A numerical model of the generation and transoceanic propagation of tsunamis is developed. The model is based on hydrodynamic equations in a spherical coordinate system to account for the spherical nature of the Earth. The model provides a deterministic approach to the description of tsunami waves, and is verified by hindcasting the wave behavior following the Alaskan earthquake of 1964. Results of the computation are compared with field measurements (Wake Island deep-water gage records and results obtained from the numerical model developed previously by Hwang and Divoky, 1970). From these calculations, the excessive damage at Crescent City, California, seems to have resulted in part from the phenomenon of tsunami directionality. Finally, the model is applied to a hypothetical CANNIKIN source (Rat Islands source) and shows that the resulting tsunami energy radiation pattern would be highly directional with the largest wave heights passing through the west-central Pacific.