Digital sandbox modeling using distinct element method: Applications to fault tectonics

Structural deformation by faulting and folding has been analyzed by sandbox experiments that appropriately model the brittle behavior of the upper crust. This type of physical experiment using granular materials can also be done by numerical simulation (digital modeling) using the distinct element method (DEM). This chapter presents a set of two-dimensional simulation results of structural deformations using the DEM in basic tectonic settings of extension and contraction and also in the indentation tectonics as a consequence of continental collision of India. By comparing with analog experiments, the simulations reproduced fault systems similar to those of the experiments in terms of the overall deformation geometry and their development sequence. In particular, characteristic features of the Indian collision tectonics, such as fragmentation and rotation of continental blocks, were clearly identified in our DEM simulation. Because the DEM digital modeling is cheaper and faster than conventional sandbox experiments and it can incorporate discontinuity surfaces properly, the method can prove to be a powerful tool to simulate fault-related phenomena, such as structural traps in sedimentary basins. The DEM is a forward-modeling technique and can provide useful information on possible deformation pathways.