A Technique Of Argumentation About The Application Of Local Wavenumber In Magnetic Interpretation

The two-dimension local wavenumber method has been definitely used to inverse boundary position and burial depth of top boundary of the magnetic substance. The advantage of this method is that it doesn't go along with the magnetization and tip, and the disadvantage is that it is only fit for particular source models, such as slopping fault model, dipping thin sheet model and horizontal model. Some computational techniques of numerical value will directly affect the accuracy of the inversion resultant during the inversion.The original is based on the research of predecessors, and talks about some means and techniques of the local wavenumber inversion. Firstly, how to choose extension method of frequency domain processing: by means of comparing cosine function extending edge and minimum curvature extending edge, we think minimum curvature extending edge is superior to cosine function extending edge. Secondly, there will be affection of enhanced high frequency while we calculate the higher derivative of magnetic anomaly, for the sake of overcoming the affection, we propose a method which up-continues some altitude to calculate higher derivative or local wavenumber, and this method not only resolves the problem of enhanced high frequency, but also resolves the problem of how to choose the parameters of low pass filter. We use Fortran 90 to program the homologous programs, and try to calculate the affection of different burial depth, section length, dot pitch and magnetic intensity to the inversion of the same model. Then we try to calculate the affection of the three particular models which don't meet the condition of the two-dimension local wavenumber method. Finally, we use the northern airborne magnetic data of South China Sea and inverse the burial depth of the anomalous body; also we obtain comparatively satisfactory result.