Site Amplification of the Strong-motion Stations in Taiwan Derived from Their Shallow Shear-wave Velocity

Site Amplification of the Strong-motion Stations in Taiwan Derived from Their Shallow Shear-wave Velocity

In our previous study, the one-dimensional shallow shear-wave velocity (Vs) profiles of the Taiwan Strong Motion Instrumentation Program (TSMIP) stations were estimated using the Receiver Function (RF) technique. However, the accuracy of the velocity models should be evaluated for further applications. In this study, the records of the TSMIP stations are analyzed using the horizontal to vertical spectral ratio (HVSR) method to get the observed site effects. The theoretical transfer function of the Vs profile can be calculated for every station because the estimated shallow Vs profiles are from the ground surface to the deep bedrock and include the range where the seismic site effect principally occurs. The calculated transfer functions can be seen as the one-dimensional theoretical seismic site effects of the TSMIP stations and can be compared with the observed HVSRs from the seismic records. All these comparisons indicate that the shallow Vs profiles of the TSMIP stations, as obtained using the RF method, are mostly reliable and represent the real seismic site effect. The site predominant frequency and site characteristics of a station can be reproduced by the theoretical transfer function. Misestimates may come from 3D structural effects, surface waves, and attenuation effects. These Vs profiles and the combined model of the shallow part that dominates the seismic site effect will benefit ground motion predictions and numerical simulations in seismology and earthquake engineering.