Study on the influence of the seafloor soft soil layer on seismic ground motion

Abstract. In the complex medium system of sea area, overlying seawater and surface soft soil have a significant impact on seafloor ground motion, which brings great seismic risk to safety offshore-engineering structures. this paper, four sets typical free-field models are constructed established, comprising land model, model with soil, soil. The dynamic finite-difference method is used carry out two-dimensional response analysis free field based input forms P SV waves. By comparing results groups calculation models, effects peak acceleration spectrum studied. show that when an wave input, seabed can be amplified, while significantly reduce motion. When used, effect ignored. decreases first then increases from bottom surface, difference calculated by not obvious. layer little motion below surface.