temporal correlation between seismic moment and injection volume for an induced earthquake sequence in central oklahoma the rapidly increased earthquake rate in the central united states has been linked with wastewater injection while the overall understanding appears clear at large scales the interaction between injection and faulting at smaller scales within individual sequences is still not clear for an earthquake sequence in central oklahoma we conduct finer scale analysis of the spatiotemporal evolution of seismicity and pore pressure modeling the pore pressure modeling suggests that nearby wells show much stronger correlation with earthquake sequence evolution detailed temporal analysis found correlation between earthquake rate seismic moment and injection rates from wells in close proximity however the observed maximum magnitude mmax is about one order of magnitude smaller than expected based on a theoretical relationship between mmax and cumulative volume this discrepancy may point toward additional parameters such as fault size and stress which influence mmax the lower mmax is consistent with the truncated gutenberg richter distribution observed from matched filter detected catalog overall the detailed observations suggest that it is possible to resolve relationships between individual disposal wells and induced earthquake sequences

the detection of low magnitude seismic events using array based waveform correlation summary it has long been accepted that occurrences of a known signal are most effectively detected by cross correlating the incoming data stream with a waveform template such matched signal detectors have received very little attention in the field of detection seismology because there are relatively few instances in which the form of an anticipated seismic signal is known a priori repeating events in highly confined geographical regions have been observed to produce very similar waveforms and good signals from events at a given site can be exploited to detect subsequent co located events at lower magnitudes than would be possible using traditional power detectors even greater improvement in signal detectability can be achieved using seismic arrays running correlation coefficients from single sensors can be stacked over an array or network to result in a network correlation coefficient displaying a significant array gain if two events are co located the time separating the corresponding patterns in the wave train as indicated by the cross correlation function is identical for all seismic stations and this property means that the correlation coefficient traces are coherent even when the waveforms are not we illustrate the power of array based waveform correlation using the 1997 august 16 kara sea event the weak event that occurred 4 hr after the main event was barely detected using an sta lta detector on the spits array but is readily detected by signal matching on a single channel the main event was also recorded by the far more distant norsar array but no conventional detection can be made for the second event a clear detection is however made when the correlation coefficient traces are beamformed over all sensors of the array we estimate the reduction in detection threshold of a test signal on a regional seismic array using waveform correlation by scaling down a master signal and immersing it into seismic noise we show that for this case waveform correlation using a single channel detects signals of approximately 0 7 orders of magnitude lower than is possible using an sta lta detector on the array beam waveform matching on the full array provides an additional improvement of approximately 0 4 magnitude units we describe a case study in which small seismic events at the barentsburg coal mine on spitsbergen were detected using the signals from a major rockburst as master waveforms many spurious triggers occurred in this study whereby short sections of signal exhibited coincidental similarity with unrelated incoming wave fronts we demonstrate how such false alarms can almost always be identified and screened out automatically by performing frequency wavenumber analysis upon the set of individual correlation coefficient traces

bed load grain velocities and sediment transport rates theoretical consideration of the dynamics of bed load sediment transport leads to expressions for bed grain velocity and sediment transport rate as respectively ub a u u c and ib a tan u u c 0 c agreeing in form with many previous analyses the grain velocity equation agrees well with all experimentally determined velocities of single grains moving over fixed rough beds if a is allowed to vary with bed roughness and saltation height values of u c for such overriding grains are substantially less than normally accepted values the sediment transport rate equation predicts plane bed experimental data well over five orders of magnitude of ib values of a tan increase significantly from lower to upper stage plane beds due to an increase in a with suspended sediment concentration but also due to a decrease in tan with increasing transport stage and grain size as predicted by bagnold

mathematical modeling of graded river profiles numerical modeling of the longitudinal profiles of rivers at grade is accomplished using the basic equations of open channel flow sediment transport equations and empirical relations for downstream variation in flow discharge sediment discharge sediment caliber and channel width only in some cases are the computed stream profiles fit exactly by any one of the commonly supported mathematical function analogs to graded profile form exponential logarithmic or power function but in most cases any of these functions can provide a fit with a degree of error smaller than would be noted in treating field data profiles dominated by spatial change in fluid and sediment discharge are distinctly power functions while profiles dominated by sediment size reduction are not necessarily exponential in form other important controls on profile shape are the degree of downstream width change in response to increasing discharge and the general range of sediment size a dynamic model of a river s approach to grade

small channels their experimental formation nature and significance the manner in which small channels are generated from plane beds beneath sheet flows has been experimentally elucidated on plane erodible sand beds the transition from thin supercritical sheet flows to the channelled condition was studied over ranges of discharge slope and temperature secondary flow of the second kind its action facilitated by steep vertical velocity gradients in the primary flows caused sheet flow instability along junctions between neighbouring secondary cells both either raised or lowered elements of the primary flow in the latter case fast surface water was lowered to the bed causing relatively intense local longitudinal scour dislodged grains were moved divergently to either side leaving straight central trenches development of positive feedback between cells and trenches led to rapid enlargement of the latter and concomitant growth of paired levees the resulting structures protochannels were themselves ephemeral developing two types of instability associated with secondary flow of the first kind firstly small deviations from bilateral symmetry were enhanced causing evolution into meandering channels secondly headcutting led to multiple tributary development and at resulting confluences the action of strong pairs of secondary cells led to the development of braiding channels because they are shortlived protochannels are but rarely seen in nature their seeding is markedly temperature sensitive reflecting their frictional origin the erosive power of shallow overland flow largely depends on flow energy concentration by secondary flow firstly into channels then within the channels themselves suppression of secondary flow as by intense raindrop bombardment can stabilize sheet flows in deeper water the effects of secondary flow appear relatively less dramatic however even if such motion is weak bedload divergence from attachment lines can favour entrainment locally and thus affect bed geometry analogy between our results and river behaviour appears close and on continental shelves where water must often flow as sheets structures resembling giant protochannels evidently persist

reply to the discussion by chapuis weber and duhaime on intrinsic permeability of materials ranging from sand to rock fill using natural air convection tests 1 1appears in the canadian geotechnical journal 49 11 1319 1322 doi 10 1139 t2012 073 the authors thank the discussers for their interest in this paper and for expanding and updating a previous discussion on representative elementary volume chapuis et al 2006 we also appreciate the opportunity to clarify some issues of our experimental method and to introduce a recent updated analysis of our experimental data the experimental determination of permeability of rock fill materials represents a challenging task it was shown in the paper that hydraulic permeability tests were mostly inappropriate because turbulent flow dominates even under very low hydraulic gradients and darcy s law is thus not valid natural air convection testing within a heat transfer cell was therefore selected to overcome this issue the intrinsic permeability was obtained using the well established analytical solution to natural convection in a square enclosure of schubert and straus 1979 the study clearly showed that the inferred intrinsic permeability values were well within the narrow bounds formed by the extrapolation of two predictive equations previously established to estimate the permeability of sands the discussers acknowledged that these were amongst the best equations to predict permeabilities of nonplastic materials these results are excellent given the somewhat untypical and innovative experimental testing method and given that the predicting equations had to be extrapolated 3 to 5 orders of magnitude higher than the typical permeability range of sands for which these equations were validated for example predictions from chapuis 2004 equation were on average only 2 5 times lower than the inferred permeability values the discussers focused on specimen representativeness and support their thoughts with studies on arrangements of spheres arrangements known to have marked sidewall effects this is definitely not representative of our study the specimens in the paper were made of randomly shaped natural cobbles that were hand placed one by one into the heat transfer cell see fig 5 in companion paper by fillion et al 2011 this allowed obtaining homogeneous specimens for example a particle placed on one edge of the cell had its flattest side facing out greatly reducing sidewall effects horizontal sand blankets were also put on the top and bottom of the heat transfer cell further eliminating sidewall effect and ensuring optimized thermal contact with the heat transfer systems bias due to specimen preparation can thus be considered as insignificant in a recent study dhyser et al 2012 it was demonstrated that the analytical solution to natural convection induced a slight overestimation of permeability values the analytical solution used at the time of the study was developed for a perfectly insulated and impervious square enclosure the heat transfer cell was air tight but did not meet the perfectly insulated boundary condition of the schubert and straus 1979 solution in the new study a numerical solution to natural convection heat and mass transfer within a domain representing the experimental cell was developed this numerical solution was used to re evaluate the permeability values from the original test results it turns out that the newly inferred permeability values are now very close to the estimated ones using chapuis 2004 equation as shown in fig r1 the new values are now within the 0 5 2 times precision range found by chapuis 2004 it can therefore be concluded that the original bias between the experimentally inferred permeability values and the predicted ones was due mostly to a preliminary assessment using an analytical solution to convection heat transfer a more accurate numerical solution adapted to the experimental heat

empirical relations for the sediment transport capacity of interrill flow experiments were carried out in order to measure the sediment transport capacity of interrill flow with and without rainfall and to relate the transport capacity to selected hydraulic parameters such as effective stream power and shear velocity different sediments were used in order to study the effect of grain size the proposed relationships show considerable variations with grain size and there is only a minor effect of rainfall on the transport capacity which also seems to be grain size dependent the proposed relationships can be used to predict sediment transport capacity of interrill flow and can therefore contribute to the development of physically based erosion models

comparison of rill flow velocity regimes between developing and stationary rills abstract flow velocity is fundamental in calculating related parameters of physical soil erosion models it has been well known that rill flow velocity varies with developing rill form which complicates and impedes the development of soil erosion models in filed rainfall erosion frequently occurs with pre existing rills not damaged by tillage practices however the rill flow velocity in this case has received little attention in this study we investigated rill flow velocity regimes for both developing and stationary rills using 5 m length plots in the laboratory the experiments included two consecutive rainfalls which had similar runoff rate the first rainfall had an intensity of 90 mm h 1 which generated well developed rills the second had an intensity of 60 mm h 1 and did not damage the rills formed by the first rainfall the results show that for a developing rill rill flow velocity is higher in the lower slope than that in the upper slope and rill flow velocity in the lower slope fluctuates much more over time as a result of the variation of rill morphology following rill development with rill development the rill flow velocity of the lower slope decreased responding to the stabilizing rill channel and exhibited a similar trend to that in upper slope for a stationary rill the rill flow velocities at both sections varied little over time demonstrating that rill flow velocity is primarily influenced by rill morphology hence the results suggested that the strength of fluctuation in rill flow velocity could be used to characterize the instantaneous intensity of soil erosion and active level of rill development the channel of the stationary rill simply acted as transport pathways of sediment supplied by inter rill erosion the physical models of soil erosion should take into account the micro topography on land surface related to the antecedently formed rills

characterization of the rill geometry over straight hillslopes through spatial scales abstract experimental evidence is presented which shows that there exists a spatial scale over which ergodic assumptions are applicable for rilled hillslope surfaces the property of expected spatial rill density esrd is defined and this property is shown to stabilize after the averaging interval is more than 20 ft over the hillslope the rilled hillslope geometry may be readily quantified in terms of this easily measurable quantity the rill geometry has a significant influence on the surface distribution of overland flow and sediment transport an analysis of the spatial scales suggests that a continuum representation may be utilized in modeling these hydrodynamic flow phenomena for a complete characterization of the rilled hillslope geometry the distributions of the rill widths and rill depths at various locations along the hillslope have been presented these preliminary results show that the mean rill widths the mean rill depths and the esrd increase with increasing slope lengths the distributions of the rill widths and rill depths suggest that these quantities may be modeled by truncated gaussian or gamma distributions at different spatial locations the rill geometry properties may be related to hydrologic and geomorphologic properties of the hillslope it is suggested that the esrd is a better descriptor of the rill geometry on the hillslope than the rill density because of the wide variations exhibited by the distributions of the rill widths

soil erodibility and processes of water erosion on hillslope abstract the importance of the inherent resistance of soil to erosional processes or soil erodibility is generally recognized in hillslope and fluvial geomorphology but the full implications of the dynamic soil properties that affect erodibility are seldom considered in canada a wide spectrum of soils and erosional processes has stimulated much research related to soil erodibility this paper aims to place this work in an international framework of research on water erosion processes and to identify critical emerging research questions it focuses particularly on experimental research on rill and interrill erosion using simulated rainfall and recently developed techniques that provide data at appropriate temporal and spatial scales essential for event based soil erosion prediction results show that many components of erosional response such as partitioning between rill and interrill or surface and subsurface processes threshold hydraulic conditions for rill incision rill network configuration and hillslope sediment delivery are strongly affected by spatially variable and temporally dynamic soil properties this agrees with other recent studies but contrasts markedly with long held concepts of soil credibility as an essentially constant property for any soil type properties that determine erodibility such as soil aggregation and shear strength are strongly affected by climatic factors such as rainfall distribution and frost action and show systematic seasonal variation they can also change significantly over much shorter time scales with subtle variations in soil water conditions organic composition microbiological activity age hardening and the structural effect of applied stresses property changes between and during rainstorms can dramatically affect the incidence and intensity of rill and interrill erosion and therefore both short and long term hillslope erosional response similar property changes linked to climatic conditions may also significantly influence the stability and resilience of plant species and vegetation systems full understanding of such changes is essential if current event based soil erosion models such as wepp and eurosem are to attain their full potential predictive precision the complexity of the interacting processes involved may however ultimately make stochastic modelling more effective than physically based modelling in predicting hillslope response to erodibility dynamics

predicting the saturated hydraulic conductivity of sand and gravel using effective diameter and void ratio this paper assesses methods to predict the saturated hydraulic conductivity k of clean sand and gravel currently in engineering the most widely used predictive methods are those of hazen and t

extraction of potential debris source areas by logistic regression technique a case study from barla besparmak and kapi mountains nw taurids turkey debris flow is one of the most destructive mass movements sometimes regional debris flow susceptibility or hazard assessments can be more difficult than the other mass movements determination of debris accumulation zones and debris source areas which is one of the most crucial stages in debris flow investigations can be too difficult because of morphological restrictions the main goal of the present study is to extract debris source areas by logistic regression analyses based on the data from the slopes of the barla besparmak and kapi mountains in the sw part of the taurids mountain belt of turkey where formation of debris material are clearly evident and common in this study in order to achieve this goal extensive field observations to identify the areal extent of debris source areas and debris material air photo studies to determine the debris source areas and also desk studies including geographical information system gis applications and statistical assessments were performed to justify the training data used in logistic regression analyses as representative a random sampling procedure was applied by using the results of the logistic regression analysis the debris source area probability map of the region is produced however according to the field experiences of the authors the produced map yielded over predicted results the main source of the over prediction is structural relation between the bedding planes and slope aspects on the basis of the field observations for the generation of debris the dip of the bedding planes must be taken into consideration regarding the slope face in order to eliminate this problem in this study an approach has been developed using probability distribution of the aspect values with the application of structural adjustment the final adjusted debris source area probability map is obtained for the study area the field observations revealed that the actual debris source areas in the field coincide with the areas having high probability values on this final map

precise relative earthquake magnitudes from cross correlation abstract we present a method to estimate precise relative magnitudes using cross correlation of seismic waveforms our method incorporates the intercorrelation of all events in a group of earthquakes as opposed to individual event pairings relative to a reference event this method works well when a reliable reference event does not exist we illustrate the method using vertical strike slip earthquakes located in the northeast pacific and panama fracture zone regions our results are generally consistent with the global centroid moment tensor catalog which we use to establish a baseline for the relative event sizes online material supplementary description and formulation of uncertainty and tables of relative magnitudes

sand bentonite liners predicting permeability from laboratory tests soil bentonite mixes are frequently used as impervious blankets in waste disposal projects numerous results of laboratory permeability tests are presented for sands containing up to 33 bentonite these results seem difficult to analyze because different testing methods have been used in which it is not easy to control certain parameters such as hydration period degree of saturation and swelling under low confining pressure hydraulic conductivity however can be obtained by using empirical equations that take into account the bentonite content porosity and degree of saturation of the sand alone when tested at its optimum modified proctor value in a permeameter this preliminary evaluation helps to select the soil to be tested then the laboratory test results can be used to predict the in situ hydraulic performance after due consideration of the variabilities in natural sand and bentonite content key words liner soil bentonite permeability laboratory field

a sediment transport model for incision of gullies on steep topography 1 we have conducted surveys of gullies that developed in a small steep watershed in the idaho batholith after a severe wildfire followed by intense precipitation we measured gully length and cross sections to estimate the volumes of sediment loss due to gully formation these volume estimates are assumed to provide an estimate of sediment transport capacity at each survey cross section from the single gully forming thunderstorm sediment transport models commonly relate transport capacity to overland flow shear stress which is related to runoff rate slope and drainage area we have estimated the runoff rate and duration associated with the gully forming event and used the sediment volume measurements to calibrate a general physically based sediment transport equation in this steep high shear stress environment we find that a shear stress exponent of 3 corresponding to drainage area and slope exponents of m 2 1 and n 2 25 match our data this shear stress exponent of 3 is approximately 2 times higher than those for bed load transport in alluvial rivers but is in the range of shear stress exponents derived from flume experiments on steep slopes and with total load equations the concavity index of the gully profiles obtained theoretically from the area and slope exponents of the sediment transport equation c m 1 n agrees well with the observed profile concavity of the gullies our results although preliminary because of the uncertainty associated with the sediment volume estimates suggest that for steep hillslopes such as those in our study area a greater nonlinearity in the sediment transport function exists than that assumed in some existing hillslope erosion models which calculate sediment transport capacity using the bed load equations developed for rivers

tests of selected sediment transport formulas eleven existing sediment transport formulas were tested against the field data measured at two united states geological survey usgs gauging stations along the sacramento river in california whose bed material sizes are classified as those ranging from fine sand to coarse gravel they include the ackers white einstein brown engelund fredsoe engelund hansen inglis lacey karim meyer peter and mueller rijin schoklitsch toffaleti and yang formulas general flow and sediment input variables required by each transport function as well as dependent variables are summarized and detailed and measured hydraulic and sediment quantities including bed material size distributions are presented the computed sediment discharges are tabulated for comparison and are directly compared against the measured suspended sediment discharges the computed values however are found to deviate significantly from the measured values except for a very few cases the test results clearly demonstrate how difficult a ta

landslide susceptibility assessment in lianhua county china a comparison between a random forest data mining technique and bivariate and multivariate statistical models abstract landslides are an important natural hazard that causes a great amount of damage around the world every year especially during the rainy season the lianhua area is located in the middle of china s southern mountainous area west of jiangxi province and is known to be an area prone to landslides the aim of this study was to evaluate and compare landslide susceptibility maps produced using the random forest rf data mining technique with those produced by bivariate evidential belief function and frequency ratio and multivariate logistic regression statistical models for lianhua county china first a landslide inventory map was prepared using aerial photograph interpretation satellite images and extensive field surveys in total 163 landslide events were recognized in the study area with 114 landslides 70 used for training and 49 landslides 30 used for validation next the landslide conditioning factors including the slope angle altitude slope aspect topographic wetness index twi slope length ls plan curvature profile curvature distance to rivers distance to faults distance to roads annual precipitation land use normalized difference vegetation index ndvi and lithology were derived from the spatial database finally the landslide susceptibility maps of lianhua county were generated in arcgis 10 1 based on the random forest rf evidential belief function ebf frequency ratio fr and logistic regression lr approaches and were validated using a receiver operating characteristic roc curve the roc plot assessment results showed that for landslide susceptibility maps produced using the ebf fr lr and rf models the area under the curve auc values were 0 8122 0 8134 0 7751 and 0 7172 respectively therefore we can conclude that all four models have an auc of more than 0 70 and can be used in landslide susceptibility mapping in the study area meanwhile the ebf and fr models had the best performance for lianhua county china thus the resultant susceptibility maps will be useful for land use planning and hazard mitigation aims

unit stream power equation for gravel the basic assumptions used in the derivation of bedload or gravel transport equations are reviewed and examined to determine their validities laboratory data indicate that unit stream power is mor

sediment transport and unit stream power function basic fluid mechanics and turbulence theories are applied to show that suspended sediment concentration at a given depth of an open channel flow is a function of the turbulence energy production rate at that depth depth averaged suspended sediment concentration can be obtained by integrating a function of the turbulence energy production rate over the depth of flow which in turn is a function of unit stream power total sediment concentration can also be expressed as a function of unit stream power following the foresaid and a procedure similar to that proposed by einstein comparisons of seven total load equations indicate that equations derived from the concept that the rate of sediment transport should be related to the rate of energy dissipation of the flow are more accurate than other equations for both laboratory flumes and natural rivers

a contour based topographic model for hydrological and ecological applications a digital model for discretizing three dimensional terrain into small irregularly shaped polygons or elements based on contour lines and their orthogonals is described from this subdivision the model estimates a number of topographic attributes for each element including the total upslope contributing area element area slope and aspect this form of discretization of a catchment produces natural units for problems involving water flow as either a surface or subsurface flow phenomenon the model therefore has wide potential application for representing the three dimensionality of natural terrain and water flow processes in the fields of hydrology sedimentology and geomorphology three example applications are presented and discussed they are the prediction of zones of surface saturation the prediction of the distribution of potential daily solar radiation and the prediction of zones of erosion and deposition in a catchment

erosion rates in badland areas recorded by collectors erosion pins and profilometer techniques ebro basin ne spain abstract in badland areas of the ebro basin in a semiarid climate two erosion plots 257 m2 5 slope and 128 m2 23 slope on exposed tertiary clays were monitored over two years nov 1991 nov 1993 this material is characterized by high sodium absorption ratios which lead to high soil dispersivity the dominant erosion processes in both plots are rilling and sheet erosion rainfall intensity was recorded at a weather station connected to a data logger sediment production for single events was collected in tanks and ground lowering was measured every six months by erosion pins and microtopographic profile gauge techniques significant runoff was produced only by rainfall events above 5 mm another threshold at 20 mm rain was noted for rainfalls higher than 20 mm the 23 slope plot shows a greater runoff response than the 5 one rainfall events exceeding this threshold showed a higher sediment production for the steeper slope in the relationship between precipitation and sediment concentration an envelope curve can be drawn indicating that any rainfall event of a given amount and intensity has a maximum sediment concentration which we speculate to be a function of the runoff sediment transport capacity runoff response and sediment yield in the studied plots are controlled by the rainfall and soil characteristics and their seasonal variations in both plots the erosion pins show that erosion rates in rill areas are 25 50 higher than in the interrill areas sediment yield recorded by collector devices was higher than the rates measured by erosion pins the erosion rates based on rill cross sections by profilometers were higher than the ones recorded by collectors

precise relative earthquake location using surface waves 1 earthquake locations provide a fundamental tool for seismological investigations while dense seismic networks can provide robust locations accuracy and precision of these locations suffer outside dense networks this is particularly true in offshore areas where location analysis relies heavily on distant seismic observations we present a method for estimating precise relative seismic source epicentroid locations using surface waves several reasons including lower velocities and strength of the signal at distance make use of surface waves for event location appealing we focus on the panama fracture zone region and relocate 81 strike slip earthquakes to produce tectonically consistent epicentroid locations the resulting pattern of earthquakes more clearly delineates recently active regional structures than original body wave locations the mean shift between the us geological survey national earthquake information center epicenter and our epicentroids is about 14 km the median is about 11 km and typical origin time changes are generally less than 2 s we find that north of 6 5 n the plate boundary motion is split across two roughly north south striking structures the panama and balboa fracture zones for the last 36 years slip along these two structures roughly matches slip along the panama fracture zone to the south from 4 5 n to 6 25 n but the balboa fracture zone has roughly three times the moment than the northern panama fracture zone our analyses show that observed rayleigh wave signal to noise ratios for moderate to large shallow earthquakes are suitable for applying the procedure and that rayleigh wave observations form a self consistent set of constraints on the relative location of earthquake centroids

laboratory permeability tests on sand influence of the compaction method on anisotropy new laboratory results are presented on how densification influences the hydraulic anisotropy of a sand results are given for two compaction modes tests were performed at different densities in order to derive the curves kv e and kh e the samples were statically compacted in the first series and dynamically compacted in the second series the ratio rk kh kv is different for the two series it is higher than 1 for static compaction and lower than 1 for dynamic compaction thus the anisotropy ratio of granular soils can take several values for the same void ratio depending on the preparation mode even if the anisotropy ratios differ the first invariant of the hydraulic conductivity tensor 11k is found to be a function of e only for this sand regardless of the densification mode the evolution of an adimensional anisotropy index i1k kv versus a density index ie is compared for the sand and a dispersed clay the evolutions are nearly identical which means that the hydraulic anisotropy of na

the 2000 r m hardy lecture full scale hydraulic performance of soilbentonite and compacted clay liners the results of laboratory and in situ permeability tests can be used to predict the total leakage rate of a soil bentonite or clay liner this prediction however ignores the large influence that minor defects may have on the total leakage in quebec hundreds of municipal wastewater ponds have been filled with water to measure their total leakage rate before approval the design criteria and the equations to be used for the full scale performance test are briefly reviewed with their capacities to detect hydraulic deficiencies several case histories are presented to illustrate various problems excessive leakage of a stable soil bentonite mix washing of bentonite in a soil bentonite mix internal erosion of a natural clay liner through an inadequate sand filter and effects of freezing on the total leakage of a clay liner key words liner clay bentonite permeability performance full scale test

a distributed slope stability model for steep forested basins a distributed physically based slope stability model dslam based on an infinite slope model a kinematic wave groundwater model and a continuous change vegetation root strength model is presented it is integrated with a contour line based topographic analysis and a geographic information system gis for spatial data extraction and display the model can be run with either individual rainfall events or long term sequences of storms these inputs can be either actual storm records or synthesized random events based on monte carlo simulation the model is designed to analyze rapid shallow landslides and the spatial distribution of safety factor fs in steep forested areas it can investigate the slope stability problem in both temporal and spatial dimensions for example the impact of timber harvesting on slope stability either at a given time or through an extended management period the probability of landslide occurrence for a given year and the delivery of landslide sediments to headwater streams the dslam model was applied in a steep forested drainage of cedar creek in the oregon coast ranges using actual spatial patterns of timber harvesting and measured rainfall during a major storm which triggered widespread landslides in that area in 1975 simulated volume and number of failures were 733 m3 and 4 respectively these values agreed closely with field measurements following the 1975 storm however the effect of parameter uncertainty may complicate this comparison for example when soil cohesion values of 2 0 and 3 0 kpa were used the failure volume changed by factors of 2 04 and 0 41 respectively compared with the average condition of 2 5 kpa used in the simulation for soil depths 30 higher and lower than the standard condition the failure volume changed by factors of 2 0 and 0 27 respectively when maximum root cohesion changed from 12 5 kpa average condition to 10 kpa the failure volume increased 1 73 fold for the case of 15 kpa the failure volume changed by a factor of 0 55 the simulated failures caused by the storm were mostly in hollows the simulations show that the spatial distribution of fs is controlled mainly by topography and timber harvesting patterns and is greatly affected by groundwater flow patterns during major rainstorms most areas with fs 3 0 corresponded with the distribution of blocks clear cut in 1968 and all elements with fs 2 0 were in areas clear cut in 1968 areas with low fs 1 0 1 6 expanded dramatically during the rainstorm and decreased at a slow rate after the storm factors of safety in hollows declined sharply during the storm

rupture processes of the 2013 2014 minab earthquake sequence iran we constrain epicentroid locations magnitudes and depths of moderate magnitude earthquakes in the 2013 2014 minab sequence using surface wave cross correlations surfacewave spectra and teleseismic body wave modelling we estimate precise relative locations of 54 mw 3 8 earthquakes using 48 409 teleseismic intermediate period rayleigh and lovewave cross correlation measurements to reduce significant regional biases in our relative locations we shift the relative locations to align the mw 6 2 main shock centroid to a location derived from an independent insar fault model our relocations suggest that the events lie along a roughly east west trend that is consistent with the faulting geometry in the gcmt catalogue the results support previous studies that suggest the sequence consists of leftlateral strain release but better defines the main shock fault length and shows that most of the mw 5 0 aftershocks occurred on one or two similarly oriented structures we also show that aftershock activity migrated westwards along strike away from the main shock suggesting that coulomb stress transfer played a role in the fault failure we estimate the magnitudes of the relocated events using surface wave cross correlation amplitudes and find good agreement with the gcmt moment magnitudes for the larger events and underestimation of small event size by catalogue ms in addition to clarifying details of the minab sequence the results demonstrate that even in tectonically complex regions relative relocation using teleseismic surface waves greatly improves the precision of relative earthquake epicentroid locations and can facilitate detailed tectonic analyses of remote earthquake sequences

a method for calibration of the local magnitude scale based on relative spectral amplitudes and application to the san juan bautista california area we develop and use a spectral empirical green s function approach to estimate the relative source amplitudes of earthquakes near san juan bautista california we isolate the source amplitudes from path effects by comparing the recorded spectra of pairs of events with similar location and focal mechanism without computing the path effect with this method we estimate the relative moments of 1600 m 1 5 4 local earthquakes and we use these moments to recalibrate the duration magnitude scale in this region the estimated moments of these small earthquakes increase with catalog magnitude m d roughly proportionally to 101 1 m d slightly more slowly than a moment magnitude scaling of 101 5 m w this more accurate magnitude scaling can be used in analyses of the local earthquakes such as comparisons between the seismic moments and geodetic observations electronic supplement 1 additional description and figures showing estimated source amplitudes obtained with different parameters and observed amplitudes of some earthquakes with large misfits 1 http www bssaonline org lookup suppl doi 10 1785 0120160141 dc1

analytical method for determining rill detachment rate of purple soil as compared with that of loess soil abstract rill detachment is an important process in rill erosion the rill detachment rate is the fundamental basis for determination of the parameters of a rill erosion model in this paper an analytical method was proposed to estimate the rill detachment rate the method is based on the exact analytical solution of rill erosion to the differential equation of rill detachment the rill sediment concentration distribution as a function of rill length was identified through laboratory experiments under different slope gradients and flow rates the sediment concentration processes from experiments on loess and purple rills were considered to estimate the rill detachment rates of both soils analytically they were respectively used as a function of rill length and sediment concentration the analytical detachment rates were compared with the numerically determined values to verify the analytical methods the rill detachment rates of the two soils under different flow rates and slope gradients estimated by the analytical method were further compared on the basis of detachment sediment function and detachment rill length function results indicated that the analytically estimated values were very close to the numerically estimated values numerical and analytical methods were equally useful for rill detachment rate estimation therefore the analytical method was verified to be rational and applicable for the rapid determination of the rill detachment rates based on either sediment concentration or rill length the analytical detachment values of purple and loess soils suggested that the detachment rates of loess soil were significantly and considerably higher than those of purple soil the erosion potentials of loess soil were also significant higher than those of purple soil the differences in the erosion of the two soils decreased as the slope gradient and flow rate increased these observations implied that the degree of loess soil erosion was greater than that of purple soil erosion at low slope gradients and flow rates the factors causing these differences may be determined in terms of the properties of the two soils therefore the proposed analytical method in addition to the concepts and direct relationship to erosion process could be applied to obtain the rill detachment rate for the determination of rill erosion model parameters

hydraulic conductivity of homogenized tailings from hard rock mines tailings produced by milling for one extraction from hard rock mines which range in size from clay to fine sand have relatively low hydraulic conductivity k the value of k must be known with a certain degree of certainty to analyze consolidation and seepage conditions in and around tailings ponds in this paper the authors present the results of a laboratory investigation on hydraulic conductivity of homogenized tailings from hard rock mines after describing some of the basic properties of four different materials including mineralogy grain size atterberg limits compaction characteristics and consolidation curves permeability test results are given the hydraulic conductivity value usually varies between 10 4 and 10 5 cm s the effect of various factors on this value including void ratio and grain size is then discussed in relation to predictive models it is shown that a modified version of the kozeny carman equation in which a tortuosity factor and a grain size distribution function are i

the concept of transport capacity in geomorphology the notion of sediment transport capacity has been engrained in geomorphological and related literature for over 50 years although its earliest roots date back explicitly to gilbert in fluvial geomorphology in the 1870s and implicitly to eighteenth to nineteenth century developments in engineering despite cross fertilization between different process domains there seem to have been independent inventions of the idea in aeolian geomorphology by bagnold in the 1930s and in hillslope studies by ellison in the 1940s here we review the invention and development of the idea of transport capacity in the fluvial aeolian coastal hillslope debris flow and glacial process domains as these various developments have occurred different definitions have been used which makes it both a difficult concept to test and one that may lead to poor communications between those working in different domains of geomorphology we argue that the original relation between the power of a flow and its ability to transport sediment can be challenged for three reasons first as sediment becomes entrained in a flow the nature of the flow changes and so it is unreasonable to link the capacity of the water or wind only to the ability of the fluid to move sediment secondly environmental sediment transport is complicated and the range of processes involved in most movements means that simple relationships are unlikely to hold not least because the movement of sediment often changes the substrate which in turn affects the flow conditions thirdly the inherently stochastic nature of sediment transport means that any capacity relationships do not scale either in time or in space consequently new theories of sediment transport are needed to improve understanding and prediction and to guide measurement and management of all geomorphic systems

precise relative locations for earthquakes in the northeast pacific region we report that double difference methods applied to cross correlation measured rayleigh wave time shifts are an effective tool to improve epicentroid locations and relative origin time shifts in remote regions we apply these methods to seismicity offshore of southwestern canada and the u s pacific northwest occurring along the boundaries of the pacific and juan de fuca including the explorer plate and gorda block plates the blanco mendocino revere dellwood nootka and sovanco fracture zones host the majority of this seismicity largely consisting of strike slip earthquakes the explorer juan de fuca and gorda spreading ridges join these fracture zones and host normal faulting earthquakes our results show that at least the moderate magnitude activity clusters along fault strike supporting suggestions of large variations in seismic coupling along oceanic transform faults our improved relative locations corroborate earlier interpretations of the internal deformation in the explorer and gorda plates north of the explorer plate improved locations support models that propose northern extension of the revere dellwood fault relocations also support interpretations that favor multiple parallel active faults along the blanco transform fault zone seismicity of the western half of the blanco appears more scattered and less collinear than the eastern half possibly related to fault maturity wemore use azimuthal variations in the rayleigh wave cross correlation amplitude to detect and model rupture directivity for a moderate size earthquake along the eastern blanco fault lastly the observations constrain the seismogenic zone geometry and suggest a relatively narrow seismogenic zone width of 2 to 4 km less

sediment transport capacity of sheet and rill flow application of unit stream power theory theoretical equations for calculating the unit stream power of both sheet and rill flow were developed and used to predict the sediment transport capacity of such flows independent data sets from three sources representing both finely aggregated clay soils and coarse textured nonaggregated soils sheet rill and composite sheet rill flow systems and a range of slopes were used to test the utility of the method the results were very good and demonstrated the simplicity and robustness of the method for shallow overland flow the best results were obtained when the critical unit stream power at incipient sediment motion was treated as a constant value that was independent of slope the results also suggest that a unique value of critical unit stream power for rill initiation exists that is independent of soil type for noncohesive loams or fine sands and finely aggregated clay soils the sediment transport capacity can be accurately predicted from a knowledge of the physical characteristics of the soil or bed material alone for aggregated clay soils this requires information on the aggregate size distribution and the effects of soil particle size differentiation as flow rates and unit stream powers increase with the transition from sheet to rill flow

soil degradation caused by a high intensity rainfall event implications for medium term soil sustainability in burgundian vineyards the purpose of this paper is to provide a sediment flux quantification in a vineyard context vosne romanee burgundy france where medium term soil budget and sustainability are controlled by complex interactions between natural processes rill erosion and anthropogenic processes earth supply transferred back into the rills by the winegrowers concentrated overland flows during the rainfall event resulted in the incision of 13 major rills in the inter rows carrying a sediment volume of about 4 77 m3 most of the rills were rectilinear and displayed a u shape with strong vertical walls rill incision began about 30 m from the upper plot boundary in the buffer zone located at the lower border of the plot seven fan systems developed from the material originating in one or two contributory rows accumulated volume is estimated at 1 6 m3 data from grain size distribution and rill and fan volumes show that erosion is dominated by rilling 70 of the sediment yield over sheet process 30 of the sediment yield the net exported soil loss corresponding to the balance between natural soil loss and anthropogenic supply ranges between 24 3 t ha 1 and 48 t ha 1 over the plot during one hydrologic event analyses of the grain size distribution in the reference soil sample and in the fans reveal that size selectivity has occurred with preferential export of the fine material 2 mm in the fans to evaluate the relative importance in grain size distribution of natural processes material loss over anthropogenic processes rill filling by winegrowers we simulated the temporal evolution of grain size distribution in surface soil during five successive rainfall events our results clearly show that more than 30 of fine material in surface soil was lost in these few events despite anthropogenic rill filling this fine fraction removal may have considerable impact on vineyard sustainability

comparing characteristics of rainfall and earthquake triggered landslides in the upper minjiang catchment china abstract the upper minjiang catchment is located at the eastern margin of the tibetan plateau and is frequently affected by landslides the two main triggering factors in the region are rainfall and high magnitude seismic shocks such as the 2008 wenchuan earthquake in this paper we present a comparison study of pre conditioning factors that drive the spatial occurrence of landslides in this high elevation region we used a multi temporal landslide inventory that differentiates between rainfall and earthquake triggers based on the analyses of satellite imagery aerial photos and field investigations our investigation revealed that the strongest influences on landslides are lithology and topographic factors the difference between these two triggering factors can also be observed with respect to the relative slope positions rainfall triggered landslides are more frequently found at lower slopes while seismic induced landslides are more evenly distributed on very steep slope sections in particular the steep and deeply incised river terraces in this region are prone to landslides due to their rapid formation this study presents the first analysis that differentiates two main triggering factors in order to understand the influence of rainfall and earthquakes on landslide occurrences in this region our results can also aid in the sustainable management of performance based slope engineering and landslide risk reduction by reporting the differences regarding the spatial distribution of rainfall and seismic triggered slope failures consequently these results can be used by local and regional decision makers for risk management and spatial planning

on finding and using repeating seismic events in and near china 1 a comprehensive search for repeating seismic events was performed using cross correlation on waveforms for 17 898 seismic events in and near china reported in the annual bulletin of chinese earthquakes from 1985 to 2005 we define a repeat as an event pair having a high cross correlation 0 8 for a particular bandwidth 0 5 to 5 hz and time window 5 s before p arrival to 40 s after lg arrival such events typically have hypocenters separated by no more than about 1 km this result enables a determination of median relative location error of around 15 km for global and regional catalogs that locate events in this study one at a time using phase picks the maximum location error is on the order of hundreds of kilometers we use nonnormalized cross correlation values to measure relative amplitudes of event pairs the standard deviation is about 0 06 magnitude units much better than the precision of relative magnitudes for doublet events which we estimate for the chinese catalog to have a standard deviation of 0 36 magnitude units two thousand three hundred and seventy nine events out of the 17 898 or 13 of the events in this catalog are classified as repeats with later years showing an increase in the percentage about half the repeats occur as isolated doublets the rest as multiplets of three or larger up to a 92 event multiplet most of the events appear to be triggered or are due to some earthquake interaction since their recurrence intervals are significantly shorter than would be estimated from tectonic loading

goodbye hazen hello kozeny carman the century old hazen formula for predicting the permeability of sand is based only on the d10 particle size whereas the half century old kozeny carman formula is based on the entire particle size distribution the particle shape and the void ratio as a consequence the hazen formula is less accurate than the kozeny carman formula it is recommended that the former be retired and the latter be adopted

discussion of network model for hydraulic conductivity of sand bentonite mixtures chapuis et al 114 the authors have presented a very interesting research paper in which a network model is used to predict the hydraulic conductivity of sand bentonite mixtures sbms several points of the paper are examined and discussed here in the light of previously published concepts laboratory test results and field data on the same topic past experience is also used to further investigate through questions posed to the authors the capability of their model

forecasting sediment distribution in reservoirs during unstable conditions abstract a method for rapid estimation of slopes of deposited sediment in reservoirs during unstable conditions is presented as the limiting factor determining sediment load in a reservoir is the sediment carrying capacity of a current flowing through a reservoir it is arqued that the slope of deposited sediment must be a function of the latter after deriving an equation relating sediment slope to stream power the latter being regarded as representative of sediment carrying capacity a comparison between calculated and observed sediment slopes for average annual conditions in two south african reservoirs are presented using this equation as basic guideline a semi empirical graph is then presented which relates sediment slope to a factor representing average stream power in reservoirs

physical and mechanical properties of a compacted silty sand with low bentonite fraction compacted granular soils with small additions of bentonite have been used to build geotechnical structures such as impervious liners and cores of zoned earth dams this paper presents a laboratory

empirical measurements of tectonic moment release in nuclear explosions from teleseismic surface waves and body waves summary a method of source parameter estimation based principally on observations of teleseismic long period surface waves is developed and applied to 71 underground nuclear explosions at the balapan shagan river test site in kazakhstan first we quantify the observed radiation patterns of love and rayleigh waves noting that such data place only three linear constraints on the five parameters of the standard point source model for each explosion the three constraints are the strengths of the isotropic sin2 and cos2q components of the observed pattern where is azimuth the five source parameters are the isotropic moment m the doublecouple moment adt and the strike dip and rake angles qs 6 a these last four parameters characterize the inferred faulting tectonic release surface waves which propagate from different seismic events in a geographically tight cluster to a distant station are similar in shape and for very shallow sources the propagation operator can be described by a single wave shape a differential propagation delay and a single amplitude factor containing the effects of attenuation scattering focusing and geometrical spreading the inverse problem is formulated which iteratively solves simultaneously for the path amplitude factors and the three radiation pattern parameters for all events using observed seismograms as the empirical wave shapes we fit 1110 relative measurements of rayleigh and love wave amplitudes to determine path amplitude factors to 29 globally distributed stations and radiationpattern parameters for the 71 explosions second we present a new method for interpreting such radiation patterns in previous studies two of the five source parameters have typically been fixed by making the very restricted assumption of pure dip slip faulting at 45 dip the assumption leads to estimates of strike that are mostly in the north west south east direction at balapan and to estimates of m that correlate very poorly with estimates based upon short period signals p lg however now that excellent yield estimates have become available we can avoid the assumption of pure dip slip faulting instead we can estimate mi from p and lg wave data thus adding a fourth constraint to help in interpreting the teleseismic surface wave amplitudes the outcome is a method for estimating the strike as of faulting associated with tectonic release for each explosion and for estimating the two combinations m sin 6 cos a and mo sin 26 sin a which respectively are the strike slip and dip slip components of the tectonic release the strike directions of inferred faulting at balapan are found to lie in the range 90 120 which conforms better with limited geological information on faulting in the region than does the trend that has long been inferred from assuming pure dip slip faulting we find that without additional information about individual explosions we are not able to provide a high precision isotropic moment or yield estimate from teleseismic surface waves

a description of water and sediment flow in the presence of obstacles with a two dimensional lattice bgk cellular automata model 1 the spatial distribution of water and sediment flow in the presence of obstacles on the soil surface is described with a coupled two dimensional lattice bgk the bhatnagar groos and krook version of the lattice boltzmann equation cellular automata model the model reproduces the main water flow characteristics of the bunte and poesen 1993 experiment well as well as the mean runoff velocity the model also approximates the main features of local scouring and sediment yield of the experiment although the results obtained in two dimensions are encouraging the consideration of the erosive action of the vortexes on a plane perpendicular to the bed would improve the characterization of the scouring patterns in the stagnation points developed upstream from the obstacles index terms 1815 hydrology erosion and sedimentation 1860 hydrology runoff and streamflow 1869 hydrology stochastic processes keywords flow erosion obstacles lattice bgk model cellular automata model

an experimental study on dynamic processes of ephemeral gully erosion in loess landscapes abstract ephemeral gully erosion is widespread on the loess plateau of china to provide theoretical support for constructing numerical models and soil water conservation planning the hydrodynamic characteristics of ephemeral gully flows were studied by laboratory experiments with a physical model we firstly concluded that with the influence of step slope pool or step pool terrain on the bottom of gully channels no obvious or consistent pattern changes were evident in the hydrodynamic parameters along the flow direction secondly the change of hydrodynamic parameters during erosion could be classified into an initially fast changing interval followed by a stable period and the initial adjustment period would become shorter with increasing slope and rainfall intensity thirdly ephemeral gully erosion flows were turbulent and changed frequently in space and time between supercritical and subcritical flows throughout the experiment the reynolds number fluctuated and increased with time with increasing rainfall intensity and gully slope the frequency of larger reynolds numbers increased in addition the froude number also fluctuated but decreased with time and the mean froude number eventually stabilized at 0 5 at different slope angles and rainfall intensities fourthly the distribution of erosional energy was influenced mainly by topography in loess slopes in the case of 20 slopes the inverse ratios of dissipation as soil erosion sediment transport and flow kinetic energy were relatively stable in time and space during ephemeral gully erosion moreover flow velocity shear stress the darcy weisbach friction factor and the manning coefficient were influenced by rainfall intensity to a lesser degree during erosion in the stable interval for 15 and 25 slopes shear stress the darcy weisbach friction factor and manning coefficient of ephemeral gully flow both increased with increasing rainfall intensity flow velocity on the 15 slope decreased initially then increased with increasing rainfall intensity but flow velocity on the 25 slope decreased with increasing rainfall intensity finally the regularity seen in hydrodynamic parameters of ephemeral gully flows occurred despite disturbance from lateral confluences gravity erosion of the channel bank and changes in terrain the sediment transport capacity of ephemeral gully flows increased with usp by a linear function r 0 64 n 99 p

on the use of the kozeny carman equation to predict the hydraulic conductivity of soils the saturated hydraulic conductivity of a soil can be predicted using empirical relationships capillary models statistical models and hydraulic radius theories a well known relationship between permeability and the properties of pores was proposed by kozeny and later modified by carman the resulting equation is largely known as the kozeny carman kc equation although the two authors never published together in the geotechnical literature there is a large consensus that the kc equation applies to sands but not to clays this view however is supported only by partial demonstration this paper evaluates the background and the validity of the kc equation using laboratory permeability tests test results were taken from publications that provided all of the information needed to make a prediction void ratio and either the measured specific surface for cohesive soils or the gradation curve for noncohesive soils the paper shows how to estimate the specific surface of a noncohesive soil from its g