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

geomorphology and age of the marocche di dro rock avalanches trentino italy abstract the marocche di dro deposits in the lower sarca valley are some of the most distinctive rock avalanche deposits of the alps we use geomorphology and cosmogenic 36 cl exposure dating of boulders to divide the marocche di dro deposits into two rock avalanche bodies the marocca principale to the north and the kas to the south the deposits were previously undated and had been mapped as up to five different events the largest event marocca principale which comprises an estimated 1000 10 6 m 3 of predominantly rotzo formation limestones occurred 5300 860 yr ago the release area is located mainly in the alcove between mt casale and mt granzoline but likely extends all the way to mt brento the kas event took place 1080 160 yr ago with detachment below mt brento the kas debris with an estimated volume of 300 10 6 m 3 buried the southern third of the marocca principale deposit kas presents a barren stark landscape dominated by house sized tovel member rotzo formation boulders bearing distinctive chert lenses both the extreme relief of the rock wall more than 1300 m and the tectonic setting predispose the range front to massive failure for the two events initially translational movement likely quickly evolved into complex failure and massive collapse run out across the valley of several kilometers and run up on the opposite slope of hundreds of meters followed a summary of all dated and large historical landslides in the alps underlines the periods of enhanced slope activity discussed in the literature 10 9 kyr 5 3 kyr and 2 1 kyr the latter especially for the southern alps no deposits of the first temporal cluster are found at marocche di dro the age of marocca principale at 5300 860 yr suggests occurrence during the second period failure may have been related to the shift to wetter colder climate at the transition from the middle to the late holocene nevertheless a seismic trigger cannot be ruled out for the kas rock avalanche at 1080 160 yr ago we implicate the middle adige valley 1046 ce earthquake as trigger its epicentral distance is much closer to the sarca valley in comparison to that of the verona earthquake 1117 ce

contribution a l analyse de la deformation et de la rupture des grands versants rocheux en terrain cristallophyllien in mountainous regions the study of the stability of rock slopes is of major importance for land management and safety of populations the monitoring of several unstable alpine slopes has shown th

the application of advanced space borne thermal emission and reflection aster radiometer data in the detection of alteration in the chadormalu paleocrater bafq region central iran abstract ore deposits are often produced by fluid flow processes that alter the mineralogy and chemistry of the country rock one of the main objectives in developing a multi spectral and hyperspectral sensor is to detect the optical characteristics of the earth s surface using hundreds of spectral bands all previous studies show that remote sensing can recognize alteration to different degrees using different spatial and spectral resolution sensors the aster sensor measures reflected radiation in vnir swir and tir electromagnetic energies it is cheap and easily available the alteration minerals in the precambrian chadormalu area chadormalu paleocrater and the related iron oxide deposit have been investigated in the field and have been successfully detected by applying iarr internal average relative reflectance fcc false color composite decorrelation stretch mnf minimum noise fraction transform correlated filter and mem mathematical evaluation method techniques on aster imageries sodic potassic and silicic phyllic alteration patterns can be distinguished this study shows that the capability and accuracy of the mem method is better than 2 2 correlated filter techniques results indicate that pervasive hydrothermal ore forming processes were important in the study area judging from the assemblage of alteration minerals the chadormalu iron deposit is an end member of the kiruna type iron oxide cu au ore deposit continuum

landslides and quaternary climate changes the state of the art abstract climatic factors are considered major causes and triggers of slope instability but the palaeoclimatic implications of landslides have not yet been systematically reviewed as inferred from landslides dated to the late glacial and holocene glacial interglacial transitions are the major intervals of enhanced landsliding but the length of this interval varies between distinct types of landscapes mass movements in non glaciated temperate mountain ranges arid and tropical regions and coastal areas intensified soon after the onset of the holocene alongside the warming and wetting of the climate whereas large rock slides in areas within the limits of pleistocene glaciations mostly show a millennial scale time lag with respect to glacier withdrawal although the incidence of landslides was ubiquitous throughout the holocene the mid to late holocene transition 5 4 ka was especially favourable for the origin of landslides across distinct types of landscapes indicating a strengthened role of mass movements during the culmination phases of interglacial climate optima in addition growing evidence suggests that the enhanced activity of landslides occurred during warmer interstadial conditions which is best demonstrated in the temporal coincidence of arid zone landslides with quaternary pluvials future progress in the understanding of the relationships between landslides and quaternary climate changes should benefit from the i extension of datasets of dated landslides ii geographical expansion of dating studies to regions with a lack of chronologically determined landslides e g tropics iii improvement of landslide dating strategies involving the incorporation of independent palaeoclimatic proxies and iv wider incorporation of numerical modeling within landslide dating studies

estimation of slip rates in the southern tien shan using cosmic ray exposure dates of abandoned alluvial fans cosmic ray exposure dates based on in situ produced 10 be in combination with measured heights of fault scarps that cut three abandoned fans imply a slip rate of less than 2 mm yr on the bounding thrust fault along a segment of the southern flank of the tien shan of central asia this rate somewhat lower than those for the segment farther west and for the northern margin of the belt implies that the distribution of shortening across the tien shan must change markedly along the belt the date of abandonment of the smallest of the three fans is consistent with fan formation since the last glacial maximum but the other two fans appear to have been formed and abandoned prior to that time these and other results suggest that advances and retreats of alpine glaciers may not be synchronized with continental ice sheets and that not all prominent geomorphological features in arid asian regions have formed since the last glacial maximum in this study we have assessed the relationship between cosmogenic nuclide content of individual clasts and the time since their deposition on a surface cosmogenic nuclide accumulation represents the integrated total surface exposure of rocks in source regions during transport and since deposition postdepositional processes erosion burial bioturbation and cryoturbation all of which decrease the quantity of cosmogenic nuclides produced in a rock in a given time and hence the apparent exposure age also cause significant scatter among apparent ages of samples from the surfaces very low 10 be concentrations in material from active streambeds and at depth below one of the fan surfaces indicate that exposure prior to deposition onto fan surfaces was minimal

toward automated delineation of ground penetrating radar facies in clastic sediments an example from stratified glaciofluvial deposits abstractground penetrating radar gpr is an established geophysical method to explore near surface sedimentary environments interpreting gpr images is largely based on manual procedures following concepts known as gpr facies analysis we have developed a novel strategy to distinguish gpr facies in a largely automated and more objective manner first we calculate 13 textural attributes to quantify gpr reflection characteristics then this database is reduced using principal component analysis finally we image the dominating principal components using composite imaging and classify them using standard clustering methods the potential of this workflow is evaluated using a 2d gpr field example collected across stratified glaciofluvial deposits our results demonstrate that the derived facies images are well correlated with the composition and the porosity of the sediments as known from independent borehole logs our analysis strategy eases and improves the interpretability of gpr data and will help in

cosmic ray exposure dating on the large landslide of sechilienne western alps a synthesis to constrain slope evolution abstract the 60 10 6 m 3 sechilienne landslide belledonne massif western alps is located on the right bank of the east west trending romanche valley which is shaped by glacial and alluvial processes during the quaternary its head scarp 35 m high was dated by le roux et al 2009 using the cosmic ray exposure cre method even though these previous results revealed that the initiation of the instability occurred several thousand years after ice down wastage in the valley the internal landslide evolution is not constrained in this paper we provide 63 additional 10 be samples collected from the internal scarps and the main scarp as well as on glacially polished rock surfaces the aim is to constrain the global landslide kinematics internal and head scarps and its relationship with glacier retreat results from glacially polished surfaces point out that complex shielding processes relict moraines soil deposits and seasonal snow cover might have affected rock dating despite scattering of the resulting ages the dataset shows that the glacial retreat was achieved between 17 5 and 13 ka exposure ages obtained on gravitational scarps reveal that the landslide initiation occurred 8 to 6 ka ago from the initiation until 2 ka the gravitational kinematics was slow 2 mm year 1 and focused around the head scarp leading to a general slope subsidence after 2 ka the exposure rates increased significantly 8 mm year 1 with the development of pervasive internal deformation of the landslide mass this new scenario for the sechilienne slope reflects a progressive rock slope weakening since 8 ka associated with a continuous activity of a deep seated surface failure

lake sediments deposited on the flims rockslide mass the key to date the largest mass movement of the alps long piston cores taken from the subsurface of two mountain lakes of the eastern swiss alps recovered sediments which overlie the flims rockslide deposits these sediments provide new information on the chronology of the largest known alpine rockslide and can be used to reconstruct the post landslide environmental evolution the oldest 14 c date of the lake sediments yields a minimum age of the rockslide at 9660 9430 cal yr bp in addition the dating of a wood fragment contained in the rockslide deposits directly below the lake sediments shows a maximum age of 9480 9120 cal yr bp the overlap of the maximum and minimum ages 9480 9430 cal yr bp approximates the age of the flims rockslide this early holocene range coincides with a period of higher frequency of large mass movements observed in the alps which could be related to climatic changes

field characterization and data integration to define the hydraulic heterogeneity of a shallow granular aquifer at a sub watershed scale providing a sound basis for aquifer management or remediation requires that hydrogeological investigations carried out to understand groundwater flow and contaminant transport be based on representative data that capture the heterogeneous spatial distribution of aquifer hydraulic properties this paper describes a general workflow allowing the characterization of the heterogeneity of the hydraulic properties of granular aquifers at an intermediate scale of a few km2 the workflow involves characterization and data integration steps that were applied on a 12 km2 study area encompassing a decommissioned landfill emitting a leachate plume and its main surface water receptors the sediments composing the aquifer were deposited in a littoral sublittoral environment and show evidence of small scale transitional heterogeneities cone penetrometer tests cpt combined with soil moisture and electrical resistivity smr measurements were thus used to identify and characterize spatial heterogeneities in hydraulic properties over the study area site specific statistical relationships were needed to infer hydrofacies units and to estimate hydraulic properties from high resolution cpt smr soundings distributed all over the study area a learning machine approach was used due to the complex statistical relationships between colocated hydraulic and cpt smr data covering the full range of aquifer materials application of this workflow allowed the identification of hydrofacies units and the estimation of horizontal hydraulic conductivity vertical hydraulic conductivity and porosity over the study area the paper describes and discusses data acquisition and integration methodologies that can be adapted to different field situations while making the aquifer characterization process more time efficient and less labor intensive

vertical radar profiling combined analysis of traveltimes amplitudes and reflections abstractvertical radar profiling vrp is a single borehole geophysical technique in which the receiver antenna is located within a borehole and the transmitter antenna is placed at one or various offsets from the borehole today vrp surveying is primarily used to derive 1d velocity models by inverting the arrival times of direct waves using field data collected at a well constrained test site in germany we evaluated a vrp workflow relying on the analysis of direct arrival traveltimes and amplitudes as well as on imaging reflection events to invert our vrp traveltime data we used a global inversion strategy resulting in an ensemble of acceptable velocity models and thus it allowed us to appraise uncertainty issues in the estimated velocities as well as in porosity models derived via petrophysical translations in addition to traveltime inversion the analysis of direct wave amplitudes and reflection events provided further valuable information regarding subsurface properties and architecture the

location and geometry of the wellington fault new zealand defined by detailed three dimensional georadar data 1 earthquakes with surface wave magnitudes of 7 3 7 9 are estimated to be associated with the rupture of the wellington fault at relatively regular intervals of 500 770 years the last such earthquake probably happened between ad 1510 and 1660 along its southern segment the wellington fault passes through wellington new zealand s capital and the densely populated hutt valley it is considered to be a highly hazardous structure to map the shallow geometry of the wellington fault we have collected 3 d ground penetrating radar georadar data at two sites along the fault in the hutt valley at one site the first ever georadar fault plane reflections from an active strike slip fault are observed they coincide with conspicuous diffractions generated by abrupt truncations of structures against the fault plane these georadar data provide the most vivid shallow images of any active fault surveyed to date at the second site apparent offsets of lineaments in the sedimentary sections on either side of the fault are consistent with 20 m of dextral displacement estimated from the offset of a nearby terrace riser the dips and minimum depth extents of the primary zones of fault displacement at the two sites are 55 75 se and 20 m and 72 84 se and 12 m respectively although the georadar defined zones of faulting are a few meters wide prominent reflection fabrics suggest that shearing fracturing and crushing extend for several tens of meters on either side of the fault

application of geophysical methods for the investigation of the large gravitational mass movement of sechilienne france several geophysical techniques electromagnetic profiling electrical tomography seismic refraction tomogra phy and spontaneous potential and seismic noise measurement were applied in the investigation of the large gravita tional mass movement of sechilienne france the aim of this study was to test the ability of these methods to characterize and delineate the rock mass affected by this complex movement in mica schists whose lateral and vertical limits are still uncertain a major observation of this study is that all the zones strongly deformed previously and at present by the movement are characterized by high electrical resistivity values 3 k m in contrast to the undis turbed mass which exhibits resistivity values between a few hundred and 1 k m as shown by the surface observa tions and the seismic results this resistivity increase is due to a high degree of fracturing associated with the creation of air filled voids inside the mass other geophysical techniques were tested along a horizontal transect through the movement and an outstanding coherency appeared between the geophysical anomalies and the displacement rate curve these preliminary results illustrate the benefits of combined geophysical techniques for characterizing the rock mass in volved in the movement results also suggest that monitoring the evolution of the rock mass movement with time lapse geophysical surveys could be beneficial resume plusieurs techniques geophysiques profil electromagnetique tomographie electrique tomographie sismique et potentiel spontane et bruit de fond sismique ont ete appliquees pour la reconnaissance du grand mouvement de ter rain de sechilienne france situe dans des micaschistes l objectif de cette etude etait de tester ces methodes geophy siques afin de caracteriser et de delimiter la masse de roche affectee par ce mouvement complexe dont la limite laterale reste incertaine l etude a montre que toutes les zones tres deformees encore actuellement et dans le passe par le mouvement sont caracterisees par de fortes valeurs de resistivite electrique superieur ea3k m tandis que dans la zone non perturbee les valeurs de resistivite sont de quelques centaines de m a1k m comme le montrent les observations de surface et les profils de tomographie sismique cette augmentation de resistivite est due a une frac turation importante associee a la creation de vides remplis d air au sein du massif les techniques electromagnetiques ps et de mesure de bruit ont ete testees le long d un profil transversal recoupant le mouvement une correlation remar quable est obtenue entre les anomalies geophysiques et le taux de deplacement ces resultats preliminaires soulignent l interet de combiner les methodes geophysiques pour caracteriser la masse de roche impliquee dans le mouvement et pour determiner l evolution du mouvement par un suivi temporel des parametres geophysiques mots cles mouvement gravitaire methodes geophysiques sechilienne meric et al 1115

the largest prehistoric landslide in northwestern slovakia chronological constraints of the kykula long runout landslide and related dammed lakes abstract this study deals with the chronology of the largest long runout landslide in the northwesterrn part of the western flysch carpathians kysucke beskydy mts slovakia despite the impossibility of using direct radiocarbon dating method time constraints for the evolution of the landslide were determined on the basis of the dating of various sedimentological geomorphological elements situated on and adjacent to the landslide body the results show that the landslide evolved between 10 3 and 9 0 ka 14 c bp i e in the wider transitional phase between the late glacial lg and the holocene the main mass movement activity took place at the turn of the younger dryas preboreal chronozones whereas retrogressive activity continued up to the preboreal boreal transition radiocarbon dating together with pollen analysis and sedimentology of landslide dammed palaeolakes and colluvial peat bogs revealed almost continuous holocene palaeogeographical records between 10 3 and 3 3 ka 14 c bp periods of enhanced sediment supply to the reservoirs in 9 9 9 0 8 4 8 2 6 9 6 5 and 4 5 ka 14 c bp correlate well with palaeogeomorphic and palaeohydrological records from nearby polish carpathians the study confirms that the lg holocene transition represented a favourable period for the evolution of large landslides not only in glaciated high mountain areas but also in medium high mountains of central europe

mid holocene cluster of large scale landslides revealed in the southwestern alps by 36cl dating insight on an alpine scale landslide activity abstract although it is generally assumed that the internal structure of a slope e g lithology and rock mass properties inherited faults and heterogeneities etc is preponderant for the progressive development of large scale landslides the ability to identify triggering factors responsible for final slope failures such as glacial debuttressing seismic activities or climatic changes especially when considering landslide cluster at an orogen scale is still debated highlighting in this study the spatial and temporal concordant clustering of deep seated slope failures in the external southwestern alps we discuss and review the possible causes for such wide spread slope instabilities at both local and larger alpine scale high resolution field mapping coupled with electrical resistivity tomography first allows establishing an inventory of large landslides in the southwestern alps determining their structural model precising their depth limit 100 200 m as well as the involved rock volumes 10 7 m 3 we show that they developed in the same geostructural context of thick mudstone layers overlain by faulted limestone and followed a block spread model of deformation that could evolve in rock collapse events cosmic ray exposure dating cre using both 36 cl and 10 be in coexisting limestone and chert respectively has been carried out from the main scarps of six deep seated landslides dsl and leads to landslide failure cre ages ranging from 3 7 to 4 7 ka they highlighted i mainly single and fast ruptures and ii a possible concomitant initiation with a main peak of activity between 3 3 and 5 1 ka centered at ca 4 2 ka because this region was not affected by historical glaciations events landslide triggering by glacial unloading can be excluded the presented data combined with field observations preferentially suggest that these failures were climatically driven and were most likely controlled by high pressure changes in the karstic medium in effect the chronicle of failure ages is concomitant to a well known climatic pulse the 4 2 ka climate event characterized by intense hydrological perturbations associated to the heaviest rainfall period of the entire holocene despite requiring further investigations and discussions the dating of numerous events across the entire alps during the middle holocene period suggests a potential synchronous triggering of several large scale gravitational failures induced by the mid holocene climatic transition

hydrogeological characterization of the south oyster bacterial transport site using geophysical data a multidisciplinary research team has conducted a field scale bacterial transport study within an uncontaminated sandy pleistocene aquifer near oyster virginia the overall goal of the project was to evaluate the importance of heterogeneities in controlling the field scale transport of bacteria that are injected into the ground for remediation purposes geochemical hydrological geological and geophysical data were collected to characterize the site prior to conducting chemical and bacterial injection experiments in this paper we focus on results of a hydrogeological characterization effort using geophysical data collected across a range of spatial scales the geophysical data employed include surface ground penetrating radar radar cross hole tomography seismic cross hole tomography cone penetrometer and borehole electromagnetic flowmeter these data were used to interpret the subregional and local stratigraphy to provide high resolution hydraulic conductivity estimates and to provide information about the log conductivity spatial correlation function the information from geophysical data was used to guide and assist the field operations and to constrain the numerical bacterial transport model although more field work of this nature is necessary to validate the usefulness and cost effectiveness of including geophysical data in the characterization effort qualitative and quantitative comparisons between tomographically obtained flow and transport parameter estimates with hydraulic well bore and bromide breakthrough measurements suggest that geophysical data can provide valuable high resolution information this information traditionally only partially obtainable by performing extensive and intrusive well bore sampling may help to reduce the ambiguity associated with hydrogeological heterogeneity that is often encountered when interpreting field scale bacterial transport data

coastal cliffs rock slope failures and late quaternary transgressions of the black sea along southern crimea abstract rock slope failures represent a significant hazard along global coastlines but their chronology remains poorly documented here we focus on the geomorphology and chronology of giant rockslides affecting the crimean mountains along the black sea coast geomorphic evidence suggests that high 100 m limestone cliffs flanking the southern slopes of the crimean mountains are scarps of rockslides nested within larger deep seated gravitational slope deformations dsgsds such pervasive slope failures originated due to lateral spreading of intensively faulted late jurassic carbonate blocks moving atop weak plastic late triassic flysch and tuff layers by introducing a dating strategy relying on the combination of the uranium thorium dating u th of exposed calcareous speleothems covering the landslide scarps with the 36cl exposure dating of rock walls we are able to approximate the time interval between the origin of incipient crevices and the final collapse of limestone blocks that exposed the cliff faces for the three representative large scale rockslides between the towns of foros and yalta the initiation of the dsgsds as evidenced by the widening of crevices and the onset of speleothem accumulation was 300 ka bp but the recent cliff morphology along the coast is the result of late pleistocene holocene failures spanning 20 0 5 ka bp the exposures of rockslide scarps occurred mostly at 20 15 8 5 4 and 2 0 5 ka which substantially coincide with the last major black sea transgressions and or more humid holocene intervals our study suggests that before ultimate fast and or catastrophic slope failures the relaxation of rock massifs correlative with karstification cracks opening and incipient sliding lasted on the order of 104 105 years rapid late glacial holocene transgressions of the black sea likely represented the last impulse for the collapse of limestone blocks and the origin of giant rockslides simultaneously affecting the majority of the sw coast of the crimean peninsula

tracing tsunami signatures of the ad 551 and ad 1303 tsunamis at the gulf of kyparissia peloponnese greece using direct push in situ sensing techniques combined with geophysical studies

three dimensional hydrostratigraphic models from ground penetrating radar and direct push data abstract three dimensional models of hydraulic conductivity and porosity are essential to understand and simulate groundwater flow in heterogeneous geological environments however considering the inherent limitations of traditional hydrogeological field methods in terms of resolution alternative field approaches are needed to establish such 3 d models with sufficient accuracy in this study we developed a workflow combining 3 d structural information extracted from ground penetrating radar gpr images with 1 d in situ physical property estimates from direct push dp logging to construct a 3 d hydrostratigraphic model to illustrate this workflow we collected an 70 m 90 m 100 mhz 3 d gpr data set over a shallow sedimentary aquifer system resolving six different gpr facies down to 15 m depth dp logs of the relative dielectric permittivity the relative hydraulic conductivity the cone resistance the sleeve friction and the pore pressure provided crucial data 1 to establish a gpr velocity model for 3 d depth migration and to check the time to depth conversion of the gpr data and 2 to construct a 3 d hydrostratigraphic model this model was built by assigning porosity values which were computed from the dp relative dielectric permittivity logs and dp relative hydraulic conductivity estimates to the identified gpr facies we conclude that the integration of 3 d gpr structural images and 1 d dp logs of target physical parameters provides an efficient way for detailed 3 d subsurface characterization as needed for example for groundwater flow simulations

processes of slope failure in crystallophyllian formations abstract major slope movement is a common feature of the crystalline and crystallophyllian ranges of the alps beginning towards the end of the ice age these movements have not necessarily led to slope failure but are continuing to evolve today following a cyclic pattern and may be a potential source of danger for human activities a complex set of factors has to be taken into account in any study of such phenomena particularly in attempting to predict when the final crisis will occur a particular feature of crystallophyllian massifs is their pre existing anisotropic structure schistosity metamorphic foliation in which weakness planes give rise to mechanical anisotropy to analyse the failure processes that may occur in such a context and affect an entire mountain slope the authors consider several examples most of which are located in the french alps the study is based mainly on surface observations

on the use of combined geophysical methods to assess water content and water conductivity of near surface formations abstract we propose to deepen the interpretation of combined geophysical methods georadar seismic and electric to assess physical properties characterizing the near surface porous formations especially the influence of water velocity analysis of multioffset georadar data are used together with seismic methods to estimate lateral and vertical ground water fluctuations this enables us to identify transitions from non saturated to fully saturated porous layers with certainty furthermore the accurate knowledge of seismic velocities helps to estimate the porosity of the ground water formations finally we show how the radar technique may be useful in solving the problem of trade off between bulk resistivity which is deduced from electrical measurements and that of water ionic conductivity and water content these theoretical considerations are illustrated using various measurements conducted at the same test site our interpretation is compared with a few laboratory measurements on water and soil samples this study displays the impact of combined geophysical approaches for providing models of water and ionic transfers down to a depth of several metres

hydrogeologic facies models to delineate large scale spatial trends in glacial and glaciofluvial sediments recent interest in contaminant transport in ground water has led hydrogeologists to the conclusion that predicting the movement of solutes requires information on the distribution of spatial trends and heterogeneities in porous media description of spatial trends has long been of interest to sedimentologists who have produced a large body of geologic information on the subject in this paper facies models are used to construct conceptual models of hydrogeologic facies for glacialmeltwater stream sediment and till these hydrogeologic facies models which delineate large scale trends in heterogeneity are appropriate for use in designing hydrogeologic field tests and for estimating input to regional ground water flow and transport models this paper treats each facies as a homogeneous anisotropic hydrogeologic unit the models presented herein conceptualize the hydrogeologic relationships among facies and illustrate one method of converting the apparent chaos in nature into an orderly system that can be tested scientifically and modeled mathematically the principles used to create conceptual models of hydrogeologic facies for the types of sediment considered in this paper can be extended to other sedimentary environments it should be recognized however that such models do not address the small scale heterogeneity present within individual facies additional basic research is required to measure hydraulic conductivity variation within representative hydrogeologic facies and to develop statistical descriptions to represent the variations such detailed descriptions of hydraulic conductivity may be necessary to describe ground water flow at a local scale for analysis of contaminant transport

soil moisture content estimation using ground penetrating radar reflection data abstract ground penetrating radar gpr reflection travel time data were used to estimate changes in soil water content under a range of soil saturation conditions throughout the growing season at a california winery data were collected during three data acquisition campaigns over an 80 by 180 m area using 100 mhz surface gpr antennas gpr reflections were associated with a thin low permeability clay layer located 0 8 1 3 m below the ground surface that was identified from borehole information and mapped across the study area field infiltration tests and neutron probe logs suggest that the thin clay layer inhibited vertical water flow and was coincident with high volumetric water content vwc values the gpr reflection two way travel time and the depth of the reflector at the borehole locations were used to calculate an average dielectric constant for soils above the reflector a site specific relationship between the dielectric constant and vwc was then used to estimate the depth averaged vwc of the soils above the reflector compared to average vwc measurements from calibrated neutron probe logs over the same depth interval the average vwc estimates obtained from gpr reflections had an rms error of 0 018 m3 m 3 these results suggested that the two way travel time to a gpr reflection associated with a geological surface could be used under natural conditions to obtain estimates of average water content when borehole control is available and the reflection strength is sufficient the gpr reflection method therefore has potential for monitoring soil water content over large areas and under variable hydrological conditions

effects of tectonic structures and long term seismicity on paraglacial giant slope deformations piz dora switzerland abstract the interplay of tectonic and climatic forcing in the development of alpine deep seated gravitational slope deformations dsgsd is still poorly understood we investigate a giant dsgsd affecting the piz dora slope val mustair switzerland by geological structural and geomorphological analyses spaceborne sar interferometry and numerical modelling the dsgsd affects permian terrigenous and volcanoclastic successions folded into a kilometre scale asymmetric anticline during the alpine orogenesis the area is characterized by active tectonic uplift and widespread shallow seismicity with dominant dip slip fault mechanisms experienced fast deglaciation after the last glacial maximum and periglacial conditions between the lateglacial and holocene the slope is affected by morpho structural features testifying to the deep seated gravitational sliding of 1 85 km3 of rock along a basal shear zone over 400 m deep analysis of rock glaciers and dinsar data show that the dsgsd was active in lateglacial times and is presently deforming at rates o 15 mm yr integrated kinematic analysis of field and radar data outlines a key control of the inherited fold structure on the dsgsd with a transition from deep compound sliding to the west controlled by massive conglomerates chazfora formation to shallower roto translational sliding to the east controlled by volcanoclastic foliated rocks ruina formation 2dfem stress strain numerical models simulating the post lgm slope evolution in static pseudo static and dynamic conditions allowed evaluating the contribution of long term seismicity to dsgsd in a paraglacial setting dynamic modelling was performed starting from the characterization of a real earthquake representative of the recent local seismotectonic activity and scaled to obtain dynamic scenarios with different return periods results suggest that deglaciation related perturbations promoted the inception of the dsgsd but not its complete development that was likely stimulated by the long term contribution of recurrent small earthquakes our results suggest that inherited structures active seismicity and deglaciation cooperate to promote paraglacial rock slope deformation in tectonically active alpine settings

examination of surface exposure ages of antarctic moraines using in situ produced 10be and 26al concentrations of 10be t12 1 5 106 y and 26a1 t12 0 72 106 y have been determined by accelerator mass spectrometry ams in a suite of quartz samples taken from sandstone boulders in several moraines in arena valley a dry valley adjacent to the taylor glacier in the quatermain mountains southern victoria land east antarctica these isotopes are produced in surficial quartz by cosmic ray spallation of o and si the concentrations in these samples ranged from 6 1 105 to 3 0 107 at g 1 for 10be and from 9 4 106 to 1 2 108 at g 1 for 26a1 depending upon the extent of exposure at the surface analyses of 10be in several samples from a single moraine at altitudes ranging from 1300 to 1650 m permitted an estimation of the air attenuation pathlength of cosmic ray neutrons the value of 142 96 41 g cm 2 is consistent with other published values production rates of 17 6 4 at g 1 y 1 for 10be and 113 54 16 at g 1 y 1 for 26a1 at 1300 m and 87 s and a 26al 10be production ratio of 6 5 1 3 1 3 were calculated from the data these values correspond to sea level production rates at high geomagnetic latitude of 6 4 at g 1 y 1 and 41 7 at g 1 y 1 for 10be and 26a1 respectively consistent with determinations based on 11 ky glacially polished surfaces in the sierra nevada in california these production rates imply exposure ages for the various moraines ranging from 50 ky to 2 5 my in accordance with other geological evidence the 10be and 26al ages of these rocks compare favorably with those found using a similar dating method based on in situ production of 3he examination of the 3he concentrations in conjunction with the present data set yields an estimate of 3he production of 230 8540 at g 1 y 1 corresponding to 85 31 15 at g 1 y 1 at sea level this is lower than previously reported values of 240 60 at g 1 y 1 and 190 at g 1 y 1 scaled to sea level and high geomagnetic latitude based respectively on volcanic flows less than 2000 years old at low latitude and samples collected from 14 400 year old volcanic flows this discrepancy is likely due to diffusive losses which may become significant up to 50 for surface exposure ages on the order of 2 0 my nevertheless the general correlations among the three isotopes suggest that 3he does not suffer gross losses through diffusion

the landslide response of alpine basins to post little ice age glacial thinning and retreat in southwestern british columbia abstract the role of post little ice age lia neoglacial retreat on landslide activity is investigated in 19 alpine basins along the upper lillooet river valley british columbia we examine how neoglacial scouring and glacial recession have modified hillslope form and slope stability and construct a decision making flowchart to identify landslide hazards associated with glacial retreat this work is based on field mapping gis analysis statistical associations between landslides and terrain attributes and a comparison between neoglaciated and non neoglaciated terrain within each basin the bedrock landslide response to glacial retreat varies appreciably according to lithology and the extent of glacial scour below the lia trimline valleys carved in weak quaternary volcanics show significant erosional oversteepening and contain deep seated slope movement features active rock fall rock slides and rock avalanches near glacial trimlines basins in stronger granitic rock rarely show increased bedrock instability resulting from post lia retreat except for shallow seated rock slides along some trimlines and failures on previously unstable slopes in surficial materials landslides associated with post lia retreat originate in till or colluvium as debris slides or debris avalanches and are concentrated along lateral moraines or glacial trimlines significant spatial association was also observed between recent catastrophic failures gravitational slope deformation and slopes that were oversteepened then debuttressed by glacial erosion eight out of nine catastrophic rock slope failures occurred just above glacial trimlines and all occurred in areas with a previous history of deep seated gravitational slope movement implying that this type of deformation is a precursor to catastrophic detachment

mapping lithology of the sarfartoq carbonatite complex southern west greenland using hymap imaging spectrometer data the sarfartoq carbonatite complex occurs in the southern west greenland in a transition zone between archaean gneiss complex to the south and a proterozoic mobile belt to the north the sarfartoq carbonatite complex consists of a core zone composed of dolomite carbonatite and minor sovite calcite carbonatite surrounded by a fenite zone and a marginal zone of gneisses frequently altered due to hydrothermal activity high spatial and spectral resolution imaging spectrometer data recorded by the hymap imaging system were used to map lithology of the sarfartoq carbonatite complex a careful analysis of the spectral reflectance properties of the carbonatite lithology preceded the hymap data analysis stage the spectral reflectance measurements showed that the various lithologic units including dolomite carbonatite sovite fenite and the marginal alteration zone have distinct spectral reflectance characteristics the analysis of the hymap data was based on an unsupervised clustering algorithm the self organizing maps som for the mapping of the main lithology and a hierarchical tree for the mapping of sparsely occurring sovite rocks spectral mixture analysis was applied to map fractional abundances and compare with the som results the resulting lithological map shows the spatial distribution of dolomite carbonatite sovite fenite with abundant carbonatite dykes representing the outer core of the carbonatite complex fenite and hematized gneiss marginal alteration zone the results compare well with the field data collected for the assessment of the mapping accuracy and due to the spatially contiguous nature of the hyperspectral data could be used to better map the outcropping carbonatite lithology the spectral reflectance measurements and the mapping results provide information of petrological importance for the carbonatite core zone

spectral reflectance of carbonatites and related alkalic igneous rocks selected samples from four north american localities laboratory spectral reflectance measurements were made in the 0 4 to 2 5 mu m wavelength range for samples collected from four north american carbonatite alkalic igneous rock complexes alkalic rock spectra produced few absorption features however the carbonatites typically showed conspicuous carbonate ferric and ferrous iron and in some cases rare earth element absorption bands trivalent neodymium was the most abundant rare earth element producing absorption features and could be detected in amounts as low as 300 ppm ferrous iron was present in most dolomitic carbonatite samples and caused more intense ferrous absorption bands than commonly is seen in carbonate rocks of sedimentary origin high carbonatite iron content also resulted in pervasive limonitic staining and related ferric iron absorption features these absorption features sometimes masked other absorption bands because reflectance measurements can be carried out rapidly with minimal sample preparation reflectance spectroscopy may provide a useful field and laboratory tool for analyzing economic rare earth concentrations in addition the distinctive spectral characteristics of carbonatite material in conjunction with the discordant spatial relationships between associated alkalic and carbonatite rocks may provide a basis for remote sensing detection of these complexes

high resolution aquifer characterization using crosshole gpr full waveform tomography comparison with direct push and tracer test data limited knowledge about the spatial distribution of aquifer properties typically constrains our ability to predict subsurface flow and transport here we investigate the value of using high resolution full waveform inversion of cross borehole ground penetrating radar gpr data for aquifer characterization by stitching together gpr tomograms from multiple adjacent crosshole planes we are able to image with a decimeter scale resolution the dielectric permittivity and electrical conductivity of an alluvial aquifer along cross sections of 50 m length and 10 m depth a logistic regression model is employed to predict the spatial distribution of lithological facies on the basis of the gpr results vertical profiles of porosity and hydraulic conductivity from direct push flowmeter and grain size data suggest that the gpr predicted facies classification is meaningful with regard to porosity and hydraulic conductivity even though the distributions of individual facies show some overlap and the absolute hydraulic conductivities from the different methods direct push flowmeter grain size differ up to approximately one order of magnitude comparison of the gpr predicted facies architecture with tracer test data suggests that the plume splitting observed in a tracer experiment was caused by a hydraulically low conductive sand layer with a thickness of only a few decimeters because this sand layer is identified by gpr full waveform inversion but not by conventional gpr ray based inversion we conclude that the improvement in spatial resolution due to full waveform inversion is crucial to detect small scale aquifer structures that are highly relevant for solute transport

beryllium 10 dating of the duration and retreat of the last pinedale glacial sequence accurate terrestrial glacial chronologies are needed for comparison with the marine record to establish the dynamics of global climate change during transitions from glacial to interglacial regimes cosmogenic beryllium 10 measurements in the wind river range indicate that the last glacial maximum marine oxygen isotope stage 2 was achieved there by 21 700 700 beryllium 10 years and lasted 5900 years ages of a sequence of recessional moraines and striated bedrock surfaces show that the initial deglaciation was rapid and that the entire glacial system retreated 33 kilometers to the cirque basin by 12 100 500 beryllium 10 years

time constraints for post lgm landscape response to deglaciation in val viola central italian alps abstract across the northern european alps a long tradition of quaternary studies has constrained post lgm last glacial maximum landscape history the same picture remains largely unknown for the southern portion of the orogen in this work starting from existing 10be exposure dating of three boulders in val viola central italian alps we present the first detailed post lgm reconstruction of landscape i e glacial periglacial and paraglacial response south of the alpine divide we pursue this task through schmidt hammer exposure age dating shd at 34 sites including moraines rock glaciers protalus ramparts rock avalanche deposits and talus cones in addition based on the mapping of preserved moraines and on the numerical shd ages we reconstruct the glacier extent of four different stadials including egesen i 13 1 1 1 ka egesen ii 12 3 0 6 ka kartell 11 0 1 4 ka and kromer 9 7 1 4 ka whose chronologies agree with available counterparts from north of the alpine divide results show that equilibrium line altitude depressions elas associated to younger dryas and early holocene stadials are smaller than documented at most available sites in the northern alps these findings not only support the hypothesis of a dominant north westerly atmospheric circulation during the younger dryas but also suggest that this pattern could have lasted until the early holocene shd ages on rock glaciers and protalus ramparts indicate that favourable conditions to periglacial landform development occurred during the younger dryas 12 7 1 1 ka on the valley slopes above the glacier as well as in newly de glaciated areas during the early holocene 10 7 1 3 and 8 8 1 8 ka the currently active rock glacier started to develop before 3 7 0 8 ka and can be associated to the lobben oscillation four of the five rock avalanches dated in val viola cluster within the early holocene in correspondence of an atmospheric warming phase by contrast the timing of the main val viola rock avalanche 7 7 0 3 ka during the holocene thermal optimum suggests a possible causal linkage to permafrost degradation overall schmidt hammer proved to be an effective inexpensive and versatile tool for improving the spatial resolution of val viola post lgm landscape history starting from existing numerical age constrains

geology and radiometric 14c 36cl and th u dating of the fernpass rockslide tyrol austria abstract one of the largest mass movements in the alps the fossil fernpass rockslide in the northern calcareous alps tyrol austria was dated absolutely for the first time three independent radiometric dating methods were applied to geologically individual sample sites and enabled a cross checking of the results close to the scarp front rockslide dammed torrent deposits indicate a 14c minimum age of at least 3380 3080 cal yrs bp the chronostratigraphic base of this backwater sequence has not been dated yet but is assumed to date somewhat older into the middle holocene however this coincides with two cosmogenic radionuclide 36cl ages of sliding planes at the steep and rugged scarp exposure data thus obtained are 3400 900 and 4800 1200 yrs respectively with an arithmetic mean of 4100 1300 yrs additional age data were acquired from post depositional calcareous cements which locally lithified the rockslide debris these meteoric cements contain remarkably high uranium total contents and yielded a 230th 234u minimum age of about 4150 100 yrs for the accumulation of the rockslide deposits all dating data agree well and indicate that the fernpass rockslide is of subboreal age thus the intensively structured present morphology characterised by the well known cone shaped toma hills and several lakes in the depressions is indicative of primary rockslide morphology and clearly not shaped by late glacial ice as assumed formerly

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

slope instability in relation to glacial debuttressing in alpine areas upper durance catchment southeastern france evidence from field data and 10be cosmic ray exposure ages the upper durance catchment is an area prone to rock slope failures such failures reflect the combination of high relief litho structural controls and paraglacial stress release the aim of this study is to determine the role of deglacial unloading and resulting paraglacial stress release in conditioning or triggering slope failure former dimensions of the durance glacier are reconstructed then combined with digital elevation model data in a raster geographic information system to quantify the spatial pattern of stresses associated with glacial loading at the last glacial maximum preliminary calculations suggest that major rock falls and rock avalanches are associated with areas subject to the highest decompression stresses focus on two case studies allows the consequences of paraglacial stress release on slope instability to be evaluated description of slope failure runout deposits allows reconstruction of the nature of slope failure surface exposure dates based on concentration of cosmogenic 10be allows the timing of both deglaciation and that of post glacial rock slope failures to be established it is shown that rock slope failures are concentrated on lower valley side slopes within the area occupied by ice at the last glacial maximum and that their locations coincide with zones of inferred high glacial loading stress consistent with interpretation of both bedrock disruption and large scale rock slope failures as paraglacial phenomena induced by stress release following deglaciation timing of initial rock avalanche runout deposition at one site is consistent with this conclusion though later instability episodes at the same site may have occurred independent of the influence of paraglacial stress release

location of seismic signals associated with microearthquakes and rockfalls on the sechilienne landslide french alps the sechilienne rockslide in the french alps has recently been instrumented with three seismic arrays this network has recorded numerous rockfalls and local microearthquakes because the media is highly fractured it is difficult to identify and pick first arrivals beam forming methods were therefore used to locate these events the method has been adapted to take into account the heterogeneity of seismic wave velocities the location accuracy has been estimated to be about 50 m for epicenters by applying the method to calibration shots depth is less constrained due to uncertainties on the velocity model and due to the seismic network geometry this method of location has then been applied to rockfalls and microearthquakes most rockfalls initiate in the most active part of the rockslide called les ruines the others are located on a recent eroded area aside from les ruines the network also allows the estimation of the rockfall trajectory and propagation speed finally 55 microearthquakes have been located within two zones microearthquakes are located within the first 250 m below the surface most microearthquakes are located in les ruines the most active part of the rockslide where the velocity has increased from 0 5 m yr in 1996 to 1 4 m yr in 2008 these events are located close to three faults that delimit a mass of about 3 6 million m3 other events are located close to the summital scarp in a zone moving at a few centimeters per year the western part of the rockslide which moves more slowly did not produce any event large enough to be detected simultaneously by all stations this seismic monitoring suggests that only a very small fraction of the deformation is released through seismic events

aster capability in mapping of mineral resources of arid region a review on mapping of mineral resources of the sultanate of oman abstract advanced space borne thermal emission and reflection radiometer aster has exclusive capability to map minerals and ore deposits and able to discriminate rock types useful for geological applications especially the improved spectral and spatial resolutions of spectral bands of the sensor are well utilized by the exploration geologists working on arid region where the surface deposits are directly exposed to the sensor without disturbances of the vegetation several fruitful research studies have been carried out to map mineral resources in arid region with inaccessible rugged mountains and deserts area where it is difficult to do conventional geological mapping these were demonstrated and documented in the scientific publications using the aster spectral bands and image processing methods this study reviews scientific literatures published on mapping of the economic mineral resources of the sultanate of oman using aster and simples image processing methods

giant landslides topography and erosion abstract distributions of slope angles in tectonically active mountain belts point to the development of threshold conditions where hillslopes attain a critical inclination or height at which they fail readily because of limitations in material strength it has been proposed that hillslopes adjust to rapid uplift and bedrock incision through an increase in the rate of relief limiting landsliding rather than gradual slope steepening here we test this concept by investigating the relationship between mean local relief h which we take to be a proxy of long term erosion rates e and the occurrence of over 300 of the largest v 10 8 m 3 terrestrial landslides on earth we find that nearly two thirds of these giant landslides have occurred in the steepest 5 of the earth s land surface where relief is close to its proposed upper strength limit they are primarily located in deeply incised valleys along fault bounded fringes of active mountain belts and in volcanic arcs this distribution coincides with areas of high long term erosion rates 4 mm yr 1 confirming that giant landslides contribute to rapid denudation of mountains most of the eroded volume is concentrated in the smallest but steepest parts of mountain belts and volcanic arcs first order estimates of minimum erosion rates accomplished by the largest landslides are 0 01 mm yr 1 these rates are between 1 and 10 of the late pleistocene to holocene mean erosion rates in a given area importantly the landslide erosion rates show a nonlinear increase with mean local relief suggesting that the contribution of giant landslides in total and per event increases significantly with increasing overall erosion rates however giant landslides also occur in areas of lower than average relief h 300 700 m irrespective of whether threshold hillslopes have developed or not factors contributing to these failures include soft rocks extensive low angle discontinuities high rates of fluvial bedrock incision and tectonically driven deformation and slope loading

the failure mechanism of a late glacial sturzstrom in the subalpine molasse leckner valley vorarlberg austria a number of prehistoric landslides and rock avalanches occurred in the folded and faulted section of the molasse zone in vorarlberg austria some developed into a sturzstrom defined as a rapidly moving fluidised mass movement of large volumes of rock derived from the disintegration of a falling rock mass that spread under the influence of gravity their impact on the landscape usually is related to obstruction of rivers and valleys in this paper we analyse the geomorphology and the failure mechanism of a relative small sturzstrom the failure mechanism can be described as a buckling failure the morphological situation indicates that failure took place after local deglaciation by the end of the upper wurm the period of failure coincides with glacial and ice marginal remnants which developed between 15 000 and 14 600 bp the lithological sequence and rock structure as well as the impact of the processes related to the former glacial environment were major causal conditions the rock sequence consists of conglomerates sandstone layers and marls next to glacial scouring which increased the inclination of the valley slopes the effect of late glacial unloading and postglacial processes such as weathering and fluvial erosion subsequently weakened the mass rock fabric until failure occurred discontinuity orientation measurements geostructural and geomechanical conditions and the former hydrological and geomorphological conditions support bucklings failure in fact three hinge buckling may have occurred the frontal section of the sturzstrom consists mainly of large conglomerate blocks averaging 1 5 m3 in volume although megablocks reaching of up to 4000 m3 are present as well the volume of the entire sturzstrom equals approximately 10 107 m3 present activity is only restricted to minor rock falls derived from the conglomerates and mudflows originating from the marl layers

velocity variations and water content estimated from multi offset ground penetrating radar the common midpoint cmp processing technique has been shown to be effective in improving the results of ground penetrating radar gpr profiling when radar data are collected with the cmp multioffset geometry stacking increases the signal to noise ratio of subsurface radar reflections and results in an improved subsurface image an important aspect of cmp processing is normal moveout velocity analysis our objectives are to show the effect of multiple velocity analyses on the stacked radar image and particularly to demonstrate that this velocity information can also be used to determine subsurface water content most gpr surveys are very limited in spatial extent and assume that within the survey range radar velocity structure in the shallow subsurface can be adequately approximated by a single velocity function in data processing in this study we show that variation in radar velocity can be quite significant and that the stacked profile improves as the number of velocity analysis locations is increased interval velocities can be calculated from the normal moveout velocities derived in the cmp velocity analysis with some reasonable assumptions about subsurface conditions necessary for radar propagation interval velocity can be converted to an estimate of volumetric water content therefore by collecting gpr data in the multioffset cmp geometry not only is the radar profile improved but it also allows for an interpretation of subsurface variation in water content we show the application of these techniques to multioffset gpr data from the chalk river test area operated by atomic energy of canada limited

10be exposure ages of a rock avalanche and a late glacial moraine in alta valtellina italian alps abstract a rock avalanche deposit was investigated in order to understand the chronological evolution of geological hazards and to evaluate the interaction of the triggering geodynamic processes in the valley val viola italian alps the deposit is situated west of the alpe dosde in a permafrost area with deep seated gravitational deformations dsgd along a tectonic line based on its geomorphologic context the rock avalanche was first interpreted as a result of slope stress release without exact timing this hypothesis was tested by measuring the 10 be exposure date of quartz from one boulder from the rock avalanche the age of 7430 460 years places the event in the early holocene the timing of the last deglaciation was constrained using the inner late glacial moraine of a moraine doublet in the valley alpe dosde situated at an altitude between 2140 and 2120 m a s l west of the rock avalanche the 10 be concentrations of quartz yield minimum exposure ages of 11 480 670 and 10 850 820 years different proposals for potential triggering factors of the rock avalanche include a melting of the local valley glacier and slope stress release in the val viola likely to play a minor role as trigger because of the time delay between the deglaciation and the rock avalanche event more likely are b enhanced crustal seismicity induced by post glacial regional isostatic glacial rebound coupled with tectonic stress or and c climate conditions with higher temperatures around 7430 460 years resulting in an upwards movement of the permafrost limit and destabilization of the rock walls

high resolution water content estimation from surface based ground penetrating radar reflection data by impedance inversion 1 mapping hydrological parameter distributions in high resolution is essential to understand and simulate groundwater flow and contaminant transport of particular interest is surface based ground penetrating radar gpr reflection imaging in electrically resistive sediments because of the expected close link between the subsurface water content and the dielectric permittivity which controls gpr wave velocity and reflectivity conventional tools like common midpoint cmp velocity analysis provide physical parameter models of limited resolution only we present a novel reflection amplitude inversion workflow for surface based gpr data capable of resolving the subsurface dielectric permittivity and related water content distribution with markedly improved resolution our scheme is an adaptation of a seismic reflection impedance inversion scheme to surface based gpr data key is relative amplitude preserving data preconditioning including gpr deconvolution which results in traces with the source wavelet distortions and propagation effects largely removed the subsequent inversion for the underlying dielectric permittivity and water content structure is constrained by in situ dielectric permittivity data obtained by direct push logging after demonstrating the potential of our novel scheme on a realistic synthetic data set we apply it to two 2 d 100 mhz gpr profiles acquired over a shallow sedimentary aquifer resulting in water content images of the shallow 3 7 m depth saturated zone having decimeter resolution

surface exposure dating of the flims landslide graubunden switzerland abstract sixteen boulder and bedrock surfaces related to the flims landslide volume 8 12 km3 were dated with 36cl and 10be exposure ages range from 4900 250 yr to 15 440 1480 yr including corrections made due to snow cover and karst erosion ages of 11 410 590 yr and 13 340 1090 yr were obtained on bedrock surfaces outside of the landslide zone these are minima for deglaciation of segnes valley and provide constraints on possible amounts of inherited nuclides based on seven boulder ages which range from 8200 260 to 9520 990 yr a mean of 8900 700 years is calculated for the flims landslide we exclude three outliers one significantly older and two significantly younger than the others and the ages from the cassons bedrock site from the mean calculation the latter is excluded as shielding due to snow and vegetation cover is difficult to constrain there the oldest boulder on the landslide yielded an age 15440 1480 yr more than 5000 years older than any other boulder age suggesting that it included the surface of the pre slide bedrock the exposure ages are consistent with a single failure event the erratics and patches of till lying on the landslide debris must have been carried piggy back on top of the landslide rather than having been deposited by the late pleistocene vorderrhein glacier the flims rockslide is about the same age as the kofels 9800 yr and kandertal 9600 yr rockslides all three occurred during the marked transition to warmer wetter conditions during the early holocene

joint application of surface electrical resistivity and gpr measurements for groundwater exploration on the island of spiekeroog northern germany geophysical surveys have been carried out on the east frisian island of spiekeroog at the german north sea coast in 1996 so called freshwater lenses lying on top of saltwater saturated layers because of their lower density provide most of the freshwater supply on the frisian islands the major goal of the present study is to show the possibilities of a joint application of surface electrical resistivity soundings and ground penetrating radar gpr for the hydrogeological investigation of the island it is shown that a comprehensive interpretation of large scale gpr profiling data in a sandy aquifer provides valuable hydrogeological information especially if there is not any other information available such as from boreholes or groundwater measuring points applying the techniques of surface electrical resistivity and ground penetrating radar jointly we were able to construct a groundwater contour map for the entire island of spiekeroog in addition we were able to delineate hydrogeologically important changes in grain size and stratigraphical features and to indicate temporal changes of the spatial extent of the freshwater reservoir in comparison to earlier less complete investigations finally we located an area previously unknown in the eastern part of the island where precipitation appears to be developing a substantial new freshwater lens

the recent fault scarps of the western alps france tectonic surface ruptures or gravitational sackung scarps a combined mapping geomorphic levelling and 10be dating approach abstract in the western alps some recent scarps were previously interpreted as surface ruptures of tectonic reverse and normal faults that agree with microseismicity and gps measurements our analysis shows that in fact there are hundreds of recent scarps up to 30 m high and 2 1 km long with only pure normal motions they share the same characteristics as typical sackung scarps the scarps are mainly uphill facing parallel to the ridge crests and the contour lines they are relatively short less than 2 1 km with respect to tectonic fault ruptures and organized in swarms they cut screes and relict rock glaciers with a slow commonly 1 mm year average slip rate in the aiguilles grives massif these sackung scarps clearly express the gravitational toppling of sub vertical bedding planes in hard rocks in contrast the belledonne outer crystalline massif exhibits scarps that stem from the gravitational reactivation of conjugate tectonic faults the recent faults extend to about 1600 m beneath the rognier ridge crest but are always above the valley floor the main scarp swarm is 9 2 km long and constitutes the largest sackung ever described in the western alps 10 be dating of a scarp and offset surfaces shows that 4 m slip may have occurred rapidly in less than 3800 years sometimes between the end of the glaciation and 8800 1900 years ago this dating together with the location of some faults far from the deep glacial valleys suggests that sagging might have been triggered by strong earthquakes during a post glacial period of probably enhanced seismicity the belledonne and synclinal median faults just beneath the rognier sackung could have been the sources of this seismicity

split step fourier migration the split step fourier method is developed and applied to migrating stacked seismic data in two and three dimensions this migration method which is implemented in both the frequency wavenumber and frequency space domains takes into account laterally varying velocity by defining a reference slowness reciprocal of velocity as the mean slowness in the migration interval and a perturbation term that is spatially varying the mean slowness defines a reference vertical wavenumber which is used in the frequency wavenumber domain to downward continue the data across a depth interval as in constant velocity phase shift migration the perturbation term is used to define a source contribution that is taken into account by the application of a second phase shift in the frequency space domain since the method does not include the effects of second and higher order spatial derivatives of the slowness field the method theoretically is accurate only when there are no rapid lateral slowness variations combined wi

mapping of neoproterozoic source rocks of the huqf supergroup in the sultanate of oman using remote sensing abstract in recent years the neoproterozoic huqf supergroup formations of the oman salt basins have been the target for oil exploration the present study maps the surficial exposure of the huqf supergroup in and around khufai dome of the huqf area in the sultanate of oman using low cost multi spectral remotely sensed satellite data and image processing methods such as decorrelation stretching principal component analysis pca and spectral angle mapper sam as alternative to expensive and time consuming tools which have the capability and potential to be used by geoscientists for oil exploration in this research the study of advanced spaceborne thermal emission and reflection radiometer aster spectral bands 8 3 and 1 by decorrelation stretching well discriminated the masirah bay the khufai the shuram and the buah formations of the nafun group the source rocks of huqf supergroup with the quaternary deposits the analysis of visible and near infrared shortwave infrared spectral bands of aster by pca clearly showed the occurrence and spatial distribution of such formations in the rgb principal component images r pc1 g pc2 b pc3 the spatial distributions of such formations are assessed by confusion matrix after using maximum likelihood ml spectral angle mapper sam and spectral information divergence sid algorithms the matrix of ml algorithm has provided the best overall accuracy of 92 93 and kappa coefficient of 0 92 the minerals of the formations were detected by sam further the detection of such mineral groups was confirmed through the aster thermal infrared tir spectral indices image developed using the carbonate index ci quartz index qi and mafic index mi all results of image analyses are evaluated in the field and laboratory studies the study also evaluates the satellite data and image processing methods for the formations of jabal akhdar the equivalent formations of the khufai dome to show the sensor capability and the use of the image processing methods to study the source rocks the results of the study provided similar discriminations comparable to the khufai dome therefore the data and the techniques are recommended to the exploration geologists for use in similar regions of the world

rapid holocene deglaciation of the labrador sector of the laurentide ice sheet abstract retreat of the laurentide ice sheet lis following the last glacial maximum 21 000 yr bp affected regional to global climate and accounted for the largest proportion of sea level rise although the late pleistocene lis retreat chronology is relatively well constrained its holocene chronology remains poorly dated limiting our understanding of its role in holocene climate change and sea level rise here new 10be cosmogenic exposure ages on glacially deposited boulders are used to date the final disappearance of the labrador sector of the lis ls lis these data suggest that following the deglaciation of the southeastern hudson bay coastline at 8 0 0 2 cal ka bp the southwestern margin of the ls lis rapidly retreated 600 km in 140 yr and most likely in 600 yr at a rate of 900 m yr 1 with final deglaciation by 6 8 0 2 10be ka the disappearance of the ls lis 6 8 10be ka and attendant reduction in freshwater runoff may have induced the formation of labrador deep seawater while the loss

a late holocene deep seated landslide in the northern french pyrenees abstract a very large deep seated landslide dsl in the northern pyrenees with over 1 4 10 9 m 3 was mapped and dated based on sedimentation rates and 10 be terrestrial cosmogenic radionuclide surface exposure cre dating our analysis on the landslide reveals the role of inherited structures in the landslide process and highlighted typical gravitational morpho structures and a small lake trapped at the toe of the landslide head scarp the rate of lake sedimentation 0 86 0 57 mm yr 1 also provided us with the approximate age of the landslide 1106 540 yr the cre dating result highlights two main slope destabilization phases then we discussed the history of dsl activity and its controlling factors information related to historic markers and the absence of particular climate markers and changes during the medieval dark ages point to a single event in ad 1380 due to a major seismic event lavedan earthquake

ice ablation as evidence of climate change in the alps over the 20th century 1 over fifty years of cumulative annual mass balance data for several glaciers in the alps shows similar fluctuations which seem to provide evidence of a common climatic signal separate winter and summer mass balance measurements from the claridenfirn glacier in switzerland since 1914 and the sarennes glacier france since 1949 show that 1 the annual mass balance is primarily driven by the summer mass balance term and 2 melting rate variations with time are very similar for these two glaciers located 290 km apart the increase in the ablation rate of 0 5 cm w e day 1 between the two periods 1954 1981 and 1982 2002 over these two glaciers corresponds to a 20 wm 2 rise in the energy flux at the glacier surface these results suggest that a common summer melting rate change may have affected the alps as a whole detailed observations on the sarennes glacier show that the origin of this strong increase in summer ablation since 1982 is not only a rise in the summer melting rate but also an increase in the ablation period during the months of september and october

recent climatic change and catastrophic geomorphic processes in mountain environments climatic warming during the last 100 150 years has resulted in a significant glacier ice loss from mountainous areas of the world certain natural processes which pose hazards to people and development in these areas have accelerated as a result of this recent deglaciation these include glacier avalanches landslides and slope instability caused by glacier debuttressing and outburst floods from moraine and glacier dammed lakes in addition changes in sediment and water supply induced by climatic warming and glacier retreat have altered channel and floodplain patterns of rivers draining high mountain ranges the perturbation of natural processes operating in mountain environments caused by recent climatic warming ranges from tens of decades for moraine dam failures to hundreds of years or more for landslides the recognition that climatic change as modest as that of the last century can perturb natural alpine processes has important implications for hazard assessment and future development in mountains even so these effects are probably at least an order of magnitude smaller than those associated with late pleistocene deglaciation ca 15 000 to 10 000 years ago

visualization of active faults using geometric attributes of 3d gpr data an example from the alpine fault zone new zealand three dimensional ground penetrating radar gpr data are routinely acquired for diverse geologic hydrogeologic archeological and civil engineering purposes interpretations of these dataareinvariablybasedonsubjectiveanalysesofreflectionpatterns such analyses are heavily dependent on interpreter expertiseandexperience usingdataacquiredacrossgravelunitsoverlyingthealpinefaultzoneinnewzealand wedemonstratethe utilityofvariousgeometricattributesinreducingthesubjectivity of3dgprdataanalysis weuseacoherence basedtechniqueto compute the coherency azimuth and dip attributes and a graylevel co occurrence matrixglcmmethod to compute the texture basedenergy entropy homogeneity andcontrastattributes a selection of the gpr attribute volumes allows us to highlight key aspects of the fault zone and observe important features not apparent in the standard images this selection also provides information that improves our understanding of gravel deposition andtectonicstructuresatthestudysite anewdepositional structuralmodellargelybasedontheresultsofouranalysisofgprattributes includes four distinct gravel units deposited in three phases and a well defined fault trace this fault trace coincides with a zone of stratal disruption and shearing bound on one side by upward tilted to synclinally folded stratified gravels and on the other side by moderately dipping stratified alluvial fan gravelsthatcouldhavebeenaffectedbylateralfaultdrag whenused in tandem the coherence and texture based attribute volumes can significantly improve the efficiency and quality of 3d gpr interpretation especially for complex data collected across activefaultzones

late quaternary depositional history of the reuss delta switzerland constraints from high resolution seismic reflection and georadar surveys glacial erosion has caused overdeepening of many alpine valleys after retreat of the ice they were filled with heterogeneous deposits of glacial lacustrine and fluvial sediments a typical example of such a valley segment and its infill is the reuss delta on the southern shore of lake lucerne in switzerland to obtain a detailed three dimensional image of this valley segment the eth institute of geophysics has acquired several two dimensional high resolution seismic and georadar profiles and conducted a three dimensional georadar survey interpretations of these geophysical data were constrained by a geological core extracted from a borehole 300 m deep near the investigation site the seismic profiles imaged ca 600 m of sediment infill above bedrock based on their reflection characteristics five different deposition units were distinguished these units were interpreted as a succession of clay silt at the base followed by different sand units with variable but generally increasing amounts of gravel this succession represented a prograding delta that filled the southern part of lake lucerne the latest fluvial development of the region is best represented by the georadar data in particular the three dimensional georadar data set provides a detailed view of an ancient braided river channel copyright 2002 john wiley sons ltd

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

integrating surface georadar and crosshole radar tomography a validation experiment in braided stream deposits we have used a combination of surface ground penetrating radar gpr profiling crosshole radar tomography and natural gamma ray logging to characterize a gravelly braided stream deposit in a gravel pit we conducted a survey using 300 mhz surface gpr 250 mhz crosshole radar and densely sampled gamma ray logging at single borehole locations after excavation we validated the geophysical results by comparison with the sedimentological and hydrogeological information obtained from the corresponding outcrop wall we found the visual lithofacies boundaries agreed very well with the images provided by applied geophysical techniques our results illustrate how gpr reflector images are improved using tomographic velocity information in addition the structural interpretation of tomographic velocity fields is guided by the gpr reflector images in combination with natural gamma ray logging results groundwater flow and transport modeling was also performed on different subsurface models the hydrogeological r

ground penetrating radar for high resolution mapping of soil and rock stratigraphy ground penetrating radar is a technique which offers a new way of viewing shallow soil and rock conditions the need to better understanding overburden conditions for activities such as geochemical sampling geotechnical investigations and placer exploration as well as the factors controlling groundwater flow has generated an increasing demand for techniques which can image the subsurface with higher resolution than previously possible the areas of application for ground penetrating radar are diverse the method has been used successfully to map ice thickness water depth in lakes bedrock depth soil stratigraphy and water table depth it is also used to delineate rock fabric detect voids and identify karst features the effective application of the radar for the high resolution definition of soil stratigraphy and fractures in bedrock is highlighted the basic principles and practices involved in acquiring high quality radar data in the field are illustrated by selected case histories one example demonstrates how radar has been used to map the bedrock and delineate soil horizons to a depth of more than 20 m two case histories show how radar has been used to map fractures and changes of rock type to 40 m range from inside a mine another case history demonstrates how radar has also been used to detect and map the extent of groundwater contamination the corroboration of the radar results by borehole investigations demonstrates the power and utility of the high resolution radar method as an aid for interpolation and extrapolation of the information obtained with conventional coring programmes with the advent of new instrumentation and field procedures the routine application of the radar method is becoming economically viable and the method will see expanded use in the future

applying reflection tomography in the postmigration domain to multifold ground penetrating radar data acquisition and processing of multifold ground penetrating radar gpr data enable detailed measurements of lateral velocity variability the velocities constrain interpretation of subsurface materials and lead to significant improvement in image accuracy when coupled with prestack depth migration psdm reflection tomography in the postmigration domain was introduced in the early 1990s for velocity estimation in seismic reflection this robust accurate method is directly applicable in multifold gpr imaging at a contaminated waste facility within the u s department of energy s hanford site in washington the method is used to identify significant lateral and vertical velocity heterogeneity associated with infilled waste pits using both the psdm images and velocity models in interpretation a paleochannel system that underlies the site and likely forms contaminant migration pathways is identified

10be dating reveals pronounced mid to late holocene activity of deep seated landslides in the highest part of the czech flysch carpathians abstract although the highest part of the czech outer western carpathians lacks significant recent landslide activity the vast area 20 of their territory is occupied by relict deep seated landslides and deep seated gravitational slope deformations dating these deformations might help to determine degrees of present day landslide hazard in that area based on the 10be exposure dating of eight rocky scarps and walls of ridge top trenches we estimated the minimal ages of the deep seated landslides dsls and one deep seated gravitational slope deformation dsgsd in the satina river basin in the moravskoslezske beskydy mts the obtained ages 9 7 2 9 ka suggest holocene slope instability in the area with a pronounced cluster of ages spanning from 6 0 to 2 9 ka except for one dsl the ages reveal rather episodic activity of gravitational movements mid to early late holocene activity of large landslides in the study area corresponds to the ages of several previously dated landslides both in an adjacent region as well as within the central european context with respect to the historical quiescence of the dsls and dsgsds in the area and because the slopes have not been destabilized even during the most extreme hydrometeorological events within the last few decades we infer that the hydrometeorological thresholds necessary for their activation are seldom exceeded in this area therefore the highest parts of the carpathians built by rigid thick bedded lithology reveal a rather lower frequency of events in comparison with adjacent parts formed by claystone dominated flysch where several large dsls originated in the last few decades as a consequence of heavy rainfalls

interpretation of drill core and georadar data of coarse gravel deposits abstract pollution in the shallow subsurface has led to an increasing need of understanding how to quantitatively characterize both the heterogeneity of gravel aquifers and the influence of heterogeneity on groundwater flow and solute transport models play an important role in decision making processes especially in the context of better characterizing and in forecasting the behavior of a given geological system the objective of the present paper is the derivation of a gradual lithofacies based interpretation of outcrop drill core and ground penetrating radar gpr or georadar data of different quality the presented method allows a probability estimation of drill core layer descriptions and radarfacies types representing defined sedimentary structure types the method includes a determination of initial structure type probabilities for grain size categories and combinations thereof described in drill core layer descriptions as well as a subsequent differentiation of these structure type probabilities in an iterative process considering additional information like main constituent quantity fraction and sorting of single grain size categories color chemical precipitation layer thickness and adjacent layer the radarfacies types are calibrated with drill cores located in the vicinity of georadar sections the calibration process consists of the assignment of the calculated structure type probabilities from the drill core layer descriptions to the corresponding radarfacies types considering the proportion in thickness between drill core layers and georadar structures the structure type probabilities can be given for points along boreholes and a grid with arbitrary mesh size along georadar sections the method is applied to field examples from the rhine wiese aquifer near basel in switzerland the resulting structure type probabilities can be used for conditioning stochastic simulations of geological models however the conditioned stochastic simulation of the rhine wiese aquifer is the topic of another paper the results show the importance of a detailed sedimentological analysis of outcrops and drill cores as well as its significance on the distinction of sedimentary structure types

relating lithofacies to hydrofacies outcrop based hydrogeological characterisation of quaternary gravel deposits abstract a considerable part of today s drinking water supplies in europe and north america rely on clean groundwater from gravelly valley aquifers of quaternary age the sedimentary architecture the distribution of lithofacies and of architectural elements in such heterogeneous deposits are of fundamental importance for the analysis of groundwater flow and contaminant transport as the aquifers are not directly accessible for observation representative outcrop analogues were used to study the sedimentology on a local scale conventional sedimentological classification schemes were adapted for the purpose of hydrogeological evaluations measurements of hydraulic properties were then used to define a set of 5 hydrofacies from 23 possible sediment lithofacies a digital photographic mapping procedure was developed to allow fast data acquisition in the field the sedimentologically interpreted outcrops were stored in a gis style database and thus allow the output for further sedimentological or hydrogeological analysis

cosmogenic radionuclide dating of glacial landforms in the lahul himalaya northern india defining the timing of late quaternary glaciation the timing of glaciation in the lahul himalaya of northern india was ascertained using the concentrations of cosmogenic 10be and 26al from boulders on moraines and drumlins and from glacially polished bedrock surfaces five glacial stages were identified sonapani i and ii kulti batal and chandra of these cosmogenic exposure ages were obtained on samples representative of the batal and kulti glacial cycles stratigraphical relationships indicate that the sonapani i and ii are younger no age was obtained for the chandra glacial advance batal glacial stage deposits are found throughout the valley indicating the presence of an extensive valley glacial system during the kulti stage glaciers advanced ca 10 km beyond their current positions moraines produced during the batal stage ca 12 15 5 ka are coeval with the northern hemisphere late glacial interstadial bolling allerod deglaciation of the batal glacial stage was completed by ca 12 ka and was followed by the kulti glacial stage during the early holocene at ca 10 11 4 ka on millennial time scales glacier oscillations in the lahul himalaya apparently reflect periods of positive mass balance coincident with times of increased insolation during these periods the south asian summer monsoon strengthened and or extended its influence further north and west thereby enhancing high altitude summer snowfall copyright 2001 john wiley sons ltd

holocene climate variability as reflected by mid european lake level fluctuations and its probable impact on prehistoric human settlements abstract a data set of 180 radiocarbon tree ring and archaeological dates obtained from sediment sequences of 26 lakes in the jura mountains the northern french pre alps and the swiss plateau was used to construct a holocene mid european lake level record the dates do not indicate a random distribution over the holocene but form clusters suggesting an alternation of lower and higher climatically driven lake level phases they provide evidence of a rather unstable holocene climate punctuated by 15 phases of higher lake level 11 250 11 050 10 300 10 000 9550 9150 8300 8050 7550 7250 6350 5900 5650 5200 4850 4800 4150 3950 3500 3100 2750 2350 1800 1700 1300 1100 750 650 cal bp and after 1394 ad a comparison of this mid european lake level record with the gisp2 polar circulation index pci record the north atlantic ice rafting debris ird events and the 14 c record suggests teleconnections in a complex cryosphere ocean atmosphere system correlations between the gisp2 pci the mid european lake level the north atlantic ird and the residual 14 c records suggest that changes in the solar activity played a major role in holocene climate oscillations over the north atlantic area

combining amphibious geomorphology with subsurface geophysical and geological data a neotectonic study at the front of the alps bernese alps switzerland abstract in the vicinity of lake thun at the front of the bernese alps switzerland we performed a multidisciplinary neotectonic study combining onshore and offshore geological data and geophysical measurements in order to identify potentially active fault structures paleoseismic reconstructions on the northern margin of the alps have documented several strong earthquakes with moment magnitudes 6 during the late quaternary which have long recurrence intervals of 1 000 to 2 000 years such earthquakes are expected to produce surface ruptures in this light we investigated the study area located near lake thun primarily for on fault evidence to date still a shortcoming in switzerland we detected several features indicating potential fault activity such as aligned subaquatic morphological depressions offset horizons observed in reflection seismic profiles of lake sediments and in ground penetrating radar images all delineating a fault trace observations of fluvial deposits in a nearby gravel pit in the prolongation of the inferred structure supports these findings a narrow zone with rotated long axes of pebbles inclining at 60 is clearly distinguishable and crosscuts the original bedding with predominantly horizontal orientation of pebble axes this zone further shows an apparent 1 1 m offset of oxidized horizons and is therefore considered as a potential fault plane in a normal faulting regime a dated radiocarbon age of 11 000 years bp of the gravel deposits hence suggests a younger fault activity during the holocene the einigen fault zone efz proposed on the basis of these observations is considered as a complex fault system with a combination of dextral strike slip and normal faulting as suggested by gpr images observations in the gravel pit and radar data independently show that it includes at least two fault strands however while five earthquakes with epicentral intensities i 0 vi and numerous smaller seismic events are known within less than 30 km epicentral distance to lake thun over the past 400 years none of these seem to coincide with the location of the efz

acquisition and processing strategies for 3d georadar surveying a region characterized by rugged topography efficiently performing 3d ground penetrating radar gpr or georadar surveys across rugged terrain and then processing the resultant data are challenging tasks conventional approaches using unconnected gpr and topographic surveying equipment are excessively time consuming for such environments and special migration schemes may be required to produce meaningful images we have collected gpr data across an unstable craggy mountain slope in the swiss alps using a novel acquisition system that records gpr and coincident coordinate information simultaneously undulating topography dips of 8 to 16 and boulders with diameters up to about 2 m complicated the field campaign after standard processing the data were found to be plagued by time shifts associated with minor coordinate inaccuracies uneven antenna ground coupling and numerous small gaps in data coverage these problems were resolved by passing the data sequentially through an adaptive f xy deconvolution routine and f kx and f ky filters this filtering also reduced incoherent noise finally the data were migrated using a 3d algorithm that accounted for the undulating topography the nonmigrated and migrated images contained gently and moderately dipping reflections from lithological boundaries and actively opening fracture zones a suite of prominent diffraction patterns was generated at a steeply dipping fracture zone that projected to the surface through this case history we introduce a general strategy for 3d gpr studies of topographically rugged land

lithologic mapping in the mountain pass california area using advanced spaceborne thermal emission and reflection radiometer aster data abstract evaluation of an advanced spaceborne thermal emission and reflection radiometer aster image of the mountain pass california area indicates that several important lithologic groups can be mapped in areas with good exposure by using spectral matching techniques the three visible and six near infrared bands which have 15 m and 30 m resolution respectively were calibrated by using in situ measurements of spectral reflectance calcitic rocks were distinguished from dolomitic rocks by using matched filter processing in which image spectra were used as references for selected spectral categories skarn deposits and associated bright coarse marble were mapped in contact metamorphic zones related to intrusion of mesozoic and tertiary granodioritic rocks fe muscovite which is common in these intrusive rocks was distinguished from al muscovite present in granitic gneisses and mesozoic granite quartzose rocks were readily discriminated and carbonate rocks were mapped as a single broad unit through analysis of the 90 m resolution five band surface emissivity data which is produced as a standard product at the eros data center three additional classes resulting from spectral angle mapper processing ranged from 1 a broad granitic rock class 2 to predominately granodioritic rocks and 3 a more mafic class consisting mainly of mafic gneiss amphibolite and variable mixtures of carbonate rocks and silicate rocks

modeling permafrost extension in a rock slope since the last glacial maximum application to the large sechilienne landslide french alps article i nfo recent dating performed on large landslides in the alps has revealed that the initiation of instability did not immediately follow deglaciation but occurred several thousand years after ice down wastage in the valleys this result indicates that debuttressing is not the immediate cause of landslide initiation the period of slope destabilization appears to coincide with the wetter and warmer holocene climatic optimum indicating a cli matic cause of landslide triggering although the role of seismic activity cannot be ruled out a phenomenon which may partly explain the delay between valley deglaciation and gravitational instability is the temporal persistence of thick permafrost layers developed in the alps since the last glacial maximum lgm this hy pothesis was tested through 2d thermal numerical modeling of the large sechilienne landslide romanche valley french alps using plausible input parameter values simulation results suggest that permafrost vanished in the sechilienne slope at 10 to 11 ka 3000 to 4000 years following the total ice down wastage of the romanche valley at 14 3 ka permafrost persistence could have contributed to the failure delay by tempo rally strengthening the slope numerical simulations also show that the permafrost depth expansion approxi mately fits the thickness of ground affected by gravitational destabilization as deduced from geophysical investigations these results further suggest that permafrost development associated with an ice segregation mechanism damaged the rock slope and influenced the resulting landslide geometry

exposure age chronology of the last glaciation in the eastern pyrenees abstract we present a chronology of ice recession in the eastern pyrenees based on in situ produced 10be data obtained from the tet paleoglacier complex the sampling strategy is based on the relative chronology provided by a detailed geomorphological map of glacial landforms results indicate that the last maximum ice advance occurred late i e during marine isotope stage 2 compared to the chronology currently established for the rest of the pyrenees despite debatable evidence for a glacial readvance during the oldest dryas stade ice cap melt out was rapid residual cirque glaciers having disappeared by the allerod interstade this is consistent both with north atlantic excursions established by the greenland ice cores and paleoenvironmental data for the region the rapid response of the east pyrenean ice cap to temperature variations is primarily linked to its small size compared to larger pyrenean ice fields to the dry mediterranean climate and to topography related nonlinearities in which a small vertical rise in equilibrium line altitude generates a large change in ice mass possible sources of age uncertainty are discussed in the context of sampling design for single nuclide 10be dating of landform sequences in formerly glaciated landscapes

long term dynamics of rockslides and damage propagation inferred from mechanical modeling 1 long term observations of large active rockslides show accelerating deformation over many thousands of years since the last deglaciation the effect of deglaciation on slope stability is however poorly understood due to 1 limited long term observations and 2 a complex interaction between glacier retreat and hydrogeological mechanical and morphological processes to assess the sensitivity of rockslide dynamics to these different processes a model of progressive damage through intact rock mass is developed in this study based on the finite element method this model uses time to failure laws based on rock laboratory creep experiments it is able to reproduce progressive damage localization along shear bands associated with strain rate acceleration as observed during tertiary creep the model reproduces the different phases of deformation associated with morphologies typical of large rockslides this model is thus suitable for simulating the dynamics of large rockslides and the transition from initiation to rapid sliding the sensitivity of rockslide kinematics and morphology to different mechanical properties is analyzed this analysis shows that the time evolution of the rockslide can be inferred with the knowledge of only one time parameter independent of the knowledge of the mechanical properties of the rock mass this parameter is here chosen as the time when the summit slope displacement has reached 10 m a parameter that can be estimated with cosmogenic dating the model is then used to study the effects of deglaciation on the valley flank stability and the formation of large rockslides this study shows that the deglaciation velocity can affect the morphology of the rockslide with the shear band of the rockslide emerging at higher elevation as the velocity decreases we also show that the response to the deglaciation can last several thousands of years after the glacier retreat

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

seismic monitoring of sechilienne rockslide french alps analysis of seismic signals and their correlation with rainfalls 1 in the french alps sechilienne rockslide is one of the natural phenomena that presents one of the highest levels of risk in terms of socioeconomical outcomes this rockslide has been active for a few decades and has been instrumented since 1985 the current very active volume of this rockslide is estimated to be up to 5 million m3 located on the border of a slowly moving mass reaching 50 100 million m3 the velocity of the most active zone reached 1 4 m yr in 2008 about twice the value of 2000 a seismic network was installed on this rockslide in may 2007 to supplement the monitoring system it has now recorded several thousand events mostly rockfalls but also hundreds of local and regional earthquakes which can be distinguished and classified from their signal characteristics rockfalls and microseismicity which occur in bursts of activity are found to be weakly but significantly correlated with rainfall rockfall occurrence increases linearly with precipitation with however strong fluctuations of the numbers of rockfalls per day for the same rainfall intensity no threshold was found for rainfall triggering with even 1 mm of rain being enough to trigger rockfalls rockfall activity starts almost immediately during a rainfall episode and lasts for several days after the rainfall rain also induces strong accelerations of the rockslide movement which also start quasi instantaneously and last for about a month

deep geophysical investigation of the large sechilienne landslide western alps france and calibration with geological data a geophysical imaging campaign including four 950 m electrical profiles and four 470 m long seismic profiles was performed on the large sechilienne landslide with the objective of constraining the depth and the volume of the affected zone compared to the undisturbed ground the moving area exhibits lower velocity and higher resistivity values comparison with existing geodetic geomorphic and geological data investigation gallery and borehole allowed showing that these geophysical parameter variations result from intense fracturing and the progressive development of air filled voids within the moving mass a maximum thickness of 150 m to 200 m was found in the most deconsolidated zones locally near vertical very low resistivity anomalies were evidenced related to cataclasis zones filled with clayey material applying the wyllie s experimental law rock mass porosity images were derived from seismic tomography profiles porosity between 30 and 4 was found from the top to the bottom of the deconsolidated zone explaining the deep water table considering a porosity threshold of 3 7 for the sound bedrock the total volume of the sechilienne landslide was estimated to about 60 10 106 m3 a more precise bracket than the previous estimations 20 106 to 100 106 m3

rock type leaves topographic signature in landslide dominated mountain ranges 1 the idea that hillslopes in active mountain belts are limited to a threshold inclination by the rate of landsliding has guided landscape evolution models for over a decade however widely applied topographic diagnostics of threshold hillslopes remain debated and unverified this study relates landslide occurrence to hillslope metrics of several active mountain ranges throughout new zealand which are formed in uniform greywacke and its schist derivative all these ranges share a distinctive peak in hillslope inclination despite order of magnitude variations in rates of rock uplift and precipitation landslide density and extent of quaternary glaciation comparison with landslide dominated terrain in different lithologies highlights this peak as diagnostic of rock type reflecting a conspicuous tendency in hillslope evolution to adjust to rock mass strength irrespective of the intensity of tectonic and climatic forcing this finding expands the model perspective that only undisturbed strength equilibrium slopes may adjust to their rock mass strength

interaction between tectonic and erosion processes on the morphogenesis of an alpine valley geological and geophysical investigations in the lower romanche valley belledonne massif western alps in the belledonne massif the steep paleozoic belledonne middle fault bmf separates micaschists displaying numerous landslides from amphibolites the massif is incised by the lower romanche river valley when crossing the bmf the valley widens into a lozenge shaped basin recently interpreted as an active pull apart type structure associated with a major n110 striking quaternary fault multidisciplinary investigations were carried out in the basin to check if this model has implications on the seismic and landslide hazard assessment this study demonstrated the existence of a n80 sinistral strike slip sechilienne fault zone sfz this fault zone is suspected to offset the bmf by 375 m across the basin geophysical experiments revealed that the bedrock depth increases strongly in the basin up to 350 m our study invalidates the active pull apart origin of the basin and suggests it results from quaternary glacial and fluvial erosion processes magnified by the intersection of two inherited structures the bmf and the sfz

in situ produced 10be measurements at great depths implications for production rates by fast muons in situ cosmogenic 10be values have been used to investigate a brazilian quartz vein from the surface to a depth of 15 m at depths greater than 1000 g cm2 deep enough for neutron induced reactions to be insignificant there is only a slight decrease in 10be concentration with increasing depth our results are consistent with deep production of 10be by a mechanism presumably induced by fast muons with an attenuation length of 5300 950 g cm2 and a contribution of 0 65 0 25 to the total surface production results are compared with values from the literature and implications of this re evaluation are discussed

transport modeling in heterogeneous aquifers 1 statistical description and numerical generation of gravel deposits transport of solutes in groundwater is decisively influenced by the heterogeneity of the aquifer the goal of the present work is the numerical generation of synthetic heterogeneous aquifer models based on a statistical description of heterogeneities in gravel aquifers large unweathered outcrops in several gravel pits in northeastern switzerland were investigated in this context on the basis of sedimentological observations it was possible to specify distinct sedimentary structures appearing as lenses or layers all structures have been identified in each of the investigated outcrops by inspecting and analyzing photographs of the outcrops it was possible to estimate the probability density functions pdf of the geometrical attributes of the sedimentary structures disturbed and undisturbed samples were taken from these structures to estimate the pdf of their hydraulic properties that is the hydraulic conductivity and the porosity the information obtained is used to generate distinct numerical realizations by unconditional stochastic simulation of synthetic aquifers having the same statistical properties with respect to hydraulic conductivity and porosity as the investigated deposits

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

the belledonne border fault identification of an active seismic strike slip fault in the western alps summary in the french western alps east of grenoble we identify the belledonne border fault as an active seismic fault this identification is based on the seismic monitoring of the grenoble area by the sismalp seismic network over the past 12 yr 1989 2000 we located a set of earthquakes with magnitudes ranging from 0 to 3 5 along a 50 km long alignment which runs in a n30 e direction on the western flank of the belledonne crystalline massif available focal solutions for these events are consistent with this direction n36 e strike slip fault with right lateral displacement these events along the belledonne border fault have a mean focal depth of 7 km in the crystalline basement with a probably very low slip rate the belledonne border fault has never been mapped at the surface where the otherwise heavily folded and faulted mesozoic cover makes this identification difficult historical seismicity also shows that over the past two and a half centuries a few events located mainly along the southern part of the belledonne border fault caused damage with the magnitude 4 9 1963 monteynard earthquake reaching intensity vii the most recent damaging event in the study area is the magnitude 3 5 1999 laffrey earthquake intensity v vi although its epicentre lies at the southern tip of the belledonne border fault there is clear evidence that aftershocks were activated by the left lateral slip of a n122 e striking fault the length of the belledonne border fault which could easily accommodate a magnitude 6 event as well as the proximity to the isere valley with its unlithified quaternary deposits up to 500 m thick known to generate marked site effects make the identification of the belledonne border fault an important step in the evaluation of seismic risk in the grenoble area besides the activity observed on the fault will now have to be taken into account in future geodynamic models of the western alps