Propagator matrix for continuously layered porous seabeds

Abstract

The analytical expression of the propagator matrix for elastic waves in a continuously layered porous plasto-elastic medium is obtained. The Biot theory incorporated with the linearized expressions of soil anelasticity is used to model sediments. Numerical calculations are made for the P-SV motion of seabeds excited by shear and compressional waves. It is found that the sediment layers have very little effect on the seismic reflection at the sediment-rock interface. However, the excitation of the sediment layer is sensitive to the profile of sediment properties, frequency, and wave amplitude. The dynamic behavior of coarse sand and porous rocks excited by acoustic waves and earthquakes should be modeled by the Biot porous-solid model in which the fast compressional waves, the slow compressional waves, and the shear waves are included. However, excitations of most marine sediment beds by earthquakes may be modeled by the Biot solid model in which the slow compressional waves are omitted in the Biot porous-solid model.