On April 1, 1946 CE, a major tsunami was generated in the Aleutian Islands region following a powerful earthquake near Unimak Island, Alaska. According to the National Oceanic and Atmospheric Administration's National Centers for Environmental Information (NOAA/NCEI) Global Historical Tsunami Database, the event caused widespread damage and loss of life across the Pacific basin, with significant runup documented along nearby coastlines.
Earthquake Source and Event Chronology
The tsunami was triggered by an earthquake recorded at 12:29:01.3 UTC on April 1, 1946 CE. The seismic event had a recorded magnitude of 8.6 and was centered at latitude 53.492 and longitude -162.832 in the coastal waters off Unimak Island, Alaska. The database assigns the event a tsunami validity rating of 4, confirming it as a definite tsunami caused by seismic activity (cause code 3).
Wave Measurements and Coastal Impact
The sea waves generated by the seismic disturbance produced dramatic coastal flooding. The highest recorded maximum water height listed in the official record reached 42.0 meters near the source area. This maximum height reflects extreme local runup along exposed shorelines rather than a uniform ocean-wide wave height.
The physical impacts extended far from the epicenter, leading to catastrophic coastal flooding in several Pacific regions:
- Fatalities: The event resulted in 168 confirmed deaths.
- Economic Damage: Total monetary damage was recorded at 26.271 million USD.
- Maximum Water Height: A peak water runup of 42.0 meters was documented in historical surveys.
Scientific Record and Historical Context
In global natural hazard catalogs, the April 1, 1946 event remains an important benchmark for understanding trans-oceanic tsunami risks generated by subduction zone earthquakes in the North Pacific. The NOAA/NCEI Global Historical Tsunami Database maintains detailed event parameters (catalog event ID 1762) to assist researchers in tsunami hydrodynamic modeling, risk assessment, and coastal safety planning.
Frequently asked questions
When did the 1946 Unimak Island tsunami occur?
The tsunami was generated on April 1, 1946 CE, following an earthquake recorded at 12:29:01.3 UTC near Unimak Island, Alaska.
What was the magnitude of the earthquake associated with the tsunami?
The earthquake associated with the tsunami had a recorded magnitude of 8.6.
What was the maximum water height recorded for the 1946 Unimak Island tsunami?
The official database records a maximum water height of 42.0 meters.
What were the human and financial impacts of the 1946 tsunami?
The event caused 168 deaths and approximately 26.271 million USD in recorded property damage.
Sources and further context
Official datasets support the event-specific facts.