imaging alpine crust using ambient noise wave equation tomography we present an improved crustal vs model and moho depth map using ambient noise wave equation tomography the so called ambient noise wave equation tomography is a method to invert seismic ambient noise phase dispersion data based on elastic waveform simulation which accounts for 3 d and finite frequency effects we use cross correlations of up to four years of continuous vertical component ambient seismic noise recordings from 304 high quality broadband stations in the alpine region we use model lsp eucrust1 0 obtained from traditional ambient noise tomography as initial model and we iteratively improve the initial model by minimizing frequency dependent phase traveltime differences between the observed and synthetic waveforms of rayleigh waves in the period range 10 50 s we obtain the final model after 15 iterations with 65 total misfit reduction compared to the initial model at crustal depth the final model significantly enhances the amplitudes and adjusts the shapes of velocity anomalies at moho and upper mantle depth the final model corrects an obvious systematic velocity shift of the initial model the resulting iso velocity moho map confirms a moho step along the external side of the external crystalline massifs of the northwestern alps and reveals underplated gabbroic plutons in the lower most crust of the central and eastern alps ambient noise wave equation tomography turns out to be a useful tool to refine shear wave velocity models obtained by traditional ambient noise tomography based on ray theory

new moho map for onshore southern norway a recent seismic refraction study across southern norway has revealed that the up to 2469 m high southern scandes mountains are not isostatically compensated by a thick crust rather the moho depths are close to average for continental crust with elevations of similar to 1 km evidence from new seismic data indicate that beneath the highest topography moho depths are around 38 40 km these measurements are similar to 2 km deeper than early estimates interpolated from coarsely spaced refraction profiles but up to 3 km shallower than receiver function estimates for the area moho depth variation beneath the mountains roughly correlates with changes in surface topography indicating that topography is at least to the first order controlled by crustal thickness however the highest mountains do not overlie the thickest crust and additional support for topography for example from flexural strength in the lithosphere low densities in the upper mantle or mantle dynamics is likely the relationship between topography and moho depth breaks down for the oslo graben and the fennoscandian shield to the east and north high density lower crustal rocks below oslo graben and increasing crust and lithospheric thicknesses below the fennoscandian shield may produce a negative correlation between topography and moho depth

constraints on the correlation of p and s wave velocity heterogeneity in the mantle from p pp ppp and pkpab traveltimes we investigate the correlation of large scale p and s velocity heterogeneity in the mantle by determining how well 106 000 compressional p pp ppp and pkpab traveltimes can be explained by s wave velocity model s20rts scaled using a depth dependent factor and by a model in which the lateral p velocity variations are different we first assess the assumption that p wave traveltimes can be explained by a model in which lateral p velocity variations p are identical to s velocity variations s in model s20rts for a given depth we project s from s20rts into model s2p using a depth dependent scaling factor r defined as s r z x p we find by grid search that the highest reduction of data variance is obtained when r increases linearly from 1 25 at the surface to 3 0 at the core mantle boundary a comparison of s wave ss and p wave pp traveltimes for identical source receiver pairs also indicates that r increases with depth significantly higher variance reduction is not obtained when r is parametrized with an additional degree of freedom therefore the precise shape of r cannot be constrained by our data p and pp wave traveltime anomalies with respect to the scaled model s2p yield coherent geographic variations this indicates that there are large scale lateral p velocity variations in the mantle that are different from those in model s2p we estimate these variations by inverting p wave traveltime anomalies with respect to model s2p for a degree 12 model of p velocity heterogeneity this model p 12 s 2 p indicates where in the well sampled mantle regions we need to modify model s2p to further improve the fit to the traveltime data anomalies in p12 s 2 p exist throughout the mantle it is therefore not obvious that compositional heterogeneity is prominent in the lower 1000 km of the mantle only as suggested previously low p wave velocities in the upper mantle beneath oceans are the strongest anomalies in p12 s 2 p and explain better the delayed traveltimes of pp wave phases with oceanic surface refection points lower mantle anomalies include high and low p velocity structures beneath eastern asia and north america respectively the high p velocity anomaly in the lower mantle beneath the central pacific is consistent with the assertion made by other researchers that large scale lower mantle upwellings are not purely thermal in origin

topographic expressions of mantle dynamics in the mediterranean abstract the surface of the earth is the ever changing expression of the dynamic processes occurring at depth and at or above its surface however our ability to read landscapes in terms of their underlying tectonic or climatic forcing remains rudimentary during the last decade particular attention has been drawn to the deep dynamic contributions to topography related to the stresses that are produced at the base of the lithosphere by mantle convection and their relevance compared to the iso static component of topography here we use examples from the mediterranean and estimate residual and dynamic topography we then compare those with surface uplift from geology for specific regions to disentangle the dynamic from the static components considering the different topographic signatures of tectonic processes e g actual residual and dynamic topography as well as uplift rates jointly provides a powerful way to distinguish between the contributions of mantle crustal and surface processes such an approach might bring us closer to reading topographic expressions in terms of their geological cause

ambient noise tomography of the pyrenees and the surrounding regions inversion for a 3 d vs model in the presence of a very heterogeneous crust we thank all participants in the fieldwork and the municipalities and landlords that hosted a pyrope temporary station we also acknowledge sismob the french seismic mobile pool a com ponent of the resif research facility for providing us with the seismological instrumentation for the temporary deployments we used data from the fr and rd resif g geoscope and ca institut cartogr afic i geol ogic de catalunya permanent net works resif http portal resif fr is a national research infras tructure recognized as such by the french ministry of higher education and research resif is managed by the resif con sortium composed of 18 research institutions and universities in france resif additionally supported by a public grant overseen by the french national research agency anr as part of the investissements d avenir program reference anr 11 eqpx 0040 andthefrenchministryofecology sustainabledevelopment and energy the pyrope experiment was supported by the french research agency anr blanc program project pyrope anr 09 blan 0229 this is a contribution of the team consolider ingenio 2010 topo iberia csd2006 00041 c

on crustal corrections in surface wave tomography summary mantle models from surface waves rely on good crustal corrections we investigated how far ray theoretical and finite frequency approximations can predict crustal corrections for fundamental mode surface waves using a spectral element method we calculated synthetic seismograms in transversely isotropic prem and in the 3 d crustal model crust2 0 on top of prem and measured the corresponding time shifts as a function of period we then applied phase corrections to the prem seismograms using ray theory and finite frequency theory with exact local phase velocity perturbations from crust2 0 and looked at the residual time shifts after crustal corrections residuals fall within the uncertainty of measured phase velocities for periods longer than 60 and 80 s for rayleigh and love waves respectively rayleigh and love waves are affected in a highly non linear way by the crustal type oceanic crust affects love waves stronger while rayleigh waves change most in continental crust as a consequence we find that the imperfect crustal corrections could have a large impact on our inferences of radial anisotropy if we want to map anisotropy correctly we should invert simultaneously for mantle and crust the latter can only be achieved by using perturbation theory from a good 3 d starting model or implementing full non linearity from a 1 d starting model

crustal structure of northern italy from the ellipticity of rayleigh waves abstract northern italy is a diverse geological region including the wide and thick po plain sedimentary basin which is bounded by the alps and the apennines the seismically slow shallow structure of the po plain is difficult to retrieve with classical seismic measurements such as surface wave dispersion yet the detailed structure of the region greatly affects seismic wave propagation and hence seismic ground shaking here we invert rayleigh wave ellipticity measurements in the period range 10 60 s for 95 stations in northern italy using a fully non linear approach to constrain vertical v s v p and density profiles of the crust beneath each station the ellipticity of rayleigh wave ground motion is primarily sensitive to shear wave velocity beneath the recording station which reduces along path contamination effects we use the 3d layering structure in mambo a previous model based on a compilation of geological and geophysical information for the po plain and surrounding regions of northern italy and employ ellipticity data to constrain v s v p and density within its layers we show that ellipticity data from ballistic teleseismic wave trains alone constrain the crustal structure well this leads to mambo e an updated seismic model of the region s crust that inherits information available from previous seismic prospection and geological studies while fitting new seismic data well mambo e brings new insights into lateral heterogeneity in the region s subsurface compared to mambo it shows overall faster seismic anomalies in the region s quaternary pliocene and oligo miocene layers and better delineates the seismic structures of the po plain at depth two low velocity regions are mapped in the mesozoic layer in the western and eastern parts of the plain which seem to correspond to the monferrato sedimentary basin and to the ferrara romagna thrust system respectively

upper mantle structure below the european continent constraints from surface wave tomography and grace satellite gravity data 1 we here exploit fundamental mode rayleigh and love seismic wave information and the high resolution satellite global gravity model ggm02c to obtain a 1 1 3 d image of a upper mantle isotropic shear wave speeds b densities and c density vscoupling below the european plate 20 n 90 n 40 w 70 e the 3 d image of the density vscoupling provides unprecedented detail of information on the compositional and thermal contributions to density structures the accurate and high resolution crustal model allows us to compute a reliable residual topography to understand the dynamic implications of our models the correlation between residual topography and mantle residual gravity anomalies defines three large scale regions where upper mantle dynamics produce surface expression the east european craton the eastern side of the arabian plate and the mediterranean basin the effects of mantle convection are also clearly visible at 1 the eastern sirt embayment 2 the west african craton northern margins 3 the volcanically active region of the canarian archipelago 4 the northern edge of the central european volcanic province and 5 the northeastern part of the atlantic ocean between greenland and iceland strong connections are observed among areas of weak radial anisotropy and areas where the mantle dynamics show surface expression although both thermal and additional dependencies have been incorporated into the density model convective down welling in the mantle below the east european craton is required to explain the strong correlation between the estimated negative mantle residual anomalies and the negative residual topography

hybrid broadband seismograms for seismic shaking scenarios an application to the po plain sedimentary basin northern italy the densely populated po plain a very deep sedimentary basin in northern italy is prone to heavy shaking during earthquakes seismic hazard assessment must account for local variation in wave amplification standard ground motion prediction equations may fail to picture the complexity of strong lateral gradients in seismic response due to sharp structural heterogeneity for this reason there is an increasing demand for full waveform predictions for engineering applications here we present an implementation of a hybrid broadband simulation based on the method of mai et al bull seismol soc am 100 6 3338 3339 2010 to obtain complete broadband seismograms of 0 1 10 hz with this method low frequency 1 hz and high frequency 1 10 hz seismograms are simulated separately using a deterministic and a stochastic method respectively we apply the method to four events recorded within the po basin with magnitude ranging from mw 4 4 to mw 5 6 the low frequency lf simulation is performed using specfem3d on a few test subsurface velocity models the three dimensional velocity model mambo molinari et al in bull seismol soc am 105 2a 753 764 2015 consisting of a detailed structural description of the basin based on extensive active source data embedded within a regional 3d crustal model provided the best results for broadband simulations that most closely corresponded with the observations it performed better than an ambient noise tomography model with more accurate s wave velocities but less well defined layer topographies emphasizing the importance of first order velocity discontinuities the high frequency hf seismograms are simulated using the multiple scattering approach of zeng et al j geophys res solid earth 96 b1 607 619 1991 the scattering coefficients are obtained by performing a non linear inversion for each station to find best fitting synthetic envelopes hf energy is then combined at sim 1 hz to match the amplitude and phase spectra of the lf signal we are able to simulate full waveforms throughout the po plain of which shaking duration matches observed data for stations located in the basin shaking amplitudes are generally overestimated in the low frequency simulation by the mambo velocity model updating the mambo velocity model with more accurate s wave velocity information of the ambient noise tomography model should improve the fit in future simulations

climatic transfer function from quaternary molluscs in european loess deposits abstract correspondence and multiple regression analysis of terrestrial molluscs in the loess sections of achenheim alsace france has permitted the reconstruction of climatic variations during the last three glacial interglacial cycles back to 339 000 yr b p the sequence has been dated according to the specmap chronology of imbrie et al 1984 and the fossil faunas have been calibrated in relation to recent assemblages sampled in defined ecological conditions in sweden and france transfer functions that relate the abundances of different species to climate allow the reconstruction of temperature and precipitation estimates for the coldest february and warmest august months in present day alsace were obtained and variations in temperature between 13 and 2 c in winter and 10 and 17 c in summer were determined these results are consistent with those yielded by transfer functions using other continental fossils estimates differ for past precipitation summer precipitation is always less than present with values between 50 and 78 mm while modern august values are 76 mm higher winter estimates are always higher than the present mean between 76 and 33 mm while the recent february value is 34 mm comparisons between cycles show that the climatic patterns described for one cycle cannot be strictly applied to the others comparisons have been made with the pollen stratigraphy of la grande pile the nearest quantified sequence to achenheim and with some atlantic cores in order to study the magnitude of deviations from modern mean values of the climatic parameters

crustal structure of iceland and greenland from receiver function studies 1 we used data from both permanent and temporary seismic networks on iceland and greenland to investigate the crustal thickness by partly reinterpreting earlier data p receiver functions and adding s receiver functions to better constrain the results we obtained good conversions from the moho and also crustal multiples in both iceland and greenland the central ice covered part of greenland has an average crustal thickness of 40 km typical for a craton at the edges of greenland the crustal thickness decreases to 30 40 km on the east coast of greenland where the track of the iceland plume is thought to have affected the lithosphere the crustal thickness is only 24 26 km in contrast to previous studies we find that the crustal thickness in the east and the northwest coastal regions of iceland is more than 40 km similar to beneath the active volcanic region in the southwest region of iceland and along the mid ocean ridge the crustal thickness is only 25 km or less also in contrast to earlier receiver function interpretations which deduced a broad crust mantle transition zone for iceland we find indications for a normal sharper moho beneath a number of sites

insights on upper mantle melting rheology and anelastic behavior from seismic shear wave tomography in seismic tomography we map the wave speed structure inside the earth but we ultimately seek to interpret those images in terms of physical parameters this is challenging because many parameters can trade off with each other to produce a given wave speed the problem is compounded by the convention of mapping seismic structures as perturbations relative to a 1 d reference model rather than absolute wave speeds using a full waveform tomography model of europe as a case study we quantify the extent to which thermochemical and dynamic properties can be constrained using only s wave speed expressed in absolute values the wave speed distributions of this tomography model are compared with 4 million thermochemical models whose seismic properties are computed via thermodynamic modeling these models sample the full range of realistic mantle compositions including variable water and melt contents and mineral intrinsic anelasticity is taken into account intrinsic anelasticity causes waves to travel more slowly at higher temperatures leading to seismic attenuation but the sensitivity of the wave speed reduction to temperature is in turn controlled by the wave frequency global studies of surface waves indicate an anticorrelation between s wave speed and attenuation we therefore only retain thermochemical models satisfying this anticorrelation our study indicates that the frequency dependence of anelasticity depends on temperature or rheology with 0 1 being most appropriate in cold or lithospheric mantle and 0 3 in warmer regions i e the asthenosphere additionally the slowest regions require specific compositions and or a velocity weakening mechanism such as partial melting elastically accommodated grain boundary sliding or water

significance of geological units of the bohemian massif czech republic as seen by ambient noise interferometry broadband recordings of 88 seismic stations distributed in the bohemian massif czech republic and covering the time period of up to 12 years were processed by a cross correlation technique all correlograms were analyzed by a novel approach to get both group and phase dispersion of rayleigh and love waves individual dispersion curves were averaged in five distinct geological units which constitute the bohemian massif saxothuringian tepla barrandean sudetes moravo silesian and moldanubian estimated error of the averaged dispersion curves are by an order smaller than the inherent variability due to the 3d distribution of seismic velocities within the units the averaged dispersion data were inverted for 1d layered velocity models including their uncertainty which are characteristic for each of the geological unit we found that overall the differences between the inverted velocity models are of similar order as the variability inside the geological units suggesting that the geological specification of the units is not fully reflected into the s wave propagation velocities on a regional scale nevertheless careful treatment of the dispersion data allowed us to identify some robust characteristics of the area the vp to vs ratio is anomalously low 1 6 for all the units the moldanubian is the most rigid and most homogeneous part of the bohemian massif middle crust in the depth range of 3 15 km is relatively homogeneous across the investigated region while both uppermost horizon 0 3 km and lower crust 15 km exhibit lower degree of homogeneity

kinematics seismotectonics and seismic potential of the eastern sector of the european alps from gps and seismic deformation data abstract we present a first synoptic view of the seismotectonics and kinematics of the eastern sector of the european alps using geodetic and seismological data the study area marks the boundary between the adriatic and the eurasian plates through a wide zone of deformation including a variety of tectonic styles within a complex network of crustal and lithospheric faults a new dense gps velocity field new focal mechanisms and seismic catalogues with uniformly re calibrated magnitudes from 1005 are used to estimate geodetic and seismic deformation rates and to develop interseismic kinematic and fault locking models kinematic indicators from seismological and geodetic data are remarkably consistent at different spatial scales in addition to large scale surface motion gps velocities highlight more localized deformation features revealing a complex configuration of interacting tectonic blocks for which new constraints are provided in this work accounting for elastic strain build up at faults bonding rotating blocks the geodetic and seismological data highlight two belts of higher deformation rates running wsw ene along the eastern southern alps esa in italy and e w in slovenia where deformation is more distributed the highest geodetic strain rates are observed in the montello cansiglio segment of the esa thrust front for which the higher density of the gps network provides indications of limited interseismic locking most of the dextral shear between the eastern southern alps and the eastern alps blocks is accommodated along the fella sava fault rather than the periadriatic fault in northern croatia and slovenia geodetic and seismological data allow constraining the kinematics of the active structures bounding the triangular shaped region encompassing the sava folds which plays a major role in accommodating the transition from adria to pannonian like motion trends the analysis of the seismic and geodetic moment rates provides new insights into the seismic potential along the esa front

wind driven ocean currents and ekman transport oceanographic engineering of the woods hole oceanographic institution and the massachusetts institute of technology woods hole ma 02543 oceanographers have long sought to verify the theoretical ekman transport relation which predicts that a steady wind stress acting together with the coriolis force will produce a transport of water to the right of the wind in situ measurements of wind and ocean currents provide a detailed view of this phenomenon by separating the wind driven current from the measured total current and by averaging over a long record it is found that the observed transport is consistent with theoretical ekman transport to within about 10 percent in this case the wind driven transport is strongly surface trapped with 95 percent occurring in the upper 25 meters as a result of fair summer weather

building and testing an a priori geophysical model for western eurasia and north africa we construct and evaluate a new three dimensional model of crust and upper mantle structure in western eurasia and north africa wena extending to 700 km depth and having 1 parameterization the model is compiled in an a priori fashion entirely from existing geophysical literature specifically combining two regionalized crustal models with a high resolution global sediment model and a global upper mantle model the resulting wena1 0 model consists of 24 layers water three sediment layers upper middle and lower crust uppermost mantle and 16 additional upper mantle layers each of the layers is specified by its depth compressional and shear velocity density and attenuation quality factors q p and q s the model is tested by comparing the model predictions with geophysical observations including crustal thickness surface wave group and phase velocities upper mantle n velocities receiver functions p wave travel times waveform characteristics regional 1 d velocities and bouguer gravity we find generally good agreement between wena1 0 model predictions and empirical observations for a wide variety of independent data sets we believe this model is representative of our current knowledge of crust and upper mantle structure in the wena region and can successfully be used to model the propagation characteristics of regional seismic waveform data the wena1 0 model will continue to evolve as new data are incorporated into future validations and any new deficiencies in the model are identified eventually this a priori model will serve as the initial starting model for a multiple data set tomographic inversion for structure of the eurasian continent

global crustal thickness from neural network inversion of surface wave data summary we present a neural network approach to invert surface wave data for a global model of crustal thickness with corresponding uncertainties we model the a posteriori probability distribution of moho depth as a mixture of gaussians and let the various parameters of the mixture model be given by the outputs of a conventional neural network we show how such a network can be trained on a set of random samples to give a continuous approximation to the inverse relation in a compact and computationally efficient form the trained networks are applied to real data consisting of fundamental mode love and rayleigh phase and group velocity maps for each inversion performed on a 2 2 grid globally we obtain the a posteriori probability distribution of moho depth from this distribution any desired statistic such as mean and variance can be computed the obtained results are compared with current knowledge of crustal structure generally our results are in good agreement with other crustal models however in certain regions such as central africa and the backarc of the rocky mountains we observe a thinner crust than the other models propose we also see evidence for thickening of oceanic crust with increasing age in applications characterized by repeated inversion of similar data the neural network approach proves to be very efficient in particular the speed of the individual inversions and the possibility of modelling the whole a posteriori probability distribution of the model parameters make neural networks a promising tool in seismic tomography

multi phase reactivations and inversions of paleozoic mesozoic extensional basins during the wilson cycle case studies from the north sea uk and the northern apennines italy

shaping mobile belts by small scale convection claudio faccenna and thorsten becker compute global mantle flow based on a recent high resolution seismic tomography model to investigate the role of buoyancy driven and plate motion induced mantle circulation for the mediterranean they show that mantle flow provides an explanation for much of the observed dynamic topography and microplate motion in the region and conclude that vigorous small scale convection in the uppermost mantle may also hold the key for understanding other complex mobile belts such as those in the north american cordillera and the himalayan tibetan collision zone here global mantle flow is computed on the basis of recent high resolution seismic tomography to investigate the role of buoyancy driven and plate motion induced mantle circulation in the mediterranean region the findings show that mantle flow explains much of the observed dynamic topography and microplate motion in the region small scale convection in the uppermost mantle may also hold the key to understanding complex mobile belts elsewhere mobile belts are long lived deformation zones composed of an ensemble of crustal fragments distributed over hundreds of kilometres inside continental convergent margins1 2 the mediterranean represents a remarkable example of this tectonic setting3 the region hosts a diffuse boundary between the nubia and eurasia plates comprised of a mosaic of microplates that move and deform independently from the overall plate convergence4 surface expressions of mediterranean tectonics include deep subsiding backarc basins intraplate plateaux and uplifting orogenic belts although the kinematics of the area are now fairly well defined the dynamical origins of many of these active features are controversial and usually attributed to crustal and lithospheric interactions however the effects of mantle convection well established for continental interiors5 6 7 should be particularly relevant in a mobile belt and modelling may constrain important parameters such as slab coherence and lithospheric strength here we compute global mantle flow on the basis of recent high resolution seismic tomography to investigate the role of buoyancy driven and plate motion induced mantle circulation for the mediterranean we show that mantle flow provides an explanation for much of the observed dynamic topography and microplate motion in the region more generally vigorous small scale convection in the uppermost mantle may also underpin other complex mobile belts such as the north american cordillera or the himalayan tibetan collision zone

long period body wave traveltimes through the crust implication for crustal corrections and seismic tomography summary the traveltimes of p and sh waves through the crust depend strongly on wave period at periods longer than 10 15 s where traveltime measurements for indirect e g surface reflected and core reflected waves are typically made the traveltimes are shorter than predicted by ray theory crustal corrections often used in global mantle tomography to isolate the effects of the crust on teleseismic traveltimes may have a complex frequency dependence and influence finite frequency inversions crustal corrections for profiles of crust2 0 and the prem reference model for the mantle may be several seconds larger or smaller than ray theoretical values depending on crustal thickness crustal velocities and wave period this variability is observed in the difference times between the seismic phases ss and s and between pp and p it is therefore important to incorporate the effects of the crust on traveltimes in finite frequency tomography in order to take full advantage of the variable mantle sensitivity of body waves at different periods

moho depth across the trans european suture zone from p and s receiver functions the mohorovicic discontinuity moho for short which marks the boundary between crust and mantle is the main first order structure within the lithosphere geodynamics and tectonic evolution determine its depth level and properties here we present a map of the moho in central europe across the teisseyre tornquist zone a region for which a number of previous studies are available our results are based on homogeneous and consistent processing of p and s receiver functions for the largest passive seismological data set in this region yet consisting of more than 40 000 receiver functions from almost 500 station besides we also provide new results for the crustal vp vs ratio for the whole area our results are in good agreement with previous more localized receiver function studies as well as with the interpretation of seismic profiles while at the same time resolving a higher level of detail than previous maps covering the area for example regarding the eifel plume region rhine graben and northern alps the close correspondence with the seismic data regarding crustal structure also increases confidence in use of the data in crustal corrections and the imaging of deeper structure for which no independent seismic information is available in addition to the pronounced stepwise transition from crustal thicknesses of 30 km in phanerozoic europe to more than 45 beneath the east european craton we can distinguish other terrane boundaries based on moho depth as well as average crustal v p v s ratio and moho phase amplitudes the terranes with distinct crustal properties span a wide range of ages from palaeoproterozoic in lithuania to cenozoic in the alps reflecting the complex tectonic history of europe crustal thickness and properties in the study area are also markedly influenced by tectonic overprinting for example the formation of the central european basin system and the european cenozoic rift system in the areas affected by cenozoic rifting and volcanism thinning of the crust corresponds to lithospheric updoming reported in recent surface wave and s receiver function studies as expected for thermally induced deformation the same correlation applies for crustal thickening not only across the trans european suture zone but also within the southern part of the bohemian massif

globsed updated total sediment thickness in the world s oceans we present globsed a new global 5 arc minute total sediment thickness grid for the world s oceans and marginal seas globsed covers a larger area than previously published global grids and incorporates updates for the ne atlantic arctic southern ocean and mediterranean regions which results in a 29 7 increase in estimated total oceanic sediment volume we use this new global grid and a revised global oceanic lithospheric age grid to assess the relationship between the total sediment thickness and age of the underlying oceanic lithosphere and its latitude an analytical approximation model is used to mathematically describe sedimentation trends in major oceanic basins and to allow paleobathymetric reconstructions at any given geological time this study provides a much needed update of the sediment thickness distribution of the world oceans and delivers a model for sedimentation rates on oceanic crust through time that agrees well with selected drill data used for comparison

practical earthquake location on a continental scale in australia using the ausrem 3d velocity model this study explores the full 3d earthquake location for the australian continent exploiting the recent 3d australian seismological reference model ausrem seismic velocities from ausrem were used as input to precompute finely spaced p and s travel time grids for each station in the australian national seismograph network using the multistage fast marching method travel times from anywhere in the grid to the corresponding station can then be computed by interpolation the location search using these travel times is based on matching observed and computed arrival times using the neighborhood algorithm all computations involved can be performed in practical time frames on a single processor computer the performance of the 3d approach relative to location using the 1d global ak135 velocity model was assessed by locating a set of recent earthquakes the arrival time residuals for p and s arrivals are significantly smaller when using the 3d ausrem model the improvements over ak135 are especially large in the 10 18 distance range in which a distance bias is strongly reduced and for those paths where the ak135 residuals are large a small set of six ground truth events was used to assess to what extent the reduction in travel time residuals leads to better absolute location accuracy the 3d location offset from the ground truth position is typically half that of the ak135 offset the patterns of offsets suggest that the already fast mantle wavespeeds in western australia need to be even faster than in ausrem

a three dimensional geophysical model of the crust in the barents sea region model construction and basement characterization summary barents50 a new 3 d geophysical model of the crust in the barents sea region has been developed by the university of oslo norsar and the u s geological survey the target region comprises northern norway and finland parts of the kola peninsula and the east european lowlands novaya zemlya the kara sea and franz josef land terminate the region to the east while the norwegian greenland sea marks the western boundary in total 680 1 d seismic velocity profiles were compiled mostly by sampling 2 d seismic velocity transects from seismic refraction profiles seismic reflection data in the western barents sea were further used for density modelling and subsequent density to velocity conversion velocities from these profiles were binned into two sedimentary and three crystalline crustal layers the first step of the compilation comprised the layer wise interpolation of the velocities and thicknesses within the different geological provinces of the study region linear relationships between the thickness of the sedimentary rocks and the thickness of the remaining crystalline crust are observed we therefore used the separately compiled area wide sediment thickness data to adjust the total crystalline crustal thickness according to the total sedimentary thickness where no constraints from 1 d velocity profiles existed the barents50 model is based on an equidistant hexagonal grid with a node spacing of 50 km the p wave velocity model was used for gravity modelling to obtain 3 d density structure a better fit to the observed gravity was achieved using a grid search algorithm which focussed on the density contrast of the sediment basement interface an improvement compared to older geophysical models is the high resolution of 50 km velocity transects through the 3 d model illustrate geological features of the european arctic the possible petrology of the crystalline basement in western and eastern barents sea is discussed on the basis of the observed seismic velocity structure the barents50 model is available at http www norsar no seismology barents3d

european mediterranean regional centroid moment tensor catalog solutions for years 2003 and 2004 abstract we present an update for years 2003 and 2004 of the european mediterranean regional centroid moment tensor rcmt catalog that we maintain since 1997 this update adds 177 new solutions to the database relating to moderate magnitude 4 5 m 5 5 earthquakes about 30 of our new solutions also appear in the global cmt catalog comparison of the two independent determinations generally shows very good agreement within the time span covered the most noticeable seismic sequences occurred in northern africa boumerdes algerian coast in 2003 and al hoceima morocco in 2004 and in southern greece and dodecanese region august 2003 and 2004 the complete rcmt catalog for the european and mediterranean region now covers 8 years and contains about 600 solutions

moho depth and vp vs ratio in peninsular italy from teleseismic receiver functions 1 we present a new data set of moho depth estimates for peninsular italy obtained from receiver functions analysis and a grid search approach teleseismic records from 174 broadband seismic stations were used to compute the receiver function data set in general our results agree well with previous knowledge adding original information in many regions where previous data were lacking or uncertain we find broad regions with consistent moho depth namely 1 the peri tyrrhenian areas bordering the homonymous sea have a 20 to 25 km deep moho 2 the foreland regions adriatic apulia iblean with 30 35 km deep moho 3 the apennines belt where we find westward deepening of the adriatic moho down to 50 km depth that well delineate the westward adria subduction overlayed by the shallow tyrrhenian moho 4 calabria shows a flat 40 km deep moho suddenly dipping at high angle from the tyrrhenian coast westward defining the ionian subduction and 5 a clear separation between northern and southern apennines is marked by a region of almost flat moho possible evidence of a detached slab in between we also find that in the northern apennines the shallow tyrrhenian moho is continuous for more than 200 km from the sea to under the northern apennines with a generally flat geometry and a few undulations suggesting either the boudinage or episodic pulses of extension of the tyrrhenian crust during its pliocene quaternary stretching the eastward extent of the tyrrhenian moho below the apenninic belt approximately corresponds to the eastward extent of the observed extension in the upper crust as mapped by the normal faulting earthquakes in this portion of the apennines we interpret an intracrustal discontinuity sw dipping below the belt parallel to the adria moho as the top of the lower crust being subducted beneath the apennines the subcrustal earthquakes of this region down to 80 km depth seem to be located within this subducted crustal layer the southern apennines show the same general geometry of subduction as the northern arc although the former have a less defined on land extended region and no earthquakes in the lower crust uppermost mantle in between the central apennines present a different moho geometry no clear doubling of the two plates but rather a constant bilateral deepening possibly associated to a crustal root with no evidence of a subduction setting this reinforces the hypothesis of a detached slab in this area we also present the first large scale mapping of average crustal vp vs ratios for peninsular italy the results although representing averages over the whole crust enhance some interesting features the most evident are belts of high vp vs in the thinned crust of the apennines where extension has long been active in the quaternary probably as an effect of highly fractured rocks with abundant fluid circulation strong correlation exists between areas of high vp vs and quaternary volcanoes suggesting the presence of fluids at depth

surface wave tomography in the european and mediterranean region summary we present a new surface wave tomographic study of the broad european and mediterranean region our goal is to enhance the resolution of previously published group velocity models using new data from european permanent seismic networks and a dense broad band array in northern apennines retreat we measure fundamental mode rayleigh and love wave group velocities from long period seismograms recorded at regional distance between 600 and 7000 km our measurement technique is based on iterative application of multiple filters and phase matched filters we accurately estimate dispersion curves for more than 1500 rayleigh wave and about 850 love wave paths in the period range 35 170 s consistency of measurements is evaluated by comparing ray clusters from sample earthquakes to closely spaced retreat stations in the whole data set measurement errors in group velocity decrease with increasing distance and show to be caused by inaccuracy in the estimate of group arrival time we calculate maps of love and rayleigh group velocity at selected periods by linear tomographic inversion accounting for group arrival time errors and evaluating a posteriori group slowness errors data coverage in this region is not uniform and it is highly influenced by the uneven distribution of earthquakes and seismic stations we therefore build a laterally heterogeneous reference model by inverting a global data set of group velocity derived from the phase velocity library of ekstr

a crustal model for the eastern alps region and a new moho map in southeastern europe in the last two decades south central europe and the eastern alps have been widely explored by many seismic refraction experiments e g celebration 2000 alp 2002 sudetes 2003 although quite detailed images are available along linear profiles a comprehensive three dimensional crustal model of the region is still missing this limitation makes this region a weak spot in continental wide comprehensive representations of crustal structure to improve on this situation we select and collect 37 published active source seismic lines in this region after geo referencing each line we sample them along vertical profiles every 50 km or less along the line and derive p wave velocities in a stack of homogeneous layers separated by discontinuities depth of crystalline basement top of lower crust and moho we finally merge the information using geostatistical methods and infer s wave velocity and density using empirical scaling relations we present here the resulting crustal model for a region encompassing the eastern alps dinarides pannonian basin western carpathians and bohemian massif covering the region within 45 circ text 51 circ hbox n and 11 circ text 22 circ hbox e with a resolution of 0 2 circ times 0 2 circ we are also able to extend and update the map of moho depth in a wider region within 35 circ text 51 circ hbox n and 12 circ text 45 circ hbox e gathering moho values from the collected seismic lines other published dataset and using the european plate reference epcrust as a background all the digitized profiles and the resulting model are available online

epcrust a reference crustal model for the european plate summary we present a new crustal model for the european plate derived from collection and critical integration of information selected from the literature the model covers the whole european plate from north africa to the north pole 20 n 90 n and from the mid atlantic ridge to the urals 40 w 70 e the chosen parametrization represents the crust in three layers sediments upper crust and lower crust and describes the 3 d geometry of the interfaces and seismologically relevant parameters isotropic p and s wave velocity plus density with a resolution of 0 5 0 5 on a geographical latitude longitude grid we selected global and local models derived from geological assumptions active seismic experiments surface wave studies noise correlation receiver functions model epcrust presents significant advantages with respect to previous models it covers the whole european plate it is a complete and internally consistent model with all the parameters provided also for the sedimentary layer it is reproducible it is easy to update in the future by adding new contributions and it is available in a convenient digital format epcrust could be used to account for crustal structure in seismic wave propagation modelling at continental scale or to compute linearized crustal corrections in continental scale seismic tomography gravity studies dynamic topography and other applications that require a reliable crustal structure because of its resolution our model is not suited for local scale studies such as the computation of earthquake scenarios where more detailed knowledge of the structure is required we plan to update the model as new data will become available and possibly improve its resolution for selected areas in the future

crustal and upper mantle structures of makran subduction zone se iran by combined surface wave velocity analysis and gravity modeling abstract the inversion of rayleigh wave group velocity dispersion curves is challenging because it is non linear and multimodal in this study we develop and test a new rayleigh wave dispersion curve inversion scheme using the shuffled complex evolution sce algorithm incorporating this optimization algorithm into the inverse procedure not only can effectively locate the promising areas in the solution space for a global minimum but also avoids its wandering near the global minimum in the final stage of search in addition our approach differs from others in the model parameterization instead of subdividing the model into a large number of thin layers we invert for thickness velocities and densities and their vertical gradients of four layers sediments upper crust lower crust and upper mantle the proposed inverse procedure is applied to non linear inversion of fundamental mode rayleigh wave group dispersion curves for shear and compressional wave velocities at first to determine the efficiency and stability of the sce method two noise free and two noisy synthetic data sets are inverted then real data for makran region in se iran are inverted to examine the usage and robustness of the proposed approach on real surface wave data in a second step we applied 3d gravity modeling based on surface wave analysis results to obtain the density structure and thickness of each layer the reason for using both types of data sets is that gravity anomaly has a bad vertical resolution and surface wave group velocities are good for placing layer limits at depth but they are not very sensitive to densities therefore using gravity data increases the overall resolution of density distribution in a final step we used again the sce method to invert the fundamental mode rayleigh wave group dispersion curves based on the gravity results gravity results like thicknesses and sediment densities have been used to constrain the limit of search space in the sce method results show a high shear and compressional velocity under the gulf of oman which reduce to the north of the makran region the moho depth of the oman gulf is about 18 28 km and it increases to 46 48 km under the taftan bazman volcanic arc the density image shows an average crustal density with maximum values under the gulf of oman decreasing northward to the makran

three dimensional earthquake locations and upper crustal structure of the sannio matese region southern italy abstract the sannio matese region is one of the most seismically active regions of italy and has been struck by large historical earthquakes at present the area is characterized by low magnitude background seismicity and small seismic sequences following m 4 main events in this paper we show vp and vp vs models and 3d locations for a complete set of earthquakes occurring in the period 1991 2001 we observe a significant crustal heterogeneity with large scale east verging high vp fault related folds stacked by the pliocene compression the relocated earthquakes cluster along a 70 east dipping nw striking plane located at the border of the high vp thrust units normal fault earthquakes related to the young and active extension occur within these high vp zones interpreted as high strength material we expect large future earthquakes to occur within these high vp zones actually characterized by low magnitude seismicity at their borders

the crustal structure of the southern caspian region the south caspian basin appears to behave as a relatively rigid aseismic block within the otherwise deforming alpine himalayan orogenic belt this anomalous character suggests that there is a fundamental compositional difference between the crust of the south caspian basin and that of the surrounding region five new estimates of crustal velocity structure beneath the southern caspian region are determined by the teleseismic receiver function method these models show that the crust in turkmenia along the trend of the apshceron balkhan sill kopet dag mountains is 50 km thick in the southwestern part of the caspian basin the crust is 33 km thick and consists of a 13 km thick sedimentary section lying on a high velocity vp 7 1 km s 1 lower crustal section in the southeastern part of the basin the crust is 30 km thick and consists of a 10 km thick sedimentary section overlying a 20 km thick low velocity vp 5 8 km s 1 crystalline crust the receiver function models are combined with velocity models from previous russian deep seismic sounding studies into a 1800 km long ese wnw trending crustal cross section across the kura depression the south caspian basin and the kopet dag mountains the most significant features of this crustal model are the 20 km variation in thickness of cenozoic sedimentary basin deposits the absence of a granitic vp 5 8 6 5 km s 1 crustal layer in the central part of the south caspian basin and 20 km of crustal thinning beneath the central part of the basin the moho beneath the south caspian basin has a broad arch like structure whose western boundary is a relatively narrow zone across which the crust thins rapidly 20 km thinning over a 100 km zone and whose eastern boundary has a more gradual change in crustal thickness 20 km thinning over a 400 km zone the velocity depth profiles derived from the receiver functions are compared to laboratory velocity estimates made at pressures and temperatures appropriate for the lower crust in turkmenia but the seismic p wave data alone do not permit differentiation between the various possible rock types the crustal model developed for the south caspian basin is consistent with the hypothesis that the crystalline crust of the basin is a section of oceanic crust that is being overthrust by the continental crust around much of its margins however we cannot rule out the possibility that the crystalline crust beneath the basin is a section of lower continental crust whose upper crustal section has been removed by erosion or faulting

the moho depth map of the european plate summary the european plate has a 4 5 gy long and complex tectonic history this is reflected in the present day large scale crustal structures a new digital moho depth map is compiled from more than 250 data sets of individual seismic profiles 3 d models obtained by body and surface waves receiver function results and maps of seismic and or gravity data compilations we have compiled the first digital high resolution map of the moho depth for the whole european plate extending from the mid atlantic ridge in the west to the ural mountains in the east and from the mediterranean sea in the south to the barents sea and spitsbergen in the arctic in the north in general three large domains within the european plate crust are visible the oldest archean and proterozoic crust has a thickness of 40 60 km the continental variscan and alpine crust has a thickness of 20 40 km and the youngest oceanic atlantic crust has a thickness of 10 20 km

new insights into the structural model of the makran subduction zone by fusion of 3d inverted geophysical models abstract geological modeling by geophysical data in the makran subduction zone is a challenging task which comes from its extreme structural and geological complexity different geological models were presented for this zone in previous studies by the use of various sources of information among these studies numerous geophysical models were introduced to illustrate depth geometry and location of the subduction zone and definition boundaries with adjacent zones however structural complexity of the media and high degree of variation in geological units reduce accuracy of geophysical model derivation in this study an integrated strategy via model fusion for geological model building of the makran subduction zone was presented using gravity and magnetic data in the presented strategy gravity and magnetic models were integrated through fusing procedure herewith airborne magnetic and gravity data were inverted by fine gridding and solving large scale problems for each set of potential field data while magnetic model inherently was able to reveal near surface structures gravity data modeled large depth anomalies afterwards a discrete wavelet transform rule was used for fusion magnetic and gravity models to derive a unique model containing advantage of both sets of data the fused model revealed more detail of the makran zone structure location of the subduction zone and steep dip faults the final models proposed depth of 40 km for the top of the oceanic crust with variation in thickness from 5 to 8 km basin ward the subduction zone located 200 km in the onshore and it shows a very low dip

upper mantle and lithospheric heterogeneities in central and eastern europe as observed by teleseismic receiver functions summary data from 90 permanent broad band stations spread over central and eastern europe were analysed using ps receiver functions to study the crustal and upper mantle structure down to the mantle transition zone receiver functions provide valuable information on structural features which are important for the resolution of european lithospheric dynamics moho depths vary from less than 25 km in extensional areas in central europe to more than 50 km at stations in eastern europe craton and beneath the alpine carpathian belt a very shallow moho depth can be observed at stations in the upper rhine graben area ca 25 km whereas for example stations in the sw bohemian massif show a significantly deeper moho interface at a depth of 38 km vp vs ratios vary between 1 60 and 1 96 and show no clear correlation to the major tectonic units thus probably representing local variations in crustal composition delayed arrivals of converted phases from the mantle transition zone are observed at many stations in central europe whereas stations in the cratonic area show earlier arrivals compared with those calculated from the iasp91 earth reference model differential delay times between the p410s and p660s phases indicate a thickened mantle transition zone beneath the eastern alps the carpathians and the northern balkan peninsula whereas the transition zone thickness in eastern and central europe agrees with the iasp91 value the thickening of the mantle transition zone beneath the eastern alps and the carpathians could be caused by cold deeply subducted oceanic slabs

slab break offs in the alpine subduction zone after the onset of plate collision in the alps at 32 34 ma the deep structure of the orogen is inferred to have changed dramatically european plate break offs in various places of the alpine arc as well as a possible reversal of subduction polarity in the eastern alps have been proposed we review different high resolution tomographic studies of the upper mantle and combine shear and body wave models to assess the most reliable geometries of the slabs several hypotheses for the tectonic evolution are presented and tested against the tomographic model interpretations and constraints from geologic and geodetic observations we favor the interpretation of a recent european slab break off under the western alps in the eastern alps we review three published scenarios for the subduction structure and propose a fourth one to reconcile the results from tomography and geology we suggest that the fast slab anomalies are mainly due to european subduction adriatic subduction plays no or only a minor role along the tauern window sections possibly increasing towards the dinarides the apparent northward dip of the slab under the eastern alps may be caused by imaging a combination of adriatic slab from the dinaric subduction system and a deeper lying european one as well as by an overturned retreating european slab

active deformation and seismicity in the southern alps italy the montello hill as a case study abstract the montello anticline is a morphotectonic feature of the east pede mountain of the south alpine chain in northern italy which lies ca 40 km northwest of venice italy the purpose of this study is to characterize the present day crustal deformation and seismotectonics of the montello area through multi parametric geophysical observations we used new data obtained from the installation of a temporary network of 12 seismic stations and 6 gps sites the gps observations indicate that there is 1 mm yr shortening across the montello thrust sites located north of the montello thrust front deviate from the nnw ward adria eurasia convergence direction as they are constrained by a relative rotation pole in northwestern italy that has a nne ward motion trend over 18 months seismographic recordings allowed us to locate 142 local seismic events with ml 0 5 3 5 with good reliability rms 0 80 the source focal solutions indicate that i there is thrusting seismic activity on the basal sub horizontal portion of the montello structure and ii strike slip source kinematics prevail on the western edge of the montello hill our observations on the source mechanisms and the measured crustal deformation confirm that the montello thrust is tectonically active

crustal structure beneath the iberian peninsula and surrounding waters a new compilation of deep seismic sounding results abstract we present here an updated compilation of crustal parameters beneath the iberian peninsula and surrounding waters inferred from extensive deep seismic exploration performed in the last three decades firstly the more relevant experiments developed in both terrestrial and marine domains are revisited together with the corresponding seismic velocity depth models published that reveal the characteristics of the different tectonic domains sampled including oceanic zones continental margins orogenic and rift belts the results are summarized in three crustal transects sketched along representative directions secondly we compiled the moho depths along all the available seismic profiles to produce a geo referred database this database has then been interpolated using kriging algorithms to obtain a continuous moho depth model in the form of a regular grid file this integrative moho map for a key area in the western mediterranean documenting the interaction between european and african plates can contribute to constrain further regional studies either at crustal lithospheric or mantle scales

epmantle a 3 d transversely isotropic model of the upper mantle under the european plate summary we present a new 3 d transversely isotropic shear wave velocity model of the european and mediterraneanuppermantleobtainedbyanalysisofsurfacewaves datausedarefundamentalmode rayleigh and love group velocity measurements in the period range 35 170 s taken on seismograms recorded by european stations for regional earthquakes the tomographic inversion to map the 3 d earth structure is split into two steps first we regionalize the group velocity dispersion measurements obtaining distinct geographical group velocity maps at different periods then each local dispersion curve is inverted separately to find the shear wave velocity structure at depth the inversion benefits from using ap rioriinformation from a 3 d global mantle model s20rts and a new detailed european crustal model epcrust to constrain the shallower layers the inversion scheme follows a non linear iterative algorithm by which rayleigh and love group slowness are inverted simultaneously for the best fitting isotropic voigt shear wave speed 2 vsv 1 vsh and radial anisotropy parameter vsh vsv final merging of the vs profiles results in a new higher resolution 3 d model of european upper mantle we find that western europe and mediterranean sea are mainly characterized by relatively low velocities strongly contrasting with the fast roots of the eastern european craton many regional scale structures are also evident in the model thus providing insights into the complex geodynamic framework of the european continent most prominent are the low velocity west mediterranean spreading basins and european cenozoic rift system and seismically fast features connected to subduction of adria microplate hellenic arc and calabrian arc radial anisotropy does not vary very significantly with respect to the prem profile as available data only resolve lateral variations to a limited degree due to trade off with velocity epmantle has the potential to provide a reliable seismological reference for the upper mantle structure in the broad european region

european mediterranean regional centroid moment tensor catalog solutions for years 2001 and 2002 abstract we present regional centroid moment tensor rcmt solutions for 168 moderate magnitude earthquakes that occurred in the european mediterranean region during 2001 and 2002 events with moment magnitudes as low as 4 0 were successfully analyzed although this low threshold is only achievable in regions with the best azimuthal coverage and with stations at a few hundred kilometers distance earthquakes with focal depths from 10 to more than 200 km were analyzed comparison with standard harvard cmts when available shows good agreement the solutions shown in this paper represent an addition to the european mediterranean rcmt catalog that we are maintaining the rcmt catalog now spans 6 years from 1997 to 2002 and contains 420 solutions we also outline the main seismic sequences that occurred in the european mediterranean region during 2001 2002

the influence of nonuniform ambient noise on crustal tomography in europe 1 ambient noise seismology is of great relevance to high resolution crustal imaging thanks to the unprecedented dense data coverage it affords in regions of little seismicity under the assumption of uniformly distributed noise sources it has been used to extract the green s function between two receivers we determine the imprint of this assumption by means of wave propagation and adjoint methods in realistic 3 d earth models in this context we quantify the sensitivity of ambient noise cross correlations from central europe with respect to noise source locations and shear wave speed structure we use ambient noise recorded over 1 year at 196 stations resulting in a database of 864 cross correlations our mesh is built upon a combined crustal and 3 d tomographic model we simulate synthetic ambient noise cross correlations in different frequency bands using a 3 d spectral element method traveltime cross correlation measurements in these different frequency bands define the misfit between synthetics and observations as a basis to compute sensitivity kernels using the adjoint method we perform a comprehensive analysis varying geographic station and noise source distributions around the european seas the deterministic sensitivity analysis allows for estimating where the starting crustal model shows better accordance with our data set and gain insight into the distribution of noise sources in the european region this highlights the potential importance of considering localized noise distributions for tomographic imaging and forms the basis of a tomographic inversion in which the distribution of noise sources may be treated as a free parameter similar to earthquake tomography

eurid a regionalized 3 d seismological model of europe abstract this paper presents a 3 d regionalized model of the european crust and mantle velocity structure down to depths of approximately 300 km the model is entirely based upon the existing geological and geophysical literature and it incorporates topographic and bathymetric features the resulting model which we call eurid european i data set consists of approximately 6400 1 d vertical structures having an average separation of about 100 km eurid is compared quantitatively with eur s91 a recent s wave velocity tomographic model obtained from body and surface wave waveform inversion zielhuis a nolet g 1994 shear wave velocity variations in the upper mantle beneath central europe geophys j int 117 695 715 it is found that the s wave velocities in eurid and in eur s91 zielhuis and nolet 1994 do not differ by more than about 4 over most of the area to validate eurid surface wave dispersion analysis is performed along some selected paths the fundamental mode group velocity curves obtained using 1 d average models derived from eurid are found in good agreement with those determined from observations broadband waveform synthetics are also calculated along the same paths and compared with the observed time series overall we believe that eurid is representative of our current knowledge of the crust upper mantle structure beneath europe and it can be used to model realistically ground motion for periods above 10 s within structurally homogeneous regions the first digital version of this structure database is available for public use

lithosphere structure of european sedimentary basins from regional three dimensional gravity modelling abstract a three dimensional 3d density model approximated by two regional layers the sedimentary cover and the crystalline crust offshore a sea water layer was added has been constructed in 1 averaging for the whole european continent the crustal model is based on simplified velocity model represented by structure maps for main seismic horizons the seismic basement and the moho boundary laterally varying average density is assumed inside the model layers residual gravity anomalies obtained by subtraction of the crustal gravity effect from the observed field characterize the density heterogeneities in the upper mantle mantle anomalies are shown to correlate with the upper mantle velocity inhomogeneities revealed from seismic tomography data and geothermal data considering the type of mantle anomaly specific features of the evolution and type of isostatic compensation the sedimentary basins in europe may be related into some groups deep sedimentary basins located in the east european platform and its northern and eastern margins peri caspian dnieper donets barents sea basins fore ural trough with no significant mantle anomalies basins located on the activated thin crust of variscan western europe and mediterranean area with negative mantle anomalies of 150 to 200 10 5 ms 2 amplitude and the basins associated with suture zones at the western and southern margins of the east european platform polish trough south caspian basin characterized by positive mantle anomalies of 50 150 10 5 ms 2 magnitude an analysis of the main features of the lithosphere structure of the basins in europe and type of the compensation has been carried out

the distribution of moho depths beneath the arabian plate and margins abstract in this study three new maps of moho depths beneath the arabian plate and margins are presented the first map is based on the combined gravity model eigen 06c which includes data from satellite missions and ground based studies and thus covers the whole region between 31 e and 60 e and between 12 n and 36 n the second map is based on seismological and ground based gravity data while the third map is based only on seismological data both these maps show gaps due to lack of data coverage especially in the interior of the arabian plate beneath the interior of the arabian plate the moho lies between 32 and 45 km depth below sea level there is a tendency for higher pn and sn velocities beneath the northeastern parts of the plate interior with respect to the southwestern parts of the plate interior across the northern destructive margin with the eurasian plate the moho depths increase to over 50 km beneath the zagros mountains across the conservative western margin the dead sea transform dst moho depths decrease from almost 40 km beneath the highlands east of the dst to about 21 23 km under the southeastern mediterranean sea this decrease seems to be modulated by a slight depression in the moho beneath the southern dst the constructive southwestern and southeastern margins of the arabian plate also show the moho shallowing from the plate interior towards the plate boundaries a comparison of the abruptness of the moho shallowing between the margins of the arabian plate the conjugate african margin at 26 n and several atlantic margins shows a complex picture and suggests that the abruptness of the moho shallowing may reflect fundamental differences in the original structure of the margins

eucrust 07 a new reference model for the european crust 1 we present a new digital model eucrust 07 for the crust of western and central europe and surroundings 35n 71n 25w 35e available results of seismic reflection refraction and receiver functions studies are assembled in an integrated model at a uniform grid 15 0 15 0 the model consists of three layers sediments and two layers of the crystalline crust besides depth to the boundaries we provide average p wave velocities in the upper and lower parts of the crystalline crust the new model demonstrates large differences in the moho depth compared to previous compilations over 10 km in some specific areas e g the baltic shield furthermore the velocity structure of the crust is much more heterogeneous than in previous maps eucrust 07 offers a starting point for numerical modeling of deeper structures by allowing correction for crustal effects beforehand and to resolve trade off with mantle heterogeneities citation tesauro m m k kaban and s a p l cloetingh 2008 eucrust 07 a new reference model for the european crust geophys res lett 35 l05313 doi 10 1029 2007gl032244

tomography of the alpine region from observations of seismic ambient noise we use correlations of the ambient seismic noise to study the crust in western europe cross correlation of 1 year of noise recorded at 150 three components broadband stations yields more than 3 000 rayleigh wave group velocity measurements these measurements are used to construct rayleigh group velocity maps of the alpine region and surrounding area in the 5 80 s period band in the 5 10 s period band the seismic noise recorded in europe is dominated by surface waves originating from the northern atlantic ocean this anisotropy of the noise and the uneven station distribution affect the azimuthal distribution of the paths where we obtain reliable group velocity measurements as a consequence our group velocity models have better resolution in the northeast direction than in the southwest direction finally we invert the resulting rayleigh wave group velocity maps to determine the moho depth our results are in good agreement with the result of the numerous active experiments in the alps and provide a continuous image of the alpine structure