Field Verifications of Geological Structures Related to SAR Detected Lineaments

Abstract

Identifying geological structures is a crucial step in geological field mapping. One common technique to interpret geological structures is using lineament analyses on the satellite imagery. The usual encounters is many lineaments do not concordance to the geological structures. Overcoming the problem, we used dual orbit Synthetic Aperture Radar (SAR) images to obtain lineaments related to geological structures at ground level. In this paper, we presented the sensitivity of the lineaments detection method visually and automatically using Yamaguchi and modified Segment Tracing Algorithm (mSTA) methods, respectively. The Yamaguchi method is a visual lineament detection using an optimum image-scale and resolution. The method was used to detect lineaments based on visual limitation of the interpreter. On the contrary, the mSTA method is an automatic lineament detection utilizing SAR backscattering intensity images in opposite Line of Sight (LOS). Accordingly, we compared the effectiveness between the visual and automatic detection methods in detecting the faults and joints correctly at ground surface. The verification of detected lineaments at the field was then performed and analyzed to obtain comparison of the effectiveness between two lineaments detection methods. The direction of joints at EKA-01 were oblique 45 degrees to Yamaguchi method, and 25 degrees to mSTA method. Besides, the direction of faults and joints at EKA-10 were oblique 5 degrees to Yamaguchi method, and 2 degrees to mSTA method. mSTA method has smaller offset angle to field measurements than Yamaguchi method, indicating that the automatic is more effective and representative to detect lineaments related to geological structures than visual method.