Mass Movement Processes Research Articles

Landslides Susceptibility Assessment Based on GIS Statistical Bivariate Analysis in the Hills Surrounding a Metropolitan Area

In the highly populated analysed territory, the expansion of the construction zones and the pressure imposed on the slopes by the housing and transport infrastructure led to the appearance and reactivation of mass movement processes that affects the population and the environment. The purpose of this study consist in applying the principles of bivariate statistical analysis in order to determine the dynamic potential of a territory, taking into account the statistical relationship between the independent variables represented by predisposing and triggering factors of landslides (slope, geology, land use etc.) and dependent variables, in this case: landslides. The identification of the degree of validation of the results was determined by calculating the AUROC (Area under the Receiver Operating Characteristic) value, whose value of 0.854 highlights the representativeness of the chosen model. The analysis of landslides susceptibility highlights the inclusion of the territory represented by the hills surrounding Cluj-Napoca metropolitan area, Romania, on the classes of spatial occurrence of these processes.

Numerical simulation of the entrainment effect during mass movement in high-speed debris avalanches

Due to the actions from upper motion masses with high speed, impacting, scouring and shear failures may occur in the substrate materials, which can change the motion properties and increase the volume of the moving masses. How to simulate the entrainment effect during the mass movement process in a high-speed debris avalanche is an important topic in the research of landslide dynamics. A set of three-dimensional simulation models have been established to study the entrainment effect during the mass movement process. The RNG k-e turbulence model is used to simulate the motion of avalanche flow, and a substrate entrainment model is adopted to estimate the entrainment of substrate materials, which is an improved method to display the entrainment effect in high-speed debris avalanches. Sensitive analysis is applied to evaluate the mechanism parameters, and the velocity magnitude, entrainment, and deposition depth net change have all been discussed in detail. The computational results show that the gravitational energy is translated into kinetic energy with a variable velocity for the sliding masses after landslide initiated, and three stages occur in the sliding process: fragmentation, entrainment, and deposition. In addition, the parameters of viscosity, angle of repose, and entrainment coefficient play important roles in simulations of the entrainment process; the entrainment effect in a debris avalanche depends on not only the mechanical parameters but also the topographical conditions.

Distribution of shallow landslides and related mass movement processes induced by the heavy rain in July 2018 on Gogoshima Island, Ehime Prefecture, Japan

Distribution of shallow landslides and related mass movement processes induced by the heavy rain in July 2018 on Gogoshima Island, Ehime Prefecture, Japan

Multi-Source Glacial Lake Outburst Flood Hazard Assessment and Mapping for Huaraz, Cordillera Blanca, Peru

Filiacion institucional de autor: Alejo Cochachin Rapre / Autoridad Nacional del Agua - Unidad de Glaciologia y Recursos Hidricos (ANA-UGRH), Huaraz, Peru

Climatic and tectonic controls on source-to-sink processes in the tropical, ultramafic catchment of Lake Towuti, Indonesia

Humid tropical landscapes are subject to intense weathering and erosion, which strongly influence sediment mobilisation and deposition. In this setting, we aimed to understand how geomorphology and hydroclimate altered the style and intensity of erosion and sediment composition in a tropical lake and its tectonically active catchment. Lake Towuti (2.75°S, 121.5°E) is one of the oldest and deepest lakes in Indonesia, with uninterrupted lacustrine sedimentation over several glacial–interglacial cycles. Here we present results from a novel set of Lake Towuti surface sediment, bedrock and soil samples from the catchment, and two existing sediment cores that extend to 30,000 and 60,000 years before present. We studied the catchment morphology, soil properties, geochemistry, and clay and bulk mineralogy. Results from several river long profiles show clear signs of tectonic activity, which enhances river incision, favours mass movement processes, and together with remobilisation of fluvial deposits, strongly influences modern sedimentation in the lake. Material from the Mahalona River, the lake’s largest inflow, dominates modern sediment composition in Towuti’s northern basin. The river transports Al-poor and Mg-rich sediments (mainly serpentines) to the lake, indicating river incision into the Mg-rich serpentinised peridotite bedrock. Relatively small, but important additional contributions of material, come from direct laterite-derived input and the Loeha River, which both provide Al-rich and Mg-poor sediment to the lake. Over time, the Al/Mg and kaolinite-to-serpentine ratios varied strongly, primarily in response to lake-level fluctuations driven by hydroclimatic changes. In the past 60,000 years, both the Al/Mg and kaolinite-to-serpentine ratios showed variations sensitive to changes in climate boundary conditions across glacial-interglacial cycles, while tectonic activity had less influence on changes in sediment composition on these short time-scales.

Sackung and enigmatic mass movement folds on a structurally-controlled mountain ridge

The recently emerged concept of “slope tectonics” suggests that mass movement processes can produce structures similar in morphological expression to that of extensional, strike-slip and compressional tectonic deformations. Further, there has long been debate about the (tectonic or gravitational) origin of lineaments found on hillslopes. Here we present cases of where geological structure and inherited tectonic structures have preconditioned the development of mass movements and creation of slope tectonic features on a monoclinal ridge (Smrk Mt.) in the Outer Western Carpathians, Czechia. Geomorphic mapping from LiDAR-derived topography, structural measurements, electrical resistivity tomography and ground penetrating radar, were used to map synthetic and antithetic scarps, thrusts, and folds, and assess their relation to geological and tectonic structures. The scarps are found to be strongly related to transverse (NNW to NNE trending) inherited normal and strike-slip faults and mainly cross-cut the topography of the mountain ridge. Some of the folds are thought to have originated from buckling or compression in the distal parts of landslides. In other places, transpressional folds have developed oblique to major lateral shear surfaces interpreted to be sackung (mass movement scarps) that have been inherited from tectonic faults. The transpressional folds developed due to localized contraction along bends in the lateral shear surface as mass movement proceeded. Ramp-flat thrust folds developed in the compressional parts of landslides, where the landslide intersects with slope parallel sackung and/or inherited fault planes inclined to the slope. Altogether, this study demonstrates a connection between kinematics of deep-seated gravitational slope deformations (DSGSDs), shallower landslides and the origin of transpressive, ramp-flat thrust, and detachment structures in rock slopes.

Landslide inventory of the Basilicata region (Southern Italy)

ABSTRACTA 1:10,000 scale landslide inventory map has been prepared for the Basilicata region (southern Italy) through extensive geomorphological analyses based on aerial photo-interpretations and field surveys. The study area (about 8000 km2) includes different morpho-structural domains of the southern Italian Apennines, and our results suggest that mass movement processes are mainly related to the intrinsic fragility of the landscape, which is featured by high relief and widespread outcrops of clay-rich deposits. As a matter of fact, the landslides of the inventory map cover about 4.8% of the surface area of the Basilicata region, whereas the total percentage of the area covered by the landslides reaches a value of 7.7%, if one considers also the landslides surveyed in previous works.

A multi-factor approach for process-based seabed characterization: example from the northeastern continental margin of the Korean peninsula (East Sea)

This study investigates sediment transport and depositional processes from a newly collected dataset comprising sub-bottom chirp profiles, multibeam bathymetry, and sediment cores from the northeastern continental margin of Korea in the East Sea (Japan Sea). Twelve echo-types and eleven sedimentary facies have been defined and interpreted as deposits formed by shallow-marine, hemipelagic sedimentation, bottom current, and mass-movement processes. Hemipelagic sedimentation, which is acoustically characterized by undisturbed layered sediments, appears to have been the primary sedimentary process throughout the study area. The inner and outer continental shelf (<150 m water depth) have been influenced by shallow-marine sedimentary processes. Two slope-parallel canyons, 0.2–2 km wide and up to 30 km long, appear to have acted as possible conduits for turbidity currents from the shallower shelf into the deep basins. Bottom current deposits, expressed as erosional moats immediately below topographic highs, are prevalent on the southern lower slope at water depths of 400–450 m. Mass-movements (i.e., slides/slumps, debris flow deposits) consisting of chaotic facies characterize the lower slope and represent one of the most important sedimentary processes in the study area. Piston cores confirm the presence of mass-transport deposits (MTDs) that are characterized by mud clasts of variable size, shape, and color. Multibeam bathymetry shows that large-scale MTDs are chiefly initiated on the lower slope (400–600 m) with gradients up to 3° and where they produce scarps on the order of 100 m in height. Sandy MTDs also occur on the upper continental slope adjacent to the seaward edge of the shelf terrace. Earthquakes associated with tectonic activity and the development of fluid overpressure is considered as the main conditioning factor for destabilizing the slope sediments. Overall, the sedimentary processes show typical characteristics of a fine-grained clastic slope apron and change down-slope and differ within each physiographic province. Furthermore, the influence of geological inheritance (i.e., structural folds and faults) on geomorphology and sediment facies development is an important additional factor on the lower slopes. Together, these factors provide a rational basis for continental margin seabed characterization.

Landslides control the spatial and temporal variation of channel width in southern Taiwan: Implications for landscape evolution and cascading hazards in steep, tectonically active landscapes

AbstractIntense precipitation or seismic events can generate clustered mass movement processes across a landscape. These rare events have significant impacts on the landscape, however, the rarity of such events leads to uncertainty in how they impact the entire geomorphic system over a range of timescales. Taiwan is steep, tectonically active, and prone to landslide and debris flows, especially when exposed to heavy rainfall events. Typhoon Morakot made landfall in Taiwan in August of 2009, causing widespread landslides in southern Taiwan. The south to north trend in valley relief in southern Taiwan leads to spatial variability in landslide susceptibility providing an opportunity to infer the long‐term impact of such landslide events on channel morphology. We use pre‐ and post‐typhoon imagery to quantify the propagating impact of this event on channel width as the debris is routed through the landscape. The results show the importance of cascading hazards from landslides on landscape evolution based on patterns of channel width (both pre‐ and post‐typhoon) and hillslope gradients in 20 basins along strike in southern Taiwan. Prior to Typhoon Morakot, the river channels in the central part of the study area were about 3–10 times wider than the channels in the south. Following the typhoon, aggradation and widening was also a maximum in these central to northern basins where hillslope gradients and channel steepness is high, accentuating the pre‐typhoon pattern. The results further show that the narrowest channels are located where channel steepness is the lowest, an observation inconsistent with a detachment‐limited model for river evolution. We infer this pattern is indicative of a strong role of sediment supply, and associated landslide events, on long‐term channel evolution. These findings have implications across a range of spatial and temporal scales including understanding the cascade of hazards in steep landscapes and geomorphic interpretation of channel morphology. Copyright © 2018 John Wiley &amp; Sons, Ltd.

Thermal inertia variations from gully and mass-wasting activity in Gasa crater, Mars

Abstract Gasa crater has been the most active site observed on Mars to date, making it of particular interest for studying the process(es) behind gully formation and activity. In this study, we investigate whether differences in thermal inertia across different segments of gully systems, combined with morphological and colour observations with High-Resolution Imaging Science Experiment (HiRISE), can provide some constraints on the physical characteristics associated with recent activity within gullies in Gasa. We also investigate thermophysical differences between slopes in Gasa dominated by gully activity compared to those predominantly modified by dry mass-wasting processes. We find that Gasa crater exhibits clear variations in thermal inertia across its walls, controlled by the material properties and the types of dominant mass movement processes occurring on each wall. The youthful gully-fan lobes display thermal inertia values c. 20–40 J m −2 K −1 s −1/2 higher than adjacent older eroded and dust-covered lobes. The talus aprons from mass wasting in Gasa have thermal inertia values c. 60–80 J m −2 K −1 s −1/2 higher than gully aprons. The results of this study thus suggest that thermal imaging can inform us on surface change detection on Mars.

Sensitivity analysis of shallow planar landslides in residual soils on south Pennine hillslopes, Derbyshire, UK

Rainfall-induced shallow planar landslides on residual soil slopes are common mass movement processes on the southern Pennine slopes of Derbyshire, UK. They can be densely distributed across the region following intense rainfall events, frequently causing damage to infrastructure. This paper considers the results of slope stability sensitivity analyses using a simplistic Infinite Slope Stability Analysis (ISSA) model in shallow residual soils on the south Pennine hillslopes in Derbyshire. The results of the sensitivity analyses demonstrate how the factor of safety against shallow planar sliding changes as one geotechnical parameter is varied. An awareness of the variables involved in shallow planar translational landslides along with the knowledge of critical thresholds of certain geotechnical parameters establishes a basic context which assists the geotechnical engineer in the selection of key variables and making the correct engineering decisions in terms of remedial stabilisation solutions. The simple ISSA model used has limitations and recommendations are provided for improved field investigation methodology and modification of the simplistic ISSA model.

Badass gullies: Fluvio-mass-movement gully complexes in New Zealand's East Coast region, and potential for remediation

This paper reviews gully erosion in the East Coast region of New Zealand's North Island and conceptualises fluvio-mass-movement gully complexes as badass gully systems. Tectonic setting and lithological control, with steep slopes and a climate influenced by tropical cyclones, predispose hill country in the East Coast region to gully erosion. The clearance of indigenous forest since the late 1800s has dramatically increased catchment erosion and paved the way for development of large-scale fluvio-mass-movement gully complexes. These features are a composite of fluvial and mass movement processes. They are conceptualised as ‘badass’ by not conforming to any existing gully model and by generating disproportionate results in East Coast catchment sediment cascades. Their remediation is discussed, but their nature means that prevention is better than a cure.

Landslides and Fortified Settlements as Valuable Cultural Geomorphosites and Geoheritage Sites in the Moldavian Plateau, North-Eastern Romania

Today, as in the past, people living in hilly and mountainous regions have had to face the consequences of mass movement processes. Archaeological remains are important elements of cultural heritage, which can be significantly affected by landslides in different environmental settings and landscape evolution phases. In the Eastern Carpathians lowlands, landslides have shaped a landscape with inaccessible escarpments tens of metres high, providing ancient populations with naturally defensive sites at which to build their fortified settlements. In this study, we present a unique geoarchaeological context, the case of Chalcolithic and Thraco-Getic (6.5 ka BP to 2500 BP) fortified settlements, for which landslides provided a favorable geomorphologic setting for their construction. At the same time, however, landslides reamin as a permanent threat to the archaeological sites. In the Moldavian Plateau, North-Eastern Romania, more than 35 sites were identified on structural plateaus bounded by wide scarps of Pleistocene to Lower Holocene landslides, on cuesta ridges bounded by scarps of Holocene landslides, or situated on hillslopes, on erosional remnants of very old landslide bodies. For nine out of the 35 sites, we discuss and evaluate the geomorphosite status according to an indirect method developed by mixing a variety of methodologies illustrated in the literature, and we classify them as geomorphosites and specifically as cultural geomorphosites. The complex geomorphological, paleogeographical, and archaeological value of these proposed geosites allow us to argue for their geoheritage status. This situation requires a detailed analysis of landslide hazard and risk for these sites, since some have already been affected by landslides in the past, and especially when considering possible protection measures and actions to preserve and to include these geoheritage sites in the geotouristic networks of North-Eastern Romania.

Landslide inventory, Teziutlán municipality, Puebla, México (1942–2015)

ABSTRACTThis article describes the spatial distribution of landslides in Teziutlán, Puebla, Mexico, which has been historically affected by mass movement processes. The most significant disaster associated with landslides in October 1999. Rainfall-triggered landslides and floods caused more than 100 deaths in Teziutlán and economic losses of US$233 million in Sierra Norte de Puebla. A multi-temporal landslide inventory map (1:25,000) for the period 1942–2015 was constructed by means of field observation and the analysis and interpretation of aerial photographs and satellite images. The inventory map includes 662 landslides and covers 163 km2. The total landslide area is in the order of 0.71 km2. Taking into account the scarp, channel and depositional area, the mean surface of the landslides is 1075 m2. The largest documented area was 17,512 m2. The smallest landslide area mapped was 24 m2. Most movements can be considered as having been small.

Hazard assessment comparison of Tazhiping landslide before and after treatment using the finite-volume method

Abstract. Through investigation and analysis of geological conditions and mechanical parameters of the Tazihping landslide, finite-volume method coupling with Voellmy model is used to simulate the landslide mass movement process. The present paper adopts the numerical approach of the RAMMS software program and the GIS platform to simulate the mass movement process before and after engineering treatment. This paper also provides the conditions and characteristic variables of flow-type landslide in terms of flow height, velocity, and stresses. The 3-D division of hazard zones before and after engineering treatment was also mapped. The results indicate that the scope of hazard zones decreased after engineering treatment of the landslide. Compared with the case of before engineering treatment, the extent of high-hazard zones was reduced by about two-thirds, and the characteristic variables of the mass movement in the case of after treatment decreased to one-third of those in the case of before treatment. Despite having engineering treatment, the Tazhiping landslide still poses significant potential threat to the nearby residences. Therefore, it suggests that the houses located in high-hazard zones should be relocated or reinforced for protection.

An analysis of the supply process of loose materials to mountainous rivers and gullies as a result of dry debris avalanches

A dry debris avalanche will produce different volumes of colluviums or depositions (loose materials), which can have a significant impact on mountainous rivers or gullies. The loose material supply process caused by a debris avalanche is an important issue for understanding secondary disasters that form via the coupling of water flow and loose materials. Two flumes were designed for laboratory tests of the loose materials supply process to rivers/gullies, and the related impact factors were analyzed. Experimental results show that the supply of loose materials is a continuous process that directly relates to the avalanche’s mass movement processes. The sliding masses with smaller particle sizes are more sensitive to the flume slope and exhibited a longer supply time. The time-consuming for the debris avalanche travel in the flume decreased with the increasing particle size (such as flume B, time-consuming is decreased 0.2 s when the particle size increased from <1.0 to 20–60 mm), landslide volume and flume slope (flume A, consuming 1.6–2.1 s when flume slope is 29° decreased to consuming 1.3–1.5 s when flume slope is 41°), which means the increasing mobility of loose materials. The total supply time increased with the increasing landslide volume or decreasing particle size and flume slope. An empirical model for the process is presented based on numerous laboratory tests and numerical simulations, which can successfully describe the supply process for loose materials to a river/gully. The supply process of loose materials to mountainous gully from a dry debris avalanche is controlled by the material compositions of sliding masses, topographical conditions, landslide volume and bed friction, where large-volume debris avalanches that occur in mountainous river regions are more likely to obstruct the river flow and form a landslide-dammed lake.

Analysis of significance of environmental factors in landslide susceptibility modeling: Case study Jemma drainage network, Ethiopia

Aim of the paper is to describe methodology for calculating significance of environmental factors in landslide susceptibility modelingand present result of selected one. As a study area part of a Jemma basin in Ethiopian Highland is used. This locality is highly affected by mass movement processes. In the first part all major factors and their influence are described briefly. Majority of the work focuses on research of other methodologies used in susceptibility models and design of own methodology. This method is unlike most of the methods used completely objective, therefore it is not possible to intervene in the results. In article all inputs and outputs of the method are described as well as all stages of calculations. Results are illustrated on specific examples. In study area most important factor for landslide susceptibility is slope, on the other hand least important is land cover. At the end of article landslide susceptibility map is created. Part of the article is discussion of results and possible improvements of the methodology.

Periglacial cirque analogs: Elevation trends of cryoplanation terraces in eastern Beringia

Cryoplanation terraces are large erosional landforms common in cold, unglaciated mountainous environments. Terrace sequences are composed of alternating slope segments with gently sloping treads and steep rubble-covered risers, and culminate in extensive summit flats. Many unglaciated upland landscapes in eastern Beringia are dominated by these landforms. Indirect evidence indicates that they evolve through locally intensified weathering and mass-movement processes associated with late-lying snowcover. Geospatial analysis involving nearly 700 cryoplanation terraces in eastern Beringia demonstrates that their elevation rises from 175 to 350 masl on Bering Sea islands to median values >1200m near the Alaska-Canada border. The regional trends of cryoplanation terrace elevation are nearly identical to those of Wisconsinan cirques on several transects across Alaska. The consistency in the elevation trends of glacial cirques and cryoplanation terraces indicates close genetic links between the two classes of feature, involving topographic position, continentality gradients, and the mass balance of localized snow accumulations. Cryoplanation terraces can be considered the periglacial analogs of glacial cirques, and have greater potential as sources of paleoclimatic information than smaller periglacial features more sensitive to short-term climate variations. Process-oriented studies, age determinations, and high-resolution mapping are needed before the paleoenvironmental potential of these landforms can be realized fully.

Experimental investigation on the interaction between the rapid sliding body and exposed element

Laboratory experiments play a key role in establishing rapid sliding models, as they are conducive to providing similar conditions to those in actual mass movement processes and, most importantly, can be conducted repeatedly. In order to elucidate the mass movement mechanisms and assess the landslide intensity as well as the risk of exposed elements following rapid sliding body, laboratory experiments consisting of releasing dry rigid grains or ceramsite debris onto an oblique chute were designed. The intensity and the vulnerability values were evaluated for sand and ceramsite sliding body that impact a single building, a row of buildings, and a group of buildings, respectively. In addition, the sliding characteristics of the mass and the interaction process mechanisms between sliding solid debris and buildings were also able to be obtained. The results show that the velocity of the front-end sliding mass decreases with increasing of the number of buildings. In addition, the vulnerability value of exposed element and the safety distance could be calculated from the recorded data. However, detailed geological factors of the mass, which are also important factors in this experiment, were not taken into account in the model presented in this paper. Nonetheless, this model can be used as a powerful tool for evaluating landslide instability propagation mechanisms.

점봉산 산림습지의 지형·토양 환경분석 - 입도분석과 규조분석을 중심으로

This study is to provide basic data on ecology and morpho-pedo milieu by analyzing diatom and grain size of Mt. Jeombong forest wetland. Sample was collected from 6 points and named sample 943, 932, 885, 881A, 881b, 849. Sample 934 could not identify diatom, and the soil layer was colluvium deposited by mass-movement process. Layer of sample 932 was developed in the lower velocity environment, and presence frequence of complete diatom was very low. Hydrological situation of sample 855 was analysed in oligosaprobien environments. Sample 881A was meso-saprobic environments, velocity was slow area that inhabit musci bryopsida and sphaerocarpus. Sample 881B was acidic wetland in oligosaprobien environments. Sample 849 was analysed in oligosaprobien environments. The results of soil and diatom analysis are well reflect on wet environments of mountain wetlands and also it will expected to be in the help of environmental changes study of mountain wetlands.