GNGTS 2014 - Atti del 33° Convegno Nazionale

38 GNGTS 2014 S essione 3.1 an unknown orientated noise source (in this case toward y direction), which does not admit common linear array ReMi treatment. The combination of the results of two L-shaped linear arrays can overcome the limitations of ReMi in cases of these strongly directional sources. The use of LeMi L-shaped array approach allows to detect the orientation of the predominant source and correctly estimate Ktrue and the related phase velocities (Fig. 3). In this test site L-shaped array results proved to be in agreement with the controlled source test results of Fig. 2 – Controlled source f-k spectrum for the L shaped array, (branch x and y) and dispersion curve obtained averaging the results of the two branches, for the real dataset collected in Badia Polesine (Ro). Fig. 3 – F-k maxima picking for the N-S (y) branch (blue); E-W (x) branch (red) and combination of the two apparent wavenumbers (EW and NS) to estimate the Ktrue values. In right panel are visible the relative dispersion curves in the Phase velocity/ frequency.