Generalized Maslov canonical operator and tsunami asymptotics over nonuniform bottom. I

We suggest a new asymptotic representation for the solutions to the 2-D wave equation with variable velocity with localized initial data. This representation is a generalization of the Maslov canonical operator and gives the formulas for the relationship between initial localized perturbations and wave profiles near the wave fronts including the neighborhood of backtracking (focal or turning) and selfintersection points. We apply these formulas to the problem of a propagation of tsunami waves in the frame of so-called piston model. Finally we suggest the fast asymptotically-numerical algorithm for simulation of tsunami wave over nonuniform bottom. In this first part we present the final formulas and some geometrical construction. The proofs concerning analytical calculations will be done in the second part.