UAV-PPK photogrammetry, GIS, and soil analysis to estimate long-term slip rates on active faults in a seismic gap of northern Calabria (southern Italy)

The study of faults in seismic gap areas is essential for assessing the potential for future 18 seismic activity and developing strategies to mitigate its impact. In this research, we employed a 19 combination of geomorphological analysis, aerophotogrammetry, high-resolution topography, and 20 soil analysis to estimate the age of tectonically exposed fault surfaces in a seismic gap area. Our 21 focus was on the Piano delle Rose Fault in the northern Calabria region, (southern Italy), which is a 22 significant regional tectonic structure associated with seismic hazards. 23 We conducted a field survey to carry out structural and pedological observations and collect 24 soil samples from the fault surface. These samples were analyzed to estimate the fault’s age based 25 on their features and degree of pedogenic development. Additionally, we used high-resolution to-26 pography and aerophotogrammetry to create a detailed 3D model of the fault surface, allowing us 27 to identify features such as fault scarps and offsets. 28 Our results indicate recent activity on the fault surface, suggesting that the Piano delle Rose 29 Fault may pose a significant seismic hazard. Soil analysis has revealed that the fault surface is rela-30 tively young, estimated to be less than 400,000 years old. High-resolution topography and aeropho-31 togrammetry analyses show evidence of active tectonic deformation, indicating that the area is sus-32 ceptible to future seismic activity and corresponding risk. 33 Our study highlights the importance of integrating multiple techniques for examining fault 34 surfaces in seismic gap areas. By combining geomorphological analysis, aerophotogrammetry, 35 high-resolution topography, and soil analysis we gain a comprehensive understanding of the struc-36 ture and behavior of faults. This approach can help assess the potential for future seismic activity 37 and develop strategies for mitigating its impact.