A fault is a planar fracture of the earth’s crust that places two parts of the earth’s rock (fault blocks) in internal contact that slide relative to each other due to forces on the Earth. A fault is roughly described as a plane defined by dip-direction/dip and a slip vector defined by trend and dip. Depending on the direction of the main ones involved, the fault plane assumes a typical spatial arrangement, and the two fault blocks will move (relative displacement) with different kinematics. Movement along a fault can be characterized by slow and continuous movements (stable sliding or creeping) or by rapid movements, which generate earthquakes (coseismic phase), alternating with periods of arrest during which energy is accumulated through an elastic deformation (phase inter seismic). The internal forces of the Earth acting on the upper crust store elastic energy in the rocks surrounding the fault, deforming them. When the elastic deformation overcomes the frictional forces existing on the fault plane, the energy is released. At the same time, the two fault blocks undergo an instantaneous displacement proportional to the accumulated elastic deformation. A prevalent horizontal extension of the earth’s crust, accompanied by vertical lithostatic load, gives normal faults. Normal faults generally have plane dip of around 60°. Often, in mountainous areas such as the Apennines they separate and control slopes, raising reliefs and lowering plains. The instantaneous displacement that occurs during an earthquake on the fault plane produces permanent deformations of the crust, which are also visible on the surface. With the repetition of earthquakes on the same fault over time, these effects (called coseismic) accumulate and amplify, leaving a permanent mark in morphology. For example, the coseismic movement of a normal fault determines the formation of a step on the surface; the repetition of these events produces the formation of relief and the associated basin separated by the fault line; these continue to grow with each earthquake on the same fault. The landscape that surrounds us takes on typical connotations linked to the geology and dynamics that characterize it. Lithologies, faults, and water systems are the elements that leave the strongest footprints that we can recognize. The velocity dependence of fault frictional strength is controlled by the microphysical processes that accommodate shear deformation within the fault sliding medium. A mature fault at depths where brittle/frictional behaviour dominates consists of accumulated granular wear material or fault gauge. (Fault rock and fault mechanisms, J.Geo.Soc.London, 133,191-213, Sibson, 1977).

This study starts to obtain greater accuracy, as the latest studies and works of literature date back to the survey carried out drafting sheet 172 Caserta (1: 100.000; Servizio Geologico d’Italia, 1971). In this regard, a detailed survey of the area around Rocchetta and Croce was carried out, with particular attention to the numerous tectonic structures that continuously invert the geometric relationships between the Jurassic-Cretaceous and Miocene successions. The sampling phase of the cataclastic zone of the normal Rocchetta-Bellona fault was part of the survey work to obtain additional information through a microstructural analysis.