Risky Martin Antosia, Fitri Pangaribuan, Dadan Dani Wardhana
Landslide disasters frequently occur in Tasikmalaya Regency, with Salawu Village being at a medium to high ground movement vulnerability zone. Steep slopes and quite high rainfall dominate this area. This study aims to identify subsurface rock types and model the slip plane by applying the dipole-dipole configuration of the 2D geoelectrical method. The result can be used as a mitigation measure to minimize losses if a landslide disaster occurs. We measured the resistivity in five lines with spacing between electrodes of 5 m with a total length of 275 m. The data processing results indicate three classes of resistivity values: a resistivity value under 25 Ωm is interpreted as sandy clay, a value in the range of 20-105 Ωm as clayey/ tuffaceous sand, and a resistivity of more than 80 Ωm as volcanic breccia. The slip area is sandy clay with a slipping mass of clayey/ tuffaceous sand and volcanic breccia. Two of the surveyed lines have safety factor values less than 1.00 (the slope is approximately 40°, and the slip plane angle is between 33° and 35°), which means that the area has an unstable slope. The small safety factors should be a serious concern because landslides can occur at any time. Moreover, breccia rock is one of the landslide materials that would have a very destructive impact. To confirm the results of this study, in situ geomechanical tests are needed in this area. © 2023 The Author(s).
Geophysical Engineering Department, Faculty of Industrial Technology, Sumatera Institute of Technology, Indonesia; Research Center for Geological Disasters, National Research and Innovation Agency (BRIN), Indonesia