“…In the same context, innovative strategies are needed for preconditioning the inversion in order to extract longwavelength features. Acquisition-based methods have recently been proposed in order to improve the lowfrequency part of the spectrum (e.g., Farouki et al, 2011;Moldoveanu et al, 2012). In addition, several strategies have been proposed in order to retrieve the long wavelength features of the velocity models within the FWI framework (e.g., Kelly et al, 2010;Xu et al, 2012;Zhou et al, 2012).…”