Crust-Uppermost Mantle Shear-wave Velocity Structure and Buoyancy Flow Model beneath the Tyrrhenian Basin and Surrounding Margins

The Tyrrhenian basin serves as a natural laboratory for back-arc basin studies in the Mediterranean region. Yet, little is known about the crust-uppermost mantle structure beneath the basin and surrounding margins. Here, we present a new 3D shear-wave velocity model and Moho topography map for the Tyrrhenian basin and its margins using ambient noise cross-correlations. We apply a self-parameterized Bayesian inversion of Rayleigh-wave group and phase velocity dispersions to estimate the lateral variation of shear velocity and its uncertainty as a function of depth down to 100 km. We also derived a contemporary 3D density model of the lithosphere beneath the Tyrrhenian region by combining seismic velocity, surface heat flow, gravity and topography. Further, we investigated the contribution of buoyancy forces to the regional dynamics by modelling the lithospheric flow field below the Tyrrhenian basin and margins using as input the 3D lithospheric density structure beneath the study area. In general, our models support present-day geodynamics with a predominant Africa-Eurasia convergence and provide new insights into the geodynamics and magmatism in the Tyrrhenian basin and surrounding margins.