APPLICATIONS OF NON-LINEAR FINITE ELEMENT MODELING TO PROBLEMS IN STRUCTURAL GEOLOGY AND TECTONICS
Two different applications of FE modeling are described. The first is focused on the incorporation of realistic anisotropic effects into models of thrust-related folding. A flat-ramp-flat footwall is overlain by a deformable hanging wall sequence separated by a frictional interface. The influence of mechanical anisotropy is assessed via two approaches: (1) an anisotropic plasticity constitutive relationship; and (2) hanging wall layering assigned different material behaviors. These simulations can be compared to existing geometric/kinematic models or natural geologic structures (i.e., geometry and kinematics), and also provide complete mechanical histories for analysis. The second application focuses on secondary faulting and the stress/strain history during extension and subsequent inversion of a listric fault, including effects from syn-tectonic deposition and subsidence. Based on a North Sea oil/gas field example, this simulation demonstrates the advantages that FE models offer in that a cumulative stress/strain history is produced for a large scale problem involving complex geometries and multiple tectonic episodes.