Seismic Wave Amplification in 3D Alluvial Basins: 3D/1D Amplification Ratios from Fast Multipole BEM Simulations

Kristel C MEZA FAJARDO, Jean-François Semblat, Stéphanie Chaillat and 
Luca Lenti
june, 2016
Publication type:
Paper in peer-reviewed journals
Journal:
Bulletin of the Seismological Society of America, vol. 106 (3), pp. 1267-1281
Publisher:
Seismological Society of America
Keywords :
earthquakes; seismology; numerical simulations; seismic waves; site effects; amplification; boundary elements; wave propagation;
Abstract:
In this work, we study seismic wave amplification in alluvial basins having 3D standard geometries through the Fast Multipole Boundary Element Method in the frequency domain. We investigate how much 3D amplification differs from the 1D (horizontal layering) case. Considering incident fields of plane harmonic waves, we examine the relationships between the amplification level and the most relevant physical parameters of the problem (impedance contrast, 3D aspect ratio, vertical and oblique incidence of plane waves). The FMBEM results show that the most important parameters for wave amplification are the impedance contrast and the so-called equivalent shape ratio. Using these two parameters, we derive simple rules to compute the fundamental frequency for various 3D basin shapes and the corresponding 3D/1D amplification factor for 5% damping. Effects on amplification due to 3D basin asymmetry are also studied and incorporated in the derived rules.
BibTeX:
@article{MEZ-Sem-Cha-Len-2016,
    author={Kristel C MEZA FAJARDO and Jean-François Semblat and 
           Stéphanie Chaillat and Luca Lenti },
    title={Seismic Wave Amplification in 3D Alluvial Basins: 3D/1D 
           Amplification Ratios from Fast Multipole BEM Simulations },
    doi={10.1785/0120150159 },
    journal={Bulletin of the Seismological Society of America },
    year={2016 },
    month={6},
    volume={106 (3) },
    pages={1267--1281},
}