Abstract - The 2D Distinct Element Method (DEM), in which rock is represented as an assemblage of cylindrical particles that can be cemented together, is used for modeling the growth of normal faults in layered sequences. The outcrop-scale models are comprised of strong and weak layers, modeled as bonded and non-bonded particles, respectively, which are deformed at various confining pressures using a pre-defined fault at the base of the periodically layered sequence. The models successfully reproduce a wide range of fault geometries seen in outcrop, such as lithologically controlled fault dip variations, fault bifurcation and segmen-tation, and also illustrate the progressive removal of asperities and the linkage of fault segments, which leads to the formation of fault bound lenses. A sensitivity study reveals that fault zone complexity decreases with decreasing strength of the cohesive beds and increasing confining pressure. A suite of models comprised of sequences with different proportions of strong and weak beds suggests that the overall fault zone dip increases with decreasing fraction of weak material in the sequence.
In: Mechanics of Natural Solids (edited by: Kolymbas, D. & Viggiani, G.), Springer, Heidelberg, 127-146, 2009.