3-D Mantle Flow and Structure of the Mediterranean From Combined P-Wave and Splitting Intensity Anisotropic Tomography

Abstract

We present a novel three-dimensional anisotropic seismic tomography model of the Mediterranean region, achieved through the simultaneous inversion of P-wave travel-times and SKS splitting intensity. This dual approach has allowed us to obtain a comprehensive tomographic model that not only delineates the primary structural features of the area but also sheds light on its tectonic evolution. Our findings reveal that the isotropic component of the model is dominated by fast anomalies associated with retreating, stagnant, and detached slab segments including the Alboran, Apennine, and Alpine slabs in the central and western Mediterranean, and the Dinaric, Carpathian, and Hellenic slabs in the east. Slower mantle structures are associated with slab windows and back-arc basin formation, such as those observed in the Tyrrhenian, Apennine and Hellenic regions. The recovered anisotropic patterns provide crucial insights into the tectonic history of the Mediterranean, highlighting periods of collision and tectonic relaxation. Notably, we observe a range of plunge angles, with both near-horizontal and steeply dipping anisotropic fabrics present in different regions, reflecting the influence of horizontal and vertical asthenospheric flow. By interpreting the high-velocity zones as subducting lithosphere, we construct a detailed 3-D model of the main slabs and analyzed the surrounding P-wave anisotropic patterns. This work represents the first comprehensive anisotropic tomography study of the entire Mediterranean region.