【摘要】 边界识别是位场(重磁)数据解释的重要内容,其对圈定异常范围,划分断裂构造等具有重大意义.Theta法是众多边界识别方法中一种应用较为广泛的方法,其为总水平导数与解析信号定义的比值函数.Theta的极大值对应着地质体的边界,具有能均衡不同埋深地质体边界的优势,但其受斜磁化的影响较为严重.全张量磁梯度数据具有高精度、高分辨率、多参量的优点,且其受斜磁化的影响较小,成为近年来位场数据处理与解释的研究热点.为了减少Theta法受斜磁化的影响,本文从Theta法的基本公式出发,推导出了由全张量磁梯度数据定义的新的Theta法表达式,本文称之为全张量磁梯度方向Theta法.通过模型试验,验证了全张量磁梯度方向Theta法的理论可行性,其边界识别的效果不仅十分清晰,而且受高纬度斜磁化情况下的影响较小.将该方法应用到大兴安岭北段某地区实测航磁数据的解释中,获得了异常体边界的大致分布.更多还原

【Abstract】 Edge detection is an important part of the interpretation of the potential field(gravity and magnetic) data,which is of great significance for delineating the anomaly range and dividing the fracture structure. The Theta method is a widely used method in many edge detection methods,which is a ratio function defined by the total horizontal derivative and the analytical signal. The maximum value of Theta corresponds to the boundary of the geological body,and has the advantage of balancing the boundaries of different buried depths,but it is more affected by the oblique magnetization. The full tensor magnetic gradient data has the advantages of high precision,high resolution and multi-parameters,and its influence by oblique magnetization is small,which has become a research hotspot of data processing and interpretation of potential field in recent years. In order to reduce the influence of the Theta method on the oblique magnetization,this paper derives the new Theta expression defined by the full tensor magnetic gradient data from the basic formula of Theta method. This paper is called the full tensor magnetic gradient direction Theta method. Through the model test,the theoretical feasibility of the full tensor magnetic gradient direction Theta method is verified. The effect of edge detection is not only clear,but also less affected by high latitude oblique magnetization. Applying the method to the interpretation of the measured aeromagnetic data in a certain area in the northern section of the Greater Khingan Mountains,the approximate distribution of the anomalous body boundaries is obtained.更多还原