The North Anatolian Fault (NAF) has a history of large quasi-periodic large earthquake clusters. This study investigates the phenomenon with a model consisting of three strong velocity-weakening (VW) asperities separated by velocity-strengthening VS barriers in a 2.5D model governed by rate-and-state friction. The results show that the after-slips at the VS barrier control the stress interaction and synchronization; hence, the barrier strength and size are the most important parameters. The static stress transfer can lead to immature ruptures that arrest within the VW asperity, adding complexity to failure times. The asperity size appears insignificant, challenging previous theories linking barrier efficiency to the asperity-barrier size ratios. Such discrepancy suggests that slip type, e.g., slip-pulse or crack-growth, influences the long-term failure time distribution. Even though the state evolution (aging and slip laws) for frictional strength within the RSF framework differ significantly in co-seismic ruptures, they resemble each other for after-slip propagation, highlighting the importance of after-slip propagation and adding robustness to our conclusions. The results from various simulation scenarios suggest that the after-slip extents and duration with the peak slip rates and rupture speeds are the indicators for the synchronization and the predictability of large earthquakes. Despite the simplicity of the governed model, the results can mimic the synchrony of large earthquakes along the NAF, which are disrupted by aseismic creep and complex fault geometries such as releasing bend (e.g., Cinarcik segment), step-overs (e.g., Niksar) and slip partitioning (Duzce-Bolu segments) acting as barriers.

Convergence between the Eurasian and the African plates in the West Anatolian-Aegean region results in a trench retreat due to slab roll-back and tearing of the subducted African lithosphere. The upper plate response of this process gave way to back-arc extension in the region. In this context, we have conducted a very rigorous AMS study on the Neogene units in SW Anatolia to unravel the style and amounts of deformation. For this purpose, from 83 sites in 11 structurally homogeneous domains, 1680 paleomagnetic samples were analyzed. Obtained results are used to determine principal strain directions to unravel overall deformation styles and amounts in the region. The results have shown that AMS is related to the tectonic deformation, which facilitated that the AMS directions correspond to cumulative principal strains. Maximum susceptibility is parallel to the major extension (k), minimum susceptibility (k) corresponds to compaction after deposition, almost always normal to the bedding plane. The intermediate axis (k) found to be parallel to a second extension direction that the region has been under the control of multi-directional extension during Neogene. Two mean anisotropy directions are identified. These are Oligocene-Middle Miocene NW-SE, and Late Miocene-Pliocene NE-SW directed extension. The mean anisotropy directions are generally parallel or perpendicular to the general strikes of the normal faults. The results have shown that the deformation in the region resembles to differentially stretched rubber sheet under the influence of SW directed extension exerted by the southwards retreating Eastern Mediterranean subduction system.