1. Method to determine coherent events of a seismic image, using a computer to perform the steps of: selecting: a segmentation criterion which is a function of a variable represented in the form of a seismic image such as the amplitude, contrast, gradient of a zone of the image to be qualified, at least one sliding window on said zone and its characteristics, said characteristics comprising at least one of dimensions and overlapping rate, hierarchically segmenting, for overlapping sliding window positions, said zone into n regions and for each pixel referenced at least once by a segmentation boundary: saving of the number of times for which the pixel is referenced by a segmentation boundary for each sliding window to which it belongs and calculating the ratio of said number by the maximum theoretical number of times that said pixel could be referenced, said ratio corresponding to an index ECI; attributing, for each segmentation boundary a hierarchical level based on a calculation which is a function of a determined criterion comprising a surface area of the boundary, so as to obtain an index EII; attributing to the non-referenced pixels, and an index value EI and EIC corresponding to a numeric or alphanumeric characteristic non-value; and determining coherent events of the image by thresholding the indices EII and ECI, said thresholding comprising only selecting the referenced pixels of the zone corresponding to values less than or greater than a fixed threshold.