 14 km N of Snoqualmie Pass, 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
- The official USGS event page — the source of record for every value above
- Did you feel it? Report it to USGS — reports go to USGS, not to us
- ShakeMap for this event, when USGS has produced one
QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.