Predictions of kumamoto ground motion from linear and nonlinear 2d simulation in the framework of egs step 2 and step 3 blind test

Abstract

We present the results of 2D numerical simulation carried out using FLAC3D-7.0. The model geometry has been derived by the seismic section provided by the ESGG6 organizing committee (CMPM) and by the Japan Integrated Velocity Structure Model (JIVSM). The seismic velocity model and density were derived from the 1D preferred model proposed by CMPM for the units filling the Kumamoto Plain, and from the JIVSM for the Mount Kinbo area. We have performed an elastic simulation for Step2, while for Step3, in addition to a linear elastic simulation, a non-linear elasto-plastic simulation has been run using the Mohr-Coulomb constitutive law to characterize some shallow layers. For Step3 linear and nonlinear synthetics waveforms are almost identical, likely due to the mechanical parameters and the constitutive model chosen being not able to induce non-linear effects. Synthetic results are presented for horizontal and vertical components of ground motion.