Causes Of Landslides Research Articles

Landslide Susceptibility Analysis (LSA) using Deterministic Model (Infinite Slope) (DESSISM) in the Kota Kinabalu Area, Sabah, Malaysia

A practical application for landslide susceptibility analysis (LSA) based on two dimensional deterministic slope stability (infinite slope model) (DESSISM) was used to calculate factor of safety (FOS) and failure probabilities for the area of Kota Kinabalu, Sabah. LSA is defined as quantitative or qualitative assessment of the classification, volume (or area) and spatial distribution of landslides which exist or potentially may occur in an area. In this paper, LSA value can be expressed by a FOS, which is the ratio between the forces that make the slope fail and those that prevent the slope from failing. An geotechnical engineering properties data base has been developed on the basis of a series of parameter maps such as effective cohesion (C’), unit weight of soil ,)?(depth of failure surface (Z), height of ground water table (Zw), Zw/Z dimensionless (m), unit weight of water ,)w?(slope surface inclination (s) and effective angle of shearing resistance (?). Taking into consideration the cause of the landslide, identified as groundwater change, the maximum groundwater level recorded corresponding to the actual situation of the most recent landslide is considered in this study. The highest probability value of the various scenarios was selected for each pixel and final LSA map were constructed. It has been found from this study that s and Zw parameters have the higher influence on landslide instability. The result validation between the examined LSA map and result of landslide distribution map (LDM) were evaluated. This DESSISM had higher prediction accuracy. The prediction accuracy is 84%. The resulting LSA maps can be used by local administration or developers to locate areas prone to landslide area, determine the land use suitability area and to organize more detailed analysis in the identified “hot spot” areas.

Numerical Analysis of Ground Motion Effects in the Loess Regions of Western China

Loess is widely distributed in the western part of China and its area comprises 6.6% of Chinese territory. Because of the characteristics of high porosity, low strength, and weak cementation, the loess is characterized by high seismic vulnerability which has been observed and confirmed by many researchers at home and abroad. The postquake field investigation and the laboratory study have shown that the ground motion effects, including the amplification effects and slope effects, were obvious in loess sites. Moreover, the causes of landslides, seismic subsidence, and liquefaction were mainly attributed to this special soil structure and properties. In this paper, based on the data of shear wave velocity of typical loess in Lanzhou region, combining the results of dynamic triaxial tests, the numerical analysis of ground motion effects in the loess regions is analyzed. The results reveal how the ground motion effects are checked and demonstrated the important role of numerical simulations while studying the characteristics of ground motions.

Landslide investigations in Russia and the former USSR

Landslide hazard has always been a focus of research of scientific and industrial organizations in Russia, as well as the former Soviet Union . This research included a broad spectrum of studies of landslide processes based on monitoring data collected at specialized stations nationwide, as well as the data collected and analyzed by various government and academic research institutions. The current study summarizes a vast body of knowledge encompassing an inventory of landslide cases, overview of mechanisms of landslide development and monitoring and slope stability assessments. It presents a new mechanism-based landslide classification and proposes a practical method of increasing slope resistance. Partial findings have been previously presented in numerous publications. We believe these findings have a worldwide significance and can be applied in different regions of our planet.

Effects of image orientation and ground control points distribution on unmanned aerial vehicle photogrammetry projects on a road cut slope

The morphology of road cut slopes, such as length and high slopes, is one of the most prevalent causes of landslides and terrain stability troubles. Digital elevation models (DEMs) and orthoimages are used for land management purposes. Two flights with different orientations with respect to the target surface were planned, and four photogrammetric projects were carried out during these flights to study the image orientation effects. Orthogonal images oriented to the cut slope with only sidelaps were compared to the classical vertical orientation, with sidelapping, endlapping, and both types of overlapping simultaneously. DEM and orthoimages obtained from the orthogonal project showed smaller errors than those obtained from the other three photogrammetric projects, with the first one being much easier to manage. One additional flight and six photogrammetric projects were used to establish an objective criterion to locate the three ground control points for georeferencing and rectification DEMs and orthoimages. All possible sources of errors were evaluated in the DEMs and orthoimages.

Progressive Failure Behavior and Mechanism of Soil Slopes under Dynamic Loading Conditions

AbstractDynamic loading is a major cause of landslides with significantly different behavior from static loading. A series of centrifuge model tests was conducted to investigate the progressive failure behavior of slopes under dynamic loading conditions, with a focus on the effect of cyclic loading. The cyclic effect induced significant deformation and final failure of the slope, which was influenced by the cyclic loading patterns. The slip surface developed from the top of the slope downward to the lower part with the application of vertical loading. The failure process of the slope exhibited a significant coupling with the deformation localization under dynamic loading conditions. The deformation localization developed in the slope during loading and resulted in the formation of the slip surface. Alternately, the local failure caused stronger deformation localization near the slip surface. The deformation was mainly concentrated in a limited zone. In the zone, a reversed triangular zone under the loadin...

Optimal Subdivision for Treatment and Management of Catastrophic Landslides in a Watershed Using Topographic Factors.

Recent extreme rainfall events led to many landslides due to climate changes in Taiwan. How to effectively promote post-disaster treatment and/or management works in a watershed/drainage basin is a crucial issue. Regarding the processes of watershed treatment and/or management works, disaster hotspot scanning and treatment priority setup should be carried out in advance. A scanning method using landslide ratio to determine the appropriate outlet of an interested watershed, and an optimal subdivision system with better homogeneity and accuracy in landslide ratio estimation were developed to help efficient executions of treatment and/or management works. Topography is a key factor affecting watershed landslide ratio. Considering the complexity and uncertainty of the natural phenomenon, multivariate analysis was applied to understand the relationship between topographic factors and landslide ratio in the interested watershed. The concept of species-area curve, which is usually adopted at on-site vegetation investigation to determinate the suitable quadrate size, was used to derive the optimal threshold in subdivisions. Results show that three main component axes including factors of scale, network and shape extracted from Digital Terrain Model coupled with areas of landslide can effectively explain the characteristics of landslide ratio in the interested watershed, and a relation curve obtained from the accuracy of landslide ratio classification and number of subdivisions could be established to derive optimal subdivision of the watershed. The subdivision method promoted in this study could be further used for priority rank and benefit assessment of landslide treatment in a watershed.

Procedure and results of seismic investigations into causes of landslides in permafrost rocks

The article focuses on seismic monitoring of causes of landslides. Such studies are of great importance in open pit mining in permafrost rocks. Extensive mining-induced impact in combination with natural thawing of permafrost as a consequence of the planet warming may end in catastrophe. The authors describe a procedure for plotting velocity profiles of seismic waves along slopes in the presence of extremely contrast discontinuities conditioned by permafrost rocks. The presented approach enables studying slip surfaces of landslides and detecting potential failure zones where wave velocities are lower due to extensive jointing. The processed field data obtained in the area near Chagan-Uzun settlement in Kosh-Agach district of the Republic of Altai are reported.

Landslide Prediction with Rainfall Analysis using Support Vector Machine

Objective: The paper aims in presenting a prediction model by using Support Vector Machine (SVM) technique which is meant to possess a strong capability to predict landslides by forecasting rainfall dataset using BigData concept. Methods: The dataset has been taken for the Cherapunjee region which receives the highest intensity of rainfall in India. The aim is to predict the landslide occurrence and classify the risk level associated with the landslide. To improve the reliability in landslide prediction, the proposed model uses pre-processing for removing null values in the dataset. After getting the pre-processed dataset, it will apply normalization, then SVM training and finally the Testing process. Thus the Support Vector Machine concept proved to exhibit a large degree of flexibility in handling tasks of varied complexities because of the non-linear boundary functions. Findings: The study concludes that SVM proved to be an efficient technique to forecast the landslides by predicting the rainfall in advance. The comparative results of SVM in regard with Artificial Neural Networks were proven. The study has been done specifically for Cherrapunjee region and can be implemented for any landslide prone area. Novelty/Improvement: Researchers worldwide are having a great pace to develop early prediction mechanisms for natural hazards. The study uses Radial Basis Function as an initial parameter for predicting the risk level classification of landslide. The novelty is in providing an initial selection of the kernel parameter in order to save the time on finding the best parameters.

Возможности прогноза активности оползневых явлений по результатам индуктивного моделирования и дистанционных методов исследований

The object of study: Landslide processes developing in the Dnepropetrovskcity. Objective: to substantiate the accuracy of the existing classification of landslides in the Dnepropetrovsk city in order to develop methods of prediction landslide activity of remote research. Research Method: cartographic modeling, mathematical modeling, which includes the primary statistic, correlation, clustering, regression types of stochastic analysis and inductive modeling (group method of data). It was found that the solution of the research and prediction of landslides activation is impossible without an integrated approach to the study and analysis of landslide processes. The best results in the solution of this problem can be obtained by the monitoring of geological environment with using remote sensing (RS). In this work, the forecast of landslide activity methods of inductive modeling (group method of data) on the basis of a joint analysis results of monitoring the geological environment of Dnepropetrovsk, Dneprodzerzhinsk agglomeration (1983 – 2006. «Ukryuzhgeologiya») and are available free of remote sensing satellites LANLΛSAT 5 and LANLΛSAT .Keywords: landslide, remote sensing, group method of data, forecast

Semiautomated object-based classification of rain-induced landslides with VHR multispectral images on Madeira Island

Abstract. A method for semiautomated landslide detection and mapping, with the ability to separate source and run-out areas, is presented in this paper. It combines object-based image analysis and a support vector machine classifier and is tested using a GeoEye-1 multispectral image, sensed 3 days after a major damaging landslide event that occurred on Madeira Island (20 February 2010), and a pre-event lidar digital terrain model. The testing is developed in a 15 km2 wide study area, where 95 % of the number of landslides scars are detected by this supervised approach. The classifier presents a good performance in the delineation of the overall landslide area, with commission errors below 26 % and omission errors below 24 %. In addition, fair results are achieved in the separation of the source from the run-out landslide areas, although in less illuminated slopes this discrimination is less effective than in sunnier, east-facing slopes.

Data Fusion Technique Using Wavelet Transform and Taguchi Methods for Automatic Landslide Detection From Airborne Laser Scanning Data and QuickBird Satellite Imagery

Landslide mapping is indispensable for efficient land use management and planning. Landslide inventory maps must be produced for various purposes, such as to record the landslide magnitude in an area and to examine the distribution, types, and forms of slope failures. The use of this information enables the study of landslide susceptibility, hazard, and risk, as well as of the evolution of landscapes affected by landslides. In tropical countries, precipitation during the monsoon season triggers hundreds of landslides in mountainous regions. The preparation of a landslide inventory in such regions is a challenging task because of rapid vegetation growth. Thus, enhancing the proficiency of landslide mapping using remote sensing skills is a vital task. Various techniques have been examined by researchers. This study uses a robust data fusion technique that integrates high-resolution airborne laser scanning data (LiDAR) with high-resolution QuickBird satellite imagery (2.6-m spatial resolution) to identify landslide locations in Bukit Antarabangsa, Ulu Klang, Malaysia. This idea is applied for the first time to identify landslide locations in an urban environment in tropical areas. A wavelet transform technique was employed to achieve data fusion between LiDAR and QuickBird imagery. An object-oriented classification method was used to differentiate the landslide locations from other land use/covers. The Taguchi technique was employed to optimize the segmentation parameters, whereas the rule-based technique was used for object-based classification. In addition, to assess the impact of fusion in classification and landslide analysis, the rule-based classification method was also applied on original QuickBird data which have not been fused. Landslide locations were detected, and the confusion matrix was used to examine the proficiency and reliability of the results. The achieved overall accuracy and kappa coefficient were 90.06% and 0.84, respectively, for fused data. Moreover, the acquired producer and user accuracies for landslide class were 95.86% and 95.32%, respectively. Results of the accuracy assessment for QuickBird data before fusion showed 65.65% and 0.59 for overall accuracy and kappa coefficient, respectively. It revealed that fusion made a significant improvement in classification results. The direction of mass movement was recognized by overlaying the final landslide classification map with LiDAR-derived slope and aspect factors. Results from the tested site in a hilly area showed that the proposed method is easy to implement, accurate, and appropriate for landslide mapping in a tropical country, such as Malaysia.

Analysis and evaluation of stability for the reactivated landslide along deep-seated weakness zones

In areas where landslides have occurred in the past, it is prone to additional landslides because of similar geological and geographical characteristics. A slope sliding by a reactivated landslide can result in accidents, extra cost and delayed construction schedule. Hence, it is important to identify evidence of past landslides during the design and construction phases in these areas. In the study area presented in this paper, tension cracks were found during clearing and grubbing work prior to the construction of cut slopes at a tunnel portal, implying that landslides had occurred in the past. To mitigate risk, slope gradient was decreased to 1:1.3 with removal of tension cracks, however, 90 m-long tension cracks occurred subsequently. Therefore, detailed geotechnical investigations and analysis were carried out. This paper aims to present procedures and results of analysis to clarify causes of landslides, including selection of the optimum countermeasures for stabilization of the cut slope. We hope that this case study will provide useful information to other engineers and contribute to the prevention of disaster caused by landslide.

A Geological Appraisal of Slope Instability in Upper Alaknanda Valley, Uttarakhand Himalaya, India

Landslide is frequently occurring natural phenomenon causing land degradation in mountainous region of the world. The fragile Himalayan terrain of Uttarakhand often faces challenging and tough situation due to landslides, particularly in monsoon season. Change in rainfall pattern, anthropogenic activity, deforestation, construction on old landslide debris and Quaternary deposits and displacement of habitation from hill side to valley side are some significant increasing factors for the landslide susceptibility. Anthropogenic activities include very fast, unscientific and uncontrolled urbanization and these are considerably responsible to carved out the disaster viz., landslide, cloudburst and flash flood. Habitation and infrastructure development initiatives in close proximity of streams and rivers as also over Quaternary deposits and unplanned disposal of excavated rock and debris are observed to aggravate the fury of both, landslides and flash floods in the region. Mostly in monsoon season frequent disruption of road network by landslides cause hardship to tourists and pilgrims along with local people. During monsoon season torrential rainfall and cloudburst events are common which acts as basic factor for triggering the landslides in the area. It is therefore necessary to analyse the causes of landslides so as to suggest viable mitigation measures. The paper outlines slope instability and factors responsible for the landslide susceptibility in upper Alaknanda valley, Uttarakhand, India.

Occurrence of landslides in Nepal and their mitigation options

Landslides are very common occurrences in Nepal that have been affected development infrastructures, lives, and properties of the people every year. Many hill villages are situated on or adjacent to unstable slopes and old landslides are reactivated from time to time. The rapidly increasing construction of infrastructure, such as roads, irrigation canals, and dams without due consideration of natural hazards is contributing to triggering of landslides and debris flows. Thus, this paper has explored the cause and characteristics of landslides occurrences and their mitigation practices in Nepal. Topographic, geologic and triggering factors, and human intervention causing landslides are characterised to suggest the suitable mitigation options that can be implemented in the mountain hill-slopes. Among the wide range of slope stabilisation measures which are available to practitioner engineer, the lowering of groundwater level in combination of controlling of surface infiltration (e.g. sealing of tension cracks) of water into landslide are the most cost effective options for mountainous terrain because the rise in pore water pressure is one of the basic cause of landslides during the rainy season. In addition, removing of unstable slope debris, surface drainage, and retaining walls are the useful landslide mitigation measures depending on site conditions, availability of budget, and specific requirements. Various support systems and elements can be crafted for creative solutions of the slope instability problems in Nepal.

Classification of large-scale landslides induced by the 2008 Wenchuan earthquake, China

Over 30,000 landslides were triggered by the 2008 Wenchuan earthquake. The deformation and failure mechanisms of these landslides have been found distinct from those of general landslides self-weight induced. Under gravity, typical sliding in rock slope commonly occurs along a gentle tension crack in some depth at the rear part, which connects to a shear plane at the lower part of the slope to form a complete failure surface. However, due to seismic shaking, a much deeper and steeper tension crack tends to develop at the rear part, which promotes the shearing at the far lower part of the slope. In this paper, the failure modes of earthquake-induced landslides have been classified into four scenarios, in terms of failure mechanisms, characteristics of geological structures, and development of the sliding surface, i.e., tension-strike slipping, tension-dip layering, tension-shattering, and tension-shearing failures. This is evidenced by field investigations. Detailed field investigations were performed on the deformation and failure characteristics of large-scale and deep-seated landslides induced by the Wenchuan earthquake, among which five typical landslides are introduced in this paper in order to illustrate the classification.

Tectonic control on the development and distribution of large landslides in the Northern Apennines (Italy)

The causes of landslides generally invoked in the Northern Apennines of Italy do not fully explain some observed oriented distributions of large landslides along regional-scale tectonic structures (late orogenic antiforms). The aim of the work is to deeply explore the role of tectonics in controlling the development and arrangement of large landslides. We employed a multidisciplinary approach which took into account geomorphological and geological field data, topographic analysis and deep seismic reflection profiles integrated with previously published apatite fission track cooling ages, shallow geophysical and GPS data. In order to explore these relationships, the Valmozzola area was selected as suitable case study, owing to the presence of clearly expressed relationships between recent extensional faults and related fractures and elements of active landslides. Moreover, in the Valmozzola area contractional tectonics acted to produce rock uplift and thus topographic growth. These processes caused hillslopes to approach their threshold angle, and promoted landslides triggered mainly by climate factors. The geological and geomorphological features characterizing the Valmozzola case study affect the entire study area, as they evolved during the same tectonic and climatic phases that characterized this part of the Northern Apennines. Therefore, the results from the Valmozzola area act as a proxy to constrain the control exerted by tectonics on large landslides across a wider area. The distribution of the large landslides has been controlled by tectonics which determined lines of weakness and failure surfaces (passive role) affecting the slopes. On the other hand, tectonics also caused the topographic growth and over-steepening of the slopes (active role) that promoted the occurrence of large landslides. The distribution of large landslides may, therefore, highlight the existence of tectonic processes and it may be used as an indicator of regional-scale tectonic activity, once the geological and geomorphological framework is well constrained.

Evaluating the Public Perceptions of Landslide Risks in the Himalayan Mandi Town

Landslide experts have developed very detailed landslide hazard maps for different parts of Himalayas in India. These maps indicate the types of damage possible and the probabilities of adverse events. Six categories of risk severity are defined on the maps, ranging from severe risk to very low risk. Based on the existing maps, we selected respondents for a survey, some from areas high in risk and others from low-risk regions. Respondents answered several questions related to landslide risk perception and preparedness. Survey results showed a lack of awareness about the scientific causes of landslides among Mandi residents. Most of the respondents were of the belief that they lived at a safe place. Survey results suggested that many inhabitants did not know that landslide hazard maps existed for their region and most of them were not able to understand them. People overestimated the risks associated with landslides. Consequently, some people were more worried of landslides than was justified by the facts. Another important finding was that since catastrophic landslides are rare events, most of the people were risk averse. These people did not show prevention behaviour, and they were not well prepared for an adverse event. Furthermore, results suggest that respondents’ experiences with landslides were positively related to their perceptions of landslide risk. Thus, findings of the present study comply with the concept of availability heuristic.

The research station “Vaskiny Dachi”, Central Yamal, West Siberia, Russia – a review of 25 years of permafrost studies

The research station Vaskiny Dachi on the Yamal Peninsula was established in 1988. Activities aimed at monitoring of permafrost and related environmental features under a relatively low level of nature disturbances caused by gas field development. Cryogenic processes that may affect the environment and their structures have been of primary interest. Landslides are the most common cryogenic processes in Central Yamal in general and also in the proximity of the station. Field surveys of numerous landslides, analysis of their dependence on climatic parameters and their fluctuations resulted in novel classification of cryogenic landslides based on mechanisms of their development. Dating by radiocarbon and dendrochronology allows the separation of cycles of landslide activation. Cryogenic landslides control the development of other processes, such as thermal erosion, river channel erosion and thermokarst. It also affects topography, vegetation pattern, geochemistry of vegetation, ground water and soils. As a result, permafrost parameters, specifically active layer depth and ground temperature, moisture and ice content in the active layer, depend indirectly on landsliding. Monitoring within the framework of the main programs of the International Permafrost Association, such as Circumarctic Active Layer Monitoring (CALM, since 1993) and Thermal State of Permafrost (TSP, since 2011), play an important role among the research activities. From the collected data one can conclude that ground temperature increased on average by about 1 °C since the 1990s. At the same time, active layer fluctuations do not exactly follow the air temperature changes. Spatial changes in ground temperature are controlled by the redistribution of snow which is resulting from strong winds characteristic for tundra environments and the highly dissected relief of Central Yamal. Temporal variations rather depend on air temperature fluctuations but the rate differs in various landscape (environmental) units. While the spatial distribution of active layer depth depends on lithology and surface covers, temporal fluctuations are controlled by ground temperature, summer air temperature, summer precipitation, and in general may contravene climate warming due to specific combination of all factors.

Multisource Data Fusion and Fisher Criterion-Based Nearest Feature Space Approach to Landslide Classification

In this paper, a novel technique known as the Fisher criterion-based nearest feature space (FCNFS) approach is proposed for supervised classification of multisource images for the purpose of landslide hazard assessment. The method is developed for land cover classification based upon the fusion of remotely sensed images of the same scene collected from multiple sources. This paper presents a framework for data fusion of multisource remotely sensed images, consisting of two approaches: 1) the band generation process(BGP); and 2) the FCNFS classifier. We propose the BGP to create a new set of additional bands that are specifically accommodated to the landslide class and are extracted from the original multisource images. In comparison to the original nearest feature space (NFS) method, the proposed improved FCNFS classifier uses the Fisher criterion of between-class and within-class discrimination to enhance the classifier. In the training phase, the labeled samples are discriminated by the Fisher criterion, which can be treated as a preprocessing step of the NFS method. After completion of the training, the classification results can be obtained from the NFS algorithm. In order for the proposed FCNFS to be effective for multispectral images, a multiple adaptive BGP is introduced to create an additional set of bands specially accommodated to landslide classes. Experimental results show that the proposed BGP/FCNFS framework is suitable for land cover classification in Earth remote sensing and improves the classification accuracy compared to conventional classifiers.

EXAMPLES OF LANSLIDES IN THE FEDERATION OF BOSNIA AND HERZEGOVINA WITH THE ANALYSIS OF THE CAUSES OF THEIR ACTIVATION

<p>Bosnia and Herzegovina is characterized by heterogeneous geological structure, and a high degree of tectonic and the seismic activity as well as various relief and the climatic characteristics and water flows of different gradients. All this reflected on engineering-geological characteristics of the terrain.</p><p>The main causes of landslides' activation are changes in level of underground waters, chopping down of forest, great rainfalls, snow melting, long drought periods, changes in slopes, changes in load of a slope, rock's wastage, uncontrolled diversion of surface waters, earthquakes etc. Researches on landslides are carried out in order to establish the cause of landslide's origin and to find out efficient overhaul measures. Landslide's overhaul success depends not only on established causes of landslide's origin, but also on use of technical measures for stopping that process. Overhaul measures' carrying out is important in protection of the environment.</p><p>This paper presents an analysis of co-action of natural factors and negative anthropogenic effect in a settled area, where landslides appear, by its studying and eliminating of causes we are creating the conditions for a successful stabilization of landslides. The paper shows some characteristic landslides with defining of geomorphologic, geologic, engineer geologic, hydrogeologic and geotechnical characteristics of the terrain.</p>