Active Fault Identification Using a High-Resolution DEM from UAV mounted LiDAR and Resistivity Tomography Survey: Matano fault, Central Region of Sulawesi, Indonesia

Abstract Indonesia is known as a country that experiences earthquakes very often, characterized by fairly frequent earthquake activity in recent years, so there is a need for many studies conducted on active faults in an effort to mitigate the risk of earthquake disasters. This fault activity may produce surface fracture or scarp, which fault scarps are topographic features and geomorphological markers along mountain range-fronts. The Matano Fault, which runs NW-E for ∼170 km, is one of the active faults in Sulawesi that has a left strike-slip movement mechanism as a result of the rapid westward movement of the Pacific plate relative to the Australian plate. In Mangkutana sub-district, East Luwu regency, South Sulawesi, where it is the west side of Matano Faults, there are an indications of fault scarps, but the available data are only DEM data from DEMNAS with 8 m resolution, which it is not sufficient to trace the active fault due to vegetation cover in case to locate trenching location. This study presents the results of topographic interpretation or DEM using LiDAR survey to get more detailed results and strengthened with resistivity tomography imaging. From the survey results, a new fault line interpretation was obtained that is different from the PuSGeN fault line. The fault line interpretation uses DTM and DSM data obtained from the LiDAR survey results within four zone. The active fault feature is located on the northeast side of the Kalaena River where it improve/update fault model of the 2017 PuSGeN active fault input parameters. We identified strike-slip fault feature as a shutter ridge, river offsets, fault scarp lineament, and geophysical resistivity tomography intrepretation. Further paleoseismology study is needed to confirm the age, magnitude size, last event and sliprate on the Holocene period.