GNGTS 2021 - Atti del 39° Convegno Nazionale

GNGTS 2021 S essione 2.1 158 strength parameters by performing a pseudostatic limit equilibrium analysis assuming an infinite slope scheme and considering both drained and undrained conditions for the soil behaviour. We assumed as seismic input the E-W component of the acceleration time history associated to the December 26, 2018 M w 4.9 earthquake, registered at the PTR station (Fig. 1a), with this compo- nent being the most energetic (PGA ≈ 0.01g) and perfectly aligned with the DGSD sliding plane orientation and slip direction. For drained conditions, the critical friction angle ( f c ) ranges between 2.4 and 2.8 degrees, with a median value of approximately 2.5. These values are not compatible with the experi- mental distribution of f , ranging between 18 and 27 degrees. For undrained conditions, the critical undrained cohesion ( c u,c ) ranges between 30 and 200 kPa, with a median value of ap- proximately 132 kPa. Such values are consistent with the experimental distribution of c u shown in Fig. 2c. Conclusions The interplay between volcano-tectonic earthquakes and the triggering of non-catastro- phic landslide movement has been investigated by applying a multidisciplinary approach. Geological and geomorphological analyses provided evidence of a previously unknown pa- leo-landslide located 5 km west of Paternò village with an overall extent of approximately 3.40 km 2 . InSAR data show that the landslide mass, which was in a dormant phase, was reac- tivated during the Etna volcano eruption and the related seismic swarm. Analytical inversion of InSAR data identified the geometry and kinematics of the potential sliding surface, whose geometry and position are in accordance with geological and geomorphological findings. The back-analysis of the observed ground displacements confirmed that the landslide mass reactivated during the light-to-moderate seismic shaking caused by the December 26 M w 4.9 earthquake 25 km away. The earthquake caused undrained instability of the landslide and ground displacement. References Albano, M., Saroli, M., Montuori, A., Bignami, C., Tolomei, C., Polcari, M., Pezzo, G., Moro, M., Atzori, S., Stramondo, S., Salvi, S.; 2018: The Relationship between InSAR Coseismic Deformation and Earthquake- Induced Landslides Associated with the 2017 Mw 3.9 Ischia (Italy) Earthquake . Geosciences 8 , 303. https://doi.org/10.3390/geosciences8080303 Bignami, C., Salvi, S., Albano, M., Guglielmino, F., Tolomei, C., Atzori, S., Trasatti, E., Polcari, M., Puglisi, G., Stramondo, S.;2019: Multi-Hazard Analysis of Etna 2018 Eruption by Sar Imaging , in: IGARSS 2019 - 2019 IEEE International Geoscience and Remote Sensing Symposium. IEEE, pp. 9314–9317. https://doi. org/10.1109/IGARSS.2019.8898695 Bonforte, A., Guglielmino, F., Puglisi, G.; 2019: Large dyke intrusion and small eruption: The December 24, 2018 Mt. Etna eruption imaged by Sentinel-1 data . Terra Nova 31 , 405–412. https://doi.org/10.1111/ ter.12403 De Novellis, V., Atzori, S., De Luca, C., Manzo, M., Valerio, E., Bonano, M., Cardaci, C., Castaldo, R., Di Bucci, D., Manunta, M., Onorato, G., Pepe, S., Solaro, G., Tizzani, P., Zinno, I., Neri, M., La- nari, R., Casu, F.; 2019: DInSAR Analysis and Analytical Modeling of Mount Etna Displacements: The December 2018 Volcano‐Tectonic Crisis . Geophys. Res. Lett. 46 , 5817–5827. https://doi. org/10.1029/2019GL082467 Di Naccio, D., Kastelic, V., Carafa, M.M.C., Esposito, C., Milillo, P., Di Lorenzo, C.; 2019: Gravity Versus Tecto- nics: The Case of 2016 Amatrice and Norcia (Central Italy) Earthquakes Surface Coseismic Fractures . J. Geophys. Res. Earth Surf. 124 , 994–1017. https://doi.org/10.1029/2018JF004762 Newmark, N.M.; 1965: Effects of Earthquakes on Dams and Embankments . Géotechnique 15 , 139–160. https://doi.org/10.1680/geot.1965.15.2.139