QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6ml

Earthquake near Bremerton, WA

No earthquake was likely felt in Bremerton in the 24 hours to 8:30 am PST (16:30 UTC). The last one was M 4.2, 20 km (12 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 Bremerton

This page: a magnitude 1.6 earthquake was recorded 37 km (23 mi) west of Bremerton, WA, at 7:03 am PST on 28 December 2017 (15:03 UTC), 44 km deep.

USGS: 19 km WSW of Brinnon, Washington

58 km (36 mi) W of Seattle, WA

7:03 am PST, Dec 28, 2017 · · 44 km deep · released about 6.6 lb of TNT

10 km30 km60 km120 km N Mason County 27 kmKitsap County 36 kmJefferson County 38 kmIsland County 71 kmGrays Harbor County 75 kmThurston County 77 kmClallam County 81 kmPierce County 95 kmKing County 98 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
7:03 am PST on 28 December 2017 ()
Where
37 km (23 mi) west of Bremerton, WA · earthquakes near Bremerton
Magnitude
M 1.6 (ml)
Depth
44 km below the surface
Felt
no reports yet
Nearest
Mason County, 27 km S
Nearest mapped fault
Saddle Mountain faults, 9 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 3241 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 Bremerton, 37 km away, the estimate is intensity I (not felt). 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: Seabeck, Belfair.

How big was it?

This earthquake released about 6.6 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,300,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,600,000× the energy of this one
  3. Around the size people start to feel M 3.0 140× the energy of this one
  4. This earthquake M 1.6 about 6.6 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 4.1 on 2017-02-23 — about 6,200 times the energy of this one.

Before 2016, the USGS record lists 4 earthquakes of M5 or more within 50 km:

  1. 6.1 Puget Sound region, Washington · 35 km SE of this epicentre
  2. 5.8 Puget Sound area, Washington · 39 km SSE of this epicentre
  3. 5.3 Eastern Olympic Peninsula, Washington · 25 km NNE of this epicentre
  4. 5.1 Olympic Peninsula, Washington · 49 km SSW 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 47.5948, -123.1252. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Mason County, WA 27 km (17 mi) S earthquakes near Mason County
Kitsap County, WA 36 km (22 mi) E earthquakes near Kitsap County
Jefferson County, WA 38 km (24 mi) NW earthquakes near Jefferson County
Island County, WA 71 km (44 mi) NNE earthquakes near Island County
Grays Harbor County, WA 75 km (47 mi) SW earthquakes near Grays Harbor County
Thurston County, WA 77 km (48 mi) SSE earthquakes near Thurston County

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

Aftershocks so far

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

  1. 1.7 20 km W of Brinnon, Washington
  2. 2.6 3 km WSW of Erlands Point-Kitsap Lake, Washington
  3. 2.7 35 km NE of Amanda Park, Washington
  4. 1.9 1 km N of Enetai, Washington
  5. 2.0 0 km ESE of Erlands Point-Kitsap Lake, Washington
  6. 1.8 1 km NNE of Burley, Washington
  7. 1.7 6 km SSE of Port Ludlow, Washington
  8. 2.1 19 km ENE of Amanda Park, Washington
  9. 1.6 9 km NNE of Quilcene, Washington
  10. 2.3 1 km NNE of Enetai, Washington
  11. 2.8 8 km SW of Skokomish, Washington
  12. 1.8 7 km ESE of Quilcene, Washington
  13. 1.7 6 km W of Lofall, Washington
  14. 1.9 3 km SSE of Port Ludlow, Washington
  15. 2.3 15 km SW of River Road, 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.