static bay beach concept for scientists and engineers a review abstract headland bay beach hbb is one of the most prominent physiographic features on the oceanic margin of many countries in the world under the influence of a predominant swell its curved periphery in natural environment may reach static equilibrium and remains stable without sediment supply from updrift and or a riverain source within its own embayment coastal scientists and engineers have attempted to develop mathematical expressions to quantify this ideal bay shape since the 1940s as the scenario with depleting sediment supply has become a common reality on many parts of the world coastline in more recent time some coastal engineers have advocated a rational approach to mimicking the static bay shape found in nature in order to mitigate beach erosion as well as for coastal management nowadays many useful applications have emerged since the publication of the parabolic bay shape equation pbse developed for static equilibrium planform sep in late 1980s the advance in modern computer technologies and international collaboration has further facilitated the exchange of knowledge and applications of this static bay beach concept sbbc this paper reviews the progress on the research in hbb made by geographers and geologists since the 1940s together with the involvement of coastal engineers working on shore protection and management from the 1960s aided by software mepbay developed in 2003 for the pbse several practical examples are demonstrated in this paper for the stability verification of natural and man made bay beaches shore protection mitigating downdrift erosion of a harbour design of recreational bay beach as well as for environmental impact assessment limitations on and clarifications for engineering applications based on the sbbc are also discussed in this paper

role of geological inheritance in australian beach morphodynamics the australian coast contains 10 685 beaches which occupy 49 of the 30 000 km coast and average 1 37 km in length their relatively short length is largely due to the presence of bedrock calcarenite and laterite which form boundaries to many of the beaches as well as occurring as rocks reefs and islands along and off the beaches this geological inheritance plays a major role in australian beach systems determining their length and through wave refraction and attenuation influencing beach location shape type morphodynamics and circulation which in turn influence sediment transport and the backing dune and barrier systems this paper uses a database covering every australian beach to review the role of headlands rocks and reefs on australian beaches major effects are the short average beach length reduction in breaker height resulting in lower energy beach types wave refraction resulting in increased beach curvature the presence of topographic rips on moderate and higher energy beaches and megarips during high wave conditions and the interruption of and or trapping of longshore sand transport leading to beach rotation

two magmatic series with island arc affinities within the vourinos ophiolite within the vourinos ophiolite evidence of two magmatic series has been preserved in cognate cumulates and in effusive and hypabyssal rocks which constitute the earlier krapa sequence and the younger asprokambo sequence the asprokambo dyke basic magmas which are poor in incompatible elements and relatively ni and cr rich bear some resemblance to very low ti basalts transitional to boninites found in subduction related arcs or interarc basins krapa series magmas from sills massive and pillow lavas are best equated with low k tholeiites of island arc suites compositions of al and ti poor cpx in lavas from both series are comparable to those in island arc basalts the asprokambo cpx being richer in ca and cr than those from krapa the large volume of cumulates from the krapa sequence displays the following crystallization order ol sp cpx pl opx mt periodic influx of fresh magma batches into the magma chamber occurred mainly during the formation of the lower cumulates wehrlite ol clinopyroxenite and melagabbro the upper cumulates gabbronorite and leucogabbronorite with minor mt bearing gabbronorite crystallized in the upper levels of a magma chamber which became progressively smaller with time in the asprokambo sequence ol sp opx cpx pi and amph are the successively crystallizing phases the ortho to heteradcumulates consist of websterite pl websterite gabbronorite amphibole bearing leuconorite diorite and granophyre in cumulates especially in the lower krapa sequence significant subsolidus reaction was probably induced by the persistence of high geothermal gradients linked to continuous magmatism petrological features indicate that the evolution of the krapa series is more compatible with an intermediate fractional equilibrium crystallization history in an initially open system whereas nearly perfect fractional crystallization in closed system may have occurred in the small asprokambo magma chambers chemical variations in the lavas of both series can be explained in terms of crystallization of the observed cumulates significantly the asprokambo intrusives have igneous mg hornblende and vanadium bearing chromian aluminous titaniferous magnetite crystallization of which is responsible for the calcalkaline evolutionary trend of these rocks major and trace element modelling necessitates a two stage model for the petrogenesis of the vourinos parental melts involving high degree remelting of previously depleted mantle sources favoured by the influx of subduction derived hydrous fluids the primary magmas parental to the krapa and asprokambo series could have been derived respectively by 20 and 30 equilibrium partial fusion of variably depleted lherzolitic sources leaving residua having a harzburgitic to dunitic composition

modeling of 500 year tsunamis for probabilistic design of coastal infrastructure in the pacific northwest abstract this paper describes the development of tsunami scenarios from the national seismic hazard maps for design of coastal infrastructure in the pacific northwest the logic tree of cascadia earthquakes provides four 500 year rupture configurations at moment magnitude 8 8 9 0 and 9 2 for development of probabilistic design criteria a planar fault model describes the rupture configurations and determines the earth surface deformation for tsunami modeling a case study of four bridge sites at siletz bay oregon illustrates the challenges in modeling of tsunamis on the pacific northwest coast a nonlinear shallow water model with a shock capturing scheme describes tsunami propagation across the northeastern pacific as well as barrier beach overtopping bore formation and detailed flow conditions at siletz bay the results show strong correlation with geological evidence from the six paleotsunamis during the last 2800 years the proposed approach allows determination of tsunami loads that are consistent with the seismic loads currently in use for design of buildings and structures

petrogenesis of the zagami meteorite inferences from synchrotron x ray sxrf microprobe and electron microprobe analyses of pyroxenes abstract the zagami meteorite is a shergottite a basalt rich in pigeonite augite and maskelynite glass shocked plagioclase it is one of the snc meteorites which are inferred to have formed on mars major and minor element abundances in pyroxene principally pigeonite from newly available unm samples were determined by electron microprobe abundances of trace elements ni cu zn and ga were obtained by synchrotron x ray sxrf microprobe many pigeonite grains have normally zoned rims and reversely zoned cores so that the most magnesian pigeonite forms rings or annuli in thin section view in three dimensions the most magnesian pigeonite may form tubes or hourglass shapes the cores commonly contain magmatic inclusions other pigeonites have irregular or multiple magnesian regions with magmatic inclusions among and between them abundances of ni and cr in the magnesian zones and cores are partially decoupled from abundances of other compatible mg and incompatible fe ti elements the textures chemical zoning and element decouplings in the pigeonites are consistent with igneous crystal growth at moderate cooling rates not isothermally or near equilibrium from element partitioning and mass balance the unm zagami is estimated to contain 20 5 or less cumulus pyroxene half augite and half pigeonite half the proportion suggested by equilibrium distribution of fe mg between pigeonite and melt this inconsistency may be resolved if all pigeonite melt element partitioning was affected by the rapid growth of the pigeonites the composition of the parental magma for the unm zagami calculated by mass balance on bulk and pyroxene compositions is similar to the 1170 c melt of the bmnh zagami not the 1140 c melt inferred as parental by other workers the inference that the pyroxene zoning patterns reflect only magmatic events is consistent with an igneous age of 180 m y for zagami

morphological impacts of the chilean megathrust earthquake mw 8 8 on coastal wetlands of high conservation value abstract the subduction earthquake mw 8 8 on february 27th 2010 which affected chile s south central coast 37 s produced a co seismic uplift of 1 4 m in coastal tubul raqui wetland area with abrupt morphological changes in order to determine the magnitude of the changes in this area of high conservation value salt marsh morphological features were identified and quantified by mapping the changing extent of the coverage of morphological features before 2009 and after 2011 2012 the tectonic disturbance rectified satellite images of seven study sites were created for the three years using google earth images and processed in arcgis the results indicate a total decline of 31 7 in the area of the morphological features and the emergence of 1 25 km2 of dried area salt pans and tidal creeks were severely affected with more than 90 loss in contrast there was a slight recovery of the tubul and raqui main river channel 12 and the tidal channels 8 5 between 2011 and 2012 mainly in the area near the river mouth the salt marsh cover by spartina densiflora showed slight variation after the co seismic uplift 14 6 demonstrating high tolerance in the face of high impact natural disturbances the changes and later evolution may be explained mostly by the action of the seismic cycle in subduction zones continuing to monitor state of the recovery of the salt marsh and other similar environments may help to understand the true role that the seismic cycle plays in the dynamics of coastal ecosystems as well as its incidence in the recovery process

mid to late holocene shoreline reconstruction and human occupation in ancient eretria south central euboea greece few studies have aimed to reconstruct landscape change in the area of eretria south central euboea greece during the last 6000 years the aim of this paper is to partially fill in this gap by examining the interaction between mid to late holocene shoreline evolution and human occupation which is documented in the area from the late neolithic to the late roman period with discontinuities evidence of shoreline displacements is derived from the study of five boreholes maximum depth of 5 25 m below the surface drilled in the lowlands of eretria based on sedimentological analyses and micro macrofaunal identifications different facies have been identified in the cores and which reveal typical features of deltaic progradation with marine lagoonal fluvio deltaic and fluvial environments in addition a chronostratigraphy has been obtained based on 20 ams 14c radiocarbon dates performed on samples of plant remains and marine lagoonal shells found in situ the main sequences of landscape reconstruction in the plain of eretria can be summarized as follows a marine environment predominated from ca 4000 to 3200 cal bc and a gradual transition to shallow marine conditions is observed ca 3200 3000 cal bc due to the general context of deltaic progradation west of the ancient city subsequently from ca 3000 to 2000 cal bc a lagoon occupied the area in the vicinity of the temple of apollo and the settlement s development was restricted to several fluvio deltaic levees thus severely limiting human activities in the plain from ca 2000 to 800 cal bc a phase of shallow marine presence prevailed and constrained settlement on higher ground forcing abandonment of the major part of the plain finally since the eighth century bc the sea has regressed southward and created the modern landscape

application of the equilibrium planform concept to natural beaches in northern ireland the equilibrium planform concept epc for bayed beaches has achieved wide currency in coastal morphodynamics the north coast of ireland comprises a series of discrete headland embayment beaches within which waves and currents recycle a finite sediment volume it is therefore an ideal setting in which to explore the applicability of the concept application of the approach to 9 embayment beaches on the north coast of ireland provides some insights into the application of the concept the planform of some beaches does correspond to that predicted while others do not those whose measured planform does not correspond to the predicted planform can be interpreted through a difficulty in identifying the wave diffraction point b disequilibrium on the beach sediment scarcity or excess c geological control of beach morphology the subjectivity in selecting the diffraction point renders alternative explanations difficult and reduces the utility of the approach on natural shorelines where significant irregularities render identification of such points difficult

tectonic development of the eastern mediterranean region the eastern mediterranean region is a classic area for the study of tectonic processes and settings related to the development of the tethyan orogenic belt the present set of research and synthesis papers by earth scientist from countries in this region and others provides an up to date interdisciplinary overview of the tectonic development of the eastern mediterrenean region from precambrian to recent key topics include continental rifting ophiolite genesis and emplacement continental collision extensional tectonics crustal exhumation and intraplate deformation e g active faulting alternative tectonic reconstructions of the tethyan orogen are presented and discussed with important implications for other regions of the world the book will be an essential source of information and interpretation for academic researchers geologists and geophysicists advanced undergraduates and also for industry professionals including those concerned with hydrocarbons minerals and geological hazards e g earthquakes

observations of morphological change and sediment transport on a steep gravel beach abstract observations of morphological change and swash sediment loads concurrent with measurements of water level waves and currents were obtained during a spring to spring tidal cycle on a steep macrotidal gravel beach in southwest england the wave conditions experienced during the field experiment were relatively calm and the significant inshore wave height and period averaged 0 4 m and 6 s respectively incident frequency water motions dominated the hydrodynamics and the phasing between water surface elevation and cross shore and alongshore currents was inconsistent with standing edge wave motion morphological change was directly related to maxima in shoreline elevation and four modes of berm adjustment identified regression and rollover in response to falling and rising water levels respectively and removal and reformation during and after storms respectively swash processes transported substantial amounts of sediment at rates comparable to sand beaches and the net transport under modal wave conditions was estimated to be 1 kg per swash onshore per unit metre beach width steep hydrodynamic gradients induced by the abrupt slope breaks of the step and berm are one of the main causes of the large morphological variability characteristic of gravel beaches

a quasi experimental setting of coarse clast transport by the 2010 chile tsunami bucalemu central chile abstract on 27th february 2010 a mw 8 8 earthquake occurred in central chile causing a tsunami that severely affected the central chilean coast in this study we present sedimentological data of the 2010 chile tsunami from the coastal town of bucalemu in central chile the tsunami deposited both fine grained sediments as well as cobbles and boulders the location offers a quasi experimental setting for coarse clast transport because an artificial pile of cobbles and boulders was piled there for construction purposes some days before the tsunami therefore the pre tsunami transport setting and transport distances are well defined additionally a local flow depth of ca 2 m and flow speed of ca 5 6 m s are deduced from eyewitness reports and video recordings the cobbles and boulders have been transported up to 155 m from the pile in landward direction the size of the quarried clasts was restricted to max 0 3 m3 and 720 kg bigger boulders were not available at the location even though calculations show that the tsunami would have been capable to transport them calculations of flow speeds required for the initialization of transport in different modes such as sliding rolling or saltation indicate that all clasts that were moved by the tsunami in landward direction were entrained by the flow given a minimum observed speed of 5 6 m s with 65 being transported by rolling and 35 by saltation the transported clasts are arranged in three groups positioned in morphological depressions on the coastal plain a landward fining trend is not present the arrangement of clasts originating from a pile and being deposited in distinctive groups entails that the landward transport of cobbles and boulders is a function of repeated entrainment transport and deposition by several waves of the tsunami wave train consequently we interpret the clast distribution as a result of a combination of the number of individual waves of the tsunami wave train their respective energies the local topography and the pre transport setting of a clast pile which releases wedged clasts with each successive wave

copper and nickel partitioning in iron meteorites trace element analyses using proton induced x ray emission pixe and synchrotron x ray fluorescence sxrf have been made on metal and troilite from 9 iron meteorites representing 5 geochemical groups nickel and copper distribution coefficients d troilitemetal vary by factors of 600 and 20 respectively correlate positively with kamacite band width and correlate negatively with bulk nickel content meteorites with bulk ni 1 while those with ni 10 have cu depleted troilite dcu 1 since magmatic evolution and partial melting will produce cu enriched troilite only the observation of cu depleted troilite in ni rich meteorites is evidence for subsolidus re equilibration a process which reduces dcu by transfer of cu to exsolving metal elemental redistribution may have played an important role in establishing the present chemical trends in iron meteorites

variability of shore and shoreline evolution shore and shoreline evolution both due to natural and human induced causes or factors can be variable over a wide range of different temporal and or spatial scales our capability to understand and especially predict this variability is still limited this can lead to misinterpretation of coastal change information which hampers informed decision making and the subsequent design and implementation of soft engineering interventions collecting and describing example observations of shore and shoreline variability is one way to support and improve such human intervention this paper describes causes and factors for the variability and the resulting possible evolutions of wave dominated shores and shorelines which are illustrated by a number of case studies the new element of this work is that the variability is described in terms of a range of different time and space scales which helps to structure such analysis however it is difficult to generalise the results for arbitrary situations especially on decadal time scales scientific and engineering improvements require more quantitative insight into the physical mechanisms behind the free and forced shore behaviour responsible for the variability

toward understanding tectonic control on the mw 8 8 2010 maule chile earthquake the maule earthquake of 27th february 2010 m w 8 8 affected similar to 500 km of the nazca south america plate boundary in south central chile producing spectacular crustal deformation here we present a detailed estimate of static coseismic surface offsets as measured by survey and continuous gps both in near and far field regions earthquake slip along the megathrust has been inferred from a joint inversion of our new data together with published gps insar and land level changes data using green s functions generated by a spherical finite element model with realistic subduction zone geometry the combination of the data sets provided a good resolution indicating that most of the slip was well resolved coseismic slip was concentrated north of the epicenter with up to 16 m of slip whereas to the south it reached over 10 m within two minor patches a comparison of coseismic slip with the slip deficit accumulated since the last great earthquake in 1835 suggests that the 2010 event closed a mature seismic gap slip deficit distribution shows an apparent local overshoot that highlight cycle to cycle variability which has to be taken into account when anticipating future events from interseismic observations rupture propagation was obviously not affected by bathymetric features of the incoming plate instead splay faults in the upper plate seem to have limited rupture propagation in the updip and along strike directions additionally we found that along strike gradients in slip are spatially correlated with geometrical inflections of the megathrust our study suggests that persistent tectonic features may control strain accumulation and release along subduction megathrusts c 2012 elsevier b v all rights reserved

application of the parabolic bay shape equation to sand and gravel beaches on mediterranean coasts abstract the equation most commonly used to describe the bay planform was proposed by hsu and evans 1989 and it was obtained through empirical analysis of sand beach planforms in the last decade interest in gravel sediments increased owing to their greater stability on beaches compared with sand sediments due to the differences between the morphodynamics of sand and gravel beaches which is strictly influenced by their different hydraulic characteristics it was necessary to create a predictive instrument for this beach type as well therefore in this study the standard hsu and evans equation 1989 was modified in order to make it applicable not only to sand beaches but also to gravel beaches the shoreline was computed according to a parabolic model in polar coordinates whose coefficients are considered linearly dependent on the wave direction and related to the beach type the estimation of the free parameters of the model was performed according to a statistical analysis of a shorelines data set of mediterranean sand and gravel embayed beaches

k ar dating of some infra ophiolitic metamorphic soles from the eastern mediterranean new evidence for oceanic thrustings before obduction abstract k ar dating on separated minerals from the infra peridotitic metamorphic soles outcropping beneath various eastern mediterranean ophiolite complexes pindos nappe in greece lycian antalya beysehir hoyran mersin and pozanti karsanti nappes in the taurides belt turkey baer bassit nappe in syria shows that the main metamorphic recrystallization of those rocks occurred 25 30 m y prior to the tectonic emplacement of the ophiolite complexes onto a continental platform these data support the hypothesis of an early slicing of the oceanic crust before its obduction advocated recently by several authors

heterogeneous plate locking in the south central chile subduction zone building up the next great earthquake abstract we use global positioning system gps velocities and kinematic finite element models fe models to infer the state of locking between the converging nazca and south america plates in south central chile 36 s 46 s and to evaluate its spatial and temporal variability gps velocities provide information on earthquake cycle deformation over the last decade in areas affected by the megathrust events of 1960 m w 9 5 and 2010 m w 8 8 our data confirm that a change in surface velocity patterns of these two seismotectonic segments can be related to their different stages in the seismic cycle accordingly the northern 2010 segment was in a final stage of interseismic loading whereas the southern 1960 segment is still in a postseismic stage and undergoes a prolonged viscoelastic mantle relaxation after correcting the signals for mantle relaxation the residual gps velocity pattern suggests that the plate interface accumulates slip deficit in a spatially and presumably temporally variable way towards the next great event though some similarity exist between locking and 1960 coseismic slip extrapolating the current decadal scale slip deficit accumulation towards the 300 yr recurrence times of giant events here does neither yield the slip distribution nor the moment magnitude of the 1960 earthquake this suggests that either the locking pattern is evolving in time to reconcile a slip deficit distribution similar to the 1960 earthquake or that some asperities are not persistent over multiple events the accumulated moment deficit since 1960 suggests that highly locked patches in the 1960 segment are already capable of producing a m 8 event if triggered to fail by stress transfer from the 2010 event

the experimental deformation of dunite deformation experiments have been carried out on two dunites anita bay of 100 m grain size and aheim of 900 m grain size at strain rates from 10 3 to 10 6 s 1 and temperatures from 1000 c to 1300 c in a gas medium deformation apparatus at 300 mpa confining pressure most of the tests were under wet conditions defined by the presence of small amounts of water from hydrous minerals initially present constant strain rate and relaxation experiments covering ranges of flow stress down to about 70 mpa and 7 mpa respectively show that there is a change in flow law in going below about 100 mpa differential stress and that the coarser grained rock is stronger than the finer grained one power law parameters above the transition are n 4 48 0 31 and q 498 38 kj mol 1 for aheim dunite and n 3 35 0 17 and q 444 24 kj mol 1 for anita bay dunite while below the transition relaxation tests on anita bay dunite give n 2 44 0 18 and q 386 27 kj mol 1 it is concluded that there is a weakening effect of water that this effect is mainly in the grain boundaries and that grain boundary sliding is probably a significant deformation mechanism at the lower stresses under wet conditions

historical changes in the shoreline and littoral processes on a headland bay beach in central chile abstract we applied parabolic and logarithmic adjustments and methods of cartographic overlay to the sandy littoral of concon bay central chile to determine the changes associated with the shoreline and their relation with littoral processes in a typical bay on an active continental margin and with a microtidal regime a set of historical reference points was built by means of aerial photographs and topographies for the period 1945 2008 given the form of the shoreline to the southern section of the bay we applied the classical logarithmic formula of yasso 1965 and the functions incorporated in the coastal modeling system sistema de modelamiento costero smc of the universidad de cantabria in the northern section a method of map overlay was applied the oluca sp model of the smc was used to determine the influence of waves refraction on the types of changes of the shoreline information on waves 1985 2006 mean sea level 2001 2006 and variations in the mean size of beach sediment were used to relate the changes in the plan form of the bay there has been little spatio temporal variability in the shoreline of the bay over the last 65 years the southern section had a mean shoreline retreat rate of 0 55 m year 1945 2008 in spite of the large variability produced in an estuary dominated by waves the best adjustment was obtained with the logarithmic function in the northern section the mean accretion rate was 0 39 m year 1954 2008 the plan form and the historical changes of the shoreline are closely associated with the seasonal changes of the waves and the presence of rocky thresholds in the area the mean sea level did not produce important effects in the types of change

a simple equilibrium model for predicting shoreline change abstract this contribution describes the development calibration and verification of a 1 d behaviour orientated shoreline prediction model the model primarily encapsulates shoreline displacement forced by wave driven cross shore sediment transport hysteresis effects are shown to be important and are included in the model whereby present shoreline change is influenced by past hydro morpho dynamic conditions the potential magnitude of shoreline change increases with incident wave power and the degree of disequilibrium the latter disequilibrium term eq is expressed in terms of the time evolving equilibrium eq and instantaneous dimensionless fall velocities and dictates the direction of shoreline movement following wright et al 1985 the equilibrium fall velocity is defined as a function of the weighted antecedent conditions and is a proxy for the evolving beach state the decay rate of the weighting function used to compute eq is a model free parameter determined by calibration against measured data which physically reflects the degree of observed memory of the system the decay in amplitude of this weighting function with time is controlled by a memory decay term where the weighting reaches 10 1 and 0 1 at 2 and 3 days prior to the current calculation time the model is applied to two multi year 6 years data sets incorporating hourly wave and weekly shoreline measurements from two contrasting energetic sites in se australia the first is the relatively dissipative straight gold coast qld and the second is a more intermediate embayed beach at narrabeen nsw the model shows significant skill at hindcasting shoreline change at both sites predicting approximately 60 of the total shoreline variability the gold coast shoreline is dominated by a strong seasonal signal conversely at the narrabeen embayment shoreline variability and morphology is more dynamic responding at storm frequency evidence suggests that there is a strong coherence between the shoreline position and morphodynamic state and that both have response times characterised by it is hypothesised that optimised values in the shoreline model physically relate to the efficiency of sediment exchanges between the shoreface and offshore bars and the prevalence of one or two dimensional horizontal circulation the general success of this new shoreline model for hindcasting the observed shoreline behaviour at two distinctly different open coast sites suggests that this approach may be suitable for broader application

headland bay beaches revisited an example from sandy hook new jersey abstract a variety of models have been successfully employed to describe the development of a crenulate logspiral type headland bay beach the success of these models has been attributed to the sheltering effect of the headland which results in a systematic distribution of wave energy for a short distance downdrift of the headland the decreasing influence of the headland on waves is thought to result in the curvilinear shoreline planform that is quantitatively described by a logarithmic or exponential function field data from south beach sandy hook new jersey were examined in an area which has historically exhibited a curvilinear headland bay beach and which was in the process of redeveloping such a configuration when data were collected the alongshore distribution of mean grain size beachface slope and an index reflecting slope and grain size showed no systematic trend there was no evidence of a systematic influence of the headland on wave energy it is suggested that the ubiquitous headland bay landform arises as a result of a general distance decay function away from the headland distance decay functions are typically curvilinear and easily fitted by logarithmic or exponential models not only wave processes but other factors such as sediment supply may be distributed as a distance decay function with respect to the headland resulting in a headland bay configuration

morphological recovery of beach severely damaged by the 2011 great east japan tsunami abstract the great east japan tsunami which occurred on 11 march 2011 the 2011 tsunami caused significant changes to the coastal and estuarine morphology along the sendai coast miyagi prefecture japan the recovery process which took place subsequently after the tsunami is investigated using aerial photographs bathymetry data and empirical orthogonal function eof method results from the aerial photograph analysis indicate that the shoreline was in the dynamic equilibrium condition in the period before the tsunami period 1 the recovery of the shoreline was very fast in the period of two years post event period 2 however it was more stable for the period of the next 4 5 years period 3 the analysis on the bathymetry data indicates that besides the sediment supply from adjacent coasts eroded sediment of the offshore seabed was transported onshore and led to a mass recovery of the shoreline at the lagoon areas the littoral system of the sendai coast also changed significantly between the periods before and after the tsunami as well as between periods 2 and 3 the sediment deposited inland and in the lagoon areas is perceived as the main reason that caused the retreat inwardly of about 70 m 80 m of the shoreline after the tsunami regarding the eof analysis the reflected coastal processes of the first three dominant components from the eof analysis for two shoreline data sets after the tsunami can be explained in period 2 the morphological recovery at severely damaged areas lagoons was the most dominant process whilst the second one was the cross shore variety of shoreline which was the most dominant process preceding tsunami the contribution rate of the first and second components in period 2 is about 4 times different in the period of the next 4 5 years period 3 the cross shore variety of shoreline which was induced by high waves came back to be the most dominant process whilst the second component reflects the longshore sediment transport these two dominant components are similar to the ones before the tsunami the contribution rates of the first two components before and after the tsunami are relatively close as well that confirms that the coastal processes have returned back to the conditions before the tsunami this is an important finding which is deduced from this study because a strong tsunami such as the 2011 tsunami could have been a major disturbance tipping the normal cross long shore variability of shoreface water interface towards a different regime

numerical modeling of crenulate bay shapes a numerical model is developed to compute the shoreline planform in a crenulate bay beach the new model combines polar and cartesian coordinates and can be used effectively to compute a hooked zone shoreline in the lee of upcoast headland the model is calibrated using laboratory data with an incident wave angle ranging from 25 to 60 the results of calibration and verification suggest that the ratio of the sediment transport parameters by wave and longshore current in this model is close to unity and the computed shoreline planforms for the hooked and unhooked zones are in good agreement with the ones measured especially when a bay is close to static equilibrium in addition the bay shape calculated by the present model is similar to that given by the well known empirical parabolic equation for a bay in static equilibrium the process of bay shape development from a straight beach to a static equilibrium bay is studied using laboratory experiments and the present numerical model the temporal variations in the computed longshore sediment transport at different locations within a bay beach are analyzed from this the decrease in the sediment transport becomes apparent while a bay beach changes its shape from straight toward a state of equilibrium based on this experience it may be concluded that the present numerical model can produce a temporal change in the shoreline planform of a crenulate bay beach from a transition state to static equilibrium subject to seasonal wave action

experimental investigations of trace element fractionation in iron meteorites ii the influence of sulfur abstract we have investigated the partitioning of ir ge ga w cr au p and ni between solid metal and metallic liquid as a function of temperature and s concentration of the metallic liquid partition coefficients for siderophile elements such as ir w ga and ge increase by factors of 10 100 as the sconcentration of the metallic liquid increases from 0 30 wt partition coefficients for other siderophile elements such as ni au and p increase by only factors of 2 3 in contrast partition coefficients for the more chalcophile element cr decrease these experimentally determined partition coefficients have been used in conjunction with a fractional crystallization model to reproduce the geochemical behavior of ni p au and ir during the magmatic evolution of groups iiab iiiab iva and ivb iron meteorites the mean s concentration for each group increases in the order ivb iva iiiab iiab in accord with cosmochemical prediction however we are unable to reproduce the geochemical behavior of ge ga w and cr in an internally consistent way we conclude that the magmatic histories of these iron meteorite groups are more complex than has been generally assumed

the elastic thickness of the lithosphere in the pacific ocean abstract in this study we present determinations of the effective elastic thickness t e of the oceanic lithosphere along pacific chains or archipelagoes t e is determined by computing the deflection of a continuous elastic plate under the load of volcanoes and constrained by geoid heights provided by seasat in the south central pacific estimates of 14 km for the marquesas and 6 km or less for the pitcairn mururoa gloucester chain are in good agreement with a previous work in this region cook austral and society chains around the line islands chain seasat data reveal that the bathymetry is poorly known preventing fine analysis meanwhile t e looks globally very low 6 km except for three volcanoes but these results may be unreliable the easter chain features low t e values 6 km with no noticeable variation along the chain higher values are found for a samoan island manuae 24 km and along the hawaiian emperor seamounts chain from 32 km at the eastern end of the chain to 21 5 km for the hawaiian volcanoes and from 25 5 to 15 km for the emperor seamounts the large number of t e estimates obtained in this study points out a noticeable difference between north and south pacific results those from the north pacific agree with the general trend increase with the square root of age plate at loading time while those from the south central pacific are much lower according to their plate age these low t e results from the south pacific are only partly explained by taking account of thermal perturbations using the rejuvenation model therefore these results then point out a regional difference in oceanic lithosphere

a numerical shoreline model for shorelines with large curvature abstract this paper presents a new numerical model for shoreline change which can be used to model the evolution of shorelines with large curvature the model is based on a one line formulation in terms of coordinates which follow the shape of the shoreline instead of the more common approach where the two orthogonal horizontal directions are used the volume error in the sediment continuity equation which is thereby introduced is removed through an iterative procedure the model treats the shoreline changes by computing the sediment transport in a 2d coastal area model and then integrating the sediment transport field across the coastal profile to obtain the longshore sediment transport variation along the shoreline the model is used to compute the evolution of a shoreline with a 90 change in shoreline orientation due to this drastic change in orientation a migrating shoreline spit develops in the model the dimensions of the spits evolving in the model compare favorably to previous model results and to field observation of the skaw spit in the north of denmark

the 2010 mw 8 8 maule megathrust earthquake of central chile monitored by gps large earthquakes produce crustal deformation that can be quantified by geodetic measurements allowing for the determination of the slip distribution on the fault we used data from global positioning system gps networks in central chile to infer the static deformation and the kinematics of the 2010 moment magnitude m w 8 8 maule megathrust earthquake from elastic modeling we found a total rupture length of 500 kilometers where slip up to 15 meters concentrated on two main asperities situated on both sides of the epicenter we found that rupture reached shallow depths probably extending up to the trench resolvable afterslip occurred in regions of low coseismic slip the low frequency hypocenter is relocated 40 kilometers southwest of initial estimates rupture propagated bilaterally at about 3 1 kilometers per second with possible but not fully resolved velocity variations

development of concepts concerning the genesis and emplacement of tethyan ophiolites in the eastern mediterranean and oman regions this article uses evidence mainly from the eastern mediterranean and oman to help understand the origin and emplacement of ophiolites field studies in these regions emphasize the diversity of ophiolite related sedimentary and tectonic processes topics to be discussed here include the sedimentary covers of ophiolites their metamorphic soles related melanges and emplaced continental margin slope rise units modes of ophiolite emplacement will also be considered and tectonic reconstructions that have a direct bearing on the origin and emplacement of ophiolites the writer argues that there is compelling evidence that many ophiolites formed by spreading above intraoceanic subduction zones evidence from their intact sedimentary covers however indicates that such subduction was only incipient in most cases as directly associated volcanic arcs or back arc basins are rare metamorphic soles record fragments of oceanic lithosphere derived from settings ranging from open ocean to continental slope rise settings underlying melanges record the subduction of most of the ocean lithosphere formed at spreading ridges continental margin units beneath ophiolites demonstrate that these ophiolites were formed in ocean basins that were mainly initiated by continental rifting in the eastern mediterranean and oman regions ophiolite emplacement was commonly achieved by trench margin collision although strike slip transpression and large scale accretion along subducting margins played a role in some cases taking account of the mesozoic palaeotectonic setting of the eastern mediterranean region it is widely believed that ophiolites of two main ages mid jurassic and late cretaceous were formed in several small oceanic basins separated by rifted microcontinents the history of tethys in pre mesozoic time remains more open to question lastly giant subduction related ophiolites as in oman cyprus or the balkans may not be forming anywhere in the world ocean today but may instead relate to rare events in earth history when regional to global plate boundaries were drastically reorganised

distribution of moderately volatile trace elements in fine grained chondrule rims in the unequilibrated co3 chondrite alh a77307 abstract the concentrations of ni cu zn ga ge and se in five fine grained chondrule rims in the highly unequilibrated co3 chondrite alh a77307 3 0 have been determined for the first time by synchrotron x ray fluorescence sxrf microprobe at brookhaven national laboratory these elements are especially useful for tracing the role of condensation and evaporation processes which occurred at moderate temperatures in the solar nebula understanding the distribution of moderately volatile elements between matrix and chondrules is extremely important for evaluating the different models for the volatile depletions in chondritic meteorites the data show that the trace element chemistry of rims on different chondrules is remarkably similar consistent with data obtained for the major and minor elements by electron microprobe these results support the idea that rims are not genetically related to individual chondrules but all sampled the same reservoir of homogeneously mixed dust of the trace elements analyzed zn and ga show depletions relative to ci chondrite values but in comparison with bulk co chondrites all the elements are enriched by 1 5 to 3 5 co the abundance patterns for moderately volatile elements in alh a77307 chondrule rims closely mimic those observed in the bulk chondrite indicating that matrix is the major reservoir for these elements the close matching of the patterns for the volatile depleted bulk chondrite and enriched matrix is especially striking for na which is anomalously depleted in alh a77307 in comparison with average co chondrite abundances the depletion in na is probably attributable to the effects of leaching in antarctica with the exception of na the volatile elements show a relatively smooth decrease in abundance as a function of condensation temperature indicating that their behavior is largely controlled by their volatility

shoreline change analysis and its application to prediction a remote sensing and statistics based approach abstract shoreline change analysis and prediction are important for integrated coastal zone management and are conventionally performed by field and aerial surveys this paper discusses an alternative cost effective methodology involving satellite remote sensing images and statistics multi date satellite images have been used to demarcate shoreline positions from which shoreline change rates have been estimated using linear regression shoreline interpretation error uncertainty in shoreline change rate and cross validation of the calculated past shorelines have been performed using the statistical methods namely regression coefficient r 2 and root mean square error rmse this study has been carried out along 113 5 km of coast adjoining bay of bengal in eastern india over the time interval 1973 to 2003 the study area has been subdivided into seven littoral cells and transects at uniform interval have been chosen within each cell the past and future shoreline positions have been estimated over two time periods of short and long terms in three modes viz transect wise littoral cell wise and regionally the result shows that 39 of transects have uncertainties in shoreline change rate estimations which are usually nearer to cell boundaries on the other hand 69 of transects exhibit lower rmse values for the short term period indicating better agreement between the estimated and satellite based shoreline positions it is also found that cells dominated by natural processes have lower rmse when considered for long term period while cells affected by anthropogenic interventions show better agreement for the short term period however on regional considerations there is not much difference in the rmse values for the two periods geomorphological evidence corroborates the results the present study demonstrates that combined use of satellite imagery and statistical methods can be a reliable method for shoreline related studies

rotational deformation in the jurassic mesohellenic ophiolites greece and its tectonic significance abstract the jurassic pindos and vourinos ophiolites in the western hellenides of greece are part of the mesohellenic mafic ultramafic slab underlying the eocene miocene sedimentary basin mesohellenic trough the tectonic incorporation of this oceanic slab into the western edge of the pelagonian subcontinent occurred via trench passive margin collision in the late jurassic much of the tectonic architecture of these ophiolites particularly vourinos was acquired during progressive inhomogeneous deformation associated with the initial displacement of the jurassic oceanic crust from its original igneous environment of formation and its subsequent tectonic emplacement eastward onto the pelagonian margin the heterogeneous deformation in the mantle and crustal sequences of the pindos vourinos ophiolites occurred in ductile ductile brittle and brittle fields synchronously as the jurassic oceanic lithosphere was translated eastward it also resulted in differential horizontal rotations within the displaced oceanic slab areas retaining high temperature diapiric mantle fabric appear to have been passively translated by lower temperature ductile shearing commonly along mylonite zones individual dunite bodies in the harzburgite tectonites indicate movement distances of at least kilometer scale pervasively mylonitic domains within the upper mantle peridotites suggest elongation on the order of five to ten times in the direction of ophiolite emplacement seafloor spreading related high temperature mantle structures within the pindos and vourinos ophiolites are sub parallel imprinted ductile kinematic indicators and ductile shear zones pervasive to the mantle and lower crustal sections in both ophiolites are also sub parallel consistent with the direction of tectonic vergence and appear traceable across the sedimentary overburden of the mesohellenic trough these geometric relations imply that the pindos vourinos ophiolites retain their relative orientations from the time of cessation of ductile deformation within the ophiolitic slab more than 90 anticlockwise horizontal rotation of the vourinos ophiolite seems to have taken place during progressive simple shear deformation associated with the eastward emplacement of the jurassic oceanic lithosphere this kind of rotational deformation postdating the igneous accretion of ancient oceanic crust may be common in many ophiolites and should be carefully distinguished from tectonic extension related vertical rotational deformation developed during their seafloor spreading evolution

slip distribution of the february 27 2010 mw 8 8 maule earthquake central chile from static and high rate gps insar and broadband teleseismic data 1 the shallow depth underthrust earthquake of february 27 2010 mw 8 8 ruptured the subduction plate interface in central chile between 34 s and 38 s we retrieve the spatial and temporal distribution of slip during this mega earthquake through a joint inversion of teleseismic records insar and high rate gps hrgps data additionally our model is shown to agree with broadband surface waves rupture initiated at about 32 km depth and propagated bilaterally resulting in two main slip zones located ssw and nne of the hypocenter nucleation did not take place within or at the edge of one of these main asperities but in between during the first 30s slip propagated predominantly southwards later on the rupture evolved more slowly and more symmetrically eventually the northern asperity became predominant with maximum slip reaching about 20 m most of the seismic moment was released within 110s a relatively short time explained by the bilateral propagation the overall average rupture velocity is 2 6 km s but propagation occurred initially faster towards the south 3 2 km s large slip did not reach the trench a result consistent with the moderate size of the tsunami down dip rupture stopped at about 50 km depth in agreement with the lower limit of the locked zone inferred by ruegg et al 2009 from pre seismic gps data

post earthquake coastal evolution and recovery of an embayed beach in central southern chile abstract earthquakes and tsunamis are significant factors for change along active margin shores and influence coastal evolution the chilean coast was affected in 2010 by a subduction earthquake with a magnitude of mw 8 8 and also by a trans pacific tsunami which generated violent geomorphologic changes and damaged homes following these events the magnitude of the changes which affect chile s central southern coast 37 s and the role of subduction earthquakes in coastal evolution on a historical scale were investigated at lebu bay an embayed beach data were generated for variations in time and space along the shoreline topographical and bathymetric changes in the bay and for morphodynamic littoral processes logarithmic and parabolic models were applied to the shoreline along with map overlays in order to determine changes the shoreline processes were analyzed based on statistics for waves tides and sediment transport for pre and post tsunami conditions an average accretion rate of 2 80 m year 1984 2010 was established for the shoreline with a strong trend towards accretion in the last 30 years a parabolic function best represented the general form of the shoreline although the presence of a river in the concave zone affected the fit in this sector two factors controlled historical changes on the beach one of anthropic origin in addition to the earthquake and tsunami on february 27th 2010 the post earthquake recovery was fast and currently the beach is in a stable condition despite the inter seismic subsidence process previous to the event this coastal system showed a high resilience in the face of coastal geomorphological changes induced by high impact natural disturbances however the opposite occurred in relation to changes induced by anthropogenic disturbances

limited overlap between the seismic gap and coseismic slip of the great 2010 chile earthquake the mw 8 8 chile earthquake on 27 february 2010 occurred in a broad region where tectonic loading has been accumulating since the great 1835 earthquake a joint inversion of tsunami and geodetic data suggests that the 2010 earthquake rupture only partly overlapped with the zone of preseismic locking

a new model for predicting three dimensional beach changes by expanding hsu and evans equation the empirical bay shape model proposed by hsu and evans in 1989 for predicting the static planform of a pocket beach is expanded to enable the calculation of three dimensional beach changes on a pocket beach with a seawall the original formulation was developed on the basis of a second order regression analysis unlike the one line model of shoreline changes the model of hsu and evans does not require repeated calculations of the wave field and shoreline position because it was derived on the assumption of null sediment movement within a pocket beach in static equilibrium hence without the need of applying the continuity condition of total sand volume in the calculation the expanded model proposed by the present authors satisfies the total sand budget on a pocket beach by taking into account the concept of depth change due to longshore sand transport model tests were carried out and the new model was further applied to the beach changes at kemigawa on the northeast of tokyo bay in chiba prefecture as well as at oarai in ibaraki prefecture japan on both locations seawall has been installed as countermeasures against beach erosion where wave sheltering effect of the main breakwater and beach changes in front of the seawall has also been observed with this expansion the present model can be applied to predict the three dimensional beach changes on a coast with seawall on a pocket beach

far field tsunami simulations of the 1755 lisbon earthquake implications for tsunami hazard to the u s east coast and the caribbean article i nfo the great lisbon earthquake of november 1st 1755 with an estimated moment magnitude of 8 5 9 0 was the most destructive earthquake in european history the associated tsunami run up was reported to have reached 5 15 m along the portuguese and moroccan coasts and the run up was significant at the azores and madeira island run up reports from a trans oceanic tsunami were documented in the caribbean brazil and newfoundland canada no reports were documented along the u s east coast many attempts have been made to characterize the 1755 lisbon earthquake source using geophysical surveys and modeling the near field earthquake intensity and tsunami effects studying far field effects as presented in this paper is advantageous in establishing constraints on source location and strike orientation because trans oceanic tsunamis are less influenced by near source bathymetry and are unaffected by triggered submarine landslides at the source source location fault orientation and bathymetry are the main elements governing transatlantic tsunami propagation to sites along the u s east coast much more than distance from the source and continental shelf width results of our far and near field tsunami simulations based on relative amplitude comparison limit the earthquake source area to a region located south of the gorringe bank in the center of the horseshoe plain this is in contrast with previously suggested sources such as marques de pombal fault and gulf of cadiz fault which are farther east of the horseshoe plain the earthquake was likely to be a thrust event on a fault striking 345 and dipping to the ene as opposed to the suggested earthquake source of the gorringe bank fault which trends ne sw gorringe bank the madeira tore rise mtr and the azores appear to have acted as topographic scatterers for tsunami energy shielding most of the u s east coast from the 1755 lisbon tsunami additional simulations to assess tsunami hazard to the u s east coast from possible future earthquakes along the azores iberia plate boundary indicate that sources west of the mtr and in the gulf of cadiz may affect the southeastern coast of the u s the azores iberia plate boundary west of the mtr is characterized by strike slip faults not thrusts but the gulf of cadiz may have thrust faults southern florida seems to be at risk from sources located east of mtr and south of the gorringe bank but it is mostly shielded by the bahamas higher resolution near shore bathymetry along the u s east coast and the caribbean as well as a detailed study of potential tsunami sources in the central west part of the horseshoe plain are necessary to verify our simulation results

the cu isotopic composition of iron meteorites abstract high precision cu isotopic compositions have been measured for the metal phase of 29 iron meteorites from various groups and for four terrestrial standards the data are reported as the 65cu permil deviation of the 65cu 63cu ratio relative to the nist srm 976 standard terrestrial mantle rocks have a very narrow range of variations and scatter around zero in contrast iron meteorites show 65cu approximately 2 3 variations different groups of iron meteorites have distinct 65cu values nonmagmatic iab iiicd iron meteorites have similar 65cu 0 03 0 08 and 0 12 0 10 respectively close to terrestrial values approximately 0 the other group of nonmagmatic irons iie is isotopically distinct 0 69 0 15 ivb is the iron meteorite group with the strongest elemental depletion in cu and samples in this group are enriched in the lighter isotope 65cu down to 2 26 evaporation should have produced an enrichment in 65cu over 63cu 65cu 0 and can therefore be ruled out as a mechanism for volatile loss in ivb meteorites in silicate bearing iron meteorites 17o correlates with 65cu this correlation between nonmass dependent and mass dependent parameters suggests that the cu isotopic composition of iron meteorites has not been modified by planetary differentiation to a large extent therefore cu isotopic ratios can be used to confirm genetic links cu isotopes thus confirm genetic relationships between groups of iron meteorites e g iab and iiicd iiie and iiiab and between iron meteorites and chondrites e g iie and h chondrites several genetic connections between iron meteorites groups are confirmed by cu isotopes e g iab and iiicd iiie and iiiab and between iron meteorites and chondrites e g iie and h chondrites

geochemistry and petrogenesis of ophiolites from northern pindos greece the ophiolitic complex of northern pindos greece contains ocean floor basalts and low ti mafic rocks the former rocks are similar to recent mid ocean ridge basalts with a light ree depletion and a la yb ratio 2 the low ti rocks resemble boninites in their high mg and very low ti and zr contents and in their ree patterns which have convex downwards shape with a slight light ree enrichment however their zr ti ti v and zr y ratios are lower than in boninites both rock types could be generated by dynamic partial melting of a rising upper mantle diapir slight enrichment in light ree sr rb and ba in low ti rocks could be the result of either metasomatic or alteration processes although a subduction zone origin of the sequence is possible the geochemical data do not necessarily imply such a setting

morphodynamics of structurally controlled headland bay beaches in southeastern brazil a review abstract this paper presents a comprehensive review on the interaction between hydrodynamic processes beach morphology and sedimentology at large scale coastal behaviour along the coastline of santa catarina between laguna and sao francisco island a microtidal east coast swell environment with headland and bay geomorphologies the parabolic bay shape equation has proven to be a convenient and practical tool for studying the stability of the headland bay beaches tombolos and salients in santa catarina the beaches exhibit different patterns of sediment removal as a function of the degree of beach curvature in highly curved beaches there is a well developed shadow zone and a range of morphodynamic conditions from a sheltered low energy beach adjacent to the downdrift headland to a high energy exposed beach on the straight end of the headland bay beach the less curved beaches instead tend to show more uniform behaviour since they are directly exposed to incident waves there is no obvious relationship between average wave height and mean grain size showing the importance of sediment source to characterize the sedimentary distribution patterns in the study area the analysis of beaches showed that beach morphodynamics and sequence profiles for a bay headland coast in a microtidal east coast environment is a function of geological inheritance e g distance between headlands and orientation nearshore and inner shelf morphology coastal plain morphology and sediment source and hydrodynamic factors wave conditions oceanic wave exposure and relative tidal range

land level changes produced by the mw 8 8 2010 chilean earthquake we observed vertically displaced coastal and river markers after the 27 february 2010 chilean earthquake moment magnitude mw 8 8 land level changes range between 2 5 and 1 meters evident along an approximately 500 kilometers long segment identified here as the maximum length of coseismic rupture a hinge line located 120 kilometers from the trench separates uplifted areas to the west from subsided regions a simple elastic dislocation model fits these observations well model parameters give a similar seismic moment to seismological estimates and suggest that most of the plate convergence since the 1835 great earthquake was elastically stored and then released during this event

central chile finally breaks chile is the site of some of the largest earthquakes in the world on average a magnitude 8 earthquake occurs there every 10 years or so these earthquakes take place in the subduction zone either as interplate ruptures at the interface between the south american and nazca plates or as intraplate events within the subducted nazca plate a few times in every century massive plate interface earthquakes break several hundred kilometers in a single shock this is what happened on 27 february 2010 when a major earthquake magnitude 8 8 occurred in the maule and biobio regions in central chile see the first figure this region had last experienced a major subduction earthquake in 1835 when darwin 1 visited the area as part of his voyage on the beagle his description of the earthquake inspired many seismologists and historians of chilean earthquakes 2 3