The model contains the 3D structure of Vp and Vs in the crust and the mantle under the European Alps, as published in Kästle et al. (2025). It is the result of a direct inversion of surface-wave data, from ambient noise and earthquake records, and of teleseismic P and S wave data. A Bayesian tomography approach is used where we implement a reversible jump Markov chain Monte Carlo method to constrain the free parameters. This gives not only the mean Vp and Vs values, but also their uncertainties, as well as a distribution (histograms) of the sampled velocity parameters at each point of the model.

The Priority Programme "Mountain Building Processes in Four Dimensions (4D-MB SPP), funded by the German Research Foundation (DFG) for six years (beginning in 2017).

The 4D-MB SPP forms an integral part of the international AlpArray mission to image the structure of the Alps from their surface down to several hundred kilometers depth in the mantle. It tests the hypothesis that re-organizations of Earth’s mantle during the collision of tectonic plates have both immediate and long-lasting effects on crustal motion, fault kinematics, earthquake distribution and surface evolution. It challenges conventional wisdom by recognizing that linked processes between Earth’s surface and mantle beneath mountain belts can only be explained by integrating 3D imaging of the entire crust-mantle system with geologic observations and modeling to enable us to look both backwards and forwards in time, the 4th dimension. This requires a multi- and interdisciplinary approach that integrates geophysics, tectonics, petrology, geochronology, basin- and surface studies.