TN887 : 3D Inversion Modeling and Joint Interpretation of Gravity and Magnetic data in the region of Bazman
Thesis > Central Library of Shahrood University > Mining, Petroleum & Geophysics Engineering > MSc > 2019
Authors:
Sara Nasri [Author], Ali Nejati Kalateh[Supervisor], Amin Roshandel Kahoo[Supervisor], Mehrdad Soleimani Monfared[Advisor]
Abstarct: Geophysical methods are known as appropriate methods for prospecting and exploration of mineral deposits. These methods, if properly selected, provide valuable data on reconnaissance of subsurface mineralization. Conventionally, 3D modeling have to be performed to identify geometrical properties of subsurface structures such as shape, depth, width, and depth of the center point. It should be noted that each geophysical method is appropriate for a specific type of mineralization and therefore should be accompanied by other methods for comprehensive interpretation. Therefore, it is required to apply methods with advantage of simultaneous interpretation, which requires a logical relationship between the model quantities. Therefore, here two strategies were introduced. In one strategy, the inverse modeling is attempted, and in the other strategy, it is tried to integrate results of the inverse modeling of each method with each other. In the presented study, the later mentioned strategy was used to simultaneously interpret results of three-dimensional of gravity and magnetic models. In the presented strategy, the 3D discrete wavelet transform (3D-DWT) was used as an efficient tool for data integration. This method has the ability to simulate the models. Therefore, we first normalized the models of magnetic and gravity in the field of transformation. Then, using 3D-DWT, two types of components were created on the models. The first three parts of these components relates to the details of the model and the second component relates to the approximation information contained in the data. To fuse those components, a weighting algorithm with a special properties for details were used. The fusion procedure in this strategy took place at three levels. Afterwards, by applying the inverse discrete wavelet transform (3D-IDWT), all of the components mentioned gave rise to final integration of the gravity and magnetic. The technique was then applied on two synthetic models with Gaussian noises of 2% and 5%, respectively. After applying the strategy on a synthetic model, the method was applied on real data. The real data is related to a region in southeastern Iran in Sistan and Baluchestan province called the Bazman, which has a direct relationship with moving the subduction zone of the Makran. The data used in this study is airborne magnetic and satellite gravity measurements. When results of the inverse modeling of each data were combined, thus they could be interpreted simultaneously. For evaluation of results, available geological evidences were used. According to the results of fusion main anomalies with high deep expansion were located in the northwest of the area. Two other anomalies also were located in the center and south-east of the area, which has a lower deep expansion than the other mass. It should be mention that fusion of models and the inverse model are both in accordance with the data.
Keywords:
#3D inverse modeling #Fusion of potential field data #Interpretation of airborne Data #Gravity and Magnetic modeling #Li- Oldenburg #Bazman #Sistan and Baluchestan Link
Keeping place: Central Library of Shahrood University
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