三维大地电磁自动建模与快速反演算法

项目名称： 三维大地电磁自动建模与快速反演算法

项目编号： No.41304110

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 天文学、地球科学

项目作者： 杨波

作者单位： 中国地质大学（武汉）

项目金额： 25万元

中文摘要： 三维(3D)大地电磁(MT)反演可以获得高精度、高分辨率、高可靠度的三维地下电性分布。因此，地球深部探测MT资料的精细解释迫切需要3D反演的支持。通常的3D反演算法面临着计算时间长、所需内存大、对实测数据反演效果差等问题，严重影响了3D反演在实测数据解释中的应用。课题拟将多种一维和二维反演(Bostick，RRI，Occam)的结果，通过融合插值，自动建立3D反演的初始模型。通过使用LU分解法直接求解正演问题的线性方程组、Footprint技术和小波变换算法压缩灵敏度矩阵、拟3D反演算法和混合反演算法等手段，提高3D MT反演算法的效率和稳定性。反演算法将基于MPI平台并行化。通过实测3D MT数据的反演解释，检验算法的实际应用效果。最终形成一套高效、可靠的3D MT反演算法。这些研究工作的开展，将为3D MT反演的实用化提供技术支撑，为深化对地球内部三维电性结构的认识，提供有效的手段。

中文关键词： 大地电磁；反演；三维；自动建模；快速算法

英文摘要： The accurate, high-resolution and reliable three-dimensional(3D) resistivity image of earth can be gotten by using 3D inversion of magnetotelluric(MT) data. It is imperative that the detailed interpretation of MT data for the deep earth be supported by 3D inversion techniques. Normal 3D MT inversion algorithm needs great amount of CPU-time and computer memory, and has poor result for real data. These shortcomings limit the application of 3D inversion for real MT data. This proposal is about to introduce two techniques. Firstly, an initial-model auto-generation method is proposed by using data fusion and interpolation algorithm from the results of 1D Bostick inversion, 2D rapid relaxation inversion(RRI), 1D/2D Occam's inversion of 3D MT data set. The built approximate model can be used as the initial-model of non-linear conjugate gradient(NLCG) inversion algorithm which is very sensitive to the start model. Secondly, quasi-3D inversion algorithm and hybrid 3D inversion algorithm are proposed to establish a fast 3D MT inversion software. The LU decomposition algorithm will be used to solve the system equation of 3D MT forward problem. The sensitivity matrix will be optimized by combining the Footprint technique and wavelet compression algorithm. In the hybrid algorithm, the Occam's inversion routine which is alway

英文关键词： Magnetotellurics；Inversion；Three-dimension；Initial model auto-generation；fast algorithm