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In the Aegean area, distinct fault patterns with their associated stress regimes are evidenced along a curved convergent plate boundary. In this article, we analyze and review late collisional and extensional structures in five structural regions along the External Hellenides orogenic belt in order to define, primarily, the evolution of onshore basins and, secondarily, the evolution of off-shore basins and the role of the inherited structures within the present geotectonic framework. We also evaluate how these structures act on seismicity as well as present-day motion and magmatism in the Aegean area.Northwestern Greece, which corresponds to our Region I, represents an area of active continental collision in which a previously overthickened crust collapsed mainly parallel to the structural grain of the orogen. At present, the most active structures in this region are the northwest-trending thrusts and the northeast-trending normal faults. Strong coupling and the transmission of horizontal forces from the collision front appear to explain the deformation within this region.Central Greece (Region II) displays a mixed type of contractional-extensional deformation. Mesozoic inherited transverse structures are reactivated as WNWtrending faults and appear to accommodate most of the active north-south-trending present-day extension. Deformation in this area appears to be controlled both by rollback of the subducting slab and by the lateral extrusion of the Anatolia plate.The areas that spread along the more curved parts of the Hellenic arc (Regions III and V) well emphasize the control exerted by pre-existing northeast-trending structures as well as their long-lived activity during the evolution of the arc. Present deformation within these regions possibly reflects the oblique convergence process, which is occurring in both areas in different degrees.Finally, analysis of deformation patterns in the central part of the Hellenic arc and the Aegean Sea (Region IV) suggests that almost all pre-existing structures have remained active until the present and accommodate extensional deformation and rapid motion through a nonorthogonal fault system that crosscuts a thin and thermally weakened continental crust. Deformation north of our Region IV is accommodated 97 *

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Combined shear-sense criteria, finite-strain data and vorticity analyses were used to study the deformation path in a curved crustal-scale shear zone (Phyllite-Quartzite Series) of the southwestern Hellenides. The results are combined with data on the structural evolution of a cover nappe (Pindos thrust belt) to provide new insights into the orogenic evolution of this region.Ductile deformation within the Phyllite-Quartzite Series was associated with a top-to-the-westsouthwest shearing and was partitioned into two structural domains: a root zone and a frontal domain. The root zone is characterized by vertical coaxial stretching, high strain and upward movement of the material, while the frontal domain comprises simple-shear deformation at the base and pure shear at the top. This pattern suggests superposition of pure shear on simple-shear deformation, and implies tectonic extrusion of the material from the root zone.The initiation of brittle deformation in the Pindos thrust belt was associated with westward translation above the sub-horizontal Pindos Thrust. Later, as the mountain range elevated, normal faulting at high altitudes and migration of thrusting to the west occurred, while east-directed folding and thrusting in the belt started to the east.According to the proposed model, crustal thickening was taking place throughout the Oligocene and early Miocene, including the subduction of the Apulian beneath the Pelagonian microcontinent and the intracontinental subduction of the Phyllite-Quartzite Series. During the lower Miocene, vertical buoyancy forces led to the successive steepening of the shear zone and the simultaneous duplexing of its basement, facilitating tectonic extrusion of the material from its root zone. Finally, an indentation process caused vertical expulsion of the orogenic wedge and gravity collapse in the brittle crust.

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