environmental and morphologic controls on wave induced dune response abstract the pacific northwest of the united states exhibits complex spatial patterns of storm induced coastal foredune erosion using oceanographic and morphologic data from three field sites encompassing a range of subaqueous and subaerial coastal profile configurations a relationship is found between morphologic characteristics and dune volume changes during storm events producing high water levels the data suggest that dune erosion increases with increasing backshore beach slope and that under particular oceanographic forcing conditions wave driven processes can grow the lower portion of dunes on low sloping dissipative beaches these observations of environmental and morphologic controls on storm induced dune impacts are further explored using xbeach a state of the art numerical model capable of simulating interactions between hydrodynamics and morphology consistent with the field data model simulations indicate that wave driven dune growth may occur on low sloping beaches in cases where the dynamic still water level still water level plus wave setup is lower than the dune toe however these accretional processes are restricted to events where limited incident wave energy impacts the dune cases with steep backshore beach slopes or dynamic still water levels exceeding the dune toe instead typically result in dune erosion additionally the model simulations suggest that morphologic properties of the shelf nearshore and the dune itself influence storm induced dune volume change therefore morphologic features far from the dune face including shelf geometries shaped in part by the regional historical sediment budget may have important implications on the susceptibility of coastal foredunes systems to storm impacts

internal structure of an alpine rock glacier based on crosshole georadar traveltimes and amplitudes rapid melting of permafrost in many alpine areas has increased the probability of catastrophic rock slides in an attempt to provide critical structural information needed for the design and implementation of suitable mitigation procedures we have acquired low frequency 22 mhz cross hole radar data from within a fast moving rock glacier an important form of alpine permafrost since the ice rock and pockets of water and air found in the underground of high alpine areas have very different dielectric permittivities and electrical conductivities the radar method was well suited for investigating the structure and state of the rock glacier our interpretation of the radar velocities and attenuations was constrained by geomorphological observations borehole lithological logs and the results of a surface seismic survey the radar data revealed the existence of a discontinuous 7 11 m thick ice rich zone distinguished by high velocities 0 14 0 17 m ns and low attenuations 0 04 0 09 m 1 and a thin underlying ice free zone characterized by moderate velocities 0 11 0 12 m ns and low attenuations 0 04 0 09 m 1 beneath these two zones we observed a prominent band of high velocities 0 14 0 17 m ns and moderately high attenuations 0 10 0 20 m 1 associated with unconsolidated glacial sediments and numerous large air filled voids which in the past were probably filled with ice at greater depths the variably dry to water saturated sediments were represented by generally lower velocities 0 08 0 10 m ns and higher attenuations 0 16 0 24 m 1 the bedrock surface was represented by an abrupt 0 03 m ns velocity increase we speculate that the disappearance of ice both laterally and with depth occurred during the past one to two decades

on the use of combined geophysical methods to assess water content and water conductivity of near surface formations abstract we propose to deepen the interpretation of combined geophysical methods georadar seismic and electric to assess physical properties characterizing the near surface porous formations especially the influence of water velocity analysis of multioffset georadar data are used together with seismic methods to estimate lateral and vertical ground water fluctuations this enables us to identify transitions from non saturated to fully saturated porous layers with certainty furthermore the accurate knowledge of seismic velocities helps to estimate the porosity of the ground water formations finally we show how the radar technique may be useful in solving the problem of trade off between bulk resistivity which is deduced from electrical measurements and that of water ionic conductivity and water content these theoretical considerations are illustrated using various measurements conducted at the same test site our interpretation is compared with a few laboratory measurements on water and soil samples this study displays the impact of combined geophysical approaches for providing models of water and ionic transfers down to a depth of several metres

the extreme 2013 2014 winter storms hydrodynamic forcing and coastal response along the southwest coast of england the southwest coast of england was subjected to an unusually energetic sequence of atlantic storms during the 2013 2014 winter with the 8 week period from mid december to mid february representing the most energetic period since at least 1953 a regional analysis of the hydrodynamic forcing and morphological response of these storms along the sw coast of england highlighted the importance of both storm and site specific conditions the key factor that controls the atlantic storm wave conditions along the south coast of southwest england is the storm track energetic inshore wave conditions along this coast require a relatively southward storm track which enables offshore waves to propagate up the english channel relatively unimpeded the timing of the storm in relation to the tidal stage is also important and coastal impacts along the macro tidal southwest coast of england are maximised when the peak storm waves coincide with spring high tide the role of storm surge is limited and rarely exceeds 1 m the geomorphic storm response along the southwest coast of england displayed considerable spatial variability this is mainly attributed to the embayed nature of the coastline and the associated variability in coastal orientation on west facing beaches typical of the north coast the westerly atlantic storm waves approached the coastline shore parallel and the prevailing storm response was offshore sediment transport many of these north coast beaches experienced extensive beach and dune erosion and some of the beaches were completely stripped of sediment exposing a rocky shore platform on the south coast the westerly atlantic storm waves refract and diffract to become southerly inshore storm waves and for the southeast facing beaches this results in large incident wave angles and strong eastward littoral drift many south coast beaches exhibited rotation with the western part of the beaches eroding and the eastern part accreting 2015 the authors earth surface processes and landforms published by john wiley sons ltd

a pseudo thellier relative palaeointensity record and rock magnetic and geochemical parameters in relation to climate during the last 276 kyr in the azores region summary in the pseudo thellier method for relative palaeointensity determinations tauxe et al 1995 the slope of the nrm intensity left after af demagnetization versus arm intensity gained at the same peak field is used as a palaeointensity measure we tested this method on a marine core from the azores spanning the last 276 kyr we compared the pseudo thellier palaeointensity record with the conventional record obtained earlier by lehman et al 1996 who normalized nrm by sirm the two records show similar features intensity lows with deviating palaeomagnetic directions at 40 45 ka and at 180 190 ka the first interval is associated with the laschamps excursion while the 180 190 ka low represents the iceland basin excursion channell et al 1997 the pseudo thellier method in combination with a jackknife resampling scheme provides error estimates on the palaeointensity spectral analysis of the rock magnetic parameters and the palaeointensity estimates shows orbitally forced periods particularly 23 kyr for climatic precession this suggests that palaeointensity is still slightly contaminated by climate fuzzy c means cluster analysis of rock magnetic and geochemical parameters yields a seven cluster model of predominantly calcareous clusters and detrital clusters the clusters show a strong correlation with climate for example samples from detrital clusters predominantly appear during rapid warming although both the pseudo thellier palaeointensity m a and fuzzy clusters show climatic influences we have not been able to find an unambiguous connection between the clusters and m a

swash oscillations on a natural beach run up swash oscillations were measured on a gently sloping beach face for a variety of incident wave conditions run up energy spectra at wind wave frequencies show an 3 dependence and energy levels that are independent of incident wave height this suggests saturation in contrast run up energy at surf beat periods increase approximately linearly with increasing incident wave energy thus in the inner surf zone where wave breaking limits the energy at wind wave frequencies the principal manifestation of large incident wind waves is energetic surf beat

quantifying thresholds for significant dune erosion along the sefton coast northwest england abstract field and model hindcast data are used to establish a critical dune erosion threshold for the sefton coast nw england events are classified as causing significant erosion if they result in a a mean dune retreat along the entire study area of 2 m b a dune retreat of 5 m along a coastal segment 2 km in length and c an eroded area 20 000 m2 for the period 1996 to 2008 individual storms were characterised using hindcast results from a polcoms wam model and measured data from the liverpool bay coastal observatory results show that combined extreme surge levels 1 5 m and wave heights 4 m or tidal water levels above 9 0 m chart datum cd do not always result in significant dune erosion evidence suggests that erosion is more likely to occur when wave heights are 2 6 m peak water level is 10 2 m cd at liverpool and when consecutive tidal cycles provide 10 h or more of water levels above 9 4 m cd however lower water levels and wave heights and shorter events of sustained water levels can cause significant erosion in the summer while the return period for events giving rise to the most severe erosion in the winter is 50 years significant erosion in the summer can be caused by events with return periods

wave spray induced sand transport and deposition during a coastal storm magilligan point northern ireland observations during a coastal storm at magilligan point northern ireland reveal characteristic surficial deposits onshore produced by landward transport of sand within spray generated by strong winds and breaking waves conditions necessary for formation of such deposits include an adequate sediment supply strong onshore waves and winds onshore waves of short period and a low coastal scarp the process which may be locally important is unlikely to be of great significance in contemporary sediment budget considerations and indicative figures suggest net landward transport rates of about 0 5 m 3 metre of shoreline hour during optimal conditions its importance as a source of cliff top sediment over longer time m periods may be greater c 1999 elsevier science b v all rights reserved

shoreline change patterns in sandy coasts a case study in sw spain abstract coastal changes on sandy shorelines are continuous and occur at diverse spatial and temporal scales gaining knowledge on beach change processes increases our capability to manage risks especially shoreline erosion affecting the increasing population living in coastal areas processes and factors involved in medium and short term beach changes depend on the morphological and dynamic characteristics of the coast in this work the decadal behaviour of 58 sandy beaches along the 150 km long south atlantic coast of spain between the guadalquivir river mouth and the strait of gibraltar is analysed in order to investigate the relationships between shoreline change patterns and the diverse morphological and dynamic factors controlling beach evolution in the area for this purpose georectified aerial photographs spanning the period 1956 2008 were compared in a gis environment to calculate rates of shoreline change short term evolution of beach profiles was also analysed in selected areas of interest results show that the study area exhibits a great variety of shoreline evolution trends with erosion prevailing in the northern and central sectors and stability or even accretion in the southern sector in general sediment availability is the main factor determining coastal erodibility in the area largely conditioned by the reduction in fluvial sediment supply caused by river basin regulation nearshore bathymetry also has a great significance as it controls wave refraction diffraction patterns and wave energy concentration on certain zones human interventions on the coast also represent a major influence on beach erodibility in the study area severe detrimental effects are caused at certain points by shore normal engineering structures blocking longshore drift additionally extensive urban development in backbeach environments has a significant influence on the sediment budget at certain areas on the basis of these results a morphological and evolutionary classification of sandy beaches is proposed taking into account the way beach morphology influences erosion accretion processes rectilinear beaches and enclosed beaches typically show dynamic equilibrium or even accretion trends whereas reef supported beaches tend to be dominated by erosion headland bay beaches show complex evolution patterns greatly influenced by local conditions such as specific shoaling processes or local winds this classification is useful not only in forecasting general shoreline behaviour in the near future but also in selecting the most appropriate type of intervention when managing retreating coasts

daily morphological changes determined by high energy events on an embayed beach a qualitative model this paper examines the daily morphological responses of sununga beach an embayed beach located on the south eastern brazilian coast to storms in the south atlantic ocean the main mechanisms and timing of beach erosion and accretion the relationship between wave height and direction and beach volume changes are considered to establish a qualitative model for short term embayed beach morphological changes the methodology consisted of daily topographic surveys during the month of may in 2001 2002 and 2003 using an rtk gps real time kinematics global positioning system weather and wave model results were used to correlate hydrodynamics and beach morphology the results indicate that the morphodynamics of sununga beach are characterized by a process of beach rotation which occurred more or less clearly during all three surveys unlike what has been commonly described in the literature for longer time intervals and alternations of fair and stormy weather the beach rotation processes on sununga beach occurred under conditions of moderate to high wave energy change wave heights greater than 2 m an integrated evaluation of the behaviour of the meteorological aspects together with beach morphology enabled us to recognize that extra tropical cyclones were the most important agent in remobilizing the beach planform whether in beach rotation or in cross shore erosion copyright 2010 john wiley sons ltd

dynamics of the douro estuary sand spit before and after breakwater construction abstract the douro estuary sand spit nw portugal is an important natural defence against the impact of storm events aiming to improve navigation safety a breakwater was built to stabilise the spit in 2001 a monitoring programme was set up to understand the dynamics of the sand spit and later to evaluate breakwater efficiency on stabilising the spit s shape and volume nine years of periodic accurate 3d digital elevation models obtained from kinematic differential global positioning system surveys were used to assess spatial and temporal changes in the spit morphology before and after the breakwater construction temporal and spatial spit dynamics were further related to river discharge flows wave action and wind energy although the breakwater had a stabilising effect on most of the spit s area and volume it caused a clear change in the morphology of the spit s head and in the previously observed patterns of erosion and accretion before breakwater construction erosion was significantly correlated with extreme river discharge and wind conditions accretion was significantly correlated with extreme wind conditions and spit area and volume at 1 2 m elevation with extreme wave conditions after breakwater construction these correlations were not found but the eastern inland face of the spit and particularly its southern part became more susceptible to the observed extreme river discharge flows wave and wind conditions the instability in the se part of the spit may pose a threat to an existing local nature reserve furthermore before breakwater construction the spit often breached during severe floods favouring river discharges the strengthening of the spit after breakwater construction may reduce the likelihood of breaching and lead to more severe flood effects in the estuary

heterogeneity patterns of quaternary glaciofluvial gravel bodies sw germany application to hydrogeology abstract the architecture of sedimentary bodies determines the heterogeneity of many aquifers thus for environmental risk assessment and quantification of clean up efficiencies determination of the spatial distribution of hydraulic properties is required in this study outcrop analogues of glaciofluvial gravel bed deposits are used for a process based analysis of sedimentary heterogeneities which in turn are transformed into hydraulic parameters three scales of heterogeneities are distinguished a the lithofacies scale is formed by unique transport and depositional processes that form the fundamental building blocks hydrofacies types b the depositional element scale shows distinct geometrical characteristics internal structure and bounding surfaces and determines the local distribution of lithofacies and hence the correlation structure of permeabilities c the architectural scale of gravel bodies is formed by the stacking of depositional elements which is controlled by the dynamics of aggrading paleofluvial systems comparison of numerous gravel pits in sw germany revealed three major architectural patterns of glaciofluvial gravel bodies that can be distinguished statistically by the preservation of depositional elements as well as the frequency of lithofacies types the facies analysis results in three conceptual facies models of proglacial river systems which are regionally classified as main intermediate and minor discharge types based on calculated and laboratory measured hydraulic properties of the various lithofacies types detailed outcrop wall maps were digitized into polygons of defined hydrofacies types by using the gis system arc info the two dimensional fields of hydraulic properties were then transferred into a numerical model of groundwater flow modeling results clearly illustrate that the three heterogeneity patterns of gravel bodies also have distinguishable hydraulic response characteristics

critical storm thresholds for morphological changes in the western black sea coastal zone abstract storms are one of the phenomena determining the short term evolution of coasts by influencing the erosion and accretion patterns of the beaches some severe storms could cause loss of beach sediments partial or complete destruction of coastal structures and even threaten human life and occupation bearing this in mind it is essential to comprehend which storms could evoke transient although in some instances significant morphological changes and which could be considered as hazardous and result in catastrophic damage this issue implies establishment of a set of critical thresholds for storm impact on coastal morphology the paper presents a regional scale analysis of the near shore morphological response of five beaches to storms of varying intensity the analysis is accomplished by coupling of offshore wave and cross shore profile data obtained for the bulgarian black sea coast the historical storm pattern is reconstructed through hindcast using a coupled wave model system while resulting morphological changes such as shoreline alteration and cross shore profile evolution are estimated by analysis of long term series of coastal measurements performed in 1970 1977 and 2008 2010 the storm impact thresholds are set in terms of integral wave energy taking into account both storm pattern and duration it was found that the morphological response to storm impact is site specific and single value thresholds are difficult to be established even at regional scale nevertheless a range of critical storm thresholds is proposed thus storms with integral wave energy varying within threshold values 0 4 0 7 10 6 j m 2 are regarded as capable of significant morphological changes while less energetic events are supposed to influence predominately the seasonal beach dynamics furthermore storms with integral wave energy higher than 0 7 10 6 j m 2 represent potentially destructive events that can change irreversibly the beach pattern or damage impact

extreme erosion on high energy embayed beaches influence of megarips and storm grouping abstract megarips have long been recognised as an important yet poorly documented mechanism of beach erosion on high energy embayed beaches the persistence and cumulative effect of megarips during storm groups are described from three embayed beaches arrifana mt clerigo and amoreira exposed to high energy wave conditions in the mesotidal bedrock dominated southwestern coast of portugal morphological changes determined by topographic monitoring and supplemented by interpretation of digital imagery over two years revealed the development of storm induced megarips which exerted a major influence on beach erosion differences in megarip influence within and between beaches are related to embayment geometry and orientation which significantly influence the nearshore wave field rip location is topographically controlled being determined by alongshore variations in breaking wave height and obliquity along with interaction of wave driven circulation patterns and embayment nearshore topography moderate beach sand loss during individual storms was linked to the development of megarips with associated rip neck and feeder channels extreme erosion however occurred when megarips and feeder channels persisted during successive storms promoting continued erosion and seaward sediment export observations show that once initiated megarip channels persist for several months and continue to act as conduits for offshore sediment transport under non storm conditions the maintenance of such rip circulation systems driven by morphodynamic feedback reduces beach recovery ability until the rip neck and feeder channels are infilled

mechanisms associated with the erosion of sand dune cliffs magilligan northern ireland a fifteen year history of coastal dune recession at magilligan northern ireland has revealed both time and space contrasts in processes and morphology since 1968 storm frequency has increased while dune retreat reached a peak 5 4 m in 1978 1979 three types of dune eroding events are noted resulting from particular wave wind tide combinations the spatial variability in dune scarping is associated with vegetation and soil development and slope failures range from granular avalanches to retrogressive rotational slumps

iceberg hosted nanoparticulate fe in the southern ocean mineralogy origin dissolution kinetics and source of bioavailable fe abstract sediments from icebergs and glaciers contain nanopartculate fe iii oxyhydroxides including ferrihydrite which form in aqueous oxic micro environments where fe ii bearing rock minerals oxidise and high degrees of supersaturation are promoted by freezing and thawing an ascorbic acid extraction dissolves only labile fe present in fresh loosely aggregated ferrihydrite that is directly or indirectly bioavailable glacial and iceberg sediments contain ferrihydrite aggregates that provide 0 04 to 0 17 fe soluble in ascorbic acid rather larger than the concentrations in a limited suite of atmospheric dusts the dissolution behaviour of labile fe from glacial and iceberg sediments by ascorbic acid is controlled by the access of reactant or removal of solute through micropores to or from active sites in the interior of ferrihydrite aggregates a first order kinetic model is presented to examine the rates at which bioavailable fe can be supplied by melting icebergs in the weddell sea the model utilizes rate constants from the literature for the processes which solubilise fe from nanoparticulate ferrihydrite dissolution photochemical reduction and grazing and the processes that remove fe nanoparticulates sinking scavenging and incorporation in faecal material and render them less reactive transformation aging model results demonstrate that icebergs can supply bioavailable fe to the weddell sea by the dissolution of nanoparticulate ferrihydrite despite loss removal of nanoparticles by sinking aging transformation scavenging and incorporation into faecal pellets at rates that are comparable to atmospheric dust dissolution enhanced by photochemical reduction and grazing provides the most rapid rates of bioavailable fe production

storms shoreface morphodynamics sand supply and the accretion and erosion of coastal dune barriers in the southern north sea abstract the coast of the southern north sea is bound by dune barriers that have developed adjacent to a shallow storm and tide dominated shoreface comprising numerous shore parallel to sub shore parallel tidal sand banks the banks evolve under the joint control of tide wave and wind induced shore parallel currents which tend to stretch them eventually leading to bank division and to shoaling and breaking storm waves which tend to drive them ashore the banks thus modulate the delivery of storm wave energy to the coast redirect currents alongshore and are the sand sources for the accretion of coastal dunes foredune accretion occurs where major sand banks have migrated shoreward over the last centuries to be finally driven ashore and weld under the impact of storm waves morphological changes in the bank field can impact on shoreline stability through dissipation or enhanced shoreward transmission of storm wave energy and effects on radiation stress particularly when waves are breaking over the banks where banks are close to the shore mitigation of offshore sediment transport especially during storms can occur because of gradients in radiation stress generated by the complex 3d bank structure these macro scale mechanisms involve embedded meso scale interactions that revolve around the mobility of sand waves mobility of beach bars and troughs and foredune mobility and micro scale processes of bedform mobility in the subaqueous and intertidal domains and of swash and aeolian beach dune sand transport these embedded interactions and the morphodynamic feedback loops illustrate the importance of synchroneity of sand transport from shoreface to dune on this coast large stretches of the foredunes show either signs of stability or mild but chronic erosion furthermore a demonstrated lack of a clear relationship occurs between storminess and coastal response over the second half of the 20th century the present situation may be indicative of conditions of rather limited sand supply from offshore notwithstanding the abundance of sand on the nearby shallow shoreface except in areas where a nearshore storm driven tidal sand bank has become shore attached apart from the important influence of shoreface sand banks and of wave bank interactions foredune accretion and erosion also depend on various context controls that include individual storm characteristics wind speed and incidence relative to the shore tidal stage during storms and direct human intervention on the shore through foredune and beach management the bewildering variability inherent in these intricately related parameters may also explain the poor relationship between storminess and barrier shoreline change and will still continue to render unpredictable the response of shores to individual storms

identifying storm impacts on an embayed high energy coastline examples from western ireland abstract large sections of the western irish coast are characterised by a highly compartmentalised series of headland embayment cells in which sand and gravel beaches are backed by large vegetated dune systems exposure to modally high energy swell renders most of these beaches dissipative in character a mesotidal range c 3 5 4 5 m exists along much of the coast analysis of instrumental wind records from three locations permitted the identification of a variety of storm types and the construction of storm catalogues few individual storms were recorded at all three stations indicating a lack of regional consistency in storm record of the total storms recorded only a small percentage are potentially damaging onshore directed and even fewer span a high tide and thus potentially induce a measurable morphological response at the coast through a combination of historical records meteorological records field observations and wave modelling we attempt to assess the impact of storms quantifiable records of coastal morphology maps air photos and beach profiles are few in number and do not generally record responses that may be definitely attributed to specific storms numerical wave simulations and observations at a variety of sites on the west irish coast however provide insights into instantaneous and medium term decadal storm responses in such systems we argue that beaches and dunes that are attuned to modally high energy regimes require extreme storms to cause significant morphological impact the varying orientation of beaches a spatially nonuniform storm catalogue and the need for a storm to occur at high water to produce measurable change impart site specific storm susceptibility to these embayments furthermore we argue that long period wave energy attenuation across dissipative shorefaces and beaches reduces coastal response to distant storms whereas short period locally generated wind waves are more likely to cause major dune and beach erosion as they arrive at the shoreline unrefracted this apparently variable response of beach and dune systems to storm forcing at a decadal scale over a coastline length of 200 km urges caution in generalising regarding regional scale coastal responses to climatic change

the use of the natural gamma log in engineering geological investigations the natural gamma log is widely used in both cased and uncased boreholes to identify changes in lithology down the length of a borehole this is particularly important in the ground investigation process where 100 core recovery is often not achieved in the borehole programme in this paper the use of the gamma log to provide additional information from the ground investigation boreholes is examined and illustrated by a number of case histories it is shown that the gamma log can be used to study both the lithological variations within an individual borehole and changes in geological structure across a construction site it is also demonstrated that a geological formation or sequence can be classified in terms of its natural gamma signature which enables the geologist to observe its presence over large distances on a regional basis the importance of the calibration of the gamma sonde and the use of the correct logging speed is emphasised in the paper the successful calibration of the log against a quarry wall using a known observed geological structure as a reference is also described together with the use of the resulting information to obtain a geological log for boreholes drilled behind the quarry face its use in extrapolating between boreholes to detect and trace the presence of a particular geological formation to estimate its vertical and lateral extent for possible extraction is also discussed

geostatistical analysis of aquifer heterogeneity from the core scale to the basin scale a case study this study examines the spatial variability of conductivity within the sandstone wabiskaw member of the lower cretaceous middle mannville in the alberta basin the wabiskaw is an important regional hydrostratigraphic unit vertical variability within the aquifer is characterized by downhole variograms of log conductivity from core measurements they are found to exhibit pseudoperiodic structures due to alternating sand and shale layers horizontal spatial variability is characterized using variograms of log transmissivity and indicator data these variograms show a steady increase in spatial variability over length scales ranging from 400 m to 100 km characteristic of self similar or fractal behavior they also reveal distinct correlation structures related to both high and low transmissivity depositional features this study also considers the upscaling of conductivity vertically from the core to the well scale and horizontally from the well to the basin scale it is shown that traditional vertical upscaling of conductivities by arithmetic averaging causes an overestimation of transmissivity in two dimensional areal flow models an alternative approach based on power averaging is proposed transmissivities derived by vertical upscaling of core measurements are compared with values derived from drill stem tests in the same well no correlation between these quantities is observed an average transmissivity for the wabiskaw in the study area is determined by geometric spatial averaging however the highly clustered spatial distribution of well locations requires a weighting of sample values using ordinary kriging

potential coordinate mislocations in crosshole tomography results from the grimsel test site switzerland tomographic techniques based on borehole to borehole and tunnel to borehole traveltime data are now being employed in a wide range of studies associated with the exploration and exploitation of hydrocarbons and metallic minerals the disposal of chemical and radioactive waste diverse civil engineering projects and archaeology a fundamental assumption of currently employed tomographic inversion strategies is that the coordinates of the boreholes and tunnels containing the seismic sources and receivers are accurately known by inverting both synthetic and observed traveltime data we demonstrate that relatively minor coordinate errors 1 2 in the deeper parts of long boreholes 100 m may produce artifacts in the tomographic images that are comparable in extent and amplitude to true velocity anomalies to address this problem we introduce the coupled inverse method commonly used in earthquake studies as a means to determine simultaneously borehole coordinate adjustments and an estimate of the tomog

derivation of site specific relationships between hydraulic parameters and p wave velocities based on hydraulic and seismic tomography derivation of site specific relationships between hydraulic parameters and p wave velocities based on hydraulic and seismic tomography brauchler r 1 doetsch j 1 2 dietrich p 3 sauter m 4 eth zurich department of earth sciences sonneggstrasse 5 8092 zurich switzerland now at earth sciences division lawrence berkeley national laboratory one cyclotron road berkeley ca 94720 ufz helmholtz centre for environmental research department monitoring and exploration technologies permoserstrasse 15 04318 leipzig germany geoscientific centre university of gottingen goldschmidtstrase 3 37077 gottingen germany

storminess and vulnerability along the atlantic coastlines of europe analysis of storm records and of a greenhouse gases induced climate scenario abstract identification of the distinctive circulation patterns of storminess on the atlantic margin of europe forms the main objective of this study dealing with storm frequency intensity and tracking the climatology of the extratropical cyclones that affect this region has been examined for the period 1940 1998 coastal meteorological data from ireland to spain have been linked to the cyclone history for the north atlantic in the analysis of storm records for european coasts the study examines the evolution in the occurrence of storms since the 1940s and also their relationship with the north atlantic oscillation nao results indicate a seasonal shift in the wind climate with regionally more severe winters and calmer summers established this pattern appears to be linked to a northward displacement in the main north atlantic cyclone track an experiment with the echam4 a gcm at high resolution t106 has also been used to model the effect of a greenhouse gases induced warming climate on the climatology of coastal storms in the region the experiment consists of 1 a 30 year control time slice representing present day equivalent co 2 concentrations and 2 a 30 year perturbed period corresponding to a time when the radiative forcing has doubled in terms of equivalent co 2 concentrations the boundary conditions have been obtained from an atmosphere ocean coupled oa gcm simulation at low horizontal resolution an algorithm was developed to allow the identification of individual cyclone movements in selected coastal zones for most of the northern part of the study region covering ireland and scotland results describe the establishment by ca 2060 of a tendency for fewer but more intense storms the impacts of these changes in storminess for the vulnerability of european atlantic coasts are considered for low lying exposed and soft sedimentary coasts as in ireland these changes in storminess are likely to result in significant localised increases in coastal erosion

joint application of surface electrical resistivity and gpr measurements for groundwater exploration on the island of spiekeroog northern germany geophysical surveys have been carried out on the east frisian island of spiekeroog at the german north sea coast in 1996 so called freshwater lenses lying on top of saltwater saturated layers because of their lower density provide most of the freshwater supply on the frisian islands the major goal of the present study is to show the possibilities of a joint application of surface electrical resistivity soundings and ground penetrating radar gpr for the hydrogeological investigation of the island it is shown that a comprehensive interpretation of large scale gpr profiling data in a sandy aquifer provides valuable hydrogeological information especially if there is not any other information available such as from boreholes or groundwater measuring points applying the techniques of surface electrical resistivity and ground penetrating radar jointly we were able to construct a groundwater contour map for the entire island of spiekeroog in addition we were able to delineate hydrogeologically important changes in grain size and stratigraphical features and to indicate temporal changes of the spatial extent of the freshwater reservoir in comparison to earlier less complete investigations finally we located an area previously unknown in the eastern part of the island where precipitation appears to be developing a substantial new freshwater lens

the evolution of the southern margin of the east european craton based on seismic and potential field data abstract this paper presents an integrated geophysical study of the southern margin of the east european craton eec in the karpinksy swell north caucasus area it presents new interpretations of deep refraction and wide angle reflection deep seismic sounding dss data as well as conventional seismic and cdp profiling and new analyses of potential field data including three dimensional gravity and magnetic modelling an integrated model of the physical properties and structure of the earth s crust and partially upper mantle displays distinct features that are related to tectonic history of the study area the voronezh massif vm the ukrainian shield and rostov dome rd of the eec as well as the donbas foldbelt df karpinsky swell ks scythian plate sp and precaspian basin pcb constitute the geodynamic ensemble that developed on the southern margin of the continent baltica there proposed evolutionary model comprises a stage of rifting during the middle to late devonian post rift extension and subsidence during carboniferous early permian times synchronous with and related to the southward displacement of the rostov dome and extension in a palaeo scythian back arc basin and subsequent mesozoic and younger evolution a pre ordovician possibly riphean mafic magmatic complex is inferred on a near vertical reflection seismic cross section through the western portion of the astrakhan dome in the southwest part of the precaspian basin this complex combined with evidence of a subducting slab in the upper mantle imply the presence of pre ordovician riphean island arc with synchronous extension in a precaspian back arc basin is suggested a middle palaeozoic back arc basin ensemble in what is now the western karpinsky swell was more than 100 km to the south from its present location the stavropol high migrated northwards dislocating and moving fragments of this back arc basin sometime thereafter linear positive magnetic anomalies reflect the position of associated faults which define the location of the eastern segment of the karpinsky swell these faults which dip northward are recognised on crustal dss profiles crossing the donbas foldbelt and scythian plate they are interpreted in terms of compressional tectonics younger than the hercynian stage of evolution i e post palaeozoic

quantitative integration of hydrogeophysical data conditional geostatistical simulation for characterizing heterogeneous alluvial aquifers high resolution geophysical parameter information as it can be provided for example by crosshole georadar and seismic tomography has proven to provide useful spatial information to complement traditional hydrological methods such as core analyses logging techniques and tracer or pumping tests quantitative integration of these diverse database components is one of the major challenges in the field of high resolution hydrogeophysics because of their different scales of measurement and the usually weak petrophysical relations among the measurements in this study we systematically explore the usefulness of a conditional stochastic simulation approach based on simulated annealing for this purpose first we generate a realistic model of an alluvial aquifer consisting of a 2d scale invariant porosity field on the basis of this model we generate synthetic neutron porosity logs and crosshole georadar tomographic surveys we then use the proposed geostatistical simulation approach to integrate this hydr

storm response and beach rotation on a gravel beach slapton sands u k abstract continuous argus video data and fortnightly measurements of subaerial morphology were obtained over a 3 year period from a steep macrotidal gravel beach on the southwest coast of the u k concurrent wave and water level data were also collected enabling the correlation of the observed morphological changes to the hydrodynamic forcing wave conditions are generally low h s 0 5 1 m but the beach is affected by frequent storm wave activity c 15 storms per year with h s 2 4 m with waves either approaching from the south swell waves or from the east wind waves an assessment of the three dimensional morphological response of the beach to the two typical storm types was carried out by analysing the impact of 27 storms that occurred from april 2007 to april 2009 southerly storms cause accretion of the supratidal zone and erosion of the intertidal zone and a significant loss in overall beach volume easterly storms on the other hand induce supratidal erosion and intertidal accretion and a significant gain in overall beach volume during the intervening calm periods a small supratidal berm is constructed and a modest gain in overall beach volume occurs wave modelling indicated that opposing longshore energy fluxes occur for the different storm types with a northerly energy flux during southerly storms and a southerly flux during easterly storms weekly shorelines derived from the argus images revealed that the northern end of the beach widened by c 30 m and the middle beach receded by c 40 m over a relatively brief period a few months the occurrence of this beach rotation event is attributed to a higher frequency of southerly storms and or a lower frequency of easterly storms over this period thus the development and stability of the beach on annual time scales depend on the relative contributions of the two storm types and their sequencing longshore sediment transport lst rates derived from the data on beach morphological change were compared with several littoral drift formulae previously applied to gravel beaches the cerc equation with a proportionality factor k between littoral drift rate i l and longshore wave energy flux p l of k 0 054 yielded the best results

a 7600 year sedimentary record of climatic instability in dunnet bay north scotland abstract we present a partial reconstruction of ne atlantic climatic variability the first based on stratigraphic evidence obtained from a vegetated dune system of the northern scottish coast the dune system at dunnet bay is fringed by prominent submerged peat deposits exposed only at low tide which record stable climatic periods when lower energy wind regimes prevailed allowing the formation of organic soils by contrast periods of sand influx are associated with high energy conditions the majority of sand material tested had a narrow range of particle sizes and major element composition supporting the interpretation of a common aeolian origin sand layers were dated with optically stimulated luminescence osl and peat layers were 14 c dated in four cores c1 c4 and seven sample sections s1 s7 the results from the two master sections s1 and s2 1 km apart indicate synchronous episodes of climatic stability 7650 6310 4340 4000 2690 2290 100 0 cal a bp and instability 6310 4340 4000 2690 2290 2000 170 100 cal a bp in spite of very different mean accumulation rates at the two sites 1 mm a 1 at s1 and 0 2 mm a 1 at s2 phases of sand deposition i e aeolian activity at dunnet tend to be associated with high average levels of chloride in the greenland ice sheet project 2 ice core gisp2 phases of peat development show a fairly good correspondence with low ice rafting activity in the ne atlantic and with indicators of wetness measured from a peat bog in sw sweden by contrast comparison of the dunnet depositional timeline with other regional studies e g hebrides and orkney shows little synchronicity this suggests that a local scale variables have a strong effect on regional patterns of dune instability and b the geological and geographic settings of dunnet bay mean that only large climatic regime shifts in the ne atlantic are capable of triggering instability and being preserved in the depositional record

decadal behavior of tidal inlet associated beach systems northwest ireland in relation to climate forcing abstract shoreline and ebb channel evolution between 1834 and 2008 was recorded at three embayed beaches in northwest ireland with historically stable relative sea level the beaches are geologically constrained within bedrock valleys and have minimal contemporary sediment input their behavior is strongly influenced by tidal inlet dynamics of adjacent estuaries major observed changes in shoreline position are linked to fluctuations in inlet ebb channel orientation comparison of the available historical record of geomorphological change with instrumental and proxy climate records suggests that inlet changes may be driven by fluctuations in average storminess periods of high storminess perturb the inlet system causing major changes in ebb channel configuration after which sediment redistribution returns the system to its former state over a prolonged period years to decades

discharge of hydrothermal fluids through sediment at the escanaba trough gorda ridge odp leg 169 assessing the effects on the rock magnetic signal an integrated rock magnetic and multivariate statistical analysis of a suite of sediment samples recovered from odp sites 1037 and 1038 leg 169 escanaba trough gorda ridge spreading center ne pacific ocean has been carried out to assess the use of the sediment magnetic signal as a tracer of post depositional alteration related to the discharge of hydrothermal fluids through these sediments the uppermost above 40 mbsf section of three separate holes holes 1037 b 1038 i and 1038 g was sampled previous sedimentological and geochemical studies indicated that these holes represent a transect from unaltered to strongly hydrothermally influenced sediments analysis of nrm arm anisotropy of magnetic susceptibility ams hysteresis parameters and low temperature magnetic properties suggest increasing alteration of the magnetic minerals with increasing circulation of hydrothermal circulation of fluids fuzzy c means clustering combined with non linear mapping yields a more elaborate picture because similar alteration groupings at different holes can be compared at hole 1037 b a sedimentary reference site drilled away from the area of high heat flow the rock magnetic signal is a sensitive record of changes in detrital inputs magnetite and some monoclinic pyrrhotite are detected the detrital magnetic signal is still apparent at intermediate hole 1038 i but cluster analysis detects an increasing hydrothermal influence on the magnetomineralogy in the lower part of the hole strong hydrothermal alteration at hole 1038 g results in a complete loss of the detrital diagenetic magnetic signal which is replaced by a much weaker hydrothermal signal composed of monoclinic pyrrhotite and pyrite the alteration of the magnetic signal is not restricted to the uppermost few meters of the sediment column and the magnetic properties of the sediment can be used to trace even minor alterations of marine sediments related to the lateral and vertical advection of hydrothermal fluids which may easily be overlooked by more traditional methods fl 2000 elsevier science b v all rights reserved

storm induced damages along the catalan coast nw mediterranean during the period 1958 2008 abstract the temporal and spatial patterns of storm induced damage along the catalan coast nw mediterranean during the last 50 years have been analyzed to identify main climatic and non climatic forcings in the absence of systematic data a storm induced damage database compiled from press news has been built which together with an intensity scale has allowed us to characterize the frequency and intensity of damage although no temporal trend has been detected in storm induced hazards coastal damage has increased at a rate of about 40 per decade during the last 50 years along the catalan coast the main non climatic factors identified controlling this trend were the urban growth along the coastal fringe and the generalized erosive behavior of beaches the first one increased values at risk and the second one increased their exposure to storm induced hazards in spite of the importance of non climatic factors to modulate coastal damage an exponential dependence of damages on storm induced inundation and erosion was detected in addition to this storm induced geomorphic changes along the ebro delta coast have also been analyzed during the period analyzed harmful storms seem to be clustered with most of the events being present in the late 1990s and especially from 2001 to 2004 resulting in frequent events of intense beach barrier breaching massive overwash and flooding they are mainly expressed in sensitive areas which are subject to long term erosional processes and comprise a low lying profile and a narrow beach this reflects the role of coastal morphology in controlling the intensity of storm induced hazards along the deltaic coast shoreline evolution rates calculated during this period were significantly larger than the previously recorded ones reflecting a pulsating erosion behavior where large pulses occur during stormy periods and are reduced during post storm periods under the present scenario of maximum coastal development storm induced damage has been reported almost every year which could indicate that the present overall beach configuration status along the catalan coast has reached its limit for protecting the hinterland against storms

stochastic inversion of tracer test and electrical geophysical data to estimate hydraulic conductivities 1 quantifying the spatial configuration of hydraulic conductivity k in heterogeneous geological environments is essential for accurate predictions of contaminant transport but is difficult because of the inherent limitations in resolution and coverage associated with traditional hydrological measurements to address this issue we consider crosshole and surface based electrical resistivity geophysical measurements collected in time during a saline tracer experiment we use a bayesian markov chain monte carlo mcmc methodology to jointly invert the dynamic resistivity data together with borehole tracer concentration data to generate multiple posterior realizations of k that are consistent with all available information we do this within a coupled inversion framework whereby the geophysical and hydrological forward models are linked through an uncertain relationship between electrical resistivity and concentration to minimize computational expense a facies based subsurface parameterization is developed the bayesian mcmc methodology allows us to explore the potential benefits of including the geophysical data into the inverse problem by examining their effect on our ability to identify fast flowpaths in the subsurface and their impact on hydrological prediction uncertainty using a complex geostatistically generated two dimensional numerical example representative of a fluvial environment we demonstrate that flow model calibration is improved and prediction error is decreased when the electrical resistivity data are included the worth of the geophysical data is found to be greatest for long spatial correlation lengths of subsurface heterogeneity with respect to wellbore separation where flow and transport are largely controlled by highly connected flowpaths

seasonal changes and morphodynamic behavior of a high energy mesotidal beach case study of charf el akab beach on the north atlantic coast of morocco the morphodynamic behavior of a mesotidal sandy beach was monitored during both calm and energetic conditions two years of seasonal surveys were carried out on charf el akab a gently sloped beach in the north atlantic coast of morocco the method of survey consisted of a 3d study of the beach morphological changes and provided 2 cm vertical accuracy during the surveyed period charf el akab beach underwent very energetic wave conditions and the breaking wave height was of h b 1 5 m the beach is characterized by a nonpermanent swash bar and composed of well sorted medium sand the application of environmental parameters revealed a dissipative state with very low beach gradient which did not vary significantly over the studied period morphological changes consist of beach erosion and bar decay under high energy waves whereas the intertidal bar re established and the beach recorded an accentuated accretion due to relatively fair weather conditions the beach volume reveals a seasonal behavior the sand accumulated during summer is dramatically removed during winter season the range in beach sand volume from the most accreted to the most eroded conditions observed is about 5 493 m3 the average sand volume flux between surveys reaches 1 and 0 4 m2 day during peak erosion and accretion periods the relationships between the wave forcing and the sand volume adjustments were examined the sand volume change was found to be highly correlated 0 91 with the wave energy flux the highest correspondence 0 95 was found between the sand flux rate and the wave energy flux the wave forcing is expected to be the main factor governing beach morphodynamics at charf el akab site

numerical modeling of borehole georadar data high frequency electromagnetic em wave propagation phenomena associated with borehole georadar experiments are complex to improve our understanding of the governing physical processes we present a finite difference solution of maxwell s equations in cylindrical coordinates this approach allows us to model the full em wavefield associated with borehole georadar experiments and to assess the adequacy of ray based methods currently used to interpret the observed amplitudes our results indicate that because shallow boreholes are often water filled the finite length of the boreholes as well as changes in material properties along a borehole wall can have major effects on the amplitude behavior of borehole georadar data as a result of waveguide phenomena the radiation pattern of a vertical electric dipole source located in a water filled borehole may be distorted significantly with respect to the corresponding reference radiation pattern in a homogeneous medium even greater distortions of the radiation pattern result when the electric dipole source is located near material boundaries or near the upper or lower end of a borehole this study indicates that some of the basic assumptions of conventional ray based amplitude tomography often are not fulfilled for borehole georadar data and that the derived constraints on the attenuation and conductivity structure should be regarded as qualitative in nature the algorithm and the results presented in this study do however offer the perspective to alleviate some of these inherent problems and thus help to make ray based georadar attenuation tomography a more reliable and effective tool for probing the shallow subsurface

variations in the response of the dune coast of northern france to major storms as a function of available beach sediment volume a series of airborne topographic lidar data were obtained from may 2008 to january 2014 over two coastal sites of northern france bay of wissant and east of dunkirk these data were used with wind and tide gauge measurements to assess the impacts of storms on beaches and coastal dunes and particularly of the series of major storms that hit western europe during the fall and early winter of 2013 our results show a high variability in shoreline response from one site to the other but also within each coastal site coastal dune erosion and shoreline retreat occurred at both sites particularly on the coast of the bay of wissant where shoreline retreat up to about 40 m was measured however stability or even shoreline advance were also observed despite the occurrence of an extreme water level with a return period 100 years during the storm xaver in early december 2013 comparison of shoreline change with variations of coastal dune and upper beach volumes revealed only weak relationships our results nevertheless showed that shoreline behavior seems to strongly depend on the initial sediment volume on the upper beach before the occurrence of the storms according to our measurements an upper beach volume of about 30 m3 m 1 between the dune toe and the mean high water level is sufficient at these sites to protect the coastal dunes from storm waves associated with high water levels with return periods 10 years the identification of such thresholds in terms of upper beach width or sediment volume may represent valuable information for improving the management of shoreline change by providing an estimate of the minimum quantity of sand on the upper beach necessary to ensure shoreline stability in this region copyright 2016 john wiley sons ltd

a comparison of the post storm recovery of two sandy beaches on hong kong island southern china abstract typhoon hagupit was one of six tropical cyclones that affected hong kong in 2008 when the typhoon made landfall the combined effect of the waves storm surge and seasonal high tides resulted in a maximum sea level of 3 53 m at the nearest tide gauge to the study site the highest since 1962 the event caused considerable damage to coastal infrastructure and large scale erosion on many sandy beaches in hong kong to study the degree of erosion and recovery of hong kong beaches we surveyed two sandy beaches tai long wan tlw a relatively high energy exposed beach system and to tei wan ttw a relatively low energy sheltered beach system we examined the two beaches for changes in their beach profiles and sediment properties tlw recovered quickly with significant post storm accretion of fine to medium grained sand within four months after the typhoon tlw regained 700 m 3 sand forming a new 1 0 m high berm with the beach face prograding approximately 5 0 m seaward in contrast within the same four months after the typhoon ttw showed little evidence of sand accretion or recovery with only minor changes in the beach profile in fact instead of post storm sand accretion the landward migration of the high tide mark shown in the pre and post storm satellite images suggested that the post storm beach elevation at ttw decreased the results which reflect the different background energy regimes of each beach indicate that different coastal management strategies should be applied in the case of relatively high energy beaches of hong kong we suggest not interfering with their natural state in contrast in the case of relatively low energy beaches of hong kong which appear unlikely to recover rapidly from erosion during storms we suggest further investigation before applying any long to medium term management strategies

in situ exhumation from bedrock of large rounded boulders at the giant s causeway northern ireland an alternative genesis for large shore boulders mega clasts abstract very large boulders mega clasts are found on some coasts the size and position of the boulders has been used to suggest that contemporary marine processes acting within their normal spatial and energy range are unlikely to have moved them explanations for the presence of such boulders include transport by infrequent very high energy marine processes storms or tsunamis mass movement from backing cliffs transport by ice or exhumation from glacial deposits this paper advances an alternative explanation which does not involve transport by any of the marine or glacial processes or gravity it is proposed that in a very specific geological and topographic setting large boulders are exhumed in situ by storm waves acting on heavily weathered jointed basalts eventually wave action liberates residual blocks from the deeply weathered matrix these liberated boulders will be mobile only if they lie within wave competence and the larger ones will remain as stationary residuals the same in situ weathering processes followed by removal of the friable matrix material debris by wave action also progressively round the boulders consequently despite their appearance of being transport rounded the larger boulders have not transported at all in specific locations the assumption that the presence and rounding of such large clasts in the shore zone can be attributed to marine transport can lead to erroneous interpretations of very high energy storm wave or tsunami activity

coastal monitoring solutions of the geomorphological response of beach dune systems using multi temporal lidar datasets vendee coast france abstract three beach and dune systems located in the northeastern part of the bay of biscay in france were monitored over 5 years with a time series of three airborne lidar datasets the three study sites illustrate a variety of morphological beach types found in this region reproducible monitoring solutions adapted to basic and complex beach and dune morphologies using lidar time series were investigated over two periods bounded by the three surveys the first period between may 2008 and august 2010 is characterized by a higher prevalence of storm events and thus has a greater potential for eroding the coast than the second period between august 2010 and september 2013 during the first period the central and northeastern part of the bay of biscay was notably impacted by storm xynthia with water levels and wave heights exceeding the 10 year return period and 1 year return period respectively despite differences in dune morphology between the sites the dune crest dhigh and the dune base dlow are efficiently extracted from each dem based on the extracted dune base an original shoreline mobility indicator is built displaying a combination of the horizontal and vertical migrations of this geomorphic indicator between two lidar datasets a geomorphic change detection is also completed by computing dems of difference dod resulting in segregated maps of erosion and deposition and sediment budgets accounting for the accuracy of lidar datasets a probabilistic approach at a 95 confidence interval is used as a threshold for the geomorphic change detection showing more reliable results however caution should be taken when interpreting thresholded maps of changes and sediment budgets because some beach processes may be masked especially on wide tidal beaches by only keeping the most significant changes the results of the shoreline mobility and geomorphic change detection show a high variability in the beach responses between and within the three study sites explained mainly by beach orientation and local factors despite variable site specific mechanisms the recovery processes redistribute the available sand more on the upper parts of the beach producing significant deposition generally in the form of embryo dunes the monitoring of the beach and dune systems with airborne lidar datasets reveals that the three study sites show diverse behaviours during the first period likely associated with storms while the analysis show more homogenous beach responses during the second period likely associated with a recovery phase

joint inversion of geophysical data summary by jointly inverting several different kinds of geophysical measurements at a site we avoid some of the ambiguity inherent in the individual methods we show how this can be done for the combination of dc resistivity and magnetotelluric measurements on a layered medium by considering a simple 3 layer model the combination resolves the resistivity of the thin resistive second layer even though neither of the two methods can do so alone the method is then applied to field data from a shallow sedimentary basin a blind zone occurs beneath a thick near surface conductive shale by a study of the eigenvalue structure of the model it can be seen that resolution in this zone would be slightly enhanced by higher frequency magnetotelluric data but additional dc data at larger spacing would yield no improvement

storm swash terraces a previously overlooked element of the cliff shore platform system storm swash terraces are a distinctive and previously unreported component of the cliff shore platform sedimentary system they consist of laminated marine sands and gravels with occasional large rounded clasts and fine muddy laminae the planar deposits dip gently seaward are up to 1 m thick at the seaward margin and thin landwards forming a wedge they are laterally continuous over tens of meters in a coast parallel dimension they occur in coastal re entrants at the rear of boulder beaches and shore platforms at elevations between 1 and 9 m above contemporary high tide level the terrace sediments represent deposition at the limit of wave run up during extreme storms during such events wave energy is largely dissipated by a shore platform and or boulder beach but sufficient energy remains to carry water and fine sediment to higher levels where it then accumulates the deposition and preservation of storm swash terraces depend on a coastal topography that combines partial wave energy dissipation on a shore platform or boulder beach with available depositional space to landwards these deposits contain a sedimentary record of past storminess on high energy coasts that has yet to be exploited

concepts in gravel beach dynamics abstract the dominant processes in gravel beach dynamics are reviewed highlighting some common themes which unify the various components of the gravel beach system the repercussions of which impart on how gravel beach dynamics might be understood conceptually in particular gravel beach dynamics are thought to be highly dependent on the temporal and spatial variation in grain size and the continual adjustments made by an active beach step both of which act not only as the expression of changing morphodynamic conditions but also as a controlling influence morphodynamics the notion that the exchanges on beaches between the hydrodynamics sediment transport and morphological change takes the form of reciprocal relationships which are mediated through feedback mechanisms in such a way that they cannot be thought of or studied independently is not a new one yet it appears that for the gravel beach morphodynamics must be re defined to describe conditions where variations in sediment size are thought to deserve parity rather than as merely a sequent entity or boundary condition morpho sedimentary dynamics is a phrase coined to intuit such cause and effect detailing the co evolution of morphology hydro hydraulics and sediment properties whilst acknowledging causative pluralism feedbacks and multiplier effects this is the recommended conceptual framework within which to crystallise thought and organise further research for the gravel beach essentially it increases the minimum number of parameters needed to describe the state of the gravel beach as a physical system therefore it is advised that simplicity will be most expedient in our future modelling efforts if complexity is to be adequately encapsulated

multivariate analysis of cross hole georadar velocity and attenuation tomograms for aquifer zonation 1 we have investigated the potential of combining cross hole georadar velocity and attenuation tomography as a method for characterizing heterogeneous alluvial aquifers a multivariate statistical technique known as k means cluster analysis is used to correlate and integrate information contained in velocity and attenuation tomograms cluster analysis allows us to identify objectively the major common trends in the tomographic data and thus to reduce the information to a limited number of characteristic parameter combinations the application of this procedure to two synthetic data sets indicates that it is a powerful tool for converting the complex relationships between the tomographically derived velocity and attenuation structures into a lithologically and hydrologically meaningful zonation of the probed region in addition these synthetic examples allow us to evaluate the reliability of further petrophysical parameter estimates we find that although absolute values of the tomographically inferred petrophysical parameters often differ significantly from the actual parameters the clustering approach enables us to reliably identify the major trends in the petrophysical properties finally we have applied the approach to a cross hole georadar data set collected in a well studied alluvial aquifer a comparison of the clustered tomographic section with well log data demonstrates that our approach delineates the hydrostratigraphic zonation

classification of beach response to extreme storms abstract extreme storms are responsible for rapid changes to coastlines worldwide during the 2013 14 winter the west coast of europe experienced a sequence of large storm induced wave events representing the most energetic period of waves in the last 60 years the southwest coast of england underwent significant geomorphological change during that period but exhibited a range of spatially variable and complex morphological responses despite being subjected to the same storm sequence here we use the 2013 14 storm response along the southwest coast of england as a natural field laboratory and explain this variability in storm response through the introduction and evaluation of a new classification of how sandy and gravel beaches respond to extreme storms cluster analysis was conducted using an unique data set of pre and post storm airborne light detection and ranging lidar data from 157 beach sites based on the net volumetric change dqnet and a novel parameter the longshore variation index lvi which quantifies the alongshore morphological variability in beach response four main beach response types were identified 1 fully exposed beaches that experienced large and alongshore uniform sediment losses dqnet 100 m3 m 1 2 semi exposed beaches that experienced medium alongshore uniform sediment losses dqnet 50 m3 m 1 3 sheltered short beaches that experienced limited net sediment change and alongshore variability in beach response and 4 sheltered long beaches that experienced considerable alongshore variability in beach response and large gross sediment change but limited net sediment change the key factors in determining the type of beach response are exposure to the storm waves angle of storm wave approach and the degree to which the beach is embayed these factors are universally applicable on many exposed coastlines worldwide so the response classification presented here is expected to be widely applicable

surficial beach structures formed by wave generated foam in this article we report on the modification of an intertidal beach surface by processes connected with the generation and redistribution of foam during a coastal storm foam generated by breaking waves initially accumulated at the swash line but was reworked across the beach by onshore winds a distinctive suite of sedimentary structures capable of preservation in the geological record was produced that displayed a distinctive cross shore arrangement from the zone of foam generation to the zone of foam deposition and also varied according to tidal level and wind speed foam marks with wind transverse linear elements characterized the upper sections of the beach other distinctive features formed during this storm include foam swash lines wind parallel foam stripes mud drapes and sand drapes on the upper beach and supratidal zone these features formed a surface veneer on a high energy dissipative beach their formation began during a high tide and continued during the subsequent falling tide during the later stages of the falling tide still forming foam driven features were in places being modified by and themselves modifying surface features characteristic of late stage emergence runoff e g double crested ripples rill marks microdeltas

response of wave dominated and mixed energy barriers to storms wave dominated and mixed energy barriers are extremely dynamic landforms responding to processes operating over a spectrum of time scales ranging from daily to monthly fluctuations related to storm and post storm conditions to century to millennium scale evolution driven by relative sea level change two types of storms are of particular relevance warm core tropical and cold core extratropical cyclones both are responsible for generating very large waves highly energetic surf zone dynamics and sediment transport elevated inshore water levels and extensive morphological responses all cyclones are affected by climate change which governs their frequency intensity and tracks barrier storm response is primarily governed by maximum storm runup and barrier morphology as conceptualised in abby sallenger s storm impact scale model sallenger 2000 this model defines four storm impact regimes and includes erosive as well as accretionary responses on the erosion side the swash regime drives bar and berm flattening the collision regime is marked by dune scarping and beach lowe the overwash regime leads to dune scouring and channel incision and the inundation regime may result in barrier destruction on the deposition side storm berms and beach ridges may form and accrete in the swash and collision regimes localised vertical beach and barrier accretion are associated with the collision and overwash regimes and washover deposition takes place in the overwash and inundation regimes site specific factors play a key role in moderating the morphological response and include storm characteristics type duration and track longshore sediment supply upwelling downwelling currents coastal setting and inner shelf topography the response of a barrier to a tropical or extratropical cyclone can however not be considered in isolation and has to be appreciated in a longer temporal context involving morphological preconditioning due to antecedent wave and water level conditions additionally a simple process response approach of the cause and effect type is inappropriate and a more complex conceptual framework involving thresholds feedbacks resilience and vulnerability will need to be adopted a useful way to visualise and conceptualise more complex storm behaviours and the longer term vulnerability of barriers is the resilience trajectory which maps out the changes in barrier geometry elevation and width over various time scales from weeks to years or even longer and under varying forcing conditions including changes in storminess and sea level rise an increased understanding of barrier response to storms and sequences of storms is required to better quantify long term barrier response to climate change high resolution and comprehensive decadal records of barrier response to storms are a prerequisite to achieve this ambition linking site specific coastal settings hydrodynamic drivers and morphological responses and allowing the recognition of recovery and impact dominated phases the enhanced insights in barrier response to extreme events must then be incorporated into improved coastal response models to help predict the impacts of future climate change on wave dominated and mixed energy barriers around the world 2013 elsevier b v

sub tidal ebb shoal control of shoreline erosion via wave refraction magilligan foreland northern ireland abstract a wave refraction model is used to examine the effects of sub tidal ebb shoal elongation on the erosion of the adjacent coast at magilligan northern ireland as deep water wave approach angles are stepped at 10 intervals from nw to ne so the shoal controls the position of breaker convergence zones which migrate nw along the shore but at a decreasing rate prolonged refraction of unidirectional swell is thought to be responsible for the formation of inshore sandwaves which are known from previous studies carter 1978 to promote differential erosion of the dune cliffs however longer term changes in shoal geometry lead to shifts in the pattern of convergence and a general uniformity in erosion rates it is surmised that the gradual development of the ebb shoal and its consequential role in local wave refraction may have been a factor in the cessation of holocene beach ridge formation

overwash threshold for gravel barriers abstract this paper uses results obtained from the large scale bardex experiments undertaken in the delta flume to investigate the morphological response of a prototype gravel barrier to wave and tidal forcing during overwash conditions gravel barrier behaviour depends upon a number of factors such as sediment properties porosity permeability grainsize geological setting and wave climate since overwash processes are known to control short term gravel barrier dynamics and long term barrier migration the development of a robust quantitative method to define the critical conditions leading to gravel barrier overwashing is important both for scientific and practical management purposes it is known that when wave runup exceeds the barrier crest elevation three outcomes are possible 1 insignificant morphological change when wave runup just overtops the barrier crest and flow velocities are very weak 2 overtopping resulting in accretion on the barrier crest region and barrier stabilisation and 3 overwashing resulting in erosion lowering of the crest region and ultimately to barrier inundation this study provides an insight into the critical conditions that distinguish these two possible outcomes and to the different mechanisms that provide the required positive and negative feedbacks to the sediment dynamics in order to define the overwash threshold condition and to predict the morphological outcome of particular overwash events use is made here of the overwash potential op defined as the difference between the wave runup and the barrier crest elevation to make effective use of op it is necessary to identify a reliable runup predictor following tests using 12 runup equations the stockdon et al stockdon h f holman r a howd p a sallenger a h 2006 empirical parameterization of setup swash and runup coast eng 53 573 588 approach has been identified as the best predictor of runup conditions necessary to generate positive values of op with overtopping and overwashing predicted to occur for average op values of 0 2 m and 0 5 m respectively the use of op values provides a practical means by which to identify potential coastal hazards associated with gravel barrier overwash processes and is considered to have a range of practical coastal management applications

characterization of heterogeneous near surface materials by joint 2d inversion of dc resistivity and seismic data 1 we have developed a robust 2d joint inversion scheme incorporating the new concept of cross gradients of electrical resistivity and seismic velocity as constraints so as to investigate more precisely the resistivity velocity relationships in complex near surface environments the results of joint inversion of dc resistivity and seismic traveltime data from collocated experiments suggest that one can distinguish between different types or facies of unconsolidated and consolidated materials refining a previously proposed resistivity velocity interrelationship derived from separate inversions of the respective data sets a consistent interpretive structural model can be obtained from the joint inversion models

application of a new 2d time domain full waveform inversion scheme to crosshole radar data crosshole radar tomography is a useful tool in diverse investigations in geology hydrogeology and engineering conventional tomograms provided by standard ray based techniques have limited resolution primarily because only a fraction of the information contained in the radar data i e thefirst arrivaltimesandmaximumfirst cycleamplitudesis included in the inversion to increase the resolution of radar tomograms wehavedevelopedaversatilefull waveforminversion scheme that is based on a finite difference time domain solution of maxwell s equations this scheme largely accountsforthe3dnatureofradar wavepropagationandincludes an efficient method for extracting the source wavelet from the radar data after demonstrating the potential of the newschemeontworealisticsyntheticdatasets weapplyitto two crosshole field data sets acquired in very different geologic hydrogeologic environments these are the first applications of full waveform tomography to observed crosshole radar data the resolution of all full waveform tomograms is showntobemarkedlysuperiortothatoftheassociatedraytomograms small subsurface features a fraction of the dominant radar wavelength and boundaries between distinct geological hydrological units are sharply imaged in the fullwaveformtomograms

boulder dynamics on an atlantic facing rock coastline northwest ireland abstract the rock coast of northwest ireland comprises steep cliffed headlands and more open coastal sections where bedrock shore platforms are developed many shore platforms are overlain by boulders the locations on the platform from which boulders are derived are marked by holes of fresh and unweathered rock surfaces that are not or are poorly covered by lichen these areas of boulder detachment are termed sockets this paper examines the mapped distributions and physical properties of boulders sockets and shore platform context of an atlantic facing granite shore in county donegal northwest ireland results from schmidt hammer rebound tests show statistically significant differences in rebound values between areas inside and outside of sockets and between sockets and boulders based on their distributions and physical properties relationships between sockets and boulders are explored we calculate that sockets are formed rapidly by winter storms but are also rapidly weathered over c 5 years becoming indistinguishable from the surrounding bedrock platform we argue that in contrast to some studies boulders here were formed during recent winter storms episodically during the last 150 200 years rather than by more ancient waves or by tsunamis however a significant proportion of boulders c 20 are morphometrically dissimilar to sockets we argue that these were formed by infrequent and unusually powerful waves that stripped whole bedrock sheets off the platform surface and which detached boulders from the lower shoreface

stochastic modeling of seafloor morphology inversion of sea beam data for second order statistics at scale lengths less than 100 km or so statistical descriptions of seafloor morphology can be usefully employed to characterize ridge crest processes off ridge tectonics and vulcanism sedimentation and postdepositional transport we seek to develop methods for the estimation of seafloor statistics that take into account the finite precision resolution and sampling obtained by actual echo sounding systems in this initial paper we restrict our attention to the problem of recovering second order statistics from data sets collected by multibeam devices such as sea beam the seafloor is modeled as a stationary zero mean gaussian random field completely specified by its two point covariance function we introduce an anisotropic two point covariance function that has five free parameters describing the amplitude orientation characteristic wave numbers and hausdorff fractal dimension of seafloor topography we formulate the general forward problem relating this model to the statistics of an ideal multibeam echo sounder in particular the along track autocovariance functions of individual beams and the cross covariance functions between beams of arbitrary separation using these second moments as data functionals we then pose the inverse problem of estimating the seafloor parameters from realistic noisy data sets with finite sampling and beamwidth and we solve this inverse problem by an iterative linearized least squares method the inversion method is applied to sea beam transit data from both the pacific and atlantic oceans sea beam system noise stands out as a sharp spike on the along track autocovariance function and can be modeled as a white noise process whose amplitude generally increases with beam angle the five parameters in our second order model can be estimated from the inversion of data sets comprising 100 200 km of track length in general the cross track wave number is the most poorly determined although uncertainties in the assumed sea beam response may bias the values of the fractal dimension using the assumed beamwidth the measured noise values and the seafloor parameters recovered from the inversion we generate sea beam synthetics whose statistical character can be directly compared with raw sea beam data for most of the track segments we have processed thus far the synthetics are similar to the data in the case of one atlantic profile however the comparison clearly indicates the necessity of incorporating higher order statistics the space domain procedures described in this paper can be extended for this purpose

extraordinary boulder transport by storm waves west of ireland winter 2013 2014 and criteria for analysing coastal boulder deposits abstract before and after photos of supratidal coastal boulder deposits cbd in the west of ireland show that storms in the winter of 2013 2014 transported boulders at elevations up to 29 m above high water and at inland distances up to 222 m among the clasts transported are eighteen weighing more than 50 t six of which exceed 100 t the largest boulder moved during those storms weighs a fairly astonishing 620 t the boulders moved in these recent storms provide pinning points for mapping storm wave energies on coasts their topographic positions mark elevations and distances inland reached by wave energies sufficient to dislocate those specific masses taken together the cbd data reveal general relationships that shed light on storm wave hydrodynamics these include a robust correlation inverse exponential between maximum boulder mass transported and emplacement height above high water the greater the elevation the smaller the maximum boulder size with a dependency exponent of about 0 2 times the elevation in metres there is a similar relationship although with a much smaller rate of change exponent 0 02 between boulder mass and distance inland which holds from the shoreline in to about 120 m coastal steepness calculated as the ratio of elevation to inland distance seems to exert the strongest control with an inverse power law relationship between maximum boulder mass and slope ratio the more gentle the topography the larger the moved boulders quantifying cbd dynamics helps us understand the transmission of wave energies inshore during high energy storm events the transported boulders documented here are larger than many of those interpreted to have been moved by tsunami in other locations which means that boulder size alone cannot be used as a criterion for distinguishing between tsunami and storm emplacement of cbd the biggest blocks up to 620 t are new maxima for boulder mass transported by storm waves we predict however that this record will not last long the 2013 2014 storms were strong but not extreme and there are larger boulders in these deposits that didn t move on this occasion bigger storms will surely move larger clasts and clasts at greater distances from the shoreline these measurements and relationships emphasise the extreme power of storm waves impacting exposed coastlines and require us to rethink the upper limits of storm wave energy at coasts

estimating the hydraulic conductivity at the south oyster site from geophysical tomographic data using bayesian techniques based on the normal linear regression model this study explores the use of ground penetrating radar gpr tomographic velocity gpr tomographic attenuation and seismic tomographic velocity for hydraulic conductivity estimation at the south oyster site using a bayesian framework since site specific relations between hydraulic conductivity and geophysical properties are often nonlinear and subject to a large degree of uncertainty such as at this site we developed a normal linear regression model that allows exploring these relationships systematically although the log conductivity displays a small variation s 2 5 0 30 and the geophysical data vary over only a small range results indicate that the geophysical data improve the estimates of the hydraulic conductivity the improvement is the most significant where prior information is limited among the geophysical data gpr and seismic velocity are more useful than gpr attenuation

joint acoustic full waveform inversion of crosshole seismic and ground penetrating radar data in the frequency domain abstractintegrating crosshole ground penetrating radar gpr with seismic methods is an efficient way to reduce the uncertainty and ambiguity of data interpretation in shallow geophysical investigations we have developed a new approach for joint full waveform inversion fwi of crosshole seismic and gpr data in the frequency domain to improve the inversion results of both fwi methods in a joint objective function three geophysical parameters p wave velocity permittivity and conductivity are effectively connected by three weighted cross gradient terms that enforce the structural similarity between parameter models simulation of acoustic seismic and scalar electromagnetic problems is implemented using 2d finite difference frequency domain methods and the inverse problems of seismic fwi and gpr fwi are solved using a matrix free truncated newton algorithm the joint inversion procedure is performed in several hierarchical frequencies and the three parameter models are sequentially inverted at each

mesoscale coastal behavior related to morphological self adjustment high energy events extratropical storms tsunamis and hurricanes sediment supply variability and sea level rise are regarded as major drivers of coastal geomorphic behavior in this paper we document a 170 yr record of cyclic coastal changes that occur independently of such external drivers in a geologically constrained situation with no external sediment input two end member morphological configurations attractors are identified between which the system alternates although neither configuration is stable the system as a whole exhibits century scale equilibrium our findings present a hitherto unreported form of decadal scale self adjustment in a coastal system that has occurred under a stable sea level with a consistent wave and tidal regime

contrasting styles of swell driven coastal erosion examples from kwazulu natal south africa during 2006 2007 the kwazulu natal coast of south africa was exposed to several large swell events ho 3 m near the peak of the lunar nodal cycle causing shoreline recession the largest swell hs 8 5 m struck the coast on the march equinox 18th 20th and generated a strong storm return flow observations made before during and after record dramatic coastal erosion shoreline recession of up to 40 m and substantial property damage this swell event removed the semi continuous nearshore bar system and conditioned the coast such that lesser subsequent swell events accomplished much greater amounts of coastal erosion than expected up to 100 m at certain erosion hotspots because waves reached the coast without significant energy dissipation subsequent bar generation rebuilt the inshore bars within six months the styles of erosion during the march 07 event and other 2007 swells were markedly different lesser swells are focused by headlands and result in megarip development and activation of erosion hotspots the march 07 event still water level was raised equinoctial spring high tide and a storm surge of 0 33 0 45 m to a level that rendered most headlands and erosion hotspots ineffective and resulted in laterally extensive erosion of soft shorelines results record cumulative effects of successive swell events on coastal behaviour that proved to be critical in enabling erosion to proceed at rapid rates after the coast had been initially destabilized unlike hurricanes and tsunamis surges associated with swell events are relatively minor and therefore extensive erosion is linked with high lunar tides there is circumstantial evidence that swell induced erosion follows the broad 18 6 yr lunar nodal tidal cycle when the chances of large swells coinciding with high water levels are increased

definition of storm thresholds for significant morphological change of the sandy beaches along the belgian coastline abstract in this paper a storm threshold for significant morphological change along the belgian coastline is presented using a dataset covering topography bathymetry and hydrodynamic conditions for the period 1983 2007 the main erosive years on the one hand and the most severe storm events on the other hand have been selected the topographic data were processed into erosion and accretion trends corrected for nourished volumes for both the supratidal beach and the dune in total 42 storms were recognised and for each of these storms the maximum water level the storm duration the wave energy and the main wind direction have been determined to link the eroded volumes to the storm events the total erosion of all the affected areas per year i e winter season has been compared with the total wave energy of all the storm events that occurred during the same period based on the five most erosive winter seasons 1984 1987 1990 1994 and 1995 it is concluded that in order to cause a significant morphological impact along major parts of the belgian coastline as a first indication an individual storm should be characterised by the following criteria maximum significant offshore wave height higher than 4 m maximum water level above 5 m taw storm duration longer than 12 h an induced wave energy above 6 5 e 05 j m and wind direction between w and nw although the applied methodology has its limitations due to the wide time spacing of the topographic measurements and the lack of details on beach morphological changes the severest storm periods from the last 25 years clearly left significant marks in the time series of recorded volume evolution therefore the proposed thresholds provide a valuable first estimate of the threshold for significant morphological change along the entire belgian coastline if in the future pre and post storm related beach morphology measurements would be available the above defined thresholds could be refined or even thresholds for different sectors along the belgian coastline could be established taken into account the beach morphology

holocene sea levels last glacial maximum glaciomarine environments and geophysical models in the northern irish sea basin uk newly acquired geological records from the isle of man reveal intercalated intertidal and terrestrial sediments that record a relative sea level rise from ca 3 86 m in the early holocene up to a mid holocene maximum between ca 6 6 and 4 5 cal kyr bp at ca 2 25 m when compared with similar marine records from elsewhere in the northern irish sea basin the sea level data confirm a strong north south trend in glacioisostatic loading but little east to west difference in loading this pattern results from the central northern sectors of the british ice sheet over scotland strongly influencing the glacioisostatic downwarping throughout the northern irish sea basin differential ice thicknesses over the irish sea the lake district and ireland did not cause perturbations of local glacioisostatic signatures the holocene marine data in the central irish sea record a slow termination of global eustatic sea level rise during the early holocene geophysical predictions of relative sea level partially constrained by the holocene rsl observations but extrapolated to the last glacial maximum show the potential for shallow marine conditions in the central irish sea basin and in northeast ireland between ca 21 0 16 0 cal kyr bp however glaciomarine deposits in northeast ireland suggest the model relative sea level predictions are too low and require increased ice loading or a thinner lithosphere to generate extra glacioisostatic depression at the time of deglaciation furthermore predicted deglacial relative sea level for northeast ireland does not match the geological record highlighting complex ice margin ocean interaction during deglaciation on the isle of man where glacioisostatic loading is of a similar magnitude to that across northeast ireland the presence of grounded ice inhibited marine incursion during early deglaciation but the occurrence of glaciolacustrine conditions along the ice margin as it moved northwards supports model predictions that relative sea level fell below present during the late glacial early holocene due to rapid glacioisostatic rebound

the emergence and future of near surface geophysics over the past 30 years geophysical methods have assumed a much more prominent and integral role in many investigations where subsurface features have environmental and engineering importance in fact the field once referred to as environmental and engineering geophysics has broadened to include other applications e g archeology forensics and is now commonly referred to more generally as near surface geophysics it is difficult to precisely define near surface geophysics and the definition will likely depend on whom you ask however we define it as the use of geophysical methods to investigate the zone between the surface and hundreds of meters into the earth s crust applications include but are not limited to potable water management engineered infrastructure and construction site clearance gas storage natural hazard mitigation mining forensics and archaeology although the same physical principles are relevant for any target depth the high degree of near surface heterogeneity ra

soil landscape modelling using fuzzy c means clustering of attribute data derived from a digital elevation model dem this study explores the use of fuzzy c means clustering of attribute data derived from a digital elevation model to represent transition zones in the soil landscape the conventional geographic model used for soil landscape description is not able to properly deal with these fuzzy c means clustering was applied to a hillslope within a small drainage basin in southern spain cluster validity evaluation was based on the coefficient of determination of regressing topsoil clay data on membership grades the resulting clusters occupied spatially contiguous areas we found a high degree of association with measured topsoil clay data r a 2 0 68 for three clusters and a weighting exponent of 2 1 location of the clusters coincided with observable terrain characteristics therefore we concluded that the coefficient of determination of regressing soil sample data on membership grades efficiently supports deciding upon the optimum fuzzy c partition the study confirms that fuzzy c means clustering of terrain attribute data enhances conventional soil landscape modelling as it allows representation of fuzziness inherent to soil landscape units

sediment accumulation in embayments controlled by bathymetric slope and wave energy implications for beach formation and persistence high energy rocky coastlines often feature sandy beaches within headland bound embayments not all such embayments have beaches however and beaches in embayments can be removed by storms and may subsequently reform what dictates the presence or absence of an embayed beach and its resilience to storms in this paper we explore the effect of offshore slope and wind conditions on nearshore sediment transport within idealised embayments to give insight into nearshore sediment supplies we use numerical simulations to show that sand can accumulate near shore if the offshore slope is 0 025 m m but only under persistent calm conditions our modelling also suggests that if sediment in an embayment with an offshore gradient steeper than 0 025 m m is removed during a period of persistent stormy conditions it will be unlikely to return in sub decadal timescales in contrast sediment located in embayments with shallower gradients can reform swiftly in both calm and stormy conditions our findings have wide implications for contemporary coastal engineering in the face of future global climate change but also for quaternary environmental reconstruction our simple method to predict beach stability based on slope can be used to interpret differing responses of embayments to periods of changing coastal storminess such as the medieval climate anomaly little ice age mca lia transition

refraction tomography over a buried waste disposal site determining the depth and geometry of a landfill s lower boundary is a difficult task potential field methods generally lack the necessary depth resolution and seismic reflection data are usually contaminated by source generated noise in the time range of interest 50 ms to address this problem we have developed a surface 2 d tomographic refraction scheme that is based on a fast finite difference eikonal solver and an inversion method that incorporates appropriate damping and smoothing constraints this new scheme has been applied to a first arrival traveltime data set collected across adjacent landfills in northern switzerland high quality seismic data were collected along five profiles that crossed the landfills and two that sampled undisturbed natural sediments seismic waves generated from multiple shots were recorded on large numbers of closely spaced receivers during quiet evening periods reliability of the resultant velocity tomograms was estimated on the basis of 1 ray diagrams 2 plot

hydrogeological characterization of the south oyster bacterial transport site using geophysical data a multidisciplinary research team has conducted a field scale bacterial transport study within an uncontaminated sandy pleistocene aquifer near oyster virginia the overall goal of the project was to evaluate the importance of heterogeneities in controlling the field scale transport of bacteria that are injected into the ground for remediation purposes geochemical hydrological geological and geophysical data were collected to characterize the site prior to conducting chemical and bacterial injection experiments in this paper we focus on results of a hydrogeological characterization effort using geophysical data collected across a range of spatial scales the geophysical data employed include surface ground penetrating radar radar cross hole tomography seismic cross hole tomography cone penetrometer and borehole electromagnetic flowmeter these data were used to interpret the subregional and local stratigraphy to provide high resolution hydraulic conductivity estimates and to provide information about the log conductivity spatial correlation function the information from geophysical data was used to guide and assist the field operations and to constrain the numerical bacterial transport model although more field work of this nature is necessary to validate the usefulness and cost effectiveness of including geophysical data in the characterization effort qualitative and quantitative comparisons between tomographically obtained flow and transport parameter estimates with hydraulic well bore and bromide breakthrough measurements suggest that geophysical data can provide valuable high resolution information this information traditionally only partially obtainable by performing extensive and intrusive well bore sampling may help to reduce the ambiguity associated with hydrogeological heterogeneity that is often encountered when interpreting field scale bacterial transport data

integrated data analysis for mineral exploration a case study of clustering satellite imagery airborne gamma ray and regional geochemical data suites abstractpartitioning cluster algorithms have proven to be powerful tools for data driven integration of large geoscientific databases we used fuzzy gustafson kessel cluster analysis to integrate landsat imagery airborne radiometric and regional geochemical data to aid in the interpretation of a multimethod database the survey area extends over 3700 km2 and is located in the northern cape province south africa we carefully selected five variables for cluster analysis to avoid the clustering results being dominated by spatially high correlated data sets that were present in our database unlike other more popular cluster algorithms such as k means or fuzzy c means the gustafson kessel algorithm requires no preclustering data processing such as scaling or adjustment of histographic data distributions the outcome of cluster analysis was a classified map that delineates prominent near to surface structures to add value to the classified map we compared the detected structures to mapped geology an

delineation of hydrochemical facies distribution in a regional groundwater system by means of fuzzy c means clustering 1 in this paper classification of a large hydrochemical data set more than 600 water samples and 11 hydrochemical variables from southeastern california by fuzzy c means fcm and hierarchical cluster analysis hca clustering techniques is performed and its application to hydrochemical facies delineation is discussed results from both fcm and hca clustering produced cluster centers prototypes that can be used to identify the physical and chemical processes creating the variations in the water chemistries there are several advantages to fcm and it is concluded that fcm as an exploratory data analysis technique is potentially useful in establishing hydrochemical facies distribution and may provide a better tool than hca for clustering large data sets when overlapping or continuous clusters exist index terms 1806 hydrology chemistry of fresh water 1829 hydrology groundwater hydrology 1831 hydrology groundwater quality 1871 hydrology surface water quality keywords clustering techniques fuzzy logic fuzzy c means hydrochemical facies hydrochemistry inverse modeling

establishing storm thresholds for the spanish gulf of cadiz coast abstract in this study critical thresholds are defined for storm impacts along the spanish coast of the gulf of cadiz the thresholds correspond to the minimum wave and tide conditions necessary to produce significant morphological changes on beaches and dunes and or damage on coastal infrastructure or human occupation threshold definition was performed by computing theoretical sea level variations during storms and comparing them with the topography of the study area and the location of infrastructure at a local level specifically the elevations of the berm the dune foot and the entrance of existing washovers were selected as threshold parameters the total sea level variation generated by a storm event was estimated as the sum of the tidal level the wind induced setup the barometric setup and the wave associated sea level variation wave setup and runup assuming a minimum interaction between the different processes these components were calculated on the basis of parameterisations for significant wave height hs obtained for the oceanographic and environmental conditions of the gulf of cadiz for this purpose real data and reanalysis time series hipocas project were used validation of the obtained results was performed for a range of coastal settings over the study area the obtained thresholds for beach morphological changes in spring tide conditions range between a significant wave height of 1 5 m and 3 7 m depending on beach characteristics while for dune foot erosion are around 3 3 to 3 7 m and for damage to infrastructure around 7 2 m in case of neap tide conditions these values are increased on average by 50 over the areas with large tidal range furthermore records of real damage in coastal infrastructure caused by storms were collected at a regional level from newspapers and other bibliographic sources and compared with the hydrodynamic conditions that caused the damage these were extracted from the hindcast database of the hipocas project including parameters such as storm duration mean and maximum wave height and wave direction results show that the duration of the storm is not critical in determining the occurrence of coastal damage in the regional study area this way the threshold would be defined as a duration 30 h with moderate average wave height 3 3 m and high maximum wave height 4 1 m approaching from the 3rd and 4th quadrants during mean or spring tide situation the calculated thresholds constitute snapshots of risk conditions within a certain time framework beach and nearshore zones are extremely dynamic and also the characteristics of occupation on the coast change over time so critical storm thresholds will change accordingly and therefore will need to be updated

integration of diverse physical property models subsurface zonation and petrophysical parameter estimation based on fuzzy c means cluster analyses inversions of an individual geophysical data set can be highly nonunique and it is generally difficult to determine petrophysical parameters from geophysical data we show that both issues can be addressed by adopting a statistical multiparameter approach that requires the acquisition processing and separate inversion of two or more types of geophysical data to combine information contained in the physical property models that result from inverting the individual data sets and to estimate the spatial distribution of petrophysical parameters in regions where they are known at only a few locations we demonstrate the potential of the fuzzy c means fcm clustering technique after testing this new approach on synthetic data we apply it to limited crosshole georadar crosshole seismic gamma log and slug test data acquired within a shallow alluvial aquifer the derived multiparameter model effectively outlines the major sedimentary units observed in numerous boreholes and provides plausible estimates

velocity variations and water content estimated from multi offset ground penetrating radar the common midpoint cmp processing technique has been shown to be effective in improving the results of ground penetrating radar gpr profiling when radar data are collected with the cmp multioffset geometry stacking increases the signal to noise ratio of subsurface radar reflections and results in an improved subsurface image an important aspect of cmp processing is normal moveout velocity analysis our objectives are to show the effect of multiple velocity analyses on the stacked radar image and particularly to demonstrate that this velocity information can also be used to determine subsurface water content most gpr surveys are very limited in spatial extent and assume that within the survey range radar velocity structure in the shallow subsurface can be adequately approximated by a single velocity function in data processing in this study we show that variation in radar velocity can be quite significant and that the stacked profile improves as the number of velocity analysis locations is increased interval velocities can be calculated from the normal moveout velocities derived in the cmp velocity analysis with some reasonable assumptions about subsurface conditions necessary for radar propagation interval velocity can be converted to an estimate of volumetric water content therefore by collecting gpr data in the multioffset cmp geometry not only is the radar profile improved but it also allows for an interpretation of subsurface variation in water content we show the application of these techniques to multioffset gpr data from the chalk river test area operated by atomic energy of canada limited

the extreme 2013 2014 winter storms beach recovery along the southwest coast of england abstract sand and gravel beaches naturally act as a coastal buffer absorbing wave energy and dynamically adapting to the seasonal and long term wave climate significant shifts in nearshore morphology can occur during extreme wave events which can have a significant impact on coastal vulnerability during the winter of 2013 14 the atlantic coast of europe received an unprecedented sequence of very energetic wave conditions 8 week mean offshore h s 4 4 m these events caused extensive physical beach and dune erosion and socio economic flooding damage to infrastructure impacts throughout the west coast of europe many monitored sites in the uk and france were in their most eroded state since morphological records began 5 10 years we consider the geomorphological significance of the storm response at 38 natural beaches in the southwest of england ranging from semi sheltered reflective gravel barriers to ultra dissipative exposed sand beaches with dunes the extent and patterns of post storm recovery are examined in detail at three beaches with characteristic storm response behaviours exposed sandy beaches were dominated by cross shore transport processes leading to significant loss of sediment offshore from the intertidal zone 200 m 3 m exposed gravel beaches were dominated by overwash with significant loss landward and semi sheltered sites exposed to more oblique wave forcing were dominated by a rotational response due to alongshore sediment redistribution due to these contrasting responses mechanisms and timescales for beach recovery displayed strong inter site and intra site variations in offshore and rotational cases the recovery processes were multi annual comprising seasonal to decadal signals and were intrinsically linked to the storm response mechanisms while permanent losses occurred when overwash dominated we show that post storm recovery does not necessarily occur during calm periods and that in many cases high energy wave events appear to be essential for recovery of sediment offshore and counter rotation our results highlight the significance of dominant climatic oscillations multi annual storm sequencing storm tracks and resultant variations in wave angle in controlling the impact that extreme wave events have on contrasting sand gravel beaches in exposed sheltered locations