Mantle flow and deformation of the eastern Adria subduction: New insights from AdriaArray seismic anisotropy

• The E Adriatic margin is illuminated for the first time with AdriaArray SKS waves. • Coastal stations show EW strike-normal sub-slab flow consistent with GPS motion. • Anisotropy changes abruptly to NW-SE (strike-parallel) across the orogenic belt. • Strong EW flow beneath a slab window at 45°N feeds the Pannonian asthenosphere. • Another slab tear at 42°N allows toroidal flow to feed mantle wedge circulation. The Adriatic slab beneath the Dinarides-Albanides-Hellenides represents a uniquely segmented and dynamically complex subduction system, where slab tears and edges significantly influence mantle flow patterns. Benefiting from unprecedented dense seismic data from the 2022–2025 AdriaArray deployment, we reveal sharp lateral variations in SKS anisotropy that directly image the mantle’s deformation response to slab fragmentation and subduction processes. Our SKS splitting analysis uncovers a striking spatial dichotomy: near-coastal stations record weak, slab strike-perpendicular anisotropy consistent with focused sub-slab mantle inflow, while inland stations above the subducted plate display robust, slab strike-parallel anisotropy reflecting organized mantle wedge deformation. Interpreted in the context of seismic tomography, our results provide evidence of two distinct slab tears at ∼45°N and ∼42°N. Here, toroidal mantle flow facilitates mantle wedge replenishment, reshaping mantle convection around the subduction system. Moreover, the slab’s north-south geometry varies significantly, influencing observed anisotropy patterns: the northern, thinner slab segment beneath the Dinarides is predominantly characterized by strike-parallel flow, likely occurring in the mantle wedge. The stations above the thicker, deeper southern segment beneath the Albanides-Hellenides exhibit more complex, multi-layered mantle flow, possibly integrating sub-slab, wedge, and slab-internal deformation components. These observations provide unprecedented direct evidence for how tear-induced mantle circulation and segmented subduction modulate mantle dynamics beneath a complex subduction zone.