Seismic Motion in Urban Sites

by J.-P. Groby & A. Wirgin arXiv.org E-print Archive, 26 Sep 2006 We address the problem of the response to a seismic wave of an urban site consisting of N non-identical, non-equispaced blocks overlying a soft layer underlain by a hard substratum. The results of a theoretical analysis, appealing to a space-frequency mode-matching technique, are compared to those obtained by a space-time finite element technique. The two methods are shown to give rise to the same prediction of the seismic response for N=1 and N=2 blocks. The mechanism of the interaction between blocks and the ground, as well as that of the mutual interaction between blocks, are studied. It is shown that the presence of a small number of blocks modifies the seismic disturbance in a manner which evokes qualitatively, but not quantitatively, what was observed during the 1985 Michoacan earthquake in Mexico City. Read more