TY - JOUR

T1 - Efficient traveltime solutions of the acoustic TI eikonal equation

AU - Waheed, Umair bin

AU - Alkhalifah, Tariq Ali

AU - Wang, Hui

N1 - KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: We thank KAUST for financial support. We are also grateful David Ketcheson for useful discussions on the direct solver. We also thank BP for releasing the benchmark synthetic model.

PY - 2015/2

Y1 - 2015/2

N2 - Numerical solutions of the eikonal (Hamilton-Jacobi) equation for transversely isotropic (TI) media are essential for imaging and traveltime tomography applications. Such solutions, however, suffer from the inherent higher-order nonlinearity of the TI eikonal equation, which requires solving a quartic polynomial for every grid point. Analytical solutions of the quartic polynomial yield numerically unstable formulations. Thus, it requires a numerical root finding algorithm, adding significantly to the computational load. Using perturbation theory we approximate, in a first order discretized form, the TI eikonal equation with a series of simpler equations for the coefficients of a polynomial expansion of the eikonal solution, in terms of the anellipticity anisotropy parameter. Such perturbation, applied to the discretized form of the eikonal equation, does not impose any restrictions on the complexity of the perturbed parameter field. Therefore, it provides accurate traveltime solutions even for models with complex distribution of velocity and anisotropic anellipticity parameter, such as that for the complicated Marmousi model. The formulation allows for large cost reduction compared to using the direct TI eikonal solver. Furthermore, comparative tests with previously developed approximations illustrate remarkable gain in accuracy in the proposed algorithm, without any addition to the computational cost.

AB - Numerical solutions of the eikonal (Hamilton-Jacobi) equation for transversely isotropic (TI) media are essential for imaging and traveltime tomography applications. Such solutions, however, suffer from the inherent higher-order nonlinearity of the TI eikonal equation, which requires solving a quartic polynomial for every grid point. Analytical solutions of the quartic polynomial yield numerically unstable formulations. Thus, it requires a numerical root finding algorithm, adding significantly to the computational load. Using perturbation theory we approximate, in a first order discretized form, the TI eikonal equation with a series of simpler equations for the coefficients of a polynomial expansion of the eikonal solution, in terms of the anellipticity anisotropy parameter. Such perturbation, applied to the discretized form of the eikonal equation, does not impose any restrictions on the complexity of the perturbed parameter field. Therefore, it provides accurate traveltime solutions even for models with complex distribution of velocity and anisotropic anellipticity parameter, such as that for the complicated Marmousi model. The formulation allows for large cost reduction compared to using the direct TI eikonal solver. Furthermore, comparative tests with previously developed approximations illustrate remarkable gain in accuracy in the proposed algorithm, without any addition to the computational cost.

UR - http://hdl.handle.net/10754/564030

UR - http://arxiv.org/abs/arXiv:1311.4203v1

UR - http://www.scopus.com/inward/record.url?scp=84911397046&partnerID=8YFLogxK

U2 - 10.1016/j.jcp.2014.11.006

DO - 10.1016/j.jcp.2014.11.006

M3 - Article

VL - 282

SP - 62

EP - 76

JO - Journal of Computational Physics

JF - Journal of Computational Physics

SN - 0021-9991

ER -