The nonlinearity parameter of saturated marine sediments

The sources that may account for the acoustic nonlinearity of marine sediments are discussed based on the theory for wave propagation in porous media. It is concluded that the nonlinearity parameter B/A can be expressed as the weighted sum of contributions from the nonlinear stress– strain relations of the pore fluid, the mineral grains, and the skeleton frame. Calculations of B/A for sands show the nonlinearity of the fluid to be most important with a dependence on porosity in good agreement with earlier experimental results. Some consideration is given to distortion of the finite amplitude waves and the effect of this on acoustic propagation.