Block Kinematics, Interseismic Coupling and Fault Slip Rates in the Aegean Region From GPS and Earthquake Slip Vector Data: 2. Hellenic Subduction System

Abstract The Hellenic subduction system is the primary locus of Nubia‐Eurasia convergence, yet the distribution of strain accumulation along it is still debated. Here, we invert 832 geodetic velocities and 146 earthquake slip vectors to assess the spatial variability of interseismic locking and provide new constraints on the rate of slip deficit accumulation. We find that the subduction interface beneath southwestern Peloponnese and across the area from offshore south Peloponnese to offshore southwest of western Crete hosts three patches of low to moderate locking (0%–40%) at 10–50 km depth whose slip rate deficits account for ∼15–30% of the total plate convergence. The offshore weakly locked patches show a good spatial correlation with large interplate earthquakes, while the patch beneath southwestern Peloponnese overlaps with a past transient slow‐slip event, suggesting that similarly locked areas along the interface can exhibit different slip behavior. Our analysis further reveals that the Hellenic Trough fault displays a low‐coupled area that spatially correlates with the coseismic slip of the 365AD Crete earthquake and also identifies a confined region offshore of Gavdos island exhibiting higher degrees of locking. Finally, our modeling indicates that the eastern Hellenic subduction system is completely uncoupled, highlighting a fundamental difference with the heterogeneous locking of the western part. This work demonstrates that although most of the Nubia/Eurasia convergence is accommodated aseismically, localized patches prone to accumulating elastic strain do exist and it provides, for the first time, evidence for a connection between interseismic locking and large subduction‐related earthquakes along the Hellenic subduction system.