GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 1.1 GNGTS 2023 For this reason, we first subdivided the study region (and the entire starting dataset) in the 18 macroareas related to the velocity models, then we further discretize each area (and the included events) in 100x100km2 cells, overlapped by the 80% in longitude and latitude (Fig. 1b). For these cells we repeatedly produced hypocentral locations of the same events that we merged by computing a final weighted mean location. Fig. 1: a) Macroareas defined by means of geological, tectonically and seismic evaluations for each area. b) Example of cells’ discretization. On the right, the position of cells with respect to Italy. On the left, the zoom of 4 cells’ superposition. Different colored polygons correspond to different macroareas. Fig. 2 shows a graphic example of the location’s implementation steps allowing a well constrained hypocentral locations. In the first step, we improved hypocenters resolution starting from the CLASS catalog to the double-difference one by using only absolute differential travel times; in the second step, we further enhanced the locations by combining the differential travel times computed by pickings with the cross-correlations measurements.