GNGTS 2017 - 36° Convegno Nazionale

400 GNGTS 2017 S essione 2.2 On the other hand, the three sites where we observe significant differences between noise and earthquake results remind us that much care must be taken when studying site effects. The results of this work indicate that in mountainous regions where the local geology is far from a horizontally layered structure, the H/V spectral ratio alone is not sufficient to characterize the site response. More exhaustive analysis need to be performed for a satisfying interpretation of the results obtained from seismic noise. It is also very important the fact that earthquake HVSR curves at sites with marked topographical effects do not show the same peaks, and often have lower amplitude. This result suggests overstimated site effects given by the noise HVSR. References Bonilla, L. F., H. J. Steidl, G. T. Lindley, A. G. Tumarkin, and R. Archuleta; 1997: Site amplification in the San Fernando Valley, California: Variability of the site-effect estimation using the S-wave, coda, and H/V methods, Bull. Seismol. Soc. Am. 87, no. 3, 710–730. Cantore, L., A. Oth, S. Parolai, and D. Bindi; 2011: Attenuation, source parameters and site effects in the Irpinia– Basilicata region (southern Apennines, Italy). Journal of Seismology , 15 (2), 375-389. Cinti, F. R., M. Moro, D. Pantosti, L. Cucci, and G. D’Addezio; 2002: New constraints on the seismic history of the Castrovillari fault in the Pollino gap (Calabria, southern Italy) , J. Seismol. 6, 199–217. Clemente-Chavez, A., F. R. Zúñiga, J. Lermo, A. Figueroa-Soto, C. Valdés, M. Montiel, O. Chavez, and M. Arroyo; 2014: On the behavior of site effects in central Mexico (the Mexican volcanic belt. Natural Hazards and Earth System Sciences, 14(6), 1391. Cultrera, G., E. D’Alema, S. Amoroso, B. Angioni, P. Bordoni, L. Cantore, ... and G. Di Giulio; 2016: Site effect studies following the 2016 Mw 6.0 Amatrice earthquake (Italy): the Emersito Task Force activities. Annals of Geophysics , 59 . Formisano, L.A., M. La Rocca, E. Del Pezzo, D. Galluzzo, C. Fischione, and R. Scarpa; 2012: Topography effects in the polarization of earthquake signals: a comparison between surface and deep recordings. Bollettino di Geofisica Teorica ed Applicata , 53 (4), 471-484. I. Guerra, A. Borghi, S. Del Mese, F. Filice, A. Gervasi, A. Mendicelli, L. Seeber, G. Stellato; 2015: Contribution to the Seismotectonic Studies in the Area at the Calabria-Lucania Border by Means of Geophysical Monitoring and Analyses, Atti 34° Conv. Ann. Gr. Naz. Geofis. Terra Solida, Trieste, 17-19 Novembre 2015. Nakamura, Y.; 1989: A method for dynamic characteristics estimations of subsurface using microtremors on the ground surface, Q. Rep. Railway Tech. Res. Inst. Japan 30, 25–33. Panzera, F., G. Lombardo, E. Longo, H. Langer, S. Branca, R. Azzaro, V. Cicala, and Trimarchi, F. (2017a). Exploratory seismic site response surveys in a complex geologic area: a case study from Mt. Etna volcano (southern Italy). Natural Hazards , 86 (2), 385-399. Pischiutta, M., G. Cultrera, A. Caserta, L. Luzi, and A. Rovelli; 2010: Topographic effects on the hill of Nocera Umbra, central Italy. Geophysical Journal International, 182(2), 977-987. Pischiutta, M., M. Fondriest, M. Demurtas, F. Magnoni, G. Di Toro, A. Rovelli (2017). Structural control on the directional amplification of seismic noise (Campo Imperatore, central Italy) . Earth and Planetary Science Letters 471, 10–18. Rigano, R., F. Cara, G. Lombardo, and A. Rovelli; 2008: Evidence for ground motion polarization on fault zones of Mount Etna volcano. Journal of Geophysical Research : Solid Earth, 113(B10). Rovida, A., R. Camassi, P. Gasperini, and M. Stucchi; 2011: CPTI11, la versione 2011 del Catalogo Parametrico dei Terremoti Italiani , Milano, Bologna. Tertulliani, A., and L. Cucci; 2014: New insights on the strongest historical earthquake in the Pollino region (southern Italy) , Seismol. Res. Lett. 85, 743–751, doi: 10.1785/0220130217.