摘要
基于电磁理论,导出了层状球体大地条件下长周期大地电磁响应的计算公式,编制了计算机程序,并对相应理论模型进行正演计算。根据计算结果,分析了地球曲率对长周期大地电磁测深法视电阻率和阻抗相位的影响。理论模型的计算结果显示,随着探测周期的增大,地球曲率对长周期大地电磁响应的影响逐渐增大,视电阻率曲线会明显下降,阻抗相位曲线逐渐趋于90°;在一维情况下,对于目前的仪器测量范围可以忽略地球曲率带来的影响,但随着仪器技术的进一步发展,地球曲率对长周期大地电磁测深法的影响不可忽视。
Based on the electromagnetic theory,the forward formula is obtained for the longperiod magneto telluric（LMT） method in a layered spherical earth. The computer program for computing the LMT re sponse is worked out and the forward modeling is completed for some theoretical models. According to the results of forward modeling, we analyzed how the earth＇s curvature influences the electromagnetic response. The results show that the apparent resistivity will decline and the phase will increase with an increased probing depth. However, the impact of the Earth＇s curvature can be ignored in the case of onedimensional base regarding the measurement accuracy of the LMT instrument at present; But with the development of instrument, it is necessary to take the earth＇s curvature into account in the fu ture.
出处
《地震地质》
EI
CSCD
北大核心
2012年第3期456-466,共11页
Seismology and Geology
基金
国家自然科学基金(40839909)"扬子西缘深部结构与油气赋存背景研究"和"深部探测技术与实验研究专项"(201011043-02)资助
关键词
长周期大地电磁测深法
电磁响应
层状球体模型
地球曲率
视电阻率
阻抗相位
long-period magnetotellurics （ LMT）, electromagnetic response, layered spherical earthmodel, the earth＇s curvature, apparent resistivity, impedance phase
