Improved Tilt Derivative And Gravity Inverse Research Of BP Neural Network

The distribution feature of the geophysical field is correspond in the syntheticrespondence of underground various geological body. Make use of the large volumes of regional potential field data, ascertaining the relation of the geological body and potential field is one of the main contents of the geophysical potential field theoris. Usually the depth to top edge, the location of its edges and physical properties parameters of the source causing the anomaly are the problems that we concern most.In recent years, our country carried on the extensively regional gravity , ground-magnetic and aeromagnetic surveys, acquiring a great deal of gravity and magnetic data with high precision and high resolution, the data almost overlaid a majority of national territory. Therefore make use of these data well and availably, withdrawing the geology information morely, further improving the interpretation's veracity and precisions, have important realistic meaning.The gravity and magnetic survey take the physical properties( density, magnetism)difference of the geological body as the foundation, reflecting the physical properties distribution feature of the geological body unusually, we can determinate or estimate various physical properties parameter of the geological body on these grounds. From the angle of the potential field information, revealing the regional geology body information by various means, is a potential data processing technology's general guiding thought. In various processing technology, the derivative play an important role, it can help certain or estimate the shape, location of its edges, depth to top edge, susceptibility contrast of the source causing the anomaly etc..The total magnetic intensity anomaly corresponds distribution feature of the underground magnetic source causing the anomaly, determinating the location of its edges, depth to top edge of the source causing the anomaly etc. is main purpose of the inversion. Because actually geological body causingthe anomaly are what we can only study, in other words, only did the physical properties of the geological body vary in the special distribution, the anomaly of physical field can be caused. potential field's anomaly of surface of earth reflects the special distribution feature of the anomaly body( location of its edges, depth to top edge...etc.).So this thesis take withdrawing and identifying the special distribution feature of the source causing the anomaly as the emphases, determinating the location of the source's edges causing the anomaly especially.Since the potential field anomalies correspond to the superposetion of effcets from all causative sources. the stacking and interfering of the potential field are inevitable. while identifying and judging the location of its edges of the potential field source causing the anomaly, unusually according to the measured potential field of earth's surface is very difficult. But according to the property and characteristicses of the field in mathematics, people usually adopt the mathematical processing methods( such as continuation, making derivative. Etc.). separating the interference possibly, determinating the location of its edges of the source causing the anomaly.The text give priority to the technique of derivative, using the seismic complex trace processing technology, based on a great deal of job which the other people had done represents the conception of"Non-Absolute horizontal derivative of Tilt derivative". Solve the problem of the incline of the geologic bodies, systematically expound the method of Tile derivative, educe a series of problem and advice. Compare the method of Tilt derivative to general derivative, Tilt derivative can boost up the pick-up of more feebleness exceptional information, especially the exceptional information of the boundaries of the geologic bodies, Non-Absolute horizontal derivative of Tilt derivative besides boost up the pick-up of more feebleness exceptional information, we can also distill the incline of the geologic bodies by connectting the wave crest with trough. The text design the model of the Infinite extension steps,the model of the inclined block,the model of the Infinite extension andthe finite extension disk,the model of the faults and colligation models. By discussing of the five models, the method of Tilt derivative exists advantages that general derivative cannot surpass, but the method of Tilt derivative is also blank about the problem of critical values in or out. A certain extent the judgement of models also exist the interferential instance one another, the judgement of boundaries is restricted by the burying depth of the geologic bodies,the difference of density and thickness, all of the problems need farther argumentation and resolvement. To give emphasis that the text make use of finite extension disk designing colligation models, all of the burying depth and thickness of the geologic bodies make no difference the pick-up of the method of Tilt derivative, So the text puts forward that analyse irregularly geologic bodies into finite extension disk to explain.Inverse the abnormity of gravity and magnetic, should do data processing about field information of gravity and magnetic, in the process of inversion not only exist complex structure of geologic bodies areas that research, the information that obtained lead multiplicity of the results that inverse, but also in data processing of exists linear distribution of geologic bodies and non-linear distribution of geologic bodies, for different instance ,should make use of different disposal methods, the text make use of BP Neural Network mostly inversing linear geologic bodies, thereby research the burying depth and thickness of the geologic bodies, the text design the geologic model of steps and colligation to inverse used by BP Neural Network, because of the known of the information of boundaries and incline of the Tile derivative abnormity curvilinear, the quantity of information is reduced that needed by inverse, and in data processing inverse the boundaries and incline what information offered by the method of Tilt derivative, greatly reduce the multiplicity possible that brought by inverse.Make use of the method of general derivative and Tilt derivative figuring the abnormity with the gravity data of Lao's and aerogravity of northeast area, the method of Tilt derivative directly obtain relatively believable productionshow, it reject hash directly show the area of boundaries, give forceful evidence for compartmentalizing of the boundaries of geologic, otherwise, make use of the method of non-absolute horizontal derivative of Tilt derivative advanced in the text translating the incline of geologic, thereby estimate the structure of geologic. That has approved in the models, A certain extent because of the method of Tilt derivative also exist the interferential instance one another to estimate geologic, so some geologic structure need farther discuss. In the base of non-absolute horizontal derivative of Tilt derivative, make use of BP Neural Network researching one area of Lao's, Gauss coordinate of the area is abscissa Y=18472-18488km,ordinate X=1896-1902km, acquire perfect effect of inversing boundaries, inosculate the image of non-absolute horizontal derivative of Tilt derivative at this area, obtain favorable purpose.