GNGTS 2021 - Atti del 39° Convegno Nazionale

GNGTS 2021 S essione 3.2 430 The second dataset we present was acquired on a sandy beach in Bibione (Veneto region, Italy, see Figure 1b). Geologically, the beach lies between the Tagliamento river, carrying the thicker grained sands visible on the surface of the beach, and the Porto Baseleghe tidal inlet, carrying finer grained clay muds which probably lie below the sands. The acquisition parameters are the same as those used in the previously described dataset, except, in this case, for the surface-waves we used an array of 48 4.5 Hz vertical geophones with 2 m spacing. Results In Figure 2a we show, as an example, a common shot gather of the SH-wavefield acquired Kaštela, where we highlighted the first-breaks, which were picked for the travel-time tomography. Figure 2. a) Example of common shot gather, SH-wavefield. The picked first-breaks are highlighted in green. b) Result of the tomographic inversion of the SH data (bottom) and computed V S30 (top). c) Frequency- wavenumber spectrum of the data for surface-wave analysis. No dispersive event is present. d) V SV - V SH ratio