科研之友
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摘要
With the ongoing development of the full potential field gradient techniques, more and more gradient tensor data have been widely used in geophysical exploration for its large amount of information and containing higher frequency signals than potential field data. The full potential field gradient technique can simultaneously measure six gradient components. Each component has its own geophysical meaning. The high frequency gradient tensor data can be used to delineate small scale anomalies. @@@ Edge detection is required for interpretation of potential field data, and has been used in exploration technology for discovery of mineral resources. The main geological edges are fault lines and the borders of geological or rock bodies of different density, magnetic nature, etc. On account of the higher-frequency signals, their interpretation enables high-resolution and detailed investigation of geological structures. Development of new methods is required to enable interpretation of these data, especially for edge detection for small geological structures. @@@ In order to make use of multiple component information, we define directional total horizontal derivatives and enhanced directional total horizontal derivatives and use them to define new edge detectors. However, the new defined edge detectors can balance the detected edge signals of different amplitude anomalies. In order to balance the edge signal amplitude, we present a normalization method, where we divide the new edge detectors by the vertical potential field gradient data. Besides, we introduce a constant parameter in the denominator of the normalization method, which can effectively avoid bringing some additional false edges when real geological bodies contain positive and negative anomalies simultaneously. @@@ These methods have been tested with synthetic data to verify that the new methods can delineate the edges of different amplitude anomalies clearly. The results show that new defined directional total horizontal derivatives and enhanced directional total horizontal derivatives have higher resolution than directional analytic signal. The normalized edge detectors can display the edges of large and small amplitude anomalies simultaneously, and avoid introducing additional false edges. To further test the stability, we demonstrate the new edge detectors with the model data corrupted with 5% Gaussian noise, Finally, we apply these methods to real full gravity gradient tensor data in St. Georges Bay, Canada and magnetic anomalies in Zhurihe area, China, and get good edge results.
- 出版日期2015-7
- 单位国家海洋局第二海洋研究所; 吉林大学
