The Study And Application Of Potential Fidld Data Processing And Interpretation Based On Multiscale Derivative Analysis

The potential field can be seen as superposition of gravity and magnetic effects caused bythe field source body of different scales and spread. One of the main tasks of the processingand interpretation of field data is separating the complex and interferential gravity andmagnetic effects of field source body, and than making geological interpretation to potentialfield effect of different scales field source body.There are some conventional methods of separating potential field, such as windowmethod, the sliding trend analysis, analytic continuation method, regularization of the filteringmethod, forward peeling method etc. These methods are based on certain mathematicaltheories and are built usually under the ideal and hypothetical principle. The separating thepotential field using these methods often leads a lot of distortion, which is cause by thedifference of actual situation and the ideal hypothetical principle.Typically, geological boundaries are decided by mark of linear gradient zone, rulesdistorted, horizontal dislocation etc. of gravity and magnetic anomalies. However these marksoften can not be clearly manifested, because the differences in geological structure andcharacteristics, evolutionary history, geological and geophysical conditions etc. Therefore,inaddition to features of the gravity and magnetic anomalies plane contour, we should alsoconsider features of switching field of gravity and magnetic anomalies, such as high-orderderivative, directionalderivative, convolution filtering, analytic continuation etc. However,compared with actual position, the boundarys of field source body estimated by these methodshave system offsets. Under the circumstance of not separating the potential field, the boundaryinformations of different scales field source body are displayed in the same map.MDA(Multiscale derivative analysis) bases on EHD(enhanced horizontal derivative),andcombines separating the potential field by vertical derivative and deciding boundary by totalhorizontal derivative. MDA decides boundary of different scales field source body by selectingthe appropriate parameters. Compared with the conventional methods of seperating field dataand deciding boundary of field source body, MDA avoids the distortion and containscompletely the anomaly information, because it doesn’t seperate the field rigidly and onlyrelatively enhances effect of field source body with corresponding selected parameters and rapid point boundary of field source body.This paper designs the single geological model and the combined geological body modelbased on the theories related MDA. The paper analysises the stability of ISVD algorithmwhich are used to calculate the each order vertical derivative of potential field, the effective ofseparating potential field by high order vertical derivative and influence of differentparameters to MDA. At the same time, the paper rely on the project of ‘The research report ofintegrated gravity acquisition, processing&interpretation services, Block L2of LAMU Basinin Kenya’. The paper processes the gravity anomaly data of block L2of LAMU basin inKenya, identifies different scales linear structure of study area and infers fault system of studyarea through combining with other geological and geophysical material. MDA can separatepotential field data and identify boundary of different scales field source body effectively.