Breaks/fractures in the Earth’s crust along which movement has occurred.

Faults with inclined fault planes have footwalls (under the fault plane) and hanging walls (above the fault plane).
The general term of "dip-slip faults" is given to faults where there is vertical movement along the fault plane.

Fault planes can become mineralized (form a channel for mineralizing fluids).

Faults are classified according to their relative motion:
Normal Fault: hanging wall has dropped relative to the footwall.
Reverse Fault: footwall has dropped relative to the hanging wall
A reverse fault is classified as a thrust fault if the fault plane has a shallow dip (<45˚).

Lateral or Strike Slip faults have almost vertical fault planes and show offsets in a horizontal plane.
Right-lateral strike-slip faults – the block on the opposite side of the fault has moved to the right and vice versa for left-lateral faults.