Mapping landslide vulnerability using subsurface rock elastic parameters: A case study of Lebong Regency, Bengkulu

The Ketahun segment fault, a part of the Sumatran Fault that crosses through Lebong Regency in Bengkulu Province, Indonesia, has the potential to trigger on-land earthquakes, leading to landslides. Our research, conducted with utmost meticulousness, aims to map landslide potential using the Analytical Hierarchy Process (AHP). We thoroughly analyse various parameters, including rock elasticity, fault distance to measurement points, rainfall, slope and elevation, land cover, ground shear strain (GSS), the time-averaged shear wave velocity for the first 30 m depth (V_s30), peak ground acceleration (PGA), and modified Mercalli intensity (MMI). The data acquisition process involves the field survey and secondary data collection. The latter is conducted to support the analysis and input of field survey data. The field survey entailed collecting microtremor data using the Horizontal Spectral Ratio (HVSR) method. Subsequently, microtremor data recorded through the HVSR method were processed using win-MASW 5.2 HVSR software. Based on these results, we can identify areas with potential landslides based on rock elastic parameters. The landslide potential map, performed by overlaying these parameters using AHP statistical weighting, highlights the dominant influence of landslide potential stemming from the GSS value, distance of faults to the measurement points, slope gradient, and high rainfall in the study area. In regions exhibiting a high potential for landslides, it is imperative to exercise caution and prepare for disaster mitigation activities to mitigate the risk of such occurrences.