ESTIMATION OF THE VARIATION IN APPARENT DISPLACEMENT ALONG NORMAL-FAULT TRACES REFRACTED BY DIFFERENTIAL COMPACTION

Initially planar fault surfaces can be refracted by differential compa ction, sudden changes in the displacement gradient taking place at the contact of different lithologies. As a result, the original displacem ent pattern, e.g. a cone-type in an idealized case, can be changed int o a zigzag-type, especially when the initial dip angle of the fault an d differential compaction are high. Compared with pre- and syn-faultin g compaction, post-faulting compaction is more likely to change the in itial displacement pattern along normal faults which were active near the sediment surface. Based upon the assumption that compaction is hom ogeneous vertical strain, the original fault geometry and displacement pattern can be estimated by means of decompaction and related geometr ic calculations.