A computer executable algorithm adapted to propagate a boundary surface of a seed that is placed within a region of interest of a visual representation of a 3D seismic data so as to follow a natural contour of said region of interest, wherein said algorithm is executable to: (i) generate at least one attribute volume comprising at least on attribute derivable from said 3D seismic data set; (ii) generate at least one characteristic parameter for a plurality of candidate events of said 3D seismic data within a predefined gate region located forward of said propagating boundary surface; (iii) generate and assign a probability characteristic for said plurality of candidate events based on said at least one attribute volume and said at least one characteristic parameter; and propagate said boundary surface towards and incorporating any one of said plurality of candidate events that fulfils an acceptance criteria of said probability characteristic so as to generate a surface along the natural contour of said region of interest.