tectonic history of the lunksoos composite terrane in the maine appalachians several ordovician volcanic terranes are preserved between the paleozoic north american margin and the avalon terrane in the northern appalachians of maine they have been interpreted as remnants of an island arc on the basis of their current position in the appalachians or as ocean islands near the margin of avalon on the basis of paleontologic data a study of one of these terranes the lunksoos terrane in northern maine was undertaken through a combination of paleomagnetic and structural analyses in order to understand its tectonic evolution paleomagnetic study of the pre caradoeian pre late ordovician stacyville volcanics revealed three components of magnetization the final magnetization removed d 90 i 36 95 11 8 is interpreted to be primary and yields a paleolatitude of approximately 20 s however a late ordovician remagnetization cannot be excluded the stacyville volcanics now overlie a cambrian and lower ordovician sequence the grand pitch and shin brook formations that is believed to have been deposited at the southern side of iapetus possibly near the margin of avalon during the middle and late ordovieian avalon was at paleolatitude s higher than 40 s while the volcanics were either formed or remagnetized at a paleolatitude of 20 s the pre caradocian stacyville volcanics therefore could not have been deposited directly on the grand pitch shin brook sequence but must have been tectonically emplaced the rockabema diorite which intrudes the entire cambro ordovician sequence constrains the timing of this emplacement to be pre late early silurian these relationships indicate that the lunksoos area is a composite terrane within the maine appalachians the tectonic emplacement scenario is unnecessary if the grand pitch and shin brook formations were not located on the south side of iapetus during the ordovician this alternative however poses conflicts with the interpretation of faunal affinities

observation and analysis of near surface pore pressure measurements in clay shales slopes clay shales largely outcrop in the northern apennines of italy where they are associated with frequent and widespread landslide activity the paper presents the results of monitoring activities carried out in two field sites and focused on the hydrology of clay shales prone to landsliding in the monitored slopes the water table is close to the ground surface throughout the year with seasonal fluctuations of tens of centimetres to a couple of metres shallow weathered soils or clay cover and unaltered material exhibit a much different behaviour although responses to single rainfalls are clearly identifiable as pressure pulses in the clay cover they are never observed in the underlying parental clay shales where downward gradients indicate recharge and only long term seasonal fluctuations are recorded short term variations of pressure head in the clay cover are ruled by downward propagation of a pressure wave in saturated conditions more than 400 pore pressure responses collected in the two sites are analysed in terms of lag time rate and amount of pressure increase and timing of pressure peaking it emerges that the linear diffusion theory can satisfactorily explain the observed behaviour in deeper unaltered material the barometric effect influences the measures similarly to what is observed in confined aquifers after its removal the corrected data exhibit regular seasonal fluctuations which are used to estimate the diffusivity of the material based on phase lag and attenuation of the downward propagating long term periodic pulse copyright 2011 john wiley sons ltd

origin and movement of groundwater and major ions in a thick deposit of champlain sea clay near montreal at a site near montreal piezometers and core samples were used to assess the origin age and rate of groundwater movement in a 28 m thick deposit of champlain sea clay 3h occurs only within the upper 3 4 m which indicates that groundwater below this surficial weathered zone originated prior to 1952 concentrations of 18o na and cl in water from the deepest piezometer suggest that the deep clay was deposited in a mixture of about 33 seawater and 67 freshwater profiles of several major ions show a gradual increase in concentration with depth mathematical simulations of vertical migration of ca2 mg2 k na and cl provide close matches to the field profiles when only upward diffusion of these ions into the surficial freshwater zone is included in the model with a diffusion time of approximately 10 000 a when the downward advection rate of 0 13 cm a 1 obtained from field measurements of hydraulic gradient and hydraulic conductivity is included in the model the simulated major ion profile

a multiscale study of the permeability of a thick clayey till we describe and evaluate two previously undocumented methods of bulk permeability k determination and compare results obtained with results of conventional smaller scale tests on the same thick clayey till deposit analysis of the downward propagation of seasonal water table fluctuations yielded bulk k of approximately 10 10 m s 1 in close agreement with results of laboratory consolidation and permeameter tests slug tests and distribution of vertical hydraulic gradient with depth in the deposit this agreement suggests that for such materials high gradient tests conducted at small scales of distance and time can provide reasonable estimates of bulk k the results also imply groundwater residence times in the till of thousands of years the flow pattern observed near a large excavation in the till was consistent with the initial recoveries of piezometers installed in much smaller boreholes assuming perturbation of hydraulic head in the formation due to borehole excavation time scales of these perturbations which prevent interpretation of measured hydraulic head using conventional well hydraulic methods varied from months to tens of years

hydrogeology of two saskatchewan tills i fractures bulk permeability and spatial variability of downward flow groundwater flow patterns were compared and contrasted in two deposits of clayey till of different thicknesses both of which overlie regional aquifers in a flat upland recharge area analysis of 67 field and laboratory hydraulic conductivity determinations indicated that conductive fractures in the unoxidized zone of the thinner till dalmeny site give rise to an isotropic bulk permeability of approximately 5 10 9 ms 1 which is two orders of magnitude greater than the bulk permeability of unoxidized till in the thicker deposit warman site vertical pore water velocities estimated using hydraulic and isotopic evidence vary greatly at dalmeny and appear to be of the order of 8 m in 10 000 yr at warman the association of vertical groundwater flux depth to water table and depth of oxidized zone at a given location is referred to as the flow regime there spatially detailed water level monitoring and test drilling indicated substantial variation of the flow regime at dalmeny on a horizontal scale of tens of meters no such variation exists at warman the differentiation of the flow regime at dalmeny is due to higher till permeability which permits a spatially variable response to microtopographically focussed infiltration of surface water recognition of the causes and symptoms of flow regime variability beneath flat till landscapes has implications for environmental assessment procedures agricultural practices wetland management and waste disposal

centrifuge modelling of hillslope debris flow initiation physical modelling of hillslope debris flow initiation was undertaken using the geotechnical beam centrifuge at the university of dundee the tests were carried out on model slopes consisting of soils with known properties prepared with constant initial density and material thickness the results showed that soils with a higher silt fraction can sustain a higher increase in pore water pressure and thus a greater reduction in effective stress before failure is induced this suggests that sand rich soils with lower fines content are geotechnically more susceptible to slope failure and that observed higher spatial frequencies of debris flow on slopes with coarse grained bedrocks can be partially explained in terms of lower critical pore pressure failure thresholds amongst the sandier soil matrixes produced from such lithologies differences in rates of water ingress into the model soils required to trigger a critical rise in pore pressures during the tests provide insights into the varying synoptic conditions and antecedent rainfall characteristics that are likely to trigger debris flows in different soil types

fossil evidence for fault derived stratigraphic repetition in the northeastern newfoundland appalachians two types of bedding parallel faults are common in the dunnage zone of eastern notre dame bay they are i early thrusts which together with bedding were rotated by later folding into steep attitudes and ii postfolding transcurrent faults both types of faults occur at all scales and give rise to repetitions in the stratigraphic sequence a compilation of the ages of various rock types based on fossil evidence indicates a relatively simple stratigraphy for the dunnage zone this interpretation appears to be at variance with many reported stratigraphic successions until repetitions by bedding parallel faulting are taken into account examples are given of sequences in which the repetition of various rock types dated by means of fossils is due to bedding parallel faulting we believe that the simple lithostratigraphy is a reliable aid for structural interpretations in areas where fossils are scarce or absent

observation and analysis of pore pressure fluctuations in a thin colluvium landslide complex near cincinnati ohio abstract field observations in a thin colluvium landslide complex along the ohio river near cincinnati show that measurable late winter and spring pore water pressure increases occur when several centimetres of rain fall over a period of one or more days average pre storm fillable porosity of 9 suggests that the colluvium was near saturation during the period of record dimensional analysis of flow through a sloping homogeneous layer of uniform thickness shows that short term pore pressure fluctuations in very nearly saturated soils can be approximated by a one dimensional linear diffusion equation the concept of slope parallel and slope normal characteristic times is also introduced to determine the conditions under which slope parallel and slope normal flow will predominate analytical solutions to the diffusion equation are then used to investigate the effects of storm frequency and magnitude on pore pressure fluctuations comparison of solutions for layers of finite and infinite thickness shows that an impermeable substrate nearly doubles pore pressures along the substrate for storms of short duration however the effect of an impervious boundary vanishes with increasing duration finally measured rainfall values are incorporated into a finite difference simulation of the observed pore pressures with good results

comment on tectonic history of the lunksoos composite terrane in the main appalachians by m reid wellensiek ben a van der pluijm rob van der voo and rex j e johnson

landslide kinematics and their potential controls from hourly to decadal timescales insights from integrating ground based insar measurements with structural maps and long term monitoring data abstract knowledge of kinematics is rudimentary for understanding landslide controls and is increasingly valuable with greater spatiotemporal coverage however characterizing landslide wide kinematics is rare especially at broadly ranging timescales we used highly detailed kinematic data obtained using photogrammetry and field mapping during the 1980s and 1990s and our 4 3 day ground based insar survey during 2010 to study kinematics of the large persistently moving slumgullion landslide the landslide was segregated into 11 kinematic elements using the 1980s 1990s data and the insar survey revealed most of these elements within a few hours averages of insar derived displacement point measures within each element agreed well with higher quality in situ observations averaging was deemed necessary because adverse look angles for the radar coupled with tree cover on the landslide introduced error in the insar results we found that the landslide moved during 2010 at about half its 1985 1990 speed but slowing was most pronounced at the landslide head gradually decreased precipitation and increased temperature between the periods likely resulted in lower groundwater levels and consequent slowing of the landslide we used gps survey results and limit equilibrium modeling to analyze changing stability of the landslide head from observed thinning and found that its stability increased between the two periods which would result in its slowing and the consequent slowing of the entire landslide additionally insar results suggested movement of kinematic element boundaries in the head region and our field mapping verified that they moved and changed character likely because of the long term increasing head stability on an hourly basis insar results were near error bounds but suggested landslide acceleration in response to seemingly negligible rainfall pore pressure diffusion modeling suggested that rainfall infiltration affected frictional strength only to shallow depths along the landslide s marginal faults highlighting their importance in controlling landslide stability hourly results also suggested that motion propagated along the 3 9 km length of the active landslide even following sub millimeter displacements while strengthening of landslide shear boundaries during faster movement was likely critical in regulating the landslide s motion hence detailed kinematic characterizations obtained from traditional and emerging approaches helped to reveal that mechanisms controlling landslide movement and evolution over decades also are critical to sub millimeter movement on a nearly continuous basis

ground based and uav based photogrammetry a multi scale high resolution mapping tool for structural geology and paleoseismology this contribution reviews the use of modern 3d photo based surface reconstruction techniques for high fidelity surveys of trenches rock exposures and hand specimens to highlight their potential for paleoseismology and structural geology we outline the general approach to data acquisition and processing using ground based photographs acquired from standard dslr cameras and illustrate the use of similar processing approaches on imagery from unmanned aerial vehicles uavs it is shown that digital map and trench data can be acquired at ultra high resolution and in much shorter time intervals than would be normally achievable through conventional grid mapping the resulting point clouds and textured models are inherently multidimensional x y z point orientation colour texture archival and easily transformed into orthorectified photomosaics or digital elevation models dems we provide some examples for the use of such techniques in structural geology and paleoseismology while pointing the interested reader to free and commercial software packages for data processing visualization and 3d interpretation photogrammetric models serve to act as an ideal electronic repository for critical outcrops and observations similar to the electronic lab book approach employed in the biosciences this paper also highlights future possibilities for rapid semi automatic to automatic interpretation of the data and advances in technology

fracture effects in the shallow groundwater zone in weathered sarnia area clay the sarnia area of southwestern ontario is underlain by thick deposits of clay rich glacial till from ground surface to between 4 and 6 m depth the clay till is fractured oxidized and penetrated by root holes the water table fluctuates seasonally between the ground surface and the bottom of the weathered zone water level response tests in conventional piezometers installed in augered holes in the weathered zone typically provide very low values of hydraulic conductivity 10 7 10 9 cm s which are similar to values obtained from the deeper unweathered and unfractured till the augering process creates a smeared clay zone along the borehole walls that significantly reduces measured hydraulic conductivity values in this study the weathered zone hydraulic conductivity was measured using unconventional piezometers a large diameter well and a tracer experiment between two test pits the smeared zone was removed or reduced around these installations and the measured weathered zone hydraulic conductivi

3d effects of permeability and strength anisotropy on the stability of weakly cemented rock slopes subjected to rainfall infiltration abstract weakly cemented sedimentary rocks with pronounced stratification exhibit permeability and strength anisotropy the influence of permeability and strength anisotropy on the groundwater flow and slope stability depends on the orientation of the bedding planes the stability of slopes with different orientations of bedding planes under rainfall infiltration was evaluated in this study using three dimensional finite element modeling the groundwater table and pore water pressure in slopes before and after rainfall were simulated and the calculated pore pressure corresponding to the initial and highest groundwater tables was used for slope stability analyses the results showed that in comparison with gently dipping bedding planes a slope with steeply dipping bedding planes exhibits a greater rise of the groundwater table and a greater increase of pore pressure leading to a larger reduction in the factor of safety also a shorter time is required to reach the highest groundwater table and the maximum pore pressure at a certain position in consideration of the anisotropic behavior and the groundwater table rise during rainfall unfavorable conditions were identified for the slope stability the four unfavorable conditions where the bedding planes and the slope face approximately strike in the same direction are 1 the daylight condition of the bedding planes 2 the coincidence of the bedding planes and the slope face and 3 steep bedding planes dipping out or 4 into the slope slopes with the unfavorable orientations of bedding planes need additional attention in order to ensure a safe land development in the mountainous areas

on subsurface stormflow predictions with simple kinematic theory for saturated and unsaturated flows this paper provides analytical solutions for some simple cases of subsurface stormflow the solutions are based on kinematic approximations in both unsaturated and saturated zones solutions for rising falling and partial equilibrium hydrographs are given the analytical model has been applied to data collected on a hillslope of the east twin brook catchment mendip united kingdom measured and predicted hillslope hydrographs were in good agreement

kinematic subsurface stormflow this paper builds on the analysis of henderson and wooding 1964 in comparing simplified models of subsurface stormflow for the case of a sloping soil mantle in which the hydraulic conductivity is constant throughout it is shown that models based on a kinematic wave formulation may be good approximations for those based on the extended dupuit forchheimier assumptions for values of the nondimensional parameter 4i cos k sin2 less than about 0 75 in terms of predicting both water table profiles and subsurface stormflow hydrographs by using this critical value of the range of values of slope angle and saturated hydraulic conductivity for which the kinematic approximation is valid can be specified a comparison is made with slope angles and hydraulic conductivities at field sites where subsurface stormflow has been shown to be an important component of catchment storm response it is concluded that the kinematic approximation may be useful for cases of practical interest

drones in carbonate geology opportunities and challenges and application in diagenetic dolomite geobody mapping unmanned aerial vehicles uavs or drones have become widely available for use in a broad range of disciplines despite the decreased cost and technological developments of platforms sensors and software the use of drones in carbonate geology has yet to be exploited nevertheless drones offer multiple advantages over traditional field work or high altitude remote sensing techniques in that they enable the reconstruction of three dimensional models of inaccessible or unsafe outcrops and can bridge the spatial scale gap in mapping between manual field techniques and airborne high altitude remote sensing methods in this contribution we present our methodology of structure from motion photogrammetry on drone captured images and highlight opportunities and challenges of using drones in carbonate geological studies moreover we apply this method to document the spatial distribution and dimensions of diagenetic dolomite geobodies in carboniferous limestone host rock of the picos de europa northern spain the results of our study indicate that dolomite geobodies occur preferentially near to strike slip faults rather than thrust faults or specific types of limestone host rock lithology in the study area the geobody dimensions appear to be related to the strain magnitude of the strike slip faults we propose that these identified links and controls are applicable to structurally controlled dolomitization on a more general basis our study has demonstrated the potential for using drones in carbonate geological studies

uav based remote sensing of the super sauze landslide evaluation and results unmanned aerial vehicles uavs equipped with digital compact cameras can be used to map landslides quickly and at a high ground resolution images taken by a radio controlled mini quad rotor uav of the super sauze france landslide have been used to produce a high resolution ortho mosaic of the entire landslide and digital terrain models dtms of several regions the uav capability for imaging fissures and displacements on the landslide surface has been evaluated and the subsequent image processing approaches for suitably georectifying the data have been assessed for super sauze horizontal displacements of 7 to 55 m between a high resolution airborne ortho photo of may 2007 and a uav based ortho mosaic of october 2008 have been measured fixed areas of persistent deformation have been identified producing fissures of different distributions and orientations comparable to glacial crevasses and relating directly to the bedrock topography the uav has demonstrated its capability for producing valuable landslide data but improvements are required to reduce data processing time for the efficient generation of ortho mosaics based on photogrammetric dtms in order to minimise georeferencing errors

a pore pressure diffusion model for estimating landslide inducing rainfall many types of landslide movement are induced by large rainstorms and empirical rainfall intensity duration thresholds for initiating movement have been determined for various parts of the world in this paper i present a simple pressure diffusion model that provides a physically based hydrologic link between rainfall intensity duration at the ground surface and destabilizing pore water pressures at depth the model approximates rainfall infiltration as a sinusoidally varying flux over time and uses physical parameters that can be determined independently if destabilizing pore pressures can be estimated then the model enables the development of a stability criterion defining destabilizing rainfall intensity duration conditions using a comprehensive data set from an intensively monitored landslide i demonstrate that the model is capable of distinguishing movement inducing rainstorms

slope stability models for rainfall induced lahars during long lasting eruptions abstract in this study we analyse the spatial distribution of potential lahar sources during long lasting eruptions using two slope stability models shalstab and trigrs the analysis is based on observed deposit grain size and thickness rainfall data and slope angle of the lahar events in the area surrounding the cordon caulle volcano chile that occurred during the 2011 eruption the main phase of the eruption 4 7 june was characterized by eruptive plumes from 7 to 11 km high which dispersed most of the tephra eastward toward argentina with a total estimated volume of about 1 km3 tephra fallout blanketed the region from ese to ene of the volcano with the thickness of the tephra fallout layers between approximately 1 m 15 km from vent and 0 06 m 240 km from the vent on 10 june 2011 a major lahar occurred close to the argentina chile border that reached the national road 231 28 km from the vent three field campaigns were undertaken to collect samples and data from tephra fallout deposits and triggering mechanisms in the lahar source area model input parameters were obtained from geotechnical tests and field measurements several metrics were used for model evaluation and best fit to the data were obtained for simulations considering non cohesive ash layers for shalstab and a cohesion of 0 5 kpa for trigrs both models are sensitive to the physical properties of the tephra fallout deposit and the hydraulic and materiel strength properties of the study area they both also show good agreement with field data but provide different information trigrs provides an estimate of the timing based on a storm event and location of a potentially unstable area while shalstab simulations result in landslide susceptibility classes based on critical rainfall value these outcomes provide fundamental insights into lahar triggering during long lasting volcanic eruptions and are crucial to the compilation of lahar hazard maps and emergency management plans in the south andes volcanic region

digital outcrop models applications of terrestrial scanning lidar technology in stratigraphic modeling abstract laser ranging is extremely accurate and efficient terrestrial scanning lidar light detection and ranging applied to outcrop stratigraphic mapping enables researchers to capture laser range data at a rate of thousands of individual x y z and laser intensity points per second these data in conjunction with complementary remotely and directly sampled data are used to conduct high precision facies characterization and to construct 3d geological computer models outcrop data are presented here to explain our workflow and to discuss the construction of rock based 3d digital outcrop models doms reproducibility and quantification are the drivers of this methodology high resolution terrestrial lidar acquisition processing interpretation and visualization are discussed and applied to mapping of geological surfaces in three dimensions laser generated models offer scientists an unprecedented visualization medium in a quantitative 3d arena applications of this technology include constructing and visualizing complex 3d earth models from outcrops for improved reservoir modeling flow simulation in hydrocarbon and aquifer systems and property modeling to constrain forward seismic modeling

origin age and movement of pore water in argillaceous quaternary deposits at four sites in southwestern ontario hydrogeologic information in the form of textural properties field and laboratory determined hydraulic conductivity values vertical hydraulic gradients from piezometer nests and major ion and isotopic contents 18o 2h 3h 13c 14c was obtained from four sites located in southwestern ontario on thick deposits of clayey till and glaciolacustrine clay at each site the piezometers were installed from the water table zone situated 1 4 m below the surface to a maximum depth between 20 and 35 m below the surface values of hydraulic conductivity determined in the laboratory by consolidometer and triaxial methods are in the order of 10 8 10 7 cm s and are similar to values calculated from rates of water level rise in piezometers mean values of average vertical groundwater velocity calculated with the measured values of hydraulic conductivity porosity and hydraulic gradient using the darcy equation for a saturated non fractured porous medium range from 0 13 to 0 26 cm yr tritiated pore waters only occur within 3 6 m of ground surface thereby indicating that groundwaters below this depth recharged prior to at least 1952 18o in the pore waters exhibit a distinctive regular shift with depth from water table values of 9 to 10 smow characteristic of present day precipitation to values between 14 and 17 at depths of 20 40 m which are characteristic of much cooler waters corrected 14c ages of the groundwater are greater than 8000 yr b p thereby suggesting that the groundwaters at depth entered these deposits during or after the formation of these deposits approximately 11 000 to 14 000 yr ago 18o 2h and cl concentration profiles were simulated with a one dimensional model for transport by advection and diffusion in a saturated porous medium reasonable agreement between the model and the field profiles was obtained with values of effective diffusion coefficients of 3 0 10 6 cm2 s for 18o 2h and cl and with groundwater velocities between 0 03 to 0 05 cm yr based on these results it is concluded that the pore water in these deposits is a mixture of late pleistocene and modern waters and that the distribution of 18c 2h and cl in these deposits is influenced predominantly by molecular diffusion apparently more so than by hydraulic flow

identification of mechanisms for landslide type initiation of debris flows the modelling of debris flow initiation in slopes is addressed in this paper first possible factors governing debris flow initiation are established then a coupled hydro mechanical model for deformable porous media with two pore fluids that is used to assess the problem of the debris flow initiation in slopes is briefly outlined various ways to identify failure and to approach the transition of the failed mass into a debris flow are discussed in the framework of small strain theory and elasto plastic behaviour a parametric study was carried out to evaluate the relative importance of the most commonly cited parameters that are assumed to influence debris flow initiation it was found that the slope angle is of minor importance in the development of slope instability under loading due to internal water supply transient behaviour was found to be decisive and some critical combinations of water supply over time yielded situations that were likely to encourage the onset of debris flow the significant role of permeability as a function of the degree of saturation in relation to the water supply is demonstrated the proposed three phase model is shown to be an adequate and promising way to address debris flow initiation

rainfall ground water flow and seasonal movement at minor creek landslide northwestern california physical interpretation of empirical relations simple ground water flow analyses can clarify complex empirical relations between rainfall and landslide motion here we present detailed data on rainfall ground water flow and repetitive seasonal motion that occurred from 1982 to 1985 at minor creek landslide in northwestern california and we interpret these data in the context of physically based theories we find that landslide motion is closely regulated by the direction and magnitude of near surface hydraulic gradients and by waves of pore pressure caused by intermittent rainfall diffusive propagation of pore pressure waves accompanies downward ground water flow along nearly vertical hydraulic gradients that exist in most of the landslide field data combined with a pore pressure diffusion analysis show that single rainstorms typically produce short period waves that attenuate before reaching the landslide base in contrast seasonal rainfall cycles produce long period waves that modify basal pore pressures but only after time lags that range from weeks to months such tune lags can depend on antecedent moisture storage and can explain variable delays between the onset of the wet season and seasonal landslide motion limit equilibrium analysis shows that when seasonal pressure waves reach the landslide base they establish a critical distribution of effective stress that delicately triggers landslide motion the critical effective stress balance is extremely sensitive to the direction and magnitude of hydraulic gradients although pervasively downward gradients instigate seasonal motion we infer from theory and limited data that ground water also may circulate locally in near surface cells the circulation can further reduce the landslide s frictional strength particularly in areas of nearly horizontal ground water flow that occur beneath steep faces of hummocks hummocky topography that results from slope instability may therefore cause ground water flow that perpetuates instability

assessment of active landslides using field electrical measurements abstract landslide characterization and hazard assessments require multidisciplinary approaches that connect geologic processes with geotechnical parameters preexisting landslide activity geology and geomorphology soil strength and hydrologic conditions are complex factors that affect landslide behavior often the connections among these factors are not made for hazard assessments forecasting or slope stability modeling therefore geophysical and geotechnical techniques for landslide investigations are typically assessed independently this study aims to bring together different techniques to develop a methodology that connects electrical measurements and shear strength a framework has been developed for using electrical resistivity measurements that will support and facilitate the prediction of shear strength within a slope in situ volumetric water content soil water potential suction and electrical conductivity were measured from two shallow colluvial landslides in kentucky repeated surface electrical resistivity survey measurements were used to characterize the failure zone and lithology and to compare with the in situ hydrologic measurements the data show that subsurface moisture conditions over time can be reflected in the inversions of repeated er surveys thus allowing electrical measurements and geotechnical parameters to be correlated this study demonstrates that electrical resistivity can be used as a tool for landslide monitoring and to assess shear strength these parameters are pertinent to investigating the stability of landslides that are often triggered or reactivated by rainfall

modeling stratigraphic architecture using small unmanned aerial vehicles and photogrammetry examples from the miocene east coast basin new zealand abstract the ability to view and characterize outcrops that are difficult to study from the ground is greatly improved by aerial investigation we describe the application of flying a small unmanned aerial vehicle uav to collect photographic data for modeling rock outcrops and creating detailed digital terrain models dtms which can be used for multi scale digital feature mapping in true three dimensional 3 d space georeferenced digital outcrops can complement field measurements as well as enhance classroom to field learning experiences for undergraduate education high resolution photographs acquired at various elevations and azimuths by a small uav are used to convert stratigraphic features to 3 d digital representations with spatial accuracy approaching 1 cm complex topography recorded in 2 d image sequences is rendered digitally in 3 d surface models using structure from motion sfm photogrammetry the resulting dtms are populated with the high resolution photographs for stratigraphic interpretation at the centimeter scale the method of imaging and modeling outcrops is demonstrated in the miocene east coast basin new zealand where steep coastal cliff exposures of continental slope deposits and extensive wave cut platform exposures of steeply dipping deep water basin deposits offer exceptional opportunities to investigate depositional processes and the resulting stratigraphic architecture our approach makes it possible to characterize deposits that are exposed in inaccessible 150 m high vertical sea cliffs and along 2000 m of wave cut platforms and to quantify their geometric variability results yield a spatial and temporal understanding of two depositional systems at a scale that was previously unattainable by conventional field techniques

field evidence of pore pressure diffusion in clayey soils prone to landsliding 1 the hydrologic behavior of shallow weathered soils commonly determines the propensity for slope failure here we use laboratory data and field data collected by an automated monitoring system to assess the character of pore water pressure responses in a natural clay slope subject to intermittent rainfall although we did not measure pore pressure distributions that triggered slope failure we obtained three years of field data that provided reliable and largely reproducible documentation of transient pore pressure responses at depths of tens of centimeters to a few meters below the ground surface moisture and pressure sensors recorded relatively fast transient responses to precipitation the speeds of pore pressure pulses advancing downward in the saturated zone were much larger than those of advective fronts driven by gravity and the amplitudes of the pulses attenuated with depth statistical assessment of 129 pressure head responses demonstrates that this behavior is consistent with predictions of a linear one dimensional pore pressure diffusion model however the model best simulates measurements if diffusivity is treated as a calibration parameter and if initial moisture conditions match model assumptions for regional assessment of slope stability the predictive accuracy of the linear diffusion model is limited by inherent uncertainties in defining the initial conditions and in assigning the values of hydraulic parameters

preliminary result from pore pressure monitoring on an unstable clay slope abstract we monitored positive pore water pressure in a clay slope in the apennines to investigate how rainfall influences the pore pressure distribution along the soil profile and consequently affects slope stability conditions data refers to the first season of monitoring activities august 2001 june 2002 the study site is located at the head of a complex landslide where incipient shallow failures are visible along the slope the preliminary analysis of pressure data allowed to point out consistent trends which manifested throughout 11 months during the cold and wet season saturation always extends close to the ground surface the presence of prefertial flow path in the sub surface can only explain anomalous response of some sensors or substantial differences between buried at similar depths

37cl 35cl variations in a diffusion controlled groundwater system abstract groundwaters in the low permeability quaternary glacial deposits of southwestern ontario commonly exhibit increasing cl concentrations with depth because these deposits were formed in a freshwater glacial environment and because cl is not derived from weathering of these deposits previous investigations hypothesized that upward diffusion of saline formation waters from the shallow bedrock caused this cl trend this hypothesis was tested by measuring 37 cl 35 cl ratios in the groundwaters from two typical sites and comparing the results with theoretically derived isotopic distributions produced by diffusion 37cl measurements expressed relative to standard mean ocean chloride smoc ranged from 0 8 to 2 2 and vertical profiles showed a gradual enrichment in 35cl relative to 37cl with increasing distance upward from the bedrock till interface 537cl distributions were simulated with a mathematical solute transport model incorporating the effects of kinetic isotopic partitioning a sensitivity analysis indicated that the model results were affected by the groundwater velocity the isotope enrichment factor and diffusion times agreement between the simulated and observed cl isotope profiles was obtained using a groundwater velocity of 0 an isotopic enrichment factor of 1 0012 and diffusion times ranging from 14 000 to 16 000 years based on these results we conclude that the isotopic enrichment in 35cl was caused by upward diffusion over a period of about 15 000 years this diffusion period is consistent with what is known about the quaternary history of the area

the permeability of natural soft clays part ii permeability characteristics reply the permeability characteristics of a number of intact natural soft clays from quebec the usa and sweden have been investigated in the laboratory the variation of permeability with void ratio is best represented in terms of a linear e vs lg k relation which is generally valid in the range of volumetric strains encountered in engineering practice the permeability at the in situ void ratio is shown to be a complex function of such parameters as the void ratio the clay fraction the plasticity index and the fabric of the clay permeability anisotropy is negligible in marine clays the e vs lg k relationships of the various clays tested are well ordered in terms of an empirical parameter ip clay fraction irrespective of the geological origin of the clay the slope of the e vs lg k relationship referred to as permeability change index ck is simply related to the initial void ratio by ck 0 5eo keywords permeability clays laboratory tests permeability anisotropy permeability void ratio re

extensional deformation across an active margin relations with subsidence uplift and rotations the hikurangi subduction new zealand on the basis of field studies in the forearc domain of the hikurangi subduction margin in the eastern north island of new zealand we analyze the evolution of the subduction since its onset 25 myr ago analyses of brittle deformation within this forearc domain have revealed evidence of extensional deformation contemporaneous with the subduction of the pacific plate beneath the north island the type and origin of extensional deformation during the development of the active margin are discussed the problem is crucial because this forearc domain was previously considered as having undergone almost continuous compression during the late cenozoic two distinct events of late cenozoic extensional deformation are identified the youngest one is quaternary in age it affects limited areas where important uplift prevails the orientation of extensional paleostress axes is perpendicular to that of uplift axes hence consistent with the classical hypothesis of gravitational collapse affecting the upper part of the margin of particular interest is the older extensional event middle late miocene in age it affected most of the forearc domain during a long time span that was also characterized by widespread margin subsidence some structures attributed to this event are syndepositional including rollover structures and there are mainly high angle normal faults that affect not only the miocene sediments but also the pre miocene basement the orientations of paleostress axes obtained by inversion of fault data sets are multiple after corrections taking into account the rotational history of the margin during the late cenozoic they are found to be generally consistent with two major trends because these extensional structures developed throughout a long period of the margin subsidence it is proposed that they reflect the process of tectonic erosion that affected the hikurangi active margin during the middle and late miocene between about 15 and 5 myr ago

structure from motion photogrammetry a low cost effective tool for geoscience applications abstract high resolution topographic surveying is traditionally associated with high capital and logistical costs so that data acquisition is often passed on to specialist third party organisations the high costs of data collection are for many applications in the earth sciences exacerbated by the remoteness and inaccessibility of many field sites rendering cheaper more portable surveying platforms i e terrestrial laser scanning or gps impractical this paper outlines a revolutionary low cost user friendly photogrammetric technique for obtaining high resolution datasets at a range of scales termed structure from motion sfm traditional softcopy photogrammetric methods require the 3 d location and pose of the camera s or the 3 d location of ground control points to be known to facilitate scene triangulation and reconstruction in contrast the sfm method solves the camera pose and scene geometry simultaneously and automatically using a highly redundant bundle adjustment based on matching features in multiple overlapping offset images a comprehensive introduction to the technique is presented followed by an outline of the methods used to create high resolution digital elevation models dems from extensive photosets obtained using a consumer grade digital camera as an initial appraisal of the technique an sfm derived dem is compared directly with a similar model obtained using terrestrial laser scanning this intercomparison reveals that decimetre scale vertical accuracy can be achieved using sfm even for sites with complex topography and a range of land covers example applications of sfm are presented for three contrasting landforms across a range of scales including an exposed rocky coastal cliff a breached moraine dam complex and a glacially sculpted bedrock ridge the sfm technique represents a major advancement in the field of photogrammetry for geoscience applications our results and experiences indicate sfm is an inexpensive effective and flexible approach to capturing complex topography

the role of woody vegetation in stabilizing slopes in the cincinnati area ohio tree roots markedly stabilize colluvium on steep hillsides in the cincinnati area ohio according to detailed analysis of a landslide complex on the south side of rapid run creek a tributary of the ohio river the shear surface of the slide developed near the interface between bouldery silty clay colluvium and underlying calcareous ordovician shale and it broke woody roots that penetrated through the colluvium and into the underlying bedrock measurements of positions sizes and tensile strengths of the roots indicate that the average shear strength contributed by the roots was about 5 7 kn m 2 of the shear surface the average strength contributed by residual friction of the soil was about 0 7 kn m 2 the tree roots increased the factor of safety against sliding nine fold root strength allows forested colluvium mantled hillslopes in the cincinnati area to resist sliding at slope angles as high as 35 whereas similar slopes devoid of trees are subject to sliding at slope angles of 12 to 14 the contribution of tree roots to slope stability should be evaluated before removal of trees for development of hillsides

geomorphology and vegetation on hillslopes interactions dependencies and feedback loops article i nfo the linkages between vegetation and hillslope geomorphology have been the subject of serious study for years but traditionally ecologists and geomorphologists have viewed these interactions as unidirectional on the one hand botanists and landscape ecologists have examined the effects of hillslope features processes and materials on vegetation structure composition and dynamics focus has been placed on the effects of topography elevation slope angle slope aspect edaphic factors rock type and geomorphic disturbance mass movement snow avalanches land surface erosion on the other hand geomorphologists have traditionally treated vegetation as an independent variable that affects landforms and sediment routing at limited spatial temporal scales hillslope vegetation and landforms however co evolve one key is to understand the role of time disturbances and feedbacks that link vegetation and geomorphology on hillslopes the effects of vegetation on mass movement and landscape evolution are being studied in new ways many regional studies claim that vegetation becomes less relevant as one moves to larger and larger watershed scales but ecoregion analysis offers a contrasting view whereas these efforts have produced vehicles of understanding that are simple ordered unified and harmonious they often do not reflect the complexity that leads to multiple possible outcomes place dependent results recent perspectives focus on the two way interplay between vegetation and hillslope geomorphology where establishing cause and effect linkages is made difficult by confounding factors spatial temporal scale location convergence divergence nonlinearity thresholds feedbacks vegetation and geomorphology interactions are controlled by a combination of global factors independent of time and place and the local environmental history continued refinement of fine scale deterministic models should be encouraged but the ability to translate these results to larger scales needs to be explored at large scales future research especially those with predictive modeling as the goal should concentrate on how to increase the generality of concepts and models and should seek to reduce the number of variables and factors considered

review of drones photogrammetry and emerging sensor technology for the study of dykes best practises and future potential abstract dykes play a major role in transporting magma through the crust to subsurface storage reservoirs or eruption sites at the surface the geometry connectivity and internal textures of dykes preserve an important record of dyke emplacement linkage and magma flow dynamics unravelling these facets of dyke evolution is critical to interpreting signals of magma migration in active volcanoes as well as tectonic processes including crust formation and continental break up during hazard assessment unfortunately our ability to develop new insights is limited by the continuity of high precision data that can be extracted from the field the emergence of unmanned aerial vehicles uavs a k a drones photogrammetry and other sensor techniques are set to greatly improve our field capabilities by collecting data at higher density and with greater precision here we present a workflow emphasising best practise in uav survey design the construction of photogrammetric models and standardised reporting of those models emphasis is given to the factors that should be considered in order to resolve the geological features of interest in any study e g wall rock fractures chilled margins magmatic breccias dyke apertures etc a point to raster technique is documented that measures spatial error in the rasters that are derived from photogrammetric models e g orthomosaics and digital elevation models using three case studies we show how dyke swarms can be mapped accurately over areas approaching 1 km2 at sub centimetre resolution the data illustrate how questions about dyke induced deformation host rock controls on segmentation and aperture variation may be addressed and we present a method for the high density high precision measurement of dyke apertures in 3d we also review semi automated mapping tools and emerging uav sensing techniques including hyperspectral and aeromagnetic sensors and the potentially important contributions they will make to the study of intrusive systems and volcanology more broadly

unsaturated and saturated flow through a thin porous layer on a hillslope the subsurface stormflow in a layer of porous earth overlying an impervious hill is investigated in the case when the thickness of the layer is small compared to a typical hill dimension if the infiltration rate at the surface is low and varies slowly with time the head is approximately constant along normals to the hillslope and the flow in both the saturated and unsaturated regions is described by a simple kinematic wave equation solutions of this equation describe the spatial and temporal development of the water table as well as the flow in the saturated and unsaturated regions a numerical example is given