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

influence of kinematics on landslide mobility and failure mode geometry of discontinuities greatly influences the kinematic behavior of slopes and landslides discontinuous deformation analysis dda is used here to analyze two typical examples of slope failure demonstrating that accurate representation of the geometry of the discontinuities is essential for identification of kinematically correct failure modes then static stability analyses of the vaiont italy landslide of october 9 1963 are used to show that the dda results compare favorably with previously published limit equilibrium studies using similar geometries and that the location and number of discontinuities have a significant effect on the predicted stability and failure velocities of the landslide dynamic dda simulations of the vaiont landslide show that the peak velocity increases up to 50 as the number of blocks increases indicating that internal disintegration of the landslide mass results in increasing acceleration and higher peak velocity dda analyses simulating pore pressure rise resulting from frictional heating of the basal slide plane show that the peak velocity similarly increases up to 50 as the number of blocks increases the magnitude of the increase in peak velocity as a result of disintegration i e increasing number of blocks suggests that as much attention should be paid to the geometry of discontinuities as is typically paid to shear strength and pore pressure

new evidence that the lower cambrian leny limestone at callander perthshire belongs to the dalradian supergroup and a reassessment of the exotic status of the highland border complex

composite rock slope kinematics at the current randa instability switzerland based on remote sensing and numerical modeling abstract kinematic analysis of slope instabilities in brittle rock is crucial for understanding the reaction of the rock mass to external forcing factors in steep terrain inaccessibility often limits collection of relevant data and remote sensing techniques must be applied this is the case at the current randa rock slope instability in southern switzerland where a total volume of about 5 6 million m3 moves at a rate of up to 30 mm yr a large portion of the unstable rock mass is exposed in an 800 m high inaccessible cliff the main scarp of the may 1991 rock slope failure between 2005 and 2007 a comprehensive suite of remote sensing techniques including photogrammetry lidar and gb dinsar was combined with 3d geodetic measurements to characterize the rock mass structure and displacement patterns photogrammetry and lidar data were measured simultaneously from a helicopter using a system allowing for oblique view angles which provided optimal observations of the steep rock cliff we used these datasets to map large scale structures and extract their orientation and minimum persistence as well as to characterize the 1991 failure scarp the northern part of the may 1991 failure surface shows a transition from stepped planar sliding at the base to failed rock bridges in the center to tensile failure close to the vertical head scarp kinematic analysis of the discontinuity sets in the currently moving rock mass shows that both toppling and translational sliding are feasible failure mechanisms toppling is more likely for steep faces above 2200 m whereas translational failure is more likely in the lower portion of the instability interpretation of gb dinsar displacement maps revealed similar kinematic behavior and also allowed identification of a basal rupture zone and lateral release plane bounding the instability displacement vectors derived from geodetic surveying provided new insights into the 3d kinematic behavior of the instability all information extracted from different data sets were integrated in a conceptual model which was then investigated with 2d numerical simulation using the discontinuum code udec the numerical models were able to reproduce the hypothesized kinematic behavior well

a conservative and consistent lagrangian gradient smoothing method for earthquake induced landslide simulation abstract numerical study of earthquake induced landslides plays an important role in the disaster prevention and post earthquake managements thanks to its mesh free feature the sph smoothed particle hydrodynamics method has significant advantages over the traditional grid based methods in dealing with extremely large deformation problems such as high speed fluid like landslides however sph is unstable when the material is in tension which is widely known as the tensile instability problem in sph although the instability issue can be removed to certain stand by particular ad hoc techniques the root cause of the problem is not addressed in addition such ad hoc techniques require additional user defined parameters which is difficult to make universally applicable in this study a conservative and consistent lagrangian gradient smoothing method l gsm is proposed for fluid like landslide simulations based on the recently developed meshfree l gsm in the present l gsm the strong form of governing equations is discretized using the gsm gradient operator in a conservative and consistent manner moreover a simple and accurate boundary treatment for free surface and solid boundary is newly proposed for l gsm to handle the complicated free surface and solid boundary existed in the landslide problems finally the proposed conservative and consistent l gsm framework is validated by a soil column collapse benchmark and three real landslide problems results show that our l gsm can give an accurate and reliable solution to the fluid like landslide problem with a high efficiency the treatments for free surface and solid boundary are also proven very effective in producing desired boundary conditions both cohesive soil column collapse example and wangjiayan landslide example demonstrate that l gsm is indeed free from the tensile instability problem

the northeast arran trough the corrie conundrum and the highland boundary fault in the firth of clyde sw scotland two strikingly different successions of lower carboniferous mainly tournaisian sedimentary rocks are closely juxtaposed on the ne coast of the island of arran sw scotland near the village of corrie a thin succession 17 m of tournaisian rocks is preserved whereas in the neighbouring fallen rocks laggan area correlative rocks are 300 m in thickness these contrasting successions are separated by the laggan fault which is a landward extension of the submarine brodick bay fault marking the sw boundary of the northeast arran trough the contrasting thickness and stratigraphy of the two sequences of sedimentary rocks result from juxtaposition of shoulder and trough deposits along the laggan brodick bay fault although originally a normal basin defining fault later sinistral movements caused significant displacement of the ne arran trough together with a segment of the highland boundary fault from their original positions the most northerly occurrence of the highland boundary fault on arran is thought to be the truncated northern end of the corloch fault to the sw the surface trace of the highland boundary fault is largely obscured by a palaeogene granite body but it is present on the west side of the island near dougrie the highland boundary fault appears to be displaced to the south in kilbrannan sound by a series of nw trending sinistral transcurrent faults thus the anomalous trend of the highland boundary fault and narrowing of the midland valley of scotland in the firth of clyde area may be explained by later fault movements and intrusion of the palaeogene north arran granite pluton

runout simulation of seismic landslides using discontinuous deformation analysis dda with state dependent shear strength model the reliable numerical simulation of the landslide process contributes to the establishment of evidence based disaster mitigation measures in seismically active zones to achieve this goal a simpl

cyclostratigraphic constraints on the duration of the datangpo formation and the onset age of the nantuo marinoan glaciation in south china abstract constructing an accurate timeline is critical for reconstructing the earth systems through critical transitions in climate geochemistry and life existing dates constrain synchronous initiation ca 717 ma and termination ca 660 ma of the sturtian glaciation from multiple continents the termination of the younger marinoan glaciation is also well dated at ca 635 ma but the onset of this glaciation is only roughly constrained as ca 654 ma south china and ca 639 ma namibia to test if the marinoan glaciation started close to ca 654 ma or ca 639 ma we have conducted a cyclostratigraphic study on the cryogenian non glacial datangpo formation that conformably overlies and underlies sturtian and marinoan glacial diamictites respectively in a deep water basin section in south china a total of 28 765 magnetic susceptibility ms measurements from a drillcore of the 292 m thick muddy siltstone and shale dominated datangpo formation are used for cyclostratigraphic analysis the results reveal significant decameter to meter scale sedimentary cycles of 16 12 m 3 6 3 0 m 1 0 0 8 m and 0 6 0 4 m the ratios of these cycle wavelengths match well with those of the milankovitch cycles calibrated for the cryogenian period the established astrochronologic time scale suggests that the duration of the datangpo formation is about 9 8 million years together with the radiometric age of ca 660 ma for the termination of the sturtian glaciation the cyclostratigraphic data suggest that the nantuo marinoan glaciation in south china initiated at ca 650 ma which is slightly younger than but consistent with the ca 654 ma u pb age from the top of the datangpo formation in shelf sections this age however is significantly older than the ages obtained from marinoan age glacial diamictites in south china ca 636 ma and namibia ca 639 ma given that most of the shelf sections may have suffered from glacial erosion obtaining the onset age of the marinoan glaciation should focus on relatively complete deep water successions

3d simulation of vajont disaster part 1 numerical formulation and validation abstract this work presents a numerical method for the simulation of landslides generated impulse waves and its application to the historical vajont case study the computational tool is based on the particle finite element method pfem a lagrangian strategy that combines the finite element solution of the governing equations with an efficient remeshing strategy to deal with large deformation problems after presenting the numerical formulation different landslide impulse wave problems with froude number ranging from 0 5 to 2 8 are analyzed to validate the proposed methodology the computational method is shown to be able to reproduce accurately the landslide runout the momentum transfer between the sliding material and the impounded water and the consequent wave propagation observed in experimental physical models then the pfem model is applied to the numerical simulation of the vajont disaster which is analyzed with a fully resolved three dimensional model the numerical results are discussed and compared to the post event observations and the numerical results of other computational methods the results in terms of landslide velocity and runout geometry of the deposit maximum water runup dam overtopping wave and water discharge in the downstream valley are in good agreement with observations and reconstructions the calibration and validation performed for this study form the basis for the pfem analyses presented in a companion paper finalized to simulate different scenarios of the vajont rockslide considered in the experimental tests done a year before the disaster

the role of the highland border ophiolite in the 470 ma grampian event scotland field and petrological studies of the highland border ophiolite demonstrate that it was obducted onto the neoproterozoic ordovician rocks of the dalradian block and not emplaced against them by post orogenic strike slip movement it was welded onto the upper southward younging limb of the already recumbent tay nappe d1 and deformed by the downbend antiform d4 however its emplacement was not accompanied by significant internal deformation of the dalradian block as the ophiolite is correlated with those at clew bay tyrone and shetland this result will necessitate complete revision of the current model for basin closure on the southeastern margin of laurentia

the highland border complex scotland a paradox resolved a previously inexplicable difference between the highland border complex scotland and its correlative in ireland the clew bay complex is that rocks of caradoc ashgill age occur only in the former we reject evidence from supposed chitinozoa for this dichotomy no sedimentary rocks of proven age younger than arenig occur in the highland border complex consequentially the stratigraphy must be totally recast and the exotic terrane model replaced by one in which a largely autochthonous highland border complex in stratigraphical continuity with the dalradian grampian terrane was overridden by the highland border ophiolite midland valley terrane tectonic models for se laurentia are thereby considerably simplified

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

ejection landslides triggered by the 2008 wenchuan earthquake and movement modelling using aerodynamic theory and artificial disintegration collision technique many ejection landslides in the 2008 wenchuan earthquake exhibited unusually dramatic behaviour in which a huge sliding mass was launched into the air and supported for a long distance because of the aerodynamic effect in this paper the formation conditions and movement characteristics of ejection landslides are analysed the flight behaviour of the centroid of the ejection mass is studied by numerical solution with and without the aerodynamic effect the impact and movement processes of the sliding mass are simulated by incorporating an advanced discretisation approach into discontinuous deformation analysis dda simulation results of the dayanke rock avalanche induced by the 2008 wenchuan earthquake show that the aerodynamic effect significantly affects its flight behaviour before collision simultaneously the colluvium on the slope surface remarkably reduces its traveling speed and runout moreover the initial angle between the velocity of the detached ejection mass and the horizontal direction strongly affects the flight distance and final deposition pattern of the avalanche

3d numerical modeling using smoothed particle hydrodynamics of flow like landslide propagation triggered by the 2008 wenchuan earthquake abstract the extremely strong wenchuan earthquake triggered thousands of landslides in sichuan province china flow like landslides such as the tangjiashan wangjiayan and donghekou landslides were among the most destructive causing many casualties and serious economic damage it is therefore important to identify the flow mechanisms and investigate the specific characteristics of these flow like landslides this paper presents a three dimensional model based on smoothed particle hydrodynamics sph to simulate rapid landslide motion across 3d terrain the navier stokes equations in a cfd framework are used as governing equations and artificial viscosity is incorporated into the pressure terms in the momentum equation to dissipate energy to avoid numerical oscillation and particle penetration thus improving the stability of the numerical results a non newtonian fluid model the bingham model has proven suitable for describing the relationship between the shear strain rate and the shear stress in highly deformed soil materials in the proposed model it is used as the constitutive model to describe the fluidization characteristics of flow like landslides combined with the mohr coulomb yield criterion the model incorporates a no slip boundary condition to consider the effect of a solid boundary on slope movement ghost particles are created and assigned an artificial velocity the viscous force caused by the solid boundary is calculated using the relative velocities between the fluid and the boundary particles open multiprocessing openmp an api for multi platform shared memory parallel programming is used to improve the efficiency of the sph code running to show the validity of the proposed approach a benchmark problem of 3d dam break was simulated the calculated distances of the surge front at different times agree well with the test results numerical modeling of the propagation of the tangjiashan wangjiayan and donghekou landslides was performed by the application of sph models to real flow like landslides the whole flow processes of these flow like landslides across the 3d terrain are represented the landslides change direction split or join in and spread or contract in their flow path in response to the local topography time history curves of the velocity and displacement were obtained to analyze the movement characteristics of the landslide mass the shapes of the deposition zones after slide occurrence were investigated comparisons of the sph simulated geometry and the surveyed landslide configurations for the tangjiashan wangjiayan and donghekou landslides were conducted and show a high degree of similarity this indicates that the proposed 3d sph model can accurately represent the evolution of the final slide shape the prediction of the fluidization characteristics of earthquake induced flow like landslides can notably reduce sudden loss of life as it provides a means for mapping hazardous areas for estimating the hazard intensity and for identification and design of appropriate protective measures

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

evidence for the lower palaeozoic age of the tay nappe the timing and nature of grampian events in the scottish highland sector of the laurentian margin stratigraphical and structural evidence for latest proterozoic phanerozoic deposition of the dalradian supergroup in the scottish highlands sector of the laurentian margin is incompatible with geochronological data suggesting c 750 ma knoydartian and c 600 ma grampian orogenesis the age of the 590 2 ma ben vuirich granite is critical to the dating of grampian orogenesis fabric evidence indicates that the granite predates d2 while its relationship to d1 is unclear in this paper the d1 d2 overprint during the evolution of the tay nappe a regional grampian structure is examined documentation of the distribution style and orientation of d1 and d2 structures from well exposed sections near the highland border has allowed the development of a kinematic model for the d1 d2 deformation in this model early crustal shortening resulted in d1 upright structures that were subsequently overturned in a d2 se directed shear regime associated with underthrusting of a southern landmass the model is best explained in terms of a single continental collision event with no evidence of a time gap between d1 and d2 this analysis is consistent with pre regional d1 intrusion of the ben vuirich granite and an early palaeozoic grampian orogeny

the age and tectonic significance of the bute amphibolite highland border complex scotland sm nd and k ar isotopic determinations on an amphibolite from the highland border complex yield cambrian ages collisional events which might have generated the amphibolite appear incompatible with the passive margin character of laurentia at that time a possible explanation is that the part of the highland border complex containing the amphibolite and associated rock units was generated outside laurentia

viscous boundary of dda for modeling stress wave propagation in jointed rock note roches reference lmr article 2007 010view record in web of science record created on 2007 09 24 modified on 2016 10 14

the highland border rocks and their relation to marginal basin development in the scottish caledonides it has long been known that the highland border includes an assemblage of altered serpentinites gabbros spilitic lavas ferruginous and manganiferous cherts black phyllites quartzose clastics and amphibolites new work confirms that many of these rocks represent a dismembered tectonically emplaced ophiolite of caledonian age which originated in a narrow oceanic basin within or bordering the dalradian sedimentary pile the ophiolitic rocks were expelled from the basin as thrust sheets transecting d1 structures studies in the sw highlands suggest emplacement during d2 synchronous with se translation of the tay nappe this implies that the ophiolite originated in the n the highland border rocks are seen as marginal to a long lived northward dipping subduction zone within the southern uplands the evolution of the ballantrae ophiolitic complex the midland valley and the dalradian sedimentary basin are considered within this framework

rock slope instability assessment using spatially distributed structural orientation data in darjeeling himalaya india we discuss a geographic information system gis based methodology for rock slope instability assessment based on geometrical relationships between topographic slopes and structural discontinuities in rocks the methodology involves a regionalization of point observations of orientations azimuth and dip of structural discontinuities in rocks in order to generate a digital structural model dstm b testing the kinematical possibility of specifi c modes of rock slope failures by integrating dstms and digital elevation model dem derived slope and aspect data and c computation of stability scenarios with respect to identified rock slope failure modes we tested the methodology in an area of 90 km in darjeeling himalaya india and in a small portion 9 km within this area with higher density of field structural orientation data the results of the study show better classification of rock slope instability in the smaller area with respect to known occurrences of deep seated rockslides than with respect to shallow translational rockslides implying that structural control is more important for deep seated rockslides than for shallow translational rockslides results of scenario based analysis show that in rock slopes classified to be unstable stress induced rock slope instability tends to increase with increasing level of water saturation the study demonstrates the usefulness of spatially distributed data of orientations of structural discontinuities in rocks for medium to small scale classification of rock slope instability in mountainous terrains

block theory and its application block theory is a geometrically based set of analyses that determine where potentially dangerous blocks can exist in a geological material intersected by variously oriented discontinuities in three

the 1963 vajont landslide a numerical investigation on the sliding surface heterogeneity the 1963 vajont landslide is a key case in landslide literature because it was catastrophic and because a lot of accurate data were collected before and after its occurrence in this paper the main focus is on the possible heterogeneity of the sliding surface involved by the landslide motion which is reflected by a heterogeneous distribution of the dynamic basal friction coefficient assuming a given zonation of the sliding surface our strategy was to apply a 2d lagrangian model to compute the landslide motion and to find the values of for each zone leading to the best agreement between the computed and the observed final deposit following some hints from the literature we have explored heterogeneous configurations composed of up to four different zones including also the homogeneous case by means of a 2d numerical model ubo block2 that handles the landslide as a mesh of blocks and runs quickly enough to allow the computation of tens of thousands of simulations in a reasonable computing time it is found that the four zone zonation produces the best fit or the least misfit which is a strong hint that the gliding surface involved different geotechnical units

prograde temperature time evolution in the barrovian type locality constrained by sm nd garnet ages from glen clova scotland abstract the timing of garnet growth during metamorphism associated with the grampian orogeny in the sillimanite zone of the barrovian type locality in glen clova scotland was determined by sm nd geochronology two high precision garnet whole rock ages were achieved by employing hf partial dissolution of garnet separates to optimize purity multiple garnet growth generations were identified on the basis of the geochronology and detailed textural and chemical data an early stage at 472 9 2 9 ma during d 2 deformation under garnet zone conditions c 500 550 c and a later stage at 464 8 2 7 ma during or slightly after d 3 deformation mostly under sillimanite zone conditions peak temperature of c 660 c but possibly including some growth during kyanite zone conditions when combined with recently published garnet ages from the kyanite and garnet zones the data suggest that peak metamorphic temperatures in at least these three of barrow9s zones were achieved roughly contemporaneously the difference between garnet zone and sillimanite zone peak temperature attainment is 2 8 3 7 ma the near contemporaneity of peak temperature attainment in different metamorphic zones requires an additional source of heat beyond thermal relaxation of a variably over thickened crust we suggest that local igneous intrusions with synmetamorphic ages provided that additional heat

coulomb mechanics and relief constraints explain landslide size distribution despite the idea that topography could control landslide size scaling law the contribution of landscape geometry to landslide size distribution remains elusive we define a simple mechanical model accounting for the complexity and variability of natural hillslopes to infer the landslide depth probability density function pdf in a given landscape and upscale it to landslide area pdf this model is based on both a mohr coulomb stability analysis accounting for cohesion and friction and a criterion of intersection between rupture planes and the topographic surface it can reproduce the distribution of observed landslide areas triggered by several past events we found the ranges of effective cohesion 10 35 kpa and friction 20 45 consistent with previous estimates of large scale rock strength using synthetic topographies we found that the finite geometry of hillslopes length steepness and concavity exerts a first order control on the pdf of landslide areas especially for large landslides

criteria for rapid sliding i a review of vaiont case vaiont slide has been represented by a model of two interacting evolutive wedges mass conservation during the motion implies that the upper wedge transfers mass to the lower one through an internal shearing plane the model respects available in situ observations it was formulated in dynamics terms outcomes of the analysis are the determination of safety factors of the valley before dam impoundment and the calculation of run out distance once the motion starts rock strength degradation as motion develops has also been included this degradation even if it is intense was unable to explain the very high estimated landslide velocities

petrochemistry and tectonic significance of the highland border suite mafic rocks the metamorphosed mafic rocks of the ophiolitic highland border suite on arran and bute are of 2 types greenschist facies pillow lavas and epidote amphibolite facies hornblende schists respectively both types have been affected by post magmatic alteration processes including spilitization i e na enrichment coupled with ca depletion on the basis of 9immobile element9 chemistry and other criteria the mafic rocks are split into 2 magmatic groups a tholeiitic one which shows the effects of extensive low pressure fractionation e g fe and ti enrichment and a less fractionated alkaline group that contains relict al and ti rich clinopyroxenes the tholeiitic rocks are similar to modem ocean floor or marginal basin basalts and the alkaline rocks show affinities with 9within plate9 basalts this 9magma type9 and 9tectonic setting9 dichotomy is found at other highland border localities and is present in both the pillow lavas and hornblende schists the highland border suite mafic rocks may have formed as tholeiitic ocean basin crust upon which alkaline ocean island lavas had been erupted or alternatively as is suggested in this paper they may have formed during the early stages of development of a pre grampian marginal basin of cambrian or cambro ordovician age

large p t gap between ballantrae blueschist garnet pyroxenite and surrounding ophiolite southern scotland uk diapiric exhumation of a caledonian serpentinite melange abstract the ballantrae ophiolite in southern scotland includes a nee sww trending serpentinite melange that contains blocks of mafic blueschist and high pressure granulite facies metapyroxenite sm nd metamorphic age 576 32 and 505 11 ma tectonic blocks of mafic schist are less than 3 3 m in size and have greenschist blueschist or epidote amphibolite facies assemblages corresponding to the high pressure intermediate type metamorphic facies series adjacent rocks of the serpentinite melange are hydrothermally altered morb like ophiolitic basalt prehnite pumpellyite facies dolerite actinolite oligoclase sub facies and gabbro amphibolite facies all with assemblages that are diagnostic of the low pressure metamorphic facies series the difference in metamorphic facies series and parageneses of minerals between the high pressure mafic blocks and the adjacent low pressure ophiolitic meta basic rocks suggests that the former were exhumed from 25 km depth within a cold subducted slab and were juxtaposed with the latter the bottom of a morb like ophiolite in the hanging wall of a trench an ene wsw trending 501 12 ma volcanic arc belt extends for 3 km south of the serpentinite melange we suggest that ridge subduction associated with a slab window created arc related gabbro 483 4 ma at byne hill and within plate gabbro 487 8 ma at millenderdale final continental collision created the duplex structure of the ballantrae complex that includes the hp blocks and serpentinite melange these relations define diapiric exhumation in the caledonian orogen of sw scotland

tectonic significance of the highland boundary fault scotland none of the major roles assigned to the highland boundary fault such as a transcurrent fault with an orogen parallel sinistral displacement of several hundred kilometres or terrane boundary are confirmed the highland boundary fault can be traced ne sw across scotland for 240 km and defines the northern margin of the midland valley except for small outliers of late palaeozoic rocks on the nw side it separates the highland border ophiolite and dalradian rocks of neoproterozoic early ordovician age grampian terrane to the nw from late silurian early carboniferous rocks midland valley terrane to the se the present highland boundary fault is a steep nw dipping post early devonian reverse fault that probably terminates sw of bute stratigraphical and provenance links and palaeostress data limit post early devonian lateral displacement to

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

behavior of rock in slopes the behavioral modes to which a rock slope is susceptible are many and complex this article discusses a long but not exhaustive list of common failure styles highlighting observable characteristics that distinguish one from another slopes in both strong and weak rock masses are considered principles are stated to explain how and why different failure modes develop in different rocks the discussion is illustrated with examples of diverse failure modes in foliated metamorphic rocks developed in the walls of an eroded spillway runout