revised palaeoclimatic significance of mueller glacier moraines southern alps new zealand a sequence of late holocene moraines on the foreland of the mueller glacier southern alps new zealand forms part of a local moraine age database used to establish a regional glacier chronology and subsequently to investigate potential intra hemispheric and global climate forcing mechanisms we present new sedimentological and geomorphological evidence that a set of these moraine ridges previously considered to represent individual advances constitutes a single moraine complex the mueller memorial moraine formed by supraglacial transport of a large volume of landslide debris to the glacier terminus because a moraine formed in this way is not necessarily associated with an advance triggered by a climate event we question the palaeoclimatic significance of the mueller memorial moraine as well as that of other moraines in comparable settings our findings suggest that the mode of formation and glacio dynamical context of moraines whose ages contribute to existing palaeoclimate reconstructions need to be re examined in order to assess the reliability of these reconstructions copyright 2015 john wiley sons ltd

long runout rockslide on glacier at tsar mountain canadian rocky mountains potential triggers seismic and glaciological implications a rhomboidal shaped rockslide with a length of 2 2 km and an area of 1 35 km2 covers 30 of a small clemenceau icefield group cirque glacier by means of remote sensing airborne photography climate and seismic data analysis the extent timing possible trigger mechanisms and rockslide effects on the glacier are discussed an ml 2 0 seismic event on 14 september 2000 represents the rockslide and has a spindle shaped waveform and high energy in the low frequencies based on a strong signal duration of 56 108 seconds the rockslide had an average runout velocity of 22 45 m s 1 stress fatigue and a combination of rain and snow followed by rapid melt and night time freezing could have co triggered the slide additional seismic events with epicentres 40 km from the cirque were recorded 26 times since 1985 and range between ml 0 9 3 3 but none were caused by or triggered large mass movement with a rock source volume of 1 6 106 m3 and a deposited volume of 2 4 106 m3 the sum of bulking and entrainment is between 25 and 150 five melt seasons post event levees 20 30 m wide tower 30 m over the surrounding glacier rockslide characteristics and its fahrboschung of 15 height length h l 0 28 indicate that this rockslide is quite typical for long runout rockslides on glaciers however the basal friction coefficient was higher than found on other glaciers and could relate to the presence of medial moraines transverse to the flowline and to pre slide debris cover the difference between the coefficient of friction in the main flowline 0 11 0 14 and that in a lobe confined between two medial moraines 0 065 suggests that confinement increases mobility by 70 115 apart from reduced ablation under the rock debris effects of the rockslide on the glacier were minimal copyright 2010 john wiley sons ltd

geomorphology and weathering characteristics of erratic boulder trains on tierra del fuego southernmost south america implications for dating of glacial deposits abstract erratic boulder trains ebts are a useful glacial geomorphological feature because they reveal former ice flow trajectories and can be targeted for cosmogenic nuclide exposure dating however understanding how they are transported and deposited is important because this has implications for palaeoglaciological reconstructions and the pre exposure and or erosion of the boulders in this study we review previous work on ebts which indicates that they may form subglacially or supraglacially but that large angular boulders transported long distances generally reflect supraglacial transport we then report detailed observations of ebts from tierra del fuego southernmost south america where their characteristics provide a useful framework for the interpretation of previously published cosmogenic nuclide exposure dates we present the first comprehensive map of the ebts and analyse their spatial distribution size and physical appearance results suggest that they were produced by one or more supraglacial rock avalanches in the cordillera darwin and were then transported supraglacially for 100 s of kilometres before being deposited rock surface weathering analysis shows no significant difference in the weathering characteristics of a sequence of ebts previously hypothesized to be of significantly different age i e different glacial cycles we interpret this to indicate that the ebts are much closer in age than previous work has implied this emphasises the importance of understanding ebt formation when using them for cosmogenic nuclide exposure dating

glaciers and mass wasting processes their influence on the shaping of the kali gandaki valley higher himalaya of nepal abstract this paper addresses the question of the respective role of glaciers and mass wasting processes in the shaping of the high valleys of the central himalaya this is a region in which the himalayan range is at its narrowest and where it is cut by the deepest gorge in the world the kali gandaki valley following a brief description of the region and of the criteria used to discriminate between both sets of processes some specific sites that have given rise to divergent interpretations are discussed it is shown that undoubted evidence of past glaciation is rare and that most of the diamictons observed today are best interpreted as the products of deep seated landslides and or catastrophic debris flows of large magnitude and probably low frequency spanning the period from the last glacial maximum to the holocene the modalities of this evolution cast some doubt on some former reconstructions of past glacial extents moreover the continuous reworking of this material continues to influence the nature and current rates of erosion

friction and dynamics of rock avalanches travelling on glaciers rock avalanches travelling on glaciers often exhibit effective friction coefficient lower than those on a rocky terrain after briefly considering some data of rock avalanches on glaciers the physics of sliding of solid objects on icy surfaces is reviewed and a model is put forward for the mechanics of rock avalanche sliding on ice accounting for the formation of a natural lubricating layer it is suggested that at the beginning of the flow of a rock avalanche friction results from rocky blocks ploughing on ice as the erosion continues a gouge of ice particles results which clogs the interstices between blocks and may partially melt as a consequence of the production of frictional heat this conceptual model is numerically investigated for a slab travelling on ice the results show an increase in mobility as a function of slab thickness travelled length and the gravity field in agreement with case studies the results are useful to interpret the peculiar features of rock avalanches travelling on icy surfaces such as digitations out runner blocks and longitudinal furrows the lubrication theory for landslides on ice proposed here may provide a framework for understanding landslides on earth and for future modelling in addition it may help elucidate the presence of similar landslide deposits on the surface of mars

supra glacial deposition and flux of catastrophic rock slope failure debris south central alaska the ongoing debate over the effects of global environmental change on earth s cryosphere calls for detailed knowledge about process rates and their variability in cold environments in this context appraisals of the coupling between glacier dynamics and para glacial erosion rates in tectonically active mountains remain rare we contribute to filling this knowledge gap and present an unprecedented regional scale inventory of supra glacial sediment flux and hillslope erosion rates inferred from an analysis of 123 large 0 center dot 1km2 catastrophic bedrock landslides that fell onto glaciers in the chugach mountains alaska as documented by satellite images obtained between 1972 to 2008 assuming these supra glacial landslide deposits to be passive strain markers we infer minimum decadal scale sediment yields of 190 to 7400tkm 2yr 1 for a given glacier surface cross section impacted by episodic rock slope failure these rates compare to reported fluvial sediment yields in many mountain rivers but are an order of magnitude below the extreme sediment yields measured at the snouts of alaskan glaciers indicating that the bulk of debris discharged derives from en glacial sub glacial or ice proximal sources we estimate an average minimum para glacial erosion rate by large episodic rock slope failures at 0 center dot 5 0 center dot 7mmyr 1 in the chugach mountains over a 50 yr period with earthquakes likely being responsible for up to 73 of this rate though ranking amongst the highest decadal landslide erosion rates for this size of study area worldwide our inferred rates of hillslope erosion in the chugach mountains remain an order of magnitude below the pace of extremely rapid glacial sediment export and glacio isostatic surface uplift previously reported from the region

river profiles along the himalayan arc as indicators of active tectonics abstract longitudinal profiles along sixteen major transverse himalayan rivers add important constraints to models of active continental subduction and its evolution these profiles are characterized by a zone of relatively high gradient that cannot be associated with differential resistence to erosion in all cases the base of the zone of increased gradients correlates with 1 the topographic front between the lesser and high himalayas 2 the narrow belt of intermediate magnitude thrust earthquakes 3 the main central thrust zone mct these features define a small circle in the central portion of the himalayan arc these correlations suggest that the discontinuity in the river profiles and the other features are controlled by a major tectonic boundary between the rising high himalayas and the lesser himalayas no sharp increases in gradient are observed near the main boundary thrust mbt except on a few rivers such as the jhelum or kundar where the mbt lies close to both the mct and the seismic belt thus it is unlikely that the mbt is a major tectonic boundary the diversion of river courses along the mbt and around anticlines in the sub himalayas has probably been caused by aggradation near the rosion deposition boundary upstream of uplifts in the mahabharat range and sub himalayas a parallel is drawn between the himalayas and new guinea based on the hypothesis that continent arc collision of the type occurring in northern australia preceded continent continent collision in the himalayas the present sedimentary tectonic phase in new guinea resembles the subathu paleocene eocene phase in the himalayas incipient counterparts of the major himalayan structures including the mct and the mbt are recognized in new guinea the drainage patterns in the himalayas and in new guinea bear a similar relation to major structures this suggests that 1 the tectonic evolution of the himalayas has been rather uniform since early stages of collision and 2 the himalayan drainage was also formed at these early stages and is therefore antecedent to the rise of the high himalayas

diagnostic characteristics and paleodynamics of supraglacial rock avalanches innerdalen western norway abstract misinterpretation of rock avalanche deposits in mountain environments is not uncommon because of the complex interactions between rock avalanches and glaciers this paper for the first time presents a detailed description of suspicious rock boulder deposits which are remnants of a rock avalanche onto a late pleistocene glacier the boulder deposits cover around 1 1 km 2 and are distributed over an area of around 7 5 km 2 and a variety of landforms three closely nested distinct terminal moraines 0 45 km 2 and dislocated terminal moraines 0 34 km 2 entirely built up of large boulders lateral moraines that decrease in elevation over a short distance and connect to the terminal moraines small patches 0 02 km 2 of boulders that occur in islands on a peat dominated valley floor and large patches of boulder fields 0 25 km 2 in size hanging 350 m above the valley floor the latter are disconnected from any potential source area 10 be cosmogenic nuclide ages of the three terminal moraines give an indistinguishable late pleistocene age of 13 6 1 4 ka whereas the largest boulder field that is located on the opposite side of the valley from the failed mountain yields a 10 be age of 14 1 0 4 ka which is slightly older but indistinguishable from the moraine deposits within uncertainty margins all boulder deposits add up to a volume of 31 10 6 m 3 the interpretation of a single rock avalanche source for those landforms is further confirmed by numerical runout modeling using dan3d a failure of the entire volume from skarfjellet mountain would result in a runout pattern that is identical to that of the distributed boulder fields when considering that the valley was filled with a glacier around 350 m thick the rock avalanche would not reach the position of the terminal moraines however a glacial re advance could have transported the boulders to that position the late pleistocene rock avalanche was followed by a holocene rock avalanche with a volume of 23 10 6 m 3 and a typical lobate deposit damming the innerdalen valley and creating a lake 10 be ages indicate that this event occurred 7 97 0 94 ka ago structural measurements performed on high resolution lidar scans show a strongly jointed source rock with three joint sets with dip dip direction 81 034 86 331 and 77 354 and a foliation with 22 003 the kinematic of the failures can thus be a combination of small scale wedge failures and planar sliding on shallow dipping foliation our detailed description can enable a better identification and interpretation of similar deposits in other mountain areas

rock avalanches that travel onto glaciers and related developments karakoram himalaya inner asia abstract catastrophic rock slope failures in rugged terrain commonly generate rock avalanches when these occur in glacier basins the extent of landslide run out and its emplacement geometry are affected by movement over ice substantial modifications of glacier activity and sedimentation can follow ice activity leads to rapid modification transport and dispersal of landslide debris the nature of these interactions is described from observations over 20 years at bualtar glacier in the karakoram in august 1986 rock avalanches descended onto the ablation zone of the glacier their moisture content and patterns of deposition were affected by travel over ice glacier movement increased sharply at and below the rock avalanche deposits and within a few months the glacier surged a second surge occurred 2 years later major slope failures and debris flows were triggered beyond the ice margins and ponded melt water led to small outburst floods by 2005 the landslide material had been transported some 9 km about one third of this distance in the surges eventually it was fully reworked to become less readily distinguishable from other heavy supraglacial debris a large area of thickened ice persisted where the debris reduced ablation a positive impact on mass balance equivalent to a 20 increase in annual accumulation however it occurred as a moving segment of the ablation zone in 10 years it had in effect replaced the mass transferred in the surges data for the mid 1980s indicate the rock avalanches exceeded pre existing supraglacial debris by roughly five times and over a 30 year period will equal almost 500 years of normal supraglacial transport to the glacier margins other impacts of the episode suggest a doubling of this contribution to denudation similar developments were observed at three other glaciers where recent rock avalanches occurred and at twenty one prehistoric rock avalanches newly identified as having spread over glaciers it seems inadequate to treat such events only as singular extremes or the landslide and glacial processes separately here they are interpreted as contributing to disturbance regime landscapes whose history reflects episodic and regionally specific responses to strong interference among different earth surface processes they generate polygenetic deposits and landforms that are morphologically complex individual episodes involve decades to millennia their numbers and repetition can over ride or redirect geotectonic and climatic conditions it is suggested they are major but hitherto misread or neglected elements of landform evolution in the karakoram and perhaps in other high mountains

hummocky debris landforms in the chapursan valley karakoram range pakistan a glacio geomorphological investigation this paper contributes to the discussion on the development of hummocky debris landforms by gradual versus catastrophic processes in high mountain areas it focuses on the upper chapursan valley karakoram range pakistan in which the valley floor and adjacent sediment cones are covered with an outstanding hummocky debris landscape over a length of about 10 km and a width of up to 1 km with individual hummocks reaching about 10 m in height these landforms overlap with the zone of permanent settlement according to local legends and reports of early travellers in this region one of the largest settlement concentrations formerly occurred in the upper chapursan valley and was destroyed by a natural disaster in order to study the formation of the debris landforms in more detail geomorphological field investigations sedimentological studies a comparison of satellite images an analysis of historical data and interviews with the local inhabitants have been carried out the results show that complex geomorphological processes consisting of a glacier advance and followed by glacier lake outbursts and ice avalanches have contributed to the formation of the hummocky debris landforms the kit ke jerav and yishkuk glaciers seem to have experienced extraordinary fluctuations in historical and recent times

rock and soil avalanches theory and simulation 1 we present a 2 d contact dynamics discrete element model for simulating initiation and motion of rock avalanches integrating hillslope geometry mohr coulomb rock behavior pore pressure before avalanche triggering and avalanche trigger avalanche motion is modeled as a dense granular flow of dry frictional and cohesive particles on the basis of granular physics and shear experiments we review some of the theories for the unexpectedly long runout of rock avalanches different causes are evoked according to the strength strong or weak of the slip surface relative to the bulk mechanical fluidization and acoustic fluidization theories state that agitation of rock particles reduces frictional strength increasing runout conversely granular mechanics suggests that as shear strain rate increases granular material becomes more agitated more dissipative and more resistant another theory states that dynamic fragmentation of clasts creates an isotropic pressure that drives longer runout in contrast granular mechanics suggests that fragmentation may induce fluidization and strengthening of the granular material while particle size reduction among others induces weakening of the granular flow and enhances long runout runout is also enhanced for column like rock masses collapsing from steep hillslopes long runout may also be linked to thermal weakening mechanisms at the slip surface e g thermal pressurization and shear melting which may lower drastically the shear strength the model is illustrated with a hypothetical example of a rain triggered avalanche mobilizing shallowly dipping layers several phases are identified including slope failure avalanche triggering resulting from slip weakening and avalanche motion in which rocks are folded and sheared

glacial advance and stagnation caused by rock avalanches abstract new model results show that a glacier advance caused by deposition of a rock avalanche on the ice will be followed by stagnation of the advanced ice lobe producing distributed hummocky deposits quite different from the single moraine ridges typically dated in paleoclimatic reconstructions we obtain these results using a numerical flow line glacier model with superimposed rock debris in particular our results imply that the single moraine ridge known as the waiho loop of the franz josef glacier new zealand is not the result of an advance triggered by a rock avalanche else there would be a widespread hummocky glacial stagnation deposit associated with it

debris flows as agents of morphological heterogeneity at low order confluences olympic mountains washington effects of tributary junctions on longitudinal patterns of riverine heterogeneity are relevant to both fluvial geomorphology and riverine ecology we surveyed 10 km of small to moderate sized mountain channels in the olympic peninsula washington to investigate how low order confluences prone to debris flow deposition directly and indirectly influenced channel and valley morphology in the olympic mountains debris flows scour sediment and organic material from steep first and second order channels and create deposits debris fans at tributary junctions in higher order streams in lower energy depositional environments there were statistically significant relationships among debris fans at low order confluences and gravel substrate wide channels and numbers of logs and large pools effects of debris fans on channel morphology extended upstream and downstream of fan perimeters indicating the importance of indirect offsite effects of debris flows consequently certain aspects of channel morphology e g pool density substrate texture and channel widths were nonuniformly distributed reflecting the role of network topology and disturbance history on the spatial scale of morphological heterogeneity moreover heterogeneity of channel morphology increased in proximity to low order confluences prone to debris flows in contrast confluence effects in higher energy depositional environments were limited our field data and information from seven other studies indicate how variation in debris flow volume and composition stream energy and valley width at the point of deposition influence the relationship between low order confluences and channel morphology

understanding reservoir heterogeneity through water saturation prediction via neural network a case study from offshore nile delta in complex geologic settings with a great degree of heterogeneity in reservoir properties such as submarine channel complexes as in the nile delta province we face the challenge of characterizing the reservoir based on availability of different seismic attributes amplitude variation with offset avo analysis and prestack inversion techniques show impressive results in delineating the gas bearing reservoirs especially in clastic systems however a shortage of available wells and or seismic data leads to a challenge in applying avo and any prestack seismic inversion approaches in addition quantitative prediction of water saturation sw from seismic is ambiguous because of its independent nonlinear relationship with conventional seismic attributes and inversion products water saturation prediction away from the well is essential in order to characterize the reservoirs effectively therefore probabilistic neural network pnn analysis has been implemented to predict sw 3d volume using full stack se

gradual carbonate to clastic transition and provenance of quartz along the nw trento plateau southern alps italy abstract over the drowned site of the nw trento carbonate platform a gradual transition from early cretaceous pelagic carbonate to more siliciclastic sedimentation during the early tertiary is denoted by mineralogical and geochemical trends decreasing oxygen isotope ratios of quartz in the matrix from 34 33 to 18 47 smow suggest a mainly biogenic origin for the silica with insignificant terrigenous quartz input during the early cretaceous and only minor introduction of terrestrial quartz during the late cretaceous and early tertiary the insignificance of terrigenous input during the late cretaceous and early tertiary is consistent with existing depositional models that involve bypassing of the nw trento plateau margin the bulk of the terrigenous deposition being funnelled into the adjacent lombardian flysch basin bernoulli and winkler 1990 during the eoalpine tectonic phase doglioni and bosellini 1987

multiple origins of large hummock deposits in alai valley northern pamir implications for palaeoclimate reconstructions abstract this paper interprets the origin of several of the largest hummocky landform assemblages in the alai valley northern pamir a formerly glaciated intermontane depression the vast hummocky deposits in the koman suu and achik tash river catchments are found to be of two contrasting modes of formation glacial hummocks deposited during koman and lenin glaciers withdraw and avalanche hummocks produced during catastrophic koman and lenin rock avalanches the origins of the deposits we assessed through remote and field based geomorphological mapping as well as sedimentological investigations which included clast analysis and the identification of micro scale agglomerates indicative of rock avalanche emplacement both the koman and lenin rock avalanches were large catastrophic events with run outs of 34 and 24 km respectively and a volume over 1 109 m3 each that occurred subsequent to glacier withdrawal from the area the complex conditions on the moment of the rock avalanche emplacement promoted unusual deposits geomorphology and extensive run outs the landslide landforms formed over the pre existing glacial hummocks and fluvial deposits and are geomorphologically and sedimentologically distinct from the larger glacial hummocks the reconstruction of this sequence of events has implications for how hummock dating should be interpreted this research illustrates large scale catastrophic landsliding in the glacial environment and adds to the ongoing debate about the misidentification of rock avalanche deposits as of glacial origin and their relevance to palaeoclimatological and palaeoseismological reconstructions

catastrophic rock avalanches in a glaciated valley of the high atlas morocco 10be exposure ages reveal a 4 5 ka seismic event surface modification processes leading to large debris accumulations in high relief mountain areas are important for understanding landscape evolution especially in some of earth s most active orogens the arroumd rock avalanche at the foot of the nw face of mount aksoual 3912 m above sea level masl in the jebel toubkal area of the high atlas morocco represents one of the largest mass movement landforms in north africa the age and origin of this extensive feature have been contested for over a century late pleistocene moraines are also present in the same valley adjacent to the avalanche debris the mean of six 10 be cosmogenic exposure ages shows that a series of catastrophic rock slope failures occurred at 4 5 0 5 ka while a set of eight exposure ages from two of the three mapped moraines has a far larger spread from 1 5 to 7 5 ka this suggests that the avalanche events were effective agents in modifying the true surface exposure age of the pleistocene moraines in the arroumd valley this has resulted in similar mean 10 be apparent exposure ages for the preexisting late pleistocene moraine surfaces and holocene catastrophic rock slope failures similar rock avalanche deposits are present in other glaciated valleys in the high atlas we conclude that the trigger for collapse was seismic activity related to proximity of the major tizi n test fault these findings have important implications for interpreting and dating glacial landforms in tectonically active settings

debris thickness patterns on debris covered glaciers abstract many debris covered glaciers have broadly similar debris thickness patterns surface debris thickens and tends to transition from convex to concave up down glacier we explain this pattern using theory analytical and numerical models paired with empirical observations down glacier debris thickening results from the conveyor belt like nature of the glacier surface in the ablation zone debris can typically only be added but not removed and from the inevitable decline in ice surface velocity toward the terminus down glacier thickening of debris leads to the reduction of sub debris melt and debris emergence toward the terminus convex up debris thickness patterns occur near the up glacier end of debris covers where debris emergence dominates ablation controlled concave up debris thickness patterns occur toward glacier termini where declining surface velocities dominate velocity controlled a convex concave debris thickness profile inevitably results from the transition between ablation control and velocity control down glacier debris thickness patterns deviating from this longitudinal shape are most likely caused by changes in hillslope debris supply through time by establishing this expected debris thickness pattern the effects of climate change on debris cover can be better identified

the formation and impact of landslide dams state of the art abstract the blocking of river courses by mass movements is very common in mountainous areas with deep and narrow valleys landslide dams may pose serious threats to people and their livelihoods downstream in the case of abrupt dam failure since the publication of benchmark reviews of costa and schuster 1988 and korup 2002 there is a growing number of studies focusing on the formation stability and short term impacts of landslide dams this review combines the insights of all these studies builds on current concepts of landslide dams and suggests ways to unify terminologies and classifications we furthermore present a new worldwide database compiled from literature data it contains 410 landslide dams 1 million m3 in volume that were formed since 1900 since these have the most complete data entries these data show that dam longevity is among other factors correlated with the type of landslide forming the dam those formed by rock debris avalanches and rockslides have longest lifespans however the influence of landslide type or material on dam longevity decreases with time after dam formation to ensure consistency in the next database generation we suggest guidelines for data collection to provide a solid basis for evaluating dam stability and governing factors a preliminary classification matrix for landslide dam stability that combines topographic setting and the internal structure of the dam body is another outcome of our review furthermore an evaluation of the various geomorphic stability indices proposed in the literature regarding their suitability and limitations in assessing dam formation and stability shows that they predict the probability of dam formation reasonably well but that their application to longevity estimates requires further assessment the geomorphic impacts of landslide dams in the short medium and long term are summarized and illustrated with key examples finally for a better understanding of the factors controlling dam stability we recommend to 1 include dam composition and sedimentary structures in future case studies 2 maintain and update the worldwide database for sound statistical analyses 3 refine landslide dam stability indices and test them for different landslide types and 4 study hazard cascades related to multiple dams in one watershed for long term landscape evolution studies we suggest to 5 quantify terrestrial sediment flux related to landslide dams 6 detect ancient landslide dams in river profiles and 7 further exploit the sediment archives in former impoundment areas

petrologic and structural controls on geomorphology of prehistoric tsergo ri slope failure langtang himal nepal high relief h up to 2600 m and spatial orientation of discontinuities such as leucogranitic intrusions mylonitic and pseudotachylitic horizons and related ore structures were the preparatory causal factors for the giant prehistoric tsergo ri landslide high himalayan crystalline langtang himal nepal other controlling factors include overthrusting detachment faulting and paleoseismics related to the main central thrust mct and southern tibet detachment system stds neotectonically generated structures and predesigned form of the scarp broken crest and the direction of movement towards the wsw coherently displacement of several 109 m3 materials caused frictional fusion landslide dynamics and specific morphologic conditions created four different types of sliding surfaces in chronological sequence i primary at the basement ii secondary parallel or subparallel to i iii tertiary vertical to i and ii and iv quarternary sliding surfaces local variety of iii note ordinal numeric terms are not in time stratigraphic sense these planes represented the main discontinuities conducting different syn event stresses in the sliding mass and for further landslide dynamics spatial difference and widespread distribution of sliding planes and sets of discontinuities all over the landslide area caused different classes of rock quality which subsequently determined specific erosional processes within the landslide accumulation area the subsequent glacial and fluvial erosional processes were controlled by the correlating preexisting lithotectonic patterns the hyalomylonitic and or breccious sliding planes and the recent morphologic features or shapes of tsergo ri i the se part is gradationally brecciated to the top and includes tsergo ri itself the residual mass of the bulk has been eroded almost isometrically as far as the primary sliding plane crops out along the intact gneissic basement differences in rock quality along a horizon of secondary sliding planes indicate a steplike break in the relief after the last main glaciation ii the earlier halted nw part still preserved micromountainous shape of compact sliding blocks phushung i and ii kyimoshung separated by landslide dynamic triggered faults tertiary and quarternary sliding planes primary and secondary sliding planes almost covered by holocene sediments produced an insignificant morphology iii the highest brecciated strike slip fault generated during collision with the obstacle of pangshungtramo peak in the southwest is the deeply eroded dranglung chu valley which has been kept morphologically active in a major way until recent times iv except for the collision obstacle of pangshungtramo peak with recent semi active erosion and a small secondary rockslide block of tsangbu north of it all surrounding parts show typical features of high altitude erosion

quaternary moraines vs catastrophic rock avalanches in the karakoram himalaya northern pakistan a history and conception of glacial events for the central karakoram himalaya proposed some 80 years ago by giotto dainelli are largely accepted today however certain deposits identified as terminal moraine complexes marking glacial episodes were actually emplaced by rock avalanches in the skardu and shigar intermontane basins of baltistan at least 15 rock avalanche events were previously mapped as moraine or till criteria used for distinguishing these catastrophic landslide deposits emphasize homogeneous lithology of rubble and matrix clast shape facies characteristics the large scale unity of emplacement and morphological relations to valley topography the deposits of three events at katzarah satpura and the north end of shigar valley have been reconstructed in detail thick supraglacial debris does not result in similar deposits extensive valley fills river terraces large sediment fans and lacustrine sediments formerly attributed to late glacial conditions are reinterpreted as postglacial events involving rock avalanches that interrupted fluvial development existing reconstructions of glaciations are left in doubt especially late glacial events in the central karakoram as are the roles assigned to karakoram main indus valley and western himalayan ice

characteristics of surge type glaciers glaciers can be divided into two classes according to their flow behavior normal relatively steady annually averaged flow rate and surge type pronounced cyclic flow variations having a typical periodicity of 10 100 years we have examined the population statistics of 2356 glaciers in the st elias mountains yukon territory canada and estimate that 151 6 4 of these glaciers are surge type to explore how various glacier attributes are associated with surging we compare the probability of surging associated with various subsets of the complete population to appropriate reference values in this way potential influences on surge tendency can be examined for the 55 drainage basins analyzed there is a pronounced spatial variation in the concentration of surge type glaciers but no obvious environmental control can be evinced within the study area the greatest concentration lies in the northern st elias mountains a region of high topographic elevation that is experiencing rapid tectonic uplift analysis of the influence of length on surge tendency reveals that long glaciers have a significantly greater probability of being surge type than short glaciers the surge probability increases monotonically from 0 61 for very short glaciers 0 1 km to 65 1 for long glaciers 10 75 km this result suggests that ice sheets and ice caps or at least portions of them should have a high probability of surging tributary glaciers have a greater tendency to surge than trunk glaciers presumably because they may themselves be surge type and may additionally participate in surges of the trunk glacier the nonrandom geographical distribution of surge type glaciers is not simply a consequence of the variation from basin to basin of the glacier length distribution surge type glaciers tend to have a higher overall elevation than normal glaciers the elevation of the highest point of the accumulation zone the elevation of the snow line and the elevation of the lowest point of the ablation zone on average exceed the corresponding elevations for normal glaciers there is no significant difference between the overall slopes of surge type and normal glaciers although there is a tendency for surge type glaciers to have greater slope in the accumulation zone and lesser slope in the ablation zone than normal glaciers although the prevalent flow direction for glaciers in the yukon data set is to the north surge type glaciers tend to flow to the east and southeast this orientation influence is probably explained by the fact that many of the longest glaciers also flow to the east and southeast

a mass movement origin for cirques the glacial process of cirque initiation whereby small initial hillslope hollows grow by nivation until snow can form glacier ice and ice motion then enlarges the hollow to a fully developed cirque appears to have difficulty explaining the creation of large cirques in the time available during quaternary glaciations at the rates at which glaciers are reported to erode rock and in rapidly uplifting mountain ranges it also has difficulty explaining the striking proliferation of cirques in fiordland south island new zealand an area of harder rock and less glaciation than the nearby cirque poor area of south westland here we show that cirques can be initiated as large deep seated often coseismic rock slope failure source area depressions in which snow may accumulate to form cirque glaciers which can then remove detritus from smooth and enlarge the cirque we present an example of a classically shaped cirque that has never held a glacier we show that many similarities between the locations sizes and shapes of rock slope failure source area depressions and cirques are understandable on this basis as is the occurrence of cirques in presently aseismic intraplate locations and their relative paucity in actively uplifting ranges the extent to which cirques may be of mass movement origin has implications for their value as palaeoclimatic indicators copyright 2006 john wiley sons ltd

subaqueous rock avalanche deposits exposed by post glacial isostatic rebound innfjorddalen western norway abstract this paper presents a detailed description of deposits and landforms of multiple rock avalanches in western norway one of which fell onto water saturated sediments in innfjorddalen below the former water level deposits of the latter are now exposed on the valley floor due to post glacial isostatic rebound at least three rock avalanches from the same source at grafonnfjellet mountain have occurred during late glacial and post glacial time and their deposits are distributed over an area of 1 44 km 2 in the valley these rock avalanches have volumes of 15 1 10 6 m 3 5 4 10 6 m 3 and 0 3 10 6 m 3 and yielded cosmogenic radionuclide 10 be ages of 14 3 1 4 ka 8 79 0 94 ka and 1 028 0 380 ka respectively the youngest event dates within uncertainty limits to a historic rock avalanche in the year 1611 12 ce the rock avalanches formed a stratified succession of deposits the rock avalanche deposits 1 38 m 2 have lobate forms have frontal rims and parallel ridges extend across the valley floor and up the opposite slope and form dams on the valley floor isolated hills comprised of rock boulders 0 61 km 2 interpreted to be toma hills are disconnected from the main rock avalanche deposits by a 520 m wide zone of deformed valley fill sediments trenches and a ground penetrating radar survey of these deposits indicate large scale deformation or liquefaction numerical runout modeling of the rock avalanches with the code dan3d supports the interpretation of their landforms and sources and highlights their runout behavior

deglaciation and landscape history around annapurna nepal based on 10be surface exposure dating abstract the high himalaya is a key area for tectonic geomorphological and climate studies because of its extreme relief and location at the transition zone between areas with abundant monsoonal precipitation and the arid semiarid tibetan plateau we present 10be surface exposure ages on 22 boulders from the annapurna area in nepal the ages improve understanding of the late quaternary landscape history and the geomorphological processes operating in this part of the himalaya although our study is reconnaissance in nature it highlights the importance of catastrophic events such as landslides and debris flows for denudation of high mountains holocene exposure ages for the dhampu chooya landslide 4 1 0 6 ka and for 600 m of alluviation in kali gandaki valley 2 1 0 6 ka for example indicate the frequent occurrence and extent of catastrophic events and their implications for natural hazards we also offer an explanation for the differences in late quaternary glacial chronologies at closely spaced study sites in the nepal himalaya topographically controlled and spatially variable precipitation in the himalaya determines the sensitivity of glaciers to changes in temperature and precipitation accordingly some glaciers advanced in phase with northern hemisphere ice sheets whereas others reached their maximum extent at times of increased monsoonal precipitation during marine isotope stage 3 and the early holocene

the sedimentology and geomorphology of rock avalanche deposits on glaciers this article describes and compares the deposits of four large landslides on two glaciers in alaska using field mapping and remote sensing digital image analysis is used to compare the sedimentological characteristics of nearly 200 000 individual surface blocks deposited by three landslides at black rapids glacier in 2002 the debris sheets of one of the three landslides on black rapids glacier and a landslide emplaced on sherman glacier in 1964 are also investigated the three landslides on black rapids glacier have undergone little post depositional modification by glacier flow whereas the sherman glacier landslide has been transported supraglacially up to ca 1k m over the past 46 years the three debris sheets on black rapids glacier have coarse blocky rims at their distal edges and all four debris sheets have longitudinal flowbands characterized by differences in texture and produced by shearing within the moving debris elongated blocks are parallel to flow except at the perimeter of the debris sheets where they are aligned more perpendicular to flow blocks on the sherman glacier debris sheet have been reoriented by glacier flow the matrix shows no systematic differences with depth or distance from the source however it appears to become coarser over a time scale of decades due to weathering

formation of the waiho loop terminal moraine new zealand we present an analysis of the formation and evolution of the waiho loop terminal moraine recent work has shown that the loop comprises mainly rock avalanche material and suggested its formation was associated with a rock avalanche driven glacier advance new evidence from shallow seismic studies between the range front and the loop suggests i that the presence of a basal trough critically influences glacier behaviour and moraine formation and ii that the volume of the waiho loop is significantly greater than previously thought a one dimensional dynamic ice flow model is used to test two rock avalanche based scenarios for the formation of the loop first that a rock avalanche caused a significant advance of the glacier terminus from a location within the confined mountain valley to the loop and second that the rock avalanche occurred while the glacier was retreating with its terminus close to the position of the loop it is shown that this terminal moraine was not the result of a glacier advance

the dusty creek landslide on mount cayley british columbia a large ca 5 106 m3 landslide occurred on the west flank of mount cayley in the southern coast mountains of british columbia in 1963 failure commenced when a large block of poorly consolidated tuff breccia and columnar jointed dacite was detached from the subvolcanic basement and slid into the valley of dusty creek a small tributary of turbid creek as the detached block accelerated it quickly fragmented into an aggregate consisting of angular clasts up to several metres across partially supported by a matrix of fine comminuted rock material the landslide debris moved about 1 km down dusty creek as a wedge shaped mass up to 70 m thick banking up on turns and attaining a maximum velocity of 15 20 m s the debris mass thinned as it spread across the broader flatter valley of turbid creek and was deposited as an irregular blanket with a maximum thickness of 65 m along a 1 km length of this valley as a result of the landslide turbid and dusty creeks were blocked and lakes formed behind the deb

catastrophic landslides glacier behaviour and moraine formation a view from an active plate margin the influence of large bedrock landslides rock avalanches on the behaviour of glaciers is incompletely recognised here we present an example from an active tectonic margin in south island new zealand where large earthquakes leave a significant imprint on glacial records we demonstrate that terminal moraines on the western side of the southern alps record both ordinary i e climate driven and landslide initiated glacial advances following consideration of the processes involved in rock avalanche initiated moraine construction we suggest ways of determining the nature of the advance that built the terminal moraine the implications of these observations are important in breaking the conventional linkage of individual terminal moraines with climate forcing

catastrophic landslides and their effects on the upper indus streams karakoram himalaya northern pakistan abstract the paper examines the nature and geomorphic influences of deposits from rock avalanches that obstruct rivers most of the 115 rockslide rock avalanche events identified in the karakoram himalaya straddled one or more stream valleys at least 73 of these landslides formerly dammed the indus or its tributaries upstream of the barriers remnants exist of once very extensive lacustrine deposits the stability and long term survival of dams from large rock avalanches is addressed and the reasons for the gradual or phased rather than catastrophic and sudden breaching case histories emphasise the erosional and depositional forms associated with the barriers they are reconstructed in terms of the emplacement and properties of the deposits from rock avalanches and the response of the river to interruption by them these barriers have exerted a substantial control over stream response and development for most of the holocene at least today they are associated with distinctive features of channel form and thalweg river terrace systems intermontane sediment sinks and sources and local erosional forms in bedrock more broadly the landslide barriers have created a naturally fragmented river system deposition and erosion in the lower few tens or hundreds of meters of the upper indus stream valleys have been dominated by epicycles of aggradation trenching and downcutting that mainly reflect the scale timing and history of each barrier the landforms involved are only indirectly related to the late glacial and paraglacial conditions that have hitherto been regarded as the main explanation

recent spatial and temporal variations in debris cover on patagonian glaciers abstract supraglacial debris cover is an important component of glacier mass balance especially in areas characterised by widespread glacier recession mapping of the spatial and temporal changes in debris cover on the surface of the receding outlet glaciers of the temperate north patagonian icefield npi in southern south america between 1987 and 2015 shows that the total amount of debris cover has increased over time from 168 km2 in 1987 to 307 km2 in 2015 the number of debris covered glaciers increased from 24 in 1987 to 31 in 2001 and 32 out of 43 studied glaciers in 2015 the proportion of debris covered area has also increased from 4 1 in 1987 to 7 9 in 2015 with the largest proportional increases occurring east of the ice divide where 15 2 of the glacier ice is now debris covered over this time the total area of the npi decreased from 4133 to 3887 km2 the area occupied by proglacial and ice proximal lakes also increased from 112 to 198 km2 between 1987 and 2015 the terminal environment of many of the outlet glaciers of the npi changed from land terminating to lake calving and these glaciers are now receding into terminal lakes the change in the area of debris covered ice is influenced by the loss of ice at debris covered termini and by an increase in debris cover at higher elevations the glaciers of the npi remain highly dynamic as they recede and are therefore behaving very differently to high elevation glaciers such as those of the himalaya where debris cover leads to glacier stagnation at the termini

modeling and simulation of glacier avalanche a case study of gayari sector glaciers hazards assessment glacier avalanches are natural hazards that could damage infrastructures and threaten lives in high altitude mountainous terrains on april 7 2012 a massive ice avalanche struck a pakistani base at gayari sector saltoro valley and buried killed 148 soldiers and civilians keeping in view the catastrophe a study was designed with the objectives to 1 model and simulate the gayari sector glacier avalanche incident in terms of height extent velocity pressure and momentum 2 generate hazard risk assessment of possible other glacier avalanches in the saltoro valley through modeling and simulation and 3 suitability analysis of current camp sites and recommendation of new safe camps sites locations in the saltoro valley to simulate the gayari sector glacier event and other glacier possible avalanches a physical process based rapid mass movements ramms was used the ramms has two main components i e voellmy salm vs model and random kinetic energy which deals with variables such as avalanche height and the mean avalanche velocity during the course of simulation the suitability analysis of current camp sites were achieved using weighted overlay analysis with different constraints in arcgis spatial analyst the ramms model simulation of the gayari avalanche event predicted a maximum velocity of 74 ms 1 generating a pressure of 5074 kpa and attaining a height of 45 m whereas the predicted debris volume on the ground was 3 8145 million m 3 a good agreement was found between actual debris height and extent as compared with the ramms model output the ramms model simulated all the potential tributary glacier avalanches of saltoro valley very well the weighted overlay analyses in arcgis spatial analyst revealed that the existing camp sites are safe and were not threatened by the glacier avalanche hazard however it was recommended that the gayari camp should not be constructed at the same location and should be relocated to the proposed safe camp sites identified in this research study the proposed methodology developed in the current study could be applied in the siachen conflict zone for avalanche hazard risk analysis of all the camp sites located in the valley

a review of topographic controls on moraine distribution ice marginal moraines are often used to reconstruct the dimensions of former ice masses which are then used as proxies for palaeoclimate this approach relies on the assumption that the distribution of moraines in the modern landscape is an accurate reflection of former ice margin positions during climatically controlled periods of ice margin stability however the validity of this assumption is open to question as a number of additional nonclimatic factors are known to influence moraine distribution this review considers the role played by topography in this process with specific focus on moraine formation preservation and ease of identification topoclimatic controls are not considered published literature indicates that the importance of topography in regulating moraine distribution varies spatially temporally and as a function of the ice mass type responsible for moraine deposition in particular in the case of ice sheets and ice caps 1000 km2 one potentially important topographic control on where in a landscape moraines are deposited is erosional feedback whereby subglacial erosion causes ice masses to become less extensive over successive glacial cycles for the marine terminating outlets of such ice masses fjord geometry also exerts a strong control on where moraines are deposited promoting their deposition in proximity to valley narrowings bends bifurcations where basins are shallow and or in the vicinity of topographic bumps moraines formed at the margins of ice sheets and ice caps are likely to be large and readily identifiable in the modern landscape in the case of icefields and valley glaciers 10 1000 km2 erosional feedback may well play some role in regulating where moraines are deposited but other factors including variations in accumulation area topography and the propensity for moraines to form at topographic pinning points are also likely to be important this is particularly relevant where land terminating glaciers extend into piedmont zones unconfined plains adjacent to mountain ranges where large and readily identifiable moraines can be deposited in the case of cirque glaciers 10 km2 erosional feedback is less important but factors such as topographic controls on the accumulation of redistributed snow and ice and the availability of surface debris regulate glacier dimensions and thereby determine where moraines are deposited in such cases moraines are likely to be small and particularly susceptible to post depositional modification sometimes making them difficult to identify in the modern landscape based on this review we suggest that despite often being difficult to identify quantify and mitigate topographic controls on moraine distribution should be explicitly considered when reconstructing the dimensions of palaeoglaciers and that moraines should be judiciously chosen before being used as indirect proxies for palaeoclimate i e palaeoclimatic inferences should only be drawn from moraines when topographic controls on moraine distribution are considered insignificant

catastrophic landslide deposits in the karakoram himalaya in july 1986 three catastrophic landslides deposited about 20 x 106 cubic meters of debris on bualtar glacier in the karakoram himalaya a sudden acceleration and superficial breakup of the glacier provided an opportunity to examine the fresh deposits in depth beneath a surface layer of large boulders finer materials mainly sand and silt made up half of the total volume the fine materials were formed during the rock avalanche from mostly intact massive rock of the source zone velocity estimates suggest that this disaggregation occurred in less than 2 minutes coarse materials remained in bands of uniform lithology but the fine materials had diffused throughout the landslides a small amount of carbonate appears to have been calcined by frictional heating presumably at the base of the initial sliding masses these observations are relevant to understanding the mechanisms of catastrophic landslides other nearby rock avalanche deposits indicate that landslides are an important geomorphic process in the area and that they pose a continuing risk to human activity