GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 3.2 GNGTS 2024 heightened P velocites are observed primarily in the southernmost part of the hill, approximately 30 meters below the topographic surface. Notably, the structure directly beneath the centre of the old village exhibits comparatvely lower P velocites. The region enclosed by the perimeter of Line 1 displays a heterogeneous distributon of P and S velocites, with the excepton of the high-velocity zone on the western side, aligning with the elevated velocites detected beneath Line 2. Regarding S velocites, the reliability of the inversion is compromised by increased noise compared to P data, exacerbated by lateral events interfering with the frst break signals used for inversion. Despite these challenges, an analysis of the Vp/Vs rato maps (Fig. 4) reveals a discernible patern showcasing alternatng low and high values, following bands oriented in a north-south directon. This patern broadly corresponds to the strike values of subsurface formatons identfed in the area. Acknowledgments The authors thank the entre OGS acquisiton group for the professional level demonstrated in the tough acquisiton task, the Marche Region Special Reconstructon Ofce (USR) for the permission to publish these data and results, Prof. Carlo G. Lai (Eucentre Foundaton, Pavia), Prof. Alessandro Pagliaroli and Prof. Alberto Pizzi of the University of Chiet for their advice and valuable suggestons. References Böhm G., Rossi G., Vesnaver A.; 1999: Minimum-tme ray tracing for 3-D irregular grids. Journal of seismic exploraton, 8, 117-131. Stewart R.; 1991: Exploraton Seismic Tomography: Fundamentals. Course note series, vol. 3, S. N. Domenico, Editor. SEG - Society of Exploraton Geophysicists. DOI: htps://doi.org/10.1190/1.9781560802372. Vesnaver A., Böhm G.; 2000: Staggered or adapted grids for seismic tomography? The Leading Edge 19(9), 944-950. DOI: htps://doi.org/10.1190/1.1438762. Corresponding author: gbohm@ogs.it