Frequency Domain Analysis of Two-Dimensional Wave Propagation with Applications to Earthquake Engineering

A frequency domain analysis is presented for the propagation of SH-waves in a homogeneous two-dimensional medium. Using previously presented boundary element techniques for computing steady-state, harmonic response (1) (2) (3) the admittance function for several points in various geometries is computed for a range of frequencies. These geometries can contain differing topographies and cavities such as hills and tunnels. The incident earthquake is transformed into the frequency domain by a fast Fourier transform (7) , convoluted with the admittance function, and rendered into the time domain. Examples of the technique are given for several different geometries subjected to two different earthquake time histories. The plots presented for these cases show the reasonableness of the results and thereby imply the correctness of the procedure which generated them. An effort is made in understanding the effect of the different topographies and tunnels on wave-scattering patterns.