Active method to detect and analyze seismic signals, which provides to generate an artificial vibration by means of a source and to use at least one at least bi-axial geophone to detect and record seismic signals that comprise at least the Rayleigh wave produced by the source of artificial vibration in a predefined position with respect to the geophone, characterized in that said method provides to jointly analyze at least the group-velocity frequency spectrum of the radial component (C r), the group-velocity frequency spectrum of the vertical component (C v) and the Spectral Ratio, Radial-to-Vertical Spectral Ratio, RVSR, between the radial component (C r) and the vertical component (C v), which defines the ellipticity of the produced Rayleigh waves, wherein said method provides further to carry out a joint inversion using at least the radial component (Cr), the vertical component (Cv) and the spectral ratio, RVSR, which defines the ellipticity of the produced Rayleigh waves, in order to define the shear-wave velocity (Vs) profile, wherein said inversion is based on the assessment of the misfit, or deviation between recorded seismic signals data and synthetic signals derived from a predefined mathematical model, wherein the joint inversion is based on at least three separate objective functions: - the misfit or deviation of the group-velocity frequency spectrum of the vertical component (C v) of the Rayleigh wave; - the misfit or deviation group-velocity frequency spectrum of the radial component (C r) of the Rayleigh wave; - the misfit or deviation of the RVSR that expresses the ellipticity of the Rayleigh wave; further wherein the inversion is carried out according to a multi-objective joint modality, wherein the at least three separate objective functions are simultaneously optimized and which does not require any data interpretation by the user, and which provides: i) to consider a series of mathematical subsurface models of the original subsurface; ii) to generate the relative synthetic seismograms; iii) to consider, by means of the synthetic seismograms, two synthetic traces, of which at least one relates to the vertical component (C v) and at least one relates to the radial component (C r) of the Rayleigh wave; iv) to determine, for both the synthetic traces, relating to the vertical component (C v) and the radial component (C r), the group-velocity frequency spectra and, from the corresponding Radial-to-Vertical Spectral Ratio, the ellipticity of the Rayleigh waves; v) to compare the synthetic data of point iv) with at least the group-velocity frequency spectra and the ellipticity of the Rayleigh waves, RVSR, of the corresponding traces of the seismic signals recorded on the field in order to determine the misfit, or deviation; vi) to perform a multi-objective optimization of the obtained misfits. - the misfit or deviation of the group-velocity frequency spectrum of the vertical component (C v) of the Rayleigh wave; - the misfit or deviation group-velocity frequency spectrum of the radial component (C r) of the Rayleigh wave; - the misfit or deviation of the RVSR that expresses the ellipticity of the Rayleigh wave; i) to consider a series of mathematical subsurface models of the original subsurface; ii) to generate the relative synthetic seismograms; iii) to consider, by means of the synthetic seismograms, two synthetic traces, of which at least one relates to the vertical component (C v) and at least one relates to the radial component (C r) of the Rayleigh wave; iv) to determine, for both the synthetic traces, relating to the vertical component (C v) and the radial component (C r), the group-velocity frequency spectra and, from the corresponding Radial-to-Vertical Spectral Ratio, the ellipticity of the Rayleigh waves; v) to compare the synthetic data of point iv) with at least the group-velocity frequency spectra and the ellipticity of the Rayleigh waves, RVSR, of the corresponding traces of the seismic signals recorded on the field in order to determine the misfit, or deviation; vi) to perform a multi-objective optimization of the obtained misfits.