Spectral integral representations of volume scattering in sediments in layered waveguides

In situ measurements of scattering strength are often obtained by analyzing the early-time, high-angle reverberation from bottom and subbottom features. In order to provide insight into the mechanisms which cause bottom reverberation, and to their distinguishing characteristics, it is necessary to have a capability for modeling both the rough surface and the volume scattering mechanisms. For high-angle, early-time backscatter, the most appropriate approach is to use a spectral integral representation, which naturally includes the continuous spectrum important for this angular regime. A rough surface scattering theory developed earlier in this framework has provided important insights into wave scattering and penetration physics at the seafloor. Here a consistent representation for the subbottom scattering is developed and examples are provided which illustrate the observable differences between the two scattering mechanisms.