frontogenesis subduction and cross front exchange at upper ocean fronts the subduction of water at upper ocean fronts driven by internal instabilities is investigated a simple analytic model which assumes conservation of potential density and potential vorticity is used to characterize the expected structure of subducted parcels as a function of the surface layer depth and the length scale of the parcel parcels subducted from a deep surface layer will be characterized by anomalously low potential vorticity and anticyclonic circulation while shallow surface layers result in subducted parcels with high potential vorticity and cyclonic circulation a nonlinear isopycnal primitive equation model is used to demonstrate how baroclinic instability and the resulting frontogenesis force the subduction of parcels below and across the front frontogenesis generates vertical velocities of 0 30 m d and ageostrophic cross front flows of 3 to 5 cm s the subduction is achieved by the deep ageostrophic flow which carries water from the surface layer below and across the front the subducted parcels quickly develop a circulation through balanced adjustment anticyclonic for deep surface layers and cyclonic for shallow surface layers the characteristics of parcels subducted in winter conditions closely resemble a class of eddies called submesoscale coherent vortices the horizontal and vertical scales of the vortices are determined by the frontogenetic mechanism and the depth of the surface layer the total permanent subduction rate is estimated to be 20 m yr for frontal subduction driven by frontogenesis although local and temporary subduction can be much larger the subducted anticyclonic vortices are often coupled to upper ocean cyclonic vortices thus forming a baroclinic dipole that propagates at approximately 3 5 cm s and is capable of transporting the anomalous water properties far from the region of formation similarities with observations in the north atlantic subtropical convergence zone and near the gulf stream are discussed

estimating exposure around san miguel volcano el salvador abstract san miguel one of the most active volcanoes in el salvador is surrounded by several villages and cantons which could be seriously affected in case of a new eruption this study presents an exposure analysis of the san miguel volcano area by considering population distribution land use private houses official buildings hospitals schools etc and communication infrastructure we use spatial analysis geographic information system tools to estimate exposure for different volcanic hazards air fallout lava flows pyroclastic density currents lahars moreover in the particular case of private houses and official buildings we estimate a vulnerability index for the hazardous areas applying the physical vulnerability methodology based on the characterization of the type of construction materials of walls and roofs we construct different exposure maps for 1 population 2 land use 3 road networks 4 schools and 5 health centers this approach identifies the elements at risk according to each potential hazard thus providing the authorities with a comprehensive tool to better understand the problem and to define emergency plans to minimize risk

a new volcanic management risk database design verdi application to el hierro island canary islands abstract one of the most important issues in modern volcanology is the assessment of volcanic risk which will depend among other factors on both the quantity and quality of the available data and an optimum storage mechanism this will require the design of purpose built databases that take into account data format and availability and afford easy data storage and sharing and will provide for a more complete risk assessment that combines different analyses but avoids any duplication of information data contained in any such database should facilitate spatial and temporal analysis that will 1 produce probabilistic hazard models for future vent opening 2 simulate volcanic hazards and 3 assess their socio economic impact we describe the design of a new spatial database structure verdi volcanic management risk database design which allows different types of data including geological volcanological meteorological monitoring and socio economic information to be manipulated organized and managed the root of the question is to ensure that verdi will serve as a tool for connecting different kinds of data sources gis platforms and modeling applications we present an overview of the database design its components and the attributes that play an important role in the database model the potential of the verdi structure and the possibilities it offers in regard to data organization are here shown through its application on el hierro canary islands the verdi database will provide scientists and decision makers with a useful tool that will assist to conduct volcanic risk assessment and management

the subthermocline lens d1 part i description of water properties and velocity profiles abstract one remarkable result of the local dynamics experiment in polymode is the discovery of a large number of small energetic eddies using ctd data sofar float tracks and profiles of absolute velocity we describe one of these features the subthermocline eddy d1 the feature has an advective time scale of 1 day and its primary mode of movement is advection by the ambient flow field the eddy is resolved into a coordinate system moving with the velocity of the ambient flow which ranges from 11 16 cm s 1 its phase speed is less than 2 cm s 1 the eddy is a lens centered at 1500 db velocity profiles show the lens has no detectable signal in and above the main thermocline or below about 3000 db its subsurface velocity maximum is 28 6 cm s 1 at 1500 db 15 km from the center the radial variation of the azimuthal velocity is gaussian inside the velocity maximum but decays as e br beyond there is little evidence of the eddy beyond a radius of 25 km inside the velocity maximum the eddy is characte

vertical and lateral collapses on tenerife canary islands and other volcanic ocean islands recent studies demonstrate that tenerife has undergone large lateral collapses this has led to the suggestion that the las canadas caldera one of the best exposed calderas in the world is the result of lateral collapse we have tested this idea using the available structural stratigraphic volcanological and geochronological data we conclude that the las canadas caldera is the result of a complex sequence of vertical collapse events associated with a long history of phonolitic explosive activity in the central part of tenerife our results indicate however that vertical collapses may have played a major role in triggering lateral collapses we propose that the association of vertical and lateral collapse events such as inferred for tenerife can also explain similar sequences of events interpreted to have affected other large volcanic ocean islands

warm outbreaks of the gulf stream into the sargasso sea a warm outbreak is a large body of gulf stream water with apparent anticyclonic circulation that detaches from the gulf stream and exists as a well defined entity in the sargasso sea because warm outbreaks are warmer at the surface than sargasso sea water they are often clearly visible in satellite thermal infrared imagery from a survey of over 750 satellite images covering the sargasso sea immediately to the south of the gulf stream between 64 and 74 w and spanning a 5 year period 18 possible outbreaks have been observed all formed west of 65 w with the majority forming between 67 and 72 w five of the 18 were observed to detach completely from the gulf stream and have the following properties in common 1 they all formed in several days at or near the point of maximum cyclonic curvature of a large gulf stream meander 2 the surface expression was relatively short lived of the order of 10 to 20 days and 3 their dimensions and those of the other 13 were of the order of 100 by 200 km given the similarity between the characteristics of warm outbreaks and those of opposite vortices predicted by ikeda and apel 1981 from a two layer quasi geostrophic model of an eastward flowing jet it is suggested that the two phenomena are related further support of this hypothesis is the fact that the rate of formation of warm outbreaks between two and six per year is similar to that of anticyclonic eddies observed in expendable bathythermograph surveys of this area

regional primitive equation studies of the gulf stream meander and ring formation region abstract primitive equation and quasi geostrophic eddy resolving open ocean models are used for hindcast studies in the gulf stream meander and ring formation region a feature model approach is used to initialize the models based on one month of observations during november to december 1984 flat bottom and topographic calculations are carried out using an initial gulf stream velocity profile based on the pegasus dataset all of the major events observed in the upper thermocline are reproduced by both numerical models the addition of bottom topography is shown to significantly alter the character of the deep velocity fields large basin scale circulations found near the bottom in both flat bottom calculations were replaced by energetic jets and eddies associated with the dominant spatial scales of the bottom topography use of the quasi geostrophic model to dynamically adjust the initial conditions for the primitive equation model is shown to reduce the growth of large scale meanders on time scales o

towards a lagrangian description of the gulf stream abstract downstream velocity relative to the axis of the gulf stream is examined through the use of data from sofar floats the speed calculated from the position of the floats along constant pressure surfaces is expressed in terms of a transformed cross stream coordinate given by temperature which is telemetered from the floats the result is a distribution of downstream velocity unaffected by meanders from cape hatteras to 46 w the speed at 700 m is about 75 cm s 1 west of 57 w and decreases sharply to 40 cm s 1 to the east in the deep water from 1300 to 2200 m the core speed is 35 cm s 1 between 65 and 50 w if it is present the flow in the gulf stream may be disturbed by local processes which are frequently observed in satellite imagery examples am shingles ring formation and meanders although sofar floats are quasi lagrangian isobaric devices the float data can give a lagrangian description of the gulf stream above the main thermocline a current coinciding with the tilting isotherms fr

eruptive and structural history of teide volcano and rift zones of tenerife canary islands the teide and pico viejo stratocones and the northwest and northeast rifts are products of the latest eruptive phase of the island of tenerife initiated with the lateral collapse of its northern flank that formed the las canadas caldera and the icod la guancha valley ca 200 ka the eruptive and structural evolution of this volcanic complex has been reconstructed after detailed geological mapping and radioisotopic dating of the significant eruptive events a set of 54 new 14 c and k ar ages provides precise age control of the recent eruptive history of tenerife particularly teide volcano the third highest volcanic feature on earth 3718 m above sea level 7 km high and unique in terms of its intraplate setting the development of the teide pico viejo volcanoes may be related to the activity of the northwest and northeast rifts volcanic and intrusive activity along both rift zones may have played an important role in activating the gravitational landslide and in the subsequent growth nested within the collapse embayment of an increasingly higher central volcano with progressively differentiated magmas the coeval growth of the central volcano with sustained activity along the rifts led to a clear bimodal distribution in composition of eruptive products with the basaltic eruptions in the distal part of the rifts and phonolitic and more explosive eruptions in the central area where the differentiated stratocones developed current volcanic hazard in tenerife is considered to be moderate because eruptive frequency is low explosivity is modest and the eruptive activity of the teide stratocone seems to have declined over the past 30 k y with only one eruption in this period 1150 yr b p

a statistical description of the mean circulation and eddy variability in the northwestern atlantic using sofar floats abstract velocity data obtained from trajectories of sofar floats launched as part of several experiments carried out in the northwest atlantic during the last two decades are used to give a statistical description of the mean gulf stream and its recirculation the distribution of eddy variability in the region is also presented a mean gulf stream which bifurcates between 55 and 45 w to feed the north atlantic current and a southern recirculation can be clearly identified a weak interior sverdrup flow is also suggested the spatial distribution of eddy variability is consistent with previous descriptions showing a maximum near the gulf stream

detection structure and origin of extreme anomalies in a western atlantic oceanographic section abstract ten anomalous water parcels were detected in the water column of a western atlantic oceanographic section 0 5550 m 70 w 23 33 n the parcels had extreme properties lying either two standard deviations from historical mean values or estimated origins lying 2000 km from the oceanographic section detection structure and origin of the parcels were determined from analyses on isobaric and isopycnal surfaces using eight kinds of measurements temperature salinity oxygen light scattering silicate phosphate nitrate and tritium the parcels originated from seven of the major water masses comprising the north atlantic ocean as observed along the oceanographic section the parcels had the following average range characteristics vertical pressure extent 650 db 100 150 db horizontal extent 130 km 30 260 km and distance to origin 2300 km 400 5200 km a population density equaling approximately one parcel per 100 km was obtained as the number of parcels 10 divided by the length o

sedimentology of middle ordovician carbonates in the argentine precordillera evidence of regional relative sea level changes the las aguaditas formation in the argentine precordillera of san juan is the only ordovician carbonate sequence deposited on a slope spiculites mudstones and calcisiltites represent the autochthonous sediments characterized by a fine lamination rare fossils and their dark colour the pelagic fauna consists of rare radiolarians calcispheres trinucleid trilobites graptolites and conodonts the latter are typical of an open marine environment and proved a llanvirn llandeilo age for the las aguaditas formation

mean flow and variabilities in the deep western boundary current abstract the deep western boundary current dwbc or western boundary undercurrent was observed for over 100 days by an l shaped array of current meters along and across the blake escarpment the measurements show a mean southward flow which at its core 10 km east of the break of the escarpment reaches a maximum of 22 cm s 1 at a depth of 2500 m the mean flow decreases to zero at the break and 6 cm s 1 50 km east of the escarpment the core of the current decreases to 15 cm s 1 near the bottom and to zero at 800 m depth the mean southward volume transport is estimated to be 24 106 m3 s 1 24 sv two fluctuations in the southward current with amplitudes of the same order as the mean flow are observed below 200 m these events are consistent with the flow patterns of southward moving anticyclonic features the much reduced current observed might not reflect actual large reductions in the volume transport of the dwbc the array measurements together with a sofar float that got caught in the dwbc do

the structure dynamics and origin of a small scale lens of water in the western north atlantic thermocline abstract a small scale isolated anticyclonically rotating lens of water was observed in the western north atlantic thermocline during the polymode local dynamics experiment using a combination of sofar float hydrographic nutrient and moored current and temperature data we deduce that the lens was about 20 km across with a thickness not greater than 300 m centered on 750 m that its shape was not dissimilar to that of a vertical radial gaussian eddy and that at its center the lens had strong anomalies of salinity dissolved oxygen nitrate and vortex stretching the water mass properties within the eddy are not inconsistent with an origin for the feature near 15 n 54 w several thousand kilometers from where it was observed in the western north atlantic although an unambiguous origin cannot be discerned from the data if such features are not uncommon they may be an important mechanism for large scale mixing of water properties in the ocean

gulf stream flow field and events near 68 w the synoptic ocean prediction synop experiment was designed to provide an accurate understanding of the energetic mesoscale processes in the gulf stream the central array measured velocity and temperature throughout the water column with horizontal extent large enough nearly to span the meander envelope and eulerian mean structure of the jet at 68 w the 55 to 70 km mooring spacing resolved mesoscale eddy interactions with the gulf stream and the 26 month duration allowed stable estimation of long term mean fields six steep meander troughs propagated into or developed within the array each lasting around 30 60 days thus impressing a small mean trough near 68 w in the predominantly eastward currents at jet level 1000 m and above at the deep level 3500m the mean flow was southwest at the shoreward sites shallower than 4300 m but it flowed cyclonically around a mean low pressure anomaly affecting all the deeper offshore sites the eddy kinetic energy per unit mass e k decreased by a factor of about 2 5 with each depth increment from 400 to 700 to 1000 m but was only a factor of 2 smaller at 3500 m than at 1000 m values of e k in the upper central jet 400 m were 100 to 230 mj kg 1 and were 4 13 mj kg 1 at 3500 m overall e k in the upper 1000m at 68 w was higher than previously published values at 55 w two extended case studies of meander propagation through the array demonstrate the development and intensification of deep cyclonic and anticyclonic flows beneath the gulf stream the cyclonic flow at 3500m associated with amplifying meander troughs often exceeded 0 35 ms 1 which was much larger than the typical 0 05 ms 1 deep mean velocities

estimating building exposure and impact to volcanic hazards in icod de los vinos tenerife canary islands abstract principal and subsidiary building structure characteristics and their distribution have been inventoried in icod tenerife canary islands and used to evaluate the vulnerability of individual buildings to three volcanic hazards tephra fallout volcanogenic earthquakes and pyroclastic flows the procedures described in this paper represent a methodological framework for a comprehensive survey of all the buildings at risk in the area around the teide volcano in tenerife such a methodology would need to be implemented for the completion of a comprehensive risk assessment for the populations under threat of explosive eruptions in this area the information presented in the paper is a sample of the necessary data required for the impact estimation and risk assessment exercises that would need to be carried out by emergency managers local authorities and those responsible for recovery and repair in the event of a volcanic eruption the data shows there are micro variations in building stock characteristics that would influence the likely impact of an eruption in the area as an example of the use of this methodology for vulnerability assessment we have applied a deterministic simulation model of a volcanic eruption from teide volcano and its associated ash fallout which when combined with the vulnerability data collected allows us to obtain the vulnerability map of the studied area this map is obtained by performing spatial analysis with a geographical information system gis this vulnerability analysis is included in the framework of an automatic information system specifically developed for hazard assessment and risk management on tenerife but which can be also applied to other volcanic areas the work presented is part of the eu funded exploris project explosive eruption risk and decision support for eu populations threatened by volcanoes evr1 2001 00047

assessing the potential for future explosive activity from teide pico viejo stratovolcanoes tenerife canary islands abstract since the onset of their eruptive activity within the canadas caldera about 180 ka ago teide pico viejo stratovolcanoes have mainly produced lava flow eruptions of basaltic to phonoltic magmas the products from these eruptions partially fill the caldera and the adjacent icod and la orotava valleys to the north although less frequent explosive eruptions have also occurred at these composite volcanoes in order to assess the possible evolution teide pico viejo stratovolcanoes and their potential for future explosive activity we have analysed their recent volcanic history assuming that similar episodes have the highest probability of occurrence in the near future explosive activity during the last 35000 years has been associated with the eruption of both mafic basalts tephro phonolites and felsic phono tephrites and phonolites magmas and has included strombolian violent strombolian and sub plinian magmatic eruptions as well as phreatomagmatic eruptions of mafic magmas explosive eruptions have occurred both from central and flank vents ranging in size from 0 001 to 0 1 km3 for the mafic eruptions and from 0 01 to 20 km3 dre eruptions of phonolitic magmas while teide pico viejo is dominated by effusive eruptions these differences can be explained in terms of the different degree of evolution of teide pico viejo compared to the preceding cycles and consequently in the different pre eruptive conditions of the corresponding phonolitic magmas a clear interaction between the basaltic and phonolitic systems is observed from the products of phonolitic eruptions indicating that basaltic magmatism is the driving force of the phonolitic eruptive activity the magmatic evolution of teide pico viejo stratovolcanoes will continue in the future with a probably tendency to produce a major volume of phonolitic magmas with an increasing explosive potential therefore the explosive potential of teide pico viejo cannot be neglected and should be considered in hazard assessment on tenerife

morphological and geological aspects related to large slope failures on oceanic islands the huge la orotava landslides on tenerife canary islands huge volcanic landslides are one of the most hazardous geomorphological processes that can occur during the evolution of volcanic ocean islands the causes of these phenomena however are very complex and combine non volcanic and volcanic factors in the canary islands more than 20 events have been detected during the last decades a detailed analysis was carried out for la orotava amphitheatre on tenerife in order to understand the relationship between geomorphological and geological aspects and huge volcanic landslides the results indicated four major features that play a significant role in such mass movements deep erosive canyons high coastal cliffs widespread residual soils and structural axes high coastal cliffs and deep erosive canyons locally reduce the stability conditions and control both the seaward and the lateral boundary of the landslide weak residual soils formed above phonolitic pyroclastic deposits occur repeatedly in the stratigraphic column of la orotava and are characterised by their large extent thus one of these soils may have evolved into the slip surface of the failure part of the head scarp of the amphitheatre is defined by a volcanic rift zone as indicated by the measurement of dike orientation and a density map of eruptive vents the four features are not able to trigger a failure but to destabilise the volcano flank and determine the boundary of the slide therefore information on depth and orientation of canyons location and height of coastal cliffs stratigraphic repetition extension and thickness of residual soils and orientation and density of dikes and eruptive vents along structural axes should be incorporated into a hazard assessment on large landslides on volcanic islands

observations of an anticyclonic eddy of 18 c water in the sargasso sea abstract observations have been made of a lens of 18 c water in the sargasso sea near 30 n 69 w the lens was nearly isothermal and isohaline and was embedded in the more typical weakly stratified 18 c water in the area it was more than 500 m thick and 170 km in diameter the lens was moving south southwest at 3 8 km day 1 and was rotating anticyclonically with speeds up to 50 cm s 1 a smaller lens of water near 16 c was located concentrically below the major eddy the 14 c isotherm in the main thermocline was depressed 300 m below its level in the surrounding area and the 20 c isotherm in the seasonal thermocline was raised 50 m significant anticyclonic flow occurred as deep as 850 m in the thermocline these observations confirm previous sparse evidence of eddies of this type it has been suggested that they are generated near the corner rise seamounts we speculate that the observed feature is the remnant of an eddy formed by a convection cell of 18 c water possibly generated near the new england

the spatial and temporal evolution of a cluster of sofar floats in the polymode local dynamics experiment lde abstract up to forty neutrally buoyant floats 20 at 700 m 20 at 1300 m were used in the polymode local dynamics experiment lde to provide a quasi lagrangian description of the structure and evolution of the mesoscale eddy field in a limited region characterized by higher kinetic energy levels than those obtained in mode this paper is an overview and summary of the data collected the temporal development of the two level float array is presented in a sequence of maps each spanning five days in these one readily notices an oscillation of floats at 1300 m in a ne sw direction before the cluster breaks apart at 700 m the float cluster subdivides much more rapidly the first setting of 700 m floats drifts to the west the second group launched two months later goes far to the east ensemble averages as a function of time of the floats at 1300 m reveal great sensitivity to the oscillatory velocity field while the array is tight or coherent the corresponding 700 in averages although noisy sho

a lagrangian based approach for determining trajectories taxonomy and turbulence regimes abstract the use of the ratio between the acceleration and velocity time scales y ta t to separate lagrangian trajectories in homogeneous classes is proposed in fact when analyzing subsurface floats data in the atlantic ocean and surface drifters data in the world s ocean basins it is observed that trajectories having different values of y are characterized by different shapes correlation and dispersal properties in particular trajectories having similar values of the acceleration and velocity time scales clearly show the influence of eddies and are characterized by an oscillating velocity correlation function it is shown here that this trajectory screening is a useful procedure to rationalize the analysis of real lagrangian trajectories and to avoid a mixture of different regimes when averaging quantities the mean statistical quantities computed averaging on quasi homogeneous datasets put in evidence the role of the coherent structures in the dispersion properties both in time and in the ma

the west spitsbergen current as seen by sofar floats during the arctemiz 88 experiment statistics differential kinematic properties and potential vorticity balance sofar floats were launched at 300 m depth in the west spitsbergen current wsc in september 1988 this lagrangian data set is used to compute statistical parameters to produce local maps of mean velocity kinetic energy and eddy kinetic energy and to study dispersion and diffusion in the wsc despite the limited number of float trajectories the values obtained for the diffusivities order 1 0 x 10 7 cm 2 s 1 are close to those found in other regions of the atlantic ocean the molinari and kirwan 1975 method is used to compute the differential kinematic properties divergence vorticity shear and stretching the conservation of potential vorticity in the region of the yermak plateau is not correctly verified this is mainly due to the jet structure of the wsc and the shape of the cluster leading to a biased estimate of the relative vorticity however the results based only on five float trajectories over 30 days are encouraging and not inconsistent with the properties of the west spitsbergen current the existence of a new eastward branch of the wsc passing just over the top of the yermak plateau is confirmed

insight into vent opening probability in volcanic calderas in the light of a sill intrusion model the aim of this paper is to discuss a novel approach to provide insights on the probability of vent opening in calderas using a dynamic model of sill intrusion the evolution of the stress field is the main factor that controls the vent opening processes in volcanic calderas on the basis of previous studies we think that the intrusion of sills is one of the most common mechanism governing caldera unrest therefore we have investigated the spatial and temporal evolution of the stress field due to the emplacement of a sill at shallow depth to provide insight on vent opening probability we carried out several numerical experiments by using a physical model to assess the role of the magma properties viscosity host rock characteristics young s modulus and thickness and dynamics of the intrusion process mass flow rate in controlling the stress field our experiments highlight that high magma viscosity produces larger stress values while low magma viscosity leads to lower stresses and favors the radial spreading of the sill also high rock young s modulus gives high stress intensity whereas low values of young s modulus produce a dramatic reduction of the stress associated with the intrusive process the maximum intensity of tensile stress is concentrated at the front of the sill and propagates radially with it over time in our simulations we find that maximum values of tensile stress occur in ring shaped areas with radius ranging between 350 m and 2500 m from the injection point depending on the model parameters the probability of vent opening is higher in these areas

the las canadas caldera tenerife canary islands an overlapping collapse caldera generated by magma chamber migration abstract the las canadas caldera is one of the most important geological structures of tenerife stratigraphic structural volcanological petrological geochronological and geophysical data suggest that the las canadas caldera resulted from multiple vertical collapse episodes that occurred during the construction of the las canadas edifice upper group three long term 200 ka cycles of phonolitic explosive activity each culminating with a caldera collapse have been identified in the upper group during the construction of the upper group the focus of felsic volcanism migrated from west to east using the results of field observations experimental analogue models and numerical studies we propose that the formation of the overlapping las canadas collapse caldera is related to the migration of the associated magma chamber our model implies that each collapse of this overlapping caldera partly or completely destroyed the feeding magma chamber this destruction led to changes in the local stress field that favoured the formation of a new chamber at one side of the previous one resulting in magma chamber migration the proposed model accounts for the formation of the las canadas caldera in particular it explains the geometrical relationships stratigraphy and chronology of the caldera wall deposits comparison with other overlapping collapse calderas suggests that our model may apply to other overlapping calderas

potential impacts of tephra fallout from a large scale explosive eruption at sakurajima volcano japan we present an exposure analysis of infrastructure and lifeline to tephra fallout for a future large scale explosive eruption of sakurajima volcano an eruption scenario is identified based on the field characterization of the last subplinian eruption at sakurajima and a review of reports of the eruptions that occurred in the past six centuries a scenario based probabilistic hazard assessment is performed using the tephra2 model considering various eruption durations to reflect complex eruptive sequences of all considered reference eruptions a quantitative exposure analysis of infrastructures and lifelines is presented primarily using open access data the post event impact assessment of magill et al earth planets space 65 677 698 2013 after the 2011 vei 2 eruption of shinmoedake is used to discuss the vulnerability and the resilience of infrastructures during a future large eruption of sakurajima results indicate a main eastward dispersal with longer eruption durations increasing the probability of tephra accumulation in proximal areas and reducing it in distal areas the exposure analysis reveals that 2300 km of road network 18 km2 of urban area and 306 km2 of agricultural land have a 50 probability of being affected by an accumulation of tephra of 1 kg m2 a simple qualitative exposure analysis suggests that the municipalities of kagoshima kanoya and tarumizu are the most likely to suffer impacts finally the 2011 vei 2 eruption of shinmoedake demonstrated that the already implemented mitigation strategies have increased resilience and improved recovery of affected infrastructures nevertheless the extent to which these mitigation actions will perform during the vei 4 eruption presented here is unclear and our hazard assessment points to possible damages on the sakurajima peninsula and the neighboring municipality of tarumizu

small water property transporting eddies statistical outliers in the hydrographic data of the polymode local dynamics experiment abstract hydrographic measurements from the polymode local dynamics experiment lde 31 n 69 5 w may july 1978 are examined for highly anomalous outlying observations of salinity oxygen and vortex stretching on isopycnal surfaces the methodology which defines outliers in the observations is based on examination of gaps in histograms of these water properties on each isopycnal these outliers are indicative of vertically confined over 20 2000 m sub mesoscale eddies diameters of 25 50 km at the lde site evidence for 31 eddies is found at the lde site over the two months of the experiment these features are described individually and characterized by their core water properly signal and dynamical structure eighteen features are found to be anticyclonic lenslike structure eight have no detectable dynamic signal and only four are characterized by cyclonic circulation the work establishes that sub mesoscale eddies in a small portion of the western north atlantic exhibit a variety of distinct wat

two years in the life of a mediterranean salt lens abstract a lens of mediterranean water meddy was tracked in the eastern north atlantic for two years with sofar floats the meddy was first found between the canary islands and the azores in october 1984 it center moved in an irregular pattern at speeds of a few cm s 1 and translated 1100 km to the south in two years this meddy was surveyed four times by ctd and velocity profilers and once with the microstructure profiler epsonde when observed during the first two surveys the meddy had a core that was stably and smoothly stratified in both salinity and temperature nearly uniform in the horizontal and was saltier than the surrounding ocean by 0 65 psu the meddy was eroded from its edges top and bottom and lost salt and hat with an e folding time of about one year the salinity at the center remained at its original value during the first year and decreased during the second year evidence was seen for mixing by lateral intrusions double diffusion and turbulence the intrusions are thought to

a coupled model for dispersal of tephra during sustained explosive eruptions abstract we present a model for fallout of tephra based on approximate analytical solutions of the advection diffusion transport equation as usual the model requires the distribution of mass throughout the eruptive column as a boundary condition an input which is normally imposed ad hoc by means of analytical expressions we propose an alternative way to assess this input based on coupling the model of fallout with already existing simple models for volcanic plumes flow along the volcanic conduit and magma chamber withdrawal the final outcome is a one way coupled model that involves all the spatial domains simultaneously and has a good compromise between physical accuracy and computational efficiency the coupled model outputs not only maps of isopachs but also several relevant eruptive parameters such as column height mass eruption rate or duration of the eruption time dependency is introduced via a quasi steady approach that is considering a succession of steady states we apply the model to simulate the 2 ka subplinian eruption of montana blanca tenerife island

stratigraphy structure and volcanic evolution of the pico teide pico viejo formation tenerife canary islands abstract the structure and volcanic stratigraphy of the pico teide pico viejo pt pv formation deriving from the basanite phonolite stratovolcanoes pt and pv and numerous flank vent systems are documented in detail based on new field and photogeologic mapping geomorphologic analysis borehole data and petrological and geochemical findings results provide insight into the structure and evolution of the pt pv magma system and the long term cyclic evolution of tenerife s post shield volcanic complex the pt pv formation comprises products of central volcanism mainly emplaced into the las canadas caldera lcc and contemporaneous products from adjacent rifts pt pv central volcanic products become more differentiated up section with felsic lavas dominating the recent output of the system this is attributed to the evolution of a shallow magma reservoir beneath pt that was emplaced early in the pt pv cycle on the intra caldera segment of tenerife s post shield rift system the rift axis has been the focus of pt pv intrusive and eruptive activity and has controlled the location of the stratocones the current geometry of the rifts reflects a major structural reorganisation defining the start of the pt pv cycle at 0 18 ma namely the truncation of the north side of the lcc lce by the giant icod landslide the internal stratigraphy of the pt pv formation suggests that pt developed early with pv developing as a satellite vent activity has since alternated between pt and pv due to episodes of vent blockage or chamber sealing these processes have allowed significant volumes of phonolitic magmas to develop and accumulate within the pt chamber which have vented through radial dike systems during tumescence episodes and from the rift system which has permitted lateral magma transport the pt pv magma system is a potentially hazardous source of future felsic eruptive activity on tenerife

reconstructed mediterranean salt lens trajectories the existence of energetic anticyclonic mid depth vortices of mediterranean water meddies questions the validity of a conventional advective diffusive balance in the eastern atlantic subtropical gyre a mesoscale experiment in the azores madeira region reveals a link of these meddies to large scale subsurface meanders for the first time it is shown that meddies may have strong surface vorticity indicative of a generation process involving the azores current a deep reaching near surface jet

north atlantic subtropical gyre sofar floats tracked by moored listening stations in 1980 sofar sound fixing and ranging floats were tracked acoustically in the western north atlantic entirely by means of moored autonomous listening stations during a 5 month period 17 float trajectories were obtained in the eastern 45 degrees to 65 degrees w gulf stream and subtropical gyre interior at depths of 700 and 2000 meters these mid depth trajectories suggest a time varying gulf stream with instances of both a narrow swift westward recirculation south of the stream and a northeastward penetration into the newfoundland basin a hundredfold increase of eddy kinetic energy was observed at 2000 meters from the gyre interior south of 30 degrees n to the gulf stream

mesoscale eddy characteristics in the interior subtropical southeast indian ocean tracked from the leeuwin current system abstract two oppositely rotating mesoscale eddies originating from the leeuwin current were captured during a research cruise in the interior southeast indian ocean in august 2012 a few hundred kilometers off the west coast of australia the two eddies had different vertical structures the anticyclonic eddy had stronger vertical shear above 200 m and a less stratified thermocline below the mixed layer while the cyclonic eddy had a more barotropic structure in the upper 500 m compared with the same types of eddies sampled in 2003 close to the australian coast the 2012 anticyclonic eddy had a larger radius deeper isothermal depths and higher peak velocity whereas the 2012 cyclonic eddy had a similar structure with the 2003 survey we use an argo float and three surface drifters deployed and trapped in the anticyclonic eddy to track its evolution over a 4 month period the eddy was observed to propagate 1000 km further to the west indicating that the leeuwin current properties of the eddy may be preserved for over 2000 km off the west coast of australia the eddy appeared to have experienced radial excursions relative to the eddy center with periodicity of 4 6 days and 15 days during their anticlockwise motions the radial movements of the drifters appeared to be constrained by the radial momentum balance within the eddy the importance of eddy distortions to ocean primary production in anticyclonic eddies in the southeast indian ocean warrants further studies

rossby wave radiation in the cape verde frontal zone abstract radiating baroclinic rossby waves excited through instability of the cape verde frontal zone are proposed as a mechanism for the generation of mesoscale variability at middepth 1000 m in the southeastern north atlantic basin linear quasigeostrophic theory is applied to an idealized front representative of the cape verde frontal zone to demonstrate that the front is unstable to modes that may radiate away from the frontal region as baroclinic rossby waves evidence for the existence of these waves is obtained from an eddy resolving basin scale general circulation primitive equation model in addition the model fields are used to identify characteristic signature of the waves in terms of quantities that may be directly observed in the ocean lagrangian trajectories reynolds stress eddy kinetic energy and frequency spectra taken from sofar float and current meter records are all in good agreement with the amplitude and distribution implied by the wave radiation in both the linear theory and

seismic hazard of volcanic activity abstract seismic activity is a common feature of volcanic eruptions the majority of volcanic earthquakes are small their magnitudes do not exceed 2 or 3 at the same time significant moderate size and large volcanic earthquakes may also occur the study of 28 significant m w 4 5 earthquakes associated with volcanic eruptions of 20th century allowed us to formulate the following results about seismic hazard of volcanic activity 1 during the 20th century only three large m w 7 0 earthquakes directly associated with volcanic eruptions in the world were recorded 2 the maximum magnitude m w was estimated to be 5 4 for earthquakes related to central eruptions 7 0 for caldera collapse 5 9 for central eruptions accompanied by flank and or fissure eruptions 7 1 for flank and or fissure eruptions without central eruptions and 5 9 for submarine eruptions for seismicity just before the eruption the maximum magnitude of earthquakes was estimated to be m w 7 1 for seismicity at the initial stage of eruption m w 7 0 for paroxysmal stage of eruption m w 5 6 and for final stage of eruption m w 6 1 3 it was shown that the recurrence time of eruptions of the same type of volcano associated with significant m w 4 5 earthquakes was more than 100 years for 86 of events studied

on the origin of eddies discovered during the polymode local dynamics experiment abstract the intensive hydrographic survey conducted in 1978 as part of the polymode local dynamics experiment lde revealed a large number of anomalous water parcels at various depths near 31 n 70 w in the sargasso sea from analyses of the mean water properties in the lde survey lindstrom and taft have prepared a census of discrete features that have statistically significant anomalies of salinity oxygen or potential vorticity the present analysis utilizes the climatological annual mean north atlantic dataset compiled by levitus to identify the large scale distribution of salinity and oxygen on specific potential density surfaces this technique has revealed distinct geographic origins for the majority of the 23 lde features analyzed nine shallow features residing between 25 8 and 26 4 sigma theta were found to have varied origins two from the eastern atlantic three from the gulf stream two from the central sargasso sea and two were indeterminate with the available data four of six upper th

a preliminary exploration of the gulf stream system with sofar floats abstract sofar sound fixing and ranging floats deployed for engineering tests during 1977 79 yield the first long term quasi lagrangian observations in the subsurface gulf stream system the character of these float tracks supports the premise that the gulf stream is a persistent large scale vertically coherent jet at depths approximately within and above the main thermocline where mean and eddy kinetic energies are roughly the same and lateral motions of the stream are clearly delineated a float track at thermocline depth is visually coherent with the track of a concurrently launched surface drifter over the larger horizontal scales traversed during the first few months of their trajectories below thermocline depths fluctuation or eddy kinetic energies are normally larger than the mean and a persistent gulf stream is difficult to detect however deep motions that are visually coherent with upper level flows may be observed for an intermediate range of space and time scales eddy kinetic energi

surface circulation in the eastern north atlantic from drifters and altimetry a description of the near surface circulation and its properties is the result of the analysis of a drifting buoy data set in the eastern north atlantic between the iberian peninsula the azores and the canary islands world ocean circulation experiment tropical ocean global atmosphere experiment drifters equipped with holey sock drogues centered at 15 m depth collected a total of 14 4 years of data the drifters sampled a rather inhomogeneous velocity field with a weak mean flow regime and eddies of different scales they meandered southward everywhere in the study region except in the iberian coastal transition zone north of 41degreesn where they headed northward the near surface mean velocity field obtained from the drifter data set shows all important mean currents including the poleward portugal coastal countercurrent during the fall winter and early spring off western and northern iberia the southward portugal coastal current the slow offshore southward flow of the portugal current during the whole year the southwestward canary current and the eastward azores current which extends to the vicinity of the african coast near the gulf of cadiz maps of the eddy kinetic energy field were obtained from the drifters and from satellite altimetry it provides the largest part of the total kinetic energy the rate of dispersion is estimated from the lagrangian statistics of the drifting buoys the dispersion of the drifters in the study region is well modeled by a simple description of eddy diffusion assuming homogeneous turbulence ensemble mean diffusivities k and the langrangian integral length scales and timescales l and t were obtained for the zonal and meridional directions the sea surface temperature measured along the drifter trajectories is used to produce estimates of the eddy diffusivity which is compared with the diffusivity estimates obtained from the theory of taylor the eddy diffusivity is found to be approximately proportional to the eddy kinetic energy discrete eddies and meanders were observed using drifters and altimetry in order to map and describe their geographical distribution and characteristics in the eastern north atlantic

westward motion of mesoscale eddies abstract since the pioneering work of nof the determination of the westward drift of mesoscale eddies under the planetary beta effect has been a recurrent theme in mesoscale oceanography and several different formulae have been proposed in the literature here recpatiulation is sought and within the confines of a single layer model a generalized formula is derived although it is similar to nof s the present formula is established from a modified definition and with fewer assumptions it also recaptiulates all other formulae for the one layer model and applies to a wide variety of situations including cases when the vortex develops a wake of rossby waves or undergoes axismmetrization following the derivation of the formula a physical interpretation clarifies the migration mechanism which can be divided between a self induced propulsion and a reaction from the displaced ambient fluid numerical simulations with primitive and geostrophic equations validate the formula for a variety of length sc

tracking three meddies with sofar floats abstract three meddies were tracked for up to two years in the canary basin using neutrally buoyant sofar floats these meddies have cores of warm salty mediterranean water and are approximately 100 km in diameter 800 m thick and are centered at a depth of 1100 m meddy 1 was tracked for two years 1984 86 with five floats as it drifted 1090 km southward with a mean velocity of 1 8 cm s 1 four shipboard surveys made during these two years revealed the nearly total decay of meddy 1 by gradual mixing processes meddy 2 drifted 530 km southwestward over 8 5 months with a mean velocity of 2 3 cm s 1 until it collided with hyeres seamount near 31 n 29 w the floats trapped in this meddy then stopped looping abruptly implying a major disruption of this meddy meddy 3 drifted 500 km southwestward for a year and a half with a mean translation velocity of 1 1 cm s 1 a comparison of the velocity of meddies to the velocity of nearby floats at 1100 m depth outside of the meddies shows clearly that all three m

a synoptic and statistical description of the gulf stream and subtropical gyre using sofar floats abstract trajectories of 17 sofar floats ballasted to nominal depth of 700 and 2000 m and tracked for 15 months have been analyzed to produce synoptic and statistical descriptions of the gulf stream and subtropical gyre sofar floats launched in and near the gulf stream along with positions of the surface gulf stream and satellite tracked buoys demonstrate strong baroclinic shear nevertheless the horizontal patterns of the gulf stream meanders and gulf stream rings are the same at the surface and at 700 and 2000 m depth above the thermocline particle speeds greater than the propagation speed of the meanders cause parcels of water to move with the flow pattern at greater depths the velocities are at most equal to the propagation speed and the deep trajectories are free to pass through the gulf stream or ring strong temporal variability is found near the tail of the grand banks instances of flow both southward into a narrow gulf stream recirculation and northward into the north atlantic current can

analysis of risk assessment factors of individuals in volcanic hazards review of the last decade abstract there are many methods and scientific research approaches where modeling and understanding on how individuals evaluate natural origin risks despite the proficiency and depth of such studies we evidenced a lack for a holistic approach where the most influencing factors in the individual decision making process were covered this research seeks to understand what those factors are how they relate to each other and how the behave with respect to individual perception and acceptance of risk for this we performed a thorough literature review covering the last decade in relation with the understanding of how these incidence factors affected the perception and acceptance of risk in the communities exposed to volcanic events under the decision making process our research was able to detect how the identified variables influenced each other in this process we analyzed different study cases found in the literature and additionally we propose as a further research a new theoretical approach related to decision making modeling process under dynamic system that would be valuable as a contribution to risk management

compact intrathermocline eddies in the sargasso sea we report observations of isolated lenses of constant temperature water embedded in the permanent thermocline in the sargasso sea these features are observed to have vertical extents of 220 m horizontal dimensions of 65 km and residence depths near 700 m a dynamic model is constructed which permits a balance among the pressure gradient coriolis and cyclostrophic forces and maintains the lens against gravitational collapse a result is that anticyclonic rim velocities approaching 20 cm s 1 are permitted and that these eddies have finite radii of the order of 50 km at which their thicknesses fall to zero

covariation of mesoscale ocean color and sea surface temperature patterns in the sargasso sea during the lifetime of the coastal zone color scanner there were 21 instances in which both satellite derived ocean color and sea surface temperature are simultaneously available over large areas of the sargasso sea these images reveal close correspondence between mesoscale structures observed in temperature and pigment fields in general higher lower pigment biomass occurs in mesoscale features consisting of cold warm temperature anomalies this relationship is consistent with the idea that upward displacement of isopycnals at the base of the euphotic zone by mesoscale eddies is an important mechanism of nutrient supply in the region

physical oceanography of the azores front abstract there is a considerable body of evidence for the existence of a permanent front sw of the azores surveys in the summer of 1981 show the structure to penetrate to a depth of 2 000 m and suggest that its meandering is related to the alignment of the atlantis gt meteor seamount chain the total volume transport above 2 000 m is between 10 and 12 106 m3 s 1 towards the east the main water mass contrasts across the front are confined to the upper 400 m of the water column only a small change in mediterranean water strength was seen across the front satellite tracked drogued buoys seeded into the front showed surface speeds of up to 40 cm sec 1 and revealed the formation of a closed cold core eddy some 100 115 km in diameter which propagated westward at 2 2 km day 1 over a 200 day period sea surface temperature contrasts across the frontal boundary are small and together with frequent cloud cover prevent the detection of the front and associated eddies by satellite infra red imagery the front apparently marks the eastward extension of the southern branch of the gulf stream recirculation and the northern limit of the 18 c water mass eddies formed at the front could propagate westward into the interior of the sargasso sea but have not yet been observed to cross the mid atlantic ridge

western boundary current structure and variability east of abaco bahamas at 26 5 n abstract during april 1987 to june 1988 a four mooring transport resolving current meter array was deployed in a section extending 70 km eastward from abaco bahamas at 26 5 n mean currents in the upper layer 800 m showed a clockwise rotation that appears to be associated with a small scale quasi permanent anticyclonic gyre centered just northeast or the bahamas deep mean currents were persistenly southward and indicated a strong deep jet the deep western boundary current dwbc reaching core speeds of 20 cm s 1at 2500 m depth about 25 km seaward of the western boundary vertically integrated meridional volume transport over the section showed a surprisingly large variability ranging from approximately 20 sv northward to 70 sv southward 1 sv 106m3s 1 the mean meridional volume transport was 30 sv to the south with about 3 sv flowing northward above 800 m which could be produced by a weak antilles current and 33 sv flowing southward below 800 m the deep southward transport of 33 sv i

cyclonic activity in the eastern gulf of mexico characterization from along track altimetry and in situ drifter trajectories abstract the shedding sequence of the loop current lc inside the gulf of mexico gom is strongly influenced by cyclonic frontal eddies around its edge along track altimetry data analyzed based on a wavelet decomposition to provide estimates of individual cyclones diameter amplitude and relative vorticity and in situ surface drifter data from the global drifter program are used to investigate the cyclonic activity in the eastern gulf of mexico where the lc extends and retracts by analyzing this 20 year long 1992 2011 combined set of observation data records we were able to complement previous findings to confirm results from modeling studies and to provide new insights on the lc frontal dynamics drifter data indicate for the first time that loop current frontal eddies lcfes are in solid body rotation close to their core this property makes relative vorticity the most robust diagnostic from along track altimetry for characterizing lcfes in the eastern gom based on consistent comparisons with drifter data both data sets are complementary for describing the lcfes regional variability lcfes observed in the deep southeastern gom show intense relative vorticity but they are not frequently observed the study of an unprecedented long drifter trajectory suggests that they are not intensified locally this implies that among lcfes coming from the northern gom only intense ones reach the deep southeastern gom the observation datasets provide for the first time quantitative evidences of processes so far only identified with models lcfes are intensified when they are advected over the mississippi fan in the northern gom a small area north of campeche bank shows intense lcfe activity the altimetry and drifter data confirm and complement results from more limited datasets lcfes forming the tortugas eddies at the entrance of the straits of florida are the most intensely observed lcfes in altimetry coming from the gom interior they can be modified in size and intensity just before or during their stay in the dry tortugas area whereas they were long considered to be modified only after they were advected in the straits of florida a single drifter trajectory illustrates in detail the erosion of a lcfe in the southeastern gom presumably under the influence of the lc which leads to the re arrangement of vorticity and the formation of a distinct lcfe just upstream the dry tortugas area the study also confirms that lcfes have diameters of 80 120 km generally larger east and north of the lc they tend to stay for long periods in the northeastern gom and thus may undergo vortex merging with incoming eddies as previously noted on individual episodes altimetry reveals that the largest lcfes reside in the central eastern gom in a location where they are known to block the lc extension however our long altimetry dataset shows that these large eddies are not always involved in such lc blocking finally this study led to improvements in data treatment for both along track altimetry and drifter trajectories the wavelet approach used to derive eddy characteristics from along track altimetry allows robust estimates of the eddy relative vorticity the drifter dataset has been extended to include data from drifters even after they lost their drogue the latter data treatment can be applied in areas of moderate winds

mixed layer lateral eddy fluxes mediated by air sea interaction abstract the modulation of air sea heat fluxes by geostrophic eddies due to the stirring of temperature at the sea surface is discussed and quantified it is argued that the damping of eddy temperature variance by such air sea fluxes enhances the dissipation of surface temperature fields depending on the time scale of damping relative to that of the eddying motions surface eddy diffusivities can be significantly enhanced over interior values the issues are explored and quantified in a controlled setting by driving a tracer field a proxy for sea surface temperature with surface altimetric observations in the antarctic circumpolar current acc of the southern ocean a new tracer based diagnostic of eddy diffusivity is introduced which is related to the nakamura effective diffusivity using this the mixed layer lateral eddy diffusivities associated with i eddy stirring and small scale mixing and ii surface damping by air sea interaction is quantified in the acc a diffusivity associated with su

a census of eddies observed in north atlantic sofar float data abstract sofar floats that looped in discrete eddies were studied in order to map and describe the distribution and characteristics of eddies in the north atlantic one hundred eighteen individual looping float trajectories loopers were identified each consisting of two or more consecutive loops each looper was interpreted to be in a discrete eddy and its characteristics were estimated from the float trajectory the highest percentage of loopers occured at 700m in the newfoundland basin where roughly half of the float data were in loopers mostly cyclones in the gulf stream region approximately 20 of the float data recorded at 700m were in loopers again mostly cyclones overall 21 of 700m data and 6 of 2000m data were in loopers the fastest swirl speeds 40cm s 1 were in cyclones south of the gulf stream most of which were in gulf stream rings but numerous swift 35cm s 1 anticyclones were found there too swirl velocity decreased with depth to roughly half as swift at 2000m as at 700m for three eddies in the sargasso sea measured simultaneously with floats at these two depths in the western north atlantic the average swirl velocity of cyclones and anticyclones was the same translation velocity of eddies was generally westward to southwestward at a few cm s 1 the mean translation velocity of 39 eddies in the sargasso sea was u bar 2 8 0 4 cm s 1 v bar 0 4 0 4 cm s 1 many of these were located just south of the gulf stream in the region of its recirculation and were probably advected by a westward current there near the gulf stream and along its extension in the newfoundland basin eddies were often advected downstream with speeds up to 15 20cm s 1 and eddy trajectories were often complicated south of 30 n and near the western boundary 700m eddies were advected northwestward and 1300m and 2000m eddies southeastward by boundary currents there numerous energetic anticyclones were observed south of the gulf stream one was tracked for 430 days and its properties well measured the formation of these eddies has not been documented but they are inferred to have formed near and by the gulf stream and to consist of a thick layer of 18 c water lying above a depression in the thermocline analogous anticyclones were observed in the newfoundland basin seaward of the gulf stream extension there

volcanic risk assessment quantifying physical vulnerability in the built environment abstract this paper presents structured and cost effective methods for assessing the physical vulnerability of at risk communities to the range of volcanic hazards developed as part of the mia vita project 2009 2012 an initial assessment of building and infrastructure vulnerability has been carried out for a set of broadly defined building types and infrastructure categories with the likelihood of damage considered separately for projectile impact ash fall loading pyroclastic density current dynamic pressure and earthquake ground shaking intensities in refining these estimates for two case study areas kanlaon volcano in the philippines and fogo volcano in cape verde we have developed guidelines and methodologies for carrying out physical vulnerability assessments in the field these include identifying primary building characteristics such as construction material and method as well as subsidiary characteristics for example the size and prevalence of openings that may be important in assessing eruption impacts at risk buildings around kanlaon were found to be dominated by timber frame buildings that exhibit a high vulnerability to pyroclastic density currents but a low vulnerability to failure from seismic shaking around fogo the predominance of unreinforced masonry buildings with reinforced concrete slab roofs suggests a high vulnerability to volcanic earthquake but a low vulnerability to ash fall loading given the importance of agriculture for local livelihoods around kanlaon and fogo we discuss the potential impact of infrastructure vulnerability for local agricultural economies with implications for volcanic areas worldwide these methodologies and tools go some way towards offering a standardised approach to carrying out future vulnerability assessments for populated volcanic areas

volcanic hazard impacts to critical infrastructure a review abstract effective natural hazard risk assessment requires the characterisation of both hazards and vulnerabilities of exposed elements volcanic hazard assessment is at an advanced state and is a considerable focus of volcanic scientific inquiry whereas comprehensive vulnerability assessment is lacking cataloguing and analysing volcanic impacts provide insight on likely societal and physical vulnerabilities during future eruptions this paper reviews documented disruption and physical damage of critical infrastructure elements resulting from four volcanic hazards tephra fall pyroclastic density currents lava flows and lahars of eruptions in the last 100 years we define critical infrastructure as including energy sector infrastructure water supply and wastewater networks transportation routes communications and critical components common trends of impacts and vulnerabilities are summarised which can be used to assess and reduce volcanic risk for future eruptions in general tephra falls cause disruption to these infrastructure sectors reducing their functionality whilst flow hazards pyroclastic density currents lava flows and lahars are more destructive causing considerable permanent damage volcanic risk assessment should include quantification of vulnerabilities and we challenge the volcanology community to address this through the implementation of a standardised vulnerability assessment methodology and the development and use of fragility functions as has been successfully implemented in other natural hazard fields

erratum analysis of risk assessment factors of individuals in volcanic hazards review of the last decade journal of volcanology and geothermal research 2018 357 254 260 s0377027318300465 10 1016 j jvolgeores 2018 05 009

meddy trajectories in the canary basin measured during the semaphore experiment 1993 1995 as part of the structures des echanges mer atmosphere proprietes des heterogeneites oceaniques recherche experimentale semaphore experiment four mediterranean water eddies meddies were identified in the canary basin and tracked with freely drifting rafos floats one large and energetic meddy discovered 1700 km west of cape saint vincent portugal set a distance and speed record as it translated another 1700 km southwestward at 3 9 cm s during 1 5 years this meddy traveled 57 of the distance from cape saint vincent toward the spot mcdowell and rossby 1978 found a possible meddy north of the dominican republic two meddies were observed to interact with the azores current as they passed underneath or through it three meddies collided with tall seamounts which seemed to disrupt the normal swirl velocity perhaps fatally in two cases one meddy appeared to bifurcate when it collided with seamounts