Modeling complex, nonlinear geological processes

We review selected geological processes to which numerical modeling has been applied, with the aim of describing some of the general approaches and applications of the modeling. All of these examples involve multiphase fluid flow, in some cases coupled with heat transport and phase changes. First, we describe modeling approaches to a human-made geological system-a potential underground radioactive waste repository. Next, we describe recent advances in modeling two-phase flow through random heterogeneous porous media. We review recent modeling studies of fluid processes in magmatic systems, especially focusing on melting and crystallization induced by magma chambers. Finally, several research directions are suggested, including improving our understanding of the linkage between small-scale and field-scale processes, coupling across regimes (e.g., surface water and ground water), and further developments in the modeling of stochastic geological processes.