The present invention relates to a method to process a three dimensional seismic image. The method comprises, for a center point and for a plane comprising said center point, determining a first maximal correlation between a first vector of the seismic values associated with at least a point of the seismic image having a distance to the center point below the predetermined distance and on a first line, and a second vector of the seismic values associated with points on a second line parallel to the first line, determining a second maximal correlation between the first vector, and a third vector of the seismic values associated with points on a third line parallel to the first line, and determining a difference value based on at least a difference between the first maximal correlation and the second maximal correlation.