Preconditioner for estimation of multipole sources via full waveform inversion
Preconditioner for estimation of multipole sources via full waveform inversion
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DOI：
10.1016/j.jcp.2020.109667
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发表时间：
2020-06
期刊：
影响因子：
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通讯作者：
Mario J. Bencomo;W. Symes
中科院分区：
文献类型：
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作者：
Mario J. Bencomo;W. Symes
准确的震源表示和估计是介质-震源联合全波形反演问题的关键。我们重点讨论震源估计子问题及其困难，其中地震源是由截断的多极子序列建模的。震源全波形反演法产生了一个高度病态(潜在病态)的线性最小二乘问题，我们试图通过共轭梯度迭代求解。我们的主要贡献在于开发了一种预处理器来加速共轭梯度法在多极子震源反演中的性能。该预条件子由(分数)时间导数/积分算子组成，基于无界均匀介质中多极子波动方程的解析解。二维数值结果表明，当采用该预条件格式时，共轭梯度迭代得到了加速。
Accurate representation and estimation of seismic sources is crucial to the joint medium-source full waveform inversion problem. We focus on the source estimation subproblem and its difficulties, where seismic sources are modeled by truncated series of multipoles. The source full waveform inversion formulation results in a highly ill-conditioned (potentially ill-posed) linear least squares problem which we attempt to solve iteratively via conjugate gradient. Our main contribution lies in developing a preconditioner to accelerate the performance of conjugate gradient on multipole source inversion. The proposed preconditioner consists of (fractional) time derivative/integral operators based on analytical solutions to the wave equation with multipole sources in an unbounded, homogeneous medium. Numerical results in 2D demonstrate that the conjugate gradient iterations are accelerated when incorporating the proposed preconditioning scheme.