We present a simplified geophysical model to evaluate the deformation field of the local lithosphere during a marked swell of the River Plate. The influence of this phenomenon on the displacement field is analyzed. The differential equations of elastic equilibrium were solved by means of a three dimensional finite element method with appropiate boundary conditions. The results obtained indicate that very high precision measurements would be neccesary to quantify these effects. This, in turn, would allow us to improve the estimation of the elastic parameters of the area.Facultad de Ciencias Astronómicas y Geofísicas