9725711 Wiltschko There is a general consensus that high fluid pressure is an important controlling mechanism for the evolution of accretionary prisms and the motion of individual thrust sheets in a continental fold and thrust belt. However, the existence of such high fluid pressure in ancient thrust belts remains problematical for lack of direct evidence in ancient continental thrust belts, this project will develop a more complete hydromechnical model of a layered wedge that incorporates strength and hydraulic heterogeneity. Data on actual mechanical properties of rocks such as yield strength, strain hardening/softening behavior and hydrologic permeability will be included in a finite element analysis. Results should provide a critical wedge model that includes these important hydrologic and mechanical parameters so that the role of high fluid pressure during rock deformation can be properly assessed.