Study On Inversion Method Of Field Source Distribution Based On Combination Of Different Order Derivatives Of Gravity And Magnetic Data

Based on the fractal correspondence between the different order derivatives of field source and anomaly of gravity and magnetic.we have developed a field source distribution inversion method based on the different gradients of gravity and magnetic anomaly,focusing on achieving high precision and high resolution inversion of the field source edge and depth,so as to obtain accurate geological body distribution..(1)To address the problem of the low resolution of existing edge detection methods,we analyze the relationship between different order derivatives eigenvalues and the field source edge,and develop a edge detection method with different order derivatives ratio.Model experiments demonstrate that this boundary recognition filter has a higher horizontal resolution and can give more accurate boundaries of the geologic body compared to a conventional equalized boundary recognition filter with the same gradient ratio.Model tests show that this edge detection filter has higher horizontal resolution than the conventional equalization edge detection filter with the same order derivatives ratio,and the edge of geological body can be showed more accurately.Since it needn't calculate the vertical derivative,it has good noise resistance,which is conducive to anomalies interpretation.More detailed information can be obtained from the edge detection with ratio for different order derivatives,and geological structure interpretation can be realized more conveniently,and there is nice application value in geological survey.(2)The linear corresponding equations between the ratios for different order derivatives and the positions of field source are derived,and the edge detection results with high resolution of ratios for different order derivatives are used as the screening conditions,so as to obtain more convergent and accurate inversion results.Model tests show that the calculated results of the field source location information are in goodagreement with the experimental results.The result of the calculation is consistent with the actual position,which has a good ability to resist noise interference.(3)In view of the rapid access to geological position,imaging technology for different order derivatives in a space is put forward,through formula derivation,it's known that when the source depth is 0,eigenvalues of different order derivatives intersects in the actual location of geologic body,therefore,imaging method for eigenvalue intersecting points for different order derivatives is put forward,intersecting points of different order derivatives are found to obtain accurate position of geologic body.Through the theoretical model test,it is proved that the imaging method with intersecting point of different order derivatives can obtain the depth information of geological body quickly and accurately,and no interference anomaly will occur,and it has high noise resistance.This method does not require complex operation,the depth of geological body can be obtained directly with the extreme point,which has a convenient application in actual data interpretation.In this paper,the above three methods are applied to the gravity and magnetic data in Xihu sag of East China Sea Shelf Basin,and the edge detection results are obtained by using the edge detection method with different order derivatives ratio.on this basis,actual position of the edge is obtained by using the imaging method with intersecting points of different order derivatives,In order to avoid the result error caused by single method,the field source linear inversion method based on phase step edge detection method is used to obtain the final edge detection result,so as to explain structure distribution in Xihu sag.In this paper,three kinds of high-resolution inversion methods of the field source location distribution are proposed by using the corresponding relationship between the gravity and magnetic gradient and the field source location,which are used to obtain the field source location distribution information,improve the accuracy of the inversion results,and have good application prospects.In this paper,the method is combined with the gravity data of Xihu sag in the East China Sea shelf basin to realize the structural division of Xihu sag and correct the eastern boundary of the sag.