DETERMINATION OF NEAR-SUBSURFACE BY USING 2D RESISTIVITY METHODS (CASE STUDY OF LANDSLIDE MONITORING AT PANAWANGAN AREA CIAMIS, INDONESIA)

• Main Author: (NIM 22304009), Syamsudin
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/6823
• Institution: Institut Teknologi Bandung

ABSTRACT: <br /> <br /> <br /> <br /> One of the natural hazards that is often occurred in Indonesia is landslide. This hazard occurs normally in area which has high density of population. Thus, if they are happened could caused a big number of victims, damage and property loss. Landslide is a geological phenomenon which includes a wide range of ground movement, such as rock falls, deep failure of slopes and shallow debris flows. The hazards will happen if gravitys action on an over-steepened slope is getting larger, which caused the material fall down from its initial equilibrium. The increase of water content inside earth material is the primary reason for a landslide. <br /> <br /> <br /> <br /> The potential of landslide can be detected by applying geophysical methods; one of them is 2D resistivity method. This method has been used to determine the near subsurface structure of the earth including detection of landslides slip plane. This Method is an indirect method, in which the results of this method could give an overview of resistivity distribution inside subsurface. There are several kinds of electrode configurations. Two of them, namely wenner alpha and wenner-beta, have been use in the study area at panawangan area, Ciamis. Base on synthetic study that has been carried out, wenner alpha configuration is sensitive in detecting resistivity changes is vertical direction. Where as, Wenner beta configuration is sensitive in detecting resistivity changes in both vertical and horizontal directions. The results of inverted resistivity data showed the same characteristics as have been proved in synthetic study. Processing of resistivity data used RES2DINV software. <br /> <br /> <br /> <br /> The obtained results of the study show that some contracts between low and high resistivity values in some part of the sections could be the position of slip plane inside subsurface. Those contrasts are interpreted boundary between old volcanic breccias of Cijulang Formation (more compact) and young breccias of Gunung Sawal Formation (less compact). This interpretation has a good agreement with the result of Ground Penetrating Radar (GPR), which show the existence of strong reflection on the same location.