Spatially variable seismic underground motions in layered porous seabed medium induced plane wave

In ocean engineering anti-seismic filed, the marine environment is usually regarded as the coupling field of seawater-layered porous seabed-elastic bedrock. This paper presents a theoretical method to study the spatially variable seismic underground motions in stratified seabed system. Based on the potential flow theory, Biot's porous model and random vibration theory, the transfer function and coherence function model of the underground seismic motions in the marine coupling field are derived. On the basis of the above theoretical derivation, the program of the spatial variability seismic underground motions of the coupling field is simulated and developed, and its accuracy and effectiveness are verified. Moreover, the effects of soil stiffness and overlying seawater level on the seismic response are also analyzed. Numerical results show that spatially variable seismic underground motions are significantly different from those on the ocean bottom. The simulation of spatially variable seismic underground motions for layered seabed field is significant for both theoretical study and ocean engineering application.