the present invention relates to a method for facilitating monitoring , in the course of time , of the evolution of an underground zone by compared analysis of a certain number n of seismic record sets obtained respectively after n successive 3d seismic surveys . the method comprises using a pattern recognition technique applied to all of the seismic events of the n surveys considered and analysed simultaneously , which allows to show the evolutions of the seismic events in the subsoil . application : monitoring of changes occurring in a reservoir zone of the subsoil during production for example .