The Improvement Of The Gravity Gradient Method Determine The Parameters Of The Subsurface Structure Body

I came into contact with the gravity gradient method since2007, and made athorough research. Beginning, the author in order to reduce the gravity gradientmethod for solving multi-solvability, the first gravity bit unusual vertical secondderivative and horizontal derivative, to determine the location of the fault zone withinlarge area, for the gravity gradient method to create a suitable computing interval.Then use the gravity gradient method to calculate the subsurface structure within itssmall area. Although this joint solving a certain extent, inhibited the wrong result, butdoes not consider the gravity anomalies in the derivation process to produce highfrequency amplification error for accurate solving the location of the undergroundstructure of the body is not very good results;, the accuracy of the interpretation oftheresults is further reduced; and the method used in the calculation of the small regionaltilt stairs, some defects in the calculation of the vertical steps and a large area.Provide a good basis for improved methods can effectively remove some errors,vague information to explain, for carrying out the actual data processing dataprocessing in an unknown region to make a good inference, pave the way for othermethods of explanation.To solve the above problems, the author again on the gravity gradient method hasbeen improved.For one, the introductions of the smoothing filter do B.MThe conventional derivation in order to weaken the error impact, generallysmooth handling, or taken before the calculation and the calculation of the filter andother measures to eliminate the results of the derivation. But underground there areother geological bodies, then you can not use the above methods to weaken the impactof good, to solving Vzz and Vzx will cause a greater impact.. In this paper, thederivation process to add the factor of the wave number domain filtering method, andselect the relevant parameters, in building a diagram of the spatial parameters cangreatly weaken the impact of the various geological bodies. While the introduction ofthe filter factors can also increase the stability of the calculation. In computerprogramming, and enable the parameters to select the more convenient and flexible.Reasonable choice in the actual processing of the index n and harmonic numberN of the Legs in filter factor, reduces the impact of interference sources; the accuracy requirements of the gravity gradient method has a great relationship with the scale ofthe data, the scale is too small, it will cause many small strait graphic division is notout in the stratum divided, we should try to select a large scale, the actual dataprocessing, but also the size of the scale, a reasonable choice for the density profileline;Second, the introduction of the state discriminating factorsHowever, due to the high requirements of the gravity gradient method on theaccuracy in the data quality is not high or difficult terrain, gravity gradient method todetermine the right angle position results will appear Multiplicity of Solutions for anill-posed problems. Solving ill-posed problems in the past, usually magnetic, electrical,seismic and other data to explain the results of the constraints of gravity.However,this constraint is often the following three questions: First, timely informationfeedback, the constraints reduce the effect of gravity gradient method;the introductionof various constraints to the logical judgment is more complex, leading to theinterpretation process more confusing; is the application of large amounts of data,resulting in increased workload. In order to solve such draw backs and to moreaccurately determine the location of the corner, this paper introduces the statediscriminating factors to be optimized to determine the location of the corner. Thecalculation results show that this method is more accurate than the routine todetermine the angular position. The method can to some extent, evidence to thecontrary conclusion, namely: use of the location of the corner back steppingstatediscrimination factor f, if the range of values of f and f in the same interval, and thedifference between the two size does not exceed5%of the value of f, prove the resultsare correct, otherwise the error in the solution process.Different from previous authentication method of contrast electric and magneticresults, the introduction of the state discriminating factors, the whole work does notrequire carrying out the overall verification After explaining the end of a section, andif the interpretation process, if there are problems, it can be modified at any time,reducing the amount of computation, to reduce logic errors. Practice has proved thatthe state discrimination factor (f) after the introduction of the gravity gradientmethod,the calculation accuracy has been greatly improved, and in the calculationprocess can be combined with feedback information (inclination and depth), easy toremove the wrong solution. In accordance with the relevant magnetic, seismic,electrical data on the location and occurrence of the underground ore body todetermine.This theoretical proof, the improved method used in Inner Mongolia Tao Langand Doug region. And a variety of geophysical methods in the study area calculatedtoget the results of the gravity gradient method, the results obtained do should andintegration. (1) Horizontal derivative and vertical derivative of the study area is divided toconstruct large regional Mainland boundary and fracture, provided thepremise for the gravity gradient method in the small area. While takingadvantage of the obtained results do verify the results obtained by the gravitygradient method. The high degree of similarity, then the result is correct, ifthe degree of similarity is very small, or the opposite results, will have on thearea of the error, re-calculation. General this problem, there are two kinds ofa subsurface structure of the error region into a variety of geological bodies,if this is the case, you might consider the interpretation of the results of theimproved gravity gradient method; the case is the error area is a simpleconstruct, but because of the presence of near depression or cave, so that theconstructor body of a variety of interpretation of the results, if this happens,you need to reference the results of other methods for the integratedtreatment.(2) The combination of the Euler disconsolation and apparent density inversionand wavelet multiresolution analysis method to infer the location anddistribution of homebodies in the district. Inversion of apparent density canbe roughly delineated the distribution of ore bodies, in contrast gravitygradient method, the location of the underground structure, withcorresponding effects; fracture and tectonic boundary, the gravity gradientmethod can effectively complement the Eulerdeconvolutionanti-performances; wavelet multiresolution analysis can bemade of the gravity anomaly area, gravity anomaly area is the location of theunderground structure of the body by observing the wavelet multiresolutionanalysis of the results can verify the gravity gradient method to get results.(3) the study area is mainly metal ore bodies, factor in this article also do theelectrical method of data processing, and collected the drilling data, theinterpretation of the results of the knot and drilling data and power law canroughly infer that the main ore body of the study area chalcopyrite, pyrite andassociated witha small amount of tungsten ore.3D interpretation map of theunderground structure of the body by gravity gradient method, can be seen inthe study area in central, north and south; a North East to the subsurfacegeology throughout the study area, study area is divided into three parts: theNorthwest central, and southeast; northwest with the geological bodyintersection of uplift, combined with information on this power law can bejudged that the area is a metal mining area; the southeast there is a z-shapedgeologic bodies with the same You can get this z geological body is the areaof the ore body is mainly concentrated.(4) In order to verify the gravity gradient method is accurate or not, selected fourprofiles in the study area, its done processing, and results compared to the results obtained with the area of the earthquake, but also the use of the pastthe results obtained by the gravity gradient method, by contrast, experimentalresults show that the physical parameters of the introduction of statediscrimination and filtering factors, to more effectively determine thesubsurface structure body.The gravity gradient method to extend the type of geological structure oftruncated board and the local fracture as a better interpretation of results-basedapproach, and it does not need to be estimated in advance and given the density of thesubsurface geology. Therefore, in theory and in practice has very importantsignificance. In theory, it can be a good complement existing methods ofinterpretation of the fracture construct a more powerful theoretical explanation modelfor gravity exploration; to fundamentally improve the practice, now some of theunderground structure of the body interpretation accuracy, distinguish it from the hugecost of the earthquake and other methods, it is low cost, and the gravity gradientmethod has a good theoretical significance and enormous social and economicbenefits.