Class Note 10 Geologic Structures Stress and Strain Stress is the applied force. Strain is the resultant deformation. Stress can be compressional, tensional, shear, or isostatic. Compressional stress pushes matter together.
Tensional stress pulls matter apart.
Shear stress is rotational. Isostatic stress is even pressure as with burial. Strain can be elastic or plastic. If a material undergoes continuous plastic deformation, it is said to be ductile . If it fractures, it is said to be brittle .