Simplified vibratory characterization of alluvial basins

Jean-François Semblat (1) , Roberto Paolucci , Anne-Marie Duval (2)

1 IFSTTAR/GER - Département Géotechnique, Eau et Risques
2 ERA 6 Risque sismique - Equipe recherche associée au LCPC - ERA 6 Risque sismique

For the analysis of seismic wave amplification, modal methods are interesting tools to study the modal properties of geological structures. Modal approaches mainly lead to information on such parameters as fundamental frequencies and eigenmodes of alluvial basins. For a specific alluvial deposit in Nice (France), a simplified modal approach involving the Rayleigh method is considered. This approach assumes a set of admissible shape functions for the eigenmodes and allows a fast estimation of the fundamental frequency of the basin. The agreement between modal numerical results and experimental ones is satisfactory. The simplified modal method then appears as an efficient mean for the global vibratory characterization of geological structures towards resonance.

Mots clés: earthquake; site effects; eigenmodes; vibration; resonance; amplification; seismic wave

Domaines: Mécanique des structures [physics.class-ph]; Mécanique des structures [physics.class-ph]

Jean-François Semblat, Roberto Paolucci, Anne-Marie Duval. Simplified vibratory characterization of alluvial basins. Comptes rendus de l’Académie des sciences. Série IIa, Sciences de la terre et des planètes, 2003, 335 (4), pp.365-370. ⟨hal-00614445⟩