The tectonophysics group is internationally recognized for effectively combining experimental, theoretical, and field studies to determine physical processes operative in the Earth's crust and mantle. Geophysicists Fischer, Forsyth, and Parmentier study the processes that govern plate tectonics, including the pattern of flow in the mantle, the generation of earthquakes, and the formation of new sea floor at mid-ocean ridges. Geophysicist Hermance uses environmental field studies to address hydrology questions including groundwater flow and contaminant migration (see also Environmental Science). Structural geologists J. Tullis and T. Tullis combine experimental and theoretical studies of the processes and mechanics of ductile and brittle rock deformation to give insight into applications of flow in the Earth and earthquake mechanics.