Landslide Hazard Zonation Map Research Articles

Landslide hazard zonation assessment using GIS analysis at the coastal area of Safi (Morocco)

Abstract. Landslide hazard is one of the major environmental hazards in the coastal area. For helping the planners in selection of suitable locations to implement development projects, a landslide hazard zonation map has been produced for the coastal area of Safi (Morocco) as part of coastal Meseta. For this purpose, after preparation of a landslide inventory of the study area, some major parameters were examined for integrated analysis of landslide hazard in the region. The analyses of parameters were done by geo-referencing and lateral model making, satellite imaging of the study area, and spatial analyses by using geographical information system (GIS). The produced factor maps were weighted with analytic hierarchy process (AHP) method and then classified. The study area was classified into four classes of relative landslide hazards: negligible, low, moderate, and high. The final produced map for landslide hazard zonation in coastal area revealed that: the parameters of slope, geologic formation and fracturation have strong correlation and predict 75% of existing instabilities.

Comparative Evaluation of GIS Based Landslide Hazard Zonation Maps Using Different Approaches

ABSTRACT Natural hazards like landslides in lesser Himalayan region of district Kullu (HP) India, owe to its typical geomorphic setting, variations in relief, precipitation during monsoon, thick forest cover, presence of glacier and glacial lakes along the higher reaches and various anthropogenic activities. Landslide locations, types and factor influencing the slope details are collected through the field visits and past record of landslides were used for development of inventory. Ancillary data are used for generation of different thematic layers (aspect, drainage density, geology, land cover, lineament density, relief, slope, and soil). Weight of evidence (WOE), information value(IV) and frequency ratio (FR) methods are used for generation of landslide hazard zonation (LHZ) maps which were classified into four zones namely high, moderate, low and very low. Validation and comparison of these hazard maps was done through the successive rate curve method which showed almost similar results, this proved the accuracy of these methods for generation of LHZ maps (WOE 80.01%, IV81.54% and frequency ratio 83.21%).

GIS-based comparative study of information value and frequency ratio method for landslide hazard zonation in a part of mid-Himalaya in Himachal Pradesh

The road network of a developing country plays a vital role in its overall development. It is therefore important to ascertain landslide hazard assessment along a road network. Landslide hazard zonation focuses on preparing landslide hazard map by considering major instability factors causing the landslides. The present study deals with geographical information systems-based landslide hazard zonation of the study area. The study area comes under the mid-Himalayan region of Himachal Pradesh, India. The slope failures create major havoc every year due to high frequency of landslides along the road. Eight major landslide-causing factors have been identified for the study area, which includes slope, relative relief, curvature, aspect, drainage density, lithology, lineament density, and land use/land cover. Corresponding to each landslide causative factor, a layer has been prepared and landslide hazard zonation maps of the study area were evolved by using frequency ratio and information value methods. Approximately, 75% of the total landslides which occurred in the study area were used for training purpose, and remaining 25% were used for the validation of results using the area under curve technique. The developed landslide hazard zonation maps show satisfactory agreement with the landslide inventory of the study area. The success rate curve obtained for frequency ratio method is 77.18%, and for information value method, it is 74.76%. The validation of result illustrates that frequency ratio method is more accurate as compared to information value method for the study area. The present study shows that geographical information system provides a better environment for modelling of the statistical techniques, that is, frequency ratio and information value method in the present study.

Landslide hazard zonation mapping using multi-criteria analysis with the help of GIS techniques: a case study from Eastern Himalayas, Namchi, South Sikkim

Landslides are one of the most damaging disastrous phenomena that frequently lead to serious problems in hilly areas. The Namchi region of South Sikkim district as a part of Eastern Himalayas is not an exception to it. In the present study, multi-criteria analysis technique is used for landslide hazard zonation mapping. Various thematic layers, namely slope, rainfall distribution map, lineament density, drainage density, slope aspect, geology, land use/land cover and soil map, were integrated in a GIS platform (ArcGIS 10.1) to delineate landslide hazard zone. Analytic hierarchy process was used to determine the weight values of different factors. Relative rating values are assigned for the subclasses of each thematic layer based on their corresponding impact on the landslide triggers, and within a thematic layer, each class was assigned an ordinal rating from 0 to 9. The landslide hazard zonation map of Namchi region was produced based on weighted overly techniques. The landslide hazard map of Namchi region is divided into five vulnerable zones, namely very low-, low-, moderate-, high- and very high-hazard zones. Resulted landslide hazard zonation map was further validated with field study and geospatial technology-based analysis. The findings demonstrate high-landslide-hazard zones are associated with areas of active erosive processes (steep slopes/cut slopes/lineaments). The results indicate the villages Bomtar, Jorethang, Kopchey, Donok, Namthang, Sumbuk, Longchok, Mamring, Turung, Mikkhola, etc. are highly prone to landslides. The final landslide hazard zonation map can be used for the landslide hazard prevention, proper planning of future infrastructure and geoenvironmental development in Namchi region.

Landslide Hazard Zonation and Slope Instability Assessment using Optical and InSAR Data: A Case Study from Gidole Town and its Surrounding Areas, Southern Ethiopia

The present study was carried out in and around Gidole Town in Southern Ethiopia which is about 580km from Addis Ababa. The main objective of the study was to prepare a landslide hazard zonation (LHZ) map by using Bivariat statistical information value model and to assess the slope instability in the area by using InSAR approach. For LHZ six causative factors such as; slope, land-use/land-cover, slope-material, elevation, aspect, and Normalized Difference Vegetation Index (NDVI) were considered. For the sub-classes of these causative factors weights were obtained from the information value model. The results showed that very high hazard zones and high hazard zones covers 6.63% (14.12 km2) and 15.36% (32.72 km2) of the area, respectively. Whereas, moderate hazard, low hazard and very low hazard zones covers 7.47% (15.9 km2), 34.2% (72.85 km2) and 36.34% (77.4 km2) of the area, respectively. Further, validation of the LHZ map showed that 92.3% of the past landslides fall in very high hazard and high hazard zones. Thus, the hazard zones delineated in the present study has reasonably validated with the past landslide data and the potential zones depicted in the prepared LHZ map can be applied for the safe planning of the area. Further, the results of the PS-InSAR processing indicates that the average downward displacement in the study area is gradually increasing from 15.3mm/yr (2014) to −19.2 mm/yr (2018) and the rate of displacement in general increases with increase in the average monthly precipitation at all selected persistence scattered points.

LANDSLIDE HAZARD ZONATION IN AND AROUND KEDARNATH REGION AND ITS VALIDATION BASED ON REAL TIME KEDARNATH DISASTER USING GEOSPATIAL TECHNIQUES

Abstract. Landslides are one of the frequently happening disasters in this hilly state of Uttarakhand which accounts to the loss of lives and property every year especially during the rainy season which lead to affect the families. With the development of satellite observation technique, advanced data analysis tool and new modeling techniques landslide hazard zonation map can be prepared.In the present study, Landslide Hazard Zonation (LHZ) for Kedarnath to Augustmuni region of Rudraprayag district of Uttarakhand state was carried out using Remote Sensing and GIS technique. For the preparation of LHZ map, year 2010 high resolution satellite data have been used. After preprocessing of the data various thematic layers are prepared in GIS environment. The weighted-rating system technique were used for the LHZ map showing the five zones, namely “very low hazard”, “low hazard”, “moderate hazard”, “high hazard” and “very high hazard” . This map has been validated after the tragedy of Kedarnath in Uttarakhand, Total no. of 224 Landslides has been marked from Kedarnath to Augustmuni region just after the kedarnath tragedy in year 2013. When this landslides thematic layer is overlaid on LHZ, the study shows that approximately 50% landslides was there where in LHZ map high and very high hazard zones have been identified. After the tragedy our team workers have gone to the field, with the help of DGPS around 40 ground control points have been taken to validate our result. So by using this geospatial technique around 50% people’s life can be saved.

LANDSLIDE HAZARD ZONATION MAPPING OF CHAMOLI LANDSLIDES IN REMOTE SENSING AND GIS ENVIRONMENT

Abstract. Landslides are very common problem in hilly terrain. Chamoli region of Himalaya is highest sensitive zone of the landslide hazards. The purpose of Chamoli landslide study, to observe the important terrain factors and parameters responsible for landslide initiation. Lithological, geomorphological, slope, aspect, landslide, drainage density and lineament density map generated in remote sensing and GIS environment. Data information of related geological terrain obtain through topographic maps, remote sensing images, field visits and geological maps. Geodatabases of all thematic layers prepared through digitization of topographic map and satellite imageries (LISS-III, LISS-IV & ASTER DEM). Integrated all thematic layers applying information value method under GIS environment to map the zonation of landslide hazard zonation map validation and verification completed by field visit. The landslide hazard zonation map classified in four classes very high, high, medium and low.

Assessment of density area and LNRF models in landslide hazard zonation (Case study: Alamout watershed, Qazvin Province, Iran)

Landslide is one of the natural disasters causing both life loss and financial damage. To plan and manage landslides better, it is necessary to produce landslide hazard zonation (LHZ) maps. Alamout watershed is one of the most susceptible landslides located in a mountainous area in north of Iran. At first, required information of layers such as geology, soil, elevation, slope, aspect, rainfall, and distance to fault, road, river, and land use factors from different sources were provided. Landslide inventory map was prepared using geological map, aerial photos and filed investigation with GPS. The map of each effective factor on the landslide was combined with the landslide distribution map to determine the weight of each factor. Landslide hazard zonation map was prepared with density area and LNRF methods in the Geographic Information System (GIS). The two models were evaluated with quality sum (Qs). Results showed that the density area method (Qs= 1.496) was more accurate than the LNRF model (Qs= 0.897). The results obtained from density area model indicated that very high hazard zones were approximately 33% of the study area. Additionally, low and very low hazard zones were almost 6.8% of the watershed. In the LNRF model, very low and low hazard zones were approximately 28% and high and very high hazard zones were 48% of the studying region.

Mapping sand and clay-filled depressions on a coastal chalk clifftop using gravity and seismic tomography refraction for landslide hazard assessment, in Normandy, France

In this study, we present a complete and successful case study where gravity and seismic refraction surveys detect and map previously poorly known sand and clay-filled depressions within the top chalk layers in a costal context, near Dieppe, Normandy, France. This study was commissioned by local authorities after a coastal chalk cliff collapse exposed a sand and clay-filled depression which turned into a > 100,000 m3 landslide. This resulted in a massive clifftop retreat exceeding 40 m, which threatened infrastructure and amenities. For risk and safety assessment, coastal managers commissioned BRGM to (i) determine the depth and extent of the sand and clay-filled depression, and (ii) map the presence of similar cliff-top depressions in a 2-km-long and 400-m-wide band inland of the coast. Both geophysical methods allow the detection and mapping of the sand and clay-filled depressions, which are characterised by a co-localized deepening of the first seismic horizon and a positive gravity anomaly. Seven auger holes confirm the geophysical interpretation, with depth to the top of the chalk >60 m in some instances. A map of the depth to the top of chalk is inverted using the gravity residuals.The successful mapping of the previously poorly-documented sand and clay-filled depressions on the Dieppe clifftop, using both gravity and seismic refraction tomography, was used in part to generate a Coastal Landslide Hazard Zonation map, which is a useful tool for coastal managers who need to make hazard-mitigating decisions.

Landslide hazard zonation using analytical hierarchy process along National Highway-3 in mid Himalayas of Himachal Pradesh, India

Landslide zonation studies emphasize on preparation of landslide hazard zonation maps considering major instability factors contributing to occurrence of landslides. This paper deals with geographic information system-based landslide hazard zonation in mid Himalayas of Himachal Pradesh from Mandi to Kullu by considering nine relevant instability factors to develop the hazard zonation map. Analytical hierarchy process was applied to assign relative weightages over all ranges of instability factors of the slopes in study area. To generate landslide hazard zonation map, layers in geographic information system were created corresponding to each instability factor. An inventory of existing major landslides in the study area was prepared and combined with the landslide hazard zonation map for validation purpose. The validation of the model was made using area under curve technique and reveals good agreement between the produced hazard map and previous landslide inventory with prediction accuracy of 79.08%. The landslide hazard zonation map was classified by natural break classifier into very low hazard, low hazard, moderate hazard, high hazard and very high landslide hazard classes in geographic information system depending upon the frequency of occurrence of landslides in each class. The resultant hazard zonation map shows that 14.30% of the area lies in very high hazard zone followed by 15.97% in high hazard zone. The proposed model provides the best-fit classification using hierarchical approach for the causative factors of landslides having complex structure. The developed hazard zonation map is useful for landslide preparedness, land-use planning, and social-economic and sustainable development of the region.

Landslide Hazard Zonation (LHZ) Mapping Using RS and GIS Techniques: A Case Study of Kumbur River Basin of Kodaikanal Taluk, Dindigul District, Tamilnadu, India

Landslide Hazard Zonation (LHZ) Mapping Using RS and GIS Techniques: A Case Study of Kumbur River Basin of Kodaikanal Taluk, Dindigul District, Tamilnadu, India

Landslide Susceptibility Zonation Mapping in Post- Earthquake Scenario in Gorkha District

Landslide hazard zonation map is prepared to assist planners to implement mitigation measures so that further damage and loss can be minimized. In this study, post 25 April 2015 earthquake remote sensing data were used to prepare landslide inventory. Landsat images after the earthquake were downloaded from the National Aeronautics and Space Administration (NASA) website and processed using ArcGIS, ERDAS imagine and Analytical Hierarchy Process (AHP) as an extension in ArcGIS. The study was carried out in Gorkha district as this was the epicenter of the main earthquake of 25 April 2015 and consequently was highly affected by earthquake triggered landslide. The digital imagery was processed to analyze land use/land cover type. Geological features were analyzed using the criteria like color, tone, topography, stream drainage, etc. Primary topographic features like slope, aspect, elevation, etc. were generated from Digital Elevation Model (DEM). Seismological data (magnitude and epicenter) were obtained from Department of Seismology. For Landslide Susceptibility Zonation (LSZ) different thematic maps like Land Use and Land Cover (LULC) map, slope map, aspect map, lithological map, buffer map (distance from road and river/water source), soil map, and seismological map were assigned relative weights on the ordinal scale to obtain Landslide Susceptibility Index (LSI). Threshold values were selected according to breaks in LSI frequency and a LSZ map was prepared which shows very low, low, moderate, high, very high hazard zones in Gorkha district.

Hazard assessment of landslide disaster using information value method and analytical hierarchy process in highly tectonic Chamba region in bosom of Himalaya

The present study is focused on a comparative evaluation of landslide disaster using analytical hierarchy process and information value method for hazard assessment in highly tectonic Chamba region in bosom of Himalaya. During study, the information about the causative factors was generated and the landslide hazard zonation maps were delineated using Information Value Method (IV) and Analytical Hierarchy Process (AHP) using ArcGIS (ESRI). For this purpose, the study area was selected in a part of Ravi river catchment along one of the landslide prone Chamba to Bharmour road corridor of National Highway (NH-154A) in Himachal Pradesh, India. A numeral landslide triggering geoenvironmental factors i.e. slope, aspect, relative relief, soil, curvature, land use and land cover (LULC), lithology, drainage density, and lineament density were selected for landslide hazard mapping based on landslide inventory. Landslide hazard zonation map was categorized namely “very high hazard, high hazard, medium hazard, low hazard, and very low hazard”. The results from these two methods were validated using Area Under Curve (AUC) plots. It is found that hazard zonation map prepared using information value method and analytical hierarchy process methods possess the prediction rate of 78.87% and 75.42%, respectively. Hence, landslide hazard zonation map obtained using information value method is proposed to be more useful for the study area. These final hazard zonation maps can be used by various stakeholders like engineers and administrators for proper maintenance and smooth traffic flow between Chamba and Bharmour cities, which is the only route connecting these tourist places.

Fuzzy logic approach for landslide hazard zonation mapping using GIS: a case study of Nilgiris

Landslides are one of the common natural as well as man-made hazards in mountainous terrain which causes huge damage to human beings and property. In this paper mapping of landslide hazardous zones based on fuzzy logic approach using GIS techniques. In this regard various landslide parameters were generated which related to landslide occurrences in Coonoor and Kothagiri taluks. The fuzzy membership value is assigned on individual parameters such as active–passive slope, concave-plain-convex slope, drainage density, dissected-un dissected slope, geology, geomorphology, lineament density, lineament frequency, lineament intersection density, landuse/land cover, rainfall, degree of weathering /regolith cover, shallow-moderate-steep slope, soil, and water level. An attempt is made to integrate these parameters on different fuzzy operators and produce landslide hazard zonation map and its divides the study area into three zones viz., high, moderate and low. 95% of the existing landslides have been observed in high hazard class. The final map is validated using area under curve method for calculating prediction accuracy.

Landslide hazard mapping along national highway-154A in Himachal Pradesh, India using information value and frequency ratio

For the socio-economic development of a country, the highway network plays a pivotal role. It has therefore become an imperative to have landslide hazard assessment along these roads to provide safety. The current study presents landslide hazard zonation maps, based on the information value method and frequency ratio method using GIS on 1:50,000 scale by generating the information about the landslide influencing factors. The study was carried out in the year 2017 on a part of Ravi river catchment along one of the landslide-prone Chamba to Bharmour road corridor of NH-154A in Himachal Pradesh, India. A number of landslide triggering geo-environmental factors like “slope, aspect, relative relief, soil, curvature, Land Use and Land Cover (LULC), lithology, drainage density, and lineament density” were selected for landslide hazard mapping based on landslide inventory. The landslide inventory has been developed using satellite imagery, Google earth and by doing exhaustive field surveys. A digital elevation model was used to generate slope gradient, slope aspect, curvature, and relative relief map of the study area. The other information, i.e., soil maps, geological maps, and toposheets, have been collected from various departments. The landslide hazard zonation map was categorized namely “very high hazard, high hazard, medium hazard, low hazard, and very low hazard.” The results from these two methods have been validated using area under curve (AUC) method. It has been found that hazard zonation map prepared using frequency ratio model had a prediction rate of 75.37% while map prepared using information value method had prediction rate of 78.87%. Hence, on the basis of prediction rate, the landslide hazard zonation map, obtained using information value method, was experienced to be more suitable for the study area.

GIS based mapping and analysis of landslide hazard’s impact on tourism: a case study of Balakot valley, Pakistan

The Landslide occurs in mountainous area due to failure of slope through intensive rain and earthquake. Region wise Himalayan is one of prone area of world in context of slope failure hazard; i.e. Landslide, especially Balakot valley is well known for damage of public infrastructure, roads and badly affected the tourism sector. The objective of this study is to develop landslide hazard map and database inventory of balakot tehsil and identify the Tourist resorts landslide hazard condition and hazard prone road site and developed guidelines for tourist about hazardous site and their intensity of landside, which could be useful for tourism sector and sustainable development in balakot valley. In this study we used weighted overlay analysis in arc GIS environment on primary and secondary data raster layers, like slope map, Slope Aspect map, precipitation and seismic raster maps were used to develop landslide hazard zonation map of balakot tehsil. Slope and Aspect map were developed using 30 meter aster digital elevation model. Precipitation map were developed through Inverse Distance weighted (IDW) interpolation method on annual precipitation data acquired from Pakistan meteorological department. Seismic map were acquired from Geological Survey of Pakistan (GSP). Landslide zonation map has three hazards class high, Medium and low. The landslide exposure of high hazard class 499 sq.km while, Medium class 1016 sq.km and low hazard class having 749 sq. km exposure in balakot tehsil respectively. Landslide hazard zonation mapping using GIS and RS is the best way to assess the risk of landslide hazard in mountainous areas. The study recommended that ground penetrating radar (GPR) and soil testing based research well help to understand in-depth of landslide hazard condition in balakot valley.

Landslide hazard evaluation and zonation in and around Gimbi town, western Ethiopia—a GIS-based statistical approach

The main purpose of the present study was to carry out landslide evaluation and zonation in and around Gimbi town in western Ethiopia, located about 440 km from Addis Ababa. This study was conducted following GIS-based statistical method. For hazard evaluation and zonation, nine causative factors viz., slope material, elevation, slope, aspect, curvature, groundwater surface traces, distance to roads, and distance to streams were considered. Data on these causative factors were obtained from secondary maps, digital elevation model, topographical sheets, and through field mapping. Fifty past landslides in the study area were also identified and mapped through field survey and image interpretation. Statistical correlations between each of the causative factors and the past landslides were established in GIS environment to rate the relative contribution of individual factor classes. Thus, by considering ratings for each causative factor subclasses and by assigning suitable weights to each factor, random trial combinations were attempted to produce the landslide hazard zonation map. The results showed that 12.2% of the study area falls in very high hazard, 30.7% in high hazard, 24.3% in moderate hazard, 23.3% in low hazard, and the remaining 9.5% in no hazard zones. Validation of landslide hazard zonation map with past landslides showed that 75% of the past landslides fall within very high and high hazard zones. Thus, the hazard zones depicted can be considered for future planning and development of the study area.

Landslide Hazard Zonation Map of Joshimath- Badrinath Region, India: Using Remote Sensing and GIS Technique

Landslide Hazard Zonation Map of Joshimath- Badrinath Region, India: Using Remote Sensing and GIS Technique

Landslide hazard zonation mapping on meso-scale in SH-37 ghat section, Nadugani, Gudalur, the Nilgiris, India

Landslide is the most common natural disaster in mountainous regions. It causes damages to life and properties. The study area, Calicut–Nilampur–Gudalurghat section (SH37) falls under the Survey of India toposheet 58A-7/NE (1:25,000). The present study was carried out with landslide hazard zonation mapping on meso-scale. This paper explains how meso-zonation of landslide hazards (facet-wise) was made from investigations as per the norms given in Bureau of Indian Standard IS 14496:1998. Remote sensing and geographic information system (GIS) was utilized for the preparation of thematic maps on 1:10,000 scale. The present study evaluates more detailed related factors of inherent causative factors (lithology, structure, slope gradient, relative relief, land use/land cover, and hydrogeology) involved in landslides. This method also incorporates effects of external causative factors like seismicity and rainfall as corrected rating. In the study area, 10 different facets have been identified. This area falling in facets 3, 4, 6, 7, and 10 come under high hazardous zone, the slopes falling in the facets 1 and 5 fall in the moderate hazardous zone, facet 2 in low hazard zone and other facets 8 and 9 show very high hazardous zone. Details of this work are presented in this paper. The landslide inventory points were collected with the help GPS in this ghat section. The inventory percentage 3.3% comes in low hazard zone, 18% present in moderate hazard zone, 57.4% in high hazard zone, and 21.3% under very high hazard zone.

Social Geology and Landslide Disaster Risk Reduction in Sri Lanka

Landslide disaster risk reduction is presently a challenging task facing by Sri Lankangeologists. Increasing trend of population growth in Sri Lanka has adversely affected thestability of central highland due to various human activities. Among them establishment ofhuman settlements and change in land use pattern have become a serious issue in triggeringland instabilities in central highland of the country. National Building Research Oragnisationwhich is the main focal point in land slide disaster risk reduction in Sri Lanka has takenvaluable and timely needed actions including preparation of landslide hazard zonation maps,early warnings and mitigations. Though the landslide is a geological phenomenon, it is highlyinteracted with human societies. Hence managing the issues arising with the landslideoccurrence should be addressed with a sociological approach. This new approach is known asSocio Geological approach which is discussed here.Key words: Landslide, Geology, Socio Geology, Social Geologist