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

paraglacial rock slope stability glaciation and deglaciation along with their associated climatic and non climatic processes modify slope stresses and influence slope stability paraglacial slope failures are those that are a part of or influenced by the transition from glacial conditions to non glacial conditions gravitational failure of rock slopes is a primary and dominant process of slope evolution in mountainous terrain and is the subject of this paper which 1 reviews the approaches taken for researching paraglacial rock slope failure patterns and processes 2 summarises the spatial and temporal patterns of post glacial failures 3 assesses the factors influencing slope stability during glaciation and deglaciation 4 explores some of the applications of paraglacial research and 5 highlights some of the outstanding issues to be resolved and provides recommendations for terminology relating to paraglacial slope processes

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

time constraints for the evolution of a large slope collapse in karstified mountainous terrain of the southwestern crimean mountains ukraine abstract deep seated gravitational deformations are significant denudational agents of rock slopes at the margins of karstified plateaus of the crimean mountains ukraine the aim of this article is to study long term evolution of a giant rock slope failure close to the black sea coast in the southwestern tip of the mountains near foros town the failure evolved in highly anisotropic limestones overlying plastic flysch layers where the main headscarp follows a strike slip fault we tested a new chronological strategy based on 14 c and u th series dating of speleothems from unroofed caves exposed in the headscarp area of the slope failure this approach made it possible to state maximum age of the slope collapse in individual parts of the deformed slope obtained results indicate that extension of discontinuities together with their karstification can be traced to 300 ka bp whereas evolution of the main headscarp started 110 ka bp and since then it has propagated in the eastward direction the youngest slope failure in the easternmost part of the studied collapse is of late holocene age our study indicates that conditions for large rock slope failures in carbonate areas can be prepared by speleogenesis or combined effects of propagation of cracks and their solution based expansion furthermore large rock slope failures can be important factors for the genesis of unroofed caves

tectonic controls on a large landslide complex williams fork mountains near dillon colorado abstract an extensive 25 km2 landslide complex covers a large area on the west side of the williams fork mountains in central colorado the complex is deeply weathered and incised and in most places geomorphic evidence of sliding breakaways hummocky topography transverse ridges and lobate distal zones are no longer visible indicating that the main mass of the slide has long been inactive however localized holocene reactivation of the landslide deposits is common above the timberline at about 3300 m and locally at lower elevations clasts within the complex as long as several tens of meters are entirely of crystalline basement proterozoic gneiss and granitic rocks from the hanging wall of the laramide late cretaceous to early tertiary west directed williams range thrust which forms the western structural boundary of the colorado front range late cretaceous shale and sandstone compose most footwall rocks the crystalline hanging wall rocks are pervasively fractured or shattered and alteration to clay minerals is locally well developed sackung structures trenches or small scale grabens and upslope facing scarps are common near the rounded crest of the range suggesting gravitational spreading of the fractured rocks and oversteepening of the mountain flanks late tertiary and quaternary incision of the blue river valley just west of the williams fork mountains contributed to the oversteepening major landslide movement is suspected during periods of deglaciation when abundant meltwater increased pore water pressure in bedrock fractures a fault flexure model for the development of the widespread fracturing and weakening of the proterozoic basement proposes that the surface of the williams range thrust contains a concave downward flexure the axis of which coincides approximately with the contact in the footwall between proterozoic basement and mostly cretaceous rocks movement of brittle hanging wall rocks through the flexure during laramide deformation pervasively fractured the hanging wall rocks

a giant deep seated slope deformation in the italian alps studied by paleoseismological and morphometric techniques this work proves the existence of a large deep seated gravitational slope deformation dgsd in a hilly region of the southwestern alps whereas dgsd are usually linked with high relief energy in mountain environments moreover we describe the usefulness of applying paleoseismological techniques by means of trench excavation to date and understand the deformation history and genesis of recent morphostructures and we found evidence of causative relationships between dgsd and surface landslides the studied dgsd of mt croce della tola mt scincina italy is the largest of the western alps it is 7 km long and involves a minimum area of 16 km2 with a volume 3 5 km3 probably extending further ne beneath lake maggiore surface several parallel scarps representing the surface expression of slip planes affect the upper part of the slope whereas the lower part presents a convex profile dgsd at mt croce della tola started in the last interglacial period 120 40 ka bp and the following glacial phase was not able to significantly modify the general slope geometry post glacial deformation also occurred especially at mt scincina after 25 ka bp post glacial and active surface landslides developed on the convex lower part of the slope suggesting that they resulted from instability due to the new profile assumed by the slopes during the deep seated deformation the occurrence of mt scincina dgsd with a very low topographic gradient is interpreted as an effect induced by on other large dgsd

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

comments on structural tectonic controls and geomorphology of the karst corridors in alpine limestone ridges southern carpathians romania by l tirlă and i vijulie geomorphology 197 2013 123 136 abstract in the recently published paper by tirl and vijulie 2013 the authors interpret the abundant trenches affecting the limestone ridge of the v nturari a buila massif southern carpathians romania as bogaz like landforms syn kluftkarren karst corridors karst streets zanjones etc these karst features originated according to the authors through the corrosion of structurally anisotropic limestone bedrock this proposed origin is supported by a comparison of the rose diagrams of the directions of both bogaz and tectonic discontinuities by a morphometric analysis and by observations of the speleothem remnants covering the exposed fault surfaces furthermore the authors described the typically karstic settings of the area such as extremely poor surface drainage subterranean connections between the karst corridors and karst springs in pocket valleys we disagree with their main interpretations and argue that the presumed bogaz are gravitationally induced grabens and trenches created by mass movement activity namely by deep seated slope failures the speleothem remnants are interpreted as flowstones deposited during the subsurface widening of the joints by gravitational activity these speleothem remnants became fossil and even rotated from the original position after sufficient widening of the joints and subsequent exposure of the crevices to the surface due to slope failure progression the morphology of the slope failure along the v nturari a buila massif is similar to numerous other elevated ridges within the carpathian mountains

do the billecocha normal faults ecuador reveal extension due to lithospheric body forces in the northern andes active compressional and transcurrent structures are widely reported for the entire northern andes whereas there is no clear evidence of extensional tectonics in that region in contrast both active compressional and extensional structures occur extensively in the central andes extensional tectonism in the central andes occurs mainly in high plateaus of large wavelength 100 km and is interpreted to have resulted from the effect of compensated high topography at the lithospheric scale the observation of holocene normal faults on the low wavelength 15 km billecocha high plateau in the northern ecuadorian andes raises a problem could the lithospheric body forces be the cause of the normal faulting in a chain with a mean altitude of 2800 m compared to the central andes where normal faulting is widely distributed across the chain normal faulting on the billecocha plateau is concentrated in a restricted 4 km wide zone in addition normal faulting does not extend further than a few kilometres eastward where compressive structures have been observed considering the local character of the extension body forces at the lithospheric scale cannot be responsible for this normal faulting and thus we can preclude a significant lowering of the magnitude of hmax in the northern andes with respect to the central andes analysis of these normal faults shows that normal faulting occurred between 10 000 yr and 6000 yr b p in addition the relationship between the geometrical parameters vertical throw and rupture length of the major normal fault differs significantly from that given empirically by methods based on scale laws in such a case the billecocha normal faults are unlikely to have a tectonic origin various local processes e g gravity gliding sackung that may be possible are contemplated for triggering the normal faulting in addition a theoretical simple 2 d model is proposed in where local conditions peculiar to the plateau structure glaciation and the surrounding areas are taken into account in this model normal faulting occurs by shearing along the planes of weakness bedding planes in response to the elastic rebound of the fluid saturated plateau which prevailed after the last glaciation

characterization of exogenic fulgurites from an archaeological site in tiedra valladolid spainp martin ramos et al exogenic fulgurites from tiedra valladolid spain studies on type v fulgurites are very sparse in the literature this work reports on the characterization of natural exogenic fulgurites found at the archaeological site of cerro de la ermita tiedra valladolid spain which was firstly a celtiberian and then a roman locum sacrum data from x ray powder diffraction x ray fluorescence spectroscopy fourier transform infrared spectroscopy and raman spectroscopy suggest that the fulgurites consist of naquite piroxenes iron oxides shocked quartz and neo formed cristobalite

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

impact of weathering on the geomechanical properties of rocks along thermal metamorphic contact belts and morpho evolutionary processes the deep seated gravitational slope deformations of mt granieri salincriti calabria italy abstract numerous deep seated gravitational slope deformations dsgsds occur throughout italy that originate from particular tectono stratigraphic settings relief seismicity deglaciation as well as from intense and deep processes of chemico physical weathering of crystalline metamorphic rocks these dsgsds are particularly widespread in the calabrian mountains this study is focused on the mt granieri salincriti slope on the ionian side of the serre massif where granites and granodiorites stilo unit palaeozoic are in contact with metamorphites through a thermal metamorphic aureole this setting generates deep geochemical processes inducing intense chemical weathering these processes are mainly due to the interaction between groundwater and the sulphides that are contained in the local pegmatitic hydrothermal intrusions especially along the thermal metamorphic contact belt the mt granieri salincriti slope has an important dsgsd which is associated with many active and or quiescent landslides among these landslides the salincriti rock avalanche debris flow about 2 m m3 represents the paroxysmal and terminal stage of the deep creep deformations of mt granieri typifying a geological setting that is common in the calabrian arc this multi disciplinary study assessed the weathering susceptibility of the local crystalline metamorphic rocks especially those lying along thermal metamorphic contact belts by characterising the weathering horizons and the spatial distribution of weathering in the rock mass the study was also aimed at identifying the relations between weathering above all deep geochemical processes effects on rocks and slope morphodynamics the methodology was based on detailed geological data geological engineering surveys geomorphology and surface hydrogeology analyses as well as physico mechanical laboratory tests these investigations supported by a monitoring program led to the development of an engineering geological model of the slope geological character attributed to a thermal metamorphic contact belt geomorphological evidence and geomechanical elements elucidated the interactions between deep geochemical processes and weak belts in the investigated rocks as well as the critical role that these interactions play in the evolution of deep seated creep deformations and associated shallow landslides

uphill facing antislope scarps in the coast mountains southwest british columbia uphill facing scarps are examined at affliction creek a glacierized area within the meager creek volcanic complex of southwest british columbia scarps occur directly downslope of tension cracks and are considered to have developed from a combination of 1 antithetic movement between partly toppled slices of rock defined by a master joint set dipping into the slope and 2 erosion of the upslope face of each tension crack leaving the downslope face prominent as an antislope scarp a kinematic test for toppling failure is described glacial erosion and rapid glacial downwasting are probable causes of toppling lichenometric data indicate significant scarp development since affliction glacier attained its maximum neoglacial dimensions about 140 yr ago dilatancy is cited as a possible mechanism for scarp stabilization

late holocene episodic displacement on fault scarps related to interstratal dissolution of evaporites teruel neogene graben ne spain abstract the mio pliocene formations of the turolian type section teruel graben spain have sagged due to dissolution of the underlying triassic evaporites generating a 1 7 km long monocline and accompanying synform with 130 m of structural relief the crest of the monocline is affected by a graben that counterbalances the shortening caused by passive bending in the adjacent syncline this graben is controlled by a master synthetic fault and a swarm of antithetic and synthetic faults with a conspicuous geomorphic expression after acquiring ground penetrating radar gpr profiles three trenches were excavated in depressions associated with uphill facing fault scarps to our knowledge these are the first trenches excavated across faults caused by deep seated dissolution of evaporites the geometrical relationships observed in two trenches indicate late holocene episodic displacement as many as 3 events some of the parameters estimated for the investigated faults are clearly different from those expectable for tectonic faults in this intraplate area they include high apparent vertical slip rates 0 6 1 mm yr low average recurrence of faulting events 1 2 2 ka and very high displacement per event values 65 cm for surface ruptures less then 200 m long our findings suggest that considering evaporite collapse faults as creeping structures is not a reliable criterion to differentiate between tectonic faults seismogenic and dissolution induced gravitational faults nonseismogenic

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

deformation of high slopes in different rocks after wurmian deglaciation in the gailtal austria abstract in the southern part of the eastern alps extended mass movements in different rocks are described in a sequence of crystalline rocks mainly mica schists and phyllonite and sediments sandstone siltstone and limestones various types of mass movements due to mechanical properties of the rocks occurred therefore a great scale bending along with rotational gliding and toppling of the bigger blocks can be recognized in the mica schists in the major parts of the slopes this slope failure leads to a complete disintegration of structures in the phyllonites in the sedimentary part of the sequence the brittle limestone as the competent part failed above the soft incompetent base the main reason for this mostly active deformation of the slopes is glacial erosion causing overdeepened valleys and steep slopes especially active parts are caused by strong river erosion all these phenomena are temporarily closely related to the development of the glaciers

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

quaternary deformations along the engadine gruf tectonic system swiss italian alps the engadine line el is a seismically active fault in southeastern switzerland in the field we studied its western segment presently not affected by seismicity but characterised by features suggesting neotectonic motions and the coterminous gruf line uphill and downhill facing scarps offset rivers non equilibrium hydrological conditions and aligned deep seated gravitational slope deformations are dominant in the western sector of the el in the inn valley landform offsets and the most recent fault striations point to oblique left lateral strike slip close to the el at the maloja pass a huge collapse beheaded the inn valley trench excavation with palaeoseismic analysis stratigraphic correlations of quaternary deposits and optically stimulated luminescence dating indicate that the collapse and faulting mostly occurred in the late pleistocene in the bregaglia valley the gruf line stretches along the southwestern extension of the el six deep seated gravitational slope deformations developed along the gruf line and were dated to pre and post last glacial maximum times we suggest that the western sector of the el moved also in a pleistocene time interval during which tectonic forces in the area were probably larger than at present favouring local uplift widespread gravity deformation and retrogressive slope failure at the inn valley head copyright 2007 john wiley sons ltd

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

gravity tectonics of topographic ridges halokinesis and gravitational spreading in the western ogaden ethiopia the cenozoic history of the western ogaden region of ethiopia between the ethiopian rift and the south afar margin is marked by uplift and incision of the ogaden plateau down to the gorrahei formation an upper cretaceous evaporite formation debuttressing of this and the overlying sedimentary formations resulted in widespread and spectacular gravitational spreading landforms over a minimum surface area of 15 000 km2 most of which remains unstudied after clearing up some misconceptions about the surface geology of the study area the kebenawa ridge in the audo range observations are reported that point to a tectonic style controlled by halokinesis and subsequently gravitational spreading the role of diapirism and karstification in the observed halokinesis is discussed as well as the influence of halokinesis on gravitational spreading spreading is in part akin to sackung in that ridge deformation features include a crestal graben and basal ridge topography extrusion and deformation was triggered by lateral ridge debuttressing ridge spreading also presents analogy with gravitational spreading of the canyonlands grabens in the needles district canyonlands national park utah the scale and the mechanisms are found to be basically similar but two differences are noted first incision by the drainage network in response to plateau uplift in ethiopia has debuttressed the topography along two parallel rivers instead of a single river the colorado river in utah secondly incision proceeded to the base of the evaporite layer in the ogaden whereas incision has not exceeded the top of the evaporite layer in utah these differences may have influenced the details of the spreading mechanisms in ways that remain to be investigated overall in ethiopia association of halokinesis and a transitional mode of gravitational spreading at the interface between narrow ridge spreading sackung and plateau spreading canyonlands type illustrates a fascinating and unusual ridge evolution style

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

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

geomorphology and geochronology of sackung features uphill facing scarps in the central spanish pyrenees abstract the paper analyses uphill facing scarps and associated troughs developed in the oversteepened slopes of two neighbouring glacial valleys in the central spanish pyrenees previous studies of sackung landforms in the pyrenees have argued for deglacial unloading as the genetic mechanism but this causal and temporal relationship has not been proved due to the lack of chronological data the antislope scarps in the two studied locations vallibierna and estos are developed in palaeozoic metasedimentary rocks parallel to the contour lines and the structural grain occur in the intermediate sector of the hillslope and are up to 0 5 km long and several meters high a trench was excavated in a sackung trough fill in each of the valleys in order to gain information about their chronology and genesis charcoal from the lowermost unit in vallibierna provided an age of 5 9 cal ka for the sackung and extrapolation of the three dates obtained in estos indicates that the trough formed ca 7 6 7 8 cal ka deglaciation of the studied sectors of the valleys occurred between 16 and 13 ka the time lag of 5 ka suggests that glacial erosion and the subsequent debutressing of the oversteepened valley walls created slopes predisposed to sackung development but did not initiate the movement seismic shaking is proposed as a probable triggering factor this hypothesis although supported by the sudden deformation event recorded by a failure plane exposed in vallibierna trench and by the seismic and neotectonic activity of the area cannot be proved due to the lack of chronological information about paleoearthquakes

deciphering the effect of climate change on landslide activity a review abstract increased landslide activity is commonly listed as an expected impact of human induced climate change this paper examines the theoretical and empirical bases for this assertion it identifies the mechanisms by which climate can induce landsliding and examines the manner in which these mechanisms may respond to changes in a range of climatic parameters it is argued that inherent limiting stability factors which vary with different terrain conditions and landslide types ultimately govern the nature of response to changing climate several modelling approaches are evaluated on the basis of their potential to predict landslide response to climate projections given reliable input data of appropriate form and resolution the existing slope stability hydrological and statistical models are for the most part capable of yielding useful prognoses on occurrence reactivation magnitude and frequency of landsliding while there is a strong theoretical basis for increased landslide activity as a result of predicted climate change there remains a high level of uncertainty resulting from the margins of error inherent in scenario driven global climate predictions and the lack of sufficient spatial resolution of currently available downscaled projections examples from new zealand are used to illustrate the extent to which changes resulting from human activity have affected slope stability changes resulting from human activity are seen as a factor of equal if not greater importance than climate change in affecting the temporal and spatial occurrence of landslides

cre dating on the head scarp of a major landslide sechilienne french alps age constraints on holocene kinematics cosmic ray exposure cre dating applied to the active sechilienne landslide romanche valley belledonne massif french alps provides information about its holocene dynamics from initiation to present day activity glacier retreat at 1100 m a s l is estimated at 16 6 0 6 10be ka from glacially polished bedrock samples with total deglaciation of the valley achieved at least by 13 3 ka application of the cre method along vertical profiles sampled with a high spatial resolution of 3 m on the head scarp yields 1 an initiation of the rock slope failure at 6 4 1 4 10be ka and 2 a continuous rock slope failure activity with a mean head scarp exposure rate of 0 6 cm yr the data suggest an increase of the head scarp exposure rate between 2 3 and 1 0 ka after this acceleration phase the exposure rate is similar to that obtained by the present day monitoring data over 20 years in the depletion zone 1 3 cm yr since the failure initiation occurred more than 5400 yr after the total deglaciation of the valley the slope failure does not appear as an immediate consequence of debutressing in the romanche valley this result is consistent with studies of other large alpine rockslides in the alps failure initiation of the sechilienne landslide occurred during the holocene climatic optimum a hot and wet period the temperature and precipitation changes of this climatic optimum seem to have a worsening effect at the regional scale to trigger large mass wasting in this glacial alpine valley

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

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

the role of mass movements on landscape evolution in the central karakoram discussion and speculation abstract mass movement constitutes an important process in the evolution of landscapes in mountain regions however the role of massive slope failures in denudational unloading and landscape evolution has not been extensively studied large scale mass movements in one of the greatest mountain ranges on earth the central karakoram in pakistan were therefore examined to help evaluate their role in landscape evolution in high mountains specifically four major mass movement complexes ghoro choh rock avalanche busper sackung and slope failure gomboro slope failure and urdokas rockslide each comprising 10 6 m 3 of debris were assessed and mapped in detail two of these mass movement complexes the ghoro choh rock avalanche and gomboro slope failure were dated using terrestrial cosmogenic nuclides the ages of occurrence of the mass movement complexes studied in the central karakoram date from the late pleistocene to the holocene the four major mass movement complexes all involved the removal of mass from the tops of mountain ridges and peaks that failed and were subsequently transported towards the bottom of their respective valleys such massive movement of mass is anomalous compared to other forms of mass movement and is generally spatially coincident with exposed deeply buried gneiss dome structures these large scale movements appear to be part of a coupled system involving river incision and glacial debuttrussing although earthquakes might have triggered these mass movements this study illustrates the role of climate forcing which is part of a coupled system of denudational unloading but it is unclear whether high magnitude low frequency events such as these initiate the isostatic and tectonic influx of mass or if sustained high magnitude denudation resulting from a coupled system is responsible for the exhumation of buried structures

10be ages reveal 12 ka of gravitational movement in a major sackung of the western alps france abstract the rognier sackung which extends ne sw for more than 9 km is a major gravitational morpho structure located in the western alps we used the 10 be cosmic ray exposure dating method on 23 samples to unravel its history and better understand its genetic mechanism we found that the average slip rate on sackung faults varies from 0 3 to 3 2 mm yr 1 conjugate sackung faults are contemporaneous in agreement with a model in which the whole mountain ridge is involved in the gravitational deformation 600 m thick multiple samples on single faults suggest that the development of this sackung started before 12 ka and that it is still active we cannot exclude the possibility that the dissolution of the underlying triassic evaporites participated in the sagging of mt rognier however the age of this sackung and the presence of the lauziere sackung on the other side of the arcs valley support glacial erosion and debuttressing following the retreat of the valley glacier as the main causes of these large gravitational structures the long and permanent activity of the rognier sackung contrasts with that of the neighbouring arcs sackung which we previously dated using the same method and showed that it is a result of flexural toppling along with the proximity of the rognier sackung to the belledonne border active fault its long history suggests that earthquake shaking contributed to maintain its activity additionally two ages confirm that in the western alps rock glaciers formed mainly during the younger dryas this study allowed the determination of the best sampling strategy for future cre dating of these types of gravitational structures

use of differential sar interferometry in monitoring and modelling large slope instability at maratea basilicata italy abstract differential synthetic aperture radar sar interferometry diffsar allows in principle to measure very small movements of the ground and to cover in continuity large areas so that it can be considered as a potentially ideal tool to investigate landslides and other slope instability in this paper we explore the use of this technique to improve our knowledge of the slope instability of a well investigated area the maratea valley affected by continuous slow movements producing an impressive sackung type phenomenon which poses several unanswered questions in particular by using this technique we analyse the time evolution of ground movements from 1997 to 2000 the slope movements during this same time interval have also been monitored in the past by using other techniques such as electronic distance meter edm and gps measurements gps and diffsar results are here compared in our implementation of the diffsar technique the problem of decorrelation noise is faced by using a phase unwrapping approach that allows to process sparse data and the impact of atmospheric artefacts is reduced by performing a temporal analysis of the deformations observed in successive interferograms in this study we also show that it is possible to perform a temporal analysis of continuous slow landslide movements by using a limited number of ers sar data sets and low precision topographic information all the acquired data edm gps and diffsar are consistent and allow a kinematic model of instability within the investigated time interval to be proposed a map of slopes subject to different velocities of vertical displacements was delineated modifying previous knowledge within the valley progressive and almost linear displacements over time were confirmed

giant non catastrophic landslides and the long term exhumation of the european alps landslides influence local slope morphology affect sediment flux from hillslopes to rivers and mass wasting in response to tectonics and climate forcing however the links between giant non catastrophic landslides known as deep seated gravitational slope deformations dsgsds and the long term evolution of orogenic landscapes are almost unknown we explore these links in the european alps using the first orogen scale inventory of dsgsds 900 over an area 105 km2 and a dataset of published apatite fission track ages 1000 that provides an estimate of the long term exhumation patterns of the orogen we show that dsgsds are more widespread than previously considered and exhibit an orogen scale distribution not explained by well known local lithological and structural controls we test the hypothesis that this orogen scale distribution correlates to the long term evolution of the alps by subdividing the study area into 37 square sub areas 50 50 km classified according to combinations of long term exhumation and mean annual rainfall on each sub area we perform a morphometric analysis of topography hypsometry relief slope excluding local and regional controls due to rock type and structure dsgsds tend to cluster in areas with intermediate exhumation rates fission track age between 10 and 40 ma where large scale topography is less dissected and incision is localised along major valleys here dsgsd abundance correlates positively with the degree of valley incision and related relief instead dsgsds lack in areas which underwent either low exhumation rates resulting in insufficient relief production or high exhumation rates associated to rapid uplift or higher erosional dissection of topography negative correlation between dsgsd abundance and mean annual rainfall suggests that effective hydrological surface processes contribute on the long term timescale to the development of large scale topography unfavourable to dsgsds especially in areas of high exhumation rates where dsgsds are abundant long lasting slope deformations effectively adjust post glacial relief by reducing slope inclination values and are thus expected to significantly contribute to the long term denudation of active orogens

differentiating between gravitational and tectonic faults by means of geomorphological mapping trenching and geophysical surveys the case of the zenzano fault iberian chain n spain abstract the zenzano fault scarp has been developed on the top of a 475 m high erosional escarpment underlain by an upper brittle sequence and a lower halite bearing evaporitic formation the 1850 m long fault with a maximum displacement of 45 m and parallel to the escarpment has offset the back of a dip slope generating an antislope scarp with prominent triangular facets up to 38 m high and obstructing consequent transverse drainages defeated streams both gravitational and tectonic interpretations were previously proposed for this active surface rupture the fault scarp has been investigated by detailed geological and geomorphological mapping geophysical surveys gpr and ert and two trenches excavated across the fault in disrupted drainages the geophysical profiles clearly imaged the fault helping to site the trenches and roughly estimate the thickness of the deposits accumulated in the downthrown block although the maximum displacement to length ratio dmax l of the fault fall within the range of tectonic faults of similar length according to the world database the geological and geomorphological context together with several parameters reveal that this structure corresponds to a gravitational failure 1 anomalously high vertical displacement per event 1 4 m 2 high apparent vertical slip rate 0 6 mm year and 3 short recurrence interval of faulting events the negligible horizontal displacement component on the dip slip fault as well as the presence of very large caprock collapse sinkholes and saline springs strongly suggest that interstratal karstification of the halite bearing evaporites has played a primary role in the development of the gravitational failure the formation of this morphostructure has been favoured by pre existing tectonic faults erosional unloading related to the removal of an overburden ca 800 m thick and enhanced groundwater recharge due to the blockage of the drainage this work illustrates that the proposed multidisciplinary approach allows the identification of features and calculation of parameters that may help to elucidate whether an active failure has a gravitational or a tectonic origin

large rock slope failures in the highlands of scotland characterisation causes and spatial distribution abstract a comprehensive database of larger rock slope failures rsfs has been compiled and characterised for a whole mountain range possibly for the first time apart from iceland most rsfs in the scottish highlands occurred soon after deglaciation a threshold size of 0 25 km 2 focuses on rsfs which contribute significantly to gross erosion in the glacial paraglacial cycle and on the spatial concentration of this poorly recognised process database verification indicates that at least 90 of the total extant population in the highlands is covered standard mass movement typologies are broadly applicable but require some refinement to characterise rsfs in a passive margin glaciated mountain range comprised mainly of ancient metasediments most larger rsfs here are complex and difficult to categorise a continuum from cataclasmic failures including rock avalanches through arrested translational slides to almost in situ slope deformations is identified the prevailing modes of large rsf are arrested short travel translational sliding and gravitational sagging cataclasmic failure is rare and sub cataclasmic outcomes are more evident a significant class of deformations exhibits compressional rather than extensional features and may be responding to localised glacio isostatic rebound stresses the large rsf population is widely but very unevenly distributed across the main mountain areas 65 are in seven main clusters with the rest non randomly scattered previous glaciological lithological and seismotectonic explanations are insufficient to explain this spatial pattern and overlook the basic engineering geology prerequisites for failure massifs of similar relief and lithology can display intense or sparse rsf incidence geomorphological appraisal suggests an association with recently active glacial breaches of main and secondary watersheds with rsf being scarce or absent in valleys inherited from tertiary uplift and in mountain groups away from the main watersheds valleys which adapted early to ice discharge are seen as stress hardened with their slopes unlikely to reach critical thresholds for failure after subsequent reoccupations by ice concentrated erosion in the last glaciations is most likely to be found close to where breaches are actively forming or enlarging such erosion in the slope foot and valley floor may have daylighted failure planes or generated rebound stresses augmenting those from other endemic sources sufficiently to provoke widespread paraglacial rsf slope stress models for deglaciated valleys and comparative studies in other glaciated mountain ranges are required to test this concept and may assist in geohazard assessments

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

are sackungen diagnostic features of de glaciated mountains abstract deep seated gravitational slope deformations dsgsds with characteristic sackung landforms e g double crests trenches uphill facing scarps and toe bulging are considered by some researchers to be diagnostic features indicating past mountain glaciations however an extensive literature review on sackung features throughout the world reveals that in some regions paraglacial processes are not the causes of such phenomena sackungen occur across a diverse spectrum of mountain types with different morphoclimatic histories including regions that have never experienced glaciation to reinforce that sackungen may originate independently of glaciation we also include two case studies from the western carpathians czech republic and slovakia which are supported by detailed geomorphic mapping trenching and absolute dating 10 be 14 c and osl on the ond ejnik ridge outer western carpathians czech republic sackungen occur in the mid holocene in the medium high mountains which are beyond the pleistocene glacial limits on the salatin mt tatra mts slovakia the sackungen which occur in formerly glaciated terrain date between 7 5 and 4 2 ka bp representing a 4 ka time lag after the disappearance of glaciers this suggests that the direct link between the ice retreat and the onset of sackung formation is not obvious even in the case of the once glaciated mountain range although paraglacial stress release is undoubtedly one of the crucial causes of sackung genesis in many mountain regions it is not the only important mechanism therefore despite occurring in numerous de glaciated mountains sackung features cannot be considered as proof of past mountain glaciations e g during analysis of extra terrestrial settings

timing of glacier advances and climate in the high tatra mountains western carpathians during the last glacial maximum during the last glacial maximum lgm long valley glaciers developed on the northern and southern sides of the high tatra mountains poland and slovakia chlorine 36 exposure dating of moraine boulders suggests two major phases of moraine stabilization at 26 21 ka lgm i maximum and at 18 ka lgm ii the dates suggest a significantly earlier maximum advance on the southern side of the range reconstructing the geometry of four glaciers in the sucha woda panszczyca mlynicka and velicka valleys allowed determining their equilibrium line altitudes elas at 1460 1460 1650 and 1700 m asl respectively based on a positive degree day model the mass balance and climatic parameter anomaly temperature and precipitation has been constrained for lgm i advance modeling results indicate slightly different conditions between northern and southern slopes the n s ela gradient finds confirmation in slightly higher temperature at least 1 c or lower precipitation 15 on the south facing glaciers during lgm i the precipitation distribution over the high tatra mountains indicates potentially different lgm atmospheric circulation than at the present day with reduced northwesterly inflow and increased southerly and westerly inflows of moist air masses

deep seated gravitational slope deformations in the european alps abstract deep seated gravitational slope deformations dsgsd are widespread phenomena recognized in different mountain ranges worldwide the distribution of such phenomena at the scale of a mountain belt has rarely been systematically analysed in the past aim of the paper is to present and discuss an inventory map of dsgsd at the scale of the entire european alps in order to review existing knowledge and investigate general controls on these phenomena the criteria adopted for their classification and distinction are presented a total of 1033 dsgsds ranging in size between 0 03 and 108 km 2 have been mapped the inventory has been validated against available local or regional landslide inventories at different scales and prepared by different authors using different approaches the frequency area relationship for the mapped features is presented the spatial distribution of the mapped dsgsd has been quantified by discretizing the study area into regular square grids with different resolution and analysed with respect to a variety of geological geomorpohological and morphometric variables and of their clustering discriminant principal component and cluster analyses have been performed to define the most important controlling and predisposing factors results suggest that the occurrence of foliated metamorphic rocks lgm ice thickness local relief and related parameters slope size drainage density and river stream power are the local parameters most positively correlated to dsgsd occurrence the impact of these phenomena on slope morphology in terms of hypsometry and slope gradient adjustment is also discussed

astrochronology of the early turonian early campanian terrestrial succession in the songliao basin northeastern china and its implication for long period behavior of the solar system abstract the first complete early turonian early campanian lacustrine succession has been recovered from the sk i south sk is borehole in the songliao basin slb northeastern china we conducted a detailed cyclostratigraphic study of natural gamma ray gr log thorium th log and magnetic susceptibility ms data from this core spectral analysis of the upper quantou formation k 2 q 3 4 qingshankou formation k 2 qn yaojia formation k 2 y and lower nenjiang formation k 2 n 1 2 reveals a hierarchy of meter to decameter scale cycling in the data the wavelength ratios of the cycles in these stratigraphic units are 20 5 2 1 corresponding with those of milankovitch cycle periods of 405 kyr long eccentricity 100 kyr short eccentricity 37 kyr obliquity 20 kyr precession indicating astronomical control on sedimentation an astronomical time scale ats was established by tuning interpreted 405 kyr cycles to a 405 kyr orbital eccentricity target curve and to four sims u pb zircon radioisotope ages this absolute ats provides precise numerical ages for stratigraphic boundaries biozones geological and geophysical events and serves as a basis for correlation of strata and events between marine and terrestrial systems the ages of the c33r c34n geomagnetic polarity boundary in k 2 n 2 and three short reversal events in k 2 y are estimated as 83 633 ma 84 819 84 862 ma 84 982 85 092 ma and 85 240 85 629 ma respectively long period amplitude modulations in the obliquity and eccentricity bands of the 405 kyr tuned gr th series provide strong evidence that long period orbital forcing influenced climate change and depositional processes in the slb the extracted amplitude modulations provide evidence that the orbits of earth and mars were not in secular resonance and were undergoing chaotic interactions during this time although the modulations do not match those of recent astronomical models

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

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

chronological constraints on processes leading to large active landslides abstract cosmic ray exposure dating of gravitational scarps along a slope nesting a presently active landslide la clapiere landslide tinee valley argentera massif se france reveal successive periods of gravitational destabilization an initial gravitational destabilization at 10 3 0 5 10 be ka occurs more than 3000 yr after the end of the last deglaciation of the tinee valley dated in the studied area from stoss and lee topography sampled along the tinee and its tributary rabuons valleys a second gravitational destabilization is well constrained at 7 1 0 5 10 be ka through the dating of two gravitational scarps although coincidental with the so called climatic optimum other local or regional triggering factors may be invoked a third evidenced gravitational destabilization occurred 2 3 0 5 10 be ka ago this study thus demonstrates that in situ produced cosmogenic 10 be allows establishing the chronology of gravitational destabilization leading to present major active landslides however in the present case deciphering between the various possible triggering factors will necessitate similar studies on other landslides inside the alpine arc

the temperature of europe during the holocene reconstructed from pollen data we present the first area average time series reconstructions of warmest month coldest month and mean annual surface air temperatures across europe during the last 12 000 years these series are based on quantitative pollen climate reconstructions from over 500 pollen sites assimilated using an innovative four dimensional gridding procedure this approach combines three dimensional spatial gridding with a fourth dimension represented by time allowing data from irregular time series to be focussed onto a regular time step we provide six regional reconstructed temperature time series as well as summary time series for the whole of europe the results suggest major spatial and seasonal differences in holocene temperature trends within a remarkably balanced regional and annual energy budget the traditional mid holocene thermal maximum is observed only over northern europe and principally during the summer this warming was balanced by a mid holocene cooling over southern europe whilst central europe occupied an intermediary position changes in annual mean temperatures for europe as a whole suggest an almost linear increase in thermal budget up to 7800 bp followed by stable conditions for the remainder of the holocene this early holocene warming and later equilibrium has been mainly modulated by increasing winter temperatures in the west which have continued to rise at a progressively decreasing rate up to the present day

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

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

gravitational spreading of mountain ridges coeval with late weichselian deglaciation impact on glacial landscapes in trollaskagi northern iceland abstract during the late weichselian deglaciation the coastal mountains of northern central iceland have experienced significant paraglacial readjustment processes in the form of conspicuous rock slope failures and deep seated gravitational slope deformation dsgsd local topographic slopes and ridges were deeply reshaped by these large scale paraglacial processes located on the eastern side of skagafjor ur one of the largest fjords of northern iceland the oslandshli arfjoll and hnjukar ridges 65 49n 19 14w exhibit geomorphic evidence of spectacular dsgds several series of dsgsd induced landforms such as crestal graben and troughs initiated by ridge top splitting were investigated over a 30 km 2 area on the basis of geomorphological mapping we recognized i a ridge top splitting event mainly controlled by glacial debuttressing induced by a minimal 300 m lowering of the glacier surface in the deildardalur valley ii a rapid late weichselian deglaciation of the deildardalur valley spanning a few thousands of years ice free stage probably reached around 14 000 years cal bp iii ridge top splitting having an influence on large scale glacial patterns by guiding and facilitating glacial erosion along ridge top grabens resulting in accelerated trough widening based on these interpretations we propose an evolutionary sequence of both the kinematic stages of the dsgsd and the late weichselian deglaciation at the valley scale this work provides new insights into i the patterns of the late weichselian deglaciation in the skagafjor ur area especially in tributary valleys of the fjord ii the timing of large scale paraglacial ridge top deformations in relation to the post lgm deglaciation and iii the influence of paraglacial dsgsd features on large scale glacial erosional patterns

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

tectonic vs gravitational morphostructures in the central eastern alps italy constraints on the recent evolution of the mountain range abstract deep seated gravitational slope deformations dsgsds influence landscape development in tectonically active mountain ranges nevertheless the relationships among tectonics dsgsds and topography are poorly known in this paper the distribution of dsgsds and their relationships with tectonic structures and active processes surface processes and topography were investigated at different scales over 100 dsgsds were mapped in a 5000 km2 sector of the central eastern alps between the valtellina engadine and venosta valleys detailed lineament mapping was carried out by photo interpretation in a smaller area about 750 km2 including the upper valtellina and val venosta fault populations were also analysed in the field and their mechanisms unravelled allowing to identify different structural stages the youngest being consistent with the regional pattern of the ongoing crustal deformation finally four dsgsd examples have been investigated in detail by geological and 2d geomechanical modelling dsgsds affect more than 10 of the study area and mainly cluster in areas where anisotropic fractured rock mass and high local relief occur their onset and development is subjected to a strong passive control by mesoscopic and major tectonic features including regional nappe boundaries as well as nw se n s and ne sw trending recent brittle structures the kinematic consistency between these structures and the pattern of seismicity suggests that active tectonics may force dsgsds although field evidence and numerical models indicate slope debuttressing related to deglaciation as a primary triggering mechanism

quaternary gravitational morpho genesis of central apennines italy insights from the mt genzana case history abstract this paper focuses on a study aimed at defining the role of geological structural setting and quaternary morpho structural evolution on the onset and development of a deep seated gravitational slope deformation which affects the western slope of mt genzana ridge central apennines italy this case history is particularly significant as it comprises several aspects of such gravitational processes both in general terms and with particular reference to the apennines in fact i the morpho structural setting is representative of widespread conditions in central apennines ii the deforming slope partially evolved in a large rockslide avalanche iii the deformational process provides evidence of an ongoing state of activity iv the rockslide avalanche debris formed a stable natural dam thus implying significant variations in the morphologic hydraulic and hydrogeological setting v the gravitational deformation as well as the rockslide avalanche reveal a strong structural control the main study activities were addressed to define a detailed geological model of the gravity driven process by means of geological structural geomorphological and geomechanical surveys as a result a robust hypothesis about the kinematics of the process was possible with particular reference to the identification of geological structural constraints the process in fact involves a specific section of the slope exactly where a dextral transtensional structure is present thus implying local structural conditions that favor sliding processes the rock mass is intensively jointed by high angle discontinuity sets and the bedding attitude is quite parallel to the slope angle within this frame the gravitational process can be classified as a structurally constrained translational slide locally evolved into a rockslide avalanche the activation of such a deformation can be in its turn related to the quaternary morphological evolution of the area which was affected by a significant topographic stress increase testified by stratigraphic and morphologic evidence

past hydrological events reflected in holocene history of polish rivers abstract a database of 335 radiocarbon dates from holocene fluvial sediments in poland has been compiled each sample is characterized by 25 parameters all samples were grouped into one of 7 regions characterized by hydrological regime and one of 8 depositional environments statistical analysis was used to enhance the palaeoenvironmental data and 17 phases may be distinguished 10 of which have a distinct sharp peak abandoned paleochannels 149 dates clearly reflect the major wetter phases of the holocene an opposite picture is presented by overbank aggradation 86 dates connected mainly with expansion of agriculture preliminary correlations are made on peat bog records changes in vegetation lake water level rates calcareous tufa and speleothems growth landslides phases and debris flow phases these show many convergences explained by climatic fluctuations during the holocene

paraglacial slope adjustment since the end of the last glacial maximum and its long lasting effects on secondary mass wasting processes hauser kaibling austria abstract this study indicates the possible long lasting impacts of deep seated gravitational slope deformation dgsd on erosional and mass movement processes dgsd features are common large scale landforms in the crystalline basement rocks of the central alps of austria inactive forms are related to paraglacial nonglacial processes directly conditioned by former glaciation and deglaciation rock slope adjustment processes acting after glacier retreat towards the end of the late glacial period the near surface metamorphic bedrock of dgsd features is generally disintegrated such rock type favours erosion and the formation of small landslides field data laboratory analyses aerial photographs and gis based terrain analyses are used to describe the different geomorphic effects of an extremely disintegrated rock slope the studied dgsd hauser kaibling 13 6 km2 is located in central austria during the last glacial maximum the adjacent valley glacier reached an altitude of approximately 1900 m a s l glacier retreat in combination with the unfavourable tectono metamorphic setting caused gravity induced stresses to act subsequent sediment build up in the main valley restabilised the slope linear erosion cut a number of gullies into the lower part of the dgsd calculated mean erosional denudation rates at incised valley sections range from 0 5 to 2 6 mm a 1 since deglaciation smaller active landslides on the sides of the steep gullies draining the dgsd contribute to high denudation rates active landsliding is favoured by i fragmented rock ii steep slopes iii supply of surface and subsurface water by rain and snowmelt and iv human impact debris flows and debris charged flood events occurred frequently in the past during such events material was transported from the unstable slopes to the populated alluvial fans thus knowledge about the spatial distribution and the stage of development of dgsds active and currently inactive provides an important basis for risk management measures