Aditya Saputra, Trias Rahardianto, Christopher Gomez
Adequate knowledge of geological structure is an essential for most studies in geoscience, mineral exploration, geohazard and disaster management. The geological map is still one the datasets the most commonly used to obtain information about the geological structure such as fault, joint, fold, and unconformities, however in rural areas such as Central Java data is still sparse. Recent progress in data acquisition technologies and computing have increased the interest in how to capture the high-resolution geological data effectively and for a relatively low cost. Some methods such as Airborne Laser Scanning (ALS), Terrestrial Laser Scanning (TLS), and Unmanned Aerial Vehicles (UAVs) have been widely used to obtain this information, however, these methods need a significant investment in hardware, software, and time. Resolving some of those issues, the photogrammetric method structure from motion (SfM) is an image-based method, which can provide solutions equivalent to laser technologies for a relatively low-cost with minimal time, specialization and financial investment. Using SfM photogrammetry, it is possible to generate high resolution 3D images rock surfaces and outcrops, in order to improve the geological understanding of Indonesia. In the present contribution, it is shown that the information about fault and joint can be obtained at high-resolution and in a shorter time than with the conventional grid mapping and remotely sensed topographic surveying. The SfM method produces a point-cloud through image matching and computing. This task can be run with opensource or commercial image processing and 3D reconstruction software. As the point cloud has 3D information as well as RGB values, it allows for further analysis such as DEM extraction and image orthorectification processes. The present paper describes some examples of SfM to identify the fault in the outcrops and also highlight the future possibilities in terms of earthquake hazard assessment, based on fieldwork in the South of Yogyakarta City.
Geography Faculty, Universitas Muhammadiyah Surakarta; Geography Department, BUG Laboratory: Biogeomorphometry from UAV to Geocomputing, University of Canterbury, Private Bag 4800, Christchurch, 8041, New Zealand; Civil Engineering, Politeknik Negeri Malang; Geography Department, BUG Laboratory: Biogeomorphometry from UAV to Geocomputing, University of Canterbury, Private Bag 4800, Christchurch, 8041, New Zealand; Geography Department, BUG Laboratory: Biogeomorphometry from UAV to Geocomputing, University of Canterbury, Private Bag 4800, Christchurch, 8041, New Zealand