deep seated gravitational slope deformations related landslides and tectonics abstract deep seated gravitational slope deformations and their relationships with tectonic deformation of rocks is considered to examine the viewpoint of tectonics as a causative factor in slope deformation first a distinction is made between the different types of deep seated gravitational slope deformation then the geomorphological and structural effects of the different macrostructural deformations induced by tectonics on the scale of the whole deforming ridge is briefly discussed finally some case studies that represent either verified or possible cases of gravity deformation in response to tectonic activity are used as illustration

identification of neolithic to modern erosion sedimentation phases using geochemical approach in a loess covered sub catchment of south moravia czech republic abstract a colluvial soil with a 380 cm deep humus enriched horizon was studied in a loess region of south moravia czech republic which is characterized by a strong soil material re deposition distribution of soil properties within the colluvial soil profile was used for distinguishing the different sedimentation phases and understanding colluvial soil formation the colluvial profile is stratified into different horizons distinguishable by a specific distribution of basic soil properties soil organic carbon content carbonate content or soil reaction in the profile low organic carbon content 0 6 0 8 and increased carbonate content up to 8 in the upper 260 cm indicates a rapid change of the soil cover and significant admixture of loess parent material in the sediment an abrupt increase of organic carbon content 2 and no carbonates between 300 and 380 cm is evidence of a buried chernozem at this depth antropogenically induced substances such as pesticide residues or increased nutrient content connected to agricultural practices enables the detection of sedimentation periods the peak ddt content up to 0 04 mg kg at the depth of 50 150 cm clearly delineates the material sedimented in the 1950s 1970s and material sedimented in earlier or later stages the same trend can be traced in phosphorus and potassium content given by intensive use of fertilizers at a given time period the potential use of lead and cadmium as another indicator of anthropogenic influence at some stage of soil sedimentation was not proven due to their low concentration in the colluvial profile three phases of soil erosion and sedimentation were distinguished each reflecting different land use and intensity of agriculture the highest amount of soil material 2 m deposited in the colluvial profile can be attributed to the last and shortest erosional phase corresponding to intensive agriculture and massive land consolidation in the last 70 years

predictive uncertainty of peak outflow relations for landslides dam breach risk assessment development considering the failure of landslide dams often requires the estimation of peak outflow through the breach the empirical equations based on data from case studies tend to be the first direct approach this paper conducted an uncertainty analysis when these empirical relations were utilized to predict the peak outflow of a breached landslide dam the results suggest that the relations derived from manmade dams or embankments typically overestimate the peak outflow about 1 5 to 3 4 of an order of magnitude and the relations derived from the database of landslide dams have much smaller mean prediction errors and also exhibit broad uncertainty bands application of the uncertainly analysis was illustrated by the tangjiashan landslide dammed lake formed during 2008 wenchuan earthquake in addition the predicted results from eq 1 deduced herein were considered to be the reliable estimate of peak outflow through the breach of landslide dam

why so few landslides triggered by the 2002 denali earthquake alaska abstract the 2002 m w 7 9 denali fault earthquake alaska provides an unparalleled opportunity to investigate in quantitative detail the regional hillslope mass wasting response to strong seismic shaking in glacierized terrain we present the first detailed inventory of 1580 coseismic slope failures out of which some 20 occurred above large valley glaciers based on mapping from multi temporal remote sensing data we find that the denali earthquake produced at least one order of magnitude fewer landslides in a much narrower corridor along the fault ruptures than empirical predictions for an m 8 earthquake would suggest despite the availability of sufficiently steep and dissected mountainous topography prone to frequent slope failure in order to explore potential controls on the reduced extent of regional coseismic landsliding we compare our data with inventories that we compiled for two recent earthquakes in periglacial and formerly glaciated terrain i e at yushu tibet m w 6 9 2010 and aysen fjord chile 2007 m w 6 2 fault movement during these events was similarly to that of the denali earthquake dominated by strike slip offsets along near vertical faults our comparison returns very similar coseismic landslide patterns that are consistent with the idea that fault type geometry and dynamic rupture process rather than widespread glacier cover were among the first order controls on regional hillslope erosional response in these earthquakes we conclude that estimating the amount of coseismic hillslope sediment input to the sediment cascade from earthquake magnitude alone remains highly problematic particularly if glacierized terrain is involved

simulated effect of soil depth and bedrock topography on near surface hydrologic response and slope stability this paper explores the effect of hillslope hydrological behavior on slope stability in the context of transient subsurface saturation development and landslide triggering we perform a series of virtual experiments to address how subsurface topography affects the location and spatial pattern of slip surface development and pore pressure dynamics we use a 3d darcy richards equation solver hydrus 3 d combined with a cellular automata slope stability model to simulate the spatial propagation of the destabilized area our results showed that the soil bedrock interface and in particular bedrock depressions played a key role in pore pressure dynamics acting as an impedance for the downslope drainage of perched water filling and spilling of depressions in the bedrock surface microtopography induced localized zones of increased pressure head such that the development of pore pressure fields not predictable by surface topography lead to rapid landslide propagation our work suggests that landslide models should consider the subsurface topography in order to include a connectivity component in the mathematical description of hydrological processes operating at the hillslope scale copyright 2012 john wiley sons ltd

the dating of bedrock landslide reactivations using dendrogeomorphic techniques the mazak landslide outer western carpathians czech republic landslides predisposed by the anisotropy of flysch bedrock are typical features of mass movements affecting the outer western carpathians a dendrogeomorphic investigation involving an extensive dendrometric n 1680 survey and tree ring analysis of 176 norway spruce trees picea abies l karst was used to reconstruct the spatial and temporal activity of the mazak landslide situated in the highest part of the czech outer western carpathians as revealed by geomorphic analysis and electrical resistivity tomography the landslide is a translational medium depth 30 m bedrock feature originating at the intersection of inclined bedding planes with diagonal nw nnw striking and longitudinal ne striking sets of joints and faults a tree ring analysis shows nine major landslide years 1929 1940 1949 1960 1972 1980 1985 1997 2000 accompanied by six additional years with minor reactivations 1933 1945 1955 1958 1977 1996 during the past hundred years 1912 2011

a procedure for landslide susceptibility zonation by the conditional analysis method numerous methods have been proposed for landslide probability zonation of the landscape by means of a geographic information system gis among the multivariate methods i e those methods which simultaneously take into account all the factors contributing to instability the conditional analysis method applied to a subdivision of the territory into unique condition units is particularly straightforward from a conceptual point of view and particularly suited to the use of a gis in fact working on the principle that future landslides are more likely to occur under those conditions which led to past instability landslide susceptibility is defined by computing the landslide density in correspondence with different combinations of instability factors the conceptual simplicity of this method however does not necessarily imply that it is simple to implement especially as it requires rather complex operations and a high number of gis commands moreover there is the possibility that in order to achieve satisfactory results the procedure has to be repeated a few times changing the factors or modifying the class subdivision to solve this problem we created a shell program which by combining the shell commands the gis geographical research analysis support system grass commands and the gawk language commands carries out the whole procedure automatically this makes the construction of a landslide susceptibility map easy and fast for large areas too and even when a high spatial resolution is adopted as shown by application of the procedure to the parma river basin in the italian northern apennines

the formation and failure of natural dams of the numerous kinds of dams that form by natural processes dams formed from landslides glacial ice and late neoglacial moraines present the greatest threat to people and property landslide dams form in a wide range of physiographic settings the most common types of mass movements that form landslide dams are rock and debris avalanches rock and soil slumps and slides and mud debris and earth flows the most common initiation mechanisms for dam forming landslides are excessive rainfall and snowmelt and earthquakes landslide dams can be classified into six categories based on their relation with the valley floor type i dams 11 of 184 landslide dams from around the world that we were able to classify do not reach from one valley side to the other type ii dams 44 span the entire valley floor in some cases depositing material high on opposite valley sides type iii dams 41 move considerable distances both upstream and downstream from the landslide failure type iv dams 1 are rare and involve the contemporaneous failure of material from both sides of a valley type v dams 1 also are rare and are created when a single landslide sends multiple tongues of debris into a valley and forms two or more landslide dams in the same reach of river type vi dams 3 involve one or more failure surfaces that extend under the stream or valley and emerge on the opposite valley side many landslide dams fail shortly after formation in our sample of 73 documented landslide dam failures 27 of the landslide dams failed less than 1 day after formation and about 50 failed within 10 days over topping is by far the most common cause of failure the timing of failure and the magnitude of the resulting floods are controlled by dam size and geometry material characteristics of the blockage rate of inflow to the impoundment size and depth of the impoundment bedrock control of flow and engineering controls such as artificial spill ways diversions tunnels and planned breaching by blasting or conventional excavation glacial ice dams can produce at least nine kinds of ice dammed lakes the most dangerous are lakes formed in main valleys dammed by tributary glaciers failure can occur by erosion of a drainage tunnel under or through the ice dam or by a channel over the ice dam cold polar ice dams generally drain supraglacially or marginally by downmelting of an outlet channel warmer temperate ice dams tend to fail by sudden englacial or subglacial breaching and drainage late neoglacial moraine dammed lakes are located in steep mountain areas affected by the advances and retreats of valley glaciers in the last several centuries these late neoglacial dams pose hazards because 1 they are sufficiently young that vegetation has not stabilized their slopes 2 many dam faces are steeper than the angle of repose 3 these dams and lakes are immediately downslope from steep crevassed glaciers and near vertical rock slopes and 4 downstream from these dams are steep canyons with easily erodible materials that can be incorporated in the flow and increase flood peaks the most common reported failure mechanism is overtopping and breaching by a wave or series of waves in the lake generated by icefalls rockfalls or snow or rock avalanches melting of ice cores or frozen ground and piping and seepage are other possible failure mechanisms natural dams may cause upstream flooding as the lake rises and downstream flooding as a result of failure of the dam although data are few for the same potential energy at the dam site ownstream flood peaks from the failure of glacier ice dams are smaller than those from landslide moraine and structed earth fill and rock fill dam failures moraine dam failures appear to produce some of the largest downstream flood peaks for potential energy at the dam site greater than 1011 1012 joules differences in flood peaks natural dam failures appear to be controlled by dam characteristics and failure mechanisms

climatic and geometric controls on the global distribution of surge type glaciers implications for a unifying model of surging financial support was provided by the conocophillips lundin northern area program project crios

discriminant analysis of the geomorphic characteristics and stability of landslide dams article i nfo landslides can cause the formation of dams but these dams often fail soon after lake formation thus rapidly evaluating the stability of a landslide dam is crucial for effective hazard mitigation this study utilizes discriminant analysis based on a japanese dataset consisting of 43 well documented landslide dams to determine the significant variables including log transformed peak flow or catchment area and log transformed dam height width and length in hierarchical order which affect the stability of a landslide dam the high overall prediction power 88 4 of the 43 training cases are correctly classified and the high cross validation accuracy 86 demonstrate the robustness of the proposed discriminant models phwl with variables including log transformed peak flow and log transformed dam height width and length and ahwl with variables including log transformed catchment area and log transformed dam height width and length compared to a previously proposed dbi index based graphic approach the discriminant model ahv which uses the log transformed catchment area dam height and dam volume as relevant variables shows better ability to evaluate the stability of landslide dams although these discriminant models are established using a japanese dataset only the present multivariate statistical approach can be applied for an expanded dataset without any difficulty when more completely documented worldwide landslide dam data are available

climate physiographically differentiated pan european landslide susceptibility assessment using spatial multi criteria evaluation and transnational landslide information abstract with the adoption of the eu thematic strategy for soil protection in 2006 small scale 1 1 m assessments of threats affecting soils over europe received increasing attention as landslides have been recognized as one of eight threats requiring a pan european evaluation we present an approach for landslide susceptibility evaluation at the continental scale over europe unlike previous continental and global scale landslide susceptibility studies not utilizing spatial information on the events we collected more than 102 000 landslide locations in 22 european countries these landslides are heterogeneously distributed over europe but are indispensable for the evaluation and classification of pan european datasets used as spatial predictors and the validation of the resulting assessments for the analysis we subdivided the european territory into seven different climate physiographical zones by combining morphometric and climatic data for terrain differentiation and adding a coastal zone defined as a 1 km strip inland from the coastline landslide susceptibility modeling was performed for each zone using heuristic spatial multicriteria evaluations supported by analytical hierarchy processes and validated with the inventory data using the receiver operating characteristics in contrast to purely data driven statistical modeling techniques our semi quantitative approach is capable to introduce expert knowledge into the analysis which is indispensable considering quality and resolution of the input data and incompleteness and bias in the inventory information the reliability of the resulting susceptibility map elsus 1000 version 1 1 km resolution was examined on an administrative terrain unit level in areas with landslide information and through the comparison with available national susceptibility zonations these evaluations suggest that although the elsus 1000 is capable for a correct synoptic prediction of landslide susceptibility in the majority of the area it needs further improvement in terms of data used

discharges of turbid water during mini surges of variegated glacier alaska u s a discharges of water sediment and dissolved impurities from variegated glacier ala ska were monitored in the early summers of 1980 and 1981 during the occurrence of mini surg es sea sonal trends weat her related eve nts and diurnal variat ions similar to behavior of other temperat e gl acier streams were found the prin cipal effect in the stream associated with mini surge occurrence was a brief discharge of extremely turbi d water the turbidity is assumed to be introduced into the basal hydraulic system by initiation of the fast motion of a mini surge at a time and locat ion on the upper glacier known from oth er meas ure ments the mean water velocity in the hydraulic system over the int erven ing distance is thereby determined 0 3 m s i the mean water velocity together with the water discharge 16 m3 s 1 at the terminus places con straints on the distribution of water velocity u and total cros s sectional area at of the flow paths along the gl acier base this leads to the con clusion that within the zone of mini surge occurrence in its unpe rturbed state u is about 0 1 m s 1 or possibly less at is about 10 2 m2 or possibly more and it must be divided into a very large number of small passag eways be blocked by constrict ions or both the total water cro ss se ction corresponds to a layer 0 1 2 m thick when spr ead unifo rmly over the glacier width the water velocity is clos e to or less than the propa gation velo city of the mini s urges bet ween the zone affected by mini surges and the stream a dyna mically less active lower section of the glacier is proba bly underlain by a small number of conduits in which the water velocity may be very high 2 m s i water di scharge follo wing the mini surges puts an upper limit on water storage changes ass ociated with the anomalous ice motion

rock type control on erosion induced uplift eastern swiss alps abstract there is growing evidence that quaternary rock uplift in parts of the european alps is a consequence of climate and erosion driven isostatic rebound contemporary rates of rock uplift u in the swiss alps show two distinctive dome like peak regions that attain 1 6 mm yr 1 we focus on the alpenrhein catchment and its surroundings where one of these peak regions spatially coincides with widely exposed cretaceous bundner schist and lower tertiary flysch field assessments and analyses of hillslope gradient distributions quantitatively demonstrate the low rock mass strength and high erodibility of these rocks this is reflected in mean postglacial catchment erosion rates d 4 mm yr 1 as opposed to 0 7 mm yr 1 in more resistant crystalline rocks though largely inferred from landslide and debris flow prone tributary catchments 2 the localised erosion rates in bundner schist and flysch are among the highest documented for the alps and corroborated by historic suspended sediment yields and thus export from the region we further find that the steepness of bedrock rivers the density of large landslides and d correlate with the highest values of u our observations highlight the possibility that erosion of mechanically weak bundner schist and flysch enhanced by large landslides may have contributed to regional crustal unloading and concomitant rock uplift irrespective of whether this is betraying a coupling between long term uplift and erosion modulated by rock type our findings indicate that long term 10 3 to 10 4 yr geomorphic signals contained in bedrock river steepness spatial density of large landslides and postglacial erosion rates strikingly correlate with regional gradients of historic 10 1 yr rock uplift rates

effect of slope failures on river network pattern a river piracy case study from the flysch belt of the outer western carpathians abstract landslides are important geomorphic agents in various mountainous settings we document here a case of river piracy from the upper part of the mala brodska valley in the vsetinske mts czech republic raca unit of the flysch magura group of nappes flysch belt of the outer western carpathians controlled by mass movement processes based on the field geological geomorphological and geophysical data we found out that the landslide accumulations pushed the more active river of out of two subparallel river channels with different erosion activity westwards and forced intensive lateral erosion towards the recently abandoned valley apart from the landslide processes the presence of the n striking fault accentuated by higher flow rates of the eastern channel as a result of its larger catchment area were the most critical factors of the river piracy as a consequence of the river piracy intensive retrograde erosion in the elbow of capture and also within the upper portion of the western catchment occurred deposits of two landslide dams document recent minimum erosion rates to be 18 8 mm ky 1 in the western captured catchment and 3 6 mm ky 1 in the eastern catchment respectively the maximum age of the river piracy is estimated to be of the late glacial and or the early holocene

a spatial database for landslides in northern bavaria a methodological approach landslide databases provide essential information for hazard modeling damages on buildings and infrastructure mitigation and research needs this study presents the development of a landslide database system named wisl wurzburg information system on landslides currently storing detailed landslide data for northern bavaria germany in order to enable scientific queries as well as comparisons with other regional landslide inventories wisl is based on free open source software solutions postgresql postgis assuring good correspondence of the various softwares and to enable further extensions with specific adaptions of self developed software apart from that wisl was designed to be particularly compatible for easy communication with other databases as a central pre requisite for standardized homogeneous data acquisition in the field a customized data sheet for landslide description was compiled this sheet also serves as an input mask for all data registration procedures in wisl a variety of in database solutions for landslide analysis provides the necessary scalability for the database enabling operations at the local server in its current state wisl already enables extensive analysis and queries this paper presents an example analysis of landslides in oxfordian limestones in the northeastern franconian alb northern bavaria the results reveal widely differing landslides in terms of geometry and size further queries related to landslide activity classifies the majority of the landslides as currently inactive however they clearly possess a certain potential for remobilization along with some active mass movements a significant percentage of landslides potentially endangers residential areas or infrastructure the main aspect of future enhancements of the wisl database is related to data extensions in order to increase research possibilities as well as to transfer the system to other regions and countries

artificial neural networks applied to landslide susceptibility assessment abstract landslide hazard mapping is often performed through the identification and analysis of hillslope instability factors usually managed as thematic data within geographic information systems gis in heuristic approaches these factors are rated by the attribution of scores based on the assumed role played by each of them in controlling the development of a sliding process other more refined methods based on the principle that the present and the past are keys to the future have also been developed thus allowing less subjective analyses in which landslide susceptibility is assessed by statistical relationships between past landslide events and hillslope instability factors the objective of this research is to define a method with the ability to forecast landslide susceptibility through the application of artificial neural networks anns the riomaggiore catchment a subwatershed of the reno river basin located in the northern apennines italy was chosen as an ideal test site as it is representative of many of the geomorphological settings within this region in the present application two different anns used in classification problems were set up and applied one belonging to the category of multi layered perceptron mlp and the other to the probabilistic neural network pnn family the hillslope factors that have been taken into account in the analysis were the following a lithology b slope angle c profile curvature d land cover and e upslope contributing area these factors have been classified on nominal scales and their intersection allowed 3342 homogeneous domains unique condition unit ucu to be singled out which correspond to the terrain units utilized in this analysis the model vector used to train the anns is a subset of that derived from the production of unique condition units and consists of 3342 records organized in input and output variable vectors in particular the hillslope factors once classified on nominal scales as binary numbers represent the 19 input variables while the presence absence of a landslide in a given terrain unit is assumed to be the output variable the comparison between the most up to date landslide inventory of the riomaggiore catchment and the hazardous areas as predicted by the anns showed satisfactory results with a slight preference for the mlp for this reason this is an encouraging preliminary approach towards a systematic introduction of ann based statistical methods in landslide hazard assessment and mapping

cellular automata as analysis and synthesis engines at the geomorphology ecology interface abstract the linkages between ecology and geomorphology can be difficult to identify because of physical complexity and the limitations of the current theoretical representations in these two fields of study deep divisions between these disciplines are manifest in the methods used to simulate process such as rigidly physical deterministic methods for many aspects of geomorphology compared with purely stochastic simulations in many models of change in landcover practical and theoretical research into ecology geomorphology linkages cannot wait for a single simulation schema which may never come as a result studies of these linkages often appear disjointed and inconsistent the grid based simulation framework for cellular automata ca allows simultaneous use of competing schemas ca use in general geographic studies has been primarily limited to urban simulations models of change for land cover both highly stochastic and or expert rule based in the last decade however methods for describing physically deterministic systems in the ca framework have become much more accurate the possibility now exists to merge separate ca simulations of different environmental systems into unified multiautomata models because cas allow transition rules that are deterministic probabilistic or expert rule based they can immediately incorporate the existing knowledge rules in ecology and geomorphology the explicitly spatial nature of ca provides a map like framework that should allow a simple and deeply rooted connection with the mapping traditions of the geosciences and ecological sciences

the surges of variegated glacier alaska u s a and their connection to climate and mass balance one of the questions still unanswered concerning the surge behavior of glaciers concerns their quasi periodic occurrence some results on the phenomenological connection between local cumulative balance and surge initiation of variegated glacier alaska u s a are discussed here based on climate data from neighboring weather stations an empirical relation between precipitation temperature and local mass balance is established and used to reconstruct the annual balance at a location in the accumulation area back to 1905 between the last four surges in 1946 47 1964 65 1982 83 and 1994 95 the ice equivalent cumulative balance was 43 5 m on average with a 1 error of 1 2 m although the existence of a surge level cannot be directly interpreted in physical terms it explains the variable length of the quiescent periods of variegated glacier by variations in the accumulation rate prior to the surge we use the surge level to hindcast former unobserved surges to compare the results with other surge datings obtained from photographs and to establish a complete surge history for variegated glacier for the 20th century

variegated glacier alaska usa a century of surges a 1995 surge of variegated glacier alaska usa is discussed in the context of its six 20th century predecessors especially the previous surge in 1982 83 which was studied in detail the average time between surge initiations is 15 years the 1995 surge was considerably weaker than its predecessors having a single phase or at most a very weak second phase the 1995 surge confirms that there is a seasonal cycle with surge initiation in winter and termination in the first part of the melt season and a correlation between weather and both surge termination date and surge extent two days of record high temperature correlated with the termination of the 1995 surge the most obvious issue is the absence of a strong second surge phase as there was in the 1982 83 surge culminating in a surge extent more in line with that of the predecessors this is considered in the light of a simple criterion for surge initiation and re initiation which depends upon the evolving basal shear stress

logistic regression model for predicting the failure probability of a landslide dam landslides may obstruct river flow and result in landslide dams they occur in many regions of the world the formation and disappearance of natural lakes involve a complex earth surface process according to the lessons learned from many historical cases landslide dams usually break down rapidly soon after the formation of the lake regarding hazard mitigation prompt evaluation of the stability of the landslide dam is crucial based on a japanese dataset this study utilized the logistic regression method and the jack knife technique to identify the important geomorphic variables including peak flow or catchment area dam height width and length in sequence affecting the stability of landslide dams the resulting high overall prediction power demonstrates the robustness of the proposed logistic regression models accordingly the failure probability of a landslide dam can also be evaluated based on this approach ten landslide dams formed after the 1999 chi chi earthquake the 2008 wenchuan earthquake and 2009 typhoon morakot with complete dam geometry records were adopted as examples of evaluating the failure probability the stable tsao ling landslide dam which was induced by the chi chi earthquake has a failure probability of 27 68 using a model incorporating the catchment area and dam geometry on the contrary the tangjiashan landslide dam which was artificially breached soon after its formation during the wenchuan earthquake has a failure probability as high as 99 54 typhoon morakot induced the siaolin landslide dam which was breached within one hour after its formation and has a failure probability of 71 09 notably the failure probability of the earthquake induced cases is reduced if the catchment area in the prediction model is replaced by the peak flow of the dammed stream for these cases in contrast the predicted failure probability of the heavy rainfall induced case increases if the high flow rate of the dammed stream is incorporated into the prediction model consequently it is suggested that the prediction model using the peak flow as causative factor should be used to evaluate the stability of a landslide dam if the peak flow is available together with an estimation of the impact of an outburst flood from a landslide dammed lake the failure probability of the landslide dam predicted by the proposed logistic regression model could be useful for evaluating the related risk

flotation and free surface flow in a model for subglacial drainage part 2 channel flow we present a new model of subglacial drainage incorporating flow in a network of channels and a porous sheet with water exchange between the two determined by pressure gradients the sheet represents the average effect of many linked cavities whilst the channels emerge from individual cavities that enlarge due to dissipationinduced melting the model distinguishes cases when the water pressure drops to zero in which case it allows for the drainage space to be only partially filled with water free surface flow and when the pressure reaches the ice overburden pressure in which case it allows for uplift of the ice to whatever extent is needed to accommodate the water flotation numerical solutions are found for a one dimensional flow line version of the model the results capture typically observed or inferred features of subglacial drainage systems including open channel flow at the ice margin seasonal channel evolution and high water pressures and uplift of the ice surface driven by rapid changes in water supply

large landslides and deep seated gravitational slope deformations in the czech flysch carpathians new lidar based inventory abstract moderate relief landscapes such as the czech flysch outer western carpathians cowc in comparison with alpine regions are rarely subject to extensive landslide inventory mapping an understanding of landslides in such a landscape is needed because densely populated hilly landscapes in temperate zones are usually of major socio economic importance in this study we performed the first lidar based landslide mapping for the entire cowc area 7539 km2 one of the most landslide prone regions in europe by calculating various landscape and landslide metrics we infer the distribution frequency area relationships kinematics and controls of mass movements with special attention on large landslides 0 1 km2 and deep seated gravitational slope deformations dsgsds we mapped a total of 13 611 landslides of which 1357 failures are large landslides and dsgsds whereas the lower and more subdued areas in the southern part of cowc are hotspots in terms of the total number of landslides the higher and more topographically pronounced areas in the northeast are affected predominantly by large landslides and dsgsds however landslides with 0 1 km2 are widespread throughout the whole territory of cowc a discrepancy also exists in the spatial distribution of different types of landslides rock slides and dsgsds are dominant in the north east while flow type landslides are dominant in the southern lower topographic relief with claystone dominated flysch we conclude that 1 distinct geological units nappes produce landslide populations with different frequency area distributions 2 stratigraphic composition alongside the tectonic style of flysch formations control the type of landslides 3 dsgsds affect mainly slopes formed by rigid rocks sitting atop soft formations and 4 geological conditions rather than topography control distribution of large landslides and dsgsds in cowc

flotation and free surface flow in a model for subglacial drainage part 1 distributed drainage we present a continuum model for melt water drainage through a spatially distributed system of connected subglacial cavities and consider in this context the complications introduced when effective pressure or water pressure drops to zero instead of unphysically allowing water pressure to become negative we model the formation of a partially vapour or air filled space between ice and bed likewise instead of allowing sustained negative effective pressures we allow ice to separate from the bed at zero effective pressure the resulting model is a free boundary problem in which an elliptic obstacle problem determines hydraulic potential and therefore also determines regions of zero effective pressure and zero water pressure this is coupled with a transport problem for stored water and the coupled system bears some similarities with hele shaw and squeeze film models we present a numerical method for computing time dependent solutions and find close agreement with semi analytical travelling wave and steady state solutions as may be expected we find that ice bed separation is favoured by high fluxes and low ice surface slopes and low bed slopes while partially filled cavities are favoured by low fluxes and high slopes at the boundaries of regions with zero water or effective pressure discontinuities in water level are frequently present either in the form of propagating shocks or as stationary hydraulic jumps accompanied by discontinuities in potential gradient

evolution of a landslide creating a temporary lake successful prediction the anzola landslide is a complex landslide that failed on the left side of the ceno valley northern apennines italy it was studied using a multidisciplinary approach in which geomorphology geology and engineering geology were combined to understand the kinematics evolution the main rock mass characteristics the behavior of the landslide and its morphologic evolution the anzola landslide in 1996 was probably a neo activation it was affected by at least three re activations recently always in connection with heavy rainfall which twice caused the blockage of the valley and formed a small lake the possibility of river blockage as a consequence of the re activation of the landslide was investigated using a grass gis based shell script that simulates the landslide material descent and computes the dam and lake sizes the simulations allowed assessment of the amount of the depleted material coupled with the morphological situation characterized by a very narrow riverbed that can lead easily to the formation of consistent damming and lakes this situation of course can represent a serious risk in case of a dam break and the ensuing flooding could affect downstream infrastructures and small villages

geomorphology and geochronology of sackung features uphill facing scarps in the central spanish pyrenees abstract the paper analyses uphill facing scarps and associated troughs developed in the oversteepened slopes of two neighbouring glacial valleys in the central spanish pyrenees previous studies of sackung landforms in the pyrenees have argued for deglacial unloading as the genetic mechanism but this causal and temporal relationship has not been proved due to the lack of chronological data the antislope scarps in the two studied locations vallibierna and estos are developed in palaeozoic metasedimentary rocks parallel to the contour lines and the structural grain occur in the intermediate sector of the hillslope and are up to 0 5 km long and several meters high a trench was excavated in a sackung trough fill in each of the valleys in order to gain information about their chronology and genesis charcoal from the lowermost unit in vallibierna provided an age of 5 9 cal ka for the sackung and extrapolation of the three dates obtained in estos indicates that the trough formed ca 7 6 7 8 cal ka deglaciation of the studied sectors of the valleys occurred between 16 and 13 ka the time lag of 5 ka suggests that glacial erosion and the subsequent debutressing of the oversteepened valley walls created slopes predisposed to sackung development but did not initiate the movement seismic shaking is proposed as a probable triggering factor this hypothesis although supported by the sudden deformation event recorded by a failure plane exposed in vallibierna trench and by the seismic and neotectonic activity of the area cannot be proved due to the lack of chronological information about paleoearthquakes

deep seated gravitational slope deformations in the highest parts of the czech flysch carpathians evolutionary model based on kinematic analysis electrical imaging and trenching deep seated gravitational slope deformations dsgsds played an important role during the quaternary evolution of mountain ridges formed by anisotropic flysch rocks of the outer western carpathians owc four dsgsd affected ridges in the highest part of the czech sector of the owc have been subjected to multidisciplinary investigation involving mapping structural and kinematic analysis geoelectrical imaging trenching and dating all the studied dsgsds are strongly predisposed by regional structural fabric given by the intersection of bedding planes joint sets and faults performed research suggests high diversity of mechanisms leading to the origin of individual dsgsds the area of a single dsgsd can be affected by various types of movements such as sackung lateral spreading toppling or incipient sliding electrical imaging and trenching revealed that besides these mechanisms anisotropic flysch massifs formed by thick bedded sandstones are strongly exposed to subsurface opening of air filled voids related to widened crevices such a process is driven by deep seated creep and translational sliding of sandstone beds upon plastic claystones whose strength has been reduced to residual values of the angle of internal friction performed radiocarbon and osl dating revealed that some of the studied dsgsds originated in the holocene period particularly in the atlantic and subboreal chronozones

geomorphic hazard assessment of landslide dams in south westland new zealand fundamental problems and approaches abstract quantitative assessments of landslide hazard usually employ empirical heuristic deterministic or statistical methods to derive estimates of magnitude frequency distributions of landsliding the formation and failure of landslide dams are common geomorphic processes in mountain regions throughout the world causing a series of consequential off site hazards such as catastrophic outburst floods debris flows backwater ponding up and downstream aggradation and channel instability conceptual and methodological problems of quantifying geomorphic hazard from landslide dams result from a aspects of defining landslide dam magnitude b scaling effects i e the geomorphic long range and long term implications of river blockage and c paucity of empirical data geomorphic hazard from a landslide dam break flood on the basis of conditional probabilities is being analysed for the alpine south westland region of new zealand where formation and failure of landslide dams is frequent quantification of the annual probability of landsliding and subsequent dam formation in the area is limited by historical and only partially representative empirical data on slope instability since landslide dam stability is a major control governing the potential of catastrophic outburst flooding the ensuing hazard is best assessed on a recurring basis gis based modelling of virtual landslide dams is a simple and cost effective approach to approximate site specific landslide dam and lake dimensions reservoir infill times and scaled magnitude of potential outburst floods although crude these order of magnitude results provide information critical to natural hazard planning mitigation or emergency management decisions

contribution of dendrochronology to the determination of magnitude frequency relationships for landslides abstract the determination of magnitude frequency m f relationships is necessary for landslide hazard assessment ideally this is achieved by using inventories of past landslide events recorded by technical units or aerial photo interpretation however direct sources of landslide data are often unavailable dendrogeomorphological techniques allow us to determine the frequency of events but few attempts have been made to estimate landslide magnitude by analysing the spatial distribution of disturbed trees this paper addresses m f determination for rockfalls debris flows and complex slides obtained by dendrogeomorphology the cases presented require the appropriate understanding of both the geomorphological context and the disturbance caused by landslide motion on trees both small and large rockfalls can be identified and dated by reconstructing the trajectories in the forest stand the larger the rockfall size the longer the path the higher the number of affected trees and the greater the area of deposition of rock fragments the area of damaged trees is proposed as an indicator of the rockfall magnitude the frequency and extent of a series of debris flows were reconstructed by mapping their deposits using relative dating criteria and by dating damaged trees local and global mudslide reactivations were deduced by sampling various tree generations and by analysing the location of the disturbed trees in the landslide units magnitude cumulative frequency curves were determined for the three cases

how do glaciers surge a review the quasi periodic oscillations between normal and fast motion exhibited by surge type glaciers provide the best observational opportunity to determine limiting conditions that allow fast motion the measurements from variegated glacier prove that its surge motion is caused by rapid sliding induced by high water pressure this arises from a major restructuring of the basal hydraulic system which impedes water discharge prior to and during surge although the evolving glacier geometry and stress distribution play a principal enabling role the seasonal timing of two distinct surge pulses each initiated in winter and terminated in summer indicates a major influence from variable external water inputs this influence is not considered in existing surge models and should promote caution in the use of data from temperate and subpolar surge type glaciers to deduce surge potential in polar ice masses the spatial spreading of surge motion from a zone of local initiation occurs by stress redistribution which may spread the surging zone rapidly upglacier or downglacier inside a region of active ice and by mass redistribution with compressional thickening at the surge front which enables down glacier propagation into less active ice the data from other surge type glaciers including the extensive data from medvezhiy glacier are not inconsistent with the above processes but are inadequate to establish whether completely different mechanisms operate in some surges the way by which water accumulates and produces fast sliding is not established in detail for any surge type glacier and may be different on different glaciers depending for example on the presence or absence of unconsolidated debris between the ice and rock

evolution of variegated glacier alaska u s a prior to its surge on presente l evolution saison apres saison des changements dans la geometrie et la vitesse du glacier et on tente de rattacher ces variations a la deformation de la glace et au glissement basal

large rockslides in the southern central andes of chile 32 34 5 s tectonic control and significance for quaternary landscape evolution abstract the distribution and age of large 0 1 km2 pliocene to recent rockslides in the chilean cordillera principal 32 34 5 s the southern central andes has been analyzed to determine the rockslide triggering mechanisms and impact on regional landscape evolution most of the rockslides appear in the western cordillera principal and cluster along major geological structures variographic analyses show spatial correlation between rockslides geological structures and shallow seismicity a relative chronosequence was calibrated with existing 14c and 40ar 39ar dates and new cosmogenic nuclide exposure ages for selected rockslides rockslide induced sediment yield was estimated with empirical relations for rockslide area distributions throughout the quaternary rockslides have delivered sediment to streams at rates equivalent to denudation rates of 0 10 0 06 mm a 1 while estimates using short term 20 a seismicity records are 0 3 0 2 0 6 mm a 1 the estimates of sediment transfer and the spatial distribution of rockslides reflect a landscape in which tectonic and geological controls on denudation are more significant than climate

landslide inventory maps new tools for an old problem landslides are present in all continents and play an important role in the evolution of landscapes they also represent a serious hazard in many areas of the world despite their importance we estimate that landslide maps cover less than 1 of the slopes in the landmasses and systematic information on the type abundance and distribution of landslides is lacking preparing landslide maps is important to document the extent of landslide phenomena in a region to investigate the distribution types pattern recurrence and statistics of slope failures to determine landslide susceptibility hazard vulnerability and risk and to study the evolution of landscapes dominated by mass wasting processes conventional methods for the production of landslide maps rely chiefly on the visual interpretation of stereoscopic aerial photography aided by field surveys these methods are time consuming and resource intensive new and emerging techniques based on satellite airborne and terrestrial remote sensing technologies promise to facilitate the production of landslide maps reducing the time and resources required for their compilation and systematic update in this work we first outline the principles for landslide mapping and we review the conventional methods for the preparation of landslide maps including geomorphological event seasonal and multi temporal inventories next we examine recent and new technologies for landslide mapping considering i the exploitation of very high resolution digital elevation models to analyze surface morphology ii the visual interpretation and semi automatic analysis of different types of satellite images including panchromatic multispectral and synthetic aperture radar images and iii tools that facilitate landslide field mapping next we discuss the advantages and the limitations of the new remote sensing data and technology for the production of geomorphological event seasonal and multi temporal inventory maps we conclude by arguing that the new tools will help to improve the quality of landslide maps with positive effects on all derivative products and analyses including erosion studies and landscape modeling susceptibility and hazard assessments and risk evaluations

tien shan geohazards database landslide susceptibility analysis abstract this paper is the second part of a new geohazards analysis applied to a large part of the tien shan central asia focused on landslide susceptibility computations that are based on recently compiled geographic geological and geomorphological data the core data are a digital elevation model an updated earthquake catalogue an active fault map as well as a new landslide inventory the most recently added digital data are a new simplified geological map an annual precipitation map as well as river and road network maps that were produced for the kyrgyz and tajik parts of the tien shan on the basis of these records we determine landslide densities with respect to morphological m geological g river distance r precipitation p earthquake e and fault f distance factors correlations were also established between scarp locations and the slope angle distance to rivers curvature these correlations show that scarps tend to be located on steeper slopes farther from rivers and on more convex terrain than the entire landslides on the basis of the landslide density values computed for each class of the aforementioned factors two landslide susceptibility maps are created according to the landslide factor analysis the first one considers correlations between the landslide occurrences and the first four factors mgrp the second one is based on the first map mgrp combined with the seismo tectonic influence e f on landslide distributions from the comparison of these two maps with actual landslide distributions we infer that the distances to rivers as well as to faults and past earthquakes most strongly constrain the susceptibility of slopes to landslides we highlight several zones where the landslide susceptibilities computed for the mgrp e f factors fit better the observed concentration of landslides than those computed for the mgrp factors alone for a few zones both maps produce high landslide susceptibilities that do not well reflect the observed low sub regional landslide activity for some cases we consider that some influencing factors must not have been well taken into consideration for others we show that we simply had missed landslide detections at the scale of the mountain range the computed landslide susceptibility maps fit the observed landslide distributions relatively well but these maps only represent the spatial component of landslide hazards temporal aspects are not considered by this analysis

deep structures of slopes connected with sandstone crags in the upland area of the świetokrzyskie holy cross mountains central poland abstract deep seated gravitational deformations of slopes are commonly observed and described in mountains but faintly manifested and thus neglected in upland areas thanks to the geophysical methods e g ert as well as detailed surface surveys and studies in caves such deformations have been discovered and described in the region of the wietokrzyskie holy cross mountains central poland which is an upland area of usually gentle slopes of a height of several tens of metres the deformations which have been studied on 20 30 m high slopes formed of sandstone series alternating with claystone siltstone and heterolithe series represent various movements from slight rotational and translational ca 1 m movements through horizontal and vertical shifts of several metres to significant dislocations of sandstone corestones embedded within the regolith forming the slopes the last mentioned structures are currently relics completely masked by subsequent slope processes and their origin should be related to specific periglacial and even sub glacial conditions of the pleistocene on the other hand as confirmed by radiocarbon dating and other mapping slight movements of relatively low slopes can even be active nowadays these deformations that occur in regions of a relatively low relief and have so far been neglected or considered to be unique are possibly even more frequent and should be studied using modern geophysical and other methods

complex landslide terrain in the kamienne mountains middle sudetes sw poland dense forest hides a complex landslide terrain in the kamienne mountains a part of the sudetes range in central europe combined geomorphological geophysical and dendrochronological research was carried out in three representative localities in order to decipher patterns of landslide evolution to determine the extent of slope deformations and to assess the contemporary activity of landslide terrain field mapping revealed the very complex nature of slope failures both in space and time deep seated sliding was the principal type of movement and was followed by rock wall retreat by fall in the depletion zone and earthflows in the toe area electric resistivity survey proved useful in constraining geometry of landslide units and suggests an occurrence of underground voids in the lesista landslide area dendrochronological research focused on tree ring reduction reaction wood wound and scar analysis that helped to unravel the pattern of debris supply and movement subsequent to the main events which includes free fall talus creep and sliding over snow cover today landslide complexes are at different stages of evolution whereas in some places the activity has been largely completed in others we have found the evidence for failure surfaces ready to accommodate movement hence although some landslides may be relict it is unjustified to extend this notion to all signs of hillslope instability in the area

regional mapping and characterisation of old landslides in hilly regions using lidar based imagery in southern flanders abstract analysis of lidar derived imagery led to the discovery of more than 330 pre holocene to recent landslides in southern flanders 4850 km 2 the morphology of three landslides including the 266 5 ha deep seated gravitational slope deformation in alden biesen was investigated in more detail the analysis of the morphological and topographical characteristics width length relation frequency area distribution and topographical threshold of the landslides revealed important differences compared to the characteristics reported in other landslide studies and helped understanding possible landslide triggering mechanisms especially the possibility of a seismic origin of the landslides was investigated finally a heuristic model for region wide landslide susceptibility mapping was successfully tested the susceptibility model and map allow prediction of future landslide locations and contribute to better understanding the role of individual causal factors on landslide location and spatial density the results suggest that landslides on low gradient soil mantled hills are a more important contributor to landscape evolution of hilly areas than was hitherto thought the morphology of all hilly regions of flanders is clearly marked by landslide processes and higher landslide densities often coincide with the presence of quaternary active faults this study further shows that high resolution topographical data such as lidar significantly contributes to a better detection of old previously unknown landslides

how much do we really know about glacier surging some of the ideas about glacier surging are considered mainly but not entirely in the light of observations of temperate glaciers in alaska u s a made within the last 15 years climate has an influence on surge recurrence interval climate and weather also affect surge initiation termination and magnitude regional studies lead to the speculation that subglacial till plays a key role in surging and it has been found under all surge type glaciers studied so far including black rapids and variegated glaciers alaska in most of the glaciers studied till deformation processes dominate the motion in quiescence the linked cavity model of surge triggering and rapid motion is not consistent with these observations but the limited coverage of the observations does not rule it out under parts of the glaciers studied the till observations in alaska raise old questions about the interaction between till and the hydraulic systems of temperate glaciers the role of stored water which observations show to be active even in winter on black rapids glacier is noted

applying genetic algorithms for calibrating a hexagonal cellular automata model for the simulation of debris flows characterised by strong inertial effects abstract in modelling complex a centric phenomena which evolve through local interactions within a discrete time space cellular automata ca represent a valid alternative to standard solution methods based on differential equations flow type phenomena such as lava flows pyroclastic flows earth flows and debris flows can be viewed as a centric dynamical systems and they can therefore be properly investigated in ca terms sciddica s4a is the last release of a two dimensional hexagonal ca model for simulating debris flows characterised by strong inertial effects s4a has been obtained by progressively enriching an initial simplified model originally derived for simulating very simple cases of slow moving flow type landslides using an empirical strategy in s4a the inertial character of the flowing mass is translated into ca terms by means of local rules in particular in the transition function of the model the distribution of landslide debris among the cells is obtained through a double cycle of computation in the first phase the inertial character of the landslide debris is taken into account by considering indicators of momentum in the second phase any remaining debris in the central cell is distributed among the adjacent cells according to the principle of maximum possible equilibrium the complexities of the model and of the phenomena to be simulated suggested the need for an automated technique of evaluation for the determination of the best set of global parameters accordingly the model is calibrated using a genetic algorithm and by considering the may 1998 curti sarno southern italy debris flow the boundaries of the area affected by the debris flow are simulated well with the model errors computed by comparing the simulations with the mapped areal extent of the actual landslide are smaller than those previously obtained without genetic algorithms as the experiments have been realised in a sequential computing environment they could be improved by adopting a parallel environment which allows the performance of a great number of tests in reasonable times

giant non catastrophic landslides and the long term exhumation of the european alps landslides influence local slope morphology affect sediment flux from hillslopes to rivers and mass wasting in response to tectonics and climate forcing however the links between giant non catastrophic landslides known as deep seated gravitational slope deformations dsgsds and the long term evolution of orogenic landscapes are almost unknown we explore these links in the european alps using the first orogen scale inventory of dsgsds 900 over an area 105 km2 and a dataset of published apatite fission track ages 1000 that provides an estimate of the long term exhumation patterns of the orogen we show that dsgsds are more widespread than previously considered and exhibit an orogen scale distribution not explained by well known local lithological and structural controls we test the hypothesis that this orogen scale distribution correlates to the long term evolution of the alps by subdividing the study area into 37 square sub areas 50 50 km classified according to combinations of long term exhumation and mean annual rainfall on each sub area we perform a morphometric analysis of topography hypsometry relief slope excluding local and regional controls due to rock type and structure dsgsds tend to cluster in areas with intermediate exhumation rates fission track age between 10 and 40 ma where large scale topography is less dissected and incision is localised along major valleys here dsgsd abundance correlates positively with the degree of valley incision and related relief instead dsgsds lack in areas which underwent either low exhumation rates resulting in insufficient relief production or high exhumation rates associated to rapid uplift or higher erosional dissection of topography negative correlation between dsgsd abundance and mean annual rainfall suggests that effective hydrological surface processes contribute on the long term timescale to the development of large scale topography unfavourable to dsgsds especially in areas of high exhumation rates where dsgsds are abundant long lasting slope deformations effectively adjust post glacial relief by reducing slope inclination values and are thus expected to significantly contribute to the long term denudation of active orogens

propagation of a glacier surge into stagnant ice the propagation of the surge of variegated glacier into its terminal lobe was observed by daily surveying of a longitudinal line of closely spaced markers extending up glacier from a stagnant zone of thin 40 m nearly motionless ice near the terminus across a front zone to a surge zone of thicker 100 m rapidly moving 20 m d 1 ice above within the front zone there were large angles of upward motion 30 compressive longitudinal strain rates 0 1 d 1 and upward vertical velocities 5 m d 1 within the surge zone the ice motion was nearly parallel to the ice surface and longitudinal gradients were small the deformation pattern produced microcracking exfoliation and buckling of surface ice longitudinal cracking longitudinal chasms and an increase in glacier volume the front zone propagated at an average speed of about 40 m d 1 or roughly twice the surge speed of the ice above the front this factor is determined by the thickness jump across the front finite element modeling constrained by measured geometry and surface velocity was used to deduce the velocity and stress at depth the velocity in the surging zone occurs almost entirely by sliding the sliding rate drops abruptly beneath the center of the front zone to zero in the stagnant zone a comparison of basal velocity and shear stress distributions indicates a highly lubricated area beneath the upper part of the front zone and a locked area beneath the lower part of the front zone normal stress at the bed is not significantly different from overburden and there is no high compressive normal stress on the bed to act as a pressure dam to obstruct water flow through the front zone

are sackungen diagnostic features of de glaciated mountains abstract deep seated gravitational slope deformations dsgsds with characteristic sackung landforms e g double crests trenches uphill facing scarps and toe bulging are considered by some researchers to be diagnostic features indicating past mountain glaciations however an extensive literature review on sackung features throughout the world reveals that in some regions paraglacial processes are not the causes of such phenomena sackungen occur across a diverse spectrum of mountain types with different morphoclimatic histories including regions that have never experienced glaciation to reinforce that sackungen may originate independently of glaciation we also include two case studies from the western carpathians czech republic and slovakia which are supported by detailed geomorphic mapping trenching and absolute dating 10 be 14 c and osl on the ond ejnik ridge outer western carpathians czech republic sackungen occur in the mid holocene in the medium high mountains which are beyond the pleistocene glacial limits on the salatin mt tatra mts slovakia the sackungen which occur in formerly glaciated terrain date between 7 5 and 4 2 ka bp representing a 4 ka time lag after the disappearance of glaciers this suggests that the direct link between the ice retreat and the onset of sackung formation is not obvious even in the case of the once glaciated mountain range although paraglacial stress release is undoubtedly one of the crucial causes of sackung genesis in many mountain regions it is not the only important mechanism therefore despite occurring in numerous de glaciated mountains sackung features cannot be considered as proof of past mountain glaciations e g during analysis of extra terrestrial settings

deep seated gravitational slope deformations in the european alps abstract deep seated gravitational slope deformations dsgsd are widespread phenomena recognized in different mountain ranges worldwide the distribution of such phenomena at the scale of a mountain belt has rarely been systematically analysed in the past aim of the paper is to present and discuss an inventory map of dsgsd at the scale of the entire european alps in order to review existing knowledge and investigate general controls on these phenomena the criteria adopted for their classification and distinction are presented a total of 1033 dsgsds ranging in size between 0 03 and 108 km 2 have been mapped the inventory has been validated against available local or regional landslide inventories at different scales and prepared by different authors using different approaches the frequency area relationship for the mapped features is presented the spatial distribution of the mapped dsgsd has been quantified by discretizing the study area into regular square grids with different resolution and analysed with respect to a variety of geological geomorpohological and morphometric variables and of their clustering discriminant principal component and cluster analyses have been performed to define the most important controlling and predisposing factors results suggest that the occurrence of foliated metamorphic rocks lgm ice thickness local relief and related parameters slope size drainage density and river stream power are the local parameters most positively correlated to dsgsd occurrence the impact of these phenomena on slope morphology in terms of hypsometry and slope gradient adjustment is also discussed

simulation of the parma river blockage by the corniglio landslide northern italy abstract near the village of corniglio in the northern apennines about 40 km sw of parma a big landslide was recently 1994 1996 subjected to reactivation damaging many buildings and partially obstructing the parma river in this work we have carried out a quantitative analysis of the recent evolution of the landslide with the help of a geographic information system gis in order to predict the most plausible future developments then various simulations of landslide descent were carried out and above all to evaluate the possibility of blockage formation to this purpose two computer programs that simulate the material descent through a cellular automata model and define blockage characteristics were written many different simulations were carried out 16 of which are presented here for each of them the computer output consists of a table defining the quantity of displaced material area and volume of the dam and lake and of a map showing the areas involved in the landslide movement and upstream flooding in order to assess the probability of blockage formation and dam stability we applied the simulation results to some empirical rules defined by preceding authors through statistical analysis carried out on a high number of analogous phenomena these rules suggest that it is very unlikely that blockage takes place as the result of very slow landslide velocity riverbed width and high erodibility of the material if it were to occur the size and shape of the dam seem sufficient to guarantee a considerable degree of stability making a sudden failure improbable

complex rupture mechanism and topography control symmetry of mass wasting pattern 2010 haiti earthquake the 12 january 2010 mw 7 0 haiti earthquake occurred in a complex deformation zone at the boundary between the north american and caribbean plates combined geodetic geological and seismological data posited that surface deformation was driven by rupture on the leog ne blind thrust fault while part of the rupture occurred as deep lateral slip on the enriquillo plantain garden fault epgf the earthquake triggered 4490 landslides mainly shallow disrupted rock falls debris soil falls and slides and a few lateral spreads over an area of 2150 km2 the regional distribution of these slope failures defies those of most similar earthquake triggered landslide episodes reported previously most of the coseismic landslides did not proliferate in the hanging wall of the main rupture but clustered instead at the junction of the blind leog ne and epgf ruptures where topographic relief and hillslope steepness are above average also low relief areas subjected to high coseismic uplift were prone to lesser hanging wall slope instability than previous studies would suggest we argue that a combined effect of complex rupture dynamics and topography primarily control this previously rarely documented landslide pattern compared to recent thrust fault earthquakes of similar magnitudes elsewhere we conclude that lower static stress drop mean fault displacement and blind ruptures of the 2010 haiti earthquake resulted in fewer smaller and more symmetrically distributed landslides than previous studies would suggest our findings caution against overly relying on across the board models of slope stability response to seismic ground shaking

giant landslides topography and erosion abstract distributions of slope angles in tectonically active mountain belts point to the development of threshold conditions where hillslopes attain a critical inclination or height at which they fail readily because of limitations in material strength it has been proposed that hillslopes adjust to rapid uplift and bedrock incision through an increase in the rate of relief limiting landsliding rather than gradual slope steepening here we test this concept by investigating the relationship between mean local relief h which we take to be a proxy of long term erosion rates e and the occurrence of over 300 of the largest v 10 8 m 3 terrestrial landslides on earth we find that nearly two thirds of these giant landslides have occurred in the steepest 5 of the earth s land surface where relief is close to its proposed upper strength limit they are primarily located in deeply incised valleys along fault bounded fringes of active mountain belts and in volcanic arcs this distribution coincides with areas of high long term erosion rates 4 mm yr 1 confirming that giant landslides contribute to rapid denudation of mountains most of the eroded volume is concentrated in the smallest but steepest parts of mountain belts and volcanic arcs first order estimates of minimum erosion rates accomplished by the largest landslides are 0 01 mm yr 1 these rates are between 1 and 10 of the late pleistocene to holocene mean erosion rates in a given area importantly the landslide erosion rates show a nonlinear increase with mean local relief suggesting that the contribution of giant landslides in total and per event increases significantly with increasing overall erosion rates however giant landslides also occur in areas of lower than average relief h 300 700 m irrespective of whether threshold hillslopes have developed or not factors contributing to these failures include soft rocks extensive low angle discontinuities high rates of fluvial bedrock incision and tectonically driven deformation and slope loading

the origin of shallow landslides in moravia czech republic in the spring of 2006 abstract at the end of march 2006 the czech republic cz witnessed a fast thawing of an unusually thick snow cover in conjunction with massive rainfall most watercourses suffered floods and more than 90 shallow landslides occurred in the moravian region of eastern cz primarily in non forested areas this region geologically part of the outer western carpathians is prone to landslides because the bedrock is highly erodible mesozoic and tertiary flysch the available meteorological data depth of snow water equivalent of the snow cumulative rainfall air and soil temperatures from five local weather stations were used to construct indices quantitatively describing the snow thaw among these the total cumulative precipitation tcp combines the amount of water from both thawing snow and rainfall this concurrence of rain and runoff from snow melt was the decisive factor in triggering the landslides in the spring the tcp index was applied to data of snow thaw periods for the last 20 years when no landslides were recorded this was to establish the safe threshold of tcp without landslides the calculated safe threshold value for the region is ca 100 mm of water delivered to the soil during the spring thaw corresponding to ca 11 mm day 1 in 2006 10 of the landslides occurred under or at 100 mm of tcp the upper value of 155 mm covered all of the landslides

glacier surge mechanism 1982 1983 surge of variegated glacier alaska the hundredfold speedup in glacier motion in a surge of the kind the kind that took place in variegated glacier in 1982 1983 is caused by the buildup of high water pressure in the basal passageway system which is made possible by a fundamental and pervasive change in the geometry and water transport characteristics of this system the behavior of the glacier in surge has many remarkable features which can provide clues to a detailed theory of the surging process the surge mechanism is akin to a proposed mechanism of overthrust faulting

power law correlations of landslide areas in central italy abstract we have studied the frequency area statistics of landslides in central italy we consider two data sets data set a contains 16 809 landslide areas in the umbria marche area of central italy they represent a reconnaissance inventory of very old old and recent modern landslides the noncumulative frequency area distribution of these landslides correlates well with a power law relation exponent 2 5 over the range 0 03 km 2 a l 2 data set b contains 4233 landslides that were triggered by a sudden change in temperature on 1 january 1997 resulting in extensive melting of snow cover an inventory of these snow melt triggered landslides was obtained from aerial photographs taken 3 months after the event these landslides also correlate well with a power law relation with exponent 2 5 over the range 0 001 km 2 a l 2 we show that the correlation of data set b is essentially identical to the correlation of 11 000 landslides triggered by the 17 january 1994 northridge california earthquake we attribute a rollover for small landslides in data set a to incompleteness of the record due to erosion and other processes and to limitations in the reconnaissance mapping technique used to complete the inventory on the other hand we conclude that rollovers for small landslides in data set b and the california earthquake data are real and are associated with the surface morphology we conclude that the power law distribution is valid over a wide range of landslide areas and discuss possible reasons we also discuss the contribution of the snow melt and earthquake triggered landslide events to the total landslide inventory

use of lidar derived images for mapping old landslides under forest large deep seated landslides are common features in the flemish ardennes belgium as most of these old 100 years landslides are located under forest in this hilly region aerial photograph interpretation is not an appropriate landslide mapping method this study tested the potential of lidar light detection and ranging images for mapping old landslides under forest landslide inventory maps were created for a 125 km2 area by applying the expert knowledge of seven geomorphologists to lidar derived hillshade slope and contour line maps in a gis environment each of the seven lidar based landslide inventories was compared i with the other six ii with a detailed field survey based inventory and iii with a comparable study in which topographic data were extracted from a topographical map the combination of the percentage of field landslides indicated by an expert and the percentage of positional discrepancies expressed in terms of positional mismatch were used to evaluate the quality of the lidar based inventory maps high quality lidar derived landslide inventory maps contain more than 70 per cent of the landslides mapped during the field survey and have positional discrepancies smaller than 70 per cent when compared with the field survey based inventory map four experts and the combination map of all experts satisfied these criteria together the seven experts indicated all landslides mapped in the field importantly lidar enabled the experts to find ten new landslides and to correct the boundaries of eleven of the 77 landslides mapped during the field survey hence this study showed that large scale lidar derived maps analysed by experienced geomorphologists can significantly improve field survey based inventories of landslides with a subdued morphology in hilly regions copyright 2006 john wiley sons ltd

numerical modelling of the historic front variation and the future behaviour of the pasterze glacier austria an ice flow model is used to simulate the front variations of the pasterze glacier austria the model deals explicitly with the ice flux from sub streams and tributaries to the main ice stream the dynamic calibration method adopted successfully calibrates the ice flow model under a non steady state condition despite the complexity of the glacier geometry the ice dynamics of the pasterze are adequately simulated results of the sensitivity experiments suggest that the pasterze glacier has been in a non steady state most of the time and has a response time of 34 50 years projections of the behaviour of the pasterze in the next 100 years are made under various climate scenarios results suggest that the pasterze will undergo a substantial retreat if there is future warming the glacier is likely to retreat 2 5 km by the year 2100 the ice volume could be reduced by 24 63 by the end of the 21st century

the failure mechanism of a late glacial sturzstrom in the subalpine molasse leckner valley vorarlberg austria a number of prehistoric landslides and rock avalanches occurred in the folded and faulted section of the molasse zone in vorarlberg austria some developed into a sturzstrom defined as a rapidly moving fluidised mass movement of large volumes of rock derived from the disintegration of a falling rock mass that spread under the influence of gravity their impact on the landscape usually is related to obstruction of rivers and valleys in this paper we analyse the geomorphology and the failure mechanism of a relative small sturzstrom the failure mechanism can be described as a buckling failure the morphological situation indicates that failure took place after local deglaciation by the end of the upper wurm the period of failure coincides with glacial and ice marginal remnants which developed between 15 000 and 14 600 bp the lithological sequence and rock structure as well as the impact of the processes related to the former glacial environment were major causal conditions the rock sequence consists of conglomerates sandstone layers and marls next to glacial scouring which increased the inclination of the valley slopes the effect of late glacial unloading and postglacial processes such as weathering and fluvial erosion subsequently weakened the mass rock fabric until failure occurred discontinuity orientation measurements geostructural and geomechanical conditions and the former hydrological and geomorphological conditions support bucklings failure in fact three hinge buckling may have occurred the frontal section of the sturzstrom consists mainly of large conglomerate blocks averaging 1 5 m3 in volume although megablocks reaching of up to 4000 m3 are present as well the volume of the entire sturzstrom equals approximately 10 107 m3 present activity is only restricted to minor rock falls derived from the conglomerates and mudflows originating from the marl layers

controls on large landslide distribution and implications for the geomorphic evolution of the southern interior columbia river basin large landslides 0 1 km 2 are important agents of geomorphic change while most common in rugged mountain ranges large landslides can also be widespread in relatively low relief several 100 m terrain where their distribution has been relatively little studied a fuller understanding of the role of large landslides in landscape evolution requires addressing this gap since the distribution of large landslides may affect broad regions through interactions with channel processes and since the dominant controls on landslide distribution might be expected to vary with tectonic setting we documented 400 landslides between 0 1 and 40 km 2 across 140 000 km 2 of eastern oregon in the semiarid southern interior columbia river basin the mapped landslides cluster in a nw se trending band that is 50 100 km wide landslides predominantly occur where even modest local relief 100 m exists near key contacts between weak sedimentary or volcaniclastic rock and coherent cap rock fault density exerts no control on landslide distribution while 10 of mapped landslides cluster within 3 10 km of mapped fold axes landslide occurrence is curtailed to the ne by thick packages of coherent basalt and to the sw by limited local relief our results suggest that future mass movements will localize in areas stratigraphically preconditioned for landsliding by a geologic history of fluviolacustrine and volcaniclastic sedimentation and episodic capping by coherent lava flows in such areas episodic landsliding may persist for hundreds of thousands of years or more producing valley wall slopes of 7 13 and impacting local channels with an evolving array of mass movement styles

the 1982 83 surge and antecedent quiescent phase of variegated glacier revising the original dataset for application in flow line models