Год издания: 2020

Seismic ray tomography is a popular tool for reconstructing seismic velocity models from traveltime data. The problem of tomographic inversion is non-unique and requires regularization to solve it in a stable manner. It is highly non-trivial to choose between various regularization approaches or tune the regularization parameters themselves. Here we study the influence of one particular regularization parameter on the resolution and accuracy the tomographic inversion for the near-surface model building. In particular, we consider weighting of the elements of the model perturbation vector based on the reference-model values. For example, one can see that the model parameterization in terms of velocities results in reduced sensitivity for deeper anomalies as opposed to the model parameterization in terms of slownesses. We suggest another weighting that corresponds to parametrization in-between the velocity and the slowness. It results in the best quality of tomographic inversion. Our conclusions are derived from a series of synthetic tests: 2D checkboard model with varying geometry of anomalies and 2D velocity model with near-surface structure typical for West Siberia and acquisition geometry typical for 2D reflection surveys.