Model parameter design for modeling surface topography in VTI elastic finite-difference near-surface simulations

What is it about?

for the near-surface modeling, the implementation of free-surface boundary condition and non-flat topography representation are two main obstacles preventing the effectiveness of FD methods. To address these two issues in the VTI anisotropic scenarios, we present a simple and efficient method for the discrete model design which can be easily applied to the conventional Cartesian grid FD modeling. The proposed method involves: 1) the parameter-averaging method for implicitly implementing the stress-free condition by a modification of model anisotropy parameters near the (non-) flat free-surface boundary; 2) an independent wavefield superposition with modeling results of different parameter configurations to accurately represent the rugged topography and significantly reduce the staircase diffractions caused by a staircase approximation of continuous surface in the Cartesian grid discretization.

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Photo by Nick Fewings on Unsplash

Photo by Nick Fewings on Unsplash

Why is it important?

From the aspect of computational efficiency, it is more promising in practical applications due to the use of wavefield superposition strategy in this method which does not require finer spatial sampling to eliminate the staircase diffractions.