The mechanisms of fracture and flow in rocks and ceramics are remarkably similar. As a result, studies of the mechanical properties of Earth materials that ultimately govern the behavior of the lithosphere have benefitted from mineral and rock physics approaches resembling those taken in the study of structural ceramics. Laboratory studies of fracture propagation and frictional sliding in rocks have led to advances in our understanding of earthquake mechanics [e.g., Tullis, 1986; Segall, 1991] much as experimental studies of engineering materials have aided in the prediction of failure and wear of critical structural components.
Studies of mineral plasticity and ductile flow of rocks [e.g., Evans and Dresen, 1991] have revealed that nonlinear time-dependent rheologies, as first described for metals and ceramics, govern mechanical response at high temperatures and pressures with pronounced effects on the scaling and evolution of continental collisions [England et al, 1985; Houseman and England, 1993]. Studies of the mechanical and transport properties of partial melts and glass ceramics [Cooper, 1990] are now providing insights into the delivery of melts to active ridge axes [e.g., Phipps Morgan, 1991]. Investigations of phase transformations in silicate and oxide systems have revealed mechanisms that are both thermally driven and stress-induced, and experiments designed to examine phase transformations under nonhydrostatic stresses have provided insight into the source mechanisms of deep-focus earthquakes [Kirby et al., 1991; Green et al., 1992].