Total horizontal derivatives of potential field three-dimensional structure tensor and their application to detect source edges

Abstract

Edge detection of the geological structures horizontal position is the vital task of the potential field interpretation, and some traditional edge detectors have poor ability in delineating edges clearly and accurately. Some people made efforts to purpose new methods which can balance the weak and strong anomalies simultaneously. In this paper, we purposed new edge detection methods based on directional total horizontal derivatives of three-dimensional structure tensor for the causative sources. In order to balance weak and strong amplitude anomalies simultaneously, we used the vertical derivatives of potential field to normalize the new defined filters. For the complex geological situation with positive and negative gravity or magnetic anomalies, we introduced a new strategy to reduce the false edges. The presented filters were tested on synthetic and real potential field data to verify its feasibility. All of the results have shown the new edge detection methods can not only display the sources edges precisely and clearly, but also bring out more geological subtle details.

Comparison of different approaches of computing the tilt angle of the total horizontal gradient and tilt angle of the analytic signal amplitude for detecting source edges

“…Figure 7f displays geological map of the area (modified from Ma et al, 2014). The continental sediments cover most of the Zhurihe area, except for some nearly SE -NW trending iron-rich sandstone dykes (Ma et al, 2014, Zhou et al, 2017. As can be observed, the edge maps of the TTHG are consistent with the geology information (Figure 7f).…”

Structural Study of the Kakobola Area and Its Surroundings by Detecting the Edges of Gravity Anomaly Sources

“…As the FTDHT is calculated from the second derivatives, noise is ubiquitous in FTHDT results (Zhou et al, 2017). However, the examination of the FHDT and TA shows that Kakobola and Gungu are indeed located on sites of low or medium anomalies.…”

“…First-order total horizontal derivative (FTHDT) method FTHDT is the square root of the squares' sum of first-order directional total horizontal derivatives along the x and y directions of an original potential field (Zhou et al, 2017). The first-order horizontal directional derivatives along the x and y directions of the horizontal derivative of TDR are given by the following respective relations (Zhou et al, 2017):…”

“…The FTHDT method is used to highlight the edges of geologic structures, which can be faults, fractures, geologic contacts and fold axes. The dips θ of the edges of geological structures are then given by the following relationship (Zhou et al, 2017):…”

Edge detection for the buried archaeological structures with the geophysical image processing method in the Alabanda Ancient Cistern in Turkey

“…In parallel with these developments, the use of MGTs in edge detection studies from magnetic data has increased considerably (e.g. Oruç, 2010;Wu, Li, Xing, & Zhang, 2017;Yuan & Yu, 2015;Zhou, Huang, & Jiao, 2017). In recent years, eigenvalue analysis of the gradient tensor has been widely used to describe the edge and lineament characteristics of buried sources.…”