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Spatial domain topological processing technique for studying static effect in magnetotelluric sounding |
Gui-Mei LIU( ), Wei MA, Jun-Chang LIU, Xin-Xue XU, Guo-Lei ZHENG, Zheng LIU |
Geophysical Prospecting Center of Tianjin, Tianjin 300170, China |
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Abstract The static effect is a commonly-existent technical problem in MT method, and its influence could lead to an unacceptable result of the observation data. According to the distinguishing method, correction method and the data collection system, the authors put forward a spatial-domain topological processing method based on the original data. Through the analysis of the cause and representation of the static effect and the superposition characteristics of electric field components, the authors began with the essence of space sampling and completed the formula for obtaining the topological curve, finally got the observation result with different pole distances at the same site and found out the implicit observation information in the observation system of continuous arrays. According to the analytical result of theoretical model, the authors established the model of all the possible static migrations of the record site with the change of pole distance in different parts of local inhomogeneous body and, in addition, established the basic topological result graphic display and interpretation method including using sites to do pseudo-section processing and using the fixed frequency result of all sites in a profile painting pseudo-planar graph. The authors also compiled the software of topological processing and finished this new method of using topological processing method to analyze the static effect of MT both in theory and in application. The test result proves that the topological processing could improve the quality of data. With this technique, the discrimination of static effect could begin with many aspects, could find out the spatial distribution of the distorted electrical field caused by local inhomogeneous body, and could find out the location and spatial distribution of the local inhomogeneous body, thus providing researchers with real information on the surface electric structure. The topological processing could also get the result of changing arrays, and this means the emerging of a new method for inhibiting interference.
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Received: 18 April 2017
Published: 20 February 2018
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