abstract
In this paper we investigate the two-dimensional diffraction problem associated with the propagation of plane harmonic Love waves, normally incident (from either side) upon the plane of discontinuity in the horizontally discontinuous structure consisting of welded layered quarter-spaces with a plane surface. Formulas for complex reflection and transmission coefficients are obtained for the plane-wave approximation, and their variational improvement is sought through the Schwinger-Levine variational principle in such a way so as to incorporate the contributions caused by body-wave conversion. Numerical computation of the results, under both approximations, indicates that when the impedance contrast across the lateral discontinuity becomes large, the amplitude of the transmitted wave from the hard medium into the soft one can be amplified by more than an order of magnitude at certain frequencies for geologically reasonable structures, and the results may, therefore, be useful in earthquake engineering.
