J. W. Rudnicki is interested in the inelastic behavior and failure of solids, especially geomaterials and the coupling of deformation with pore fluid diffusion. Applications include deformation of the Earth's crust, mechanics of earthquakes, hydrocarbon recovery and sequestration of carbon dioxide. More specifically, he is interested in the mechanics of earthquake faulting, the coupling of deformation and diffusion in the earth's crust, and constitutive models for rocks, especially in relation to the analyses for the development of localized deformation.