Structural and time constraints for dextral shear along the seismogenic Mattinata Fault (Gargano, southern Italy)

We present here some new evidence for the occurrence of both right-lateral and left-lateral motion along the Mattinata Fault System (MAFS), a seismogenic structure in the southern sector of the Gargano promontory (Apulia, southern Italy). Right-lateral motion along the MAFS is recorded by geomorphic and structural features which suggest that dextral shear characterizes the most recent kinematic behaviour of the structure. Earlier left-lateral motion along the MAFS has been inferred mainly from the occurrence of localized pervasive pressure solution surfaces that are consistent with sinistral shear and by the presence of the Pantano di Sant’Egidio pull-apart, located in the left-stepping overlap zone between two major fault segments of the MAFS. Observed displacement values and computed slip-rates also allowed us to estimate, for the late dextral motion along the MAFS, a chronological interval of activity which is not less than 200 ka.