The stability of slopes is an important part of geotechnical engineering as some of the greatest damage to property and loss of life has occurred through landslips. The simplest way to incorporate seismic effects into a slope stability analysis is to add an extra force vertically or horizontally to a slice to simulate the force due to ground acceleration. In total stress analysis of slopes that are submerged, the water can be treated as a force acting on the face of the slope and the water not considered as a separate material. The stress field is interpolated from values at the nodes of triangular elements using linear interpolation. The grid of points and the water pressure at each point can then be used with a slip circle analysis by using interpolation between the grid point values. The velocity field is then represented at the nodes of a triangular mesh and the velocities are optimised to give the lowest power dissipation.