Tectonic forces cause rock deformation causing change in orientation, location, and shape. Stress is measurable force per unit area at a point. Strain is change in size (volume) and/or shape. Elastic: deformed material recovers original shape after stress is reduced/removed: elastic limit: the limit to which rock can bend before damage is permanent. Ductile (plastic): bends under stress and remains as such: permanent damage due to folding or bending of rock layers, folds: permanent wavelike deformations in layered rocks. Brittle: rock breaks under stresses: result in faults or joints; fault: fracture in bedrock along which rocks on one side move/displace relative to the other side. Joint (or joint sets): fracture/crack in bed rock w/o displacement: compressive forces cause: reverse faulting, tensional forces cause: faulting, shear forces cause: strike-slip faulting. Rocks response influenced by: stress type, rock type, temperature, pressure, fluids, length and magnitude of stress applied. Uses standardized symbols and patterns to represent rock types and geologic structures.