In geology, diastrophism refers to movements of the earth's solid crust (i.e. plate tectonics) that result in deformation or displacement. The origin of these processes probably lies in seafloor spreading.

The major categories of deformation resulting from diastrophism are

  • folds, in which the rock bends but does not break,
  • faults, breaks in rock accompanied by displacement, and
  • joints, fractures in rock without displacement.