A setback is often a almost vertical Faille along which a rock compartment slides horizontally compared to the opposite compartment. This relative movement adapts a horizontal lengthening as well as the horizontal shortening which would be perpendicular to this lengthening.

The setbacks (called transforming faults when they belong to a edge of plate) thus meet in all the types of geodynamic contexts.

According to the direction of relative sliding motion, one defines two types of setbacks:

• dextral Setback when the observer facing the fault sees the other compartment slipping towards its line
• sinistral Décrochement when the observer facing the fault sees the other compartment slipping towards its left