Using DInSAR to map ground deformation on road infrastructure (case study: North Buton, Southeast Sulawesi)

Abstract

The mapping of ground deformation is an essential activity in the context of disaster mitigation. Road networks which susceptible to landslides due to soil surface instability need to be mapped as initial information for regular monitoring and maintenance activities. This information is also vital for the community to increase its capacity and preparedness in facing landslides. This study aims to map ground deformation on road infrastructure in North Buton regency, Southeast Sulawesi Province. We applied Differential Interferometric Synthetic Aperture Radar (DInSAR) method based on four Sentinel-1 single look complex (SLC) images from the 2019 and 2020 acquisition. Data processing includes the SLC co-registration, interferogram formation, phase unwrapping, and geocoding. From the research, we obtained the occurrence of land subsidence and uplift area in the study location. The land subsidence occurred -64 mm to -129 mm per year and uplift up to +65 mm per year. Conditions in the field obtained through direct surveys found landslides and cracks in the road body. From geology map analysis, the ground deformation probably influenced by the fault activity near the study location.