optimizing landslide susceptibility zonation effects of dem spatial resolution and slope unit delineation on logistic regression models abstract we perform landslide susceptibility zonation with slope units using three digital elevation models dems of varying spatial resolution of the ubaye valley south french alps in so doing we applied a recently developed algorithm automating slope unit delineation given a number of parameters in order to optimize simultaneously the partitioning of the terrain and the performance of a logistic regression susceptibility model the method allowed us to obtain optimal slope units for each available dem spatial resolution for each resolution we studied the susceptibility model performance by analyzing in detail the relevance of the conditioning variables the analysis is based on landslide morphology data considering either the whole landslide or only the source area outline as inputs the procedure allowed us to select the most useful information in terms of dem spatial resolution thematic variables and landslide inventory in order to obtain the most reliable slope unit based landslide susceptibility assessment

flow behaviour and runout modelling of a complex debris flow in a clay shale basin identification of debris flow hazard areas necessitates the knowledge of the flow thickness and the runout distance both have been investigated using a numerical runout model on the faucon stream south french alps representative of clay shale basins results of various rheological tests and numerical experiments are presented and discussed the calibration of the model was undertaken using the results of both geomorphological surveys and sedimentological analyses rheological tests using either a parallel plate rheometer a coaxial rheometer slump tests and an inclined plane were carried out on several samples results have shown that the flow behaviour could be described by an herschel bulkley constitutive equation the rheological responses of several natural suspensions collected from surficial deposits sandstones moraines weathered black marls were also investigated in order to model the runout of the flow the model bing was used the model describes well the influence of each type of sediment on the behaviour runout distance deposit thickness of the flow although the velocities were significantly overestimated different risk scenarios are tested and discussed copyright 2005 john wiley sons ltd

crystallization and welding variations in a widespread ignimbrite sheet the rattlesnake tuff eastern oregon usa the 7 05 ma rattlesnake tuff covers ca 9000 km2 but the reconstructed original coverage was between 30000 and 40000 km2 thicknesses are remarkably uniform ranging between 15 and 30 m for the most complete sections only 13 of the area is covered with tuff thicker than 30 m to a maximum of 70 m the present day estimated tuff volume is 130 km3 and the reconstructed magma volume of the outflow is 280 km3 dre dense rock equivalent the source area of the tuff is inferred to be in the western harney basin near the center of the tuff distribution based mainly on a radial exponential decrease in average pumice size and is consistent with a general radial decrease in welding and degree of post emplacement crystallization rheomorphic tuff is found to a radius of 40 60 km from the inferred source four facies of welding and four of post emplacement crystallization are distinguishable they are non welded incipiently welded partially welded and densely welded zones and vapor phase pervasively devitrified spherulite and lithophysae zones the vapor phase pervasively devitrified and lithophysae zones are divided into macroscopically distinguishable subzones at constant thickness 20 3 m and over a distance of 1 3 km nonrheomorphic sections can cary between two extremes a entirely vitric sections grading from nonwelded to incipiently welded and b highly zoned sections highly zoned sections have a basal non to densely welded vitric tuff overlain by a spherulite zone that grades upward through a lithophysae dominated zone to a zone of pervasive devitrification which in turn is overlain by a zone of vapor phase crystallization and is capped by partially welded vitric tuff a three dimensional welding and crystallization model has been developed based on integrating local and regional variations of 85 measured sections strong local variations are interpreted to be the result of threshold governed welding and crystallization controlled by residence time above a critical temperature which is achieved through differences in thickness and accumulation rate

landslides and climate change in the italian dolomites since the late glacial abstract the paper deals with the relationship between the temporal occurrence of landslides and climatic changes in the italian dolomites since the late glacial after an introduction on the state of the art with particular reference to the alpine region the results of recent investigations in the two study sites are illustrated at cortina d ampezzo several landslides were dated mainly by the radiocarbon method the most ancient landslide event there involved large rock slides which affected the dolomitic slopes following the withdrawal of glaciers after the last glacial maximum lgm and also slides and flows mainly occurring in pelitic materials of the valley floors from 13 000 to 10 000 cal bp a later series of flows occurred between 5500 and 2500 cal bp in the upper badia valley alta badia the most ancient events go back to 10 000 and 9000 cal bp and correspond with earth flows that followed vast rotational slides affecting the bedrock up to a depth of about 50 m more recent earth flows involving more modest amounts of material took place between 6500 and 2300 cal bp by analysing the dates from the two study areas it was possible to correlate the recorded increase of landslide activity with the climatic changes occurring at the boundary between the late glacial and the holocene and between the atlantic and the subboreal and to compare the results with those derived from other european regions the types and causes of landslides taking place in these two periods were substantially different reflecting the different morphoclimatic conditions that existed in the two areas when these mass movements were triggered finally notwithstanding the importance of non climatic causes such as geological structural factors and possible human influences it is concluded that many of the dated landslides can be considered as indicators of climatic change

processes spatio temporal factors and measurements of current erosion in the french southern alps a review present erosion in mountainous areas of western europe causes land management problems particularly for areas located downstream of erosion zones except for transalpine roads and ski resorts economic activities no longer require as much space as they did in the past therefore natural reforestation has provided signi cant protection for alpine hillslopes during the 20th century however extreme oods continue to cause severe damage in intra alpine valleys as well as in piedmont and surrounding plains making the study of present water erosion phenomena very important many studies have investigated the processes and factors of water erosion on slopes at both the catchment and plot scales they have focused on rock fragmentation and transportation in different elds the spatial and temporal explanatory variables the consequences downstream ooding sedimentation river bed evolution and the impact of oods in the french alps present erosion has been studied in a variety of outcrops with several recent studies conducted in elds such as marls clayey deposits molasses and moraines these kinds of outcrops are found throughout the alpine massif including an area of special interest on the great jurassic black marl outcrop where badlands are frequently observable geomorphologists and hydrologists have been particularly interested in the strong erosion processes in marls seeking to determine the main patterns and the impact of spatial and temporal factors on soil loss quantities the main climatic factors of rock disaggregation were found to be the freeze thaw and wet dry cycles which destroy rock cohesion and the splash effect of rain the principal site variables are vegetation cover exposure and dip slope angle erosion rates are two or three orders of magnitude higher on bare soils than on pastures northern aspect slopes suffer two to four times as much soil loss as southern aspect slopes finally the angle formed by the slope and the dip also determines different behaviours erosion rates are higher when slope and dip are perpendicular than when they are parallel the transportation agents are mostly debris ows and runoff caused by intense precipitation annual erosion depth in the marls is generally assumed to be substantial up to 10 mm the high value can be explained by the severity of the climatic conditions and the brittleness of the lithology which results in numerous fractures copyright 2003 john wiley sons ltd

groundwater surface waters interactions at slope and catchment scales implications for landsliding in clay rich slopes understanding water infiltration and transfer in soft clay shales slopes is an important scientific issue especially for landsliding geochemical investigations are carried out at the super sauze and draix laval landslides both developed in the callovo oxfordian black marls with the objective to define the origin of the groundwater in situ investigations soil leaching experiments and geochemical modeling are combined to identify the boundaries of the hydrological systems at super sauze the observations indicate that an external water flow occurs in the upper part of the landslide at the contact between the weathered black marls and the overlying formations or at the landslide basement through a fault network such external origin of water is not observed at the local scale of the draix laval landslide but is detected at the catchment scale with the influence of deep waters in the streamwater quality of low river flows hydrogeological conceptual models are proposed emphasizing the role of the interactions between local slope and regional catchment flow systems the observations suggest that this situation is a common case in the alpine area expected consequences of the regional flows on slope stability are discussed in term of rise of pore water pressures and physicochemical weathering of the clay shales

spatio temporal analysis of a complex landslide in the northern apennines italy by means of dendrochronology dendrochronology is used to determine the spatial and temporal development of movements in a complex landslide located in the northern apennines the analysis of trees growing on the landslide body enabled us to date their colonisation pattern which starts from the 1920s and increases mainly after 1950 since then sampled trees recorded with growth anomalies the movements involving the landslide body in 1956 1957 1982 1983 1990 1995 and 1998 these movements are reactivations of the main landslide that probably occurred in the last decades of the 19th century in 1980 trees on the upper landslide body were involved in a rock fall due to the expansion of the main scarp microsections cut out from selected tree ring sequences allowed seasonal dating of the highlighted movements which mostly occurred in early spring meteorological and seismic time series were analyzed in order to relate them with reactivations and to search for correlations and triggering events the seismic activity although characterized by low magnitudes could be able either to trigger the movements 1990 or to destabilize the ground where rainfalls could have been playing the first role in triggering the reactivation probably in 1982 1983 and 1995 the other reactivations seem to be linked either to long lasting rainfalls or to monthly rainfall peaks mostly following dry periods

ground based multi view photogrammetry for the monitoring of landslide deformation and erosion recent advances in multi view photogrammetry have resulted in a new class of algorithms and software tools for more automated surface reconstruction these new techniques have a great potential to provide topographic information for geoscience applications at significantly lower costs than classical topographic and laser scanning surveys based on open source libraries for multi view stereo photogrammetry and structure from motion this study investigates the accuracy that can be obtained from several processing pipelines for the 3d surface reconstruction of landslides and the detection of changes over time two different algorithms for point cloud comparison are tested and the accuracy of the resulting models is assessed against terrestrial and airborne lidar point clouds change detection over a period of more than two years allows a detailed assessment of the seasonal dynamics of the landslide the possibility to estimate sediment volumes and 3d displacement are illustrated for the most active parts of the landslide algorithm parameters and the image acquisition protocols are found to have important impacts on the quality of the results and are discussed in detail

the geochemistry of potassic lavas from vulsini central italy and implications for mantle enrichment processes beneath the roman region major and trace element and 143nd 144nd 0 51209 0 51216 and 87sr 86sr 0 70879 0 71105 isotope analyses are presented on a representative group of lavas from the vulsini district of the roman magmatic province three distinct series are identified the high k and low k series are similar to those described from other italian volcanoes while the third is represented by a group of relative ly undifferentiated leucite basanites which are thought to be near primary mantle melts major and trace element variations within the high k series are consistent with fractional crystallisation from a parental magma similar to the most magnesian leucitites crustal contamination resulted in an increase in 87sr 86sr with increasing fractionation but it was superimposed on magmas which had already inherited a range of incompatible element and isotope ratios from enrichment processes in the sub continental mantle these are reviewed using the available results from vulsini roccamonfina and ernici transition element abundances and ta yb ratios indicate that the pre enrichment mantle was similar to that of e type morb and that these elements were not mobilised by the enrichment process mixing calculations suggest that three components were involved in the enrichment process mantle comparable with the source of morb and two other components rich in trace elements one the low k component had high sr nd th ta and ba nb and no europium anomaly while the second had lower sr nd a negative europium anomaly and very high th ta it was also characterised by low nb ba and high rb ba ratios similar to those reported from phlogopite rich peridotite xenoliths the trace element enrichment processes are therefore thought to have occurred in the mantle wedge above a subduction zone with the trace element characteristics of the high k end member reflecting the subduction of sediments and the stabilisation of mantle phlogopite

nine years of spatial and temporal evolution of the la valette landslide observed by sar interferometry abstract the la valette landslide located in the ubaye valley southern french alps has been investigated using 15 differential interferograms realized from ers 1 and ers 2 satellite radar images acquired between 1991 and 1999 both in 3 day cycle and tandem phase displacement values of the landslide have been deduced from the synthetic apenture radan sar interferometric products interpretation and compared with ground laser measurements four domains characterized by different velocity fields have been detected three of them can be distinguished from aerial photographs and field analysis the slow velocity of a resistant bar located in the eastern side of the landslide has been detected on sar interferograms between 1991 and 1996 changes in the landslide limits have been observed both in the upper and in the lower part the changes have been caused by a retrogression of the main scarp and a down slope progression of the main body of the landslide respectively the average daily velocity of the landslide between 1991 and 1999 derived by interferometric analysis decreased from 1 to 0 4 cm day in agreement with ground based measurements a peak velocity of around 2 cm day was observed in 1996

climate change increases frequency of shallow spring landslides in the french alps in this contribution past process activity is reconstructed on seven landslide bodies of the riou bourdoux catchment southeastern french alps based on an unusually dense data set of 3036 tree ring series extracted from 759 conifers we provide evidence for 61 landslide reactivations since a d 1898 based on logistic regressions and threshold analyses of monthly rainfall data and temperature anomalies we determine that the combination of snow rich winters and positive temperature anomalies in spring enhanced snowmelt seems to have driven landslide reactivations in the past since the early 1990s however landslide reactivations clearly have been on the rise and thereby exhibit excessive and unprecedented rates of activity 12 5 events per 10 yr at the scale of the riou bourdoux catchment from the data evidence exists for a shift from snowmelt induced landslides controlled by winter precipitation to reactivations controlled by spring temperatures therefore this contribution also adds evidence to the hypothesis that climate change and related warmer springs could further enhance landslide activity in the course of the 21 st century

the multirisk platform the technical concept and application of a regional scale multihazard exposure analysis tool many regions worldwide are threatened by multiple natural hazards with the potential to cause high damages and losses however the modeling of multiple hazards in a joint analysis scheme is still in the early stages of development as a range of serious challenges emerges in the multihazard context such as differing modeling approaches in use for contrasting hazards the time and data demanding conduct of each single preparative intermediate and analysis step and the clear visualization of the modeling outcome under consideration of these difficulties a regional multihazard exposure analysis concept is developed for five natural hazards debris flows rock falls shallow landslides avalanches and river floods complemented by a visualization scheme to present the modeling outcome an automation of the two schemes resulted in a beta version of the multirisk modeling and the multirisk visualization software tool forming together the multirisk platform to test the analysis scheme and the software implementation of multirisk a case study is performed in the barcelonnette basin in france with a worst case parameterization of the models on the basis of extensive literature reviews experiences from this case study offered many insights into the multihazard topic and even more questions e g with respect to coherent multihazard model parameterization validation or the comparability and interpretation of single hazard modeling results respectively although analysis schemes can be proposed and software tools can be provided to facilitate many steps a well conceived and reflective approach to multihazard settings is essential the worst case analysis based on literature values apparently leads to an overestimation of the susceptible areas and the number of exposed elements nevertheless depending on the data situation of an area especially in areas without any information on past events this approach may offer the determination of general hazard distributions overlaps and areas of potential risk without data demanding calibration

geochemical and petrological evidence of the subduction of delaminated adriatic continental lithosphere in the genesis of the neogene quaternary magmatism of central italy abstract serri g innocenti f and manetti p 1993 geochemical and petrological evidence of the subduction of delaminated adriatic continental lithosphere in the genesis of the neogene quaternary magmatism of central italy in m j r wortel u hansen and r sabadini editors relationships between mantle processes and geological processes at or near the earth s surface tectonophysics 223 117 147 the neogene quaternary magmatism of the northern apenninic arc took place in four phases separated in space and time which become progressively younger from west to east phase i 14 ma phase ii 7 3 6 0 ma phase iii 5 1 2 2 ma phase iv 1 3 0 1 ma this magmatism is the result of the activation of three physically separate sources 1 the adriatic continental crust extracted from the mantle in the late proterozoic 2 a strongly refractory recently k enriched harzburgitic mantle located in the mechanical boundary layer mbl of the lithosphere and 3 a recently metasomatized cpx rich mantle compositionally variable from iherzolite to wehrlite clinopyroxenite interpreted as an ephemerally k enriched asthenosphere the adriatic continental crust is the dominant source of the acid plutonic and volcanic rocks of the tuscan region the acid magmatism is mostly found inside an ellipsoidal area about 150 300 km centred on giglio island here defined as the tuscan crustal dome within this area mantle derived magmas unaffected by important crustal contamination processes and mixing with crustal anatectic melts have so far not been found pure crustal magmas are rare but are represented for example by some of the san vincenzo and roccastrada rhyolites virtually all the tuscan acid centres show evidence of mixing with potassic mantle derived magmas major and trace elements as well as 87 sr 86 sr and 143 nd 144 nd data on primitive rocks mg 65 reveal two groups of mantle derived magmas these define two distinct mantle enrichment trends both essentially due to the additions of k rich components which metasomatized separate compositionally diverse upper mantle sectors in both cases the most remarkable mineralogical effect of these enrichment processes is the production of variable amount of phlogopite through reaction between fluids and or melts with the mantle the rocks of group i ol hy and q normative lamproites ultrapotassic high mg latites ultrapotassic shoshonites and shoshonites saturated trend are considered to be derived by partial melting at low pressure 87 sr 86 sr 0 717 ce sr 0 3 and k 2 o na 2 o 6 7 and low ratios of 143 nd 144 nd 0 5121 0 5120 and ba la 87 sr 86 sr 0 712 and k 2 o na 2 o 8 9 values and low 143 nd 144 nd ba la 0 10 ratios these constraints do not allow to exclude a complete identity between the k rich components which metasomatized the mantle sources of the saturated and undersaturated trend magmas the geochemical and isotopic features of the components that metasomatized the mantle sources of the northern apenninic arc magmatism can be explained by a geodynamic process which causes a large amount of crustal materials to be incorporated within the upper mantle we propose that the delamination and subduction of the adriatic continental lithosphere related to the still ongoing northern apennine continental collision provide a viable mechanism to explain the genesis and eastward discontinuous migration of the magmatism in central italy the subduction of delaminated lithospheric mantle with lower crustal slivers would have exposed uppermost mantle adriatic mbl and crustal units previously imbricated in the apennine chain to the heating advected by the upwelling of a recently and ephemerally k enriched asthenospheric mantle wedge and by the underplating of magmas derived from it we consider that the diapiric uprising of a hot crustally contaminated asthenosphere occurs in the wake left above the sinking of the adriatic delaminated subducting continental lithosphere the delamination subduction process of the adriatic lithosphere has probably started in the early middle miocene but earlier than 15 14 ma ago as indicated by the age and petrologic characteristics of the first magmatic episode sisco lamproite of the northern apennine orogenesis

na k ion exchange reaction between rhyolitic glass and na k c1 aqueous solution under hydrothermal conditions abstract hydrothermal experiments on ion exchange reactions were carried out using synthetic and natural rhyolitic glasses and na k cl aqueous solution at 200 300 c and 1000 bars the rhyolitic glass did not crystallize during the reaction even under hydrothermal conditions and it behaved as a na k ion exchanger the na k ion exchange properties of the glass were strongly influenced by its thermal history quenched glass preferentially fixed k rather than na and glass obtained by slow cooling showed the opposite trend the present experimental results show clearly that glass as well as minerals can control the composition of the coexisting aqueous solution in hydrothermal systems the present results also suggest that the chemical composition of coastal thermal waters in japan is controlled by the two stage episode of reaction between acidic volcanic rocks and seawater

landslide susceptibility assessment by bivariate methods at large scales application to a complex mountainous environment statistical assessment of landslide susceptibility has become a major topic of research in the last decade most progress has been accomplished on producing susceptibility maps at meso scales 1 50 000 1 25 000 at 1 10 000 scale which is the scale of production of most regulatory landslide hazard and risk maps in europe few tests on the performance of these methods have been performed this paper presents a procedure to identify the best variables for landslide susceptibility assessment through a bivariate technique weights of evidence woe and discusses the best way to minimize conditional independence ci between the predictive variables indeed violating ci can severely bias the simulated maps by over or under estimating landslide probabilities the proposed strategy includes four steps i identification of the best response variable rv to represent landslide events ii identification of the best combination of predictive variables pvs and neo predictive variables npvs to increase the performance of the statistical model iii evaluation of the performance of the simulations by appropriate tests and iv evaluation of the statistical model by expert judgment the study site is the north facing hillslope of the barcelonnette basin france affected by several types of landslides and characterized by a complex morphology results indicate that bivariate methods are powerful to assess landslide susceptibility at 1 10 000 scale however the method is limited from a geomorphological viewpoint when rvs and pvs are complex or poorly informative it is demonstrated that expert knowledge has still to be introduced in statistical models to produce reliable landslide susceptibility maps

k m cuffey and w s b paterson 2010 the physics of glaciers fourth edition amsterdam etc academic press 704pp isbn 10 0 123694 61 2 isbn 13 978 0 123 69461 4 hardback 60 99 71 95 us 99 95

the temporal stability and activity of landslides in europe with respect to climatic change teslec main objectives and results abstract the major aim of the european project the temporal stability and activity of landslides in europe with respect to climatic change teslec was to investigate the interrelationship between landslides climate and time the research was focused on three main objectives 1 developing criteria for the recognition of landslides 2 reconstructing past distributions of landslide incidents and their relationship to climatic change parameters and 3 developing a hydrological and slope stability modelling framework using different test sites the results of the project are related to these major objectives and include 1 a technical manual for landslide recognition 2 records of landslide activity and 3 an evaluation of different hydrological and slope stability models landslide activity since 1950 has been generally high at all test sites in some areas there has almost been a continuous activity observed since the beginning of the monitoring the records before 1950 are incomplete and probably indicate a lack of data rather than a lack of landslide activity whether the observed active landslides are carrying a climate signal cannot be stated for all test sites with high confidence since some relationships between climate and landslides are uncertain thus for the present the complexity of the relationships between climate and landsliding seems to make it not feasible to establish universal laws all over europe on the other hand it was possible to establish for some areas a cumulative rainfall duration threshold for the reactivation of landslides future scenarios of regional precipitation were derived from downscaled general circulation model gcm experiments and used within simple slope hydrological and slope stability models the evaluation of hydrological and slope stability models shows that physically based models are not always the best solution due to the model complexity and data requirements for shallow landslides more simple tank models are sometimes the better alternative future model development should strengthen considerations of fissure flow sudden changes in permeability larger landslide volumes and complex landslide topography

morphology and sedimentology of a complex debris flow in a clay shale basin coupling morphological sedimentological and rheological studies to numerical simulations is of primary interest in defining debris flow hazard on alluvial fans in particular numerical runout models must be carefully calibrated by morphological observations this is particularly true in clay shale basins where hillslopes can provide a large quantity of poorly sorted solid materials to the torrent and thus change both the mechanics of the debris flow and its runout distance in this context a study has been completed on the faucon stream southeastern french alps with the objectives of 1 defining morphological and sedimentological characteristics of torrential watersheds located in clay shales and 2 evaluating through a case study the scouring potential of debris flows affecting a clay shale basin morphological surveys grain size distributions and petrographic analyses of the debris flow deposits demonstrate the granular character of the flow during the first hectometre and its muddy character from there to its terminus on the debris fan these observations and laboratory tests suggest that the contributing areas along the channel have supplied the bulk of the flow material copyright 2005 john wiley sons ltd

alice assessment of landslides induced by climatic events a single tool to integrate shallow and deep landslides for susceptibility and hazard assessment abstract the increasing evolution of urban areas in landslide prone regions and the modification of precipitation due to global climate change have led to a growing need for landslide hazard assessment lha for local land management and security services lha is based on the definition of the spatial and temporal probability of landslide occurrences and is split into three steps i a phenomenon inventory ii a landslide susceptibility analysis and iii a landslide hazard analysis nevertheless in practice essential information is often missing and lha corresponds most of the time to landslide susceptibility assessment acquired by expert knowledge this article presents a physical based model alice assessment of landslides induced by climatic events that can integrate different types of landslides shallow and deep with different sizes this tool can be used at the meso or broader scale 1 25 000 to 1 10 000 of work according to expert knowledge however a calibration must be carried out to fit observations and to take uncertainties into account thus a specific strategy is applied to the model on a study site located in the french south alps where numerous different landslide types were observed and analyzed after calibration on a small representative area the best fitted parameters are applied to a larger area for different types of landslides three landslide susceptibility maps shallow translational landslides rotational landslides and complex landslides are produced and the different susceptibility classes are compared with a landslide susceptibility map produced by a geomorphological approach the different susceptibility envelopes computed by the model are well integrated into the high susceptibility envelopes defined by the so called expert geomorphological approach thus the tool makes it possible to improve the mapping of potentially unstable areas by taking into account parameters such as the groundwater level in different surficial formations or the geotechnical values of landslide prone formations that experts are not always able to integrate alice is therefore proven to be a useful tool for mapping potential landslide prone areas if the tool is well calibrated taking into account the expert vision of the field different landslide types and different triggering factors including rainfall and seismic acceleration

geologic topographic and climatic controls in landslide hazard assessment using gis modeling a case study of souk ahras region ne algeria abstract landslides are the most common hazard in mountainous regions of northeast algeria in this study landslide hazard zonation of souk ahras province was carried out using a raster based gis and statistical processing landslide locations were defined from interpretation of aerial photographs and field surveys rotational planar and complex landslides were identified to reveal the controlling factors of landslides a temporal distribution of 603 recognized landslides 1981 2011 is compared with the monthly precipitation variation indicating a strong correlation between precipitation and landslide occurrence the correlation between landslide and lithology slope angle and elevation shows the same results tabular data maps and satellite images were collected processed and constructed into a spatial database in a gis platform the factors that influence landslide occurrence such as slope angle slope exposition and elevation were derived from the dem lithology soil deposits and faults were digitalized from the geologic maps roads streams and timber were extracted from landsat image precipitation was krigged from pluviometric measurement dataset different classes of thematic layers were assigned a corresponding rating value as attribute information and an attribute map was generated for each data layer in the gis landslide hazard areas were assessed and mapped using the landslide occurrence and permanent factor maps by applying a probabilistic method with a logistic regression approach the results of the analysis were verified using landslides location map compared with the probability model the resulting map can be used to mitigate this hazard and to plan land use and urbanization

landslides and climatic conditions in the barcelonnette and vars basins southern french alps france research into the climatic causes behind the triggering and reactivation of landslides has been carried out in two basins in the southern french alps where a great many landslides have occurred over more than a century correlations between landslides and climate are sometimes precise and closely related in time at other times imprecise and more distant the better known the type of landslide and the date of its occurrence the greater the correlation may appear be this as it may climate is never the sole cause this paper deals with the limits of the effects of climate

morphological and kinematic evolution of a large earthflow the montaguto landslide southern italy article ml ong earthflow in the southern apennines of italy following an analysis of th ed ifferent methods and techniques available to measure surface modifications caused by a large earthflow we selected a combination of monitoring techniques com patible with the montaguto case study we exploited i visual interpretation of aerial and satellite imagery ii quantitative analysis of six digital elevation model s dems covering the landslide area and iii al arge set of high accuracy three dimensional topographic measurements captured by three robotised total stations rtss in tegration of the results obtained from the different monitoring techniques allowed us to investigate the long multi decadal and short seasonal term evolution of the montaguto earthflow in the 58 year period 1954 2011 the examination of the available aerial satellit ea nd hill shade images revealed ac yclic long term behaviour of mass movements of different types in the rio nocelle catchment occupied by the recent montaguto earthflow the combined analysis of the six dems allowed measuring the material eroded from the landslide crown area v 1 4 10 6

sedimentary record of a scandinavian ice sheet drainage system and till deposition over subglacial obstacles promoting basal sliding an example from southern poland abstract subglacial obstacles occurring in the path of advancing ice sheets generally generate higher longitudinal compression and higher frictional drag than a flat substrate however in the case of a soft sediment substratum they can have a very different effect on ice sheet behaviour this study concerns a substrate composed of very fine grained sediments with low permeability the relationship between subglacial obstacles and the overriding scandinavian ice sheet was studied in an area of southern poland where a small intervalley neogene clay ridge 40 m high was present based on sedimentological and structural analysis of subglacial till and gravelly sandy sediments the basal depositional processes and subglacial conditions and their influence on ice sheet behaviour were analysed the till and related deposits within the ridge reflecting high water pressure conditions and lack of glacitectonic deformations indicate that the clay ridge did not generate much resistance against the advancing ice sheet but instead favoured basal slip the impermeable substratum weakened the ice bed coupling and promoted ice detachment from the substratum gravelly sandy inclusions at the till clay contact indicate that during the first stage of ice sheet overriding a canal drainage system developed at the ice substrate interface varied geometry size and location of inclusions of sorted sediments suggest periodic instability of the canal system which could lead to its transformation from initially uniform to being composed of conduits of different sizes during later stages of ice sheet overriding a traction till was deposited and occasional drainage through a water film was sufficient to evacuate basal meltwater the resulting change in the character of subglacial drainage was probably related to variations in water pressure gradient during progressive ice sheet advance

observation and analysis of ice flow in the largest greenland ice stream we have applied satellite radar interferometry methods to map the velocity field of the recently discovered northeast greenland ice stream we have used these data in conjunction with ice thickness and accumulation data to determine that the ice stream is in balance within the measurement errors we used control methods to invert a finite element model of ice sheet flow constrained by the data to infer the ice stream s basal shear stress distribution our results reveal that flow in a section of the downstream end has much in common with the streaming flow of the ross ice streams of west antarctica e g a weak bed and fast flow in the presence of low driving stresses for several hundred kilometers along the middle of the ice stream the basal shear stress balances the driving stress in the upstream area where the ice stream is first visible in the velocity data the bed appears to be weak which may contribute to the initiation of the ice stream

dendrogeomorphological analysis of mass movement a technical note on the research method dating of mass movement events by examining the course of eccentricity of the annual rings of trees inclined as a result of these movements can be a problem in the case of multiple inclined trees showing compound trunk curvature and complex reaction wood these problems however can be solved when sampling of ring width cores is based on accurate analysis of the form of the trunk

high magnitude landslide events on a limestone scarp in central germany morphometric characteristics and climatic controls abstract there are both internal and external controlling factors leading to slope instability and susceptibility to mass movement processes this paper explores which external climatic variables of different temporal scales influence the occurrence of high magnitude landslide events the investigations were focused on the wellenkalk cuesta scarp in the thuringia basin thuringer becken in central germany the cuesta scarp is composed of a densely jointed limestone caprock wellenkalk and impermeable mudstones and marls of the upper bunter sandstone rot in the lower part of the slope mass movements are a typical feature of the wellenkalk scarp the entire scarp slope length 1000 km has been systematically mapped and investigated in a comprehensive research project in order to provide reliable information on the spatial distribution and control of the mass movements more than 20 of the scarp slope has been influenced by various types of holocene mass movements with strong differences in spatial frequencies sixteen high magnitude landslides sturzfliesungen were identified by field inspection and mapping of slope geomorphology information on locations morphometric characteristics stratigraphic positions and rainfall related attributes of the scarp slopes affected by the large landslides is presented mean annual rainfall amounts decrease from more than 800 mm in the western part of the basin to less than 550 mm in the east meteorological statistics on the spatial distribution of heavy rainfall intensities of different durations and return periods show that greatest precipitation intensities in short events 1 h are reached at the western margin differences in rainfall intensities between the western and eastern parts decrease with increasing duration of the events where available event related meteorological information was collected the spatial distribution of the landslides is most closely mirrored in the pattern of mean annual precipitation though this variable is generally not thought to be a satisfactory or reliable climatic controlling factor no landslides occur below a threshold value of 700 mm the empirical data show that some general level of average perennial water input into the slope system seems to be of decisive importance for the occurrence of high magnitude mass movements only when the precondition of a more general hydrological disposition is fulfilled a direct triggering of high magnitude mass movements by a short time intensive rainfall period or event can become effective

characterizing landslides through geophysical data fusion example of the la valette landslide france many studies show that certain geophysical methods such as seismic and electrical resistivity imaging appear to be well adapted for investigating the internal structures of landslides and understanding the related hydro mechanical mechanisms these are methods that allow the direct and non intrusive measurement of acoustic p and shear s wave velocities and electrical resistivity which are three physical parameters considered as essential for estimating the mechanical properties of moving reworked material we applied these techniques to the la valette landslide southern french alps a typical example of an intra material landslide carrying out measurements simultaneously along two profiles 400 m and 300 m long and respectively perpendicular to and along the slide direction we then used suitable inversion algorithms to estimate both the p and s wave velocity fields and the electrical resistivity field from the recorded data the results aided by field surface observations show that a correlation exists between the state of the material and the seismic velocity and or electrical resistivity data thus confirming that the simultaneous use of the two methods provides complementary information on the geomechanical behavior of the landslide more particularly the seismic data provide information on fissure density variations and the presence of shear bent material whereas the electrical resistivity data provide information on the groundwater content to enable a more integrated petrophysical interpretation we applied a data fusion strategy based on fuzzy subsets to the geophysical datasets through combining the tomograms we identified a surface layer of soft material along the two profiles the bottom of this layer was also recognized in a borehole from a methodological point of view the results show the applicability of adopting geomechanical hypotheses as inputs of geophysical data fusion for identifying areas where sediment mobilization could occur

mass movements and tree rings a guide to dendrogeomorphic field sampling and dating abstract trees affected by mass movements record the evidence of geomorphic disturbance in the growth ring series and thereby provide a precise geochronological tool for the reconstruction of past activity of mass movement the identification of past activity of processes was typically based on the presence of growth anomalies in affected trees and focused on the presence of scars tilted or buried trunks as well as on apex decapitation for the analyses and interpretation of disturbances in tree ring records in contrast clear guidelines have not been established with largely differing or no thresholds used to distinguish signal from noise at the same time processes with a large spatial footprint e g snow avalanches landslides or floods will likely leave growth anomalies in a large number of trees whereas a falling rock would only cause scars in one or a few trees along its trajectory based on the above considerations we examine issues relating to the interpretation and dendrogeomorphic dating of mass movements particular attention is drawn to sampling in terms of sample distribution across a study site the actual selection of trees as well as to sample size i e number of trees sampled based on case studies from snow avalanche debris flow and landslide sites we demonstrate that thresholds can indeed improve dating quality and at the same time minimize noise in time series we also conclude that different thresholds need to be used for different processes and different periods of the reconstruction especially for the early stages of the reconstruction when the number of potentially responding trees will be much smaller this paper seeks to set standards for dendrogeomorphic fieldwork analysis and interpretation for different processes of mass movements

landslides triggered in weathered crystalline rocks of moderate latitudes a case study in mediterranean environment the maures massif france abstract the main purpose of this study is to characterize shallow and moderately deep landslide prone materials in crystalline rocks at moderate latitudes the procedure is based by a four step approach coupling the geomorphological approach the geotechnical approach and slope stability analyses based on limit equilibrium equations firstly different weathering horizons were identified with different thicknesses and characteristics depending on the original lithology these observations led to the development of a weathering model with two steps a regional paleo weathering step and a geomorphological weathering step secondly conceptual models of weathered horizon thicknesses were created according to the lithological context these models led to the identification of three major weathering types thirdly slope stability models were computed for three types of weathered lithology favourable theoretically to slope failure granit micaschists gneiss for each case the different models properly computed landslide occurrences and their locations for highly saturated weathered materials that corresponded to field observations to finalize the study a first analysis of precipitation data was carried out to define some triggering trends for slope failures in this environment therefore based on this simple approach it is possible to define some trends for shallow and moderately deep landslides in weathered crystalline environment located in moderate latitudes with mediterranean climate finally the information can be used by end users and practitioners for public works management on these slopes

slope instability in relation to glacial debuttressing in alpine areas upper durance catchment southeastern france evidence from field data and 10be cosmic ray exposure ages the upper durance catchment is an area prone to rock slope failures such failures reflect the combination of high relief litho structural controls and paraglacial stress release the aim of this study is to determine the role of deglacial unloading and resulting paraglacial stress release in conditioning or triggering slope failure former dimensions of the durance glacier are reconstructed then combined with digital elevation model data in a raster geographic information system to quantify the spatial pattern of stresses associated with glacial loading at the last glacial maximum preliminary calculations suggest that major rock falls and rock avalanches are associated with areas subject to the highest decompression stresses focus on two case studies allows the consequences of paraglacial stress release on slope instability to be evaluated description of slope failure runout deposits allows reconstruction of the nature of slope failure surface exposure dates based on concentration of cosmogenic 10be allows the timing of both deglaciation and that of post glacial rock slope failures to be established it is shown that rock slope failures are concentrated on lower valley side slopes within the area occupied by ice at the last glacial maximum and that their locations coincide with zones of inferred high glacial loading stress consistent with interpretation of both bedrock disruption and large scale rock slope failures as paraglacial phenomena induced by stress release following deglaciation timing of initial rock avalanche runout deposition at one site is consistent with this conclusion though later instability episodes at the same site may have occurred independent of the influence of paraglacial stress release

triggering conditions and mobility of debris flows associated to complex earthflows landslides on black marl slopes of the french alps are in most cases complex catastrophic failures in which the initial structural slides transform into slow moving earthflows under specific hydrological conditions these earthflows can transform into debris flows due to their sediment volume and their high mobility debris flow induced by landslides are far much dangerous than these resulting from continuous erosive processes a fundamental point to correctly delineate the area exposed to debris flows on the alluvial fans is therefore to understand why and how some earthflows transform into debris flow while most of them stabilize in this paper a case of transformation from earthflow to debris flow is presented and analysed an approach combining geomorphology hydrology geotechnics and rheology is adopted to model the debris flow initiation failure stage and its runout postfailure stage using the super sauze earthflow alpes de haute provence france as a case study the objective is to characterize the hydrological and mechanical conditions leading to debris flow initiation in such cohesive material results show a very good agreement between the observed runout distances and these calculated using the debris flow modeling code cemagref 1 d the deposit thickness in the depositional area and the velocities of the debris flows are also well reproduced furthermore a dynamic slope stability analysis shows that conditions in the debris source area under average pore water pressures and moisture contents are close to failure a small excess of water can therefore initiate failure seepage analysis is used to estimate the volume of debris that can be released for several hydroclimatic conditions the failed volumes are then introduced in the cemagref 1 d runout code to propose debris flow hazard scenarios results show that clayey earthflow can transform under 5 year return period rainfall conditions into 1 km runout debris flow of volumes ranging between 2000 to 5000 m 3 slope failures induced by 25 year return period rainfall can trigger large debris flow events 30 000 to 50 000 m 3 that can reach the alluvial fan and cause damage

airborne laser scanning of forested landslides characterization terrain model quality and visualization abstract mapping complex landslides under forested terrain requires an appropriate quality of digital terrain models dtms which preserve small diagnostic features for landslide classification such as primary and secondary scarps cracks and displacement structures flow type and rigid type optical satellite imagery aerial photographs and synthetic aperture radar images are less effective to create reliable dtms under tree coverage here we utilized a very high density airborne laser scanning als data with a point density of 140 points m 2 for generating a high quality dtm for mapping landslides in forested terrain in the barcelonnette region the southern french alps we quantitatively evaluated the preservation of morphological features and qualitatively assessed the visualization of als derived dtms we presented a filter parameterization method suitable for landslide mapping and compared it with two default filters from the hierarchical robust interpolation hri and one default filter from the progressive tin densification ptd method the results indicate that the vertical accuracy of the dtm derived from the landslide filter is about 0 04 m less accurate than that from the ptd filter however the landslide filter yields a better quality of the image for the recognition of small diagnostic features as depicted by expert image interpreters several dtm visualization techniques were compared for visual interpretation the openness map visualized in a stereoscopic model reveals more morphologically relevant features for landslide mapping than the other filter products we also analyzed the minimal point density in als data for landslide mapping and found that a point density of more than 6 points m 2 is considered suitable for a detailed analysis of morphological features this study illustrates the suitability of high density als data with an appropriate parameterization for the bare earth extraction used for landslide identification and characterization in forested terrain

probability maps of landslide reactivation derived from tree ring records pra bellon landslide southern french alps probability maps of landslide reactivation are presented for the pra bellon landslide located in the southern french alps based on results obtained with dendrogeomorphic analysis spatiotemporal patterns of past landslide activity was derived from tree ring series of 403 disturbed mountain pine trees growing in the landslide body in total 704 growth disturbances were identified in the samples indicating 22 reactivation phases of the landslide body between 1910 and 2011 the mean return period was 4 5 years given the spatiotemporal completeness of the reconstruction probabilities of landslide reactivation were computed and illustrated using a poisson distribution model and for 5 20 50 and 100 years probability of landslide reactivation is highest in the central part of the landslide body and increases from 0 13 for a 5 year period to 0 94 for a 100 year period conversely probabilities of reactivation are lower at its margins the proposed method differs from conventional approaches based on statistical analyses or physical modeling that have demonstrated to have limitations in the prediction of spatiotemporal reactivation of landslides our approach is in contrast based on extensive data on past landslides and therefore allowed determination of quantitative probability maps of reactivation derived directly from the frequency of past events this approach is considered a valuable tool for land managers in charge of protecting and forecasting people and their assets from the negative effects of landslides as well as for those responsible for land use planning and management it demonstrates the reliability of dendrogeomorphic mapping that should be used systematically in forested shallow landslides

progressive alkali ion exchange with stratigraphic position in a pyroclastic cooling unit mt torro sabatini central italy abstract significant variation of k 2 o na 2 o ratios and total alkali contents elevated loss on ignition 12 16 wt values and elevated fe 3 fe 2 are shown in new data from a road cut profile of pyroclastic rocks in an area of young ultra potassic rocks decreasing k 2 o na 2 o ratios and total alkali contents are systematically related to stratigraphic position being most pronounced at the centre of the deposit probably because of the slower cooling rate pumice bombs are less altered than ash but show the same variation pattern except for the alkalis hydration and the oxidation state of iron the geochemical compositions of the rocks are unchanged

frequency of debris flows and their relation with precipitation a case study in the central alps italy abstract debris flows are very important and widespread mass movements and represent a remarkable geomorphological hazard this research deals with debris flows in an alpine environment studied using dendrogeomorphological dating techniques outlining their relation with precipitation and analysing possible changes in their frequency and intensity over time the study area is the upper valle del gallo northern italy a typical high mountain environment dominated by mass wasting processes where many debris flow fans occupy the valley bottom dendrogeomorphological research was conducted on twelve of these fans and two channels located on slopes tree growth anomalies abrasion scars compression wood and abrupt growth changes were used as dating methods two hundred and thirty nine debris debris flow events between 1875 and 2003 were dated using 757 trees pinus montana mill analysis between dated events and precipitation suggests that debris flows in the study area could be triggered by 20 30 mm of rain concentrated in a few hours the debris flow frequency tends to increase gradually but the highest value seems to have occurred in the period 1974 1983 this trend agrees with the historical occurrence of flooding events in northern italy as inferred by literature and with similar studies conducted in the swiss alps the results of this research are intended as a contribution for understanding the response of geomorphological processes to climatic changes

instability conditions of marly hillslopes towards landsliding or gullying the case of the barcelonnette basin south east france abstract black marl hillslopes in the french alps are strongly affected either by mass movements or by gully erosion due to their susceptibility to weathering processes this paper presents experimental data geomorphological geotechnical geomechanical and hydrological on the parameters of the material of three well known earthflows and of the two stratigraphic parts of the callovo oxfordian black marl the main objectives are to define the geomechanical behaviour of the various formations using different characterisations grain size distribution mineralogy retention capacity consolidation test direct shear test and triaxial test and to demonstrate how such soils can affect the stability of natural slopes particular care must be taken when interpreting the geomechanical tests on this evolving and very heterogeneous clay rich material there are strong relationships between the parent rock and the landslide materials this paper presents a conceptual model of the development of strength over a period of time and investigates the parameters of the material for use in slope stability analysis and risk assessment

high resolution fingerprints of past landsliding and spatially explicit probabilistic assessment of future reactivations aiguettes landslide southeastern french alps the purpose of this study was to reconstruct spatio temporal patterns of past landslide reactivation and the possible occurrence of future events in a forested area of the barcelonnette basin southeastern french alps analysis of past events on the aiguettes landslide was based on growth ring series from 223 heavily affected mountain pine pinus uncinata mill ex mirb trees growing on the landslide body a total of 355 growth disturbances were identified in the samples indicating 14 reactivation phases of the landslide body since ad 1898 accuracy of the spatio temporal reconstruction is confirmed by historical records and aerial photographs logistic regressions using monthly rainfall data from the histalp database indicated that landslide reactivations occurred due to above average precipitation anomalies in winter they point to the important role of snow in the triggering of reactivations at the aiguettes landslide body in a subsequent step spatially explicit probabilities of landslide reactivation were computed based on the extensive dendrogeomorphic dataset using a poisson distribution model for an event to occur in 5 20 50 and 100 yr high resolution maps indicate highest probabilities of reactivation in the lower part of the landslide body and increase from 0 28 for a 5 yr period to 0 99 for a 100 yr period in the upper part of the landslide body probabilities do not exceed 0 57 for a 100 yr period and somehow confirm the more stable character of this segment of the aiguettes landslide the approach presented in this paper is considered a valuable tool for land use planners and emergency cells in charge of forecasting future events and in protecting people and their assets from the negative effects of landslides