The passage of elastic waves through an anomalous region-I. Geophys

The discussion of the transmission of plane harmonic elastic waves through a layer of material in which the elastic properties vary in a complex way is continued. In Parts I and I1 of this series, the method of Schwinger and Levine was examined and the accuracy of the solutions was tested. So that this preliminary discussion would not be obscured by detail, only normal incidence of the wave onto the layer was dealt with. In this paper we apply the method of Schwinger and Levine to the general problem of oblique incidence of plane dilatational or shear waves. Furthermore, we derive expressions leading to approximations to the amplitudes of the reflected as well as the transmitted waves. The rcs-triction that, in the layer, the elastic properties of the material vary in the normal direction only is retained. 1