Deformation is the change in size or shape of a body due to the application of stress. There are two main types of deformation:
Ductile deformation occurs where a body is deformed permanently without any fracturing such as seen when folds are formed.
Brittle deformation occurs when a body changes size and shape in the presence of stress and it fractures because it is no more elastic but plastic. They produce faults and other fractures seen in rocks.
