In the second funding period of this project, we plan to extend our numerical simulations to single faults in viscoelastic materials and, in parallel, concentrate on the investigation of multiscale fault networks. In particular, we will develop analogue experiments that involve networks of nonplanar, dipping faults with frictional heterogeneities in a layered crust under spatiotemporally variable loading conditions such as relaxation or triggering. On the mathematical side, we will concentrate on numerical methods for viscoelastic multiscale fault networks in 2D and 3D with viscous foundation. As in the first funding period, numerical analysis will be strongly connected to analytical foundations, addressing, e.g., homogenisation and closure of multiscale interface problems. As a joint effort of analysis, simulation, experiments, and data-driven modelling (Mercator Fellow) our goal is to investigate the multiscale structure of fault networks in order to provide a phyical understanding, e.g., of recently detected slow slip events and silent earthquakes apparently filling the gap in scales between short- and longterm geodynamic deformation processes.