Crustal structure in the eastern Alps from ambient-noise tomography

Since the onset of continental collision in the eastern Alps, several large-scale reorganizations have affected the crustal structure, such as Adriatic indentation, eastward extrusion or the Tauern window exhumation. This work aims to improve the understanding of the tectonic history of the region, by providing a new shear-velocity model of the eastern Alpine crust. It makes use of data from the AlpArray and the dense SwathD networks from which phase velocities are measured. These are inverted in a two-step approach based on a Markov-Chain Monte Carlo sampler to obtain the model structure and its uncertainties. The shallow structure is well correlated with the major faults in the area. Additional information from the anisotropy at mid to lower crustal levels is interpreted in terms of the strain direction. Eastward orientated fast axis are observed at a large depth range in the central part of the mapped region. This may indicate that the eastward extrusion affects all crustal levels down to Moho depths. The mapped features are compared to previous works from local earthquake tomography and receiver functions to provide a joint interpretation of the crustal structure.