Recursive stiffness matrix method for wave propagation in stratified media

A stable recursive stiffness matrix method is described for wave propagation in a layered elastic medium. The 4 X 4 global stiffness matrix for a stratified medium is recursively calculated from the layer stiffness matrices. The layer stiffness matrix has only six different elements, which are given in closed form. For general buried sources, a simple formulation has been developed to calculate the response for arbitrary positions of the receivers. Based on this method, characteristic equations for surface and guided modes in stratified media have also been obtained. The algorithm is unconditionally stable and retains the simplicity and flexibility of the transfer matrix method.