| 磁化率对大地电磁响应的影响研究 |
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| 引用本文： | 李学民,曹俊兴.磁化率对大地电磁响应的影响研究[J].地球物理学报,2005,48(4):947-950. |
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| 作者姓名： | 李学民 曹俊兴 |
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| 作者单位： | 成都理工大学油气藏地质及开发工程国家重点实验室，成都610059 |
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| 基金项目： | 国家自然科学基金项目(40274019). |
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| 摘 要： | 本文推导了物质的磁化率大于自由空间的情况下的二维大地电磁(MT)正演计算公式. 利用有限差分法实现了其正演计算，获得了电磁场的分布. 详细地讨论了磁化率对MT响应的影响，证实了磁化率主要影响磁场信号的同相分量，而对磁场信号的异相分量和电场信号的影响比较弱. 当磁化率κ≥001时，在某些低频点的视电阻率值可以增加5Ωｍ左右，并且随着磁化率增加，这种增加的幅度显著增大；而对阻抗相位的影响则非常小. 新的认识为高磁化率物质存在的地区观测到的MT数据解释提供一种新的研究思路.
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| 关 键 词： | 大地电磁响应 同相分量 异相分量 磁化率 |
| 文章编号： | 0001-5733(2005)04-0947-04 |
| 收稿时间： | 2004-07-27 |
| 修稿时间： | 2005-03-18 |
A study on the influence of magnetic susceptibility upon MT response |
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| LI Xue-min,CAO Jun-xing.A study on the influence of magnetic susceptibility upon MT response[J].Chinese Journal of Geophysics,2005,48(4):947-950. |
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| Authors: | LI Xue-min CAO Jun-xing |
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| Institution: | State Laboratory of Oil/Gas Reservoir Geology and Exploitation,Chengdu University of Technology, Chengdu 610059, China |
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| Abstract: | In the case that the susceptibility of material is greater than that of free space, we deduce the forward modeling formula of 2_D magnetotelluric with resisitivity and magnetic susceptibility as model parameters. Using the finite difference method we calculate the distribution of the electromagnetic field. We analyze the influence of the magnetic susceptibility on MT responses in detail and confirm that it mainly affects in_phase components of the magnetic field and hardly affects both the quadrature components and the electric field components. When the magnetic susceptibility is κ≥001, the apparent resistivity may increase by about 5Ωm at some low frequencies, and the amplitudes of change increase observably with growing magnetic susceptibility. Furthermore, magnetic susceptibility has little effect on impedance phase. In a word, this study provides a new study idea to interpret the observed MT data in areas of high magnetic susceptibility. |
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| Keywords: | MT response In_phase components Quadrature components Magnetic susceptibility |
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