| Abstract: | Full Waveform Inversion (FWI see 1]) has capability to identify the velocity field of a domain with a good precision. Its power comes from the fact that this approach does not only try to fit travel times of waves, but it tries to fit the whole seismogram. This work is about the application of acoustic full waveform inversion to 2D and 3D tunnel models. The necessary boundary conditions are applied to the models and the acoustic equation is solved by higher-order Finite Elements Method. The Conjugate Gradient (CG) method is utilized to minimize the misfit function. The results were verified with synthetic models. The synthetic tunnel models contain few bodies with different shapes and locations. Starting from a homogeneous velocity field, the synthetic model is sought over iterations. To avoid the ill-posedness, the locations and numbers of the source and receiver points have to be successfully chosen. Apart from this, the frequency set has also to be carefully constructed. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) |
