Earthquake · reviewed by a seismologist
M 4.3ml
Port Townsend, WA
Yes. A magnitude 4.3 earthquake was recorded in Port Townsend, WA, 55 km (34 mi) NNW of Seattle, WA, at 7:21 pm PDT on 8 October 2023 (02:21 UTC), 55 km deep. 14,568 people have reported feeling it to USGS.
55 km (34 mi) NNW of Seattle, WA · 41 km (26 mi) WNW of Everett, WA
- When
- Magnitude
- M 4.3 (ml)
- Depth
- 55 km below the surface
- Felt
- 14,568 reports · strongest reported intensity V
- Measured shaking
- intensity IV (ShakeMap)
- USGS impact alert
- green
- Tsunami
- USGS flagged this event for tsunami evaluation. Follow tsunami.gov for official messages.
- Nearest
- Island County, 14 km NNE
- Nearest mapped fault
- Southern Whidbey Island 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 342 days ago
Earthquake alerts for Port Hadlock-Irondale, WA
Get a notification in this browser when USGS records an earthquake near Port Hadlock-Irondale, 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 light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.
At this magnitude and depth, people at rest would likely notice it out to about 109 km (68 mi) from the epicentre. 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: Port Townsend 9 km, intensity III · Coupeville 20 km, intensity III · Camano 21 km, intensity III · Sequim 28 km, intensity III · Oak Harbor 29 km, intensity III · Poulsbo 34 km, intensity III · Edmonds 37 km, intensity III · Lynnwood 39 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 44 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.3 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 3,800× the energy of this one
- Mineral, Virginia 2011 M 5.8 170× the energy of this one
- Magna, Utah 2020 M 5.7 120× the energy of this one
- This earthquake M 4.3 about 44 tons of TNT
- Around the size people start to feel M 3.0 this one released 92× 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.
Where
Epicentre 48.0402, -122.7308. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Island County, WA | 14 km (9 mi) | NNE | earthquakes near Island County |
| Kitsap County, WA | 45 km (28 mi) | S | earthquakes near Kitsap County |
| San Juan County, WA | 59 km (37 mi) | NNW | earthquakes near San Juan County |
| Jefferson County, WA | 65 km (40 mi) | WSW | earthquakes near Jefferson County |
| Snohomish County, WA | 72 km (45 mi) | E | earthquakes near Snohomish County |
| Mason County, WA | 83 km (52 mi) | SSW | earthquakes near Mason County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
56 earthquakes have been recorded within 50 km since this one.
- 1.6 1 km NE of Mill Creek, Washington
- 2.3 7 km ESE of Quilcene, Washington
- 2.2 7 km E of Quilcene, Washington
- 1.5 6 km WNW of Lofall, Washington
- 1.7 5 km WSW of Clinton, Washington
- 1.6 5 km N of Port Townsend, Washington
- 1.8 6 km WSW of Port Hadlock-Irondale, Washington
- 1.7 7 km WSW of Quilcene, Washington
- 1.8 4 km SSW of Port Ludlow, Washington
- 1.6 7 km ESE of Quilcene, Washington
- 1.8 5 km NE of Kingston, Washington
- 1.9 3 km W of Mount Vernon, Washington
- 2.0 9 km W of Coupeville, Washington
- 1.8 4 km NNW of Port Townsend, Washington
- 1.6 4 km SW of Port Ludlow, 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.