AEMT Data Collection And Inversion

The basic principle of the Air Electric field Magneto-Telluric Method(AEMT)is to use a capacitive sensor to directly measure the alternating electric field in the surface air,a magnetic field sensor while observing an alternating magnetic field.The measured electric field value and magnetic field value were converted into apparent resistivity.Through the interpretation of apparent resistivity,the purpose of ascertaining the distribution characteristics of underground geological bodies was achieved.In this paper,the principle,characteristics and influencing factors of the capacitive sensor are studied,and a capacitive sensor is made to replace the traditional ground electrode.,The existing electromagnetic instrument EH4 was used for pipeline measurement at Donghua Square and Jinchang Square,and the manufactured sensor was tested,and its electric field induction characteristics were analyzed.The measurement error of the data was studied.The results show that the error can be controlled at 10% when superimposed a certain number of times.The AEMT data acquisition device is lightweight,avoiding errors such as inaccurate electrodes or inaccurate electrodes,improving data quality.The storage method and storage format of EH4 data were studied.The Y file reading,spectrum analysis and other programs were written in Matlab.The principle of Bostick inversion was introduced and an inversion program was written.The program conducted Bostick inversion of AEMT data collected at a spa practice base.The Bostick inversion method is not directly applicable to the inversion of AEMT data and requires phase correction.Introduced WinGlink data import,format conversion and inversion principles and processes.The nonlinear conjugate gradient method was used to invert the AEMT data of hot spring practice base.From the result,the data inversion map obtained by the capacitive sensor can reflect the underground geological structure well,and the horizontal orthogonal electric field was measured.In terms of data,this method of inversion is still applicable,and it also shows that the AEMT method is effective and feasible.