Two mechanisms for the wave-induced pore pressures in a porous seabed, i.e. oscillatory and residual excess pore pressures, have been observed in laboratory experiments and field measurements. Most previous investigations have focused on one of the mechanisms individually. In this paper, an analytical solution for the wave-induced residual pore pressure, which is not available yet, is derived, and compared with the existing experimental data. With the new solution, a parametric analysis is performed to clarify the applicable ranges of two mechanisms. Then, a simplified approximation for the prediction of wave-induced liquefaction potential is proposed for engineering practice. Two mechanisms for the wave-induced pore pressures in a porous seabed, ie oscillatory and residual excess pore pressures, have been observed in laboratory experiments and field measurements. Mostly investigations have one focused on one of the mechanisms individually. In this paper, an analytical With the new solution, a parametric analysis is performed to clarify the applicable ranges of two mechanisms. Then, a simplified pattern of the wave-induced residual pore pressure, is derived, and compared with the existing experimental data. approximation for the prediction of wave-induced liquefaction potential is proposed for engineering practice.