摘要
针对大地电磁二维反演中TE、TM极化模式的选择问题,设计了多个二维、三维模型进行了正演计算,从数据对比和反演结果对比两方面入手,分析研究了三维模型和二维模型响应数据的差异、反演中极化模式的选择、以及三维模型数据的二维反演近似等问题.研究结果表明:在三维模型条件下,利用二维模型进行反演时,TE模式对模型的二维的近似程度要求远高于TM模式;当三维结构影响较明显时,利用TM模式数据进行二维反演比利用TE模式或利用TE+TM模式联合反演都更合理,反演结果中的虚假结构明显减少;对于TM模式,相位受三维畸变影响较小,视电阻率较大,所以二维反演中可适当加大相位的权;对于实测数据的二维反演,应优先考虑采用TM模式数据进行二维反演,其次是TM+TE模式,一般不要单独采用TE模式.
Aiming at the choice of data polarization mode in magnetotelluric 2D inversion, several 2D and 3D models are designed to study the difference between 3D response and 2D response, the choice of data polarization mode in 2D inversion, and 2D approximate interpretation of 3D data. The research is divided into two parts： one is the difference between 3D and 2D response, and the other is comparison of 2D inversion results. The results manifest that in the 3D scenario the demand for approximate 2D structure in TE mode is much stricter than in TM mode. When 3D effect is relatively severe, by applying 2D inversion to 3D data, the results show that the inversion model using only TM mode data is more valid, and the phantom structures are less than using TE mode or TE＋TM mode. In TM mode, the distortion of phase is less than apparent resistivity, so the weight of phase in inversion can be increased. For 2D inversion of field data, TM mode only is the first choice, next is TE＋TM, TE mode only is not proposed.
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2010年第11期2703-2714,共12页
Chinese Journal of Geophysics
基金
国家自然科学基金项目(40674036)
国家重点基础研究发展计划"973"项目(2004CB418402)
国家自然科学基金重点项目(40534023)
江苏省地震局青年基金项目(200901)联合资助
关键词
大地电磁
极化模式
三维模拟
二维反演
Magnetotelluric, Polarization mode, Three-dimensional modeling, Two-dimensionalinversion
