The Electrical Resistivity Tomography Technique for Landslide Characterization in Blangkejeren Aceh

Abstract

Investigation of geophysical methods describes elements and geological geometry based on the physical properties of the subsurface. In the past decade, the application of resistivity methods has experienced a rapid increase in describing geological structures and settings. The Electrical Resistivity Tomography technique used to describe the geometry of a complex landslide in Blangkejeren, Aceh province, Indonesia. This area is highly influenced by the landscape with slopes, high-rainfall, and tectonic activity of the Sumatran fault which can lead to soil movement. The type of landslides in this area is largely controlled by geo-structural characteristics; rotational and translational slides, as well as the phenomenon of the gravitational slope of high steepness. As a preliminary study, the acquisition of resistivity data was conducted at two locations with a length of each measuring path 330 meters and electrodes spacing 6 meters. The Supersting R8/IP instrument unit with Wenner-Schlumberger array is used to obtain data that has a sensitivity to vertical and lateral changes. The resistivity distribution along the path is obtained from both profiles that are perpendicular to the landslide field. ERT modeling results at both locations showed subsurface structures based on resistivity values such as; slate, clay, and sandy clay. The contrast resistivity between each layer makes it easier to describe the characteristics of the landslide slip plane geometry which is affected by the slope angle. The resistivity method has physical properties that are very sensitive to porosity and groundwater which is the main parameter in a landslide. Finally, it should be noted that the use of the ERT technique as an effective and efficient method in conducting landslide studies as a disaster mitigation effort.