3-D inversion of magnetic data
3-D inversion of magnetic data
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DOI：
10.1190/1.1443968
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发表时间：
1996-04
期刊：
影响因子：
3.3
通讯作者：
Yaoguo Li;D. Oldenburg
中科院分区：
文献类型：
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作者：
Yaoguo Li;D. Oldenburg
我们提出了一种反演表面磁数据以恢复 3D 磁化率模型的方法。为了让模型具有最大的灵活性来表示地质真实结构，我们将 3D 模型区域离散化为一组矩形单元，每个单元都具有恒定的磁化率。单元格的数量通常远远大于可用数据的数量，因此我们解决了一个不确定的问题。通过最小化由模型目标函数和数据失配组成的全局目标函数来获得解决方案。该算法可以通过使用一个或多个适当的加权函数将先验信息合并到模型目标函数中。反演模型可以是磁化率或其对数。如果选择敏感性，则施加正约束以减少非唯一性并保持物理可实现性。我们的算法假设没有剩磁，并且磁性数据仅由感应磁化产生。所有最小化均采用子空间方法进行，其中每次迭代仅使用少量搜索向量。这避免了直接求解大型方程组的需要，因此可以在桌面工作站上求解具有许多单元的地球模型。该算法在综合示例和现场数据集上进行了测试。
We present a method for inverting surface magnetic data to recover 3-D susceptibility models. To allow the maximum flexibility for the model to represent geologically realistic structures, we discretize the 3-D model region into a set of rectangular cells, each having a constant susceptibility. The number of cells is generally far greater than the number of the data available, and thus we solve an underdetermined problem. Solutions are obtained by minimizing a global objective function composed of the model objective function and data misfit. The algorithm can incorporate a priori information into the model objective function by using one or more appropriate weighting functions. The model for inversion can be either susceptibility or its logarithm. If susceptibility is chosen, a positivity constraint is imposed to reduce the nonuniqueness and to maintain physical realizability. Our algorithm assumes that there is no remanent magnetization and that the magnetic data are produced by induced magnetization only. All minimizations are carried out with a subspace approach where only a small number of search vectors is used at each iteration. This obviates the need to solve a large system of equations directly, and hence earth models with many cells can be solved on a deskside workstation. The algorithm is tested on synthetic examples and on a field data set.