  In the vast literature on tsunami research, few articles have been devoted to
energy issues. A theoretical investigation on the energy of waves generated by
bottom motion is performed here. We start with the full incompressible Euler
equations in the presence of a free surface and derive both dispersive and
non-dispersive shallow-water equations with an energy equation. It is shown
that dispersive effects only appear at higher order in the energy budget. Then
we solve the Cauchy-Poisson problem of tsunami generation for the linearized
water wave equations. Exchanges between potential and kinetic energies are
clearly revealed.
