Slope Stability Analysis for Landslides Natural Disaster Mitigation by Means of Geoelectrical Resistivity Data in Gedangan of South Malang, East Java, Indonesia

Abstract

A study entitled slope stability analysis for landslides natural disaster mitigation by means of geoelectrical resistivity data in Gedangan of South Malang, East Java, Indonesia has been conducted. This study aims to obtain the physical parameters that cause landslides that occur in Gedangan village, Gedangan sub-district, Malang district. The research was conducted using geoelectrical resistivity method by applying a vertical electrical sounding (VES) model and Wenner-Schlumberger configuration. From the data as a result of field data acquisition, processing and interpretation are carried out to obtain landslide parameters. By merging each vertical electrical sounding (VES) point, physical parameters will be obtained as the basis for local landslide analysis. The results of the cross-sectional line A (GED4-GED1-GED2) indicate the presence of an average slope surface or topography that is relatively parallel with the average slope sliding plane which is about 7° whereas line B (GED1-GED3-GED5) is around 15°. The average thickness of the overlying layer in the slip plane both on line A and line B is around 65m. The slope condition of the slip plane (angle and thickness of the layer) indicates an unstable condition. For stable conditions F> = 1.2, the maximum thickness of the cover layer at line A is 54 m while in line B is 8.2 m. For stable conditions F> = 1.5, the maximum thickness of the cover layer for line A is 25.5 m while in line B is 5.85 m. To overcome the landslide, the proposed solution was by doing a reduction/dredging of the cover layer or installation of the bored piles.