Nonstationary interference wave fields of the $SV$-type in a free elastic layer and a problem of the ultrasonic modeling of plane seismic fields on plate-like models

The problem of a quantitative study of wave fields in a free elastic layer excited by point nonstationary sources is discussed.
The principal attention is paid to a low-frequency part of the Fourier spectrum. Roots of the dispersion equation of the layer chosen in the Lambe method representation are studied very thoroughly. On this basis efficient methods for a quontitative estimation of the wave interference modes are elaborated. It allows us essentially to advance a mathematical justification of the methods of the seismic modeling of the plane wave fields on the plate-like models. Bibl. 8 titles, ill. 24.