Analysis of Landslide Slip Surfaces Using Geoelectrical Methods : A Case Study in Cianjur, West Java, Indonesia Rizky Kurniawati (a), Arif Laksana (a), Masrinaldo (a), Wahyu Srigutomo (a), Nurhasan (a), Enjang Jaenal Mustopa (a*)
Earth Physics and Complex Systems Reseacrh Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jalan Ganesa 10, Bandung 40132, Indonesia
Abstract
Cianjur is located in a high earthquake hazard zone. Earthquakes can trigger secondary disasters, one of which is landslides. One of the most influential factors causing landslides is the slip surface. One method that can be used to investigate the slip surface is the geoelectrical method. The slip surface is generally located between zones with low and high resistivity values. Therefore, this study aims to analyze the slip surface associated with landslides that occurred in Cianjur using the geoelectrical method. Data acquisition was carried out using the Wenner-Schlumberger configuration with a survey line length of 80 m and an electrode spacing of 5 m at two different locations in Cianjur Regency. At Location 1, two survey lines were measured, while at Location 2, four survey lines were conducted. The results show that at Location 1, the subsurface resistivity ranges from 6 Ohm-m to 611 Ohm-m. The depth of the slip surface at Location 1 ranges from 3.75 to 12.6 m. At Location 2, the subsurface resistivity ranges from 1 Ohm-m to 3205 Ohm-m. The depth of the slip surface at Location 2 ranges from 6.38 to 9.25 m. This layer is interpreted as clayey sand or more compact silt, which acts as a boundary between compact sandstone with high resistivity and water-saturated clay with low resistivity.
