Characteristics of Seismic Response Based on the Ambient Noise Test and Numerical Simulation of Large Landslide Deposits

During strong earthquakes, large landslide deposits may be reactivated and contribute to erosion. To obtain a better understanding of the seismic site responses of large landslide deposits, field investigations were carried out on the Xingwenping landslide deposits, and ambient noise recordings were analysed by using horizontal-to-vertical spectral ratio methods to obtain site response characteristics, including resonance frequency, spectral ratio amplitude, and directional resonance. Furthermore, to determine the influence of material comparison and topography on site response, the parameters of the shear wave velocity profile were used to establish a three-dimensional numerical model. The results show that the numerical model and ambient noise have good consistency in resonance frequency and directional resonance, but the spectral ratio amplitude of the numerical model is much larger than that of ambient noise. At the same time, our results also prove that the multilayer accumulation of large landslides combined with topography plays a leading role in the dynamic response of the site. This study provides a new method for dynamic response analysis of large landslide deposits.