M3.9 earthquake 27 km S of Greenwater, Washington
A magnitude 3.9 earthquake struck 27 km S of Greenwater, Washington on Thu, Apr 17, 1975, 9:57 PM PDT (04:57 UTC), 4 km (2 mi) below the surface.
A larger quake followed: M4.2 2 km SW of DuPont, Washington. This one was a foreshock.
Map
Where this earthquake was located, with the others nearby. Select one for its page.
The earthquake
- Magnitude
- 3.9 (md), minor
- Local time
- UTC
- 1975-04-18 04:57:56 UTC
- Depth
- 4.0 km (2.5 mi), shallow
- Epicenter
- 46.911° N, 121.597° W
- Region
- Washington
- Tsunami flag
- No
- Status
- Reviewed by a seismologist
Did you feel it?
No one has reported feeling this quake to the USGS.
How well it is located
Reviewed by a seismologist.
- Location uncertainty
- About 2.9 km horizontally, 1.0 km in depth
- Magnitude uncertainty
- ±0.06
- Depth from
- From location
- Station coverage gap
- 232°, poorly surrounded by stations
- Stations used
- 11
Nearest places
Distance and direction from each place to the epicenter, with its forecast.
Nearby
Within 100 km, magnitude 1.5 and up: 5 in the 60 days after this one and 7 in the 30 days before it.
After
- 1.929 km SSE of Greenwater, Washington · 18785 days ago · 1 km deep · 3 km away
- 4.22 km SW of DuPont, Washington · 18780 days ago · 45 km deep · 83 km away
- 1.71 km NNE of Snoqualmie, Washington · 18752 days ago · 8 km deep · 72 km away
- 1.55 km S of Fall City, Washington · 18748 days ago · 18 km deep · 71 km away
- 1.92 km N of White Center, Washington · 18737 days ago · 22 km deep · 90 km away
Before
- 2.128 km S of Greenwater, Washington · 18788 days ago · 2 km deep · 1 km away
- 2.327 km S of Greenwater, Washington · 18792 days ago · 1 km deep · 1 km away
- 2.817 km ESE of Carbonado, Washington · 18793 days ago · -1 km deep · 23 km away
- 3.711 km SW of Greenwater, Washington · 18793 days ago · 6 km deep · 22 km away
- 2.22 km NNE of Riverton, Washington · 18801 days ago · 25 km deep · 84 km away
- 2.13 km NE of Dash Point, Washington · 18804 days ago · 14 km deep · 76 km away
- 2.83 km NW of Black Diamond, Washington · 18815 days ago · 20 km deep · 57 km away
Earthquakes todayWashington earthquakesLive radar here
Sources
From the USGS Earthquake Hazards Program and its partner networks, event uw10860713 (also filed as usp0000ans). Read Tue, Sep 22, 2026, 10:00 AM UTC.