Subsurface Lithology Modelling of Landslide-Prone Areas in Sriharjo, Bantul Using the Geoelectrical Method

Lithology modeling in a landslide-prone area using the geoelectrical method with the Wenner configuration.The research aims to determine resistivity values, subsurface lithology, and slip surfaces in Sriharjo Village, Bantul Regency, which frequently experiences landslides.This area is identified as one of the most vulnerable zones due to its steep slopes and geological conditions.Sriharjo Village, located along the Opak Fault, is a critical area where landslides have repeatedly caused significant losses.Data were collected along four 225-meter survey lines with 15-meter electrode spacing and an expansion factor up to n = 5.The data were processed with Res2Dinv to obtain resistivity values and two-dimensional subsurface profiles.Results show resistivity values ranging from 0.0397 m to 1046 m.The subsurface is divided into aquifer, clay, and breccia layers, with slip surfaces occurring in the clay and breccia layers, which display both curved and flat geometries.By identifying the slip surface and the thickness of the weathered layer above it, the landslide potential in this area can be assessed, helping to reduce casualties and minimize material losses.