GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 3.2 ___ GNGTS 2023 Bedrock depth and Weighted average velocity from surface waves dispersion and H/V curves without inversion C. Comina 1 , G. Di Chiara 1 and S. Foti 2 1 Dipartimento di Scienze della Terra, DST, Università degli studi di Torino, Torino (IT) 2 Dipartimento di Ingegneria Strutturale, Edile e Geotecnica, DISEG, Politecnico di Torino, Torino (IT) In this note we evaluate a workflow for the direct combined determination of bedrock depth (h) and weighted average shear wave velocity till that depth (Vs,h) from surface waves dispersion and H/V curves. The approach is based on the use of a wavelength-depth transform of the surface waves dispersion curve (W-D transform, Socco et al., 2017; Passeri et al., 2021; Comina et al., 2022) which provides and approximate Vs,h profile (Figure 1a). This profile is then transformed in a relationship expressing different possible values of fundamental frequencies, f, at any depth (Figure 1b). This relationship can be used in conjunction with resonance frequency information (f0) from H/V curve to locate the depth of the bedrock h and consequently the weighted average shear wave velocity till that depth Vs,h (Figure 1).