DISPLACEMENT VARIATION ALONG THRUST FAULTS - IMPLICATIONS FOR THE DEVELOPMENT OF LARGE FAULTS

Displacement analyses along thrust faults of different maturity (or size) reveal maxima and minima, often associated with minor folding of the adjacent beds, between the tip points. The results show that these faults are segmented and that they formed through the linkage of smaller (previously independent) faults and (or) by propagation of a single fault affected by the existence of barriers. Points of potential linkage (marked by displacement minima) are fault bends or distinct fault breaks. Fault nucleation (marked by displacement maxima) occurs within the planar segments of a fault. In general, displacement variation appears to be a reflection of the symmetry of the thrust fault system such that a flat-ramp geometry ending in a steep tip will show an asymmetrical displacement function skewed toward the surface, with a nucleation point above the basal decollement.