GEOMETRY, KINEMATICS AND RATES OF DEFORMATION IN A NORMAL-FAULT SEGMENT BOUNDARY, CENTRAL GREECE

The geometry, kinematics and rates of deformation within a fault segme nt boundary between the ends of two major active normal fault segments have been investigated through examination of a faulted 126 ka marine terrace. Slip-vector azimuths defined by striations on the faults ind icate N-S extension on c. E-W faults, sub-parallel to those from earth quake focal mechanisms, together with significant and contemporaneous E-W extension on c. N-S faults. Summed rates of E-W extension along a c. 550 m transect (0.17 mm/yr) are comparable with those for N-S exten sion (0.20 mm/yr) along a c. 350 m transect. Our observations show tha t distributed non-plane strain extension occurs in fault segment bound aries and this should be noted when studying fault-tip fracture toughn ess and regional deformation rates.