GNGTS 2022 - Atti del 40° Convegno Nazionale

164 GNGTS 2022 Sessione 1.3 laboratory. Furthermore, the morphoscopic analyses evidenced quartz grains of clear marine origin and therefore cannot be current continental deposits. These sands, in addition to being aligned along the fracture and limited in circular shapes, are found in correspondence of depressed areas with respect to the surrounding morphology. Based on these data, we hypothesize that these sands come from the subsoil. The uprising of these sands could be a signal of a seismic-induced structure and could be due to the fluidification of the soil linked to the seismic shaking and / or to the uprising of sandy material due to density difference caused by compression. From the seismostratigraphic section, obtained from the MASW and HVSR inversions and joint-interpretation, an abrupt slope break of layers is noted (Fig. 3b). Two contributing causes have been hypothesized for this slope variation: 1: An inherited morphology and therefore a paleo-structure that produces unconformity between the first layer and the underlying one; 2: The presence of a discontinuity in the subsoil that is not visible on the surface. Fig. 3 - a) Example of one of the fractures; b) Seismostratigraphic section. The multi-temporal interferometric analysis show excessive displacement velocities. These results were not considered reliable as, with the values obtained, there should be much larger fractures than those observed in situ. The unreliability of the products is due to a limitation of the interferometric technique, or the difficulty of operating in a predominantly natural area. Conclusion. This multidisciplinary study suggests that the genesis of open fractures in the study area is directly or indirectly related to the seismic activity. Each single technique used highlighted elements that, in order to be proven, had to be compared with all the results. Evidence of gravitational phenomena, absent in the official Italian hydrogeological database (P.A.I.), were observed, which should be considered in assessing the hazard of the area. Furthermore, the different seismic responses of the area upstream and downstream of the main morphostructural feature should be taken into consideration for any engineering works to be carried out within the area. References Boggero A., Zaupa S. and Guarneri I.; 2011: Protocollo di campionamento ed analisi granulometrica di sedimenti lacustri. Progetto LIFE+ 2008 ENV/IT/000413 INHABIT. Report CNR-ISE 2011, 14 pp. Bonnefoy-Claudet S., Cotton F. and Bard P-Y.; 2006: The nature of noise wavefield and its applications for site effects studies. A literature review . Earth-Science reviews, vol. 79., pp. 205-227. Ferretti A., Monti-Guarneri A., Prati C. and Rocca F.; 2007: InSAR Principles: Guidelines for SAR Intrferometry Processing and Interpretation. ESA Publications, TM-19. ISBN: 92-9092-233-8. Nakamura Y.; 1989: A method for dynamic characteristics estimation of subsurface usig microtremor on the ground surface. Quaterly report Railway Tech. Res. Inst., Vol. 30, n.1, ISSN: 0033-9008. Pepe A. and Sansoti E.; 2005: On the generation of ERS/ENVISAT DInSAR time-series via the SBAS technique. Iee Geoscience and remote sensing letters, vol.2, n.3, pp. 265-269. Powers M. C.; 1953: A new roundness scale for sedimentary particles . Journal of Sedimentary Petrology, Vol. 23, n. 2., pp. 117-119.