Present-Day Upper-Mantle Architecture of the Alps: Insights From Data-Driven Dynamic Modeling

The dynamics of the Alps and surrounding regions is still not completely understood, partly because of a non-unique interpretation of its upper-mantle architecture. In particular, it is unclear if interpreted slabs are consistent with the observed surface deformation and topography. We derive three end-member scenarios of lithospheric thickness and slab geometries by clustering available shear-wave tomography models into a statistical ensemble. We use these scenarios as input for geodynamic simulations and compare modeled topography, surface velocities and mantle flow to observations. We found that a slab detached beneath the Alps, but attached beneath the Northern Apennines captures first-order patterns in topography and vertical surface velocities and can provide a causative explanation for the observed seismicity.