This study analyzed seismic wave scattering in the presence of single and double canyons with different geometries and subjected to harmonic SH waves. For this purpose, a three-dimensional boundary element code in the frequency domain was developed and verified. Comprehensive analyses were performed, and the effects of the different parameters were investigated. These parameters are geometry (semi-circular, semi-elliptical, triangular, and trapezoidal), the distance of two adjacent canyons, direction, and frequencies of incident SH waves. The results showed that the interaction of two adjacent canyons is a function of the distance between two canyons and the incident wave frequency. For dimensionless frequency less than 0.1 (g B 0.1), the interaction of the two adjacent canyons could be discarded. For 0:1g B 0.5, no considerable difference for different geometries of two adjacent canyons with the same depth is obtained. Also, it was found that the distance between two canyons, direction, and frequency of the incident waves are the key parameters affecting the ground surface displacements for compound topographies.
