Assessing small-scale Surface Deformation zones in Europe

Dense GNSS station networks and derived highly accurate 3D velocities offer the potential to image small-scale surface deformation fields. The robustness and sensitivity of the applied algorithm are crucial for the reliable detection of local and potentially small horizontal or vertical deformation zones. Based on a multivariate median estimation of strain rate and plate rotation, the imaging approach R3DI (Robust 3D Imaging) enables robust estimation, with the achieved spatial resolution dependent solely on the density of the station network and the local strain rate.In this contribution we will discuss the impact of significance tests applied to the second invariant of the strain rate tensor and to the dilatational rate. The achievable spatial resolutions will be tested using synthetic deformation patterns (checkerboard tests) and real GNSS velocity fields in Europe. In a second step, the optimal grid spacing as trade-off between surface deformation recovery, density of the GNSS station network, and computational costs will be investigated.