There are many mechanisms for fault segmentation with echelon patterns. The simplest one is similar to segmentation of opening mode fractures. Faults may also branch into segments as they grow. This notion is common in seismology in which seismic signature of faults is believed to be generally simpler at depth than that at the near surface implying that earthquake faults breakdown as they approach the surface. Another is that vertical anisotropy (e.g., alternating brittle-ductile units) may cause vertically segmented faults. For example, the segmented normal fault array in sand-shale sequence presented under 'Fault Segments' can be interpreted this way.

One of the most common mechanisms for segmentation is inherited from the earlier structures whether they are opening (echelon joints), closing (echelon pressure solution seams), or mixed-mode structures. Once started from different planes of weakness, fault interaction becomes the dominant factor for determining the ultimate geometry of the faults. See 'Interaction of Faults' for details.

It should be noted that there is also a trend opposite to the breakdown or segmentation in that a newer continuous fault may link previous fault segments thereby simplifying the fault geometry as deformation across and along faults increases. This new, so-called 'through-going' fault forms by cataclastic deformation along already weakened zones of fragmented and comminuted rock. See the section 'Growth of Faults.'