Simulating Shallow Soil Response Using Wave Propagation Numerical Modelling in the Western Plain of Taiwan

Abstract

This study used the results from 45 microtremor array measurements to construct a shallow shear wave velocity structure in the western plain of Taiwan. We constructed a complete 3D velocity model based on shallow and tomography models for our numerical simulation. There are three major subsurfaces, engineering bedrock (V S = 600 m s -1 ), Pliocene formation and Miocene formation, constituted in the shallow model. The constant velocity is given in each subsurface. We employed a 3D-FD (finite-differences) method to simulate seismic wave propagation in the western plain. The aim of this study was to perform a quantitative comparison of site amplifications and durations obtained from empirical data and numerical modelling in order to obtain the shallow substructure soil response. Modelling clearly revealed that the shallow substructure plays an important role in strong ground motion prediction using 3D simulation. The results show significant improvements in effective shaking duration and the peak ground velocity (PGV) distribution in terms of the accuracy achieved by our developed model. We recommend a high-resolution shallow substructure as an essential component in future seismic hazard analyses.

Stochastic ground motion simulation of the 2016 Meinong, Taiwan earthquake

“…The shallow velocity structure of the Chianan plain was investigated using the microtremor array analysis (Kuo et al 2016a). The soil response was simulated (Chen et al 2016) by considering the shallow structure, and the results revealed that the shallow soft layers influenced the duration of seismic wave shaking and ground motion amplification in the Tainan area. Darragh and Shakal (1991) analyzed spectral ratios for two rock and soil station pairs and estimated the site response from weak and strong ground motions.…”