modeling of water rock interaction in the mackenzie basin competition between sulfuric and carbonic acids the chemical weathering of continental surfaces depends on many factors including lithology climate tectonics erosion soil or vegetation and also on the availability of acidity in the weathering zone in addition to atmospheric soil co2 sulfide oxidation may represent a significant source of protons for weathering reactions as shown previously for the rivers draining the mackenzie basin canada here a numerical model describing continental weathering reactions based on laboratory kinetic laws is coupled to a dynamic global vegetation model the b witch model in order to estimate the impact of sulfide oxidation on chemical weathering and associated atmospheric co2 consumption fluxes throughout the mackenzie river basin the model is first calibrated with available field data for the various sub basin of the mackenzie watershed and then a simulation is performed removing the contribution of sulfuric acid to the weathering system the main outcomes of the present study are that 1 the dissolved silica export is controlled by secondary minerals reactivity in soils and the calcium and magnesium fluxes are driven by the dissolution of calcite and dolomite 2 the atmospheric co2 consumption by weathering processes in the mackenzie river is limited accounting for only 24 of the total bicarbonate flux to the ocean confirming a previous study and suggesting that weathering processes in the mackenzie watershed acts as a source of carbon to the atmosphere at the geological timescale and 3 the presence of sulfide minerals within a river basin decreases the apparent net consumption of atmospheric co2 through chemical weathering we show that the actual production of sulfuric acid in the weathering zone of the mackenzie basin reduces the net atmospheric co2 consumption by about two compared to what the atmospheric co2 consumption should be in the absence of sulfide minerals sulfuric acid driven chemical weathering has thus to be considered at both short and long timescales when looking at the link between chemical weathering and the global carbon cycle

quick clay a case study of chemical perspective in southwest sweden quick clay a soil that changes from normal firm ground to a liquid mass when it is disturbed has been involved in most of the large and serious clay slides in sweden norway and canada the location time of occurrence and size of quick clay slides are difficult to predict and large slides may cause great devastation some geochemical studies of swedish quick clay were done in the 1960s and early 1970s but no systematic studies of the interrelationships of pore water chemistry mineralogy geotechnical properties and other parameters on quick clays in sweden have been published such studies are of national and general interest because of the many combinations of rock flour source areas and sedimentation conditions that occurred across central sweden and into the baltic sea area during deglaciation in this study geotechnical properties related to the in situ chemistry at one quick clay site were extensively studied and spot sampling was conducted at two other locations in southwest sweden in this area the clay minerals mainly are non expanding phyllosilicate minerals illite and primary minerals quartz feldspar which is consistent with previous studies of quick clay mineralogy extensive leaching has occurred at all three locations at the extensively studied site surte the lowest salinity was found at the greatest depth inferring that the leaching by fresh water was accomplished by water movement upward and laterally through the sediment from the underlying bedrock this is consistent with the local setting where bedrock hills rise sharply to over 100 m above the marine sediment surface an artesian pressure would also be anticipated at this location there is a correlation negative between sensitivity and salinity but there is an indication that the maximum salinity or electrical conductivity consistent with the quick clay behaviour is higher than reported elsewhere however for high sensitivities the salinity is about the same as reported elsewhere in the deepest part of the borehole there is a higher content of fe and al in the pore water indicating reduced state further work is needed to confirm the difference in salinity and to investigate the possible interplay of salinity and potential dispersing agents such as the role of anoxic conditions in this region further work is especially needed in the locations where the sediment accumulation occurred under lower salinity conditions at all three locations high remoulded shear strength and low sensitivity have been seen near the surface together with a decrease in pore water cation concentrations

groundwater surface waters interactions at slope and catchment scales implications for landsliding in clay rich slopes understanding water infiltration and transfer in soft clay shales slopes is an important scientific issue especially for landsliding geochemical investigations are carried out at the super sauze and draix laval landslides both developed in the callovo oxfordian black marls with the objective to define the origin of the groundwater in situ investigations soil leaching experiments and geochemical modeling are combined to identify the boundaries of the hydrological systems at super sauze the observations indicate that an external water flow occurs in the upper part of the landslide at the contact between the weathered black marls and the overlying formations or at the landslide basement through a fault network such external origin of water is not observed at the local scale of the draix laval landslide but is detected at the catchment scale with the influence of deep waters in the streamwater quality of low river flows hydrogeological conceptual models are proposed emphasizing the role of the interactions between local slope and regional catchment flow systems the observations suggest that this situation is a common case in the alpine area expected consequences of the regional flows on slope stability are discussed in term of rise of pore water pressures and physicochemical weathering of the clay shales

soil hydraulic properties in a marly gully catchment draix france abstract runoff is one of the main factors controlling gully development concentrated flow erosion occurs where flow discharge and velocity exceed critical values in southern french alps in black marl gully catchments runoff from hillslopes occurs in the form of hortonian overland flow because rainfall intensities exceed the infiltration capacity of the soil in such a situation spatial variability of infiltration capacities is critical for describing the runoff production this study reports detailed field measurements of near saturation and saturated infiltration properties capillary sorptivity s and hydraulic conductivity k a total of 140 infiltration tests were conducted using tension disc and ponded ring infiltrometers on 6 different regoliths weathering profile encountered in a marly gully catchment the main objectives were to improve our knowledge of the spatial variability of infiltration in black marl areas and to compare different field and data analysis methods hydraulic conductivity values k h at supply pressure heads h ranging from h 100 up to h 0 mm were calculated using steady state flow and wooding s equation wooding r a 1968 steady infiltration from shallow circular pond water resour res 4 6 1259 1273 k h 0 mm was also estimated from the ponded ring infiltrometer data set the estimation of sorptivity was based on transient flow and the solution of haverkamp et al haverkamp r roos p j smettem k r j parlange j y 1994 three dimensional analysis of infiltration from the disc infiltrometer 2 physical based infiltration equation water resour res 30 11 2931 2935 three methods were used to analyse tension disc infiltrometer data multiple radii multiple potential and single test only the multiple radii method was found not suitable in our context due to a large spatial variability in the infiltration properties over small distances the other methods gave similar estimates of the hydraulic conductivity the hydraulic conductivity k h ranged up to two orders of magnitude this result confirms the role played by structural voids when the regolith is at near saturation the dispersion of the estimates of field saturated hydraulic conductivity is larger than unsaturated values the spatial differences found are explained by the topographical position and by the regolith structure observed for the 6 sites an analysis based on the ponding time show that the regolith type plays an important role in the dynamic of the runoff production

urban effects on flood plain natural hazards wolf river tennessee usa abstract the wolf river and its flood plain in the city of memphis and shelby county tn have been extensively altered since the flood plain underwent liquefaction during the earthquakes of 1811 1812 flood plain denudation and aggradation primarily cut and fill are documented by subtracting flood plain surface elevations obtained in the 1940s 1965 1988 and 2001 the resultant maps cross sections and histograms illustrate the complex history and extreme changes that the flood plain has undergone as a consequence of these post 1940s changes liquefaction potential of the flood plain is now very complex the flood plain s area has locally been diminished by approximately 50 thereby requiring remapping of the areas that will be inundated by 100 and 500 year floods and entrenchment of the wolf river and its flood plain may have increased connectivity between wolf river water and shelby county s aquifer

image based mapping of surface fissures for the investigation of landslide dynamics abstract the development of surface fissures is an important indicator for understanding and forecasting slope movements landslide investigations therefore frequently include the elaboration and interpretation of maps representing their spatial distribution typically comprising intensive field work and instrumentation it is only recently that aerial photography with sub decimetre spatial resolution is becoming more commonly available and opens a window to analyse such features from a remote sensing perspective while these data are in principle helpful to elaborate maps from image interpretation techniques there is still no image processing technique available to extract efficiently these geomorphological features this work proposes a largely automated technique for the mapping of landslide surface fissures from very high resolution aerial images the processing chain includes the use of filtering algorithms and post processing of the filtered images using object oriented analysis the accuracy of the resulting maps is assessed by comparisons with several expert maps in terms of affected area fissure density and fissure orientation under homogenous illumination conditions true positive rates up to 65 and false positive rates generally below 10 are achieved the resulting fissure maps provide sufficient detail to infer mechanical processes at the slope scale and to prioritize areas for more detailed ground investigations or monitoring

infrasound radiated by the gerdec and chelopechene explosions propagation along unexpected paths summary infrasound propagation paths through the atmosphere are controlled by the temporally and spatially varying sound speed and wind speed amplitudes because of the complexity of atmospheric acoustic propagation it is often difficult to reconcile observed infrasonic arrivals with the sound speed profiles predicted by meteorological specifications this paper provides analyses of unexpected arrivals recorded in europe and north africa from two series of accidental munitions dump explosions recorded at ranges greater than 1000 km two explosions at gerdec albania on 2008 march 15 and four explosions at chelopechene bulgaria on 2008 july 3 the recorded signal characteristics include multiple pulsed arrivals celerities between 0 24 and 0 34 km s 1 and some signal frequency content above 1 hz often such characteristics are associated with waves that have propagated within a ground to stratosphere waveguide although the observed celerities extend both above and below the conventional range for stratospheric arrivals however state of the art meteorological specifications indicate that either weak or no ground to stratosphere waveguides are present along the source to receiver paths by incorporating realistic gravity wave induced horizontal velocity fluctuations into time domain parabolic equation models the pulsed nature of the signals is simulated and arrival times are predicted to within 30 s of the observed values 1 per cent of the source to receiver transit time modelling amplitudes is highly dependent upon estimates of the unknown acoustic source strength or equivalent chemical explosive yield current empirical explosive yield relationships derived from infrasonic amplitude measurements from point source chemical explosions suggest that the equivalent chemical yield of the largest gerdec explosion was of the order of 1 kt and the largest chelopechene explosion was of the order of 100 t when incorporating these assumed yields the parabolic equation simulations predict peak signal amplitudes to within an order of magnitude of the observed values as gravity wave velocity perturbations can significantly influence both infrasonic arrival times and signal amplitudes they need to be accounted for in source location and yield estimation routines both of which are important for explosion monitoring especially in the context of the comprehensive nuclear test ban treaty

a physically based model for the topographic control on shallow landsliding a model for the topographic influence on shallow landslide initiation is developed by coupling digital terrain data with near surface through flow and slope stability models the hydrologic model topog o loughlin 1986 predicts the degree of soil saturation in response to a steady state rainfall for topographic elements defined by the intersection of contours and flow tube boundaries the slope stability component uses this relative soil saturation to analyze the stability of each topographic element for the case of cohesionless soils of spatially constant thickness and saturated conductivity the steady state rainfall predicted to cause instability in each topographic element provides a measure of the relative potential for shallow landsliding the spatial distribution of critical rainfall values is compared with landslide locations mapped from aerial photographs and in the field for three study basins where high resolution digital elevation data are available tennessee valley in marin county california mettman ridge in the oregon coast range and split creek on the olympic peninsula washington model predictions in each of these areas are consistent with spatial patterns of observed landslide scars although hydrologic complexities not accounted for in the model e g spatial variability of soil properties and bedrock flow control specific sites and timing of debris flow initiation within areas of similar topographic control

an empirical model of the earth s horizontal wind fields hwm07 1 the new horizontal wind model hwm07 provides a statistical representation of the horizontal wind fields of the earth s atmosphere from the ground to the exosphere 0 500 km it represents over 50 years of satellite rocket and ground based wind measurements via a compact fortran 90 subroutine the computer model is a function of geographic location altitude day of the year solar local time and geomagnetic activity it includes representations of the zonal mean circulation stationary planetary waves migrating tides and the seasonal modulation thereof hwm07 is composed of two components a quiet time component for the background state described in this paper and a geomagnetic storm time component dwm07 described in a companion paper

estimation of the water balance of alluvial aquifers in region of high isotopic contrast an example from southeastern france the much contrasted orographic and climatic characters of southeastern france serve to establish a hydrological balance of the porous aquifers in the region comparing a regional average gradient of 18o content versus elevation which was calculated on low water period karst waters content with a 10 5 average d of alpine rivers an estimate of the percentages brought to these aquifers is proposed under the form of an abacus it appears that the main groundwaters of the var the durance and the rhone are fed by an average of 20 30 of provencal underground contribution and 70 80 shallow contribution from the alpine rivers these figures reveal that local supplies range between 25 and 10 of the average yearly discharge flowing in the porous and shallow aquifers

seismo acoustic signals of the baumgarten austria gas explosion detected by the alparray seismic network abstract on december 12 2017 a devastating release and combustion of gas occurred at the baumgarten gas hub in eastern austria which is a major european distribution node for natural gas we have detected the resulting seismo acoustic signal on permanent and temporary broadband seismic stations at distances between 30 and 175 km from the gas hub most prominently in the 2 4 hz range two distinct phase arrivals correspond to acoustic waves traveling through the troposphere and stratosphere the passing of a cold front shortly before the explosion led to several temperature inversions at low altitude and acoustic waveguides within the troposphere that facilitated our infrasound detections at distances as close as 50 km from the source in addition to the commonly observed stratospheric reflections 3d acoustic raytracing using temperature and wind velocities from the hres high resolution forecast model of the european center for medium range weather forecast ecmwf has allowed to precisely relate the spatial distribution of our detections with calculated surface bounce points of infrasound rays this has provided a precise and independent estimate of the time of the accident to be used in forensic investigations in addition to the acoustic signal we find evidence for weak seismic phases on the stations closest to the gas hub yet the sudden release of gas above the surface generated acoustic waves more effectively than seismic waves after the first explosion signal we also detect a prolonged coda of elevated noise which is probably due to ongoing gas release and or the fire from the escaping gas systematic analyses like the one conducted here are of great value to detect locate and characterize anthropogenic sources at a regional scale

a seismoacoustic analysis of the gas pipeline explosion near ghislenghien in belgium a high pressure gas pipeline exploded near ghislenghien in belgium on 30 july 2004 seismic energy of this event was recorded at three nearby seismometers the origin time of the explosion was determined by analyzing the rayleigh waves and found to be 06h55m27 2sec coordinated universal time utc ground truth of the explosion was invoked to assess the accuracy of the location derived from infrasound data recorded over western europe different infrasonic phases were identified by using array processing techniques and raytracing through atmospheric models the analysis showed that the derived location was situated 13 km from the true location the total area of the uncertainty ellipse or area to be searched if the source was of unknown origin was 690 km 2 after the origin time and location the yield was calculated by comparing infrasonic stratospheric amplitudes with those from a high explosives dataset and was estimated at 40 9 tons high explosives equivalent in summary this study illustrates the capability of seismic and infrasound data in forensic investigations furthermore the potential of infrasound as a monitoring or verification technique is addressed

hydrological response of weathered clay shale slopes water infiltration monitoring with time lapse electrical resistivity tomography this work presents an attempt to monitor water infiltration and subsurface flow within a clay shale landslide using time lapse electrical resistivity tomography ert a rainfall experiment was carried out on a plot of 100 m2 at the laval landslide in the draix experimental catchments ore draix south french alps in order to characterize the spatial and temporal development of water circulation in the soil and to identify when steady state flow conditions are reached the experiment was conducted during 67 h with initial unsaturated conditions in the slope the apparent electrical resistivity values were inverted with a time lapse approach using several cross models the results indicate a significant decrease in resistivity 18 compared to the initial state in the rain plot downslope progression of negative resistivity anomalies is imaged suggesting that vertical and subsurface lateral flows have developed about 21 h after the start of the rain experiment a constant level of resistivity values is observed indicating that the hydrological system reached steady state flow conditions this observation is consistent with ground water level observations and chemical tracer analysis computed differences in time of steady state conditions highlight possible preferential flows near the landslide toe a hydrological concept of functioning of the slope is proposed and apparent saturated hydraulic conductivity ks of 1 7 10 4 m s 1 is computed from the steady state times this study demonstrates the potentiality of ert monitoring to monitor water infiltration in clay shale slopes and the high water transfer capacity of reworked clay shale material

teleseismic slowness azimuth station corrections for the international monitoring system seismic network abstract the prototype international data center pidc in arlington virginia has been developing and testing software and procedures for use in the verification of the comprehensive test ban treaty after three years of operation with a global network of array and three component stations it has been possible to characterize various systematic biases of those stations that are designated in the treaty as part of the international monitoring system ims these biases include deviations of azimuth and slowness measurements from predicted values caused largely by lateral heterogeneity for events recorded by few stations azimuth and slowness are used in addition to arrival time data for location by the pidc corrections to teleseismic azimuth and slowness observations have been empirically determined for most ims stations providing data to the pidc application of these corrections is shown to improve signal association and event location at some stations an overall systematic bias can be ascribed to local crustal structure or to unreported instrumental problems the corrections have been applied in routine operation of the pidc since february 1998

geological discontinuities main flow path and chemical alteration in a marly hill prone to slope instability assessment from petrophysical measurements and borehole image analysis clay shale landscapes are sensitive to landslide erosion and re sedimentation processes in this context tectonized clay shales have peculiar hydrological and mechanical behaviours in order to improve our understanding of the processes involved in such systems an experimental site has been settled in the draix observatory ore draix on a black marl hill slope of the southern alps france in the framework of the ecou pref project the site is a natural laboratory to study the evolution of clay shale landscapes at several scales regional to m in this study we aim to characterize the internal structure and fissure patterns of a stable interfluve in order to locate preferential water flows within the system and anticipate its evolution this work is based on a series of mutli disciplinary approaches including petrophysical analyses well pulse injection tests and downhole geophysical measurements borehole geophysical results were combined with laboratory measurements on core plugs permeability density porosity and acoustic velocity optical and acoustical images have been used as an original tool for internal discontinuities characterisation and potential active flow path detection they allowed the identification of three main lithological units interpreted as several stages of shale alteration in addition several main structural plane discontinuities open fractures schistosity planes and fractures infilled with calcite or clays were identified from the images and their potential transmissivity discussed with regard to piezometric and tracer measurements in all the integration of measurements leads to propose a simple scenario of fluid circulation and chemical alteration of the interfluve copyright 2011 john wiley sons ltd

an automatic seismic event processing for detection and location the p m c c method we present a new method for automatic detection and location of seismic events recorded on a network it is based on a progressive study of the interstation correlation functions which leads to a consistent set of time delays when a seismic phase is present three different examples are processed on networks of different sizes

a view on some hydrological triggering systems in landslides abstract in this paper different types of hydrological triggering systems for debris flows shallow and deeper landslides are described the generation of surface run off and high peak discharges in first order alpine catchments is an important triggering mechanism for debris flows failure conditions in shallow landslides can occur when at a critical depth which is determined by the cohesion of the soil and the slope angle the moisture content in the soil becomes close to saturation resulting in a considerable reduction of soil strength deeper landslides 5 20 m depth are in most cases triggered by positive pore pressures on the slip plane induced by a rising ground water level the assessment of meteorological threshold conditions for shallow landslides 1 2 m needs more detailed meteorological information than for deeper landslides in the analyses of the hydrological triggering systems of deeper landslides the presence of a permeable top layer and fissures has to be taken into consideration

global morphology of infrasound propagation i atmospheric sound waves in the 0 02 10 hz region also known as infrasound exhibit long range global propagation characteristics measurable infrasound is produced around the globe on a daily basis by a variety of natural and man made sources as a result of weak classical attenuation 0 01 db km 1 at 0 1 hz these acoustic signals can propagate thousands of kilometers in tropospheric stratospheric and lower thermospheric ducts to model this propagation accurately detailed knowledge of the background atmospheric state variables the global winds and temperature fields from the ground to 170 km is required for infrasound propagation calculations we have developed a unique atmospheric specification system g2s that is capable of providing this information using acoustic ray tracing methods and detailed g2s atmospheric specifications we investigate the major aspects of the spatiotemporal variability of infrasound propagation characteristics

landslides and climatic conditions in the barcelonnette and vars basins southern french alps france research into the climatic causes behind the triggering and reactivation of landslides has been carried out in two basins in the southern french alps where a great many landslides have occurred over more than a century correlations between landslides and climate are sometimes precise and closely related in time at other times imprecise and more distant the better known the type of landslide and the date of its occurrence the greater the correlation may appear be this as it may climate is never the sole cause this paper deals with the limits of the effects of climate

seismo acoustic analysis of the buncefield oil depot explosion in the uk 2005 december 11 summary a massive vapour cloud explosion occurred at the buncefield fuel depot near hemel hempstead uk in the morning of 2005 december 11 the explosion was the result of an overflow from one of the storage tanks with the release of over 300 tons of petrol and generating a vapour cloud that spread over an area of 80 000 m2 before being ignited considerable damage was caused in the vicinity of the explosion and a total of 43 people were injured the explosion was detected by seismograph stations in the uk and the netherlands and by infrasound arrays in the netherlands we analysed the seismic recordings to determine the origin time of 06 01 31 45 0 5 s utc from p wave arrival times uncertainties in determination of origin time from acoustic arrival times alone were less than 10 s amplitudes of p lg and primary acoustic waves were measured to derive decay relationships as function of distance from the seismic amplitudes we estimated a yield of 2 10 tons equivalent to a buried explosion most seismic stations recorded primary and secondary acoustic waves we used atmospheric ray tracing to identify the various travel paths which depend on temperature and wind speed as function of altitude leading to directional variation refracted waves were observed from the troposphere stratosphere and thermosphere with a good match between observed and calculated traveltimes the various wave types were also identified through array processing which provides backazimuth and slowness of recordings from an infrasound array in the netherlands the amplitude of stratospheric refracted acoustic waves recorded by the array microbarometers was used to estimate a yield of 21 6 5 tons tnt equivalent we have demonstrated through joint seismo acoustic analysis of the explosion that both the seismic velocity model and the atmospheric model are sufficient to explain the observed traveltimes

hydrological and hydrochemical processes observed during a large scale infiltration experiment at the super sauze mudslide france rainfall is one of the major triggering factors of landslides and its pattern controls their temporal behaviour characterization of the groundwater processes and possible preferential infiltration of rainfall is necessary challenging and very relevant for landslide hazard analysis the objective of this paper is to identify the groundwater dynamics matrix flow and preferential flow within highly heterogeneous and fissured reworked black marl material using a large scale infiltration test the artificial rainfall experiment over a 100 m2 infiltration plot monitored with several hydrological hydrochemical and geophysical equipments was carried out on the super sauze mudslide south french alps high resolution groundwater and water quality measurements were collected artificial rainfall was applied over a period of 14 days conservative tracers br and cl were used successively during the infiltration period the mean rainfall intensity was 8 5 mm h 1 with a mean tracer concentration of 100 mg l 1 the hydrodynamic and hydrochemical responses of the tracing experiments allowed us to get a new insight into 1 the horizontal and vertical variability of the rain infiltration in unstable black marl hillslopes 2 the effect of shallow fissuration on the groundwater recharge 3 the role of piston flow on the rate of water level changes and the increase of pore water pressures and 4 the effect of material heterogeneity in the development of preferential water flows and local perched water tables copyright 2011 john wiley sons ltd

acquisition of water chemistry in a mobile fissured basement massif its role in the hydrogeological knowledge of the la clapiere landslide mercantour massif southern alps france abstract groundwater flowpaths of the la clapiere landslide are studied by chemical and isotopic water analysis and modeling of the landslide springs in our case it appears that sulfate can be taken as a chemical tracer of the different flowpaths on the gneissic slope of la clapiere geochemical modeling explains sulfate concentrations from 0 to 130 mg l by dissolution of sulfurous minerals present in the gneisses such a variability of the concentrations measured in the springs is due to different infiltration paths direct paths through the basement so 4 2 10 60 mg l or indirect path through superficial deposits like screes or fluvio glacial terrains which cover the basement so 4 2 60 130 mg l the high concentrations 600 800 mg l cannot be explained by thermodynamic geochemical simulations and they reveal triassic gypsum dissolution hidden under the studied slope so two main flowpaths are differentiated in the la clapiere landslide 1 flow through low permeable triassic deposits pinched under the foot of the landslide 2 flow through a more permeable fissured basement with different flow paths and consequently with different transit times due to the anisotropic nature of the top and the central part of the landslide

groundwater characterisation and modelling of water rock interaction in an argillaceous formation tournemire france abstract chemical na k mg ca cl so 4 hco 3 si al fe mn toc and isotopic 18 o h 2 o 2 h h 2 o 3 h h 2 o 14 c dic 13 c dic 34 s so 4 18 o so 4 data were obtained on groundwater collected from fractures inside the consolidated argillaceous formation of tournemire aveyron and from the aquifers surrounding this formation because of the very low transmissivity of such fractures 10 10 m 2 s 1 specific devices were developed for limiting out gassing and air contamination of groundwater during the sampling two modelling approaches are proposed to account for the chemical evolution of fracture groundwater from na cl hco 3 to na so 4 type the first one is based on mineral equilibria only and the second one also takes into account the ion exchange reactions the two modelling approaches are able to reproduce k concentrations and they led to an almost constant p co 2 10 2 6 atm which only depends on equilibrium with the calcite dolomite kaolinite quartz assemblage the modelling of na ca 2 and hco 3 behaviours is improved by taking the ion exchange reactions into account in some boreholes the time evolution of the chemical composition of fluids was greatly influenced by so 4 reduction combined with oxidation of dissolved organic c the isotopic composition of aqueous so 4 in fracture groundwater confirms that so 4 reduction processes have occurred since the drilling of these boreholes but also previously during the natural evolution of groundwater these redox reactions constitute a source of aqueous inorganic c that has to be considered in the computation of groundwater ages with 14 c for the studied fracture groundwaters the maximum age estimates range from 17 to 29 ka this shows that fractures may induce relatively fast groundwater flow compared to the very long migration times that are calculated by only considering diffusive transport in the rock microporosity

cation exchanged fe ii and sr compared to other divalent cations ca mg in the bure callovian oxfordian formation implications for porewater composition modelling abstract iron and sr bearing phases were thoroughly investigated by means of spectrometric and microscopic techniques in callovian oxfordian cox samples originating from the andra underground research laboratory url in bure france strontium was found to be essentially associated with celestite whereas fe was found to be distributed over a wide range of mineral phases iron was mainly present as fe ii in the studied samples 93 from mossbauer results most of the fe ii was found to be in pyrite sideroplesite ankerite and clay minerals iron iii if present was associated with clay minerals probably illite illite smectite mixed layer minerals and chlorite no fe iii oxy hydro xide could be detected in the samples strontianite was not observed either based on these observations it is likely that the cox porewater is in equilibrium with the following carbonate minerals calcite dolomite and ankerite sideroplesite but not with strontianite it is shown that this equilibrium information can be combined with clay cation exchange composition information in order to give direct estimates or constraints on the solubility products of the carbonate minerals dolomite siderite and strontianite as a consequence an experimental method was developed to retrieve the cation exchanged fe ii in very well preserved cox samples the very homogeneous cation exchange composition of the formation is completely in agreement with a homogeneous presence of calcite and dolomite minerals whose equilibrium reactions control part of the porewater composition amongst the broad range of values available for dolomite solubility products in thermodynamic databases the value of log kdolomite 3 57 is the most appropriate for the one present in the cox formation with regard to strontianite it appears that the equilibrium constant tabulated in the llnl database is not valid for natural clay systems the value given by busenberg et al used by most of the other available thermodynamic databases seems to be far more appropriate concerning fe ii and siderite ankerite equilibrium the measured fe ca ratio on the clay exchanger 0 01 could only be considered as a maximum value due to possible experimental bias leading to the following constraint for the solubility of the sideroplesite phase present in the cox fe0 7mg0 2ca0 1co3 h 0 7 fe2 0 2 mg2 0 1 ca2 hco 3 logksid cox this constraint is in agreement with the estimated solubility of this phase based on a solid solution model log ksid cox 0 23

experimental analysis of groundwater flow through a landslide slip surface using natural and artificial water chemical tracers artificial and natural tracer tests combined with high accurate electronic distancemeter measurements are conducted on a small landslide with a well known slip surface geometry outflow yields and chemical contents are monitored for all the experiment duration and they analyzed to estimate the slip surface hydraulic parameters the main result is that the slip surface acts as a drain for groundwater flows that evacuates interstitial pressures in the slope and brings the sliding mass to be more stable one

large scale rainfall simulation to investigate infiltration processes in a small landslide under dry initial conditions the draix hillslope experiment few studies exist on infiltration processes in badlands although infiltration and subsurface lateral flows are known to contribute to soil erosion and to control slope instability our investigation was carried out in a 100 m plot located in a 0 5 ha landslide in black marls south east france an artificial sprinkling was performed with an intensity of 10 mm h 1 during 66 4 h interrupted with 8 4 h breaks kbr and kcl were used as tracers a pseudo steady state was reached after 25 35 h and 250 350 mm of rainfall the runoff coefficient was 40 ratio total runoff volume total sprinkling water amount pre event water pe contributed to the groundwater recharge at the very beginning of the experiment but pe contribution dropped steadily while the soil was saturating after around 200 mm of cumulative rainfall pe contribution started to rise steeply before reaching a nearly constant value this original mechanism implies an efficient transfer process of pe it was assumed from the description of the material structure and from hydrological evidences that pe was mainly drained from a structure porosity made of marl s flaked nature total pe contributions ranged from 25 to 79 pe contribution was over 50 in 2 3 of the observation wells over the recession phase release of pe occurred from the drainage of texture porosity the study showed that at the plot scale infiltration processes proved to be well organized despite the high heterogeneity and anisotropy of the material it was possible to propose a general conceptual model explaining the hydrological processes over time and area the peculiar structure of regolith originating from black marl is preserved over a large part of the weathering time so that the material structure type orientation of grains small large pores remains a first order control of water flow generation in black marl soils copyright 2012 john wiley sons ltd

identifying the origin of groundwater and ﬂow processes in complex landslides affecting black marls insights from a hydrochemical survey the super sauze mudslide is a persistently active slow moving landslide occurring in the black marl outcrops of the french south alps it has been intensively studied since the early 1990s geotechnical geomorphological geophysical and hydrological investigations have led to a better understanding of the processes governing the landslide motion water ows inside the system have been proven to have a major impact to look closer at the processes involved and especially to gain a better idea of the origin and pathways of the waters a hydrochemical study was carried out from may 2003 to may 2004 the groundwater was sampled during ve eld campaigns spread uniformly over the year groundwater from a network of boreholes was collected as well as spring waters from the fractured bedrock in situ black marl and from the moraine aquifer above the landslide results showed that the groundwater chemistry could not be fully explained by rainfall recharge or simple water matrix equilibrium a contribution of saline waters coming from the bottom of a thrust sheet overhanging the landslide was required to get the observed high mineralization on a ow line the hydrochemical evolution was related to both soil matrix equilibrium and deep water sources coming up to the surface by means of major faults the bedding planes and the schistosity hydrochemical anomalies made it possible to point out such contributions locally it was shown that water chemistry and landslide activity were closely related this hydrochemical investigation also enabled us to better de ne the hydrosystem limits copyright 2006 john wiley sons ltd

joint seismic infrasonic processing of recordings from a repeating source of atmospheric explosions a database has been established of seismic and infrasonic recordings from more than 100 well constrained surface explosions conducted by the finnish military to destroy old ammunition the recorded seismic signals are essentially identical and indicate that the variation in source location and magnitude is negligible in contrast the infrasonic arrivals on both seismic and infrasound sensors exhibit significant variation both with regard to the number of detected phases phase travel times and phase amplitudes which would be attributable to atmospheric factors this data set provides an excellent database for studies in sound propagation infrasound array detection and direction estimation

effect of interarray elevation differences on infrasound beamforming summary the international monitoring system infrasound network will upon completion contain 60 microbarometer arrays with apertures of between 1 and 4 km these arrays are located within a variety of terrains leading to large ratios of interelement elevation differences to array aperture for those arrays situated in areas of significant topography systematic errors in beamforming estimates caused by neglecting the vertical extent of the arrays are quantified for both signal backazimuth and apparent velocity of the 43 arrays certified as of 2011 january i14cl on juan fernandez island has the greatest topography across an array with a least squares fitted plane through the array elements having an 8 1 slope from the horizontal compared to a network mean of 1 6 beamforming errors both backazimuth and apparent velocity are a function of the arrival azimuth and become increasingly large for steeply inclined arrivals such that systematic errors will be significantly larger for signals returned from the thermosphere compared to those from the stratosphere at several arrays azimuthal errors due to array topography are comparable in magnitude to deviations often associated with atmospheric propagation these findings are illustrated using signals recorded in greenland at i18dk where differences between results processed using both full 3 d array geometry and the 2 d topography neglected approximation exhibit good correspondence to theoretical predictions

biogeochemical processes in a clay formation in situ experiment part e equilibrium controls on chemistry of pore water from the opalinus clay mont terri underground research laboratory switzerland the chemistry of pore water particularly ph and ionic strength is an important property of clay rocks being considered as host rocks for long term storage of radioactive waste pore waters in clay rich rocks generally cannot be sampled directly instead their chemistry must be found using laboratory measured properties of core samples and geochemical modelling many such measurements have been made on samples from the opalinus clay from the mont terri underground research laboratory url several boreholes in that url yielded water samples against which pore water models have been calibrated following a first synthesis report published in 2003 this paper presents the evolution of the modelling approaches developed within mont terri url scientific programs through the last decade 1997 2009 models are compared to the composition of waters sampled during dedicated borehole experiments reanalysis of the models parameters and database enabled the principal shortcomings of the previous modelling efforts to be overcome the inability to model the k concentrations correctly with the measured cation exchange properties was found to be due to the use of an inappropriate selectivity coefficient for na k exchange the inability to reproduce the measured carbonate chemistry and ph of the pore waters using mineral water reactions alone was corrected by considering clay mineral equilibria re examination of the measured ca mg activity ratios and consideration of the mineralogical composition of the opalinus clay suggested that ca mg cation exchange rather than dolomite saturation may control the ratio of these ions in solution this re examination also suggests that the ca mg ratio decreases with increasing pore water salinity several possible reasons for this are proposed moreover it is demonstrated that feldspar equilibria must not be included in opalinus clay modelling because feldspars are present only in very small quantities in the formation and because na k ratios measured in pore water samples are inconsistent with feldspar saturation the principal need to improve future modelling is additional or better data on rock properties in particular i a more detailed identification of phases in the opalinus clay that include redox sensitive elements together with evaluation of their thermodynamic properties ii an improved understanding of the distribution of celestite throughout the opalinus clay for sr so4 concentrations control iii improvements in analytic and thermodynamic data for ca mg rock cation exchange and mineral chemical properties and iv the measurement of composition and stability constants of clay minerals actually present in the formation

some geomorphological considerations for the future development of landslide models this paper reviews the commonly available models used to model landslides the main purpose is then to examine some of the wider issues associated with the developments that are required if we are to develop 3 d applications and to extrapolate their use to long time scales the paper does not discuss landslide hazard mapping models but concentrates on the 3 d and temporal problems associated with the modelling of single slides

investigation of azimuth residuals observed at stations of the gsett 3 alpha network the gsett 3 experiment was conducted for more than two years and the international data center idc reported more than 20 000 events for 1995 in the reviewed event bulletins reb we have used this data base to investigate the location bias of arrays and selected three component stations in the alpha network for which the recorded data is automatically processed to determine earthquake locations in near real time the alpha network which consists of 14 arrays provides estimates of event azimuths determined by f k processing we selected 19 three component stations that were operated all or most of 1995 and for which event azimuth was estimated by polarization analysis only events with epicentral distances of less than 100 were considered in order to exclude phases with steep incidence angles associated with unreliable azimuth estimates teleseismic p phases and the major regional and local phases were examined only data for which a signal to noise ratio was given were included in this analysis the signal to noise ratios were used as a weighting factor for the statistical parameters and the graphical representation of the azimuth residuals the preliminary analysis of azimuth residuals identified some arrays that give significantly erroneous azimuths in some cases the error is systematic in other cases it is random one array with systematic azimuthal bias is cmar this array shows positive residuals for event paths from the south while phases for events with paths from the north show negative residuals similar patterns which strongly suggest azimuthal bias are observed for pdar txar and spits in the case of mjar the large azimuthal errors observed particularly for regional and local distances are not a function of direction the scatter in the azimuth residuals is much larger for 3 c stations than for the arrays clear systematic errors were identified for schq and cpup which show constant offsets and at vnda which has negative residuals for events to the north and positive residuals for events from the south the most significant azimuth bias was observed for pdy where the azimuth residuals change from about 90 to more than 90 at backazimuths near 120 meaning that all rays appear from the northwest

the 12 december 2017 baumgarten gas hub explosion a case study on understanding the occurrence of a large infrasound azimuth residual and a lack of seismic observations the baumgarten explosion occurred on 12 december 2017 at a gas storage site about 30 km east of vienna austria acoustic arrivals from this accidental surface explosion were detected at dozens of stations of the alparray seismic network to distances up to 150 km mainly in easterly directions thus it was expected that the hungarian infrasound array pszi located about 230 km to the east southeast of baumgarten would detect this acoustic wave as well standard progressive multichannel correlation processing and frequency wavenumber analysis identified a signal emerging at 7 57 55 utc from an azimuth of 296 300 and with trace velocity 400 m s the extraordinarily high trace velocity and excessive backazimuth residual relative to the explosion site direction of 282 however cast strong doubts on the arrival s connection to the baumgarten event accounting for the effect of non planar geometry of the infrasound array results in a reduction of the azimuth residual by half additionally 2d and 3d raytracing methods are used including the european centre for medium range weather forecasts ecmwf atmospheric model to further explain the remaining azimuth residual as well as to elucidate the large trace velocity estimates the prevailing stratospheric winds in excess of 150 m s are identified as the underlying cause including both factors the initial azimuth residual of up to 18 decreases to 4 allowing to associate the infrasound signal at pszi with the baumgarten event finally the data from a seismic station at 30 km range is re investigated for magnitude estimation the local magnitude of ml 1 0 explains well the scarcity of seismic observations within 50 km range where three or four stations show signals mainly consisting of rg type surface waves but no body waves

computer simulation of co2 trapped through mineral precipitation in the rose run sandstone ohio abstract equilibrium path of reaction and kinetic modeling of co2 brine mineral reactions in the rose run sandstone one of ohio s deep saline aquifers was conducted in order to investigate the factors that are likely to influence the capacity of this formation to trap injected co2 as solid carbonate mineral phases equilibrium modeling was applied to investigate the impact of temperature pressure mineralogy brine composition and co2 fugacity on mineral dissolution and precipitation the amount of co2 sequestered and the form of sequestration path of reaction and kinetic modeling were used to evaluate intermediate products and reaction progress as a function of time as well as to investigate the impact of brine to rock ratio the results of equilibrium modeling demonstrate that dissolution of albite k feldspar and glauconite and the precipitation of dawsonite and siderite are potentially very important for mineral trapping of co2 according to the path of reaction and kinetic modelling the stability of carbonate rocks is controlled by the brine to rock ratio the ph of the system the fugacity of co2 and the kinetic rate of dissolution in kinetic modeling with a brine to rock ratio of 1 25 reactive surface area of 10 cm2 g 10 mpa f co 2 and 12 porosity 1 5 2 g of co2 per kg of reacted rock significant quantities 10 40 g of carbonate minerals were precipitated from both the sandstone and mixed rock assemblages the rose run sandstone has the potential to store co2 over millennia as a negatively buoyant aqueous solution and ultimately as immobile carbonate minerals

a process based analysis of ocean heat uptake in an aogcm with an eddy permitting ocean component about 90 of the anthropogenic increase in heat stored in the climate system is found in the oceans therefore it is relevant to understand the details of ocean heat uptake here we present a detailed process based analysis of ocean heat uptake ohu processes in higem1 2 an atmosphere ocean general circulation model with an eddy permitting ocean component of 1 3 resolution similarly to various other models higem1 2 shows that the global heat budget is dominated by a downward advection of heat compensated by upward isopycnal diffusion only in the upper tropical ocean do we find the classical balance between downward diapycnal diffusion and upward advection of heat the upward isopycnal diffusion of heat is located mostly in the southern ocean which thus dominates the global heat budget we compare the responses to a 4xco2 forcing and an enhancement of the windstress forcing in the southern ocean this highlights the importance of regional processes for the global ocean heat uptake these are mainly surface fluxes and convection in the high latitudes and advection in the southern ocean mid latitudes changes in diffusion are less important in line with the cmip5 models higem1 2 shows a band of strong ohu in the mid latitude southern ocean in the 4xco2 run which is mostly advective by contrast in the high latitude southern ocean regions it is the suppression of convection that leads to ohu in the enhanced windstress run convection is strengthened at high southern latitudes leading to heat loss while the magnitude of the ohu in the southern mid latitudes is very similar to the 4xco2 results remarkably there is only very small global ohu in the enhanced windstress run the wind stress forcing just leads to a redistribution of heat we relate the ocean changes at high southern latitudes to the effect of climate change on the antarctic circumpolar current acc it weakens in the 4xco2 run and strengthens in the wind stress run the weakening is due to a narrowing of the acc caused by an expansion of the weddell gyre and a flattening of the isopycnals which are explained by a combination of the wind stress forcing and increased precipitation

instability conditions of marly hillslopes towards landsliding or gullying the case of the barcelonnette basin south east france abstract black marl hillslopes in the french alps are strongly affected either by mass movements or by gully erosion due to their susceptibility to weathering processes this paper presents experimental data geomorphological geotechnical geomechanical and hydrological on the parameters of the material of three well known earthflows and of the two stratigraphic parts of the callovo oxfordian black marl the main objectives are to define the geomechanical behaviour of the various formations using different characterisations grain size distribution mineralogy retention capacity consolidation test direct shear test and triaxial test and to demonstrate how such soils can affect the stability of natural slopes particular care must be taken when interpreting the geomechanical tests on this evolving and very heterogeneous clay rich material there are strong relationships between the parent rock and the landslide materials this paper presents a conceptual model of the development of strength over a period of time and investigates the parameters of the material for use in slope stability analysis and risk assessment

physico chemical effects on the behaviour of a coastal mudslide previous work has shown that the type of clay mineral the valency state of adsorbed cations and the salt concentration of pore water influences the residual strength of clays residual strength can therefore be modified through weathering reactions clay mineral alterations and fluctuations in groundwater chemistry this has implications for studies of the seasonal and long term behaviour of clay slopes the paper presents results from an investigation of a shallow coastal mudslide on the south coast of england which attempts to isolate the influence of physico chemical processes on mudslide behaviour fluctuations in groundwater chemistry coincided with temporal movement patterns low pore water ion concentrations were apparent immediately before seasonal mudslide reactivation or periods of high activity laboratory tests showed that low pore water ion concentrations resulted in low residual shear strength higher concentrations observed after movement events led to increases in residual strength