Non-seismic tsunamis

An initial tsunami profile has many components of different periods which propagate with different velocities. This difference in velocity, although very small, results in non-negligible deformations in the wave profile if the travel time becomes long, as in the case of a distant tsunami. A parameter Pa is used to judge whether or not these frequency dependent dispersion effects should be included  

If the water is deeper than 200 m, the linear long wave equation should be applied. For the region shallower than 200 m, the shallow water theory with a term for bottom friction included should be used. This shallow water theory includes the first order approximation of the amplitude dependent dispersion. Under special conditions, the term for frequency dependent dispersion should be included. If the purpose of the simulation is to determine the runup height, the equations of higher order approximations are not necessary. 

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