M1.9 earthquake 35 km WSW of Twisp, Washington
A magnitude 1.9 earthquake struck 35 km WSW of Twisp, Washington on Fri, Sep 28, 1990, 7:04 PM PDT (02:04 UTC), 6 km (3 mi) below the surface.
A larger quake followed: M2.8 12 km ENE of Sunnyslope, Washington. This one was a foreshock.
Map
Where this earthquake was located, with the others nearby. Select one for its page.
The earthquake
- Magnitude
- 1.9 (Md, duration), micro
- Magnitude from
- Pacific Northwest Seismic Network
- Local time
- UTC
- 1990-09-29 02:04:01 UTC
- Depth
- 5.6 km (3.5 mi), shallow
- Epicenter
- 48.230° N, 120.556° 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 5.0 km horizontally, 3.3 km in depth
- Magnitude uncertainty
- ±0.08
- Depth from
- From location
- Station coverage gap
- 173°
- Stations used
- 21
Nearest places
Distance and direction from each place to the epicenter, with its forecast.
Nearby
Within 100 km, magnitude 1.5 and up: 8 in the 60 days after this one and 0 in the 30 days before it.
After
- 1.63 km N of Waterville, Washington · 13151 days ago · 5 km deep · 70 km away
- 2.621 km ESE of Darrington, Washington · 13148 days ago · 0 km deep · 57 km away
- 1.640 km WNW of Granite Falls, Washington · 13135 days ago · 7 km deep · 20 km away
- 1.75 km NW of Waterville, Washington · 13133 days ago · 0 km deep · 69 km away
- 2.812 km ENE of Sunnyslope, Washington · 13127 days ago · 11 km deep · 82 km away
- 1.65 km E of Entiat, Washington · 13118 days ago · 3 km deep · 68 km away
- 1.97 km ESE of Marblemount, Washington · 13114 days ago · -1 km deep · 67 km away
- 1.616 km E of Verlot, Washington · 13109 days ago · 1 km deep · 77 km away
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Sources
From the USGS Earthquake Hazards Program and its partner networks, event uw10266728. Read Fri, Oct 2, 2026, 5:49 AM UTC.