luminescence dating of sediments from buctouche spit new brunswick in this paper we describe our efforts to determine the formation chronology of a sequence of dunes on buctouche spit a holocene deposit on the northeast coast of new brunswick optical dating using infrared stimulation of k feldspar grains yielded ages ranging from 5 30 a for an embryo dune to 765 45 a for the oldest dune thermoluminescence ages although less precise support the recent formation of the dunes the ages exhibit the expected sedation from youngest to oldest and are consistent with historical evidence coupled with an assumed constant sediment aggradation rate the age resolution obtained was very good and we conclude that the optical dating method used here shows great promise

reconstruction of holocene foreland progradation using optically stimulated luminescence osl dating an example from dungeness uk roberts helen plater a j 2007 reconstruction of holocene foreland progradation using optically stimulated luminescence osl dating an example from dungeness uk the holocene 17 4 pp 495 505 rae2008

deriving mechanisms and thresholds for cliff retreat in soft rock cliffs under changing climates rapidly retreating cliffs of the suffolk coast uk abstract understanding changing thresholds and mechanisms for retreat in soft rock cliffs is important under changing climates this can be achieved through combining detailed field observation long term process and morphological monitoring and numerical modelling the cliffs of the suffolk coast southern north sea have exhibited long term 1883 2010 recession rates of 3 5 m a 1 rising to 4 7 m a 1 in the period 1993 2010 annual to biannual ground survey data and the application of gis techniques to digitised records of changing shoreline position from historic maps and aerial photography reveal considerable decadal scale variations in cliff recession within which are nested inter annual fluctuations in rates of retreat archival datasets on significant periods of onshore winds and their interaction with high water levels including the incidence of storm surges and rainstorm events are used to determine thresholds for cliff base erosion and its propagation upwards through the cliff profile in addition the geo slope dynamic coupled hydrology stability model is used to establish thresholds for cliff face failures driven by variations in rainfall inputs retreat mechanisms are complex governed by cliff geology both as a primary control on suction loss and through its interaction with basal marine conditions the study allows a general model of cliff retreat for soft rock cliffs to be put forward whereby a resistant basal platform is overlain by more erodible weakly and moderately cemented sands and gravels in this model the varying balance between marine and terrestrial forcing factors are reflected in low 7 m a 1 modes of cliff retreat

a methodology for the study of the relation between coastal cliff erosion and the mechanical strength of soils and rock masses abstract a methodology is proposed to make approximate estimates of the destructive force of waves at the bottoms of cliffs where no accurate bathymetric data are available by means of correlation between the erosion rate of rocky coasts and the mechanical strength of soils and rock masses the correlation used makes it possible to obtain a linear semi logarithmic expression between the long term average erosion rate from an engineering standpoint of coasts consisting of different lithologies wave energy and the uniaxial compressive strength of soils and rock masses forming the cliffs the uniaxial compressive strength of soils consisting of landslide debris was measured using a pocket penetrometer and the rock mass index rmi method was used for rock masses these methods were chosen after critical analysis of the methodologies currently available the proposed approach was tested in the cilento area of southern italy and in particular along a 6 km stretch of coast typified by rock masses and landslide debris that are particularly susceptible to erosion this coastline is exposed to south westerly waves which in deep water reach significant heights between 1 and 3 m and significant wave periods between 4 and 7 s estimates of the coastal erosion rates were made by studying the variations especially in restricted headland areas occurring over two time spans 30 and 45 years respectively by comparing topographic maps and aerial photographs taken at different times these comparisons give approximate indications of retreats of 15 m over the time span of 30 years average erosion rate of 0 5 m year 1 and of 35 m over the time span of 45 years average erosion rate of ca 0 8 m year 1 these data do have a local significance but clearly show how quick these processes sometimes are lastly the study of a notch incised by wave action on a concrete sea wall built to protect a terrace made it possible to quantify the impact of erosion on concrete it was possible to obtain rmi values through field observations furthermore it was possible to obtain the constants of the hoek and brown failure criterion using rmi on the basis of rmi values the rock masses studied were defined as moderately strong to strong and according to the hoek and brown criterion as poor to fair a semilogarithmic linear relation was found between the strength of landslide debris rock masses and concrete as well as their respective long term erosion consequently a rough estimate of the destructive force of waves ca 24 mpa was calculated this value is given by the product of the mean value of their hydraulic pressure for a non dimensional constant which in turn takes into account the sandy pebbly beach sediment at the foot of the cliffs that acts as an abrasive on the rock mass

new perspectives on coastal landscape reconstruction during the late quaternary a test case from central israel the stratigraphic architecture of coastal plains is determined by the interactions between local e g fluvial processes and topography regional e g climate and global e g sea level forcing factors primarily during the late quaternary period detailed stratigraphic and sedimentological analyses of boreholes cored between coastal ridges in the lowlands coupled with optically stimulated luminescence osl dating and integrated with existing onshore and offshore databases has enabled a 4 d reconstruction of the evolution of the coast of israel during the last glacial interglacial cycle this model revealed that nilotic sourced littoral sand intermittently transported inland by wind has either been lithified into aeolianite or pedogenized into orange brown palaeosol from about 100 ka to 8 ka dark silty clay wetlands were deposited between the aeolian coastal ridges adjacent to streams which cut the israeli coastal plain and flow westward from the last glacial maximum until the onset of the holocene these units are topped by beach and aeolian quartz sand dated to 6 6 0 1 ka diachronous thicknesses and lithological dissimilarities were identified between the sections studied and previous reports on adjacent coastal aeolianite ridges streams were found to be a dominant control on the stratigraphical composition and related facies architecture due to fluvial induced erosion consequently the relief variations between the lowland and cliff controlled aeolian pedogenesis as well as alluvial processes from about 80 to 5 ka climate mainly influenced by precipitation and dust input induced pedogenic processes while sea level lowstand during the last glacial maximum is shown to have hindered sediment deposition in the shallow offshore which in turn affected aeolian transport reducing sediment accumulation on the palaeo coastal plain the palaeoenvironmental model presented in the current study serves as an example for understanding the evolution of similar low latitude siliciclastic rich low gradient shelf coastal areas during the last glacial interglacial cycle furthermore it demonstrates the influence of local to global forcing factors on these environments

sea cliff erosion as a function of beach changes and extreme wave runup during the 1997 1998 el nino abstract over time scales of hundreds to thousands of years the net longshore sand transport direction along the central california coast has been driven to the south by north pacific winter swell in contrast during the el nino winter of 1997 1998 comparisons of before and after airborne lidar surveys showed sand was transported from south to north and accumulated on the south sides of resistant headlands bordering pocket beaches this resulted in significant beach erosion at the south ends of pocket beaches and deposition in the north ends coincident with the south to north redistribution of sand shoreline morphology became prominently cuspate with longshore wavelengths of 400 700 m the width and elevation of beaches were least where maximum shoreline erosion occurred preferentially exposing cliffs to wave attack the resulting erosional hotspots typically were located in the embayments of giant cusps in the southern end of the pocket beaches the observed magnitude of sea cliff retreat which reached 14 m varied with the number of hours that extreme wave runup exceeded certain thresholds representing the protective capacity of the beach during the el nino winter a threshold representing the width of the beach performed better than a threshold representing the elevation of the beach the magnitude of cliff erosion can be scaled using a simple model based on the cross shore distance that extreme wave runup exceeded the pre winter cliff position cliff erosion appears to be a balance between terrestrial mass wasting processes which tend to decrease the cliff slope and wave attack which removes debris and erodes the cliff base increasing the cliff slope

modelling the processes of cliff top erosion and deposition under extreme storm waves at exposed sites on the deep water coasts of the british isles cliff top storm deposits ctsds occur on cliffs at a variety of elevations above sea level and may occasionally reach up to 50 m above sea level time series field mapping of ctsds has demonstrated their formation over the historical period and their continued modification during major past storms this paper seeks to clarify the morphogenetic context of ctsds model the wave conditions and forces encountered at the cliff face and cliff top platform and propose mechanisms to link wave processes to cliff face quarrying and landwards cliff top transport of quarried blocks to deposition zones at the rear of the cliff top platform we report on wave tank experiments using scaled cliff and wave conditions from a cliff in the shetland islands to focus on three situations incident waves lower than the cliff edge height at the same height as the cliff edge height and higher than the cliff edge height the modelling suggests that steep waves of 10 m and above impacting on a 15 m high cliff will result in impact pressures sufficient to promote crack propagation block detachment and lifting of large blocks large but not necessarily steep waves of the same height as the cliff edge produce sufficient impact pressures and water flow over the cliff edge and platform to entrain blocks transport and deposit them on the cliff top where cliff top height is below wave crest elevation green water bore flow occurs sufficient to force rotation or lifting of blocks out of cliff top and cliff top platform sockets high flow velocities rapidly accelerate and transport blocks inland until the flow attenuation results in deposition of blocks at the limit of run up the model results provide a good explanatory framework to account for the quarrying of the upper part of the cliff face and cliff top platform under storm wave conditions and provide an insight into the exceptional velocities experienced over the cliff top platform under bore flow conditions the modelling results show that extreme storm waves are capable of quarrying transporting and depositing large blocks at altitude and significant distances inland and so present serious questions about the use of such deposits as diagnostic of palaeo tsunami

late pleistocene coastal evolution of san giovanni di sinis west sardinia western mediterranean abstract the upper pleistocene succession of coastal deposits outcropping at san giovanni di sinis west sardinia has been studied since the 1960s however the absence of consistent radiometric ages has allowed the production of competing stratigraphic subdivisions of these deposits with different isotopic stage ois mis attributions the succession is composed of sandy to gravelly shallow marine coastal aeolian and alluvial fan plain deposits facies analysis and log correlations show the presence of three unconformities t1 t2 t3 always overlain by shallow marine deposits cutting through the substrate alluvial fan or aeolian sediments we have collected three samples for optically stimulated luminescence osl dating at the top of each shallow marine deposit the succession is composed of four unconformity bounded units u1 u2 u3 u4 and the new osl dates indicate the presence of three different sea level highstands the first unit u1 which is composed of shallow marine to aeolian deposits and overlies transgressive surface t1 is related to a marine transgression during ois 7 186 13 ky unit 2 is composed of continental deposits and formed during ois 6 unit 3 represents ois 5 and overlies a transgressive surface t2 more precisely subunit u3a is related to ois 5e 120 10 ky eu tyrrhenian or eemian sensu strictu and is characterized by shallow marine to aeolian deposits developed during both transgressive and highstand phases the following bay deposits of subunit 3b are associated with ois 5c 100 5 ky and record a second transgressive event t3 and highstand phase occurred during the neo tyrrhenian the succession of san giovanni di sinis ends with continental deposits of unit 4 associated to a sea level fall that took place at the beginning of the last glacial phase ois 4

beach ridges and prograded beach deposits as palaeoenvironment records abstract beach ridges are landforms commonly developed on prograded coasts with beach shorelines a sequence of beach ridges coupled with their subsurface deposits can be regarded as a time series of coastal evolution methodological advances in field surveying and chronology applicable to beach ridges have led to detailed palaeoenvironmental reconstructions to be derived from such sequences this paper reconsiders the basic aspects of beach ridges and deposits which need to be properly understood for their comprehensive interpretation in a palaeo environmental context it also reviews case studies in which beach ridge sequences have been used to unveil past sea level history catastrophic events and climate changes proposed formative processes of beach ridges include 1 progradation of sandy beach and berm formations in relation to fairweather waves coupled with aeolian foredune accumulation 2 building of gravel ridges by storm waves 3 welding of longshore bars beach ridge formation through sea level oscillation is thought to be questionable and caution is suggested for this process when undertaking palaeoenvironmental reconstruction beach deposit stratification is known to dip either landwards or seawards but landward dips are uncommon seaward dipping stratification is formed in relation to beachface progradation and is usually dissected in places by erosion surfaces resulting from episodic beach retreat the boundary between the foreshore and the underlying shoreface is well defined only in the case that longshore bars lead to complex bedding structure relative to that of the foreshore reliable chronology of beach ridges can be determined by radiocarbon and optically stimulated luminescence osl dating radiocarbon dating of articulated shells which are considered not to be extensively reworked provides robust results but osl dating is more useful as it enables direct dating of sediment grains it is noted that there are restrictions in chronological resolution and continuity inherent to beach ridge and beach deposits the plan view geomorphic expression of beach ridges typically consists of ridge sets with multi decadal intervals whereas their internal sedimentary structures define shorter time scales records of beach sedimentation and erosion are likely to be reworked by episodic high magnitude beach retreat and the resultant record of the net progradation is likely to be sporadic and discontinuous the height of sandy beach ridges is often variable due to differing degrees of aeolian sand accumulation and they are thus not used as sea level indicators unless purely wave built gravel ridge height is a relatively reliable indicator of sea level but can vary in response to storminess fluctuations subsurface sediment facies boundaries are preferred as sea level indicators and those proposed include boundaries of aeolian beach foreshore shoreface and upper lower shorefaces catastrophic events are expressed in both erosional and depositional records erosion surfaces or scarp imprints revealed in a cross section of beach deposits indicate storm or tsunami events however erosional events are likely to rework previous records of sedimentation and even other erosional events and thus the apparent history decoded from the resultant deposits tends to be biased several attempts for estimating the frequency and intensity of prehistoric cyclones rely on assumed relationships between the level of coarse sand beach ridges and cyclone inundation the formative process of coarse sand ridges remains uncertain and needs to be clarified as it constitutes the fundamental basis of these attempts the growth rates of beach ridge systems are expected to reflect fluctuations in river sediment discharge to the coast and in aeolian sand flux due to onshore winds both of which are affected by climate change assessment of the growth rate is potentially improved by ground penetrating radar survey of subsurface structure and by detailed chronology orientation of beach ridges reflects long term trends in wave direction inferred relationships between beach ridges and cyclic fluctuations of sea level and climate rely on weak assumptions and are not substantiated by rigid chronological evidence and thus remain highly questionable correlation between the inherently decadal signal of beach ridge intervals and possible climate cycles such as sunspot activity is probably coincidental as it lacks causal explanations

identifying the behavioural characteristics of clay cliffs using intensive monitoring and geotechnical numerical modelling abstract coastal monitoring is routinely undertaken to provide an archival record of cliff line movement that can be used in the development and validation of predictive coast retreat and evolution models however coastal monitoring is often purely quantitative in nature and financial necessity requires deployment over extensive coastal sections as a result for local site conditions in particular only limited geomorphological data are available or included during the development of such predictive models this has resulted in many current models incorporating a simplistic or generalised representation of cliff behaviour an approach that progressively loses local credibility when deployed over extensive heterogeneous coastlines this study addresses this situation at a site of extreme coastline retreat holderness uk through the application of intensive monitoring of six representative cliff sections nested within a general geomorphological appraisal of the wider coastline as a whole the data from these surveys have been used to validate a finite difference based geotechnical modelling assessment of clay cliff stability once validated the geotechnical model was used to simulate a range of scenarios that were sufficient to represent the range of topographic hydrogeological geological and littoral conditions exhibited throughout the region our assessment identified that the cliff retreat occurs through the combined influence of direct marine erosion of the cliff with shallow structurally controlled failures or substantial mass failures critically the predisposition to any one of these failure mechanisms arises principally as a result of initial cliff height the results of the numerical modelling have been combined into an empirical slope model that derives the rate of landslide induced retreat that would arise from mass failures under various future scenarios results of this study can be used in the selection and development of retreat models at coastlines of similar physiographic setting to that found at holderness the results represent a key step in linking material deformation properties to the processes of cliff change and the subsequent range of landforms found on clay cliffs as such the results could also be used more generally to illustrate the likely cliff behaviour of other soft rock coastlines

revealing the coastal event history of the andaman islands bay of bengal during the holocene using radiocarbon and osl dating earthquakes that trigger tsunamis are of great geological ecological and socio economic importance the knowledge of the recurrence interval of these events will give information about the hazard for a region coastal sediments on the andaman islands located in the eastern bay of bengal were investigated to find evidence for palaeotsunamis and palaeoearthquakes fieldwork was conducted on red skin island and north cinque island south of south andaman sediment material from event layers was dated by optically stimulated luminescence and radiocarbon dating method the results show evidence possibly for one earthquake at about 1 000 or 3 000 years before the present together with deposits from possible tsunamis and storms the complex pattern of co and post seismic uplift and subsidence of the andaman islands is reflected in the investigated sections and made it possible to reconstruct an event history for the last 3 000 years

statistical analysis of recent mediterranean sea level data abstract the global rate of sea level rise during the 20th century is generally agreed to be 1 2 5 mm year an examination of the four sea level data series available for the mediterranean shows a sea level rise of a similar rate a statistical analysis based on linear regression reveals this trend to be inconsistent over the century the four time series were divided into two different sets the first consists of records prior to 1960 when sea level was rising consistently and the second from 1961 and onward when there was no significant sea level trend dividing these two data sets into shorter time periods by using additional data from 41 tide gauging stations in the mediterranean showed a consistent trend prior to 1960 between 1961 and 1989 the records show no significant trend this can be due to a rise in mean surface atmospheric pressure of 1 74 3 31 hpa during that period rather than an eustatic decrease in the rate of sea level rise from 1990 onward the sea level recorded in most mediterranean tide gauges indicates a rise in sea level at a rate 5 10 times higher than the 20th century mean rate while this trend should be regarded with some caution because of the relatively short data series the trend observed coincides with the increase in global land and marine surface temperatures during the 1990s and it is important to note that no other short sub period in the data sets shows such an extreme trend

testing optically stimulated luminescence dating of sand sized quartz and feldspar from fluvial deposits abstract we apply single aliquot optically stimulated luminescence osl dating to quartz and feldspar rich extracts from fluvial channel deposits of the rhine meuse system in the netherlands the time of deposition of these deposits is tightly constrained by radiocarbon dating or historical sources this allows us to compare osl ages obtained on quartz and infrared osl ir osl ages obtained on potassium rich feldspar with independent ages over the range of 0 3 13 ka we show that the quartz osl ages are in good agreement with the expected age using ir osl dating of feldspar we find a slight age overestimate for the youngest sample whereas for older samples the age is significantly underestimated we also apply osl dating to older fluvial and estuarine channel deposits with limited independent chronological constraints comparison of feldspar ir osl ages with the quartz osl ages up to 200 ka shows a clear trend where the former severely underestimates the latter this trend is similar to that found for the samples with independent age control indicating that the feldspar ir osl ages are erroneously young for the entire age range in the youngest samples incomplete resetting of the ir osl signal prior to deposition probably masks the age underestimation we show that the ir osl age underestimation is partly caused by changes in trapping probability due to preheating correction for this phenomenon improves the ir osl ages slightly but does not provide a complete solution to the discrepancy we suggest that in the light of the problems encountered in the ir osl dating of feldspar quartz is the mineral of choice for osl dating of these deposits however feldspar dating should continue to be investigated because it has potential application to longer time scales

short and long term erosional processes affecting the stability of the mediterranean coastal cliffs of israel abstract the destructive processes affecting the coastal cliffs of israel are seen as time dependent processes acting in two independent zones at the top and bottom of the cliffs at the top of the cliff these processes are classed as short term phenomena that may be seen as seasonal changes or those initiated by man two main phenomena are recognized as multiple sliding at the contact of hamra clay and kurkar sandstone horizons and collapse of an overlying hard calcarenite layer high water content is by far the most significant contributor to instability which is aggravated by excessive watering of gardens near the cliff edge other factors contributing to instability are grain size and lack of cementation at the bottom of the cliff these processes are classed as long term phenomena where several climatic seasons to a number of years may pass between events these processes are mainly dependent on the abrasive action of waves and to a lesser extent on wind stability is dependent on factors such as grain size distribution of particles cross bedding and degree of cementation of the sandstone the factor of safety f for kurkar slopes ranges from f 1 29 1 78 and that of hamra slopes from f 0 59 0 60 recognition of the active processes causing instability in the different parts of the cliffs and the factors controlling them is essential for the design and remedial measures required for controlling the continued destruction of the cliffs

sediment flux dynamics over the shallow 25 m depth shelf of the mediterranean sea along the israeli coast abstract in order to study the dynamics of sediment fluxes at the northern end of the nile littoral cell sediment traps were deployed for one year over the shallow shelf of the mediterranean sea offshore israel the sediment traps replaced monthly were suspended on a mooring line two kilometers offshore of the hadera power station 10 m above a 25 m deep seafloor sea state conditions near the traps were measured by an acoustic doppler profiler that provided the bottom water temperature wave heights and current s velocities and direction the measured sediment fluxes greatly varied between sampling periods with a minimum value of 1 8 g m 2 d 1 in autumn and a maximum value of 83 g m 2 d 1 in winter this variation was mostly effected by wave induced resuspension of sediment a strong correlation r2 0 97 was found between integrated wave heights that exceeded 1 5 m and the measured sediment fluxes based on the sea state conditions and sediment trap data we conclude that the direction of sand transport at the study area was strictly northwards and that almost all of the annual sand transport occurred during several high energy events in the winter fine particles that consisted the majority of the mass flux were absent in the underlying 25 m deep seafloor suggesting that they are very effectively winnowed off beyond the sand strip

decadal scale coastal cliff retreat in southern and central california abstract airborne lidar data collected in 1998 and 2009 2010 were used to measure coastal cliff erosion and retreat between the mexico california border and bodega head california cliff erosion was detected along 44 of the 595 km of shoreline evaluated while the remaining cliffs were relatively stable the mean cliff top retreat rate was 0 12 m yr while mean retreat averaged over the entire cliff face was 0 04 m yr the maximum cliff top and face retreat rates were 4 2 and 3 8 m yr respectively historical 1930s to 1998 and recent retreat rates were significantly inversely correlated for areas with large historical or recent cliff retreat such that locations with elevated historical retreat had low levels of recent retreat and locations with elevated recent retreat were preceded by low rates of historical retreat the strength of this inverse correlation increased with cliff change magnitudes up to r2 of 0 91 for cliff top retreat rates 2 9 m yr mean recent retreat rates were 52 83 lower than mean historical retreat rates although beaches can protect cliffs against wave driven erosion cliffs fronted by beaches retreated 49 more than cliffs without beaches on average unarmored cliff faces retreated 0 05 m yr between 1998 and 2009 2010 about three times faster than artificially armored cliffs alongshore metrics of wave cliff impact precipitation and cliff hardness were generally not well correlated with recent cliff changes a cliff hazard metric is used to detect cliff steepening and areas prone to future cliff top failures

holocene sea level changes along the mediterranean coast of israel based on archaeological observations and numerical model local sea level curves reflect global eustatic changes regional isostatic adjustments of the crust to changing ice and ocean volumes and tectonically controlled crustal movements in this study we evaluate the relative contribution of each of these factors to the holocene sea level curve of the mediterranean coast of israel we use archaeological data as constraints on palaeo sea levels and we then compare the observational limits with isostatic models for sea level change across the region the isostatic model includes the contribution arising from the relative minor increase in ocean volumes for the past 6000 years due to residual melting of ice sheets the effect of the changing shape of the ocean basin the time dependence of shorelines as sealevel changes and the changing surface area occupied by ice sheets differences if significant between the observed and predicted change are interpreted as being of tectonic origin the archaeological observations and the model sea level curve along the mediterranean coast of israel were found to be generally consistent and any discrepancies lie within the uncertainties of both values our model predicted that 8000 years ago sea level at the israel coast was at about 213 5 2 m whereas the archaeological data place it at 216 5 1 m by 7000 bp the predicted level has risen to about 27 1 m consistent with the archaeological evidences according to both observations and predictions sea level was still lower than 2 3t o24 5 m at 6000 bp and remained below its present level until about 3000 2000 bp the comparison between the model sea level curve and the archaeological observations also enable to conclude that the average rate of vertical tectonic movement for the last 8000 years at the carmel coast israel has been less than 0 2 mm year q 2001 elsevier science b v all rights reserved

optical dating of young coastal dunes on a decadal time scale we explore the use of quartz optically stimulated luminescence osl dating for reconstructing coastal evolution on a time scale of decades to a few hundred years samples are taken from the accretionary south west coast of texel a barrier island just offshore of the northern netherlands the ages of dune ridges are known from historical sources an excellent chronology with a decadal accuracy exists for the past 260 years osl ages of less than 10 years on the youngest samples indicate that the osl signal of the quartz grains is very well zeroed prior to deposition and burial osl ages of five samples from a 250 year old dune ridge are indistinguishable and the osl ages on 17 out of 20 samples are in excellent agreement with the well known independent age controls our results highlight the potential of osl dating for high resolution reconstruction of coastal evolution over the past few centuries

effect of the development of notches and tension cracks on instability of limestone coastal cliffs in the ryukyus japan abstract notches cut by waves are currently developing at the base of vertical coastal limestone cliffs in okinawa japan the cliff height varies from 3 0 22 1 m and the maximum notch depth is 8 8 m many rectangular or cubic blocks which appear to have originated from cliff failures are found on platforms in front of the cliffs on the flat top surface of the cliff tension cracks often run parallel to the cliff face the vertical face of the cliffs displays small undulations but no sliding striation suggesting that cliff failures have been caused by toppling rather than by shearing or sliding we use slope stability analysis to determine the critical condition for toppling failure physical and mechanical properties of the cliff material were first obtained from laboratory tests the results indicate that the strength of limestone shows a scale effect such that the strength decreases with increasing size of the test specimens based on this result we estimated the strength of a rock mass corresponding to the size of the coastal cliff cliff stability was then analyzed using a cantilever beam model comparison of the stability analysis and the dimension of fallen blocks indicates that toppling failure is strongly associated with the development of notches and tension cracks

erosional processes in the hard rock coastal cliffs at staithes north yorkshire the processes of change on near vertical coastal cliffs have been quantified using terrestrial photogrammetry and laser scanning the approach allows discrete rockfall geometry to be measured and source located in three dimensions this paper presents the analysis of an inventory of over 100000 discrete rockfalls recorded from the liassic coast at staithes north yorkshire uk where a rock face area of over 16000 m 2 has been monitored over a 20 month period the data obtained on three dimensional scar geometry and source position give an insight into rockfall characteristics from a range of rock types cliff heights and geometries multiple failure mechanisms such as overhang collapse constant spalling fragmentation and large scale coherent rockfalls have been observed and related to rock type controlled processes on the rock face the spatially referenced rockfall scar data are used to assess the influence of environmental controls on variable rock mass properties such as rock type structure and cliff geometry analysis of rockfall magnitude frequency reveals notable similarities between coastal rockfalls and inventories from non coastal environments the resolution of the monitoring data allows quantification of rockfalls down to volumes of 1 25 x 10 4 m 3 to be consistently sampled and measured this complete magnitude frequency relationship suggests that rather than evolving exclusively through isolated sporadic losses coastal cliff geomorphology reflects interconnected processes in which each rockfall is part of a continuum of change to the rock face further detailed assessment of the rock face reveals the control of the pre failure morphology on subsequent failure patterns for example the quantity of rock protrusion from the cliff is positively correlated with subsequent failure volume the continuum of activity and the controls on failure identified within these data suggest that the episodic behaviour of coastal cliffs previously assumed may have been overstated by coarser resolution monitoring data the findings improve our understanding of the evolution of coastal cliffs and highlight areas for further research into both cliff processes and the character of rock slope failures in general

a new chalcolithic era tsunami event identified in the offshore sedimentary record of jisr al zarka israel abstract tsunami field evidence is a critical resource for determining coastal risk however in many cases there is low potential for long term preservation of such deposits on land a growing body of evidence suggests that tsunami deposits can be present in the shallow offshore realm and may present a largely untapped but important worldwide sedimentological reference set for investigating past tsunami events here different proxies for tsunami sediment identification and differentiation granulometry xrd xrf ft ir were used to determine the presence or absence of such deposits in a core collected offshore at jisr al zarka midway between tel aviv and haifa the study aimed to recognize anomalous deposits and test different analytical methods to define their origins five anomalous sedimentological horizons were identified four of which were interpreted as tsunamigenic by comparison to previously identified poorly sorted shell rich tsunamites found nearby in caesarea and contrast to the fine sand nile derived background sediments the remaining anomaly was distinctive but not determined to be tsunamigenic due to a lack of coarse shell in the matrix the oldest tsunamigenic layer coinciding with the chalcholithic cultural period 5 7 ka is the oldest such deposit identified offshore israel to date and the non tsunamigenic anomalous horizon may correspond with a transitional climatic phase 5 5 ka this research reinforces the importance of offshore investigations as a means of improving tsunami catalogues and identifying environment altering events

stability of steep slopes in cemented sands the analysis of steep slope and cliff stability in variably cemented sands poses a significant practical challenge as routine analyses tend to underestimate the actually observed stability of existing slopes the presented research evaluates how the degree of cementation controls the evolution of steep sand slopes and shows that the detailed slope geometry is important in determining the characteristics of the failure mode which in turn guide the selection of an appropriate stability analysis method detailed slope profile cross sections derived from terrestrial lidar surveying of otherwise inaccessible cemented sand cliffs are used to investigate failure modes in weakly cemented unconfined compressive strength ucs30 kpa and moderately cemented 30ucs400 kpa sands and their role in the evolution of the geometry of the slopes the results show that high resolution slope topography such as can be obtained with terrestrial lidar is essential for identifying altogether different failure modes in weakly cemented shear mode and moderately cemented tensile mode sand slopes analyses show that the standard culmann method for steep slopes is inappropriate for modeling the stability of cemented sand slopes since it tends to overpredict expected crest retreat and underestimate failure plane angle instead a simplified analysis using infinite slope assumptions but applied to a slope with finite dimensions subject to changing geometric conditions such as toe erosion and slope steepening is suggested for analysis of weakly cemented sand slopes for moderately cemented sand slopes a limit equilibrium analysis directly comparing the cliff tensile stress and cemented sand tensile strength is shown to reasonably predict failure conditions and timing as a result of either slope steepening or tensile strength loss presumably from wetting in most cases doi 10 1061 ascegt 1943 5606 0000396 ce database subject headings slope stability sand soil type limit equilibrium tensile strength failure modes author keywords slope stability cemented sand limiting equilibrium tensile strength lidar cliffs failure mode

ancient coastal wells of caesarea maritima israel an indicator for relative sea level changes during the last 2000 years abstract during the detailed excavations of ancient caesarea israel east mediterranean 64 coastal water wells have been examined that date from the early roman period with the oldest occurring in the 1st century ad up to the end of the crusader period mid 13th century ad the depths of these coastal water wells establish the position of the ancient water table and therefore the position of sea level for the first century ad up to 1300 ad the connection between the coastal water table and changes in sea level has been established from modern observations in several wells on time scales of days and months and this is used to reconstruct sea level during historical time the results indicate that during the byzantine period sea level at caesarea was higher by about 30 cm than today the late moslem and crusader data shows greater fluctuations but the data sets are also much smaller than for the earlier periods the consistency of the data indicates that the near coastal well data from caesarea provides a reliable indicator of sea level change with an accuracy of about 10 15 cm these results are consistent with observations for earlier periods and with comparisons to model predicted glacio hydro isostatic sea level change indicate that ocean volumes have been constant for much of the past 2000 years the well data is also consistent with an absence of significant vertical tectonic movement of the coast at caesarea over about 2000 years

a predictive model for wave induced cliff erosion with application to pacific coasts of japan a model for predicting the rate of short term bluff recession originally derived from wave tank experiments is tested under field conditions the fundamental equation is dx dt k c ln gh sc where dx dt is the recession rate h is the wave height at the cliff base sc is the compressive strength of the cliff forming material is the density of water g is the acceleration due to gravity c is a nondimensional constant and k is a constant with units of lt 1 the critical wave height to initiate erosion hcrit is given by hcrit sce c g this model is applied to two eroding tertiary cliffs in japan both facing the pacific ocean results show that 1 the larger but rarer waves only cause cliff erosion compared with the smaller but more common waves and 2 the erosion rate at each site is greatly affected by the occurrence frequency of waves higher than hcrit

a new process response coastal recession model of soft rock cliffs abstract the development of cliff erosion predictive models is limited by the complex interactions between environmental processes and material properties over a range of temporal and spatial scales current models incorporate a stochastic representation of cliff behavior based on assumptions regarding the magnitude and frequency of events in a probabilistic framework the new model presented here has been developed to incorporate the behavioral and mechanical characteristics of coastal cliffs which are dominated geologically by overconsolidated clays tills and an associated protective colluvial wedge this model is capable of providing precise and stable responses to some of the inherent uncertainties in cliff recession processes including those caused by different failure mechanisms e g colluvium generation groundwater and erosive tidal cycles material strength is incorporated using the unconfined compressive strength of the material that composes the cliff unlike previous models a calibration parameter is restricted to account for uncertainties linked to marine processes the mechanisms of cliffline retreat have been identified as slump and topple landslides once cliff material has fallen colluvium formation at the cliff foot is incorporated into the model using three different procedures according to the geomechanical characteristics of the debris the model is validated through profile evolution assessment at various locations of coastline retreat on the holderness coast uk higher groundwater content also produces an increase in the number and size of the slope failures the results represent an important step forward in linking material properties to the processes of cliff recession

controls on the size and geometry of landslides insights from discrete element numerical simulations abstract we use numerical two dimensional discrete element method dem to study the controls on the size and geometry of an individual landslide this method allows us to analyze the temporal and spatial evolution of slope failure and landsliding from the intact pre failure slope to the restabilized post failure slope the size of our simulated landslides reflects the amount of disintegrated material available for sliding which is controlled by the peak strength of the slope material and to a lesser degree by the pre failure slope angle the observed size of natural landslides therefore reflects mainly the local natural material strengths we hypothesize that the observed global characteristic landslide size is a result of the limited thickness generally up to a few meters of disintegrated and weathered material that exists on hillslopes poised and ready for sliding the primary controls on the landslide geometry quantified as the ratio of their thickness to length t l prove to be the residual friction angle of the slope material and the original slope angle the t l is observed to be unchanged for a given initial slope angle and independent of the slope material peak strength or the slope height we suggest that the narrow range of observed natural t l is a result of narrow ranges of mechanical properties and initial slope geometries involved in natural slope failure

osl over dispersion a pilot study for the characterisation of extreme events in the shallow marine realm abstract identification of extreme events in the sedimentary record relies on the correct characterisation of the deposit by means of multiple parameters and different diagnostic criteria multiple proxies based on well tested geological biological and chemical analyses have been used to distinguish tsunami layers from other marine extreme events however few proxies distinguish or compare the degree of sedimentary chaos of an event relative to background sediments and between other extreme events in this pilot study the potential of optically stimulated luminescence osl normally used as a dating method is demonstrated and a new potential sedimentological proxy is proposed when analysing in depth the osl signal from single grain measurements to distinguish between underwater deposits derived from marine extreme events embedded in the texturally and compositionally homogeneous shallow shelf archive of the eastern mediterranean newly and previously collected sediment samples from underwater excavations and a sediment core offshore caesarea maritima israel were used in this experiment each sample was associated with either tsunami storm or fair weather normal marine conditions based on multiple proxies in this study single grain over dispersion sg od values and ranges are used as a potentially novel way to quantify the degree of sedimentary chaos thus the degree of scatter of the dose distribution as a function of the efficiency of exposure to sunlight zeroing of the quartz grains entrained during transport and deposition given that turbidity of a fluid should be associated with lower light penetration and higher energy flow with greater sediment density as can occur in tsunamis relative to storms these conditions should be reflected in variations in single grain over dispersion values hence identifying luminescence distribution patterns related to known depositional conditions this quantification is coupled with detailed statistical analysis of the resulting single grain equivalent dose distributions minimally used in osl dating three types of underwater deposits were categorised based on three distribution typologies to which preliminary conservative single grain over dispersion ranges were assigned 60 for tsunami related deposits showing asymmetric distributions with strong positive skewness this new tool provides a means to study offshore extreme marine events without potential dismissal of other identification criteria and proxies based on these results single grain over dispersion osl could be considered as a potential new sedimentological proxy for identification comparison and characterisation of marine derived extreme events in the shallow shelf such as tsunami deposits as it is intrinsic to the sediment grain and the degree of sedimentary chaos of the event itself

temporal and spatial variations in recession rates and sediment release from soft rock cliffs suffolk coast uk high rates of coastal retreat characterise the weakly cemented plio pleistocene rocks and sediments which form much of the cliffed coastline of east anglia southern north sea the accurate establishment of sediment losses from these cliffs has a regional significance as these sediments are important in maintaining beaches and nearshore bank systems and in feeding nearshore sediment transport pathways however the high spatial and temporal variability of cliff failure processes in such materials necessitates fine scale integration of alongshore variations in cliff retreat over a series of well established time periods to accurately define cliffline recession rates and sediment volume inputs to the nearshore system this study applied the dsas digital shoreline analysis system within the gis software package arcmap to digitised georeferenced positions of former shorelines obtained from historic maps and aerial photographs after 1992 for the sections of benacre southwold and dunwich minsmere on the suffolk coast of east anglia uk transects were cast every 10 m alongshore producing very high spatial resolution upon which to assess shoreline retreat over 1000 transects along 11 km of shoreline long term 1883 2008 mean shoreline retreat rates varied between 2 3 3 5 m a 1 benacre southwold and 0 9 m a 1 dunwich minsmere for six cliffed subunits within these larger coastal sections spatial variations in cliffline recession rates for shorter time intervals at ca 20 year intervals within this longer 125 year period were established the combination of recession rates with photogrammetric methods of obtaining cliff top elevation at the same spatial resolution available using aerial photographs and digital terrain models along with cliff sediment composition allowed the calculation of sediment volumetric inputs from cliff retreat in the period 1992 2008 re assessment of the magnitude and location of sediment inputs into the nearshore zone their interaction with regional sediment transport and the growth of inshore bank systems as well as the implications for contemporary and near future coastal management strategies are discussed with reference to this section of the suffolk coast

evolution of a large baltic beach ridge plain neudarss ne germany a continuous record of sea level and wind field variation since the homeric minimum

coastal cliff retreat rates at beit yannay israel in the 20th century research indicates that the aeolianite kurkar cliffs along the israeli mediterranean coastline have continuously retreated eastward during the last few decades there seems to be no dispute among earth scientists regarding the general trend of cliff retreat however the majority of papers displaying cliff retreat rates are based upon comparison of aerial photographs their lack of advanced geometric measurement methods causes a high margin of error public attention is focused upon the beit yannay coastal cliff since private homes are located along the southern section of the cliff crest the current research compares the historic location of the cliff crest edge at beit yannay as observed in a series of aerial photographs taken during the period 1918 2000 quantitative measurement methods included applications of satellite geodesy and digital photogrammetry and mapping research results offer quantitative consecutive and highly accurate data regarding retreat rates over a relatively long period of 82 years it is concluded that 1 annual average cliff retreat rates of the cliff crest is 20 cm year 2 categorization of the study time span reveals periods displaying varying retreat rates such as 27 cm year during 1918 1946 21 cm year during 1946 1973 and 10 cm year during 1973 2000 3 maximum retreat distances of the cliff crest over the study period were found to be approximately 25 m along the northern lowest section of the cliff minimum distances of 11 m were identified at the highest southern section of the cliff 4 the eolianite kurkar cliffs along the israeli mediterranean coast throughout the 20th century have been an important source of sediment contributing approximately 24 10 6 m 3 of sediments to the sediment balance of israeli beaches copyright 2004 john wiley sons ltd

landslides in vibrating sand box what controls types of slope failure and frequency magnitude relations abstract although landslides are a worldwide significant natural hazard their physics is not well understood here landslides were induced in a vibrated box filled with wet practically cohesive sand simulating natural slope failure the questions addressed were a what controls the type of slope failure and b what controls frequency magnitude relations of landslides in the experiments two end member slope failure types were obtained during application of only horizontal acceleration a failure plane rapidly developed followed by a box sized slump in contrast under application of only vertical acceleration mode i fractures formed slowly dissecting the slope into blocks the fractures caused a strength heterogeneity and were followed by block sliding in the vertical shaking experiments a power law size distribution of slide blocks was measured controlled by the fracture distribution the experiments suggest that heterogeneity may be a major control on the size distribution of natural landslide inventories in a homogeneous environment the landslide will have a characteristic size of the whole system in a heterogeneous slope sizes of landslides will reflect the heterogeneity following the above experimental observations our hypothesis is that natural landslides may be divided into two groups small and large the processes controlling their formation are different i the smaller natural landslides occur as slumps within the unconsolidated rather homogeneous sediments typical of the upper few meters close to the surface the size of these slumps is determined by the dependence between failure depth constrained to be the depth of the unconsolidated sediments and area ii in contrast to the homogeneous upper layer rock mass below the unconsolidated sediment is always heterogeneous due to fractures layers and bedding this preexisting heterogeneity is the source of the power law decay observed for the large landslide portion in natural landslide distributions finally in light of these insights in hazard evaluation it is advised to fit a regression line to the power law decay of the large landslide inventory only and consider the characteristic landslide separately

characteristics of sea cliff erosion induced by a strong winter storm in the eastern mediterranean abstract changes in sea cliff morphologies along the 30 km long sharon escarpment segment of israel s weakly cemented mediterranean eolianite cliff line were analyzed to gain quantitative insights into erosion characteristics associated with a high energy winter storm 10 20 year return interval ground based repeat lidar measurements at five sites along the cliff line captured perturbations of cliff stability by basal wave scouring during the storm subsequent post storm gravity driven slope failures in the cliff face above and return of the system to transient stability within several months post storm erosion which amounted to 70 of the total volume of cliff erosion documented resulted in dramatic local effects of up to 8 m of cliff top retreat and yet at the larger scale of the 30 km cliff line examined erosion during the storm and the year that followed affected less than 4 of the cliff length and does not appear to be above the average cliff length annual erosion implied by previously published decadal scale retreat rates along this sea cliff our results do not support a direct association between strong storm events and elevated erosion and retreat at the cliff line scale

applications in geomorphology abstract geomorphology is a pure science with the goal of understanding earth surface processes and landscape evolution and it is also an applied science with the goal of addressing the needs of society with many new high resolution methods of depicting topography and much improved numerical dating geomorphologists are working on problems involving rates of surface processes landscape evolution and applications to areas of concern to society that were impossible to address a few decades ago some of the areas of enquiry where geomorphology has been applied include natural hazards landslides floods earthquakes and tsunamis ecosystem management site anthropology land use planning engineering geology expert witness testimony and hazard reduction assessment and perception how people perceive and respond to potential hazards how their vulnerability can increase their risk and how preparedness and response can be improved depends as much on the social sciences as on physical science

the origin and distribution of soluble salts in the sand seas of northern china article i nfo article history basedonsamples takenfrom four large sandseasof northernchina thispaper first provides basicdataabout the concentrations and chemistries of soluble salts in deserts of northern china and then discusses the origins and parameters triggeringgeographicalvariations the total concentration ofsoluble saltsinthe aeolian sandsof four large sand seas in northern china ranges between 0 14 and 1 32 with the ph of the soluble salts solution mixing ratio of sand and water 1 5 changing between 8 4 and 9 6 confirming alkaline soil conditions in these regions sodiumchloride andbicarbonateare the dominantsaltsoccurringassoluble saltsinthe aeolian deposits of these sand seas the geographical changes of soluble salts concentration display a clear correlation with regionalclimaticparameters i e precipitationandtemperature thedominationofsedimentationofsolublesalts in the aeolian sands deposited via atmospheric processes is discussed which are heavily associated with dry deposition the mean percentages of na and cl derived from dry depositions are estimated to be n90 in both badain jaran and taklamakan deserts

radiocarbon and optically stimulated luminescence dating based chronology of a polycyclic driftsand sequence at weerterbergen se netherlands abstract the chronology of polycyclic driftsand sequences in cultural landscapes has mainly been based on the combination of radiocarbon 14c dating of intercalated organic horizons and pollen analysis this approach however yields indirect age information for the sediment units also as soils are dynamic systems the pedogenetical interpretation of the 14c ages is often quite difficult to improve the results of radiocarbon dating we applied fractionated 14c dating sustained by soil micromorphology and pyrolysis gas chromatography mass spectrometry the results indicate the complexity of the sources and decomposition processes of som and consequently provide information as to why radiocarbon dates are not always reliable for the geochronology of driftsand deposits we then performed an optically stimulated luminescence osl dating study of the driftsand beds in the sequence this approach yields direct sedimentation ages and allows differentiating the instable sand drifting period from the stable soil formation period in each individual cycle of the sequence post depositional mixing of the sands however may upset the reliability of the osl chronology

evolution of late holocene coastal dunes in the cauvery delta region of tamil nadu india widespread occurrences of coastal dunes are observed in the cauvery delta region of tamil nadu in vedaranniyam in the south east coast of india these dunes were studied to establish the chronology of their formation and to understand their evolution using optically stimulated luminescence osl dating in combination with sedimentological studies quartz grain surface morphology using scanning electron microscope grain size and heavy mineral analysis the study shows that on the south east coast of india widespread periodic dune formation reactivation has taken place during the late holocene to very recent times due to a variety of reasons such as climatic variation and land use changes the sand mobility index shows that the dunes in the area have been largely active during the past century in the southern part in nagapattinam region and many of the crests were active in the northern cauvery delta in cuddalore region the angularity and fresh appearance of sand in the inland dunes suggest a short distance of sand transport and a source proximal sand deposition was proposed for the dune formation the study demonstrates the sensitivity of sand dunes on the south east coast of india to varying climatic conditions and changes in regional land use

a chronology of hurricane landfalls at little sippewissett marsh massachusetts usa using optical dating abstract optical dating has been applied to sediments preserved in little sippewissett marsh massachusetts usa which are associated with overwashing of the beach barrier during hurricane strikes on the coast the aims were to determine the hurricane landfall frequency and make comparisons with independent age control and the historical record written sources of hurricane activity along the american east coast are only considered reliable back to the mid 19th century but the sedimentary record is potentially much longer optical dating was applied to quartz grains extracted from thirteen samples within a sediment core from the salt marsh variability in the luminescence characteristics between aliquots was observed and 33 of the measured aliquots were discarded based upon the ratio of the fast component to the medium component the majority of the samples gave normal dose distributions implying homogeneous resetting of the luminescence signal at the time of deposition but three of the samples required application of the minimum age model mam ages ranging between 20 2 and 594 38 years were obtained and are broadly in agreement with independent chronologies thus demonstrating the potential of optical dating in this setting the hurricane record based upon optical dating extends approximately 300 years further back in time than the official national oceanic atmospheric administration noaa record the localised nature of hurricane landfalls means that it will be necessary to collect multiple cores from a number of different sites in order to build up a complete hurricane record for this part of the coast

optical resetting in large drainage basins tests of zeroing assumptions using single aliquot procedures abstract optical resetting of previously accumulated charge populations at the time of transportation and burial of sediments remains a critical assumption in luminescence dating this is particularly the case for fluvial sediments we have tested the extent of bleaching in fluvial environments by applying the single aliquot regeneration sar equivalent dose d e determination technique coupled with tests for partial bleaching in the majority of cases samples collected from a point bar complex on the colorado river texas exhibit evidence of incomplete bleaching use of the minimum sar d e in these cases resulted in estimated residual ages of c 100 300 years in a similar examination of sar d e s for bed load samples collected along the loire river we observe a monotonic decrease in effective equivalent dose d e from values of 14 10 2 and 3 2 mean median and minimum gy at source down to 3 3 3 6 and 1 6 gy in the first kilometre of transportation down to levels of 0 3 0 2 and 0 0 gy for transportation distances exceeding 300 km we observed virtually no effect on the d e in the bed load of the introduction of trunk tributary streams and conclude that the likelihood of resetting of osl in large fluvial systems is somewhat more effective that previously considered when the recycling of sediments down the system are borne in mind

variability of lake michigan water level during the past 1000 years reconstructed through optical dating of a coastal strandplain post nipissing phase strandplains of the great lakes reflect late holocene water levels that are linked to climate variability glacial isostasy and changes in basin hydrology this study examines a strandplain sequence at bailey s harbor door county wisconsin along lake michigan which contains a record of water level variations during the past 1000 years following the separation of the lake michigan huron basin from the lake superior basin vibracores are used to define the current elevation of the foreshore facies in 25 preserved beach ridges optical ages for five individual beach ridges are compared with radiocarbon ages on basal peats from nine swales collected in a previous study the optical chronology yields a ridge formation preservation rate of 30 2 yr ridge similar to that of previous assessments this study further demonstrates the efficacy of optical dating for deciphering late holocene beach ridge sequences providing multidecadal resolution lake level meets or exceeds by at least 0 5 m historic metrics at c ad 1125 1225 the maximum water level after c ad 1225 is comparable with that recorded by the instrumental data there is a noticeable high lake level from c ad 1560 to 1725 dating of additional sites along lake michigan is required to establish local rates of glacio isostatic adjustment identify possible erosion of the outlets and to resolve lake level records for individual lakes following the separation of the upper great lakes currently constrained to have occurred c 2400 to 1200 years ago

emergent characteristics of rockfall inventories captured at a regional scale high resolution rockfall inventories captured at a regional scale are scarce this is partly owing to difficulties in measuring the range of possible rockfall volumes with sufficient accuracy and completeness and at a scale exceeding the influence of localised controls this paucity of data restricts our ability to abstract patterns of erosion identify longterm changes in behaviour and assess how rockfalls respond to changes in rock mass structural and environmental conditions we have addressed this by developing a workflow that is tailored to monitoring rockfalls and the resulting cliff retreat continuously in space in 3d and over large spatial scales 10 4 m we tested our approach by analysing rockfall activity along 20 5 km of coastal cliffs in north yorkshire uk in what we understand to be the first multi temporal detection of rockfalls at a regional scale we show that rockfall magnitude frequency relationships which often underpin predictive models of erosion are highly sensitive to the spatial extent of monitoring variations in rockfall shape with volume also imply a systemic shift in the underlying mechanisms of detachment with scale leading us to question the validity of applying a single probabilistic model to the full range of rockfalls observed here finally our data emphasise the importance of cliff retreat as an episodic process going forwards there will a pressing need to understand and model the erosional response of such coastlines to rising global sea levels as well as projected changes to winds tides wave climates precipitation and storm events the methodologies and data presented here are fundamental to achieving this marking a step change in our ability to understand the competing effects of different processes in determining the magnitude and frequency of rockfall activity and ultimately meaning that we are better placed to investigate relationships between process and form erosion at critical regional scales

luminescence dating of holocene aeolian sand movement thy denmark abstract we report on the application of optically stimulated luminescence dating to an investigation of the frequency of periods of aeolian sand movement and dune formation on the coast of thy holocene aeolian sediments interleaved with peaty palaeosols form some of the most complete successions known in western denmark samples were taken from a coastal exposure and an inland archaeological site dosimetry was based on laboratory gamma spectrometry and quartz luminescence measurements used the single aliquot regenerative dose protocol and 470 30 nm stimulation the sand samples cover an age ranging from about 100 years to 4500 years the youngest dates give us confidence that the material was well bleached at deposition good agreement was obtained with the radiocarbon palaeosol ages we identify three main periods of aeolian sand movement starting at about 4200 2700 and 900 years ago at least during the latter two periods significant aeolian sand movement occurred all three phases of aeolian activity were separated by long periods of stability and soil formation a more recent episode of dune formation restricted to the coast and beginning less than 200 years ago may have been triggered by modern coastal erosion

possible tsunami inundation identified amongst 4 5th century bce archaeological deposits at tel ashkelon israel abstract the eroding coastal sections of ashkelon israel contain exposed sequences of natural and anthropogenic sedimentological deposits some of unknown origin ashkelon an important and long occupied ancient coastal city is directly referred to within written records of past tsunami events yet field studies and archaeological descriptions have not yet corroborated these claims this is not unusual nor unexpected given the amount of anthropogenic and natural disturbance that can erase the sedimentary remains as well as the relatively recent advancements in identifying such deposits a sequence of sediments at the base of an eroding coastal archaeological section shows clear waterborne transport characteristics and was previously interpreted as alluvial however no alluvial sources could be associated to the deposit in this study the sedimentological characteristics of this section were described and analyzed in greater detail to determine their nearest similarity to possible transport mechanism such as storms rivers and tsunamis the deposits contain fining upward sequences rip up clasts imbricated inclusions fine mud layers microfauna foraminifera and broken diagnostic pottery from the 4 5th c bc reconstructions of the coastline at the time of the event place the sampled profile at least 100 m inland from the shoreline at an elevation 2 0 to 2 4 m above sea level river channel features were not identified in the section for this area modern observations of major storms show inundations of

the impact of climatic and seismic events on the short term evolution of seacliffs based on 3 d mapping northern monterey bay california abstract coastal cliff retreat along the central california coast is episodic occurring in response to single large storms or seismic events traditional approaches to the study of long term seacliff retreat utilize historical aerial photography and maps to delineate the landward migration of the top edge of the cliff over periods of tens of years to a century while these methods yield cumulative retreat amounts they provide little or no information on the character of the individual retreat events nor the physical processes of retreat this study addresses the processes of episodic and short term coastal cliff retreat through the analysis of seacliff failure styles and retreat magnitudes the study areas are three 1 km long sections of cliffed coast in northern monterey bay the earliest data set is vertical aerial photography from october 18 1989 taken the day following the magnitude 7 1 loma prieta earthquake more recent photography collected in late january early february and early march of 1998 captured seacliff failure in response to the severe storms associated with the 1997 1998 el nino for each data set high resolution digital photogrammetric techniques are used to identify the top edge of the cliff at each cliff failure location its position failure length and character are documented results suggest that on a regional scale the seacliffs respond to seismic and climatic forcing differently we have found variation in the magnitude of cliff response along the three sections of coast in the study area large scale climatic events such as the 1997 1998 el nino have a greater impact on both the linear extent of seacliff failure and the amount of cliff retreat

pedogenesis and landscape relationships of a holocene age barrier island abstract soil characteristics and pedogenic processes are relatively unstudied on holocene age barrier islands in the mid atlantic region of the united states the objective of this study was to assess how landform stability and hydrologic conditions water availability influenced pedogenesis in barrier island soils ten topographic transects were established on different barrier island landforms i e washover fan back barrier flat barrier flat and dune field which ranged in age from 1 to 228 years the topographic transects spanned drainage conditions ranging from very poorly to excessively drained the primary evidence for pedogenesis across the chronosequence was in the accumulation of organic matter expressed in the formation of a and o horizons pedogenic development was restricted by the young age and weathering resistant nature of the soil parent material the close proximity of the water table to the soil surface was associated with greater organic matter inputs from vegetation and slower decomposition under anaerobic conditions which together led to increased accumulation of organic carbon in lower wetter landscape positions frequency and duration of saturation also impacted subsoil development producing subtle but noticeable color differences between oxidized and reduced horizons

instability investigation of cantilevered seacliffs wave action is a fundamental mechanism in seacliff erosion whereby wave undercutting creates an unstable cantilevered seacliff profile and can lead to large catastrophic cliff failures thus threatening coastal infrastructure this study investigated the instability of two such failures that occurred in solana beach california by combining terrestrial lidar scanning cantilever beam theory and finite element analysis each landslide was detected by evaluating the surface change between subsequent high resolution digital terrain models derived from terrestrial lidar data the dimensions of failed cantilever masses were determined using the surface change measurements and then incorporated into failure stress analysis superimposing stress distributions computed from elastic cantilever beam theory and finite element modeling provided a method to back calculate the maximum developed tensile and shear stresses along each failure plane the results of the stress superposition revealed that the bending stresses caused by the cantilevered load contributed the majority of stress leading to collapse both shear and tensile failure modes were investigated as potential cliff failure mechanisms by using a comparison of the back calculated failure stresses to material strengths found in laboratory testing based on the results of this research the tensile strength of the cliff material was exceeded at both locations thus causing the cliffs to collapse in tension copyright 2008 john wiley sons ltd

late holocene dune migration on the south texas sand sheet abstract there are a wide variety of vegetated eolian depositional landforms associated with the south texas sand sheet attesting to the past dominance of eolian processes mapping identified two sets of parabolic dunes elongating with winds from the southeast and the northwest parabolic dunes elongated by northwesterly winds are older than ca 200 years and may be associated with eolian depositional events ca 2700 and or 2000 years ago the latest dune migration event associated with southeasterly winds occurred ca 200 years ago and at one site is inset into northwesterly extended parabolic dunes this period of dune migration may be coincident with particularly severe drought identified in the tree ring record centered at ad 1790 when the palmer drought severity index was 4 a threshold of dune movement may have occurred ca in the 11th 15th and 20th centuries when there are two or more consecutive years with a palmer drought severity index of

rain waves and short term evolution of composite seacliffs in southern california abstract a four year time series of nine airborne lidar surveys were used to assess the roles of wave attack and rainfall on the erosion of 42 km of southern california seacliffs nine continuous seacliff sections separated by coastal lagoon mouths all show maximum seacliff erosion in the rainiest time period when wave energy was not particularly elevated and in most sections the squared correlations between rainfall and erosion time series exceeded 0 8 although rain and associated subaerial mechanisms such as groundwater seepage triggered most of the observed seacliff failures wave attack accelerated seacliff erosion with erosion rates of cliffs exposed to wave attack five times higher than at adjacent cliffs not exposed to waves the results demonstrate the importance of both waves and rain in the erosion of southern california seacliffs and suggest that the combined influences of marine and subaerial processes accelerate the erosion rate through positive feedbacks

long term cliff retreat and erosion hotspots along the central shores of the monterey bay national marine sanctuary abstract quantification of cliff retreat rates for the southern half of santa cruz county ca usa located within the monterey bay national marine sanctuary using the softcopy geographic information system gis methodology results in average cliff retreat rates of 7 15 cm yr between 1953 and 1994 the coastal dunes at the southern end of santa cruz county migrate seaward and landward through time and display net accretion between 1953 and 1994 which is partially due to development in addition three critically eroding segments of coastline with high average erosion rates ranging from 20 to 63 cm yr are identified as erosion hotspots these locations include opal cliffs depot hill and manresa although cliff retreat is episodic spatially variable at the scale of meters and the factors affecting cliff retreat vary along the santa cruz county coastline there is a compensation between factors affecting retreat such that over the long term the coastline maintains a relatively smooth configuration the softcopy gis methodology significantly reduces errors inherent in the calculation of retreat rates in high relief areas e g erosion rates generated in this study are generally correct to within 10 cm by removing errors due to relief displacement although the resulting root mean squared error for erosion rates is relatively small simple projections of past erosion rates are inadequate to provide predictions of future cliff position improved predictions can be made for individual coastal segments by using a mean erosion rate and the standard deviation as guides to future cliff behavior in combination with an understanding of processes acting along the coastal segments in question this methodology can be applied on any high relief coast where retreat rates can be measured

luminescence chronology of aeolianites from the section at givat olga coastal plain of israel abstract the eastern mediterranean coastal plain of israel is composed mainly of loam sand and gravel of pleistocene to holocene age indicating an alternation of marine coastal and continental environments owing to the complexity of the numerous exposures of aeolianites kurkar and soils hamra in the elongated ridges along the coastal plain it is difficult to set up a reliable stratigraphy a systematic luminescence dating study was carried out on loose sand kurkar and hamra deposits in the coastal plain between netanya and haifa sixteen samples were taken and investigated from the section at givat olga the chronological results show excellent agreement between the infrared optically stimulated luminescence irsl and thermoluminescence tl techniques indicating that the former sand dunes were well bleached prior to deposition the irsl and tl age estimates range from about 75 3 ka for the aeolianites indicating that this kurkar ridge formed during an older period of the last glaciation likely before 50 ka

sediment contribution from israel s coastal cliffs into the nile s littoral cell and its significance to cliff retreat mitigation efforts abstract we quantify the volumetric erosion of israel s actively retreating mediterranean coastal cliffs between 2006 and 2015 with airborne lidar our results reveal annual sand contribution of 45 000 m3 from the coastal cliffs into the nile s littoral cell nlc which amounts to 50 of the annual long shore sand transport previously measured at the northern termination of the nlc accordingly we find that implementation of cliff retreat mitigation engineering efforts planned for israel s coastline can lead to a sand deficit in the nlc that may result in increased beach erosion

luminescence chronology of upper pleistocene and holocene aeolianites from netanya south sharon coastal plain israel abstract the coastal cliff at netanya south in the sharon coastal plain of israel was investigated with luminescence dating methods twenty four samples were taken from the exposed aeolianites and intercalated paleosols the 24 irsl and 24 tl age estimates suggest that the lower 45 m of the section were deposited in oxygen isotope stage 3 the uppermost 7 m of the section are of holocene age and clearly separated by a hiatus of 20 30 ka from the lower part

critical notch depths for failure of coastal limestone cliffs case study at kuro shima island okinawa japan development of a notch at the base of a cliff reduces cliff stability and often induces a collapse pleistocene limestone coastal cliffs of elevation 5 m in kuro shima ryukyu islands have a prominent notch with a depth of 3 4 m at their bases around these coastal cliffs collapses different from previous studies of cliff collapses in the ryukyu islands were found collapses in kuro shima have a horizontal failure surface the horizontal failure surface situated at the height of the failure surface corresponding to the retreat point of the notch is bounded by vertical joints cutting the whole cliff and the reef flat in front of the cliff two types of horizontal failure surface were found triangular and quadrangular the distinction appears to depend on the angle between the vertical joints and the front face of the cliff prior to collapse these cliffs appear to have been separated from the adjacent cliffs by the development of vertical joints consequently a cliff that will collapse can be identified in advance cliff instability is strongly dependent on the development of a notch to study the effect of notch development on cliff collapse the notch depth at which collapse occurs was calculated using stability analysis instability of a cliff increases with notch depth collapse occurs at the horizontal failure surface when the ratio of the notch depth to the seaward length of the cliff is approximately 0 5 0 7 for a triangular failure surface and 0 7 0 9 for a quadrangular failure surface copyright 2010 john wiley sons ltd

comparison of short term seacliff retreat measurement methods in del mar california article i nfo seacliff retreat has been variously characterized as the recession rate of the cliff top of the cliff base and as the bulk recession rate based on volumetric changes of the entire cliff face here these measures of retreat are compared using nine semi annual airborne lidar light detection and ranging surveys of southern california seacliffs changes in the cliff base location where the steeply sloping cliff face intersects the beach include cliff retreat owing to basal erosion but also reflect changes in beach sand level and basal talus deposits averaged over the 2 5 km alongshore study span the cliff base actually prograded seaward about 12 cm during the 4 year study cliff top change was dominated by few relatively large several meters localized retreats cliff face changes that include failures and deposits anywhere on the cliff profile had a relatively small mean magnitude compared to cliff top changes and were more widely distributed alongshore however the similar alongshore averaged cumulative cliff top and net bulk cliff face end point retreat 14 and 19 cm respectively suggest that mean cumulative cliff top retreat can potentially be a viable surrogate for mean net cumulative cliff wide erosion and vice versa over relatively short time periods cliff face erosion occurred repeatedly at some locations confirming the presence of seacliff erosion hot spots during the study period

holocene era submerged notches along the southern levantine coastline punctuated sea level rise abstract the study presented here reports on erosional notches pits and potholes observed at present sea level and submerged at a series of sites along the southern levantine coastline for such submerged features to be formed and preserved there must be a period of relative sea level stagnation followed by drowning this process can occur in response to sea level change tectonic or isostatic offsets the specific coastline hosting these features is not considered tectonically or isostatically affected and therefore for much of the mediterranean is viewed as a eustatic sea level reference point while similar features have been observed elsewhere in the eastern mediterranean confining their ages has been difficult due to the much older ages of the host rocks in many cases encompassing multiple glacial cycles here for the first time they are located in relatively young host rock

processes of coastal bluff erosion in weakly lithified sands pacifica california usa abstract coastal bluff erosion and landsliding are currently the major geomorphic processes sculpting much of the marine terrace dominated coastline of northern california in this study we identify the spatial and temporal processes responsible for erosion and landsliding in an area of weakly lithified sand coastal bluffs located south of san francisco california using the results of a five year observational study consisting of site visits terrestrial lidar scanning and development of empirical failure indices we identify the lithologic and process controls that determine the failure mechanism and mode for coastal bluff retreat in this region and present concise descriptions of each process bluffs composed of weakly cemented sands unconfined compressive strength ucs between 5 and 30 kpa fail principally due to oversteepening by wave action with maximum slope inclinations on the order of 65 at incipient failure periods of significant wave action were identified on the basis of an empirical wave run up equation predicting failure when wave run up exceeds the seasonal average value and the bluff toe elevation the empirical relationship was verified through recorded observations of failures bluffs composed of moderately cemented sands ucs up to 400 kpa fail due to precipitation induced groundwater seepage which leads to tensile strength reduction and fracture an empirical rainfall threshold was also developed to predict failure on the basis of a 48 hour cumulative precipitation index but was found to be dependent on a time delay in groundwater seepage in some cases

late quaternary eolian sand depositional record for southwestern kansas landscape sensitivity to droughts abstract eolian deposits and landforms are ubiquitous in western kansas particularly south of the arkansas river with the presence of a stabilized dune field stratigraphic studies and associated optical dating reveal a complex depositional history for this dune field spanning the late quaternary the oldest eolian deposits from ca 16 to 12 ka completely or partially bury high terraces with ages of ca 16 and 33 ka it is unknown whether these eolian deposits reflect regional aridity and or a change in sediment availability with the transition of the arkansas river from a single channel to a braided system there is pervasive evidence for episodic eolian erosion and deposition ca 9 8 to 6 3 ka generally coincident with loess deposition on upland surfaces olson c g nettleton w d porter d a brasher b r 1997 middle holocene aeolian activity on the high plains of west central kansas holocene 7 3 255 261 and thus it is inferred to reflect regional aridity sites within the dune field show a sequence of eolian sands and weak buried soils reflecting either dune migration or sand sheet accretion at ca 1490 430 380 320 180 and 70 yr ago which correspond well with continental scale droughts in the tree ring record eolian sand in the arkansas river dune field may be derived principally with variability in fluvial activity and in climate during the late pleistocene to the middle holocene with substantial reactivation of eolian systems during decadal scale drought variability in the past 2000 yr

coastal cliff recession the use of probabilistic prediction methods a range of probabilistic methods is introduced for predicting coastal cliff recession which provide a means of demonstrating the potential variability in such predictions they form the basis for risk based land use planning cliff management and engineering decision making examples of probabilistic models are presented for a number of different cliff settings the simulation of recession on eroding cliffs the use of historical records and statistical experiments to model the behaviour of cliffs affected by rare episodic landslide events the adaptation of an event tree approach to assess the probability of failure of protected cliffs taking into account the residual life of the existing defences and the evaluation of the probability of landslide reactivation in areas of pre existing landslide systems these methods are based on a geomorphological assessment of the episodic nature of the recession process together with historical records

chronostratigraphy of aeolianites from the sharon coastal plain of israel abstract the sharon coastal plain in israel is composed mainly of sand dune fields and aeolianite ridges three major sand accumulation periods are documented in the terrestrial record along the cliffs of the sharon coastal plain between 65 to 50 ka from 7 to 5 ka and from 5 to 0 2 ka these seem to correlate with the periods of sapropel formation in the mediterranean sea and so with periods of strongly increased african monsoon activity the accumulation of the stratigraphically oldest aeolianite kurkar unit 5 appears to correlate with sapropel s2 formed about 55 ka bp the uppermost aeolianite calcareous sandstone unit 2 seems to correlate with sapropel s1 formed at about 7 8 4 0 ka bp major soil formations occurred between 35 and 25 ka resulting in a rhodoxeralf soil grumusolic dark brown soil and between 15 and 12 ka resulting in a rhodoxeralf hamra soil at least seven weak weathering horizons regosol type soils are intercalated in the aeolianite of unit v and two regosols are present in the holocene aeolian sand of unit i

examining the effects of ground motion and rock strength on the size of boulders falling from an overhanging cliff the presence of boulders a result of rockfall events at the foot of cliffs testifies for a mass wasting process which is widely observed and is often considered to be triggered by earthquakes here we investigate boulders under an overhanging cliff with an emphasis on the principal factors that control boulder size we used a conceptual cantilever beam model to predict the expected maximum length of the overhanging cliff we then compared these calculated lengths to those of the field observed boulders and the length of the overhanging cliff ledge our observations show that the actual lengths of the boulders and overhanging cliff are much shorter than expected from the model as the study area is located in a tectonically active region we first suggested solving this discrepancy by adding the possible effect of ground motion on the size of a boulder detailed pseudo static and dynamic analysis of the effect of earthquakes on the failure of rock beams shows that boulder length may not significantly be shortened by induced ground motions we therefore conclude that strong earthquakes although triggering rockfalls are not expected to control the resultant size of the boulders found at the base of overhanging cliffs we alternatively suggest that the maximum length of a boulder is strongly controlled by the rock strength we conclude that the maximum boulder size that may fall during an earthquake event can be predicted by calculating the cantilever critical length including the effect of the rock size on its tensile strength this together with the measured rock discontinuities in an overhanging cliff suggests an upper bound for the volume of the falling boulders a crucial factor in assessing rockfall hazards

scilly isles uk optical dating of a possible tsunami deposit from the 1755 lisbon earthquake abstract we present the results of optical dating of quartz from marine and aeolian deposits on st agnes island scilly isles uk the single aliquot regenerative dose protocol was used to estimate the equivalent dose in these samples proposed tsunami laid deposits at big pool provided ages of 230 40 and 380 60 years both are consistent with an expected age of 244 years an osl age of 6 3 years was obtained on a modern sub aqueous beach deposit these results suggest that the osl signal in the tsunami laid quartz was completely reset before deposition and that these sediments can be dated accurately by optical dating techniques sand dunes at bergecooth 250 m south of big pool were also dated using osl these ages indicate phases of aeolian activity at 300 a and 1000 a in the scilly isles

optical dating of dune sand for the study of sea level change a new widely applicable method to obtain well constrained relative sea level records presented here relies on optical dating of inorganic coastal landforms and sediments eighteen optical ages of basal dune sand from a barrier in massachusetts united states indicate that local relative sea level rose 8 m during the past 5 5 k y a sea level curve drawn from these optical ages shows good agreement with independent evidence from salt marsh peat sampled behind the barrier demonstrating the reliability of the method optical dating will be particularly useful in analyzing coastal records that contain too few organic indicators to allow high resolution 14 c based analyses

fluvial geomorphology a perspective on current status and methods fluvial geomorphology seeks to study river landform history understand formative processes and predict changes using a combination of field observation experimental studies and numerical models a resurgence in fluvial geomorphology is taking place fostered for example by its interaction with river engineering and the availability of new analytical methods instrumentation and techniques these have enabled development of new applications in river management landscape restoration hazard studies river history and geoarchaeology this paper presents a perspective on recent advances in fluvial geomorphology and introduces a selection of papers presented during the fluvial geomorphology and palaeohydrology session within the sixth international conference on geomorphology held in zaragoza spain in september 2005

modeling cliff erosion using negative power law scaling of rockfalls we model cliff erosion using an approach based upon the negative power law scaling properties of rockfall magnitude frequency distributions these are derived from an extensive high resolution rockfall inventory for a series of sea cliffs near staithes north yorkshire a comparison between observed volumetric erosion and that produced by the model yields a statistically significant correlation however we note that the temporal resolution of the inventory can have an influence on results our data indicate that monthly inventories are capable of producing magnitude frequency relations that model erosion in good correlation with observed events however for months that experience high magnitude events seasonal inventories are more appropriate furthermore increasing the return period between surveys has the effect of increasing the superimposition of rockfall events thereby reducing the slope of the power law giving an incorrect picture of the scaling properties of rockfalls at this site applying observed variations in the negative power law scaling parameters to a probabilistic simulation model of cliff retreat provides a new means of assessing the most likely erosional scenarios and indicates that the current dataset may not be indicative of long term cliff evolution this may provide a quantitative means of establishing an appropriate time window for characterizing rockfall erosion over decadal time scales