new insights into the 1963 vajont slide using 2d and 3d distinct element method analyses the 1963 vajont rock slide is studied using the distinct element method dem two dimensional 2d and three dimensional 3d dem models were constructed based on information published in the literature in this study a strength reduction approach was used to calculate the slide surface friction angles required for stability the influence of several parameters was investigated in 2d namely the reservoir water level the shear stiffness of the slide surface the rock mass strength the rock mass deformability and rock joint patterns of the parameters which have been investigated the most important parameter was found to be the reservoir water level the rock mass deformability which is neglected by other investigators is also found to be important from the 3d analyses the failure friction angle was found to be sensitive to the assumptions made on the eastern boundary and could affect the failure friction angle by approximately 3 the slope was found to exhibit signs of failure beginning from s

further evidence for a mass movement origin of the olympus mons aureole analysis of the ridge graben and fracture patterns on the aureole material surrounding olympus mons lends further support to an origin by gravity sliding of the outer flanks of the shield the patterns provide evidence of the nature of sliding especially in the last stages of emplacement no part of the slide need have traveled the whole extent of the aureole for the slides to occur on a shallow slope reduction of shear strength of the materials involved is required possibly by melting of ground ice triggering mechanisms could be volcanically related marsquakes and possibly stresses induced on the surrounding area by the growing olympus mons volcano

a linear regression framework for predicting subsurface geometries and displacement rates in deep seated slow moving landslides abstract a new numerical integration linear regression tool is used to investigate kinematic behavior in deep seated sliding surface deeper than 3 m mass movements the technique is developed in the context of real inclinometer records and numerical integration using nine inclinometer case histories from four well documented large landslides carrot river montebestia karya village and pietrapertosa axial metric subsurface geometric deformation rates are predicted and compared for four different case studies from the literature a reactivated composite extremely slow earth slide earthflow a reactivated composite extremely slow debris slide rock fall an active composite very slow earth slide earth flow and a reactivated complex slow earth slide earth spread sensitivity analysis based on sliding surface depth to length d l ratios show that the mobility of these slow moving masses is closely dependent on the mode of sliding the results also show that short term and long term dynamics of slow moving landslides can be captured by geometrical patterns because the parameter determined is a geometric property the technique used in the investigation can be applied in new landslide problems independent of local conditions and triggering mechanisms within the confines of the stipulated boundary conditions hence with this framework also unrelated landslide problems can be analyzed and compared as demonstrated herein additionally this approach is useful for two dimensional reconstructions of subsurface displacement and velocity profiles and thus may act as a precursor to detailed field investigation programs warning systems and mitigation projects at minimal costs

a kinematic method for calculating shear displacements of landslides using distributed fiber optic strain measurements abstract deformation monitoring of landslides is of great significance to characterize and understand their evolutions recently the distributed fiber optic strain sensing dfoss technique has emerged as a powerful tool for landslide monitoring by enabling distributed and real time measurement along a sensing optical fiber sof over dozens of kilometers with high strain accuracy however the correlation between landslide displacements and axial strains exerted on an sof remains elusive here we present a preliminary attempt to calculate shear displacements of landslides based on distributed strain measurements via a kinematic method parametric studies on the sliding direction width of shear zone and magnitude of shear displacement indicate that under certain circumstances the shear displacements of a landslide can be well estimated without going much deep into the pattern of shear zone or the slope mass sof coupling condition the proposed calculation method is validated through field shear tests of geologic granular materials and has immediate application to the analysis of the majiagou landslide three gorges reservoir region china the distributed strain measurements captured by a borehole embedded sof allow two sliding surfaces of this landslide to be located one occurred at the contact between surface deposits and bedrock whereas the other was the main sliding surface occurring within bedrock the shear displacements along the main sliding surface are calculated using the proposed method it is revealed that the landslide responds more aggressively to the fluctuation of reservoir water level than to the rainfall over a 1 year period

ring shear tests on soil from the vaiont landslide slip surface the paper presents results from ring shear tests carried out on two samples from the slip surface of the vaiont landslide in north italy the tests were carried out at slow and fast rates of shearing in order to determine values of the coefficient of friction appropriate to static and dynamic aspects of the landslide both samples showed a significant loss of strength negative rate effect up to 60 below the slow residual strength when sheared at rates of shearing greater than 100 mm min the observed loss of strength may explain the high acquired velocity of the landslide or alternatively some combination of this and other mechanisms may have taken place le papier presente les resultats d essais de cisaillement par anneau effectues sur deux echantilions preleves sur la surface de cisaillement du glissement de terrain vaiont dans le nord de l italie les essais ont ete menes avec des vitesses de cisaillement lentes et rapides de maniere a pouvoir determiner les valeurs des coefficients de frotteme

forecasting volcanic events some contemporary issues as the regions around active volcanoes succumb to large increases in population particularly in the developing world where most of the high risk volcanoes are located the threat posed by eruptions becomes increasingly serious improvements in eruption forecasting are critical to combat this situation for reducing injury and loss of life and for minimizing the detrimental effects to local economies and to the fabric of society better constrained forecasts are strongly dependent on geophysical and other data gathered during a program of volcano surveillance and we reveal how if interpreted in terms of static rock fracturing analysis of changes in volcanic seismicity and ground deformation may be used to forecast more accurately the onset of eruptive activity as illustrated by recent events at several volcanoes studies of previous activity increased levels of monitoring and improved training of scientists are also all crucial to improving forecasts of impending eruptions

the use of surface monitoring data for the interpretation of landslide movement patterns the tessina landslide is a large seasonally active slope failure located on the southern slopes of mt teverone in the alpago valley of ne italy consisting of a complex system that has developed in tertiary flysch deposits the landslide which first became active in 1960 threatens two villages and is hence subject to detailed monitoring with high quality data being collected using piezometers inclinometers extensometers and through the use of a highly innovative automated electronic distance measurement edm system which surveys the location of a large number of reflector targets once every 6 h these systems form the basis of a warning system that protects the villages but they also provide a very valuable insight into the patterns of movement of the landslide in this paper analysis is presented of the movement of the landslide concentrating on the edm dataset which provides a remarkable record of surface displacement patterns it is proposed that four distinct movement patterns can be established which correspond closely to independently defined morphological assessments of the landslide complex any given block of material transitions through the four phases of movement as it progresses down the landslide with the style of movement being controlled primarily by the groundwater conditions the analysis is augmented with modelling of the landslide undertaken using the itasca flac code the modelling suggests that different landslide patterns are observed for different parts of the landslide primarily as a result of variations in the groundwater conditions the model suggests that when a movement event occurs displacements occur initially at the toe of the landslide then retrogress upslope

forecasting giant catastrophic slope collapse lessons from vajont northern italy rapid giant landslides or sturzstroms are among the most powerful natural hazards on earth they have minimum volumes of similar to10 6 10 7 m 3 and normally preceded by prolonged intervals of accelerating creep are produced by catastrophic and deep seated slope collapse loads similar to1 10 mpa conventional analyses attribute rapid collapse to unusual mechanisms such as the vaporization of ground water during sliding here catastrophic collapse is related to self accelerating rock fracture common in crustal rocks at loads similar to1 10 mpa and readily catalysed by circulating fluids fracturing produces an abrupt drop in resisting stress measured stress drops in crustal rock account for minimum sturzstrom volumes and rapid collapse accelerations fracturing also provides a physical basis for quantitatively forecasting catastrophic slope failure c 2003 elsevier science b v all rights reserved

climate forcing of volcano lateral collapse evidence from mount etna sicily in this study we present evidence for early holocene climatic conditions providing circumstances favourable to major lateral collapse at mount etna sicily the volcano s most notable topographic feature is the valle del bove a 5 x 8 km cliff bounded amphitheatre excavated from the eastern flank of the volcano its origin due to prehistoric lateral collapse is corroborated by sturtzstrom deposits adjacent to the amphitheatre s downslope outlet but the age nature and cause of amphitheatre excavation remain matters for debate cosmogenic 3 he exposure ages determined for eroded surfaces within an abandoned watershed flanking the valle del bove support channel abandonment ca 7 5 ka bp as a consequence of its excavation in a catastrophic collapse event watershed development was largely dictated by pluvial conditions during the early holocene which are also implicated in slope failure a viable trigger is magma emplacement into rift zones in the eastern flank of a water saturated edifice leading to the development of excess pore pressures consequent reduction in sliding resistance detachment and collapse such a mechanism is presented as one potential driver of future lateral collapse in volcanic landscapes forecast to experience increased precipitation or melting of ice cover as a consequence of anthropogenic warming

deep seated gravitational deformation of mountain slopes caused by river incision in the central range taiwan spatial distribution and geological characteristics abstract fluvial undercutting can cause the large scale destabilization of mountain slopes and induce deep seated gravitational slope deformation dgsd that eventually leads to catastrophic failures this study analyses these processes in the catchment of the dahan river northern taiwan the area has experienced phases of river incision of up to 600 m since the middle to late pleistocene and middle pleistocene paleosurfaces at higher elevations were incised to form v shaped valleys a dgsd inventory was compiled by visual interpretation of high resolution images and field surveys were conducted to clarify the geological structures associated with dgsds and major rockslide avalanches the observed relationships between dgsds and the topography modified by long term river incision show that about 53 of all dgsds occurred on slopes along the rims of paleosurfaces which is approximately 2 and 2 5 times as many as in the incised valleys and on the paleosurfaces respectively a comparison of the power law scaling exponents of cumulative frequency area distributions shows that the frequency of dgsds along the rims of the paleosurfaces decreases less rapidly with dgsd area than for dgsds on other slopes geological investigations suggest that there are two dominant types of dgsd one is flexural toppling of slate and argillite with high angle cleavage and the other is buckling of alternating beds of sandstone and mudstone on parallel or underdip cataclinal slopes catastrophic landslides observed along or below the rims of paleosurfaces were preceded by buckling of alternating beds of sandstone and shale these beds dipped at 50 to 58 and each bed was 10 1 10 0 m thick this study suggests that the peripheral zones of the paleosurfaces may be most susceptible to future catastrophic landslides particularly on parallel or underdip cataclinal slopes comprising alternating beds of sandstone and mudstone dipping at 50 to 60 thus an understanding of the geological characteristics spatial distribution of dgsd occurrence and landscape evolution within a particular area can provide important information for landslide hazard level zoning

geomorphological and sedimentological evolution of a lake basin under strong volcano tectonic influence the seismic record of lago calafquen south central chile the chilean lake district is a geodynamically active area located at the foot of the andean cordillera and permanently influenced by the chilean active continental margin the study area is prone to steady mass movements that are triggered by active volcanism strong earthquakes and climatic forces on the glacial born lake lago calafquen high resolution seismic investigation was performed to select suitable coring sites for sedimentary analyses to revise the existing bathymetry and to integrate the lake bottom topography into the geomorphological context of the surroundings the sub bottom profiling reveals a complex structure of the lake floor which results in a division into an eastern and a central sub basin the eastern basin encompasses the deep basin plain which is a depositional area for dense suspension loaded underflows the morphology of the basement of the central sub basin is affected by large landslides large rock slope failures of debuttressed sidewalls fill the primary lake floor of the southern side covered by more than 40 m of sediment a high resolution seismic analysis of the sedimentary infill reveals deposits and structures of large mass movements and turbidites obviously triggered by strong earthquakes incidents related to rebound effects by isostatic uplift are also considered to provoke remarkable magnitudes that trigger mass movement processes in the central sub basin furthermore volcanic impact frequently interrupts normal lacustrine sedimentation of the sediment succession by deposition of tephra layers the serialized geodynamic impacts on lago calafquen cause severe damage to the sedimentary archive thus suitable coring sites for palaeoenvironmental reconstruction should be selected carefully

the mechanics of deep seated landslides results are presented of a sequence of laboratory tests undertaken to elucidate the behaviour of deep seated landslides in deep seated failures deformation has been reported at depths of up to 250 m in the movement zone owing to the weight of the overburden and the surrounding stress environment conventional soil mechanics cannot be used to explain effectively associations between the landslip activity and the deformation mechanisms operating within the moving mass a series of experiments has been undertaken on london clay using a high pressure servohydraulically controlled triaxial deformation system to replicate the stresses acting at the base of a large deep seated landslide a number of tests were undertaken the most significant focusing on the transition between ductile and brittle behaviour although sediments usually behave in a brittle manner at low effective stresses common to many geomorphological studies and in a ductile manner at high effective stresses the results presented here identify for the first time in mudrocks a transitional phase of behaviour in which creep like movement will manifest itself at the base of a deep seated landslide as the growth of microcracks the microcracks may eventually coalesce to form a shear surface a consequence of which is likely to be sudden failure the results thus have important implications in the understanding of movement mechanisms in large deep seated failures rates of displacement and how they may change through time 1997 by john wiley sons ltd

analysis of seismic driven instability of mt nuovo in the ischia island italy abstract ischia is a volcanic island located at the margin of the gulf of naples in the southeastern tyrrhenian sea italy in this article we investigate the stability of the deep seated block known as mt nuovo in the northwestern flank of the mt epomeo volcano under a combined gravitational and seismic load mt nuovo is bounded by a number of active seismic faults and is placed close to the epicentral area of the 1883 casamicciola earthquake i mcs x m w 5 8 that is the largest shock occurring in the island in historical times we explore the hypothesis that a casamicciola like earthquake might occur with an epicenter in the mt nuovo block area using relationships between maximum seismic intensity and peak ground acceleration found in the literature as well as a new relationship derived specifically for this study we apply the minimum lithostatic deviation method which is a variant of the limit equilibrium method to assess the stability of the block the main finding is that mt nuovo would be mobilized if such an earthquake took place on a fault very close to the block which would give rise to a catastrophic mass failure and to a disastrous tsunami this calls for the need of continuous monitoring of the volcano seismicity and deformation pattern

influence of filling drawdown cycles of the vajont reservoir on mt toc slope stability abstract in the present work the 1963 vajont landslide has been back analyzed in detail to examine the influence of reservoir operations filling and drawdown on mt toc slope stability the combined seepage slope stability analyses carried out show that the main destabilizing factor that favored the 1963 vajont landslide was the reservoir induced water table that formed as a consequence of rapid seepage inflow within the submerged toe of the slope decrease in the factor of safety fos up to 12 compared to the initial slope stability condition i e in the absence of the vajont reservoir rainfall would only have been a decisive factor if the initial stability condition of the mt toc slope had already been very close to failure decrease in fos caused by heavy or prolonged rainfall is about 3 4 for the worst case scenario analyzed the permeability of the shear zone material occurring at the base of the prehistoric vajont rockslide has been evaluated at 5 10 4 m s and back calculated values of the friction angles range from 17 5 to 27 5 when considering mountain reservoirs slope failures can occur during both filling and drawdown phases in the vajont case owing to the highly permeable materials of the shear zone slope stability decreased during filling and increased during drawdown another displacement dependent phenomenon of a mechanical nature progressive failure of the ne landslide constraint has to be considered to understand the slope collapse that occurred during the last drawdown 26 september 9 october 1963 the results of the combined seepage slope stability models indicate that permeability of bank forming material and filling drawdown rates of reservoirs can strongly influence slope stability slow lowering of the reservoir level is a necessary measure to reduce the occurrence of very dangerous transient negative peaks of fos

the role of the spatial scale and data accuracy on deep seated gravitational slope deformation modeling the ronco landslide italy abstract in recent decades numerical models have been developed and extensively used for landslide hazard and risk assessment the reliability of the outcomes of these numerical simulations must be evaluated carefully as it mainly depends on the soundness of the physical model of the landslide that in turn often requires the integration of several surface and subsurface surveys in order to achieve a satisfactory spatial resolution merging diverse sources of data may be particularly complex for large landslides because of intrinsic heterogeneity and possible great data uncertainty in this paper we assess the spatial scale and data accuracy required for effective numerical landslide modeling we focus on two particular aspects the model extent and the accuracy of input datasets the ronco landslide a deep seated gravitational slope deformation dsgsd located in the north of italy was used as a test bed geological geomorphological and geophysical data were combined and as a result eight models with different spatial scales and data accuracies were obtained the models were used to run a back analysis of an event in 2002 during which part of the slope moved after intense rainfalls the results point to the key role of a proper geomorphological zonation to properly set the model extent the accuracy level of the input datasets should also be tuned we suggest applying the approach presented here to other dsgsds with different geological and geomorphological settings to test the reliability of our findings

yield estimation using bandpass filtered seismograms preliminary results using neural networks with mb pn short time long time and coda energy measurements abstract a neural network has been developed to simultaneously use multiple seismic measurements such as m b pn and coda energy for estimating yields of underground nuclear explosions yield estimation results based on a large number of nevada test site events that were recorded at the broadband seismic stations at elko kanab landers and mina indicate that different length windows 6 18 and 200 sec of seismogram energy are as useful as the m b pn measurement when the seismogram is filtered between 0 5 and 2 hz detailed results of yield estimation trends as a function of signal frequency are also obtained yield estimation performance using long lapse time coda energy above 2 hz is significantly limited by the signal to noise ratio snr performance of the neural network with both m b pn and energy information as input does not significantly exceed the performance of a conventional linear regression analysis that is based only on m b pn properties of the coda signal as a function of frequency and snr that might ultimately lead us to the application of a full seismogram with a neural network for accurate seismic yield estimation are discussed

reinforcement effects and safety monitoring index for high steep slopes a case study in china abstract high and steep slopes which have developed fractures and intercalations are a great threat to the operation of dams and reservoirs in this work the geological conditions and potential modes of failure of the slope found in the right bank of suofengying hydropower station are investigated for the slope stability and the results are presented in order to strengthen the slope an innovative stabilization scheme is employed the stabilization techniques include development of anti shear tunnels anti slide piles anchor cables concrete support structure etc further the slope stability and reinforcement effects using various stabilization techniques are studied by using finite element strength reduction method moreover in situ monitoring is carried out and the data obtained is analyzed from the results it is observed that the deformations that are detected using multipoint extensometers have decreased after the installation of remedial reinforcements from the analysis of remedial reinforcement methods it is found that the most critical reinforcement is the development of anti shear tunnels in order to monitor the stresses in stirrups and the propagation of cracks in the anti shear tunnels three levels of safety monitoring index are proposed the safety monitoring index is developed based on the results obtained by the simulation of the process of failure of the reinforced slope the developed safety monitoring index is further applied to the suofengying project in order to evaluate the overall stability of the slope the results obtained by monitoring indicate that the performance of the reinforcement structures is satisfactory and the slope has better stability the methodology proposed in this work shall be useful for similar projects to obtain stability of slopes

thermoporomechanics of creeping landslides the 1963 vaiont slide northern italy 1 the catastrophic vaiont landslide southern alps italy of 9 october 1963 moved 2 7 108 m3 of rock that collapsed in an artificial lake causing a giant wave that killed 1917 people the landslide was preceded by 2 3 years of creep that ended with the final collapse of the rock mass slipping at about 30 m s 1 assuming that creep was localized in a clay rich water saturated layer in this study we propose shear heating as the primary mechanism for the long term phase of accelerating creep we study only the creeping phase of the slide and we model this phase using a rigid block moving over a thin zone of high shear strain rates introducing a thermal softening and velocity strengthening law for the basal material we reformulate the governing equations of a water saturated porous material obtaining an estimate for the collapse time of the slide our model is calibrated upon real velocity measurements from the vaiont landslide and provides an estimation of the critical time of failure up to 169 days before the collapse we also show that the slide became critical 21 days before the collapse when shear heating started localizing in the clay rich layer inducing a tendency for slip localization and thermal runaway instability in a plane the total loss of strength in the slipping zone during the last minutes prior to the slide is explained by the onset of thermal pressurization triggered by the temperature rise within the clay rich layer

susceptibility of reservoir induced landslides and strategies for increasing the slope stability in the three gorges reservoir area zigui basin as an example abstract the construction of the huge three gorges reservoir affected a large region and the resultant geological and environmental impacts have caused global concern the remarkable 30 m annual fluctuation in the reservoir water level poses a significant threat to slope stability in this area four hundred sixty two landslides were identified in the zigui basin using historical records satellite images field investigations and unmanned aerial vehicle uav observations enabling the construction of a complete landslide database and distribution map three failure modes of landslides in the zigui basin are used to illustrate the major factors that govern reservoir induced landslides the results show that 1 99 of identified landslides occur on slopes angle 80 occur at elevations below 600 m 2 jurassic niejiashan formation is highly prone to landslides 3 low reservoir levels of 145 m to 155 m greatly reduce slope stability based on the information entropy method that use the conditional probability of different influencing factors and principal component analysis as inputs the relative contributions of various influencing factors are quantified and a landslide susceptibility map was drawn this susceptibility map helps define the countermeasures that will best reduce fatalities and property losses for areas having different landslide conditions and susceptibilities

an accelerating precursor to predict time to failure in creep and volcanic eruptions real time prediction by monitoring of the evolution of response variables is a central goal in predicting rock failure a linear relation omega omega similar to 1 c t f t has been developed to describe the time to failure where li represents a response quantity c is a constant and tf represents the failure time observations from laboratory creep failure experiments and precursors to volcanic eruptions are used to test the validity of the approach both cumulative and simple moving window techniques are developed to perform predictions and to illustrate the effects of data selection on the results laboratory creep failure experiments on granites show that the linear relation works well during the final approach to failure for blind prediction the simple moving window technique is preferred because it always uses the most recent data and excludes effects of early data deviating significantly from the predicted trend when the predicted results show only small fluctuations failure is imminent c 2017 elsevier b v all rights reserved

low to high velocity frictional properties of the clay rich gouges from the slipping zone of the 1963 vaiont slide northern italy the final slip of about 450 m at about 30 m s of the 1963 vaiont landslide italy was preceded by 3 year long creeping phase which was localized in centimeter thick clay rich layers 60 70 smectites 20 30 calcite and quartz here we investigate the frictional properties of the clay rich layers under similar deformation conditions as during the landslide 1 5 mpa normal stress 2 10 7 to 1 31 m s slip rate and displacements up to 34 m experiments were performed at room humidity and wet conditions with biaxial torsion and rotary shear apparatus the clay rich gouge was velocity independent to velocity weakening in both room humidity and wet conditions in room humidity experiments the coefficient of friction decreased from 0 47 at v 0 70 m s full lubrication results from the formation of a continuous water film in the gouge the vaiont landslide occurred under wet to saturated conditions the unstable behavior of the landslide is explained by the velocity weakening behavior of the vaiont clay rich gouges the formation of a continuous film of liquid water in the slipping zone reduced the coefficient of friction to almost zero even without invoking the activation of thermal pressurization this explains the extraordinary high velocity achieved by the slide during the final collapse

multi stage structural and kinematic analysis of a retrogressive rock slope instability complex preonzo switzerland abstract large catastrophic rock slope failures are difficult to predict because the underlying mechanisms causing slope accelerations are difficult to study under in situ conditions for slope failures with compound basal rupture planes not only fracture propagation and slip in the basal rupture surface but also within the landslide body control the displacement evolution and time to failure the preonzo instability complex in southern switzerland failed several times since 2002 and offers a unique opportunity to study these mechanisms under in situ conditions the largest failure at preonzo occurred in may 2012 and was conditioned by large slope parallel nne ssw fracture zones which are intersected by ne and sw and e w striking faults creating diverging lateral boundaries whereas in the head scarp region oblique and flexural toppling along pre existing fracture sets is the prevailing mechanism sliding of either planar or wedge type is the preferred kinematic mode facilitated by the new discontinuities developed within the basal rupture surfaces these dominating mechanisms leading to a classical rock slope collapse could only be revealed in retrospect we compare fracture patterns in stable ground tectonic and unloading fractures with new fractures related to rock slope failure observed on basal rupture surfaces and in the head scarp simplified mechanical and kinematic analyses show that old pre existing tectonic fractures cannot accommodate substantial deformations under the in situ stress conditions and propagate connect through curved wing cracks forming at high angles this situation favors the development of new nearly slope parallel fractures which are interpreted as synthetic p shears along localized shear zones fractographic markings on these fractures indicate a continuous and relatively fast formation which presumably has taken place during a period of about 60 years prior to catastrophic failure this detailed description of the multi stage evolution of slope failure at preonzo represents a unique data set for future numerical studies of progressive failure in crystalline rocks

runout lengths of sturzstroms the control of initial conditions and of fragment dynamics sturzstroms are giant landslides that travel kilometers within minutes data from terrestrial examples of 0 001 10 km3 suggest that their runout lengths increase in proportion to the square root of their volume this trend is investigated assuming that runout is controlled by fragmental flow the results indicate that runout lengths depend on the potential energy available for motion after initial collapse itself a function of the dimensions of the collapse zone on the degree of rock fragmentation and on the rate of momentum loss by fragment collisions in a basal boundary layer assumed to thicken with time by diffusion a dependence on initial conditions during collapse would explain claims that a minimum volume is required for sturzstroms to form beneath a critical volume insufficient energy is available to initiate fragmental flow and so the unstable mass slumps downslope the drop height h is often similar to the vertical extent of the collapse zone and so is linked by geometry to sturzstrom volume the ratio of h to l the horizontal distance of effective transport normally interpreted as a measure of frictional resistance is thus reinterpreted as an inverse measure of the energy available for runout after collapse by providing a physical basis for observed trends the analysis justifies use of empirical limits for forecasting the runout lengths of major landslides

timing and features of a late mis 2 rock avalanche in the eastern himalayas constrained by 10be exposure dating abstract we investigate a previously unrecorded rock avalanche deposit yadong rock avalanche that resulted from a major mountain slope failure on the northwest slopes of mt chomo lhari in the eastern himalayas we provide detailed mapping of the yadong rock avalanche and date the rock avalanche using 10be surface exposure dating the 10be exposure ages of six samples suggest that the yadong rock avalanche occurred between 14 2 1 3 13 1 1 3 ka during the bolling allerod ba period the climate was semi arid during the ba period as it is today which suggests that precipitation was unlikely the trigger for this rock avalanche the relatively small paleo glaciers make glacial debuttressing trigger unlikely since the rock scar is situated above the lower permafrost limit degradation of permafrost associated with deglaciation was also unlikely to be the trigger given the rock avalanche is located near the yadong fault which is part of the active yadong gulu rift and the yadong gulu rift has experienced great earthquakes on centennial to millennial timescales we suggest that the most probable trigger for this rock avalanche was a seismic event associated with the yadong fault the result provides evidence for identifying a paleo seismic event occurred during 14 2 1 3 13 1 1 3 ka these findings have important implications for understanding the mechanisms for driving rock avalanches and associated landscape evolution across the himalayas as well as for extending the limited scientifically documented records of major mass movements in the eastern himalayan region

september 2005 rain induced catastrophic rockslides on slopes affected by deep seated gravitational deformations kyushu southern japan river rejuvenation forms convex slope breaks that can destabilize nearby slopes leading to gravitational deformation and in some cases catastrophic sliding of the slopes during heavy rainstorms such landslides were induced by typhoon 0514 which passed to the west of kyushu island japan on 6 september 2005 five large catastrophic rockslides occurred aligning along convex slope breaks 150 to 300 m above the present river bed of the mimi river the slope breaks are inferred to have been formed by rejuvenation of the river geological and geomorphological investigation revealed that these slides occurred in sandstone and mudstone of the cretaceous shimanto group and were preceded by slope deformation which generated gravitational folds and faults that appeared as scarplets at the tops of the deformed areas the slopes seem to have been in critical condition just before catastrophic failure which was triggered by the rainstorm

insights from analogue modelling into the deformation mechanism of the vaiont landslide abstract the vaiont landslide southern alps italy represents one of the most catastrophic landslides in the world recorded in the modern history the landslide occurred on 9th october 1963 involved about 3 10 8 m 3 of rock that collapsed in an artificial lake more than 1900 people died as a consequence of the tsunami produced by the sudden fall of the mass in the water despite the importance of this event many aspects of the vaiont rockslide still remain unexplained particularly its fast emplacement in order to obtain a better understanding of the vaiont disaster this paper focuses on the results of analogue models designed to get insights into the internal and surficial deformation patterns that characterized the sliding rock mass plan view reconstructions of surface model displacement reveal that the rock mass is subdivided into compartments with different relative movements and differential rotations believed to have played a significant role in causing the fast collapse the deformation of the analogue models compared with geological cross sections and in situ data suggests that sliding of the rock mass was accomplished by the development of some new or the reactivation of pre existing fractures into the rock mass