GNGTS 2022 - Atti del 40° Convegno Nazionale

236 GNGTS 2022 Sessione 2.1 amplification is derived from the European Engineering Strong-Motion (ESM) dataset (Luzi et al. , 2020) as the site-to-site residuals ( δ S2S s ) derived from a simple GMM following the method of Kotha et al. (2018, 2020) and Weatherill et al. (2020). For each proxy we derive a simple site amplification model based on linear regression (black lines in Fig. 2) and evaluate the performance of each model. The results show that the geomorphological sedimentary thickness performs better than or equally well as the inferred V S30 and topographic slope. We therefore argue that the inferred geomorphological sedimentary thickness from the Pelletier et al., 2016 model is a promising new alternative to traditional inferred proxies for predicting site amplification on a regional or global level and capture the epistemic uncertainty associated to the prediction of site amplification for large scale seismic hazard or risk studies. Fig. 2 - The linear regression (black lines) and correlation coefficient r between the empirical site amplification δ S2S s for frequency f = 1.062 Hz and the inferred V S30 (top) and topographic slope (middle) and the geomorphological sedimentary thickness (bottom) at stations from the European Engineering Strong-Motion (ESM) dataset. Acknowledgments. The authors are grateful to Jean Braun for valuable discussion and explanation on regolith. This research is funded by the European Commission, ITN-Marie Sklodowska-Curie New Challenges for Urban Engineering Seismology URBASIS-EU project, under Grant Agreement 813137. References Kotha, S.R., Cotton, F., and Bindi, D. (2018). A new approach to site classification: mixed-effects ground motion prediction equation with spectral clustering of site amplification functions.  Soil Dynamics and Earthquake Engineering, 110, 318-329. https://doi.org/10.1016/j.soildyn.2018.01.051. Kotha, S.R., Weatherill, G., Bindi, D. and Cotton, F. (2020). A regionally-adaptable ground-motion model for shallow crustal earthquakes in Europe . Bull Earthquake Eng 18, 4091–4125 https://doi.org/10.1007/s10518-020-00869-1. Lemoine, A., Douglas, J., and Cotton, F. (2012). Testing the Applicability of Correlations between Topographic Slope and VS 30  for Europe.  Bulletin of the Seismological Society of America; 102 (6): 2585–2599. doi: https://doi. org/10.1785/0120110240. Luzi L., Lanzano G., Felicetta C., D’Amico M. C., Russo E., Sgobba S., Pacor, F., and ORFEUS Working Group 5 (2020). Engineering Strong Motion Database (ESM) (Version 2.0) . Istituto Nazionale di Geofisica e Vulcanologia (INGV). https://doi.org/10.13127/ESM.2. Pelletier, J.D., Broxton, P.D., Hazenberg, P., Zeng, X., Troch, P. A., Niu, G.-Y., Williams, Z., Brunke, M. A., and Gochis, D. (2016), A gridded global data set of soil, immobile regolith, and sedimentary deposit thicknesses for regional and global land surface modeling , J. Adv. Model. Earth Syst., 8, 41– 65, doi:10.1002/2015MS000526. Weatherill G., Kotha S. R., and Cotton F. (2020). Re-thinking site amplification in regional seismic risk assessment. Earthquake Spectra., 36:274-297. doi:10.1177/8755293019899956. Wald, D. J., Allen, T. I. (2007). Topographic Slope as a Proxy for Seismic Site Conditions and Amplification . Bulletin of the Seismological Society of America, 97 (5): 1379–1395. doi: https://doi.org/10.1785/0120060267.