Study on 2D in-plane HVSR simulation and application with transverse inhomogeneous body scattering

In order to analyze the significant influence of lateral inhomogeneity of site on horizontal-to-vertical spectral ratio (HVSR) curves, the diffuse field approach proposed by Sánchez-Sesma et alwas adopted to simulate the HVSR curves of 2-D sediment topography by calculating the imaginary part of Green’s functions of total wave field. The imaginary part of Green’s functions was solved by the dynamic stiffness matrix and in-plane inclined Green’s functions based on the indirect boundary element method (IBEM). The HVSR curves of 2-D sediment topographies and corresponding 1-D layered half-space were compared, the influences of sediment topography shapes and the relative position of calculation points on the HVSR curve were discussed in detail. The results show that the effect of impedance ratio between inside and outside materials of sediment topography on HVSR is the most significant; With the increase of the impedance ratio and the slopes of the interface on the sediment side, the frequencies of the first peak of HVSR curves increase significantly, which can be up to 3.3 times of the corresponding layered half-space results, simultaneously, platform emerges on HVSR curves; Amplitudes of HVSR curves in high frequency band increase with the decrease of distances from the calculation points to the sediment boundary. According to the results obtained in this study, the HVSR method can be used to preliminarily determine the place where local sediment topography exists. From this aspect, the cost of regional geophysical investigation can be reduced visibly via HVSR method.