GNGTS 2016 - Atti del 35° Convegno Nazionale

66 GNGTS 2016 S essione A matrice 3D point cloud was converted into a mesh and overlapped with the photos, manually targeting the main discontinuity planes in order to locate the fractures surfaces. The attitude of these discontinuities, expressed by dip direction and dip, was successively measured using a combination of GIS tools, integrated and verified with the field survey, and subsequently processed via the classical geometrical spatial methods using structural statistical tools (sterographic projections, histograms). The principal planes of the different fracture and fault systems were determined on the single set and density calculated using statistical distribution. The along-strike displacement versus distance of the fault plane and ground ruptures was analysed along several cross sections orthogonal to the fault strike by correlating homologous stratigraphic markers on both hanging/foot-wall blocks. The cross sections highlight slip accommodation through linkage, which has been shown to be a common fault growthmechanism in extensional settings (Cowie and Roberts, 2001). Surface ruptures related to the earthquake occurred along the slopes of Mt. Vettore, crossing the already known normal fault strands (Fig. 1). They have a continuous extent of ~10 km and consist of open cracks and vertical dislocations or warps (0.3 m maximum throw) with an orientation of N 135° (Fig. 2). The displacement is generally down-dip with a small left Fig. 1 – Virtual outcrop of the eastern slope of Mt. Vettore (a) with DEM (b), 1-m contours (c) and a detailed virtual outcrop generated by an SfM aerial survey. The dashed line indicated the fault trace. Fig. 2 – Oblique aerial panoramic photo of the western slope of Mt. Vettore. In the insert, the zenithal view of the ground cracks along the path.