Simulation of the Rayleigh waves in the proximity of the scattering velocity heterogeneities. Exploring the capabilities of the microseismic sounding method

The interaction between the fundamental mode surface Rayleigh waves and the buried heterogeneities with various sizes and different velocity contrasts was studied on base numerical simulation. The field of surface oscillations in the proximity of the scattering heterogeneities was computed as a function of frequency. The synthetic seismograms were used for numerical simulation of the microseismic sounding technology proposed earlier, implying that the solution of the inverse problem for the structure of the medium containing inclusions can be derived from the information contained in the ambient microseismic field. It is assumed that the depth of the layer to be reconstructed is linked with the frequency of the microseisms by a simple relation with the help of a numerical coefficient equal to 0.4–0.5. The combined results of the simulation of a direct problem together with the simple inverse problem solution show that the microseismic sounding technique ensures adequate estimation of the medium structure. Previously, the technology was based on the experimental data only and was phenomenological in character. Some relations between the velocity parameters of the original model heterogeneities and their reconstructed images were also studied.