Landslide Hazard Evaluation Factor Research Articles

Landslide Hazard Zonation of Tehri Reservoir Rim Area Using Modified LHEF Rating Scheme

The study aimed to utilize the capabilities of geospatial technology for landslide hazard evaluation factor (LHEF) scheme recorded in the Bureau of Indian Standard (BIS) code to prepare a landslide hazard zonation (LHZ) map of the Tehri reservoir rim area at the macro-scale. Multisource remote sensing data were visually and digitally interpreted to produces thematic layers and slope facet as recorded in BIS method. LHEF method is suited for meso and macro scale mapping thus, to broaden the scope of LHEF scheme, novel approaches were adopted namely, the mapping unit ‘slope facet’ was more precisely extracted through digital and visual interpretation of remote sensing data, the structural favorability map was extracted using photo-lineament density criteria. Additionally, two external factors, rainfall and seismicity were incorporated in LHEF rating scheme and used a matrix-based system to propose their combined rating. With the modified LHEF rating scheme, we have succeeded in identifying LHZ with reasonable accuracy. The bar chart method used to validate LHZ results that clearly indicated a high number of landslides falling in high to very high hazard zone conversely, very few landslides observed in low to very low hazard zone identified from current approach.

Categorization of Slope Failure in Southern Malaysia using Total Estimated Hazard (TEHD) Method

Slope is a measure of steepness or the degree of inclination of a feature relative to the horizontal plane. One of the phenomenon or incidents of a slope was called as slope failure or landslide. Slope failure was a major natural disaster that had affected the country in terms of injuries, deaths, property damage, destruction of services, public inconvenience and economic as well as financial losses. Slope failure cases were very serious geologic hazard disaster that happened in many countries around the world. The aim of this paper is to determine the category of slope failure in the state of Johor based on Landslide Hazard Zonation (LHZ). Data were calculated by using Total Estimated Hazard (TEHD) value method which considered six factors effecting the slope failure, including lithology; slope steepness, topography, land use class, annual rainfall and type of soil. Data on the factors were collected from Malaysia Public Works Department (JKR) inspection form, website, and secondary data resource. After that weight for each factor were identified by referring to Landslide Hazard Evaluation Factor (LHEF) rating scheme. Then determination of LHZ was done according to TEHD values which have five hazard zones; (1) very low; (2) low; (3) medium; (4) high; and (5) very high. The results of this study found that out of total fifty two cases there were three medium hazard (MH), twenty seven high hazard (HH) and twenty two very high hazard (VHH). Comparison between actual data from JKR and total 52 locations of slope failure in Johor showed that 94% accuracy, TEHD equation could calculate potential slope failure hazards in Johor very well.

Landslide hazard zonation mapping and cut slope stability analyses along Yercaud ghat road (Kuppanur\u2013Yercaud) section, Tamil Nadu, India

In the present study, the macro landslide hazard zonation (LHZ) mapping and slope stability analyses of selected rock slope (RS) sections were carried out along Kuppanur–Yercaud ghat road section. The macro LHZ map was prepared on 1:50,000 scale using landslide hazard evaluation factor (LHEF) rating scheme proposed by Bureau of Indian Standard IS 14496 (Part-2) 1998. The study incorporated predefined ratings for different causative factors viz. lithology, structure, slope morphometry, relative relief, land use and land cover, and hydrogeological condition as well as triggering factors like seismicity and rainfall. The total estimated hazard (TEHD) was evaluated by adding ratings of all the causative factors. On the basis of TEHD values, the facet 3 with TEHD value 6.25 was classified as high hazard zone (HHZ). The facet 2 and 4 with TEHD values 5.50 and 5.40 respectively was classified as moderate hazard zones (MHZ). The facet 1 and 5 with TEHD values 2.20 and 3.15 was categorized as very low hazard zone (VLHZ). The slope stability analyses were carried out in six RS sections using rock mass rating (RMR) and slope mass rating (SMR) systems and the factor of safety (FOS) was evaluated for critical discontinuity sets. The results of RMR show that RS sections 1, 2, 4, 5, and 6 fall in class-III fair rock category, whereas the RS section 3 falls in class-IV poor rock category. The SMR method involves field measurement of slope and discontinuity orientation. These structural values were plotted in the stereonet and identified possible direction and mode of failure. The results of SMR show that the rock sections 1, 2, 4, 5, and 6 falls under partially stable condition, while the rock section 3 comes under unstable condition. The FOS of the critical discontinuity sections was evaluated for planar as well as wedge failure modes. The results based on planar failure analysis, the RS-2 and RS-3 having FOS < 1 are more unstable for slope failure. The wedge failure analysis shows that all the RS sections having FOS > 1 fall in safe conditions.

Landslide Hazard around Mussoorie: The Lesser Himalayan Tourist Destination of Uttarakhand, India

Identification of hazard prone areas and regulation of developmental initiatives in these is the key to disaster risk reduction. Slope instability is the most common hazard in all hilly areas and inherent fragility of the terrain makes Himalayan region all the more susceptible to landslides. Landslide hazard evaluation factor rating scheme is utilized for delineating areas prone to slope instability in the proximity of Mussoorie that is a major tourist destination of Uttarakhand in India. Of the 58 Sq. km area taken up under the study 18.4, 12.5 and 1.0 Sq. km. respectively fall under moderate, high and very high landslide hazard class. Detailed stability assessment is therefore recommended for developmental initiatives in moderate hazard class while regulating anthropogenic intervention is recommended in both high and very hazard classes.

Landslide hazard zonation mapping in ghat road section of Kolli hills, India

Landslides are the most common natural disaster in hilly terrain which causes changes in landscape and damage to life and property. The main objective of the present study was to carry out landslide hazard zonation mapping on 1:50,000 scale along ghat road section of Kolli hills using a Landslide Hazard Evaluation Factor (LHEF) rating scheme. The landslide hazard zonation map has been prepared by overlaying the terrain evaluation maps with facet map of the study area. The terrain evaluation maps include lithology, structure, slope morphometry, relative relief, land use and land cover and hydrogeological condition. The LHEF rating scheme and the Total Estimated Hazard (TEHD) were calculated as per the Bureau of Indian Standard (BIS) guidelines (IS: 14496 (Part-2) 1998) for the purpose of preparation of Landslide Hazard Zonation (LHZ) map in mountainous terrains. The correction due to triggering factors such as seismicity, rainfall and anthropogenic activities were also incorporated with Total Estimated Hazard to get final corrected TEHD. The landslide hazard zonation map was classified as the high, moderate and low hazard zones along the ghat road section based on corrected TEHD.

Landslide hazard zonation around Gilgel Gibe-II Hydroelectric project, Southwestern Ethiopia

The present study was carried out along the newly constructed road from Fofa town to Gilgel Gibe-II powerhouse in South western Ethiopia. In this study, an attempt has been made to provide information on the landslide hazard zones present along the new road. In order to delineate the hazardous zones the landslide hazard evaluation factor rating scheme (LHEF) proposed by Anbalagan (1992) has been utilized. The LHEF rating scheme is based on an empirical approach which combines past experience gained from the study of causative factors and their impact on landslides with conditions anticipated in the area of study. For LHEF rating scheme data on major inherent causative factors of slope instability such as geology, slope morphometry, relative relief, land use and land cover and ground water conditions has been collected. Based on the evaluation values, the slopes in the study area have been classified for landslide potential as; High Hazard, Moderate Hazard and Low Hazard. The results of the present study indicate that 54% of the slopes in the study area fall in High Hazard, 34% in the Moderate Hazard and 12% in the Low Hazard zones. Thus, the Landslide Hazard Zonation shows that chances of slope failures are high in the study area.

Macro Landslide Hazard Zonation Mapping - Case Study from Bodi – Bodimettu Ghats Section, Theni District, Tamil Nadu - India

Landslide is a common natural hazard that usually occurs in mountainous areas. Rapid urban development and high traffic intensity movements have been hampered to a great extent by phenomenon of landslides. In Ghat section, vertical cuttings and steep slopes are induced slope failures. An assessment of landslide hazards is therefore a prerequisite for sustainable development of the hilly region. In the present study, Macro Landslide Hazard Zonation was carried out in the Bodi – Bodimettu ghats section, Western Ghats, Theni district. The slope spreads over an area of about 10.09 sq km encompassing Puliuttu Ar. sub-watershed. The study was made with help of different types of data including Survey of India topographic map, geology map, important inherent factors like lithology, structure, slope morphometry, relative relief, land use/land cover and hydrogeological conditions using Bureau of Indian Standard (BSI 14496 (Part 2):1998) and related thematic maps. Based on the thematic layers, landslide hazard evaluation factor (LHEF) and total estimated hazard (TEHD) were calculated and the macro hazard zonation map was prepared. Landslide Hazard Zonation (LHZ) of the terrain shows that out of 17 facets, facets 1 to 5 and 8 falls under Moderate Hazard zone category and facets 6, 7 and 9 to 17 under the High Hazard zone category. The field study with further analysis for hazard concluded that about 68% of the total area falls in the high hazard zone.

A comparative study of fuzzy logic approach for landslide susceptibility mapping using GIS: An experience of Karaj dam basin in Iran

Preparation of landslide susceptibility maps is important for engineering geologists and geomorphologists. However, due to complex nature of landslides, producing a reliable susceptibility map is not easy. For this reason, many procedures have been used to produce such maps. Among various models this paper discusses the effectiveness of fuzzy logic approach for landslide hazard mapping. In this study a new attempt is tried to produce landslide susceptibility map of Karaj Dam Basin in Iran. To obtain the fuzzy relations for producing the susceptibility map, a landslide inventory database is compiled by both field surveys and airphoto studies. The factor maps were input into a GIS and a modified landslide hazard evaluation factor (MLHEF) rating and fuzzy membership functions as well as belief function values were assessed for each class of the factor maps. According to this map, 10% of the study area is classified as very high susceptibility, 23% as high susceptibility, 38% as moderate susceptibility, 4.5% as low susceptibility and 0.5% as very low susceptibility or nonsusceptible areas .the results show that the fuzzy set theory can integrate effectively various spatial data for landslide hazard mapping, and it is expected that some suggestions in this study are helpful to further real applications including integration, and interpretation stages in order to obtain a decision – supporting layer.

Landslide hazard potential mapping using landslide hazard evaluation factor with GIS approach

Landslide hazard potential mapping using landslide hazard evaluation factor with GIS approach

Landslide hazard zonation mapping of Tapovan - Helong hydropower project area, Garhwal Himalaya, India, using univariate statistical analysis

Landslide hazard zonation mapping of Tapovan - Helong area of Garhwal Himalaya, where a hydropower scheme of 520 MW is proposed on Dhauli Ganga was carried out. The study area lies in the Main Central Thrust (MCT) zone, which receives majority of the southwest summer Monsoon. The study area belongs to Central Crystalline zone consisting of medium to high grade-quartz-plagioclase-muscovite-biotite-garnet-kyanite and sillimanite bearing crystalline rocks. In the present study statistical analysis of various geo-environmental factors such as the lithology, slope, structure, relative relief, landuse and hydro-geological conditions were used. For preparing the landslide hazard zonation map a quantitative approach called landslide hazard evaluation factors (LHEF) rating has been used. The study indicates that structures, peri-glacial material resting on steeper angle of hill slopes and rainfall plays major role in triggering landslides in this part of the Himalaya. The main aim of this study was to select the best locations for the construction of barrage and sedimentation tank, selections of sites for the tunnels portal and the switchyard area and finally appropriate slope stabilization measures were also suggested. The study further suggests that in the investigation stage for river valley projects, landslide hazard evaluation factor (LHEF) rating scheme can provide rapid hazard assessment in a mountainous terrain.

Landslide hazard zonation in Hanuman Chatti area of Uttarakhand, India

PurposeThe purpose of this paper is to evaluate landslide hazard problems in Hanuman Chatti area of Uttarakhand, India. Every year NH 58 experiences landslide activities, which disrupts the tourist traffic to Badrinath shrine and higher Himalaya.Design/methodology/approachAn urgent need is being felt to have a comprehensive landslide hazard evaluation factor (LHEF). The major causative factors that influence the slope stability are lithology, structure, soil depth, soil texture, geomorphology, slope morphology, slope dip, slope aspect, slope magnitude, weathering, land use and land cover and anthropogenic activities. The present analysis is based on the rating scheme in which numerical ratings for different categories are determined on the basis of their estimated significance in causing instability.FindingsIn the study area, nine old landslides (0.238 sq.km) and five new landslides (0.086 sq.km) are recorded. On the basis of the various causative factors the study area is classified into five landslide hazard classes.Research limitations/implicationsThe analysis is based on the experience gained for the last seven years (1999‐2007). The period is short for developing any hypothesis but sufficient care has been taken to consider vital factors.Practical implicationsWith the help of LHEF appropriate landslide hazard management tools can be adopted. Once a LHEF rating scheme in which numerical ratings for different categories are determined on the basis of their estimated significance in causing instability, is standardized it can be applied to the entire Himalayan region, which is very prone to landslide hazard.Originality/valueAlthough the paper is an attempt to evaluate the efficacy of landslide hazard zonation techniques developed by various agencies in the past, some modification as per the requirement has been made in various stages of investigation.

Landslides susceptibility mapping in Guizhou province based on fuzzy theory

The purpose of this study was to assess the susceptibility of landslides around the area of Guizhou province based on fuzzy theory. In first instance, slope, elevation, lithology, proximity to tectonic lines, proximity to drainage and annual precipitation were taken as independent, causal factors in this study. A landslide hazard evaluation factor system was established by classifying these factors into more subclasses according to some rules. Secondly, a trapezoidal fuzzy number weighting (TFNW) approach was used to assess the importance of six causal factors to landslides in an ArcGIS environment. Thirdly, a landslide susceptibility map was created based on a weighted linear combination model. According to this susceptibility map, the study area was classified into four categories of landslide susceptibility: low, moderate, high and very high. Finally, in order to verify the results obtained, the susceptibility map and the landslide inventory map were combined in the GIS. In addition, the weighting procedure showed that TFNW is an efficient method for weighting causal landslide factors.

A comparative study of Dempster–Shafer and fuzzy models for landslide susceptibility mapping using a GIS: An experience from Zagros Mountains, SW Iran

A catchment area at the Zagros Mountains, NW Shiraz, Iran is selected as a test site to comparing the output results of the Dempster–Shafer (D–S) and fuzzy models in landslide hazard mapping. Lithology, slope angle, slope aspect, land cover, and soil depth were considered as landslide causal factors. The factor maps were input into a GIS and a modified landslide hazard evaluation factor (MLHEF) rating and fuzzy membership functions as well as belief function values were assessed for each class of the factor maps. The fuzzy sum, product and gamma combination approaches were examined and output maps were assessed based on the known landslides. The outputs of fuzzy sum and product combination rules were not reasonable because these approaches classified the area into ’very-high’ or ’very low’ susceptibility zones respectively, which were not compatible to the field and factor maps criteria. A γ value of 0.94 yielded the most reliable susceptibility for landslides. Overlay of the known landslides with the output favorability map showed that the identified landslides were located in the high- and very-high susceptible zones. The output results of the Dempster–Shafer model: plausibility, belief, and uncertainty images were also evaluated based on the known landslides. The results of this approach revealed that although it was expected that most of the known landslides correspond the plausibility, or the belief map, only a few of them supported the case, and some landslides were coincided into the disbelief, or uncertainty maps. It is concluded that in comparison to the fuzzy model, the D–S model obtains less reliable results for landslide hazard mapping. Since the belief functions were assigned based on the fuzzy membership functions this might be due to the integration equations used by the model, or the number of evidence maps used as input layers.

Landslide hazard zonation mapping and comparative analysis of hazard zonation maps

Landslide hazard zonation mapping at regional level of a large area provides a broad trend of landslide potential zones. A macro level landslide hazard zonation for a small area may provide a better insight into the landslide hazards. The main objective of the present work was to carry out macro landslide hazard zonation mapping on 1:50,000 scale in an area where regional level zonation mapping was conducted earlier. In the previous work the regional landslide hazard zonation maps of Srinagar-Rudraprayag area of Garhwal Himalaya in the state of Uttarakhand were prepared using subjective and objective approaches. In the present work the landslide hazard zonation mapping at macro level was carried out in a small area using a Landslide Hazard Evaluation Factor rating scheme. The hazard zonation map produced by using this technique classifies the area into relative hazard classes in which the high hazard zones well correspond with high frequency of landslides. The results of this map when compared with the regional zonation maps prepared earlier show that application of the present technique identified more details of the hazard zones, which are broadly shown in the earlier zonation maps.

Reservoir sedimentation associated with landsliding, Atrak watershed, Iran

The Barezoo dam on the Gholjogh River, a branch of the Atrak River with a catchment area of 491.7 km 2 , is located about 18 km north of Shirvan city in NE Iran. Landslides are an important natural hazard in the Atrak watershed and cause serious problems for the maintenance of the Barezoo reservoir. Landslide occurrence is controlled by lithology, slope of the terrain, and natural and human actions that may either add to the operating gravitational stresses or reduce the resistance to sliding of the soils forming the slope. The interaction between local geology and climatic conditions in this area has resulted in landforms with varying degrees of susceptibility to landsliding. Dammed watersheds in NE Iran experience numerous landslide and sedimentation problems. A quantitative approach based on a numerical rating scheme called the landslide hazard evaluation factor rating scheme was used to evaluate and describe landslides and their resultingsedimentation in the Gholjogh watershed.

Landslide hazard evaluation and zonation mapping in mountainous terrain

Landslide hazard zonation (LHZ) maps are of great help to planners and field engineers for selecting suitable locations to implement development schemes in mountainous terrain, as well as, for adopting appropriate mitigation measures in unstable hazard-prone areas. A new quantitative approach has been evolved, based on major causative factors of slope instability. A case study of landslide hazard zonation in the Himalaya, adopting a landslide- hazard evaluation factor (LHEF) rating scheme, has been presented.