CSAMT三维交错采样有限差分数值模拟  

CSAMT 3D modeling using staggered-grid finite difference method

作　　者：邓居智[1] 谭捍东[2] 陈辉[1] 佟拓[2] 林昌洪[2] 

机构地区：[1]东华理工大学放射性地质与勘探技术国防重点学科实验室,江西抚州344000 [2]中国地质大学(北京)地球物理与信息技术学院,北京100083

出　　处：《地球物理学进展》2011年第6期2026-2032,共7页Progress in Geophysics

基　　金：国家自然科学基金(41164003;41004048);深部探测技术与实验研究国家重大科技专项(SinoProbe-03-04);江西省井冈之星青年科学家培养计划;国家科技支撑计划(2011BAB04B03)联合资助

摘　　要：系统分析大地电磁三维交错采样有限差分算法的基础上,根据可控源音频大地电磁场特征,采用将总场分解为一次场和二次场计算,一次场利用快速汉克尔变换,二次场利用数值模拟的思路.从CSAMT满足的麦克斯韦方程组积分形式出发,利用交错采样有限差分算法推导了电场和磁场的离散关系式,提出了简洁的边界条件和合理的剖分方案,所实现的CSAMT三维正演算法具有迭代速度快、收敛稳定、计算精度高等特点.通过均匀半空间和三维低阻体两个理论模型的计算结果检验了算法的正确性和计算精度,为CSAMT三维反演奠定了基础.On the basis of systems analysis the magnetotelluric 3-D modeling using staggered-grid finite difference method, the general field was decompounded into two parts with the characteristic of CSAMT field, one was the background field calculated by Fast Hankel Transform, and the other was the secondary field elicited by numerical modeling. The discrete equations of electric field and magnetic field are derived from integral format of Maxwell＇s equation using staggered-grid finite difference method. More explicit boundary conditions and reasonable dissect method were also introduced. The result shows that, the fast algorithm has high-precision and stability convergence to CSAMT 3D forward modeling. The validity and precision have been proved by a uniformity half space model and a 3 D low resistivity prism model. The efficient algorithm has setup basis for future research of 3-D CSAMT inversion.

关 键 词：CSAMT 交错采样有限差分 三维正演 边界条件 汉克尔变换 

分 类 号：P631[天文地球—地质矿产勘探]