numerical models for planning landslide risk mitigation strategies in iconic but unstable landscapes the case of cinque torri dolomites italy abstract this study deals with the numerical modelling of large deep seated instability processes affecting the cinque torri group dolomites italy which is a unesco world heritage site the aim is to evaluate the role of intrinsic causal factors and to assess the failure mechanism proposed in previous investigations the geological model is based on topographic geological and geomechanical surveys complemented with mineralogical physical and geotechnical lab analyses for parameters determination the numerical simulations have been carried out using a distinct element method code on conceptual and site specific slope models a series of parametric analyses have been performed to characterize the role of the different predisposing factors potentially related with the ongoing rock spreading i load of the rocky pinnacles ii lithology stratigraphy and attitude of the geological units iii discontinuity sets in the rock mass iv degradation of the mechanical properties the results of this study suggest that the shear zone initiation is controlled by stress concentration due to the loading of the dolomitic pinnacles whereas its shape appears to be structurally controlled by the dip slope attitude of bedding in clay rich mudstones the interpretation of the modelling results has provided a better understanding of the ongoing deformation process which can help in targeting effective and low impact landslide risk mitigation strategies in this iconic landscape

deep seated gravitational slope deformations related landslides and tectonics abstract deep seated gravitational slope deformations and their relationships with tectonic deformation of rocks is considered to examine the viewpoint of tectonics as a causative factor in slope deformation first a distinction is made between the different types of deep seated gravitational slope deformation then the geomorphological and structural effects of the different macrostructural deformations induced by tectonics on the scale of the whole deforming ridge is briefly discussed finally some case studies that represent either verified or possible cases of gravity deformation in response to tectonic activity are used as illustration

some considerations concerning seismic geomorphology and paleoseismology abstract seismic geomorphology studies landforms which developed in connection with earthquakes among them two different end members may be distinguished 1 seismo tectonic landforms including surface faults and fractures land uplift and subsidence at different scales surface bulges elongate ridges and any other permanent ground deformations directly related to tectonic stress and 2 seismo gravitational landforms such as landslides deep seated gravitational slope deformations sinkholes and fissures due to sediment compaction or liquefaction and sand blows connected with both seismic shaking and gravitational stress a clear cut distinction between the two categories of landforms is not always easy to make and in many instances not really useful while there are in many cases ground effects that might be and should be considered as simultaneous combinations of seismo tectonic and seismo gravitational processes this applies especially to surface fracturing and faulting which could be the combined result of tectonic stress stress produced by seismic shaking and gravitational stress the objective of this paper is to review selected case histories mainly from italy and the mediterranean region in order to show the importance of a comprehensive study of earthquake generated landforms for understanding the seismicity level of the area under investigation we argue that in earthquake prone areas seismic landforms often constitute typical patterns seismic landscapes whose recognition mapping and paleoseismological analysis may help in the evaluation of seismic hazards

extensive deformations of rock slopes in southern coast mountains southwest british columbia canada extensive deformations of mountain slopes occur in crystalline intrusive rocks in the southern coast mountains of british columbia typical morphological evidence of slope movement includes extensive systems of tension cracks grabens and antislope scarps collectively referred to here as linears these landforms involve displacements along penetrative joints observed in surface exposures kinematic tests on rock structural data indicate that the observed patterns of linears are generally consistent with the feasible gravitational movements along the dominant discontinuities most sites indicate sliding as the most likely initial mode of movement followed by or accompanied by toppling and toppling induced sliding movements and do not support the view that linears are the traces of active faults

evaluation of prediction capability of the artificial neural networks for mapping landslide susceptibility in the turbolo river catchment northern calabria italy abstract landslides are one of the most widespread natural hazards that cause damage to both property and life every year and therefore the spatial distribution of the landslide susceptibility is necessary for planning future developmental activities in this paper the artificial neural network ann technique is tested for developing a landslide susceptibility map in turbolo river catchment north calabria south italy landslides were mapped through air photo interpretation and field surveys by identifying both the landslide depletion zones dzs and accumulation zones azs and relevant geo environmental thematic layers pertaining to landslide predisposing factors were generated using air photo interpretation field surveys and geographic information system gis tools ten predisposing factors were related to the occurrence of landslide lithology faults land use drainage network and a series of topographic factors elevation slope aspect plan curvature topographic wetness index twi and stream power index spi in order to evaluate and validate landslide susceptibility the dzs were divided in two groups using a random partition strategy the first group training set was used to prepare the susceptibility map employing a back propagation learning algorithm in the idrisi taiga software the second group testing set was used to validate the landslide susceptibility model using the confusion matrix and the receiver operating characteristic roc curve the susceptibility map was classified into five susceptibility classes very low low moderate high and very high about 46 of the study area falls in high to very high susceptible classes and most of the dzs mapped 87 3 occur in the same classes the validation results showed satisfactory agreement between the susceptibility map and the dzs locations over 85 of the dzs of the validation set are correctly classified falling in high and very high susceptibility areas also the roc curve had shown an area under curve auc value of 0 90 which demonstrates the robustness and good reliability of the landslide susceptibility model according to these results we conclude that the map produced by the artificial neural network is reliable and the methodology applied in the study produced high performance and satisfactory results which may be useful for land planning policy

the hermitage of cerbaiolo tuscany italy stability conditions and geomorphological characterization the italian cultural heritage is one of the most noticeable in the world an important part of it is subjected to natural hazard and risk conditions religious buildings due to their location on impervious sites are particularly exposed to landslides in this paper we study the hermitage of cerbaiolo tuscany central italy the hermitage founded in the 8th century as a benedictine monastery is now a franciscan women institute seat the buildings are on the edges of a limestone plate overlapped to a clayey formation falls toppling and slides are present along the limits of the plate due to the geomechanics properties of the rock and to the contrast between the two lithological complexes in order to identify the main joint sets affecting the rock mass a structural geological survey was carried out and four sets are identified the rock plate was classified according to bieniawski barton and geological strength index approaches the outcomes confirm the predisposing factors to mass movements corresponding to the intensity and characteristics of fracturing of the rock mass with regard to the slope stability analysis a failure mechanism involving sliding along a single plane plane failure was assumed on the first approximation the analyses take into account the presence of tension cracks as an indicator factor for the instability phenomenon the results of stability analyses performed in static and seismic conditions indicate a widespread instability condition the dip slope direction the properties and type of discontinuities and the local variation of composition influence the hazard assessment

evolution of uphill facing scarps by flexural toppling of slate with high angle faults abstract uphill facing scarps are typical surface expressions of deep seated gravitational slope deformations and are commonly created by flexural toppling however their evolution mechanisms are not well understood partly because of the difficult in observing their internal structures this study therefore performed high resolution geomorphic analyses and thorough geological mapping in a slate rich area where flexural toppling has occurred and uphill facing scarps have developed following slope failures was crucial in exposing the inside of the toppled slate amid the toppled area uphill facing scarps developed when slate contained a crush zone of a high angle fault as a weak layer uphill facing scarps developed with the rotation of a wedge which was defined by the high angle fault and cleavage that passed through the intersection of the fault and basal hinge surface of the toppling the wedge developed up or downslope of the fault depending on whether the fault dipped into the slope or valleyward during wedge rotation displacement occurred along the fault and an uphill facing scarp developed along the fault the uphill facing scarp became higher when the cleavage dipped into the slope and the fault dipped valleyward when the fault dipped into the slope the uphill facing scarp did not grow significantly when a high angle fault was not involved flexural toppling of slate continuously deformed the slope and was unlikely to form an uphill facing scarp when flexural toppling extended to the ridge top it generally formed a ridge top depression regardless of whether a fault was involved flexural toppling of rock mass created many openings making the rock highly permeable however when a high angle fault with a thick crush zone was involved groundwater was stored between the fault crush zone and flexural toppling hinge surface which could predispose the flexural toppling to catastrophic failure during a rainstorm and or earthquake

buckling deformations at the 2017 xinmo landslide site and nearby slopes maoxian sichuan china abstract a large catastrophic rock avalanche with a total volume of 18 0 106 m3 occurred at 5 38 am 24th june 2017 at xinmo village maoxian sichuan china resulting in 102 casualties 10 deaths 3 injuries and 89 missing we have been conducting a geological and geomorphological investigation in and around the xinmo landslide site since 2015 and we present our results here including data obtained before and after the landslide event the landslide which had an initial volume of 4 46 106 m3 of its source area was induced by rainfall on a previous landslide scar near the ridge top this initial landslide then struck and remobilized older landslide deposits in the middle and lower parts of the slope which subsequently buried xinmo village at the landslide toe the landslide occurred on a dip slope of triassic calcareous psammitic and pelitic schists the bedding plane which dips downslope to the south with an orientation of n80 w 48 s and high angle ne sw striking joints bounded the landslide source area at its base and sides respectively satellite image analysis and field observations of the slope of the landslide scar before and after the landslide strongly suggest that the beds in the source area had already begun gravitationally deforming e g buckling prior to the 2017 landslide moreover pits on the slip surface were likely the result of the dissolution of calcareous material dissolution probably reduced the rock strength along the bedding plane a rainfall event from the 16th to 24th of june 2017 probably dominated the groundwater drainage and finally triggered the catastrophic rock avalanche in addition to the 2017 landslide the hillslope just to the east of the xinmo landslide exhibits pronounced gravitational slope deformation including a tent like structures and warps induced by buckling this suggests that this slope could also fail like the xinmo rock avalanche during a future rainfall or earthquake event

gravitational slope deformation of a resurgent caldera new insights from the mechanical behaviour of mt nuovo tuffs ischia island italy abstract ischia island italy is an impressive example of the rare phenomenon of caldera resurgence the emplacement and replenishment of magmas at shallow depth resulted in a vertical uplift of about 900 m concentrated in the western portion of mt epomeo 789 m a s l as a consequence of this uplift the island has experienced several slope instabilities at different scales since the holocene from shallow mass movements to large rock and debris avalanches these mass wasting events which mobilised large volumes of greenish alkali trachytic tuff the mt epomeo green tuff megt were strictly related to volcano tectonic activity and the interaction between the volcanic slopes and the hydrothermal system beneath the island deep seated gravitational slope deformation dsgsd at mt nuovo located adjacent to densely populated coastal villages is an ongoing process that covers an area of 1 6 km 2 the mt nuovo dsgsd involves a rock mass volume of 190 mm 3 and is accommodated by a main shear zone and a series of sub vertical fault zones associated with high angle joint sets to improve our understanding of this gravity induced process we performed a physical porosity and permeability and mechanical uniaxial and triaxial deformation experiments characterisation of two ignimbrite deposits both from the megt that form a significant component of the nw sector of mt epomeo the main conclusions drawn from our experiments are twofold first the presence of water dramatically reduces the strength of the tuffs suggesting that the movement of fluids within the hydrothermal system could greatly impact slope stability second the transition from brittle dilatant to ductile compactant behaviour in the tuffs of the megt occurs at a very low effective pressure analogous to a depth of a couple of hundred metres and that this transition is likely moved closer to the surface in the presence of water we hypothesise that compactant porosity decreasing behaviour at the base of the layer could therefore facilitate slope instability although our results show that transient exposure to 300 c does not influence the short term strength of the tuff we speculate that the high in situ temperature could increase the efficiency of brittle and compactant creep and therefore increase the rate of slope deformation taken together our experimental data highlight a potentially important role for the hydrothermal system that reaches a minimum depth of 1 km in dictating the dsgsd at mt nuovo an understanding of this deformation process is not only important for the proximal coastal villages at risk of engulfment by a large debris avalanche but also for the towns and cities along the coast of the gulf of naples that are at risk to a secondary consequence of such an avalanche a tsunami wave

regional scale relief evolution and large landslides insights from geomechanical analyses in the tinee valley southern french alps abstract recurring large rock slope failures of the argentera mercantour massif southern french alps over the past 20 000 years were identified in the field and analyzed using a continuum mechanics approach based on material weakening in a three dimensional finite difference model we compared a mountain slope failure model neglecting the effect of rock strength loss with a model simulating the effect of strength loss and integrating cohesional weakening and frictional strengthening processes the good correspondence between the relative chronology and location of observed and simulated deformations shows that 1 the gradual loss of rock mass strength related to stress release effects following the pleistocene deglaciation can be as long as several thousands of years and 2 the causes and triggering of the present day active landslides are related to this long failure history our study suggests that the episodic nature of massive rock slides can be explained through the gradual development of tensile and shear failure and time dependent strength degradation our numerical model is a good reproduction of large landslides at the regional scale of a mountainous massif

seismic prospecting of a slope affected by deep seated gravitational slope deformation the lago sackung calabria italy abstract in this study seismic reflection and refraction were used to study the sackung of lago calabria italy the seismic track is roughly 1200 m long seismic reflection analysis has seldom been used to study mass movements structurally landslides tend to be extremely complex and the landslide body is not a good medium for seismic waves because of dispersion and noise however through the use of recent sophisticated software it has become possible for seismic reflection to obtain good results in this case study a package called seistrex 3 was used by means of static and topographic corrections enhanced by filtering and migration a seismic profile with good resolution of the geometry of layers and faults to depths of 100 400 m was obtained this study shows that seismic reflection is more useful than seismic refraction for examining the internal structure of a landslide

numerical study on deep seated gravitational slope deformation in a shale dominated dip slope due to river incision abstract based on numerical simulation this study investigates the triggering factors and evolution of deep seated gravitational deformation in a dip slope consisting of a shale dominated sequence of sediments results from continuum based finite difference numerical modeling demonstrate that long term strength degradation of a rock mass is a prerequisite for the development of gravitational slope deformation and that river incision resulting in change of slope geometry and corresponding stress concentration and redistribution is a major driving mechanism for the progressive evolution of deep seated gravitational slope deformation dsgsd numerical simulation considering the influence of weak planes indicates that the bedding planes control the strength of rock mass and form a structural constraint on the development of gravitational slope deformation a satisfactory correlation between the distribution of numerically simulated plastic shear bands and weak zones in drill cores demonstrates that the weak zones within the slope are formed due to gravitational slope deformation furthermore numerical simulation shows a link between geomorphological development and internal deformation of the slope which aids in the understanding of relationships between interior deformation of the slope the exterior geomorphology and related effect factors including river incision and strength degradation

the sant agata feltria landslide marche region central italy a case of recurrent earthflow evolving from a deep seated gravitational slope deformation abstract this paper examines the evolution of a large scale earthflow located in the northern sector of the marche region central italy in this area mass movements of different typology are particularly frequent since geological and geomorphological conditions often favour slope instability among these many mass movements the one affecting the historical village of sant agata feltria has been chosen also because its evolution has been recorded in chronicles starting from ancient times in fact reactivations of the 5 4 km long earthflow crossing the village have been quoted at least 12 times starting from the 16th century even though more ancient activations have been inferred historic researches and geomorphologic analyses allowed the detailed reconstruction of the evolution and the mechanism of the phenomenon outlining its causes and delineating risk zonation in particular a deep seated gravitational movement lateral spreading marked by trenches and ponds has been recognised at the top of the landslide the earthflow has been interpreted as a more surficial side effect of the deep seated phenomenon which constitutes its source area it has also been highlighted that reactivations coincided with long lasting and intense rainfalls whilst no direct connection seems to exist with earthquakes even though the area is seismically rather active and seismic shocks could have been among the major triggering factors for the deep seated deformation the oldest and probably most catastrophic recorded event itself 1561 a d took place during the first stages of a period of severe climate that involved the whole of europe

a deep seated compound rotational rock slide and rock spread in se spain structural control and dinsar monitoring abstract the northern slope of the sierra de aitana eastern betic cordillera is characterized by a long mountain front with a prominent eocene limestone scarp overlying ductile eocene marlstones this stratigraphic feature and the highly stepped topography produced by several normal faults favor gravitational processes such as rock avalanches rock slides and rock falls this paper reports a compound landslide comprising a rotational rock slide and slab type lateral spreading affecting these materials with blocks of volumes up to 106 m3 this lateral spread process produced singular and spectacular morphological features the simas de partagat which are trenches 20 m wide and up to 40 m deep formed by the widening of discontinuities the use of a differential sar interferometry technique for monitoring this landslide over a time span of 11 yr has revealed that velocity of movement is insignificant with rates comprised between 0 and 2 mm yr 1 and cumulative negligible displacements individual rock blocks initially located at the free face of the scarp were affected by slides at the base of the scarp descending from a few to several dozen meters along the slope blocks broke up as displacement progresses with several in different stages of evolution being recognizable along the slope differential sar interferometry shows a greater activity in the area north of compound landslide although velocity is extremely low below 16 mm yr 1 this extremely slow movement revealed by interferometry is in agreement with other geological and geomorphological evidence such as the existence of speleothems and cemented breccias against the head walls of the trenches both deposits are indicative of a long period of discontinuity widening also undisturbed debris deposits covering ancient rock slides are indicative of very slow gravitational processes characterized by long dormant periods in addition a historical picture from 1898 shows nearly negligible change in the simas de partagat over this 112 yr period

martian high latitude permafrost depth and surface cover thermal inertia distributions 1 martian high latitudes have thermal properties consistent with an extensive high thermal inertia permafrost layer near the surface surface cover thermal inertias and permafrost depths at martian high latitudes 50 80 n s are derived from thermal emission spectrometer tes data and compared with previously published water ice depths determined from the mars odyssey neutron spectrometer mons the depth to the permafrost layer is correlated with surface cover thermal inertia albedo and latitude in general agreement with predicted trends of water ice stability comparison of permafrost depths with water ice rich layer depths derived from mons data displays good qualitative agreement although a divergence is present at greater burial depths this disparity may be due to the presence of hydrated minerals at shallow depths or a lower than expected permafrost thermal inertia corresponding with low water ice concentrations at greater depths surface cover thermal inertias are greater in the northern high latitudes than in the south and differences between these and previous results will have significant effects on the predicted depth of martian water ice stability several regions in the northern hemisphere display high surface cover thermal inertia associated with possible receding water ice deposits that are shallow enough to influence diurnal surface temperatures significant lateral and vertical heterogeneity in water ice distributions are present and the martian regolith is likely more complicated than can be described by simple two layered models and a single mode of water ice emplacement

development and recent activity of the san andres landslide on el hierro canary islands spain abstract extremely voluminous landslides with a long run out also known as megalandslides on oceanic volcanic islands are infrequent denudational processes on such islands at the same time they represent a major geological hazard that must be looked into to avoid negative consequences for the inhabitants of these islands their occurrence can be related to periods of intense seismo volcanic activity similar to that which occurred on el hierro island over 2011 2012 landslides on volcanic islands are studied using onshore and offshore geological geophysical and geomorphological records considering their unique triggering conditions e g lava intrusions eruptive vents magma chamber collapses previous work has pointed out similarities between specific cases of landslides on volcanic islands and deep seated gravitational slope deformations dsgsds which are typical in high mountain settings nevertheless the methodological approaches and concepts used to investigate dsgsds are not commonly applied on volcanic islands studies even though their use may provide new information about the development stage recent movements and future hazards therefore this approach for studying the san andres landslide sal on el hierro canary islands has been developed applying a detailed morphological field mapping an interpretation of digital elevation models structural measurements kinematic testing and a precise movement monitoring system the acquired information revealed a strong structural influence on the landslide morphology and the presence of sets of weakened planes acting as the sliding surfaces of the sal or secondary landslides within its body the presence of secondary landslides deep erosive gullies coastal cliffs and high on shore relative relief also suggests a high susceptibility to future landslide movement direct monitoring on the landslide scarps and the slip plane performed between february 2013 and july 2014 using an automated optical mechanical crack gauge with a precision of up to 10 2 mm detected creep movement in the order of 1 mm yr 1 with a persistent sinistral component as well as episodic horizontal and a subtle vertical movement this monitoring will continue in the future in order to verify the initial observations which instead of long term movement patterns could represent a landslide response to the period of an intense seismo volcanic activity during 2011 12

tectonic denudation and topographic development in the spanish sierra nevada 1 the denudation history of the rapidly uplifting western part of the spanish sierra nevada was assessed using apatite fission track aft ages and 10be analyses of bedrock and fluvial sediments major contrasts in the denudation history are recorded within the 27 km2 rio torrente catchment upland areas are characterized by low relief low slope angles and locally the preservation of shallow marine sediments which have experienced 2 km of denudation since circa 4 ma the minimum denudation rates of 0 4 mm yr 1 derived from aft also contrast with the slow medium term 104 years erosion rates 0 044 0 015 mm yr 1 estimated from 10be measurements at high elevations the local medium long term contrasts in denudation rates within the high sierra nevada indicate that much of the unroofing occurs by tectonic denudation on flat lying detachments in lower elevation parts of the catchment rapid river incision coupled to rock uplift has produced 1 6 km of relief implying that the rivers and adjacent hillslopes close to the edge of the orogen are sensitive to normal fault driven changes in base level however these changes are not transmitted into the low relief slowly eroding upland areas thus the core of the mountain range continues to increase in elevation until the limits of crustal strength are reached and denudation is initiated along planes of structural weakness we propose that this form of tectonic denudation provides an effective limit to relief in young orogens

detachment faults evidence for a low angle origin the origin of low angle normal faults or detachment faults mantling metamorphic core complexes in the southwestern united states remains controversial if sigma sub 1 is vertical during extension the formation of or even slip along such low angle normal faults is mechanically implausible no records exist of earthquakes on low angle normal faults in areas currently undergoing continental extension except from an area of actively forming core complexes in the solomon sea papua new guinea in light of such geophysical and mechanical arguments w r buck and b wernicke and g j axen proposed models in which detachment faults originate as high angle normal faults but rotate to low angles and become inactive as extension proceeds these models are inconsistent with critical field relations in several core complexes the rawhide fault an areally extensive detachment fault in western arizona propagated at close to its present subhorizontal orientation late in the tertiary extension of the region neither the wernicke and axen nor buck models predict such behavior in fact both models preclude the operation of low angle normal faults the authors recommend that alternative explanations or modifications of existing models are needed to explain the evidence that detachment faults form and operate with gentle dips

analysis of large seismically induced gravitational deformations imaged by high resolution cosmo skymed synthetic aperture radar using differential synthetic aperture radar interferometry dinsar on cosmo skymed constellation of small satellites for the mediterranean basin observation data we obtain an accurate and spatially continuous measure of the coseismic ground displacement due to the mw 6 3 l9aquila central italy earthquake we identify two local deformation patterns associated with long term gravitational mass movements and interpret the deformation mechanisms by integrating geological analysis and simple analytical modeling these subtle deformations the role of which in landscape evolution and earthquake induced hazard needs to be fully assessed may only be identified using high resolution dinsar

stress strain time numerical modelling of a deep seated gravitational slope deformation preliminary results abstract an analysis of the effects of creep on the development of a deep seated gravitational slope deformation dsgsd carried out by numerical modelling is described the slope rock mass evolution has been simulated applying different creep rheological models the studied dsgsd is located in the central italian alps val s giacomo it is characterised by three main scarps different sets of tensile trenches and counterscarps mapped during a detailed geomorphological survey the mechanical behaviour of the rock masses in terms of elasto plastic parameters has been defined on the base of laboratory and in situ tests in order to simulate this instability process a stress strain time numerical modelling has been performed by a finite difference numerical code fast lagrangian analysis of continua flac the effects of different constitutive model laws have been considered the visco elastic maxwell model the visco elastic burger model and the elasto visco plastic burger model the modelling has been performed simulating the melting of the ancient glacier starting from its maximum load because of the difficulty to determine rock mass creep parameters for each of the rheological models a sensitivity analysis has been performed varying the physical mechanical properties the visco elasto plastic model allows to underline the formation of shear surface showing a depth and a shape in good agreement with the morphologic features of the slope the only action of unloading due to glacier melting seems to be insufficient to generate deep critical surfaces which can be related with the formation of the dsgsd

quaternary catastrophic rock avalanches in the central apennines italy relationships with inherited tectonic features gravity driven deformations and the geodynamic frame abstract five cases of quaternary rock avalanches detached from carbonate mountain ridges in the central apennines are presented due to the large amount of rock masses involved the width of accumulation and detachment areas and the damming in the host environment the analysed rock avalanches can be considered as catastrophic rock slope failures sporadic events in a mountain region characterized by low elevation but where mountain ridges can have a relative elevation of up to 1 km above the lowermost valley floors the geological setting of tectonic structures that originated during the apennine orogenesis influenced rock avalanche characteristics determining the location and shape of detachment areas the kind of rock mass involved and the failure mechanisms two main types have been identified i forelimb rock slide avalanches frsa such as the lettopalena and mt arezzo rock avalanche which involved cenozoic heterogeneous sequences of carbonate ramp deposits detached from box shaped source areas according to a rock sliding mechanism and ii backlimb slide wedge rock avalanches bswra such as the campo di giove scanno and celano rock avalanches that detached from sub circular source areas carved on fault bounded ridges and involving meso cenozoic carbonate rocks with a combined sliding and rock wedge failure mechanism the campo di giove lettopalena and scanno rock avalanches originated from mountain ridges bounded by inactive fault zones and undergoing deep seated gravitational slope deformations dsgsds at the mountain scale these three rock slope failures are considered as isolated events of long lasting deformative processes featuring creep deformation gravity driven deformations firstly generated as a response to stacking processes and synchronous normal faulting during the neogene early pleistocene apennine tectonics in particular the caramanico fault system cfs and the genzana fault gf bordering the carbonate ridges from which the campo di giove and scanno rock avalanches originated respectively are here considered as backlimb collapse structures accommodating the passive uplift and deformation of positive tectonic structures gravity driven deformations persisted during the post early pleistocene dome like uplift of the whole apennine region the regional uplift created the first order 200 km topographic wave length of the belt i e a periodic loading which has been balanced by the deflection of the apennine crust and lithosphere on the contrary shorter topographic wave lengths inherited from former thrusting and synchronous normal faulting determined local isostatic imbalances bearing a large potential for the mature development of dsgsds on mountain ridges favoured also by lateral unloading due to linear erosion and increase of topographic stress thus a cause effect relationship is hypothesized between the geodynamic evolution of the belt and mountain sized gravity driven deformations including large rock slope failures

the contribution of landslides to landscape evolution in europe abstract after a review of some analytical and conceptual models of slope evolution with the intervention of mass movements a proposal is made of a series of indicators for the quantitative description of landscape evolution in relation to mass movements the ratio between landslide mobilisation rate and downwearing rate is proposed as a quantitative measure of the significance of mass movements in landscape evolution a subdivision of european regions with respect to their susceptibility to landsliding as a process of landscape evolution is proposed the role of landsliding for the evolution of landscape in some regions is described the data presented show that landsliding may in some cases be the main contributor to landscape change

seismotectonics of the el asnam earthquake the mechanism of the el asnam earthquake of 10 october 1980 ms 7 2 the strongest recorded in northwestern africa is compatible with a convergence between the african and european plates the thrust is also consistent with field observations and with long period data from the global network aftershocks cluster around the fault trace with a maximum depth of 12 km maximum vertical displacement is 6 m and there is some left lateral motion the fault trace of the 1954 earthquake at beni rached was also reactivated

discovery controls and hazards of widespread deep seated gravitational slope deformation in the etsumi mountains central japan deep seated gravitational slope deformation dsgsd is a largely unnoticed but important long term mass wasting process that may result in catastrophic failure of mountain slopes manifested by small topographic irregularities such as ridge parallel scarps and linear depressions it has been predominantly reported in alpine landscapes above timber lines on the basis of area wide high resolution topographic data acquired by light detection and ranging lidar surveys we here show that 96 of existing gravitational scarps have been hidden under forest canopies in the etsumi mountains central japan the scarps are surprisingly widespread over the mountains with a mean line density of as large as 0 87 km km2 our analyses of the scarp distribution suggest that uphill facing scarps are primary geomorphic signals of dsgsd with a destabilized rock mass larger than 105 m2 whereas downhill facing scarps principally occur in response to more localized slope deformation in terms of controls topography is by far the most influential factor in triggering and promoting dsgsd despite the m 7 5 earthquake in 1891 impact of large local earthquakes proves to be not very strong comparison with preexisting landslide maps further suggests that dsgsd and large scale landslide are not different slope processes but represent different stages of the same process our results highlight limitation of aerial photograph interpretation in forest covered mountains and the need for lidar assisted mapping for deeper understanding of this long term process and interactions between surface and tectonic processes

mass movements related to tectonics in the aspromonte massif southern italy abstract geomorphic and structural studies have been carried out on the headwaters of vallone colella torrent in an area intensely affected by mass movement phenomena on the aspromonte massif of southern italy rock types outcropping in the area are mostly gneiss and granitoids with subordinate presence of metarenites phyllites and biotite schists all lithologies experienced low grade metamorphism as indicated by petrographic analysis structural surveys performed at macroscopic and mesoscopic scale allowed recognition of several sets of discontinuities related to different deformation events the upper reaches of vallone colella torrent present a large active landslide zone the debris materials of which feed the debris flows along the drainage system towards the main valley mass movement phenomena are both shallow and deep seated the latter are limited to a sector of the study area while shallow processes are present throughout the landslide zone some considerations of the relationship between tectonics and mass movement are presented with particular reference to the presence of a large scale downthrown wedge bounded by structural surfaces on both sides of the valley located in the same area affected by deep seated phenomena

tectonic control of complex slope failures in the ameka river valley lower gibe area central ethiopia implications for landslide formation abstract even though major faults represent important landslide controlling factors the role the tectonic setting in actively spreading rifts plays in the development of large complex landslides is seldom discussed the ameka complex landslide area is located on the eastern scarp of the gibe gorge approximately 45 km to the west of the main ethiopian rift and 175 km to the southwest of addis ababa investigation of the complex landslide failures required a combination of satellite and airborne data based geomorphology geological field survey complemented with structural analysis radiocarbon geochronology and vertical electric sounding the obtained observations confirmed the multiphase evolution of the landslide area we have documented that apart from climatic and lithological conditions the main triggering factor of the ameka complex landslide is the tectonic development of this area the e w extension along the nne ssw trending main ethiopian rift is associated with the formation of numerous parallel normal faults such as the gibe gorge fault and the almost perpendicular scissor faults the geometry of the slid blocks of coherent lithology have inherited the original tectonic framework which suggests the crucial role tectonics play in the fragmentation of the compact rock masses and the origin and development of the ameka complex landslide area similarly the main scarps were also parallel to the principal tectonic features the local tectonic framework is dominated by faults of the same orientation as the regional structures of the main ethiopian rift such parallel tectonic frameworks display clear links between the extension of the main ethiopian rift and the tectonic development of the landslide area the ameka complex landslide developed in several episodes over thousands of years according to the radiocarbon data the last of the larger displaced blocks representing only 2 of the total area most likely slid down in the seventh century ad the main scarps namely the high scarps in the western part are unstable over the long term and toppling and falling type slope movements can be expected here in the future

crevice type caves as initial forms of rock landslide development in the flysch carpathians crevice type caves formed along joints are very common in the polish flysch carpathians more than 600 have been recorded the caves represent accessible parts of the widened cracks which are basic initial forms of development of deep seated rock landslides structural features of four selected caves situated in different parts of the carpathians were studied in order to determine relations between joint systems and landslide formation the studies prove that the main rock scarps often represent effects of earlier propagation of the cracks cutting surfaces due to loading and unloading shearing stress the cracks are structural forms developed along joints or faults the cutting surfaces represented by cracks caves develop a long time before the main gravitational mass movements whereas the sliding surfaces shearing zones are formed or significantly modified ad hoc during the gravitational transport of rock masses occurrence of the deep initial cracks causes modification of shape of the sliding surfaces which are noncircular the mountain slopes cut by many cracks are permanently developed thus the periodic increase of activity of external factors floods downpours earthquakes etc leads to common formation of the landslides earlier prepared by crack development this model of slope evolution enables us to interpret the occurrence of the landslide phases in the holocene during which increasing of frequency of the landslides is observed

gravitational and tectonic stress states within a deep seated gravitational slope deformation near the seismogenic periadriatic line fault abstract the role of tectonic horizontal stresses in activating deep seated gravitational slope deformations dsgsd has rarely been studied we applied a new numerical technique for determining the present day stress states within a large dsgsd situated near the periadriatic line fault pal in the eastern alps the stress states were calculated from three dimensional displacements of the sinistral obir fault conjugated to the dextral pal fault which also forms the upper dsgsd detachment plane the analysed fault displacements occurred in two distinct activity phases associated with the elastic rebound along i the obir fault in the summer of 2014 and ii the core of the pal fault in the winter of 2014 2015 these periods were synchronous with the periods of increased local seismicity the results brought an insight into a possible causative link between horizontal tectonic stresses and dsgsds activation we observed that transient dextral transpressions and dextral transtensions opposing to the general fault kinematics associated to the elastic rebound had a potential to destabilize the dsgsd at the micrometre level the applied stress tensor calculation although restricted only to shallow near surface conditions is a reliable method that can reveal stress states almost in the real time

analysis of the deep seated gravitational slope deformations over mt frascare central italy with geomorphological assessment and dinsar approaches abstract a quantitative and innovative dgsd deep gravitational slope deformation assessment method that used integrated remote sensing was tested in the central apennine mountain range italy the movement rate was calculated for selected test areas using the differential sar interferometry small baseline subset sbas technique the selected test areas were previously identified by interpreting both aerial photos and using 32 ers radar images taken between 1993 and 2000 more than 15 cm of cumulative surface displacement occurred across the podalla dgsd along the satellite line of sight los moreover the displacement time series showed non linear deformation rates which included periods of accelerated movement correlated with strong rainfall the high estimated podalla dgsd activity indicates that this type of study should be conducted to monitor the evolution of this phenomenon in addition the dinsar movement rate can be used to improve mapping and identify dgsds in specific landscapes

laser scanning based recognition of rotational movements on a deep seated gravitational instability the cinque torri case north eastern italian alps abstract the cinque torri group cortina d ampezzo italy is an articulated system of unstable carbonatic rock monoliths located in a very important tourism area and therefore characterized by a significant risk the instability phenomena involved represent an example of lateral spreading developed over a larger deep seated gravitational slope deformation dsgsd area after the recent fall of a monolith of more than 10 000 m 3 a scientific study was initiated to monitor the more unstable sectors and to characterize the past movements as a fundamental tool for predicting future movements and hazard assessment to achieve greater insight on the ongoing lateral spreading process a method for a quantitative analysis of rotational movements associated with the lateral spreading has been developed applied and validated the method is based on i detailed geometrical characterization of the area by means of laser scanner techniques ii recognition of the discontinuity sets and definition of a reference frame for each set iii correlation between the obtained reference frames related to a specific sector and a stable external reference frame and iv determination of the 3d rotations in terms of euler angles to describe the present settlement of the cinque torri system with respect to the surrounding stable areas in this way significant information on the processes involved in the fragmentation and spreading of a former dolomitic plateau into different rock cliffs has been gained the method is suitable to be applied to similar case studies

geomorphological hazards related to deep dissolution phenomena in the western italian alps distribution assessment and interaction with human activities abstract deep dissolution affects great part of soluble rocks e g gypsum and anhydrite of the western italian alps the related superficial phenomena sinkholes gravity induced processes and a local worsening of geomechanical rock properties are not limited to typical karsts landscape and cause slope instability also affecting populated sites and infrastructures the paper aims to describe general characteristic of dissolution phenomena to interpret their conditioning factors and evolutionary stages and to assess possible hazards due to their superficial effects the search for evidences of deep dissolution leads to the selection of representative sites in the central part of the western italian alps piemonte and valle d aosta region detailed geological and geomorphological studies have been used to classify the selected sites by type size and variable state of activity very different evolutionary stages of dissolution phenomena have been interpreted by comparison of case studies some are early embryonic others are more evolved up to typical sinkholes or even remodelled by other phenomena some cases show an extreme complexity in the interactions between corrosion phenomena and other geomorphic processes slope deformations from one side and karst fluvial and glacial phenomena to the other a wide range of movement rates on slope instabilities induced by deep dissolution have been estimated by topographic and geomorphic data geochemical data on removed rocks by dissolution indicate 0 4 mm year values for local subsidence historical and technical data indicate low frequency of major dissolution induced collapses but highlight widespread damages to tunnels roads and buildings especially along slopes

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

deep seated failure propagation in a fractured rock slope over 10 000 years the la clapiere slope the south eastern french alps abstract the la clapiere area tinee valley alpes maritimes france is a typical large complex unstable rock slope affected by deep seated gravitational slope deformations dgsd with tension cracks scarps and a 60 106 m3 rock slide at the slope foot that is currently active the slope surface displacements since 10 ka were estimated from 10be ages of slope gravitational features and from morpho structural analyses it appears that tensile cracks with a strike perpendicular to the main orientation of the slope were first triggered by the gravitational reactivation of pre existing tectonic faults in the slope a progressive shearing of the cracks then occurred until the failure of a large rock mass at the foot of the slope by comparing apertures variations and changes in direction between cracks of different ages three phases of slope surface displacement were identified 1 an initial slow slope deformation spreading from the foot to the top characterized by an average displacement rate of 4 mm yr 1 from 10 5 6 ka bp 2 an increase in the average displacement rate from 13 to 30 mm yr 1 from the foot to the middle of the slope until 3 6 ka bp and 3 development of a large failure at the foot of the slope with fast displacement rates exceeding 80 mm yr 1 for the last 50 years the main finding of this study is that such a large fractured slope destabilization had a very slow displacement rate for thousands of years but was followed by a recent acceleration the results obtained agree with several previous studies indicating that in situ monitoring of creep of a fractured rock slope may be useful for predicting the time and place of a rapid failure

the relationship between seismic deformation and deep seated gravitational movements during the 1997 umbria marche central italy earthquakes abstract this paper re evaluates the origin of some peculiar patterns of ground deformation in the central apennines observed by space geodetic techniques during the two earthquakes of the colfiorito seismic sequence on september 26th 1997 the surface displacement field due to the fault dislocation as modelled with the classic okada elastic formulations shows some areas with high residuals which cannot be attributed to non simulated model complexities the residuals were investigated using geomorphological analysis recognising the geologic evidence of deep seated gravitational slope deformations dsgsd of the block slide type the shape and direction of the co seismic ground displacement observed in these areas are correlated with the expected pattern of movement produced by the reactivation of the identified dsgsd at least a few centimetres of negative line of sight ground displacement was determined for the costa picchio mt pennino and mt prefoglio areas a considerable horizontal component of movement in the costa picchio dsgsd is evident from a qualitative analysis of ascending and descending interferograms the timing of the geodetic data indicates that the ground movement occurred during the seismic shaking and that it did not progress appreciably during the following months this work has verified the seismic triggering of dsgsd previously hypothesized by many researchers a further implication is that in the assessment of dsgsd hazard seismic input needs to be considered as an important cause of accelerated deformation

slope instability and sagging reactivation at maratea potenza basilicata italy abstract the present work shows results collected through a long term monitoring on slope movements in the maratea valley potenza italy the investigated area shows large scale gravitational phenomena and sagging type morphology that have been well described in previous works electronic distance meter edm measurements were first taken in 1983 and from these it would appear that since about 1991 there has been an acceleration in the movement occurring in the upper part of the valley where sagging is located and which was previously motionless seismic and rainfall series for the last 20 years have been examined the data collected show that this sagging destabilisation could not be related to rainfall and recent seismic activity the latter reactivating later in 1998 global positioning system gps data on a network including benchmarks located outside of the landslide area and comparison with edm data indicate that movement affected the surrounding mountain slopes widening the valley and destabilising the sagging thus suggesting a relationship between the sagging and tectonic activity

deep seated gravitational slope deformation large scale rock failure and active normal faulting along mt morrone sulmona basin central italy geomorphological and paleoseismological analyses abstract active faulting is one of the main factors that induce deep seated gravitational slope deformations dgsds in this study we investigate the relationships between the tectonic activity of the nw se normal fault system along mt morrone central apennines italy and the evolution of the associated sackung type dgsd the fault system is considered to be the source of m 6 5 7 earthquakes our investigations have revealed that the dgsd began to affect the mt morrone sw slope after the early pleistocene this was due to the progressive slope instability arising from the onset of the younger western fault with the older eastern fault acting as the preferred sliding zone paleoseismological investigations based on the excavation of slope deposits across gravitational troughs revealed that the dgsd was also responsible for the displacement of late pleistocene holocene sediments accumulated in the sackung troughs moreover we observed that the investigated dgsd can evolve into large scale rock slides therefore as well as active normal faulting the dgsd should be considered as the source of a further geological hazard overall our approach can be successfully applied to other contexts where active normal faults control the inception and evolution of a dgsd

is phase a relevant to the earth s mantle abstract dense hydrous magnesium silicates dhms such as phase a mg 7 si 2 o 8 oh 6 are potential hosts for water in the earth s mantle previous work has delineated the stability field of phase a pha coexisting with clinoenstatite cen and forsterite fo in the system mgo sio 2 h 2 o msh in this study the effects of the presence of magnesite mc diopside di and pyrope py on the stability of coexisting pha cen fo have been determined in msh the breakdown reaction pha cen fo h 2 o was bracketed between 720 and 740 c at 7 gpa between 800 and 820 c at 8 gpa and between 860 and 880 c at 9 gpa at 10 gpa pha cen transforms to a clinohumite ch bearing assemblage between 920 and 940 c which in turn dehydrates between 940 and 960 c to fo v at higher pressures pha becomes unstable relative to phase e another dhms kanzaki 1991 addition of carbonate to msh changes the breakdown reaction to pha cen mc fo v where v is an h 2 o co 2 fluid at 8 gpa this reaction occurs between 800 and 850 c indistinguishable from the position of the co 2 free reaction in msh in the presence of diopside in the cao mgo sio 2 h 2 o system the reaction pha en ss fo di ss h 2 o occurs between 700 and 730 c at 8 gpa where en ss and di ss are ca poor and ca rich pyroxene solid solutions respectively in the pyrope containing assemblage in the mgo al 2 o 3 sio 2 h 2 o system the pha bearing assemblage reacts to form ch between 740 and 760 c at 8 gpa the ch bearing assemblage dehydrates to fo py v between 800 and 830 c at 8 gpa in the system mgo feo sio 2 h 2 o with molar mg mg fe 0 90 the reaction pha cen ss ch v occurs at ss ch fo v reaction occurs between 850 and 900 c in no case did the presence of additional components such as cao feo al 2 o 3 or co 2 or the additional phases diopside magnesite or pyrope stabilize the hydrous phases pha or ch to significantly higher temperatures therefore pha will not be a stable phase in lherzolite assemblages under normal geothermal gradients in the mantle in the interior of subducting slabs temperatures may be sufficiently low that assemblages containing pha may be stable to pressures greater than 10 gpa allowing pha to transport h 2 o to the deeper mantle it is more likely that the higher pressure phase e will be stabilized instead

deep seated gravitational slope deformations in the highest parts of the czech flysch carpathians evolutionary model based on kinematic analysis electrical imaging and trenching deep seated gravitational slope deformations dsgsds played an important role during the quaternary evolution of mountain ridges formed by anisotropic flysch rocks of the outer western carpathians owc four dsgsd affected ridges in the highest part of the czech sector of the owc have been subjected to multidisciplinary investigation involving mapping structural and kinematic analysis geoelectrical imaging trenching and dating all the studied dsgsds are strongly predisposed by regional structural fabric given by the intersection of bedding planes joint sets and faults performed research suggests high diversity of mechanisms leading to the origin of individual dsgsds the area of a single dsgsd can be affected by various types of movements such as sackung lateral spreading toppling or incipient sliding electrical imaging and trenching revealed that besides these mechanisms anisotropic flysch massifs formed by thick bedded sandstones are strongly exposed to subsurface opening of air filled voids related to widened crevices such a process is driven by deep seated creep and translational sliding of sandstone beds upon plastic claystones whose strength has been reduced to residual values of the angle of internal friction performed radiocarbon and osl dating revealed that some of the studied dsgsds originated in the holocene period particularly in the atlantic and subboreal chronozones

development of deep seated gravitational slope deformation on a shale dip slope observations from high quality drill cores abstract we analyzed high quality drill cores with 100 recovery drilled into a gravitationally deformed dip slope of a shale dominated sequence of sediments in japan the slope had undulating surfaces but no well defined landslide scarps suggesting that parts of the slope had undergone gravitational deformation but had not completely separated from the surrounding bedrock the gravitational deformation of shale and sandstone is characterized by disintegration and brecciation of sediments and the formation of pulverized zones with poorly developed planar structures jigsaw like structures and fracture openings shear zones are distributed intermittently within the slope but have not merged discernably into a through going master sliding surface incipient landslide shear zones form openings within coherent rock by shearing along bedding with these shear zones potentially developing downward in a stepwise manner which may be related to stress redistribution induced by river incision

movements detection of deep seated gravitational slope deformations by means of insar data and photogeological interpretation northern sicily case study we investigated the northern central portion of sicily region southern italy using aerial photographs and synthetic aperture radar sar data obtained by ers1 and ers2 satellites this area shows a geological structural setting generated by the tectonic superposition of apenninic maghrebian carbonatic structures on terrigenous deposits such a structural setting favoured the development of large scale gravity driven phenomena known in the geological literature as deep seated gravitational slope deformations that are mostly responsible for the landscape evolution of the whole area morphological evidences such as landslides sacking or rock flow lateral spread and block slide can be detected from photogeological analysis in order to understand the temporal behaviour and spatial distribution of such deformations we applied the interferometric sar insar technique interferograms show fringe patterns spatially coinciding with some of the large scale gravitative phenomena previously identified by means of aerialphoto analysis the comparison between photogeological data and insar results allows delimiting the active sectors in the study area

structural control and types of movements of rock mass in anisotropic rocks case studies in the polish flysch carpathians abstract types of gravitational movements in the flysch carpathians are related to tectonic and lithologic anisotropy of rock massifs this article presents the main types of mass movements in the highly anisotropic flysch massifs lateral spreading and rock flow topple translational rotational and compound sliding and complex type of mass movements which are illustrated by chosen forms described using structural analysis joints faults and other structural planes orientation topple is the typical mass movement for double ridges and top trenches e g gaworzyna in the beskid s decki mts translational landslides with flat structural sliding surfaces typical for shallow forms can develop along bedding planes e g duszatyn western bieszczady mts as well as along joints opuszna gorce mts and fault planes rzeki gorce mts currently used classification of the structural landslides is applied only to translational landslides shearing zones of deep seated landslides are composed of structural sections of joints faults bedding planes and shearing elements consequently most of the carpathian landslides have developed as compound type with non circular sliding zones representing complex movements combined with various types of displacement rotation translation and or topple purely rotational movements with circular failure typical for isotropic material have developed in the flysch where thick bedded hard sandstones are underlain by plastic shales e g mt kostrza in the beskid wyspowy mts the influence of anisotropy of these rocks on sliding surface is significantly reduced and plastic type rocks stimulate rock flow development which is usually later transformed into complex landslides with predominant rotational movement e g rotational landslide with topple and flow elements on mt muronka in the beskid l ski mts compound landsliding on mt lubon wielki beskid wyspowy mts represents an antithetic rotational slide with topple and rotational type movements

quaternary tectonics and large scale gravitational deformations with evidence of rock slide displacements in the central apennines central italy eight cases of large scale gravitational movements with evidence of rock slide type displacements evolving close to quaternary faults have been analysed in the central apennines geomorphological and structural surveys have defined the relationship between the gravitational displacements and the tectonically controlled modifications of the landscape the evolution of all the investigated cases has been conditioned by the presence of fault planes located along the mountain slopes in most cases mt cefalone cima della fossa villavallelonga casali d aschi gioia dei marsi the faults played or are playing a primary role in increasing the local relief and their activity represents the main geomorphic factor conditioning the gravitational movements this kind of relationship has been observed along mountain slopes bordering depressions which have not been drained for most of their geomorphic history or have been characterised by an evolution of the hydrographic network that has been conditioned only by the local tectonic subsidence in such cases the gravitational movements develop in the footwalls of the faults in other cases fiamignano pescasseroli the faults have played a passive role since they only bound the sliding masses and coincide with the surficial expressions of the sliding planes therefore the gravitational displacements develop in the hangingwall of the faults the evolution is conditioned by the incision of the hydrographic network in response to regional quaternary uplift the illustrated case studies provide a wide range of examples of the gravitational response of slopes to the modifications of the landscape due to linear and areal tectonics the identification of the geomorphic traces of the large scale gravitational movements along fault controlled mountain fronts has implications for hazard particularly for the evolution of the displacement the quantitative analysis of the vertical displacements and data on the characteristics of the surface breaking during historical earthquakes demonstrate that along fault offsets strongly increases where the unstable large scale rock masses are located therefore the large coseismic vertical offset may represent a major problem for the displacement of utilities and may represent a potential cause for the sudden and catastrophic evolution of the gravitational movement

interpretation of radon anomalies in seismotectonic and tectonic gravitational settings the south eastern crati graben northern calabria italy the study area is located in the south eastern part of the crati valley northern calabria italy which is a graben bordered by n s trending normal faults and crossed by nw se normal left lateral faults numerous severe crustal earthquakes have affected the area in historical time present day seismic activity is mainly related to the n s faults located along the eastern border of the graben in this area much seismically induced deep seated deformation has also been recognised in the present paper radon concentrations in soil gas have been measured and compared with a lithology b quaternary faults c historical and instrumental seismicity and d deep seated deformation the results highlight the following a there is no evidence of a strong correlation between lithology and the radon anomalies b a clear correlation between the n s geometry of radon anomalies and the orientation of main fault systems has been recognised except in the southernmost part of the area where the radon concentrations are strongly affected by the superposition of the n s and the nw se fault systems c epicentral zones of instrumental and historical earthquakes correspond to the highest values of radon concentrations probably indicating recent activated fault segments in particular high radon values occur in the zones struck by earthquakes in 1835 1854 and 1870 d deep seated gravitational deformation generally coincides with zones characterised by low radon concentrations in the studied area the anisotropic distribution of radon concentrations is congruent with the presence of neotectonic features and deep seated gravitational phenomena the method used in this study could profitably contribute towards either seismic risk or deep seated gravitational deformation analyses

paraglacial gravitational deformations in the sw alps a review of field investigations 10be cosmogenic dating and physical modelling catastrophic deep seated landslides dsl are generally considered to be the result of large slope deformations also known as deep seated gravitational slope deformation dsgsd this paper aims to build a synthesis of multiple studies made in the tinee valley southern french alps to assess the geometrical kinematical mechanical and chronological relationships between these two gravitational processes at the scale of the valley data issued from geological geomorphological and 10be dating indicate a clear geometrical link between dsgsd and dsl occurring at the base of the slope and suggest that gravitational slope evolution began after the glacial retreat 13 ka bp this is supported by the example of the well documented la clapiere slope a continuous evolution process is characterized geometrically and temporally from geomorphic observations and analogue modelling coupling structural geomorphological physical and chronological studies allowed us to propose a four dimensional 4d deformation model mechanically correlated with progressive failure concept the validity and variability of this reference site are discussed at the valley scale taking isola and le pra slope deformation as examples it allows a rough estimation of the state of slope deformation at the valley scale to be constructed and the slope evolution with time to be considered this 4d model could then be considered as a reference for other deep seated gravitational slope deformations in comparable alpine valleys

step like displacements of a deep seated gravitational slope deformation observed during the 2016 2017 seismic events in central italy abstract deep seated gravitational slope deformations are characterized by low deformation rates although they can experience partial collapse phases or more rapid movements especially in presence of active tectonic structures in the central italy considering the high seismicity rate seismic activity must be considered to be an important trigger of deep slope movements we aim to contribute to the research in this field by reporting the results of a monitoring program on a deep seated gravitational slope deformation in this region that involves marly calcareous rocks we documented the pre earthquakes evolution of the phenomenon and measured its displacements during the seismic sequence in 2016 and 2017 in central italy which largest events were mw 5 0 to 6 5 a multidisciplinary approach that combines a field geomorphological survey installation of permanent gps stations and insar elaborations was adopted for this study the average ground motion rate of the slope deformation before the earthquakes was very low on the other hand gps and insar recorded significant step like movements one to ten times higher than the normal activity rate triggered by the mw 5 0 to 6 5 earthquakes in detail the movement mainly depended on the magnitude of the earthquake and the distance from the epicenter and only secondarily on the number of larger magnitude earthquakes on a given day in conclusion we furnished monitoring data on the activity rate of a deep seated gravitational slope deformation in seismic context we indicated two sectors of the investigated deformation that resulted more unstable and we proved that the combination of insar and gps data is a useful monitoring system for earthquake activated slow moving slope instabilities

geomorphological research of large scale slope instability at machu picchu peru a multidisciplinary approach has been adopted to study the slope movements and landscape evolution at the archaeological site of machu picchu and its immediate surroundings the basic event in the paleogeomorphological evolution of the area was the large scale slope movement which destroyed the originally higher ridge between mt machupicchu and mt huaynapicchu within remnants of that primary deformation several younger generations of slope movements occurred the laboratory analyses of granitoids revealed highly strained zones on the slopes of mt machupicchu which strongly affect the largest slope deformation the borders of the largest slope deformation are structurally predisposed by the existence of fault zones the majority of various types of slope movements on the so called front slope e facing and back slope w facing are influenced by the alignment between topography and joints along with slope movements fluvial erosion and tectonic disturbance of the rocks have been affecting the evolution of the landscape a monitoring network for dilatometric and extensometric measurements was used to detect the present day activity of rock displacements within the archaeological site in addition to standard mapping of surface hydrogeological phenomena eleven express slug tests were conducted to verify the infiltration potential of precipitation the results of these surveys indicate that recent large scale slope movement as suggested by some previous studies is doubtful and the detected movements can be explained by individual movements of rock blocks or several other mechanisms including sinking of archaeological structures subsurface erosion and annual changes in the water content of the soils

insights on the kinematics of deep seated gravitational slope deformations along the 1915 avezzano earthquake fault central italy from time series dinsar abstract among the causes of deep seated gravitational slope deformations dgsd the most important is relief energy which is closely related to the intensity of the active tectonic deformations either at the regional scale or at the scale of a single active fault we analyzed some examples of dgsd from the eastern border of the fucino basin in the central apennines where extensional tectonics has been active since the late pliocene photogeological and field geomorphological analysis was performed to identify landforms typically associated with dgsd such as counterslope scarps double crests trenches and bulging slopes these features are located on a mountain range at less than 1 km from the causative fault of the 1915 avezzano earthquake we used the sbas differential sar interferometry technique to measure the slow movements of the surface and calculated differential vertical and horizontal ground velocities of 2 4 mm yr 1 during the period spanning from 1992 to 2001 the quantitative information on the kinematics of the deformation provided some inferences on the different processes responsible for the evolution of the observed dgsd the displacement time series shows non linear deformation trends at some locations possibly correlated with a strong meteorological event we speculate that dgsd in this area are normally subject to slow deformation and that sudden slip along sliding surfaces observed in excavations may sporadically be triggered off by extreme meteorological or seismic events evidence of catastrophic collapse of previous dgsd along the same mountain slope reinforce this hypothesis

forecasting landslide hazard by the 3d discrete element method a case study of the unstable slope in the lushan hot spring district central taiwan abstract catastrophic landslides and related phenomena are commonly facilitated by the subtropical climate with frequent typhoons and recurrent earthquakes in taiwan s mountainous areas one area susceptible to potentially catastrophic landslides is located at lushan in central taiwan which is famous for its hot springs and tourism the northern slope above the hot spring district slips gradually and frequently due to heavy rainfall for safety reasons the slip affected area has been under constant borehole monitoring by government agencies and a controversial public debate has arisen over permanent evacuation of the hot spring district in this study we attempt to simulate possible scenarios of catastrophic slope failure using slip geometries derived from the monitoring data and assess potential landslide impact areas by a discrete element method using the pfc3d code in the worst case scenario the lushan hot spring district is predicted to be destroyed by debris in 20 s besides the planned regional emergency refuge is rapidly jeopardized by flooding resulted from landslide dammed lakes this study addresses catastrophic slope failure under heavy rainfall conditions given a range of friction coefficients and varied continuity of the failure surfaces it is noted that the pfc3d code has limitations in modeling all complex mechanisms of landslide particularly in modeling loss of material shear strength due to increases in pore pressure nevertheless the numerical simulation results by the 3d discrete element method provide scenario based runout paths particle velocities and landslide affected areas which are useful information for decision support and future landslide hazard assessment

mass rock creep and landsliding on the huangtupo slope in the reservoir area of the three gorges project yangtze river china the huangtupo slope is one of the most noted large scale slopes with geologic hazards that cause problems related to the residential safety of immigrants in the reservoir area of the three gorges project yangtze river china the gravitational process blended with tectonic deformation large scale covering of loose debris and long term surficial mass movement complicates the huangtupo slope and gives rise to a lack of consensus on the slope nature and stability characterization of the structural geometry of the slope deformation and reconstruction of its development history are believed to be pivotal in understanding what has happened and what will happen to the slope based on a thorough field investigation combined with an electrical resistivity survey a three stage model involving mass rock creep primary landsliding partial reactivation is proposed the first stage follows the incision of the yangtze river along the axes of the guandukou syncline when huangtupo experienced long term gravitational deformation referred to as mass rock creep mass rock creep in the huangtupo slope can be classified as two basic processes toppling and deep seated creep toppling mainly occurs on the exterior part of the slope and is characterized by inclination sliding and segmentation of brittle deformation of cleavage rocks deep seated creep occurs predominantly in the interior part of the slope and brittle ductile flow folding accompanying low angle shearing is its representative deformation a primary large scale landslide occurred in the second stage as a subsequence of previous mass rock creep the landslide was ca 4 107 m3 in volume with elevations of 640 m a s l at the head and of 80 m a s l at the foot significant evidence for the landslide is the variation of attitudes of structural foliation and lineation among outcrops in the slope the last stage began subsequent to the original sliding surficial and partial reactivation on the huangtupo landslide plays a leading role in this stage two sliding events in this area in 1995 were ascribed to the partial reactivation mainly due to rainfall water level fluctuation of the yangtze river as well as human activity it was suggested that analogous failures in 1995 would continue on the huangtupo landslide and become even more frequent under the combined effect of human activity and reservoir filling

influence of structural framework on mountain slope deformation in the maiella anticline central apennines italy abstract relationships between tectonic framework and gravity driven phenomena have been investigated in an area of the central apennines italy characterised by high relief the north south half dome shaped maiella anticline lies in the easternmost part of the apennine fold and thrust belt its backlimb is bordered by the caramanico fault a normal fault with a maximum downthrown of about 3 5 km that separates the western slope of the maiella massif from the caramanico valley the southwestern maiella area is affected by deep seated gravitational slope deformation indicated by major double crest lines down hill and up hill facing scarps a pattern of crossing trenches bulging at the base of slopes and the presence of different types of landslide and talus slope deposits the onset and development of deep seated gravitational slope deformations and the location of quaternary massive rockslope failures have been strongly influenced by the structural framework and tectonic pattern of the anticline deep seated gravitational slope deformation at mt macellaro mt amaro ridge has developed along the maiella western reverse slope in correspondence with the anticline axial culmination it is bordered at the rear by a nnw sse oriented dextral strike slip fault zone and has an e w direction of rock mass deformation closer to the southern plunging area of the anticline gravity driven phenomena show instead a n s and nw se direction influenced by bedding attitude 3d topographic models illustrate the relationship between deep seated gravitational slope deformation and massive rockslope failures the campo di giove rock avalanche a huge quaternary failure event was the result of an instantaneous collapse on a mountaine slope affected by a long term gravity driven deformation

large landslides and their effect on sediment flux in south westland new zealand landslides and runoff are dominant erosional agents in the tectonically active alpine south westland area of new zealand characterized by high uplift rates and extreme orographic precipitation despite a high density of shallow debris slides and flows the geomorphic imprints of deep seated bedrock failures are dominant and persistent over 50 large 1k m 2 landslides comprising rock slide avalanches complex rotational and rock block slides wedge failures and deep seated gravitational slope deformation were detected on air photos and shaded relief images major long term impacts on alpine rivers include 1 forced alluviation upstream of landslide dams 2 occlusion of gorges and triggering of secondary riparian landslides and 3 diversion of channels around deposits to form incised meandering gorges remnants of large prehistoric i e pre 1840 landslide deposits possibly represent the low frequency in terms of total area affected yet dominant end of the spectrum of mass wasting in the western southern alps this is at odds with high erosion rates in an active erosional landscape large landslides appear to have dual roles of supplying and retaining sediment the implications of these roles are that 1 previous models of shallow landslide derived sediment flux need to be recalibrated and 2 geomorphic effects of earthquake induced landsliding may persist for at least 10 2 years copyright 2005 john

evolution of a large landslide in the high himalaya of central nepal during the last half century episodic and catastrophic landslides are considered to be one of the main sources of sediment in the steep mountainous landscapes of the himalayas however the evolution of a single landslide through time and its contribution to erosional processes remain poorly constrained in this study we focus on a single large 0 5 km2 landslide in a small catchment on the southern flank of the annapurnas in nepal the khudi valley in order to quantify its importance in the overall erosion of this steep himalayan catchment the evolution of the saituti landslide has been continuously monitored by remote sensing for the past 46 years during that period the saituti landslide displayed sustained activity such that the area of the landslide scar increased by a factor of 4 this retrogressive failure a consequence of several sporadic flank and crown collapses has not been continuous rather acceleration phases have alternated with more quiescent periods simultaneously the upper edge moved upward by 900 m based on field evidence from recent activity such as scarps and open tension cracks above the landslide and on an analysis of slope angles at least the next 500 m is expected to fail volume losses within the landslide were estimated from differences between digital elevation models dems and from changes in landslide area using a calibrated power law relationship between landslide area and volume corresponding landslide induced erosion rates at the scale of the whole khudi catchment were found to be 2 6 0 9 mm y for the past half century those rates are similar to denudation rates obtained from sediment load measurements between 1999 and 2004 those results along with the lack of other major landslides in the valley for the last 46 years suggest that the saituti landslide plays a dominant role in the modern erosion of the high himalayan khudi catchment for the last years and possibly for the past few decades we propose that continuous and sustained activity of a few major landslides over the past few decades might represent a significant contribution to the erosion of the high himalayan range this long lasting landslide induced erosion should be taken into account when interpreting suspended load measurements results from provenance analysis or cosmogenic nuclides in river sand such processes should also be included in landscape evolution models when annual to secular problems are explored

the role of graphite layers in gravitational deformation of pelitic schist abstract deep seated landslides in pelitic schists are common in many countries but are poorly investigated and understood in this study we present the first detailed examination and modelling of landslide mechanisms in these materials we found that pelitic schist commonly contains black graphite rich layers on a scale of millimeter to centimeter thickness that are typically weaker than neighboring layers by examining microscopic textures in borehole samples obtained from landslide masses of pelitic schist we find that ductile gravitational shearing commonly occurs within these weaker layers accompanied by brittle fracture in the surrounding layers to investigate these mechanisms we have performed high precision direct shear tests using a novel back pressured shearbox on artificial rock samples both with and without graphite layers placed between pre cut shear surfaces the tests used normal stresses up to 800 kpa equivalent to 32 m depth of burial we found that the coefficients of friction for samples with graphite layers embedded in the artificial rock samples 0 30 representing an angle of internal friction of 16 7 were much lower than those without graphite layers on the pre cut surface 0 85 the shear strength of the artificial rocks with embedded layers of graphite decreased abruptly with increasing areal extent of the graphite layer along the shear surface from which it can be inferred that the continuity of a graphite layer in natural pelitic schist has a considerable effect on shear resistance these results suggest that even comparatively low dip angles of schistosity in pelitic schist could initiate microscopic slip along the graphite rich layers

precedent long term gravitational deformation of large scale landslides in the three gorges reservoir area china abstract large scale landslides are common in the three gorges reservoir region due to steep slopes and complex geological conditions fluctuations of reservoir level etc many phenomena and formation mechanisms related to these landslides are not well understood and need more research in this study large scale landslide evolution and formation mechanisms are thoroughly investigated in terms of precedent long term gravitational deformation pltgd three large scale landslides in the three gorges reservoir region huangtupo landslide htpl huanglashi landslide hlsl and baotaping landslide btpl are taken for example to discuss their phenomena and features of pltgd and to investigate the correlation between the pltgds and landslide many features associated with landslides are caused by slow downslope gravitational processes before landslide failure and three criteria for recognition of the pltgd features are summarized the investigation results reveal that the pltgds play an important role in landslide evolution and formation mechanism overall this paper presents evidences for pltgds of large scale landslides and their correlation with landslide evolution which is helpful to understand the formation mechanism of large scale landslides in the three gorges reservoir region

deep seated gravitational slope deformations along the active bocono fault in the central portion of the merida andes western venezuela abstract two very large deep seated gravitational slope deformations in the highlands of the merida andes venezuela are herein described the mucubaji pass and cerro la camacha these slope movements have slid in post last glacial maximum times in addition both landslides are in very close association with the active bocono fault trace the cerro la camacha camacha range landslide is fault bounded along its northwest flank whereas the mucubaji pass mass movement is even cut by the active fault trace the almost 10 km long mucubaji slide mobilizes lgm moraine deposits along the unconformable basement contact la camacha slope movement is a sackung type landslide involving two huge masses that affect the entire northwestern slope of the la camacha range this sackung is at least 20 km long paralleling the active bocono fault trace combination of high relief energy gravitational forces and seismic shaking related to an on site active fault could be responsible for the destabilization of the slopes or massif in both cases although the seismically induced re activation of the la camacha landslide is very likely there is no proof for that yet conversely the mucubaji slide shows geomorphic geodetic and sedimentary evidence of episodic activity in recent times which could be ascribed to seismic triggering in the particular case of the la camacha sackung the combination of dextral slip along the bocono fault and a se dipping fault plane could additionally favor the destabilization of the nw slope of the la camacha range

a sagging along the eastern chianti mts italy abstract a deep seated gravitational slope deformation dgsd affects the eastern side of the chianti mts ridge it develops in an n s to nw se direction and is 10 km wide and 3 4 km long this area corresponds to the eastern side of a main antiform characterised by east verging folds and thrusts involving bedrock of the mesozoic paleogene tuscan units particularly sandstones containing interlayered highly fractured and deformed ligurian rocks shales and limestones with olistostromes the foot of the slope is characterised by tilted plio pleistocene deposits unconformably sealing the bedrock structures as folds thrusts and faults the most significant morphological features are a main escarpment trenches several secondary and counter slope escarpments that together indicate large scale gravitational phenomena the main escarpment is responsible for the headward retreat of the slope and is deeply segmented by numerous arcuate niches that reveal differential movements of single blocks the dgsd is also dissected by sw ne trending streams that often deepen inside the n s trenches minor landslides due to local instability are also present at the foot of the slope the older continental pliocene deposits of the upper valdarno basin crop out although tilted by tectonic movements the deposits have not been severely affected by gravitational deformations this indicates that the movement is a typical sagging a large landslide at an embryonic stage affecting the upper part of the slope but not reaching the valley bottom the deformations are absorbed in the rock mass which is also partially drained by stream incision that prevents high pore pressure the occurrence of down slope and down movement facing escarpments and up slope and up movement facing counter slope escarpments indicate a sagging characterised by a listric spoon shaped geometry the dgsd has a style similar to crustal extensional tectonics such as morton and black s crustal attenuation model although few chronological indications of movements are present the fact that late pleistocene debris deposits widespread in the northern and central apennines are not found at the contact between the escarpment and the trenches suggests a post glacial activity for at least part of the movements recognizing embryonic stage collapse is of primary importance in assessing geological hazard and risk because rapid evolution and collapse could follow

tectonic conditioning revealed by seismic refraction facilitates deep seated landslides in the western escarpment of the main ethiopian rift abstract landslide is a geo hazard phenomenon that has been taking lives and causing severe property damages all over the world mostly in mountainous areas the main ethiopian rift has a unique tectonic setting with complex geological and geomorphological features coupled with continuously deteriorating environmental conditions which made its escarpments vulnerable for landslides the study area is located near the debre sina town within the yizaba wein locality which has been severely affected by frequent landslide problems this work was carried out using a multidisciplinary approach based on geological geomorphological kinematic analysis and geophysical survey seismic refraction investigations were carried out along the yizaba wein landslide main scarp to determine the depth to the bedrock and to the failure plane to assess the stability of the slope to locate possible structural features and to identify the extent of recent landslide activity and to study the subsurface situation the seismic measurements were made along three nearly orthogonal survey lines in the recently affected area a high resolution 2d p wave survey was conducted using a 24 channel seismic unit the seismic refraction results revealed four layers of geomaterials with distinct physical characteristics that contained a subsurface landslide anomaly within the layers the layers were interpreted according to the major lithological units from top to bottom i clay loosely cemented colluvial sediments and highly weathered agglomeratic basalt ii highly to moderately fractured porphyritic basalt ignimbrite volcanic ash and rhyolite trachyte iii moderately to slightly fractured ignimbrite rhyolite trachyte and basalt and iv very strong massive fresh rock bedrock faults and weak zones have also been identified in the bedrock based on the abundance of fractures and subsidiary faults resulting from damage of rocks and change of lithology due to variable fault rock formation strongly influencing the wavefield distribution which usually causes a local decrease of the velocity value the main findings show that the landslide in the yizaba wein locality was caused by its complex geological structural setting and downslope movement of the underlying pyroclastic sediment facilitated by heavy rainfall considering the similar geological and tectonic settings similar mechanisms can be assumed for other landslides along the rift margins and associated highlands of ethiopia

kinematics and geological constraints of the slow moving pisciotta rock slide southern italy abstract the pisciotta landslide is a slow moving deep seated rock slide in the campania region of southern italy which has damaged a provincial road several times in the last decades and currently poses a hazard to the national railway that intersects the toe of the landslide the landslide involves an oligocene turbidite series which is composed of intercalated calcarenites marls and mudrocks the principal objectives of this study were to investigate the morphological evolution of the unstable slope quantitatively analyse ground deformations and construct an engineering geological model that is consistent with the spatial features of the landslide the long term evolution of the unstable slope was assessed through the examination of available aerial photos from 1943 to 2006 kinematic analyses of the ground deformations were conducted based on observed progressive displacement of the road as evident from the topographic maps and orthophotos 1955 2006 and the bi weekly displacement survey of 50 targets distributed across the landslide area september 2006 march 2009 the engineering geological model of the landslide was reconstructed from the stratigraphic data obtained from the study of borehole data and monitoring of inclinometers as well as from geological structural and geophysical surveys the analysis of the aerial photographs revealed an early stage of deformation in 1943 which has been gradually widening since then in addition to the main scarp and the landslide flanks other significant landslide structures such as the longitudinal and transverse cracks as well as the positive or negative morphologies were monitored and mapped in the subsequent years these studies indicated a progressive erosion of the upper part of the slope and a bulging of the foot long term kinematic analysis based on the progressive displacements of the road allowed the measurement of the ground deformations from 1955 to 2009 which revealed a cumulative horizontal displacement of up to 53 m and an average velocity of 0 98 m year 1 which has increased in the recent decades in addition the recent monitoring of the ground deformations demonstrated a continuous activity with an approximately constant rate of displacement and a composite kinematic history of the landslide body through differential displacements and associated velocities the engineering geological model of the landslide was found to be controlled by specific stratigraphic and structural constraints the landslide involves a stratigraphic interval of the saraceno formation nord calabrese tectonic unit with a largely marly argillaceous composition whose structural setting displays complex folding at the mesoscale and faulting with an approximately monocline attitude of bedding and a downslope dip direction at the macroscale the left flank of the landslide rests on a normal fault

temporal behavior of deep seated gravitational slope deformations a review abstract deep seated gravitational slope deformations dsgsds are slow moving hillslope scale mass movements featuring characteristic landforms such as double crested ridges and upslope facing scarps that occur in diverse landscapes throughout the world although these deformations have been studied since the 1960s significant insights to the rates of dsgsds have only been gained within the last two decades owing to progress in geochronology remote sensing and instrumental monitoring absolute age and monitoring data indicate that dsgsd movements are observable over long term 102 years and short term future research directions include constraining the lifespan of dsgsds with absolute age dating and precise high resolution monitoring of spatio temporal displacement across dsgsd bodies it is of great importance to include absolute time scales in the numerical models of dsgsds furthermore combining remote sensing techniques such as synthetic aperture radar interferometry with high resolution lidar scanning and near surface geophysics offers a promising toolkit for collecting very detailed and accurate data on the short term deformation rates of dsgsds

use of permanent scatterers technique for large scale mass movement investigation abstract in the oltrepo pavese northern italy several areas subjected to risk assessment according to italian law are located around a highly fractured sandstone slabs m vallassa sandstone lying on a deformable clayey substratum epiligurian sequence the structural and geomorphologic surveys and comparison with results obtained by some authors in similar geological contexts indicate the possible presence of deep seated gravitational deformations which could be classified as lateral spread the potentiality of the permanent scatterers technique has been explored by the authors for investigating large slope displacements in the oltrepo pavese the permanent scatterers analysis was combined with in situ conventional geomorphological structural and geotechnical studies test sites corresponding to sandstone slabs and areas classified at high risk from the institutional authorities were selected a geological model of each test area was obtained from the integration of the geological geomorphological character of the site with the geotechnical data boreholes piezometers and laboratory tests the ps technique allows to detect and delimit the unstable area and to identify some zones within the mass movement characterized by different displacements rates and thus different degree of hazard

active folding in the algerian earthquake of 10 october 1980 a fold controlling the form of the local topography near el asnam algeria increased in amplitude at the time of the earthquake of 10 october 1980 the deformation occurred rapidly in an elastic brittle manner and not in the gradual ductile fashion in which folds are normally thought to develop

the relationship between geology and landforms along a coastal mountain front northern calabria italy the geomorphology of the central coastal range a north south trending horst along the west coast of northern calabria is governed largely by major faults fault scarps and the distribution of principal rock types as well as by a variety of slope processes operative in a mediterranean climate segments of the major rivers and streams have three principal orientations parallel to major faults in the study area northwest right oblique slip faults oldest e w oblique slip faults ne left oblique slip faults and north south right oblique normal faults youngest all of which cut pre tertiary metamorphic rocks mesozoic limestone miocene molasse and calcarenite small underfit alluvial fans composed chiefly of locally derived debris flow detritus are present at the mouths of large west flowing canyons some of which reach eastward to the crest of the mountain range not only do the north south normal faults displace rocks and structures of all orientations but they also make steep scarps in the small alluvial fans and in sediments of the coastal plain locally some of the scarps are buried by recent debris flow deposits incipient young rivers utilized the weaknesses along the major faults and cracks as avenues of erosion smaller streams and gullies generally flowed westward downflank of the north trending horst and incised thereby deep v shaped canyons some of them have captured older sw flowing canyons locally they were guided in other directions where they encountered faults or tectonic fractures the rocks present a varied resistance to erosion depending upon the degree of cementation by groundwater salts upon the orientation of the foliation and upon the rocks themselves thus mica schist with a relatively flat foliation forms nearly vertical sea cliffs but the sea cliffs are more gentle where the foliation is steep or dips towards the sea therefore downslope movements are facilitated by seaward slip on foliation schistosity bedding and fault surfaces and are evinced especially by large and deep pre holocene landslides sackung in phyllite having areal dimensions up to 2 km2 other downslope processes include surficial creep and soil slip particularly of highly fractured phyllite and schist block sliding and rock falls

deep seated gravitational slope deformations in western sicily controlling factors triggering mechanisms and morphoevolutionary models abstract a study of deep seated gravitational slope deformation dsgsd phenomena affecting areas of various geological and geomorphological settings in western sicily is described western sicily is underlain by a thin skinned imbricate wedge of meso cenozoic carbonate and siliciclastic rocks that formed by the stacking of several thrust nappes over the iblean foreland locally the original thrust sheets are folded and cut by high angle faults large areas of western sicily now display high relief energy due to plio pleistocene block faulting and uplifting and the quaternary morphogenetic phases are characterised by incision thereby triggering widespread dsgsds to identify controlling factors and triggering causes and to develop reliable morphoevolutionary models for the dsgsds of western sicily a geomorphological study based on field surveys and aerial photography interpretations was performed previous geomorphological data relating to well known examples of dsgsds were reconsidered leading to remarkable revisions of the interpretative models in certain cases new data were subsequently collected enabling recognition of additional dsgsd phenomena the whole body of data involves a total of 27 dsgsds affecting areas in two specific geological settings 1 areas with flat thrust surfaces where differential settlements back tilting lateral spreads in competent rocks overlying marls and clays large topples and or block type slope movements may develop and 2 areas where deep rooted carbonate units come into lateral contact with clayey marly units along high angle faults where lateral spreads in brittle homogeneous rocks sinking and or rock flows may occur these dsgsd phenomena are associated with different evolutionary stages allowing a morphoevolutionary model to be defined for the two geological conditions for these two different morphoevolutionary models the following structural features play an important role in the development of dsgsds 1 where carbonate bodies overlie clayey marly rocks triggering of the dsgsds traces back to deformation of a ductile substratum that follows the exhumation of the flat thrust planes and the underlying clayey marly rocks due to block faulting and or stream incision and 2 where homogeneous carbonate rocks hundreds of metres thick crop out the dsgsds are triggered by very high relief energy and tensile stress that follow the combined actions of quaternary block faulting and stream deepening associated with differential erosion

geomorphological features and 3d modelling of montelparo mass movement central italy abstract the ancient village of montelparo marche region central italy is affected by a large translational mass movement the relief is modeled on arenaceous and arenaceous pelitic units overlying pelitic arenaceous terrains the bedding strata form a gently dipping monocline the translational slide is about 1100 m long and 500 700 m wide the upper boundary between the stable area and the sliding mass is marked by a large active trench near the hilltop the main sliding surface is located at a depth ranging between 65 and 100 m in the politic arenaceous unit we studied the mechanism of the slope instability along the stratigraphic contact between a rigid arenaceous unit and an underlying ductile pelitic unit the uncovering of the contact caused by the intense downcutting processes of the river at the hill foot during the holocene favoured the onset of the movement this was enhanced by the fractured bedrock and especially by the jointing we created a numerical model based on the finite differences code flac 3d by using a specific approach for mesh generation the model suggests a further enlargement and deepening of the trench and a sliding direction not aligned with the slope dip direction failure in the model concentrates at and around the main trench all the other elements staying in an elastic state and inducing a rigid sliding the model shows that both the failure onset and the current evolutionary state can be explained by the geological and static conditions of the slope

evolution stages of large deep seated landslides at the front of a subalpine meridional chain maritime alps france abstract studying long term evolution of gravitational slope evolution is a key to understanding deep seated landslide processes this paper deals with three large deep seated landslides dsls at a front of a subalpine meridional chain on the la marbriere slope near the town of grasse alpes maritimes france the geological framework controlling the stability and morphology of the dsls is associated with thick and tamped triassic layers of mudstone with gypsum overlain by highly faulted jurassic limestone gravitational deformation affects the entire slope involving a movement of about 1 1 10 8 m 3 of rock material it creates large disturbances in landscape morphology such as scarps counter slope scarps trenches and other typical gravitational morpho structures geomorphological mapping coupled with deep electrical resistivity tomography ert reveals a strong correlation between these morpho structures and inherited brittle tectonic features this observation relies on spatial and geometrical relations on the surface and at the depth of more than 150 m checked by ert between the most persistent fault and the gravitational morpho structures the specific distribution of the morpho structures on the basis of their morphological typologies and variations in the stage of evolution of three dsls provides an interpretation of their kinematics during the last 400 ka it appears that soft substratums combined with inherited persistent anisotropies are key factors in the development of the dsls indeed outflow of mudstone due to the lithostatic pressure imposed by individual limestone compartments has led to general slope subsidence then a progressive toppling of a rock mass may have led to the catastrophic rock collapse along bedding planes the evolution of the dsls can be divided into three distinct stages represented by three zones a young collapse stage zone 1 a pre collapse stage zone 2 and an old mature stage 400 ka zone 3 as the dsls occur on the same slope and in the same geological context this area offers interesting perspectives for understanding factors controlling the long term gravitational evolution of slopes

distribution probability of large scale landslides in central nepal abstract large scale landslides in the himalaya are defined as huge deep seated landslide masses that occurred in the geological past they are widely distributed in the nepal himalaya the steep topography and high local relief provide high potential for such failures whereas the dynamic geology and adverse climatic conditions play a key role in the occurrence and reactivation of such landslides the major geoscientific problems related with such large scale landslides are 1 difficulties in their identification and delineation 2 sources of small scale failures and 3 reactivation only a few scientific publications have been published concerning large scale landslides in nepal in this context the identification and quantification of large scale landslides and their potential distribution are crucial therefore this study explores the distribution of large scale landslides in the lesser himalaya it provides simple guidelines to identify large scale landslides based on their typical characteristics and using a 3d schematic diagram based on the spatial distribution of landslides geomorphological geological parameters and logistic regression an equation of large scale landslide distribution is also derived the equation is validated by applying it to another area for the new area the area under the receiver operating curve of the landslide distribution probability in the new area is 0 699 and a distribution probability value could explain 65 of existing landslides therefore the regression equation can be applied to areas of the lesser himalaya of central nepal with similar geological and geomorphological conditions

an introductory review on gravitational deformation induced structures fabrics and modeling abstract recent studies have pointed out a similarity between tectonics and slope tectonic induced structures numerous studies have demonstrated that structures and fabrics previously interpreted as of purely geodynamical origin are instead the result of large slope deformation and this led in the past to erroneous interpretations nevertheless their limit seems not clearly defined but it is somehow transitional some studies point out continuity between failures developing at surface with upper crust movements in this contribution the main studies which examine the link between rock structures and slope movements are reviewed the aspects regarding model and scale of observation are discussed together with the role of pre existing weaknesses in the rock mass as slope failures can develop through progressive failure structures and their changes in time and space can be recognized furthermore recognition of the origin of these structures can help in avoiding misinterpretations of regional geology this also suggests the importance of integrating different slope movement classifications based on distribution and pattern of deformation and the application of structural geology techniques a structural geology approach in the landslide community is a tool that can greatly support the hazard quantification and related risks because most of the physical parameters which are used for landslide modeling are derived from geotechnical tests or the emerging geophysical approaches

sediment connectivity a framework for understanding sediment transfer at multiple scales a major challenge for geomorphologists is to scale up small magnitude processes to produce landscape form yet existing approaches have been found to be severely limited new ways to scale erosion and transfer of sediment are thus needed this paper evaluates the concept of sediment connectivity as a framework for understanding processes involved in sediment transfer across multiple scales we propose that the concept of sediment connectivity can be used to explain the connected transfer of sediment from a source to a sink in a catchment and movement of sediment between different zones within a catchment over hillslopes between hillslopes and channels and within channels using fluvial systems as an example we explore four scenarios of sediment connectivity which represent end members of behaviour from fully linked to fully unlinked hydrological and sediment connectivity sediment travel distance when combined with an entrainment parameter reflecting the frequency magnitude response of the system maps onto these end members providing a coherent conceptual model for the upscaling of erosion predictions this conceptual model could be readily expanded to other process domains to provide a more comprehensive underpinning of landscape evolution models thus further research on the controls and dynamics of travel distances under different modes of transport is fundamental copyright 2014 john wiley sons ltd

geology geomorphology and dynamics of the 15 february 2010 maierato landslide calabria italy abstract on 15 february 2010 as a result of intense and long lasting rainfalls a large landslide affected a wide area near the town of maierato calabria italy the studies conducted including i aerial photo interpretation ii geological and geomorphological field investigations iii interpretations of lithology and stratigraphy from borehole data and iv observation of videos filmed during the main diastrophic phases of the landslide and of antecedent google street view images allowed researchers to reconstruct the geological and tectonic setting of the slope and the internal structure of the landslide with the estimation of the depth of the sliding surface the triggering mechanisms and its evolution the analysis of the prelandslide event setting demonstrates that this mass movement is the reactivation of a preexisting landslide of alleged seismic origin remaining at an incipient stage the maierato landslide occurred on a gentle slope made of late miocene to plio pleistocene clastic and evaporitic sedimentary rocks the main basal failure surface that developed on the hemipelagic marls has a maximum depth of 50 m the volume of the landslide is 5 million cubic meters the type of landslide movement is a complex one consisting of a very rapid slide of rock and earth and of flow of debris and earth the landslide clearly shows three major types of failure mechanisms the first type is described as a rapidly moving rotational slide where back tilted blocks of sediment are preserved the second type includes a very rapidly moving translational slide of large rock blocks the third type includes sudden extremely rapid flow slides where the slide material is disaggregated while flowing downward along a gentle slope the slide is a compound one with a retrogressive evolution and transformation into earth and debris flow during the failure after the triggering of the landslide and as a result of the relevant displacement an important portion of the lower evaporitic unit calcare di base formation close to the failure surface collapsed thereby undergoing a quick change of its mechanical behavior that became similar to that of a viscous fluid during the landslide evolution large rocky blocks consisting of miocene evaporitic limestones pliocene silty clays and sands were rafted without severe disturbance on the destructurated and fluidized limestone the intense destructuration and the presence of water transformed the limestone in the lower parts of the unit into a viscous material that was squeezed out of the landslide mass through the jags between the several rafted rocky blocks and along the natural levees of flow tongue this event is a rather frequent combination of mass movements made complicated and spectacular by the fluidization of the weak limestone that imparted great dynamics to the movements such fluidization is an infrequent phenomenon especially in this geological context

how multiple foliations may control large gravitational phenomena a case study from the cismon valley eastern alps italy abstract the right slope of the high cismon valley trento province italy carved into the poly deformed phyllites of the south alpine basement shows evidence of differential quaternary slope evolution which highly depends on how the slope intersects the inherited structures in the study area the regional schistosity outlines a kilometer scale nnw sse trending fold with close flanks and an axial plane dipping to the ne the structure obliquely intersects the nne ssw trending slope so that the northern part of the slope follows the upper limb of the fold and the southern sector coincides with the lower limb and the hinge the secondary axial plane foliation is typically incipient at the fold flanks and much more pervasive and fan shaped near the hinge zone this foliation as well as the asymmetric polyharmonic secondary folds has significant consequences on rock mass mechanical properties and on mechanisms and timing of the gravitational phenomena developed along the slope in particular the joint compressive strength jcs and the geological strength index gsi obtained on stable outcrops outside the deforming area display a decrease from north to south this points to a progressive deterioration of the rock mass strength which directly reflects the influence of the pre existing fabric the results obtained by the analysis of lidar derived digital elevation model show evidence of two different gravitational movements located in the northern and southern sectors of the slope respectively the northern side is characterized by an ongoing deep seated gravitational slope deformation dsgsd likely triggered by post glacial unloading derived from the retreat of the ice tongue that filled the cismon valley during the last glacial maximum lgm conversely the southern part of the slope is the expression of a fully evolved pre lgm gravitational collapse this heterogeneous behavior of the slope is most likely controlled by the secondary foliation and asymmetric polyharmonic folds the former being of paramount importance for the release of the mobilized mass at the crown area and the latter easing or impeding the downslope movement although it is widely accepted that the regional foliation is the dominant controlling factor of dsgsds on poly deformed and highly foliated metamorphic basement our work suggests that the secondary foliation as well as parasitic folds may also have remarkable effects on slope evolution if favorably oriented and sufficiently pervasive

monitoring rapid head scarp movement in an alpine rockslide abstract the aresawa rockslide in the japanese alps which partially collapsed in may 2004 produced a number of new tension cracks in the head area this paper discusses the dynamics of the rock slope and controls on the surface velocity based on the results of on site monitoring of the surface movement and meteorological parameters air and ground surface temperatures precipitation and snow depth the rock mass deformation progressed at ca 60 cm yr 1 mainly along a slip plane dipping downslope at ca 50 the surface velocity of the slipping rock mass showed a significant seasonal variation in response to the water infiltration the velocity was small 1 mm day 1 in winter subzero air temperatures and a heat insulating snow cover and resulting growth of seasonal frost prevent water infiltration into the bedrock and contribute to the rock slope stability most of the movement in this period is attributed to gravitational deformation originating from the overburden pressure in contrast the surface velocity increased up to 10 mm day 1 during snow melting and snow free periods snowmelt and rainfalls promote water infiltration into the bedrock destabilizing the rock slope and accelerating the rock slip such a rapid movement is attributed to water induced sliding superimposed on gravitational deformation

mountain slope deformations along thrust fronts in jointed limestone an equivalent continuum modelling approach abstract engineering geology studies of natural slope stability have rarely relied on continuum modelling of discontinuous rock mass or the use of conventional constitutive laws in fem or fdm codes the paper proposes the use of numerical modelling based on a practical equivalent continuum approach for analysing the deep seated gravitational slope deformations dsgsd observed in the thrust front area of the lepini mountains italian apennines the dsgsd phenomena affect a carbonate ridge close to the villages of san sebastiano and sgurgola inducing a significant risk this study began with the construction of engineering geology sections by distinguishing lithotechnical units on the basis of both site and geomechanical parameters considering geological and geomorphological field evidence the numerical simulations validated the assumed kinematic model of the slope these simulations aimed at estimating the instability of the affected rock masses by identifying a critical mass beyond which ongoing deformations become morphologically evident on the involved slope a ratio of the weight of a critical mass which is the minimum mass required to produce some geomorphological evidence to the weight of the mass involved in the gravitational slope deformations was calculated in order to quantitatively assess the evolutionary stage of the ongoing deformations the calculated ratio demonstrates a more advanced evolutionary stage for the slope sector near the village of sgurgola due to its particular geological setting than the one near the village of san sebastiano

mass movement geologic structure and morphologic evolution of the pizzotto greci slope calabria italy abstract deep seated mass movements of different types affect the pizzotto greci slope in northwest calabria italy the slope is carved out of phyllitic rocks capped by gneissic layers its geological structure is extremely complicated by tectonic structures that pervasively cross the slope transversely and downslope a large scale gravitational deformation of sackung type affects the slope on the upslope side a debris flow source area feeds a large fan constructed by recurrent debris flow deposits aggradation is consequently occurring along the stream at the base of the slope in order to define the internal structure of the slope for a stability slope model geological geostructural geomorphological historical and dendrogeomorphologic studies as well as direct geotechnical logs and indirect geophysical investigations have been carried out over a two year project financed by the ec environment programme the main aspects of the geological and geomorphological studies and some preliminary geotechnical data are presented here along with a conceptual model aimed at describing the relationships between the mass movements on the slope and the construction destruction stages of the fan at the base of the slope the model is based on the assumption that aggradation has a stabilising effect on the slope thus debris flow activity is reduced and consequently destruction of the fan occurs bringing the slope again towards unstable conditions the reactivation of mass movement however leads to the reconstruction of the fan and the buttressing effect at the base of the slope is restored thus the process is cyclic and self regulating

discrete element simulations of gravitational volcanic deformation 1 deformation structures and geometries 1 we have carried out two dimensional particle dynamics simulations of granular piles subject to frictional coulomb failure criteria to gain a first order understanding of different modes of gravitational deformation within volcanoes under uniform basal and internal strength conditions granular piles grow self similarly developing distinctive stratigraphies morphologies and structures piles constructed upon cohesive substrates exhibit particle avalanching forming outward dipping strata and angle of repose slopes systematic decreases in basal strength lead to progressively deeper and steeper internal detachment faults and slip along a basal decollement landslide forms grade from shallow slumps to deep seated landslide and finally to axial subsidence and outward flank displacements or volcanic spreading surface slopes decrease and develop concave up morphologies with decreasing decollement strength depositional layers tilt progressively inward spatial variations in basal strength cause lateral transitions in pile structure stratigraphy and morphology this approximation of volcanoes as coulomb granular piles reproduces the richness of deformational structures and surface morphologies in many volcanic settings the gentle slopes of hawaiian volcanoes and olympus mons on mars suggest weak basal decollements that enable volcanic spreading high angle normal faults favored above weak decollements are interpreted in both settings and may explain catastrophic sector collapse in hawaii and broad aureole deposits surrounding olympus mons in contrast steeper slopes and shallow detachment faults predominate in the canary islands thought to lack a weak decollement favoring smaller more frequent slope failures than predicted for hawaii the numerical results provide a useful predictive tool for interpreting dynamic behavior and associated geologic hazards of active volcanoes