SCALES OF STRUCTURAL HETEROGENEITY WITHIN NEOTECTONIC NORMAL-FAULT ZONES IN THE AEGEAN REGION

Structural heterogeneities within neotectonic normal fault zones in the Aegean region are important controls on the geomorphic expression of their uplifted footwall blocks. Contrasting fault rocks and slip-plane phenomena (corrugations, comb fractures, slip-parallel fractures and pluck holes) are responsible for mesoscopic inhomogeneities within fault scarps. Along-strike disruptions in the continuity of fault scarps (step-over zones, step-up zones, step-down zones, footwall cross-faults and hangingwall cross-faults) are products of perturbations in slip-plane geometry or intersections with transverse faults. Large-scale variations in range-front morphology reflect contrasting patterns of deformation within fault zones. Some major fault zones, and many minor fault zones, are characterized by a migration of the active slip plane towards the hangingwall, resulting in a distributed network of high-angle faults and a range front which is stepped in profile. The presence of a localized mass of uneroded bedrock (hangingwall salients) protruding from the hangingwall of some major fault zones, results in intense deformation along a principal slip plane, and a range front which is ramp-like in profile. As a consequence of structural heterogeneities within neotectonic normal fault zones, fault scarps and range fronts in the Aegean region are subject to a temporally and spatially variable pattern of degradation.