Landslide Processes Research Articles

Plowing mechanism of rapid flow-like loess landslides: Insights from MPM modeling

Plowing refers to the phenomenon by which a landslide displaces and pushes the path material forward. Despite its importance in shaping the dynamics of many rapid flow-like loess landslides, the mechanism of plowing is not fully understood. Therefore, this paper presents an improved numerical model based on the material point method (MPM). This model takes into account the interactions between the landslide mass and the path material. The reliability of this model was validated by simulating two granular column collapse experiments involving interaction with an erodible mass. The model was then applied to analyze the plowing dynamics of the Ximiaodian loess landslide in Jingyang County, Shaanxi Province, China. A series of well-designed simulations were conducted to investigate this specific landslide event, contributing to a deeper understanding of the plowing phenomenon in loess landslides. The simulation results show that our model can satisfactorily simulate the plowing process of the Ximiaodian landslide. The plowing process of a rapid-flow loess landslide is proposed to consist of four distinct stages: 1) the collision stage, when the landslide strikes the terrace, resulting in the bending of its strata; 2) the shear failure stage, characterized by significant plastic shear deformation within the bent strata, resulting in the formation of multiple shear failure planes; 3) the steady plowing stage, during which the deformation structure in the affected terrace stabilizes and plowing continues in a steady pattern; and 4) the stopping stage, when the propagation of the disturbed terrace gradually stops. Furthermore, the disturbed terrace zone exhibits three distinct deformation structures. In the rear part, a stable zone develops where the terrace layers are compressed. However, due to the compressive forces exerted by the overlying loess, no significant shear deformation is observed. The middle part is the shear failure zone, characterized by the formation of multiple shear failure planes. The front part is the upheaval zone, where the terrace layers are slightly bent and tilted.

Study of the landslide process in conditions of seasonally frozen soils (landslide slope of the Vorkuta river valley)

Study of the landslide process in conditions of seasonally frozen soils (landslide slope of the Vorkuta river valley)

Active landslide detection using integrated remote sensing technologies for a wide region and multiple stages: A case study in southwestern China

While significant progress has been achieved in utilizing remote sensing technologies for landslide investigation in China, there remains a notable gap in consolidating information on applicable conditions, application stages, and workflows across various remote sensing methodologies. This paper proposes a comprehensive framework for active landslide detection, incorporating multiple stages and data sources, successfully implemented in a vast region of southwestern China. Furthermore, detailed discussions are provided on the effects of the geometric distortion, land cover type, and various InSAR methods on the accuracy of active landslide identification results. Additionally, the paper delves into the advantages of integrated remote sensing technology in active landslide investigation, encompassing the assessment of current landslide activity status, precise delineation of boundaries, identification of different deformation stages, and determination of damage patterns. Through comprehensive analysis of multisource data, it enhances understanding of the active landslide process, ultimately contributing to the mitigation of casualties and property damage.

Submarine Morphological Description of the Ancient Archipelagic Aprons in the Marcus–Wake Seamount Group, Northwestern Pacific Ocean

Herein, the morphological characteristics of submarine archipelagic aprons were presented for five guyots, Suda, Arnold, Lamont, Niulang, and Zhinyv, which are over 80 Ma years old and are located in the Marcus–Wake seamount group, northwestern Pacific Ocean. Nearly 28 landslide deposits were recognized using the bathymetry and backscatter intensity data collected from the studied guyots. Landslides and their deposits that surround seamounts are mostly related to the morphology of debris avalanches, scarps, gullies/channels, and bedforms. The morphology of the archipelagic aprons of the studied guyots indicates mutual landslide processes, including slump and distinct debris avalanches arising from a cohesive or cohesionless landslide material flow. The superimposition of debris flows and sedimentation dominates the recent stages of the studied guyots. The archipelagic aprons corresponding to convex-arc-shaped scarps exhibit larger domains compared to the invagination-arc-shaped scarps with similar lateral lengths. The scarp morphologies of the studied guyots are predominantly of the complex-arc shape, indicating multiple landslide events. Parallel and convergent gullies and channels are mostly found on the elongated landslide deposits, whereas divergent and radial gullies and channels are mostly distributed on the fan-shaped aprons. Ubiquitous sediment waves occurred on the bedforms of the distal archipelagic apron across the studied guyots because of sediment creep. Small-scale sediment waves were only observed in the channels on the aprons of the Suda guyot.

Deformation Patterns and Failure Mechanisms of Soft-Hard-Interbedded Anti-Inclined Layered Rock Slope in Wolong Open-Pit Coal Mine

Since the beginning of spring 2022, successive landslides have occurred in the eastern pit slope of the Wolong Coal Mine in Qipanjing Town, Otog Banner, Inner Mongolia, which has adversely affected the mine’s production safety. This study aims to reveal the deformation patterns and failure mechanisms of landslides. Firstly, this study establishes the stratigraphic structure of the eastern pit slope of the Wolong Coal Mine using extensive field geological surveys combined with unmanned aerial vehicle photography, drilling, and comprehensive physical exploration techniques. Indoor geotechnical tests and microscopic experiments reveal that rock mass typically exhibits the characteristics of expansibility and water sensitivity. Moreover, the mechanical parameters of the rock mass were determined using a combination of the window sampling method, the Geological Strength Index, and the Hoek–Brown strength criterion estimation theory. Finally, this study consolidates the previously mentioned insights and employs FLAC3D (7.0) software to assess the stress–strain characteristics of the excavated slope. The results indicate that the deformation mode of the Wolong open pit coal mine is the toppling failure of soft-hard-interbedded anti-inclined layered rock slopes. The unloading effect and rock expansion-induced softening lead to stress concentration at the slope corners and more substantial deformation, thereby accelerating upper slope deformation. The deformation and destabilization process of landslides is categorized into four stages: the initial deformation stage, the development stage of lateral shear misalignment, the development stage of horizontal tensile-shear damage, and the slip surface development to the preslip stage. This research offers valuable references and engineering insights for future scientific investigations and the prevention of similar slope-related geological hazards.

Slope stabilization through groundwater management with limited hydrogeological data: a case study from Majes, southern Peru

Water table rise near a cliff may trigger a landslide due to the associated increase pore pressure and decrease in frictional resistance. One main cause of water table rise is intense irrigation for agriculture in arid and semi-arid regions. One such case is in Majes, southern Peru, where a landslide has evolved near an intensively irrigated agricultural area. Mitigation strategies for landslides exist, such as physical strengthening of the cliff, but can be expensive. We describe a groundwater management approach to reduce the pore pressure in the vicinity of the cliff to either slow the propagation of an existing landslide or prevent the initiation of a new landslide. A 3D numerical groundwater flow model was built for the Majes area which employs the limited data existing on the local hydrogeology. Simulations were run to understand the connection between the hydraulic properties and the water table level change due to irrigation and pumping. Results show that through a series of pumping wells near the cliff edge, the pore pressure can be decreased effectively. Moreover, decreasing the water table via pumping can be accomplished in 25–35% of the time it took to elevate the water table level by irrigation. In addition, the pumping can capture water that could be reused for irrigation. Thus, based on our analysis, we conclude that wells could provide a groundwater management approach that keeps the pore pressure at low levels to mitigate landslide processes and simultaneously supplies water for irrigation existing and future irrigation-heavy agriculture in semi-arid environments.

Разработка математической модели поверхностного трансляционного оползня с дёрном на прямых склонах горных территорий при выпадении атмосферных осадков

Introduction. An analysis of existing studies shows that surface translational landslides on grassy slopes, along with other hazards, contribute to soil erosion and harm grazing lands. The formation of a landslide body is based on the stress-strain state of a sod and its subsequent destruction when liquid precipitation falls on the slope. The most accurate method for studying such a landslide process is mathematical modeling. The fundamental disadvantages of all existing mathematical models in this area is an incomplete system of equations that describe the stress-strain state of a surface layer of a slope during precipitation. Materials and methods. This study uses a mathematical modeling methodology based on theory of generalized functions. Results and discussion. The developed mathematical model is reduced to a system of partial differential equations. This system describes the stress-strain state of a sod, caused by the external stress field and the stress field of the swelling. The study of this system of equations and the resulting final expressions showed that the superposition of these stress fields leads to a weak bending of a potential landslide body. Separation of this body from the slope occurs under the influence of general stretching, leading to its destruction. As a result, it turns into a lumpy, loose landslide body that moves down the slope. Conclusion. The mechanism of a surface translational landslide with a sod on straight slopes of mountain territories during atmospheric precipitation has been revealed. According to this mechanism: 1) the external stress field forms a potential landslide body; 2) under the influence of the liquid precipitation, the stress field of the swelling is formed. The superposition of these stress fields leads to a movement of the landslide over a short distance. Suggestions for practical application and direction of future research. The research results can be used to prevent landslides with a sod on straight slopes of mountainous territories during precipitation. Further research directions should be related to an improvement of mathematical models of the stress-strain state of a sod under different slope topography.

Revisiting spatiotemporal evolution process and mechanism of a giant reservoir landslide during weather extremes

An updated comprehension of landslide kinematics is a prerequisite for developing effective risk assessment and emergency management in the context of climate variability and anthropogenic disturbances. This study employs a multidisciplinary approach, taking the Outang landslide in China's Three Gorges Reservoir area as a case study. We examined the spatiotemporal surface processes and time- and subzone-dependent hydrometeorological factors from 2007 to 2021, particularly identifying rainfall regimes and reservoir water levels that trigger landslide movements. Given the uneven distribution of GNSS surface markers, we introduced weighted monthly mean displacement (D) and weighted marker frequency (f), enhancing the accuracy of our insights into distinct active subzones of the landslide. Preliminary results revealed July, September and June as months of higher susceptibility, as well as months with low water levels. The early-stage deformation control by reservoir water levels is being increasingly overshadowed by rainfall, due to extreme weather events and localized anti-slip measures. Long-term surface processes have also highlighted the transformation of landslide failure modes towards a compound pattern, from a predominantly retrogressive to a thrust-dominated pattern, and even overall translation coupled with localized rotation. Furthermore, the comparative analysis of normalized displacement/strain demonstrates the power and potential of integrating multi-source monitoring data. By revisiting the evolution processes and potential deformation mechanisms of the Outang landslide, we are getting closer to understanding more about the dynamics of giant landslides in reservoir areas, and illuminate the pathway towards enhanced risk management and emergency response strategies.

Geomorphological assessment as basic complement of InSAR analysis for landslide processes understanding

Landslide research has benefited greatly from advances in remote sensing techniques. However, the recent increase in available data on land surface movement provided by InSAR techniques can lead to identifying only those areas that were active during data acquisition as hazardous, overlooking other potentially unsafe areas or neglecting landslide-specific geological settings in hazard assessments. Here, we present a case study that serves as a reminder for landslide researchers to carefully consider the geology and geomorphology of study areas where complex active movements are detected using InSAR technology. In an area extensively studied using InSAR and UAV-related techniques, we provide new insights by applying classical approaches. The area is the coastal stretch of La Herradura, and its importance lies in the fact that it has served as an illustrative example in the Product User Manual of the European Ground Motion Service, a platform that provides ground motion data on a European scale. Our approach is to revisit the area and carry out qualitative geological and geomorphological assessments supported by UAV surveys and GIS spatial analysis on a broader scale than previously published investigations. Our classical approach has yielded the following new observations, crucial for risk assessment and land management: active landslides identified by InSAR techniques since 2015 are bodies nested within large mass movements that affect entire slopes. A variety of processes contribute to slope dynamics, such as large slumps, marble rock spreading and block sliding, and surface rock falls and topples. The revised delineation of the landslide bodies reveals an area almost five times larger than previously mapped. These new findings in a well-known area highlight (1) the importance of updating and downscaling previous maps and (2) the ongoing importance of classical fieldwork and desk studies as basic complements to modern InSAR analyses.

Creep deformation monitoring of landslides in a reservoir area

Effective utilization of reservoirs facilitates the distribution of water resources in both time and space, providing strong support for the sustainable growth of the economy and society. However, the periodic water level fluctuations of a reservoir during its operation may lead to geological hazards such as landslides. Here, we conducted a comparative analysis of the deformation processes of reservoir and non-reservoir landslides in the Jilintai area between 2017 and 2022 using Interferometric Synthetic Aperture Radar (InSAR) technology and wavelet analysis. Results show that more unstable locations were found on shaded slopes with a soil moisture of 6–10% than on sunny ones with a soil moisture of 15–19%. Both reservoir and non-reservoir landslides showed continuous and prolonged creep displacement over time. The deformation curve of the reservoir landslides displayed a step-like trend, whereas it was a linear trend without the discernible acceleration period for the non-reservoir landslides. Furthermore, the wavelet analysis revealed that the deformation of reservoir landslides follows a one-year period, almost synchrony with reservoir level changes. The results from this work deepen our understanding of kinematic processes of reservoir and non-reservoir landslides, which is crucial for reasonable and effective landslide monitoring and prevention.

Process and numerical simulation of landslide sliding caused by permafrost degradation and seasonal precipitation

Process and numerical simulation of landslide sliding caused by permafrost degradation and seasonal precipitation

Potential failure mechanism and movement process of an ancient river-damming landslide in the SE Qinghai–Tibet Plateau

Potential failure mechanism and movement process of an ancient river-damming landslide in the SE Qinghai–Tibet Plateau

Engineering Geological and Geophysical Investigations to Characterise the Unstable Rock Slope of the Sopu Promontory (Gozo, Malta)

Different engineering geological and geophysical investigations were performed at the Sopu promontory in the island of Gozo (Malta), involved in an impressive lateral spreading process due to the superimposition of a stiff limestone (ULC) on a ductile clay (BC). The applied techniques include: traditional geological and engineering geological surveys, unmanned aerial vehicles (UAV) survey, electrical resistivity tomography (ERT) survey, ground-penetrating radar (GPR) investigations, single-station seismic ambient noise measurements, and array seismic ambient noise measurements. The integration of the obtained results allowed us to reconstruct a subsoil model of the promontory that includes features related to the local geology of the slope and to the landslide process, as well as to define a conceptual model that describes the main evolution phases of the expansion process. The presence of back-tilted rock blocks with no features of polarization of Rayleigh waves evidenced the different failure mechanism of the rigid UCL plateau at the Sopu promontory with respect to the Selmun promontory, located in the close island of Malta, where the lateral spreading due to the same geological setting tends to produce unstable rock blocks with a toppling mechanism. This result encourages further future observations and analyses of this topic.

Unmanned Aerial Vehicles (UAVs) in Landslide Investigation and Monitoring: A Review

Over the past decade, Unmanned Aerial Vehicles (UAVs) have emerged as essential tools for landslide studies, particularly in on-site investigations. This paper reviews UAV applications in landslide studies, with a focus on static geological characteristics, monitoring temporal and spatial dynamics, and responses post-events. We discuss the functions and limitations of various types of UAVs and sensors (RGB cameras, multi-spectral cameras, thermal IR cameras, SAR, LiDAR), outlining their roles and data processing methods in landslide applications. This review focuses on the UAVs’ roles in landslide geology surveys, emphasizing landslide mapping, modeling and characterization. For change monitoring, it provides an overview of the temporal and spatial evolution through UAV-based monitoring, shedding light on dynamic landslide processes. Moreover, this paper underscores UAVs’ crucial role in emergent response scenarios, detailing strategies and automated detection using machine learning algorithms. The discussion on challenges and opportunities highlights the need for ongoing UAV technology advancements, addressing regulatory hurdles, hover time limitations, 3D reconstruction accuracy and potential integration with technologies like UAV swarms.

Formation mechanism and dynamic process of open-pit coal mine landslides: a case study of the Xinjing landslide in Inner Mongolia, China

Formation mechanism and dynamic process of open-pit coal mine landslides: a case study of the Xinjing landslide in Inner Mongolia, China

Landslides, bedrock incision and human-induced environmental changes in an extremely rapidly formed tropical river gorge

Landslides are hillslope processes controlled by natural changing topographic conditions. Landslides are also influenced by human activities. Yet, understanding the space-time occurrence of landslides and their interactions with these typically long-term natural and short-term human-induced controls remains a key challenge in many regions, especially in tropical environments where data scarcity is commonplace. Here we decipher these dynamic processes in the Ruzizi Gorge located in the Kivu Rift (Central Africa), that is an exceptional geomorphological landmark whose origin is associated with the rerouting of >7000 km2 of drainage area from Lake Kivu during the Holocene. This bedrock river has also seen its landscape disturbed over the past decades by the development of the city of Bukavu (DR Congo). In this study, we combine detailed field observations, historical aerial photographs, archive analysis and satellite imagery to compile a multi-temporal inventory of 385 landslides and constrain their dynamics. We show that extremely high incision rates during the early stage of the formation of the gorge explain the space-time clustering of thousand-year-old large (up to ∼2 km2) landslides, independently from the lithological context. These landslides are currently non-active and poorly eroded. Their deposit areas partly cover the riverbed with boulders, armouring the channel and inhibiting further incision. The landslides that occurred over the last 60 years are shallower slope failures of smaller size and higher mobility. They tend to disappear rather quickly from the landscape, sometimes within a few years. Their distribution is primarily controlled by threshold slopes, lithology, and the past large landslides, the influence of the land use being less pronounced. Overall, the sediment mobilization rates associated with these high frequency landslides significantly outpace the extreme landslide erosion pulse associated with the gorge formation. Our results provide insight on interactions between channel-hillslope coupling and feedbacks among landslide processes and river gorge formation in a unique environment.

Structural and technological solutions for engineering and geological surveys, design and operation of buildings and structures on clay soils

The paper offers design and technological solutions and recommendations for engineering and geological surveys, as well as the design and operation of buildings and structures on clay soils in Stavropol. The existing experience of construction in engineering and geological conditions of specific soils and associated hazardous engineering and geological processes that influence the choice of engineering protection methods for new construction and reconstruction of existing buildings and structures has been studied. Clay soils in the city are characterized by swelling and shrinkage due to seasonal fluctuations in humidity in the upper part of the aeration zone, including in the flat areas of the city, and landslide processes on the slopes. When designing foundations for areas with swelling soils, it is crucial to consider the soil's ability to expand in volume as the humidity increases, known as swelling. In swelling soils, when the humidity decreases, the soil undergoes shrinkage. The paper also provides recommendations for water protection measures during the preparation of foundations for new construction. These measures primarily focus on addressing soil swelling rather than shrinkage. Structural and technological measures are presented to increase the rigidity and strength of buildings by dividing them into separate compartments with sedimentary seams, and introducing reinforced concrete continuous belts at several levels of the building.

Подверженность населенных пунктов Республики Дагестан обвально-осыпным процессам

The object of the study is the landslide activity in the Republic of Dagestan. The paper considers the results of systematization and analysis of various sources containing information on the activity and danger of landslide processes in the settlements of the republic for 2004–2022. The conditions, causes, activity and danger of landslide manifestations on their territory are characterized. The role of natural and man-made factors in the development of this process and its obvious timing to the winter-spring-summer period of the year (the time of snowmelt and abnormal precipitation) is determined. 46 settlements were identified (in 21 administrative districts of the republic), where significant landslides occurred over the period under consideration. Most of these rural settlements are located in the low and middle mountainous parts of the republic. The largest number of affected settlements (from the studied processes) are located in the Tsumadinsky and Akhvakhsky administrative districts of the republic. It is noted that in the period from 2004 to 2022, the greatest landslide activity was observed in 2014, and a very weak degree was observed in 2010, 2013 and 2021. In 2006, 2017 and 2019, landslides in the settlements of the republic were not recorded. The most catastrophic landslide processes over the studied period of time were observed in the villages of Hebda and Golotl in the Shamil district. The article provides information on the scale of the collapse deformations and destruction of residential infrastructure on the territory of settlements. The analysis of the socio-economic consequences of the landslide allows us to speak about a fairly significant degree of their danger to the life of the population in the mountainous part of the republic.

ПРИМЕНЕНИЕ МЕТОДОВ ИНЖЕНЕРНОЙ ГЕОФИЗИКИ ПРИ ОЦЕНКЕ ТЕХНИЧЕСКОГО СОСТОЯНИЯ СООРУЖЕНИЙ ИНЖЕНЕРНОЙ ЗАЩИТЫ ШАПСУГСКОГО ВОДОХРАНИЛИЩА

Purpose: to apply engineering geophysics methods based on the assessment of reliability parameters using non-destructive testing to identify the state of the engineering protection structures of the Shapsug reservoir. Materials and methods. The materials for the study were non-destructive testing data performed at different times of the year at the Shapsug reservoir, using “Oko-3” ground penetrating radar, “Pulsar-2.2” unit, Sokkia CX-105 total station, Nokta Invenio Smart and PSG-MG4 static action penetrometer. During the inspection, attention is drawn to the presence of such defects and damages as: violation of the geometric dimensions of the element or structure section; presence of deformation of an element or structure as a whole; formation and decompaction of the voids; landslide processes; visual dynamic damage; various cracks and the size of their opening; concrete and metal structures corrosion, etc. Results. The engineering-geophysical method for assessing the technical condition of the engineering protection structures of the Shapsug reservoir has been carried out. The state of the connection between earthworks and concrete structures and the temperature-sedimentation joints between concrete and reinforced concrete structures, affecting their stability, has been studied. Radiograms of collapse sites that arose as a result of accidents and were eliminated during the reconstruction of the dam were obtained. Conclusions. It was determined on the results obtained, that the geophysical complex makes it possible to study earthen low-head dams when determining various soil parameters, and most importantly, to identify the position and size of various defects inside the earth foundation of the dam. The identified difficulties were successfully resolved using a combined geophysical method, and the main problem is the compilation and adaptation of this method for a specific object.

Опасность оползневой деятельности в Моздокском районе Республики Северная Осетия – Алания

The object of the study is landslide activity in the Mozdok administrative region of the Republic of North Ossetia-Alania. The work examines the results of systematization and analysis of various sources containing information about the activity and danger of landslide processes in this area in the 21st century. The conditions, causes, activity and danger of landslide activations in the region are characterized. It is noted that the activity of landslide processes in the study area is mainly due to natural factors, however, recently the emergence of new landslide forms and the activation of old ones most often occur under technogenic influence. Landslide activity in the region is observed on the ledge of the right bank alluvial-accumulative terrace of the river. Terek, where most of the settlements of the region are located, as well as the northern slope of the Tersky ridge and in the area of the watershed ridge of the Sunzhensky ridge. The most significant activation of landslide processes (causing deformation of residential buildings and roadways of streets) was observed in the villages of Maly Malgobek, Predgornoye and Sukhotskoye. Since 2021, after the reconstruction of the Zilga – Mozdok highway, significant landslide deformations and destruction of the roadway have been observed on the section of the road between the villages of Khurikau (Mozdok district) and Old Batako (Right Bank district). The article provides information about the activity of landslide activity and the scale of deformations and destruction of residential and transport infrastructure that occurred in the area. Analysis of the socio-economic consequences of the landslide activations shows a significant degree of their danger to the life of the population in the Mozdok region.