In dip-slip faults, how do the sides of the fault usually move?

In dip-slip faults, the movement of the sides of the fault occurs primarily in a vertical direction, either up or down along the plane of the fault. This type of faulting is characterized by the displacement of rock masses in response to tectonic forces that cause stress in the Earth's crust. In a dip-slip fault, one block of rock, known as the hanging wall, moves relative to the other block, known as the footwall, either rising (in a reverse fault) or falling (in a normal fault). This vertical movement is a key feature that distinguishes dip-slip faults from other types of faults, such as strike-slip faults, where movement occurs horizontally.

The terms associated with dip-slip faults highlight the direction of movement: in normal faults, the hanging wall moves down relative to the footwall, indicating extensional forces, while in reverse faults, the hanging wall moves up, which is indicative of compressional forces. Understanding this vertical movement is essential for interpreting geological structures and the processes that shape the Earth's crust.