2006/10/31 by Armand Wirgin, Wirgin, Armand, Jean‐Philippe Groby +2
Earth and Planetary Sciences · Engineering · Environmental Science · Physics and Astronomy · #Classical Physics (physics.class-ph) #FOS: Physical sciences #Geophysics (physics.geo-ph) #Landslides and related hazards #Seismic Performance and Analysis #Seismic Waves and Analysis #physics.class-ph #physics.geo-ph
paper · pdf · doi:10.48550/arxiv.physics/0610277
soumis a Geophys.J.Intl
arxiv created 2006/10/31 · openalex publication_date 2006/10/31 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We address the problem of the response to a seismic wave of an urban site consisting of a large and infinite number (N_b) of identical, equispaced blocks overlying a soft layer underlain by a hard substratum. The results of the theoretical analysis, appealing to a space-frequency mode-matching (MM) technique, are compared to those obtained by a space-time finite element (FE) method. The two methods are shown to give rise to much the same prediction of seismic response for N_b=10. The MM technique is also applied to the case N_b=∞, notably to reveal the structure and natural frequencies of the vibration modes of the urban site. The mechanism of the interaction between blocks and the ground, as well as that of the collective effects of the blocks, are studied. It is shown that the presence of a large number of blocks modifies the seismic disturbance in a manner which evokes, and may partially account for, what was observed during many earthquakes in Mexico City. Disturbances at a much smaller level, induced by a small number of blocks are studied in the companion paper.