The Study Of Differential Coefficient Imaging Of Apparant Vertical Conductance In Transient Electromagnetic Method

The TEM(Transient Electromagnetic Method) is a kind of exploration method that takes use of the measuring abnormity to analyze the conductive capacity and the position of the underground non-homogeneous substance to resolve the geology problems.However,using the apparent vertical conductance conversion imaging to search for low resistance layer is more visually than the traditional apparent resistance method in the layer earth electricity section model.It is because that according to the electromagnetic theory,the underground uniform medium can be replaced by an electric plane,then it is conveniently to seek the changing inductive electromagnetic field with time 't' in any space point by mirror imaging method.The electric plane flow up and down at the speed of 1/μ₀σ.This can alter the swing and phase in random space point.With time changing,transient electromagnetic field spread to the deep stratum.If there occurs a mew electric layer,the total vertical conductance value increases.In order to emphasize the change of the total vertical conductance with depth,we have differential imaging to the vertical conductance to make the layer character more obviously.This is the reason that the vertical conductance curve is more vividly to determine the existence of the electric layer than the apparent resistance curve.In this article,we introduce a method of taking use of the apparent vertical conductance differential imaging to do the qualitative and quantitative interpretation at interpretation of TEM.After the elaboration for the principle of the differential imaging,this paper show the advantages of using apparent vertical conductance differential imaging to do the date processing and interpretation of transient electromagnetic sounding.At the same time,in order to resolve the problem that because the wrong(?) after the inversion, affecting the interpretation's termite solution of apparent vertical conductance S_Ï„and apparent depth H_Ï„,and the large differential of imaging of inversion and true target.We use genetic algorithm to require the optimization(?).And still,we do some improvement in the program to resolve the optimization(?).In order to increase the resolution of electric undersurfaces,basing on the confirming the meaning of apparent vertical conductance and its' physical meaning,we may use cubic spline interpolate to do data processing, and achieve the imaging of parameter of conductance.Apparent vertical conductance differential imaging can coincide with other ways,and its' "electrical phase axis" shows the form of range of electrical boundary surface lucidly with intuition.