In terms of collecting fracture data on an outcrop, the scanline method is one of the common procedures ( Priest and Hudson, 1981 Mauldon et al., 2001). Generating georeferenced outcrop models using a drone has been proven to help geological mapping in dolomite ( Madjid et al., 2018), sedimentology research ( Westoby et al., 2015), and observing gas plumes of a volcano ( Jordan, 2015) among many other researches on bringing outcrops into the digital world. Eventually, methods of fracture identification using DSM are expected to be capable as options in preliminary fracture data collecting on outcrops, especially when the scanline is unable to be performed.ĭigital Surface Models (DSMs), or also known as three-dimensional outcrop models/digital outcrop models, have played many important roles in geoscience research. The differences rely on several conditions, such as the geometry and texture of the outcrops. The results show that the semiautomatic measurement using RGB-filtering texture has the closest pattern to the scanline data compared to the hill-shaded DSM method. The textures of DSMs are also used in fracture identification through RGB filtering as the third method. The images are then processed into hill-shaded DSMs to be automatically analyzed following the algorithm in PCI Geomatics software and manually assessed.
Structure-from-Motion (SfM) photogrammetry is utilized to generate the DSMs, where a series of aerial images are captured using Unmanned Aerial Vehicle (UAV). Two well-exposed granite outcrops in Bangka, Indonesia, are designed for the pilot area. The second method is applying fully automatic and manual fracture identification by optimizing hill-shaded DSMs.
The first method applied in this study is the scanline method to collect fracture data directly from outcrops, measuring more than 1,400 fracture data. This paper reports the DSM robustness by comparing the result of fracture-lineament measurement using DSMs and discusses the possible causes of error that might occur. Along with the advantage in the rapid acquisition, DSMs are capable of creating virtual models of fractured outcrops to be interpreted for further analysis.
Three-dimensional outcrop models, or Digital Surface Models (DSMs), have proved their capacity in many geoscience studies.
0 kommentar(er)
