exploring solute transport and streamline connectivity using lidar based outcrop images and geostatistical representations of heterogeneity 1 using high resolution lidar scans of a braided stream deposit we investigate solute transport characteristics and streamline based connectivity that are lost when simulating the outcrop heterogeneity using geostatistical methods based on two point covariance functions attributes of the lidar scans were used to segment the outcrop into sand and gravel dominated lithofacies simulated fields were created using sequential indicator methods based on the two point covariance of the binary segmented lidar field sand and gravel lithofacies are then assigned reasonable hydraulic conductivity values two dimensional advective diffusive solute transport simulations in the segmented lidar field show strong solute focusing through gravel dominated strata resulting in a heavy tailed e g non fickian breakthrough the sequential indicator fields do not replicate the early and late time arrival characteristics streamline based analysis shows that the sequential indicator fields do not reproduce connectivity of the segmented lidar field even when the sequential indicator fields are highly conditioned streamlines migrate between sands and gravel beds nearly twice as often as streamlines in the segmented lidar field

the southern caspian a compressional depression floored by a trapped modified oceanic crust the south caspian intracontinental depression floored by oceanic basement is a relatively stable block with minor deformation surrounded by active fold thrust belts of arcuate form talesh alborz and kopeh dagh mountains which have undergone intense late cainozoic crustal shortening the basin is interpreted as a neogene quaternary compressional depression bounded by multi role mountain bordering reverse faults and apparently floored by a late paleozoic triassic or late mesozoic early tertiary modified oceanic crust trapped along an old geosuture it may be a relic of an old paleozoic triassic ocean or else a marginal sea developed behind a mesozoic paleogene ocean and analysis of geological and geophysical data enables a scheme to be suggested the general arcuate shape of the alborz and the talesh bordering mountain belts follows the pattern of the supposed rigid and thickened ocean crust of south caspian depression a tectono sedimentary study of the south caspian region coupled w

flexural plate subsidence sedimentation rates and structural development of the super deep south caspian basin abstract on a 270 km long seismic line across the west central and central parts of the south caspian basin an inverse flexural plate method is used to recover original uploaded plate parameters the original plate shows remarkable consistency of parameters determined from the 12 second deep seismic line with average rigidity d 1023 6nm bending moment m 1016n dip angle 0 14 and in line compressive stress of 1012 3n m 1 by sequentially adding the sedimentary units to the average bare basement it is shown that the geometry of the basin at jurassic time had a major downward warp and high sedimentary fill to the west leaving the eastern section open to possible erosion during early and middle cretaceous time the deep western part of the basin was then filled by sediments during late tertiary quaternary time and a new depocenter created across the central and western parts of the basin this newer depocenter was then filled during pliocene quaternary time the combined flexure of the basement plate and corresponding sediment fill behaviors with time are indicative of corresponding lithologic variations across the basin and with suspected organic rich sediments the integrated description of basement sediments and depocenter behavior points to the utility of the inverse procedure for improving our understanding of basinal evolution the value of rigidity is comparable to estimated oceanic crust values in line with the suspected tethys oceanic fragment of an island arc below the sediments the shift in depositional behavior with time from west to more northerly across the line of section is tied to the orogenic rise of the caucasus mountains to the north of the section and to the continued subduction of the talysh vandam plate fragment northward today the transpressional nature of the basin and the resolution of the in line compressive stress into components perpendicular to the great caucasus 70 and also perpendicular to the west caspian deep laid fault 25 30 are both in accord with the 25 30 km of present day sedimentary cover including the variations of thicknesses of seismic stratigraphic units along the section from azerbaijan in the west to nearly the turkmenian border in the east

identification of high permeability subsurface structures with multiple point geostatistics and normal score ensemble kalman filter abstract alluvial aquifers are often characterized by the presence of braided high permeable paleo riverbeds which constitute an interconnected preferential flow network whose localization is of fundamental importance to predict flow and transport dynamics classic geostatistical approaches based on two point correlation i e the variogram cannot describe such particular shapes in contrast multiple point geostatistics can describe almost any kind of shape using the empirical probability distribution derived from a training image however even with a correct training image the exact positions of the channels are uncertain state information like groundwater levels can constrain the channel positions using inverse modeling or data assimilation but the method should be able to handle non gaussianity of the parameter distribution here the normal score ensemble kalman filter ns enkf was chosen as the inverse conditioning algorithm to tackle this issue multiple point geostatistics and ns enkf have already been tested in synthetic examples but in this study they are used for the first time in a real world case study the test site is an alluvial unconfined aquifer in northeastern italy with an extension of approximately 3 km 2 a satellite training image showing the braid shapes of the nearby river and electrical resistivity tomography ert images were used as conditioning data to provide information on channel shape size and position measured groundwater levels were assimilated with the ns enkf to update the spatially distributed groundwater parameters hydraulic conductivity and storage coefficients results from the study show that the inversion based on multiple point geostatistics does not outperform the one with a multigaussian model and that the information from the ert images did not improve site characterization these results were further evaluated with a synthetic study that mimics the experimental site the synthetic results showed that only for a much larger number of conditioning piezometric heads multiple point geostatistics and ert could improve aquifer characterization this shows that state of the art stochastic methods need to be supported by abundant and high quality subsurface data

mapping ocean observations in a dynamical framework a 2004 06 ocean atlas abstract this paper exploits a new observational atlas for the near global ocean for the best observed 3 yr period from december 2003 through november 2006 the atlas consists of mapped observations and derived quantities together they form a full representation of the ocean state and its seasonal cycle the mapped observations are primarily altimeter data satellite sst and argo profiles gcm interpolation is used to synthesize these datasets and the resulting atlas is a fairly close fit to each one of them for observed quantities especially the atlas is a practical means to evaluate free running gcm simulations and to put field experiments into a broader context the atlas derived quantities include the middepth dynamic topography as well as ocean fluxes of heat and salt freshwater the atlas is publicly available online www ecco group org this paper provides insight into two oceanographic problems that are the subject of vigorous ongoing research first regarding ocean circulation estimates

a test of analog based tools for quantitative prediction of large scale fluvial architecture outcrop analogs are routinely used to constrain models of subsurface fluvial sedimentary architecture built through stochastic modeling or interwell sand body correlations correlability models are analog based quantitative templates for guiding the well to well correlation of sand bodies whereas indicator variograms used as input to reservoir models can be parameterized from data collected from analogs using existing empirical relationships this study tests the value and limitations of adopting analog informed correlability models and indicator variogram models and assesses the effect and significance of analog choice in subsurface workflows for characterizing fluvial reservoirs a 3 2 km 2 mi long architectural panel based on a virtual outcrop from the cretaceous blackhawk formation wasatch plateau utah has been used to test the methodologies vertical dummy wells have been constructed across the panel and the intervening fluvial architecture has been predicted using correlability models and sequential indicator simulations the correlability and indicator variogram models employed to predict the outcrop architecture have been compiled using information drawn from an architectural database these models relate to 1 analogs that partially match with the blackhawk formation in terms of depositional setting and 2 empirical relationships relating statistics on depositional element geometries and spatial relations to net to gross ratio based on data from multiple fluvial systems of a variety of forms the forecasting methods are assessed by quantifying the mismatch between predicted architecture and outcrop observations in terms of the correlability of channel complexes and static connectivity of channel deposits results highlight the effectiveness of correlability models as a check for the geologic realism of correlation panels and the value of analog informed indicator variograms as a valid alternative to variogram model parameterization through geostatistical analysis of well data this work has application in the definition of best practice use of analogs in subsurface workflows it provides insight into the typical degree of realism of analog based predictions of reservoir architecture as well as the effect of analog choice and draws attention to associated pitfalls

a meta study of relationships between fluvial channel body stacking pattern and aggradation rate implications for sequence stratigraphy a quantitative comparison of 20 literature case studies of fluvial sedimentary successions tests common assumptions made in published models of alluvial architecture concerning 1 inverse proportionality between channel deposit density and floodplain aggradation rates and 2 resulting characteristics of channel body geometries and connectedness our results do not support the relationships predicted by established stratigraphy models the data suggest that channel body density geometry and stacking pattern are not reliable diagnostic indicators of rates of accommodation creation hence these architectural characteristics alone do not permit the definition of accommodation based systems tracts and settings and this calls into question current sequence stratigraphic practice in application to fluvial successions

on the effects of small scale variability on acoustic propagation in fram strait the tomography forward problem acoustic tomography systems have been deployed in fram strait over the past decade to complement existing observing systems there the observed acoustic arrival patterns are unusual however consisting of a single broad arrival pulse with no discernible repeating patterns or individual ray arrivals the nature of these arrivals is caused by vigorous acoustic scattering from the small scale processes that dominate ocean variability in fram strait simple models for internal wave and mesoscale variability were constructed and tailored to match the variability observed by moored thermisters in fram strait the internal wave contribution to variability is weak acoustic propagation through a simulated ocean consisting of a climatological sound speed plus mesoscale and internal wave scintillations obtains arrival patterns that match the characteristics of those observed i e pulse width and travel time variation the scintillations cause a proliferation of acoustic ray paths however reminiscent of ray chaos this understanding of the acoustic forward problem is prerequisite to designing an inverse scheme for estimating temperature from the observed travel times

new empirical relationships among magnitude rupture length rupture width rupture area and surface displacement source parameters for historical earthquakes worldwide are compiled to develop a series of empirical relationships among moment magnitude m surface rupture length subsurface rupture length downdip rupture width rupture area and maximum and average displacement per event the resulting data base is a significant update of previous compilations and includes the additional source parameters of seismic moment moment magnitude subsurface rupture length downdip rupture width and average surface displacement each source parameter is classified as reliable or unreliable based on our evaluation of the accuracy of individual values only the reliable source parameters are used in the final analyses in comparing source parameters we note the following trends 1 generally the length of rupture at the surface is equal to 75 of the subsurface rupture length however the ratio of surface rupture length to subsurface rupture length increases with magnitude 2 the average surface displacement per event is about one half the maximum surface displacement per event and 3 the average subsurface displacement on the fault plane is less than the maximum surface displacement but more than the average surface displacement thus for most earthquakes in this data base slip on the fault plane at seismogenic depths is manifested by similar displacements at the surface log linear regressions between earthquake magnitude and surface rupture length subsurface rupture length and rupture area are especially well correlated showing standard deviations of 0 25 to 0 35 magnitude units most relationships are not statistically different at a 95 significance level as a function of the style of faulting thus we consider the regressions for all slip types to be appropriate for most applications regressions between magnitude and displacement magnitude and rupture width and between displacement and rupture length are less well correlated and have larger standard deviation than regressions between magnitude and length or area the large number of data points in most of these regressions and their statistical stability suggest that they are unlikely to change significantly in response to additional data separating the data according to extensional and compressional tectonic environments neither provides statistically different results nor improves the statistical significance of the regressions regressions for cases in which earthquake magnitude is either the independent or the dependent parameter can be used to estimate maximum earthquake magnitudes both for surface faults and for subsurface seismic sources such as blind faults and to estimate the expected surface displacement along a fault for a given size earthquake

wigwam reverberation revisited operation wigwam was a test of a 30 kt nuclear depth charge conducted in deep water 500 miles southwest of san diego on 14 may 1955 its primary purpose was to determine the effectiveness of that device as an antisubmarine weapon the acoustic pulse from the test initially an intense shockwave radiated throughout the north and south pacific oceans acoustic reflections from topographic features were recorded for several hours after the explosion by sound fixing and ranging sofar hydrophones at point sur california and kaneohe hawaii sheehy and halley 1957 identified peaks of the recorded coda with reflections from specific topographic features at great distances e g the hawaiian islands french polynesia or fiji with modern data for seafloor topography and ocean sound speed these coda were computed with surprising accuracy using simple geodesic rays reflected from islands and seamounts the intensity variations of the coda are mostly determined by simple ray geometry together with modest attenuation coda peaks are often obtained from rays arriving simultaneously from multiple but disparate topographic features online material figures of computed and measured coda and associated geodesic paths

high resolution aquifer analog of fluvial aeolian sediments of the guarani aquifer system the guarani aquifer system gas represents one of the biggest aquifers in the world and is the most relevant groundwater resource in south america for the first time by combining field and laboratory measurements a high resolution aquifer analog model of fluvial aeolian sediments of the gas in sao paulo state brazil is constructed three parallel sections of frontal outcrops 28 m 5 8 m and two parallel sections of lateral outcrops 7 m 5 8 m are recorded during open pit mining of sandy sediments and describe in detail the three dimensional distribution of the local lithofacies and hydrofacies variations of hydraulic conductivity k and porosity n are resolved on the centimeter scale and the most permeable units of the fluvial aeolian facies association are identified the constructed aquifer analog model shows moderate hydraulic heterogeneity and a mean k value of 1 36 10 4 m s which is greater than the reported range of k values for the entire gas in sao paulo state the results suggest that the examined sedimentary unit constitutes a relevant portion of the gas in sao paulo state in the context of groundwater extraction and pollution moreover the constructed aquifer analog is considered an ideal basis for future numerical model experiments aiming at in depth understanding of the groundwater flow and contaminant transport patterns at this gas portion or at comparable fluvial aeolian facies associations

capturing channelized reservoir connectivity uncertainty with amalgamation curves abstract during reservoir characterization all the geological uncertainties affecting the quantity and distribution of hydrocarbons should be captured to assess the risks affecting final recovery in a typical modeling workflow the geological uncertainties are accounted for through the construction of a sufficiently large set of 3 d static models out of this set a few representative models are selected and dynamically simulated so as to correlate the geological characteristics of the reservoir with its dynamic performance and to propagate the uncertainty onto the final recovery factors yet maintaining the computational run time acceptable in channelized depositional environments which are strongly heterogeneous the selection approach must also account for channel connectivity which plays a key role in the possibility of efficiently draining the reservoir for a reasonable number of wells this study can be seen as a step forward in the assessment of the risks associated to the development of channelized reservoirs under the assumption that a way to express the concept of channel connectivity is channel amalgamation channel amalgamation is here defined through amalgamation curves which are numerically described using a set of indexes whose combination provide spatial information of channel intersections these indexes were calculated for a full set of 3 d geological models and used to steer the selection of a representative model sub set for subsequent fluid flow simulations the validity of the index based selection was verified on different sets of synthetic reservoir models through the evaluation of the representativeness of the model sub set in reproducing the uncertainty of the original dataset eventually the existence of a strong correlation between channel amalgamation and production performance was proved from a practical perspective the possibility to include channel amalgamation in the assessment of the geological models can considerably improve the representativeness of the selected models for uncertainty propagation thus reducing significantly the number of geological models to be considered

architecture and stratigraphy of alluvial deposits morrison formation upper jurassic utah this article presents a unique cross section of a 13 5 km 8 3 mi long by 150 m 492 ft thick stratigraphic interval containing braided stream and associated flood plain deposits the cross section is oriented approximately parallel to depositional strike this cross section is a resource for geoscientists and engineers interested in the measurements of stratigraphic architectural elements such as dimensions and continuity of facies tracts and facies associations stratigraphic and geographic changes in sandstone mudstone proportions net to gross and frequency and cause of vertical fluid communication between superposed reservoirs in addition to presenting this rich data resource observed and documented stratigraphic relationships add to our conceptual understanding of certain attributes of the stratigraphic process response system for example we show that like meandering rivers aggradational braided river systems also build levees and alluvial ridges providing the supra elevation above the adjacent floodplain to create extensive crevasse splay and channel complexes we show that superposed channel sandstone reservoirs may be brought into physical contact not only by the erosion of an upper sand into a lower sand but also by the vertical aggradation of the lower sandstone producing a pyramid on which a younger sandstone is deposited four stratigraphic cycles of increasing and decreasing accommodation sediment supply a s regimes are identified these cycles are recognized from systematic vertical changes in stratigraphic and sedimentologic attributes at the largest scale there is a progressive downhill shift in facies tracts recording a basinward stepping of the four stratigraphic cycles at the intermediate scale there is a systematic change in channel types from laterally amalgamated braided channels to vertically building braided channels to steer head distributary channels encased within lacustrine dominated fines at the smallest scale systematic and repeated vertical successions of facies occur within the three types of channel belts these systematic changes are related to progressive changes in the a s regime that occur during superimposed stratigraphic base level cycles of three different scales

implications of earthquake focal mechanism data for the active tectonics of the south caspian basin and surrounding regions summary the south caspian basin is a relatively aseismic block within the alpine himalayan belt but is surrounded by zones of high seismicity we used the focal mechanisms of 16 earthquakes whose source parameters we determined from inversion of body waves and the mechanisms of 15 other earthquakes to determine the style of faulting in the seismic belts surrounding the south caspian basin earthquakes beneath the talesh mountains of north west iran and immediately off shore in the south west caspian sea have shallow thrust mechanisms showing that the continental crust of north west iran is overthrusting the oceanic like crust of the south caspian basin earthquakes south of the caspian sea in northern iran show a mixture of focal mechanisms both high angle reverse faulting and left lateral strike slip faulting mechanisms are observed in the high alborz mountains farther south on the edge of the central iran plateau oblique left lateral reverse mechanisms are observed it appears that the ne direction of shortening between central iran and the south caspian basin is partitioned into pure left lateral strike slip and thrusting in the wnw trending high alborz but is accommodated by oblique faulting in lower elevations earthquakes in the kopet dag mountains east of the caspian sea also show a mixture of high angle reverse and strike slip faulting mechanisms and may be another example of the partitioning of oblique slip into strike slip and thrust motion normal faulting mechanisms at centroid depths of 35 50 km dominate in the belt of seismicity that extends across the central caspian sea the significance of the normal faulting earthquakes is enigmatic it is improbable that these events represent the motion between the southern caspian basin and eurasia for they imply a sense of motion that is incompatible with the observed topography and folding in the sediments two shallow earthquakes at about 12 km depth in this belt one a small event and the other a large second subevent of a multiple earthquake have thrusting mechanisms suggesting that shortening occurs as the continental crust of the northern caspian sea is thrust over the oceanic like crust of the southern caspian basin shortening is also suggested by the orientations of folds in the sedimentary cover south of the central caspian sea seismic belt we suggest that this shortening does indeed represent a nne motion of the caspian sea relative to eurasia but that the motion is slow and has not produced many earthquakes the deeper normal faulting events may be related to bending or down dip extension of the incipient subducted slab if the motion of the caspian sea relative to eurasia is indeed slow then the motion in the alborz between central iran and the south caspian basin will be almost the same as that between iran and eurasia as has previously been assumed the combined effect of the overthrusting of the south caspian basin by the talesh alborz mountains in the south and by the continental crust of the northern caspian sea in the north will lead to the eventual destruction of the south caspian basin and the possible formation of an intermediate depth dipping seismic zone within the continental interior similar to that presently observed in the hindu kush

long range propagation of sound through oceanic mesoscale structures assumptions related to the feasibility of ocean acoustic tomography are investigated utilizing range dependent sound speed profiles the models include a warm midocean eddy and a cold core gulf stream ring superposed on a latitudinal geographic variation covering 1000 km the results show that changes in the acoustic travel times produced by mesoscale features can be nonlinear that the ray paths are substantially displaced by a mesoscale eddy and that information from a single source and receiver can be used to infer the distance to a mesoscale disturbance

turning point filters analysis of sound propagation on a gyre scale acoustic transmissions from pioneer seamount off california to a vertical array near hawaii are analyzed using a technique which we call a turning point filter the observables travel time and axial inclination are interpreted in terms of the ocean sound speed field the method permits a uniform treatment of the arrival pattern from the early ray like arrivals to the late mode like arrivals including peak arrivals which cannot be identified as either rays or modes an adiabatic range dependence is assumed and wentzel kramers brillouin jeffreys formalism is applied

three dimensional parabolic equation modeling of mesoscale eddy deflection the impact of mesoscale oceanography including ocean fronts and eddies on global scale low frequency acoustics is examined using a fully three dimensional parabolic equation model the narrowband acoustic signal for frequencies from 2 to 16 hz is simulated from a seismic event on the kerguellen plateau in the south indian ocean to an array of receivers south of ascension island in the south atlantic a distance of 9100 km the path was chosen for its relevance to seismic detections from the ha10 ascension island station of the international monitoring system for its lack of bathymetric interaction and for the dynamic oceanography encountered as the sound passes the cape of good hope the acoustic field was propagated through two years 1992 and 1993 of the eddy permitting ocean state estimation ecco2 estimating the circulation and climate of the ocean phase ii system the range of deflection of the back azimuth was 1 8 with a root mean square of 0 34 the refraction due to mesoscale oceanography could therefore have significant impacts upon localization of distant low frequency sources such as seismic or nuclear test events

active faulting and natural hazards in armenia eastern turkey and northwestern iran active fault zones of armenia se turkey and nw iran present a diverse set of interrelated natural hazards three regional case studies in this cross border zone are examined to show how earthquakes interact with other hazards to increase the risk of natural disaster in northern armenia a combination of several natural and man made phenomena earthquakes landslides and unstable dams with toxic wastes along the pambak sevan sunik fault pssf zone lowers from 0 4 to 0 2 0 3g the maximum permissible level mpl of seismic hazard that may induce disastrous destruction and loss of life in the adjacent vanadzor depression in the ararat depression a large active fault bounded pull apart basin at the junction of borders of armenia turkey iran and azerbaijan an earthquake in 1840 was accompanied by an eruption of ararat volcano lahars landslides floods soil subsidence and liquefaction the case study demonstrates that natural hazards that are secondary with respect to earthquakes may considerably increase the damage and the casualties and increase the risk associated with the seismic impact the north tabriz gailatu fault system poses a high seismic hazard to the border areas of nw iran eastern turkey nakhichevan azerbaijan and southern armenia right lateral strike slip motions along the north tabriz fault have given rise to strong earthquakes which threaten the city of tabriz with its population of 1 2 million the examples illustrate how the concentration of natural hazards in active fault zones increases the risk associated with strong earthquakes in armenia eastern turkey and nw iran this generally occurs across the junctions of international borders hence the transboundary character of active faults requires transboundary cooperation in the study and mitigation of the natural risk

spatial variability in river sediments and its link with river channel geometry 1 this study explores the link between spatial variability within fluvial sedimentary strata and river channel geometry this link is then used to determine the macrodispersion coefficients for solute transport in groundwater flow in river deposits in doing that we combine concepts from sedimentology geostatistics and the stochastic lagrangian theory of subsurface transport it is proposed to analyze the spatial variability of river sediments in terms of transition probabilities the transition probabilities can be determined from the averages and variances of the lengths of stratasets and their volumetric fractions using concepts developed by carle and fogg 1996 and ritzi 2000 strataset length scales are shown to correlate well with the geometry of the river channel and its bed forms and can be determined indirectly from aerial photogrammetry and more directly through surface ground penetrating radar surveys stratal dimensions can also be related using lagrangian transport analysis to macrodispersivity of subsurface transport this allows relationships between the geometry of river channels and subsurface transport parameters of associated fluvial deposits for demonstration the longitudinal macrodispersivity in a compound bar deposit in the gravelly braided sagavanirktok river was investigated

seismic sedimentologic study of facies and reservoir in middle triassic karamay formation of the mahu sag junggar basin china abstract the top sandstone s1 of the middle triassic karamay formation t2k is one of the major pay zones in the mahu field junggar basin northwestern china both spatial distribution and internal architecture of the reservoirs are important for resource evaluation and petroleum production in the field seismic sedimentology an integrated study of seismic geomorphology and seismic lithology was applied to well and three dimensional 3 d seismic data to analyze distribution of sedimentary facies and reservoirs lithologies in the study area consist of conglomerate sandstone and mudstone acoustic impedance ai of mudstone 6 9 106 kg s m2 is lower than the other two lithologies which have similar ai values 9 14 106 kg s m2 therefore seismic amplitude can distinguish mudstone from conglomerate and sandstone but fails to differentiate conglomerate from sandstone seismic geomorphology was employed to qualitatively predict distribution of sandstone and conglomerate respectively using frequency decomposition seismic attribute extraction and red green blue rgb color blending techniques in the seismic lithologic study principal component analysis pca was utilized to transfer multiple seismic attributes into principal components selected principal components were then fit with cumulative reservoir thickness interpreted from porosity log data resulting in quantitative estimation of interwell thin 10 m or thinner reservoir distribution meandering fluvial facies were recognized for the first time in the previously interpreted fan delta facies zone meandering channels formed when the lake level rose in relatively humid climate during a time with few tectonic activities the previously formed fan delta was substituted by a later formed meandering channel which flowed into the southwestern lake from the north sediment distribution was controlled by accumulation space or paleogeomorphology restored by cast method sediment is thick in paleolow terrains and thin in paleohigh areas locality of reservoir rock is basically coincident with sandstone distribution thick reservoir rocks with high porosity greater than 10 are located mainly in areas with moderately thick sandstones formed in point bar subfacies of fluvial systems and in lower fan subfacies of the fan delta system higher petroleum production in individual wells drilled in the fluvial system indicates superior physical properties there as a result locating point bar subfacies is key to improving hydrocarbon exploration and development

barotropic and baroclinic tides in the central north pacific ocean determined from long range reciprocal acoustic transmissions abstract travel times of reciprocal 1000 km range acoustic transmissions determined from the 1987 reciprocal tomography experiment are used to study barotropic tidal currents and a large scale coherent baroclinic tide in the central north pacific ocean the difference in reciprocal travel times determines the tidal currents while the sum of reciprocal travel times determines the baroclinic tide displacement of isotachs or equivalently isotherms the barotropic tidal current accounts for 90 of the observed differential travel time variance the measured harmonic constants of the eight major tidal constituents of the barotropic tide and the constants determined from current meter measurements agree well with the empirical numerical tidal models of schwiderski and cartwright et al the amplitudes and phases of the first mode baroclinic tide determined from sum travel times agree with those determined from moored thermistors and current meters the baroclinic tidal signals are consistent with a large

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

a comparison of measured and predicted broadband acoustic arrival patterns in travel time depth coordinates at 1000 km range broadband acoustic signals were transmitted from a moored 250 hz source to a 3 km long vertical line array of hydrophones 1000 km distant in the eastern north pacific ocean during july 1989 the sound speed field along the great circle path connecting the source and receiver was measured directly by nearly 300 expendable bathythermograph xbt conductivity temperature depth ctd and air launched expendable bathythermograph axbt casts while the transmissions were in progress this experiment is unique in combining a vertical receiving array that extends over much of the water column extensive concurrent environmental measurements and broadband signals designed to measure acoustic travel times with 1 ms precision the time mean travel times of the early raylike arrivals which are evident as wave fronts sweeping across the receiving array and the time mean of the times at which the acoustic reception ends the final cutoffs for hydrophones near the sound channel axis are consistent with ray predictions based on the direct measurements of temperature and salinity within measurement uncertainty the comparisons show that subinertial oceanic variability with horizontal wavelengths shorter than 50 km which is not resolved by the direct measurements significantly 25 ms peak to peak affects the time mean ray travel times the final cutoffs occur significantly later than predicted using ray theory for hydrophones more than 100 200 m off the sound channel axis nongeometric effects such as diffraction at caustics partially account for this observation

active transtension inside central alborz a new insight into northern iran southern caspian geodynamics the tectonic activity in the alborz mountain range northern iran is due both to the northward convergence of central iran toward eurasia and to the northwestward motion of the south caspian basin with respect to eurasia inducing a left lateral wrenching along this range these two mechanisms give rise to a nne ssw transpressional regime which is believed to have affected the entire range for the last 5 6 2 m y in this paper we show that the internal domain of central alborz is not affected by a transpressional regime but by an active transtension with a wnw ese extensional axis we show that this transten sion is young middle pleistocene it postdates an earlier n s compression and may have been initiated when the south caspian basin started moving consequently our results suggest that the south caspian basin motion may have taken place more recently than previously proposed

analysis of fluvial architecture in the blackhawk formation wasatch plateau utah u s a using large 3d photorealistic models abstract there are numerous allocyclic and autocyclic factors which influence fluvial sandbody geometry unraveling the relative importance of such factors is challenging because fluvial systems can migrate and avulse across significant distances on the floodplain so that collecting datasets that cover a large enough area with sufficient detail is difficult this problem has been addressed by acquiring an oblique helicopter mounted lidar survey over 16 km of exposed sections from cretaceous coastal plain deposits cropping out in the wasatch plateau of east central utah the exposures of the blackhawk formation occur in steep cliffs which are continuous for several tens of kilometers and have been previously inaccessible for study the recorded lidar data were used to build detailed photorealistic models virtual outcrops from which quantitative dimensional data on fluvial architectural elements mostly sandstone channel bodies were collected those channelized bodies show significant variation in width and thickness 26 of the sandbodies were identified as being multistory channel bodies with a thickness of 9 1 m 4 67 m 1 and a width of 142 6 m 180 7 m which are significantly larger than the measured single story sandbodies 5 9 m and 96 9 m respectively 50 of all sandbodies have aspect ratios smaller 13 1 and the highest values reach 78 1 the spatial constraint of the 397 fluvial sandbodies enabled the recognition of a series of vertical trends within the dataset these trends include a subtle upward increase in width and thickness of both the mean and maximum values this is coupled with a general upward decrease in the number of sandbodies and results in a broadly constant channel to overbank ratio a clear correlation between wider channels with increased distance to the shoreline could also be documented these observations can be explained by considering the entire blackhawk formation as the deposits of a large distributive fluvial system in this model the key control on channel architecture is the distance to the shoreline contrasting with previous interpretations of the blackhawk depositional system in which the rate of accommodation creation in the coastal plain was thought to be the key control on channel geometry and stacking patterns

mode coherence at megameter ranges in the north pacific ocean this article analyzes the coherence of low mode signals at ranges of 3515 and 5171 km using data from the acoustic thermometry of ocean climate atoc and alternate source test ast experiments vertical line arrays at hawaii and kiritimati received m sequences transmitted from two sources the 75 hz bottom mounted atoc source on pioneer seamount and the near axial dual frequency 28 84 hz ast source deployed nearby this study demonstrates that the characteristics of the mode signals at 5171 km range are quite similar to those at 3515 km range at 75 hz the mode time spreads are on the order of 1 5 s implying a coherence bandwidth of 0 67 hz the time spread of the 28 hz signals is somewhat lower but these signals show significantly less frequency selective fading than the 75 hz signals suggesting that at the lower frequency the multipaths are temporally resolvable coherence times for mode 1 at 75 hz are on the order of 8 min for the 3515 km range and 6 min for 5171 km range at 28 hz mode 1 is much more stable with a magnitude squared coherence of greater than 0 6 for the 20 min transmission period

sandstone body and shale body dimensions in a braided fluvial system salt wash sandstone member morrison formation garfield county utah excellent three dimensional exposures of the upper jurassic salt wash sandstone member of the morrison formation in the henry mountains area of southern utah allow measurement of the thickness and width of fluvial sandstone and shale bodies from extensive photomosaics the salt wash sandstone member is composed of fluvial channel fill abandoned channel fill and overbank flood plain strata that were deposited on a broad alluvial plain of low sinuosity sandy braided streams flowing northeast a hierarchy of sandstone and shale bodies in the salt wash sandstone member includes in ascending order trough cross bedding fining upward units mudstone intraclast conglomerates single story sandstone bodies basal conglomerate abandoned channel fill multistory sandstone bodies and overbank flood plain heterolithic strata trough cross beds have an average width thickness ratio w t of 8 5 1 in the lower interval of the salt wash sandstone member and 10 4 1 in the upper interval fining upward units are 0 5 3 0 m thick and 3 11 m wide single story sandstone bodies in the upper interval are wider and thicker than their counterparts in the lower interval based on average w t linear regression analysis and cumulative relative frequency graphs multistory sandstone bodies are composed of two to eight stories range up to 30 m thick and over 1500 m wide w t 50 1 and are also larger in the upper interval heterolithic units between sandstone bodies include abandoned channel fill w t 33 1 and overbank flood plain deposits w t 70 1 understanding w t ratios from the component parts of an ancient sandy braided stream deposit can be applied in several ways to similar strata in other basins for example to 1 determine the width of a unit when only the thickness is known 2 create correlation guidelines and maximum correlation lengths 3 aid in interpreting the controls on fluvial architecture and 4 place additional constraints on input variables to stratigraphic and fluid flow modeling the usefulness of these types of data demonstrates the need to develop more data sets from other depositional environments

on equations for the speed of sound in seawater long range acoustic transmissions made in conjunction with extensive environmental measurements and accurate mooring position determinations have been used to test the accuracy of equations used to calculate sound speed from pressure temperature and salinity the sound speed field computed using the del grosso equation v a del grosso j acoust soc am 56 1084 1091 1974 give predictions of acoustic arrival patterns which agree significantly better with the long range measurements than those computed using the chen and millero equation c chen and f j millero j acoust soc am 62 1129 1135 1977 the predicted ray travel times and travel time error have been calculated using objectively mapped sound speed fields computed from ctd and xbt data using the measured and predicted ray travel times a negligible correction to del grosso s equation of 0 05 0 05 m s at 4000 m depth is calculated small errors of about 50 m in the gps determination of mooring positions lends a depth independent error of 0 1 m s to the sound speed equation correction work supported by nsf and onr

a theoretical and simulation study of acoustic normal mode coupling effects due to the barents sea polar front with applications to acoustic tomography and matched field processing normal mode coupling due to a shallow water coastal front is considered using oceanographic data from the 1992 barents sea polar front bspf experiment as input to normal mode and parabolic equation pe acoustic propagation models criteria for the sensitivity of mode coupling to coastal front widths are derived and applied to the bspf as a representative example the effects of coastal fronts on tomographic schemes are considered particularly in terms of travel time based tomography the effects of frontal mode coupling on matched field processing schemes are also considered using both the maximum likelihood and variable coefficient likelihood methods which show differing sensitivities to mismatch finally directions for future research are discussed

seismic versus aseismic deformation in iran inferred from earthquakes and geodetic data summary a combined analysis of the geodetic strain rate field and the strain rate field deduced from the seismicity allows us to define the style of deformation and to distinguish seismic from aseismic deformation we perform this analysis in iran where the present day tectonics results from the north south convergence between the plates of arabia to the south and eurasia to the north the data consist of velocities measured with a gps network of 28 benchmarks and of instrumental and historical earthquake catalogues the axes of the seismic strain rate tensor have similar orientations to those deduced from the gps velocity field this indicates that the seismicity can be used to improve gps information on the style and the orientation of the deformation comparison of seismic and geodetic strain rates indicates that highly strained zones experience mainly aseismic deformation in southern iran and seismic deformation in northern iran a large contrast is observed between the zagros less than 5 per cent seismic deformation and the alborz kopet dag regions more than 30 100 per cent seismic deformation the distribution of the seismic geodetic ratio correlates with the distribution of large earthquakes intensive low magnitude seismicity is observed in the zagros whereas the largest earthquakes occur in northern iran the contrast of seismic deformation between the zagros and peri caspian mountains is confirmed considering 300 or 1000 yr of seismicity rather than 100 or 200 yr

a decade of acoustic thermometry in the north pacific ocean 1 over the decade 1996 2006 acoustic sources located off central california 1996 1999 and north of kauai 1997 1999 2002 2006 transmitted to receivers distributed throughout the northeast and north central pacific the acoustic travel times are inherently spatially integrating which suppresses mesoscale variability and provides a precise measure of ray averaged temperature daily average travel times at 4 day intervals provide excellent temporal resolution of the large scale thermal field the interannual seasonal and shorter period variability is large with substantial changes sometimes occurring in only a few weeks linear trends estimated over the decade are small compared to the interannual variability and inconsistent from path to path with some acoustic paths warming slightly and others cooling slightly the measured travel times are compared with travel times derived from four independent estimates of the north pacific 1 climatology as represented by the world ocean atlas 2005 woa05 2 objective analysis of the upper ocean temperature field derived from satellite altimetry and in situ profiles 3 an analysis provided by the estimating the circulation and climate of the ocean project as implemented at the jet propulsion laboratory jpl ecco and 4 simulation results from a high resolution configuration of the parallel ocean program pop model the acoustic data show that woa05 is a better estimate of the time mean hydrography than either the jpl ecco or the pop estimates both of which proved incapable of reproducing the observed acoustic arrival patterns the comparisons of time series provide a stringent test of the large scale temperature variability in the models the differences are sometimes substantial indicating that acoustic thermometry data can provide significant additional constraints for numerical ocean models

integrating non colocated well and geophysical data to capture subsurface heterogeneity at an aquifer recharge and recovery site abstract geophysical data have proven to be very useful for lithological characterization however quantitatively integrating the information gained from acquiring geophysical data generally requires colocated lithological and geophysical data for constructing a rock physics relationship in this contribution the issue of integrating noncolocated geophysical and lithological data is addressed and the results are applied to simulate groundwater flow in a heterogeneous aquifer in the prairie waters project north campus aquifer recharge site colorado two methods of constructing a rock physics transform between electrical resistivity tomography ert data and lithology measurements are assessed in the first approach a maximum likelihood estimation mle is used to fit a bimodal lognormal distribution to horizontal crosssections of the ert resistivity histogram in the second approach a spatial bootstrap is applied to approximate the rock physics relationship the rock physics transforms provide soft data for multiple point statistics mps simulations subsurface models are used to run groundwater flow and tracer test simulations each model s uncalibrated predicted breakthrough time is evaluated based on its agreement with measured subsurface travel time values from infiltration basins to selected groundwater recovery wells we find that incorporating geophysical information into uncalibrated flow models reduces the difference with observed values as compared to flow models without geophysical information incorporated the integration of geophysical data also narrows the variance of predicted tracer breakthrough times substantially accuracy is highest and variance is lowest in breakthrough predictions generated by the mle based rock physics transform calibrating the ensemble of geophysically constrained models would help produce a suite of realistic flow models for predictive purposes at the site we find that the success of breakthrough predictions is highly sensitive to the definition of the rock physics transform it is therefore important to model this transfer function accurately

horizontal refraction of acoustic signals retrieved from north pacific acoustic laboratory billboard array data in 1998 1999 a comprehensive low frequency long range sound propagation experiment was carried out by the north pacific acoustic laboratory npal in this paper the data recorded during the experiment by a billboard acoustic array were used to compute the horizontal refraction of the arriving acoustic signals using both ray and mode based approaches the results obtained by these two approaches are consistent the acoustic signals exhibited weak if any regular horizontal refraction throughut most of the experiment however it increased up to 0 4 deg the sound rays were bent towards the south at the beginning and the end of the experiment these increases occurred during midspring to midsummer time and seemed to reflect seasonal trends in the horizontal gradients of the sound speed the measured standard deviation of the horizontal refraction angles was about 0 37 deg which is close to an estimate of this standard deviation calculated using 3d modal theory of low frequency sound propagation throu

late cenozoic deformation in the south caspian region effects of a rigid basement block within a collision zone abstract active deformation in the south caspian region demonstrates the enormous variation in kinematics and structural style generated where a rigid basement block lies within a collision zone rigid basement to the south caspian basin moves with a westward component relative both to stable eurasia and iran and is beginning to subduct at its northern and western margins this motion is oblique to the approximately north south arabia eurasia convergence and causes oblique shortening to the south and northeast of the south caspian basin thrusting in the alborz and kopet dagh is accompanied by range parallel strike slip faults which are respectively left and right lateral there are also arcuate fold and thrust belts in the region for two principal reasons firstly weaker regions deform and wrap around the rigid block this occurs at the curved transition zone between the alborz and talysh ranges where thrust traces are concave towards the foreland secondly a curved fold and thrust belt can link a deformation zone created by movement of the basement block to one created by the regional convergence west to east thrusts in the eastern talysh represent underthrusting of the south caspian basement but pass via an arcuate fan of fold trains into ssw directed thrusts in the eastern greater caucasus which accommodates part of the arabia eurasia convergence each part of the south caspian region contains one or more detachment levels which vary dependent on the pre pliocene geology buckle folds in the south caspian basin are detached from older rocks on thick mid tertiary mudrocks whereas thrust sheets in the eastern greater caucasus detach on mesozoic horizons in the future the south caspian basement may be largely eliminated by subduction leading to a situation similar to archaean greenstone belts of interthrust mafic and sedimentary slices surrounded by the roots of mountain ranges constructed from continental crust

one million years from the upper arang formation west natuna basin implications for reservoir distribution and facies variation in fluvial deltaic deposits abstract the middle miocene upper arang formation west natuna basin offshore indonesia is an important petroleum system contributing dry gas to two gas contracts supplying singapore and malaysia over the next 20 years the formation was deposited in a predominantly perhumid environment with reservoirs comprising fluvial deltaic deposits with the gas sourced from numerous inter bedded coals periodic marine flooding events provide intra formational seals a series of horizon slices over a 1 million year geological time interval at a depth of approximately 4 800 ft have been generated from two large 3d surveys including coverage over the belanak field this geological period equates to a 300 ft well section but more significantly to only a 120 msec two way time seismic interval the slices have produced excellent images of environments of deposition and clearly illustrate how major changes in reservoir distribution and facies occur over this interval the seismic data illustrates the lateral and vertical complexity of these reservoirs which is not resolved by limited well penetrations the images have been used not only in the reservoir model for the belanak field but also as analogues for adjacent fields for both the upper arang formation and deeper reservoirs within the oligocene the 3d data is facilitating optimal development of these highly complex reservoirs

a re assessment of focal depth distributions in southern iran the tien shan and northern india do earthquakes really occur in the continental mantle summary we investigate the depth distribution of earthquakes within the continental lithosphere of southern iran the tien shan and northern india by using synthetic seismograms to analyse p and sh body waveforms in the zagros mountains of southern iran earthquakes are apparently restricted to the upper crust depths of 20 km whereas in the tien shan and northern india they occur throughout the thickness of the continental crust to depths of 40 45 km we find no convincing evidence for earthquakes in the continental mantle of these regions in spite of previous suggestions to the contrary and question whether seismicity in the continental mantle is important in any part of the world in some regions such as iran the aegean tibet and california seismicity is virtually restricted to the upper continental crust whereas in others including parts of east africa the tien shan and northern india the lower crust is also seismically active although usually less so than the upper crust such variations cannot reliably be demonstrated from published catalogue or bulletin locations even from ones in which depth resolution is generally improved in contrast to the oceanic mantle lithosphere in which earthquakes certainly occur the continental mantle lithosphere is we suggest virtually aseismic and may not be significantly stronger than the lower continental crust these variations in continental seismogenic thickness are broadly correlated with variations in effective elastic thickness suggesting that the strength of the continental lithosphere resides in the crust and require some modification to prevalent views of lithosphere rheology

models for guiding and ranking well to well correlations of channel bodies in fluvial reservoirs a probabilistic method has been devised to assess the geologic realism of subsurface well to well correlations that entail the lateral tracing of geologic bodies across well arrays with constant spacing models of geo body correlability based on the ratio between correlatable and penetrated geo bodies are obtained from total probabilities of penetration and correlation which are themselves dependent on the distribution of lateral extent of the geo body type employing outcrop analog data to constrain the width distribution of the geo bodies it is possible to generate a model that describes realistic well to well correlation patterns for given types of depositional systems this type of correlability model can be applied for checking the quality of correlation based subsurface interpretations by assessing their geologic realism as compared with one or more suitable outcrop analogs the approach is illustrated by generating total probability curves that refer to fluvial channel complexes and that are categorized on the basis of outcrop analog classifications e g braided system system with 20 net to gross employing information from a large fluvial geo body database fluvial architecture knowledge transfer system fakts which stores information relating to fluvial architecture from these total probability functions values can be drawn to adapt the correlability models to any well array spacing the method has been specifically applied to rank three published alternative interpretations of a stratigraphic interval of the travis peak formation texas previously interpreted as a braided fluvial depositional system in terms of realism of correlation patterns as compared to 1 all analogs recorded in fakts and considered suitable for large scale architectural characterization and 2 a subset of them including only systems interpreted as braided

the caucasus an actual example of the initial stages of continental collision abstract a field study of the neotectonics of the georgian caucasus is combined with geophysical geodetic and geological information in order to obtain a mechanical model of actual deformation the analysis of satellite photos together with topographical and geological maps shows that the great caucasus is bisected by a nne trending sinistral strike slip fault zone the western great caucasus is thrusted to the south over the rioni basin while on the other hand its northern flank is a monocline that descends gently into the russian platform active volcanism is present from elbruz to kazbeg the eastern great caucasus is limited by thrusts to the north and to the south and intermediate structures are disposed in a fan like shape no recent volcanism is observed the eastern limit of the chain is a nnw trending dextral strike slip fault zone seismicity from a local network illustrates the activity of the thrusts and gives evidence for the strike slip faults microtectonic data confirm the recent activity and the sinistral character of the borjomi kazbeg strike slip fault the strike slip faults bordering the eastern caucasus may be seen as the limits of a plastic wedge in front of the arabian plate at an early stage of continental collision

the kauai near source test knst modeling and measurements of downslope propagation near the north pacific acoustics laboratory npal kauai source in april 2002 a series of recordings were taken near the north pacific acoustic laboratory npal kauai source this source transmits broadband low frequency signals to receivers in various locations across the pacific travel time calculations based upon the nonbottom interacting pe or ray trace modeling for the kauai source lagged the actual first arrival by 1 second or so a disturbing discrepancy that needed answering the kauai near source test knst was designed to take measurements near the kauai source to examine the effect of the local bathymetry on the signal transmitted into the ocean six receptions using a 100 m vla at ranges from 0 2 to 52 km were taken parabolic equation pe simulations of the channel impulse response for the measurement ranges are in good agreement with the observations pe simulations using an exposed basalt seafloor match the data much better than those with a silty sand cover a primary result of this test was the indication that there may be significant energy in the first bottom bounce comparable to the direct path purely refracted ray this implies that the seafloor near the source influences the arrival times and patterns of the field at long distances and should be taken into account

extension in nw iran driven by the motion of the south caspian basin contrasted tectonic styles occur in northern iran west of kopet dagh the south caspian basin is an aseismic and possibly rigid blockinvolved inthecollisionzonebetweeneurasiaandarabia tothenw largescalevelocityfield ofirangivenbyrecentrepeated gps surveys suggests 8 mm yr of right lateral displacement for the wnw ese faults in the tabriz region more surprisingly geodetic motion also suggests a prominent n 30 extension north to the tabriz fault where compression would be expected in order to quantify more precisely the right lateral movement of the tabriz region the extension of nw iran and the motion of the south caspian basin we deployed a dense gps network in nw iran from central iran to the turkish armenian and azerbaijan borders three repeated surveys from 2002 to 2004 assess that the tabriz fault concentrates entirely the 8 mm yr of right lateral movement observed in nw iran this rate is in good agreement with a recurrence interval time of 250 300 yr proposed from historical seismicity studies we found also two zones of extension one just north of the tabriz fault in the south of the talesh plateau and another close from the azerbaijan border north of the talesh plateau we suggest that the existence of a northward subduction of the south caspian basin could explain such an extension in the core of the arabia eurasia collision increasing evidences of quaternary extensional tectonics in the region from armenia to alborz may lead to significantly alter our understanding of the northern iran tectonics and challenge the traditional arabian indenter plate tectonics

a test of basin scale acoustic thermometry using a large aperture vertical array at 3250 km range in the eastern north pacific ocean broadband acoustic signals were transmitted during november 1994 from a 75 hz source suspended near the depth of the sound channel axis to a 700 m long vertical receiving array approximately 3250 km distant in the eastern north pacific ocean the early part of the arrival pattern consists of raylike wave fronts that are resolvable identifiable and stable the later part of the arrival pattern does not contain identifiable raylike arrivals due to scattering from internal wave induced sound speed fluctuations the observed ray travel times differ from ray predictions based on the sound speed field constructed using nearly concurrent temperature and salinity measurements by more than a priori variability estimates suggesting that the equation used to compute sound speed requires refinement the range averaged ocean sound speed can be determined with an uncertainty of about 0 05 m s from the observed ray travel times together with the time at which the near axial acoustic reception ends used as a surroga

identifying discrete geologic structures that produce anomalous hydraulic response an inverse modeling approach 1 subsurface hydraulic response is controlled by discrete geologic structures in a variety of aquifer settings in this work we analyze data from the well studied alluvial fan system that underlies the lawrence livermore national laboratory there subsurface flow and transport behavior is strongly influenced by discrete channel deposits which are embedded within less permeable floodplain deposits we model the distribution of these deposits using a multiple point geostatistical approach that enables simulation of geologically plausible connected permeable bodies consistent with a training image by coupling the geostatistical model with a dynamic flow model in a simulation inversion framework we identify specific channel structures that are consistent with transient aquifer test data at six observation wells we perform shortest path analysis to characterize the geometry of the simulated channels and to locate critical high permeability conduits that control the system s response to pumping in one area all successful inverse solutions identify the same set of stacked channel deposits a geologic feature that provides an explanation for anomalous response behavior observed during the aquifer test

resonant diurnal internal tides in the north atlantic using a large acoustical array located midway between puerto rico and bermuda we have observed enhanced diurnal tidal signals associated with the lowest internal wave mode these signals result from a diurnal internal wave resonantly trapped between the shelf just north of puerto rico and the turning latitude a distance of about 1100 km the data obtained using the large acoustical array are consistent with the predicted airy function variation with latitude of diurnal internal waves near the turning latitude the existence of this wave is a striking demonstration of the long spatial and temporal coherence of oceanic internal tides in general the energy radiated by such waves is a loss of energy from the earth moon system and a source of energy for mixing in the deep ocean

closing the gap between regional and global travel time tomography recent global travel time tomography studies by zhou 1996 and van der hilst et al 1997 have been performed with cell parameterizations of the order of those frequently used in regional tomography studies i e with cell sizes of 1 2 these new global models constitute a considerable improvement over previous results that were obtained with rather coarse parameterizations 5 cells the inferred structures are however of larger scale than is usually obtained in regional models and it is not clear where and if individual cells are actually resolved this study aims at resolving lateral heterogeneity on scales as small as 0 6 in the upper mantle and 1 2 3 in the lower mantle this allows for the adequate mapping of expected small scale structures induced by for example lithosphere subduction deep mantle upwellings and mid ocean ridges there are three major contributions that allow for this advancement first we employ an irregular grid of nonoverlapping cells adapted to the heterogeneous sampling of the earth s mantle by seismic waves spakman and bijwaard 1998 second we exploit the global data set of engdahl et al 1998 which is a reprocessed version of the global data set of the international seismological centre their reprocessing included hypocenter redetermination and phase reidentification finally we combine all data used p pp and pwp phases into nearly 5 million ray bundles with a limited spatial extent such that averaging over large mantle volumes is prevented while the signal to noise ratio is improved in the approximate solution of the huge inverse problem we obtain a variance reduction of 57 1 synthetic sensitivity tests indicate horizontal resolution on the scale of the smallest cells 0 6 or 1 2 in the shallow parts of subduction zones decreasing to approximately 2 3 resolution in well sampled regions in the lower mantle vertical resolution can be worse up to several hundreds of kilometers in subduction zones with rays predominantly pointing along dip important features of the solution are as follows 100 200 km thick high velocity slabs beneath all major subduction zones sometimes flattening in the transition zone and sometimes directly penetrating into the lower mantle large high velocity anomalies in the lower mantle that have been attributed to subduction of the tethys ocean and the farallon plate and low velocity anomalies continuing across the 660 km discontinuity to hotspots at the surface under iceland east africa the canary islands yellowstone and the society islands our findings corroborate that the 660 km boundary may resist but not prevent present day large scale mass transfer from upper to lower mantle or vice versa this observation confirms the results of previous global mantle studies that employed coarser parameterizations

an approach for measuring confinement and assessing the influence of valley setting on river forms and processes valley setting and confinement or lack thereof are primary controls on river character and behaviour although there are various proxies for valley confinement direct measures that quantify the nature and extent of confinement are generally lacking and or inconsistently described as such they do not lend themselves to consistent analysis over large spatial scales here we clearly define forms of confinement to aid in quantification of degrees of confinement types of margin that can induce confinement are differentiated as a valley margin valley bottom margin and or anthropogenic margin such margins sometimes overlap and share the same location and in other situations are separated giving immediate clues as to the valley setting we apply this framework to examples from australia united states and new zealand showing how this framework can be applied across the spectrum of river diversity this method can help to inform interpretations of reach scale river behaviour highlighting the role of antecedent controls on contemporary forms and processes clear definitions of confinement are shown to support catchment scale analysis of river patterns along longitudinal profiles and appraisals of the geomorphic effectiveness of floods and sediment flux in catchments e g process zone distribution lateral sediment inputs and dis connectivity copyright 2015 john wiley sons ltd

acoustic tomography in the canary basin meddies and tides an acoustic propagation experiment over 308 km range conducted in the canary basin in 1997 1998 was used to assess the ability of ocean acoustic tomography to measure the flux of mediterranean water and meddies instruments on a mooring adjacent to the acoustic path measured the southwestward passage of a strong meddy in temperature salinity and current over nine months of transmissions the acoustic arrival pattern was an initial broad stochastic pulse varying in duration by 250 to 500 ms followed eight stable identified ray arrivals small scale sound speed fluctuations from mediterranean water parcels littered around the sound channel axis caused acoustic scattering internal waves contributed more modest acoustic scattering based on simulations the main effect of a meddy passing across the acoustic path is the formation of many early arriving near axis rays but these rays are thoroughly scattered by the small scale mediterranean water fluctuations a meddy decreases the deep turning ray travel times by 10 30 ms the dominant acoustic signature of a meddy is therefore the expansion of the width of the initial stochastic pulse while this signature appears inseparable from the other effects of mediterranean water in this region the acoustic time series indicates the steady passage of mediterranean water across the acoustic path tidal variations caused by the mode 1 internal tides were measured by the acoustic travel times the observed internal tides were partly predicted using a recent global model for such tides derived from satellite altimetry

the effect of bottom interaction on transmissions from the north pacific acoustic laboratory kauai source acoustic signals transmitted from a 75 hz broadband source near kauai as part of the north pacific acoustic laboratory npal experiment were recorded on an array of receivers near california at a range of 3890 km and on a vertical line array at a range of 3336 km in the gulf of alaska because the source is approximately 2 m above the seafloor and the bottom depth at the receivers near california is approximately 1800 m acoustic interaction with the bathymetry complicates the identification of the recorded arrivals with those present in numerical simulations of the experiment ray methods were used to categorize acoustic energy according to interactions with the sea bottom and surface and to examine the significance of seafloor geometry a modal decomposition was also used to examine the role of range dependent bathymetry and to associate the effects on the acoustic field with seafloor features at specific ranges parabolic equation simulations were performed in order to investigate the sensitivity of

holocene historical volcanism and active faults as natural risk factors for armenia and adjacent countries abstract examples of holocene historical volcanism in the territory of armenia and adjacent areas of eastern anatolia and western iran are discussed holocene historical activity is proved for the volcanoes of tskhouk karckar porak vaiyots sar smbatassar and ararat based on the analysis of remote sensing data field work and historical and archeological information it is demonstrated that there was a considerable number of cases of volcanic activity in armenia and adjacent regions of turkey syria and iran during the historical period the holocene volcanic centers are situated within pull apart basin structures and controlled by active faults situated in an area prone to many types of natural hazards armenia and adjacent countries face high natural risk the evidence presented shows that volcanic hazard also contributes to the natural risk for these countries

three dimensional observations of a deep convective chimney in the greenland sea during winter 1988 89 abstract all available temperature data including moored thermistor hydrographic and tomographic measurements have been combined using least squares inverse methods to study the evolution of the three dimensional temperature field in the greenland sea during winter 1988 89 the data are adequate to resolve features with spatial scales of about 40 km and larger a chimney structure reaching depths in excess of 1000 m is observed to the southwest of the gyre center during march 1989 the chimney has a spatial scale of about 50 km near the limit of the spatial resolution of the data and a timescale of about 10 days the chimney structure breaks up and disappears in only 3 6 days a one dimensional vertical heat balance adequately describes changes in total heat content in the chimney region from autumn 1988 until the time of chimney breakup when horizontal advection becomes important a simple one dimensional mixed layer model is surprisingly successful in reproducing autumn to winter bulk temperatur

surface waveform tomography of the turkish iranian plateau summary the middle east is a tectonically complex region consisting of terrains as diverse as precam brian shields and young orogens the dominant tectonic feature is the turkish iranian plateau a recently elevated seismically active region along the zagros bitlis suture which results from the collision of the arabian plate with eurasia in this study we use surface waveform tomography to elucidate the upper mantle shear wave velocity structure beneath the turkish iranian plateau and adjacent regions the main large scale feature in the tomographic model is a low shear wave velocity anomaly in the uppermost mantle beneath the plateau this low velocity feature correlates with a long wavelength free air gravity anomaly and with recent volcanism whose geochemistry has a lower lithospheric mantle signature seismology gravity and volcanism all suggest the presence of a thin lithosphere and warm upper mantle beneath the turkish iranian plateau the upper mantle low shear wave velocity zone the high free air gravity and the deep lithospheric source depth for the basaltic volcanism are all consistent with a partial delamination of the lithosphere as a result of earlier lithospheric thickening resulting from the continental collision

assessing the horizontal refraction of ocean acoustic tomography signals using high resolution ocean state estimates the analysis of signals for acoustic tomography sent between a source and a receiver most often uses the unrefracted geodesic path an approximation that is justified from theoretical considerations relying on estimates of horizontal gradients of sound speed or on simple theoretical models to quantify the effects of horizontal refraction caused by a realistic ocean environment horizontal refractions of long range signals were computed using global ocean state estimates for 2004 from the estimating the circulation and climate of the ocean ecco2 project basin scale paths in the eastern north pacific ocean and regional scale paths in the philippine sea were used as examples at o 5 mm basin scales refracted geodesic and geodesic paths differed by only about 5 km gyre scale features had the greatest refractive influence but the precise refractive effects depended on the path geometry with respect to oceanographic features refraction decreased travel times by 5 10 ms and changed azimuthal angles by about 0 2 at o 500 km regional scales paths deviated from the geodesic by only 250 m and travel times deviated by less than 0 5 ms such effects are of little consequence in the analysis of tomographic data refraction details depend only slightly on mode number and frequency

stratigraphy and static connectivity of braided fluvial deposits of the lower escanilla formation south central pyrenees spain this study addressed the architecture and dimension distributions of fluvial deposits of the olson member of the escanilla formation through analysis of outcrops in the southern buil syncline ainsa basin south central pyrenees spain the olson member consists of wide multistory channels alternating with mud rich intervals composed of flood plain deposits and isolated individual channels field descriptions and a combination of terrestrial light detection and ranging data and digital orthophotographs were used to map and document the abundance distribution and dimensions of sandstone bodies these data show that channels are distributed according to the local stratigraphic framework and differential subsiding areas morphology width depth and sinuosity of the channels throughout the sequence evolve according to their stratigraphic position during low accommodation periods channels stacked laterally forming wide multistory channel belts under these conditions single channels have a mean width to thickness w t ratio of 49 during high accommodation periods single channels have a mean w t ratio of 29 moreover the tendency of narrower and thicker channels having developed during high accommodation periods is also clearly observable vertically from the base to the top of high accommodation intervals throughout the sequence this pattern of deposition results in increasing vertical connectivity even in mud rich high accommodation periods a geocellular three dimensional model has been performed using object based simulations a succession of stochastic simulations was performed from the simplest one random simulations to more elaborated simulations integrating successively outcrop observations these simulations serve to image sandstone bodies connectivity evolution according to outcrop observations and sedimentologic knowledge subsurface application of such vertical channel morphology evolutions and distribution could lead to more predictive flow unit definitions and extensions

on the time mean state of ocean models and the properties of long range acoustic propagation 1 receptions on three vertical hydrophone arrays from basin scale acoustic transmissions in the north pacific during 1996 and 1998 are used to test the time mean sound speed properties of the world ocean atlas 2005 woa05 of an eddying unconstrained simulation of the parallel ocean program pop and of three data constrained solutions provided by the estimating the circulation and climate of the ocean ecco project a solution based on an approximate kalman filter from the jet propulsion laboratory ecco jpl a solution based on the adjoint method from the massachusetts institute of technology ecco mit and an eddying solution based on a green s function approach from ecco phase ii ecco2 predictions for arrival patterns using annual average woa05 fields match observations to within small travel time offsets 0 3 1 0 s predictions for arrival patterns from the models differ substantially from the measured arrival patterns from the woa05 climatology and from each other both in terms of travel time and in the structure of the arrival patterns the acoustic arrival patterns are sensitive to the vertical gradients of sound speed that govern acoustic propagation basin scale acoustic transmissions therefore provide stringent tests of the vertical temperature structure of ocean state estimates this structure ultimately influences the mixing between the surface waters and the ocean interior the relatively good agreement of the acoustic data with the more recent ecco solutions indicates that numerical ocean models have reached a level of accuracy where the acoustic data can provide useful additional constraints for ocean state estimation

the role of simulated small scale ocean variability in inverse computations for ocean acoustic tomography ocean acoustic tomography depends on a suitable reference ocean environment with which to set the basic parameters of the inverse problem some inverse problems may require a reference ocean that includes the small scale variations from internal waves small mesoscale or spice tomographic inversions that employ data of stable shadow zone arrivals such as those that have been observed in the north pacific and canary basin are an example estimating temperature from the unique acoustic data that have been obtained in fram strait is another example the addition of small scale variability to augment a smooth reference ocean is essential to understanding the acoustic forward problem in these cases rather than a hindrance the stochastic influences of the small scale can be exploited to obtain accurate inverse estimates inverse solutions are readily obtained and they give computed arrival patterns that matched the observations the approach is not ad hoc but universal and it has allowed inverse estima

estimating range to a vocalizing fin whale using the timing and amplitude of multipath arrivals a semi automated method is described to range to vocalizing fin whales using the timing and amplitude of multipath arrivals measured on seafloor receivers calls are detected and multipath arrivals identified with a matched filter multipath times and relative amplitudes are predicted as a function of range by ray tracing because the direct and first water column multiple arrivals are not always observed different hypotheses for the observed arrival paths must be considered for two arrivals an amplitude threshold is used to determine if the first arrival is the direct path and if not the call is disregarded as distant when three or more arrivals are detected three hypotheses for the paths of arrivals are considered the solution is the hypothesis and range that minimizes the timing and optionally amplitude ratio or absolute amplitude residual the method is tested with data from two ocean bottom seismometers one on the juan de fuca ridge and the other in the cascadia basin solutions obtained by

present day crustal deformation and plate kinematics in the middle east constrained by gps measurements in iran and northern oman summary a network of 27 gps sites was implemented in iran and northern oman to measure displacements in this part of the alpine himalayan mountain belt we present and interpret the results of two surveys performed in 1999 september and 2001 october gps sites in oman show northward motion of the arabian plate relative to eurasia slower than the nuvel 1a estimates e g 22 2m m yr 1 at n8 5 e instead of 30 5 mm yr 1 at n6 e at bahrain longitude we define a gps arabia eurasia euler vector of 27 9 0 5 n 19 5 1 4 e 0 41 0 1 myr 1 the arabia eurasia convergence is accommodated differently in eastern and western iran east of 58 e most of the shortening is accommodated by the makran subduction zone 19 5 2m m yr 1 and less by the kopet dag 6 5 2m m yr 1 west of 58 e the deformation is distributed in separate fold and thrust belts at the longitude of tehran the zagros and the alborz mountain ranges accommodate 6 5 2m m yr 1 and 8 2m m yr 1 respectively the right lateral displacement along the main recent fault in the northern zagros is about 3 2m m yr 1 smaller than what was generally expected by contrast large rightlateral displacement takes place in northwestern iran up to 8 mm yr 1 the central iranian block is characterized by coherent plate motion internal deformation 2m m yr 1 sites east of 61 e show very low displacements relative to eurasia the kinematic contrast between eastern and western iran is accommodated by strike slip motions along the lut block to the south the transition zone between zagros and makran is under transpression with right lateral displacements of 11 2m m yr 1

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

late cenozoic reorganization of the arabia eurasia collision and the comparison of short term and long term deformation rates the arabia eurasia collision deforms an area of 3 000 000 km2 of continental crust making it one of the largest regions of convergent deformation on earth there are now estimates for the active slip rates total convergence and timing of collision related deformation of regions from western turkey to eastern iran this paper shows that extrapolating the present day slip rates of many active fault systems for 3 7 million years accounts for their total displacement this result means that the present kinematics of the arabia eurasia collision are unlikely be the same as at its start which was probably in the early miocene 16 23 ma or earlier in some but not all active fault systems short term 10 year and long term 5 million year average deformation rates are consistent there is little active thickening across the turkish iranian plateau and possibly the interior of the greater caucasus these are two areas where present shortening rates would need more than 7 million years to account for the total crustal thickening and where there are structural and or stratigraphic data for pre late miocene deformation we suggest that once thick crust up to 60 km built up in the turkish iranian plateau and the greater caucasus convergence took place more easily by crustal shortening in less elevated regions such as the zagros simple folded zone the south caspian region and foothills of the greater caucasus or in other ways such as westward transport of turkey between the north and east anatolian faults the time and duration of this changeover are not known for certain and are likely be diachronous although deformation started or intensified in many of the currently active fault systems at 5 2 ma

gps constraints on continental deformation in the africa arabia eurasia continental collision zone and implications for the dynamics of plate interactions 1 the gps derived velocity field 1988 2005 for the zone of interaction of the arabian african nubian somalian and eurasian plates indicates counterclockwise rotation of a broad area of the earth s surface including the arabian plate adjacent parts of the zagros and central iran turkey and the aegean peloponnesus relative to eurasia at rates in the range of 20 30 mm yr this relatively rapid motion occurs within the framework of the slow moving 5 mm yr relative motions eurasian nubian and somalian plates the circulatory pattern of motion increases in rate toward the hellenic trench system we develop an elastic block model to constrain present day plate motions relative euler vectors regional deformation within the interplate zone and slip rates for major faults substantial areas of continental lithosphere within the region of plate interaction show coherent motion with internal deformations below 1 2 mm yr including central and eastern anatolia turkey the southwestern aegean peloponnesus the lesser caucasus and central iran geodetic slip rates for major block bounding structures are mostly comparable to geologic rates estimated for the most recent geological period 3 5 myr we find that the convergence of arabia with eurasia is accommodated in large part by lateral transport within the interior part of the collision zone and lithospheric shortening along the caucasus and zagros mountain belts around the periphery of the collision zone in addition we find that the principal boundary between the westerly moving anatolian plate and arabia east anatolian fault is presently characterized by pure left lateral strike slip with no fault normal convergence this implies that extrusion is not presently inducing westward motion of anatolia on the basis of the observed kinematics we hypothesize that deformation in the africa arabia eurasia collision zone is driven in large part by rollback of the subducting african lithosphere beneath the hellenic and cyprus trenches aided by slab pull on the southeastern side of the subducting arabian plate along the makran subduction zone we further suggest that the separation of arabia from africa is a response to plate motions induced by active subduction

a topex poseidon global tidal model tpxo 2 and barotropic tidal currents determined from long range acoustic transmissions abstract tidal currents derived from the tpxo 2 global tidal model of egbert bennett and foreman are compared with those determined from long range reciprocal acoustic transmissions amplitudes and phases of tidal constituents in the western north atlantic are derived from acoustic data obtained in 1991 1992 using a pentagonal array of transceivers small spatially coherent differences between the measured and modeled tidal harmonic constants mostly result from smoothing assumptions made in the model and errors caused in the model currents by complicated topography to the southwest of the acoustical array acoustically measured harmonic constants amplitude phase of m2 tidal vorticity 3 8 10 9s 1 210 310 agree with those derived from the tpxo 2 model 2 5 10 9s 1 250 300 whereas harmonic constants of about 1 2 10 9s 1 350 360 are theoretically expected from the equations of motion harmonic constants in the north pacific ocean are determined using acoustic data from a triangular transceiver array deployed in 1987 these constants are consistent with those given by the tpxo 2 tidal model within the uncertainties tidal current harmonic constants determined from current meters do not generally provide a critical test of tidal models the tidal currents have been estimated to high accuracy using long range reciprocal acoustic transmissions these estimates will be useful constraints on future global tidal models

effects of spatially variable accommodation rate on channel belt distribution in an alluvial sequence authigenic 10be 9be based bayesian age depth models applied to the upper miocene volkovce fm northern pannonian basin system slovakia abstract relationships between spatially variable accommodation rate and the distribution of channel belt deposits are important issues in alluvial stratigraphy this segment of sedimentology still records important progress using experimental models and field examples this study focuses on the alluvial stratigraphy of the volkovce fm which was deposited between 9 0 6 0 ma in the northern pannonian basin system and it provides an excellent natural laboratory to study this topic the spatial variability of channel belt distribution was determined in 809 borehole logs drilled to 200 300 m depths while the facies associations were defined on the outcrops a significant variance in channel belt content was observed since it reaches 10 40 of the stratigraphic column in the southwestern part of the study area and only 0 15 in the northeastern portion moreover the transition between the areas of different channel belt distribution is oriented perpendicular to the paleo drainage network axis geochronology was then established by applying the authigenic 10be 9be dating method to three borehole cores the bayesian age depth models used herein proved a decrease in average accommodation rates from 200 m myr to 50 m myr towards the area with

deciphering oblique shortening of central alborz in iran using geodetic data the alborz is a narrow 100 km and elevated 3000 m mountain belt which accommodates the differential motion between the sanandaj sirjan zone in central iran and the south caspian basin gps measurements of 12 geodetic sites in central alborz between 2000 and 2002 allow to constrain the motion of the belt with respect to western eurasia one site velocity on the caspian shoreline suggests that the south caspian basin moves northwest at a rate of 6 2 mm year with respect to western eurasia north south shortening across the alborz occurs at 5 2 mm year to the south deformation seems to extend beyond the piedmont area probably due to active thrusting on the pishva fault we also observe a left lateral shear of the overall belt at a rate of 4 2 mm year consistent with the geological motion observed along e w active strike slip faults inside the belt e g the mosha fault

the geometry of fluvial channel bodies empirical characterization and implications for object based models of the subsurface the distribution of channel deposits in fluvial reservoirs is commonly modeled with object based techniques constrained on quantities describing the geometries of channel bodies to ensure plausible simulations it is common to define inputs to these models by referring to geologic analogs given their ability to reproduce complex geometries and to draw upon the analog experience object based models are considered inherently realistic yet this perceived realism has not hitherto been tested by assessing the outputs of these techniques against sedimentary architectures in the stratigraphic record this work presents a synthesis of data on the geometry of channel bodies derived from a sedimentologic database with the following aims 1 to provide tools for constraining stochastic models of fluvial reservoirs in data poor situations and 2 to test the intrinsic realism of object based modeling algorithms by comparing characteristics of the modeled architectures against analogs an empirical characterization of the geometry of fluvial channel bodies is undertaken that describes distributions in and relationships among channel body thickness cross stream width and planform wavelength and amplitude object based models are then built running simulations conditioned on six alternative analog informed parameter sets using four algorithms according to nine different approaches closeness of match between analogs and models is then determined on a statistical basis results indicate which modeling approaches return architectures that more closely resemble the organization of fluvial depositional systems known from nature and in what respect none of the tested algorithms fully reproduce characteristics seen in natural systems demonstrating the need for subsurface modeling methods to better incorporate geologic knowledge