UAV survey method to Monitoring and analysing geological hazards: The Case study of mud volcano of Villaggio Santa Barbara, Caltanissetta (Sicily).

All active geological processes determine effects on the soil due to different deformation processes: surface uplift and subsidence, shear lineaments with differential kinematics in relation to the source and the soils involved. Among all the active geological processes on Santa Barbara mud volcano (Caltanissetta town, Italy), represents a dangerous site because it caused, on 11 August 2008, a paroxysmal event, which determined severe damages to the infrastructures at around to 2 km the paroxysmal event. The remote sensing of surface deformation now represents a key tool for the evaluation and monitoring of the hazard. The use of unmanned aerial vehicles (UAVs) in contexts of natural danger presents three main steps for risk assessment and monitoring: pre-post event data acquisition, emergency support and monitoring. Here we present a methodology for monitoring deformation processes that may be precursors of paroxysmal events on the Santa Barbara mud volcano. Among the precursors, the lifting and development of structural features are the most important, with dimensions ranging from centimetre to decimetre. Therefore in relation to the magnitudes of the phenomena involved, the objective of this work is (going from the acquisition phase, to the SfM processing chain and the use of the M3C2-PM algorithm for the comparison between point clouds and uncertainty analysis with a statistical approach) the monitoring of deformation processes, with centimetre precision and a temporal frequency of 1-2 months, as precursor indications of hazard. [ABSTRACT FROM AUTHOR]