Slab Rollback Orogeny Model: A Test of Concept

Abstract

Buoyancy forces associated with subducting lithosphere control the dynamics of convergent margins. In the postcollisional stage these forces are significantly reduced, yet mountain building and seismicity are ongoing, albeit at lower rates. We leverage advances of a newly developed seismo‐thermo‐mechanical modeling approach to simulate tectonic and seismicity processes in a self‐driven subduction and continental collision setting. We demonstrate that the rearrangement of forces due to slab breakoff, in the postcollisional stage, causes bending and rollback of the residual slab, suction forces, and mantle traction at the base of the upper plate, while stress coupling transfers to the shallow crust. Our results provide an explanation for the postcollisional evolution of the Central Alps, where the so‐called Slab Rollback Orogeny model explains the slow yet persistent upper plate advance, the height of the mountain range, and a seismicity pattern consistent with the different tectonic regimes throughout the orogen. © 2020 American Geophysical Union.