Urban seismology: Numerical results and real data observations on the clustering effect of buildings

Abstract

Seismic design parameters for buildings are traditionally based on the seismicity of the area, the so-called site effects, and structural response decoupling with the underlying surface. It is however well known that buildings strongly affect the wavefield interacting in a non-linear way through the foundations and the surrounding soil. In dense urban areas, buildings are very close to each other, and it is reasonable to expect a collective effect known as site-city interaction (SCI). Initially, observations of this phenomenon have been made difficult by the lack of data. Now, the increased availability of continuous records from permanent seismic networks in urban areas or buildings has made SCI an important topic in urban seismology. Here, after presenting some numerical results of SCI in densely built areas, we discuss a recent study on three residential towers located in the city of Grenoble (France) exhibiting an SCI that depends on the strike angle of the seismic energy. Both numerical simulations a...