Tracing Slabs and Mantle Flow in the Mediterranean with 3D Anisotropic Tomography

We present the first comprehensive three-dimensional anisotropic tomographic model of the entire Mediterranean mantle (ani-MR25, Rappisi et al., 2025), obtained through the simultaneous inversion of teleseismic and regional P-wave travel-time combined with SKS splitting intensity measurements. This dual input dataset approach allows us to resolve both isotropic velocity structures and the directional properties of mantle anisotropy, providing a detailed view of lithospheric slabs and surrounding asthenospheric flow. Our results identify fast anomalies associated with retreating, stagnant, and detached slab segments,—including the Alboran, Apennine, Alpine, Dinaric, Carpathian, and Hellenic systems—and slower regions associated with slab windows and back-arc basins, such as in the Tyrrhenian and Hellenic areas. The recovered anisotropic patterns provide crucial markers of the region's tectonic history. We observe a wide range of P-wave fast axis plunge angles, with steeply dipping fabrics correlating with slab tearing, detachment zones, and volcanic provinces. Trench-parallel anisotropy beneath slabs and trench-perpendicular orientations in back-arc regions reflect the imprint of trench retreat and subduction-driven corner flow.

By integrating isotropic and anisotropic observations, we construct a detailed 3-D model of Mediterranean slab geometries and surrounding mantle flow, offering new insights into the tectonic evolution and geodynamic processes of this complex region.

 

Rappisi, F., Lo Bue, R., Vanderbeek, B. P., Confal, J. M., Erman, C., Baccheschi, P., ... & Faccenda, M. (2025). 3‐D mantle flow and structure of the Mediterranean from combined P‐wave and splitting intensity anisotropic tomography. Journal of Geophysical Research: Solid Earth, 130(6), e2024JB030883.