Research In The Method Of Extracting Gravity And Magnetic Local Anomalies And The Application

As an important method，Gravity and magnetic geophysical exploration has beenwidely applied to actual production. The extraction of Local Gravity and MagneticAnomalies is one of the important aspects of data processing, which is also theprerequisite of inversion and interpretation. In the actual production, we collectedgravity and magnetic data, which used to superimposes various geological anomalyfactor, which is a comprehensive reflection of different sizes and depths of geologicalbody, and contains a lot of information. Information extracted from such a complexwe are interested in the local rock (ore) caused by abnormal body, then its relevantgeological study and solve problems of great practical value. Over the years, manypeople have done so much research, but failed to get a good solution to this problem.In this paper, the author conducted the study on the circumference of themethods, the mean-field method, cutting method and trend analysis of four theoreticalmethod to extract local gravity and magnetic anomaly method. Through a multi-sphere models, the sphere-cylinder model levels and spheres-affect the verticalplate-like body three types of model test model, the depth of field of the source body,the position and shape of the abnormal separation and extraction of four methods;circumference method, the average field method and to determine the optimal radiuscutting method; affect different orders abnormal trend analysis extracted; through alarge number of maps and statistics on the results of four methods to extract the effectof local anomalies were compared and analyzed, to find different ways to applyconditions and the advantages and disadvantages.In practical applications, the author take Tibet gravity and magnetic data andSichuan gravity data as examples, according to the characteristics of the actual data,the radius of the different methods to determine the best or optimal order times. Theauthor took circumference method, the mean-field method, cutting method, trendanalysis method to extract the partial exception and for comparison. Through thepractical application of the analysis of four methods to verify the advantages and disadvantages of different methods and conditions, showing the circumferencemethod, partial anomalous good results and good prospects mean field method andcutting method, noting that the trend analysis limitations in the application of the law.