Strong Ground Motion in the 2011 Tohoku Earthquake : 1 a 1 Directional - 3 Component Modeling


24 Local wave amplification due to strong seismic motions in surficial multilayered soil is 25 influenced by several parameters such as the wavefield polarization and the dynamic properties 26 and impedance contrast between soil layers. The present research aims at investigating seismic 27 motion amplification in the 2011 Tohoku earthquake through a one-directional three-component 28 (1D-3C) wave propagation model. A 3D nonlinear constitutive relation for dry soils under cyclic 29 loading is implemented in a quadratic line finite element model. The soil rheology is modeled by 30 mean of a multi-surface cyclic plasticity model of the Masing-Prandtl-Ishlinskii-Iwan (MPII) 31 type. Its major advantage is that the rheology is characterized by few commonly measured 32 parameters. Ground motions are computed at the surface of soil profiles in the Tohoku area 33 (Japan) by propagating 3C signals recorded at rock outcrops, during the 2011 Tohoku 34 earthquake. Computed surface ground motions are compared to the Tohoku earthquake records 35 at alluvial sites and the reliability of the 1D-3C model is corroborated. The 1D-3C approach is 36 compared with the combination of three separate one-directional analyses of one motion 37 component propagated independently (1D-1C approach). The 3D loading path due to the 3C-38 polarization leads to multiaxial stress interaction that reduces soil strength and increases 39 nonlinear effects. Time histories and spectral amplitudes, for the Tohoku earthquake, are 40 numerically reproduced. The 1D-3C approach allows the evaluation of various parameters of the 41 3C motion and 3D stress and strain evolution all over the soil profile. 42 43 INTRODUCTION 44

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@inproceedings{dAvila2013StrongGM, title={Strong Ground Motion in the 2011 Tohoku Earthquake : 1 a 1 Directional - 3 Component Modeling}, author={Maria Paola Santisi d’Avila and Jean-François Semblat and Luca Matteo Lenti and Maria Paola Santisi and Jean Dieudonne}, year={2013} }