present day kinematics of the mediterranean a comprehensive overview of gps results i combine recently published gps results to derive a geodetic horizontal velocity field consistent at the scale of the mediterranean and the surrounding alpine belts the velocity field is then used to discuss the boundary conditions around each major deforming area in the mediterranean to describe the main patterns of motion and deformation to critically review the existing kinematics models and to finally point out the main unresolved kinematics questions strain rate in europe north of the alpines belt is dominated by the signature of the glacial isostatic adjustment and tectonic strain remains below the current accuracy of gps results in the western mediterranean deformation is restricted to the betics the alboran and the morrocan rif with west to southwestward motion with respect to iberia which is part of stable europe shortening consistent with the relative nubia eurasia plate motion is found throughout the maghrebides but the distribution of deformation in northern africa remains largely unknown the central mediterranean is dominated by the counter clockwise rotation of the adriatic the junction between the southern adriatic domain and nubia has yet to be firmly established the deformation over a wide area east of the maghrebides in tunisia and the gulf of sirte in libya still remains to be quantified in the eastern mediterranean the velocity field is dominated by a general anti clockwise rotation and a general trend towards the hellenic trench with velocity magnitude increasing with decreasing distances from the trench this trend is observed not only in the aegean and anatolia but also in the southern balkans geodetic results emphasize that the convergence of the nubia and arabia plates towards eurasia directly controls the deformation across only very few segments along the plate boundary zone additional processes are therefore required to explain the observed velocity field and deformation pattern

tidal residual intertidal mudflat trim model and its applications to san francisco bay california abstract a numerical model using a semi implicit finite difference method for solving the two dimensional shallow water equations is presented the gradient of the water surface elevation in the momentum equations and the velocity divergence in the continuity equation are finite differenced implicitly the remaining terms are finite differenced explicitly the convective terms are treated using an eulerian lagrangian method the combination of the semi implicit finite difference solution for the gravity wave propagation and the eulerian lagrangian treatment of the convective terms renders the numerical model unconditionally stable when the baroclinic forcing is included a salt transport equation is coupled to the momentum equations and the numerical method is subject to a weak stability condition the method of solution and the properties of the numerical model are given this numerical model is particularly suitable for applications to coastal plain estuaries and tidal embayments in which tidal currents are dominant and tidally generated residual currents are important the model is applied to san francisco bay california where extensive historical tides and current meter data are available the model calibration is considered by comparing time series of the field data and of the model results alternatively and perhaps more meaningfully the model is calibrated by comparing the harmonic constants of tides and tidal currents derived from field data with those derived from the model the model is further verified by comparing the model results with an independent data set representing the wet season the strengths and the weaknesses of the model are assessed based on the results of model calibration and verification using the model results the properties of tides and tidal currents in san francisco bay are characterized and discussed furthermore using the numerical model estimates of san francisco bay s volume surface area mean water depth tidal prisms and tidal excursions at spring and neap tides are computed additional applications of the model reveal qualitatively the spatial distribution of residual variables

seismic investigation of the transition from continental to oceanic subduction along the western hellenic subduction zone 1 the western hellenic subduction zone whsz exhibits well documented along strike variations in lithosphere density i e oceanic versus continental subduction rates and overriding plate extension differences in slab density are believed to drive deformation rates along the whsz however this hypothesis has been difficult to test given the limited seismic constraints on the structure of the whsz particularly beneath northern greece here we present high resolution seismic images across northern and southern greece to constrain the slab composition and mantle wedge geometry along the whsz data from two temporary arrays deployed across greece in a northern line nl and southern line sl are processed using a 2d teleseismic migration algorithm based on the generalized radon transform images of p and s wave velocity perturbations reveal n60e dipping low velocity layers beneath both nl and sl the 8 km thick layer beneath sl is interpreted as subducted oceanic crust while the 20 km thick layer beneath nl is interpreted as subducted continental crust the thickness of subducted continental crust inferred within the upper mantle suggests that 10 km of continental crust has accreted to the overriding plate the relative position of the two subducted crusts implies 70 85 km of additional slab retreat in the south relative to the north overall our seismic images are consistent with the hypothesis that faster sinking of the denser oceanic portion of the slab relative to the continental portion can explain the different rates of slab retreat and deformation in the overriding plate along the whsz

multiproxy record for the last 4500 years from lake shkodra albania montenegro a multi proxy record is presented for approximately the last 4500 cal a bp from lake shkodra albania montenegro lithological analyses c n ratio and d 13 c of the organic and inorganic carbon component suggest that organic matter and bulk carbonate are predominantly authigenic the d 18 o record of bulk carbonate indicates the presence of two prominent wet periods one at ca 4300 cal a bp and one at ca 2500 2000 cal a bp the latter phase is also found in southern spain and central italy and represents a prominent event in the western and central mediterranean in the last 2000 years four relatively wet intervals occurred between ca 1800 and 1500 cal a bp 150 450 ad 1350 1250 600 700 ad 1100 800 850 1150 ad and at ca 90 cal a bp 1860 ad between ca 4100 and 2500 cal a bp d 18 o values are relatively high with three prominent peaks indicating drier conditions at ca 4100 4000 cal a bp ca 3500 and at ca 3300 cal a bp four additional drier events are identified at 1850 ca 100 ad 1400 ca 550 ad 1150 800 ad and ca 750 cal a bp 1200 ad the pollen record does not show changes in accordance with these episodes owing to the poor sensitivity of vegetation in this area which is dominated by an orographic rainfall effect and where changes in altitudinal vegetation belts do not affect the pollen rain in the lake catchment however since ca 900 cal a bp a significant decrease in the percentage arboreal pollen and in pollen concentrations suggest major deforestation produced by human activities copyright 2012 john wiley sons ltd

tectonic geomorphology and quaternary landscape development in the albania montenegro border region an inventory abstract young and recent tectonic activity can be discerned from instrumentally recorded seismic data as well as numerous geomorphological phenomena in the transition between the dinarides and hellenides fold and thrust belts we introduce a multiparametric approach using field remote sensing and seismic data from the region sw of shkodra lake between the towns of bar montenegro and lezha albania an area that offers unique opportunities of relating landscape development with tectonic deformation particularly we focus on windgap development on anticlines bound by pliocene quaternary active faults that allow statements on relative timing and rates of tectonic movement during the quaternary we propose an overall orogen perpendicular ne sw gradient from enhanced uplift and high tectonic activity in the hinterland to lower activity in the foreland an orogen parallel nw se gradient is added by the far field effects of shkodra peja transverse fault zone spfz these overall tendencies are valid despite a complex small scale mosaic of local differential uplift and subsidence recent gps studies and plate movement reconstructions are sparse providing rough estimates of 4 5 mm y horizontal and ca 1 mm y vertical movement geomorphological and paleoseismological studies are crucial to particularize recent and to estimate long term relative and absolute ground movement rates for this area

turbulence and entrainment in a buoyant surface plume in winter tidal outflow from the leschenault estuary forms a buoyant sheared stratified plume in koombana bay on each outgoing tide the turbulence in the plume and the local entrainment into the plume are examined based on measurements collected in an intensive field program coherency measurements between horizontally separated sensors are used to examine the anisotropy of the turbulence the effects of viscosity and buoyancy on the turbulence are studied using an activity diagram which is also an indicator of the mixing efficiency and total mixing the osborne cox model is tested and found to be valid in the plume

observations of stratified turbulent mixing in an estuary neap to spring variations during high river flow abstract observations of turbulent mixing stratification and currents were made with a free falling microstructure profiler and a 600 khz adcp in the hudson river off manhattan in may 1994 the ship was anchored in a relatively straight and uniform channel about 15 m deep over 4 days of intense observations from 19 to 24 may 1994 the progression from neap tides to spring tides caused a severe reduction in stratification from an initial top to bottom salinity difference of 18 to 3 6 while low gradient richardson numbers ri occurred only in the weakly stratified bottom layer on flood during neap tides low ri spanned the water column on the second half of ebb during spring tides turbulent dissipation rates varied roughly inversely to ri during neap conditions turbulent mixing was intense only in the bottom layer on flood where eddy diffusivities k reached more than 10 2 m 2 s 1 while mixing was weak in the centre of the halocline near 5 m during spring tides strong mixing occurred throughout the water column during the latter part of ebb with typical k 5 10 3 m 2 s 1 and typical vertical salt flux of 0 0015 kg m 2 s 1 if it existed in isolation this flux would eliminate the haline stratification on a time scale of 4 h ebb time bands of low ri and intense mixing showed increasing phase lag with increasing distance from the bottom the spring tide ebb time internal turbulent stress was relatively uniform with depth with a typical magnitude of 0 4 pa 4 dyne cm 2 turbulent overturning thorpe scales ranged from below 1 cm in the neap tide halocline to a few metres in the weakly stratified bottom layer on flood the strong spring tide ebb time mixing had thorpe scales of typically 0 5 m throughout the water column ozmidov scales tracked thorpe scales except in the weakly stratified layer above the bottom

longitudinal dispersion and lateral circulation in the intertidal zone 1 field observations indicate that a tidal salinity front that is regenerated each lower low water is a prominent feature of intertidal zone flow during wet winter months a strong longitudinal density gradient at the front influences flow dynamics through tidal straining and baroclinic forcing during each inundation period the salinity gradient disperses as it advects across the intertidal zone the average longitudinal dispersivity estimated from observations is about 10 m2 s 1 a three dimensional numerical model yields comparable estimates of tidally averaged dispersivity for an idealized bathymetry with a subtidal channel and intertidal shoals the instantaneous dispersivity through the tidal cycle depends on both vertical and lateral shear in along channel velocity dispersion due to vertical shear is greatest during stratified ebbs and inversely depends on tidal forcing dispersion due to lateral shear results from bathymetric variability between channel and shoal and increases with tidal amplitude similarly the along channel residual velocity is a combination of baroclinic and frictional processes frictional effects dominate the depth averaged residual such that net flow is upstream on the shoals and downstream in the channel however the frictional pattern is moderated by baroclinic forcing at the front although along channel dynamics dominate differential advection of the salinity front establishes lateral baroclinic circulation between channel and shoals lateral residual circulation is flood dominant with dense water moving out of channel near the bed and convergence from the shoals at the surface at times near the front the lateral salt flux can significantly affect the salinity budget in the channel

intratidal variations in stratification and mixing in the hudson estuary this study represents a detailed examination of intratidal variations in boundary layer structure in a relatively narrow straight section of the hudson river estuary during high river discharge the presence of active mixing is inferred from estimates of the richardson number the maximum height above bed to which mixing occurs is comparable during flood and ebb however the regions of mixing differ in density structure during the flood active mixing is confined to a well mixed near bed layer whereas during the ebb active mixing occurs throughout regions of significant stratification tidal straining maintains stratification during the ebb while it promotes the growth of a uniform bottom mixed layer during the flood in general maximum and minimum near bed stratification occur during late ebb and flood respectively reflecting the dominant role played by tidal straining in determining intratidal variation vertical stretching was also found to be an important term in the stratification balance during the ebb

gps constraints on current tectonics of albania abstract current tectonics of albania is documented by neotectonics evidences and by a large number of medium size earthquakes focal mechanisms suggest a current shortening across the external albanides whereas internal albanides are affected by extension with direction varying from e w to n s extension to investigate the kinematics of albanides we integrate continuous and episodic gps velocity measurements with focal mechanisms of the regional centroid moment tensor catalog this study has allowed distinguishing the followings 1 western albania affected by southwestward motions relative to apulia microplate the foreland of albanides illustrating the ongoing collision of external albanides 2 the inner albanides affected by a southward motion with a southward increase relative to both apulia and stable eurasia active thrusts and backthrusts of external albanides are segmented by strike slip faults the fault between the external albanides and the ionian zone appears to be particularly active the fault zone forming the boundary between dinarides and albanides is identified as the northern limit of an area including albania and western greece affected by a clockwise rotation relative to apulia and also the northern limit of the area inner albanides macedonia bulgaria affected by southward motion relative to apulia and stable eurasia the ene wsw transverse fault zone in central albania and western macedonia diber elbasani fault appears to be mainly affected by a moderate extension cgps data confirm that the external inner albanides transition is the western border of the domain inner albania northern greece macedonia bulgaria affected by southward displacements relative to stable eurasia and apulia whereas the fault zone forming the boundary between dinarides and albanides constitutes probably its northern limit

coastal dynamics under conditions of rapid sea level rise late pleistocene to early holocene evolution of barrier lagoon systems on the northern adriatic shelf italy this multidisciplinary case study of two preserved barrier systems combined the analysis of radiocarbon datings grain size distributions high resolution seismics and shelf bathymetry with reconstructions of palaeo environmental conditions tides waves sea level change and forward modelling of barrier lagoon systems to provide an integrated view of the coastal transgressive evolution of a large sector of the northern adriatic shelf between 15 and 8 ka bp palaeoenvironmental reconstructions point to increased tidal amplitude low energy wave climate and high rates of sea level rise up to 60 mm a during the formation of the oldest preserved barrier system not vert similar90 m water depth 14 3 cal ka bp a younger barrier system 42 m water depth 10 5 cal ka bp formed under conditions of lower tidal amplitude higher wave energy and a lower rate of sealevel rise 10 mm a forward modelling suggests that the probability of barrier island overstepping during transgression is inversely proportional to tidal amplitude if all other factors are assumed equal the oldest barrier lagoon system developed under conditions of large tidal amplitude which permitted rapid transgression however this system apparently failed to keep up with the anomalously high rate of sea level rise resulting from melt water pulse 1a the youngest barrier system appears to have drowned in place due to antecedent topography as the barrier system transgressed over an ancient pleistocene alluvial plain the rapid increase in backbarrier accommodation caused an abrupt disequilibrium between shoreface and backbarrier sedimentation which led to barrier overstepping although barsim modelling indicates that tidal deposition can reduce the probability of barrier overstepping there are other driving mechanisms in our case extremely rapid sea level rise and antecedent topography which are more determinative in explaining the transgressive coastal evolution of barrier lagoon systems in the northern adriatic sea grain size analysis of shoreface deposits sampled above the transgressive ravinement surface across the northern adriatic shelf indicate a distinct relation between the sediment grain size and the rate of sea level rise during deposition which implies that progressive sorting must have been highly effective

geodetic source modeling of the 2019 mw 6 3 durres albania earthquake partial rupture of a blind reverse fault author s govorcin m wdowinski s matos b funning gj abstract 2020 american geophysical union all rights reserved we address geometric and kinematic properties of the mw 6 3 26 november 2019 durres earthquake the strongest earthquake in albania in the past 40 years using coseismic surface displacements from sentinel 1 differential interferometric synthetic aperture radar dinsar and nearby global navigational satellite system gnss stations we invert for the geometry and slip of the causative fault we find that both a steep sw dipping fault dip 71 and a shallow ne dipping fault dip 15 can fit the data equally well however the slip on the sw dipping fault occurs at depths 11 23 km similar to the depths of the mainshock and aftershock seismicity and thus we prefer that model the location of our preferred fault plane correlates with the mapped sw dipping backthrust the vore fault the fault rupture did not reach the surface which implies that an updip stress propagation onto the unruptured shallow portion of the vore fault and its secondary structures pose an increased seismic hazard for cities in albania including the capital tirana

catalogue of ml 3 0 earthquakes in albania from 1976 to 1995 and distribution of seismic energy released abstract the construction of a catalogue of earthquakes in albania with ml 3 0 is described for the period 1976 1995 phase readings from 13 stations in the albanian seismological network and some nearby stations are employed some preliminary findings on recent seismicity in the country are presented a b value that is very near to long term value of this parameter is found only in a very few cases do hypocentral depths exceed 40 km there are about 400 felt earthquakes in the catalogue and of these 25 have caused damage on the basis of the whole catalogue and by calculating the seismic energy released for 220 cells covering the whole of albania an overview of the distribution of seismic energy and cumulative magnitudes is provided seven zones with high energy release for the period 1976 1995 are revealed the cumulative magnitude in these zones is more than 5 0 this analysis provides insight for a better understanding of the seismicity of albania and may assist in hazard assessments

paleomagnetism of external southern and central dinarides and northern albanides implications for the cenozoic activity of the scutari pec transverse zone paleomagnetic investigations have been conducted on 43 cretaceous to miocene sites 500 oriented cores from the southern and central external dinarides and from the northern external albanides the 24 reliable sites out of 33 from the dinarides do not document any significant rotation with respect to africa since at least early eocene this result contrasts with the very coherent post eocene 45 clockwise rotation previously observed in the external albano hellenides from peloponesus to the tirana basin these new results suggest that the scutari pec line located between the two orogens and considered as a mesozoic transform fault on the basis of geological observations is the place where the torsion between the dinarides and the albanides recently occurred on a local scale four sites out of 10 from two ridges located in northern albania south of the scutari pec line but with a dinaric trend show that these two structures have undergone a 30 post eocene clockwise rotation this intermediate value of rotation between the north and the south suggests that the scutari pec line is in fact a rather wide transversal zone in which the two ridges are located it acted as a decoupling zone between the dinarides and the albano hellenides during the cenozoic and probably until the pleistocene time the strong seismic activity recorded in this region and the anomalously high positive heat flow documented by other authors are also evidence for the recent activity of the scutari pec transverse zone

post glacial slip history of the sparta fault greece determined by 36cl cosmogenic dating evidence for non periodic earthquakes 1 using 36cl cosmic ray exposure dating we obtained continuous exposure histories for 7 12 m high limestone surfaces at two sites 10 km apart on the sparta normal fault scarp as each major earthquake adds new surface to the cumulative scarp exposing new material to cosmic ray bombardment these exposure histories allow the slip history to be constrained the results show that an earthquake occurred on this fault 2800 300 yr ago we infer that this is the seismic event that destroyed ancient sparta in 464 b c four earlier earthquakes ruptured the sparta fault in the last 13 ka with similar slip amplitudes of about 2 m and with time intervals ranging from 500 yr to 4500 yr the observations also confirm that the sparta scarp is post glacial supporting the hypothesis that similar scarps elsewhere in the mediterranean region have a comparable age the absence of any event since 464 b c could suggest a future event is imminent however the irregularity of earthquake time intervals could also be due to changes of loading with important consequences for the mechanics of continental deformation

the kefalonia transform fault a step fault in the making abstract vertical edges along subducted slabs have been recognized in the majority of subduction zones surprisingly slab edges evolved into subduction transform edge propagator step faults in only a few regions the conditions under which steps form are special it is relevant to constrain the conditions that facilitate step fault initiation because they leave a clear geological footprint in the overriding plate whereas vertical tears generally do not we therefore study a candidate region for step fault initiation in the western hellenic subduction zone we investigate the structure and seismicity of the shallow western hellenic subduction zone using a recent full waveform inversion model which both captures details of crustal and upper mantle structure yielding constraints in the depth interval from 10 to 200 km where lithosphere mantle interactions have tectonic expressions the western end of the hellenic subduction zone is fragmented near the kefalonia transform fault we identify a separate epirus lithospheric fragment that is roughly vertical below the southern albanides we also identify a new and major contrast within the lithospheric mantle of the ionian ocean basin which aligns with a gradient in free air anomalies in the overriding plate the kefalonia transform fault zone accommodates right lateral strike slip deformation we interpret this fault zone as a proto step fault that formed simultaneously with pliocene fragmentation of the epirus fragment comparing the recent evolution of the nw hellenic slab edge with currently active steps indicates that along trench variations in convergence velocity are a prerequisite for step fault initiation such velocity variations may result from subduction of continental crust along part of the trench resistance to sea ward tear propagation by a mechanically strong subducting plate may prevent variations in convergence velocity to occur and thus step fault initiation the amount of time over which a velocity contrast persists will also be relevant for step fault initiation mechanical coupling between upper and lower plate and the deformability of the upper plate appear to also play a role in the initiation of the step fault once a slab is fragmented

the montenegro yugoslavia earthquake of april 15 1979 source orientation and strength long period teleseismic p s and rayleigh waves and geologic considerations indicate that the montenegro earthquake involved thrust faulting on a plane striking nearly parallel to the adriatic coast and dipping ca 15 toward the yugoslav mainland there is some support from modeling of body waves recorded on long period wwssn instruments for a focal depth of 22 km but the possibility of a multiple source and the difficulty of matching some of the detailed characteristics of the p and s wave forms reduce our confidence in the determination of the depth fortunately the source orientation and moment of the event are not sensitive functions of the depth the long period 256 s moment was 4 6 10 19 nm 4 6 10 26 dyne cm the moment obtained by fitting the first cycle of p and s waves recorded on wwssn long period instruments is about four times smaller this increase of moment with period is consistent with spectral estimates of the moment from sh waves recorded at sro and asro stations

the dynamics of a partially mixed estuary measurements of velocity density and pressure gradient in the lower hudson river estuary were used to quantify the dominant terms in the momentum equation and to characterize their variations at tidal and spring neap timescales the vertical momentum flux assumed to be due mainly to turbulent shear stress was estimated indirectly based on the residual from the acceleration and pressure gradient terms the indirect estimates of stress compared favorably to bottom stress estimates using a quadratic drag law supporting the hypothesis that the tidal momentum equation involves a local balance between tidal acceleration pressure gradient and stress divergence estimates of eddy viscosity indicated that there was significant tidal asymmetry with flood tide values exceeding ebb values by a factor of 2 as a consequence of the asymmetry the vertical structure of the tidally averaged stress bore no resemblance to the tidally averaged shear in spite of the asymmetry of vertical mixing the tidally averaged estuarine circulation was found to depend simply on the intensity of bottom turbulence which could be parameterized by a rayleigh drag formulation based on the tidal velocity magnitude and the tidally averaged near bottom flow this seemingly paradoxical result indicates that the estuarine circulation can be modeled without detailed knowledge of the effective eddy viscosity only requiring an estimate of the bottom drag coefficient the tidal forcing conditions and the baroclinic pressure gradient a notable characteristic of this solution is an inverse dependence of the estuarine circulation on the amplitude of the tides

geodetic measurements of crustal deformation in the western mediterranean and europe geodetic measurements of crustal deformation over large areas deforming at slow rates 5 mm yr over more than 1000 km such as the western mediterranean and western europe are still a challenge because 1 these rates are close to the current resolution of the geodetic techniques 2 inaccuracies in the reference frame implementation may be on the same order as the tectonic velocities we present a new velocity field for western europe and the western mediterranean derived from a rigorous combination of 1 a selection of sites from the itrf2000 solution 2 a subset of sites from the european permanent gps network solution 3 a solution of the french national geodetic permanent gps network rgp and 4 a solution of a permanent gps network in the western alps regal the resulting velocity field describes horizontal crustal motion at 64 sites in western europe with an accuracy on the order of 1 mm yr or better its analysis shows that central europe behaves rigidly at a 0 4 mm yr level and can therefore be used to define a stable europe reference frame in that reference frame we find that most of europe including areas west of the rhine graben the iberian peninsula the ligurian basin and the corsica sardinian block behaves rigidly at a 0 5 mm yr level in a second step we map recently published geodetic results in the reference frame previously defined geodetic data confirm a counterclockwise rotation of the adriatic microplate with respect to stable europe that appears to control the strain pattern along its boundaries active deformation in the alps apennines and dinarides is probably driven by the independent motion of the adriatic plate rather than by the africa eurasia convergence the analysis of a global gps solution and recently published new estimates for the african plate kinematics indicate that the africa eurasia plate motion may be significantly different from the nuvel1a values in particular geodetic solutions show that the convergence rate between africa and stable europe may be 30 60 slower than the nuvelia prediction and rotated 10 30 counterclockwise in the mediterranean

vertical gps ground motion rates in the euro mediterranean region new evidence of velocity gradients at different spatial scales along the nubia eurasia plate boundary we use 2 5 to 14 years long position time series from 800 continuous global positioning system gps stations to study vertical deformation rates in the euro mediterranean region we estimate and remove common mode errors in position time series using a principal component analysis obtaining a significant gain in the signal to noise ratio of the displacements data following the results of a maximum likelihood estimation analysis which gives a mean spectral index 0 7 we adopt a power law white noise stochastic model in estimating the final vertical rates and find 95 of the velocities within 2 mm yr with uncertainties from filtered time series 40 smaller than from the unfiltered ones we highlight the presence of statistically significant velocity gradients where the stations density is higher we find undulations of the vertical velocity field at different spatial scales both in tectonically active regions like eastern alps apennines and eastern mediterranean and in regions characterized by a low or negligible tectonic activity like central iberia and western alps a correlation between smooth vertical velocities and topographic features is apparent in many sectors of the study area glacial isostatic adjustment and weathering processes do not completely explain the measured rates and a combination of active tectonics and deep seated geodynamic processes must be invoked excluding areas where localized processes are likely or where subduction processes may be active mantle dynamics is the most likely process but regional mantle modeling is required for a better understanding

geomorphic tectonic control of sediment discharge to the ocean the importance of small mountainous rivers analysis of data from 280 rivers discharging to the ocean indicates that sediment loads yields are a log linear function of basin area and maximum elevation of the river basin other factors controlling sediment discharge e g climate runoff appear to have secondary importance a notable exception is the influence of human activity climate and geology on the rivers draining southern asia and oceania sediment fluxes from small mountainous rivers many of which discharge directly onto active margins e g western south and north america and most high standing oceanic islands have been greatly underestimated in previous global sediment budgets perhaps by as much as a factor of three in contrast sediment fluxes to the ocean from large rivers nearly all of which discharge onto passive margins or marginal seas have been overestimated as some of the sediment load is subaerially sequestered in subsiding deltas before the proliferation of dam construction in the latter half of this century rivers

reconstructing the alps carpathians dinarides as a key to understanding switches in subduction polarity slab gaps and surface motion palinspastic map reconstructions and plate motion studies reveal that switches in subduction polarity and the opening of slab gaps beneath the alps and dinarides were triggered by slab tearing and involved widespread intracrustal and crust mantle decoupling during adria europe collision in particular the switch from south directed european subduction to north directed wrong way adriatic subduction beneath the eastern alps was preconditioned by two slab tearing events that were continuous in cenozoic time 1 late eocene to early oligocene rupturing of the oppositely dipping european and adriatic slabs these ruptures nucleated along a trench trench transfer fault connecting the alps and dinarides 2 oligocene to miocene steepening and tearing of the remaining european slab under the eastern alps and western carpathians while subduction of european lithosphere continued beneath the western and central alps following the first event post late eocene nw motion of the adriatic plate with respect to europe opened a gap along the alps dinarides transfer fault which was filled with upwelling asthenosphere the resulting thermal erosion of the lithosphere led to the present slab gap beneath the northern dinarides this upwelling also weakened the upper plate of the easternmost part of the alpine orogen and induced widespread crust mantle decoupling thus facilitating pannonian extension and roll back subduction of the carpathian oceanic embayment the second slab tearing event triggered uplift and peneplainization in the eastern alps while opening a second slab gap still present between the eastern and central alps that was partly filled by northward counterclockwise subduction of previously unsubducted adriatic continental lithosphere in miocene time adriatic subduction thus jumped westward from the dinarides into the heart of the alpine orogen where northward indentation and wedging of adriatic crust led to rapid exhumation and orogen parallel escape of decoupled eastern alpine crust toward the pannonian basin the plate reconstructions presented here suggest that miocene subduction and indentation of adriatic lithosphere in the eastern alps were driven primarily by the northward push of the african plate and possibly enhanced by neutral buoyancy of the slab itself which included dense lower crust of the adriatic continental margin

ongoing shortening in the dinarides fold and thrust belt a new structural model of the 1979 mw 7 1 montenegro earthquake epicentral region abstract this study focuses on structure and kinematics of the 1979 mw 7 1 montenegro earthquake although this event represents the strongest instrumentally recorded event in the entire dinarides hellenides fold and thrust belt no tectonic model relating this event to any particular fault existed so far we combined onshore geological information with well logs seismic lines bathymetric data seismotectonic and seismological data as well as cross section balancing techniques into a new structural model for the area our results suggest that main shock and strongest aftershock mw 6 2 occurred on the ne dipping basal thrust of a largely palaeogene age nappe system involving cretaceous neritic carbonates ongoing propagation of this thrust system is documented by the existence of elongated ridges located 15 km offshore reflection seismic and bathymetry data reveal that the ridges form crests of actively growing fault related anticlines slip distribution models of the strongest events imply that the basal thrust below the ridges accommodated up to 2 7 m of coseismic displacement ongoing shortening along the basal thrust also induced surface uplift of structurally higher thrust imbricates evidenced by dry valleys incising onshore anticline crests combining all evidence we speculate that the observed structural and geomorphic features resulted from repeated seismogenic faulting events as in 1979

regularity patterns and zones of seismic potential for future large earthquakes in the mediterranean region large earthquakes m 6 75 in the mediterranean region from iran to the azores were investigated with the aim of establishing possible regularity patterns in their occurrence and identifying regions of seismic potential the earthquakes investigated occurred along the complex boundaries in the zone of convergence between the eurasian and african arabian plates for both historic and modern times the magnitudes of some larger earthquakes were reconsidered the relatively complete record over a long period of time together with space time magnitude diagrams suggest the following patterns 1 1 an alteration of active and quiet seismic periods along the whole region 2 2 a cyclic eastward migration in the hellenic arc 3 3 average recurrence times of 100 150 yr for stress accumulation greece italy and 4 4 the triggering of the largest events at the eastern end of the north anatolian fault by stress transfer resulting from indentation of the arabian plate this has also been used as a hypothesis to explain the main features of space time earthquake evolution before the large 1939 earthquake finally using the observed regularities and some additional criteria e g the time elapsed since the last occurrence dimensions of rupture zones the following zones have been specially investigated with respect to their seismic potential 1 1 the eastern part of the north anatolian fault zone 2 2 northern marmara region 3 3 northeast of crete 4 4 south peloponnesus 5 5 southeastern sicily and central italy 6 6 west of gibraltar

the italian cmt dataset from 1977 to the present abstract the ingv harvard european mediterranean regional centroid moment tensor rcmt catalog collects solutions routinely computed since 1997 for earthquakes with moderate magnitude 4 5 m 5 5 in the mediterranean region the database represents an extension to smaller magnitudes of the harvard global cmt catalog based on analysis of seismograms recorded at regional distance and modeling of intermediate period surface waves the catalog includes about 600 events 200 of which in the italian region this study extends the catalog back in time for the italian region as long as made possible by available digital data i e since 1977 with the same analysis and inversion method used for current seismicity as a result we present here 65 new moment tensors for years between 1977 and 1997 these solutions represent 45 of the total number of events analyzed the existing seismograms being often too scarce to allow a stable solution the new dataset includes events in many seismic zones where moderate seismicity had previously been scarcely documented e g the po plain the central to southern apennines and the adriatic sea the complete dataset including previously determined rcmts and cmts represents the seismic deformation in the italian area during the last 25 years

scenarios of earthquake generated tsunamis for the italian coast of the adriatic sea we calculated the expected impact on the italian coast of the adriatic sea of a large set of tsunamis resulting from potential earthquakes generated by major fault zones our approach merges updated knowledge on the regional tectonics and scenario like calculations of expected tsunami impact we selected six elongated potential source zones for each of them we determined a maximum credible earthquake and the associated typical fault described by its size geometry and kinematics we then let the typical fault float along strike of its parent source zone and simulated all tsunamis it could generate simulations are based on the solution of the nonlinear shallow water equations through a finite difference technique for each run we calculated the wavefields at specified simulation times and the maximum water height field above mean sea level then generated travel time maps and maximum water height profiles along the target coastline maxima were also classified in a three level code of expected tsunami threat we found that the southern portion of apulia facing albania and the gargano promontory are especially prone to the tsunami threat we also found that some bathymetric features are crucial in determining the focalization defocalization of tsunami energy we suggest that our results be taken into account in the design of early warning strategies

long term accelerating foreshock activity may indicate the occurrence time of a strong shock in the western hellenic arc abstract in the decades prior to the occurrence of the 1899 ms 6 6 and 1947 ms 7 0 main shocks in the western hellenic arc wha the rate of occurrence of foreshocks ms 5 2 within a radius of 100 km around the epicenters can generally be said to have accelerated after a long period of very low foreshock activity stage i the process culminates in a final rapid acceleration of foreshocks some months before the main shocks stage ii while the last two months are quiescent stage iii these three stages are in good correspondence with the three stages of crustal deformation and several precursors to the main shock as predicted by the dilatancy model the data fit very well power law equations similar to those found for short term foreshocks of ordinary earthquakes and those associated with the creation of artificial lakes the position of the rupture zones of past wha strong shocks implies that the eastern part of the segment is the most probable location for the next strong shock in the arc a process of accelerating seismic activity similar to that which preceded the 1899 and 1947 shocks has been under way since 1966 around this part of the segment a comparison between changes in the power law curves for the earlier earthquakes and the one now expected indicates that the latter is now 3 8 months overdue assuming that the long term accelerating foreshock activity is a seismotectonic peculiarity of the wha segment i suggest that the preparation of the next rupture in the wha has entered a highly mature stage and that there will very probably be an earthquake in this area within the next few months

the cycle of turbulent dissipation in the presence of tidal straining in regions of large horizontal density gradient tidal straining acts to produce a periodic component of stratification that interacts with turbulent mixing to control water column structure and flow a 25 h series of measurements of the rate of dissipation of turbulent kinetic energy e in the liverpool bay region of freshwater influence rofi have revealed the form of this interaction and indicate substantial differences from regions where horizontal gradients are weak in the rofi system there is a pronounced difference between flood and ebb regimes during the ebb the water column stratifies and strong dissipation is confined to the lower half of the water column by contrast during the flood stratification is eroded with complete vertical mixing occurring at high water and high values of dissipation 3 mw m23 extending throughout the water column the cycle of dissipation is therefore predominantly semidiurnal in the upper layers whereas near the bottom boundary the principal variation is at the m4 frequency as observed in regions of horizontal uniformity toward the end of the flood phase of the cycle tidal straining produces instabilities in the water column that release additional energy for convective mixing confirmation of increased vertical motions throughout the water column during the late flood and at high water is provided by measurements of vertical velocity and the error velocity from a bottom mounted acoustic doppler current profiler

a 20th century acceleration in global sea level rise 1 multi century sea level records and climate models indicate an acceleration of sea level rise but no 20th century acceleration has previously been detected a reconstruction of global sea level using tide gauge data from 1950 to 2000 indicates a larger rate of rise after 1993 and other periods of rapid sea level rise but no significant acceleration over this period here we extend the reconstruction of global mean sea level back to 1870 and find a sea level rise from january 1870 to december 2004 of 195 mm a 20th century rate of sea level rise of 1 7 0 3 mm yr 1 and a significant acceleration of sea level rise of 0 013 0 006 mm yr 2 this acceleration is an important confirmation of climate change simulations which show an acceleration not previously observed if this acceleration remained constant then the 1990 to 2100 rise would range from 280 to 340 mm consistent with projections in the ipcc tar

tide gauge and gps measurements of crustal motion and sea level rise along the eastern margin of adria 1 we use observations from tide gauges and colocated continuous gps cgps stations to investigate crustal deformation and sea level changes along the eastern margin of the adriatic sea we develop a new method to separate common mode relative sea level from spatially variable signals precise vertical crustal motions determined by cgps allow us to further separate relative sea level into absolute sea level changes and crustal motions with respect to a local central mediterranean fixed gps defined reference frame from the tide gauge data we find fairly uniform relative sea level rise along the coast with mean rate of 0 84 0 04 mm yr and weighted rms variation about this mean of 0 2 mm yr this rate is a factor of 2 4 lower than estimates for global average sea level rise in contrast vertical motion of coastal rocks determined by cgps vary appreciably from an average of 1 7 0 4 mm yr in southern adria to 0 0 0 4 mm yr in northern adria this difference in crustal motion between the northern and southern regions is independent of our ability to separate sea level from crustal motion and may be explained by crustal strain associated with an active thrust fault accommodating southern adria microplate convergence with eurasia enigmatically the combination of tide gauge and cgps measurements shows that absolute sea level relative to the gps determined reference frame varies by as much as 1 8 mm yr along the croatian coast in such a way that the relative sea level remains roughly constant there are several potential explanations for this result deriving from ocean atmosphere and solid earth dynamics

crustal motion and deformation in greece from a decade of gps measurements 1993 2003 abstract the hellenic plate boundary region located in the collision zone between the nubian arabian and eurasian lithospheric plates is one of the seismo tectonically most active areas of europe during the last 15 years gps measurements have been used to determine the crustal motion in the area of greece with the aim to better understand the geodynamical processes of this region an extended reoccupation network covering whole greece has been measured periodically in numerous gps campaigns since the late eighties and a continuous gps network has been operated in the region of the ionian sea since 1995 in this paper we present a new detailed high quality solution of continuous and campaign type measurements acquired between 1993 and 2003 during the gps processing a special effort was made to obtain consistent results with highest possible accuracies and reliabilities data of 54 mainly european igs and euref sites were included in the gps processing in order to obtain results which are internally consistent with the european kinematic field and order to allow for a regional interpretation after an overview of the results of the igs euref sites the results from more than 80 stations in greece are presented in terms of velocities time series trajectories and strain rates previous geodetic geological and seismological findings are generally confirmed and substantially refined new important results include the observation of deformation zones to the north and to the south of the north aegean trough and in the west hellenic arc region arc parallel extension of about 19 mm yr along the hellenic arc and compression between the ionian islands and the greek mainland due to continuous long term observations of 4 8 years it was possible to extract height changes from the gps time series in greece we observe a differential subsidence of the order of 2 mm yr between the northern and central ionian islands across the kefalonia fault zone the differential subsidence of the central ionian islands with respect to the northwestern greek mainland amounts to 4 mm yr

finite fault slip models for the 15 april 1979 mw 7 1 montenegro earthquake and its strongest aftershock of 24 may 1979 mw 6 2 we revisit the april 1979 montenegro earthquake sequence to invert for finite fault slip models for the mainshock of 15 april 1979 mw 7 1 and of the strongest aftershock of 24 may 1979 mw 6 2 using p sh and sv waveforms retrieved from iris data center we also used body waveform modelling inversion to confirm the focal mechanism of the mainshock as a pure thrust mechanism and rule out the existence of considerable strike slip component in the motion the mainshock occurred along a shallow depth 7 km low angle 14 thrust fault parallel to the coastline and dipping to the ne our preferred slip distribution model for the mainshock indicates that rupture initiated from se and propagated towards nw with a speed of 2 0 km s moment was released in a main slip patch confined in an area of l 50 km w 23 km the maximum slip 2 7 m occurred 30 km to the nw of the hypocenter location of rupture initiation the average slip is 49 cm and the total moment release over the fault is 4 38e19 nm the slip model adequately fits the distribution of the mw 4 3 aftershocks as most of them are located in the regions of the fault plane that did not slip during the mainshock the 24 may 1979 mw 6 2 strongest aftershock occurred 40 km nw of the mainshock our preferred slip model for this event showed a characteristic two lobe pattern where each lobe is 7 5 7 5 km2 rupture initiated in the nw lobe where the slip obtained its maximum value of 45 cm very close to the hypocenter and propagated towards the south eastern lobe where it reached another maximum value for this lobe of 30 cm approximately 10 km away from the hypocenter to indirectly validate our slip models we produced synthetic pgv maps shake maps and we compared our predictions with observations of ground shaking from strong motion records all comparisons were made for rock soil conditions and in general our slip models adequately fit the observations especially at the closest stations where the shaking was considerably stronger through the search of the parameter space for our inversions we obtained an optimum location for the mainshock at 42 04 n and 19 21 e and we also observed that better fit to the observations was obtained when the fault was modeled as a blind thrust fault

late pleistocene holocene sea level rise and the pattern of coastal karst inundation records from submerged speleothems along the eastern adriatic coast croatia in order to reconstruct the late pleistocene holocene sea level rise along the eastern adriatic coast eight speleothems were collected from three submerged caves along the croatian coast from depths of 38 5 to 17 m the marine biogenic overgrowth layer and the youngest and the oldest parts of the speleothems were dated by the 14c method their stable isotope 13c 12c and 18o 16o contents were also measured from the measured 14c activity of the marine overgrowth and using the model of alessio et al 1992 risultati preliminari relativi alla datazione di speleotemi sommersi nelle fasce costiere del tirreno centrale giornale di geologia ser 3 54 2 165 193 the start of overgrowth i e the time of flooding by seawater was determined to be 10 185 cal bp at 36 m 9160 cal bp at 34 m and 7920 cal bp at 23 m our results partially match the sea level curves reconstructed for adjacent areas tyrrhenian coast and french mediterranean coast however the start of the marine overgrowth on speleothems in pit caves indicates strong dependence on the steepness of the terrain on steep extensively karstified coasts marine overgrowths on speleothems coincided with the submersion of the speleothems due to the relatively short distance between the pit and the open sea and fast penetration of seawater into the pit in contrast marine overgrowths on speleothems in pits in the flat terrains occurred later because speleothem growth ceased due to flooding with fresh groundwater later the fresh water was replaced by seawater due to the greater distance of the inland pits to the former coast

turbulence characteristics of a small subtropical estuary during and after some moderate rainfall in natural estuaries scalar diffusion and dispersion are driven by turbulence in the present study detailed turbulence measurements were conducted in a small subtropical estuary with semi diurnal tides under neap tide conditions three acoustic doppler velocimeters were installed mid estuary at fixed locations close together the units were sampled simultaneously and continuously at relatively high frequency for 50 hours the results illustrated the influence of tidal forcing in the small estuary although low frequency longitudinal velocity oscillations were observed and believed to be induced by external resonance the boundary shear stress data implied that the turbulent shear in the lower flow region was one order of magnitude larger than the boundary shear itself the observation differed from turbulence data in a laboratory channel but a key feature of natural estuary flow was the significant three dimensional effects associated with strong secondary currents including transverse shear events the velocity covariances and triple correlations as well as the backscatter intensity and covariances were calculated for the entire field study the covariances of the longitudinal velocity component showed some tidal trend while the covariances of the transverse horizontal velocity component exhibited trends that reflected changes in secondary current patterns between ebb and flood tides the triple correlation data tended to show some differences between ebb and flood tides the acoustic backscatter intensity data were characterised by large fluctuations during the entire study with dimensionless fluctuation intensity ib ib between 0 46 and 0 54 an unusual feature of the field study was some moderate rainfall prior to and during the first part of the sampling period visual observations showed some surface scars and marked channels while some mini transient fronts were observed

study of the montenegro earthquake sequence march july 1979 abstract data from more than 80 european seismic stations concerning foreshocks the main shock and aftershocks of the earthquake which occurred near the coast of montenegro on 15 april 1979 have been collected and analyzed the data have allowed the focal mechanism of the two strongest shocks to be estimated the hypocentral coordinates of more than 180 aftershocks and some foreshocks have been also computed giving the time space distribution of the sequence the shocks are mostly contained in an area about 100 km long and 30 km wide almost corresponding to the adriatic coast line of the yugoslavia albania border region the hypocentral depths although determined approximately appear to be in the order of 15 to 20 km the results have been compared with previous knowledge of the tectonics of the zone

late orogenic strike slip faulting and escape tectonics in frontal dinarides hellenides croatia yugoslavia albania and greece the frontal zone of the dinarides and its foreland are characterized by the presence of major late orogenic northwest southeast faults trending parallel to and locally dissecting the leading edge of the thin skinned thrust belt on the basis of their geometry and regional distribution these structures are interpreted as right lateral strike slip faults and are related to the formation of en echelon compres sional structures in the split dubrovnik area of the central adriatic region and to the opening of the post messinian pull apart albanian foredeep south adriatic basin in the pliocene holocene these strike slip faults represent the last stage of the mountain building process in the pliocene and holocene when the forelandward prop agation of the dinaric thrust belt was inhibited by stacking of thrust sheets and by overall thickening of the colliding continental crust in that respect the dinaric side of the apulia adria differs from the apenninic side where the thin skinned thrusting progressed normally toward the foreland until the pliocene on a regional scale these northwest southeast trending strike slip faults in the frontal dinarides and their apparent continuation to the hellenides of western greece as well as the dextral vardar fault system indicate the existence of escape tectonics in the di naric hellenic region during the last stage of orogeny the strike slip faults provided a means of tectonic transport from the collision zone of apulia with europe toward the subduction zone of the hellenic trench in southern greece the southeastward moving dinaric hellenic blocks apparently interfered with the westward moving anatolian plate and deflected it southwestward the albanian foredeep in terms of tectonic setting resembles the pull apart vienna basin which formed within the attenuated southwest northeast trending transfer zone of the west carpathi ans during the last stages of the alpine orogeny the late orogenic strike slip faulting may have breached seals and thus negatively affected the hydrocarbon potential of the dinaric hellenic side of the peri adriatic region as contrasted with that of the more prolific apenninic side which was not significantly disrupted by the late orogenic strike slip faulting

observations of turbulence in a partially stratified estuary the authors present a field study of estuarine turbulence in which profiles of reynolds stresses were directly measured using an adcp throughout a 25 h tidal day the dataset that is discussed quantifies turbulent mixing for a water column in northern san francisco bay that experiences a sequence of states that includes a weak ebb and flood that are stratified followed by a strong and eventually unstratified ebb and flood these measurements show that energetic turbulence is confined to a bottom mixed layer by the overlying stratification examination of individual reynolds stress profiles along with profiles of richardson number and turbulent froude number shows that the water column can be divided into regions based on the relative importance of buoyancy effects using the measured turbulence production rate p the dissipation rate e is estimated the observed turbulence had values of e nn 2 20 all of the time and e nn 2 200 most of the time suggesting that the observed motions were buoyancy affected turbulence rather than internal waves however at times turbulent froude numbers in much of the upper water column were less than one indicating important stratification effects taken as a whole the data show that stratification affects the turbulent velocity variance q2 most severely that is observed reductions in u9w9 are largely associated with small values of q2 rather than with a dramatic reduction in the efficiency with which turbulent motions produce momentum fluxes finally the dataset is compared to predictions made using the popular mellor yamada level 2 5 closure these comparisons show that the model tends to underestimate the turbulent kinetic energy in regions of strong stratification where the turbulence is strongly inhomogeneous and to overestimate the turbulent kinetic energy in weakly stratified regions the length scale does not appear to compensate for these errors and as a result similar errors are seen in the eddy viscosity predictions it is hypothesized that the underestimation of q2 is due to an inaccurate parameterization of turbulence self transport from the near bed region to the overlying stratification

the alteration of lateral circulation under the influence of human activities in a multiple channel system changjiang estuary abstract extensive coastal engineering activities including channel dredging and constructions of large infrastructure have greatly altered hydrodynamics in the changjiang estuary while the changes in longitudinal circulation have been well documented limited studies have focused on the alteration in lateral circulation and its impact on estuarine circulation in the changjiang estuary lateral circulation in an estuary plays an important role in modulating estuarine circulation sediment transport and morphological change different from many of previous numerical studies we utilize an unstructured grid numerical model configured in a way to allow inundation over dikes and tidal flats numerical model experiments show significant changes in lateral circulation and stratification along the north passage in response to the altered geometry and bathymetry due to the channel deepening and the dike construction both the channel deepening and the dike construction led to an enhanced stratification further analysis suggests that the along channel the lateral and the vertical including up and downwelling and vertical mixing effects are all important in modulating the intra tidal stratification destratification process the channel deepening enhances both the lateral and the vertical effects around the high water slack the construction of dikes that completely blocks the lateral water exchange between the north passage and surrounding tidal flats changes the system from a multiple channel system into a single channel system with dike construction the estuarine circulation tends to have a horizontally sheared pattern with weaker friction and a stronger stratification

stratification and turbulence in subtidal channels through intertidal mudflats 1 field observations in san francisco bay of subtidal channels that drain through intertidal mudflats indicate that substantial periodic stratification develops in very shallow flows with distinct asymmetries between flood and ebb conditions the greatest variability in salinity and stratification occurs during the wet winter months very strong longitudinal salinity gradients develop across the intertidal zone between salty subtidal water and fresher water draining into the marsh upstream tidal straining of the longitudinal gradient creates the periodic stratification stratifying through ebbs and destratifying through floods the stratification can be very strong in very shallow flows with n2 0 1 s 2 in about 0 5 m water depth analysis of the data with dimensionless numbers shows that at times the stratification is strong enough to suppress turbulence and mixing the asymmetry in stratification between ebbs and floods results in asymmetries in eddy viscosity and eddy diffusivity with lower values during the stratified ebbs because of the intertidal elevation of the system the strong longitudinal salinity gradient is regenerated each time the mudflats and marsh drain the system approaches a tidally periodic steady state where the flow dynamics are dominated by the sharp front of salty water that advects into the intertidal zone on the rising tide and exits the system by each lower low water the field data are supported by a numerical model with simple mudflat channel bathymetry both the field and numerical work indicate that the shallow low energy flows in mudflat channels transition between strongly stratified suppressed turbulence and relatively unstratified active turbulence each tidal cycle

turbulence in an estuarine embayment observations from beatrix bay new zealand 1 this study characterizes turbulence in a stratified estuarine embayment using measurements of temperature gradient microstructure the water column was generally strongly stratified with only moderate tidal forcing dissipation levels and turbulence length scales in the surface mixing layer the pycnocline the fluid interior and the benthic boundary layer were measured and compared with expectations based on previous work in different systems parameters important for modeling including the measured dissipation ratio d and the gradient richardson number rig were calculated the observations highlight a number of points 1 the lack of strong tidal flows means that buoyancy effects in estuarine embayments are more important than in the estuary proper 2 the combination of reduced tidal mixing and interacting thermohaline stratification suggests the importance in certain situations of diffusive convection 3 despite the shallow depths 40 m a number of hydrodynamic regimes vertically adjacent to one another exist resulting in a highly variable distribution of turbulence properties

modeling and understanding turbulent mixing in a macrotidal salt wedge estuary 1 a high resolution three dimensional numerical simulation is performed with the parallel unstructured grid suntans model to study the spatiotemporal dynamics of turbulent mixing in a shallow macrotidal salt wedge estuary that experiences periodic mixing and strong stratification unresolved vertical mixing is parameterized with the k kl closure scheme with the canuto a stability functions based on a careful comparison of multiple two equation closure schemes and stability functions via the generic length scale approach the predictions of velocity salinity richardson number and reynolds stress are in good agreement with field observations and the top and bottom salinity predictions achieve skill scores of 0 86 and 0 91 respectively the model shows that the salt wedge starts to strengthen upstream at the beginning of weak ebb and gradually expands downstream during the weak tide mixing is most active along a density interface during the weak ebb while it is most active in a bottom mixed layer during weak flood consistent with the findings inferred from the observations stratification decays during the strong ebb in a mixing event along the horizontal extent of the salt wedge while it is also being advected offshore local mixing is shown to account for roughly half of the decay rate of the stratification in this process numerical experiments are performed to investigate the response of stratification and mixing to changes in the magnitude of the buoyancy high sensitivity is shown under intermediate levels of stratification that occur in the real system which becomes considerably weaker under more extreme conditions

the adriatic region an independent microplate within the africa eurasia collision zone 1 we use gps measurements and block modeling to investigate the present day deformation of the adriatic region whose kinematics within the nubia eurasia plate boundary zone is not well constrained and remains controversial block modeling allows us to compute rigid plate angular velocities while accounting for elastic strain accumulation along block bounding faults results suggest that the adriatic is a microplate adria and that the southern boundary with the nubia plate and the aegean domain may be located along the apulia escarpment and the kefallinia fault geodetic data alone cannot discriminate between a single block ap or a two blocks gdap description of adria but the gdap model predicts boundary slip rates that are in better agreement with observations from previous studies

focal mechanism solutions for albanian earthquakes for the years 1964 1988 abstract focal mechanism solutions for 175 albanian earthquakes of albania for the years 1964 1988 were obtained by using an interactive computer technique the results obtained are elaborated upon by applying fisherian statistical analysis to obtain parameters for the mean stress direction in five zones to explain the results a wedging model in the interaction zone between the adria microplate and albanian orogen is suggested

evolution of the adriatic carbonate platform palaeogeography main events and depositional dynamics abstract the adriatic carbonate platform adcp is one of the largest mesozoic carbonate platforms of the perimediterranean region its deposits comprise a major part of the entire carbonate succession of the croatian karst external or outer dinarides which is very thick in places more than 8000 m and ranges in age from the middle permian or even upper carboniferous to the eocene however only deposits ranging from the top of the lower jurassic toarcian to the top of the cretaceous can be attributed to the adcp defined as an isolated palaeogeographical entity although the entire carbonate succession of the karst dinarides was deposited within carbonate platform environments there were different types of carbonate platforms located in different palaeogeographical settings carboniferous to middle triassic mixed siliciclastic carbonate deposits were accumulated along the gondwanian margin on a spacious epeiric carbonate platform after tectonic activity culminating by regional middle triassic volcanism recorded throughout adria the african promontory a huge isolated carbonate southern tethyan megaplatform abbreviated as stm was formed with the area of the future adcp located in its inner part tectonic disintegration of the megaplatform during the middle to late early jurassic resulted in the establishment of several carbonate platforms including the adriatic apenninic and apulian separated by newly drowned deeper marine areas including the adriatic basin as a connection between the ionian and belluno basins lagonero basin and the area of the slovenian and bosnian troughs the adcp was characterised by predominantly shallow marine deposition although short or long periods of emergence were numerous as a consequence of the interaction of synsedimentary tectonics and eustatic changes also several events of temporary platform drowning were recorded especially in the late cretaceous when synsedimentary tectonics became stronger leading up to the final disintegration of the adcp the thickness of deposits formed during the 125 my of the adcp s existence is variable between 3500 and 5000 m the end of adcp deposition was marked by regional emergence between the cretaceous and the palaeogene deposition during the palaeogene was mainly controlled by intense synsedimentary tectonic deformation of the former platform area some carbonates mostly eocene in age were deposited on irregular ramp type carbonate platforms surrounding newly formed flysch basins and the final uplift of the dinarides reached its maximum in the oligocene miocene the adriatic carbonate platform represents a part although a relatively large and well preserved one of the broader shallow water carbonate platform that extended from ne italy to turkey although its continuity is somewhat debatable in the area near albanian greece boundary this large carbonate body which was deformed mostly in the cenozoic including a significant reduction of its width needs a specific name and the central mediterranean carbonate platform is proposed abbreviated to cmcp although the local names such as adcp for its nw part should be kept to enable easier communication and to facilitate description of local differences in platform evolution

historical evolution and middle to late holocene environmental changes in lake shkodra albania new evidences from micropaleontological analysis abstract the 7 5 m long sk13 sediment core drilled at lake shkodra albania at a bottom depth of 7 m in the central southern part of the lake was selected for multidisciplinary analysis the sediment core age spans from 4560 cal yr bp to present the origin and the evolution of the lake are still debated and were never investigated in detail in historical records until the 15th century lake shkodra was never mentioned as such but as a marshland or as a confluence between two rivers our research aims to reconstruct the past biodiversity and the middle late holocene palaeoenvironmental and palaeoclimatic changes using ostracods characeae and comparing the micropaleontological data with pollens and stable isotope curves thirteen ostracod and five charophyte species were identified amongst the ostracods candona montenigrina and limnocythere scutariense are endemic of the lake candona meridionalis paralimnocythere georgevitschi metacypris cordata candona ex gr bimucronata and cyclocypris sp have been collected for the first time in lake shkodra the last three taxa occurred only in the lower portion of the sediment core amongst the charophytes lychnothamnus barbatus and nitella hyalina are recorded for the first time in the lake and occurs with high frequency throughout the lower portion of the core a drastic change occurs between 1274 and 1197 cal yr bp when 8 ostracod species out of 13 and all charophytes disappear and the frequency of the remaining 5 species dramatically increases the micropaleontological data suggest a decrease of the lake biodiversity since around 1200 cal yr bp linked to the transition between an ancient marshland to a lacustrine environment this drastic event seems to be independent from any global or local climate change but linked to the complex hydrographic setting of the lake and of its only outlet the river bojana discharging in the adriatic sea

glacio eustatic control of continental shallow marine cyclicity from late quaternary deposits of the southeastern po plain northern italy abstract integrated sedimentological and micropaleontological foraminifera ostracods pollens investigations of a 173 m long continuous core in the subsurface of the se po plain reveal a cyclic facies distribution of continental to shallow marine deposits radiometric and pollen data enable an age attribution of the study units to the late middle pleistocene holocene glacioeustasy appears to have exerted a major control on facies development as documented by the close relationships between cyclic lithofacies patterns and the curves of eustatic fluctuation particularly relative sea level falls and lowstand phases were characterized by the development of alluvial sedimentation whereas major transgressive pulses and subsequent highstands are reflected by abrupt shifts to paralic and shallow marine deposits this facies architecture is paralleled by a distinctive pollen distribution reflecting the alternation of a glacial type of vegetation dominated by pinus and nonarboreal pollen types with interglacial mixed deciduous broad leaved forests

coupled crust mantle response to slab tearing bending and rollback along the dinaride hellenide orogen we integrate structural geophysical and geodetic studies showing that the dinarides hellenides orogen along the adria europe plate boundary in the western balkan peninsula has experienced clockwise oroclinal bending since eocene oligocene time rotation of the hellenic segment of this orogen has accelerated since the middle miocene and is associated with a north to south increase in shortening along the orogenic front within the paleogene nappe pile bending was accommodated by orogen parallel extension clockwise block rotation and thrusting in the hanging wall of the skhoder peja normal fault spnf the spnf and related faults cut the older skhoder peja transfer zone with its pre neogene dextral offset of the west vardar ophiolite nappe rotation of the spnf hanging wall involved miocene to recent out of sequence thrusting that was transferred to the hellenic orogenic front via lateral ramps on dextral transfer zones along strike of the dinarides hellenides and coincident with the southward increase in neogene shortening the depth of the adriatic slab increases from 160 km north of the spnf to 200 km just to the south thereof to several hundreds of kilometers to the south of the kefalonia transfer zone the geodynamic driver of tectonics since the early miocene has been enhanced rollback of the hellenic segment of the adriatic slab in the aftermath of eocene oligocene slab tearing and breakoff beneath the dinarides which focused slab pull in the south the sw retreating hellenic slab segment induced clockwise bending of the southern dinarides and northern hellenides including their adriatic foreland about a rotation pole in the vicinity of the mid adriatic ridge

eddy characteristics in the eastern south pacific 1 the main eddy characteristics length scales rotation period swirl and translation velocities are determined in the eastern south pacific region 10 35 s and 70 100 w based on surface drifter measurements satellite altimetry and hydrographic data from the woce p19 section the chile peru current eddies have a typical diameter of order of 30 km smaller than the typical rossby radii observed in the region they are principally formed near the south american coast and propagate seaward with a translation velocity varying from 3 cm s 1 in the southern part of the study domain to 6 cm s 1 north of 15 s long lived anticyclonic eddies propagate northwestward with a mean angle of around 333 t whereas cyclonic vortices propagate westward consistent with the vortices propagation theory on a plane the radial distribution of the swirl velocity shows that the chile peru current eddies have a maximum diameter of order 200 km with a swirl velocity of around 14 cm s 1 and a rotation period of 50 days hydrographic data reveal a vertical extent down to around 2000 m for energetic eddies no significant difference is observed between the tangential velocities of cyclonic and anticyclonic eddies geostrophic balance can be considered for large radii whereas ageostrophic dynamics may play an important role near the eddy centers