Application of Electrical Resistivity Tomography (ERT) survey for investigation of the landslide: a case study from Taprang landslide, Kaski district, west-central Nepal

Abstract

The depth of the slip surface and thickness of the overburden deposit play a major role in assessing the slope stability of a landslide. Electrical Resistivity Tomography (ERT) survey was carried out in the Taprang Landslide, Kaski district, west- central Nepal to determine subsurface lithological conditions, depth and geometry of the slip surface. Wenner and dipole- dipole arrays were mainly applied in this ERT survey. The electrical resistivity survey revealed that there is a wide range of resistivity value which shows different kinds of layers in the subsurface, and the boundaries between these layers played a significant role to identify the slip surface. The data show mainly three layers from surface to bottom. An upper layer represents the dry to saturated colluvium and sandy gravelly soil (500 to 8000 Ωm), the middle layer is highly –saturated soil with low resistivity value (100–700 Ωm) and unweathered fresh bedrock of schist and quartzite with high resistivity value (1000 to 8000 Ωm) at the bottom layer. The slip surface is considered as depth 25 m at the crown, 10–20 m at the main body part, and below 50 m at the toe and curved in geometry which indicates the rotational type of landslide. Investigation of the slip surface in a landslide using the ERT survey aids to know the slope stability.

Estimation of soil overburden thickness/depth of rock strata using geo-physical survey at Himalayan region

“…The feasibility of various direct and indirect geophysical techniques resolves details of subsurface slope forming materials present there, such as ground water movement, thickness, bed rock relief, and water saturated zone (Bogoslovsky, 1997;Mills, 1990;Caris, 1991;Mauritsch, 2000). Recently, the role of electrical resistivity tomography (ERT) investigations has gained wide practice, mainly due to cost and time parameters (Meng, 2020;Sigdal, 2020;Koyode, 2019, Loke, 2013.…”

Application of electrical tomography technique for landslide investigation: Case of the Kef Essenoun phosphate deposit, Djebel Onk (Northeastern Algeria)

“…In applied geophysics, different tools that can be deployed to gather valuable subsurface data, namely seismic reflection and refraction [Hack, 2000], gravimetry [Gaudio et al, 2000;Perrone et al, 2012], georadar [Borecka et al, 2015;Jongmans and Garambois, 2007] and electrical resistivity tomography [Fehdi et al, 2011]. The latter is considered the most used in landslides investigation [Sigdel and Adhikari, 2020].…”

Slip Surface Identification for Landslide Hazard Mitigation With Electrical Resistivity Tomography

“…One of the geophysical methods that can be used to determine subsurface lithology is the Electrical Resistivity Tomography (ERT) method. The resistivity ERT method has often been used to detect subsurface lithology in order to identify potential landslides in an area based on the resistivity properties of the soil or rock in the area [9]. The ERT method, which has the characteristics of high spatial resolution, low-cost field data acquisition process, and relatively fast process, was used to predict the investigated landslide geometry (e.g., sliding plane depth and the geometry of the material involved) than other geophysical methods [9].…”