geophysical analysis of transverse ridges and internal structure at lone peak rock glacier big sky montana usa rock glaciers are periglacial alpine landforms that are found in many locations worldwide whereas well developed models of deformation are established for traditional alpine glaciers rock glacier deformation is poorly understood geophysical data from lone peak rock glacier lprg southwest montana usa are paired with lidar bare earth 1m digital elevation model dem analysis to explore potential genetic relationships between internal composition structure and regularly spaced arcuate transverse ridges expressed at the rock glacier surface the internal composition of lprg is heterogeneous with frozen debris and clean ice overlain by an unconsolidated talus mantle upslopedipping clearly distinguished reflectors in the ground penetrating radar gpr longitudinal survey at lprg correspond to transverse ridges the spacing and slope of individual features at the surface and in the subsurface were measured and compared and are found to be similar the structures observed at lprg and other rock glaciers are similar to structures detected in glaciotectonically altered sediment ice cored moraines and other rock glacier settings this finding suggests that transverse ridges on rock glaciers may be used as geomorphic indicators of internal deformation this study contributes to the body of research on the application of gpr to rock glaciers and is the first to directly pair and analyze individual surface topographic features with internal structures

earthquakes and folding coalinga california the magnitude 6 6 coalinga earthquake of may 2 1983 and most of the other earthquakes of magnitude 4 and greater near that town are tentatively attributed here to flexural slip on the flanks of growing folds this explanation apparently conflicts with the 100 yr old theory that all tectonic earthquakes are caused by slip on faults perhaps the coalinga events in an area where no active faults had been mapped will serve to suggest another possible mechanism for the generation of some earthquakes here the strongly folded and long coalinga anticline and syncline in a thick stratigraphic section seem to require a mechanism of bedding plane slip the magnitude 2 5 lompoc earthquake of april 7 1981 can also be attributed to flexural slip on the limb of a fold flexural slip bedding plane slip usually unseen and unmappable is clearly revealed in several areas in southern california many small earthquakes may be produced in these and other areas where direct evidence of active flexural slip by folding is unavailable if the may 2 coalinga earthquake was caused by folding unusual geologic conditions may be responsible for its high intensity

seismic potential revealed by surface folding 1983 coalinga california earthquake the 2 may 1983 coalinga california earthquake magnitude 6 5 failed to rupture through surface deposits and instead elastically folded the top few kilometers of the crust the subsurface rate of fault slip and the earthquake repeat time are estimated from seismic geodetic and geologic data three larger earthquakes up to magnitude 7 5 during the past 20 years are also shown to have struck on reverse faults concealed beneath active folds

complex kame belt morphology stratigraphy and architecture the development of glacier karst at the margins of melting ice sheets produces complex glaciofluvial sediment landform assemblages that provide information on ice sheet downwasting processes we present the first combined geomorphological sedimentological and geophysical investigation of the brampton kame belt an important glaciofluvial depositional zone at the centre of the last british irish ice sheet ground penetrating radar gpr data allow the broad scale internal architecture of ridges eskers and flat topped hills ice walled lake plains to be determined at four sites in combination with sediment exposures these provide information on lateral and vertical variations in accretion styles depositional boundaries and grain size changes building on existing work on the subject we propose a refined model for the formation of ice walled lake plains resulting from the evolution and collapse of major drainage axes into lakes as stable glacier karst develops during deglaciation the internal structure of esker ridges demonstrates variations in sedimentation that can be linked to differences in ridge morphologies across the kame belt this includes low energy flow conditions and multiple accretion phases identified within large s n oriented esker ridges and fluctuating water pressures hyperconcentrated flows and significant deformation within a fragmented sw ne oriented esker ridge in combination with updated geomorphological mapping this work allows us to identify two main styles of drainage within the kame belt 1 major drainage axes aligned broadly s n that extend through the entire kame belt and collapsed into a chain of icewalled lakes and 2 a series of smaller fragmented sw ne aligned esker ridges that represent ice marginal drainage as the ice sheet receded south eastwards up the vale of eden our study demonstrates the importance of integrated geomorphological sedimentological and geophysical investigations in order to understand complex and polyphase glaciofluvial sediment landform assemblages

three dimensional hydrostratigraphy of the orangeville moraine area southwestern ontario canada regional scale three dimensional modelling of quaternary sediments in the orangeville moraine area of southwestern ontario has been completed as part of the ontario geological survey groundwater in

using a multiple variogram approach to improve the accuracy of subsurface geological models subsurface geological models are often used to visualize and analyze the nature geometry and variability of geologic and hydrogeologic units in the context of groundwater resource studies the de

effects of confining stress density and initial static shear stress on the cyclic shear response of fine grained unclassified tailings a constant volume direct simple shear apparatus was used to investigate the effects of confining stress initial static shear stress and void ratio on the liquefaction resistance of fine grained tailings the cyclic resistance ratio also expressed as the overburden stress correction factor was found to decrease with increasing confining stresses in the range 100 400 kpa and to gradually increase from 400 kpa onwards when samples were tested at the same initial void ratio the presence of an initial static shear stress decreased the liquefaction resistance a key outcome of the work was to reveal the critical importance of density on liquefaction susceptibility of compressible tailings thus a combined correction factor to account for overburden stress and density on cyclic resistance was proposed

morphology and gpr stratigraphy of a frontal part of an end moraine of the laurentide ice sheet paris moraine near guelph on canada abstract during deglaciation the laurentide ice sheet developed lobate ice termini in the great lakes area where the lobes remained quasi stationary for considerable time and sediment was supplied by the glacier end moraines fronted by outwash plains were formed one of the best examples in southern ontario is the paris moraine formed by the lake ontario lobe this study is a detailed examination of the morphology transverse and longitudinal of part of the paris moraine near guelph ontario and an analysis of the stratigraphy as derived from borehole information and ground penetrating radar gpr surveys parts of the northwestern frontal zone of the moraine are characterized by c 30 m high semi isolated hills composed in great part by aprons fans of debris flow and waterlaid sediments to the southeast these hills are backed by moat like depressions similar to those formed by ice push generating hill hole morphology the ice push effect is corroborated by evidence of folding and dislocation in the gpr profiles farther southeastward still the main body of the end moraine is characterized by hummocky topography typical of differential melting of sediment charged stagnant ice

influence of strain history on postliquefaction deformation characteristics of sands abstract an experimental study aimed at improving the understanding of the role of maximum cyclic strain during earthquake loading on the subsequent response of liquefied sands is presented the behavior of two sands one generally strain hardening and the other strain softening over a range of stress and density states during virgin monotonic loading is presented to demonstrate that regardless of whether a sand is contractive or dilative in preliquefaction loading its response following liquefaction is dilative it is shown that postliquefaction stress strain behavior can be characterized by four distinct phases the influence of relative density confining stress and the level of maximum shear strain during earthquake loading prior to liquefaction preliquefaction strain preliq on the response of liquefied sand varies during each of these phases the first phase of deformation essentially at zero stiffness is highly dependent on the level of preliquefaction strain but is not significantly affec

subsurface heterogeneity in the geological and hydraulic properties of the hummocky paris moraine guelph ontario the advance and retreat of ice lobe margins of the laurentide ice sheet formed moraines that are a prevalent feature throughout southwestern ontario in contrast to the well studied stratified moraine complexes recessional and end moraines have largely been ignored in the context of hydrogeological studies recent urban growth has led to development pressures on these moraines and a need to better understand their hydrogeology this study presents data sets from the paris moraine near guelph ontario to examine its geomorphology internal composition and the corresponding hydraulic properties of these ice marginal features the moraine s geomorphic elements were mapped using high resolution global positioning system transects aerial photograph analysis and ground truthing nine continuous sediment cores were recovered to determine the nature and distribution of subsurface sedimentary units and their relation to the regional stratigraphic framework cores were described in detail using standard sedime

large scale in situ test for mechanical characterization of soil rock mixture used in an embankment dam abstract to improve the mechanical behavior of core wall in higher embankment dams soil rock mixture obtained by mixing rock blocks to the cohesive soil is used for the first time as the core wall material of the nuozhadu embankment dam china the differences in the mechanical behavior of soil and soil rock mixture samples are studied in depth two large scale compaction test fields and a series of in situ direct shear tests have been conducted on soil and soil rock mixture samples the mixing of rock blocks changes the deformation behavior of the sample the existence of rock blocks makes the deformation modulus and the internal friction angle of soil rock mixture greater than that of the soil sample while decreasing its cohesive force

a quantitative three dimensional depositional model of gravelly braided rivers a quantitative three dimensional depositional model of gravelly braided rivers has been developed based largely on the deposits of the sagavanirktok river in northern alaska these deposits were described using cores wireline logs trenches and ground penetrating radar profiles the origin of the deposits was inferred from observations of 1 channel and bar formation and migration and channel filling interpreted from aerial photographs 2 water flow during floods and 3 the topography and texture of the river bed at low flow stage this depositional model quantitatively represents the geometry of the different scales of strataset the spatial relationships among them and their sediment texture distribution porosity and permeability in the model are related to sediment texture the geometry of a particular type and scale of strataset is related to the geometry and migration of the bedform type e g ripples dunes bedload sheets bars associated with deposition of the strataset in particular the length to thickness ratio of stratasets is similar to the wavelength to height ratio of associated bedforms furthermore the wavelength and height of bedforms such as dunes and bars are related to channel depth and width therefore the thickness of a particular scale of strataset i e medium scale cross sets and large scale sets of inclined strata will vary with river dimensions these relationships between the dimensions of stratasets bedforms and channels mean that this depositional model can be applied to other gravelly fluvial deposits the depositional model can be used to interpret the origin of ancient gravelly fluvial deposits and to aid in the characterization of gravelly fluvial aquifers and hydrocarbon reservoirs

cyclic behaviour of reconstituted and desiccated rewet thickened gold tailings in simple shear a simple shear apparatus norwegian geotechnical institute ngi type has been used to investigate the mechanical behaviour of gold tailings under monotonic cyclic and post cyclic loading specimens were prepared either by reconstituting the tailings at different water contents or by employing a dry wet preparation technique the latter technique attempted to simulate a realistic stress history for thickened tailings deposition by preparing the specimen at the pumping water content and subsequently allowing it to settle and then desiccate to a target water content subsequently these specimens are rewetted and then consolidated cyclic resistance ratios for specimens prepared by the dry wet preparation technique were considerably higher than those of specimens prepared by the standard technique though there appears to be no advantage in drying the tailings past the shrinkage limit in general the tailings could experience significant deformation during cyclic and post cyclic loading irrespective

an evaluation of direct simple shear tests on clay normally consolidated samples of kaolin have been tested in two direct simple shear apparatuses the first apparatus is specially instrumented with load cells in the horizontal boundaries to investigate the uniformity of the stresses acting on the samples the internal deformations and strains are determined using radiographic techniques the radial stress is determined from membranes reinforced with resistance wire the second apparatus is a standard commercially available device supplied by geonor the stresses and strains are shown to be uniform in the central region of the sample away from the vertical boundaries until failure values of the stress and strain variables determined from the central region are representative of a uniform simple shear deformation in plane strain in all tests the samples fail by developing approximately horizontal ruptures values of the shear modulus and shear strength estimated from the average stresses in the geonor apparatus underestimate by approximately 10 the

structure and genesis of the thabor rock glacier northern french alps determined from morphological and ground penetrating radar surveys landform analysis and ground penetrating radar gpr were used to investigate the thabor rock glacier in the northern french alps the surface features of the rock glacier were classified and described with emphasis on massive ice exposures the retreat of the former thabor glacier since the little ice age lia was documented through an analysis of historical sources and recent movements of the rock glacier were inferred from orthophoto based measurements two dimensional 2 d models of the radar wave velocity were derived from the raw gpr data using the numerous diffraction hyperbolae for local determinations of the velocity and kriging interpolation techniques subsequently the profiles were migrated through a 2 d kirchhoff migration method using the interpolated velocities the 2 d velocity models exhibit pronounced spatial variations and in several locations high values 0 15 m ns 1 potentially corresponding to massive ice on the other hand while the migrated profiles show numerous layers the internal stratigraphy of the rock glacier is dominated by a few prominent internal boundaries the integration of morphology radar wave velocity and internal stratigraphy allowed us to identify the main structural units of the rock glacier as well as to explain its genesis the rock glacier was formed by the imbrication of a massive ice core originating from the retreat of the former thabor glacier since the lia into pre existing glacial deposits

landform characterization using geophysics recent advances applications and emerging tools abstract this paper presents an overview of the strengths and limitations of existing and emerging geophysical tools for landform studies the objectives are to discuss recent technical developments and to provide a review of relevant recent literature with a focus on propagating field methods with terrestrial applications for various methods in this category including ground penetrating radar gpr electrical resistivity er seismics and electromagnetic em induction the technical backgrounds are introduced followed by section on novel developments relevant to landform characterization for several decades gpr has been popular for characterization of the shallow subsurface and in particular sedimentary systems novel developments in gpr include the use of multi offset systems to improve signal to noise ratios and data collection efficiency amongst others and the increased use of 3d data multi electrode er systems have become popular in recent years as they allow for relatively fast and detailed mapping novel developments include time lapse monitoring of dynamic processes as well as the use of capacitively coupled systems for fast non invasive surveys em induction methods are especially popular for fast mapping of spatial variation but can also be used to obtain information on the vertical variation in subsurface electrical conductivity in recent years several examples of the use of plane wave em for characterization of landforms have been published seismic methods for landform characterization include seismic reflection and refraction techniques and the use of surface waves a recent development is the use of passive sensing approaches the use of multiple geophysical methods which can benefit from the sensitivity to different subsurface parameters is becoming more common strategies for coupled and joint inversion of complementary datasets will once more widely available benefit the geophysical study of landforms three cases studies are presented on the use of electrical and gpr methods for characterization of landforms in the range of meters to 100 s of meters in dimension in a study of polygonal patterned ground in the saginaw lowlands michigan usa electrical resistivity tomography was used to characterize differences in subsurface texture and water content associated with polygon swale topography also a sand filled thermokarst feature was identified using electrical resistivity data the second example is on the use of constant spread traversing cst for characterization of large scale glaciotectonic deformation in the ludington ridge michigan multiple cst surveys parallel to an 60 m high cliff where broad 100 m synclines and narrow clay rich anticlines are visible illustrated that at least one of the narrow structures extended inland a third case study discusses internal structures of an eolian dune on a coastal spit in new zealand both 35 and 200 mhz gpr data which clearly identified a paleosol and internal sedimentary structures of the dune were used to improve understanding of the development of the dune which may shed light on paleo wind directions

effects of gravel content on shear resistance of gravelly soils abstract shallow landslides in colluvium which generally consists of wide particle gradation in a loose state occur in steep slope terrains to perform stability analyses shear strength parameters that represent soil constituents in situ stress state and shearing mode are needed this experimental study investigates the effects of gravel content on the shearing characteristics of gravelly soils based on the intergrain state concept a series of drained simple shear tests was performed on reconstituted specimens of gap and well graded sands with various gravel content levels the results reveal that 1 the shear strength of gravelly soils depends on the packing condition of dominant particles with the intergrain granular void ratio being a more representative parameter for the soil packing condition than the global void ratio 2 the drained shear strength of loose gravelly sand is dominated by sand matrix properties with the inclusion of gravel content reducing the strength by no more than 20 compared to that of pure sand 3 the strength parameters of sand like gravelly soils can be estimated from the sand matrix with proper reduction

a detection method of subrecent to recent tectonic activity in the anticlinal system of the northern negev israel geomorphological and geophysical methods combined with borehole information were employed to search for possible subrecent small scale vertical movement along the anticlinal fold belt of the central negev israel such tectonic deformation might indicate displacement on the buried reverse faults underneath the anticlines

strength of various sands in triaxial and cyclic direct shear tests abstract this paper presents the result of an extensive series of experimental investigation carried out in triaxial and cyclic direct shear tests on sands having various properties which were obtained from different locations in turkey and in northern cyprus in order to investigate the link between strength and physical properties i e shape of the sand particles three series of triaxial tests consolidated drained cd consolidated undrained cu and unconsolidated undrained uu for each were performed under three different confining pressure values 450 kpa 500 kpa and 550 kpa with a back pressure of 400 kpa the cyclic shear behaviour of the sands was tested by considering the normal stresses of 50 kpa 100 kpa and 150 kpa experimental results in both triaxial and cyclic direct shear tests showed a relation between the physical properties of the sands and the behaviour of them under monotonic and cyclic loading the given pictures show the physical differences similarities among the sands used during the investigation the goal of the presented experimental investigation is to have an understanding of the behaviour due to shape characteristics i e roundness sphericity of these four types of sands narli birecik trakya and crushed stone which are widely used in earthwork projects in certain parts of turkey and northern cyprus

the active temperate glacial landsystem a model based on breiðamerkurjokull and fjallsjokull iceland accurate interpretations of ancient glaciated terrains rely heavily on our knowledge of process form relationships in contemporary glacierized basins a landsystems model for temperate actively receding glaciers is presented based upon brei amerkurjokull and fjallsjokull iceland historical documentation maps and or aerial photography documenting recession since 1903 provide a unique series of snapshots of the evolving glacial geomorphology at these snouts this documentation is employed in association with sedimentological investigations to assess the evolution of sediment landform assemblages at active temperate glacier margins using the wealth of geomorphological and sedimentological information produced during the recent recession of brei amerkurjokull and fjallsjokull three depositional domains are recognized 1 areas of extensive low amplitude marginal dump push and squeeze moraines derived largely from material on the glacier foreland and often recording annual recession of active ice 2 incised and terraced glacifluvial forms such as recessional ice contact fans and hochsandur fans and simple and complex anabranched eskers and small areas of pitted outwash 3 subglacial landform assemblages of flutes drumlins and overridden push moraines located between ice marginal glacifluvial depo centres the lack of supraglacial sediment in active temperate glaciers like brei amerkurjokull and fjallsjokull generally precludes the widespread development of chaotic hummocky moraine the hummocky terrain previously termed kame and kettle topography has mostly evolved by melt out into a complex network of anabranched eskers over the period 1945 1998 or actually comprises pitted or kettled outwash sandar the tills across the foreland were emplaced by subglacial deformation and lodgement and comprise materials derived from pre existing stratified sediments in addition to localized abrasion of rock surfaces and patches of lake sediments till sequences thicker than 2 m have been constructed by the sequential plastering of till layers onto stratified sediments and bedrock because this stacking is a sub marginal process it is suggested that complex till sequences similar to those observed at brei amerkurjokull fjallsjokull may be employed in the reconstruction of ancient glacier margins additionally the geomorphology of the active temperate landsystem at east brei amerkurjokull may contain subtle surge signatures verifying the historical record of small surges by this part of the glacier this illustrates the danger of employing landform sediment associations from restricted study areas e g parts of landsystems as representative process form models for glaciated terrains

three dimensional swelling of clay lumps the disposal of large volumes of clay lumps obtained from underground construction activities and seabed dredging is a problem in a highly built up environment such as singapore the use of such clay lumps for reclamation of land is an environment friendly proposition the clay lumps when placed under water will undergo three dimensional swelling calculation of the degree of swelling is important for making decisions on when to place surcharge and in what quantity on top of the fill for closing the inter lump voids this paper reports the results of experimental and numerical studies that were carried out to understand the swelling behaviour of clay lumps when placed under water experimental results were compared with finite element method results using linear and non linear elastic models the study shows that the suction present in the lumps increases initially before dissipation suggesting the presence of the cryer mandel effect during three dimensional swelling the importance of simulating co

georadar facies and glaciotectonic structures in ice marginal deposits northwest zealand denmark ground penetrating radar gpr measurements have been carried out on an outwash plain and in the rim of an adjacent ice push ridge in northwest zealand denmark the radar profiles are differentiated into radar facies with distinct reflection characteristics the lithology and depositional environment of the radar facies is interpreted by correlating information from profiles in gravel pits geological maps and bore hole data the gpr profiles reveal sedimentary structures and glaciotectonic deformation structures several thrust planes and folds are interpreted from the gpr data the deformation style of the tectonised glaciofluvial sediments is a pro glacial thin skinned thrust complex with associated folding the deformations have resulted in the present ridge morphology seen in the rim of the ice push ridge on top of the deformed sediments and in front of them penecontemporaneous and post tectonic sediments are deposited smoothing the ridge relief created by the thin skinned thrust complex

geohazards and large geographically distributed systems a general classification for scale in geotechnical engineering is used to explore the modelling of large geographically distributed systems and their response to geohazards both component and network performance are reviewed with respect to components prototype scale experiments of underground pipeline response to abrupt ground deformation are described including control of soil properties soil pipeline interaction and performance of high density polyethylene pipelines direct shear ds apparatus size is shown to have a significant effect on ds strength and the most reliable ds device is identified from comparative tests with different equipment mohr coulomb strength parameters for partially saturated sand are developed from ds test data and applied in finite element simulations of soil pipeline interaction that show excellent agreement with prototype scale experimental results apparent cohesion measured during shear failure of partially saturated sand is caused by suction induced dilatancy wi

response of alluvial rivers to slow active tectonic movement alluvial rivers respond to valley slope deformation caused by active tectonics in various ways depending on the rate and amount of surficial deformation and on the type of river on the basis of experimental results and field examples hypothetical models of river response to anticlinal uplift and synclinal subsidence were developed for different types of alluvial rivers an experimental braided channel responded to anticlinal uplift across the channel with degradation and terrace formation in the central part of the uplift with subsidence aggradation in the central reach was the main response transverse bars developed downstream of the subsidence axis an experimental meandering channel responded to slope steepening with a sinuosity increase bank erosion and point bar growth occurred downstream of the anticlinal axis and upstream of the synclinal axis upstream of the uplift axis and downstream of the subsidence axis where the slope was flattened water flooded over bars local convexity in longitudinal profiles of the middle rio grande new mexico is considered to be formed by a domal uplift local aggradation and degradation could be explained by the effect of uplift the san joaquin river california which is now highly controlled does not show clear adjustment to the rapid subsidence due to ground water withdrawal it shows however a channel pattern adjustment to active tectonic subsidence that has been occurring for a long time the san antonio and guadalupe rivers in texas both increase their sinuosity significantly where monoclinal movements steepen valley slopes

determination of the shearing behaviour of root permeated soils with a large scale direct shear apparatus abstract soils with roots or root like inclusions have often been tested in direct shear to quantify the effects of vegetation on the shear strength of soil and in turn the stability of slopes however a straightforward evaluation of root reinforcement is challenging due to the complex nature of roots and the dependency of soil behaviour on many factors an inclinable large scale direct shear apparatus ildsa was built to study the shearing behaviour of root permeated soils planted specimens consisting of two different sets of species were prepared with a moraine sampled from a recent landslide location and tested in direct shear subsequent to saturation relationships of peak stress ratio with dry weight of roots maximum dilatancy angle and void ratio were investigated to evaluate the behaviour of root permeated soil the combined approach of taking both presence of roots and dilatant behaviour of soil into consideration results in a more realistic understanding and quantification of the effects of root reinforcement at least for laboratory testing of root permeated soils

effect of static shear stress on the cyclic resistance of sands in simple shear loading an experimental study of the effect of initial static shear stress on the undrained simple shear response of sands is presented liquefaction resistance of two sands one generally contractive and the other dilative over a wide range of density and effective stress levels was evaluated at various density and stress states at a given density the effect of static shear on the cyclic resistance of sands is dependent on the type of stress strain response that ensues during loading the general notion that static shear increases the cyclic resistance of sands at relatively high densities is not valid if the sand is contractive at the denser state the k correction factor for sand at 80 relative density may be as low as about 0 6 for strain softening sand depending on the initial stress state the routine industry practice of disregarding the k factor in dense sands may thus lead to unsafe designs in such materials the k values measured under cyclic simple shear loading are compared to the k values

a pre paris ice sheet limit near guelph southern ontario the guelph moraine a previously undesignated end moraine between hespeler and rockwood is described and shown to be the consequence of a limited readvance that interrupted the general recession from the guelph area of ice that deposited the port stanley till rather than of a precursive advance of younger ice that laid down the wentworth till and eventually produced the paris moraine from rockwood and following broadly the eramosa speed river a gravelly outwash train is traced southwest toward hespeler where it appears to merge with sandier deposits of grand river provenance and to pass into an extensive sand plateau south of the town these pre guelph sands and gravels were overridden by ice at rockwood and southwest of guelph during the readvance meltwaters were forced at first to detour westward along the upper speed river and ellis creek valleys but later found their way beneath ice at rockwood to initiate subglacial erosion of the gorges and adjacent dry valley systems the eramosa speed spillwa

alluvial river response to neotectonic deformation in louisiana and mississippi repeat geodetic surveys show uplift of the monroe and wiggins anticlines in louisiana and mississippi there are deformed quaternary terraces which indicate long term deformation in the valleys of the alluvial rivers that cross these structures and there are floodplain and channel convexities that provide evidence of modern deformation in addition the channels show significant variations of morphology sinuosity gradient and depth and behavior appropriate to reaches of increased and decreased valley slope these alluvial rivers are adjusting to modern deformation and their adjustment confirms two geodetic leveling anomalies

detailed internal architecture of a fluvial channel sandstone determined from outcrop cores and 3 d ground penetrating radar example from the middle cretaceous ferron sandstone east central utah ideally characterization of hydrocarbon reservoirs requires information about heterogeneity at a submeter scale in three dimensions detailed geologic information and permeability data from surface and cliff face outcrops and boreholes in the alluvial part of the ferron sandstone are integrated here with three dimensional 3 d ground penetrating radar gpr data for analysis of a near surface sandstone reservoir analog in fluvial channel deposits the gpr survey covers a volume with a surface area of 40 x 16 5 m and a depth of 12 m five architectural elements are identified and described in outcrop and well cores using a sixfold hierarchy of bounding surfaces internally the lower four units consist of fine grained parallel laminated sandstone and the upper unit consists of medium grained trough cross bedded sandstone the same sedimentary architectural elements and associated bounding surfaces are distinguished in the gpr data by making use of principles developed in seismic stratigraphic analysis to facilitate comparison of geologic features in the depth domain and radar reflectors in the time domain the radar data are depth migrated the gpr interpretation is carried out mainly on migrated 100 mhz data with a vertical resolution of about 0 5 m measures of the spatial continuity and variation of the first and second order bounding surfaces are obtained by computing 3 d experimental variograms for each architectural element each radar begin page 1584 facies the maximum correlation length of the dominant internal features ranges between 4 and 6 m and the anisotropy factor ranges between 0 6 and 0 95

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

integrating geomorphological mapping trenching insar and gpr for the identification and characterization of sinkholes a review and application in the mantled evaporite karst of the ebro valley ne spain abstract this contribution illustrates the advantages of integrating conventional geomorphological methods with insar ground penetrating radar and trenching for sinkhole mapping and characterization in a mantled evaporite karst area where a significant proportion of the karstic depressions have been obliterated by artificial fills the main practical aim of the investigation was to elucidate whether buried sinkholes overlap the areas planned for the construction of buildings and services in order to apply a preventive planning strategy old aerial photographs and detailed topographic maps were the most useful sources of information for the identification of sinkholes and helped to obtain information on their chronology either a minimum age or bracketing dates the insar technique provided subsidence rate values ranging from 4 4 to 17 3 mm yr consistent with the spatial distribution of the mapped sinkholes this quantitative deformation data helped corroborating independently the existence of active buried sinkholes and improving the delineation of their limits the gpr profiles contributed to the precise location of sinkhole edges provided information on the geometry of buried sinkholes and deformation structures and helped to site trenches and to rule out the existence of sinkholes in particular areas the main input derived from the trenches includes 1 confirming or ruling out anomalies of the gpr profiles attributable to subsidence 2 precise location of the edge of some filled sinkholes 3 information on subsidence mechanisms recorded by various deformation structures and cumulative subsidence magnitude 4 calculating minimum long term subsidence rates using radiocarbon dates obtained from deformed sinkhole deposits 5 unequivocal evidence of active subsidence in areas assigned for the construction of buildings

structure transitions of clay fills in north western bohemia laboratory investigations of a clayey material from a fill created during open cast coal mining are presented standard laboratory experiments direct shear box oedometer have been supplemented by large scale testing the mechanical behaviour of the fragmentary soil is influenced by the presence of macrovoids and shows further size and time effects which makes the description of the clay fill behaviour difficult the initially fragmentary structured soil changes with time back to a homogeneous material due to weathering processes and through geostatic load partial saturation of the fragments also contributes to the peculiar behaviour of the clay fill material

the hydrogeological attributes and mechanisms of a receding sedimentary terrain in the anambra basin southern nigeria this research investigated the hydrogeological aspects associated with severe gulling and landsliding on a vulnerable sedimentary terrain in the context of the newly identified deformation patterns and large numbers of recently discovered scars clustering slopes on identical coordinates results of field survey remote sensing vertical electrical sounding and experimental analyses were presented to explain the causes and mechanisms of the mass movements ravaging the terrain a digital elevation model accurately captured the diverse geomorphologic elements including landslide scars hills ridges valleys plains and rivers that matched field observations the model aided the identification of previously unknown steep incised channels active headcuts unstable side walls and a seasonal river flowing near the slopes having large number of landslide scars it was observed that areas that lay on higher elevations where the clusters occur were dominated by fresh scars while the moderate to low elevations were dominated by older ones majority of the slope failures initiated within the sandstone as shallow slides 1 m to the sliding surface covering 104 m2 with short runout distances bigger landslides although few occurred as isolated individual events initiated at the sandstone shale boundary on distinct slopes the steepness of the slopes seemed controlled by slope morphology concavity which probably influenced the number and distribution of landslide events the steeper slopes were more concave and had the highest concentration of scars shallow water table 4 11 m and increased instability brittleness index under increasing over consolidation ratio are the critical failure factors

quantification of mechanical and hydric components of soil reinforcement by plant roots the use of vegetation to stabilize slopes with regard to shallow landslides is an ecological and economic alternative to traditional solutions of civil engineering this study aims at quantifying the effect of soil water content on the reinforcement of soil by plant roots and determines how soil water content influences the failure modes of roots during shear direct shear box tests were performed on three species used in hillslope reforestation programs in yunnan china reinforcement was quantified and divided into a hydric component corresponding to the effect of water removal and a mechanical component reflecting the influence of roots on apparent cohesion and friction angle it was shown that the hydric component of reinforcement can be of the same order as the mechanical component and that root system architectural traits influence the type of mechanical reinforcement cohesive or frictional we also demonstrate the potential development of matric suction effects on the shear strength of soil

interpretation of direct shear box testing of sands as quasi simple shear interpretation of the direct shear box dsb test implicitly assumes a simple shear mode of deformation but this assumption has not been fully verified in particular in tests on sands this paper describes a laboratory investigation which was commissioned to find an optimum configuration of a dsb apparatus for measuring the strength and dilatancy characteristics in direct simple shear the examination was made in a newly developed dsb apparatus using dry specimens of two standard sands toyoura sand and silver leighton buzzard sand boundary effects such as the wall friction the size of the opening between the two halves of the shear box and the constraint imposed by the loading platen were each independently examined in pilot tests to determine their influence on the measurements of strength and angle of dilatancy the optimum configuration was determined through careful examination of the boundary stresses and strains of rectangular specimens subjected to shearing under drained and constant volume

application of suction stress for estimating unsaturated shear strength of soils using direct shear testing under low confining pressure the primary objective of this study is to evaluate effects of suction on shear strength of unsaturated soils under low confining pressure and to examine the relationships between suction shear strength behavior and volumetric deforma tion using newly developed direct shear testing equipment for compacted weathered granite soils the soil water retention curves swrcs of unsaturated soils were obtained under various overburden pressures to analyze test results from the direct shear test under unsaturated conditions a new method suction stress swrc method ssm is proposed to deter mine the suction value for each overburden pressure and the suction stresses as a result it has been found that the stress states at the peak shear strength point are on the same failure line for the saturated state when the suction stress is treated as a component of confining pressure the relationship between stress ratio and dilatancy for the saturated state can be ex tended to the unsaturated state it is also noted that the estimated unsaturated shear strengths using the ssm agree well with the measured values from laboratory testing

the pleistocene end moraine fans controls on their sedimentation and location abstract this paper presents a model of end moraine sedimentation based on data from pleistocene ice sheet margins according to this model end moraines quite often constitute alluvial fans or coalesced fans formed at the ice margin by redeposition of supraglacial material three types of end moraine fan have been recognized those composed mainly of mass flow deposits type a equivalent to dry alluvial fan in nonglacial settings those containing both mass flow and waterlain sediments type b and those that contain mainly sorted waterlain material type c equivalent to wet alluvial fan in nonglacial settings for each type of fan several sedimentary subenvironments differentiated by distance from the ice front are identified the diagnostic processes on the end moraine fans are cohesive and cohesionless debris flows or grain flows types a and b or hyperconcentrated flows and sheetflows types b and c the type b fan seems to represent the most typical sequence in the end moraine zones but the type c fan is also quite common at the pleistocene ice sheet margins our studies also suggest that the terminal supraglacial drainage controls the type of end moraine fan sedimentary subenvironment moraine types a b c whereas subglacial hydrology and ice stream regime which determine the mobility of the ice front and larger scale conditions of sediment supply to the ice margin control the location and size of the end moraine fan

composition and construction of late pleistocene end moraines durango colorado the late pleistocene animas city 2 and animas city 3 end moraines at the north edge of durango colorado were built at the terminus of the animas glacier as ice marginal aprons of primarily debris flow sediment interbedded with sandy stream sediment sorted sediment and three types of diamicton present in the moraines are interpreted as fluvial sediment lacustrine sediment debris flow sediment and melt out till melt out till at one locality represents deposition from the basal debris rich parts of the animas glacier onto the proximal side of the animas city 3 moraine glaciotectonic features in a coarsening upward sequence of sediment previously deposited in a proglacial moraine dammed lake mark a readvance of the animas glacier to the animas city 3 moraine based on the character of the sediments and their interbedding we conclude that the existing moraines were built rapidly in