The Choice Of Parameters In The Correspondence Analysis Method Of Gravitational And Magnetic Anomalies And The Application In The Real Data Processing In Dongbei Region

Set out from Poisson's theorem, this paper introduced the method ofcorrespondence analysis of gravitational and magnetic anomalies andsummarized its history and existing state. For the purpose of enhancing thedata reliability, it designed the theories model of the three-dimensionalbody-sphere and the planar body-step, studied the related coefficient R,slope B and intercepts A of model's gravitational and magnetic abnormalityand searched for the optimal dot and line spacing, analyzed the effectbrought by the window and residual magnetization orientation oncalculation result after carrying on the process of correspondence analysisof gravitational and magnetic anomalies.For the sphere theories model, it has been certified by a vast calculationon the different dot and line spacing and the different window radius, thatthe suitable window radius was about 1.5 times of model radius and theresult was not easily affected by the density of dot and line spacing. Toestimate the effect of residual magnetism on the result, design residualmagnetic bias angle equal to geomagnetic field bias angle, residualmagnetic obliquity changed from -90° to 90°, the result indicated that if thebias angle between residual magnetic orientation and geomagnetic fieldorientation changed from-15° to +15°, parameters obtained were steady. Atthe same time, we obtained the effect on the result when the bias anglebetween residual magnetic obliquity and geomagnetic field obliquity, andconcluded the fact that in the case of bias angle ranged from -15° to +15°,parameters obtained were steady.For the perpendicular step theories model, designing also the differentdot and line spacing and the different window radius, carried on thecorrespondence analysis of gravitational and magnetic anomalies. Theauthor concluded that the it is better for the result of correspondenceanalysis that line spacing are 200m and the window radius choose is or so1.2—1.8 times of model ply. To estimate the effect of residual magnetismon the result, design residual magnetic bias angle equal to geomagneticfield bias angle, residual magnetic obliquity changed from -90° to 90°, theresult indicated that if the bias angle between residual magnetic orientationand geomagnetic field orientation changed from-15° to +15°, parametersobtained were steady. At the same time, we obtained the effect on theresult when the bias angle between residual magnetic obliquity andgeomagnetic field obliquity, and concluded the fact that in the case of biasangle ranged from -5° to +5°, parameters obtained were steady.Making use of the conclusion obtained from the examination of theorymodel;Make the processing of the method of correspondence analysis ofgravitational and magnetic anomalies to 1:1,000,000 actual data inDongbei region. after the linear analysis of the aeromagnetic anomalydisposed and one rank vertical derivative of gravitation field, the value ofthe approximate straight line calculated is about 0.It certificated that therock density and magnetism in the area satisfies with the basic condition ofPoisson's theorem Then choosing the 50km′50km window radius, carryingon the correspondence analysis, its results concluded that the strongmagnetic rock has stronger surplus magnetism, and certained the distributescope of strong magnetism and surplus magnetism from the inclined rate Band intercepts A of model's gravitational and magnetic abnormality instudying region. It provided the good foundation Geophysics data for theinvestigation and evaluation of the strategic district of oil and gas in china.