QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7ml

Earthquake near Bainbridge Island, WA

No earthquake was likely felt in Bainbridge Island in the 24 hours to 7:21 am PST (15:21 UTC). The last one was M 4.2, 29 km (18 mi) SSW, at 2:05 pm PDT on 29 September 2026, estimated intensity III (weak) in town; 9,329 felt reports to USGS. Every earthquake near Bainbridge Island

This page: a magnitude 1.7 earthquake was recorded 2 km (1 mi) east-northeast of Bainbridge Island, WA, at 12:43 pm PDT on 30 September 2021 (19:43 UTC), 15 km deep. 2 people have reported feeling it to USGS.

USGS: 2 km ENE of Bainbridge Island, Washington

11 km (7 mi) W of Seattle, WA

12:43 pm PDT, Sep 30, 2021 · · 15 km deep · released about 11 lb of TNT

10 km30 km60 km120 km N Kitsap County 12 kmKing County 52 kmIsland County 60 kmMason County 60 kmPierce County 70 kmSnohomish County 72 kmJefferson County 80 kmThurston County 82 kmSan Juan County 107 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
12:43 pm PDT on 30 September 2021 ()
Where
2 km (1 mi) east-northeast of Bainbridge Island, WA · earthquakes near Bainbridge Island
Magnitude
M 1.7 (ml)
Depth
15 km below the surface
Felt
2 reports · strongest reported intensity II
Nearest
Kitsap County, 12 km W
Nearest mapped fault
Seattle fault, 3 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 614 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 Bainbridge Island, 2 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: Manchester, Enetai, Suquamish, Tracyton, Seattle, Bremerton.

How big was it?

This earthquake released about 11 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,400,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,000,000× the energy of this one
  3. Around the size people start to feel M 3.0 89× the energy of this one
  4. This earthquake M 1.7 about 11 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

The largest earthquake within 50 km since 2016 was M 4.6 on 2019-07-12 — about 21,000 times the energy of this one.

Before 2016, the USGS record lists 6 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.7 1 km ENE of Dash Point, Washington · 35 km S of this epicentre
  2. 6.1 Puget Sound region, Washington · 32 km SW of this epicentre
  3. 5.8 Puget Sound area, Washington · 50 km SW of this epicentre
  4. 5.4 8 km NNE of Lake Marcel-Stillwater, Washington · 48 km ENE of this epicentre
  5. 5.3 Eastern Olympic Peninsula, Washington · 42 km WNW 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 47.6337, -122.4942. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Kitsap County, WA 12 km (7 mi) W earthquakes near Kitsap County
King County, WA 52 km (32 mi) ESE earthquakes near King County
Island County, WA 60 km (37 mi) NNW earthquakes near Island County
Mason County, WA 60 km (37 mi) WSW earthquakes near Mason County
Pierce County, WA 70 km (43 mi) SSE earthquakes near Pierce County
Snohomish County, WA 72 km (45 mi) NE earthquakes near Snohomish County

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

Aftershocks so far

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

  1. 1.6 Puget Sound region, Washington
  2. 1.5 7 km WNW of Lofall, Washington
  3. 1.8 2 km SSE of Lake Forest Park, Washington
  4. 1.9 7 km SSW of Port Ludlow, Washington
  5. 1.9 7 km WNW of Lofall, Washington
  6. 2.3 5 km WNW of Wauna, Washington
  7. 1.5 8 km WNW of Lofall, Washington
  8. 3.7 7 km WNW of Lofall, Washington
  9. 1.5 5 km W of Gorst, Washington
  10. 1.7 6 km E of Quilcene, Washington
  11. 1.6 5 km SW of Port Ludlow, Washington
  12. 1.8 6 km NNW of Kingston, Washington
  13. 1.5 6 km WSW of Erlands Point-Kitsap Lake, Washington
  14. 1.8 3 km W of Hansville, Washington
  15. 2.4 3 km W of Hansville, 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.