GNGTS 2017 - 36° Convegno Nazionale

the real-data source frequency content, we also attempted a source-wavelet estimation. The signature of the real source was obtained using a matching-filter estimation of the simulated and real data (e.g. Pratt, 1999). In Fig. 2c we show the results obtained with this new estimated source. Discussion, conclusions and perspectives. The comparison between the real-data and the synthetic seismograms obtained by propagating the Ricker source in the model deduced from the DCs analysis shows a good similarity among the two datasets; there is an even greater similarity between the field seismogram and the one obtained from the numerical simulation when recovering the source time function. This shows that the initial model obtained from LCI of DCs appears to be a good candidate for further FWI. Therefore, according to these preliminary observations, we could send out a positive prediction regarding the possibility to obtain accurate results from the FWI of this near-surface target; nevertheless, managing high amplitudes variations between surface and body waves will be a challenge. As a short-time perspective, we are planning to perform the estimation of the first FWI gradient before inverting the 2D data using the full 3D elastic FWI. Long-time perspectives will involve the analysis of the 3D field data and FWI. Acknowledgements We would like to thank the SEISCOPE consortium for providing the SEM3D code and the CIMENT mesocentre for allowing the access to the computational resources. References Bergamo, P., Boiero, D. and Socco, L.V. (2012): Retrieving 2D structures from surface-waves data by means of space- varying windowing. Geophysics, 77(4), EN39-EN51. Fichtner, A. (2011): Full Seismic Waveform modelling and Inversion. Springer Science & Business Media, 343 pp. Pratt, R.G. (1999): Seismic waveform inversion in the frequency domain, Part 1: Theory and verification in a physical scale model. Geophysics, 64 (3):888-901. Socco, L.V., Boiero, D., Foti, S. and Wisén, R. (2009): Laterally constrained inversion of ground roll from seismic reflection records. Geophysics, 74(6): G35-G45. Tarantola, A. (2005): Inverse problem theory and methods for model parameter estimation, 2 nd edn. Society for Industrial and Applied Mathematics, Philadelphia, PA (2005). Trinh, P. T., Brossier, R., Métivier, L., Tavard, L. and Virieux, J. (2017a): Efficient 3D elastic FWI using a spectral- element method. In 87th SEG Conference and Exhibition 2017, Houston. Trinh, P. T., Brossier, R., Métivier, L., Virieux, J. and Wellington, P. (2017b): Bessel smoothing filter for spectral element mesh. Geophysical Journal International, 209 (3): 1489-1512. Trinh, P. T., Brossier, R., Métivier, L., Virieux, J. and Wellington, P. (2017c): Structure-smoothing Bessel filter for finite element mesh: Application on 3D elastic FWI. In 79th EAGE Conference and Exhibition 2017, Paris. Virieux, J. and Operto, S. (2009): An overview of full-waveform inversion in exploration geophysics. Geophysics, 74(6): WCC1-WCC26. Fig. 2 - Seismograms related to the Shot nr. 2. a: field data; b:synthetic data obtained by propagating the Ricker source; c:synthetic data obtained by propagating the real (estimated) source. 736 GNGTS 2017 S essione 3.3