Towards an application of an elastic FWI for a measurement below ground in a crystalline environment

The demand towards a high resolution image of seismic measurements rises in every sphere of interest. We want to test an elastic full waveform inversion approach for inverting for crystalline host rock for future application below ground. This will decrease the safety and investment risks for underground developments. We performed seismic measurements with multi-component receivers using transmission geometry in the GFZ Underground Lab in the research and education mine ”Reiche Zeche” of the TU Bergakademie Freiberg. A 2-D elastic full waveform tomography is applied to gain a high-resolution velocity model by using only the waveform of the first arrival P-wave. For this approach, based on the field measurement geometry, a synthetic test investigated the applicability of the inversion. A preprocessing flow was applied on the synthetic data. As the true model, a random scattered velocity model which represent the crystalline rock was used to estimate the possible resolution of the inversion. The starting model was obtained from a first arrival travel time tomography. After 250 iterations, the waveforms match almost perfectly. Also, the velocity model was reconstructed very well. ... mehrThe unresolved structures are in the range of or even smaller than the smallest wavelength used for the inversion. Therefore, our preprocessing approach for a crystalline rock medium by only considering the P-wave arrivals is suitably for a high resolution image compared to other inversion schemes.