Displacement data from a normal fault system shown above. Note the large number of smaller faults in the region of linkage. The displacement on these faults when summed results in a pattern for the total fault system that is roughly representative of the displacement pattern of each of the smaller faults. This result is consistent with the faults within a fault system roughly being self-similar. There is however, some flattening of the total or summed profile with respect to the smaller faults that we suggest results from faults growing into a mechanically weak subsurface of volcanoclastic sediments. This can be thought of as analogous to large crustal-scale faults that extend to a weak ductile substrate. (Figure from Dawers and Anders, 1995).