Pic of the day #27
Pic src: Earth Structure – An introduction to structural geology and tectonics
(a) Movement of an edge dislocation, which may be likened to the movement of a caterpillar.
(b) Movement of a screw dislocation, which is analogous to tearing a sheet of paper, with the screw dislocation at the tip of the tear. After the dislocation passes through the lattice, it leaves behind a strained crystal with a perfect crystal lattice structure. The dislocation line, l, and the glide planes (shaded) are shown.