Debris Slides Research Articles

Motion state recognition of debris ejected in vehicular collision after contact with the ground

The motion state of debris ejected from the vehicle involved in vehicular collision is important for finding out the vehicle collision speed. This research developed an analytical model to recognise the debris motion state. With the model, analyses were conducted, which reveal that if α, which is the contact angle between the debris and the ground at the moment when the debris collides the ground, is within the range from 0° to its boundary value, then the debris slides; if α is within the range from its boundary value to 90°, then the debris bounces. With debris' initial angular velocity ω = 0, the boundary value is 11.8° for sphere debris and 7.8° for rectangular debris; with ω ≠ 0, the boundary value for rectangular debris is arcsin(g / Rω2) where g represents the acceleration due to gravity and R is the distance from the debris centre to the point of its contact with the ground. Experiment tests were conducted for debris motion states with ω = 0, which confirmed the analytical results.

Morphology, age and sediment dynamics of the upper headwall of the Sahara Slide Complex, Northwest Africa: Evidence for a large Late Holocene failure

The Sahara Slide Complex in Northwest Africa is a giant submarine landslide with an estimated run-out length of ~900km. We present newly acquired high-resolution multibeam bathymetry, sidescan sonar, and sub-bottom profiler data to investigate seafloor morphology, sediment dynamics and the timing of formation of the upper headwall area of the Sahara Slide Complex. The data reveal a ~35-km wide upper headwall,opening towards the northwest, with multiple slide scarps, glide planes, plateaus, lobes, slide blocks and slide debris. The slide scarps were generated by retrogressive failure events associated with two types of mass movements: translational sliding and gravitational spreading. As a result of this evolution, three different glide planes (GP I, II, and III) can be distinguished approximately 100m, 50m and 20m below the seafloor. These glide planes are widespread and suggest failure along pronounced, continuous weak layers. Our data suggest an age of only about 2ka for the failure of the upper headwall area, a date much younger than that derived for landslide deposits on the lower reaches of the Sahara Slide Complex, which are dated at 50–60ka. The young age of the failure contradicts the postulate of a stable slope offshore Northwest Africa during sea-level highstands. Such an observation suggests that submarine-landslide risk along the continental margin of Northwest Africa should be reassessed based on a robust dating of proximal and distal slope failures.

Use of ROC curves for early warning of landslide displacement rates in response to precipitation (Piagneto landslide, Northern Apennines, Italy)

Active landslides are generally characterized by variations in displacement rate in response to cumulated precipitation. Velocities that are only exceeded in a limited number of days during the year might be considered as critical events, since they might determine, or prelude to, a significant evolution of the landslide. The purpose of this paper is to present a novel approach based on the use of receiver operating characteristic (ROC) curves for assessing cumulated precipitation thresholds that can provide early warning for the occurrence of critical events such as the exceedance of rare displacement rates. The approach has been developed and tested in the Piagneto landslide, an active complex rock slide—debris slide in the Northern Apennines of Italy, for which a 5-year continuous surveying monitoring dataset is available. On the basis of the first 4 years of monitoring data (training dataset), threshold curves relating cumulative precipitation (mm) to precipitation moving windows (days) have been generated by using different benchmarks that, in literature, are used to estimate the maximum predictive performance of ROC curves. These threshold curves have been successfully validated using the last 1 year of monitoring data (validation dataset). They have then been used to simulate how they might help defining different early warning levels in due advance. The proposed methodology can be replicated in any landslide for which a monitoring dataset that includes recurrent acceleration events in response to precipitation is available.

Gully recharge rates and debris flows: A combined numerical modeling and field-based investigation, Haida Gwaii, British Columbia

Rainfall, snowmelt and/or other mass movements are possible triggers to initiate debris flows. In supply-limited landscapes, clastic and organic materials (together termed debris) accumulate in the gully via various geomorphic processes that occur on gully sidewalls. The conceptualization of this phenomenon has been termed the gully recharge rate, with several recent field studies measuring such rates in coastal British Columbia. In the present study, a simple numerical model is introduced to estimate debris flow volumes in Haida Gwaii, British Columbia based on debris flow recurrence intervals, gully recharge rates and factors affecting deposition of debris flow material. Debris flow volumes obtained in model runs are somewhat lower than field-based values by about half, which is a reasonable result for this exploratory study. The annual erosion rate (clastic material) for debris flows in the model run is 0.031mmyr−1. This value is about 0.57× of the field-based value and is lower than the erosion rate for debris slides in Haida Gwaii of ~0.1mmyr−1. Deposition of debris flows in the model occurs in 60% of cases due to a decrease in channel gradient, with deposition resulting from high stream junction angles being less common. Locations for initiation of debris flow deposition were situated in stream orders 3 and 4 in 60% of cases. Sensitivity analysis shows that in comparison to other model variables, recharge rate has the greatest effect on the statistics and frequency distributions of debris flow volumes and total debris flow volume (summation of all debris activity in a basin) over the study time period.

Long‐range terrestrial laser scanning for geomorphological change detection in alpine terrain – handling uncertainties

AbstractLong‐range terrestrial laser scanning (TLS) is an emerging method for the monitoring of alpine slopes in the vicinity of infrastructure. Nevertheless, deformation monitoring of alpine natural terrain is difficult and becomes even more challenging with larger scan distances. In this study we present approaches for the handling of spatially variable measurement uncertainties in the context of geomorphological change detection using multi‐temporal data sets. A robust distance measurement is developed, which deals with surface roughness and areas of lower point densities. The level of detection (LOD), i.e. the threshold distinguishing between real surface change and data noise, is based on a confidence interval considering the spatial variability of TLS errors caused by large laser footprints, low incidence angles and surface roughness. Spatially variable positional uncertainties are modelled for each point according to its range and the object geometry hit. The local point cloud roughness is estimated in the distance calculation process from the variance of least‐squares fitted planes. Distance calculation and LOD assessment are applied in two study areas in the Eastern Alps (Austria) using multi‐temporal laser scanning data sets of slopes surrounding reservoir lakes. At Finstertal, two TLS point clouds of high alpine terrain and scanned from ranges between 300 and 1800 m are compared. At Gepatsch, the comparison is done between an airborne laser scanning (ALS) and a TLS point cloud of a vegetated mountain slope scanned from ranges between 600 and 3600 m. Although these data sets feature different conditions regarding the scan setup and the surface conditions, the presented approach makes it possible to reliably analyse the geomorphological activity. This includes the automatic detection of rock glacier movement, rockfall and debris slides, even in areas where a difference in vegetation cover could be observed. Copyright © 2016 John Wiley & Sons, Ltd.

Exploiting Maximum Entropy method and ASTER data for assessing debris flow and debris slide susceptibility for the Giampilieri catchment (north‐eastern Sicily, Italy)

AbstractThis study aims at evaluating the performance of the Maximum Entropy method in assessing landslide susceptibility, exploiting topographic and multispectral remote sensing predictors. We selected the catchment of the Giampilieri stream, which is located in the north‐eastern sector of Sicily (southern Italy), as test site. On 1 October 2009, a storm rainfall triggered in this area hundreds of debris flow/avalanche phenomena causing extensive economical damage and loss of life. Within this area a presence‐only‐based statistical method was applied to obtain susceptibility models capable of distinguishing future activation sites of debris flow and debris slide, which where the main source of failure mechanisms for flow or avalanche type propagation. The set of predictors used in this experiment comprised primary and secondary topographic attributes, derived by processing a high resolution digital elevation model, CORINE land cover data and a set of vegetation and mineral indices obtained by processing multispectral ASTER images. All the selected data sources are dated before the disaster. A spatially random partition technique was adopted for validation, generating 50 replicates for each of the two considered movement typologies in order to assess accuracy, precision and reliability of the models. The debris slide and debris flow susceptibility models produced high performances with the first type being the best fit. The evaluation of the probability estimates around the mean value for each mapped pixel shows an inverted relation, with the most robust models corresponding to the debris flows. With respect to the role of each predictor within the modelling phase, debris flows appeared to be primarily controlled by topographic attributes whilst the debris slides were better explained by remotely sensed derived indices, particularly by the occurrence of previous wildfires across the slope. The overall excellent performances of the two models suggest promising perspectives for the application of presence‐only methods and remote sensing derived predictors. Copyright © 2016 John Wiley & Sons, Ltd.

Mineralogical and Geochemical Control of Altered Andesitic Tuff upon Debris Slide Occurences at Pelangan Area, Southern Mountain of Lombok Island, Indonesia

Debris slides were recently found in the Pelangan area at Southern Mountain of Lombok Island, Indonesia. Pelangan is well known as the gold mineralization and hydrothermal alteration area. This study is aimed to identify the mineralogy and geochemistry of altered andesitic tuff that controlled slope instability and induced debris slides. For this purpose, it is necessary to prepare the field observation and laboratory analyses. Landslide inventory reveals that the Pelangan debris slides mostly occur in altered andesitic tuff. Based on the outcrop observations in the field, andesitic tuff found around the Pelangan debris slides have been altered in general. The strong intensity of alteration developed by hydrothermal alteration in this study area produces large amount of clay minerals especially montmorillonite, kaolinite, and illite. The abundance of those clay minerals reflect the intermediate argillic alteration. Montmorillonite is a type of clay mineral that easily swells at wet condition and easily shrinkages at dry condition. Swelling of clay mineral destroys intersheet and interlayer bonds, and reduces shear strength. The presence of clay minerals in the altered andesitic tuff of intermediate argillic zone can be considered as one of the factors that induced to the Pelangan debris slides. Further studies on geotechnical and slope stability analysis of the landslide area are crucial to be done for better understanding of the characteristics of the altered rocks inducing hazardous landslides.

A Study of Abrasive Wear on High Speed Steel Surface in Hot Rolling

In hot rolling, the thermal cyclic of work rolls causes a superficial oxide scale, which plays an important role on the contact friction and wear. The asperities of oxidised strip surface and wear debris slide over the High Speed Steel (HSS) work roll surface which comprises of hard carbides within an iron matrix under high pressure and velocity. Abrasive wear occurs and the particles will be removed from HSS surface. The current study introduces the Discrete Element Method (DEM) to investigate this abrasive wear phenomenon. The model successfully provides a physically based abrasive roll wear predication of HSS work roll with the consideration of carbides and oxide layers. It has been found that the carbide shape in the HSS roll affects the wear significantly, which has not been reported by previous numerical simulations and is the main focus of this research.

Deterministic approach for susceptibility assessment of shallow debris slide in the Darjeeling Himalayas, India

High magnitude rainfall triggers numerous shallow debris slides in the Darjeeling Himalayas causing widespread damage to the environment, loss of life and property. Thin soil cover and steep topography make the region vulnerable to debris slides. The objective of the present study is to assess the susceptibility of the eastern part of Darjeeling Himalayas (covering about 330km2) to shallow debris slides through the functional relationship of hillslope hydrology and mechanical properties of slope materials. Deterministic approach-based shallow landsliding stability (SHALSTAB) model following Mohr–Coulomb failure law was adopted to assess landslide susceptibility. Topographical parameters were derived from 8-m resolution Cartosat-1 digital elevation model (DEM) and mechanical properties of soil were obtained from an analysis of 15 soil samples. For slope stability assessment, the topographical and soil parameters were put into three different scenarios — (i) assuming the surface entirely free from vegetation (Model-1), (ii) involving the role of vegetation root cohesion (Model-2) and (iii) surcharge of vegetation, buildings and other structures along with root cohesion (Model-3). These predictive models were used to classify the area into various susceptibility classes with specific amounts of critical rainfall (Qc). The result shows that 28%, 9% and 10% of the study area come under unconditionally unstable class in the three models, respectively. About 22% land in Model-1 and 42% in each Model-2 and Model-3 come under unconditionally stable class. Protective capacity of roots against debris slide played a significant role in Model-2 and Model-3. Performance of models was validated by comparison of observed–predicted landslide areas and the area under the receiver operating characteristic (ROC) curve. It is found that the overall success rate of all the three models is relatively low (56.60% to 64.50%). Thus, it may be concluded that the SHALSTAB model in assessing landslide should either not be used at all at a regional level in the Himalayas or be used only with great caution along with additional field and lab data.

A Numerical Hazard Rating Method for Debris Slide Susceptibility Mapping in Turkana, Kenya

This study presents a numerical rating method for mapping debris slide susceptibility in Turkana, Kenya. The use of remotely sensed data; 31 m digital elevation model (DEM) 1.5 m SPOT 6 image of study area, and an exploratory soil and agro-climatic zone map of Kenya, (1:1,000,000) were adopted. Numerical hazard rating scheme for testing relationship between debris slide and five event controlling parameters; slope angle, friction angle of soil, soil drainage, soil thickness and proximity to drainage is described. Corresponding thematic data layers were generated for these parameters in ArcGIS. Numerical hazard ratings were assigned to these parameters on a scale of 0 – 5 with 0 being the least susceptible class and 5 having the greatest susceptibility to debris slide. These hazard ratings were justified with the use of the Coulomb Equation of stability analysis. Debris slide susceptibility map indicates that areas close to drainage channels had the highest susceptibility value ranging from 3 – 5. On the hand, areas with no surface material, i.e., bedrock outcrop, and low slope angles had minimal susceptibility value of zero (0). There was no landslide data for the study area and hence the debris slide susceptibility map could not be validated. This study therefore has developed a method for debris slide susceptibility assessment that can be adopted in an inaccessible terrain, or in an environment with no landslide data.

Geomorphology of the huge Hinlopen–Yermak landslide on the northern Svalbard margin

Submarine landslide scars, including the huge Hinlopen–Yermak slide-scar north of Svalbard (Fig. 1) (Vanneste et al. 2006; Winkelmann et al. 2006), are relatively common geomorphological features on glaciated continental margins. However, landslide characteristics, for example scar area, run-out and displaced volume, vary significantly (Hogan et al. 2013). A key pre-condition for failure is rapid deposition of mainly diamictic glacier-derived sediment on the slope during full-glacials, alternating with fine-grained interglacial deposition. This layered architecture, and the varying geotechnical properties of the debris, facilitate downslope mass-movements with a variety of possible triggers. Fig. 1. Marine geophysical data over Hinlopen–Yermak landslide scar, northern Svalbard. ( a ) Multibeam image showing slide scar. PR, arcuate pressure ridges. DR, detached sediment ridges. Acquisition systems Kongsberg EM300. Frequency 30 kHz (RV Jan Mayen ). Hydrosweep DS2. Frequency 15.5 kHz (RV Polarstern ). Kongsberg EM120. Frequency 12 kHz (RSS James Clark Ross ). Grid-cell size 100 m. ( b ) Seismic-reflection profile of slide headwall and post-slide sediment fill. Acquisition system two 40 cubic inch airguns. VE×6. ( c ) Bathymetric image of the complex eastern headwall area showing detached sediment ridges (DR and inset; VE×7) and blocky debris (BD) on slip planes. ( d ) Bathymetric image of rafted mega-blocks within slide debris. Ridges of material pushed up …

The establishment of rainfall thresholds for debris slide in Taiwan - with the combination of multivariate analysis and the I-R index

The establishment of rainfall thresholds for debris slide in Taiwan - with the combination of multivariate analysis and the I-R index

Permeability and pressure measurements in Lesser Antilles submarine slides: Evidence for pressure‐driven slow‐slip failure

AbstractRecent studies hypothesize that some submarine slides fail via pressure‐driven slow‐slip deformation. To test this hypothesis, this study derives pore pressures in failed and adjacent unfailed deep marine sediments by integrating rock physics models, physical property measurements on recovered sediment core, and wireline logs. Two drill sites (U1394 and U1399) drilled through interpreted slide debris; a third (U1395) drilled into normal marine sediment. Near‐hydrostatic fluid pressure exists in sediments at site U1395. In contrast, results at both sites U1394 and U1399 indicate elevated pore fluid pressures in some sediment. We suggest that high pore pressure at the base of a submarine slide deposit at site U1394 results from slide shearing. High pore pressure exists throughout much of site U1399, and Mohr circle analysis suggests that only slight changes in the stress regime will trigger motion. Consolidation tests and permeability measurements indicate moderately low (~10−16–10−17 m2) permeability and overconsolidation in fine‐grained slide debris, implying that these sediments act as seals. Three mechanisms, in isolation or in combination, may produce the observed elevated pore fluid pressures at site U1399: (1) rapid sedimentation, (2) lateral fluid flow, and (3) shearing that causes sediments to contract, increasing pore pressure. Our preferred hypothesis is this third mechanism because it explains both elevated fluid pressure and sediment overconsolidation without requiring high sedimentation rates. Our combined analysis of subsurface pore pressures, drilling data, and regional seismic images indicates that slope failure offshore Martinique is perhaps an ongoing, creep‐like process where small stress changes trigger motion.

Investigation of Geomorphic and Seismic Effects on the 1959 Madison Canyon, Montana, Landslide Using an Integrated Field, Engineering Geomorphology Mapping, and Numerical Modelling Approach

We present an integrated approach to investigate the seismically triggered Madison Canyon landslide (volume = 20 Mm3), which killed 26 people in Montana, USA, in 1959. We created engineering geomorphological maps and conducted field surveys, long-range terrestrial digital photogrammetry, and preliminary 2D numerical modelling with the objective of determining the conditioning factors, mechanisms, movement behaviour, and evolution of the failure. We emphasise the importance of both endogenic (i.e. seismic) and exogenic (i.e. geomorphic) processes in conditioning the slope for failure and hypothesise a sequence of events based on the morphology of the deposit and seismic modelling. A section of the slope was slowly deforming before a magnitude-7.5 earthquake with an epicentre 30 km away triggered the catastrophic failure in August 1959. The failed rock mass rapidly fragmented as it descended the slope towards Madison River. Part of the mass remained relatively intact as it moved on a layer of pulverised debris. The main slide was followed by several debris slides, slumps, and rockfalls. The slide debris was extensively modified soon after the disaster by the US Army Corps of Engineers to provide a stable outflow channel from newly formed Earthquake Lake. Our modelling and observations show that the landslide occurred as a result of long-term damage of the slope induced by fluvial undercutting, erosion, weathering, and past seismicity, and due to the short-term triggering effect of the 1959 earthquake. Static models suggest the slope was stable prior to the 1959 earthquake; failure would have required a significant reduction in material strength. Preliminary dynamic models indicate that repeated seismic loading was a critical process for catastrophic failure. Although the ridge geometry and existing tension cracks in the initiation zone amplified ground motions, the most important factors in initiating failure were pre-existing discontinuities and seismically induced damage. Amplification played a secondary role.

Effectiveness of visually analyzing LiDAR DTM derivatives for earth and debris slide inventory mapping for statistical susceptibility modeling

Landslide inventories are the most important data source for landslide process, susceptibility, hazard, and risk analyses. The objective of this study was to identify an effective method for mapping a landslide inventory for a large study area (19,186 km2) from Light Detection and Ranging (LiDAR) digital terrain model (DTM) derivatives. This inventory should in particular be optimized for statistical susceptibility modeling of earth and debris slides. We compared the mapping of a representative set of landslide bodies with polygons (earth and debris slides, earth flows, complex landslides, and areas with slides) and a substantially complete set of earth and debris slide main scarps with points by visual interpretation of LiDAR DTM derivatives. The effectiveness of the two mapping methods was estimated by evaluating the requirements on an inventory used for statistical susceptibility modeling and their fulfillment by our mapped inventories. The resulting landslide inventories improved the knowledge on landslide events in the study area and outlined the heterogeneity of the study area with respect to landslide susceptibility. The obtained effectiveness estimate demonstrated that none of our mapped inventories are perfect for statistical landslide susceptibility modeling. However, opposed to mapping polygons, mapping earth and debris slides with a point in the main scarp were most effective for statistical susceptibility modeling within large study areas. Therefore, earth and debris slides were mapped with points in the main scarp in entire Lower Austria. The advantages, drawbacks, and effectiveness of landslide mapping on the basis of LiDAR DTM derivatives compared to other imagery and techniques were discussed.

The Interaction Between Insect Outbreaks and Debris Slides in a Glacial Valley of the Eastern Canadian Shield

Disturbance interactions, including compound and linked disturbances, are increasingly recognized to have important effects on landscape structure and function. Most research on linked disturbances has focused on the interaction between insect outbreaks and fire, and between fire or forest harvesting and other physical processes such as soil erosion and landslides, but to our knowledge, none have explored the possible interaction between insect outbreaks and landslides. We tested the hypothesis that severe outbreaks of the spruce budworm, an insect defoliator, could increase the probability of debris slide occurrence in the southern boreal forest of eastern Canada. We mapped 28 debris slides that occurred between 1996 and 2002 along a deep U-shaped glacial valley (Jacques-Cartier River valley, Quebec) and compared their characteristics with those of 50 random sites unaffected by debris slides using maps of the abiotic (topography, surficial deposits, and so on) and biotic (forest cover and cumulative spruce budworm defoliation from aerial surveys) factors that could influence the probability of debris slide occurrence. Logistic regression showed that probability of debris slide occurrence increased with mean slope, outbreak severity, and abundance of balsam fir, and that it was associated with thin surficial deposits and northeast aspects. Spruce budworm outbreaks probably increase susceptibility to debris slides primarily by reducing the biomass of soil-stabilizing root systems, and possibly also by reducing forest transpiration, which in turn increases soil water content. Future research should focus on the mechanisms underlying insect outbreak-landslide interactions.

Revision of the conodont zonation of the uppermost Hwajeol Formation (Furongian), Taebaeksan Basin, Korea

The uppermost interval of the Hwajeol Formation, Taebaeksan Basin, has been assigned to the Fryxellodontus inornatus-Monocostodus sevierensis-Semiacontiodus lavadamensis Zone. The main species in the zone are Fryxellodontus inornatus Miller, Hirsutodontus hirsutus Miller, Monocostodus sevierensis (Miller), Semiacontiodus lavadamensis (Miller), S. nogamii Miller, Utahconus utahensis (Miller), and Cordylodus proavus Muller. These species were re-examined to evaluate the biostratigraphy of the Bangteogol and Maesangol sections. Data were added from eleven sections around the Taebaeksan Basin, which were studied previously by the first author. Conodont occurrences above the Cambrooistodus minutus Zone are characterized by a lack of vertical and lateral continuity in sections. Conodont recovery is relatively poor but is sufficient for biostratigraphic assignment. This trend of conodont occurrence seems to be related to sedimentary process, including debris slides and eustatic sea-level fluctuation. Nevertheless, detailed study of the characteristic species of the zone leads to the conclusion that retention of the zone is reasonable. However, it is renamed the M. sevierensis-S. lavadamensis Zone because Fryellodontus inornatus occurs stratigraphically lower than the other two nominate species. The M. sevierensis-S. lavadamensis Zone is correlated with equivalent zones of western USA, Canada, North China, and Australia.

Post-wildfire debris flows in southern British Columbia, Canada

Several post-wildfire debris flows and other landslides occurred after the extreme wildfire season of 2003 in the southern interior of British Columbia. Such events had not been previously reported in Canada, although they are common in lower latitudes. Severe wildfire seasons also were experienced in 2007 and 2009, and additional events were observed in four fires. Post-wildfire landslides have occurred in spring, summer and fall (autumn); events have been triggered by spring snowmelt, high-intensity summer rainstorms and low-intensity fall rainstorms. Of a total of 36 documented events, 23 were debris flows, and the most common initiating mechanism was high peak flow in channels. Most sediment in these events was derived from the channels, not from erosion in burned areas. Seven of the events were infiltration-triggered debris slides, and six events were debris floods. A variety of hydrologic changes can contribute to the prevalence of post-wildfire landslides and floods, including an increase in snowmelt rate. High-severity burn in catchment headwaters above steep channels is a topographic factor favouring debris flow occurrence. These observations demonstrate that the likelihood of debris flows and other mass-movement events in susceptible terrain is significantly increased following severe wildfire in this snow-dominated environment.

The Friulian-Venetian Basin I: architecture and sediment flux into a shared foreland basin

In the northern Italian Alps, along the Tagliamento River valley (46°23'49 N, 12°42'51 E), a large deep-seated landslide affects a road tunnel near Passo della Morte, along National Road 52 Carnica. Several secondary phenomena are developing on the unstable slope, as rock block slides and shallow debris slides. This work focuses on the creation of a geological and numerical model able to simulate the displacements of two adjacent and partly superimposed shallow landslides, which are damaging the east entrance of the tunnel. In fact, field surveys and long-term monitoring allowed the geometries and the kinematics of the landslide bodies to be defined with great detail. In this phase, a numerical model is needed in order to evaluate the effectiveness of possible structural mitigation works. The complexity of the landslides dynamics and the different rates of activity suggest to set up a 3D model rather than a 2D one, using the commercial software FLAC3D. A helicopter-borne Light Detection And Ranging (LiDAR) survey allowed to rely on a 1 m Digital Terrain Model (DTM) for surface topography, while several boreholes equipped with inclinometers supported the definition of a 3D sliding surface. However, the high resolution of the input data collides with the necessity of reduce computational time to an acceptable level, thus an interpolation of the spatial data was almost compulsory. Anyhow, the calibrated model of the Passo della Morte landslides, obtained with filtered data, is the starting point for the simulation of different types of possible countermeasure works designed to mitigate landslide risk.

Delayed landscape responses to historical interventions: Tipu Sultan’s smelters and recent landslides

The Western Ghats in southwest India bear testimony to frequent landslides, especially during the monsoon season, causing widespread loss of life and property. The landslides occur during the monsoon season and include debris flow, debris slide, debris avalanches, rock falls, rock slips, slumps, creeps, etc. Here, we report a finding, that requires elaborate study: a recent landslide occurred at an ancient iron ore works, but did not take place in the usual monsoon season. Such failures are concentrated in and around areas where banded iron formations (BIFs) are present. These subsurface cavities are a menace to the public, especially when construction activities are taking place.