Discrete wave equations could be used to monitor the pile responses due to either the superstructure loads or the earthquake excitations. This paper introduces a procedure called EQWEAP, calculating the seismic ground motions or corresponding earth pressures, and its application to the wave equation analysis of pile. Alternatives of the wave equation solutions are discussed in solving soil liquefaction and lateral spreading problems. Corresponding finite difference formulations are presented and verified with 2D finite element solutions from ABAQUS analysis. Although the kinematic soil-pile interactions are ignored in the approximation, this procedure could still provide rational solutions to seismic analysis of the pile responses for routine design practice.