Preliminary Result: Identification of Landslides Using Electrical Resistivity Tomography Case Study Mt. Betung (original) (raw)
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IOP Conference Series: Earth and Environmental Science
Landslide is a geological event that occurs because the movement of slope-forming material in the form of soil, rock or combination of material type to a lower place due to the influence of gravity. The trigger factor of landslide in Pasanggrahan, South Sumedang, Indonesia is the increase of water content in the slope and the slip plane. The slip plane began to actively to turn on when the rainy season arrives. The infiltration of rainwater into slopes as an avalanche trigger can be detected by Self Potential (SP) method. SP measurements were performed to determine changes in subsurface water flow. SP data acquisition using fixed base technique and leap frog technique. The rocks in the research area that serve as the slip plane are clays associated with Volcanic Breccia. One of the geophysical methods that can identify the slip plane is the Electrical Resistivity Tomography Method. The ERT method can detect slip plane based on rock resistivity. Based on the local geology that has be...
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 Wm), the middle layer is highly-saturated soil with low resistivity value (100-700 Wm) and unweathered fresh bedrock of schist and quartzite with high resistivity value (1000 to 8000 Wm) 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.
2014
The electrical resistivity tomography (ERT) survey has been deployed to accurately shed more light of a small landslide located near the Buzad village, Timis County, Romania. This slide actually represents a local reactivation during 2006 of an old landslide. A 2-D resistivity survey along three profiles over the landslide main body using a Wenner configuration was performed in 2007, 2012 and 2014. The results obtained provide useful information about the geometry and characteristics of the landslide, the depth and extension of landslide body. The ERT measurements indicated some zones associated with both the high water content and the clay content within the landslide body, divided by a compact sandstone mass that influenced the slide development.
Determination of the Landslide Slip Surface Using Electrical Resistivity Tomography (ERT) Technique
Advancing Culture of Living with Landslides, 2017
Indonesia is located among three interacting active tectonic plates, causing the country to become vulnerable to geological disasters; landslides being one of them. Deforestation and overpopulation on the hillsides have escalated the formation of critical areas where landslides and other geological disasters are an occurrence. It is therefore important to study the geometry and the depth of the slip surface of a critical area in order to recognize the indicator of landslides. In situ geophysical techniques enable the measurement of physical parameters, either directly or indirectly (via satellite), linked with the lithological, hydrological and geotechnical characteristics of the terrains related to landslides. The objective of this research is to determine slope stability analysis using a geophysical method described as Electrical Resistivity Tomography (ERT). Data from 1-D and 2-D Electrical Resistivity Tomography (ERT) analysis conducted in Cianjur, West Java-one of the most critical areas for landslides due to its steep hilly areas-showed that there was a contrast in the resistivity value. It showed different kind of layers in the soil, and the boundaries between these layers played a role as a slip surface. The data also showed that there were two slip surfaces in the research area: at the bottom and the top of the slopes. These provided the margins between the higher resistivity value of the upper layer and the lower resistivity value of the lower layer. The upper layer was concluded as clay soil and the lower one as more sandy soil. Determining slip surface using ERT helps to analyze the stability of the slope.
Recent Trends in Application of Electrical Resistivity Tomography for Landslide Study
https://link.springer.com/book/10.1007/978-981-13-2116-0, 2019
Landslide disasters are known to be complex geological event with high socioeconomic effects in terms of loss of lives and properties. Landslide study involves the application of a multidisciplinary approach. Various techniques involving both surface and subsurface methods have been applied to investigate and understand the mechanism of its occurrence. Application of geophysical tools is one of such advanced techniques. In this paper, the recent trend in application of Electrical Resis-tivity Tomography (ERT) technique is being studied as it is a noninvasive method for investigation. ERT technique has been used widely for various landslides from rockfall to debris flow. The method has been applied to various geological conditions and environment to identify the slip surface, hydrological conditions, reconstruction of the slope body, estimation of the sliding materials volume/thickness, and depict the internal structures. Various array used in the measurement along with the algorithms for topographic inversion are also discussed. The results of 2D, 3D and 4D ERT techniques used in the recent times have been discussed. Future prospects and the limitations are also discussed.
International Journal on Advanced Science, Engineering and Information Technology
Extreme weather triggers high-intensity rainfall, and it triggers land movement that eventually becomes landslides. The water of rain will enter to the ground through the rock gaps and accumulate along the landslide area to reduce effective stress and reduce the shear strength of the soil. Morphologically, Sukaresmi Village, Cisaat Sub-District, Sukabumi Regency is located at the foot of Mount Gede with a bumpy surface relief. This condition is one factor that triggers landslides because the soil is prone to movement. This research aims to identify the field slope zone for landslide prediction in the Sukaresmi village, hoping that the surrounding community could anticipate further landslides. The research was carried out using the Geoelectrical Resistivity method of the Schlumberger configuration as many as eight measuring points with 1 m electrode spacing. This research indicates that the subsurface conditions are divided into three constituent rocks: Clay, Tuff, and Volcanic Breccia. The field slide zone is located between the Tuff rock and turf layer at a depth of 4-7. 5 m long, 82 m (Line 1), and 40 m (Line 2), with a resistivity value range of 56-158 Ωm. The efforts that the local government can make to anticipate the condition of the building to remain safe include analyzing soil stability, strengthening slopes, and making retaining walls to increase the value of the safety factor.
Slip Surface Identification for Landslide Hazard Mitigation with Electrical Resistivity Tomography
Indonesian Physical Review, 2022
Barisan Hill complex, has been affected by the Sumatran fault movement and the Lampung-Panjang fault so that the morphological condition is hilly with steep slopes, which causes the risk of natural disasters such as landslides. In this article, the identification of subsurface rock lithology and sliding plane in the landslide-prone zone is carried out using the Wenner-Schlumberger configuration geoelectric method. Based on the Wenner-Schlumberger configuration, the top layer has lithology clay tuff and sandy tuff, which predicted a weathered rock with a resistivity of 1-133 ohm.m. Coarse-grained tuff and fine-grained tuff with resistivity values of 135-250 ohm.m in the middle. The bottom layer has a resistivity of more than 250 ohm.m, that predicted to have a lithology breccia (igneous rock) Tarahan Formation. The sandy clay layer (81-90 ohm.m) predict as a sliding plane in this area, at depths of 8.2 to 16 m. The type of landslide developed in the research area is a crawling soil landslide, with very steep slope characteristics (8 0-35 0).
Near Surface Geoscience 2015 - 21st European Meeting of Environmental and Engineering Geophysics, 2015
We report on the results of geological, geotechnical and geophysical surveys for the characterization of a landslide, occurred in the Asti Reliefs (NW Italy) during the first ten days of March 2011, just after an exceptional meteoric event. The investigated landslide is located in San Damiano d'Asti (15 km E of Asti) and involved a hilly side, gently sloping. The hazard situation in this area regards a landslide that involved the back of a building. This landslide was caused by excavations made in the time at the toe of the slope with the aim to extend the narrow flat spaces. The contribution given by Electrical Resistivity Tomography (ERT) was essential, in the first phase of the investigation, to recognize deep and localized water seepage, otherwise undetectable. The identification of saturated clays into the slope allowed us to design the correct re-profiling of the scarps and make digging operations in safety. The use of these methods of investigation has a significant economic savings in the choice of interventions for slope stabilization.
Jurnal Penelitian Pendidikan IPA
Kastoba Lake in Bawean Island Indonesia is a tourist attraction that has a level of vulnerability in landslide disasters. The landslides has been happen. From the large and small scale in the Kastoba Lake. Base on the problem, the landslides occured due to the field of derailment. According to the above statement, it was necessary to know the subsurface structure and the field of avalanche derailment in the kastoba lake area. This data was allowed by geophysical resistivity method which a dipole-dipole configuration with 4 measurement points. The acquisition of data was based on preliminary studies from the analysis of landslide vulnerability level maps (DEM Alos data processing) that have been done first. The results of lithological analysis with geoelectric resistivity methods in this research obtained three layers of subsurface structure, namely top soil (top layer) with a resistivity value of 7-110 Ωm, clay (middle layer) which was a resistivity value of 110-210 Ωm and lava (bot...
2017
Landslides are phenomena that can be very complex and their study requires geological and geomorphological mapping, geotechnical and geodetic study and also geophysical investigation. Geophysical techniques that can provide valuable information on physical parameters, may be directly or indirectly an indicator for the mechanism of landslide phenomena (JONGMANS & GARAMBOIS, 2007). The Electrical Tomography is known to help in engineering geology problems due to electrical resistivity variations between the basement rocks and overlaying sediments, which form an unconsolidated cover. As a rule, the basement rocks are more compact and show higher electrical resistivity values, compared to the loose sediments of the cover, consisting of clays, silts and sands. The first several meters though, in dry season, have higher resistivity values compared to the sediments of the cover saturated with water (below water table). In this paper the geophysical study of a landslide taking place in Pris...