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The field stress path experienced by a soil element during rain-induced slope failures is reproduced by injecting water in an initially unsaturated specimen under constant total stress conditions. The accumulation of injected moisture near the base of triaxial specimens causes non-uniformity in the specimen leading to progressive failure. A new idea of using a helix shaped filter paper wrapped around the specimen’s periphery to uniformly distribute the injected water is presented. Water injection experiments were conducted and the behavior of specimens with and without the presence of filter paper was compared under constant shear stress. The use of helical filter paper ensured more uniform distribution of injected moisture, and reduced the discrepancy of moisture along specimen’s height by around 50%. Improvement in moisture uniformity of the specimen also reduced the possibilities of progressive failure during water injection experiments. The helical filter paper technique was found to hold a strong potential for the reproduction of rain-induced landslide conditions in laboratory triaxial experiments. [ABSTRACT FROM AUTHOR]

[Display omitted] • A landslide spatial prediction framework considering temporal clustering is proposed. • The proposed framework has better accuracy than the traditional susceptibility methodology. • Differentiation of temporal clusters can account structured temporal variations of landslide. Temporal clustering is an intrinsic nature of landslide occurrences, therefore it should be considered in data-driven landslide spatial prediction (i.e., susceptibility assessment). However, it remains problematic regarding how to determine landslide temporal clusters and how to integrate susceptibility maps derived from different landslide temporal clusters. In this paper, a general framework of landslide spatial prediction model considering the temporal clustering of landslides is proposed. This novel framework first assesses landslide susceptibility separately based on each landslide temporal cluster identified by spatiotemporal clustering analysis and then integrates separate assessments by weighted averaging. In a case study, this general framework is implemented using the stacking network landslide susceptibility assessment method and used in the landslide spatial prediction of the Sanming City and Wenchuan seismic areas. The results show that the proposed framework outperformed traditional susceptibility models that do not consider landslide temporal clustering, and the integration of susceptibility models based on all landslide temporal clusters will promote the performance of landslide spatial prediction because levels of knowledge in long-term spatiotemporal landslide activities are considered. This novel general framework highlights the benefit of considering landslide temporal clustering in landslide spatial prediction and can provide better support for landslide risk management. [ABSTRACT FROM AUTHOR]

Landslides represent a large-deformation process influenced by various factors of uncertainty, such as types of ground motion (GM), randomness of GMs, and spatial variability of soils. The behavior of landslides is profoundly affected, making their assessment and measurement challenging. This paper proposes a computational approach for simulating the large-deformation process of landslides based on three-dimensional (3D) non-ordinary state-based peridynamics (NOSBPD). The analysis results of NOSBPD indicate that the mean runout distance triggered by pulse-like ground motions (PLGMs) is 16% greater than that induced by non-pulse ground motions (NPGMs), suggesting that PLGMs exhibit higher destructiveness. Besides, this paper establishes a runout distance assessment framework by considering the stochastic nature of PLGMs. This framework allows for the evaluation of the specific risk probability of landslides caused by stochastic PLGMs that match the target spectrum specified by codes. By introducing the theory of random fields and implementing a coupled procedure in peridynamics, we conducted a detailed analysis of the impact of spatial heterogeneity on the evolution process and consequences of landslides. Additionally, compared to two-dimensional (2D) analysis, the mean runout distance obtained from 3D analysis increased by 27.5%. This suggests that 2D analysis may underestimate the consequences of landslides. The findings of this study can serve as a scientific foundation for predicting the extent and scope of landslides triggered by near-fault earthquakes. • A computational approach for 3D landslide leveraging NOSBPD features is proposed. • A coupling procedure between random fields and PD is proposed. • A runout distance assessment framework is established to evaluate landslide risk. • Effects by various sources of uncertainty are explored. [ABSTRACT FROM AUTHOR]

Detecting the slow motions of highly elevated landslides in remote mountain areas has always been a problem. This paper takes the Woda landslide along the Jinsha River as an example to monitor landslide movement. Although some parts of the landslide body have been found to have moved in recent years, the timing and magnitude of motion have not been systematically monitored or interpreted. Here, we apply the SBAS time series strategy using 65-scene Sentinel-1A/B satellite InSAR images and study the spatial distribution and temporal behaviour of landslide movements between July 4, 2018, and August 29, 2020. Our research results show that the cumulative deformation on the left side of the landslide body with concentrated deformation was approximately 200 mm during the 2-year observation period. By calculating the relationship between the InSAR time series and the precipitation around the landslide, it is found that the landslide deformation is closely related to precipitation. GNSS technology is also deployed on the landslide mass and effectively complements InSAR technology. Simultaneously, based on the results of field surveys and hydrological data analysing the landslide's spatial deformation characteristics and deformation factors, the landslide deformation can also be inferred to be related to precipitation. [ABSTRACT FROM AUTHOR]

Scientific research on mountain hazards has rapidly expanded knowledge of how and when snow avalanches and landslides can occur. Yet mass wasting events continue to produce deadly disasters and expose millions to extreme risk. Governments and scientists have responded by commissioning studies, creating hazard maps, and managing hazard zones to protect people, property, and infrastructure. Property owners, however, frequently contest and challenge avalanche and landslide hazard zones, indicating a continued need to analyze and understand the social dynamics and political struggles embedded in hazard mitigation. Expanding the limited social science research on mountain hazards, this paper examines hazard zone conflicts during a time when an increasing number of people around the world are at risk in the mountains. The goal of this empirical case study from Juneau, Alaska is to show how various societal forces (political, legal, and economic) shape risk and vulnerability at three crucial stages of hazard management: (1) hazard mapping, (2) zoning regulations, and (3) disaster prevention engineering projects. This research demonstrates how hazard mitigation involves a host of intertwined socio-political processes and actors—from experts producing studies and delineating risk zones to city officials and hazard zone property owners redefining those maps, zones, and projects. The paper therefore recommends that scientists and decisionmakers proactively integrate research on local social dynamics into their risk studies to better understand how people might influence the trajectory of hazard management. [ABSTRACT FROM AUTHOR]

Developing a robust numerical method to model earthquake-induced landslides has long been a persistent challenge in the field of computational geotechnical engineering. Recently, the meshless methods based on nonlocal theory have piqued the interest of researchers. However, the application of nonlocal theory in seismic analysis is currently limited. This paper proposed a numerical framework based on the updated Lagrangian nonlocal general particle dynamics (UL-NGPD) method to analyze earthquake-induced landslide problems. The UL-NGPD method benefiting from the update support domain can capture the whole process of slope run-out induced by earthquakes. To enhance the numerical stability of the proposed method, several optimizing strategies are proposed. In the current framework, the seismic waves are input through the proposed boundary treatments of nonlocal form. Besides, a nonlocal friction model with velocity-weakening is proposed to accurately simulate the movement process of soils on a rocky sliding bed. The proposed framework is validated by the simulations of several classic problems, including the collapse of sand and the shake table test. The performance of the proposed approach is further demonstrated through simulating the landslides induced by earthquakes. The numerical results consistent with recorded data indicate that the UL-NGPD method has an excellent capacity to deal with earthquake-induced landslide problems. • A novel nonlocal theory-based UL-NGPD framework is established to analyze earthquake-induced landslides. • The boundary treatments in the UL-NGPD are introduced. • A nonlocal friction model with velocity-weakening is proposed to accurately simulate the movement process of soils. • Several numerical examples demonstrate the UL-NGPD framework's capability in handling complex landslide problems. [ABSTRACT FROM AUTHOR]

To analyze the hazard-causing modes of landslides, this paper proposes a three-dimensional discrete element model reconstruction method that employs an unmanned aerial vehicle survey and multi-electrode resistivity tomography method. To convert the resistivity profile into a material profile, we adopt the peak of the probability density method for material classification and utilize the Haar wavelet transform for image denoising. Subsequently, inverse distance weighting interpolation and the curtain-point method are used to transform two-dimensional profiles into a 3D visualization model. Similarly, the triangular mesh boundary can be extracted from the 3D visualization model using the curtain-point method. A mapping function f including the macroscopic parameters, was defined to populate the particles within the boundaries. Using the iterative method and defining the loss function L for parameter calibration, the targeted 3D discrete element model was constructed after setting the velocity threshold. This method was applied to the Changhe landslide (September 14, 2019) in Gansu Province, China, which had a typical damaged soil layer due to earthquake and rainfall factors. The results indicate that the lower part first exhibits significant displacement, followed by the upper and middle parts, which is consistent with the on-site inspections and UAV findings. • Peak of probability density method for material threshold division of resistivity is proposed. • Using weak attribute inheritance method to define boundary particle attributes. • Given a complete modeling process for discrete elements. • Apply the method to practical applications and verify the results. [ABSTRACT FROM AUTHOR]

This paper mainly explores the deformation instability mechanism and influencing factors of landslide in a town called Fa'er, in southwestern China's Guizhou Province. Drawing on the theories of engineering geological mechanics, the exploration was carried out through the analysis of geological data, field investigation, and drone survey. The results show that: The mining of underground coal seams led to multiple tensile cracks on the trailing edge; the fragmented rock and soil mass, as well as the free face on the front edge create a favorable landform for initiating the landslide; the landslide is mainly induced by the heavy rainfall for several consecutive days; under the continuous heavy rainfall, the creep shear zone was penetrated by cracks, and the landslide was pulled by gravity to slide; the deformation mode shifted from creeping-tensile cracking to plastic flow-tensile cracking. [ABSTRACT FROM AUTHOR]

Over the last few decades, many landslide classification systems have been developed. Inconsistencies across these systems have inevitably led to ambiguity, confusion, and contradictions. Specifically, there has been no consensus on what types of slope movements and failures constitute landslides. As a result, landslide classification systems based on the same criteria do not always include the same types of slope failures. On the other hand, general landslide classification systems do not take into account the unique characteristics of slope failures in loess, which covers about 6.7% of the Earth's land surface. Most literature on loess is in Chinese and the nomenclature, both within the Chinese literature and between the Chinese and English literature, is often not readily comparable. Therefore, there is a need for a consistent and comprehensive system for classification of loess-slope failures to be developed to better manage these particular geohazards as the presence and interactions of humans with the environment in loess areas continue to increase. In this paper, a critical review of landslide classification systems was conducted to identify their limitations, as well as their relevant criteria for classifying loess-slope failures. Understanding the mechanisms underlying the failure of loess slopes is critical for creating a realistic and comprehensive classification system for slope failures. The classification systems of loess-slope failures unified in this paper are based on detailed analyses of the possible mechanisms underlying each class of failure. The primary classification criteria are types of movement and materials, with other descriptive criteria used to explain differences among different classes. For each class, one or two typical case histories are presented. A comprehensive collection of the literature reviewed in this study will facilitate future research on loess geohazards. Unlabelled Image • Landslide classification systems by different criteria are reviewed. • A unified loess landslide classification system with eight key criteria is proposed. • A set of unified nomenclatures for loess landslides are defined. • A framework for study of loess landslides is provided. [ABSTRACT FROM AUTHOR]

Dendrogeomorphology, the dating of geomorphic activity using tree-ring records, is widely employed in forested landscapes impacted by natural hazards, often applied to identify the primary hydrometeorological triggers of such activity. However, the climate background of these papers is frequently imbalanced and necessitates attention and a comprehensive review of the methods and data utilized. This study reviewed 121 papers analysing landslide, debris flow, and snow avalanche reconstructions in conjunction with climate variables. The review assessed the spatial distribution of study sites, uncertainties in dendrogeomorphic and climate data processing, data interpretation, and statistical analysis. While Central Europe, the European Alps, and North American mountain systems have been extensively studied, several regions such as Northern and Southern Europe, the West coast of North America, South Africa, Patagonia, Australia, and New Zealand are still awaiting similar research. Since dendrogeomorphic reconstructions provide information about the year or season of geomorphic activity rather than the specific date, the search for the correct trigger should primarily rely on probability models to identify the most explanatory climate variables. This aspect of landslide dendrogeomorphic research is currently undervalued compared to studies on debris flows and snow avalanches. Moreover, the models should incorporate relevant data, not limited to extreme daily precipitation, but also accounting for antecedent moisture conditions and the snowpack's impact during snowmelt periods. To avoid potential under- or overestimation of extreme precipitation, researchers must ensure the use of appropriate station data that are close in proximity and altitude to the study site, as cautioned by previous discussions. For regional chronologies of geomorphic activity, it is preferable to utilize climate reanalysis products, which are globally available and provide accurate estimations of climate characteristics at various time scales. Consequently, the creation of extensive tree-ring-based datasets encompassing past-to-present geomorphic activity in different regions, along with well-defined climate-geomorphic linkages, will facilitate the modeling of future natural hazard activity under ongoing climate change. [ABSTRACT FROM AUTHOR]

In this paper, we do a critical review of statistical methods for landslide susceptibility modelling and associated terrain zonations. Landslide susceptibility is the likelihood of a landslide occurring in an area depending on local terrain conditions, estimating “where” landslides are likely to occur. Since the first attempts to assess landslide susceptibility in the mid-1970s, hundreds of papers have been published using a variety of approaches and methods in different geological and climatic settings. Here, we critically review the statistically-based landslide susceptibility assessment literature by systematically searching for and then compiling an extensive database of 565 peer-review articles from 1983 to 2016. For each article in the literature database, we noted 31 categories/sub-categories of information including study region/extent, landslide type/number, inventory type and period covered, statistical model used, including variable types, model fit/prediction performance evaluation method, and strategy used to assess the model uncertainty. We present graphical visualisations and discussions of commonalities and differences found as a function of region and time, revealing a significant heterogeneity of thematic data types and scales, modelling approaches, and model evaluation criteria. We found that the range of thematic data types used for susceptibility assessment has not changed significantly with time, and that for a number of studies the geomorphological significance of the thematic data used is poorly justified. We also found that the most common statistical methods for landslide susceptibility modelling include logistic regression, neural network analysis, data-overlay, index-based and weight of evidence analyses, with an increasing preference towards machine learning methods in the recent years. Although an increasing number of studies in recent years have assessed the model performance, in terms of model fit and prediction performance, only a handful of studies have evaluated the model uncertainty. Adopting a Susceptibility Quality Level index, we found that the quality of published models has improved over the years, but top-quality assessments remain rare. We identified a clear geographical bias in susceptibility study locations, with many studies in China, India, Italy and Turkey, and only a few in Africa, South America and Oceania. Based on previous literature reviews, the analysis of the information collected in the literature database, and our own experience on the subject, we provide recommendations for the preparation, evaluation, and use of landslide susceptibility models and associated terrain zonations. [ABSTRACT FROM AUTHOR]

The paper deals with the use of thermography to assess landslide risk. Landslide is a natural process which affects soil. In specific conditions, it can even become cause of death and damages to buildings and structures. Due to climate changes, landslide events have increased in the last years. Sensor networks are today widely used to monitor landslide triggering events. Main problems concern the development costs of such networks, so today attention is principally focused on the use of measurement systems which allow to monitor wide zones at distance. Recently researchers are considering the use of infrared thermography as a promising tool for monitoring landslide process. The paper aims to describe the current potentialities of thermography and its limitations. Several issues and open problems are still to be faced before considering such technique as an effective monitoring tool. For this reason, the author reports the results of a measurement campaign to prove the strengths and weakness of the methodology. Relevant aspects concerning the limits of this measurement technique are described in the following to provide suggestions to users and researchers working in this field. [ABSTRACT FROM AUTHOR]

• Recurrent fire leads to degraded rainforest (DRf) and herbaceous-shrubby (HS). • Ksat and 6 years of rainfall-soil suction interactions are analyzed. • HS provide shallow soil saturation even during long dry periods. • Fire decreases Ksat in topsoil and it increases soil suction in depth at HS. • Post-fire soil changes tend to favor rapid suction loss in the unsatured zone. The role of fire in vegetation-soil–water interactions and its implications for soil stability and slope failures is poorly documented in humid tropical regions. This paper focuses on the relationships between vegetation change through recurrent fire and its effects on hydraulic conductivity and soil suction. Two monitoring sites were chosen on steep slopes in the mountainous domain of the Atlantic rainforest: the first is representative of degraded secondary rainforest (DRf) 25–30 years after slash and burn agriculture; the other represents herbaceous-shrubby vegetation (HS) resulting from wildfires in short-time intervals (<5 years). Two fires had previously occurred on the HS slope, one in December 2014 and the other in September 2019. Continuous records of rainfall and soil suction at depths of 10, 20, 50, 100, 150, and 220 cm provided a 6-year data collection from January 2015 to December 2020. Hydraulic conductivity (Ksat) field tests were conducted around the two monitoring sites before and after the September 2019 fire. The main results include: a) soil suction in the topsoil of both vegetation covers follow the rainfall inputs with high values of Ksat (DRf = 195 mm/h; HS = 203 mm/h); b) while quick rainfall-suction responses prevail within the DRf soil profile, soil suction at HS maintains a mean suction value around -27 kPa below 100 cm deep; c) field observations attest to the occurrence of hydrophobicity after the 2019 fire; d) Ksat tests just after this fire indicated a decreasing mean value from 203 mm/h to 46 mm/h; and e) by the end of the dry season after fire, there is a delayed increase in soil suction reaching -143 kPa at a depth of 100 cm and in smaller proportions at 220 cm deep. These results indicate that post-fire soil changes tend to favor the sudden loss of soil stability and slope failure during extreme rainfall events. [ABSTRACT FROM AUTHOR]

Landslides pose significant risks as natural disasters, highlighting the importance of accurate mapping using remote sensing images for various practical applications. However, due to the challenges arising from incomplete and inaccurate boundary information of foreground landslide polygons, existing methods can only achieve suboptimal performance. To this premise, in this paper, we propose a segmentation network called GMNet that leverages global information extraction and multi-scale feature fusion to enhance the discrimination of landslides from other objects. Specifically, by employing a multi-branch mechanism, our method effectively captures global information, while an improved multi-scale feature fusion technique addresses the issue of varying scales in landslide polygons. Furthermore, semantic enhancement enhances the semantic information of low-level features, bridging the semantic gap and enhancing fusion efficacy. Experimental results demonstrate the effectiveness of our network in segmenting landslide areas accurately within the remote sensing image dataset. Especially, our F1_scores on three benchmarks outperform existing runner-ups by notable margins of 4.81%, 1.72%, and 1.16%, showcasing the value of our method in this domain. • Our method helps to better distinguish landslides from other confusing objects. • Our method effectively addresses the issue of varying resolutions. • Our method improves the fusion effect of different levels of features. • Our method exhibits competitive performance on a landslide segmentation dataset. [ABSTRACT FROM AUTHOR]

The paper deals with the assessment of slope stability on the road II / 595 near the village Zlatno before and after the landslide caused by floods in 2010. For proposal for a comprehensive assessment and possible remedial action is necessary to know the geological conditions and choose the appropriate method for to assess slope stability. The calculation of factor of safety was made using GEO 5 software. The critical factors of safety have been determined by Petterson and Sarma Methods. After finding the most unfavorable slip surface has been made a proposal of remediation measures. The paper presents various solutions to ensure slope stability of the road. The most appropriate remedial action is Variant III - reinforced slope, because he had a greater factor of safety. [ABSTRACT FROM AUTHOR]

The 2008 Wenchuan earthquake triggered the largest number of landslides among the recent strong earthquake events around the world. The loose landslide materials were retained on steep terrains and deep gullies. In the period from 2008 to 2015, numerous debris flows occurred during rainstorms along the Provincial Road 303 (PR303) near the epicentre of the earthquake, causing serious damage to the reconstructed highway. Approximately 5.24 × 10 6 m 3 of debris-flow sediment was deposited shortly after the earthquake. This paper evaluates the evolution of the debris flows that occurred after the Wenchuan earthquake, which helps understand long-term landscape evolution and cascading effects in regions impacted by mega earthquakes. With the aid of a GIS platform combined with field investigations, we continuously tracked movements of the loose deposit materials in all the debris flow gullies along an 18 km reach of PR303 and the characteristics of the regional debris flows during several storms in the past seven years. This paper presents five important aspects of the evolution of debris flows: (1) supply of debris flow materials; (2) triggering rainfall; (3) initiation mechanisms and types of debris flows; (4) runout characteristics; and (5) elevated riverbed due to the deposited materials from the debris flows. The hillslope soil deposits gradually evolved into channel deposits and the solid materials in the channels moved towards the ravine mouth. Accordingly, channelized debris flows became dominant gradually. Due to the decreasing source material volume and changes in debris flow characteristics, the triggering rainfall tends to increase from 30 mm h − 1 in 2008 to 64 mm h − 1 in 2013, and the runout distance tends to decrease over time. The runout materials blocked the river and elevated the riverbed by at least 30 m in parts of the study area. The changes in the post-seismic debris flow activity can be categorized into three stages, i.e., active, unstable, and recession. [ABSTRACT FROM AUTHOR]

The present paper proposes an automatic procedure in GIS providing maps which suggest the more appropriate and feasible intervention type to mitigate landslide risk. These maps are not intended for replacing the designer engineering judgment, nor his work, but to help him in the choice and to help the territorial protection agencies in planning interventions and allocating funds. In order to make available these results to technical staff of public administrations, designers and insurance companies, operating in landslide risk management, the maps referred to Genoa have been published, as an example, on a webGIS site. In the paper, the proposed methodology is described and validation cases are reported. [ABSTRACT FROM AUTHOR]

Nepal is known as the most landslide-prone country due to its fragile and diversified geographical structure, climatic change, active tectonic zones, and unplanned settlements in the mid-hills. This research employed a hybrid methodology, combining quantitative and qualitative approaches, to gain insights into the lived experiences of landslide victims in Bahrabise Municipality, which is the most landslide-prone area of the country. The study involves household questionnaire surveys, interviews, and focus group discussions (FGD) with 205 participants in three major landslide areas: Jambu, Ghumthang, and Jure. The study highlighted how landslides have affected on the livelihood's security in rural Nepal. Based on the results, landslides not only caused deaths and injuries but also inflicted livelihood insecurity in the landslide-prone area. The survey findings indicate that livelihood indices such as food, shelter, and employment are most deficient, while education and health have not been significantly affected. However informal interviews and FGD provide insights into displacement, psychological distress, and health challenges for victims. This paper contributes to the knowledge base as it focuses on a specific geographical area and provides localized insights into the effects of landslides on livelihood security. Policymakers and local communities can use the findings of this study as a basis for intervening in how to improve degraded livelihood security in the future. • Provides insights into multifaceted consequences of landslide on livelihood-security. • A mixed method was used with 205 participants in landslide prone area of Nepal. • Enhancing livelihood security in research areas necessitates income diversification. [ABSTRACT FROM AUTHOR]

Effective detection of groundwater in landslide areas is crucial for landslide monitoring. The magnetic resonance sounding (MRS) method is a geophysical technique that can directly detect groundwater. However, its application in landslide groundwater monitoring is often hindered by the complex topography of landslides. This paper presents an MRS framework that accounts for the impact of landslide topography on groundwater detection. The framework includes the use of drone photogrammetry to obtain high-precision topography data and real-time kinematic equipment to acquire the coordinates of key points along the MRS coil. A three-dimensional finite element model is then constructed to calculate the alternating magnetic field generated by the MRS coil and the kernel function required for MRS inversion. Two typical landslide topography models—terrace and gully—are constructed and analyzed using numerical simulations. The results indicate that landslide topography significantly impacts the quality of groundwater information retrieved by MRS in both one-dimensional and two-dimensional inversions, affecting the accurate detection and identification of infiltration surfaces, sliding zone water, and bedrock surfaces. If accurate topography data are obtained and appropriate kernel functions are calculated, the accuracy of the inversion can be greatly improved. An example of using the MRS method to detect groundwater in a complex landslide in the Three Gorges Reservoir area of China is then presented. The MRS inversion results that consider landslide topography are confirmed using borehole data, electrical resistivity tomography detection results, and on-site drainage tunnel investigations. The water-content distribution inside the landslide body is obtained, providing information helpful to define sliding zones in multi-level landslides. The proposed landslide MRS detection framework makes it possible to apply MRS methods to the detection of landslide groundwater distribution, analysis of seepage fields, and discrimination of landslide geological structures. • Landslide topography significantly affects the quality of groundwater information retrieved by MRS. • Obtaining accurate topography data and calculating appropriate kernel functions improve MRS inversion results. • MRS field work on a complex landslide is validated by borehole data, ERT, and on-site drainage tunnel investigations. [ABSTRACT FROM AUTHOR]

In this paper, we propose a generalized regression neural networks (GRNNS) with K -fold cross-validation (GRNNSK) method for predicting the displacement of landslide. Furthermore, correlation analysis is used to find the potential input variables for this predicting model, such as Pearson cross-correlation coefficients (PCC) and mutual information (MI) are applied in this paper. Tests on two case studies of Liangshuijing (LSJ) and Baishuihe (BSH) landslide in the Three Gorges reservoir area of China demonstrate the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

Coarse particles move towards the front and surface of the deposit, while fine particles stay in the rear and bottom. Accordingly the coefficient of permeability of the soil statistically tends to decrease from the surface to the bottom and from the toe to the apex of the deposit. This feature can be described by trend functions that describe the changes in particle size and permeability inside the soil deposit. In this paper, attempts are made to include the physical background in the characterization of geotechnical uncertainties. The objectives of this paper are to simulate non-stationary fields of particle size and coefficient of permeability in a landslide soil deposit, and to analyse rainfall infiltration in the non-stationary random fields. The soil deposit is assumed to consist of inter-layers parallel to the slope surface. The soil deposit is also assumed to be axisymmetric; therefore, any vertical section of the deposit can be selected to generate two dimensional non-stationary random fields. Each of the non-stationary random fields is formulated by adding a trend surface to a residual stationary random field with orthogonal major and minor scales of fluctuation. The produced random fields follow an exponential correlation structure. Subsequently, steady-state rainfall infiltration in the anisotropic non-stationary heterogeneous random fields is analysed. The effects of variations of saturated permeability and scale of fluctuation on the pore-water pressure regime are also investigated. [ABSTRACT FROM AUTHOR]

Recent physical model studies of landslide behaviour in loose, granular slopes have illustrated that the soil at the base of a slope may be of heightened risk of liquefaction as this area is located directly in the path of monotonic shearing events (i.e. localised toe failures) and is often saturated by groundwater. The objective of this paper is to further investigate the factors that influence the possible transition of a small toe slide to a larger and higher mobility liquefaction flow failure. Specifically, this paper investigated the influence of stress-level and soil-layer thickness between two different laboratory testing methods in controlling whether a slide transitions to a flow in physical model flume tests. Observations from two flume experiments were contrasted: one in which suction stresses were designed to dominate (a 0.33 m soil layer in a large-scale 1 g test) and a second enhanced gravity test performed in a geotechnical centrifuge where the body stresses are more representative of field scale landslides (i.e. behaviour representative of a 1.5 m thick soil layer). While the centrifuge test was brought to widespread liquefaction failure under increasing seepage flow, the 1 g flume test experienced liquefaction, but only displaced 25 mm. The results from this study highlight the dominant effect matric suction can have on the mobility of landslides, and provides a clear demonstration of the danger of misinterpreting the behaviour observed in small scale 1 g models as being fully accurate representations of larger field-scale landslide behaviour. [ABSTRACT FROM AUTHOR]

Drawing on research on landslide risk reduction in Nepal and the impacts of the Indian Ocean tsunami of 2004 in southern Thailand, this paper considers how risk, in the context of natural hazards, is produced by processes of social and economic transformation; understood and experienced by vulnerable groups; and framed by governments and experts. In so doing, we propose an agenda for more effective disaster risk management. We open the discussion by exploring the spatiality of risk, vulnerability and opportunity in the two research contexts, in particular, why people live in hazardous places and the processes that explain the intersection of human settlement and livelihoods on the one hand, and risk on the other. The paper then turns to consider the way that "risk"-and the framing and prioritisation of risk(s) by governments, experts and by vulnerable groups themselves-plays a role in setting the disaster risk management agenda. Underpinning this is the hidden question of what evidence is used-and valued-in the identification and delineation of risk. In order to understand disaster vulnerability, we argue that it is necessary to look beyond the immediate "hazardscape" to understand the wider risk context both spatially and structurally. Effective disaster risk management requires not only an appreciation of the different framings and understandings of risk, but a true integration of knowledge and expertise. [ABSTRACT FROM AUTHOR]

Tunnel excavation in mountainous or sloping regions can sometimes reactivate or accelerate landslide phenomena with a potential important impact on the stability of such constructions. The problem of tunnelling-induced landslides, that represents an important issue for many areas of the world, is very complex to analyse and demanding to solve. In addition, there are very few well documented case histories in literature. The paper presents the case of the Val di Sambro twin tunnels excavated in a structurally complex formation, in a geomorphological setting characterised by landslides of various areal sizes, whose depth was not well known before tunnelling. After a description of the main technical features of the tunnels, the geological setting and the geomechanical site conditions, the paper illustrates and comments the most significant outcomes of the monitoring system in the Southern zone of the tunnels, one of the areas where the major deformative phenomena occurred. The Val di Sambro tunnels represent a unique case study for the large amount of monitoring data collected before and during the tunnel excavation through an integrated system, consisting of various measure methods (inclinometers, piezometers, underground and surface topographic measurements, SAR interferometric technique). The combined use of surface, subsurface, underground and satellite data allowed analysing the characteristics of the landslide movements before the tunnel excavation and in relation to the tunnel construction. [ABSTRACT FROM AUTHOR]

This paper studies the run-out of earthquake-induced landslides. There are more than 20 mechanical models to explain long run-out of rapid landslides including some earthquake-induced landslides. However, notably few of them considered the effect of seismic loading on the run-out of landslides. In a previous study, we have proposed a model, which is called the multiplex acceleration model (MAM), to interpret the long run-out mechanism, and a shaking-table test has been performed to verify the MAM. Because the previous MAM is a conceptual model and only a single stone has been examined under sine waves by the shaking-table test, the MAM needs to be extended and further verified. In this paper, the MAM was extended by introducing the movement change that was induced by the so-called trampoline effect of earthquake loading, and the latest practical numerical simulation program, discontinuous deformation analysis (DDA), was used to verify the mobility of earthquake-induced landslides. After a conceptual landslide model was used to verify the effect of seismic loading on the mobility, the Donghekou landslide, which was a typical long run-out landslide that was induced by the 2008 Wenchuan earthquake, was analyzed. The results show that: the seismic loading could be one of the factors that could eventually help increase the run-out of landslides. [ABSTRACT FROM AUTHOR]

The 2018 Hokkaido Eastern Iburi Earthquake caused a large number of slope failures/landslides over a wide area. In particular, the enormous damage due to slope failures was centered in the towns of Atsuma and Abira which are located to the north of the epicenter. In Atsuma, a seismic intensity (Japan Meteorological Agency) of seven was observed. This was the first time an earthquake of such a large seismic intensity was recorded in Hokkaido, Japan. The geology in this region was mainly formed by three kinds of pyroclastic fall deposits (fa) due to the erupting of Mt. Tarumae, Mt. Eniwa and Shikotsu Caldera. The most serious damage was generated in these tephra stratus. In addition, the large-scale sliding of rock slopes composed of mudstone occurred in the Hidaka-Horonai River Basin in the Horonai district of Atsuma, and its debris flowed into the river and caused the blockage of the river channel. This paper summarizes the earthquake-induced damage to natural slopes, and presents the physical features and the mechanical properties of the collapsed pyroclastic fall deposits distributed over this area. [ABSTRACT FROM AUTHOR]

The complicated seismic response of earth slopes and the transition mechanism from progressive to catastrophic motion of landslides have long been recognized as one of the most challenging research topics in geotechnical earthquake engineering. In this paper, this fundamental conundrum will be tentatively unveiled from a new perspective combining the seismic slope displacement analysis with (mechanical) dynamic porewater pressure feedback of the shear band soils against the earthquake excitation. We present both the conceptual scheme and the calculation framework to numerically study the dynamic changes of porewater pressure, shear strength parameters, and hydraulic properties of the shear band soils. Their significant influences to the change of earthquake-induced landslide movement modes are systematically investigated. Different dilation angles are chosen to characterize the shear dilation and shear contraction processes in the shear band soil, while the dynamic porewater pressure feedback in the shear band soil during the continuous seismic displacement is investigated. The results show that the seismic slope displacement and failure strongly depend on the mechanical feedback of the shear band soil. When the dilation angle is positive, the porewater pressure feedback in the shear band during the slope movement is negative, and the effective resistance stress increases, which is not susceptible to catastrophic motion. On the other hand, when the dilation angle is negative, the positive porewater pressure feedback may lead to catastrophic failure. At last, the effects of shear softening/hardening combined with dilation angle evolution on the ultimate slope movement mode are also put forward. [ABSTRACT FROM AUTHOR]

Water impoundment combined with more frequent precipitation extremes due to climate change increases landslide hazards on the slopes surrounding dam reservoirs. In situ monitoring systems in these potential landslide-prone areas are often unavailable, making landslide failures challenging to forecast. This paper describes a multisensor and multivariate remote sensing approach using data from Envisat, Sentinel-1, Landsat and PlanetScope satellites to reconstruct the spatiotemporal evolution of the mechanism and causes of the March 2019 landslide failure backside of the dam reservoir in Hoseynabad-e Kalpush village, north–central Iran. Statistical analysis and time series clustering are performed to derive the main landslide kinematic features from multitemporal interferometric synthetic aperture radar (MT-InSAR) analysis. We also exploit GIS and wavelet analysis to correlate potential external driving factors with landslide kinematics. Envisat and Sentinel-1 MT-InSAR analyses revealed that a previously stable old landslide was reactivated following reservoir impoundment in early 2013. As the reservoir water level rose during the following years up to 34 m in 2019, the landslide displacement rate gradually increased from 3.5 cm/yr to 8.4 cm/yr, and the destabilization gradually propagated upslope. At this stage, seasonal precipitation effects were detected only in the vertical component, indicating swelling and shrinkage movements of the shallower soil layer. The reactivated landslide accelerated and catastrophically failed following the exceptional precipitation in early 2019, producing a horizontal shift of >40 m, detected with optical image digital correlation. In the aftermath, the landslide continued to move with a decreasing trend until final stabilization in October 2021. Our study demonstrates how combined observations derived from multisensor satellite remote sensing data can be used to assess landslide precursors and kinematics, as well as the influence of climatic and anthropogenic factors on the instability of slopes surrounding water reservoirs. This is especially relevant in data-scarce areas. • Deep-seated landslide pre-, co- and post-failure analysis using satellite remote sensing. • Anthropogenic, environmental and climatic interaction in slope instability in Iran. • MT-InSAR shows landslide reactivation following impoundment in a nearby reservoir. • Slow-moving landslide failure following extreme precipitations detected using DIC. • Post-failure motion with negative quadratic decay trend linked to reservoir drawdown. [ABSTRACT FROM AUTHOR]

• Revealed the damage type and disaster mechanism of the landslide creep to the bridge. • Analyzed correlation between the deformation of bridge and landslide. • Analyzed the improper reasons for each treatment scheme of Zhengiawan ancient landslide. • proposed a complete set of solutions for bridge site slope control and treatment. The bridge site slope in Zhengjiawan has been renovated several times in response to the adverse geological conditions of the Zhengjiawan ancient landslide (ZAL) in China. However, improper control and treatment measures have caused the structural failure of the Zhengjiawan bridge (ZB). Based on long-term field monitoring data of rainfall, temperature, bridge deformation, and bridge site slope displacements, this paper analyses the impact of repeated improper treatment on bridge site slopes to bridge across. Furthermore, it summarized the interrelationship between bridge deformation and bridge site slopes under natural rainfall and improper treatment measure conditions, and proposed a set of solutions for bridge site slope control and treatment. The results show that the destruction of ZB is primarily attributed to the deformation of ZAL, natural rainfall is the main trigger controlling the intermittent creep of the ZAL, while the construction of anti-slide pile and deviation rectification of bridge abutment result in significant deformation of ZAL. The deformation of ZB and ZAL were synchronous, and the monthly displacement difference ranged from 0.18 to 5.19 mm. The failure of the ZB structure resulting from the ZAL is attributed to the insufficient shear strength of the weak loose soil comprising the landslide, which fails to withstand the sliding force induced by continuous heavy rainfall. Additionally, the original anti-slide pile inadequately controls the deformation of the landslide. By setting the second-row anti-slide pile, adding the cross-sectional area of the bridge pier foundation, and installing drainage pipes, the safety of the bridge is effectively guaranteed. The control and treatment of ZAL show that preventing bridge pier deformation should be prioritized followed by controlling and treating bridge site slopes, and this study provides insights into interactions between unstable landslide treatments and bridge structures which may serve as a reference for similar projects. [ABSTRACT FROM AUTHOR]

This paper aims to study the ductile fracture mechanism of API X65 buried pipes including crack initiation and propagation using the extended finite element method (XFEM). First, the crack evolution histories of X65 specimens with initial crack-like flaws during tensile and three-point bending tests are illustrated, and the numerical results are compared with experimental data. In addition, effects of different crack configurations, damage initiation and evolution criteria are investigated. Second, the burst processes of straight pipes with initial gouge flaws are presented, and the FE results are compared with assessment in related standards and experiments. Finally, the crack onset and growth of buried pipes due to deflection arising from landslide movements are predicted, and the numerical results are compared with previous study. Particularly, the internal pressure, wall thickness, and soil properties on crack behavior and limit load-bearing ability are investigated. This paper provides a fundamental support for the integrity assessment and safety evaluation of buried pipes. [ABSTRACT FROM AUTHOR]

• The paper deals with experimentation and modelling of pore fluid composition influence on swelling and swelling pressure of a low activity clay. • Swelling and swelling pressure were induced by unloading or by exposure to distilled water of a soil reconstituted with NaCl solutions. • The observed processes were modelled with the FEM method by using a user-defined UEL subroutine implemented in the commercial code ABAQUS. • An extended elasticity law constitutive model is proposed and coupled chemo-mechanical interactions are considered. • A simplified slope stability analysis shows that the role of swelling/swelling pressure onset on the stability of a slope in low activity clay. The behaviour of soils and rocks containing clay minerals is the effect of complex chemo-mechanical processes of interparticle interaction. This paper presents experimental results and model simulations of the influence of mineral composition and pore fluid composition on swelling and swelling pressure of clayey soils frequently affected by instability problems. The soil from a landslide in tectonized clay shales, characterized by wide ranges of plasticity and activity, was analysed. Soil fractions at different liquid limit w L were reconstituted with distilled water or salt solutions at different concentrations and they were compressed in oedometric conditions. The tendency to swell was induced by unloading or by exposure to a fluid different from the pore fluid. Swelling was permitted in a set of specimens and it was prevented in another set by applying increasing pressures. The temporal evolution of swelling and swelling pressure was monitored, and ion concentration in the pore fluid was evaluated by monitoring the cell fluid composition. The chemically induced swelling was very large in the most plastic soil and negligible in the least plastic. Swelling pressure too attained different values, however, it was also very large in the least plastic soil. The observed coupled chemo-mechanical processes were successfully modelled with the FEM method by using a user-defined UEL subroutine that was implemented in the commercial code ABAQUS. The subroutine takes account of the chemo-mechanical interactions in the solid skeleton, through a suitable constitutive model, and of the coupled fluxes in the porous space, in addition to water desorption/adsorption at clay platelets. In the proposed constitutive model, chemical interactions are assumed to affect both the plastic and the elastic response, as it was observed in experiments, thus an extended elasticity law is proposed. A simplified analysis, calibrated on the model results, shows that the role of swelling/swelling pressure on slope stability is significant even in the case of the least active soil. A decrease in pore solution concentration thus provokes two effects that are both negative for slope stability: a decrease of strength parameters and an increase of horizontal stresses. [ABSTRACT FROM AUTHOR]

This paper presents a case study of landslide during tunneling period in hilly topography, and a practical treating countermeasure is also proposed in the study. The field investigation and numerical analysis demonstrate that tunneling in hilly topography with sloping stratification has risk of landslide while heavy rainfall permeates into ground, and a treating countermeasure of anti-slide piles combined with in-layer compacted backfilling is adopted in the practical implementation. Moreover, the implemented treating work demonstrates that the employed countermeasure is capable of treating landslide during tunneling with heavy rain water permeating into ground, which can provide the design basis for similar treating work. • A case of landslide during tunneling is presented. • The landslide is caused by tunneling in hilly topography with heavy rainfall. • The primary cause of landslide during tunneling can be numerically clarified. [ABSTRACT FROM AUTHOR]

Abstract Differential Interferometric Synthetic Aperture Radar (DInSAR) techniques have repeatedly proved to be an effective tool for built environments monitoring in areas affected by geological hazards. This paper describes how the Coherent Pixel Technique (CPT) approach has been successfully applied to assess the response of an unstable slope to the different phases of remedial works following a landslide event. The CPT technique was performed on 59 COSMO-SkyMed images obtained between May 2011 and August 2016 and centred on the Quercianella settlement (a small hamlet of Livorno municipality, Tuscany, Italy), where the reactivation of a dormant shallow slide had occurred in March 2011 and, hereafter, a geotechnical intervention, designed with the aim of mitigating the risks, has been conducted from August 2013, lasting thirteen months. The time series of CPT results show a deformation pattern with sudden accelerations (up to 21 mm in few months) corresponding to the beginning of the interventions, during which the area has been excavated to install a drainage well, followed by mild decelerations resulting from the stabilization of the area after the conclusion of the works. In particular, the integration of ground-based subsurface monitoring (inclinometers and piezometers) and DInSAR superficial data has provided consistent results for landslide characterization and helped defining the state of activity and the areal distribution of the sliding surface. Moreover, the performance of remedial works in the landslide-affected area has been observed, showing stabilization in the upper part of the hamlet and the ongoing movement in the lower part. The combined monitoring system also led the geotechnical company in charge of remedial works to design further stabilization works in order to preserve buildings and roads in the moving area. Therefore, the integration of remote sensing techniques and in situ instruments represents a timely and cost-efficient solution for intervention works monitoring, opening new perspectives on designing engineering solutions for the stabilization of unstable slopes. Highlights • DInSAR and conventional monitoring techniques were applied in Livorno, Italy. • Such integration supported the design of remedial works of the landslide. • The performances of the drainage well were observed by DInSAR and inclinometers. • The monitoring system led the company in charge to plan further stabilization works. [ABSTRACT FROM AUTHOR]

The interaction between Newtonian and non-Newtonian fluid is one the most complicated problems for the engineers in the field of fluid mechanics. In the last decades, Lagrangian methods including smooth particle hydrodynamics has had the great interests among the different approaches in computational fluid dynamics (CFD). In this paper the collapse of the granular column and dry landslide and also two phase dam break and submerged landslide phenomena have been done through open source SPHysics2D code. The proposed model describes both fluid and sediment particles as weakly compressible flow where the sediment is treated as a non-Newtonian fluid using a viscoplastic model, called μ(I) model. This model is based on the properties of grains including inertia and friction coefficient. First, the performance of the viscoplastic code was investigated for a one- phase model by comparing the results measured in the laboratory and those obtained by developed code. Then, the movable dam break and submerged landslide phenomena were investigated, by the code developed for a two phase model, including Newtonian and non-Newtonian fluid. μ(I) viscoplastic model is utilized for the solid phase, Owen's equation and the mean harmonic viscosity are used to introduce the interactions between the particles containing different viscosities and densities. Results show that the model used in this research has reasonable accuracy by comparing with experimental models. Unlabelled Image • SPH and μ(I) model are used to simulate the interaction of two phase fluid flow. • The interactions between phases of different kinds are shown using Owen's equation. • The collapse of a granular column and dry landslide phenomena are shown. • Two-phase dam break and subaerial/submerged landslide are also investigated. [ABSTRACT FROM AUTHOR]

The Axmouth to Lyme Regis Undercliff National Nature Reserve contains three highly unusual landslides; the Plateau, Dowlands and Bindon. The failure surface of the Plateau landslide is clearly within the Triassic strata rather than on the Jurassic-Cretaceous unconformity, which is the primary failure surface elsewhere along this coast. The nature of the famous Bindon Landslide of 1839, which formed Goat Island and the Chasm, has been the subject of much debate since it was first described by Buckland and Conybeare in 1840. While it is broadly agreed to be a translational failure, the stratigraphic location of the failure surface is still not agreed. This paper examines the Plateau slip in detail and attempts to apply what can be seen there to Dowlands and Bindon. While Pitts undertook a highly detailed mapping exercise of the landslides throughout the undercliff itself, he did not map the foreshore in any detail. Therefore an Unmanned Aerial Vehicle or drone was used to generate a high resolution photomontage of the foreshore in front of all three landslides to enable detailed mapping of the features contained within it. The results are available on the web. The mapping does not resolve the question of the location of the failure surface of both Dowlands and Bindon but it provides further detail for interpretation. [ABSTRACT FROM AUTHOR]

Abstract Frozen debris lobes (FDLs) are slow-moving landslides along permafrost-affected slopes, and consist of soil, rock, organic debris, and areas of massive infiltration ice. Based on their proximity to the adjacent infrastructure, their size, and their flow dynamics, FDLs represent potential geohazards. Eight FDLs (FDL-A, -B, -C, -D, -4, -5, -7, -11) within the Dalton Highway corridor in the Brooks Range, Alaska, USA are the subject of this paper. We examined temporal and spatial variation of FDL displacement using medium-resolution Synthetic Aperture Radar (SAR) images and differential SAR Interferometry (dInSAR) techniques. European Remote Sensing satellite 1/2 (ERS 1/2) and Phased Array type L-band Synthetic Aperture Radar (PALSAR) acquisitions were used to generate coherent interferograms to study the displacement history of FDLs for 1995–1996 and 2006–2010. We conducted an initial assessment of the capability of satellite InSAR to monitor FDL movement depending on data resolution, season, and vegetation coverage, which also helped us to select useful interferograms. With multi-temporal interferometric displacement maps, we found that seven investigated FDLs (FDL-7 was excluded from this sub-experiment due to limited data coverage) demonstrated strong spatial and seasonal variations in their movement patterns, with maximum displacement rates typically occurring in October and minimum displacement rates during February or March, which is consistent with previously published field study results. Overall, through this study we: (1) delineated the active FDLs during the winter period using a wrapped PALSAR interferogram; (2) analyzed the spatial variation of the deformation field within each FDL body; (3) modeled the seasonal changes of FDL deformation rates through the analysis of multi-temporal ERS tandem interferograms; and (4) integrated InSAR-derived deformation rates with those obtained through historical imagery analysis to determine long-term deformation rates. Results from this study fill the gaps left in the historical imagery analysis and provide important seasonal and spatial deformation data, which are essential in the development of a mitigation plan as these features approach infrastructure. We also summarize our research experience studying these moving features using satellite radar interferometry and believe this can be useful for future studies of similar features. Highlights • Inventory map of frozen debris lobes (FDLs) along the Dalton Highway in northern Alaska • Seasonal movement rate change retrieval from ERS Tandem pairs • FDL movement history analysis with multi-source datasets [ABSTRACT FROM AUTHOR]

Abstract Most dynamic response analyses of rock slopes only consider the vertical incidence of seismic waves. However, obliquely incident waves dominate in near-field seismic areas. This paper presents a new seismic input method that considers near-field oblique incidence based on mechanisms of artificial viscous boundaries and the influence of incident angle on the dynamic response of rock slopes. Three numerical model slopes with different slope angles of 30°, 45° and 60° are excited with the El Centro earthquake record assuming varying incident angles from 0° to 90°. The results show that the incident angle significantly affects the dynamic response of the slopes. The most damaging incident directions are approximately perpendicular to the slope surface, rather than in the vertical direction. The dynamic response of the slopes will be underestimated if only the vertical incidence is considered. The incident angle affects the reflection wave field in the slope and the areas affected by the reflection waves decrease with increasing slope angle. However, the predominant period of the response spectrum of the rock slopes is not sensitive to the incident angle and location. This study unveils the dynamic mechanism of earthquake-induced rock slides, which is of significance for earthquake hazard prevention. Highlights • Oblique incident waves prevail in near-field seismic areas. • An input method for seismic response analysis including oblique incidence is developed. • The dynamic response of rock slopes will be underestimated if only the vertical incidence is considered. • Back slopes tend to respond more violently than face slopes do. • The most damaging incident direction is approximately perpendicular to the slope surface. [ABSTRACT FROM AUTHOR]

The evaluation of forces due to the impact of flow-slides against structures is essential for both risk assessment and protection structure design. However, the impact process is very complex and not fully understood yet. Peak forces are in fact commonly evaluated by simplified empirical methods whose reliability is questionable. In this paper, the impact process is numerically investigated by comparing the results obtained from software based on a discontinuous Discrete Element Method (DEM) and a continuous Material Point Method (MPM). The impact process and its key features are highlighted and the principal parameters influencing the peak force value are identified. This study focuses on the impact phase, rather than on the propagation phase. The soil mass is initially positioned in front of the wall with a prescribed uniform velocity and the evolution of the impact force is monitored. [ABSTRACT FROM AUTHOR]

This paper studies the influence of burial depth on slope response and pipe performance under earthquake induced landslide. Three physical models are constructed and tested using 1 g shaking table device. The slope is divided into four sections as toe, lower and upper sections of the slope face and crest. The pips which perpendicularly cross the slope are embedded at these positions in three burial depths to demonstrate burial depth effect in each section. According to the experiments, dynamic slope response which moderately develops at deeper depths at toe and lower section, displays a clear downtrend at upper section and crest. Also, the pipe response depends on pipe route and slope displacement pattern. The pipe deformations have positive correlation with depth at upper section and crest, but show opposite behavior at toe and lower section. Moreover, the horizontal strains impact on total strains in buried pipes reduces at greater depths. [ABSTRACT FROM AUTHOR]

Landslides in sensitive clays pose a major threat to life, property and the environment. The lack of warning signs and the extreme mobility of quick clays increase the risk. When occurring along fjords, lakes or large rivers, the landslides can generate destructive tsunamis. Historical records show that 45% of the shoreline landslides in marine sediments in Norway triggered tsunamis with run-up height of 1 to 15 m. To improve the management of the hazard and risk due to landslides in sensitive materials, the profession needs to develop tools for modelling the mobility of landslides and their tsunamigenic potential. The paper back-calculates the 1978 Rissa landslide, one of the largest quick clay landslides in Norway. Because of the quantity of data available, the Rissa landslide provides a unique benchmark to study the mobility of the quick clay, and the tsunami following the landslide. The paper describes a new approach to model landslide mobility and tsunami run-up, and presents the results of the analyses and a comparison of the results with the observations. The back-calculated mobility (runout distance, flow velocity and debris thickness) and wave run-up on the lakeshore agreed well with the measurements. [ABSTRACT FROM AUTHOR]

Numerous factors are necessary to comprehensively comprehend the complex phenomenon of landslides and, ultimately, facilitate effective measures for their protection and management. This paper investigates the case history of the Maicher landslide in the Nagar District (Northern Pakistan) by using a multidisciplinary combined technique approach based on conventional geophysical measurements and modern remote sensing techniques. The first technique is to identify the rate of deformations with real-time landslide monitoring sensors and satellite images. Care is devoted to data acquisition and processing using the ad-hoc methodology to minimize errors and ensure high reliability. For the second technique (electrical resistivity tomography, surface waves measurements, and ground-penetrating radar), convenient methods for landslide characterization are used and herein presented. The combination of information taken from the different techniques allows the results to be validated by conventional and modern approaches and enhances the accuracy of each method. The results suggest that shear surface planes at a depth of 35–40 m have developed over time. The analysis also provided information on controlling factors and possible expansion of the different slope sections. This work highlighted that geophysical parameters (shear wave velocity Vs, dielectric constant ε, and resistivity value ρ) could provide reliable qualitative and quantitative information about the shallow layer, bedrock contacts, possible sliding surface and subsurface water saturation, and seepage system of a landslide. The geophysical results reflect an overview of the geological model and are effective in terms of the slope stabilization process. • 3D landslide modelling for hazard assessment using geophysical methods. • Landslide residual risk assessment using geophysical techniques. • Time-series deformation assessment of natural slope. • 3D slope model development from geophysical investigations. [ABSTRACT FROM AUTHOR]

• Comparison of the point cloud at the initial moment and the landslide moment saves the time of manual selection of image segmentation thresholds. • The change of landslide depth information at different moments as a condition for landslide area determination makes the method more generalizable. • The initial point cloud plane fitting equation and K-means clustering segmentation are used for denoising to make the landslide area boundary determination more accurate. • The comparison with the traditional two-dimensional identification method verifies the high accuracy, rapidity and wide applicability of the new method. Accurately recognizing landslide deformation regions is important for understanding the mechanisms of landslides and predicting landslide disasters. Using slopes in Dayu County, China, as the research background, this paper simulates slopes using a similar test model test and proposes a new method of automatic identification based on depth information. By comparing the depth information of the initial point cloud with that of the landslide point cloud, the landslide deformation area is preliminarily extracted. The preliminarily extracted landslide deformation area is oversegmented by the k-means clustering algorithm. The slope equation fitted with the initial point cloud data is used to distinguish each segmentation block, and the error caused by the initial segmentation is removed to obtain the final recognition result. For validation, 12 images of landslides were quickly identified. The identification time was approximately 281 s. The average relative error of the method in the X and Y directions is 2.34 % and 0.71 %, respectively. The traditional two-dimensional recognition method, on the other hand, has a recognition time of approximately 720 s; the average relative errors in the X and Y directions are 6.61 % and 3.90 %, respectively. The advantages of our method are listed as follows: 1) It improves the segmentation quality of the landslide deformation area, especially in the deformation boundary. 2) Landslide areas with similar colors but large depth variation can be more accurately identified by using depth information. 3) It has the characteristics of real-time monitoring and fast operation. In addition, the new method is used to identify the area and volume of the landslide in the three states, and the results are in accordance with the theory. [ABSTRACT FROM AUTHOR]

Outgoing migration flows can influence demand, availability, location and quality of housing in the areas from which they originate, through dynamics such as remittance transfer and investment, cultural change, demographic decline and loss of skilled work. These dynamics may have diverse implications on disaster risk, potentially affecting the occurrence or intensity of some hazardous events and determining the levels of exposure and vulnerability of people and assets. This paper retraces the evolution of the housing stock as a product of outmigration in San Mango sul Calore and Cavallerizzo di Cerzeto, two mountain villages in Italy's Southern Apennines, in the decades preceding recent disasters. Over the second half of the 20th century, both municipalities witnessed intense outmigration, contributing to the expansion of their respective settlements' housing stock and the abandonment of traditional land-use patterns and building practices. These processes shaped hazard exposure and disaster vulnerability of different people in each community, producing a diversity of risk reduction and risk creation outcomes. This paper analyses the context-specific migration trajectories and risk outcomes in the two study areas, framing them through the findings of the global literature on migration, development and DRR, to identify theoretical implications and operational approaches relevant to understanding and addressing migration-housing-risk dynamics. Its insights can support risk reduction in places experiencing intense population outflows and related demographic and physical transformations. [ABSTRACT FROM AUTHOR]

The development of unmanned aerial vehicle photogrammetry over the last decade has allowed terrain that is very difficult for humans to access to be captured at very high spatial and temporal resolutions. This paper deals with the application of this technique to the study of extreme topography in a near-vertical road cut-slope. Three photogrammetric projects were carried out: one derived from images taken with the camera oriented horizontally, one derived from images taken with the camera tilted at 45°, and one derived from both sets of images. Point clouds and orthophotos were generated for each of these projects. The best accuracies were achieved by the photogrammetric products derived from the combined images set, which had RMSE equal to 0.053 m, 0.070 m and 0.061 m in X, Y and Z direction, respectively. A software program was developed to generate contour lines and cross-sections derived from the point cloud, which was able to represent all terrain geometric characteristics, such as several Z coordinates for a given planimetric (X, Y) point. Furthermore, comparing the contour lines and cross-sections generated from the point cloud using the program developed in this project to those generated from the digital surface model showed that the former are capable of representing geometric terrain characteristics that the latter cannot. [ABSTRACT FROM AUTHOR]

In this paper, a hybrid machine learning ensemble approach namely the Rotation Forest based Radial Basis Function (RFRBF) neural network is proposed for spatial prediction of landslides in part of the Himalayan area (India). The proposed approach is an integration of the Radial Basis Function (RBF) neural network classifier and Rotation Forest ensemble, which are state-of-the art machine learning algorithms for classification problems. For this purpose, a spatial database of the study area was established that consists of 930 landslide locations and fifteen influencing parameters (slope angle, road density, curvature, land use, distance to road, plan curvature, lineament density, distance to lineaments, rainfall, distance to river, profile curvature, elevation, slope aspect, river density, and soil type). Using the database, training and validation datasets were generated for constructing and validating the model. Performance of the model was assessed using the Receiver Operating Characteristic (ROC) curve, area under the ROC curve (AUC), statistical analysis methods, and the Chi square test. In addition, Logistic Regression (LR), Multi-layer Perceptron Neural Networks (MLP Neural Nets), Naïve Bayes (NB), and the hybrid model of Rotation Forest and Decision Trees (RFDT) were selected for comparison. The results show that the proposed RFRBF model has the highest prediction capability in comparison to the other models (LR, MLP Neural Nets, NB, and RFDT); therefore, the proposed RFRBF model is promising and should be used as an alternative technique for landslide susceptibility modeling. [ABSTRACT FROM AUTHOR]

This paper proposes an approach for landslide inventory mapping considering actual conditions in Indonesia. No satisfactory landslide database exists. What exists is inadequate, focusing, on data response, rather than on pre-disaster preparedness and planning. The humid tropical climate also leads a rapid vegetation growth so past landslides signatures are covered by vegetation or dismantled by erosion process. Generating landslide inventory using standard techniques still seems difficult. A catalog of disasters from local government (village level) was used as a basis of participatory landslide inventory mapping. Eyewitnesses or landslide disaster victims were asked to participate in the reconstruction of past landslides. Field investigation focusing on active participation from communities with the use of an innovative technology was used to verify the landslide events recorded in the disaster catalog. Statistical analysis was also used to obtain the necessary relationships between geometric measurements, including the height of the slope and length of run out, area and volume of displaced materials, the probability distributions of landslide area and volume, and mobilization rate. The result shows that run out distance is proportional to the height of the slope. The frequency distribution calculated by using non-cumulative distribution empirically exhibits a power law (fractal statistic) even though rollover can also be found in the dataset. This cannot be the result of the censoring effect or incompleteness of the data because the landslide inventory dataset can be classified as having complete data or nearly complete data. The so-called participatory landslide inventory mapping method is expected to solve the difficulties of landslide inventory mapping and can be applied to support pre-disaster planning and preparedness action to reduce the landslide disaster risk in Indonesia. It may also supplement the usually incomplete data in a typical landslide inventory. [ABSTRACT FROM AUTHOR]

The 2008 Wenchuan earthquake in Sichuan, China triggered numerous landslides in the stricken area. The loose landslide materials retained on mountain slopes and in gullies are prone to reactivation and may transform into debris flows in the rainy season. Nine years after the Wenchuan earthquake, debris flows are still active in Gaojiagou Ravine 16.5 km north of the epicentre. On 14 August 2010, 3 July 2011, 13 July 2013, and 6 July 2016, four large-scale debris flows were triggered by heavy storms in Gaojiagou Ravine. The four debris flows blocked the Minjiang River twice and caused severe damage to nearby villages and reconstruction sites. Several questions arise from these repeated debris flows. Did the level of triggering rainfall change in the four debris flow events? How did the initiation mechanism evolve over time? What are the differences in the runout characteristics in the four events? How did the check dams constructed in 2012 function in the subsequent debris flows? In this paper, we evaluated the loose deposit volumes in Gaojiagou Ravine before and after each of the four debris flows and the runout volumes, and analysed the triggering rainfall intensities, initiation mechanisms and runout characteristics of the four debris flows. The rainfall threshold for the debris flows in Gaojiagou Ravine increased over time, and the initiation mechanisms evolved from landslides to channel-bed failure, and subsequently to channel-bank erosion. The mobility of the debris flows decreased from 2010 to 2016 as the initiation positions moved lower and the particle size of the runout materials became coarser. [ABSTRACT FROM AUTHOR]

For automatic landslide detection, landslide morphological features should be quantitatively expressed and extracted. High-resolution Digital Elevation Models (DEMs) derived from airborne Light Detection and Ranging (LiDAR) data allow fine-scale morphological features to be extracted, but noise in DEMs influences morphological feature extraction, and the multi-scale nature of landslide features should be considered. This paper proposes a method to extract landslide morphological features characterized by homogeneous spatial patterns. Both profile and tangential curvature are utilized to quantify land surface morphology, and a local G i * statistic is calculated for each cell to identify significant patterns of clustering of similar morphometric values. The method was tested on both synthetic surfaces simulating natural terrain and airborne LiDAR data acquired over an area dominated by shallow debris slides and flows. The test results of the synthetic data indicate that the concave and convex morphologies of the simulated terrain features at different scales and distinctness could be recognized using the proposed method, even when random noise was added to the synthetic data. In the test area, cells with large local G i * values were extracted at a specified significance level from the profile and the tangential curvature image generated from the LiDAR-derived 1-m DEM. The morphologies of landslide main scarps, source areas and trails were clearly indicated, and the morphological features were represented by clusters of extracted cells. A comparison with the morphological feature extraction method based on curvature thresholds proved the proposed method's robustness to DEM noise. When verified against a landslide inventory, the morphological features of almost all recent (< 5 years) landslides and approximately 35% of historical (> 10 years) landslides were extracted. This finding indicates that the proposed method can facilitate landslide detection, although the cell clusters extracted from curvature images should be filtered using a filtering strategy based on supplementary information provided by expert knowledge or other data sources. [ABSTRACT FROM AUTHOR]

On 17 October 2015, a landslide of roughly 60 × 10 6 m 3 occurred at the terminus of Tyndall Glacier in Taan Fiord, southeastern Alaska. It caused a tsunami that inundated an area over 20 km 2 , whereas the landslide debris itself deposited within a much smaller area of approximately 2 km 2 . It is a unique event in that the landslide debris was deposited into three very different environments: on the glacier surface, on land, and in the marine waters of the fjord. Part of the debris traversed the width of the fjord and re-emerged onto land, depositing coherent hummocks with preserved source stratigraphy on an alluvial fan and adjacent moraines on the far side of the fjord. Imagery from before the landslide shows that the catastrophic slope failure was preceded by deformation and sliding for at least the two decades since the glacier retreated to its current terminus location, exposing steep and extensively faulted slopes. A small volume of the total slide mass remains within the source area and is topped by striated blocks (> 10 m across) and standing trees that were transported down the slope in intact positions during the landslide. Field work was carried out in the summer of 2016, and by the time this paper was written, almost all of the supraglacial debris was advected into the fjord and half the subaerial hummocks were buried by glacial advance; this rapid change illustrates how highly active sedimentary processes in high-altitude glacial settings can skew any landslide-frequency analyses, and emphasizes the need for timely field investigations of these natural hazards. [ABSTRACT FROM AUTHOR]

Every year, landslides pose huge threats to thousands of people in China, especially those in the Three Gorges area. It is thus necessary to establish an early warning system to help prevent property damage and save peoples’ lives. Most of the landslide displacement prediction models that have been proposed are static models. However, landslides are dynamic systems. In this paper, the total accumulative displacement of the Baijiabao landslide is divided into trend and periodic components using empirical mode decomposition. The trend component is predicted using an S-curve estimation, and the total periodic component is predicted using a long short-term memory neural network (LSTM). LSTM is a dynamic model that can remember historical information and apply it to the current output. Six triggering factors are chosen to predict the periodic term using the Pearson cross-correlation coefficient and mutual information. These factors include the cumulative precipitation during the previous month, the cumulative precipitation during a two-month period, the reservoir level during the current month, the change in the reservoir level during the previous month, the cumulative increment of the reservoir level during the current month, and the cumulative displacement during the previous month. When using one-step-ahead prediction, LSTM yields a root mean squared error (RMSE) value of 6.112 mm, while the support vector machine for regression (SVR) and the back-propagation neural network (BP) yield values of 10.686 mm and 8.237 mm, respectively. Meanwhile, the Elman network (Elman) yields an RMSE value of 6.579 mm. In addition, when using multi-step-ahead prediction, LSTM obtains an RMSE value of 8.648 mm, while SVR, BP and the Elman network obtains RSME values of 13.418 mm, 13.014 mm, and 13.370 mm. The predicted results indicate that, to some extent, the dynamic model (LSTM) achieves results that are more accurate than those of the static models (i.e., SVR and BP). LSTM even displays better performance than the Elman network, which is also a dynamic method. [ABSTRACT FROM AUTHOR]