September 4, 1989 Tsunami: Semidi Islands, AK, United States
A tsunami caused by a magnitude 7.1 earthquake began at Semidi Islands, AK, United States on September 4, 1989 at 13:14:58 UTC. The water rose as high as 0.1 meters. Its effects were recorded at 2 places.
Where the waves reached
The source (white) and every runup with a place, colored by the water height recorded there. A ring is a runup NCEI marks doubtful.
- Under 1 m
- 1 to 3 m
- 3 to 10 m
- 10 to 30 m
- 30 m and more
- Height not recorded
The tsunami
- Date
- September 4, 1989, 13:14:58 UTC
- Source
- Semidi Islands, AK, United States
- Cause
- Earthquake
- Earthquake
- Magnitude 7.1, 11 km deep
- Maximum water height
- 0.1 m (0.3 ft)
- Runups recorded
- 2
- Tsunami magnitude (Iida)
- -3.3
- Waters
- Ocean
- How certain
- Definite tsunami
- Source location
- 55.543° N, 156.835° W
The toll
The record gives no deaths, injuries or damage for this tsunami.
Every runup
Nearest the source first. Heights are above sea level at the time; a tide gauge reads half the wave’s full height.
| Where | Country | Km from source | Water height, m | Inland, m | Measured by | First wave, UTC | Deaths |
|---|---|---|---|---|---|---|---|
| Sand Point, AK, AK | United States | 233 | 0.1 | Tide gauge (half the maximum wave height) | |||
| Unalaska, Dutch Harbor, AK, AK | United States | 651 | Eyewitness observation of water height |
More
Every tsunami in 1989The 1900sTsunamis of United StatesThe earthquakeThis day in weather historyAlerts in force
Sources
Tsunami events and runups from NOAA’s National Centers for Environmental Information, Global Historical Hazard Database, cited as NCEI/WDS, doi:10.7289/V5PN93H7. Public domain. Read 2026-09-24. NCEI tsunami event 2187.