penetration of mid crustal low velocity zone across the kunlun fault in the ne tibetan plateau revealed by ambient noise tomography abstract the ne tibetan plateau composed of the mesozoic accretions of lhasa qiangtang and songpan ganze terranes are bounded by the east kunlun qaidam block in the north with the boundary delineated by the kunlun fault the ne tibetan plateau is at a nascent stage of plateau growth resulting from the collision between the indian and eurasian plate starting 50 million years ago and is one of the best areas to study the growth mechanism of the tibetan plateau in this study we process continuous ambient noise data collected from 280 stations during 2007 and 2010 and generate rayleigh wave phase velocity maps at 10 60 s periods with a lateral resolution of 30 50 km for most of the study region by adopting a bayesian monte carlo method we then construct a 3 d vsv model of the crust using the rayleigh wave dispersion maps our 3 d model reveals that strong lvzs exist in the middle crust across the ne tibetan plateau and the lateral distribution of lvzs exhibit significant west east variations along the kunlun fault in the west of 98 e lvzs are confined to regions of the kunlun fault and the eastern kunlun ranges but absent beneath the qaidam basin while in the east of 98 e lvzs extend and penetrate northward into the east kunlun and qinling orogens over 100 km across the kunlun fault the strong contrast of the lvzs distribution along the kunlun fault may be related to the distinct neighboring tectonic units in the north a strong crust of the qaidam basin in the west blocking the penetration of lvzs but a weak crust in the qinling orogens facilitating the extrusion of lvzs the distribution of lvzs in the ne tibetan plateau is consistent with the crustal channel flow model which predicts a branch of north eastward mid crustal channel flow our 3d model clearly delineates the north extent of the mid crustal lvzs probably reflecting the status of channel flow in the ne tibetan plateau

spaceborne tomography of multi species indian tropical forests abstract synthetic aperture radar sar backscatter is the coherent combination of the scattering from multiple individual scatterers within the radar resolution cell which results into a 2 d radar image tomographic sar tomosar takes advantage of multiple sar acquisitions to provide 3 d vertical structure of the imaged target over forests parameters such as canopy structure canopy density leaf area and phenology contribute to different sar scattering mechanisms along the vertical dimension of the trees tomography has been demonstrated in various earlier works for forest bio physical parameter estimation using airborne data in this research work multi polarimetric space borne tandem x tomograms are examined for the first time over a multi species indian tropical forest multiple tandem x acquisitions are focused using capon beamforming at five polarimetric channels hh hv vv hh vv and hh vv four distinct forest species compartments are selected representing different canopy structure and density the tomograms obtained in different polarizations for these species are analyzed in detail to understand the scattering patterns across different forest species field surveys carried out in several forest locations provide in situ observations of forest height and vertical structure it was observed that canopy gaps and leaf density play a crucial role for x band sar signal penetration through ground for dense canopy species the backscatter contributions are spread through the canopy while in case of sparse canopy species the ground scattering is dominant vertical profiles obtained at surveyed plot locations are plotted in all polarizations and provide a good agreement with field observations further the obtained tomosar backscatter layers have a good correlation with field measured above ground biomass agb the agb is modeled from tomosar with the hh pol tomosar backscatter layer at 27 m canopy height leading to an agb estimation with correlation r 0 76 and rmse of 50 4 t ha

tandem x pol insar performance for forest height estimation tandem x and terrasar x platforms form together the first spaceborne single pass polarimetric interferometer in space this allows for the first time the acquisition of spaceborne polarimetric synthetic aperture radar interferometry pol insar data without the disturbing effect of temporal decorrelation this paper aims to assess the potential of such data for forest applications for this single and dual pol data acquired over a boreal a temperate and a tropical site were investigated to characterize x band penetration and polarization diversity of the interferometric coherence measurements pol insar forest height inversion schemes have been proposed and implemented for the single and dual pol cases and cross validated against lidar reference measurements for all sites the single pol inversion relies on an external ground digital terrain model dtm and performed well for all sites with correlation coefficients r 2 between 0 80 and 0 98 the dual pol inversion does not require an external dtm but depends on the visibility of the whole forest layer accordingly its performance varied with forest structure and season the best performance was achieved for the summer acquisition of the boreal test site r 2 0 86 and for the winter acquisition of the temperate test site r 2 0 77 for the tropical test site only a weak correlation r 2 sim 0 50 could be established

the distribution of the mid to lower crustal low velocity zone beneath the northeastern tibetan plateau revealed from ambient noise tomography we collected continuous seismic data recorded between 2007 and 2010 by 208 broadband stations from the chinese provincial digital seismic networks a seismic collaborative experiment of northern tibet and the northeastern tibet seismic experiment cross correlations of vertical component records are computed to extract the rayleigh wave empirical green s functions group and phase velocities are then constructed from the empirical green s functions in 8 to 50 s period at periods 25 s more than 10 lower velocities are imaged beneath the qaidam basin and high velocities are observed beneath the nonbasin regions at periods 30 s up to 10 lower velocities are imaged in the qiangtang and songpan ganze terranes from these group and phase velocity maps a three dimensional 3 d vsv model of the crust is derived the model shows that the qiangtang and songpan ganze terranes have a very thick crust with a prominent low velocity zone lvz in the middle crust the lvz thins out in the vicinity of the eastern kunlun mountains providing a new constraint on the mode of deformation across the tibetan plateau the northwestern qilian orogen where receiver functions reveal a moho deeper than the surrounding areas also features a relatively weak midcrustal lvz which we interpret as an intracrustal response associated with the shortening between the north china craton and the tibetan plateau

forest height estimation by means of pol insar data inversion the role of the vertical wavenumber this paper examines the multifaceted effect of the effective spatial baseline as expressed through the vertical interferometric wavenumber on the inversion of forest height from polarimetric interferometric synthetic aperture radar pol insar data first the role of the vertical wavenumber in relating forest height to the interferometric volume coherence is introduced through the review of the forest height inversion from pol insar data the effect of the vertical wavenumber on the inversion performance is evaluated the selection of optimum with respect to forest height inversion performance vertical wavenumbers is discussed the impact of the acquisition geometry and terrain slopes on the vertical wavenumber and their consideration in the inversion methodology is addressed the individual effects discussed are demonstrated by means of airborne repeat pass pol insar acquisitions in l and p band acquired over different forest conditions including a boreal a temperate and a tropical forest test site the achieved forest height inversion performance is validated against reference height data derived from airborne lidar acquisitions

decorrelation in interferometric radar echoes a radar interferometric technique for topographic mapping of surfaces implemented utilizing a single synthetic aperture radar sar system in a nearly repeating orbit is discussed the authors characterize the various sources contributing to the echo correlation statistics and isolate the term which most closely describes surficial change they then examine the application of this approach to topographic mapping of vegetated surfaces which may be expected to possess varying backscatter over time it is found that there is decorrelation increasing with time but that digital terrain model generation remains feasible the authors present such a map of a forested area in oregon which also includes some nearly unvegetated lava flows such a technique could provide a global digital terrain map

density versus depth models from multimode surface waves multimode love and rayleigh wave data related to the pacific ocean and to north america are inverted using two sets of parameters 1 the isotropic p and s velocities plus the density and 2 five elastic parameters describing a transversely isotropic medium plus the density it is found that the assumption of isotropy leads to very unrealistic upper mantle models while much more realistic models are obtained under the assumption of transverse isotropy the lateral variations in density between the pacific ocean and north america are then less than 1 5 and in both regions a large density gradient is well resolved at a depth near 360 km

high resolution seismic imaging of outcrop scale channels and an incised valley system within the fluvial dominated lower freshwater molasse aquitanian western swiss molasse basin abstract high resolution seismic reflection surveys on lake geneva near lausanne switzerland allow the interpretation of outcrop scale sedimentary features within the fluvial dominated lower miocene lower freshwater molasse bedrock seismic modelling of an outcrop is used to calibrate the seismic data and assist with interpretation seismic resolution is sufficient to image sandstone channel fill complexes 4 5 m thick five seismic facies are recognized and interpreted as fluvial architectural elements of the lower freshwater molasse two of these facies are characterized by fairly continuous reflections of variable frequency and low to moderate amplitude interpreted as metre thick channel fill complexes the lateral extent of such channels ranges from 100 to 170 m the other three seismic facies are characterized by moderate to high amplitude sub parallel continuous reflections the three facies are mainly distinguished using reflection frequency and continuity they correspond to distinct floodplain settings i e proximal intermediate and distal with respect to the active channel belt on a larger scale a portion of a ca 50 m deep incised valley system probably caused by a relative base level fall was identified two distinct valley fill units are recognized the lower unit was interpreted as comprising valley edge slump units by comparison with outcrop data the upper unit is interpreted as the fluvial fill deposited in the most landward portion of the valley

wave theoretical inversion of teleseismic surface waves in a regional network phase velocity maps and a three dimensional upper mantle shear wave velocity model for southern germany summary using teleseimic surface wave data from 110 selected earthquakes recorded at 10broad band stations in southern germany we construct phase velocity maps of rayleigh waves for southern germany in a further step these maps are inverted for a three dimensional model of the sv velocity of the upper 200 km of the mantle we attempt to take into account the effect of heterogeneous structure outside the study region by jointly inverting the data for heterogeneous phase velocity inside the study region and the distortion of the incoming wavefields by the surrounding structure the total wavefield in the study region is computed with a scattering formalism which includes multiple forward scattering and single backscattering since in principle the data can be perfectly fit by the incoming wavefields without any heterogeneous structure inside the study area we impose additional constraints on the incoming wavefields to reduce the non uniqueness the most important constraint is an energy criterion which states that the energy of the modelled wavefield in the study area averaged over many events should be equal to the energy sampled by the stations we demonstrate that enforcing this criterion generates phase velocity maps with heterogeneous structure nevertheless we are able to satisfy the energy criterion without any heterogeneous structure at the price of an only slightly increased data misfit hence it must be concluded that a seismic network of size and station density such as the one used in this study is still insufficient to demonstrate convincingly the existence of heterogeneities in the network area using teleseismic surface waves any reasonable structure combined with the appropriate incoming wavefields would allow an acceptable fit of our data this frustrating conclusion of course applies to all other comparable studies which use teleseismic surface waves although we cannot convincingly show that any phase velocity map we find should be preferred over others we are able to obtain good reconstructions of test structures from realistic synthetic data with the same station and event distribution as the real data moreover we find that the geometric pattern of the phase velocity maps obtained from real data depends only weakly on the constraints applied in the inversion while the amplitude of the phase velocity perturbations is almost completely determined by the constraints for all periods considered the fit to the data is extremely good the reduction of the quadratic misfit relative to the case of plane incoming waves and no structure is dramatic for the shorter periods the 3 d model of vertical shear wave velocity down to a depth of 200 km exhibits a basic division into four quadrants separated by a vertical plane intersecting the surface along a nearly west east line and a horizontal plane at about 130 km depth the northern rants show high velocities in the top 120 km and low velocities below 140 km the opposite is the case for the southern quadrants an exception to this general feature is a pronounced low velocity zone in the northwestern corner of the region

wide band polarimetric radar inversion studies for vegetation layers the authors show how the entropy alpha target decomposition scheme may be used for parametric inversion studies on random particle cloud models for vegetation layers the decomposition is detailed first and then applied to a two parameter model for backscatter from a random cloud of small anisotropic particles the two main parameters used are the mean particle shape and the mean orientation angle of the cloud an inversion algorithm is presented and applied to broad band polarimetric radar data from the european microwave signature laboratory emsl joint research center ispra italy the results have been obtained from measurements of a fir tree and a ficus tree they show a wavelength scale dependence of the shape and distribution of scatterers which reflects the complex volume scattering nature of such problems moreover the values and trends from these two trees as a function of the frequency are different as expected from their physical structures consequently this algorithm has the potential to be useful in the construction of classification schemes for vegetation

two crustal low velocity channels beneath se tibet revealed by joint inversion of rayleigh wave dispersion and receiver functions abstract competing geodynamic models such as rigid block extrusion continuous deformation and the mid lower crustal flow have been proposed to describe the growth and expansion of eastern tibet however the dynamic processes responsible for plateau evolution and deformation remain poorly understood partly due to resolution limitations of previous models of lithospheric structure on the basis of joint inversion of rayleigh wave dispersion and receiver functions using data from a newly deployed seismic array we have obtained a high resolution 3d image that reveals the distribution of low velocity zones lvzs with unprecedented clarity the prominent feature of our model is two low velocity channels that bound major strike slip faults in se tibet and wrap around the eastern himalaya syntaxis consistent with the clockwise movement of crustal material in this region most large earthquakes in this region occurred in the boundaries of the lvzs we propose that ductile flow within these channels in addition to shear motion along strike slip faults played a significant role in accommodating intensive lithospheric deformation during the eastward expansion of tibet in the cenozoic

a temporal decorrelation model for polarimetric radar interferometers this paper describes a physical model of the temporal changes that occur in vegetated land surfaces observed by a repeat pass radar interferometer we assume the temporal changes to be caused by a gaussian statistic motion of the vegetation elements with motion variance changing along the vertical direction we show that the temporal correlation between two interferometric radar signals is affected by the structural parameters of the vegetation such as canopy height and varies with the wave polarization we validate the model using l band data acquired by the jet propulsion laboratory with the uninhabited aerial vehicle synthetic aperture radar airborne radar this work provides new insights into the role of temporal decorrelation in interferometric radar applications

uncertainty in well test and core permeability analysis a case study in fluvial channel reservoirs northern north sea norway reservoir permeability is one of the important parameters derived from well test analysis small scale permeability measurements in wells are commonly made using core plugs or more recently probe permeameter measurements upscaling of these measurements for comparisons with the permeability derived from drill stem tests dsts can be completed by statistical averaging methods dst permeability is commonly compared with one of the core plug averages arithmetic geometric or harmonic questions that commonly arise are which average does the dst derived permeability represent and over what region is this average valid another important question is how should the data sets be reconciled where there are discrepancies in practice the permeability derived from well tests is commonly assumed to be equivalent to the arithmetic in a layered reservoir or geometric in a randomly distributed permeability field average of the plug measures these averages are known to be members of a more general power average solution this pragmatic approach which may include an assumption on the near well geology is commonly flawed owing to several reasons that are expanded in this article the assessment of in situ reservoir permeability requires an understanding of both core plug and probe and well test measurements in terms of their volume scale of investigation measurement mechanism interpretation and integration this article presents a comparison of core and well test measurements in a north sea case study we undertook evaluation of three dsts and associated core plug and probe data sets from jurassic fluvial channel sandstones in a single field the well test permeabilities were generally found to differ from the core estimates begin page 1930 and no consistent explanation could be found for the group of wells however the probe permeameter data were able to further constrain the core estimates this study highlights the uncertainty in effective in situ reservoir permeability resulting from the interpretation of small core and reservoir well test scale permeability data the techniques used are traditional upscaling combined with the lorenz plot to identify the dominant flowing interval fluvial sandstones are very heterogeneous and this exercise is instructive in understanding the heterogeneity for the guidance of reservoir models in such a system

high resolution stratigraphy and seismic attribute mapping of a fluvial reservoir middle jurassic ness formation oseberg field continental successions of alternating fluvial reservoir sandstones and fine grained interfluvial deposits make hydrocarbon production planning and reservoir management difficult the vertical and lateral distribution of fluvial sandstones within the surrounding nonreservoir rocks in particular is a critical factor that needs to be investigated before production or injection wells can be successfully drilled in the oseberg field of the norwegian north sea about 21 7 million sm3 standard cubic meters of recoverable oil is stored within fluvial channel sandstones of the middle jurassic ness formation the ness formation reservoir is characterized by a relatively low proportion of good quality reservoir rocks approximately 30 of the total rock volume sedimentological studies indicate that reservoir sandstone bodies are developed mainly as elongate laterally restricted sandstone bodies concentrated within certain stratigraphic levels and geographic areas identifying and accurately mapping these sandstone rich intervals are important in defining possible drilling targets the distribution of reservoir rock within the upper ness formation has been the focus of detailed geological and three dimensional 3 d seismic mapping inverted seismic data integrated with geological well data give an empirical correlation between acoustic impedance and sandstone proportion in turn these relationships provide the basis for defining areas with a higher probability of encountering reservoir sandstone subsequent production drilling into the ness formation has confirmed the existence of reservoir sandstones within areas defined by the integration of high resolution stratigraphic mapping and the geophysical analysis the integration of sedimentological and 3 d seismic techniques presently offers the best potential for defining drilling targets within the ness formation in the oseberg field

estimation of the backscatter vertical profile of a pine forest using single baseline p band pol insar data the vertical backscatter profile of a pine forest constituted by stands of different height is inverted from a single baseline p band pol insar data in order to identify scatterers in the canopy the proposed approach uses the gaussian vertical backscatter profile model which associates an interferometric coherence expression to a vertical scatterers distribution characterized by relative standard deviation and elevation the methodology which uses in situ measurements of forest height and unbiased ground level estimation is applied to hv and vv channels providing accuracy given sufficiently low ground to canopy power ratios inverted backscatter profiles show maximum power converging toward the basis of the tree crown on highest forests where the largest branches are located indicating the high sensitivity of p band measurements to the forest structure and to the vertical biomass distribution over lower stands with larger tree densities the power peak is located in the upper part of the canopy which can be explained by a stronger attenuation in the canopy

reconstructing the architecture and sequence stratigraphy of the preserved fluvial record as a tool for reservoir development a reality check driven in part by the need for better information about fluvial systems for the purpose of nonmarine reservoir evaluation and development much valuable work is now being conducted on modern rivers and their deposits aided by such techniques as ground penetrating radar however studies of modern and recent systems cannot address the question of the long term preservability of the present day deposits only studies of the rock record itself can explore this issue two separate studies of ancient fluvial systems illustrate some of the problems a study of the hawkesbury sandstone triassic sydney basin australia highlighted the difficulty in interpreting the dimensions of large sand bodies from comparisons with a modern analog even when very large outcrops are available a seismic time slice study of pliocene pleistocene fluvial systems in the gulf of thailand revealed major changes in channel size and fluvial style over short vertical intervals braided and meandering systems meander belt widths 4 to 10 km 2 5 to 6 mi are separated by a few tens of meters of section or less and are interbedded with the deposits of much smaller rivers showing straight meandering and anastomosed patterns incised valleys and underfit streams are also present these variations can be interpreted in terms of a sequence model but they indicate the problems that could arise from the use of a single suite of dimensional variables as input into numerical reservoir heterogeneity and flow models most numerical simulation models make use of sets of equations relating such parameters as channel width depth and sinuosity but most such equations are generalized across the whole spectrum of fluvial styles and can be conditioned to the reality of individual reservoirs only with difficulty the application of the principles of sequence stratigraphy to fluvial deposits is rendered difficult by the complex response to allogenic forcing that characterizes fluvial systems episodes of aggradation and degradation that may be used to define sequences and their bounding unconformities in the stratigraphic record may be the result of the complex interplay of several allogenic mechanisms governing varying stream power and sediment supply mechanisms that may be operating at different time scales and may be out of phase with each other in developing practical solutions for reservoir development numerical modeling and simulation may provide generalized starting points for the analysis history matching commonly demonstrates inaccuracies in many initial models further progress may be made by direct study of the reservoir itself using three dimensional 3 d seismic and surveillance techniques there is a continuing role for the study of ancient analogs as providing a realistic database on the long term preservation styles of fluvial reservoir deposits

digital terrain surface and canopy height models from insar backscatter height histograms this article demonstrates how 3 d vegetation structure can be approximated by interferometric synthetic aperture radar insar backscatter height histograms single look backscatter measurements are plotted against the insar phase height and are aggregated spatially over a forest patch to form a 3 d histogram referred to as insar backscatter height histogram or simply insar histogram insar histograms resemble lidar waveforms suggesting that existing algorithms used to retrieve canopy height and ground topography from radar tomograms or lidar waveforms can be applied to insar histograms three algorithms are evaluated to generate maps of digital terrain surface and canopy height models gaussian decomposition quantile and backscatter threshold full polarimetric l band uninhabited aerial vehicle synthetic aperture radar uavsar data collected over the gabonese lope national park during the 2016 afrisar campaign are used to illustrate and compare the performance of the algorithms for the hh hv vv hh vv and hh vv polarimetric channels results show that radar derived maps using the insar histograms differ by 4 m top canopy 5 m terrain and 6 m forest height in terms of average root mean square errors rmses from standard maps derived from full waveform laser vegetation and ice sensor lvis lidar measurements

three dimensional lithospheric s wave velocity model of the ne tibetan plateau and western north china craton we present a new 3 d lithospheric vs model for the ne tibetan plateau netp and the western north china craton ncc first high frequency receiver functions rfs were inverted using the neighborhood algorithm to estimate the sedimentary structure beneath each station then a 3d vs model with unprecedented resolution was constructed by jointly inverting rfs and rayleigh wave dispersions a low velocity sedimentary layer with thicknesses varying from 2 to 10 km is present in the yinchuan hetao graben ordos block and western alxa block velocities from the middle lower crust to the uppermost mantle are generally high in the ordos block and low in the alxa block indicating that the alxa block is not part of the ncc the thickened crust in southwestern ordos block and western alxa block suggests that they have been modified two crustal low velocity zones lvzs were detected beneath the kunlun fault kf zone and western qilian terrane qlt the origin of the lvz beneath the kf zone may be the combined effect of shear heating localized asthenosphere upwelling and crustal radioactivity the lvz in the western qlt representing an early stage of the lvz that has developed in the kf zone acts as a decollement to decouple the deformation between the upper and lower crust and plays a key role in seismogenesis we propose that the crustal deformation beneath the netp is accommodated by a combination of shear motion thickening of the upper middle crust and removal of lower crust

underlying topography estimation over forest areas using single baseline insar data in this paper a method for digital elevation model dem extraction over forest areas from single baseline interferometric synthetic aperture radar insar data is proposed the main idea of this method is that some backscattering variations which are linked to the geometrical structures of forest occur during the radar acquisition the time frequency analysis is used to retrieve these variations by dividing the synthesized sar image into multiple sar images in the fourier domain called sublook images then by interferometry the sublook images characterized by the same doppler bandwidth and acquired from spatially separated locations at either end of a baseline are used to estimate the sublook coherences and the above backscattering variations are converted into the variations of sublook coherences as a result the number of insar observations can be increased the sublook coherences are then interpreted by the two layer vegetation scattering model and are assumed to follow a near linear relationship in the complex plane the ground phase can then be estimated by linear regression of the sublook coherences the performance of the proposed method was validated by e sar l and p band sar data acquired over coniferous and tropical forests for the coniferous scenario the underlying dem estimated by the proposed method has a root mean square error rmse of 4 39 m which is slightly less accurate than the dem with an rmse of 4 07 m derived by the polarimetric line fit lf method but represents a significant improvement in dem accuracy over the hh insar method for the tropical scenario the dems derived by the proposed method and the polarimetric lf method are closer to the ground surface than those derived by the hh insar method and their mean ground height difference is 0 62 m the two experiments confirm that it is feasible to extract a dem by the proposed method which has a comparable performance in dem inversion to the polarimetric lf method and only requires single polarization insar data

magnetostratigraphy of the middle jurassic brent group in the oseberg oil field northern north sea abstract magnetopolarity stratigraphy of the brent group and the uppermost part of the dunlin group has been established in two well cores from the oseberg field well 30 6 7 and well 30 9 2 northern north sea palaeomagnetic analysis of thermal demagnetization results defines a series of normal and reverse magnetozones in both wells remanent coercivity analysis of these middle jurassic clastic sediments indicates a magnetomineralogy independent of grain size interpreted to be of diagenetic origin thus suggesting that the magnetization is of early post depositional origin integration with the existing palynostratigraphic framework results in the establishment of several isochronous horizons especially in the ness formation which suggests lateral continuity of magnetostratigraphic datum planes between the two wells at the oseberg field although the exact dating of the magnetozones is not established the combined application of magnetopolarity and biostratigraphy provides a stratigraphic framework of improved resolution for these rock formations

reconciling lithospheric deformation and lower crustal flow beneath central tibet a viscous region with deformable boundaries is used to model simultaneous crustal flow and lithospheric coupling in northern tibet this model suggests that 1 the deformation of northern tibet is different from that of southern tibet because of structural differences between the regions 2 the viscosity contrast between the crust and the mantle lithosphere is relatively small beneath northern tibet and 3 crustal flow is compatible with crust mantle coupling under these conditions

azimuthal anisotropy from array analysis of rayleigh waves in southern california summary direct detection of rayleigh wave azimuthal anisotropy is reported by applying an array analysis to broad band seismic data in southern california usa our approach has excellent resolution for frequencies between 30 and 60 mhz and good resolution between 10 and 30 mhz limitation from array size limits accuracy below 10 mhz and complicated wave propagation effects lead to difficulty above 60 mhz between 30 and 60 mhz azimuthal anisotropy of rayleigh wave phase velocity is detected cleanly phase velocity results show that the 2 components dominate the 4 components strength of anisotropy hovers around 1 per cent for the 2 components with standard error 1 of about 0 4 per cent fast axes orientations show stable orientation in the direction 110 clockwise from north and its opposite direction 290 depth sensitivity kernels for p wave and s wave anisotropy indicate that anisotropy is confined to depths in the upper 100 km and may even be to shallower depths we speculate that the fast axes alignment may be associated with a strong shearing process over the thickness of lithosphere due to obliquely collisional motions between the pacific plate and the north america plate in the region

the development of fluvial stochastic modelling in the norwegian oil industry a historical review subsurface implementation and future directions abstract fluvial sandstones are an important reservoir type for the petroleum industry in the late 1970 s and early 1980 s large hydrocarbon discoveries in the norwegian north sea in fluvial strata prompted the need for generating geologically meaningful stochastic object based models of fluvial deposits the aim of this focus was to allow the geologist to provide the reservoir engineers with a more realistic representation of permeability contrasts within channelised fluvial deposits by being able to use appropriate measurements from outcrop analogues as direct input data into the modelling software this initiative resulted in the development of a suite of geologically driven stochastic modelling algorithms supported by an extensive fieldwork program aimed at collecting stratigraphic and quantitative data from ancient outcrop analogues to support enhanced reservoir characterisation and geological modelling today these reservoirs are still important hydrocarbon producing fields with accurate reservoir description and 3d modelling capabilities playing a vital role in targeting remaining oil especially now that many of the fields on the norwegian continental shelf are past peak production and are in a decline phase as both computing capabilities and quantitative outcrop analogue studies have increased the understanding of and the ability to model fluvial reservoirs so have stochastic modelling techniques continued to provide the most suitable and robust means of building geologically realistic 3d reservoir models that incorporate increased geological understanding and heterogeneity complexity in the recent past a multitude of data such as seismic and production data have been used to condition the stochastic algorithms this review paper aims to outline the role of stochastic algorithms in building geologically realistic 3d fluvial reservoir models and highlight the success of these developments with case studies from both producing fields and ancient outcrop analogue studies finally the paper will allude to possible improvements in stochastic fluvial modelling and future directions in the modelling of fluvial petroleum reservoirs these include the use of physical or process based models high resolution near wellbore models and multi point statistics that allow for more realistic representations of heterogeneities of fluvial deposits at a variety of scales and by a variety of methods

forced regressions in a sequence stratigraphic framework concepts examples and exploration significance sequence stratigraphic concepts suggest that stratal geometries develop and are largely controlled by changes in relative sea level on the shelf lowstand deposits which form during falls and subsequent stillstands of relative sea level can be recognized by the presence of an unconformity at the base the isolated and basinward position relative to the previous shoreline and the abrupt seaward translation of shallow water and shoreline facies into the basin across an unconformity surface this seaward translation of facies and shoreline regression in response to relative sea level lowering is termed a forced regression a forced regression is independent of variations of sediment flux and is in contrast with normal regressions that occur in response to excess sediment flux relative to space available on the shelf i e accommodation forced regressions commonly are associated with a zone of sedimentary bypass subaerial exposure and possible fluvial erosion between the newly formed and preceding shorelines certain shelf sands previously interpreted as offshore or mid shelf sand bodies thus can be reinterpreted as stranded lowstand shorelines associated with forced regressions this alternative interpretation has economic significance insofar as it suggests different subsurface correlations and reservoir geometries with the potential for development of new play types and enhanced recovery in o der fields examples of forced regression can be observed at a variety of scales and ages several such examples include the modern east coulee fan delta and the lower cretaceous viking formation in alberta canada the quaternary rhone delta and the quaternary hudson valley system

rayleigh wave phase velocity maps of tibet and the surrounding regions from ambient seismic noise tomography ambient noise tomography is applied to the significant data resources now available across tibet and surrounding regions to produce rayleigh wave phase speed maps at periods between 6 and 50 s data resources include the permanent federation of digital seismographic networks five temporary u s program for array seismic studies of the continental lithosphere passcal experiments in and around tibet and chinese provincial networks surrounding tibet from 2003 to 2009 totaling 600 stations and 150 000 interstation paths with such a heterogeneous data set data quality control is of utmost importance we apply conservative data quality control criteria to accept between 5000 and 45 000 measurements as a function of period which produce a lateral resolution between 100 and 200 km across most of the tibetan plateau and adjacent regions to the east misfits to the accepted measurements among passcal stations and among chinese stations are similar with a standard deviation of 1 7 s which indicates that the final dispersion measurements from chinese and passcal stations are of similar quality phase velocities across the tibetan plateau are lower on average than those in the surrounding nonbasin regions phase velocities in northern tibet are lower than those in southern tibet perhaps implying different spatial and temporal variations in the way the high elevations of the plateau are created and maintained at short periods 20 s very high velocities are imaged in the tarim basin the ordos block and the sichuan basin these phase velocity dispersion maps provide information needed to construct a 3 d shear velocity model of the crust across the tibetan plateau and surrounding regions

late carboniferous cyclothems and alluvial paleovalleys in the sydney basin nova scotia cyclothems are documented for the first time in alluvial to coastal plain strata west phalian d to stephanian of the sydney basin nova scotia well developed cyclothems commence with an extensive carbonaceous lime stone or shale with a restricted marine biota that indicates maximal flooding succeeding gray detrital bay and lake fills with distributary channel deposits are overlain by stacked channel deposits paleovalley fills that mark an abrupt basinward facies shift and a profound change in alluvial style channel fills and red vertisols were deposited on an alluvial plain above the filled valleys and the paleovalley is equated with thick vertisols in adjacent inter fluve areas the cyclothems are capped by gray coastal deposits with economic coals agglutinated foraminifera are present in seat earths beneath the coals which formed as a result of a brief stillstand during transgression red mudstones pass laterally into gray detrital bay fills in regions of greater subsidence associated with faulted basement blocks poorly developed cyclothems are bounded by extensive but split coals and autogenic effects partially obscure allogenic patterns mean cyclothem duration approximates 200 ka

mapping the upper mantle three dimensional modeling of earth structure by inversion of seismic waveforms a method is presented for the inversion of waveform data for the three dimensional distribution of seismic wave velocities the method is applied to data from the global digital networks international deployment of accelerometers global digital seismograph network the selected data set consists of some 2000 seismograms corresponding to 53 events and 870 paths the moment tensors of the earthquakes are determined through an iterative procedure which minimizes the corrupting influence of lateral heterogeneity a global model is constructed for shear wave velocity expanded up to degree and order 8 in spherical harmonics and described by a cubic polynomial in depth for the upper 670 km of the earth s mantle although no a priori information is incorporated the model predictions reproduce much of what is known about the dispersion of mantle waves for example high phase velocities for shields low velocities at ridges and a strong degree 2 pattern for rayleigh waves since the method makes use of complete waveforms overtone data are also included it is shown that the model is reproducible in that substantially the same model can be constructed from each half of the total data set considered independently the model shows that shields and ridges are major features in the depth interval 25 250 km the ridges of the southern pacific and the larger shields persist to 350 km but the southeast indian rise is underlain by a high velocity anomaly at this depth as is much of the mid atlantic ridge at 450 650 km the major features are a broad region of high velocities incorporating south america much of the south atlantic and parts of west africa a broad region of low velocities in the central and eastern pacific high velocities in the western pacific and a low velocity anomaly beneath the red sea and the gulf of aden in the absence of a crustal correction degrees 2 and 3 show a high positive correlation with the geoid paradoxically this is largely destroyed when the distribution in crustal thickness is taken into account spherical harmonic degrees 4 7 show a significant negative correlation

the structure of oriented vegetation from polarimetric interferometry polarimetric radar interferometry is much more sensitive to the distribution of oriented objects in a vegetated land surface than either polarimetry or interferometry alone this paper shows that single baseline polarimetric interferometry can be used to estimate the heights of oriented vegetation volumes and underlying topography while at least two baselines are needed for randomly oriented volumes single baseline calculated vegetation height accuracies are in the range of 2 8 m for reasonable levels of vegetation orientation in forest canopies

finite strain calculations of continental deformation 2 comparison with the india asia collision zone numerical experiments on a thin viscous sheet model for deformation of continental lithosphere subjected to an indenting boundary condition yield distributions of crustal thickness of stress and strain rate and of latitudinal displacements that may be compared with observations in the india asia collision zone a simple indenting boundary condition applied to initially laterally homogeneous sheets obeying a power law rheology produces results that are in broad agreement with the observations provided that the power law exponent is three or greater and the sheet can support vertically integrated stress differences of 2 1013 5 1012 n m 1 in regions in front of the indenter under these conditions the calculated deformation shows accommodation of convergence primarily by crustal thickening to produce a plateau in front of the indenter palaeomagnetic data from india and tibet and the observed distribution of topography suggest that much of the post eocene convergence of india with asia has been taken up by deformation within asia that involved crustal thickening the principal difference between calculation and observation is the absence from the calculated strain rate fields of east west extension of the plateau in front of the indenting boundary the calculations show that once such a plateau is formed the buoyancy force associated with the crustal thickness contrast inhibits further thickening and the plateau strains at less than half the rate of its immediate surroundings seismically determined regional strain rates exhibit a similar distribution with the tibetan plateau straining at about one quarter the rate of the tien shan and ningxia gansu regions calculated principal compressive stress orientations and regional strain rates agree with the seismically determined quantities in the mongolia baikal tien shan tibet and ningxia gansu regions of asia to within the uncertainty of the latter the vertically integrated stresses that are calculated for the viscous sheet are comparable with those that can be supported by a theologically stratified continental lithosphere obeying laboratory determined flow laws we suggest that the thin viscous sheet model described in this paper and its companion gives a simple and physically plausible description of the observed deformation in central asia in this description the predominant mechanism of accommodation of continental convergence is diffuse crustal thickening with shear on vertical planes playing a subsidiary role once large crustal thickness contrasts have been established

development of rift basins illustrated by the structural evolution of the oseberg feature block 30 6 offshore norway the mesozoic tilted fault block in norwegian north sea block 30 6 containing the giant oseberg oil and gas field is used to illustrate basin development during the jurassic and cretaceous there is seismic evidence for an early rifting phase in the northern viking graben on which the jurassic cretaceous rifting phase early bathonian to berriasian is overprinted the oseberg structure is representative of other fault blocks bordering the northern viking graben axis planar normal faults and listric faults which were restricted to the rifting phase dominate both fault types exhibit syn fault sedimentation listric faulting is recognized on seismic sections by the differential tilting reverse drag antithetic faulting and a wedge shaped syn rift reflector package the initiation of rifting is dated by baselap onto pre rift reflectors and cessation is dated by an unconformity beneath the generally onlapping post rift sediments steeply dipping planar normal faults often active along previously established fault zones played a significant part in the post rift development of the basin the last movement on planar normal faults in the oseberg fault scarp becomes younger away from the rift axis and this produced the complex fault scarp visible on many seismic lines the topography defined by the post rift unconformity is a composite surface which formed in response to subsidence processes it is not the result of orogenic events such as the kimmerian 9orogeny9 footwall uplift associated with planar normal faults caused local unconformities in complex fault scarps and on fault block crests

forest height inversion using high resolution p band pol insar data in this paper a high resolution p band pol insar data set acquired by the airborne ramses system over pine forest stands of different height is investigated a significant penetration depth in all the polarimetric channels and a wide range of polarimetric phase center heights are observed attesting of an interaction of the radar waves with different forest structural elements the main objective of this paper concerns forest height inversion at p band first forest modeling assumptions are evaluated using a priori information such as ground level and forest height measurements the full extend of the forest height is shown to be responsible of the volume decorrelation and a significant orientation effect is clearly identified over the highest stands as a consequence the oriented volume over ground model ovog is determined to be the most appropriated model for the forest height inversion at p band the ground contribution is present in all the polarimetric channels due to the important penetration at this frequency to overcome this difficulty a time frequency optimization method based on sublook decomposition is developed to separate the pure ground and canopy contributions allowing forest height estimation with ovog with an rms error on the order of 2 m in the last section of this paper a sensitivity analysis of the inversion with respect to two important system parameters the signal to noise ratio and the resolution is presented leading to a discussion on the inversion robustness in spaceborne conditions where these system parameters are the most deteriorated as compared to airborne configurations

forest modeling for height inversion using single baseline insar pol insar data the random volume over ground rvog model has been extensively applied to polarimetric synthetic aperture radar interferometry pol insar data for forest height inversion the model assumes forest as a homogeneous volume of randomly oriented particles characterized by a constant extinction but does not take into account the forest vertical heterogeneity to which interferometric coherence is sensitive in order to integrate vertical heterogeneity in forest models two complementary models which take into consideration the forest natural structure are investigated through analysis of volume interferometric coherence the first model assumes a vertically varying extinction in the volume layer and the second model considers predominant contributions localized in a finite height interval modeled as a gaussian distributed backscatter the two forest models are compared with constant extinction rvog in the coherence and interferometric phase aspects finally the contribution of these new models for forest height inversion using the pol insar technique is discussed in the context of a two layer ground canopy medium

upper mantle structure in southern norway from beamforming of rayleigh wave data presenting multipathing summary a model for the upper mantle sv wave velocity under southern norway is obtained by depth inversion of the average phase velocity of the rayleigh wave fundamental mode in the area the average dispersion curve is obtained in the period range 22 200 s by beamforming of 190 rayleigh waves recorded by the magnus network a temporary regional network of 41 broad band stations resolution of the beamforming procedure is increased by deconvolving the original beams from the array response function using the lucy richardson algorithm in addition to an average phase velocity beamforming gives us some information concerning the nature of the incoming wavefield we detect deviations of the wave propagation direction from the great circle paths which commonly reach 10 at a period of 25 s for the teleseismic events the amplitude of the deviations decreases with increasing period and with decreasing epicentral distance as expected the phase velocity measured by beamforming does not show any correlation with the deviation from great circle path suggesting that deviation does not bias phase velocity measurements we detect also significant multipathing with characteristics that vary rapidly with frequency the obtained sv wave velocity profile clearly shows that southern norway is underlain by a low velocity zone in the upper mantle and does not have shield like characteristics despite its location in the baltic shield these findings support the hypothesis that the high topography of southern norway is sustained by anomalous upper mantle material

the influence of fault array evolution on synrift sedimentation patterns controls on deposition in the strathspey brent statfjord half graben northern north sea the dispersal and deposition of sediments in a rift basin are controlled by the sediment supply and the generation of accommodation space hence for the facies mosaic and depositional architecture of synrift sediments to be understood both these variables must be constrained subsurface data sets comprising three dimensional 3 d seismic and well data provide the opportunity to quantify the rates of sediment supply and accommodation generation for the duration of the extensional event and over an area of regional extent in this article we address the controls on synrift sedimentation through detailed analysis of a high resolution subsurface data set from the late jurassic northern north sea rift basin the sedimentation history in the study basin comprises four discrete stages intimately linked to the growth of the normal fault population the earliest stage of rifting is characterized by a distributed fault population comprising a large number of faults with low slip rates sediment supply outpaced tectonic subsidence at this time and rising eustatic sea level was the primary control on sedimentation as rifting progressed strain was localized onto a smaller number of active structures with higher displacement rates the basin developed a grabenlike geometry and the lateral propagation and linkage of fault strands controlled accommodation generation although the basin was flooded the rate of sediment supply remained high and largely kept pace with the rate of tectonic subsidence during the final two stages the fully linked half graben bounding fault was the only active structure in the basin the rate of sediment supply at this time was greatly exceeded by the rate of tectonic subsidence and the basin became underfilled significantly the final stage of the sedimentation history is characterized by large scale fault interactions that changed the fault controlled basin floor topography hence modified sediment dispersal and deposition we conclude that sediment dynamics and facies distribution in a rift can only be understood in the context of the coevally active fault population as the faults active at the close of a rift event are very different in location and character to those active during the initiation of rifting this further emphasizes the need to integrate structural sedimentary and stratigraphic studies in rift basins

c band repeat pass interferometric sar observations of the forest properties of ers 1 c band repeat pass interferometric sar information for a forested area are studied the intensity information is rather limited but including coherence and effective interferometric sar insar height more information about the forest parameters can be obtained via satellite such information is also important for correction of insar derived topographic maps coherence properties have been used to identify forested nonforested areas and the interferometric effective height of the forest determined by comparison to a dem of the area the authors have developed a model to relate basic forest properties to insar observations these show that the coherence and interferometric effective height of a forested area change between image pairs the model demonstrates how these properties are related to the temporal decorrelation and the scattering from the vegetation canopy and the ground surface gaps in the vegetation are found to be important in the characterization of boreal forests

single baseline polarimetric sar interferometry examines the application of single baseline polarimetric sar interferometry to the remote sensing and measurement of structure over forested terrain for this a polarimetric coherent scattering model for vegetation cover suitable for the estimation of forest parameters from interferometric observables is introduced discussed and validated based on this model an inversion algorithm which allows the estimation of forest parameters such as tree height average extinction and underlying topography from single baseline fully polarimetric interferometric data is addressed the performance of the inversion algorithm is demonstrated using fully polarimetric single baseline experimental data acquired by dlr s e sar system at l band

repeat pass sar interferometry over forested terrain repeat pass synthetic aperture radar sar interferometry provides the possibility of producing topographic maps and geocoded as well as radiometrically calibrated radar images however the usefulness of such maps and images depends on our understanding of how different types of terrain affect the radar measurements it is essential that the scene coherence between passes is sdcient in this paper we derive a general system model including both radar system and scene scattering properties the model is used to interpret measurements over a forested area where the scene coherence varies between 0 2 and 0 5 the coherence is found to be sensitive to temperature changes around 0 c but surprisingly insensitive to wind speed the interferometric height discontinuity at the forest to openfield boundary shows good agreement with in situ tree height measurements for a dense boreal forest but is observed to decrease for a less dense forest this suggests the possibility of estimating bole volume from the interferometric tree height and a ground dem the decrease of scene coherence over a dense forest with increasing baseline is also used to estimate the effective scattering layer thickness

love rayleigh wave incompatibility and possible deep upper mantle anisotropy in the iberian peninsula love and rayleigh wave phase velocities are analyzed with the goal of retrieving information about the anisotropic structure of the iberian lithosphere the cross correlation method is used to measure the interstation phase velocities between diverse stations of the iliha network at periods between 20 and 120 s despite the 2 d structure of the network the love wave data are too few to enable an analysis of phase velocity azimuthal variations azimuthal averages of love and rayleigh wave phase velocities are calculated and inverted both in terms of isotropic and anisotropic structures realistic isotropic models explain the rayleigh wave and short period love wave phase velocities therefore no significant anisotropy needs to be introduced in the crust and down to 100 km depth in the upper mantle to explain our data a discrepancy is observed only at long periods where the data are less reliable love wave data at periods between 80 and 120 s remain 0 15 km s faster than predicted by isotropic models explaining the long period rayleigh wave data possibilities of biases in the measurements due to interferences with higher modes are examined but seem unlikely a transversely isotropic model with 8 of s wave velocity anisotropy in the upper mantle at depths larger than 100 km can explain the whole set of data in terms of a classical model of mantle anisotropy this corresponds to 100 of the crystals perfectly oriented in the horizontal plane in a pyrolitic mantle this is a rather extreme model which predicts at time delay between 0 and 2 seconds for split sks

the geological evolution of the tibetan plateau the geological evolution of the tibetan plateau is best viewed in a context broader than the india eurasia collision zone after collision about 50 million years ago crust was shortened in western and central tibet while large fragments of lithosphere moved from the collision zone toward areas of trench rollback in the western pacific and indonesia cessation of rapid pacific trench migration 15 to 20 million years ago coincided with a slowing of fragment extrusion beyond the plateau and probably contributed to the onset of rapid surface uplift and crustal thickening in eastern tibet the latter appear to result from rapid eastward flow of the deep crust probably within crustal channels imaged seismically beneath eastern tibet these events mark a transition to the modern structural system that currently accommodates deformation within tibet

crustal structure of the northeastern margin of the tibetan plateau from the songpan ganzi terrane to the ordos basin abstract the 1000 km long darlag lanzhou jingbian seismic refraction profile is located in the ne margin of the tibetan plateau this profile crosses the northern songpan ganzi terrane the qinling qilian fold system the haiyuan arcuate tectonic region and the stable ordos basin the p wave and s wave velocity structure and poisson s ratios reveal many significant characteristics in the profile the crustal thickness increases from northeast to southwest the average crustal thickness observed increases from 42 km in the ordos basin to 63 km in the songpan ganzi terrane the crust becomes obviously thicker south of the haiyuan fault and beneath the west qinlin shan the crustal velocities have significant variations along the profile the average p wave velocities for the crystalline crust vary between 6 3 and 6 4 km s beneath the songpan ganzi terrane west qinling shan and haiyuan arcuate tectonic region p wave velocities of 6 3 km s are 0 15 km s lower than the worldwide average of 6 45 km s north of the kunlun fault with exclusion of the haiyuan arcuate tectonic region the average p wave velocity is 6 4 km s and only 0 5 km s lower than the worldwide average a combination of the p wave velocity and poisson s ratio suggests that the crust is dominantly felsic in composition with an intermediate composition at the base a mafic lower crust is absent in the ne margin of the tibetan plateau from the songpan ganzi terrane to the ordos basin there are low velocity zones in the west qinling shan and the haiyuan arcuate tectonic region the low velocity zones have low s wave velocities and high poisson s ratios so it is possible these zones are due to partial melting the crust is divided into two layers the upper and the lower crust with crustal thickening mainly in the lower crust as the ne tibetan plateau is approached the results in the study show that the thickness of the lower crust increases from 22 to 38 km as the crustal thickness increases from 42 km in the ordos basin to 63 km in the songpan ganzi terrane south of the kunlun fault both the conrad discontinuity and moho in the west qinling shan and in the haiyuan arcuate tectonic region are laminated interfaces implying intense tectonic activity the arcuate faults and large earthquakes in the haiyuan arcuate tectonic region are the result of interaction between the tibetan plateau and the sino korean and gobi ala shan platforms

the structural evolution of the northern viking graben and its bearing upon extensional modes of basin formation recent advances in the understanding of rift basin formation coupled with the increasing public availability of seismic and well data across the northern viking graben 60 61 n have enabled a detailed analysis of its development two rifting episodes can be recognized late permian early triassic and bathonian ryazanian major regional unconformities thought to be primarily tectonic rather than eustatic in origin separate and subdivide the rifting episodes the earlier episode involved extension about a n s axis ensuing triassic mid jurassic thermal subsidence was accommodated on steep faults during the later episode a new ne sw fault trend was superimposed on pre existing patterns major block rotation marking active rifting ceased at the end of the ryazanian during the second post rift episode there was a progressive migration of active faulting towards the basin margins and as a result a widening with time of the area undergoing subsidence asymmetric subsidence of the central part of the basin was hinged at the western margin of the horda platform and accommodated to the nw on major faults within the tampen spur factors for the second rifting episode were calculated both by relating subsidence to extension and by measuring observed extension values calculated by both methods increase consistently towards the basin axis for both rifting and thermal subsidence phases but are greater for the latter phase subsidence patterns are similar for both rifting and thermal subsidence episodes so that there is vertical stacking of relatively thick sequences in the axis of the northern viking graben these factors preclude the application of models involving uniform and non uniform stretching and also preclude oblique extension depth dependent stretching is preferred

icesat waveform measurements of within footprint topographic relief and vegetation vertical structure 1 the ice cloud and land elevation satellite icesat mission determines land surface vertical structure within laser footprints due to topographic relief and vegetation using received waveforms recorded by the geoscience laser altimeter system glas in low relief areas with tree cover the waveforms and derived elevation products provide useful biophysical parameters including maximum canopy height crown depth the outer canopy ruggedness and a measure of canopy cover for areas where within footprint topographic relief is large compared to vegetation height interpretation of the waveforms is complex the contribution of canopy and ground to received waveforms is illustrated by comparing them with co located waveforms computed using an instrument model applied to high resolution digital elevation models dems the model includes representations of the transmit pulse s spatial and temporal distributions and the receiver field of view sensitivity and temporal smoothing this provides a means to validate glas waveforms elevation products and footprint geolocation

topographic mapping from interferometric synthetic aperture radar observations interferometric synthetic aperture radar observations provide a means for obtaining high resolution topographic terrain maps from data acquired simultaneously at two slightly displaced antennas calculation of the three dimensional coordinates of all the points in a radar image can be made from the combination of along track slant range and interferometer fringe measurements thus the result compensates for the layover exhibited by conventional radar maps and removes the false targets generated by multiple signal paths to a given object in the scene we have derived a topographic map of a portion of the san francisco bay area utilizing data that were recorded by a radar system mounted on a nasa cv990 aircraft and processed by a general purpose digital computer this map displays the height above sea level of a region approximately 11 km by 10 km in size sampled on an 11 m pixel grid uncertainties in the estimated height result from imprecise knowledge of the observational geometry radar bandwidth limitations and finite signal to noise ratios for our system each factor contributed approximately 3 4 m to a relative rms error of about 6 m additional global errors of the order of 10 m can result from inaccurate monitoring of aircraft attitude the statistical variation of the height measurements from the ocean portion of the map which we can presume to be quite flat is 2 10 m rms which is consistent with the theoretical estimate comparison of our results with u s geological survey contour maps indicates a high degree of correlation between the two sets of altitude data

estimation of forest structure ground and canopy layer characteristics from multibaseline polarimetric interferometric sar data this paper concerns forest parameter retrieval from polarimetric interferometric synthetic aperture radar polinsar data considering two layers one for the ground under the vegetation and one for the volumetric canopy a model is designed to combine a physical model based polarimetric decomposition with the random volume over ground rvog polinsar parameter inversion approach the combination of a polarimetric scattering media model with a polinsar rvog vertical structure model provides the possibility to separate the ground and the volume coherency matrices based on polarimetric signatures and interferometric coherence diversity the proposed polarimetric decomposition characterizes volumetric media by the degree of polarization orientation randomness and by the particle scattering anisotropy using the full model enhances the estimation of the vertical forest structure parameters by enabling us to estimate the ground to volume ratio the temporal decorrelation and the differential extinction for forest vegetation observed at l band this model accounts for the ground topography forest and canopy layer heights wave attenuation in the canopy tree morphology in the form of the angular distribution and the effective shapes of the branches and the contributions from the ground level consisting of surface scattering and double bounce ground trunk interactions as well as volumetric understory scattering the parameter estimation performance is evaluated on real airborne l band sar data of the traunstein test site acquired by the german aerospace center dlr s e sar sensor in 2003 in both single and multibaseline configurations the retrieved forest height is compared with the ground truth measurements revealing for the given test site an average root mean square error rmse of about 5 m in the repeat pass configuration this implies an improvement in rmse by over 2 m in comparison to the pure coherence based rvog polinsar parameter inversion

traps associated with paleovalleys and interfluves in an unconformity bounded sequence lower cretaceous glauconitic member southern alberta canada the glauconitic member in badger little bow retlaw and turin fields is an unconformity bounded sequence that formed on an ancient coastal plain in response to relative sea level fluctuations the member consists of valley fill and inter valley strata valley fill sandstone bodies are thick elongate pods that formed from inner estuarine bars when sedimentation was laterally confined between valley margins inter valley sandstone bodies are thin discontinuous sheets that accumulated during highstands when outer estuarine embayments covered interfluvial areas adjacent to associated valleys numerous oil pools are stratigraphically trapped within quartzose sandstones in valley fill and inter valley strata of the glauconitic member in the study area common updip seals for these reservoirs are 1 intra sequence facies changes from sandstone to shale and 2 low permeability lithic sandstones that fill the cross cutting paleovalleys of a younger sequence traps associated with many valley fill pools are enhanced by differential compaction anticlines several oil pools in the study area are hosted by discrete quartzose sandstone bodies that lie beneath a valley filled with low permeability lithic sandstone these quartzose sandstone bodies are interpreted to be remnants of older glauconitic deposits that escaped erosion when a younger valley incised into and followed the trend of one or more older glauconitic valleys

perspectives on the sequence stratigraphy of continental strata this report is the result of a working group on continental sequence stratigraphy that was set up at the 1991 nuna conference in banff canada to date sequence stratigraphic concepts have been applied mainly to the marine realm but unconformity bounded units have long been recognized in nonmarine strata successful application of sequence stratigraphic concepts to continental strata requires careful consideration of controls on base level and sediment supply as with shallow marine environments relative sea level can be considered as the stratigraphic as well as the geomorphic base level for coastal nonmarine settings farther inland stratigraphic base level which determines accommodation space is more complex and takes various forms such as the graded profile for fluvial strata groundwater tables for some eolian strata and lake level for some intermontane sediments sediment supply is also generally a more complex variable for nonmarine environments than in the marine realm because of the proximity to the source area the influence of climate and tectonism on sediment supply can clearly be seen in many continental sediments the fact that the major controls of climate tectonism and eustasy are somewhat interdependent and that a change in one parameter will most likely be reflected in others is also more readily apparent in continental strata although in its infancy sequence stratigraphic concepts have been applied to a wide variety of continental settings in attempts to explain variations in facies architecture of particular interest are studies that have linked fluvial architecture on coastal plains to variations in relative sea level as indicated by coeval marine strata and studies of lacustrine environments that show marked variation in facies between highstand and lowstand deposits the application of sequence stratigraphy to continental strata will likely result in the development of better correlation techniques and models that better predict the location and nature of fluvial and eolian reservoirs

transvaporite model of ore genesis and an exploration strategy for new giant ore deposits abstract in the current work we stand for the revival of the transvaporite ore genesis model which was introduced by hungarian academician e szadeczky kardoss more than half a century ago but has now fallen out of favor and superseded by the orthomagmatic model our arguments in support of the transvaporite model are based on the contemporary overpressure theory developed for mesozoic cenozoic petroleum basins we propose a new variant of the transvaporization model whereby the formation of giant ore deposits occurs in the areas where former petroleum rich basins are intersected by large igneous provinces lips at such sites structural magmatic activity leads to hydrocarbon deposits being destroyed and many new ore deposits being created beneath a new regional volcanic fluid seal built by rapidly accumulating up to 3 4 km in 1 ma lava flows in such conditions a zone of significant overpressure that is 1 4 1 8 times higher than hydrostatic pressure develops subsequently under the influence of compressive mechanism of mass transfer gas saturated brines of sedimentary rocks migrate toward intruding melts and then mix with them as a result unusual rocks transvaporites are formed and giant ore deposits created here we review six supergiant ore deposits of various types and ages with different associations of metals and host rocks including the norilsk district in russia cu ni co pt pd el teniente los bronces district in chile cu mo almaden deposit in spain hg ermakovskoe deposit in russia be pebble copper deposit in southern alaska cu mo au and olympic dam deposit in southern australia u cu au ree noting that all listed metals in each and every deposit do reach giant reserves in all these deposits transvaporization appears to play the key role in ore genesis given the 1 short duration of the main ore genesis stage a significant practical implication of the transvaporite model is that it should modify future strategies for ore deposits exploration instead of pursuing just any deposit exploration efforts should focus specifically on giant ore deposits concentrating search efforts at the sites where former petroleum basins have been intersected by lips basin analysis of enriched oil and gas provinces is already being conducted in detail by seismic transects involving two dimensional cross sections and areal surveys followed by three dimensional mapping of productive reservoirs the same strategy should be applied to ore bearing regions but at better precision and accuracy given the smaller velocity contrast in seismic wave propagation in ore rocks compared with oil and gas bearing sedimentary rocks important advances in the ore geology of lips such as geological mapping and gravity and magnetic surveys have already produced significant new data these studies can be divided into two types which first involve a general description of the lip and are then followed by an investigation of major intrusions likely to be directly linked to ore genesis a combination of these investigations into hydrocarbon basins and lips will lay the foundation for transvaporite exploration which will be the key criterion for the successful search for new giant ore deposits

crust and upper mantle structure of the north china craton and the ne tibetan plateau and its tectonic implications abstract understanding the mesozoic cenozoic tectonic evolution of the north china craton ncc and the ne tibetan plateau tp requires detailed knowledge of the lithospheric structure using dense regional networks and temporary deployments as well as updated reference models we obtain the crust and upper mantle structure to 120 km depth our tomographic results show several major features which have particular implications for the weihe shanxi rift system wsrs deformation of the ne tp and lithospheric evolution of the ncc beneath the wsrs the crust gradually thickens from south to north the lithospheric mantle gradually becomes slower and the mid lower crustal velocities are lower in the weihe rift where rifting of the wsrs initiated we suggest that along strike variations of the lithospheric structures of the wsrs have played an important role in its multistage evolution a low velocity zone lvz in the mid crust beneath the qilian orogen is characterized by relatively higher velocities compared to lvzs in other parts of the tp thus coherent lithospheric deformation may occur due to the high viscosity of the lvz during early plateau growth causing strong anisotropy to develop the western ncc including the ordos block and part of the alashan block shows a high velocity cratonic root extending to the base of our model in contrast the lithosphere of the eastern ncc appears to have been completely modified during the mesozoic through cenozoic and presents a thin lithosphere of relatively low velocities underlain by hot asthenosphere we observed significant upper mantle heterogeneities in the ncc which may reflect its diachronous lithospheric modification

waveform inversion of surface wave data test of a new tool for systematic investigation of upper mantle structures summary in most tomographic inversion of surface wave data the long period seismograms are first interpreted in terms of dispersion and or attenuation curves before performing an inversion in terms of laterally and depth varying properties an alternative to this approach is to perform a direct waveform inversion or as in cara lev que 1987 to use another set of secondary observables built up from the seismograms in this paper we systematically test with actual rayleigh wave records this latter technique by considering laterally homogeneous models we use for this purpose a set of recent long period digital records from the geoscope station dumont d urville antarctica for surficial events in the south indian ocean and the southeast pacific ocean and for intermediate depth events in the vanuatu and kermadec trenches in addition to the obvious advantages of being able to deal with situations where overtones are present in the seismogram it is found that the waveform inversion procedure allows us to reach a better depth resolution than in classical inversion of dispersion curves even when only the fundamental mode is present in the seismogram quite good resolution is obtained to depth as large as 300km for s velocity when using surficial events located at a few thousand kilometres from the station while classical surface wave studies do not allow us to resolve s velocity at depth larger than 150 km for these events when intermediate depth events are used at distances of about 5000 km the presence of overtones in the signal allows us to get resolution to depth as large as 600 km for s velocity poorer resolution is obtained in both situations for the attenuation factor s velocity appears furthermore to be more robust than attenuation at depth where good resolution is achieved due to the great sensitivity of surface wave amplitude to departure from the assumption of lateral homogeneity more sophisticated direct modelling would be required to get more confidence in the inverted attenuation models

velocity measurement bias of the ambient noise method due to source directivity a case study for the swedish national seismic network the bias of velocity measurements from ambient noise covariograms due to an anisotropic distribution of noise sources is studied assuming that the noise field consists of planar surface waves from

variability of channel belt dimensions and the consequences for alluvial architecture observations from the holocene rhine meuse delta the netherlands and lower mississippi valley u s a abstract over the past decades many studies have focused on the dimensions of channel belt sand bodies referred to as channel belts in fluvial deposits because of their relevance for hydrocarbon exploration and production some field studies have revealed a significant downstream decrease of channel belt width and width thickness ratio along the length of the channel belt to verify whether this is a common feature in fluviodeltaic settings eight holocene channel belts in the rhine meuse delta the netherlands were selected and one in the lower mississippi valley u s a we determined channel belt geometry width or width thickness ratio using geological geomorphological maps and detailed cross sections based on borings it was found that the width of channel belts encased in cohesive deposits decreases by a factor of 4 to 6 5 in a downstream direction along the length of the channel belts the width thickness ratio decreases by a factor of 2 5 to 5 on the other hand the width of a channel belt incised in a noncohesive substrate remains constant along its entire course these observations are related to longitudinal changes in bank erodibility and stream power it is suggested that bank erodibility is the dominating factor determining the geometric properties of channel belts and the variability therein at least in the rhine meuse delta the currently available alluvial architecture models most likely overestimate sand quantities and connectedness in alluvial successions because channel belt dimensions are held constant in all models we therefore propose that the factors bank erodibility and stream power which influence width and width thickness ratio of channel belts should be incorporated in future alluvial architecture models in order to make more realistic estimates of sand quantities in river deltas

a synoptic view of the distribution and connectivity of the mid crustal low velocity zone beneath tibet 1 based on 1 2 years of continuous observations of seismic ambient noise data obtained at more than 600 stations in and around tibet rayleigh wave phase velocity maps are constructed from 10 s to 60 s period a 3 d vsv model of the crust and uppermost mantle is derived from these maps the 3 d model exhibits significant apparently inter connected low shear velocity features across most of the tibetan middle crust at depths between 20 and 40 km these low velocity zones lvzs do not conform to surface faults and significantly are most prominent near the periphery of tibet the observations support the internal deformation model in which strain is dispersed in the deeper crust into broad ductile shear zones rather than being localized horizontally near the edges of rigid blocks the prominent lvzs are coincident with strong mid crustal radial anisotropy in western and central tibet and probably result at least partially from anisotropic minerals aligned by deformation which mitigates the need to invoke partial melt to explain the observations irrespective of their cause in partial melt or mineral alignment mid crustal lvzs reflect deformation and their amplification near the periphery of tibet provides new information about the mode of deformation across tibet

first demonstration of airborne sar tomography using multibaseline l band data in synthetic aperture radar sar interferometry the phase differences between two different sensor positions are used to estimate the terrain topography although it is possible in this way to find a three dimensional 3d surface representation the distribution of the different scatterers in the height direction at a fixed range and azimuth position remains unknown contrary to this tomographic techniques enable a real geometric resolution capability in the height direction and introduce new possibilities for many applications and inversion problems even misinterpretations in sar images caused by layover and foreshortening effects can be solved by the tomographic processing in this paper the successful experimental realization of polarimetric airborne sar tomography is demonstrated for the first time the authors present the concept of aperture synthesis for tomographic imaging for the case of a multibaseline imaging geometry and discuss the constraints arising from the limited number of flight tracks they propose a method for reduction of the height ambiguities associated to the irregular and undersampled spatial distribution of the imaging positions finally they address the experimental requirements for polarimetric airborne sar tomography and show experimental results using a multibaseline data set acquired in l band by dlr s experimental sar e sar of a test site near oberpfaffenhofen germany

eastward expansion of the tibetan plateau by crustal flow and strain partitioning across faults the tibetan plateau is expanding eastwards but the modes of deformation are poorly understood high resolution seismic images from the region identify localized zones of weak crustal rocks as well as deep faults implying that deformation occurs through a combination of crustal flow and movement of rigid blocks of crust