Showing papers by "Ajit Mal published in 1965"

Scattering of Love waves by a constriction in the crust

Abstract: A perturbation technique is applied to a study of the propagation of Love waves in a layer of nonuniform thickness lying over a half-space. The layer is assumed to have a plane free surface while the interface protrudes into it in a certain finite region. Love waves are generated by a point source on the free surface of the crust at a distance from the inhomogeneity. A simple but rigorous derivation is given for the scattering of the waves incident at the inhomogeneity. The theory is applicable for any shape of the inhomogeneity. Numerical calculations for the particular case in which the height of the perturbation is constant throughout a finite length indicate mode conversion in the constricted region. There is essentially a phase shift in the same mode; the superposition of the converted modes, however, gives rise to amplitude perturbation in every mode. The results are fairly accurate as long as the height of the inhomogeneity is small in comparison with the wavelength of the incident waves. By suitable interpretation of the results, the theory is extended to include the case in which the area of the perturbed region is large. Although only the scalar problem has been considered, the theory can be extended to treat the vector case without much difficulty.