remote sensing estimates of glacier mass balances in the himachal pradesh western himalaya india abstract although they correspond to an important fraction of the total area of mountain glaciers 33 000 km2 out of 546 000 km2 himalayan glaciers and their mass balance are poorly sampled for example between 1977 and 1999 the average area surveyed each year on the field was 6 8 km2 only no direct mass balance measurement is available after 1999 to contribute to fill this gap we use remote sensing data to monitor glacier elevation changes and mass balances in the spiti lahaul region 32 2 n 77 6 e himachal pradesh western himalaya india our measurements are obtained by comparing a 2004 digital elevation model dem to the 2000 srtm shuttle radar topographic mission topography the 2004 dem is derived from two spot5 satellite optical images without any ground control points this is achieved thanks to the good on board geolocation of spot5 scenes and using srtm elevations as a reference on the ice free zones before comparison on glaciers the two dems are analyzed on the stable areas surrounding the glaciers where no elevation change is expected two different biases are detected a long wavelength bias affects the spot5 dem and is correlated to an anomaly in the roll of the spot5 satellite a bias is also observed as a function of altitude and is attributed to the srtm dataset both biases are modeled and removed to permit unbiased comparison of the two dem on the 915 km2 ice covered area digitized from an aster image on most glaciers a clear thinning is measured at low elevations even on debris covered tongues between 1999 and 2004 we obtain an overall specific mass balance of 0 7 to 0 85 m a water equivalent depending on the density we use for the lost or gained material in the accumulation zone this rate of ice loss is twice higher than the long term 1977 to 1999 mass balance record for himalaya indicating an increase in the pace of glacier wastage to assess whether these ice losses are size dependant all glaciers were classified into three samples according to their areal extent all three samples show ice loss the loss being higher for glaciers larger than 30 km2 in the case of the benchmark chhota shigri glacier a good agreement is found between our satellite observations and the mass balances measured on the field during hydrological years 2002 2003 and 2003 2004 future studies using a similar methodology could determine whether similar ice losses have occurred in other parts of the himalaya and may allow evaluation of the contribution of this mountain range to ongoing sea level rise

recent progress in snow and ice research a review of snow and ice research in 1987 1990 is presented focusing on the effects of layers in seasonal snow covers ice mechanics on fresh water and sea ice and remote sensig of polar ice sheets these topics provide useful examples of general needs in snow and ice research applicable to most areas such as better representation in models of detailed processes controlled laboratory experiments to quantify processes and field studies to provide the appropriate context for interpretation of processes from remote sensing

complete dynamic modeling calibration for the thurwieser rock avalanche italian central alps abstract few rock avalanches have been witnessed and no exact real time description is available the 2 5 m m 3 punta thurwieser rock avalanche september 2004 italian central alps is a unique event for which many quantitative observations have been gathered this is the first case ever of a natural rock avalanche being recorded on video and for which an almost exact value of the total time duration from initial detachment to final deposition is available the landslide travelled over 2 9 km from its source partially in a glacial environment the initial failure and the time for the complete evacuation of the source area were studied and assessed by a series of photos the mean front velocities along the path have been estimated from the video the final geometry and the characteristics of the deposit have been obtained by gps measurements aerial photos field surveys and laboratory tests a quasi 3d continuum dynamic analysis of the landslide motion has been performed assuming both a voellmy and a frictional rheology in the model dan 3d for the first time the landslide front velocities have been used for back analyses and calibration of the rheological parameters together with the final shape and thickness of the deposit and its developing extension the dynamic flow resistance parameters initially calibrated with dan were adopted and validated in dan 3d showing good consistency they are consistent with the existing database for calibrated landslides of similar type and scale flow velocities on the path segment underlain by glacial deposits up to 55 65 m s 1 are more accurately predicted by adopting a frictional rheology up to 50 55 m s 1 with zero pore pressure and a 26 friction angle than by a voellmy rheology up to 40 45 m s 1 both observations and modelling show that glacial ice plays a substantial role in increasing the rock avalanche mobility

rock avalanche geomorphological and hydrological impact on an alpine watershed abstract rock avalanches are large flow like movements of fragmented rock that can cause extensive and rapid topographic changes for which very few quantitative data are available this paper analyses the geomorphological and hydrological impact of the 3 million m 3 thurwieser rock avalanche 2004 italian central alps by using terrestrial laser scanner airborne lidar and gnss data collected from 2005 to 2014 sediment yield with respect to the normal valley regime the dynamic and mass balance of affected glaciers and the reorganization of superficial and groundwater flow networks are quantified in the middle portion of the avalanche deposit a natural sediment trap collected sediments from a new stream channel developed along the upper portion of the deposit and from a lateral drainage basin this made possible to assess the 10 year impact of the rock avalanche on the sediment yield which increased from about 120 to about 400 t km 2 a 1 the rock avalanche partially covered a glacier with a shallow debris layer that acted as a thermal insulator limiting ice ablation and producing a 10 m high scarp between the free surface of the glacier and the debris covered portion a reduction of 75 of ice ablation was observed due to thermal insulation the rock avalanche filled a tributary valley splitting the original drainage basin in two under ordinary flows seepage occurs within the avalanche deposit along the old valley axis during high flow conditions a new stream channel is activated along the middle and lower margin of the deposit which has produced a new alluvial fan on the main valley floor the fan evolution is described up to the present volume of about 2000 m 3

hydrological regimes under the conjunction of westerly and monsoon climates a case investigation in the astore basin northwestern himalaya in a changing climate river basins with limited summer precipitation but abundant snow and glacier melt water are affected severely by reductions and seasonal alterations in annual stream flows however high altitude glacio hydrological observations and investigations to address the linkage between the timing of glacier changes and river runoff fluctuations remain ambiguous particularly in the northwestern himalayan region of pakistan in this context the hydrological regime of the astore basin a sub catchment of the upper indus river basin was comprehensively investigated by employing in situ hydro meteorological observations in combination with satellite remote sensing data two thirds of the annual precipitation in the astore basin falls in winter and spring mainly deposited by westerly winds whereas summer and autumn precipitation deposited by the monsoon and local jet streams accounts for only one third some 14 of the basin area is covered by glaciers and added to the accumulated seasonal snow deposited by westerly circulations this can reach 80 85 of the basin area therefore more than 75 of the annual basin runoff depends on melt water produced by the predominant seasonal snow and glacier ablation the non parametric mann kendall trend test was applied to the whole time series of hydro meteorological data this indicated a lowering of annual and summer mean temperatures during the period 1980 1995 and slight warming during the 1996 2010 period similarly annual winter and summer precipitation and annual mean discharge increased from 1980 to 1995 but in contrast a slight decrease in annual and summer precipitation was observed during the 1996 2010 period however discharge evidence is slight making any increase in this period insignificant in addition the spearman and mann kendall correlation results depict annual stream flow fluctuations during the 1980 2010 decades in the astore river that were predominantly influenced by precipitation variations but not by any alteration in catchment temperatures and so not governed by enhanced glacier ablation and retreat the results of the analysis presented here were also substantiated by satellite remote sensing investigation which points to evidence of stable conditions in the astore basin glaciers during this period

transport of atmospheric impurities over the qinghai xizang tibetan plateau as shown by snow chemistry abstract chemical records were recovered from samples collected from snow pits over two transects s n and se nw across the qinghai xizang tibetan plateau the records show that the flux of major ions in the regions to the north of mt tanggula is on the average 6 30 times higher than that of the regions to the south and 0 6 5 times higher than regions to the southeast it appears that mt tanggula provides a barrier to continental dust transported across the plateau from the north and to marine aerosols transported from the southeast the spatial patterns of snow chemistry as well as the total suspended particle tsp distribution along the northern qinghai xizang highway demonstrate that continental dust originates mainly from the deserts to the north while monsoon sources of moisture exert greater influence on snow chemistry on the southern part of the plateau seasonal variations of the major ions were also examined in a firn core drilled at a height of 7000 m on the dasuopu glacier and in a snow pit from the meikuang glacier eastern kunlun the choice of a high altitude site at dasuopu and the sampling season before snowmelt at meikuang avoided post depositional modification processes mainly the elution effect of meltwater thus guaranteeing the reliable recovery of the distribution of impurities in different seasons the peak of the impurities appear at dasuopu during the spring and at meikuang in the winter spring coinciding with the asian dust season however the amplitude of the seasonal variations at meikuang is much higher than at dasuopu ph values at the dongkemadi glacier are greater than 6 but at the dasuopu glacier himalayas they range between 4 and 7 5 the liquid conductivity lc from dongkemadi is positively correlated with the ph while at dasuopu lc is positively correlated with ph when ph is below 6 and negatively correlated with ph when it is greater than 6 this implies that during august to september the himalayan range is a transition zone between the transportation of continental dust and marine aerosols

estimating glacier bed overdeepenings as possible sites of future lakes in the de glaciating mont blanc massif western european alps de glaciating high mountain areas result in new landscapes of bedrock and debris where permafrost can degrade persist or even newly form in cases and of new lakes in glacier bed overdeepenings gbos becoming ice free these landscapes with new lakes in close neighborhood to over steepened and perennially frozen slopes are prone to chain reaction processes e g rock ice avalanches into lakes triggering impact waves dam breach or overtopping and debris flows with potentially far reaching run out distances causing valley floors devastation the frequency magnitude and zonation of hazards are shifting requiring integrative approaches combining comprehensive information about landscape evolution and related processes to support stakeholders in their adaptation strategies in this study we intend to setup an essential baseline for such an integrative approach in the mont blanc massif mbm which is a typical high mountain range affected by de glaciation processes we first i predict and ii detect potential gbos by combining the glabtop model with a visual analysis based on morphological indications of glacier flow through over deepened bed parts we then iii determine the level of confidence concerning the resulting information and iv estimate the approximate time range under which potential lakes could form the location of the predicted gbos and the shape of glacier beds are evaluated against currently forming water bodies at retreating glacier snouts and seismic and ice penetrating radar measurements on the argentiere glacier this comparison shows that the location of predicted gbos is quite robust whereas their morphometric characteristics depth volume are highly uncertain and tend to be underestimated in total 48 80 of the predicted or detected gbos have a high level of confidence in addition to five recently formed water bodies at glacier snouts one of the high confidence gbos talefre glacier which is also the most voluminous one could form imminently during coming years if not partially or totally drained through deeply incised gorges at the rock threshold twelve other lakes could form within the first half of the century under a constant or accelerated scenario of continued glacier retreat some of them are located below high and permanently frozen rock walls prone to destabilization and high energy mass movements hinting at possible hot spots in terms of hazards in the coming decades where more detailed analysis would be required

comparative analysis of contributing parameters for rainfall triggered landslides in the lesser himalaya of nepal in the himalaya people live in widely spread settlements and suffer more from landslides than from any other type of natural disaster the intense summer monsoons are the main factor in triggering landslides however the relations between landslides and slope hydrology have not been a focal topic in himalayan landslide research this paper deals with the contributing parameters for the rainfall triggered landslides which occurred during an extreme monsoon rainfall event on 23 july 2002 in the south western hills of kathmandu valley in the lesser himalaya nepal parameters such as bedrock geology geomorphology geotechnical properties of soil and clay mineralogy are described in this paper landslide modeling was performed in seep w and slope w to understand the relationship of pore water pressure variations in soil layers and to determine the spatial variation of landslide occurrence soil characteristics low angle of internal friction of fines in soil medium range of soil permeability presence of clay minerals in soil bedrock hydrogeology and human intervention were found to be the main contributing parameters for slope failures in the region

mapping the suitability for ice core drilling of glaciers in the european alps and the asian high mountains ice cores from mid latitude mountain glaciers provide detailed information on past climate conditions and regional environmental changes which is essential for placing current climate change into a longer term perspective in this context it is important to define guidelines and create dedicated maps to identify suitable areas for future ice core drillings in this study the suitability for ice core drilling sicd of a mountain glacier is defined as the possibility of extracting an ice core with preserved stratigraphy suitable for reconstructing past climate morphometric and climatic variables related to sicd are selected through literature review and characterization of previously drilled sites a quantitative weight of evidence method is proposed to combine selected variables i e slope local relief temperature and direct solar radiation to map the potential drilling sites in mid latitude mountain glaciers the method was first developed in the european alps and then applied to the asian high mountains model performances and limitations are discussed and first indications of new potential drilling sites in the asian high mountains are provided results presented here can facilitate the selection of future drilling sites especially on unexplored asian mountain glaciers towards the understanding of climate and environmental changes

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

insights into the kinematics and dynamics of the luanshibao rock avalanche tibetan plateau china based on its complex surface landforms abstract complex topographic features on the surfaces of rock avalanche deposits have been regarded as important indicators for understanding avalanche kinematics and dynamics based on a combination of remote sensing data and in situ observations of surface landforms including toreva blocks transverse and longitudinal ridges ridges separated by conjugate troughs and hummocks a giant holocene rock avalanche on the tibetan plateau is recognized this work aims to understand the kinematics of this event in planview the tongue shaped rock avalanche exhibits a clear sequential distribution of various landforms the translation zone ii is characterised by toreva blocks originating from extension in subzone iii 1 of the accumulation zone iii compression related transverse ridges are well developed longitudinal ridges resulting from lateral velocity differences due to radial spreading are present in the front part of subzone iii 1 farther down ridges separated by conjugate troughs generated by a combination of compression and radial spreading are common in subzone iii 2 subzone iii 3 is characterised by abundant scattered hummocks with circular to oval shapes based on the distributions of these landforms this rock avalanche is proposed to have mainly experienced a motion featuring laminar flow with radial spreading in its distal and marginal parts during transport three distinct processes appear to have occurred in the avalanche mass from the proximal to the distal zones extension dominated sliding in zone ii compression dominated sliding in subzones iii 1 and iii 2 and rapid radial spreading in subzone iii 3

climatic signal of ice melt features in southern greenland the stratigraphie record of melt features in intermediate depth polar ice cores has provided valuable data on past summer climate1 3 the thermal drilling technique used in previous studies precluded extending this record beyond a few hundred years recently however a 901 m deep ice core was mechanically drilled in southern greenland the excellent core quality and improved techniques for measuring melt features have resulted in an 2 200 yr record with consistently high quality data we report here that the temporal variations in melt feature abundance expressed as annual melt per cent amp provide proxy data on summer climate that can complement other records extending back thousands of years the amp profile indicates that relatively warm summers prevailed from about ad 950 until ad 1500 culminating in the thirteenth and fourteenth centuries the periods from about 300 to 150 bc ad 350 to 550 and ad 1550 to 1800 had relatively little summer melting

testing landslide and atmospheric effects models for the formation of double layered ejecta craters on mars double layered ejecta dle craters are distinctive among the variety of crater morphologies observed on mars but the mechanism by which they form remains under debate we assess two ejecta emplacement mechanisms 1 atmospheric effects from ejecta curtain induced vortices or a base surge and 2 ballistic emplacement followed by a landslide of ejecta assisted by either surface or pore ice we conduct a morphological analysis of the ejecta facies for three dle craters which impacted into irregular pre existing topography we find that the unique topographic environments affected the formation of grooves and the inner facies and thus appear to be inconsistent with an atmospheric effects origin but are supportive of the landslide hypothesis we distinguish between the two landslide models lubrication by either surface or pore ice by assessing relationships between dle crater ejecta and morphologic features indicative of buried ice deposits including sublimation pits ring mold craters expanded secondary craters and excess ejecta craters the association of dle craters with these features suggests that surface ice was present at the time of the impacts that formed the dle craters we also compare the froude numbers of dle crater ejecta to landslides and find that the ejecta of dle craters are kinematically and frictionally similar to terrestrial landslides that overran glaciers this suggests that the grooves on dle craters may plausibly form through the same shear splitting mechanism as the landslides in summary our analysis supports the hypothesis that dle craters form through meteoroid impacts into decameters thick surface ice deposits emplaced during periods of higher obliquity followed by ejecta sliding on the ice

impurity sources of f cl no3 and so4 2 in greenland and antarctic precipitation five polar impurity sources are proposed anthropogenic no3 and so42 in recent greenland but not antarctic snow marine aerosols the dominant cl source volcanic eruptions which produce detectable but variable peaks in so42 f and or cl concentrations biogenic sulfurous gases from soil and coastal waters the dominant source for so42 in nonvolcanic strata an unidentified source of background nitrate which is more active in the northern hemisphere and which displays a summer concentration maximum solar activity and supernova events do not modulate no3 concentrations in greenland snow

longitudinal ridges in mass movement deposits prominent longitudinal features are often reported on the surfaces of mass movement deposits however the genesis and implications of these have not hitherto been considered and herein we present preliminary observations of their occurrence both in the field and in the laboratory elongated ridges are often oriented sub parallel to the flow direction and aligned radially from the source due to debris spreading they are particularly prominent in large 106m3 rock avalanches emplaced onto deformable substrates and are also found in the proximal reaches of volcanic debris avalanches flowbands which are longer and thinner expressions of longitudinal ridges are continuous along the entire flow length and are observed in rock avalanches emplaced onto glaciers in snow and some ice avalanches in pyroclastic flows and some block and ash flows in ejecta sheets in extraterrestrial landslides and in some volcanic debris avalanches other volcanic debris avalanches and the distal areas of rock avalanches often display hummocks that are aligned radially from the source we propose that these aligned hummocks are remnants of longitudinal ridges the formation of elongate ridges and their expressions as flowbands aligned hummocks or distal lobes and digits in qualitatively similar fashion in both laboratory and field environments suggests they represent an intrinsic tendency of granular flows in a wide range of situations

karakorum hindukush western himalaya assessing high altitude water resources the high mountains of central and south asia provide irrigation water for their adjacent lowlands the indus irrigation scheme depends on approximately 50 of its runoff originating from snowmelt and glacier melt from the eastern hindukush karakorum and western himalaya the atlas of pakistan indicates that these mountains gain a total annual rainfall of between 200 and 500 mm amounts that are generally derived from valley based stations and not representative for elevated zones high altitude snowfall seems to be neglected and is obviously still rather unknown estimates derived from accumulation pits runoff above 4000 m range from 1000 mm to more than 3000 mm depending on the site and time of investigation as well as on the method applied to assess the vertical spatio temporal distribution of total annual precipitation a combined approach is presented this approach links in situ measurements of snow depth and water equivalent 10 year time series derived from automatic weather stations at elevations between 1500 and 4700 m a s l the spatial distribution and period of snow coverage remotely sensed data and digital elevation models and the runoff characteristics of streams originating from snow or snow ice covered watersheds modified snowmelt runoff model including intermediate snowfall and glacier runoff based on conservative assumptions the vertically changing seasonal ratio between liquid and solid precipitation is calculated using a combined snow cover and ablation model total annual amounts of precipitation are derived for different altitudinal zones amounts of modelled and measured runoff complement the investigation horizontal gradients along the indus gilgit hunza transect indicate the varying dominance of seasonal precipitation regimes monsoonal mediterranean and continental disturbances south of nanga parbat between nanga parbat and batura wall west karakorum rainfall regime 1500 1800 mm year 1 at 5000 m and areas north of batura central asian rainfall regime 600 mm year 1 at 5000 m copyright 2005 john wiley sons ltd

lithological and seasonal control on rainfall thresholds for the possible initiation of landslides in central italy we compiled a catalogue of 442 rainfall events with landslides in the abruzzo marche and umbria regions central italy between february 2002 and august 2010 for each event we determined the duration d in hours and the cumulated total event rainfall e in mm using rainfall measurements obtained from a dense network of 150 rain gauges landslides were mapped as single points using google earth and were attributed a level of mapping accuracy p in four classes p1 1 km2 p10 10 km2 p100 100 km2 p300 300 km2 using this information we determined cumulated event rainfall rainfall duration ed thresholds which are entirely equivalent to rainfall intensity duration id thresholds and avoid unnecessary conversions to determine the ed thresholds we modified a statistical method first proposed to determine id thresholds adopting a bootstrapping statistical technique we expanded the method to determine the uncertainty associated with the parameters that define the power law threshold model and the sensitivity of the thresholds to the number of d e data points in the empirical data set we determined ed thresholds for 1 and 5 exceedance probability levels i for the entire study area and for the three individual regions in the study area abruzzo marche and umbria ii for three main lithological domains in the study area post orogenic sediments flysch deposits carbonate rocks and iii for two seasonal periods may september october april comparison of the ed thresholds indicates that the cumulated amount of rainfall necessary to trigger landslides in flysch deposits is larger than in post orogenic sediments and carbonate rocks however the ed thresholds for post orogenic sediments and carbonate rocks were statistically indistinguishable in the study area also the seasonal thresholds were statistically different for rainfall durations shorter than 12 h and longer than 100 h but were indistinguishable in the range 12 d 100 h the results obtained are directly applicable to landslide forecasting based on empirical rainfall thresholds and have implications for landslide hazard and risk assessment as well as for landslide erosion and landscape evolution studies both in the study area and in the neighboring regions

review of the status and mass changes of himalayan karakoram glaciers we present a comprehensive review of the status and changes in glacier length since the 1850s area and mass since the 1960s along the himalayan karakoram hk region and their climate change context a quantitative reliability classification of the field based mass balance series is developed glaciological mass balances agree better with remotely sensed balances when we make an objective systematic exclusion of likely flawed mass balance series the himalayan mean glaciological mass budget was similar to the global average until 2000 and likely less negative after 2000 mass wastage in the himalaya resulted in increasing debris cover the growth of glacial lakes and possibly decreasing ice velocities geodetic measurements indicate nearly balanced mass budgets for karakoram glaciers since the 1970s consistent with the unchanged extent of supraglacial debris cover himalayan glaciers seem to be sensitive to precipitation partly through the albedo feedback on the short wave radiation balance melt contributions from hk glaciers should increase until 2050 and then decrease though a wide range of present day area and volume estimates propagates large uncertainties in the future runoff this review reflects an increasing understanding of hk glaciers and highlights the remaining challenges

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

characteristics and transport mechanism of the nyixoi chongco rock avalanche on the tibetan plateau china abstract for studying rock avalanches complex surficial and internal characteristics have been regarded as important indicators for understanding avalanche transport mechanism in the present study deposits of a massive holocene rock avalanche termed the nyixoi chongco rock avalanche located on the lhasa terrane of tibetan plateau in china are investigated based on a combination of remote sensing data and in situ observations it is revealed that abundant surface landforms including toreva blocks longitudinal and transverse ridges en echelon ridges and hummocks are commonly developed corresponding to these surface morphologies a series of internal sedimentary structures including jigsaw structures inner shear zones aligned clasts diapiric structures convoluted laminations and basal decollements are also well developed through an analysis of these surficial and internal characteristics we propose that a rapid motion similar to a laminar flow most likely occurred after the avalanche mass detaching from the source area in this process the detached avalanche mass was mainly emplaced by a frictional simple shear process characterized by a bulldozing effect that occurred between the sliding mass and the substrate from the proximal to the distal sections of the avalanche the transport of the rock mass can be classified into four major processes an extension dominated sliding process in the transition zone a compression dominated sliding process in subzones iii 1 and iii 2 of the accumulation zone iii a sliding process co dominated by compression and lateral spreading in subzone iii 3 and a rapid radial spreading process in subzone iii 4 the results of our study provided an improved understanding of the transport mechanisms of this rock avalanche

global scale analysis of martian landslide mobility and paleoenvironmental clues the mobility of landslides on mars is studied based on a database of 3 118 events to establish the volume of the landslides for the whole dataset based on the deposit area a new volume area relationship based on a representative dataset of 222 landslides is used plotting the h l ratio between fall height h and runout l versus volume landslide mobility is analyzed and compared with existing empirical relationships for martian and terrestrial landslides analyzing the mobility in terms of normalized residuals i e the relative deviation of the h l ratio from the dataset best fit line mobility is found to depend on both the landslide location on mars and landslide typology this allows us to identify four different types of high mobility hypermobile landslides three classes of high mobility landslides are associated respectively to meteoroid impact the olympus mons aureoles and landslides with toreva block failure style and their mobility can be explained by the peculiar flow mechanics the fourth class includes landslides associated with isolated craters those in the regions wetted by the putative oceanus borealis and the ones at high latitudes we suggest that the common factor behind all the hypermobile landslides of this fourth kind is the presence of ice this is confirmed by our data showing that landslides increase in mobility with latitude the latitudinal trend mirrors the distribution of ice as detected by radar neutron probes and the presence of glacial and layered ejecta morphologies because the overall landslide distribution supports the presence of ice lubricated conditions two ice lubrication models are presented showing how ice melting within or underneath the landslides could enhance mobility by proper analysis in terms of apparent friction residuals we find that the mobility of landslides in valles marineris with the largest landslide concentration is lower than average we explain this circumstance partly from the smaller role of ice in equatorial valles marineris and partly because the collapses from high slope relief imply high speed impact with the floor valley confinement loss of momentum and decrease in mobility environmental consequences imply that the present subsurface ice distribution may have been persistent throughout the amazonian period

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

the pandemonium creek rock avalanche british columbia in 1959 a rock spur became detached from the headwall of a cirque near pandemonium creek in the southern coast mountains of british columbia approximately 5 000 000 cu m of blocky gneissic quartz diorite debris travelled 9 0 km along a highly irregular path descending a vertical distance of 2 km to the valley of south atnarko river the high mobility of the rock avalanche is manifested by superelevation in valley bends two run ups and two right angle changes in flow direction this mobility is due in part to 1 peculiarities in the path of the landslide lateral moraines for example funnelled and accelerated the debris and 2 travel over a glacier below the detachment zone although most of the debris came to rest on the upper part of a fan at the mouth of pandemonium creek one lobe traversed the fan and entered knot lakes where it generated displacement waves that destroyed trees along the shore run up and superelevation data indicate that the debris was moving between 81 and 100 m s as it entered the run up zone at pandemonium creek and 21 38 m s in pandemonium valley to the east these velocities were analysed by applying the dynamic model of h j korner rock mechanics 1976 8 225 256 to the path of the landslide the analysis suggests that the rock avalanche had two phases a very rapid initial phase from detachment to the beginning of the run up and following sudden energy losses at the run up a second phase involving much lower velocities the pandemonium creek landslide is similar in many respects to much larger highly mobile rock avalanches in other parts of the world for example huascaran peru and little tahoma peak washington u s a although much less common than rockfalls and debris flows rock avalanches are capable of far greater damage this is a consequence of their size and the fact that they travel great distances at high velocities the potential exists for other highly mobile landslides of the pandeminium creek type in the mountains of western canada highlighting the need for caution in the future development of this region

solute flux in meltwaters draining from a glacierized basin in the karakoram mountains electrical conductivity of meltwaters in the batura river which drains from the portal of batura glacier in the karakoram mountains was recorded continuously together with stage throughout an ablation season with the aim of estimating the annual total solute flux from the 56 glacier covered basin through time variations of meltwater cationic concentration were obtained from the electrical conductivity record using a rating curve established between sums of cations determined in periodically collected samples of meltwater and electrical conductivity measured at the times of sampling hourly average cationic flux was then obtained as the product of cationic concentration and discharge error arising as a result of inaccuracy in river gauging and use of the rating relationship electrical conductivity varied diurnally inversely with discharge overall level decreasing as discharge increased in spring continuing subdued through july and august irrespective of episodic discharge fluctuations in contrast solute flux mimicked discharge variation low solute concentrations being offset by the volume of water flowing total annual cationic flux from batura basin was 1 03 meq 15 assuming almost all of the flux was derived subglacially the solute flux from beneath batura glacier was 2 64 0 40 eq m 2 a 1 these rates of cationic denudation substantially higher than the continental average are at the top end of the global range of reasonably reliable estimates for other smaller glacierized basins carbonate lithology high annual runoff high sediment concentration in meltwaters and long subglacial pathways account for the high solute flux from batura glacier through longer residence times of meltwater in transit under ice and higher discharges dissolution kinetics and flow couple to enhance solute fluxes from larger glaciers although subglacial chemical denudation in the karakoram mountains is significant in carbon cycling at the continental scale such carbonate dissolution probably contributes little to net consumption of carbon dioxide from the atmosphere

detection of dual effects of degradation of perennial snow and ice covers on the hydrologic regime of a himalayan river basin by stream water availability modeling summary in river basins where melt water from snow and ice constitutes a dominant component of stream discharge during summer degradation or reduction of perennial snow and ice covered areas sca p has a profound effect on stream water availability in those basins degradation of sca p that includes glaciers is a globally widespread phenomenon observed in the recently past decades its cause has been attributed to global warming and its consequence is expected to dramatically alter the flow regimes of the rivers draining the terrains the predicted change in flow regime is an initial increase in summer flows in the early decades of 21st century followed by sharp decline of the same during the later parts of the century estimation of sca p within the upper indus basin uib straddling the western ranges of the greater himalayas karakoram mountains and the eastern mountain ranges of the hindu kush shows that from 1992 to 2010 there has been about 2 15 reduction in sca p a spatially distributed basin scale stream water availability model is presented to calculate monthly river discharges at critical hydrologic junctions within uib model calculations for the years 1992 2000 and 2008 show that due to the degradation of the sca p within the basin there has been significant decrease in summer discharges at various hydrologic junctions the percentage decline in flows varies from 10 to 22 depending on the locations of the junctions within the basin the space dependence of these variations reflects differential degradation of sca p in various parts of the basin furthermore the time of peak discharge at all of the hydrological junctions has shifted from middle late summer to late spring early summer as another outcome of sca p reduction such temporal shifting of nival regimes to early part of warmer season has also been predicted by global warming models however the case study presented here for a major himalayan river basin demonstrates that such shifting of peak discharge in the time domain can also take place simply due to retreat of the equilibrium line thus the effects of a warming climate have possibly been already set within uib instead of experiencing an increased pulse of summer flows for the next few decades summer flows within this basin are expected to decline changes in the timing of peak flows can have adverse effects on multipurpose water resources management without appropriate adaptation and mitigation measures monthly average stream flow data with 35 year period of record from a key gauging station support the findings of the model results similarly digital maps of sca p at different time periods within a key catchment of uib containing one of the major glaciers show retreat of glacial lobes and significant decrease in total sca p taking place during the past decades

mass balance studies on siachen glacier in the nubra valley karakoram himalaya india the hydrological method is used to compute the mass balance of siachen glacier in the nubra valley karakoram himalaya india the method was chosen because of its suitability in rugged terrain analysis of precipitation data from the glacier as a function of altitude shows a power law relationship accumulation estimates based on this relationship show good agreement with the recorded precipitation the discharge data from the glacier show high runoff in the ablation seasons of 1986 87 1987 88 1989 90 and 1990 91 the mass balance calculations for these years are negative the lowest being in 1990 91 1084 mm positive mass balance in 1988 89 358 mm is attributed to comparatively heavy winter snowfall amounts and comparatively low temperatures during the ablation season significantly lower runoff was measured during this season negative mass balance values during 1989 90 and 1990 91 are a result of comparatively dry winters and comparatively warm ablation periods with monthly mean air temperatures 1 4 5 1 c higher at the beginning of the ablation season june and july than the mean of the last 5 years

a physically based model for the topographic control on shallow landsliding a model for the topographic influence on shallow landslide initiation is developed by coupling digital terrain data with near surface through flow and slope stability models the hydrologic model topog o loughlin 1986 predicts the degree of soil saturation in response to a steady state rainfall for topographic elements defined by the intersection of contours and flow tube boundaries the slope stability component uses this relative soil saturation to analyze the stability of each topographic element for the case of cohesionless soils of spatially constant thickness and saturated conductivity the steady state rainfall predicted to cause instability in each topographic element provides a measure of the relative potential for shallow landsliding the spatial distribution of critical rainfall values is compared with landslide locations mapped from aerial photographs and in the field for three study basins where high resolution digital elevation data are available tennessee valley in marin county california mettman ridge in the oregon coast range and split creek on the olympic peninsula washington model predictions in each of these areas are consistent with spatial patterns of observed landslide scars although hydrologic complexities not accounted for in the model e g spatial variability of soil properties and bedrock flow control specific sites and timing of debris flow initiation within areas of similar topographic control

recent and future warm extreme events and high mountain slope stability the number of large slope failures in some high mountain regions such as the european alps has increased during the past two to three decades there is concern that recent climate change is driving this increase in slope failures thus possibly further exacerbating the hazard in the future although the effects of a gradual temperature rise on glaciers and permafrost have been extensively studied the impacts of short term unusually warm temperature increases on slope stability in high mountains remain largely unexplored we describe several large slope failures in rock and ice in recent years in alaska new zealand and the european alps and analyse weather patterns in the days and weeks before the failures although we did not find one general temperature pattern all the failures were preceded by unusually warm periods some happened immediately after temperatures suddenly dropped to freezing we assessed the frequency of warm extremes in the future by analysing eight regional climate models from the recently completed european union programme ensembles for the central swiss alps the models show an increase in the higher frequency of high temperature events for the period 2001 2050 compared with a 1951 2000 reference period warm events lasting 5 10 and 30 days are projected to increase by about 1 5 4 times by 2050 and in some models by up to 10 times warm extremes can trigger large landslides in temperature sensitive high mountains by enhancing the production of water by melt of snow and ice and by rapid thaw although these processes reduce slope strength they must be considered within the local geological glaciological and topographic context of a slope

regional differences in response of flow in glacier fed himalayan rivers to climatic warming river flow from glacierized areas in the himalaya is influenced both by intra annual variations in precipitation and energy availability and by longer term changes in storage of water as glacier ice high specific discharge from ice melt often dominates flow for considerable distances downstream particularly where other sources of runoff are limited providing a major water resource should himalayan glaciers continue to retreat rapidly water shortages might be widespread within a few decades however given the difference in climate between the drier western and monsoonal eastern ends of the region future warming is unlikely to affect river flow uniformly throughout a simple temperature index based hydro glaciological model in which glacier dimensions are allowed to decline through time has been developed with a view to assessing in data sparse areas by how much and when climate warming will reduce himalayan glacier dimensions and affect downstream river flows two glaciers having the same initial geometries were located one each in the headwaters of two identical nests of hypothetical catchments representing contrasting climates in the west and east of the region the hypothetical catchments were nested such that percentage ice cover declined with increasing basin area model parameters were validated against available but limited mass balance and river flow measurements the model was applied for 150 years from an arbitrary start date 1990 first with standard period 1961 1990 climate data and then with application of a 0 06 c year 1 transient climatic warming scenario under this warming scenario himalayan rivers fed by large glaciers descending through considerable elevation range will respond in a broadly similar manner except that summer snowfall in the east will suppress the rate of initial flow increase delay peak discharge and postpone eventual disappearance of the ice impacts of declining glacier area on river flow will be greater in smaller and more highly glacierized basins in both the west and east and in the west where precipitation is scarce for considerable distances downstream copyright 2006 john wiley sons ltd

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

interpretation of the chemical and physical time series retrieved from sentik glacier ladakh himalaya india analyse a partir de mesures de la radioactivite d analyses chimiques chlorures sodium fer silicates phosphates ammonium d 18 o et ph et de donnees physiques des variations cycliques temporelles des glaciers application aux paleoclimats

separating snow clean and debris covered ice in the upper indus basin hindukush karakoram himalayas using landsat images between 1998 and 2002 summary the hindukush karakoram himalayan mountains contain some of the largest glaciers of the world and supply melt water from perennial snow and glaciers to the upper indus basin uib upstream of tarbela dam which constitutes greater than 80 of the annual flows and caters to the needs of millions of people in the indus basin it is therefore important to study the response of perennial snow and glaciers in the uib under changing climatic conditions using improved hydrological modeling glacier mass balance and observations of glacier responses however the available glacier inventories and datasets only provide total perennial snow and glacier cover areas despite the fact that snow clean ice and debris covered ice have different melt rates and densities this distinction is vital for improved hydrological modeling and mass balance studies this study therefore presents a separated perennial snow and glacier inventory perennial snow cover on steep slopes perennial snow covered ice clean and debris covered ice based on a semi automated method that combines landsat images and surface slope information in a supervised maximum likelihood classification to map distinct glacier zones followed by manual post processing the accuracy of the presented inventory falls well within the accuracy limits of available snow and glacier inventory products for the entire uib estimates of perennial and or seasonal snow on steep slopes snow covered ice clean and debris covered ice zones are 7238 724 5226 522 4695 469 and 2126 212 km2 respectively thus total snow and glacier cover is 19 285 1928 km2 out of which 12 075 1207 km2 is glacier cover excluding steep slope snow cover equilibrium line altitude ela estimates based on the snow line elevation sle in various watersheds range between 4800 and 5500 m while the accumulation area ratio aar ranges between 7 and 80 0 c isotherms during peak ablation months july and august range between 5500 and 6200 m in various watersheds these outputs can be used as input to hydrological models to estimate spatially variable degree day factors for hydrological modeling to separate glacier and snow melt contributions in river flows and to study glacier mass balance and glacier responses to changing climate

landslide hazard evaluation a review of current techniques and their application in a multi scale study central italy in recent years growing population and expansion of settlements and life lines over hazardous areas have largely increased the impact of natural disasters both in industrialized and developing countries third world countries have difficulty meeting the high costs of controlling natural hazards through major engineering works and rational land use planning industrialized societies are increasingly reluctant to invest money in structural measures that can reduce natural risks hence the new issue is to implement warning systems and land utilization regulations aimed at minimizing the loss of lives and property without investing in long term costly projects of ground stabilization government and research institutions worldwide have long attempted to assess landslide hazard and risks and to portray its spatial distribution in maps several different methods for assessing landslide hazard were proposed or implemented the reliability of these maps and the criteria behind these hazard evaluations are ill formalized or poorly documented geomorphological information remains largely descriptive and subjective it is hence somewhat unsuitable to engineers policy makers or developers when planning land resources and mitigating the effects of geological hazards in the umbria and marche regions of central italy attempts at testing the proficiency and limitations of multivariate statistical techniques and of different methodologies for dividing the territory into suitable areas for landslide hazard assessment have been completed or are in progress at various scales these experiments showed that despite the operational and conceptual limitations landslide hazard assessment may indeed constitute a suitable cost effective aid to land use planning within this framework engineering geomorphology may play a renewed role in assessing areas at high landslide hazard and helping mitigate the associated risk

the tsiolkovskiy crater landslide the moon an lroc view abstract evidence suggests that the lobate flow feature that extends 72 km outward from the western rim of tsiolkovskiy crater is a long runout landslide this landslide exhibits three possibly four morphologically different parts likely caused by local conditions all of these plus the ejecta of tsiolkovskiy crater and its mare fill are approximately of the same crater model age i e 3 55 0 1 ga the enormous size of this landslide is unique on the moon and is a result of a combination of several geometric factors e g its location relative to fermi crater and that tsiolkovskiy crater was an oblique impact that produced an ejecta forbidden zone on its western side schultz 1976 the landslide formed in this ejecta free zone as the rim of tsiolkovskiy collapsed and its debris flowed across the relatively smooth flat floor of fermi crater in this location it could be easily identified as a landslide and not ejecta its mobility and coefficient of friction are similar to landslides in valles marineris on mars but less than wet or even dry terrestrial natural flows this suggests that the mars landslides may have been emplaced dry the high density of small craters on the landslide is likely an illusion caused by the effects of age related differences in regolith thickness on crater morphology and the presence of the abundant young circular secondary craters produce by debris ejected from distant fresh craters

a joint analysis of river runoff and meteorological forcing in the karakoram upper indus basin satellite geodetic altimetry investigations in the karakoram have indicated slight mass gain or loss of the glaciers during the early part of 21st century equivalent discharge in the upper indus basin uib due to these mass changes has been estimated at 5 to 10 of mean annual flow however satellite altimetry and geodetic glacier mass estimates in the extreme topography of the karakoram have not yet been counter validated by hydrological analysis therefore we present a first cross validation of three to five decades of river flow data from the three major watersheds in the karakoram with matching series of monthly precipitation temperature and evaporation provided by six atmospheric reanalysis products for 1979 2014 the analyses suggest that in most cases river flows have been increasing steadily from the end of the 1960 s and 1970 s to the middle of the 1990 s and have stabilized or are in decline since then hunza watershed in karakoram west shows consistently declining flows over the first half of the analysis period and stable flows during the second half for most of the summer melting season suggesting mass accumulation rising river flows in the shyok and shigar watersheds followed by stabilizing or slightly declining flows from 1995 onward can be explained by consistently increasing precipitation during the first half of the analysis period and successive stabilization or minor decline thereof flow data do not necessarily suggest considerable loss or gain of glacial mass in the karakoram during the late 90 s and early 2000 s as suggested by satellite based altimetry studies

the little ice age as recorded in the stratigraphy of the tropical quelccaya ice cap the analyses of two ice cores from a southern tropical ice cap provide a record of climatic conditions over 1000 years for a region where other proxy records are nearly absent annual variations in visible dust layers oxygen isotopes microparticle concentrations conductivity and identification of the historical a d 1600 huaynaputina ash permit accurate dating and time scale verification the fact that the little ice age about a d 1500 to 1900 stands out as a significant climatic event in the oxygen isotope and electrical conductivity records confirms the worldwide character of this event

rainfall thresholds for the activation of shallow landslides in the italian alps the role of environmental conditioning factors abstract the aim of the present work is to investigate the role exerted by selected environmental factors in the activation of rainfall triggered shallow landslides and to identify site specific rainfall thresholds the study concerns the italian alps the region is exposed to widespread slope instability phenomena due to its geological morphological and climatic features furthermore the high level of anthropization that characterizes wide portions of the territory increases the associated risk hence the analysis of potential predisposing factors influencing landslides triggering is worthwhile to improve the current prediction skills and to enhance the preparedness and the response to these natural hazards during the last years the italian national research council s research institute for hydro geological protection cnr irpi has contributed to the analysis of triggering conditions for rainfall induced landslides in the framework of a national project the project funded by the national department for civil protection dpc focuses on the identification of the empirical rainfall thresholds for the activation of shallow landslides in italy the first outcomes of the project reveal a certain variability of the pluviometric conditions responsible for the mass movements activation when different environmental settings are compared this variability is probably related to the action of local environmental factors such as lithology climatic regime or soil characteristics based on this hypothesis the present study aims to identify separated domains within the italian alps where different triggering conditions exist and different countermeasures are needed for risk prevention for this purpose we collected information concerning 511 landslides activated in the period 2000 2012 and reconstructed 453 rainfall events supposed to be responsible for the activations then we selected a set of thematic maps to represent the hypothesised landslide conditioning factors and to identify the supposed homogeneous domains within the study area we employed an existing statistical method for the definition of the cumulated event rainfall vs rainfall duration ed thresholds for both the entire catalogue of rainfall events and for the events falling in the separated domains the obtained results contribute to a better understanding of the role exerted by geological pedological and climatic factors in landslides activation and help identifying separated domains where different risk managing strategies should be adopted the proposed methodology can be a valid support for risk reduction strategies planning at regional scale

rheological constraints on martian landslides we use a dynamic finite difference model to simulate martian landslides in the valles marineris canyon system and olympus mons aureole using three different modal rheologies frictional bingham and power law the frictional and bingham modes are applied individually fluidized rheology is treated as a combination of frictional and power law modes general fluidization can include pore pressure contributions whereas acoustic fluidization does not we find that general fluidization most often produces slides that best match landslide geometry in the valles marineris this implies that some amount of supporting liquid or gas was present in the material during failure the profile of the olympus mons aureole is not well matched by any landslide model suggesting an alternative genesis in contrast acoustic fluidization produces the best match for a lunar slide a result anticipated for dry crust with no overlying atmosphere the presence of pressurized fluid during valles marineris landsliding may be due to liquid water beneath a thin cryosphere 1 2 km or flash sublimation of co2

a gis physically based emergency methodology for predicting rainfall induced shallow landslide zonation abstract this study proposes an original approach for predicting shallow translational slide hazards which are triggered by irregular rainfall events via the method of zonation at a regional scale in emergency situations the proposed model incorporates the infinite slope method in a gis platform to assess hazard and risk associated with slope instability this application can be integrated into the emergency management software simge 1 0 sge 2 0 the objective of the work is to provide a quick tool for managing emergencies and predicting shallow rainfall induced landslides rils the originality of this approach includes the relationship between two variables m z with m being a hydrological pattern of steady state simulating the effects of rain that cause translational slides and z being the characteristic sliding depth based on the bounded lithological unit this method provides hazard maps including zonation based on a factor of safety towards shallow landslides where stable and unstable conditions depending on precipitation are determined for managing emergencies this approach was applied in the guadalmansa river basin in benahavis malaga andalusia where numerous shallow landslides occurred in 2010 caused by extreme rainfall events and a lithological unit has been isolated for this research alpujarride schist the results obtained through this method have been verified after analysing the studied area s landslide inventory

a reevaluation of the snowmelt and glacial melt in river flows within upper indus basin and its significance in a changing climate summary the hydrograph separation method previously proposed to quantify base flow seasonal snowmelt and glacial melt components in river flows within upper indus basin underestimates glacial melt component this is particularly limiting for highly glacierized watersheds the limitation has been corrected by a further refinement of the method the results with the refined procedure are highly consistent with the physical characteristics such as hypsometry and glacier extents of the watershed even though the method itself is completely independent of the physical characteristics of the watershed where it is applied glacial melt far outweigh snowmelt in the rivers draining the karakoram and zanskar ranges in the karakoram on an annualized basis glacial melt proportion varies from 43 to 50 whereas snowmelt varies from 27 to 31 on the other hand snowmelt dominates over glacial melt in the rivers draining the western greater himalayas and the hindu kush here snowmelt percentage in river discharge varies from 31 to 53 whereas that of glacial melt ranges from 16 to 30 in the main stem of upper indus river snowmelt fraction in most cases is slightly greater than the glacial melt fraction in the main stem snowmelt percentage ranges from 35 to 44 whereas glacial melt percentage ranges from 25 to 36 upper indus river just upstream of tarbela reservoir carries annual flows constituted of 70 melt water of which 26 is contributed by glacial melts and 44 by snowmelts we also show that during the later part of twentieth century and continuing into the early part of twenty first century glacial melt contributions to river discharge has decreased compared to the previous decades this phenomenon can be ascribed to either basin wide loss of glacial mass in the recent decades in the elevation range from where most of the glacial melt originates or glacier growth and stability due to either reduction in energy inputs or increase in precipitation or both at the high altitude bands wherefrom glacial melt water originates

rock avalanche mobility the role of path material abstract rock avalanches are high velocity flows of fragmented rock that can dramatically alter landscapes and impact people and infrastructure far from their source these catastrophic events have been studied for over a century however a consensus regarding the mechanism s that govern their motion has yet to emerge this work details the results of the back analysis of 45 rock avalanche case histories using a semi empirical runout model that simulates motion over 3d terrain these simulations account for topographic effects and bulk basal shear resistance variation during motion for a subset of the cases we find that a volume dependent mechanism appears to influence basal resistance in the source zone however once the material has vacated the source zone our results suggest that the character of the path material strongly controls mobility and appears to dominate over other potentially volume dependent mechanisms that may also be at work the results presented in this paper support the longstanding hypothesis that the interaction of flowing debris with the underlying substrate is an important consideration in rock avalanche runout prediction and that this mechanism warrants further research

last glacial maximum climate based on cosmogenic 10be exposure ages and glacier modeling for the head of tashkurgan valley northwest tibetan plateau abstract fully understanding the timing and climate of last glacial maximum lgm is still lack in the head of the tashkurgan valley northwest tibetan plateau tp the recent improvements in cosmogenic 10 be exposure dating and glacier modeling present an opportunity to estimate the lgm climatic conditions in the paper we investigated the moraines and used the 10 be exposure dating on the moraine boulders to constrain the timing of the lgm the kuzigun glacial stage in the head of the tashkurgan valley then we used a coupled mass balance and ice flow model to quantify the paleoclimate from past glacier extents constrained by mapped and dated kuzigun glacial moraines in the area we showed that the glaciers terminated at an elevation of 4100 4200 m asl during the kuzigun glacial stage and the glacial stage occurred during or slightly before 15 23 ka corresponding to the timing of the global lgm the modeled mass balances indicated that present day equilibrium line altitude ela ranges from 5150 to 5250 m asl and lgm ela is between 4550 and 4600 m asl in the area suggesting an ela lowering of 600 m during the lgm model results suggested that the temperature during the lgm in the head of the tashkurgan valley is 5 8 c colder than today considering a 30 70 reduction in precipitation compared to today the paleoclimate estimates are generally consistence with previous studies that showed the lgm climate was colder and drier than today on the tp

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

calibration and validation of rainfall thresholds for shallow landslide forecasting in sicily southern italy abstract empirical rainfall thresholds are tools to forecast the possible occurrence of rainfall induced shallow landslides accurate prediction of landslide occurrence requires reliable thresholds which need to be properly validated before their use in operational warning systems we exploited a catalogue of 200 rainfall conditions that have resulted in at least 223 shallow landslides in sicily southern italy in the 11 year period 2002 2011 to determine regional event duration cumulated event rainfall ed thresholds for shallow landslide occurrence we computed ed thresholds for different exceedance probability levels and determined the uncertainty associated to the thresholds using a consolidated bootstrap nonparametric technique we further determined subregional thresholds and we studied the role of lithology and seasonal periods in the initiation of shallow landslides in sicily next we validated the regional rainfall thresholds using 29 rainfall conditions that have resulted in 42 shallow landslides in sicily in 2012 we based the validation on contingency tables skill scores and a receiver operating characteristic roc analysis for thresholds at different exceedance probability levels from 1 to 50 validation of rainfall thresholds is hampered by lack of information on landslide occurrence therefore we considered the effects of variations in the contingencies and the skill scores caused by lack of information based on the results obtained we propose a general methodology for the objective identification of a threshold that provides an optimal balance between maximization of correct predictions and minimization of incorrect predictions including missed and false alarms we expect that the methodology will increase the reliability of rainfall thresholds fostering the operational use of validated rainfall thresholds in operational early warning system for regional shallow landslide forecasting

rates of basin wide rockwall retreat in the k2 region of the central karakoram defined by terrestrial cosmogenic nuclide 10be abstract basin wide rockwall retreat rates are estimated using cosmogenic 10 be concentrations in supraglacial debris from the baltoro glacier basin in k2 region of the central karakoram pakistan total cosmogenic 10 be concentrations of the supraglacial debris were measured using accelerator mass spectrometry to determine 10 be concentrations inherited from the rockwalls within the glaciated basin given that rockfall induced by periglacial weathering and snow and ice avalanches is the most important source of supraglacial debris production in the high mountain glaciated basin the erosion rate of the bare bedrock can be considered to be the rate of rockwall retreat the rate of the rockwall erosion converted from the calculated inheritance of 10 be concentrations using the maximum velocity of the active glacier places an upper limit ranging from 0 65 mm year to 2 48 mm year this rate of rockwall retreat is in the same order of magnitude reported in other high himalayan mountains the rate however is an order of magnitude higher than erosion rates inferred from sediment budget studies and half that of the fluvial incision rate and exhumation rate for the same region the difference between rates of basin wide rockwall retreat and fluvial incision rates over the late quaternary suggests that in this glaciated basin fluvial incision is likely enhanced by localized differential tectonism and or isostatic uplift

modelling rock avalanche propagation onto glaciers abstract ice rock avalanches which occur in glacial environments are controlled by the presence of snow and ice in the moving material and by possible propagation onto icy basal surfaces all these factors contribute to enhancing the flow mobility mixing with ice and snow hampers block collisions and favours dense flow behaviour ice melting reduces granular friction by saturation of the basal material and fluidization effects propagating onto glaciers offers a smooth surface with low shear resistance this work is a review of the best documented ice rock avalanches and focuses on evaluating their mobility for hazard analysis purposes by providing a set of calibrated cases the rock avalanches have volumes ranging from 5 10 6 m 3 to 25 10 6 m 3 we replicate these events by using sph and fem numerical methods assuming frictional and voellmy basal rheologies the voellmy rheology best performs at replicating the landslide propagation among the back analyzed cases the frictional coefficient ranges in the interval 0 03 0 1 the turbulent coefficient within 1000 m s 2 2000 m s 2 the bulk basal friction angle ranges within 2 75 and 14 with values inversely related to event volumes forward selection of the basal friction angle based on event volume allows the replication of the mount cook ice rock avalanche predicting a maximum runout which is less than 4 larger than observed in the perspective of forward modelling large uncertainty is related to the reconstruction of the post event topographies particularly for the sliding surface mixing with ice and snow reduces basal friction proportionally to ice and snow content pure ice has a basal friction which is reduced by about 75 than basal friction of pure rock melting of ice during rock avalanche propagation has been evaluated for the sherman event the frictional heat generated at the glacier surface results in the melting of 86 2 5 9 kg m 2 which could have contributed to a minimum 20 35 10 reduction of the material friction angle through the sole pore pressure generation within a 40 and 20 cm thick shear layer respectively the largest uncertainty is related to the area of contact between rock and ice

how large is the upper indus basin the pitfalls of auto delineation using dems summary extraction of watershed areas from digital elevation models dems is increasingly required in a variety of environmental analyses it is facilitated by the availability of dems based on remotely sensed data and by geographical information system gis software however accurate delineation depends on the quality of the dem and the methodology adopted this paper considers automated and supervised delineation in a case study of the upper indus basin uib pakistan for which published estimates of the basin area show significant disagreement ranging from 166 000 to 266 000 km 2 automated delineation used arcgis archydro and hydrology tools applied to three good quality dems two from srtm data with 90m resolution and one from 30m resolution aster data automatic delineation defined a basin area of c 440 000 km 2 for the uib but included a large area of internal drainage in the western tibetan plateau it is shown that discrepancies between different estimates reflect differences in the initial extent of the dem used for watershed delineation and the unchecked effect of iterative pit filling of the dem going beyond the filling of erroneous pixels to filling entire closed basins for the uib we have identified critical points where spurious addition of catchment area has arisen and use google earth to examine the geomorphology adjacent to these points and also examine the basin boundary data provided by the hydrosheds database we show that the pangong tso watershed and some other areas in the western tibetan plateau are not part of the uib but are areas of internal drainage our best estimate of the area of the upper indus basin at besham qila is 164 867 km 2 based on the srtm dem and 164 853 km 2 using the aster dem this matches the catchment area measured by wapda swhp an important lesson from this investigation is that one should not rely on automated delineation as iterative pit filling can produce spurious drainage networks and basins when there are areas of internal drainage nearby

rainfall intensity duration thresholds for the initiation of landslides in zhejiang province china abstract zhejiang province located in the southeast coastal region of china is highly prone to rainfall triggered landslides because of its geologic geomorphologic and climatic settings the rainfall landslide relationship is critically important for predicting rainfall induced landslides this study defines landslide triggering rainfall intensity duration thresholds for the entire zhejiang region and the 62 individual areas that comprise the region based on 1569 shallow landslides which occurred from 1990 to 2013 and their corresponding detail rainfall records from 2457 rain gauges in the region the results indicate that the rainfall thresholds vary spatially over the region for rainfall durations from 1 to 24 h the threshold tends to increase from the northwestern part of zhejiang to its southeastern coastal region and it is lower in the central and coastal hill basin regions than that in the western and southern mountainous regions variability of the threshold in space is mainly affected by the slope forming materials and terrain slope gradients different soil types have different thresholds and the thresholds for weathered rock slides are generally higher than those for soil slides for the soil weathered rock on slopes the slope gradient has no obvious influence on the thresholds when the slope angle is

rising river flows and glacial mass balance in central karakoram summary field observations and geodetic measurements suggest that in the central part of the karakoram mountains glaciers are either stable or expanding since 1990 in sharp contrast to glacier retreats that are prevalent in the himalayas and adjoining high altitude terrains of central asia decreased discharge in the rivers originating from karakoram is cited as a supporting evidence of this somewhat anomalous phenomenon here in contrary to those citations we show that river discharge during the melting season of the glaciers in central karakoram has increased from 1985 to 2010 we have implemented a sophisticated statistical procedure involving non parametric tests combined with a benchmark smoothing technique that has proven to be a powerful method for empirical trend analysis to remove the stochastic component from the trend component in a time series melt water from winter snows is the dominant constituent of june and july flows glacial melts predominantly contribute to august and partially to september flows which are controlled by monsoonal snowfall too at elevations approximately 3500 m for all four summer months flows increased from 1985 to 2000 august flows which actually reflect the states of the glaciers have continued to rise steadily after 2000 at the same rate as those did for the period 1985 2000 however the rising trends of june and july flows changed to slightly declining trends from 2000 to 2010 these trends most likely indicate drop in winter snowfall over karakoram and do not provide direct indications about the states of the glaciers the rising trend of august discharge is due to change in glacial storage at a steadily decreasing rate of approximately 0 04 0 05 mm day year for the period 1985 2010 this rate is nearly equal to the rate of increase in precipitation during the summer months over karakoram mountains in recent decades as determined from the era 40 and gpcp precipitation datasets thereby this is most plausibly why the glacial mass balance in central karakoram is nearly neutral the rising river flows accompanying non negative glacier mass balance are consistent with predicted future river flows derived from hydrologic modeling coupled with a climate projection suggesting increasing temperature and precipitation with unchanged glacier covers this investigation reconciles two apparently contradictory observations namely rising river flows and either zero or slightly positive mass balance of central karakoram glaciers

geochemistry of the amazon 1 precipitation chemistry and the marine contribution to the dissolved load at the time of peak discharge analyses of precipitation and surface water are used to estimate the fluxes of marine cyclic salts through that part of the amazon river system draining past obidos 80 of the basin at the time of peak discharge in june amazon precipitation chemistry can be devided into two principal components marine and terrestrial the marine component determined from analyses of marine rain consists of na k mg ca and cl in approximately sea salt proportions with s doubly enriched the excess sulfur is probably derived from gas phase inputs the terrestrial component makes an important contribution of k ca s and n much of which can be related to biological emissions the emission of reduced sulfur in the marine and terrestrial environment and nitrogen in the terrestrial environment is responsible for a natural acid rain in the amazon region with a ph from 4 7 to 5 7 this is about one tenth the acidity of polluted urban rain the chloride content of lowland rivers which drain regions lacking significant geologic sources of chloride shows a systematic decrease in chloride with increasing distance from the ocean this trend is used to define the cyclic salt background for amazonian surface waters cyclic salts in general make only a minor contribution relative to terrestrial inputs to the chemistry of amazon basin rivers even those draining intensely weathered terrains an estimated 17 6 cl 6 9 na 1 3 mg 3 6 s 0 4 k and 0 1 ca of the dissolved load at obidos during peak discharge is cyclic

seasonal and spatial variations in the chemistry of a high arctic supraglacial snow cover this paper describes the physical and chemical properties of the snowpack on john evans glacier ellesmere island canadian arctic archipelago and investigates the controls on snowpack solute concentrations and atmospheric deposition the snowpack contains three layers that are traceable across the whole glacier these represent fall accumulation that has been metamorphosed to depth hoar winter accumulation mixed with snow reworked by wind from the underlying depth hoar and spring accumulation mixed with wind reworked snow the seasonal cycle in snow chemistry closely reflects changes in the composition of the atmospheric aerosol at alert with some modification of no 3 concentrations by post depositional processes mean water weighted solute concentrations in the snowpack are largely independent of accumulation while atmospheric deposition tends to increase with accumulation this suggests that for most species wet deposition is the dominant depositional process throughout the year however concentrations of ca 2 and k increase with both accumulation and elevation implying an enhanced input from dry deposition of soil dust above 800 m elevation concentrations of so 4 2 are inversely related to accumulation especially in the winter layer suggesting a significant input from non precipitating events such as dry deposition or riming during this period of very limited snowfall

glaciological characteristics of the ablation zone of baltoro glacier karakoram pakistan baltoro glacier in the karakoram pakistan is one of the world s largest valley glaciers it drains an area of about 1500 km 2 and is 60km long in 2004 an italian german expedition carried out a glaciological field program on the ablation zone of the glacier focusing on the ablation conditions and the dynamic state of the glacier as baltoro glacier is a debris covered glacier ice ablation also depends on the debris properties stake measurements of ice ablation and debris cover in combination with meteorological data from automatic weather stations close by have been used to determine the local melt conditions results from these calculations have been combined with an analysis of different classes of surface cover and information about precipitation using remote sensing techniques in order to calculate mass fluxes for the upper part of baltoro glacier the dynamic state of the glacier has been investigated by gps based surface velocity measurements along the stake network a comparison of these short term measurements during the melt season with surface velocities computed from feature tracking of satellite images shows a high seasonal variability of the ice motion we have shown that this variability is up to 100 of the annual mean velocity on the basis of these investigations the mass fluxes at the concordia cross section have been quantified this approach can now be used together with the ablation calculations to reconstruct the variability of glacier extent and volume in the past using available climate data from the central karakoram from the comparison of historical measurements and photographs it is shown that the snout of baltoro glacier is oscillating back and forth a couple of hundred metres otherwise it seems not to react with the same magnitude as other glaciers to the climatic change elevation changes at concordia are a few tens of metres at the most

evaluating triggering and causative factors of landslides in lawnon river basin taiwan this study evaluates triggering and causative factors of landslides by comparing their occurrence in the lawnon river basin prior to and after rainfall and earthquake events over a five year period 2005 2009 the landslide ratio in the study area was low less than 4 before 2007 and significantly increased in the wake of typhoon morakot in 2009 the high accumulation of rainfall was the major triggering factor in addition the major seismic activity of march 4 2008 also contributed to landslide occurrence the combined influence of rainfall and the earthquake is evaluated based on multi variable regression analysis though no significant co seismic landslides were found after the march 4 2008 earthquake its influence on slope stability has been observed from the apparent growth of landslide ratio in the four rainfall events following the quake causative factors include the higher landslide ratios occurring in sedimentary rock zones especially sandstone formations with intercalations of shale and dip slopes which are demonstrably prone to plane failures

an overview of recent large catastrophic landslides in northern british columbia canada at least thirty eight large catastrophic landslides each either larger than 0 5 m m 3 or longer than 1 km have occurred in northern british columbia in the last three decades the landslides include low gradient flowslides in cohesive sediments long runout rock slides rock avalanches and complex rock slide flows the flowslides have occurred in a variety of sediments including glaciolacustrine silt clay rich till and clay rich colluvium the rock failures have happened in weak shale overlain by sandstone and volcanic rocks the frequency of large landslides in northern british columbia appears to be increasing suggesting a link to climate change d 2005 elsevier b v all rights reserved

a warning system for rainfall induced shallow failures abstract it is widely recognised that soil slips and debris flows are triggered by short intense storms owing its geologic geomorphologic and climatic settings the piedmont region nw italy is highly prone to the occurrence of this kind of landslides in the last two centuries in fact a total of 105 severe meteoric events which triggered shallow failures occurred and of these 18 events took place from 1990 to 2002 a fair number of rainfall thresholds have been proposed in the literature defined both on empirical or on physical bases empirical thresholds are defined collecting rainfall data for landslide meteoric events and for events without landslides while physical thresholds are based on numerical models that consider the relation between rainfall pore pressure and slope stability the main objective of this paper is the identification of the empirical triggering thresholds for the piedmont region four meteoric events were selected and analysed november 4 5 1994 july 7 8 1996 april 27 30 2000 october 13 16 2000 because they supply a wide range of variation for both rainfall parameters duration intensity cumulative rainfalls and the number of induced landslides in the intensity duration plot the critical limit is described by the equation i 19d 0 50 where i rainfall intensity expressed in mm h and d rainfall duration expressed in hours such a limit is traced to envelop 90 of the points on the graph in the ni d diagram the triggering thresholds are given by the equations ni 0 76d 0 33 and ni 4 62d 0 79 where ni normalised intensity with respect to the annual precipitation map expressed in mm h pma 100 in the article the different meaning of these thresholds is discussed finally the diagram ni ncr is proposed the triggering threshold is given by the expression ni 0 09ln ncr 0 54 where ncr is the normalised cumulative critical rainfall mm pma 100 the application of the triggering thresholds as a fundamental element in a warning system dedicated to the safeguarding of population in landslide prone areas is discussed in detail an operating procedure which is presently being verified and tested in the studied area is described

slight mass gain of karakoram glaciers in the early twenty first century the mass balance of hindu kush karakoram himalaya glaciers has been debated partly because of a severe lack of observations from the region an analysis of the regional mass balance of karakoram glaciers by comparison of digital elevation models from 1999 to 2008 reveals a small glacier mass gain in the area

one million cubic kilometers of fossil ice in valles marineris relicts of a 3 5 gy old glacial landsystem along the martian equator abstract self consistent landform assemblages suggest that valles marineris the giant valley system that stretches along the martian equator was entirely glaciated during late noachian to early hesperian times and still contains huge volumes of fossil ice some of these glacial landform assemblages are illustrated here with representative examples selected in three regions ius chasma central candor chasma and the junction between coprates chasma and capri chasma a morphological boundary separating an upper spur and gully morphology from a smooth basal escarpment has been spectacularly preserved along valley walls throughout valles marineris the boundary winds around topographic obstacles and displays long wavelength variations in elevation it is associated with lateral benches hanging valleys and truncated spurs comparisons with terrestrial analogs indicate that it is most reasonably interpreted as a glacial trimline chasma floors are covered by various kinds of terrains including hummocky terrains platy terrains lateral banks layered benches and a draping mantle landforms in these terrains and their spatial relationship with the interpreted trimline suggest that they correspond to various disintegration stages of an ancient glacial fill currently protected by a superficial cover of ablation till altogether these landforms and terrains compose a full glacial landsystem with wet based glaciers that were able to flow and slide over their beds it was most probably fed by ice accumulating at low elevations directly from the atmosphere onto valley floors and walls with only minor contributions from tributary glaciers flowing down from higher elevations similar fossil glacial landsystems dating back from the early martian history are to be expected in many other low latitude troughs such as chasmata chaos valleys impact craters and other basins

mobility of large rock avalanches evidence from valles marineris mars measurements of h l height of drop length of runout vs volume for landslides in valles marineris on mars show a trend of decreasing h l with increasing volume this trend which is linear on a log log plot is parallel to but lies above the trend for terrestrial dry rock avalanches this result and estimates of 10 4 to 10 5 pa yield strength suggest that the landslides were not water saturated as suggested by previous workers the offset between the h l vs volume trends shows that a typical martian avalanche must be nearly two orders of magnitude more voluminous than a typical terrestrial avalanche in order to achieve the same mobility this offset might be explained by the effects of gravity on flows with high yield strengths these results should prove useful to future efforts to resolve the controversy over the mechan ics of long runout avalanches

fragmentation in the val pola rock avalanche italian alps 1 grain size data from the deposit of the 1987 val pola rock avalanche central italian alps are compared with data concerning rock avalanching rock fragmentation and comminution the weibull distribution fits a small part of the entire particle size distribution of debris samples with a mean value of the curve shape factor of 0 54 0 28 this is typical of multiple comminution or fragmentation with much shearing a fractal distribution fits over a greater size range computed fractal dimensions range between 1 3 and 3 2 within the deposit with average values of about 2 6 2 7 these values cover the range between the theoretical values of the plane of weakness model 1 97 and the pillar of strength model 2 84 and are close to the theoretical value for the constrained comminution model 2 58 these suggest that both texturally mature and immature deposits are present and that more than a single comminution process acted during the rock avalanche motion variation of the grain size distribution within the deposit and grain size segregation show as trends in the fractal dimension and arise from variation in the fragmentation process a variety of different physical and empirical laws suggest that 1 30 of the energy expended in the rock avalanche was consumed in fragmentation

failure mechanisms and triggering factors in calcareous cliffs of the subalpine ranges french alps in order to enhance the detection of prospective rock falls in calcareous cliffs 25 rock falls have been described in a more detailed way than for an inventory they are representative of middle size rock falls 10 to 100 000 m3 occurring in the french subalpine ranges at an elevation between 200 m and 2 000 m structural conditions of the rock masses morphology of the initial cliff surface and the scar possible failure mechanisms and processes have been studied typical failure configurations have been identified based on the attitude of the failure surface in relation to the bedding planes and the cliff surface irregular cliff morphology appears to be another important susceptibility factor in most cases the classical comparison of the average planes of the main joint sets with the average plane of the slope could not define the potentially unstable masses rather those ones are due to joint planes that deviate from their mean set plane or to irregularities of the cliff surface the proposed investigation method to detect prospective rock falls mainly consists in observing stereoscopic aerial photographs in order to look for critical configurations once a critical mass has been detected its failure probability for a period of the order of one century must be evaluated or its life expectancy the main factor to consider for this purpose appears to be the proportion of rock bridges in the potential failure surface the triggering factors of rock falls in our study area have been investigated by analysing an inventory of 46 rock falls statistical tests have been carried out to study the relation between rock falls and daily rainfall freeze thaw cycles or earthquakes a good correlation has been obtained with freeze thaw cycles a slight correlation with rainfall and no correlation with earthquakes this suggests that ice jacking could the main physical process leading to failure by causing microcrack propagation

high mobility of rock ice avalanches insights from small flume tests of gravel ice mixtures rock ice avalanches in cold high mountain regions have extremely high mobility and enormous destructive potential as a special material component ice is supposed to play a crucial role in enhancing the mobility of rock ice avalanches a series of small flume tests was performed to quantify the influence of the ice content initial arrangement and released mass on the behavior and mobility of gravel ice mixtures and to provide insights into the propagation mechanisms of rock ice avalanches in their initial phase test results show that the run out distance and abrupt stopping distance increased significantly when the ice content reached 30 this implies that a certain amount of ice was helpful in enhancing the mobility of rock ice avalanches with an ice content higher than 80 the run out distances decreased slightly the run out distance in the well mixed case was greater than that in the layered arrangement cases segregation the phenomenon of ice cubes to tend toward the surface and front of the deposit was vital for the mobility of gravel ice mixtures segmentation was much more evident with an increase in ice content which indicates that the deposit was highly dispersed and spreading this was a key difference in the deposition morphology between cases of gravel ice mixture and cases of pure gravel or pure ice although little meltwater was generated in this study the development of intergranular water film and suction induced cohesion caused the particles to pack more closely together and to act as clusters rather than individual particles this study provides insights into the propagation mechanisms and deposition characteristics of rock ice avalanches

monsoon influenced variations in productivity and lithogenic flux along offshore saurashtra ne arabian sea during the holocene and younger dryas a multi proxy approach abstract a sediment core from ne arabian sea was studied to reveal the variations in shelf environment of western continental margin of india a multi proxy analysis based on planktonic foraminifera abundance pfa benthic foraminifera abundance bfa planktonic benthic foraminiferal ratio p b caco 3 percentage wt oxygen 18 o g ruber and carbon 18 o g ruber isotopes of foraminifera as well as sediment x ray studies were carried out on 3 4 m long core sk 240 485 recovered from offshore saurashtra ne arabian sea the study aims to understand the monsoon variability in the ne arabian sea offshore saurashtra since the late pleistocene holocene transition and how monsoon climate coupled with sea level change influenced paleo productivity pattern six ams radiocarbon dates place the core in the time interval 12 1 ka our study reveals that there have been three periods of major changes in the monsoonal climate productivity and sea level viz 12 8 ka younger dryas and early holocene 8 4 ka middle holocene and 4 1 ka late holocene the studied time period was also marked by weakened south west monsoon swm during the cold events such as younger dryas yd abrupt event ae centring around 9 8 ka as well as 8 2 and 4 ka cold events the younger dryas and early holocene shows the low sea level stand and less indus river discharge thereafter during middle and late holocene the monsoon strengthened which resulted in raised sea level and increased indus river discharge the proxy records broadly suggest relatively low foraminiferal productivity at the core location during the younger dryas and early holocene we record a moderate foraminiferal productivity during the middle holocene between 8 and 4 ka which suggest the mesotrophic condition the foraminiferal productivity however was relatively high since 4 ka suggesting the eutrophic conditions at the core site

a quantitative assessment of the genetic sources of the hydrologic flow regimes in upper indus basin and its significance in a changing climate summary reliable quantitative estimates of contributions melt water of different genetic sources make to river flows in himalayan river basins are largely unknown here we provide such estimates for upper indus basin uib analyses of historical flow records at 11 gauging stations spanning 14 48 years during a period of record from 1962 to 2010 reveal a uniform character of annual flow distributions at all gauging stations given by a gaussian function implying a unique glacio hydrometeorological condition prevailing throughout the basin controlling four hydrologic flow regimes within uib two low flow regimes occur during the months of october to december l1 and january to march l2 and two high flow regimes that occur during april june h1 and july september h2 for all stations flow magnitudes follow h2 h1 l1 l2 in the main stem of upper indus river the contributions to total annual flow volumes m 3 during these flow regimes are 53 62 during h2 24 32 during h1 8 9 during l1 and 4 6 during l2 in the main tributaries these ranges are 47 74 during h2 15 38 during h1 8 10 during l1 and 4 6 during l2 separation of annual hydrographs by linear smoothing and recursive digital filtering technique shows that the annual contribution of melt water m2 from an elevation band 3500 5300 m to total annual flow volume m 3 varies from 41 to 54 along the main stem of indus upstream of the himalayan foothills contribution of melt water m1 from an elevation band 2500 3500 m varies from 16 to 29 in the tributaries annual contributions of m2 vary from 37 to as high as 65 similarly annual contributions of m1 in the tributaries vary from as low as 12 to 34 thus the relative importance of melt water originating from high altitudes far overweighs that originating from mid altitudes in river runoff within uib the chief component of m1 is seasonal snows whereas m2 is a mixture of glacial melts seasonal snows falling in winter and spring and monsoonal snows falling in the summer july september the m2 component contributes to base flows during l1 regime base flow recession occurs during l2 regime during the h2 regime three watersheds with greatest glaciated surfaces straddling the karakoram mountains contribute 48 54 of flows at shatial bridge a point upstream of tarbela reservoir up to which rainfall contributions to river discharges in uib are inconsequential during the h1 regime these watersheds drained by shyok shigar and hunza rivers contribute 20 31 of flows at this point during l1 and l2 regimes their contributions are 33 39 and 31 32 respectively contributions of glacial melt and snowmelt to annual river flows vary from 18 35 and 38 50 respectively in the major tributaries and the main stem of upper indus depending on the location upper indus river just upstream of tarbela reservoir carries annual flows constituted of 70 melt water of which 21 is contributed by glacial melts and 49 by snowmelts thus changes in climatic trends will greatly control the future water availability within uib if glacial retreat and reduction of the perennial snow and ice covers are happening in uib in a changing climate then there will indeed be long term reductions in river flows in uib and hence sustainability of water resources in this basin will potentially be at risk

catastrophic detachment and high velocity long runout flow of kolka glacier caucasus mountains russia in 2002 abstract in september 2002 a catastrophic geomorphic event occurred in the caucasus mountains southern russia in which almost the entire mass of kolka glacier detached from its bed accelerated to a very high velocity max 65 80 m s and traveled a total distance of 19 km downstream as a glacier debris flow based on the interpretation of satellite imagery obtained only 8 5 h before the event occurred the analysis of seismograms from nearby seismic stations and subsequent detailed field observations and measurements we suggest that this remarkable event was not a response to impulse loading from a rock avalanche in the mountainside above the glacier or to glacier surging but due entirely to the static and delayed catastrophic response of the kolka glacier to ice and debris loading over a period of months prior to the september 20 detachment we reconstruct the glacier debris flow using field observations in conjunction with the interpretation of seismographs from nearby seismic stations and successfully simulate the behaviour runout velocity and deposition of the post detachment glacier debris flow using a three dimensional analytical model our demonstration of a standing start hypothesis in the 2002 kolka glacier detachment has substantial implications for glacier hazard assessment and risk management strategies in valleys downstream from unstable debris covered glaciers in the mountain regions of the world

integrated monitoring of mountain glaciers as key indicators of global climate change the european alps the internationally recommended multi level strategy for monitoring mountain glaciers is illustrated using the example of the european alps where especially dense information has been available through historical times this strategy combines in situ measurements mass balance length change with remote sensing inventories and numerical modelling it helps to bridge the gap between detailed local process oriented studies and global coverage since the 1980s mass balances have become increasingly negative with values close to 1 m w e a 1 during the first 5 years of the 21st century the hot dry summer of 2003 alone caused a record mean loss of 2 45 m w e roughly 50 above the previous record loss in 1998 more than three times the average between 1980 and 2000 and an order of magnitude more than characteristic long term averages since the end of the little ice age and other extended periods of glacier shrinkage during the past 2000 years it can be estimated that glaciers in the european alps lost about half their total volume roughly 0 5 a 1 between 1850 and around 1975 another 25 or 1 a 1 of the remaining amount between 1975 and 2000 and an additional 10 15 or 2 3 a 1 in the first 5 years of this century

evaluating titan2d mass flow model using the 1963 little tahoma peak avalanches mount rainier washington the titan2d geophysical mass flow model is evaluated by comparing its simulation results and those obtained from another flow model flow3d with published data on the 1963 little tahoma peak avalanches on mount rainier washington the avalanches totaling approximately 10 10 6 m 3 of broken lava blocks and other debris traveled 6 8 km horizontally and fell 1 8 km vertically h l 0 246 velocities calculated from runup range from 24 to 42 m s and may have been as high as 130 m s while the avalanches passed over emmons glacier titan2d is a code for an incompressible coulomb continuum it is a depth averaged dshallow watert granular flow model the conservation equations for mass and momentum are solved with a coulomb type friction term at the basal interface the governing equations are solved on multiple processors using a parallel adaptive mesh godunov scheme adaptive gridding dynamically concentrates computing power in regions of special interest mesh refinement and coarsening key on the perimeter of the moving avalanche the model flow initiates as a pile defined as an ellipsoid by a height z and an elliptical base defined by radii in the x and y planes flow parameters are the internal friction angle and bed friction angle results from the model are similar in terms of velocity history lateral spreading location of runup areas and final distribution of the little tahoma peak deposit the avalanches passed over the emmons glacier along their upper flow paths but lower in the valley they traversed stream gravels and glacial outwash deposits this presents difficulty in assigning an appropriate bed friction angle for the entire deposit incorporation of variable bed friction angles into the model using gis will help to resolve this issue d 2004 elsevier b v all rights reserved

estimating the timing and location of shallow rainfall induced landslides using a model for transient unsaturated infiltration 1 shallow rainfall induced landslides commonly occur under conditions of transient infiltration into initially unsaturated soils in an effort to predict the timing and location of such landslides we developed a model of the infiltration process using a two layer system that consists of an unsaturated zone above a saturated zone and implemented this model in a geographic information system gis framework the model links analytical solutions for transient unsaturated vertical infiltration above the water table to pressure diffusion solutions for pressure changes below the water table the solutions are coupled through a transient water table that rises as water accumulates at the base of the unsaturated zone this scheme though limited to simplified soil water characteristics and moist initial conditions greatly improves computational efficiency over numerical models in spatially distributed modeling applications pore pressures computed by these coupled models are subsequently used in one dimensional slope stability computations to estimate the timing and locations of slope failures applied over a digital landscape near seattle washington for an hourly rainfall history known to trigger shallow landslides the model computes a factor of safety for each grid cell at any time during a rainstorm the unsaturated layer attenuates and delays the rainfall induced pore pressure response of the model at depth consistent with observations at an instrumented hillside near edmonds washington this attenuation results in realistic estimates of timing for the onset of slope instability 7 h earlier than observed landslides on average by considering the spatial distribution of physical properties the model predicts the primary source areas of landslides

unraveling driving factors for large rock ice avalanche mobility large rock ice avalanches have attracted attention from scientists for decades and some of these events have caused high numbers of fatalities a relation between rock slope instabilities in cold high mountain areas and climate change is currently becoming more evident and questions about possible consequences and hazard scenarios in densely populated high mountain regions leading beyond historical precedence are rising to improve hazard assessment of potential rock ice avalanches their mobility is a critical factor this contribution is an attempt to unravel driving factors for the mobility of large rock ice avalanches by synthesizing results from physical laboratory experiments and empirical data from 64 rock ice avalanches with volumes 1x106 m3 from glacierized high mountain regions around the world the influence of avalanche volume water and ice content low friction surfaces and topography on the apparent coefficient of friction as a measure of mobility is assessed in laboratory experiments granular ice in the moving mass was found to reduce bulk friction up to 20 while water led to a reduction around 50 for completely saturated material compared with dry flows evidence for the effects of water as a key driving factor to enhance mobility was also found in the empirical data while the influence of the ice content could not be confirmed to be of much relevance in nature besides liquefaction it was confirmed that mobility increases with volumes and that frictional surface characteristics such as flow paths over glaciers are also dominant variables determining mass movement mobility effects of the topography along the flow path as well as channeling are assumed to be other critical factors the results provide an empirical basis to roughly account for different path and flow characteristics of large rock ice avalanches and to find appropriate ranges for friction parameters for scenario modeling and hazard assessments copyright 2011 john wiley sons ltd

a model for frictional melt production beneath large rock avalanches 1 two puzzling traits of giant rock avalanches sturzstroms are the decrease of the effective friction coefficient as a function of the volume volume effect and the remarkable preservation of large geological structures during the flow demonstrating that the upper cap of a sturzstrom travels coherently on top of a basal shear layer hence frictional heat is rapidly produced along the shear layer which could explain the formation of sheets of molten rock inside certain landslide deposits it has been conjectured that a molten layer could potentially self lubricate the base of the sturzstrom to theoretically investigate this scenario we consider the model of a rock slab sliding on an inclined surface we present a set of coupled differential equations to calculate the frictional heat produced the properties of the molten layer thickness temperature and velocity distribution and the motion of the slab our simulations illustrate the onset of self lubrication and show the volume effect when the melt viscosity is low corresponding to a simulated mafic composition of the rock for a felsic composition and to some extent also for intermediate melts we find that the melting introduces more resistance at the beginning of the melting process in close similarity with frictional melting in tectonic faults however in contrast to faults the rock avalanche is capable of overcoming the initial resistance in at least two situations if the rock is rigid and the landslide is sufficiently thick or else if the material of the landslide is disintegrated the simulations also show that although self lubrication is a viable possibility to explain the runout of sturzstroms there are rather stringent conditions for the formation of a molten layer of good lubricating qualities more generally we suggest that the properties of the coulomb frictional law at the interfaces may change radically during sliding and that the assumption of constant friction does not represent a good model in landslide calculations

tributary glacier surges an exceptional concentration at panmah glacier karakoram himalaya four tributaries of panmah glacier have surged in less than a decade three in quick succession between 2001 and 2005 since 1985 13 surges have been recorded in the karakoram himalaya more than in any comparable period since the 1850s ten were tributary surges in these ten a full run out of surge ice is prevented but extended post surge episodes affect the tributary and main glacier the sudden concentration of events at panmah glacier is without precedent and at odds with known surge intervals for the glaciers interpretations must consider the response of thermally complex glaciers at exceptionally high altitudes and of high relief to changes in a distinctive regional climate it is suggested that high altitude warming affecting snow and glacier thermal regimes or bringing intense short term melting episodes may be more significant than mass balance change

signature and hydrologic consequences of climate change within the upper middle brahmaputra basin a prevailing perception is that the glaciers and perennial snow and ice covered areas scap or in the himalayan region are fast contracting however systematic studies providing the quantitative estimates of scap as a function of time within individual river basins are lacking the importance of meltwater in river flows varies greatly from one river basin to another yet the actual estimates of those contributions are largely unknown this study bridges such knowledge gaps for the upper middle brahmaputra basin by using best available digital cartographic and remotely sensed snow cover data we find that when the entire basin is considered scap decreased from 7637 764 in 1980 to 4298 1422 km2 in 1992 however it has increased to 7160 2248 km2 in 2000 from 2000 to 2010 the scap has remained nearly constant around a mean of 10 052 1468 km2 the same trend is observed within individual physiographic zones of the basin such increase in scap is due to the increase in the precipitation over the middle brahmaputra basin and the nyainquentanglha mountains as observed in station records the incursion of moist air through the brahmaputra valley to the higher elevations within the nyainquentanglha mountains causes snowfall during pre monsoonal and post monsoonal seasons and an expansion of the scap glacial expansions in the nyainquentanglha mountains have also been observed in other recent studies in addition to the increase in precipitation and scap another manifestation of climate change observed in this basin is the increasing temperature with a mean annual trend of 0 28 c decade the hydrologic consequences of the observed effects of climate change are expected to be an insignificant change in streamflows in the watersheds drained by the upper brahmaputra river but a perceptible increase in river discharges in the watersheds drained by the middle brahmaputra river and its tributaries particularly within the upper and lower catchments of the middle brahmaputra basin copyright 2012 john wiley sons ltd