The seismic response of shallow alluvial valleys using a simplified model

A simplified model is used to approximately simulate the seismic response of three-dimensional shallow alluvial valleys. It is constructed from the exact solution for a simple configuration. Namely, the antiplane response of a rectangular deposit with a moving rigid base. In such solution, which is used as a framework for our approximations, the spectral signature of locally generater surface waves is explicit. Thus an approximate expression is constructed to separately account for 1D response and lateral effects. Results are presented for two- and three - dimensional cases. Comparisons are provided with rigorous solutions. Our formulas allow for fast computations (AU)