precambrian medusoids the cyclomedusa plexus and cyclomedusa like pseudofossils abstract the medusoid fossils that were conventionally referred to cyclomedusa sprigg 1947 are among the commonest elements of the late precambrian ediacara metazoan assemblage in south australia specimens showing varying degrees of similarity have been reported worldwide from precambrian occurrences this study indicates that the fossils traditionally named cyclomedusa are a morphological plexus consisting of heterogeneous medusae the type species c davidi sprigg and c radiata sprigg are considered as a single species because of differences due to preservation c davidi can be compared with a living hydrozoan medusa aequorea in general configuration and an affinity with the family aequoreidae is suggested for the typical cyclomedusa spriggia southcott 1949 which was once regarded as a synonym of cyclomedusa is now re interpreted as a float bearing chondrophore hydrozoan colonial medusa the newly described s wadeae sp nov provides remarkable evidence for the amazingly conservative evolutionary history of the family porpitidae c plana glaessner and wade 1966 may be also chondrophoran in affinity but its configuration remains uncertain a critical review on the previously supposed cyclomedusa and other medusoids from the upper precambrian in southern liaoning china demonstrates that they are cyclomedusa like pseudofossils made by upwards escaping gas bubbles and water currents therefore they can not be used for stratigraphic correlation this example suggests the need for extreme caution in studies of various cyclomedusa like circular structures

ediacaran fossils from the miette group rocky mountains british columbia canada the discovery of metazoan fossils in the upper part of the hadrynian miette group windermere supergroup extends the range of the cosmopolitan ediacara fauna late vendian to a new region and brings to six the number of genera now known in western north america the fossils provisionally identified as cyclomedusa davidi irridinitus sp and protodipleurosoma sp occur in a greenish gray shallow water siltstone that surrounds stromatolite mounds established on the yellowhead platform in the mount robson provincial park the locality is stratigraphically about 330 m below the unconformably overlying mcnaughton formation gog group of probable cambrian age

predicting coastal hazards for sandy coasts with a bayesian network abstract low frequency high impact storm events can have large impacts on sandy coasts the physical processes governing these impacts are complex because of the feedback between the hydrodynamics of surges and waves sediment transport and morphological change predicting these coastal changes using a numerical model requires a large amount of computational time which in the case of an operational prediction for the purpose of early warning is not available for this reason morphodynamic predictions are not commonly included in early warning systems ewss however omitting these physical processes in an ews may lead to potential under or over estimation of the impact of a storm event to solve this problem a method has been developed to construct a probabilistic bayesian network bn this bn connects three elements offshore hydraulic boundary conditions characteristics of the coastal zone and onshore hazards such as erosion and overwash depths and velocities the hydraulic boundary conditions are derived at a water depth of approximately 20 m from a statistical analysis of observed data using copulas and site characteristics are obtained from measurements this bn is trained using output data from many pre computed process based model simulations which connect the three elements once trained the response of the bn is instantaneous and can be used as a surrogate for a process based model in an ews in which the bn can be updated with an observation of the hydraulic boundary conditions to give a prediction for onshore hazards the method was applied to praia de faro portugal a low lying urbanised barrier island which is subject to frequent flooding using a copula based statistical analysis which preserves the natural variability of the observations a synthetic dataset containing 100 events was created based on 20 years of observations but extended to return periods of significant wave height of up to 50 years these events were transformed from offshore to onshore using a 2d xbeach roelvink et al 2009 model three bn configurations were constructed of which the best performing one was able to predict onshore hazards as computed by the model with an accuracy ranging from 81 to 88 and predict events with no significant onshore hazards with an accuracy ranging from 90 to 95 two examples are presented on the use of a bn in operational predictions or as an analysis tool the added value of this method is that it can be applied to many coastal sites 1 limited observations of offshore hydrodynamic parameters can be extended using the copula method which retains the original observations natural variability 2 the transformation from offshore observations to onshore hazards can be computed with any preferred coastal model and 3 a bn can be adjusted to fit any relevant connections between offshore hydraulic boundary conditions and onshore hazards furthermore a bn can be continuously updated with new information and expanded to include different morphological conditions or risk reduction measures as such it is a promising extension of existing ewss and as a planning tool for coastal managers

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

transformation of an archean craton margin during proterozoic basin formation and magmatism the albany fraser orogen western australia abstract the albany fraser orogen is a well preserved example of proterozoic modification of an archean craton margin the formation of two successive basin systems accompanied by magmatism along the southern and southeastern yilgarn craton margin in western australia reflect distinct changes in tectonic regimes resulting in significant transformations of the archean craton crust provenance analysis from detrital zircons indicates that the first basin system the c 1815 1600 ma barren basin was dominantly filled with neoarchean detritus derived from the yilgarn craton and paleoproterozoic detritus derived from coeval voluminous mostly felsic magmatism the abundance of locally derived sediment deposited onto a reworked archean yilgarn craton substrate coupled with the progressively more juvenile isotopic signature of magmas indicates a largely extensional tectonic setting consistent with either a continental rift basin or a long lived backarc basin system this extensional regime led to the formation of a passive margin and oceanic basin along the craton edge the c 1600 1305 ma arid basin and formation of an ocean continent transition in the most heavily modified outboard region of the craton margin the eastern nornalup zone a change in tectonic regime is denoted by the formation of an oceanic arc the c 1410 ma loongana arc preserved in the adjoining madura province oceanic subduction led to accretion of the loongana arc onto the craton edge recorded by the presence of exotic detritus derived from this arc deposited into a foreland basin uppermost arid basin this accretion event triggered crustal thickening and the earliest phase of magmatism of stage i of the albany fraser orogeny at c 1330 ma a change to west dipping subduction beneath the accreted portion of the loongana arc placed the orogen into a backarc setting into which the remainder of the recherche supersuite mafic and felsic magmas were intruded thus the albany fraser orogen is regarded as an archean craton margin that preserves a long history of proterozoic transformation dominated by extensional processes that resulted in the formation of orogen wide basin systems accompanied by magmatism the recognition that the albany fraser orogen has always been part of the west australia craton and the tectonic regimes that have affected it provide important constraints on reconstructions of the nuna and rodinia supercontinents

modelling gravel barrier profile response to combined waves and tides using xbeach laboratory and field results abstract xbeach a process based numerical model capable of computing nearshore circulation and morphodynamics including overwash and breaching has been used in 1d mode to simulate erosion occurring on a gravel barrier beach d50 11 mm subjected to wave and tidal forcing during selected tests undertaken during the bardex experiments the model demonstrated good quantitative skill brier skill score bss typically 0 65 with respect to beach face erosion offshore accretion and morphological impacts of washover xbeach was also used to model storm impacts on a steep average tan 0 12 4 5 km long and 100 m 140 m wide macrotidal gravel barrier d50 2 mm to 10 mm located in sw england although the development of a storm berm was not reproduced well erosion was predicted with sufficient skill bss 0 60 to meet practical engineering requirements concerned with predicting storm impacts and threshold wave and water level conditions for gravel barrier overwashing

beach response to breakwater layouts of drainage pipe outlets during beach nourishment abstract managing drainage pipes to optimize beach nourishment is a complex problem in this study the salient landform is explored as a feasible plan that considers beach nourishment and breakwater geometry of the drainage pipe outlets the xbeach model was used to establish an idealized model for analyzing the beach response to three typical breakwater layouts straight landward convex and seaward convex the seaward convex breakwater layout was found to be the most effective option because it can accumulate the largest volume of sediment behind the structure the seaward convex layout was also used to analyze the beach response to incident wave angles ranging from 0 normal to the shore to 60 as the incident wave angle increases the volume of sand salient accumulated in the leeward of the breakwater and the flow speed in the cross show direction gradually decrease while the wave height and the flow speed in the along shore direction gradually increase however there is a critical angle of approximately 50 at which opposite trends of changes in bed level wave height and eulerian flow occur

satellite based constraints on explosive so2 release from soufriere hills volcano montserrat 1 numerous episodes of explosive degassing have punctuated the 1995 2009 eruption of soufriere hills volcano shv montserrat often following major lava dome collapses we use ultraviolet uv and infrared ir satellite measurements to quantify sulfur dioxide so2 released by explosive degassing which is not captured by routine ground based and airborne gas monitoring we find a total explosive so2 release of 0 5 tg which represents 6 of total so2 emissions from shv since july 1995 the majority of this so2 0 4 tg was vented following the most voluminous shv dome collapses in july 2003 and may 2006 based on our analysis we suggest that the so2 burden measured following explosive disruption of lava domes depends on several factors including the instantaneous lava effusion rate dome height above the conduit and the vertical component of directed explosions space based so2 measurements merit inclusion in routine gas monitoring at shv and other dome forming volcanoes

an analysis of the cross shore beach morphodynamics of a sandy and a composite gravel beach in this paper beach profile surveys acquired over more than a decade at a sandy beach narrabeen beach new south wales australia and a composite sand gravel beach milford on sea christchurch bay uk are analysed to compare and contrast cross shore morphodynamics of the two beach types the different behavioural characteristics of the two beach types at decadal inter annual and intra annual time scales are investigated comparisons of beach profiles with dean s equilibrium profile and vellinga s erosion profile show that the dean s profile satisfactorily represents the time mean profiles of both beach types statistical and empirical orthogonal function eof analyses confirm the generally accepted model that the inter tidal zone is the most morphodynamically active region on a sandy beach whereas the swash zone is the most dynamic region on a mixed sand gravel beach the results also imply that during storms composite sand gravel beaches may become unstable due to cutback of the upper beach while sandy beaches are more likely to be unstable as a result of beach lowering due to sediment transport from the inter tidal zone to the sub tidal zone during storms eof results also show that milford on sea beach is in a state of steady recession while the narrabeen beach shows a cyclic erosion accretion variability a multivariate technique canonical correlation analysis cca shows that on the composite beach a strong correlation exists between incident wave steepness and profile response which could be attributed to the unsaturated surf zone whereas on the sandy beach any correlation is much less evident

paleoproterozoic increase in zircon δ18o driven by rapid emergence of continental crust abstract numerous geologic proxies for earth system processes track dramatic changes at the atmosphere lithosphere or atmosphere ocean interface during the early paleoproterozoic era the presence of a geodynamic driver for these changes and how this might have affected the deeper lithosphere is more cryptic here we present temporally constrained 18o and ehf in detrital zircon from paleoproterozoic sedimentary successions in western australia and canada that chart a rapid change in the oxygen isotopic composition from

a probability method for predicting time dependent long term shoreline erosion this paper describes a practical procedure for predicting the probability distributions of long term shoreline erosion it treats the dynamical response of the shoreline over time as that of a time dependent stochastic system the input to the system are the long term wave climate and shoreline properties while the output of the system are the probability distributions of the maximum shoreline recession within any prescribed time period the procedure enables the combined effect of the longshore and cross shore sediment transport processes on the shoreline erosion to be taken into account as both processes are generally responsible for the maximum shoreline recession a series of simulations using idealised long term wave distributions which have relatively narrow directional spread was carried out to evaluate the capability of the method based on these simulations it was found that both the distributions and variability of wave climates have significant influence on the predicted shoreline erosion probability distributions while the chronology effect is less significant especially for long simulation time

the southern oscillation index wave climate and beach rotation short embayed beaches bounded by headlands are a common feature along the southern and central coastline of new south wales australia many of these embayed beaches have experienced severe erosion at their southern end over the last decade previous studies have suggested that this erosion may be the result of an oscillatory medium term phenomenon known as beach rotation the present study was undertaken with the objectives of 1 establishing definitive links between the southern oscillation index soi wave climate and beach rotation and 2 determining the physical processes governing beach rotation data from two similar new south wales beaches were analysed using time series analysis techniques and image processing techniques using argus video images in this study the results indicate that the northern end of this type of beach accretes during el nino phases while the southern end erodes resulting in a net clockwise rotation of the beach the opposite occurs during la nina phases resulting in a net anti clockwise rotation of the beach the beach response at the northern and southern ends lags soi trend shifts by 3 and 17 months respectively waves are predominantly incident from the southeast during both el nino and la nina phases offshore wave height is positively correlated with the soi while offshore wave direction is negatively correlated with the soi on average the number of storms per year doubles from el nino to la nina based on these links between beach width fluctuations soi and incident wave conditions a conceptual model of beach rotation is presented the model describes the combinations of cross shore and longshore sediment transport and hydrodynamic processes that are expected to result in the observed clockwise and anti clockwise beach rotation during el nino and la nina phases respectively

shoreline recovery on wave dominated sandy coastlines the role of sandbar morphodynamics and nearshore wave parameters abstract this study quantifies and characterises the temporal variability of shoreline recovery on a high energy sandy coastline using a 10 year dataset of daily shoreline and sandbar positions from a coastal imaging station at narrabeen collaroy beach australia following a total of 82 individual storm events rates of the cross shore return of the shoreline to its pre storm position were analysed observed rates during shoreline recovery were characterised by an overall mean of 0 2 m day temporal variability in rates was most evident at shorter timescales of 1 2 weeks and included rates most frequently between 0 and 0 3 m day less frequent more rapid rates of up to 2 m day and also minor landward movements this temporal variability was significantly correlated with nearshore forcing parameters describing the ratio of wave height to wave period the cross shore proximity and attachment of the sandbar to the shoreline and the rate of cross shore sandbar migration these findings are summarised in a new conceptual model that characterises temporal phases and rates of shoreline recovery corresponding to stages of onshore sandbar migration following a storm from fully detached storm deposited sandbar morphology through to complete sandbar welding with the shoreline more gradual shoreline recovery rates are observed with fully detached and semi attached sandbar conditions in contrast more rapid rates of shoreline recovery occur when sandbars are closer and attached to the shoreline observed to be on average 3 4 times greater than for detached sandbars in conditions with attached and semi attached sandbars shoreline recovery rates are negatively correlated to the forcing of nearshore wave steepness and dimensionless fall velocity and coupled with concurrent rates of onshore sandbar migration the findings provide insight into key parameters influencing shoreline recovery following storms

modelling storm impacts on beaches dunes and barrier islands a new nearshore numerical model approach to assess the natural coastal response during time varying storm and hurricane conditions including dune erosion overwash and breaching is validated with a series of analytical laboratory and field test cases innovations include a non stationary wave driver with directional spreading to account for wave group generated surf and swash motions and an avalanching mechanism providing a smooth and robust solution for slumping of sand during dune erosion the model performs well in different situations including dune erosion overwash and breaching with specific emphasis on swash dynamics avalanching and 2dh effects these situations are all modelled using a standard set of parameter settings the results show the importance of infragravity waves in extending the reach of the resolved processes to the dune front the simple approach to account for slumping of the dune face by avalanching makes the model easily applicable in two dimensions and applying the same settings good results are obtained both for dune erosion and breaching

gondwanaland significance of lower palaeozoic deformation in central india and sw western australia the stirling range formation of western australia and the vindhyan supergroup of central india have undergone two identical lower palaeozoic deformation events folding related to dextral reactivation of basement structures suggests a possible continuation of the indian narmada son brahmaputra lineament into sw western australia subsequent open folding during ne sw crustal shortening in both terranes is possibly related to gondwanaland assembly whilst the shillong group in ne india appears similar to the stirling range formation and vindhyan supergroup further geochronology is required to substantiate a common tectonic history

statistical simulation of wave climate and extreme beach erosion abstract recent developments in extreme values modelling have been used to develop a framework for determining the coastal erosion hazard on sandy coastlines this framework quantitatively reproduced the extreme beach erosion volumes obtained from field measurements at narrabeen beach australia this encouraging finding was achieved using kriebel and dean s kriebel d l and dean r g 1993 convolution method for time dependent beach profile response journal of waterway port coastal and ocean engineering 119 2 204 226 simple beach erosion and accretion model the method includes allowances for joint probability between all basic erosion variates including wave height period and direction event duration tidal anomalies and event spacing a new formulation for the dependency between wave height and period has been developed it includes the physical wave steepness limitation event grouping where significantly more erosion can occur from two closely spaced storms is handled by temporally simulating the synthetic wave climate and the resulting beach erosion and accretion

magma fragmentation by rapid decompression the processes leading to magma fragmentation and the generation of pyroclastic debris during explosive volcanic eruptions are of fundamental importance in volcanology observations of explosive eruptions1 3 as well as theoretical analyses of the underlying processes4 have raised the question of whether the rapid decompression of highly viscous vesicular magma that results from the collapse of a lava dome or volcanic edifice can in itself produce explosive magma fragmentation and pyroclast formation here we report the results of a laboratory investigation of pyroclast formation following rapid decompression samples of magma from the 1980 eruption of mount st helens when rapidly depressurized from initial pressures of up to 12 mpa and at temperatures in the range 750 825 c fragmented to form pyroclastic products that are in many respects similar to those formed in real eruptions moreover we observe explosive fragmentation at temperatures well below those normally associated with magmatic processes suggesting that even relatively cool magma bodies can be very hazardous when subjected to rapid unloading events

influence of storm sequencing on breaker bar and shoreline evolution in large scale experiments abstract new large scale experiments on the influence of storm sequencing on beach profile evolution are presented the experiments comprised three sequences that commenced from the same initial beach profile each sequence consisted of two storms of different energy with each storm followed by a recovery phase a specific focus of the experiments was the influence of storm chronology as well as the influence of the recovery wave energy and duration on beach evolution the breaker bar and the shoreline are studied as indicators for the beach response both evolve towards an equilibrium location for each wave condition where the breaker bar reaches its equilibrium much faster than the shoreline overall no enhanced beach erosion due to storm sequencing is observed despite a similar cumulative wave power of the three sequences the final beach configuration of each sequence seems to be determined by the last wave condition instead of previous storms however storm sequencing is important when the beach profile has not yet fully recovered before being disrupted by the subsequent storm in this case the second storm does not necessarily cause further erosion but can result in onshore sediment transport and hence form part of the recovery the bulk onshore sediment transport as well as the shoreline recovery rate vary depending on the wave condition and the profile disequilibrium and show a maximum value for a recovery condition with an intermediate wave energy the very low energy condition that was performed for a long duration 24 hours generated a near stationary beach profile with typical features of a reflective beach

depositional architecture of a wave dominated clastic shoreline pilmatue member argentina linking dynamics and stratigraphic record of bar trough systems abstract bar trough morphologies are a dominant feature of modern wave dominated clastic shorelines despite these barred configurations being widely described from modern systems there is still some uncertainties associated with their interpretation in the ancient record there is a lack of detailed outcrop based studies describing the facies distribution and architecture within bar trough systems which causes a disparity between observations of modern processes and the subsequent preserved rock record this work presents a detailed characterization and interpretation of the sedimentary record of a bar trough setting this was achieved through the analysis of nearshore i e upper shoreface and foreshore deposits within a parasequence in the lower cretaceous pilmatue member of the agrio formation neuquen basin argentina a high resolution facies and architectural analysis was developed combining detailed sedimentary logs with the mapping of bounding and internal surfaces within the nearshore deposits the facies analysis suggests that trough and planar cross bedded facies are remnants of dunes in the upper shoreface due to a strong influence of longshore currents while planar laminated facies would be the result of swash processes in the foreshore additionally the presence of a well defined surf diastem the persistent low angle obliquity of palaeocurrents and the preservation of concave upward stratigraphic surfaces led to the interpretation of those deposits as representing the production of a bar trough configuration with longshore currents distributing large amounts of sediment along the shore this analysis allowed us to reconstruct the dominant processes for sediment transport and deposition within these barred nearshore settings and to identify different key architectural surfaces for the upper shoreface and foreshore deposits the architectural analysis of such surfaces led to define four different orders of hierarchy which respond to depositional and erosional processes operating at different scales the comparison between different resulting architectures of wave dominated barred shoreline offers the possibility to improve in the palaeoenvironmental reconstructions for ancient or recent successions the proposed model for bar trough clastic shoreline successions relates an absence of bar related deposits to major storms and shoreline erosional processes this conceptual model offers a new interpretation for explaining the mid scale evolution of bar trough settings and the relationship between the modern and ancient record

ediacaran fossils from the stirling range formation western australia abstract metazoan body fossils of ediacaran affinity in the stirling range formation of western australia represent the first discovery in western australia thereby extending the biogeographic range of the australian ediacaran fauna although small size and poor preservation limits accurate classification body fossils have been classified with varying degrees of confidence to genus cyclomedusa sprigg 1947 in addition to ediacaran body fossils a single float sample containing simple protuberances was discovered these discoids were assigned to the ichnogenus bergaueria prantl 1945 whilst previously considered to have been deposited and deformed along with basement gneiss during the mesoproterozoic the presence of ediacaran fossils indicates a significantly younger timing for deposition and hence for deformation of the stirling range formation

rip current type spacing and persistence narrabeen beach australia abstract long term daily rip observations on narrabeen beach australia were made together with daily measurements of wave height period direction surf zone width and beach state a total of 3513 rips were observed on 270 days over a 19 month period results show that rips accompany moderate to high waves and are associated with intermediate beach types rip spacing follows wave conditions increasing in spacing size and intensity as waves rise and conversely as they fall rips are a function of both the prevailing and antecedent wave conditions and the rate and direction of change in wave conditions rips are classified into three types erosion mega and accretion erosion rips are initiated by rising seas in the transverse bar and rip and higher beach states they accompany general beach erosion they are widely spaced narrabeen ys 300 500 m 100 200 m increasing in size and intensity with the waves until the fully dissipative ripless state is reached they are both temporally and spatially highly variable persisting in one location for only hours to a day or so except where topographically controlled they are a major mechanism for the seaward transport of sediment and under extreme conditions may extend over a kilometer seaward of the breaker zone mega rips are large scale 1 km topographically controlled erosion rips that persist when nearshore and or embayment topography prevents the development of the fully dissipative state by inducing wave refraction and persist longshore gradients in surf zone dynamics that in turn drive the rip circulation accretion rips prevail during stable or falling wave conditions usually following erosion rip formation they are associated with general beach accretion are more closely spaced narrabeen ys 170 250 m 100 m less intense and become increasingly topographically arrested by crescentic bars and rhythmic bar beach morphology of the longshore bar trough rhythmic bar and beach and transverse bar and rip beach states they are relatively stable both spatially and temporally and may persist in one location for days to weeks if wave conditions remain favorable they are fair weather rips which may disappear by infilling in the low tide terrace beach state or be destroyed by rising seas rips generally are absent from the reflective low tide terrace and fully dissipative beach states

infrared satellite observations of hydrogen sulfide in the volcanic plume of the august 2008 kasatochi eruption 1 hydrogen sulphide h2s is one of the main trace gases released from volcanoes with yearly global emissions estimated between 1 and 37 tg with sulfur dioxide so2 15 21 tg year it dominates the volcanic sulfur budget and the emission ratio h2s so2 is an important geochemical probe for studying source conditions sulfur chemistry and magma water interactions contrary to so2 measurements of h2s are sparse and difficult here we report the first measurements of a large h2s plume from space observations were made with the infrared sounder iasi of the volcanic plume released after the 7 8 august 2008 eruption of kasatochi volcano the eruption was characterized by 5 consecutive explosive events the first events were phreatomagmatic producing a plume rich in water vapor and poor in ash and so2 we show that the observed h2s plume calculated at 29 10 kt with integrated columns exceeding 140 25 dobson units du is likely associated with these first explosions h2s so2 ratios with maximum values of 12 2 are found representative of redox conditions in the hydrothermal envelop with a detection threshold of 25 du future space observations of h2s plumes are certain these will be important for improving the atmospheric sulfur budget and characterizing the h2s so2 fingerprint of different eruptions

beach response to a sequence of extreme storms abstract a sequence of daily beach surveys acquired over one month covering an area larger than 100 000 m 2 was analyzed to study morphological changes resulting from a cluster of storms the beach response was highly variable in both the cross and alongshore a cumulative storm effect was not observed despite one storm being characterized by a 10 year return period that had significant wave height h s of 8 1 m and a peak wave period t p of 17 s instead storms that can potentially cause significant erosion in terms of h s had a limited effect on the morphology because the large wave height was coupled to either neap tides normally incident short waves f 0 04 hz or low levels of infragravity 0 004 f

storm impact on the seasonal shoreline dynamics of a meso to macrotidal open sandy beach biscarrosse france abstract a three year dataset 2007 2010 of shoreline and sandbar positions derived from video observations of an open sandy beach biscarrosse france is analyzed to explore the impact of storms on the seasonal shoreline dynamics the results indicate that a clear seasonality is observed in the offshore significant wave height and in the occurrence of winter storm events that are defined as periods with significant wave height greater than 4 m lasting at least 12 h data indicate that the range of variation of the inner sandbar positions 120 m is two and a half times larger than the range of variation of the shoreline position correlation analyses suggest that the offshore conditions do not conclusively explain the position of the inner bar shoreline positions show a clear seasonal pattern displaying a stable position occurring in february and july providing evidence of seasonal recovery although analysis of storm activity indicates that the number and intensity of storms is highly variable over the three years the biscarrosse data show that rapid erosion can be observed also under moderate conditions and that beach recovery after the storm season can be relatively rapid

beach erosion and recovery during consecutive storms at a steep sloping meso tidal beach this study analyses beach morphological change during six consecutive storms acting on the meso tidal faro beach south portugal between 15 december 2009 and 7 january 2010 morphological change of the sub aerial beach profile was monitored through frequent topographic surveys across 11 transects measurements of the surf swash zone dimensions nearshore bar dynamics and wave run up were extracted from time averaged and timestack coastal images and wave and tidal data were obtained from offshore stations all the information combined suggests that during consecutive storm events the antecedent morphological state can initially be the dominant controlling factor of beach response while the hydrodynamic forcing and especially the tide and surge levels become more important during the later stages of a storm period the dataset also reveals the dynamic nature of steep sloping beaches since sub aerial beach volume reductions up to 30 m3 m were followed by intertidal area recovery 2 z 3 m with rates reaching 10 m3 m however the observed cumulative dune erosion and profile pivoting imply that storms even of regular intensity can have a dramatic impact when they occur in groups nearshore bars seemed to respond to temporal scales more related to storm sequences than to individual events the formation of a prominent crescentic offshore bar at 200 m from the shoreline appeared to reverse the previous offshore migration trend of the inner bar which was gradually shifted close to the seaward swash zone boundary the partially understood nearshore bar processes appeared to be critical for storm wave attenuation in the surf zone and were considered mainly responsible for the poor interpretation of the observed beach behaviour on the grounds of standard non dimensional morphological parameters copyright 2011 john wiley sons ltd

daily monitoring of ecuadorian volcanic degassing from space we present daily measurements of sulfur dioxide so2 emissions from active volcanoes in ecuador and southern colombia between september 2004 and september 2006 derived from the ozone monitoring instrument omi on nasa s eos aura satellite omi is an ultraviolet visible spectrometer with an unprecedented combination of spatial and spectral resolution and global coverage that permits daily measurements of passive volcanic degassing from space we use non interactive processing methods to automatically extract daily so2 burdens and information on so2 sources from the omi datastream maps of monthly average so2 vertical columns retrieved by omi over ecuador and s colombia are also used to illustrate variations in regional so2 loading and to pinpoint sources the dense concentration of active volcanoes in ecuador provides a stringent test of omi s ability to distinguish so2 from multiple emitting sources our analysis reveals that tungurahua reventador and galeras were responsible for the bulk of the so2 emissions in the region in the timeframe of our study with no significant so2 discharge detected from sangay at galeras and reventador we conclude that omi can detect variations in so2 release related to cycles of conduit sealing and degassing which are a critical factor in hazard assessment the omi so2 data for reventador are the most extensive sequence of degassing measurements available for this remote volcano which dominated regional so2 production in june august 2005 at tungurahua the omi measurements span the waning stage of one eruptive cycle and the beginning of another and we observe increasing so2 burdens in the months prior to explosive eruptions of the volcano in july and august 2006 cumulative so2 loadings measured by omi yield a total of 1 16 tg so2 emitted by volcanoes on mainland ecuador s colombia between september 2004 and september 2006 as much as 95 of this so2 may originate from non eruptive degassing approximate apportionment of the total so2 loading indicates that 40 originated from tungurahua with 30 supplied by both reventador and galeras these measurements of volcanic so2 degassing in ecuador confirm omi s potential as an effective economical and risk free tool for daily monitoring of so2 emissions from hazardous volcanoes

storm sequencing and beach profile variability at hasaki japan abstract beach profile evolution under storm sequence forcing presents an emerging research topic that has only been investigated at a limited number of sites the occurrence and effects of storm sequencing on beach profile evolution are studied at hasaki beach japan using weekly beach profile and two hourly offshore wave measurements during the 25 year study period the supratidal beach at hasaki is subjected to long term accretion and steepening while the shoreline shows a long term oscillation in addition oscillations of the supratidal beach volume and the shoreline at semi annual and annual intervals are identified which are largely controlled by the variability of the wave height hasaki beach is subjected to frequent storms that often cluster in sequences especially during the extra tropical cyclone season january to march the majority of storms and sequences generate erosion of the beach above the low water level but some also lead to recovery despite a tendency for storms and storm sequences with larger power to cause more erosion the present data does not demonstrate increased beach erosion by storm sequences following these findings the tendency of the beach to evolve towards equilibrium and the importance of the antecedent beach morphology are demonstrated

ediacaran fossils and dubiofossils miette group of mount fitzwilliam area british columbia shallow water clastic beds flanking stromatolitic carbonate mounds in the upper part of the vendian miette group windermere supergroup of the rocky mountains contain a poorly preserved soft bodied fauna that comprises morphologically very variable discoid remains these include the taxa beltanella sp cf b grandis charniodiscus sp irridinitus sp nimbia occlusa protodipleurosoma sp cf p rugulosum and zolotytsia sp and seven types of dubiofossils

shoreline resilience to individual storms and storm clusters on a meso macrotidal barred beach abstract this study investigates the impact of individual storms and storm clusters on shoreline recovery for the meso to macrotidal barred biscarrosse beach in sw france using 6 years of daily video observations while the study area experienced 60 storms during the 6 year study period only 36 storms were analysed due to gaps in the video data based on the 36 individual storms and 13 storm clusters analysed our results show that clustering impact is cumulatively weak and shoreline retreat is governed by the first storms in clusters while the impact of subsequent events is less pronounced the average post storm beach recovery period at this site is 9 days consistent with observations at other beaches apart from the dominant effect of present storm conditions shoreline dynamics are also significantly affected by previous storm influence while recovery is strongly modulated by tidal range and the bar location our results reveal that not only is the storm energy important but also the frequency of recurrence storms result in greater retreat when time intervals between them are longer which suggests an interaction between short storm events and longer term evolution

syn tectonic hematite growth in paleoproterozoic stirling range red beds albany fraser orogen australia evidence for oxidation during late stage orogenic uplift abstract the timing of hematite growth in ancient red colored sedimentary rocks red beds is controversial while most of the hematite is considered to have formed at or near the land surface shortly after deposition paleomagnetic evidence suggests that some hematite in ancient red beds formed long after deposition during orogenic fluid flow metamorphosed red sandstones and shales in the stirling range formation western australia were deposited in a shallow marine environment between 2 0 and 1 8 billion years ago the sandstones which preserve an assemblage of discoidal and trace like fossils are stained red by abundant fine grained hematite crystals the hematite is aligned in a spaced cleavage defined by elongate laths of muscovite and chlorite and its occurrence as inclusions in 1 2 ga metamorphic monazite indicates that the oxide formed during the 1 2 1 15 ga albany fraser orogeny 600 million years after deposition thermometry of two distinct populations of chlorite an earlier fe chlorite chl1 and a later mg chlorite chl2 indicates a cooling trend from 370 c chl1 to 290 c chl2 consistent with evidence for rapid late stage uplift elsewhere in the orogen the results indicate that most of the hematite in the stirling red beds formed during syn to late orogenic oxidation of previously more reduced marine sediments the migration of oxidizing fluids during orogenesis possibly related to rapid uplift and gravity driven influx of surface water could explain the origin of other post orogenic red beds

the ichnotaxonomy of conostichus and other plug shaped ichnofossils the systematics of the single entrance plug shaped soft substrate trace fossils have long been in need of revision at least 15 ichnogenera comprising 32 ichnospecies have been used but an exa

the predictability of cross shore bed evolution of sandy beaches at the time scale of storms and seasons using process based profile models deterministic and probabilistic profile models have been compared with hydrodynamic and morphodynamic data of laboratory and field experiments on the time scale of storms and seasons the large scale laboratory experiment is a pure 2d case and offers and ideal test case for cross shore profile models as disturbing alongshore non uniformities are absent the field experiments are performed at the egmond site the netherlands during the eu coast3d project and represent storm time scale oct nov 1998 as well as seasonal time scale conditions may 1998 sep 1999 the objective of the paper is to present information of coastal processes on these time scales and to assess the predictive capabilities coastal process based profile models with respect to hydrodynamics and morphodynamics at sandy beaches on the time scales of storms and seasons profile models can quite accurately errors smaller than 10 represent the cross shore significant wave height distribution in the surf zone if the wave breaking model is properly calibrated the wave breaking coefficient should be a function of local wave steepness and bottom slope for most accurate results profile models can reasonably represent the cross shore and longshore currents undertow in a pure 2d case and in 3d field conditions profile models including cross shore mixing effects and breaker delay effects do not produce better predictions of the longshore and cross shore current velocities profile models using default settings can quite reasonably simulate the behaviour of the outer and inner bars on the storm time scale the behaviour of the beach cannot be modelled with sufficient accuracy on the storm time scale profile models can reasonably simulate the post storm onshore bar migration provided that the near bed orbital velocities and wave asymmetry related sand transport are represented in a sufficiently accurate way using non linear wave theories profile models cannot simulate the beach recovery processes on the post storm time scale because these essentially 3d processes are not sufficiently known to be included in the models profile models using default settings cannot simulate the behaviour of the outer and inner bars and the beach on the seasonal time scale the behaviour of the outer bar on the seasonal time scale can only be represented properly after tuning using measured bed profiles the simulation of the inner bar and beach morphology on the seasonal time scale could not be improved by tuning

foredune morphological changes and beach recovery from the extreme 2013 2014 winter at a high energy sandy coast the beach dune response at truc vert sw france is analysed using dgps topographic surveys sampled every 2 4 weeks covering an alongshore distance of 1 5 km combined with wave tide and extreme water level hindcast and beach dune photographs during the 2013 2014 winter which was the most energetic since at least 1948 the beach dune system at truc vert eroded by approximately 180 m3 per beach width divided equally between beach and dune erosion beach and dune erosion was strongly variable alongshore with cuspate type rhythmic dune erosion scarps stripped of vegetation with a cross shore amplitude of 25 m the alongshore variable scarps were coupled with an alongshore variability in elevation of the beach with lower beach levels co located with the megacusp bays the following 10 months showed modest morphological beach and dune changes with for instance destabilisation of the scarped dune by trough blowouts scarp slumping and filling and seasonal beach berm dynamics the most profound morphological and vegetation changes occurred during the subsequent 10 months only 1 5 years after that winter the beach dune system at truc vert almost recovered to its pre winter volume but not to its pre winter foredune profile most of the sand volume recovery occurred during spring summer autumn 2015 when approximately 120 m3 m of sand naturally came back in the system the beach volume recovery rate was relatively steady and uncorrelated with wave conditions with rates twice as large across the megacusp bay profile as across the that of the megacusp horns during that period the widened and risen dry beach provided large fetch length enhancing onshore windblown transport and a rapid rising of the backshore the slumped and filled dune scarp which was providing a high barrier to aeolian transport from the beach to the dune since the 2013 2014 winter reformed as a dune ramp providing efficient conduit for beach dune delivery exchange of sediment by the end of the study this process favoured both natural revegetation into the scarp and incipient foredune formation despite the reinstatement of natural processes between the beach and the dune the dune foot was still located landward by more than 10 m on average with respect to its pre 2013 2014 winter position this study shows that even after the most severe winter over the last 68 years in terms of average wave energy arriving at the coast beach recovery can be a relatively fast process along high energy sandy beaches backed by large dunes in contrast foredune recovery which timing and magnitude can provide a proxy measure for the resilience of the system to climatic variability and change is a much slower process that can take years to decades

effects of storm clustering on beach dune evolution abstract impacts of storm clustering on beach dune morphodynamics were investigated by applying the state of the art numerical model xbeach to formby point sefton coast uk the adopted storm cluster was established by analysing the observed winter storms from december 2013 to january 2014 using a storm threshold wave height the first storm that occurred during this period is regarded as exceptionally intense and the occurrence of such a cluster of events is very unusual a 1d model was setup for the highly dynamic cross shore at formby point after initial calibration of the model parameters against available post storm profile data the model was used for the simulation of the storm cluster it was assumed that no beach recovery occurred between adjacent storms due to the very short time intervals between storms as a result the final predicted post storm profile of the previous storm was used as the pre storm profile of the subsequent storm the predicted evolution during each storm was influenced by the previous storms in the cluster due to the clustering effect the bed level change is not proportional to the storm power of events within the cluster as it would be in an individual storm case initially the large storm events interact with the multi bared foreshore enabling the subsequent weaker storms to influence the upper beach and lower dune system this results in greater change at the dune toe level also during less severe subsequent storms it is also shown that the usual water level threshold used to define dune erosion is over predicted by about 1 m for extreme storm conditions the predicted profile evolution provides useful insights into the morphodynamic processes of beach dune systems during a storm cluster using formby point as an example which is very useful for quantifying the clustering effects to develop tools for coastal management

fossils and matgrounds from the neoproterozoic longmyndian supergroup shropshire uk body and trace fossils of ediacaran affinity are described from strata of the late neoproterozoic longmyndian supergroup exposed near church stretton shropshire uk the almost spherical soft bodied ediacaran fossil beltanelliformis brunsae menner occurs rarely in the burway formation but much smaller simpler discoidal structures are common in both the burway and synalds formations and are referred to beltanelliformis minutae sp nov similar discoidal structures but with a distinct central depression are included in intrites punctatus fedonkin and are common at several horizons two blocks with numerous examples of medusinites aff asteroides sprigg glaessner wade were recovered from the burway formation the purported ediacaran body fossil arumberia glaessner walter is common at several horizons but its biogenicity is not accepted herein arumberia is thus treated along with evidence for microbially bound sediment surfaces or matgrounds that have been suggested by several authors to be necessary for some types of ediacaran preservation the assemblage of simple trace and body fossils along with matgrounds is typical of latest neoproterozoic time though some elements range into the phanerozoic

in situ measurements of tropospheric volcanic plumes in ecuador and colombia during tc4 a nasa dc 8 research aircraft penetrated tropospheric gas and aerosol plumes sourced from active volcanoes in ecuador and colombia during the tropical composition cloud and climate coupling tc 4 mission in july august 2007 the likely source volcanoes were tungurahua ecuador and nevado del huila colombia the tc 4 data provide rare insight into the chemistry of volcanic plumes in the tropical troposphere and permit a comparison of so 2 column amounts measured by the ozone monitoring instrument omi on the aura satellite with in situ so 2 measurements elevated concentrations of so 2 sulfate aerosol and particles were measured by dc 8 instrumentation in volcanic outflow at altitudes of 3 6 km estimated plume ages range from 2 h at huila to 22 48 h downwind of ecuador the plumes contained sulfate rich accumulation mode particles that were variably neutralized and often highly acidic a significant fraction of supermicron volcanic ash was evident in one plume in plume o 3 concentrations were 70 80 of ambient levels downwind of ecuador but data are insufficient to ascribe this to o 3 depletion via reactive halogen chemistry the tc 4 data record rapid cloud processing of the huila volcanic plume involving aqueous phase oxidation of so 2 by h 2o 2 but overall the data suggest average in plume so 2 to sulfate conversion rates of 1 2 h 1 so 2 column amounts measured in the tungurahua plume 0 1 0 2 dobson units are commensurate with average so 2 columns retrieved from omi measurements in the volcanic outflow region in july 2007 the tc 4 data set provides further evidence of the impact of volcanic emissions on tropospheric acidity and oxidizing capacity

the effects of storm clustering on beach profile variability abstract impacts of storms in reshaping coastlines are well known also the far greater impact of clusters of storms where storms occur at close succession has been noted in a number of previous studies in this paper we analyse and discuss the storm wave climate and the beach profile response to clusters of storms at narrabeen beach new south wales australia narrabeen beach is subjected to frequent storms all year round and the beach undergoes substantial variability as a result the impact of storm clusters with closely spaced individual storms reaching the beach is investigated by combining historic measurements of beach profile surveys and numerical modelling of storm induced beach change our analysis of storm power index of storm clusters and its correlation with the change in beach width reveals that the strengths of single storms in a storm cluster alone are not the reason for beach change but time interval between successive storms and the post storm recovery speed of the beach concerned also play important roles we have quantified and compared beach erosion return levels resulting from single storms and storm clusters it was found that beach erosion volumes resulting from storm clusters with two or more storms resemble potential beach erosion volumes induced by single storms of far higher return periods

sedimentology structure and shrimp zircon provenance of the woodline formation western australia implications for the tectonic setting of the west australian craton during the paleoproterozoic abstract the paleoproterozoic woodline formation forms a 50 km long northeast trending belt of metasedimentary rocks that unconformably overlies archean granites and greenstones of the eastern goldfields superterrane near the southeastern margin of the yilgarn craton the woodline formation is dominated by mature quartz rich sandstone units interbedded with siltstones and represents the remnants of a broader siliciclastic sequence deposited along a passive margin after c 1737 ma the formation is weakly deformed and metamorphosed to lower greenschist facies with upright northeast trending folds resulting from northwest southeast shortening during the albany fraser orogeny between 1345 ma and 1140 ma an extensional event at c 1210 ma is recorded by the emplacement of the northeast trending fraser dyke swarm and formation of the grabens that preserved the woodline formation three hundred and seventy one u pb shrimp detrital zircon analyses from six samples from coarse grained sandstone units of the woodline formation indicate a maximum depositional age of 1737 28 ma 95 confidence the age data from all six samples show heterogeneity of age spectra from the eoarchean to the paleoproterozoic with an up sequence diversification of source terranes significant probability maxima at 2687 ma 2655 ma and 2629 ma are consistent with erosion of the underlying archean granite greenstone rocks of the eastern goldfields superterrane and the adjacent terranes of the yilgarn craton in comparison the paleoproterozoic zircons with maxima at 2245 ma 2034 ma and 1886 ma do not match known tectonomagmatic events within the west australian craton correlation of detrital zircon results from the woodline formation with other paleoproterozoic siliciclastic units around the margin of the yilgarn reveal a remarkable similarity with the earaheedy group especially with the paleoproterozoic age peaks indicating a common protosource s that is either buried no longer exists or is part of an exotic terrane beyond the west australian craton

the so2 camera a simple fast and cheap method for ground based imaging of so2 in volcanic plumes 1 so2 flux is widely monitored on active volcanoes as it gives a window into the hidden subsurface magma dynamics we present here a new approach to so2 flux monitoring using ultraviolet imaging of the volcanic plume through carefully chosen filters to produce images of so2 column amount the so2 camera heralds a breakthrough in both our ability to measure so2 flux at unprecedented frequencies 2 hz and at unprecedented accuracy thanks to the application of correlation techniques to determine wind speed directly from the images and the ability to measure the whole profile simultaneously in this paper we detail the commercially available pieces required to construct the so2 camera introduce a retrieval scheme to determine so2 amounts from the images and present results from a field campaign in november 2005 on sakurajima volcano japan

breaker bar morphodynamics under erosive and accretive wave conditions in large scale experiments abstract differences between breaker bar evolution under high energy erosive and subsequent mild energy accretive wave conditions are studied based on three data sets from large scale morphodynamic experiments under erosive wave conditions a clear linear relationship between the height and the cross shore location of the breaker bar is observed the similar cross shore shape of the sediment transport magnitudes underlines the similarity of the bar evolution under erosive wave conditions under the subsequent accretive wave conditions two major evolution patterns are observed during onshore migration decaying or non decaying breaker bar in the presented data the feedback between the wave conditions and the beach morphology determines if a bar decays during onshore migration this feedback involves that the wave breaking location depends on the morphology and on the wave conditions resulting in differences in sediment transport patterns between the two types of onshore bar migration a comparison against numerous other experimental beach profile data sets strongly supports the linear relationship between bar height and bar location under erosive wave conditions for accretive wave conditions the number of comparable data sets is very limited the comparison underlines that breaker bar evolution under accretive wave conditions cannot be condensed to a single pattern as under erosive wave conditions

radiative transfer corrections for accurate spectroscopic measurements of volcanic gas emissions there is widespread use of passive remote sensing techniques to quantify trace gas column densities in volcanic plumes utilizing scattered sunlight as a light source examples include passive doas cospec and the so2 camera in order to calculate trace gas concentrations or volcanic emission fluxes knowledge about the optical path through the plume is necessary in the past a straight photon path through the plume has always been assumed although it was known that this is not always true here we present the results of model studies conducted specifically to quantify the effects of realistic radiative transfer in and around volcanic plumes on ground based remote sensing measurements of so2 the results show that measurements conducted without additional information on average photon paths can be inaccurate under certain conditions with possible errors spanning more than an order of magnitude both over and underestimation of the true column density can occur actual errors depend on parameters such as distance between instrument and plume plume so2 concentration plume aerosol load as well as aerosol conditions in the ambient atmosphere as an example a measurement conducted with an so2 camera is discussed the results of which can only be correctly interpreted if realistic radiative transfer is considered finally a method is presented which for the first time allows the retrieval of actual average photon paths in spectroscopic i e doas measurements of adequate resolution by allowing for a wavelength dependent column density during the evaluation of doas measurements we show how radiative transfer effects can be corrected using information inherently available in the measured spectra thus greatly enhancing the accuracy of doas measurements of volcanic emissions

a biota of ediacaran aspect from lower cambrian strata on the digermul peninsula arctic norway three elements of the ediacara fauna are described from lower cambrian strata on the digermul peninsula norway nimbia occlusa fedonkin 1980 and tirasiana sp occur approximately 80 m above the base of the lower breivik member which approximately coincides with the neoproterozoic cambrian boundary a specimen of cyclomedusa sp has also been found in the lower duolbasgaissa member about 600 m above the boundary in rocks of trilobite bearing age these discoveries add to a growing body of evidence that some elements of the dominantly neoproterozoic ediacara fauna continue into the phanerozoic thereby diminishing the scope of a possible late neoproterozoic mass extinction event the taxa described here particularly nimbia and cyclomedusa also occur at many other localities within neoproterozoic strata and in common with other elements of the ediacara fauna display remarkable morphological variation some of this diversity in form is probably caused by environmental and preservational factors the possibility that it may at least in part reflect an inability of these early life forms to replicate faithfully their genes during reproduction should however not be overlooked

comparison of storm cluster vs isolated event impacts on beach dune morphodynamics two dimensional numerical simulations were used to investigate the impacts of storm clustering on the beach dune evolution of the sefton coast liverpool bay uk a storm cluster consisting of a series of closely spaced seven events was identified using observed wave and surge data during the 2013 2014 winter period first event in this cluster is regarded as exceptionally intense and the occurrence of seven storms within a very short time period is unique the xbeach coastal area model was used to simulate beach change from 1 the storm sequence clustered events and 2 the same storms considering them as isolated events offshore metadata was transformed to the nearshore area using the delft3d and swan models resulting evolution was first compared with the available post storm profiles measured at a number of locations along the sefton coast analysis of the clustered and isolated simulations showed the effect of clustering on the sefton beach dune system when compared to the impact of isolated events occurring on a fully recovered beach system morphological change occurred during each storm in the cluster was influenced by the preceding storm s such that the evolution is not proportional to the storm power of the event as it would be for isolated events both storm cases resulted in heavy erosion at formby point i e central of the sefton coast and accretion in the north and south the cluster prevented system recovery with the area of erosion continually extending south along the coast compared with that in isolated events the initial storm within the cluster caused large bed level changes in the nearshore ridge runnel system enabling the subsequent storms to penetrate further south the local convex geometry of the sefton coast is found to have more influence on the beach dune morphodynamics than the clustering effect this study enhances the understanding beach dune response to storm clusters to interpret observed morphological changes and to develop tools for sustainable coastal management particularly in the sefton coast and generally in similar systems worldwide

ash from the eyjafjallajokull eruption iceland fragmentation processes and aerodynamic behavior 1 the fragmentation process and aerodynamic behavior of ash from the eyjafjallajokull eruption of 2010 are investigated by combining grain size scanning electron microscopy sem and quantitative particle morphology ash samples were collected on land in iceland at 3 55 km distance from the volcanic vent and represent various phases of the pulsating eruption the grain size is fine even for deposits close to the vent suggesting that the parent particle population at fragmentation consisted of a substantial amount of fine ash sem investigation reveals that ash produced during the first phase of the eruption consists of juvenile glass particles showing key features of magma water interaction suggesting that phreatomagmatism played a major role in the fragmentation of a vesicle poor magma in the last phase of the eruption fragmentation was purely magmatic and resulted from stress induced reaction of a microvesicular fragile melt the shape of ash as determined by quantitative morphology analysis is highly irregular rendering the settling velocity quite low this makes transportation by wind much easier than for other more regularly shaped particles of sedimentary origin we conclude that the combination of magma s fine brittle fragmentation and irregular particle shape was the main factor in the extensive atmospheric circulation of ash from the mildly energetic eyjafjallajokull eruption

latest proterozoic stratigraphy and earth history the end of the proterozoic eon was a time of pronounced biological biogeochemical climatic and tectonic change new bio and chemostratigraphic data provide an improved framework for stratigraphic correlation making possible a deeper understanding of latest proterozoic earth history and providing tools for a chronostratigraphic division of late proterozoic time

impact of the winter 2013 2014 series of severe western europe storms on a double barred sandy coast beach and dune erosion and megacusp embayments abstract the winter of 2013 2014 was characterized by a striking pattern of temporal and spatial extreme storm wave clustering in western europe the 110 km long gironde coast sw france was exposed to the most energetic wave conditions over the last 18 years the period was outstanding in terms of the available energy to move sediment and cause large scale erosion with the 2 month average significant wave height hs exceeding 3 6 m just below the 0 95 quantile and 4 distinct 10 year return period storms with hs 9 m these storm waves caused unprecedented beach and dune erosion along the gironde coast including severely damaged sea defences at the coastal towns at the end of the winter dune erosion scarp height was highly variable alongshore and often exceeded 10 m megacusp embayments were observed along the gironde coast with an average alongshore spacing of 1000 m in the south progressively decreasing to 500 m in the north with an average cross shore amplitude of 20 m while beach megacusps were previously observed to systematically couple to the inner bar along the gironde coast during low to moderate energy wave conditions severe storm driven megacusp embayments cutting the dune were found to be enforced and coupled to the outer crescentic bar a detailed inspection of the 1500 m long bimonthly topographic surveys of truc vert beach shows that in early january 2014 the outstanding shore normal incident storm swell hercules with hs and peak wave period tp peaking at 9 6 m and 22 s respectively triggered the formation of a localized megacusp embayment with the erosion scarp height exceeding 6 m in its centre where the dune retreat reached 30 m the subsequent storms progressively smoothed the megacusp by the end of the winter mostly through severe erosion of the megacusp horns because of the very long period 16 s

space and ground based measurements of sulphur dioxide emissions from turrialba volcano costa rica remotely sensed measurements of sulphur dioxide so2 emitted by turrialba volcano costa rica are reported for the period september 2009 january 2011 these measurements were obtained using images from advanced spaceborne thermal emission and reflexion radiometer ozone monitoring instrument and a ground based uv camera these three very different instruments provide flux measurements in good agreement with each other which demonstrate that they can be integrated for monitoring so2 fluxes fluxes from turrialba increased fourfold in january 2010 following a phreatic explosion that formed a degassing vent in the w crater of turrialba since then the so2 flux has remained high 30 50 kg s but seems to be showing a slowly decreasing trend we interpret this evolution as the start of open vent degassing from a recently intruded magma body the opening of the degassing vent decreased the confining pressure of the magma body and allowed the gases to bypass the hydrothermal system

modelling storm induced beach dune evolution sefton coast liverpool bay uk storm induced dune evolution on a sandy coastal system is investigated using a nested modelling approach applied to the sefton coast liverpool bay uk real time offshore water levels and waves were used as model boundary forcings a delft3d coarse grid setup is used to simulate time and space varying sea surface elevations on which offshore waves are transformed by applying the swan model to establish the wave boundary for the high resolution morphological model xbeach statistical comparisons between model predicted and measured post storm profiles at a number of locations along the coast suggest that xbeach successfully captures storm induced beach change along the sefton coast predicted bed evolution of the beach dune system shows alternate erosion and sedimentation areas in the nearshore strong bed level changes are found at the northern part of the sefton coast when north westerly nw extreme waves and winds coincide with spring high tide morphological changes in the southern part are significantly lower than that in the north as a result of nw wave dissipation on the shoals located to the north of the crosby channel which creates low wave actions in that area in addition erosion of the dune foot is observed at some locations along the beach temporal simulation of beach dune evolution as a result of variable forcing conditions during storms provides useful insight into the morphodynamic processes of beach dune systems during storms using sefton as an example which is very useful for developing coastal management strategies over the existing conceptual tools

neoproterozoic sinistral displacement along the darling mobile belt western australia during gondwanaland assembly evidence is provided for neoproterozoic sinistral displacement along the darling mobile belt between greater india and precambrian terranes of western australia a dilatational bend in the shear zone is thought to have controlled emplacement of alkali granites anorthosite and mafic intrusives of the leeuwin complex which was deformed during progressive deformation faults formed in this event extend across the albany mobile belt and control the formation of the stirling basin on the southern margin of the yilgarn craton the regional extent of this event and the rotation of mesoproterozoic trends in the albany mobile belt through 90 suggests that the darling mobile belt may be part of a shear system of regional importance during assembly of proto east gondwanaland much attention is being focused on the assembly of gondwanaland and the relative displacements between archaean cratons along proterozoic mobile belts e g powell 1993 unrug 1994 yoshida 1994 southwestern australia is a key area within proto east gondwanaland as in reconstructions such as de witt et al 1988 and powell et al 1988 it constitutes the junction between the archaean yilgarn craton of western australia india greater india and the east antarctic shield fig 1 this paper examines the timing and nature of displacements along the darling mobile belt glikson lambert 1973 mathur shaw 1982 on the western margin of the yilgarn craton and contemporaneous structures within the albany mobile belt and southern yilgarn craton fig 2 the darling mobile belt the darling mobile belt referred to by myers 1990 as the

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

early evolution of a stratospheric volcanic eruption cloud as observed with toms and avhrr this paper is a detailed study of remote sensing data from the total ozone mapping spectrometer toms and the advanced very high resolution radiometer avhrr satellite detectors of the 1982 eruption of el chichon mexico the volcanic cloud atmosphere interactions in the first four days of this eruption were investigated by combining ultraviolet retrievals to estimate the mass of sulfur dioxide in the volcanic cloud krueger et al 1995 with thermal infrared retrievals of the size optical depth and mass of fine grained 1 10 m radius volcanic ash wen and rose 1994 our study provides the first direct evidence of gravitational separation of ash from a stratospheric gas rich plinian eruption column and documents the marked differences in residence times of volcanic ash and sulfur dioxide in volcanic clouds the eruption column reached as high as 32 km carey and sigurdsson 1986 and was injected into an atmosphere with a strong wind shear which allowed for an observation of the separation of sulfur dioxide and volcanic ash the upper more sulfur dioxide rich part of the cloud was transported to the west in the stratosphere while the fine grained ash traveled to the south in the troposphere the mass of sulfur dioxide released was estimated at 7 1 109 kg with the mass decreasing by approximately 4 1 day after the peak the mass of fine grained volcanic ash detected was estimated at 6 5 109 kg amounting to about 0 7 of the estimated mass of the ash which fell out in the mapped ash blanket close to the volcano over the following days 98 of this remaining fine ash was removed from the volcanic cloud and the effective radius of ash in the volcanic cloud decreased from about 8 m to about 4 m

volcano monitoring applications of the ozone monitoring instrument the ozone monitoring instrument omi is a satellite based ultraviolet uv spectrometer with unprecedented sensitivity to atmospheric sulphur dioxide so2 concentrations since late 2004 omi has provided a high quality so2 dataset with near continuous daily global coverage in this review we discuss the principal applications of this dataset to volcano monitoring 1 the detection and tracking of large eruption clouds primarily for aviation hazard mitigation and 2 the use of omi data for long term monitoring of volcanic degassing this latter application is relatively novel and despite showing some promise requires further study into a number of key uncertainties we discuss these uncertainties and illustrate their potential impact on volcano monitoring with omi through four new case studies we also discuss potential future avenues of research using omi data with a particular emphasis on the need for greater integration between various monitoring strategies instruments and datasets

storm driven variability of the beach nearshore profile at duck north carolina usa 1981 1991 the us army corps of engineers field research facility frf at duck north carolina has collected approximately biweekly beach nearshore profile data to 8 m depth and associated wave data since 1981 sediment budget analysis was used to examine the medium scale years to a decade variability of the beach nearshore profile from 1981 to 1991 significant changes occurred during four groups of energetic storm events during february march of 1983 1987 1989 and december 1989 each group was comprised of at least two storms within a period of less than 39 days both with hmo 4 m during each storm group offshore sediment movement caused a distinct outer bar to migrate offshore and grow in size resulting in an abrupt increase in the volume of sediment on the upper shoreface the net profile changes were much larger than the changes due to single storms and the cumulative effect of the storms can be considered as one event during these events the first storm appears to have a destabilizing effect on the profile which has insufficient time to recover before the second and subsequent storm s as a result several storms in quick succession are able to have a large impact on the morphology the intervening periods between the groups of storm events termed fairweather conditions lasted up to 4 years they are characterized by slow but steady sediment redistribution averaging 33 m3 m 1 year 1 from the upper shoreface 5 m depth toward the shore while the total sediment volume was effectively constant the onshore feed of sediment was not significantly affected by individual storms during the fairweather conditions these two processes of 1 morphologic change during groups of storm events and 2 the steady onshore feed of sediments from the shoreface during fairweather conditions appear to play an important role on medium and long term profile evolution at least at duck

coastal flooding from wave overtopping and sea level rise adaptation in the northeastern usa abstract in the northeastern united states flooding arising from wave overtopping poses a constant threat to coastal communities during storm events the purpose of this study is to construct a novel integrated atmosphere ocean coast and overtopping drainage modeling framework based on the coupled tide surge and wave model swan adcirc to assess risk and facilitate coastal adaptation and resilience to flooding in a changing climate in this region the integrated modeling system was validated against the field observations of water level wave height and period during the january 2015 north american blizzard the water level collected by a sensor in the avenues basin behind the seawall in scituate massachusetts were combined with the basin relationship between basin area and water level given by the usgs lidar data to obtain the field measurements of wave overtopping water volume in order to verify the model predictions at the storm peak the significant wave height was increased by 0 7 m at the coast by tide and surge the wave setup along the coast varied from 0 1 m to 0 25 m depending on the coastline geometry the interaction between tide surge and waves increased the wave overtopping rate by five folds mainly due to the increased wave height at the toe of the seawall the wave overtopping discharge would approximately double in an intermediate sea level rise scenario of 0 36 m by 2050 for a storm like the january 2015 north american blizzard the wave overtopping discharge would increase by 1 5 times if the seawall crest elevation was raised by the same amount as sea level rise as an adaptation strategy an increase of 0 9 m in the seawall crest elevation instead of 0 6 m currently planned by the town is required to bring the wave overtopping discharge to the current level under a 0 36 m sea level rise scenario this result is primarily due to larger waves arriving at the seawall without breaking in the presence of larger water depth

palaeomagnetic dating and tectonic significance of dolerite intrusions in the albany mobile belt western australia abstract dolerite dykes and sills in the mesoproterozoic albany mobile belt and neoproterozoic stirling range formation metasediments in southwestern australia provide evidence for extensional events between australia east antarctica and greater india paleomagnetic analysis shows that primary remanence was carried by single domain magnetite for samples from seven localities palaeomagnetic poles for the majority of sites fall close to the earliest cambrian part of the australian apparent polar wander path apwp the interpreted earliest cambrian dykes intrude both extensional dominant and shear fractures indicating nne ssw extension between the western australian and east antarctic shields and a horizontal ese wnw maximum compressive stress dyke emplacement appears to be contemporaneous with mafic volcanism in central and northern australia and igneous intrusion in once contiguous parts of the east antarctic shield these features are interpreted as being related to gondwanaland assembly and may represent a response to far field stresses resulting from the collision between east and west gondwanaland a second suite of nw striking mid carboniferous dykes is related to ne sw extension and rifting between greater india and the western australian shield during early stages in the formation of the perth basin in a sinistral transtensional regime along the southern western australian margin a palaeopole from the primary remanence in a nnw striking dolerite dyke falls on the poorly defined triassic to early cretaceous part of the australian apwp indicating a possible third phase of dyke emplacement regional tectonic constraints for rifting in the perth basin suggest that this youngest dyke most likely intruded during the triassic

storms and shoreline retreat in the southern gulf of st lawrence abstract storms play a major role in shoreline recession on transgressive coasts in the southern gulf of st lawrence gsl southeastern canada long term relative sea level rise off the north shore of prince edward island has averaged 0 3 m century over the past 6000 years 0 2 m century over 2000 years this has driven long term coastal retreat at mean rates 0 5 m a but the variance and details of coastal profile response remain poorly understood despite extensive sandy shores sediment supply is limited and sand is transferred landward into multidecadal to century scale storage in coastal dunes barrier washover deposits and flood tidal delta sinks charlottetown tide gauge records show mean relative sea level rise of 3 2 mm a 0 32 m century since 1911 a further rise of 0 7 0 4 m is projected over the next 100 years when differenced from tidal predictions the water level data provide a 90 year record of storm surge occurrence combined with wind wave hindcast and sea ice data this provides a catalogue of potentially significant coastal storms we also document coastal impacts from three recent storms of great severity in january and october 2000 and november 2001 digital photogrammetry 1935 1990 and shore zone surveys 1989 2001 show large spatial and temporal variance in coastal recession rates weakly correlated with the storm record in part because of wave suppression or coastal protection by sea ice large storms cause rapid erosion from which recovery depends in part on local sand supply but barrier volume may be conserved by washover deposition barrier shores with dunes show high longshore and interdecadal variance with extensive multidecadal healing of former inlet and overwash gaps this reflects recovery from an episode of widespread overwash prior to 1935 possibly initiated by intense storms or groups of storms in the latter half of the 19th century with evidence from the storms of 2000 2001 this points to the importance of storm clustering on scales of weeks to years in determining erosion vulnerability as well as the need for a long term large scale perspective in assessing coastal stability the expected acceleration in relative sea level rise together with projections of increasing storm intensity and greatly diminished winter ice cover in the southern gsl implies a significant increase in coastal erosion hazards in future

linkages between sediment composition wave climate and beach profile variability at multiple timescales the paper analyses compares and contrasts cross shore morphodynamic behaviour of four diverse beaches that have very different regional settings wave climates and sediment characteristics with the aid of rarely available long term measurements of beach profiles and incident waves the beaches investigated are narrabeen beach new south wales australia milford on sea beach christchurch bay uk hasaki coast ibaraki prefecture japan and joetsu ogata coast niigata prefecture japan a statistical analysis equilibrium beach profile analysis and empirical orthogonal function analysis are used to investigate compare and contrast spatial and temporal variability of cross shore beach profiles of the selected beaches at short medium and long term timescales all beaches show evidence of multi timescale morphodynamic change narrabeen beach profile has the highest sensitivity to local weather patterns milford on sea joetsu ogata and hasaki profiles are sensitive to seasonal variation of the wave climate however they also show some correlations with regional climate variabilities the nature of sediment exchange across the profile which contributes to profile shape change with time is found to be related to sediment characteristics across the profile at milford on sea and joetsu ogata both of which have composite profiles sediment exchange between the upper beach and the inter tidal zone dominates profile change irrespective of the distinct differences in sediment composition found in the two beaches on the other hand in narrabeen and hasaki where beach sediment comprises medium to find sand sediment exchange and hence profile change occur mainly in intertidal and subtidal zones

on the cross shore profile change of gravel beaches abstract this paper investigates cross shore profile changes of gravel beaches with particular regard to discussing the tendency for onshore transport and profile steepening in the swash zone the discussion includes observed morphological changes on a gravel beach from experimental investigations at the large wave flume gwk in hanover germany during the tests all the profile changes occurred in the swash zone resulting in erosion below the still water line swl and formation of a berm above the swl we investigate the profile evolution evaluating the transport rates from a bed load sediment transport formulation coupled with velocities calculated from a set of boussinesq equations that have been validated for its use in the surf and swash zones lynett p j wu t r and liu l f p 2002 modelling wave runup with depth integrated equations coastal engineering 46 89 107 otta a k and pedrozo acuna a 2004 swash boundary and cross shore variation of horizontal velocity on a slope in j m smith editor proceedings 29th international conference on coastal engineering world scientific lisbon portugal pp 1616 1628 we discuss the influence of bottom friction on the predicted profiles using reported friction factors from experimental studies it is shown that the use of a different friction factor within a realistic range in each phase of the swash uprush and backwash improves prediction of the beach profiles although quantitative agreement between the measured and computed profile evolutions is not satisfactory furthermore if the friction factor and the transport efficiency c of the sediment transport formulation are kept the same in the uprush and backwash accurate representation of profile evolution is not possible indeed the features of the predicted profiles are reversed however when the c parameter is set larger during the uprush than during the backwash the predicted profiles are closer to the observations differences between the predicted profiles from setting non identical c values and friction factors for the swash phase are believed to be linked to both the infiltration effects on the flow above the beachface and the more accelerated flow in the uprush

possible organisms similar to ediacaran forms from the bhander group vindhyan supergroup late neoproterozoic of india abstract fossil medusoid genera resembling ediacaria sprigg 1947 and hiemalora fedonkin 1982 and having distinctive ediacaran affinity have been discovered in a shale horizon occurring at the base of the bhander group the uppermost unit of the vindhyan supergroup of central india this is the first record of unequivocal occurrence of ediacara like fossils in a proterozoic basin of the peninsular india this finding substantially extends the previously known biogeographic range of the ediacaran elements to peninsular india and further enhances their biostratigraphpic potential for correlation of the upper vindhyans with some ediacaran horizons of canada australia south africa and russian platforms with this extension the representatives of the genus ediacaria can be regarded as having a global distribution in places now occupying both lower and higher latitudes the genus hiemalora which appeared to be endemic to the russian block also has wide biogeographic coverage these fossils assign an ediacaran 550 543 ma age for the host lakheri limestone and suggest that the lakheri unit was deposited within 6 million years of the precambrian cambrian boundary they also support and refine the traditional view of the late neoproterozoic age for the lower bhander group these fossils provide positive stratigraphic clues for locating the precambiran cambrian boundary strata in the overlying lakheri sirbu segment of the vindhyan sequence they also indicate a depositional environment typical of a muddy shallow shelf setting above storm wave base

reconstruction of so2 flux emission chronology from space based measurements abstract infrared satellite images measured with the modis instrument of the volcanic plume produced during the 2006 eruption of mt etna were analysed to produce maps of so 2 amount we used these maps to reconstruct time series of so 2 fluxes by integrating profiles of so 2 orthogonal to the plume advection direction and multiplying with wind speeds from a meteorological model these data were then compared with a reconstructed time series of so 2 fluxes measured with the flame ground based network of ultraviolet doas systems surrounding the volcano we found weak agreement on 3rd december when little ash was emitted but this agreement improved when a 0 3 m s 1 wind speed correction factor was used flame and modis results were in good agreement on the 6th december and improved when a 0 3 m s 1 offset was applied the corrected data revealed that the only period of time when flame and modis did not track together was coincident with the presence of ash which interferes with the ir imagery and retrieval of so 2 we highlight that combining two independent time series of so 2 flux allows a precise determination of wind speed if there is sufficient time dependent structure in the so 2 signal the observed increase in so 2 flux prior to the ash emission is interpreted as a quiescent release of an accumulated gas phase that drive eruptive activity as previously suggested for the southeast crater system of etna in this case the so 2 flux signal therefore acted as a precursor to the eruptive ash events this work demonstrates that quantitative reconstruction of so 2 flux time series is feasible using modis data opening a new frontier in the use of satellite data to interpret volcanic processes in particular in poorly monitored remote locations

first estimate of volcanic so2 budget for vanuatu island arc abstract the spatial and temporal coverage of measurements of volcanic gas emissions remains patchy however over the last decade emissions inventories have improved thanks to new measurements of some of the lesser known volcanic areas we report on one such region the vanuatu island arc in the southwest pacific for which we now have sufficient systematic observations to offer a systematic emissions inventory our new estimate is based on so 2 flux measurements made in the period 2004 2009 with ultraviolet spectroscopy techniques for the following volcanoes yasur lopevi ambrym ambae gaua and vanua lava from south to north these are the first ever measurements for lopevi gaua and vanua lava the results reveal the vanuatu arc as one of earth s prominent sources of volcanic degassing with a characteristic annual emission to the atmosphere of 3 tg of so 2 representing about 20 of hitherto published global estimates our new dataset highlights the sustained prodigious degassing of ambrym volcano whose 5 gg day 1 mean flux of so 2 represents nearly two thirds of the total budget for the vanuatu arc this confirms ambrym as one of the largest volcanic sources worldwide comparable to etna often considered as the most vigorous source of volcanic emission on earth we also report a high degassing for ambae of 2 gg day 1 so 2 representing more than 28 of the vanuatu arc budget thus 90 of the so 2 output from vanuatu is focused in the central part of the arc from ambrym and ambae where magmas originate from enriched indian type mantle and where peculiar tectonic conditions could favor high magma production rates

measuring volcanic degassing of so2 in the lower troposphere with aster band ratios we present a new method for measuring so2 with the data from the aster advanced spaceborne thermal emission and reflectance radiometer orbital sensor the method consists of adjusting the so2 column amount until the ratios of radiance simulated on several aster bands match the observations we present a sensitivity analysis for this method and two case studies the sensitivity analysis shows that the selected band ratios depend much less on atmospheric humidity sulfate aerosols surface altitude and emissivity than the raw radiances measurements with 25 relative precision are achieved but only when the thermal contrast between the plume and the underlying surface is higher than 10 k for the case studies we focused on miyakejima and etna two volcanoes where so2 is measured regularly by cospec or scanning doas the so2 fluxes computed from a series of ten images of miyakejima over the period 2000 2002 is in agreement with the long term trend of measurement for this volcano on etna we compared so2 column amounts measured by aster with those acquired simultaneously by ground based automated scanning doas the column amounts compare quite well providing a more rigorous validation of the method the so2 maps retrieved with aster can provide quantitative insights into the 2d structure of non eruptive volcanic plumes their dispersion and their progressive depletion in so2

laboratory investigation of coastal beach erosion processes under storm waves of slowly varying height abstact storm induced large coastal waves are a predominant driver for coastal erosion problems but the physical processes of storm erosion have not been fully understood due to some technical difficulty in simulating storm waves with timely varying heights in the laboratory and collecting storm beach profiles in the field in this study novel series of experiments are proposed to study sandy beach processes under coastal storm conditions in a laboratory wave flume of 60 m long 3 m wide and 1 5 m high two water depths of h 0 5 m and h 0 7 m were used to investigate beach response under low and high tidal levels two initially uniform plane beach slopes of tan 1 15 for dissipation beach and tan 1 5 for reflection beach were used to study beach profile changes additionally intermediate beach tan 1 10 was also experimentally investigated under regular waves in another wave flume of 30 m long 0 6 m wide and 1 m high non intrusive instrumentation of high resolution cameras was used to record time series photo images on beach profile evolution in spatial resolution of 0 2 cm and a temporal resolution of 0 1 s image analyzing techniques were also developed to transform the recorded photo images to digital data on both beach and water surface profiles in analyzing the collected data it is found that the variation of storm wave height results in changes of wave breaking point and also sediment transport direction before and after the wave breaking point sediment transport direction was found to move onshore initially under small storm waves and then a sand bar was generated and a certain portion of sediment also moved offshore under large waves but such monotonic relationship between sediment transport and wave forcing could transform as morphology feedback and phase lags between wave orbital fluid velocity and sediment concentration the wave energy flux at the breaking point is shown to be suitable parameter in predicting beach mass change or storm erosion rate while the dimensionless sediment settling velocity parameter may not be a suitable criterion for predicting beach erosion or accretion under storm waves

so2 flux from stromboli during the 2007 eruption results from the flame network and traverse measurements abstract so 2 fluxes emitted by stromboli during the 27th february 2nd april 2007 effusive eruption were regularly measured both by an automatic network of scanning ultraviolet spectrometers and by traverse measurements conducted by boat and helicopter the results from both methodologies agree reasonably well providing a validation for the automatic flux calculations produced by the network approximately 22 000 t of so 2 were degassed during the course of the 35 day eruption at an average rate of 620 t per day such a degassing rate is much higher than that normally observed 150 200 t d because the cross sectional area occupied by ascending degassed magma is much greater than normal during the effusion as descending degassed magma that would normally occupy a large volume of the conduit is absent we propose that the hydrostatically controlled magma level within stromboli s conduit is the main control on eruptive activity and that a high effusion rate led to the depressurisation of an intermediate magma reservoir creating a decrease in the magma level until it dropped beneath the eruptive fissure causing the rapid end of the eruption a significant decrease in so 2 flux was observed prior to a paroxysm on 15th march 2007 suggesting that choking of the gas flowing in the conduit may have induced a coalescence event and consequent rapid ascent of gas and magma that produced the explosion

three years of so2 flux measurements of mt etna using an automated uv scanner array comparison with conventional traverses and uncertainties in flux retrieval 1 sviluppo di sistemi di monitoraggio dipartimento di protezione civile della regione sicilia 2 ingv istituto nazionale di geofisica e vulcanologia sezione di catania italy 3 novac network for observation of volcanic and atmospheric change eu funded sixth framework programme project 18354 4 uk nerc national centre for earth observation via the dynamic earth and geo hazards

first synoptic analysis of volcanic degassing in papua new guinea we report the first satellite based survey of volcanic sulphur dioxide so2 degassing in papua new guinea using ozone monitoring instrument omi data omi is sensitive to low level passive degassing these observations are useful for volcano monitoring hazard assessment particularly aviation hazard and assessment of arc geochemical budgets and are of immense value in remote regions with little ground based instrumentation such as papua new guinea we identify bagana manam rabaul ulawun and langila as the active sources of volcanic so2 in papua new guinea with bagana being the largest source we present an omi so2 time series for 2005 2008 and a total detected regional output of 1 8 109 kg so2 about 40 of emissions were released by major eruption events at manam january 2005 bagana june 2006 and rabaul october 2006 over the past century however we estimate that major explosive eruptions contribute 5 of the arc scale so2 emission budget ground based doas measurements of so2 degassing at five of papua new guinea s volcanoes are compared with our omi observations the total omi so2 output is only 20 of the total extrapolated from doas a discrepancy which we demonstrate is consistent with other volcanic arcs therefore the true total regional so2 output may be considerably higher than that detected by omi uncertainties in the omi so2 data include the effects of in plume chemical processing and dilution of so2 prior to the satellite overpass omi s reduced sensitivity to low levels of so2 in the planetary boundary layer and interference by meteorological clouds

satellite and ground observations of the june 2009 eruption of sarychev peak volcano matua island central kuriles after 33 years of repose one of the most active volcanoes of the kurile island arc sarychev peak on matua island in the central kuriles erupted violently on june 11 2009 the eruption lasted 9 days and stands among the largest of recent historical eruptions in the kurile island chain satellite monitoring of the eruption using moderate resolution imaging spectroradiometer meteorological agency multifunctional transport satellite and advanced very high resolution radiometer data indicated at least 23 separate explosions between 11 and 16 june 2009 eruptive clouds reached altitudes of generally 8 16 km above sea level asl and in some cases up to 21 km asl clouds of volcanic ash and gas stretched to the north and northwest up to 1 500 km and to the southeast for more than 3 000 km for the first time in recorded history ash fall occurred on sakhalin island and in the northeast sector of the khabarovsky region russia based on satellite image analysis and reconnaissance field studies in the summer of 2009 the eruption produced explosive tephra deposits with an estimated bulk volume of 0 4 km3 the eruption is considered to have a volcanic explosivity index of 4 because the volcano is remote there was minimal risk to people or infrastructure on the ground aviation transport however was significantly disrupted because of the proximity of air routes to the volcano