GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 1.1 GNGTS 2024 very limited sector (in correspondence of Akarnania and Peloponnesus) the results indicate the contact between ductle rocks overlying britle ones (yellow in Figure 1c). Comparing the rheological results with the geometry characteristcs of the interface, it is possible observe some peculiarity. For example, the transiton from the britle/britle to the britle/ductle behaviour occurs at the depth range between 20 and 25 km (Figure 1a), in a narrow sector where the slope progressively varies from less than 15°, characterizing the upper- and frontal-most porton of the slab, to more than 18°, therefore in correspondence of a dip-angle change along the interface. On the other hand, the deepest sector characterized by britle rocks overlying the interface occur at 90-100 km in correspondence of a slope increase from less than 35° to more than 40°. As a very preliminary conclusion of the rheological model, britle and hence potentally seismogenic actvity in correspondence of the Wadat-Beniof zone could occur only down to a depth of ca. 100 km as far as at greater depths the 1 km-thick modelled rock volume embedding the interpolates shear zone is entrely characterized by a ductle behaviour. Accordingly, though rarely recorded deeper seismicity should likely occur due to internal deformaton of the subductng slab and not on the interface. This is in accordance with Halpaap et al. (2018); these authors, where the Wadat-Beniof zone was well-imaged, identfed earthquake clusters standing out the intraslab seismicity between 40 km and 60 km depth. Also, in Bocchini et al. (2018) the interplate seismicity is imaged at depth shallower than 100 km, while in Meier et al. (2008) the relocated interplate seismicity, ploted on reconstructed profle across the Aegean, generally don’t exceed 60 km depth, only few events are located between 80 km and 100 km. Figure 5: a) modelled Hellenic Subducton Zone (modifed from Maggini et al., 2023 and references therein) with isobaths; b) slope distributon of the modelled Hellenic Slab; c) rheological behaviour in correspondence of the HSZ.