In the field of geophysics, although the first-order Rytov approximation is widely used, the higher-order approximation is seldom discussed. From both theoretical analysis and numerical tests, the accumulated phase error introduced in the first-order Rytov approximation cannot be neglected for long range propagation and strong velocity perturbation. To address the problem, we have developed a novel method to calculate the higher-order Rytov series iteratively. Specifically, we are focused on the improving the phase accuracy of the forward scattered wavefield, especially for the large-scale and strong-perturbation case. Although the convergence of the proposed method has not been proved mathematically, numerical examples demonstrated that our method can produce an improved accuracy for traveltime (phase) prediction, even for strong velocity perturbation cases. However, in the presence of multi-arrivals phenomenon, the equivalent scattering source should be handled carefully due to the multi-directions of the wavefield. Further investigations should be done to improve the applicability of the proposed method.
Presentation Date: Monday, October 15, 2018
Start Time: 1:50:00 PM
Location: Poster Station 15
Presentation Type: Poster