Any rock deformation that is not instantly recoverable without permanent loss of cohesion. Also known as flowage; rock flowage. Instantaneous movement of material particles making up a deforming volume of rock. If flow is homogeneous, the pattern of particle displacements can be described by a simple velocity field, or flow pattern. A velocity field describes the motion of a population of material particles at a given instant in time. A sequence of velocity fields, describing the accumulation of finite displacements of material particles with time, is a deformation path or progressive deformation history. Here we must clearly distinguish between the notions of ongoing progressive deformation and the end product of the progressive deformation (finite deformation, finite strain)
Related terms: