sequence stratigraphy tectonics and depositional history in eastern thrace basin nw turkey abstract the eastern thrace basin forms the eastern portion of the turkish thrace basin in nw turkey the pre tertiary crystalline basement shows platform and deep basin depositional morphology which results in facies pattern and thickness distribution localization during the early stages of basin development in middle to late eocene time normal fault controlled early and lateral reverse fault controlled later stage tectonic events characterize basin geometry and the present topography respectively the early stage normal faulting caused subsidence and sediment accumulation in the late eocene and early oligocene while later stage tectonic events caused intense deformation and structuration in the early to middle miocene as a result southeastern and northern regions were folded or uplifted and deeply eroded outcrop well log core and reflection seismic studies reveal that the sedimentary succession can be subdivided into five characteristic depositional sequences bounded at their base by unconformities these unconformities were dated using paleontological data the sequence boundaries underlying consecutively sequences 1 2 3 and 5 were dated at 39 5 36 30 and 25 5 ma from older to young in order of succession corresponding to the major erosional breaks between the middle and upper eocene the upper eocene and the lower oligocene the lower and upper oligocene and the upper oligocene and the lower miocene the sequence boundary underlying sequence 4 was determined to lie within the late oligocene succession and as an age designation could not be assigned it was termed intra sequence boundary isb the first two sequences correspond to relative sea level rises and a normal fault controlled tectonism coincides with them reefal carbonates coarse grained clastics and marine shales with abundant volcanic flows or layers represent the sedimentary facies of these two early sequences the third and fourth sequences correspond to either a decreased relative rise of sea level or a relative still stand of sea level and a sediment induced subsidence related to thermal relaxation provides accommodation prograding delta sediments of varying extent constitute the sedimentary packages of these two sequences the depositional sequence 5 which makes up the uppermost part of the sedimentary succession in the basin corresponds to a relative sea level fall and a tectonic style shaped by lateral and inversion faulting characterizes this period nonmarine alluvial fan fluvial channel and various lagoonal deposits constitute the sedimentary facies of this last sequence porous reefal limestones and shallow marine beach sandstones of sequence 1 and deltaic sandstones of sequences 3 and 4 provide good reservoir rocks for the hydrocarbons produced in the study area the marine shales and marls of the second and the third sequences provide good source rocks as they are rich in disseminated organic matter content although the non marine alluvial and fluvial channel deposits of sequence 5 are good reservoirs they lack effective seals the time interval in which sequence 5 was deposited represents a period of major structural and trap development in the basin

distribution and mass of tephra fall deposits from volcanic eruptions of sakurajima volcano based on posteruption surveys we estimate the total mass of ash fall deposits for individual eruptions of sakurajima volcano southwest japan based on distribution maps of the tephra fallout five ash sampling campaigns were performed between 2011 and 2015 during which time sakurajima continued to emit ash from frequent vulcanian explosions during each survey between 29 and 53 ash samplers were installed in a zone 2 2 43 km downwind of the source crater total masses of erupted tephra were estimated using several empirical methods based on the relationship between the area surrounded by a given isopleth and the thickness of ash fall within each isopleth we obtained 70 40 520 t 4 7 10 8 2 7 10 5 km3 dre as the minimum estimated mass of erupted materials for each eruption period the minimum erupted mass of tephra produced during the recorded events was calculated as being 890 5140 t 5 9 10 7 3 6 10 6 km3 dre this calculation was based on the total mass of tephra collected during any one eruptive period and the number of eruptions during that period these values may thus also include the contribution of continuous weak ash emissions before and after prominent eruptions we analyzed the meteorological effects on ash fall distribution patterns and concluded that the width of distribution area of an ash fall is strongly controlled by the near ground wind speed the direction of the isopleth axis for larger masses is affected by the local wind direction at ground level furthermore the wind direction influences the direction of the isopleth axes more at higher altitude while a second maximum of ash fall can appear the influence of rain might only affect the finer particles in distal areas

recent volcanic events and the distribution of hydrothermal venting at the lucky strike hydrothermal field mid atlantic ridge 1 we present new high resolution bathymetry and backscatter data acquired in 2006 with the rov victor 6000 over the lucky strike hydrothermal field mid atlantic ridge as long term monitoring of the lucky strike area momar project is being implemented these new high resolution data offer an unprecedented view of the distribution of hydrothermal edifices eruptive facies and small scale tectonic features in the lucky strike vent field we show that vents located in the nw and ne correspond with wide expanses of lumpy seafloor which we interpret as primarily made of broken chimneys and sulfide edifices they are found above scarps with relief 50 m or on associated mass wasting deposits by contrast the se and sw vents correspond with small expanses of lumpy seafloor and are located near smaller scarps which we interpret as more recent faults hydrothermal edifices in the sw venting area appear very recent postdating the emplacement and faulting of the most recent lava we propose that this difference in the age of hydrothermal edifices does not mean that hydrothermal venting itself is more recent in the southern part of the lucky strike field because preexisting sulfide deposits there may have been buried by recent volcanic deposits instead the older edifices in the northern part of the hydrothermal field may have been allowed more time to grow because they are set above the level of recent lava flows the formation of a lava lake is the most recent eruptive event detected at lucky strike lava drainback is evidenced by benches and lava pillars suggesting a close connection with an underlying magma reservoir which probably corresponds to the melt body imaged by singh et al 2006 we have found no evidence that this lake was active for months to decades as lava lakes at terrestrial volcanoes it may instead have formed as a lava pond with successive lava flows covering the eruptive vents as proposed for similar features at the epr the horizontal surface of the lake is deformed only near its southwestern shore along a nne trending set of faults and fissures which appear to control the distribution of hydrothermal chimneys

constraints on the kinematics of post orogenic extension imposed by stretching lineations in the aegean region abstract new kinematic data from shear zones of tertiary age in the metamorphosed basement of the aegean region in combination with published kinematic lithological and palaeomagnetic data have enabled us to determine a detailed kinematic evolution of the region during post orogenic extension in the aegean three distinct stages are recognised firstly extension of both the western and eastern aegean started in the late oligocene early miocene 36 25 ma ago initially in an 023 direction stage two started shortly after this with the division of the aegean crust into the west aegean block a coupled assemblage of small blocks bound on its northwestern and southeastern margins by the scutari pec line and mid cycladic lineament fracture zones respectively between 25 ma and 3 ma the west aegean block underwent 30 clockwise rotation whilst the eastern aegean underwent on average 19 anticlockwise rotation rotation of the west aegean block as a semi coherent block was aided by the relative coolness of the block compared to the warmer eastern aegean region as the crust thinned and rotated the nw se trending faults which characterise the west aegean block were cross cut by e w trending faults in the latest miocene pliocene the thermal front migrated westwards into the west aegean block and the mid cycladic lineament ceased activity the final kinematic stage marked the start of the subdivision of the west aegean block into two portions in the pliocene the southeastern portion nw cycladic area coupled with the sw cycladic area to form a central aegean block that started to translate southwest the northern and western portion rotated a further 10 15 clockwise whilst the southeastern rim rotated anticlockwise these data demonstrate that aegean post orogenic extension is not dominated by a single block rotation or radial spreading event but is characterised by the sequential formation and reformation of lithospheric scale blocks that have developed in response to large scale partitioning of rotational strain

velocity and deformation fields in the north aegean domain greece and implications for fault kinematics derived from gps data 1993 2009 abstract gps rates based on data of an extended continuous and campaign type gps network in the north aegean domain are presented the data processed for the time period 1993 2009 is used to analyze the complex kinematic and deformation fields in the north aegean sea and adjacent regions the presence of slowly deforming areas is investigated southern bulgaria eastern macedonia and thrace move uniformly southward relative to eurasia 1 5 3 5 mm yr western macedonia epirus thessaly and central greece rotate rather coherently clockwise the region comprising the islands of limnos agios efstratios and alonnisos moves like a counterclockwise rotating slowly deforming block the new gps rates allow a quantification of the spatial change of strike slip motion and locking depth along the north aegean trough dextral strike slip motion diminishes from east toward west amounting to 21 2 mm yr along the saros basin and 12 5 mm yr south of the chalkidiki peninsula less than 5 mm yr 50 nstrain yr shear strain rate is transferred from the sporades islands pelion toward northern evia the locking depth is shallow for the ganos fault and the western saros basin 5 6 8 9 km it is deeper between the sporades islands and pelion 17 7 km corresponding to a more diffuse shear zone an elementary finite element model is applied to derive slip rates of the three main ene wsw to ne sw trending dextral strike slip faults in the north aegean large scale n s to nne ssw extension in the north aegean domain is analyzed by employing finite element and gps based strain rate analyses pronounced extension 100 nstrain is associated with known tectonic structures e g mygdonian graben northern gulf of evia in offshore areas such as the sporades basin the correspondence between gps derived extension rates and active fault structures is not entirely evident however important constraints are provided for seismotectonic interpretations

exhumation of high pressure rocks driven by slab rollback rocks metamorphosed under high pressure hp and ultra high pressure uhp conditions in subduction zones come back to the surface relatively soon after their burial and at rates comparable to plate boundary velocities in the mediterranean realm their occurrence in several belts related to a single subduction event shows that the burial exhumation cycle is a recurrent transient process using the calabria apennine and aegean belts as examples we show that the exhumation of hp rocks is associated in time and space with the subduction of small continental lithosphere blocks that triggers slab rollback creating the necessary space for the exhumation of the buoyant continental crust that was deeply buried just before the buoyancy force of the subducted crust increases until this crust detaches from the downgoing slab it then exhumes at a rate that depends directly on the velocity of trench retreat to become part of the overriding plate heated from below by the asthenosphere that flows into the opening mantle wedge the exhumed crust weakens and undergoes core complex type extension responsible for a second stage of exhumation at a lower rate the full sequence of events that characterizes this model crust mantle delamination slab rollback and trench retreat hp rock exhumation asthenosphere heating and core complex formation arises entirely from the initial condition imposed by the subduction of a small continental block no specific condition is required regarding the rheology and erosion rate of hp rocks the burial exhumation cycle is transient and can recur every time a small continental block is subducted

large inversions of altimeter and tied tide gauge data for the mediterranean sea mean surface satellite altimeter measurements and tide gauge data tied ttg data to a global geodetic reference frame by space techniques of positioning will provide in a near future consistent and complementary information to map the mean sea surface mss with a subdecimetric absolute accuracy information is consistent because after standard data processing both kinds of sea level measurements are given relative to the same geocentric reference ellipsoid information is also complementary because first satellite altimetry draws a dense sampling pattern of the ocean while ttg measurements are local second the properties of the data errors are very dissimilar in the two techniques both kind of sea level measurements are already available in the mediterranean basin this study is the first attempt to compute an accurate mss model with mixed sets of such data a total inverse method previously developed to analyze satellite altimetry is greatly improved in order to recover a full spectrum of the mss down to wavelengths 100 km and to invert rigorously large data sets including consecutive satellite tracks the mss solution derived solely from altimetry in the mediterranean sea has a formal error of 12 cm under the repeat satellite tracks up to 30 cm near the coasts with a further truncation error of 10 cm then an analysis of the discrepancy between this solution and ttg data allows us to point out unsuspected inconsistencies in the two data sets which are clearly identified nevertheless the usefulness of the ttg data is demonstrated by an estimate of their impact on the error spectrum of the mss

how radial orbit errors are mapped in altimetric surfaces in the radar altimeter measurement of the satellite height above the instantaneous sea surface radial orbit errors are mapped on the earth with the spacecraft motion in many geophysical and oceanographical applications of satellite altimetry a precise knowledge of the mapped error features is necessary to estimate sea or ice sheet surface topographies and to assess their absolute accuracies so we derive a general formulation to infer from any a priori time spectrum of orbit errors the characteristic wavelengths of the mapped error biasing the recovery of a sea surface topography because of commensurability between the satellite motion and earth rotation radial orbit errors at the nodal or orbital periods and their harmonics are mapped into smooth long wavelength surfaces and fully aliased in the steady surface topography as this phenomenon presents a close relationship with the resonance of the orbit perturbations we suggest naming it the mapped orbit error resonance our formulation also provides an explicit account of both time and space sampling effects on the correlation of the mean sea surface oceanic tides and orbit errors for instance the typical wavelength of a resonant mapped error is scattered by the land gaps in all the near wavelengths of an oceanic surface the derived mapping function also seems to indicate that the statistics of the crossover differences are unable to estimate the absolute precision of altimetric surfaces because a nonnegligible portion of radial orbit errors falls into the steady component of the sea surface

nudging satellite altimeter data into quasi geostrophic ocean models this paper discusses the efficiency of several variants of the nudging technique derived from the technique of the same name developed by meteorologists for assimilating altimeter data into numerical ocean models based on quasi geostrophic formulation assimilation experiments are performed with data simulated in the nominal sampling conditions of the topex poseidon satellite mission under experimental conditions it is found that nudging on the altimetric sea level is as efficient as nudging on the vorticity second derivative in space of the dynamic topography the technique used thus far in studies of this type the use of altimetric residuals only instead of the total altimetric sea level signal is also explored the critical importance of having an adequate reference mean sea level is largely confirmed finally the possibility of nudging only the signal of sea level tendency i e the successive time differences of the sea level height is examined apart from the barotropic mode results are not very successful compared with those obtained by assimilating the residuals

delta progradation and sediment fluxes since the last glacial in the thermaikos gulf and the sporades basin nw aegean sea greece abstract late quaternary sedimentary cover in the thermaikos gulf consists of three seismic units i the uppermost unit a that represents delta progradation during the last 6000 yr when the sea surface almost reached the present level highstand systems tract hst ii unit b that includes relatively coarse grained sediments deposited in a shallow high energy estuarine environment during the post glacial transgression transgressive systems tract tst and iii the lowest unit c which may represent late glacial prodeltaic deposits and slope to basin turbidites lowstand systems tract lst seismic units a and b overlay a well defined unconformity which resulted from sub aerial erosion during the late glacial sea level fall subtracting the thickness of unit a from the present bathymetry the paleo relief of the late holocene times ca 6000 yr bp sea level up to 20 m was assessed similarly the paleo relief 24 000 yr bp sea level 100 to 120 m was estimated the main morphological feature is the incised valley of a major river that resulted from the confluence of the axios aliakmon loudias gallikos and possibly pinios rivers sediment fluxes in the nw aegean sea were estimated for three time spans of the late quaternary interval i 6000 yr bp present interval ii 18 000 6000 yr bp and interval iii 24 000 18 000 yr bp the terrestrial sediment load supplied by the axios aliakmon pinios and smaller rivers was estimated at 35 4 10 9 t for interval i 93 of this material was deposited on the continental shelf whereas the remaining 7 was transported to the adjacent basin the mean annual terrestrial flux was estimated at 5 5 10 6 t yr 1 during interval ii more than 79 10 9 t of terrestrial sediment were discharged into the area terrestrial flux 6 6 10 6 t yr 1 of which 86 was deposited on the shelf during interval iii the terrestrial load was 40 6 10 9 t terrestrial flux 6 8 10 6 t yr 1 and sediments were predominantly deposited on the slope and basin based on the sediment s carbonate content the biogenic loads and fluxes were also determined the biogenic flux during intervals ii and iii was found to be 2 5 times higher than during interval i

gravity model improvement for seasat analysis of the data from the seasat altimeter a 10 cm precision instrument requires accurate knowledge of the radial position of the spacecraft for oceanographic applications such as the study of tides and ocean circulation as well as for geodetic applications initial orbit determinations using the best available geodetic and force models gave radial errors approaching 5 m the dominant source of this radial error was the gravity field model improvements in the gravity modeling were made by successively incorporating the seasat laser and unified s band ground tracking data the geos 3 altimeter data and finally the seasat altimeter data with the most recent model a set of spherical harmonic coefficients complete to degree and order 36 seasat ephemerides have been computed for an orbital arc length of 12 days with an rms radial accuracy of about 70 cm

accuracy estimate of geoid and ocean topography recovered jointly from satellite altimetry joint determination of the geoid and permanent dynamic sea topography is demonstrated by simulation from direct use of satellite altimetry the separation is feasible because of the disparities between the error spectra of the geoid and its unique perturbative effects as seen on the orbit the solution for the components of the permanent topography from 14 cm seasat altimetry promises to yield accurate results down to half wavelengths of about 1000 km present discrimination of this surface from disjoint satellite altimeter results appears to be at a scale near 4000 km the radial effects of uncertainties in the m2 ocean tide on the seasat orbit and altimeter measurements will probably be only a minor contaminant of the solution

eocene stratigraphic evolution of the thrace basin turkey abstract this paper explains the primary basin evolution processes of the thrace basin which started opening during early middle eocene stratigraphic and tectonic models for different parts of the basin have been constructed and basin scale stratigraphic correlations were established by using outcrop well and seismic data initial deposits of eocene in the thrace basin show irregular depositional patterns associated with various lithofacies deposited under the control of various tectonostratigraphic settings first a compressional regime started after the collision of the sakarya continent with the rhodope pontide fragment in late cretaceous paleocene enabled initiation of transtensional stress which was responsible for the creation of necessary accommodation space for deposition of the initial thrace sediments in the northern and eastern part of the thrace basin the lower middle eocene hamitabat formation was deposited in this kind of transtensional setting and can be divided into various lithostratigraphic units an unconformity identified within hamitabat formation from seismic and well data divides it to two major units in early eocene the thrace basin was deepening eastwards and deposition was initiated between finger shaped paleo highs aligned in an e w direction thus synchronous erosional and depositional events in different parts of the basin formed various facies associated with a variety of depositional environments during the same time interval a regional unconformity at the base of lower eocene between karaagac and hamitabat formations can be correlated from south to north moreover the unconformity between lower middle eocene deposits and the middle eocene limestones of southern thrace is correlative with the unconformity between the hamitabat formation and overlying upper eocene limestones at northern regions this unconformity has a correlative conformity within the gazikoy or kesan formations in central thrace where continuous deposition took place during eocene without interruption

the continuity of active fault systems in greece summary evidence from geomorphology the distribution of large earthquakes and geodetic measurements suggests that the active faulting in mainland greece and the north aegean sea is concentrated into a small number of discrete linear zones that bound relatively rigid blocks on land the zones are most clearly identified where the faulting is associated with large escarpments particularly in hard footwall rocks the zones can become indistinct and diffuse near their ends sometimes because they enter high unstable topography where landsliding obscures the fault morphology but mostly because the extension rates decrease along strike as a consequence of the relative rotation of the blocks they bound the main graben systems of chalkidiki southern thessaly and the north gulf of evia all seem to connect with the strike slip faulting in the offshore aegean and to die out in the west a configuration related to clockwise rotations in east central greece by contrast the gulf of corinth which is the fastest opening graben system in greece opens more rapidly in the west than the east both these features of the gulf of corinth are consequences of the motion of the south aegean and peloponnese as a single block late pliocene and quaternary geology and geomorphology indicate that the boundaries of the rigid blocks in central greece have changed over that time with faulting migrating into the hanging walls sometimes changing in orientation these changes are probably related to the way faulting in the seismogenic layer adapts to block rotation so as to maintain the general features of a velocity field that is controlled by larger scale effects such as buoyancy forces and the seaward migration of the subducting slab beneath crete the image of greece as a mosaic of rigid blocks whose boundaries change with time is a useful framework for seismic hazard evaluation but we emphasize that some moderate sized earthquakes do occur away from the main fault zones within the relatively rigid blocks and especially near their diffuse ends

gravity analysis over the aral black and caspian seas from a combined geos 3 seasat geosat altimeter data set geos 3 seasat and geosat satellite altimetry data over the aral black and caspian seas are processed using least squares collocation to predict geoid undulations and free air gravity anomalies on a 0 25 0 25 grid a 180 180 geopotential model provides a reference surface for the collocation procedure and the framework for a regional map using local empirical covariance functions computed by an iterative numerical convolution technique prediction accuracies of 24 8 and 10 mgal were achieved for the aral black and caspian seas respectively over the caspian sea a hybrid theoretical empirical covariance function was used to obtain reliable short wavelength gravity anomalies the resulting regional gravity anomaly map confirms tectonic structures postulated by other investigators reveals gravitational evidence of river sediments and generally improves our knowledge of the geophysics of inland seas

global statistical analysis of topex and poseidon data a global statistical analysis of the first 10 months of topex poseidon merged geophysical data records is presented the global crossover analysis using the cartwright and ray 1990 cr tide model and gaspar et al this issue electromagnetic bias parameterization yields a sea level rms crossover difference of 10 05 cm 10 15 cm and 10 15 cm for topex topex poseidon poseidon and topex poseidon crossovers respectively all geophysical corrections give reductions in the crossover differences the most significant being with respect to ocean tides solid earth tide and inverse barometer effect based on topex poseidon crossovers and repeat track differences we estimate the relative bias between topex and poseidon at about 15 5 1 cm this value is dependent however to the electromagnetic bias corrections used an orbit error reduction method based on global minimization of crossover differences over one cycle yields an orbit error of about 3 cm rms this is probably an upper estimate of the orbit error since the estimation absorbs other altimetric signals the rms crossover difference is reduced to 8 8 cm after adjustment a repeat track analysis is then performed using the cr tide model in regions of high mesoscale variability the rms sea level variability agrees well with the geosat results tidal errors are also clearly evidenced a recent tide model ma et al this issue determined from topex poseidon data considerably improves the rms sea level variability the reduction of sea level variance is 4 cm 2 on average but can reach 8 cm 2 in the southeast pacific southeast atlantic and indian oceans the rms sea level variability thus decreases from 6 cm to only 4 cm in quiet ocean regions the large scale sea level variations over these first 10 months most likely show for the first time the global annual cycle of sea level finally we analyze the topex and poseidon sea level anomaly wavenumber spectral characteristics topex and poseidon have identical spectral characteristics at low wavenumbers for wavelengths shorter than 100 km however poseidon spectra are more energetic this is probably related to the topex tracker characteristics and to the way the acceleration correction is made in the geophysical data records poseidon repeat track noise level is estimated at about 3 cm for a 1 s average the topex repeat track noise level is about 1 8 cm rms but this probably corresponds to averages over several seconds

fault structure and related basins of the north aegean sea and its surroundings 1 fault structure and basin evolution in the northern aegean sea and its surroundings have been investigated using bathymetry available onshore and offshore seismic profiles onshore fault patterns from ne greece nw turkey three islands in the aegean sea surface ruptures associated with the 1978 thessaloniki earthquakes gps measurements from north aegean islands and a number of earthquake focal plane solutions and historic seismicity bathymetric and isopach data show that the north aegean trough can be divided into the sporades basin and the saros trough post miocene sediment thickness differences in these basins offset of distinct horizons and frequent seismicity along basin bounding faults indicate that sediment accumulation in the area is fault controlled offshore seismic profiles show that the basin bounding faults are dominantly characterized by apparent normal components as well as strike slip components inferred from typical fault zone profiles additional evidence for existence of strike slip faulting comes from earthquake focal plane solutions we refined the pattern and kinematics of the faults controlling the basins and classified them into two major groups the faults in the first group trend ne sw and ene wsw and are here interpreted to be dominantly right lateral strike slip with normal or reverse components these faults accommodate a similar amount of deformation like the ganos fault and thus represent the westernmost extension of the north anatolian fault zone the faults in the second group trend nw se and are dominantly normal faults with an occasional left lateral component these faults are believed to manifest the termination of the north anatolian fault zone because of the segmentation of the right lateral strike slip faults and the preexisting ne trending tectonic grain the basins are compartmentalized into smaller depocenters basins are orientated with their long axes either parallel to the ne sw to ene wsw trending echelon strike slip faults or in the zone north of the strike slip faults parallel to the nw se trending normal faults the interpretations regarding the kinematics of the faults are consistent with the data compiled from the islands near the faults and from the land in ne greece and nw turkey the northern aegean basins and their spatial relationships to the fault architecture representing the diffused termination of the north anatolian fault system are consistent with the mechanical principles of the strike slip tectonics

westward propagation of the north anatolian fault into the northern aegean timing and kinematics we present new evidence for the propagation processes of the north anatolian fault folding in the dardanelles straits region allows us to document the timing of the deformation preceding and the finite displacement after the passage of the propagating tip of the fault the accuracy of the observations is due to interplay between deformation and the sea level changes in the mediterranean the well known messinian regression followed by the pliocene transgression the long term kinematics around the sea of marmara pull apart total displacement of about 85 km over the past 5 m y is similar to the present day kinematics deduced from space geodesy at a larger scale westward propagation of the north anatolian fault over nearly 2000 km in the past 10 m y appears to be associated with strain recovery suggesting that the continental lithosphere retains long term elasticity

assimilation of altimeter eddy fields in a limited area quasi geostrophic model abstract techniques for the synoptic analysis vertical inference dynamical adjustment and forecast of altimetric and deeper in situ data are presented as a first step towards the design of continuous assimilation schemes in limited area oceanic domains a year long time series of streamfunction maps denoted mark 2 drawn in the polymode area of the western north atlantic is used as a benchmark for various tests and simulations an original projection extension scheme using empirical modes of density and or pressure anomalies is used to obtain a first guess of the three dimensional structure of the currents starting from surface topography only in the mark 2 domain this technique works well since the first empirical mode is surface intensified and largely dominant an alternative approach is to incorporate deeper data e g float trajectories below the main thermocline the first guess currents are specified as initial and boundary condition of the harvard 6 level quasi geostrophic open ocean mode

the application of geodetic radio interferometric surveying to the monitoring of sea level summary under project iris international radio interferometric surveying geodesists are using very long baseline interferometry vlbi to monitor polar motion to 1 2 ms of arc and ut1 to 0 05 0 10 ms and to develop a global geodynamic network to detect and study centimetre level displacements of reference points associated with large scale phenomena such as tectonic plate motion and glacial rebound differential positioning techniques using the signals broadcast by the satellites of the global positioning system gps are being used to study finer scale phenomena such as localized subsidence and economically to relate these specialized surveys to the geodynamic network including tide gauge stations in this system will make it possible to detect motions of specific gauges and correct or delete the measurements from those gauges when computing changes in sea level the national oceanic and atmospheric administration noaa has selected several tide gauges on the east and west coasts of the united states and initial epoch gps surveys to tie the gauges to vlbi observations have already begun other countries participating in project iris are planning similar activities in addition to providing a globally based land reference datum for the tide gauge measurements the iris polar motion and ut1 time series may contribute directly to monitoring and interpreting global sea level changes changes in the volume and distribution of ice masses result in long term motions of the axis of rotation and sea level changes affect the length of day lod the iris time series will certainly have the resolution required to detect the expected polar motion and changes in lod and a properly designed global vlbi gps network should allow the ice sea level effects to be separated from crustal dynamics effects

simultaneous estimation of the gravity field and sea surface topography from satellite altimeter data by least squares collocation summary the signal content of seasat altimeter data is evaluated with respect to magnitude and wavelength based on this information covariance functions associated with the different signals errors have been determined the covariance function associated with the sea surface heights contains covariances associated with the geoid the stationary sea surface topography and the time varying sea surface topography these three components have been estimated from seasat altimeter data in the faeroe islands region using least squares collocation in the solution error covariances associated with errors in the orbits corrections for instrumental atmospherical and tidal effects and sea state related bias are taken into account the accuracies of the solutions are evaluated by computing error estimates and error correlations a special effort has been made to evaluate the correlations between the estimated geoid and the other signals errors the results show that geoid undulations may be estimated with an accuracy of 0 13 0 16m approximately 50 per cent of the error variance has a long wavelength signature which is mainly correlated with errors in the estimation of the permanent sea surface topography the short wavelength part of the error is mainly correlated with errors due to liquid water in rain and clouds free air gravity anomalies may be estimated with an accuracy of 8 8 11 7 times 10 5 ms 2 this error has a short wavelength signature which is mainly correlated with errors due to liquid water in rain and clouds however a comparison with gravity observations resulted in an agreement of 7 8 times 10 5 ms 2 both the permanent and the time varying sea surface topography may be estimated with accuracies of about 0 21 m

active faulting in the north eastern aegean sea islands abstract the distribution of seismicity faulting pattern and its effect on local geomorphology is examined for the islands of lemnos aghios efstratios lesvos chios samos and ikaria of north eastern aegean sea greece the main active faults on each island are described in terms of their geometrical characteristics and geomorphology faults that comply with specific criteria geological age effect on relief their geometrical relationship to the active stress field have been characterized as active we evaluated and reviewed published information augmented with new field data for onshore faults while the effects of faulting on the sea floor and their probable association with recorded earthquakes were used to determine offshore faulting the relation of active faulting to the stress pattern has been examined as well it is shown that as the deformation changes gradually from transtensional in the north to extensional in the south so does the active faulting pattern the effect of the westernmost splays of the north anatolian fault zone the largest of which is the 300 km long north aegean trough is profound due to their close vicinity causing shearing in good agreement with the modeled principal displacement zone deformation pattern faulting in the area is controlled by the distance from the main dextral principal displacement zones the northern part of the area is directly affected by the north anatolian fault zone and its splays while this effect gradually weakens in the central and southern areas the geomorphology responds to this faulting causing the formation of fault parallel gulfs near lesvos and lemnos and fault defined shorelines in the rest of the islands ikaria exhibits a notable fault controlled tilted topography as the result of footwall uplift

first seasat altimeter data analysis on the western mediterranean sea within recent years a new satellite technique has been successfully developed for studying the oceans altimetry the seasat experiment presents a particular interest because of the great accuracy of the altimeter data though its capabilities are bounded by the accuracy of the trajectory restitution the altimetric signal variations result from both marine and tectonic effects the discrimination of which may be difficult in the present study on the western mediterranean sea the altimeter data processing the satellite trajectory and the geoid features are considered the satellite topography of the mediterranean sea surface shows irregularities which are 1 order of magnitude greater than the expected oceanic effects and so are mainly connected to the earth structure in fact in spite of neglecting the oceanic effects correlation with emerged land islands or immerged land bathymetry and also with main tectonic features can be seen in particular evidence exists for isostatic compensation of airy type in the continental margins and oceanic areas

interaction between trench retreat and anatolian escape as recorded by neogene basins in the northern aegean sea the evolution of the north aegean sea is studied through the development of three deep basins the north aegean trough the north skyros basin and the ikaria basin bathymetric data a 2d seismic dataset and the well investigated stratigraphic records of the onshore deep basins of northern greece and western turkey were used to make structural and seismic stratigraphic interpretations the study area shows two sharp unconformities that correspond to the eocene oligocene transition and the miocene pliocene shift these discontinuities were used as marker horizons for a more detailed structural and seismic stratigraphic interpretation resulting in the identification of several seismic units a general seismic signature chart was established using onshore basin stratigraphy and well data which was then used to constrain the ages of the different seismic units the main features observed in the basins are interpreted as 1 trans tensional growth patterns in pliocene and quaternary sediments that combine ne sw trending and steeply dipping fault zones that likely correspond to strike slip corridors and e w wnw ese trending normal faults 2 regional erosional truncations of miocene sediments likely related to the messinian salinity crisis msc 3 thick delta turbidite deposits of neogene age only the north aegean trough shows evidence of earlier development and polyphase deformation through inversion structures and additional seismic units extension processes in the aegean region have been driven by the hellenic slab rollback since the middle eocene the widespread development of neogene basins at the whole aegean scale attests to a major tectonic change due to an acceleration of the trench retreat in the middle miocene the present study shows that the neogene basins of the north aegean sea developed in dextral transtension with the northward migration of the associated ne sw trending strike slip faults at regional scale this tectonic pattern indicates that the westward escape of anatolia started to interact with the trench retreat in the middle miocene around 10 myr before the arrival of the north anatolian fault in the north aegean sea

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

north aegean crustal deformation an active fault imaged to 10 km depth by reflection seismic data three multichannel seismic profiles imaged a normal fault to at least 10 km depth in the north aegean trough and thermaikos basin the fault is active and recent forming a scarp at sea bottom and crossing the quaternary deltaic front on the northern slope of the trough controlled to the south by the north anatolian fault prestack depth migration imaged the fault as a seismic reflector cutting steeply across the sedimentary rocks and flattening in the basement from the seismic image the n100 e strike of the fault scarp and the orientations of the three profiles the true fault dip is constrained to an average 20 in the basement a low angle dip the throw and age estimated from the geometry in the sedimentary rocks document recent onset of the motion that must have occurred at a high rate both the direction and the rate of slip are consistent with the instantaneous motion as measured by space based geodesy which shows the fault to be forming by pure normal slip large earthquakes that have occurred in the basin may relate to such normal faults whereas the north anatolian fault with its current strike slip earthquakes appears to slip here under low resolved shear stress

subsurface seepage of seawater across a barrier a source of water and salt to peripheral salt basins many of the great phanerozoic salt basins share a common paleogeography in which a deep lake or sea is separated from the ocean by a narrow barrier examples include the aptian evaporites of the south atlantic rift basins and the messinian salt deposits of the mediterranean sea and the north caspian depression marine transgressions over the barrier have been proposed as the origin for saline conditions in these basins we test an alternate hypothesis that subsurface seepage of seawater through the barrier was a significant source of water influencing both water level and water composition our model permits flux of water and salt into and out of the basin via 1 seepage through the barrier 2 evaporation from the water surface 3 rainfall and or rivers and 4 incorporation into basin sediments our investigation focuses on three settings a modern analog in the gregory rift of northern kenya the messinian mediterranean basin and the early cretaceous aptian salt basins of the south atlantic we test our model through a numerical simulation applying reasonable values for the dimensions of the barrier differences in water level and hydraulic conductivities to calculate flow rates through the barrier modeling results indicate that flux of seawater through a barrier to a peripheral basin ranges from the dominant component of lake water to insignificant depending on the climate size of the peripheral basin and hydraulic conductivity of the barrier the flux of salt is significant over the full range of modeled hydraulic conductivities producing brines in the peripheral lake and or sea within 0 5 m y in most cases this demonstrates that seepage through the barrier can account for lithologic and organic geochemical evidence for saline water conditions and that marine transgressions across the barrier are not necessary to explain the apparent high salinities

gravity anomalies and sea surface heights derived from a combined geos 3 seasat altimeter data set gravity anomalies and sea surface heights have been computed on a 0 125 grid in the ocean areas from a combined geos 3 seasat altimeter data set the basic estimation procedure used least squares collocation where model covariance functions are tailored to individual areas through altimeter residual variance scaling preliminary tests led to production prediction procedures using a reference model defined by a set of potential coefficients complete to degree 180 comparisons of the predicted anomalies with ship derived values showed agreement varying from 9 to 30 mgal no correction to the altimeter implied sea surface heights was made for sea surface topography effects the maximum anomaly predicted is 396 mgal near hawaii and the most negative anomaly is 361 mgal over the puerto rican trench the actual resolution of the predicted quantities was estimated to be about 0 19 based on a power spectrum analysis the resolution is limited by our data selection process which uses 300 data points from a thinned altimeter data set for the prediction of the 0 125 in a 3 3 block with one data selection and matrix inversion the predicted data are used to compute 104 potential coefficient spectrums using flat earth approximations developed by forsberg the spectra were classified in terms of smooth mild or rough areas the great majority 78 of the spectra were in the smooth classification good agreement was found from spectra computed from topographically reduced land data and the mean ocean data up to degree 800 we found that the spectra decayed as l 3 6 as compared to the decay of l 3 implied by the kaula model the gridded data was used to compute 1 1 and 0 5 0 5 mean values the 1 mean anomalies were compared to terrestrial data where an rms difference of 7 mgal was found in comparing 10 139 values these new values have allowed us to identify 1 mean anomalies based on terrestrial estimates that are in substantial error

an experiment to invert seasat altimetry for the mediterranean and black sea mean surfaces summary the high accuracy mapping of the mean sea surface mss from satellite altimetry requires efficiency flexibility and mathematical transparency from the data analysis this paper argues that so does the least squares inverse method prior to the data inversion models of covariance functions are constructed for the expected residual mean sea surface relative to a starting map and for the various error sources in the data including the radial orbit errors instrument noise and sea height variability the unique optimum solution is then restored from the data in a single step analysis with formal error estimates and possibly local a posteriori covariances resolving kernels numerical experiments are performed to obtain the mediterranean and black sea mean surfaces by an inversion of the seasat altimeter data in our present computational environment the constraint raised by the cost of a run leads us to degrade the rigorous data analysis strategy owing to these limitations and to the assumed covariance models and data coverage the mss is mapped with an accuracy of 12121x1 for wavelengths greater than 335 km the supplementary error related to shorter scales is 70 cm the inverse mss solution is compared with another model computed at the bureau gravimetrique international in a classical way crossing arc analysis plus data filtering from geos3 and seasat then neglecting the dynamic heights of the sea circulation we invert the seasat data set to map the equivalent free air gravity anomalies the cross covariance used is consistently derived from the a priori power spectrum of the mss the gravity anomalies are recovered with an accuracy of 1 mgal moreover a large error of 25 mgal is expected from the smoothing of the shorter scales an external comparison made with the gravimetric map of torge weber wenzel 1983 broadly agrees with our formal error estimates several prospective specifications concerning the covariance models and the numerical procedure are drawn from these preliminary experiments and comparisons

the solar tides and the sun synchronism of satellite altimetry several days separate the consecutive overflights of a fixed geographical point by a geodesic satellite along the same track so that the semi diurnal and diurnal oceanic tides as measured by an on board altimeter will appear as low frequency oscillations of the ocean surface this was an argument against the sun synchronous satellite altimeters for the study of luni solar tides these constituents being rejected under the 2 cy year frequency or even in the steady sea surface however this simplified scheme should be drastically modified by the adjunction of supplementary informations supplied by other data e g from tide gauges hydrodynamical models or statistics here we only show that using the a priori spatial statistical properties of the tides in a total inversion of altimeter data the sun synchronous satellites may contribute to map the luni solar tides in particular the accuracy of a tidal inverse solution is little dependent on its apparent frequency and on the proximity of the other aliased tides

an estimate of global absolute dynamic topography abstract we estimate the absolute dynamic topography of the world ocean from the largest scales to a short wavelength cutoff of about 6700 km for the period july through september 1978 the data base consisted of the time averaged sea surface topography determined by seasat and geoid estimates made at the goddard space flight center the issues are those of accuracy and resolution use of the altimetric surface as a geoid estimate beyond the short wavelength cutoff reduces the spectral 1eakage in the estimated dynamic topography from erroneous small scale geoid estimates without contaminating the low wavenumbers comparison of the result with a similarly filtered version of levitus historical average dynamic topography shows good qualitative agreement there is quantitative disagreement but it is within the estimated errors of both methods of calculation

estimation of main tidal constituents from topex altimetry using a proudman function expansion tidal models for the main diurnal and semidiurnal constituents have been computed from topex altimeter data and a set of proudman functions computed numerically in the space defined by the ocean basins the accurate modeling of the ocean tides is necessary in order to interpret the height measurements of the ocean surface obtained from satellite altimeters it is also an interesting dynamical problem in its own right the surface height field due to any tidal constituent can be expanded in terms of the eigenfunctions of the velocity potential proudman functions with coefficients estimated in a least squares sense from a field of discrete data points obtained from altimetry tide gauges bottom pressure sensors etc the proudman functions constitute a mass conserving orthogonal basis their computation does not require any assumption concerning friction or energy dissipation only a numerical grid expressing the shape of coastline and the bathymetry of the ocean basins they have the space structure of standing waves and can be identified as the zero rotation gravitational normal modes they have to be evaluated numerically only once for each particular grid resolution in this investigation the proudman functions were computed by means of finite differences in spherical coordinates over a 2ox2 o grid covering most of the world s oceans for a total of 8608 degrees of freedom the data field used in this study consists of approximately 15 months of topex altimetry in the form of collinear differences results for the major semidiurnal and diurnal constituents m2 s2 n2 k2 k1 o1 p 1 and q1 have been obtained in terms of corrections to a priori values obtained by fitting schwiderski s 1980 models the new models goddard space flight center gsfc94a are tested at a set of ground truth data points these tests indicate substantial improvement for most of the constituents as compared with schwiderski s solutions use of gsfc94a results in a 7 8 cm reduction in the rms overlap difference of 15 5 cm the gsfc94a model yielded a mean rms sea surface variability of 7 9 cm compared with the 9 4 cm obtained when using schwiderski s model

45 m y of aegean crust and mantle flow driven by trench retreat the available seismic anisotropy data in the aegean shallow mantle and their relationship with crustal deformation are used for deciphering the lithosphere scale flow pattern driven by rollback of the hellenic subduction slab in the north and central aegean the directions of mantle seismic anisotropy trend parallel to stretching lineations in core complexes of the overlying crust suggesting that crust and mantle have undergone the same direction of flow at the scale of the entire aegean crustal extension is controlled by dextral rotation around a pole located at scutary pec albania that is related to the hellenic trench retreat the intensity of mantle anisotropy increases as a function of distance from the pole and of amount of rotation surface geology reveals that this rotating flow pattern resulted in strains accumulated since 45 ma a slab tear model is suggested to integrate the observed variations of geological events in time and space to subduction dynamics

global mean sea surface based upon the seasat altimeter data a mean sea surface map has been computed for the global ocean areas between 70 n latitude and 62 s latitude based upon the 70 day set of seasat altimeter data recorded in 1978 a combination of regional crossover adjustment techniques and a global reference surface using the best available geodetic parameters for seasat has formed the basis for the computation the overall rms value of the crossover residuals in the open ocean areas was 13 cm after the adjustment a contour map of the crossover residuals is very similar in nature to earlier contour maps of the collinear pass results for mesoscale variability the mean sea surface is presented in the form of a global contour map a 0 5 0 5 grid and a computerilluminated image

deciphering subduction from exhumation in the segmented cycladic blueschist unit central aegean greece the cycladic blueschist unit cbu represents the northern passive margin of the adria continental block and ophiolites that are the remnants of the pindos ocean which were affected by high pressure low temperature metamorphism in the blueschist and eclogite facies during the eocene prior to the lutetian the ophiolitic and margin units were thrust towards the sw inside a ne dipping subduction zone two subsequent exhumation stages are characterized by top to the ne senses of shear i from mantle depths to lower crustal levels before 37 ma which was accommodated by an extensional inversion of the vardar suture zone and ii from deep crustal levels to the near surface between 30 and 20 ma which was accommodated by the north cycladic detachment it is during this late stage of ductile exhumation that the central cyclades core complex was exhumed segmentation of the cbu by normal faults started at 12 ma as recorded by the low temperature thermochronometers and was coeval with block rotation and folding with ns trending axes which were predominantly controlled by the myrthes ikaria strike slip fault in the centre of the cyclades a map restoration of the cbu geometry prior to segmentation has been carried out using available structural and paleomagnetic data the restoration shows that following the cbu exhumation from mantle depths to crustal levels a single core complex was exhumed along a single ne dipping detachment

tectono stratigraphy of the neogene basins in western turkey implications for tectonic evolution of the aegean extended region abstract the western part of the aegean region includes several neogene basins containing volcano sedimentary successions the neogene basins located along the northern menderes extensional metamorphic complex memc were developed during the miocene as supra detachment basins they contain two distinct volcano sedimentary successions separated by a regional unconformity the basins located to the west of the memc were developed as strike slip basins and contain volcanic and sedimentary units getting younger from ne to sw with no remarkable unconformity available paleomagnetic studies in the aegean region suggest to us that the basins to the west of the memc were developed in response to southward clockwise rotational roll back of the aegean subduction zone the eastern margin of this rotational deformation is characterized on the surface by a large strike slip zone which is known as izmir balikesir transfer zone ibtz the sedimentary successions in the basins along the northern memc do not show southward younging and are interpreted to be developed in response to exhumation of the memc during the pliocene to quaternary e w trending grabens such as the gediz alasehir buyuk and kucuk menderes grabens were developed in response to tectonic escape accompanying the slab roll back process these grabens truncate the memc basins during this time strike slip deformation and associated sedimentation continued along the ibtz

marine gateway vs fluvial stream within the balkans from 6 to 5 ma since the discovery of calcareous nannofossils dinoflagellate cysts and planktonic foraminifers in deposits from the dacic basin intensive research has been performed in order to evidence which gateway this microplankton used to connect paratethys and the mediterranean prior and after the messinian salinity crisis msc such a gateway is also to be regarded at the origin of successive influxes of paratethyan organisms molluscs ostracods dinoflagellates into the mediterranean basin lago mare events observing that the i stanbul area usually proposed for this purpose was inefficient we examine the succession of marine well dated pre msc and post msc deltaic deposits through the balkans from northern greece to southern romania that constitutes a reliable candidate for such a marine corridor the origin of which was caused by the regional tectonic extension the reconstructed palaeogeography for high sea level episodes that encompassed the msc clarifies the context of the so called north aegean lake this marine gateway probably evolved as a powerful river during the peak of the msc contributing to the deposition of clastics in the hydrocarbon prinos field a tectonically controlled subsidence to the north and south of the skopje region caused the closure of such a gateway

global seafloor topography from a least squares inversion of altimetry based high resolution mean sea surface and shipboard soundings summary we present a new worldwide 1 16 1 16 map of seafloor topography computed from an iterative inversion combining altimetry measurements of the marine geoid and shipboard echo soundings from the global national geophysical data center ngdc database the input geoid data for this computation are derived from altimetry measurements of the sea surface height from the ers 1 geodetic mission and the geosat ers 1 and topex poseidon exact repeat missions to calculate the seafloor topography from sea surface height measurements it is necessary to take the regional isostatic compensation of the topographic load into account for that purpose we consider a model of elastic flexure of the oceanic lithosphere in which the elastic plate thickness increases with crustal age with the solution we provide an uncertainty map that reflects the uneven distribution of and errors in the data and uncertainties in the model parameters as well as the increase of the geopotential error with the deepening of the seafloor the bathymetric solution is compared with the smith sandwell s 1997 science 227 1956 1962 solution the root mean square difference between the two amounts to 350 m however the two maps agree within 150 m over 65 per cent of the ocean surface

shallow structure and recent evolution of the aegean sea a synthesis based on continuous reflection profiles abstract a dense grid of continuous seismic reflection profiles partly calibrated with drilling results has allowed construction of a structural outline of the entire aegean sea in the north aegean we observe a clear difference between the thickly sedimented northern margin basins and the steep slopes of the trough margin of the southern north aegean the trough itself comprises a series of separate tectonic depressions resulting from an apparent transtensional motion the central aegean consists of a complex tectonic puzzle caused by the prevailing extension incipient strike slip faulting sub parallel to the north aegean trough trend may however affect its eastern anatolian domain three main structural areas characterize the southern aegean comparable structural directions cut across this chiefly extensional basin but one fault system may be prevailing over the others depending on the area the central cretan sea results from the interaction of at least two distinct extensions these were superimposed on previous mostly e w structural trends generated during the inception of the southern hellenic subduction and led to the present day predominant sw ne trending extension as a hypothesis we propose that the overall late miocene present evolution of the aegean sea is directly dependent on two geodynamic processes to the southeast of the area collision between arabia and turkey leads to the lateral westward expulsion of the aegean continental crust and to the west hellenic subduction is still active

global positioning system constraints on plate kinematics and dynamics in the eastern mediterranean and caucasus we present and interpret global positioning system gps measurements of crustal motions for the period 1988 1997 at 189 sites extending east west from the caucasus mountains to the adriatic sea and north south from the southern edge of the eurasian plate to the northern edge of the african plate sites on the northern arabian platform move 18 2 mm yr at n25 5 w relative to eurasia less than the nuvel 1a circuit closure rate 25 1 mm yr at n21 7 w preliminary motion estimates 1994 1997 for stations located in egypt on the northeastern part of africa show northward motion at 5 6 2 mm yr also slower than nuvel ia estimates 10 1 mm yr at n2 4 e eastern turkey is characterized by distributed deformation while central turkey is characterized by coherent plate motion internal deformation of 2 mm yr involving westward displacement and counterclockwise rotation of the anatolian plate the anatolian plate is de coupled from eurasia along the right lateral strike slip north anatolian fault naf we derive a best fitting euler vector for anatolia eurasia motion of 30 7 0 8 n 32 6 0 4 e 1 2 0 1 myr the euler vector gives an upper bound for naf slip rate of 24 1 mm yr we determine a preliminary gps arabia anatolia euler vector of 32 9 1 2 n 40 3 1 1 e 0 8 0 2 myr and an upper bound on left lateral slip on the east anatolian fault eaf of 9 1 mm yr the central and southern aegean is characterized by coherent motion internal deformation of 2 mm yr toward the sw at 30 1 mm yr relative to eurasia stations in the se aegean deviate significantly from the overall motion of the southern aegean showing increasing velocities toward the trench and reaching 10 1 mm yr relative to the southern aegean as a whole

3 d modelling of seamount topography from satellite altimetry we develop a complete set of algorithms to perform 3d modelling of seamount bathymery from satellite altimetry the first stage of the data processing consists in gridding the geoid to account for the long wavelength errors geoid heights are first bias adjusted at cross overs then a collocation on a regular grid is performed accounting for the altimeter errors in a second stage geoid heights are converted into bathymetry no simplifying assumption on the shape and location of the bathymetry highs is necessary bathymetric uncertainties due to the data sampling and the parameters of the mechanical and crustal models are evaluated

environmental and depositional characteristics of diatomite deposit alayunt neogene basin kutahya west anatolia turkey this paper describes the geological depositional and environmental characteristics of diatomite the diatomite deposit is situated in the southern part of the alayunt kutahya basin samples of 18 diatomites and 12 host rocks were collected from four sedimentary profiles in the spring season basement rocks are paleozoic aged metamorphic rocks schist phyllite quartzite etc and mesozoic aged ophiolitic and complex rocks host rocks are rhyodacitic rhyolitic tuffite volcanic glass diatomite is composed of upper miocene upper pliocene aged diatom species diatomite shows layer morphology and lies on volcanic glass layer xrd characteristic peaks of diatomite show that it comprises dominantly of opal a silica whereas volcanic glass has opal ct constituent sem and npm photomicrographs indicate that diatomites are dominantly composed of benthic freshwater diatom species such as pinnularia microstauron pinnularia lundii pinnulariasubrostrata pinnularia brevicostata pinnularia tenuis pinnularia sp navicula eligensis fragilaria construens mastogloia braunii grunow melosira varians agardh surirellacapronii brebisson cymbella lanceoloata amphora venata gomphonema germainii gomphonema angustatum and rhapalodia gibba these species are general indicators of shallow paleolake environment and cool climate conditions due to the fluvial currents and climatic conditions lake water levels temperature and nutrient content fluctuated through the time chemical data obtained from 18 diatomite samples show that while silica is the bodybuilding material for diatomite over 89 sio2 al mg and fe contents of diatomite samples might be derived from clastic materials the concentration of al mg and fe decreases toward the lake center diatom genera sedimentary profile sections and mineralogic data suggest that diatomite deposited in lacustrine type freshwater shallow lake is associated with upper miocene aged extension tectonics physical and filtration tests along with environmental characteristics of diatomite suggest that calcined diatomite can be used for waste treatment processes in the filter aid industry

new imaging of the salinity crisis dual messinian lowstand megasequences recorded in the deep basin of both the eastern and western mediterranean through several examples we show that following sea level fall and marginal erosion during the messinian salinity crisis msc clastic inputs into the eastern and western mediterranean sea are not distributed evenly in space and time but are mainly limited to the lower section of the messinian salinity crisis depositional megasequence significant similarities around the basin allow us to propose a mediterranean messinian salinity crisis depositional episode that can be divided into two seismic megasequences the messinian lower megasequence mlm and the messinian upper megasequence mum their distinctive seismic facies correspond to systems tracts deposited during three main stages that represent a complete sea level cycle 1 a falling stage systems tract including mass transport deposits and forced regressive clinoforms deposited in in the early part of the falling stage and related to the increasing rate of relative sea level fall this stage is characterized by a marked shift in the depocenter towards the deep basins 2 an early lowstand characterized by massive clastic inputs from major messinian rivers the rhone nile and antalya gulf rivers or smaller river systems offshore south lebanon these clastics were deposited in an oversaturated basin as evidenced by the interfingering chaotic and transparent seismic facies of the messinian lower megasequence mlm 3 a late lowstand starting with rapid deposition of massive halite with no detrital inputs into the deep basin the upper part of the evaporites clearly onlaps the messinian erosional surface at the margins and is evidence for a transition between a late lowstand stage and an early transgressive stage these deposits belong to the messinian upper megasequence mum we interpret the transition between the two megasequences as the peak of the salinity crisis the end of the relative sea level fall and the maximum dispersal of sands into the deep mediterranean basins

comparison of geos 3 and seasat altimeter resolution capabilities a comparison is made between geos 3 and seasat altimeter data with regard to noise power spectral density psd derived geoid psd and short wavelength resolution at wavelengths greater than 450 km the noise psds for geos 3 and seasat are essentially the same and are attributed to mesoscale oceanographic effects at shorter wavelengths the noise spectra diverge because of the higher geos 3 instrument noise the average along track geoid psds are nearly identical between wavelengths of 4500 and 72 km the spectral coherence between repeat tracks shows that the short wavelength resolution of seasat data is 32 km and for geos 3 it is 60 km

coastal sea level trends from topex poseidon satellite altimetry and tide gauge data in the mediterranean sea during the 1990s a joint analysis of topex poseidon satellite altimetry and tide gauge data is used to estimate sea level trends along the mediterranean sea coast from 1993 january to 2002 february a generalized least squares gls method allows us to take into account the space time distribution of the data and their respective error budgets nearly optimal parameters of the covariance functions involved in the gls method are estimated at different scales of analysis using a trial and error method combined data time series are then reconstructed at 153 locations along the coast the basin wide averaged linear trend for the coastal area shows a sea level rise of 4 54 0 30 mm yr 1 compared to 4 28 0 30 mm yr 1 for the open ocean only i e a 0 26 0 16 mm yr 1 difference the error is smaller because the systematic error does not take part in the error budget which is quite significant at local scales the coastal linear trends ranges from 8 5 to 13 5 mm yr 1 which is much narrower than ranges found by other open sea studies 24 0 to 10 0 16 0 to 29 0 mm yr 1 however a detailed error budget shows that the largest estimation errors come from the spatial extrapolation of the sea level signal required when tide gauge and altimeter data are merged the second error source is the instrumental noise and the random noise generated by the littoral contamination on altimeter measurements and from the crustal motions that are contaminating the tide gauge signal at local scale it is estimated that 85 percent of the error on linear trends does not exceed 2 mm yr 1