an integrated geophysical approach for water infiltration detection and characterization at monte cotugno rock fill dam southern italy abstract this study concerns with an integrated geophysical approach for the detection and spatial temporal characterization of the water infiltration into the monte cotugno dam embankment this strategic civil infrastructure is the largest rock fill dam in europe and represents the nodal point of the water system feeding the basilicata puglia and calabria regions southern italy here we propose an approach based on the combination of geophysical techniques as ground penetrating radar gpr and electrical resistivity tomography ert with thermal infrared mapping tir and geotechnical in situ measurements such an approach was applied for the diagnosis of the monte cotugno dam with the aim both to gain information about the geometry of visible micro fractures in the dam coverage and have a rapid mapping of the dam inner areas affected by water infiltration phenomena the sensing methods were deployed in a cascade modality where the thermal infrared tir method was used for surveying the dam along the overall length in order to achieve information about the dam coverage status in particular tir analysis allowed us to identify five areas affected by significant fractures and coating detachment afterwards gpr surveys were performed on the sloping side of the dam by investigating few areas among those identified by tir analysis in this way it was possible to get indications whether the water infiltration affected the deeper parts of the dam lastly electrical resistivity tomography ert method was applied in order to detect deeper inner areas affected by water leakages finally a joint interpretation of the three sensing methods was confirmed by shallow boreholes

geoacoustic inversion with ships as sources estimation of geoacoustic parameters using acoustic data from a surface ship was performed for a shallow water region in the gulf of mexico the data were recorded from hydrophones in a bottom mounted horizontal line array hla the techniques developed to produce the geoacoustic inversion are described and an efficient method for geoacoustic inversion with broadband beam cross spectral data is demonstrated the performance of cost functions that involve coherent or incoherent sums over frequency and one or multiple time segments is discussed successful inversions for the first sediment layer sound speed and thickness and some of the parameters for the deeper layers were obtained with the surface ship at nominal ranges of 20 30 or 50 water depths the data for these inversions were beam cross spectra from four subapertures of the hla spanning a little more than two water depths the subaperture beams included ten frequencies equally spaced in the 120 200 hz band the values of the geoacoustic parameters from the inversions are validated by comparisons with geophysical observations and with the parameter values from previous inversions by other invesigators and by comparing transmission loss tl measured in the experiment with modeled tl based on the inverted geoacoustic parameters

reappraisal of the beekmantown group sedimentology and stratigraphy montreal area southwestern quebec implications for understanding the depositional evolution of the lower middle ordovician laurentian passive margin of eastern canada detailed lithostratigraphic mapping of the beekmantown group of southwestern quebec has refined the field application of the previously proposed tripartite division of the group i e theresa beauharnois and carillon formations the group is a peritidal dominated succession that accumulated on the epicontinental laurentian passive margin biostratigraphic data based on conodonts from this group indicate an early to early middle ordovician age and are partially time correlative with the wallace creek to naylor ledge strata of the philipsburg group southern quebec this conodont biostratigraphy sheds new light on the temporal evolution and depositional framework of the beekmantown platform the platform evolved as a distally steepened ramp during deposition of the theresa formation and the ogdensburg member of the beauharnois formation early to middle ibexian correlative strata of the philipsburg group include the wallace creek and morgan corner formations which represent outer platform sediments the coarse grained sandstone of the theresa formation accumulated in the innermost platform whereas coarse grained carbonates of the ogdensburg member indicate open marine subtidal to intertidal carbonate sand shoals by late ibexian the platform developed a pronounced margin where thrombolites flourished under high energy conditions these are represented by the thrombolite rich hasting creek and naylor ledge formations of the philipsburg group consequently a broad lagoon formed on the lee side of the platform margin where low energy conditions prevailed and accumulation of burrow mottled dolostones of the huntingdon member of the upper beauharnois formation took place the lagoon became more restricted during the latest stages of the basin fill whiterockian and high intertidal to supratidal sediments of the carillon formation were deposited

a new fossil vent biota in the ballynoe barite deposit silvermines ireland evidence for intracratonic sea floor hydrothermal activity about 352 ma considerable controversy exists as to the timing of the important mississippian carbonate hosted irish type zn pb ba ag deposits the silvermines deposits have been defined as an end member of this style in that they have been interpreted to display textures indicative of sea floor deposition one of the strongest arguments in favor of this interpretation was the report of a hydrothermal vent field including pyritic chimneys in the ballynoe open pit barite deposit this paper adds to that body of evidence by describing a hydrothermal vent fauna from the same vent field consisting of a delicately pyritized worm tube hosted by massive pyrite and hematized filaments of apparent microbial origin the worm tube is remarkably similar to fossil worm tubes from modern and ancient volcanic hosted massive sulfide deposits and the filamentous microfossils have similarities to modern fe oxidizing bacteria we have found no correlation between the worm tube and normal mississippian fossils such as crinoids whose replacement by pyrite in the immediately underlying ballynoe footwall destroys original morphology the sulfur isotope composition of the worm tube and host pyrite is essentially identical to that of the vent field pyrite and the main sulfide ore stage of silvermines sulfides all having a mean value about 20 per mil indicating an open system bacteriogenic sulfide source these discoveries provide additional evidence for the exhalative nature of parts of the silvermines orebodies and imply that mineralization had begun in the irish ore field by the late tournaisian 352 ma

the onset of the permo carboniferous glaciation reconciling global stratigraphic evidence with biogenic apatite δ18o records in the late visean the 18 o values of phosphatic microfossils recovered from nw ireland are used to determine the timing and magnitude of cooling associated with the onset of the carboniferous glaciation microfossil fish 18 o apatite demonstrates a 2 4 v smow shift which once corrected for 18 o seawater changes owing to evolving ice volumes equates to an approximate 4 5 c reduction in equatorial sea surface temperature between the earliest asbian and the mid brigantian late visean both conodont and microfossil fish 18 o apatite indicate stabilization of an icehouse climate during the brigantian and into the serpukhovian substantial late visean cooling identified herein is in good agreement with global glacioeustatic records supplementary material further information on the palaeogeography lithostratigraphy and palaeoenvironments of the sections examined as well as the sample composition and analytical methods of oxygen isotope analyses is available at http www geolsoc org uk sup18511

depth dependence of wind driven broadband ambient noise in the philippine sea in 2009 as part of philsea09 the instrument platform known as deep sound was deployed in the philippine sea descending under gravity to a depth of 6000 m where it released a drop weight allowing buoyancy to return it to the surface on the descent and ascent at a speed of 0 6 m s deep sound continuously recorded broadband ambient noise on two vertically aligned hydrophones separated by 0 5 m for frequencies between 1 and 10 khz essentially all the noise was found to be downward traveling exhibiting a depth independent directional density function having the simple form cos where 90 is the polar angle measured from the zenith the spatial coherence and cross spectral density of the noise show no change in character in the vicinity of the critical depth consistent with a local wind driven surface source distribution the coherence function accurately matches that predicted by a simple model of deep water wind generated noise provided that the theoretical coherence is evaluated using the local sound speed a straightforward inversion procedure is introduced for recovering the sound speed profile from the cross correlation function of the noise returning sound speeds with a root mean square error relative to an independently measured profile of 8 2 m s

geochemical evolution of produced waters from hydraulic fracturing of the marcellus shale northern appalachian basin a multivariate compositional data analysis approach abstract multivariate compositional data analysis methods were used to investigate geochemical data for water injected during hydraulic fracturing and for water produced from 19 marcellus shale gas wells in the northern appalachian basin the data were originally published as part of an industry report the analysis was adapted to consider the compositional nature of the data and avoid potentially spurious correlations present in raw concentration data through the application of log ratio transformations techniques such as robust variation arrays robust principal component analysis and relative variation plots were applied to log ratio transformed data results from this battery of multivariate tools indicate that two primary processes affect the chemical evolution of the water returned to the surface during the first 90 days of production mixing of injected water with formation brines of evaporated paleoseawater origin and injection of sulfate rich water during hydraulic fracturing may stimulate sulfate reduction at some sites spatial variability in sulfate alkalinity ratios appears to influence variations in geochemical controls on strontium versus barium with elevated proportions of strontium being found in more bicarbonate poor environments while barium is a larger proportion in sulfate poor areas comparison of results using a log ratio approach versus the more common analysis of concentration data reveals both similarities and some marked differences in the resulting interpretations results from this work are important in terms of both demonstrating methods to avoid mathematical inconsistencies from using raw brine geochemical data and to further investigate the geochemical controls on produced waters generated from shale gas reservoirs

the formation and failure of natural dams of the numerous kinds of dams that form by natural processes dams formed from landslides glacial ice and late neoglacial moraines present the greatest threat to people and property landslide dams form in a wide range of physiographic settings the most common types of mass movements that form landslide dams are rock and debris avalanches rock and soil slumps and slides and mud debris and earth flows the most common initiation mechanisms for dam forming landslides are excessive rainfall and snowmelt and earthquakes landslide dams can be classified into six categories based on their relation with the valley floor type i dams 11 of 184 landslide dams from around the world that we were able to classify do not reach from one valley side to the other type ii dams 44 span the entire valley floor in some cases depositing material high on opposite valley sides type iii dams 41 move considerable distances both upstream and downstream from the landslide failure type iv dams 1 are rare and involve the contemporaneous failure of material from both sides of a valley type v dams 1 also are rare and are created when a single landslide sends multiple tongues of debris into a valley and forms two or more landslide dams in the same reach of river type vi dams 3 involve one or more failure surfaces that extend under the stream or valley and emerge on the opposite valley side many landslide dams fail shortly after formation in our sample of 73 documented landslide dam failures 27 of the landslide dams failed less than 1 day after formation and about 50 failed within 10 days over topping is by far the most common cause of failure the timing of failure and the magnitude of the resulting floods are controlled by dam size and geometry material characteristics of the blockage rate of inflow to the impoundment size and depth of the impoundment bedrock control of flow and engineering controls such as artificial spill ways diversions tunnels and planned breaching by blasting or conventional excavation glacial ice dams can produce at least nine kinds of ice dammed lakes the most dangerous are lakes formed in main valleys dammed by tributary glaciers failure can occur by erosion of a drainage tunnel under or through the ice dam or by a channel over the ice dam cold polar ice dams generally drain supraglacially or marginally by downmelting of an outlet channel warmer temperate ice dams tend to fail by sudden englacial or subglacial breaching and drainage late neoglacial moraine dammed lakes are located in steep mountain areas affected by the advances and retreats of valley glaciers in the last several centuries these late neoglacial dams pose hazards because 1 they are sufficiently young that vegetation has not stabilized their slopes 2 many dam faces are steeper than the angle of repose 3 these dams and lakes are immediately downslope from steep crevassed glaciers and near vertical rock slopes and 4 downstream from these dams are steep canyons with easily erodible materials that can be incorporated in the flow and increase flood peaks the most common reported failure mechanism is overtopping and breaching by a wave or series of waves in the lake generated by icefalls rockfalls or snow or rock avalanches melting of ice cores or frozen ground and piping and seepage are other possible failure mechanisms natural dams may cause upstream flooding as the lake rises and downstream flooding as a result of failure of the dam although data are few for the same potential energy at the dam site ownstream flood peaks from the failure of glacier ice dams are smaller than those from landslide moraine and structed earth fill and rock fill dam failures moraine dam failures appear to produce some of the largest downstream flood peaks for potential energy at the dam site greater than 1011 1012 joules differences in flood peaks natural dam failures appear to be controlled by dam characteristics and failure mechanisms

occurrence of palygorskite and sepiolite in upper paleocene middle eocene marine deep sediments of the lagonegro basin southern apennines italy paleoenvironmental and provenance inferences abstract a mineralogical and geochemical study of clay lithologies and a biostratigraphic analysis of the carbonates from the deep sea lagonegro basin southern apennines italy have been carried out to deduce in general the provenance of clay sediments and their paleoenvironmental conditions and particular to recognize the signature of the paleocene eocene climatic global warming the analysed succession comprising a wide stratigraphic interval of the sannio unit spanning between albian to the upper oligocene lower miocene is exposed near accettura and stigliano villages eighteen clay samples were analysed by xrd xrf sem tg dta their age was framed by biostratigraphic analyses carried out on carbonate sediments mineral assemblage of the clay sediments includes quartz carbonates calcite and dolomite feldspars plagioclase and k feldspars hematite randomly illite smectite mixed layers with a low illite percentage kaolinite discrete illite muscovite chlorite palygorskite and sepiolite the low illite percentage in randomly illite smectite mixed layers indicates low diagenetic conditions for the studied successions these features are unique for the cretaceous tertiary successions of the lagonegro domain and are particularly significant for the preservation of the native mineralogical assemblage useful to determine the provenance and paleoenvironmental conditions of the clayey sediments palygorskite and sepiolite are concentrated in the upper paleocene middle eocene stratigraphic interval and particularly in the upper part of the early eocene lower part of the middle eocene biozone of blow p 9 12 clay sediments rich in palygorskite and sepiolite show a higher p 2 o 5 amount and a lower kaolinite percentage compatible with warm and arid climatic conditions typical of the global warming event well recorded in the southern tethyan margin likely palygorskite and sepiolite formed in lagoonal environment in nearby carbonate platform margins and then they were transported into the lagonegro basin as indicated by the well developed habitus of palygorskite during the paleogene the lagonegro basin and the nearby carbonate platforms represented a key sector the southern paleodomains of the tethys the discovery of these minerals gives a contribution to the reconstruction paleoenvironmental conditions of the tethian paleo margin during the early middle eocene

natural and anthropogenic factors affecting groundwater quality of an active volcano mt etna italy abstract new geochemical data on dissolved major and minor constituents in 276 groundwater samples from etna aquifers reveal the main processes responsible for their geochemical evolution and mineralisation this topic is of particular interest in the light of the progressive depletion of water resources and groundwater quality in the area multivariate statistical analysis reveal 3 sources of solutes a the leaching of the host basalt driven by the dissolution of magma derived co2 b mixing processes with saline brines rising from the sedimentary basement below etna c contamination from agricultural and urban wastewaters the last process highlighted by increased concentrations of so4 no3 ca f and po4 is more pronounced on the lower slopes of the volcanic edifice associated with areas of high population and intensive agriculture however this study demonstrates that natural processes a and b are also very effective in producing highly mineralised waters which in turn results in many constituents b v mg exceeding maximum admissible concentrations for drinking water

hydrothermal water rock interaction and the redistribution of li b and cl in the taupo volcanic zone new zealand abstract lithium b and cl occur as trace elements in the dominant protoliths rhyolite andesite and greywacke underlying high temperature hydrothermal systems in the taupo volcanic zone tvz the fluid mobility of li decreases substantially at 200 c 20 c with the pervasive deposition of quartz chlorite regardless of protolith and altering fluid compositions boron and cl are more fluid mobile than li at all temperatures with mobility affected by the rock type composition of circulating aqueous solutions and to a limited extent by incorporation of the trace elements in hydrothermal minerals uptake of b by clays decreases its mobility at 320 c occur compared to volcanic rocks the mobility of b and cl in greywackes is very low and thus the b cl signature of greywacke in hydrothermal aqueous solutions of the tvz is overwhelmed by the effects of rhyolite and andesite dissolution temperature dependent transitions from mg fe clays and phyllosilicates to k bearing illitic clays tend to decrease the mg li ratios in aqueous solutions at 200 c

ranging bowhead whale calls in a shallow water dispersive waveguide this paper presents the performance of three methods for estimating the range of broadband 50 500 hz bowhead whale calls in a nominally 55 m deep waveguide conventional mode filtering cmf synthetic time reversal str and triangulation the first two methods use a linear vertical array to exploit dispersive propagation effects in the underwater sound channel the triangulation technique used here while requiring no knowledge about the propagation environment relies on a distributed array of directional autonomous seafloor acoustics recorders dasars arranged in triangular grid with 7 km spacing this study uses simulations and acoustic data collected in 2010 from coastal waters near kaktovik alaska at that time a 12 element vertical array spanning the bottom 63 of the water column was deployed alongside a distributed array of seven dasars the estimated call location to array ranges determined from cmf and str are compared with dasar triangulation results for 19 whale calls the vertical array ranging results are generally within 10 of the dasar results with the str results providing slightly better agreement the results also indicate that the vertical array can range calls over larger ranges and with greater precision than the particular distributed array discussed here whenever the call locations are beyond the distributed array boundaries

statistical estimation of transmission loss from geoacoustic inversion using a towed array geoacoustic inversion estimates environmental parameters from measured acoustic fields e g received on a towed array the inversion results have some uncertainty due to noise in the data and modeling errors based on the posterior probability density of environmental parameters obtained from inversion a statistical estimation of transmission loss tl can be performed and a credibility level envelope or uncertainty band for the tl generated this uncertainty band accounts for the inherent variability of the environment not usually contained in sonar performance prediction model inputs the approach follows gerstoft et al ieee j ocean eng 31 299 307 2006 and is demonstrated with data obtained from the mapex2000 experiment conducted by the nato undersea research center using a towed array and a moored source in the mediterranean sea in november 2000 based on the geoacoustic inversion results the tl and its variability are estimated and compared with the measured tl

a laboratory study of the expansion of an irish pyritic mudstone siltstone fill material abstract extensive damage to dwellings in the east of ireland arising from the expansive pyritic fill material used beneath the floor slabs prompted the laboratory study presented in this paper to quantify the expansion and study its influencing factors a novel experimental arrangement in which sample height and water supply were varied was used to test a large quantity of active pyritic infill taken from an affected house in the greater dublin area the expansion of ten separate fill specimens was measured over a 175 day period from december 2010 to may 2011 remarkably consistent results were obtained when the expansions were normalised by the sample height with expansion rates of approximately 2 3 mm year m height of fill for specimens standing in water where the rates were largely insensitive to the amount of water supplied more rapid expansion was noted for one specimen to which no additional water was supplied during the test a steady reduction in ph of the water although relatively small was consistent with pyrite oxidation reactions occurring in the samples during the test and also implies the occurrence of leaching of ions from the pores in the mudstone and also that oxidation reactions may have been occurring in the saturated mudstone changes in expansion were found also to correlate strongly with changes in the ambient temperature in all specimens

the combined use of masw and resistivity surveys for levee assessment a case study of the melvin price reach of the wood river levee abstract capacitively coupled resistivity ccr and multichannel analysis of surface waves masw were performed on the melvin price reach of the wood river levee that has experienced considerable piping through the foundation soil causing numerous sand boils along the landside toe of the levee tests were performed along the centerline crest the landside toe and the riverside berm of the levee this study combined the strengths of masw and ccr testing to resolve the distribution and stiffness of cohesive and non cohesive materials in the body and foundation of the levee where invasive testing was not ideal masw and ccr were shown to complement each other in the evaluation ccr successfully classified the near surface clay and sand deposits along the levee and was particularly effective for soil deposits with a high degree of saturation masw revealed that a deeper clay layer appears to be discontinuous at locations where old river bars cross under the levee these bars may have eroded portions of the deeper clay layer locally enhancing seepage rates through the foundation materials and influencing the formation of sand boils during large flood events the use of masw and ccr also successfully detected the locations of the major utilities crossing the levee while ccr was the most effective method for detecting conductive utilities masw was more effective at detecting utilities which increased the overall stiffness of the subsurface either due to the utility itself or the backfill material around the utility a site specific spt vs correlation was developed from the co located boreholes and shear wave velocity profiles comparison of the correlation with previous studies indicates that soil stiffness and geologic age are important factors affecting spt vs correlations for levee soil deposits which are typically young a lower bound spt vs correlation developed using similar soil deposits to the study area should be considered

desiccation of a sensitive clay field experimental observations an excavation with three different levels was exposed to continuous evaporation during 35 days in order to observe and document the formation of shrinkage cracks in an intact and weathered sensitive marine clay desiccation of the intact saint alban clay under restrained conditions at an average evaporation rate of 0 018 cm h and an initial moisture content of 103 produced visible primary cracks after 17 h with an average spacing of 20 to 24 cm secondary cracks within each original polygon appeared after about 70 h of evaporation subhorizontal cracks at a depth of 6 to 8 cm were also created owing to differential strains induced by differential shrinkage of the soil polygons further evaporation resulted in the formation of a new set of vertical cracks after about 150 h of evaporation in the soil below the subhorizontal shear plane the shrinkage induced volume change associated with these different sets of cracks produced polygons with a protuberance at their bottom part indicating that the depth of crack propagation below the subhorizontal shear plane was about 3 to 4 cm in weathered clay at an initial moisture content of about 50 the average spacing was 10 to 12 cm indicating that spacing between primary cracks is related to soil type in the cohesionless topsoil no cracks were observed

passive bottom reflection loss estimation using ship noise and a vertical line array an existing technique for passive bottom loss estimation from natural marine surface noise generated by waves and wind is adapted to use noise generated by ships the original approach based on beamforming of the noise field recorded by a vertical line array of hydrophones is retained however additional processing is needed in order for the field generated by a passing ship to show features that are similar to those of the natural surface noise field a necessary requisite is that the ship position relative to the array varies over as wide a range of steering angles as possible ideally passing directly over the array to ensure coverage of the steepest angles the methodology is illustrated through simulation and applied to data from a field experiment conducted offshore of san diego ca in 2009

tomographic inversion for sediment parameters in shallow water this article discusses inversions for bottom geoacoustic properties using broadband acoustic signals obtained from explosive sources the experimental data used for the inversions are sus charge explosions acquired on a vertical hydrophone array during the shelf break primer experiment conducted south of new england in the middle atlantic bight in august 1996 the sus signals were analyzed for their time frequency behavior using wavelets the group speed dispersion curves were obtained from the wavelet scalogram of the sus signals a genetic algorithm ga was used for the inversion of sound speeds in the water column and compressional wave speeds in the sediment layers the variations in the sound speeds in the water column were represented using empirical orthogonal functions eofs a range independent normal mode routine was used to construct the replica fields corresponding to the parameters comparison of group speeds for modes 1 to 9 and for a range of frequencies 8 to 200 hz was used to arrive at the best parameter fit an efficient hybrid optimization scheme using the ga and a levenberg marquardt algorithm is presented linear perturbation methods were also used to fine tune the inversions and to obtain resolution and variance estimates analysis was also done to compute the degree of convergence of each of the parameters by explicitly calculating the hessian matrices numerically a posteriori estimation of mean and covariance was also done to obtain error estimates group speeds for the inverted sound speed fields provide an excellent match to the experimental data the inverted sediment compressional speed profile compares well with in situ measurements

gpr detection of several common subsurface voids inside dikes and dams ground penetrating radar gpr technique has been used in detecting several common subsurface voids inside dikes and dams in south of china and the results indicate that gpr can be successfully applied to uncovering termite nests inside dikes and dams and the technique proves to be advantageous in real time retrieval of detection data precise positioning and effect of application being basically not affected by locality and climate when it is compared to other available methods gpr is also effective in detecting cracks in the sloping clay core and proves to pose less impact on the normal operation of the detected hydraulic projects be more efficient and capable of retrieving more comprehensive detection data when compared with the method of artificial observation through holes chiseled out from the ground also gpr is capable of detecting ferralsol in tropical and subtropical regions to some depth and shows high value of application in detecting some hidden troubles such as caves and settlements with low to moderate depths inside dams in karst regions moreover gpr technique proves to be so capable of detecting carbonate rocks to certain depth and can yield precise results that it can be applied to analysis and discovery of leakage channels inside reservoirs in karst regions

residence time indicators in groundwater the east midlands triassic sandstone aquifer the east midlands triassic sherwood sandstone aquifer which has been the subject of detailed radiometric age studies is used to investigate both inert and reactive constituents of groundwater as indicators of residence time detailed resampling of the aquifer in 1992 has provided a considerable body of new inorganic geochemistry data though without radiocarbon several inert indicators are defined including the isotopic ratios 18o 2h 36cl noble gas ratios as well as the halogen elements cl br f i and their element ratios these form a group of essentially unreactive tracers primarily reflecting changing rainfall inputs and palaeoclimatic conditions except at outcrop where human impacts are also seen clearly the concentrations of cl mainly from atmospheric sources remain below 25 mg l 1 cl over a distance of some 30 km from outcrop reactive indicators the result of time dependent water rock interactions include 13c mg ca sr ca na cl and show diagnostic trends along the flow lines however the concentrations of certain trace elements li rb cs mn and mo which are not limited by solubility constraints show linear trends along the present day flow gradient this water rock interaction is taking place in groundwaters with low total mineralisation and it can be demonstrated that reactions involving these elements and isotopes are occurring entirely within the aquifer since high salinity groundwaters are found below the sherwood sandstone there is good correlation between some of the elements and 14c activities in the 1977 data set and this has been used to derive a concentration age relationship for the 1992 set of data a chemical timescale for the aquifer is then established using a li and b a combination of five trace elements the age of the fresh groundwater is thus shown to be up to 100 ka bp indicating the likelihood of semi continuous recharge during the devensian glacial period preceding the glacial maximum when no recharge occurred 10 20 ka bp this approach may be of value in extending groundwater dating beyond the radiocarbon timescale as well as interpreting sites where no radiocarbon data are available the scatter from the mean age line indicates those groundwaters which are derived from either rapid or slower than average flow zones within the aquifer as well as age stratification this stratification is borne out by a depth profile of groundwater from a new borehole near to outcrop which is shown by a combination of chemical and isotopic tracers to contain holocene overlying late pleistocene water

mineral alteration and genesis of al rich soils derived from conglomerate deposits in cabo basin ne brazil abstract in the cabo basin ne brazil conglomerates have given rise to soils with attributes that are rarely observed in humid tropical climates and remain relatively unknown within the scientific community these soils have high levels of al in the exchangeable phase diminishing their agricultural and environmental potential in an underdeveloped region of great socioeconomic importance this paper presents the mineralogy and genesis of soils derived from conglomerates on a slope in the cabo basin with the aim of meeting the demand for studies on al rich soils three soils were classified morphologically described and sampled for the accomplishment of chemical physical and mineralogical analyses including the main exchangeable cations content mineralogy of the sand silt and clay fraction differentiation of the fe and al forms mineral micromorphology and chemical composition of mineral species in addition chemical and physical attributes were used in multivariate analyses the soil mineralogy is associated with the weathering evolution of three mineralogical zones identified in the cr horizons pathways of alteration followed by feldspars and micas resulted in kaolinite smectite and hydroxy al interlayered smectite formation argilification the susceptibility of the conglomerate to weathering constant releases of al from the structure of aluminous minerals low contents of exchangeable bases and consequent low ph values

column on column structures as indicators of lava ice interaction ruapehu andesite volcano new zealand abstract lava flows of the mangawhero formation ca 15 60 ka on ruapehu volcano erupted during the last glaciation in a distal flow lobe at tukino on the east side of the mountain small secondary columns 10 20 cm thick have formed on the sides of large rectangular primary 0 5 3 m thick cooling columns thick 10 m zones of such small columns form a lateral and basal outer rind of the lobe as they do not mark glassy zones of quenching these secondary columns are interpreted as being formed by a second cooling event at temperatures below the boundary between the low creep and elastic regimes 600 c by rapid influx of copious amounts of water temperature drops deduced from extensional strains of the two sets of columns were used to gauge the viability of such a two stage process absence of reliable data on andesite contraction coefficients was overcome by using a sliding scale to assess a large range of values the estimates indicate that two stage chilling is feasible after flowing across relatively ice poor terrain the lava flow must have interacted with a valley glacier that provided water for further chilling the already formed primary columns and formation of the outer rind small columns given this evidence for lava ice interaction it is likely that prominent thick flows elsewhere in the mangawhero formation may have been constrained to their ridge top locations by ice conditions similar to those described by lescinsky and sisson lescinsky d t sisson t w 1998 ridge forming ice bounded lava flows at mount rainier washington geology 26 351 354

compositional multivariate statistical analysis of the hydrogeochemical processes in a fractured massif la linea tunnel project colombia abstract hydrogeochemical and isotopic data were used to improve the understanding of 1 groundwater flow in a complex fractured aquifer system 2 surface water groundwater interactions and 3 groundwater evolution within the la linea massif in the cordillera central of the colombian andes using two roadway tunnels drilled there as a natural laboratory the la linea massif is a crystalline structure formed by two igneous metamorphic fractured complexes cajamarca group and quebradagrande group plus andesitic porphyry rocks from the cenozoic period the tunnels traverse eight main fault zones where higher infiltrations of groundwater into the tunnels were reported water samples were collected at the surface and within the tunnels in three different sampling rounds in 2010 2014 and 2015 major ion concentrations and 18 o and 2 h stable isotopic ratios were measured this database is a unique opportunity to investigate water rock interaction processes through time in a dewatering crystalline rock massif in such an important area in the colombian andes compositional data analysis coda techniques were implemented on the major ion data before a multivariate statistical analysis msa the msa included a compositional principal component analysis pca and a compositional hierarchical cluster analysis hca combined with more classical graphical methods for the classification of water chemistry data such as piper and stiff diagrams according to the compositional hca and pca the obtained components and clusters are first related to the location of the samples surface or tunnel samples followed by the geochemical processes the geochemical variability of the massif is associated with the weathering of silicates and pyrite oxidation that generates carbonate dissolution as a result of the drainage caused by the tunnels a temporal evolution characterized by a decrease in ph conductivity and mg2 concentrations was observed the analysis of the stable isotopes 2h and 18o suggests that the sampled groundwater has a common origin recharge waters with specific signatures for the east and west watersheds that exhibit alterations due to hydration because of the dissolution of plagioclases and rock water interactions with materials exposed to hydrothermal fluids

mapping of leakage paths in damaged embankment using modified resistivity array method abstract the cause and path of leakage in a damaged embankment in korea were interpreted through integrated 3 d resistivity inversion data from a modified electrical resistivity survey were analyzed for cross potential array direct potential array and d lux array these proposed modified arrays used line source point source and borehole source for data acquisition in the embankment the modified electrical resistivity survey is a method to predict the path of a leakage by connecting the regions where the current flow gathers and the potential difference is reduced when the current flows through the embankment therefore this method takes the potential differences as data and calculates the potential distribution for the target area to interpret the path of the current flow analysis of the modified survey data revealed the existence of two zones suspected of leakage in the downstream slope one region was identified as an end drainage pipe and the other was the right abutment where the leakage occurred the 3 d inversion model was built through modified electrical resistivity tomography in the 3 d model the resistivity anomaly at the right abutment matched a low resistivity zone in the modified survey data and it means that the results of traditional 3 d survey support those of the modified electrical resistivity survey for reliability of interpretation we verified the findings based on the evidence of actual leakage on the embankment surface through comparative analysis the cause and route of leakage of the fill dam could be predicted and verified

human impact on regional groundwater composition through intervention in natural flow patterns and changes in land use schot p p and van der wal j 1992 human impact on regional groundwater composition through intervention in natural flow patterns and changes in land use j hydrol 134 297 313 the relations between groundwater composition land use soil conditions and flow patterns on a regional scale are studied for the gooi and vechtstreek area in the netherlands this densely populated area consists of a glacier created ridge with dry sand soils bordered by the vecht and eem river plains with wet peat and clay soils r mode factor analysis and q mode cluster analysis were applied to a set of 1349 groundwater analyses to determine the factors controlling groundwater composition and the main resulting water types the results indicate that groundwater composition in the study area is affected on a regional scale by human activities through changes in land use and intervention in natural flow patterns on the ridge ground water is recharged by precipitation which dissolves carbonates from the matrix of the sandy aquifer increased solute concentrations in shallow ground water especially of nitrate sulphate and potassium indicate increased pollution resulting from urbanization and increasingly intensive agricultural activity over the past decades in the vecht river plain infiltration occurs as a result of drainage of polders and groundwater extraction on the ridge recharge occurs by precipitation and from polluted surface water to which ammonium organic complexes and carbonic acid are added through decomposition of organic matter in the peat and clay soils the carbonic acid results in enhanced dissolution of carbonates present in the soil and the underlying sandy aquifer oxygen depletion and subsequent low redox potentials result in denitrification dissolution of manganese and iron oxides and sulphate ro duction the flow of ground water from high level to low level polders causes displacement of a former stagnant brackish groundwater body under the vecht river plain accompanied by increased mixing of fresh and brackish ground water

engineering geological assessment of the proposed urus dam turkey abstract this paper describes the results of the engineering geological investigations and rock mechanics studies carried out at the proposed urus dam site analyses were carried out in terms of rock mass classifications for diversion tunnel kinematic analysis of excavation slopes permeability of the dam foundation and determination of rock mass strength parameters urus dam is a rock filled dam with upstream concrete slab the dam will be built on the suveri river in the central part of turkey the foundation rocks are volcanic rocks which consist of andesite basalt and tuff of neogene age studies were carried out both at the field and the laboratory field studies include engineering geological mapping intensive discontinuity surveying core drilling pressurized water tests and sampling for laboratory testing uniaxial triaxial and tensile strength tests were performed and deformation parameters unit weight and porosity were determined on the intact rock specimens in the laboratory rock mass strength and modulus of elasticity of rock mass are determined using the hoek brown empirical strength criterion rock mass classifications have been performed according to rmr and q systems for the diversion tunnel engineering geological assessment of the proposed dam and reservoir area indicated that there will be no foundation stability problems detailed geotechnical investigations are required for the final design of the dam

performance assessment of a short hydrophone array for seabed characterization using natural made ambient noise the passive acoustic estimate of seabed properties using natural made ambient noise received on a glider equipped hydrophone array provides the capability to perform long duration seabed characterization surveys on demand in denied areas however short and compact arrays associated with gliders are limited to a few hydrophones and small aperture consequently these arrays exhibit lower resolution of the estimated seabed properties and the reliability of the environmental estimates may be questionable the objective of the nato sto cmre sea trial rep14 med conducted west of sardinia mediterranean sea is to evaluate the performance of a prototype glider array with eight hydrophones in a line and variable hydrophone spacing for seabed characterization using natural made ambient noise this prototype array is deployed vertically above the seabed together with a 32 element reference vertical line array the arrays are moored at different sites with varying sediment properties and stratification the seabed reflection properties and layering structure at these sites are estimated from ambient noise using both arrays and the results are compared to assess the glider array performance synthetic extension of the glider array is performed to enhance resolution of the bottom properties and the results are compared with these from the longer reference array

geochemical and statistical evidence of deep carbonate groundwater within overlying volcanic rock aquifers aquitards of southern nevada usa abstract samples collected from springs and wells in southern nevada were analyzed for major solutes and trace elements as part of a larger study to characterize the geochemical signatures of these groundwaters in this study principal component analysis pca was used to reduce the large data sets including the four major cations ca mg na k and 27 trace elements analyzed in these groundwater samples principal components analysis of the major cation data indicates that groundwaters from cenozoic felsic volcanic rock aquifers aquitards of southern nevada exhibit strong chemical associations to each other but weak relationships to groundwaters from the regional carbonate aquifer which were instead chemically similar to each other however pca of the trace element data demonstrates that some groundwaters from the volcanic aquifers aquitards are chemically similar to those of the underlying regional carbonate aquifer the pca also reveals that these groundwaters from the volcanic aquifers aquitards have significantly different trace element compositions than perched groundwaters contained within similar felsic volcanic rocks moreover rare earth element ree data from groundwaters collected from wells finished in the volcanic aquifers aquitards of southern nevada have similar concentrations and similar shale normalized patterns to the carbonate aquifer groundwaters as well as local carbonate rocks these same southern nevada well waters do not exhibit ree concentrations or shale normalized signatures that resemble the perched volcanic groundwaters or the tuffs of southern nevada the ree data and trace element pca along with previous carbon isotope analyses water temperature data hydraulic head relations and results of a recent pump test of a well near yucca mountain suggest close contact of the regional carbonate groundwaters and groundwaters from the overlying volcanic rocks of southern nevada and possible upwelling of the carbonate groundwaters into the overlying volcanic rock units in the vicinity of yucca mountain

identification of leakage and potential areas for internal erosion combining ert and ip techniques at the negratin dam left abutment granada southern spain abstract at the negratin dam southern spain two main springs derived from the water reservoir were detected on the west side of the mountain ridge matching the location of the left abutment of the dam the seepages appear when the level of the stored water exceeds 622 m above sea level m a s l where some paleochannels are embedded in the silts the water level was at 631 m a s l on the day of the measurements 13 12 23 close to the historical maximum 633 78 m a s l although the water crossing the leaks does not drag particles nowadays this sector may potentially cause internal erosion or piping phenomena implying a loss of water resources and slope instability problems the infiltration areas were evaluated by electrical resistivity and induced polarization methods measured along one profile on the mountain ridge between the water reservoir and the springs we determine that the infiltrations zones are characterized by low resistivity and high chargeability distributed in small areas we demonstrate that these methods are a reliable tool to detect and characterize infiltration zones and they are the first step to planning mitigation actions to avoid the piping phenomena

origin and evolution of sarinena lake central ebro basin a piping based model abstract the origin and nature of the numerous lakes in the central ebro basin have been interpreted according to the prevailing arid or semiarid conditions the easily eroded materials and the solubility of the gypsum and or carbonate rich tertiary cenozoic substratum involving important dissolution karstic and or aeolian deflation however the origin of sarinena lake the largest in the central ebro basin remains unknown since the typical lake generating processes in the region are not applicable this work provides significant clues to the genesis and evolution of sarinena lake in a regional context the combination of geomorphological mapping and high resolution lidar data together with sedimentological observations the characterisation of soils and sediments around the lake and the application of high resolution geophysical techniques suggest that piping is the major genetic process driving the evolution of the sarinena depression and lake field evidence demonstrates that piping is at present the most important erosive process in the region generating significant collapse and surface lowering sarinena lake is located within a deep endorheic depression excavated from na rich tertiary materials this work hypothesises that once an early fluvially originated palustrine area had developed the progressive lowering of the regional water table linked to regional fluvial incision favoured the establishment of a hydrological gradient high enough to trigger piping processes within the claystones and siltstones underlying the original palustrine area the quaternary evolution of the sarinena lacustrine basin was then controlled by successive water table fluctuations linked to different phases of incision and alluvial deposition in the surrounding fluvial systems all the evidence supporting a piping related origin for this lake together with examples of lakes generated by similar processes in different contexts is used to propose a new genetic type of lacustrine depression generated by piping processes under favourable conditions

chemical mass transfer during hydrothermal alteration of carbonates controls of seafloor subsidence sedimentation and zn pb mineralization in the irish carboniferous abstract petrographic and geochemical data were acquired to evaluate models for the formation of hydrothermal dolomite breccias that host zinc lead orebodies in the rathdowney trend of the irish orefield and assess element mobility during hydrothermal alteration of carbonates macroscopic and microscopic textures indicate that the breccias largely formed by a pseudobrecciation process involving dissolution and replacement of precursor waulsortian dolomite of diagenetic origin during subseafloor hydrothermal fluid flow geochemical analyses show that compared with the waulsortian dolomite precursor breccia clasts and matrix contain respectively higher concentrations of al ti and light rare earth elements which are linearly correlated indicative of mass loss during hydrothermal interaction bulk rock mass loss estimates average 33 indicating extensive dissolution of carbonate although petrographic evidence and limited clast rotation or translation rule out the development of significant open space this supports a mechanism of alteration whereby hydrothermal fluids migrating along grain boundaries microcracks and solution seams drove dissolution and replacement of the surrounding host rock with partial collapse of the transient microporosity produced progressive interaction led to the gradual isolation of domains clasts surrounded by replacement dolomite matrix massive sulfide mineralization formed subsequently by stratabound replacement of the dolomite pseudobreccia by hydrothermal fluids preferentially focused within the more permeable and possibly more reactive lithology this process involved further volume loss 30 of the replaced rock quantitative mass transfer analysis indicates that during hydrothermal interaction net loss of na p mn sr and sometimes cu and net gain in li k fe as well as the ore associated elements typically occurred marked fractionation of the ree is observed eu was added implicating elevated temperature acidic and reduced hydrothermal fluids ce was also added possibly derived from remobilization of pre sulfide oxide mineralization the lree were typically immobile or partially removed and the hree were preferentially mobilized and transported beyond the scale of sampling thus the hree together with na p mn sr and possibly cu may form a distal chemical anomaly at the base of the waulsortian limestone formation the net addition of li k and be in dolomite breccia matrix samples combined with their increase in concentration due to dolomite dissolution produced a broad anomaly of these elements extending for at least 1 5 km from the center of the lisheen deposit these various geochemical anomalies have potential utility in mineral exploration a total volume loss of up to 68 at lisheen is consistent with a marked thinning of the waulsortian biomicrite facies above massive sulfide the observed thickening of upper and supra waulsortian facies in the trough developed above this zone is interpreted to reflect infill of a seafloor depression up to 90 m deep developed in response to underlying hydrothermal dissolution this model implies mineralization initiated during the latter stages of waulsortian deposition in the late courceyan early chadian at a depth of approximately 150 m below the seafloor

engineering geological assessment of the obruk dam site corum turkey engineering geological properties of rock masses such as discontinuities degree of weathering strength and hydraulic conductivities along the dam axis and the excavatibility of diversion tunnels power tunnels and spillways were investigated in order to determine probable problems and necessary precautions to be taken prior to construction in this study the obruk dam site constructed on the kizilirmak river to the north of corum central anatolia was investigated from the standpoint of the aforementioned engineering geological aspects quaternary alluvium at the dam site has a thickness of about 65 m and overlies the eocene basalt basement diversion and power tunnels were constructed in the basalts in order to determine the distribution of the basalt both horizontally and vertically core samples were collected from preliminary geotechnical boreholes drilled by the general directorate of the state hydraulic works dsi and the depth to groundwater was measured in these boreholes the geological and geomechanical properties of the basalt are controlled by tectonism and weathering and these properties vary over short distances the mineralogical petrographical and geomechanical properties of the basalt core samples were determined based on these test results the rock mass cropping out at the dam site has been classified for tunneling and possible support systems suggested

surface and borehole geophysics for the rehabilitation of a concrete dam penne central italy abstract in this paper surface and borehole geophysical surveys are employed to improve the effectiveness of a rehabilitation intervention cut off wall to be executed on the right abutment of a leaking concrete dam penne central italy in a first step surface geophysical measurements electrical resistivity and p wave velocity data were collected to provide a geophysical model to be compared to the preliminary geological model available before the geophysical survey because significant differences emerged between the geophysical and the preliminary geological models a second phase of borehole investigations was planned to validate the geophysical reconstruction obtained from surface data the final geological model resulting from the geophysical results differs significantly from the preliminary model available at the time of the geophysical survey therefore the planned cut off wall needs to be extended both laterally and in depth beyond the position estimated before the geophysical campaign so that the low permeability bedrock is intercepted at a depth equal or lower than the critical one at the end the low cost geophysical campaign 1 5 of the entire costs of the intervention was highly beneficial to this project minimizing subsurface geological uncertainty to design an effective anti seepage intervention and stressing the importance of a representative geological model for engineering design

multivariate statistical analysis of geochemical data as indicative of the hydrogeochemical evolution of groundwater in a sedimentary rock aquifer system summary the study of groundwater hydrogeochemistry of the paleozoic basses laurentides sedimentary rock aquifer system in quebec produced a large geochemical dataset groundwater samples were collected at 153 sites over a 1500 km2 study area and analyzed for major and minor ions the large number of data can lead to difficulties in the integration interpretation and representation of the results two multivariate statistical methods hierarchical cluster analysis hca and principal components analysis pca were applied to a subgroup of the dataset to evaluate their usefulness to classify the groundwater samples and to identify geochemical processes controlling groundwater geochemistry this subgroup consisted of 144 samples and 14 parameters ca2 mg2 na k hco 3 cl so 4 2 fe2 mn2 br sr2 f ba2 hs seven geochemically distinct clusters c1 c7 resulted from the hca samples from clusters c3 c4 c6 and c7 are mostly located in preferential recharge areas the majority of these samples have ca mg hco3 recharge groundwater c3 c6 c7 and na hco3 evolved groundwater c4 samples from the other three clusters c1 c2 c5 are characteristic of an aquifer system under confined conditions the majority of these samples have na hco3 evolved groundwater c1 c5 and na cl ancient groundwater that exhibits elevated concentrations in br c2 in addition to recognizing the importance of hydrogeological conditions on groundwater geochemistry the distribution of clusters also showed the importance of the geological formations on minor and trace elements such as fe2 mn2 sr2 f and ba2 the first five components of the pca account for 78 3 of the total variance in the dataset component 1 is defined by highly positive loadings in na cl and br and is related to groundwater mixing with champlain sea water and solute diffusion from the marine clay aquitard the high positive loadings in ca2 and mg2 of component 2 suggest the importance of dissolution of carbonate rocks in this aquifer system from their characteristic loadings the first two components are defined as the salinity and hardness components respectively components 3 5 are related to more local and geological effects the integration of the hca and the pca with conventional classification of groundwater types as well as with the hydrogeological and geological contexts allowed the division of the region into four main geochemical areas providing an improved regional picture of the aquifer system dynamics and hydrogeochemical evolution of groundwater the following factors were recognized as influencing the evolution of groundwater identified in every geochemical area 1 geological characteristics including sedimentary rock type and till mineralogy 2 hydrogeological characteristics represented by the level of confinement and the hydraulic gradient and 3 the geological history including the latest glaciation and the champlain sea invasion with its integrated approach this hydrogeochemical study contributes to the characterization and understanding of complex groundwater flow systems and provides an example of the long term geochemical evolution of hydrogeological systems after a major perturbation in this case seawater invasion

rapid least squares inversion of apparent resistivity pseudosections by a quasi newton method1 a fast inversion technique for the interpretation of data from resistivity tomography surveys has been developed for operation on a microcomputer this technique is based on the smoothness constrained least squares method and it produces a two dimensional subsurface model from the apparent resistivity pseudosection in the first iteration a homogeneous earth model is used as the starting model for which the apparent resistivity partial derivative values can be calculated analytically for subsequent iterations a quasi newton method is used to estimate the partial derivatives which reduces the computer time and memory space required by about eight and twelve times respectively compared to the conventional least squares method tests with a variety of computer models and data from field surveys show that this technique is insensitive to random noise and converges rapidly this technique takes about one minute to invert a single data set on an 80486dx microcomputer

quantitative assessment of the flow pattern in the southern arava valley israel by environmental tracers and a mixing cell model abstract this paper demonstrates the implementation of a novel mathematical model to quantify subsurface inflows from various sources into the arid alluvial basin of the southern arava valley divided between israel and jordan the model is based on spatial distribution of environmental tracers and is aimed for use on basins with complex hydrogeological structure and or with scarce physical hydrologic information however a sufficient qualified number of wells and springs are required to allow water sampling for chemical and isotopic analyses environmental tracers are used in a multivariable cluster analysis to define potential sources of recharge and also to delimit homogeneous mixing compartments within the modeled aquifer six mixing cells were identified based on 13 constituents a quantitative assessment of 11 significant subsurface inflows was obtained results revealed that the total recharge into the southern arava basin is around 12 52 10 6 m 3 year 1 the major source of inflow into the alluvial aquifer is from the nubian sandstone aquifer which comprises 65 75 of the total recharge only 19 24 of the recharge but the most important source of fresh water originates over the eastern jordanian mountains and alluvial fans

towards more realistic values of elastic moduli for volcano modelling abstract the accuracy of elastic analytical solutions and numerical models widely used in volcanology to interpret surface ground deformation depends heavily on the young s modulus chosen to represent the medium the paucity of laboratory studies that provide young s moduli for volcanic rocks and studies that tackle the topic of upscaling these values to the relevant lengthscale has left volcano modellers ill equipped to select appropriate young s moduli for their models here we present a wealth of laboratory data and suggest tools widely used in geotechnics but adapted here to better suit volcanic rocks to upscale these values to the scale of a volcanic rock mass we provide the means to estimate upscaled values of young s modulus poisson s ratio shear modulus and bulk modulus for a volcanic rock mass that can be improved with laboratory measurements and or structural assessments of the studied area but do not rely on them in the absence of information we estimate upscaled values of young s modulus poisson s ratio shear modulus and bulk modulus for volcanic rock with an average porosity and an average fracture density quality to be 5 4 gpa 0 3 2 1 gpa and 4 5 gpa respectively the proposed young s modulus for a typical volcanic rock mass of 5 4 gpa is much lower than the values typically used in volcano modelling we also offer two methods to estimate depth dependent rock mass young s moduli and provide two examples using published data from boreholes within k lauea volcano usa and mt unzen japan to demonstrate how to apply our approach to real datasets it is our hope that the data and analysis presented herein will assist in the selection of elastic moduli for volcano modelling to this end we provide a microsoft excel spreadsheet containing the data and necessary equations to calculate rock mass elastic moduli that can be updated when new data become available the selection of the most appropriate elastic moduli will provide the most accurate model predictions and therefore the most reliable information regarding the unrest of a particular volcano or volcanic terrain

assessing preferential seepage and monitoring mortar injection through an earthen dam settled over a gypsiferous substrate using combined geophysical methods abstract for several decades the sant llorenc de montgai reservoir has experienced different problems that could affect the safety of the engineering structure for this reason several corrective actions have been taken over the years here we present a study involving complementary geophysical methods including electrical resistivity tomography seismic refraction tomography and frequency domain electromagnetic surveys the analysis of the inverted electrical resistivity tomography cross sections combined with the seismic refraction results and land subsidence monitoring data show the likely mechanism of abnormal seepage the areas where mortar injections were applied as a corrective measure are also clearly delineated in addition the evolution of the state of the embankment has been established from two successive electrical resistivity tomography surveys in the last two decades the results show areas where corrective mortar injections have been effective while in other areas new abnormal seepage has been detected the lithological heterogeneity of the bedrock especially the dissolution of gypsum rich rocks induced subsidence effects and caused abnormal seepage in different areas along the embankment our results indicate how corrective solutions can be optimized to reduce the cost of corrective engineering interventions

integrated geophysical approach in assessing karst presence and sinkhole susceptibility along flood protection dykes of the loire river orleans france abstract non invasive geophysical methods are often used for detecting near surface defects and monitoring seepage in river dykes or dams between 2008 and 2009 a series of geophysical experiments was conducted to detect karst features below the dykes of the loire river orleans france multi channel analysis of seismic surface waves masw was used to obtain the shear wave velocity vs profile of the subsurface below the dykes as an effective approach to investigating the structure of the dykes multi channel resistivity surveys were also used to evaluate the electrical properties of material inside and under the dykes this study discusses the exploration strategy and results for several sections of the dyke system based on the experimental data vs contours are used to geometrically and qualitatively describe the subsurface under the dykes and identify areas of mechanical weakness corresponding to karst features while resistivity contours allow distinguishing interactions between the karst and the dykes through the identification of areas of downward material movement known and unknown anomalies are identified a practical approach that combines seismic and electric resistivity results is proposed to assess karst presence and sinkhole hazards along the investigated dykes using a susceptibility index referring to the likelihood level of the events as a validation method areas of strong karst susceptibility index along the dykes are compared to known collapse event sinkholes dyke breaches etc locations available in databases

vertical coherence of ambient noise in shallow water overlying a fluid seabed broadband 200 hz 20 khz measurements of the vertical coherence of ambient noise in two well surveyed shallow water channels with fluid sedimentary seabeds are reported the noise at one of the sites the strataform natural laboratory off eureka northern california was occasionally found to be exclusively wind generated with negligible contributions from surface traffic and biological sources under these conditions the theoretical coherence computed using the known properties of the sediment at eureka closely follows the coherence data up to a frequency of 20 khz subtle effects due to the finite depth of the sources that is the bubbles produced by wave breaking are evident in both the theory and the data at the second site in jellicoe channel new zealand some 64 km north of auckland wind noise again was a major factor but much of the time local shipping also contributed to the overall noise field two sets of coherence data from the new zealand site are examined the first taken in nea

matched field processing geoacoustic inversion and source signature recovery of blue whale vocalizations matched field processing mfp and global inversion techniques have been applied to vocalizations from four whales recorded on a 48 element tilted vertical array off the channel islands in 1996 global inversions from selected whale calls using as few as eight elements extracted information about the surrounding ocean bottom composition array shape and the animal s position these inversion results were then used to conduct straightforward mfp on other calls the sediment sound speed inversion estimates are consistent with those derived from sediment samples collected in the area in general most animals swam from the east to west but one animal remained within 500 m of its original position over 45 min all whales vocalized between 10 and 40 m depth three acoustic sequences are discussed in detail the first illustrating a match between an acoustic track and visual sighting the second tracking two whales to ranges out to 8 km and the final sequence demonstrating high resolution dive profiles from

the principal components statistical method as a complementary approach to geochemical methods in water quality factor identification application to the coastal plain aquifer of israel abstract in general schoeller and piper diagrams as well as other classical techniques facilitate the description of the various geochemical groups of water and help to explain quality changes in an aquifer we propose the use mainly of principal components analysis for identification of relevant groups of water and the factors that bring about a change in their quality the major advantage of this method is its suitability for simultaneous analysis of a great number of variables and observations it is here being applied for the investigation of the dan metropolitan region of israel s coastal plain the variables involved include major ions as well as the physical factors of depth of the well intake filter below sea level distance from the sea and aquifer recharge the primary purpose of this work is to demonstrate the use and reliability of principal components analysis pca as a method complementary to classical approaches for hydrogeochemical research subsidiary purposes involve determination of the major water groups characterizing the coastal plain aquifer identification of some of the principal variables that influence changes in water quality in the aquifer and description of some of the geochemical phenomena contributing to change in aquifer water quality the following results were achieved for the test area 1 1 two major groups of water were identified a low salinity calcium bicarbonate water occurring in the phreatic portion of the coastal plain aquifer and a more saline sodium chloride water characterizing the neighboring cenomanian aquifer and the confined portions of the coastal plain aquifer 2 2 the major water input sources such as rain injection water waste water irrigation etc may vary in their influence upon resulting water quality this water quality is affected by such physical factors as distance from the sea depth of well intake filters below sea level proximity to streams and the lithology of the saturated and unsaturated zones 3 3 the evolutionary alteration in content of specific ions with time can be clearly visualized on the same graph by means of pca the universal applicability of such a statistical approach to other hydrological settings is noted

geoacoustic inversion of ship radiated noise in shallow water using data from a single hydrophone the centre for maritime research and experimentation conducted a geoacoustic inverse experiment in the mediterranean sea in the summer of 2012 among the objectives was to employ an autono mous underwater vehicle to collect acoustic data to invert for properties of the seafloor inversion results for the compression wave speed in the bottom and the source spectrum of the r v alliance during a close approach to the bottom moored vehicle are presented the estimated wave speed was 1529m s r 10 the source spectrum of the alliance was estimated across more than six octaves of frequency

tomographic inversion of geoacoustic properties in a range dependent shallow water environment this paper presents a matched field tomographic method to estimate the geoacoustic properties of the ocean bottom for a range dependent medium in shallow water the inversion method has been developed in order to interpret experimental data from the haro strait primer sea trial this experiment was carried out in june 96 and used low frequency broadband signals that were received on three vertical line arrays inversion of the data is particularly difficult because of the complex bathymetry of the haro strait experimental site for this inversion a range dependent ray code was developed to solve the forward problem allowing an arbitrarily layered bottom environment the inversion scheme is based on modeling the propagation time and the amplitude of the recorded data and a simple new cost function is proposed the signal ray paths are identified automatically using a simple process that compares calculated and measured travel times data from multiple source positions are used to invert the range dependence of the geoacoustic model the environment is separated into segments and within each segment the inversion is carried out layer by layer for a multilayer geoacoustic model starting with the topmost layer the range dependent thickness and sound speed are estimated via a monte carlo method inversion results are presented for synthetic and experimental data from the haro strait sea trial

conodont biostratigraphy of the mid carboniferous boundary in western ireland two stratigraphic sections spanning the mid carboniferous boundary were examined in the clare shale formation of the shannon basin in western ireland calcareous nodules intermittently occur within these generally non calcareous organic rich shales and these have yielded serpukhovian and bashkirian conodont elements the biostratigraphic range of the irish material is illustrated here for the first time results show that the mid carboniferous and arnsbergian chokierian boundaries are coincident at ballybunion gnathodus girtyi is restricted to the lower part of the serpukhovian stage late mississippian while g bilineatus bollandensis persists into much younger strata close to the first occurrence of declinognathodus noduliferus s l one element belonging to g postbilineatus is also present these findings support the argument that d noduliferus s l developed from g b bollandensis rather than from g girtyi the biostratigraphical tool for the identification of the mid carboniferous boundary globally and the suitability of the section at arrow canyon usa as a gssp may therefore need to be reassessed

the impact of ocean sound speed variability on the uncertainty of geoacoustic parameter estimates this paper investigates the influence of water column variability on the estimates of geoacoustic model parameters obtained from matched field inversions the acoustic data were collected on the new jersey continental shelf during shallow water experiments in august 2006 the oceanographic variability was evident when the data were recorded to quantify the uncertainties of the geoacoustic parameter estimates in this environment bayesian matched field geoacoustic inversion was applied to multi tonal continuous wave data the spatially and temporally varying water column sound speed is parametrized in terms of empirical orthogonal functions and included in the inversion its impact on the geometric and geoacoustic parameter estimates is then analyzed by the inter parameter correlations two different approaches were used to obtain information about the variation of the water sound speed one used only the profiles collected along the experimental track during the experiment and the other also included observations collected over a larger area the geoacoustic estimates from both the large and small sample sets are consistent however due to the diversity of the oceanic sound speed more empirical orthogonal functions are needed in the inversion when more sound speed profile samples are used

internal characterization of embankment dams using ground penetrating radar gpr and thermographic analysis a case study of the medau zirimilis dam sardinia italy abstract the stability of embankment dams without an impermeable core depends on the characteristics of the face slab that prevents internal erosion piping and eventual collapse of the structure under a mediterranean climate the impermeable asphaltic face slab is subjected to high solar radiation and consequent temperature changes which can generate the creation of cracks and joints the medau zirimilis dam located in the casteddu river sardinia is an embankment dam that has undergone seepage and continuous repairs in its asphalt face slab these reparations have been conducted because of the occurrence of cracks and relative movement of different segments of the slab to evaluate if seepage endangers the integrity of the dam gpr was used with different antennas 100 250 and 500 mhz along its crest and upstream and downstream faces and the data were integrated with infrared thermographic images although geophysical data do not show structural changes affecting the main dam structure deformation structures at shallow levels and in particular in the upstream face and along the crest of the dam have been identified such deformation affects the road atop the crest the face slab and underlying levels resulting in landslides that include material from several meters below the surface the analysis permitted the identification of the origin of surficial cracks and their effects on the face slab these sectors independent of current movement define the most unstable areas against water level changes that can affect the dam integrity gpr analysis at the embankments usually has the handicap of high clay content that precludes electromagnetic wave penetration however in this case the obtained resolution and extent of penetration using the different antennas was sufficient due to the absence of an inner waterproof unit and permitted the evaluation of the inner structure of the dam and the application of gpr for construction quality surveillance internal structural characterization and dam monitoring

geoacoustic inversion in time domain using ship of opportunity noise recorded on a horizontal towed array a time domain geoacoustic inversion method using ship noise received on a towed horizontal array is presented the received signal containing ship noise as a source of opportunity is time reversed and then back propagated to the vicinity of the ship the back propagated signal is correlated with the modeled signal which is expected to peak at the ship s location in case of a good match for the environment this match is utilized for the geoacoustic parameter inversion the objective function for this optimization problem is thus defined as the normalized power focused in an area around the source position using a matched impulse response filter a hybrid use of global and local search algorithms i e ga and powell s method is applied to the optimization problem applications of the proposed inversion method to mapex 2000 noise experiment conducted north of the island of elba show promising results and it is shown that the time domain inversion takes advantage of dominant frequencies of the source si

factors responsible for high arsenic concentrations in two groundwater catchments in taiwan abstract high as contents in groundwater were found in two neighboring catchments the chianan plain and the southern choushui river alluvial fan in taiwan the groundwater quality the redox potential and the as distribution of the chianan plain were characterized using factor analysis redox zoning and a geochemical program the results were compared with those of the southern choushui river alluvial fan possible as release mechanisms are also elucidated factors 1 and 2 of the groundwater in the chianan plain the salinization factor and the as enrichment factor are similar to those in the southern choushui river alluvial fan however the spatial distribution of reductive tendency in the chianan plain is different to that in the choushui river alluvial fan and yields spatially distinct hydrogeochemical environments in these two neighboring areas the reduction potential in the chianan plain is stronger than that in the choushui river alluvial fan the difference between the reduction potentials in these two vicinal areas influences the concentrations of as in groundwater the reductive dissolution of as rich fe oxyhydroxide is suggested to be the major mechanism for release of as to the groundwater in the chianan plain and the choushui river alluvial fan of taiwan

groundwater evolution in the continental intercalaire aquifer of southern algeria and tunisia trace element and isotopic indicators abstract the geochemical processes taking place along an 800 km flow line in the non carbonate continental intercalaire aquifer ci aquifer in north africa are described using chemical major and trace element and isotopic indicators the aquifer is hydraulically continuous from the atlas mountains in algeria to the chotts of tunisia and the geochemical evidence corroborates this the highest discharge temperature is 73 c but silica geothermometry indicates a maximum temperature of 94 c at depth chloride concentrations increase from 200 to 800 mg l 1 and the br cl ratios confirm the dissolution of non marine evaporites or interstitial waters as the main source of salinity fluoride concentrations are low and are likely to be derived from rainfall recording oscillations in source radiocarbon ages except near outcrop are at or near detection limits and the 18o and 2h values indicate a cooler recharge regime with rainfall having lower primary evaporation than today this is shown by the fact that mean isotope ratios of ci waters are around 3 lighter than the present day weighted mean value for rain major ion ratios and most trace elements indicate that despite the complex structure and stratigraphy uniform evolution with continuous water rock interaction takes place along the flow lines which are only disturbed near the tunisian chotts by groundwater converging from additional flow lines the ageing of the water can also be followed by the smooth increase in several indicator elements such as li k and mn which are least affected by solubility controls similarly the influence of marine facies in the tunisian sector may be recognised by the changing mg ca and higher br cl as well as trace element indicators the groundwaters are oxidising up to 300 km from outcrop dissolved o2 has persisted for at least 20 ka and within this zone the concentrations of several elements forming oxy anions such as u and cr increase and no3 remains conservative beyond 300 km from outcrop the groundwaters are reducing and contain high fe concentrations the basin contains huge reserves of fresh brackish waters but these need careful development due to the limiting high salinity and scaling tendency resulting from the high temperatures and mineral super saturation caused during abstraction as well as high concentrations of some harmful elements such as cr in the oxidising section

range dependent geoacoustic inversion of vertical line array data using matched beam processing this paper describes the results of range dependent geoacoustic inversion using vertical line array data obtained from the 4th matched acoustic properties and localization experiment conducted in the east sea of korea the narrowband multitone continuous wave signal from the towed source was analyzed to estimate the range dependent geoacoustic properties along the radial track the primary approach is based on the sectorwise inversion scheme the inversion region up to 7 5 km from the vertical line array was divided into several segments and the subinversions for each segment were performed sequentially to reduce the dominance of low angle arrivals which bears little information for the bottom segment in question matched beam processing with beam filtering was used for the cost function the performance of proposed algorithm was tested using simulated data for an environment representative of the experimental site the inversion results for the experimental data were consistent with the geophysical database and were validated from matched field source localization using frequencies different from those used in the inversion

three dimensional geological modelling and multivariate statistical analysis of water chemistry data to analyse and visualise aquifer structure and groundwater composition in the wairau plain marlborough district new zealand summary concerns regarding groundwater contamination with nitrate and the long term sustainability of groundwater resources have prompted the development of a multi layered three dimensional 3d geological model to characterise the aquifer geometry of the wairau plain marlborough district new zealand the 3d geological model which consists of eight litho stratigraphic units has been subsequently used to synthesise hydrogeological and hydrogeochemical data for different aquifers in an approach that aims to demonstrate how integration of water chemistry data within the physical framework of a 3d geological model can help to better understand and conceptualise groundwater systems in complex geological settings multivariate statistical techniques e g principal component analysis and hierarchical cluster analysis were applied to groundwater chemistry data to identify hydrochemical facies which are characteristic of distinct evolutionary pathways and a common hydrologic history of groundwaters principal component analysis on hydrochemical data demonstrated that natural water rock interactions redox potential and human agricultural impact are the key controls of groundwater quality in the wairau plain hierarchical cluster analysis revealed distinct hydrochemical water quality groups in the wairau plain groundwater system visualisation of the results of the multivariate statistical analyses and distribution of groundwater nitrate concentrations in the context of aquifer lithology highlighted the link between groundwater chemistry and the lithology of host aquifers the methodology followed in this study can be applied in a variety of hydrogeological settings to synthesise geological hydrogeological and hydrochemical data and present them in a format readily understood by a wide range of stakeholders this enables a more efficient communication of the results of scientific studies to the wider community

assessment of the impact of anthropogenic activities on the groundwater hydrology and chemistry in tarsus coastal plain mersin se turkey using fuzzy clustering multivariate statistics and gis techniques summary tarsus coastal plain tcp is an economically and ecologically important area situated in between the fertile fluvio deltaic plains of two rivers delicay and tarsus mersin se turkey where anthropogenic activities agricultural industrial and domestic are very intense twenty four water quality parameters were surveyed at 193 groundwater and 10 surface water sites during august 2008 the objective was to characterize the physico chemical properties of groundwaters in tcp assess the impact of anthropogenic activities on the groundwater hydrology and chemistry and identify the major hydrogeochemical processes occurring in the area groundwater samples were grouped into hydrochemically distinct and spatially continuous four water classes i e c1 c2 c3 and c4 using the fuzzy c means fcm clustering method where membership values were interpolated using the ordinary kriging technique principal components analysis pca was used to decipher various underlying natural and anthropogenic processes creating these distinct water classes four principal components pcs were extracted in pca which explained more than 73 of the total variance in water quality major factors responsible for the variations in chemistries of water classes are identified as 1 water rock interaction and nitrate contamination 2 salinization by seawater intrusion and evaporite dissolution 3 geogenic anthropogenic cr fe and mn and 4 anthropogenic zn pollution overexploitation of the aquifer is clearly evident especially at settlements located near the coastal zone where the water table is lowered 2 5 m below the sea level salinization is well known in the area and is attributed not only to seawater intrusion but also to dissolution of evaporitic series from the handere formation hydrochemical evidence also suggest that in the area subsurface paleo river channels and the deposits infilling the ancient lagoon area within quaternary recent alluvial deposits act as significant hydrological features where preferential groundwater flow occurs along them

factor analysis in hydrogeochemistry of coastal aquifers a preliminary study this paper examines the results of r mode factor analysis performed on major ion data from a hydrogeochemical survey over the coastal quaternary deltaic aquifer of the cauvery basin tamil nadu india seven major ions ca mg na k hco3 cl and no3 were analyzed from each of the 126 water samples collected in two seasons pre and post monsoon 63 each a set of factors was found both in pre monsoon and post monsoon data which explained the source of the dissolved ions and the chemical processes which accompany the intrusion of seawater

bayesian geoacoustic inversion of ship noise on a horizontal array this paper applies geoacoustic inversion to low frequency narrow band acoustic data from a quiet surface ship recorded on a bottom moored horizontal line array in shallow water a bayesian matched field inversion method is employed which quantifies geoacoustic uncertainties and allows for meaningful comparison of inversion results from different data sets geoacoustic inversion results for ship noise data are compared with inversion results for multitone data from a towed controlled source collected in the same experiment and with independent geophysical measurements to increase the information content of low level ship noise data the effect of including multiple independent data segments in the inversion is investigated and shown to significantly reduce geoacoustic parameter uncertainties geoacoustic uncertainties are also shown to depend on ship range and orientation with increased uncertainties for long ranges and for the ship stern oriented away from the array

geoacoustic inversion of ambient noise a simple method the vertical directionality of ambient noise is strongly influenced by seabed reflections therefore potentially geoacoustic parameters can be inferred by inversion of the noise in this approach using vertical array measurements the reflection loss is found directly by comparing the upward with the downward going noise theory suggests that this simple ratio is in fact the power reflection coefficient potentially a function of angle and frequency modeling and parameter searching are minimized and the method does not require a detailed knowledge of the noise source distribution the approach can handle stratified environments and is believed to tolerate range dependence experimental data from five sites four in the mediterranean one on the new jersey shelf are described most of the mediterranean sites had temporally varying noise directionality yet yielded the same reflection properties as one would hope one site was visited in conditions of very low surface noise this paper concentrates on an experimental demonstration of the feasibility of the method and data quality issues rather than automatic search techniques for geoacoustic parameters

inversion for range dependent water column sound speed profiles on the new jersey shelf using a linearized perturbative method the environment of the new jersey shelf is characterized by high spatial and temporal variability of water column properties caused by intrusions of warm salty water from the continental slope these intrusions cause fluctuations in the water column sound speed profile which can have significant effects on acoustic propagation in shallow water in this work a linearized perturbative inverse technique is applied to estimate range dependent water column sound speed profiles this method utilizes estimates of horizontal wave numbers to determine sound speed as a function of depth this technique is appropriate for the range dependent shallow water environment as horizontal wave numbers can be measured semilocally 1 2 km aperture and their values are a direct measurement of the local environmental parameters difficulty is encountered in application of the perturbative inverse technique because the wave number data are insensitive to some portions of the waveguide and as a result the solution can deviat

identifying key parameters to differentiate groundwater flow systems using multifactorial analysis summary multivariate techniques are useful in hydrogeological studies to reduce the complexity of large scale data sets and provide more understandable insight into the system hydrology in this study principal component analysis pca has been used as an exploratory method to identify the key parameters that define distinct flow systems in the selva basin ne spain in this statistical analysis all the information obtained in hydrogeological studies that is hydrochemical and isotopic data but also potentiometric data is used additionally cluster analysis based on pca results allows the associations between samples to be identified and thus corroborates the occurrence of different groundwater fluxes pca and cluster analysis reveal that two main groundwater flow systems exist in the selva basin each with distinct hydrochemical isotopic and potentiometric features regional groundwater fluxes are associated with high f contents and confined aquifer layers while local fluxes are linked to nitrate polluted unconfined aquifers with a different recharge rates in agreement with previous hydrogeological studies these statistical methods stand as valid screening tools to highlight the fingerprint variables that can be used as indicators to facilitate further more arduous analytical approaches and a feasible interpretation of the whole data set

bayesian geoacoustic inversion using wind driven ambient noise this paper applies bayesian inversion to bottom loss data derived from wind driven ambient noise measurements from a vertical line array to quantify the information content constraining seabed geoacoustic parameters the inversion utilizes a previously proposed ray based representation of the ambient noise field as a forward model for fast computations of bottom loss data for a layered seabed this model considers the effect of the array s finite aperture in the estimation of bottom loss and is extended to include the wind speed as the driving mechanism for the ambient noise field the strength of this field relative to other unwanted noise mechanisms defines a signal to noise ratio which is included in the inversion as a frequency dependent parameter the wind speed is found to have a strong impact on the resolution of seabed geoacoustic parameters as quantified by marginal probability distributions from bayesian inversion of simulated data the inversion method is also applied to experimental data coll

hydrochemical characteristics of aquifers near sutherland in the western karoo south africa the western karoo depends entirely on groundwater for domestic and agricultural use an understanding of the chemical evolution of the groundwater provides insight into the interaction of water with the environment and contributes to better resource management descriptive statistics correlation matrices and factor analysis together with stable isotope data were used to gain an understanding of the hydrochemical processes of the groundwaters in the fractured rocks around sutherland in the western karoo the main processes influencing the groundwater chemistry are salinisation mineral precipitation and dissolution cation exchange and human activity the stable isotope data indicate that the infiltration of evaporated water is partly responsible for the occurrence of saline subsurface waters the ionic oxygen and hydrogen stable isotope composition of the groundwaters suggests that the effects of localised topography are one of the overriding factors controlling the groundwater chemistry in higher lying areas ca hco3 2 type waters are prevalent while in topographical flat areas nacl type waters dominate in areas where water collects close to or at the surface saline soils are formed from these areas salts are leached to the subsurface during significant recharge periods these findings are important in that they contribute to the identification of suitable locations for developing groundwater resources that could yield a relatively better quality water q 2001 elsevier science b v all rights reserved

detection and characterization of animal burrows within river embankments by means of coupled remote sensing and geophysical techniques lessons from river panaro northern italy abstract the damage and the eventual breach of river embankments may be due to internal erosion and instability processes in the waterside and landside slopes beside the progressive degradation of soil properties different types of macro pores inside the levee body can influence its short and long term performance among macro pores burrows are a widespread form of biologic erosion of earthen structures potentially producing damage or even their collapse in fact animal burrows are erosion tunnels which can lead to piping phenomena thus the emergent risk connected to burrowing animals in earthen levees has to be tackled given also the environmental changes driven by human activity and climate remote sensing and geophysical surveys can complement data from in situ investigation campaigns in the definition of the real embankment model as well as in the imaging of local defects which may influence its local and or global stability several techniques were integrated in the study area of the panaro river where an active animal burrow was detected in spring 2015 two campaigns were carried out survey 1 in june 2015 just after the relocation of the animals and survey 2 in december 2015 after the filling of the burrow with a cement bentonite slurry here we highlight the peculiarity of each method and the choice of an integrated multi technique approach the results allowed the known burrow as well as two other tunnels to be imaged in 3d providing specific guidelines for the best integrated strategy to detect and characterize these macro pores in a fluvial levee the proposed approach can advance our knowledge of embankments in space and time so that effective remedial actions in flood risk and wildlife management can be identified

red bed and basement sourced fluids recorded in hydrothermal mn fe as veins sailauf germany a la icpms fluid inclusion study the hydrothermal mn fe as vein mineralization at sailauf germany hosts a complex sequence of oxide and carbonate minerals that record a protracted fluid history the mineralization is related to a major unconformity that separates permian zechstein sedimentary rocks from underlying variscan crystalline basement the hydrothermal veins contain two principal mineralization stages which are mn oxides associated with calcite and hematite associated with mn calcite the fluid evolution of the hydrothermal system has been reconstructed from fluid inclusion petrography microthermometry and la icpms microanalysis coupled with stable isotope geochemistry of carbonate and oxide minerals the fluid inclusions are high salinity sodic calcic brines and the bulk fluid properties show no major differences between the mn oxide and the hematite stage la icpms analysis of major and trace elements demonstrates that the mineralization formed from chemically distinct fluid pulses characterized by variations in their k li b pb and zn concentrations the fluid that precipitated the mn oxide stage has anomalous pb zn and li b ratios which closely resemble fluids found in fracture fillings in red beds of the permian rotliegend basin by contrast the fluids associated with the hematite stage have pb zn and li b ratios typical of crustal fluids that were derived from interaction with crystalline basement both fluids possess characteristic element ratios including cl br but variable absolute concentrations of most metals this suggests that both fluids were modified by mixing with a common metal depleted brine that had a similar cl br ratio most likely a formation water from the overlying zechstein sedimentary rocks the sailauf mineralization provides insight into the protracted post variscan fluid evolution at the basement cover interface the compositionally anomalous fluid that precipitated the mn oxides is comparable to brines derived from interaction with red beds and likely represents the ore fluid of kupferschiefer type sediment hosted cu deposits conversely the fluid that deposited the hematite mineralization resembles fluids that typically form basement and sediment hosted pb zn deposits

compositional multivariate statistical analysis of thermal groundwater provenance a hydrogeochemical case study from ireland abstract thermal groundwater is currently being exploited for district scale heating in many locations world wide the chemical compositions of these thermal waters reflect the provenance and circulation patterns of the groundwater which are controlled by recharge rock type and geological structure exploring the provenance of these waters using multivariate statistical analysis msa techniques increases our understanding of the hydrothermal circulation systems and provides a reliable tool for assessing these resources hydrochemical data from thermal springs situated in the carboniferous dublin basin in east central ireland were explored using msa including hierarchical cluster analysis hca and principal component analysis pca to investigate the source aquifers of the thermal groundwaters to take into account the compositional nature of the hydrochemical data compositional data analysis coda techniques were used to process the data prior to the msa the results of the msa were examined alongside detailed time lapse temperature measurements from several of the springs and indicate the influence of three important hydrogeological processes on the hydrochemistry of the thermal waters 1 salinity and increased water rock interaction 2 dissolution of carbonates and 3 dissolution of sulfides sulfates and oxides associated with mineral deposits the use of msa within the coda framework identified subtle temporal variations in the hydrochemistry of the thermal springs which could not be identified with more traditional graphing methods or with a standard statistical approach the msa was successful in distinguishing different geological settings and different annual behaviours within the group of springs this study demonstrates the usefulness of the application of msa within the coda framework in order to better understand the underlying controlling processes governing the hydrochemistry of a group of thermal springs in a low enthalpy setting

hydrogeochemical analysis of multiple aquifers in a coal mine based on nonlinear pca and gis hydrogeochemical characteristic analysis of multiple categorical aquifers including the delineation of hydrogeochemical spatial distributions can provide a basic understanding of the groundwater flow system necessary for the prevention and control of groundwater damage associated with coal mines nonlinear principal component analysis pca was used to analyse the groundwater chemical characteristics of water samples from five aquifers in gubei coal mine anhui province china in particular ca2 mg2 na k hco3 cl so4 2 and ph were analysed to analyse the spatial distribution of groundwater chemistry in this permian fractured aquifer interpolation of principal component 1 pc1 scores obtained from the nonlinear pca was performed using the inverse distance weighting idw method additionally concentrations of the hydrogeochemical variables were plotted against depth the relationships between water samples variables and water samples with variables were simultaneously analysed by nonlinear pca the results show 1 nonlinear pca explains more variability than standard pca in the first two principal components pcs 2 the cenozoic top aquifer has low concentrations of na k and cl the cenozoic middle aquifer and cenozoic bottom aquifer are characterised by high concentrations of ca2 and mg2 and low concentrations of hco3 the shallow groundwater of the permian fractured aquifer is recharged by the cenozoic bottom aquifer while other parts have high concentrations of hco3 and low concentrations of ca2 and mg2 the taiyuan limestone aquifer has similar groundwater chemistry to that of the cenozoic bottom aquifer and thus it may be recharged by the cenozoic bottom aquifer in outcropping taiyuan formation strata 3 the wide south western and north western areas of the permian fractured aquifer may be recharged by the cenozoic bottom aquifer and 4 concentrations of ca2 and mg2 in the permian fractured aquifer are negatively correlated with sampling depth while the concentrations of na k and hco3 are positively correlated with sampling depth which verifies that the shallow groundwater of this permian fractured aquifer is recharged by the cenozoic bottom aquifer the findings demonstrate that combining nonlinear pca with gis can be a powerful approach for conducting spatial nonlinear analysis of hydrogeochemical characteristics

parameter estimation using multifrequency range dependent acoustic data in shallow water the estimation of all forward model parameters geometric geoacoustic and ocean sound speed by the inversion of acoustic field observations is considered the data was taken at a mildly range dependent shallow water site in the mediterranean sea the inversion is based on data from a vertical array and carried out using information at multiple frequencies global optimization using a directed monte carlo search based on genetic algorithms and the bartlett objective function is used all geometric parameters are well determined a range dependent geoacoustic model is determined and the ocean sound speed is estimated comparisons of the observed pressure field as a function of depth and the predicted field show good agreement the use of observations at multiple frequencies provides considerable stability for the estimated parameters optimization of only geometric and geoacoustic parameters in a range independent environment is found to be satisfactory at the lower frequencies 165 175 hz but for the h

source localization in a time varying ocean waveguide one of the most stringent impairments in matched field processing is the impact of missing or erroneous environmental information on the final source location estimate this problem is known in the literature as model mismatch and is strongly frequency dependent another unavoidable factor that contributes to model mismatch is the natural time and spatial variability of the ocean waveguide as a consequence most of the experimental results obtained to date focus on short source receiver ranges usually 5 km stationary sources reduced time windows and frequencies generally below 600 hz this paper shows that mfp source localization can be made robust to time space environmental mismatch if the parameters responsible for the mismatch are clearly identified properly modeled and time adaptively estimated by a focalization procedure prior to mfp source localization the data acquired during the advent 99 sea trial at 2 5 and 10 km source receiver ranges and in two frequency bands below and above 600 hz provided an excellent opportunity to test the proposed techniques the results indicate that an adequate parametrization of the waveguide is effective up to 10 km range in both frequency bands achieving a precise localization during the whole recording of the 5 km track and most of the 10 km track it is shown that the increasing mfp dependence on erroneous environmental information in the higher frequency and at longer ranges can only be accounted for by including a time dependent modeling of the water column sound speed profile

inversion for sediment geoacoustic properties at the new england bight this article discusses inversions for bottom geoacoustic properties using broadband acoustic signals obtained from explosive sources two different inversion schemes for estimating the compressional wave speeds and attenuation are presented in this paper in addition to these sediment parameters source receiver range is also estimated using the arrival time data the experimental data used for the inversions are sus charge explosions acquired on a vertical hydrophone array during the shelf break primer experiment conducted south of new england in the middle atlantic bight in august 1996 the modal arrival times are extracted using a wavelet analysis in the first inversion scheme arrival times corresponding to various modes and frequencies from 10 to 200 hz are used for the inversion of compressional wave speeds a hybrid inversion scheme based on a genetic algorithm ga is used for the inversion in an earlier study potty et al j acoust soc am 108 3 973 986 2000 have used this hybrid scheme in a range independent environment in the present study results of range dependent inversions are presented the sound speeds in the water column and bathymetry are assumed range dependent whereas the sediment compressional wave speeds are assumed range independent the variations in the sound speeds in the water column are represented using empirical orthogonal functions eofs the replica fields corresponding to the unknown parameters were constructed using adiabatic theory in the second inversion scheme modal attenuation coefficients are calculated using modal amplitude ratios the ratios of the modal amplitudes are also calculated using time frequency diagrams a ga based inversion scheme is used for this search finally as a cross check the computed compressional wave speeds along with the modal arrival times were used to estimate the source receiver range the inverted sediment properties and ranges are seen to compare well with in situ measurements and historical data

monitoring and characterizing the deformation of an earth dam in guangxi province china abstract failures and severe deformation of earth dams have been reported frequently in the past decades extensive studies have been performed to monitor dam displacements to develop dam remediation plans however the long term monitoring of dam displacements and the effects of remediation on dam deformation are rarely studied in this study the vertical and lateral displacements of an earth dam in guangxi province southwestern china were monitored over an 18 year period the piezometric pressure was measured for the analysis of triggered seepage furthermore acoustic testing and borehole television tests were performed to examine the integrity of the cutoff wall that was built to prevent dam leakage and excessive deformation the results show that the largest lateral displacement of 65 8 mm and the maximum settlement of 178 mm are both located at the center of the dam and that the lateral displacement and settlement decrease gradually from the center to both abutments moreover greater settlements were observed on the side of the dam upstream of the cutoff wall the lateral displacements are dominated by the hydraulic pressure of the impounded water the dam settlements are generally determined by the thickness of the compacted soil along the longitudinal section the analysis shows that the greater settlements on the upstream side of the dam are attributed to dynamic seepage induced by the water level changes in the reservoir indicating that the cutoff wall effectively alleviated the seepage effects on the downstream side of the dam thus the dam s upstream face should be remediated to minimize the dynamic water level effects

the effects of environmental variability and spatial sampling on the three dimensional inversion problem the overall goal of this work is to quantify the effects of environmental variability and spatial sampling on the accuracy and uncertainty of estimates of the three dimensional ocean sound speed field in this work ocean sound speed estimates are obtained with acoustic data measured by a sparse autonomous observing system using a perturbative inversion scheme rajan lynch and frisk j acoust soc am 82 998 1017 1987 the vertical and horizontal resolution of the solution depends on the bandwidth of acoustic data and on the quantity of sources and receivers respectively thus for a simple range independent ocean sound speed profile a single source receiver pair is sufficient to estimate the water column sound speed field on the other hand an environment with significant variability may not be fully characterized by a large number of sources and receivers resulting in uncertainty in the solution this work explores the interrelated effects of environmental variability and spatial sampling o

water rock interaction processes in the triassic sandstone and the granitic basement of the rhine graben geochemical investigation of a geothermal reservoir saline fluids have been collected in the rhine graben over the last two decades both from the triassic sandstone aquifer and the granitic basement down to a depth of 3500m their salinities and location are compared in order to distinguish the respective influences of temperature and host rock mineralogy in the water rock interaction processes the comparison shows that sulphates in the sedimentary formations were dissolved by the fluids which also led to br enrichment mica dissolution has strongly increased the rb and cs contents which then provide an indication of the degree of water rock interaction the sr isotopic ratios are used to compare the fluids with the granite minerals two relationships are revealed for the fluids in the sandstone and the granite one related to widespread mica dissolution which could have affected both the buntsandstein and the granite and the other to subsequent plagioclase dissolution which is observed only in the granite computations showed that 12 5g of mica and 1 658 of plagioclase per liter of fluid have been dissolved the nature of these two relationships suggests two different evolutions for the fluids and the individualization of the two reservoirs during the graben s history the cation concentrations are mainly controlled by temperature and are independent of the type of host rock equilibrium with the rock mainly caused ca and k concentration variations which has induced clear ca k and ca 18o k 18o correlations geothermometric computations indicate that with increasing depth the cations the silica and the 18o so4 geothermometers evolve towards a value close to 230 c this demonstrates the existence of a hot reservoir in the granite of the graben at a depth estimated at 4 5 5 km

effect of ocean sound speed uncertainty on matched field geoacoustic inversion the effect of ocean sound speed uncertainty on matched field geoacoustic inversion is investigated using data from the sw06 experiment along a nearly range independent bathymetric track significant sound speed differences were observed at the source and receiving array and several environmental parameterizations were investigated for the inversion including representing the ocean sound speed at both source and receivers with empirical orthogonal function eof coefficients a genetic algorithm based global optimization method was applied to the candidate environmental models then a bayesian inversion technique was used to quantify uncertainty in the environmental parameters for the best environmental model which included an eof description of the ocean sound speed

estimates of the temporal and spatial variability of ocean sound speed on the new jersey shelf estimates of the spatial and temporal variability of ocean sound speed on the new jersey shelf were obtained using acoustic signals measured by a set of freely drifting buoys the range and time dependent inversion problem is computationally intensive and a linearized perturbative algorithm was applied to obtain results in an efficient manner the inversion algorithm uses estimates of modal travel time to determine sound speed as a function of range and depth in order to handle the high volume of data associated with the acoustic sensing network the modal travel time estimation process was automated using an adaptive time frequency signal processing method known as time warping time warping is a model based transform that converts the frequency dependent modal arrivals to monotones in the warped domain where they can be easily filtered the data analyzed in this paper were collected on 16 march 2011 on the new jersey shelf when the ocean was relatively well mixed while the observed sound speed variations are small both spatial and temporal trends are observed in the results furthermore the estimated sound speed profiles show good agreement with temporally and spatially collocated measurements