Study On The Theory And Application Of Air Electric Field Magneto-telluric Method

In recent years,with the rapid growth of China ’s demand for underground mineral resources and the maturity of shallow geological exploration technology,mineral exploration has shifted from the past in the east,shallow,terrestrial,and structural mineral deposits to the west,deep,marine,and strata.Mineral change.With the increase of the burial depth of the exploration target,the geological environment and structure have become more complicated,and the difficulty of detection has also increased sharply.Therefore,there is an urgent need for a non-contact measurement method that is fast and sensitive to geological information.Since the non-contact measurement method was proposed,it has received widespread attention from scholars at home and abroad.Based on previous studies,some scholars have proposed the Air electric field Magneto-Telluric method(AEMT).Compared with the traditional electromagnetic method,this method has the characteristics of no electrode deployment,high working efficiency,and can be used for engineering surveys in exposed bedrock areas and urban complex terrain areas.In this paper,the vertical electric field component of the surface air,the source of the Air electric field Magneto-Telluric method,is introduced.The analytical formula of the vertical electric field in the surface air is listed and solved.The influence of the ground surface on the radiation pattern of the vertical electric dipole is analyzed.Based on the Magneto-Telluric theory,this paper puts forward the Air electric field Magneto-Telluric method,introduces its measuring principle,makes different capacitive electric field sensors,verifies its ability to measure the electric field induced by underground geological bodies,and analyzes the factors affecting the performance of capacitive electric field sensors.According to the principle of Air electric field Magneto-Telluric method,the apparent resistivity measured by it is defined,and the apparent resistivity curves of different formation models are analyzed.Finally,through the pipeline simulation experiments,very low frequency response acquisition is performed to verify the feasibility of the vertical electric field detection by the Air electric field Magneto-Telluric method;the campus hill simulation experiments provide experience for field surveys.Finally,field data collection was carried out in a tailings pond in Shangrao,Jiangxi.The least square method inversion method based on active equilibrium constraints was used to perform two-dimensional inversion of the Air electric field MagnetoTelluric method and AMT measured data.The verification shows that the method can reflect the masking conditions of underground mines and is more practical.