resolving three dimensional surface displacements from insar measurements a review abstract one dimensional measurement along the line of sight los direction has greatly limited the capability of insar technique in the investigation of surface displacements and their dynamics in recent years great efforts have been made to resolve complete three dimensional 3 d displacements from insar measurements this contribution is intended to provide a systematic review of the progress achieved in this field based on an analysis of the insar los measurements we first cover two commonly used techniques i e offset tracking and multi aperture insar mai with which the surface displacement in the azimuth direction can be measured together with the los displacement several methods for mapping 3 d displacements using insar measurements are subsequently presented and categorized into three groups i combination of multi pass los and azimuth measurements ii integration of insar and gps data and iii prior information assisted approaches the strengths and weaknesses of each method are analyzed to show the applicability of each method to specific 3 d displacement mapping cases in hope to provide a useful guidance in choosing a suitable approach accordingly finally suggestions for resolving the challenging issues and outlook of future research are given

an alternative interpretation of the cayman trough evolution from a reidentification of magnetic anomalies magnetic data were collected during the wilkes 1973 and seacarib ii 1987 cruises to the cayman trough a new interpretation of magnetic data is carried out an isochron pattern is drawn up from our anomaly identifications an early eocene age 49 ma ypresian for cayman trough opening is proposed instead of the late oligocene or middle eocene ages suggested by previous studies our plate tectonic reconstruction is simpler and fits the on land geology jamaica and cuba and the tectonics our reconstruction shows a southward propagation of the spreading centre between magnetic anomalies 8 and 6 26 and 20 ma the trough width increases by 30 km in this period the southward propagation of the cayman spreading centre from the middle oligocene to the early miocene induced the development of the restraining bend of the swan islands the formation of a 1 km high scarp on the eastern trace of the cayman trough transform fault walton fault and the formation of a pull apart basin hendrix pull apart magnetic anomalies and magnetization maps give information about the deformation and the rocks the proposed evolutionary model of the cayman trough from the inception of seafloor spreading to the present configuration is presented in relation to the tectonic escape of the northern boundary of the caribbean plate from the maastrichtian to the present

sedimentary pyrite formation an update sedimentary pyrite formation during early diagenesis is a major process for controlling the oxygen level of the atmosphere and the sulfate concentration in seawater over geologic time the amount of pyrite that may form in a sediment is limited by the rates of supply of decomposable organic matter dissolved sulfate and reactive detrital iron minerals organic matter appears to be the major control on pyrite formation in normal non euxinic terrigenous marine sediments where dissolved sulfate and iron minerals are abundant by contrast pyrite formation in non marine freshwater sediments is severely limited by low concentrations of sulfate and this characteristic can be used to distinguish ancient organic rich fresh water shales from marine shales under marine euxinic conditions sufficient h2s is produced that the dominant control on pyrite formation is the availability of reactive iron minerals calculations based on a sulfur isotope model indicate that over phanerozoic time the worldwide average organic carbon to pyrite sulfur ratio of sedimentary rocks has varied considerably high cs ratios during permo carboniferous time can be explained by a shift of major organic deposition from the oceans to the land which resulted in the formation of vast coal swamps at that time low cs ratios compared to today during the early paleozoic can be explained in terms of a greater abundance of euxinic basins combined with deposition of a more reactive type of organic matter in the remaining oxygenated portions of the ocean the latter could have been due to lower oceanic oxygen levels and or a lack of transportation of refractory terrestrial organic matter to the marine environment due to the absence of vascular land plants at that time

diagenesis of siliciclastic and volcaniclastic sediments in the cretaceous and miocene sequences of the nw african margin dsdp leg 47a site 397 abstract the lower cretaceous and miocene sequences of the nw african passive continental margin consist of siliciclastic volcaniclastic and hybrid sediments these sediments contain a variety of diagenetic carbonates associated with zeolites smectite clays and pyrite reflecting the detrital mineralogical composition and conditions which prevailed during opening of the north atlantic in the lower cretaceous siliciclastic sediments siderite 6 to 0 7 18 o pdb 19 6 to 0 6 13 c pdb was precipitated as thin layers and nodules from modified marine porewaters with input of dissolved carbon from the alteration of organic matter microcrystalline dolomite layers lenses nodules and disseminated crystals 3 0 to 2 5 18 o pdb 7 2 to 4 9 13 c pdb predominate in slump and debris flow deposits within the lower miocene sequence during the opening of the atlantic volcanic activity in the canary islands area resulted in input of volcaniclastic sediments to the middle and upper miocene sequences calcite is the dominant diagenetic carbonate in the siliciclastic bioclastic volcaniclastic hybrid and in the volcaniclastic sediments which commonly contain pore rimming smectite diagenetic calcite 22 to 1 6 18 o pdb 35 7 to 0 8 13 cpdb was precipitated due to the interaction of volcaniclastic and bioclastic grains with marine porewaters phillipsite is confined to the alteration of volcaniclastic sediments whereas clinoptilolite is widely disseminated occurring essentially within foraminiferal chambers and formed due to the dissolution of biogenic silica

hiatal duration of correlative sequence boundaries from oligocene pliocene mixed carbonate siliciclastic sediments of the south florida platform abstract sequence boundaries defined by regional unconformities in mixed carbonate siliciclastic sediments have a variable duration from the margin to the interior of the florida platform factors controlling the timing and duration of these unconformities include a combination of global eustatic and regional mechanisms sediment supply current intensification integrated chronostratigraphies developed from a transect of continuous cores in the south central interior to the southern margin of the florida platform show an increase in duration of the hiatal gaps along correlative sequence boundaries toward the platform edge two sequence boundaries are correlated across the south florida platform and mark formation contacts the lower sequence boundary sb a marks the suwannee limestone arcadia formation contact and is of significantly less duration in the platform interior southwest peninsular florida 2 0 m y than at the south platform margin middle florida keys 8 1 m y the hiatal gap along the upper sequence boundary sb b marking the arcadia formation overlain by miocene pliocene sediments that vary in age and composition regionally records the same increase from the central part of the platform southwest florida arcadia fm peace river fm 1 6 m y to the south platform edge lower florida keys arcadia fm stock island fm 11 5 m y eustatic fluctuations affected the relative sedimentation rates of the mixed sediments in the platform interior and at the margin most notably the large eustatic fall at the end of the early oligocene terminated carbonate deposition of the suwannee limestone sb a sediment accumulation on the platform interior was more temporally continuous than at the margin because of greater siliciclastic input from the north the strengthening of marine currents beginning in the middle miocene limited sediment accumulation across the southern platform margin sb b and possibly caused erosion of the margin carbonates increasing the duration of the hiatal gap on top of the arcadia formation

kalman filter based approach for multisensor multitrack and multitemporal insar a kalman filter based approach is presented for resolving 3 d surface displacements using multisensor multitrack and multitemporal interferometric synthetic aperture radar sar measurements measurements from each interferogram are projected into the three reference directions and combined in the kalman filter model with displacements determined from previous interferograms to produce updated displacement measurements both simulated and real data sets are used to test the proposed approach it is found that the method works well when the measurement noise is low the displacements in the north direction however are much lower in accuracy than those in the other two directions and even become unstable when the measurement noise is high due to the polar orbiting imaging geometries of the current satellite sar sensors

formation processes of framboidal pyrite abstract pyrite framboid formation may be the result of four consecutive processes 1 nucleation and growth of initial iron monosulfide microcrystals 2 reaction of the microcrystals to greigite fe 3 s 4 3 aggregation of uniformly sized greigite microcrystals i e framboid growth and 4 replacement of greigite framboids by pyrite the uniform morphology uniform size range and ordering of the microcrystals in individual framboids as well as the range of observed framboid structures from irregular aggregates to densely packed spherical aggregates and polyframboids are consequences of these processes using dlvo theory derjaguin landau verwey and overbeek we have evaluated the stability of colloidal iron monosulfide suspensions with ionic strengths typical of marine and lacustrine waters in addition to van der waals attractive and double layer repulsive forces a term is included to account for the ferrimagnetic properties of greigite numerical models predict that magnetically saturated greigite particles 0 1 m in diameter will rapidly aggregate in either marine or fresh water the aggregation model is in agreement with the sequence of greigite formation followed by pyrite framboid formation established in a previous experimental study sweeney and kaplan 1973 and is consistent with the occurrence of framboids composed of other magnetic minerals e g greigite magnetite and magnesioferrite based on the temperature dependent magnetic properties of greigite and aging experiments in hydrothermal solutions this mechanism for framboid formation via precursor greigite could operate to temperatures of 200 c consistent with the occasional occurrence of pyrite framboids in the paragenesis of metalliferous ore deposits

simulation of the supersar multi azimuth synthetic aperture radar imaging system for precise measurement of three dimensional earth surface displacement the supersar imaging system a novel multi azimuth synthetic aperture radar sar system capable of detecting earth surface deformation in three dimensions from a single satellite platform has recently been proposed in this paper we investigate the feasibility of detecting precise 3 d surface displacement measurements with the supersar imaging system using a point target simulation from this simulation we establish both a relationship between the interferometric sar phase and the across track displacement and a relationship between the multiple aperture interferometry phase and the along track displacement based on the supersar imaging geometry the theoretical uncertainties of the supersar measurement are analyzed in the across and along track directions and the theoretical accuracy of the 3 d displacement measurement from the supersar system is also investigated according to both the decorrelation and the squint and look angles in the case that the interferometric coherence is about 0 8 and that five effective looks are employed the theoretical 2 d measurement precision values are about 3 67 and 6 35 mm in the across and along track directions respectively and the theoretical 3 d measurement precision values for 3 d displacement are about 4 05 4 56 and 3 45 mm in the east north and up directions respectively the result of this study demonstrates that the supersar imaging system is capable of measuring the 3 d surface displacement in all directions with subcentimeter precision

origin of clay rich beds in turonian chalks from lower saxony germany a rare earth element study abstract the mineralogy and ree geochemistry of thin clay rich beds from turonian chalks of lower saxony germany has been studied two types of clay rich beds are present the first is of volcanic origin and is characterised by 1 a ree signature similar to marine argillized volcanic ash bands and 2 a silicate mineralogy dominated by smectite with minor corrensite the second type is of continental origin and is characterised by 1 a ree signature similar to continental shale and 2 a silicate mineralogy dominated by smectite with minor heulandite clinoptilolite the use and misuse of these widespread clay rich horizons in the turonian stratigraphy of lower saxony is discussed

coseismic three dimensional displacements determined using sar data theory and an application test we present a methodology to construct three dimensional deformation maps using different parameters that can be extracted using sar data we apply the methodology using envisat sar data before and after the december 26 th 2003 mw 6 6 bam earthquake in iran to determine spatial quasi continuous three dimensional coseismic deformation maps two near vertical deformation offset components are computed using envisat asar differential interferometry dinsar while two horizontal deformation offset components are measured using sub pixel correlation techniques applied to asar amplitude images using the presented methodology we combine four unevenly precise independent projections of surface coseismic deformation to obtain the full three dimensional coseismic deformation field caused by an earthquake the full 3 d coseismic displacement vector is modeled using elastic deformation models constraining details of the fault geometry and slip distribution at depth results from the inversion are interpreted in the framework of the iranian present day tectonism full exploitation of dense 3 d coseismic surface deformation using sar data even for moderate earthquakes should facilitate distinguishing between different interpretations of the mechanical properties of seismically active areas and within the inherent ambiguity of the geophysical inversion solutions

correcting atmospheric effects on insar with meris water vapour data and elevation dependent interpolation model summary the propagation delay when radar signals travel from the troposphere has been one of the major limitations for the applications of high precision repeat pass interferometric synthetic aperture radar insar in this paper we first present an elevation dependent atmospheric correction model for advanced synthetic aperture radar asar the instrument aboard the envisat satellite interferograms with medium resolution imaging spectrometer meris integrated water vapour iwv data then using four asar interferometric pairs over southern california as examples we conduct the atmospheric correction experiments with cloud free meris iwv data the results show that after the correction the rms differences between insar and gps have reduced by 69 6 per cent 29 per cent 31 8 per cent and 23 3 per cent respectively for the four selected interferograms with an average improvement of 38 4 per cent most importantly after the correction six distinct deformation areas have been identified that is long beach santa ana basin pomona ontario san bernardino and elsinore basin with the deformation velocities along the radar line of sight los direction ranging from 20 mm yr 1 to 30 mm yr 1 and on average around 25 mm yr 1 and santa fe springs and wilmington with a slightly low deformation rate of about 10 mm yr 1 along los finally through the method of stacking we generate a mean deformation velocity map of los angeles over a period of 5 yr the deformation is quite consistent with the historical deformation of the area thus using the cloud free meris iwv data correcting synchronized asar interferograms can significantly reduce the atmospheric effects in the interferograms and further better capture the ground deformation and other geophysical signals

depth probability distributions in stream reaches modeling spatial probability distributions of depth in natural stream reaches is of major interest to ecologists analyses of data from a wide range of streams at various stages show that depth probability distributions in reaches tend from exponential to normal with increasing stage this trend is modeled using a simple one parameter density function the model is robust and is a simple tool no topographic sampling nor expensive numerical calculation for predicting the evolution of depth probability distributions as a function of stage

interferometric synthetic aperture radar insar atmospheric correction gps moderate resolution imaging spectroradiometer modis and insar integration atmospheric effects represent one of the major limitations of repeat pass interferometric synthetic aperture radar insar in this paper gps and moderate resolution imaging spectroradiometer modis data were integrated to provide regional water vapor fields with a spatial resolution of 1 km 1 km and a water vapor correction model based on the resultant water vapor fields was successfully incorporated into the jet propulsion laboratory california institute of technology roi pac software the advantage of this integration approach is that only one continuous gps station is required within a 2030 km 1354 km modis scene application to ers 2 repeat pass data over the los angeles southern california integrated gps network scign area shows that this integration approach not only helps discriminate geophysical signals from atmospheric artifacts but also reduces water vapor effects significantly which is of great interest to a wide community of geophysicists

questioning carbonate diagenetic paradigms evidence from the neogene of the bahamas carbonate diagenetic models have been heavily influenced by numerous studies of exposed quaternary limestones as a result meteoric diagenesis is often assumed to be the principle means of altering aragonite rich sediments into calcitic limestones however these models are limited by the scarcity of examples of aragonite rich sediments buried in seawater that have never been influenced by meteoric fluids the bahamas transect cores recovered originally aragonite rich sediments deposited in deep water beyond the easy reach of meteoric waters and provide an opportunity to test current diagenetic paradigms the bahamas transect consists of seven cores drilled in the prograding western margin of great bahama bank the two proximal cores clino and unda were drilled on the platform top and recovered shallow water platform to reef facies overlying deeper margin and proximal slope facies the five distal cores were drilled by odp leg 166 in up to 660 m of water and recovered carbonate slope facies all studied sections are neogene to pleistocene in age diagenetic environments were identified based on petrographic and scanning electron microscopy sem observations xrd mineralogy carbon and oxygen stable isotopic data and trace elements the upper 100 150 m of the two proximal cores were altered in meteoric to mixing zone diagenetic environments but all other intervals were altered exclusively in marine pore fluids during seafloor marineburial and deep burial diagenesis several of the findings of this study question current carbonate diagenetic paradigms these include 1 large scale sea level lowstands may not have chemically active meteoric lenses as we found no meteoric alteration at the 3120 m elevation of the latest pleistocene lowstand rather phreatic meteoric diagenesis appears restricted to within w10 m of the land surface 2 mixing zone diagenesis includes aragonite dissolution and minor lmc cementation but does not show the cavernous porosity or dolomitization predicted by mixing zone diagenetic models current models are based on coastal mixing zones which do not appear to be applicable to these more inland and perhaps more typical locations 3 marine burial diagenesis produces a mature limestone with fabrics formerly considered diagnostic for meteoric diagenesis such as moldic porosity aragonite neomorphism blocky calcite spar and calcite microspar however oxygen stable isotopic data average n 18 o 1x indicate alteration in marine pore fluids only the character of marine burial diagenesis is partially controlled by the nature of the sediment being altered we have identified two end member styles an open system style characterized by dissolution of aragonite without significant cementation and a more closed system style with aragonite dissolution

detection of aquifer system compaction and land subsidence using interferometric synthetic aperture radar antelope valley mojave desert california interferometric synthetic aperture radar insar has great potential to detect and quantify land subsidence caused by aquifer system compaction insar maps with high spatial detail and resolution of range displacement 10 mm in change of land surface elevation were developed for a groundwater basin 103 km2 in antelope valley california using radar data collected from the ers 1 satellite these data allow comprehensive comparison between recent 1993 1995 subsidence patterns and those detected historically 1926 1992 by more traditional methods the changed subsidence patterns are generally compatible with recent shifts in land and water use the insar detected patterns are generally consistent with predictions based on a coupled model of groundwater flow and aquifer system compaction the minor inconsistencies may reflect our imperfect knowledge of the distribution and properties of compressible sediments when used in conjunction with coincident measurements of groundwater levels and other geologic information insar data may be useful for constraining parameter estimates in simulations of aquifer system compaction

estimating spatiotemporal ground deformation with improved persistent scatterer radar interferometry ast synthetic aperture radar interferometry has been applied widely in recent years to ground deformation monitoring although difficulties are often encountered when applying the technology among which the spatial and temporal decorrelation and atmospheric artifacts are the most prominent the persistent scatterer interferometric synthetic aperture radar ps insar technique has overcome some of the difficulties by focusing only on the temporally coherent radar targets in a time series of synthetic aperture radar sar images this paper presents an improved ps insar technique by introducing ps neighborhood networking and empirical mode decomposition emd approaches in the ps insar solution linear deformation rates and topographic errors are estimated based on a least squares method while the nonlinear deformation and atmospheric signals are computed by singular value decomposition and the emd method an area in phoenix az is used as a test site to determine its historical subsidence with 39 c band sar images acquired by european remote sensing 1 and 2 satellites from 1992 to 2000

modeling point velocity and depth statistical distributions in steep tropical and alpine stream reaches 1 statistical hydraulic models predict the frequency distributions of point hydraulic variables relative to their reach averaged values in a stream reach based on its average characteristics e g discharge depth width average particle size the models initially developed in europe have not been tested for steeper streams 4 with coarse grain size we recorded water velocities and depths in 44 reaches of steep streams in tropical islands and the alps during 69 surveys we fitted the observed distributions of velocities and depths using a mixture of two distributions one with low variance and the other with a high variance then we predicted the mixing parameter on the basis of the reach averaged characteristics we compared the observed and predicted frequencies for five classes of velocities including a class of negative velocities and four classes of water depths the predictions of class frequencies have a bias of 5 our statistical model of velocity distribution predicts the frequencies of velocity classes with an explained variance between 33 and 72 for four classes of velocity and null for a class of intermediate velocity the statistical model of depth distributions was less efficient with an explained variance between 25 and 38 for three classes of depth and null for large depths the average froude number the total height of large drops relative to the reach length and the average slope are the main explanatory variables of velocity and depth distributions

relationships between mesoscale morphological units stream hydraulics and chinook salmon oncorhynchus tshawytscha spawning habitat on the lower yuba river california an expert based approach was used to identify 10 morphological unit types within a reach of the gravel bed regulated yuba river california that is heavily utilized by spawning chinook salmon oncorhynchus tshawytscha analysis of these units was carried out using two dimensional hydrodynamic modeling field based geomorphic assessment and detailed spawning surveying differently classified morphological units tended to exhibit discrete hydraulic signatures in most cases the froude number adequately differentiated morphological units but joint depth velocity distributions proved the most effective hydraulic classification approach spawning activity was statistically differentiated at the mesoscale of the morphological unit salmon preferred lateral bar riffle and riffle entrance units these units had moderately high velocity unit median 0 45 m s 1 and low depth unit median 0 6 m but each exhibited a unique joint depth velocity distribution a large proportion of redds 79 were associated with conditions of convective flow acceleration at riffle and riffle entrance locations in addition to reflecting microhabitat requirements of fish it was proposed that the hydraulic segregation of preferred from avoided or tolerated morphological units was linked to the mutual association of specific hydraulic conditions with suitable caliber sediment that promotes the provision and maintenance of spawning habitat

geostatistical analysis of the effects of stage and roughness on reach scale spatial patterns of velocity and turbulence intensity although previous research has documented well organized interactions between the turbulent flow field and an irregular boundary the spatial variability of turbulent flow characteristics at the reach scale remains poorly understood in this paper we present detailed field measurements of three dimensional flow velocities and turbulence intensities in a high gradient cobble bed riffle from three discharges additional data on sediment grain size and bed topography were used to characterize boundary roughness an acoustic doppler velocimeter was used to measure velocities along five cross sections within a 6 in long reach of the north fork cache la poudre river vertical profiles were also measured along the channel thalweg we adopted a spatially explicit stochastic hydraulic approach and focused not on coherent flow structures per se but rather time averaged reach scale variability and spatial pattern scaling velocities and turbulence intensities by the reach averaged friction velocity u accounted for changes in flow depth and enabled comparisons among the three discharges we quantified the effects of stage and roughness by assessing differences among probability distributions of hydraulic quantities and by examining geostatistical metrics of spatial variability we computed semivariograms for streamwise and transverse directions and fit parametric models to summarize the spatial structure of each variable at each discharge cross correlograms were also used to describe the local and lagged effects of boundary roughness on flow characteristics although the probability distributions yielded some insight incorporating spatial information revealed important elements of stage dependent flow structure the development of secondary currents and flow convergence at higher stages were clearly documented in maps and semivariograms in general the spatial structure of the flow field became smoother and more continuous as stage increased and the effects of boundary roughness diminished although roughness elements do influence velocities and turbulence intensities our data suggest that the flow primarily responds to the gross morphology of the channel and that flow depth is the primary control on flow structure the geostatistical framework proved useful and our results indicate that a complete stochastic description must also be explicitly spatial c 2006 elsevier b v all rights reserved

an elusive blind thrust fault beneath metropolitan los angeles seismic reflection profiles petroleum wells and relocated earthquakes reveal the presence of an active blind thrust fault beneath metropolitan los angeles a segment of this fault likely caused the 1987 whittier narrows magnitude 6 0 earthquake mapped sizes of other fault segments suggest that the system is capable of much larger magnitude 6 5 to 7 and more destructive earthquakes

tectonic contraction across los angeles after removal of groundwater pumping effects after the 1987 whittier narrows and 1994 northridge earthquakes revealed that blind thrust faults represent a significant threat to metropolitan los angeles a network of 250 continuously recording global positioning system gps stations was deployed to monitor displacements associated with deep slip on both blind and surface faults here we augment this gps data with interferometric synthetic aperture radar imagery to take into account the deformation associated with groundwater pumping and strike slip faulting after removing these non tectonic signals we are left with 4 4 mm yr 1 of uniaxial contraction across the los angeles basin oriented n 36 degrees e perpendicular to the major strike slip faults in the area this indicates that the contraction is primarily accommodated on thrust faults rather than on the northeast trending strike slip faults we have found that widespread groundwater and oil pumping obscures and in some cases mimics the tectonic signals expected from the blind thrust faults in the 40 km long santa ana basin groundwater withdrawal and re injection produces 12 mm yr 1 of long term subsidence accompanied by an unprecedented seasonal oscillation of 55 mm in the vertical direction and 7 mm horizontally

engineered channel controls limiting spawning habitat rehabilitation success on regulated gravel bed rivers in efforts to rehabilitate regulated rivers for ecological benefits the flow regime has been one of the primary focal points of management strategies however channel engineering can impact channel geometry such that hydraulic and geomorphic responses to flow reregulation do not yield the sought for benefits to illustrate and assess the impacts of structural channel controls and flow reregulation on channel processes and fish habitat quality in multiple life stages a highly detailed digital elevation model was collected and analyzed for a river reach right below a dam using a suite of hydrologic hydraulic geomorphic and ecological methods results showed that despite flow reregulation to produce a scaled down natural hydrograph anthropogenic boundary controls have severely altered geomorphic processes associated with geomorphic self sustainability and instream habitat availability in the case study given the similarity of this stream to many others we concluded that the potential utility of natural flow regime reinstatement in regulated gravel bed rivers is conditional on concomitant channel rehabilitation

the paleoclimatic interpretation of clay minerals in sediments a review abstract the application of paleoclimatic interpretation to clay minerals from continental and marine sediments is reviewed and the advantages of this method are indicated levels relatively rich in chlorite illite palygorskite and quartz are interpreted as corresponding to relatively dry periods while more humid periods lead to more intensive weathering and consequently to the dominance of clay minerals more advanced in the relative stability scale such as kaolinite smectite is taken to indicate a climate with contrasting seasons and a pronounced dry season using this and similar schemes the paleoclimates of areas adjoining the mediterranean basin north sea north atlantic southern arctic equatorial and north west pacific and north phillipine sea are reconstructed clay minerals in sediments particularly marine sediments can be useful indicators of paleoclimatic conditions while they do not produce direct indications of climatic parameters they provide integrated records of overall climatic impact occasionally they may be superior to the more conventional paleoclimatic methods such as pollen or oxygen isotope analysis the limitations imposed on the paleoclimatic interpretation of clay minerals in sediments are discussed on the basis of examples the distinction between authigenic and detrital clay minerals is shown to be problematic particularly with regard to smectite the relationship between climatic parameters and clay mineral formation is complicated by the intervention of extra climatic factors such as topography geomorphology lithology and time post depositional diagenetic changes may not be recognized differentiation during transport due to size sorting or differential flocculation may overlap climate induced differentiation the association of clay mineral assemblages with specific source areas presents difficulties due to dispersal pathways that are affected by type of transport agency i e water ice or wind transport agencies are not constant with time by an interdisciplinary approach with the paleoclimatic information derived from clay minerals being correlated with that obtained from the analysis of microfossils and oxygen isotope data many of these limitations can be overcome

clinoptilolite as a new proxy of enhanced biogenic silica productivity in lower miocene carbonate sediments of the bahamas platform isotopic and thermodynamic evidence abstract massive clinoptilolite authigenesis was observed at about 1105 meters below sea floor mbsf in lower miocene well compacted carbonate periplatform sediments from the great bahama bank ocean drilling program odp leg 166 site 1007 the diagenetic assemblage comprises abundant zeolite crystallized within foraminifer tests and sedimentary matrix as well as mg smectites in carbonate rich deposits the formation of the zeolite requires a supply of silica thus the objective of the study is to determine the origin of the silica supply its diagenetic evolution and consequently the related implications on interpretation of the sedimentary record in terms of local or global paleoceanographic change for lack of evidence for any volcaniclastic input or traces of si enriched deep fluids circulation an in situ biogenic source of silica is validated by isotopic data and chemical modeling for the formation of such secondary minerals in shallow water carbonate sequences geochemical and strontium isotopic data clearly establish the marine signature of the diagenetic zeolite as well as its contemporaneous formation with the carbonate deposition sr model ages of 19 6 23 2 ma the test of saturation for the pore fluids specifies the equilibrium state of the present mineralogical assemblage seawater rock modeling specifies that clinoptilolite precipitates from the dissolution of biogenic silica which reacts with clay minerals the amount of silica opal a involved in the reaction has to be significant enough at least 10 wt to account for the observed content of clinoptilolite occurring at the most zeolite rich level modeling also shows that the observed amount of clinoptilolite 19 reflects an in situ and short term reaction due to the high reactivity of primary biogenic silica opal a until its complete depletion the episodic occurrence of these well lithified zeolite rich levels is consistent with the occurrence of seismic reflectors particularly the p2 seismic sequence boundary located at 1115 mbsf depth and dated as 23 2 ma the age range of most zeolitic sedimentary levels biostratigraphic ages of 21 5 22 ma correlates well with that of the early miocene glaciation mi 1 and mi 1a global events thus the clinoptilolite occurrence in the shallow carbonate platform environment far from volcanogenic supply or in other sensitive marine areas is potentially a significant new proxy for paleoproductivity and oceanic global events such as the miocene events which are usually recognized in deep sea pelagic sediments and high latitude deposits

application of dinsar gps optimization for derivation of fine scale surface motion maps of southern california a method based on random field theory and gibbs markov random fields equivalency within bayesian statistical framework is used to derive 3 d surface motion maps from sparse global positioning system gps measurements and differential interferometric synthetic aperture radar dinsar interferogram in the southern california region the minimization of the gibbs energy function is performed analytically which is possible in the case when neighboring pixels are considered independent the problem is well posed and the solution is unique and stable and not biased by the continuity condition the technique produces a 3 d field containing estimates of surface motion on the spatial scale of the dinsar image over a given time period complete with error estimates significant improvement in the accuracy of the vertical component and moderate improvement in the accuracy of the horizontal components of velocity are achieved in comparison with the gps data alone the method can be expanded to account for other available data sets such as additional interferograms lidar or leveling data in order to achieve even higher accuracy

radar interferometry and its application to changes in the earth s surface geophysical applications of radar interferometry to measure changes in the earth s surface have exploded in the early 1990s this new geodetic technique calculates the interference pattern caused by the difference in phase between two images acquired by a spaceborne synthetic aperture radar at two distinct times the resulting interferogram is a contour map of the change in distance between the ground and the radar instrument these maps provide an unsurpassed spatial sampling density 100 pixels km 2 a competitive precision 1 cm and a useful observation cadence 1 pass month 1 they record movements in the crust perturbations in the atmosphere dielectric modifications in the soil and relief in the topography they are also sensitive to technical effects such as relative variations in the radar s trajectory or variations in its frequency standard we describe how all these phenomena contribute to an interferogram then a practical summary explains the techniques for calculating and manipulating interferograms from various radar instruments including the four satellites currently in orbit ers 1 ers 2 jers 1 and radarsat the next chapter suggests some guidelines for interpreting an interferogram as a geophysical measurement respecting the limits of the technique assessing its uncertainty recognizing artifacts and discriminating different types of signal we then review the geophysical applications published to date most of which study deformation related to earthquakes volcanoes and glaciers using ers 1 data we also show examples of monitoring natural hazards and environmental alterations related to landslides subsidence and agriculture in addition we consider subtler geophysical signals such as postseismic relaxation tidal loading of coastal areas and interseismic strain accumulation we conclude with our perspectives on the future of radar interferometry the objective of the review is for the reader to develop the physical understanding necessary to calculate an interferogram and the geophysical intuition necessary to interpret it

coseismic and postseismic deformation estimation of the 2011 tohoku earthquake in kanto region japan using insar time series analysis and gps abstract we propose a methodology using interferometric synthetic aperture radar insar time series analysis and a single gps station to estimate the coseismic and postseismic crustal deformations in the kanto region japan which has been affected by the 2011 tohoku earthquake the proposed methodology depends on choosing a proper deformation trend s to accurately describe the earthquake deformation signature by studying the deformation time series of a single gps station the modeled deformation trend is subtracted from the unwrapped phase maps to separate the main deformation signature from the imposed errors some deformation components not described by the model s will leak to the residual phase maps which will be subjected to temporal and spatial filtering the final corrected unwrapped phase maps are estimated by restoring the modeled deformation trend to the filtered residual phase maps and finally the deformation time series is estimated using a least squares technique the proposed methodology was designed to retrieve complex and fine surface deformations in areas that have been affected by large dominating deformation signatures and contain at a least single gps station the methodology was tested using envisat asar c band images and validation was carried out using gps stations resulting in a mean rms error of 6 9 mm the estimated deformation time series shows a differential postseismic deformation pattern that can be attributed to an off boso peninsula motion triggered by the 2011 tohoku earthquake

lithologic controls on calcite recrystallization in cenozoic deep sea sediments abstract interpretations of calcite strontium calcium records in terms of ocean history and calcite diagenesis require distinguishing the effects on deep sea calcite sediments of changes in ocean chemistry of different mixes of calcite depositing organisms as sediment contributors through time and space and of the loss of sr during diagenetic calcite recrystallization in this paper sr ca and 18 o values of bulk calcium carbonate sediments are used to estimate the relative extent of calcite recrystallization in samples from four time points core tops 5 6 9 4 and 37 1 ma at eight ocean drilling program sites in the equatorial atlantic ceara rise and equatorial pacific ontong java plateau and two eastern equatorial pacific sites the possibility that site to site differences in calcite sr ca at a given time point originated from temporal variations in ocean chemistry was eliminated by careful age control of samples for each time point with sample ages differing by less than the oceanic residence times of sr and ca the sr ca and 18 o values of 5 6 and 9 4 ma samples from the less carbonate rich eastern equatorial pacific sites and ceara rise site 929 appear to be less diagenetically altered than the sr ca and 18 o values of contemporaneous samples from the more carbonate rich sites it is evident from these data that both sr ca and 18 o in bulk calcite have been diagenetically altered in some samples 5 6 ma and older these data indicate that noncarbonate sedimentary components like clay and biogenic silica have partially suppressed recrystallization at the lower carbonate sites sr ca data from the less altered carbonate poor sites indicate higher oceanic sr ca relative to today at 5 6 and 9 4 ma

a stochastic model of hydraulic variations within stream channels 1 this paper presents a stochastic model of the joint depth and velocity probability distribution in stream channels model input is restricted to simple measures of channel geometry hydraulic distributions are quantified using two independent hydraulic variables each a function of velocity and depth and varying either longitudinally or laterally within a stream channel the stochastic model provides a useful tool for exploring relations between fine scale hydraulic variations and channel geometry one application is modeling fine scale hydraulic habitat conditions in stream channels

a geostatistical framework for quantifying the reach scale spatial structure of river morphology 1 variogram models related metrics and relation to channel form abstract fluvial geomorphology is fundamentally concerned with the association between form and process in rivers examining these interactions in complex natural channels requires a means of quantifying the variability and organization of bed topography this paper introduces a geostatistical framework for characterizing reach scale spatial structure transformation to a channel centered coordinate system allows topographic variations to be resolved into along and across stream components dimensionless variables obtained by scaling distances by the mean channel width and de trended elevations by the mean bankfull depth account for channel size and allow spatial patterns to be compared over time or among sites these patterns are effectively described by the variogram a spatial statistic that expresses dissimilarity as a function of distance fitting a parametric model to the sample variogram provides a rich description of channel form for example multiple nested structures can be combined to account for anisotropy with varying degrees of spatial variability observed over different length scales along and across the channel integral metrics derived from the variogram model yield a more compact summary and variogram maps a useful visualization to guide interpretation of these metrics i used a simple channel builder to isolate the effects of specific aspects of river morphology on the variogram this analysis indicated that geostatistical models were sensitive to changes in the size shape and orientation of channel features but not to a pure translation of the morphology the results also highlighted the importance of considering streamwise and transverse components jointly rather than in isolation

tectonic controls on carbonate sequence formation in an active strike slip setting serranilla basin northern nicaragua rise western caribbean sea abstract the serranilla basin is a flat floored semi circular bathymetric depression 100 100 km 1100 1200 m deep at the western end of the northern nicaragua rise nnr in the caribbean sea it is bound to the north by the cayman trough an area of active sea floor spreading and is part of the northern caribbean plate boundary zone ncpbz single channel high resolution seismic data were calibrated to rock dredges and odp site 1000 to define the geologic evolution and attempt to tie sequence formation within the basin to tectonic developments in this part of the caribbean five seismic sequences were identified within the basin the two lower sequences a and b are interpreted as neritic and shallow periplatform deposits which infill three distinct basins that make up the early to late miocene serranilla basin the three upper sequences c through e are interpreted as periplatform and pelagic deposits interspersed with turbidites and in some areas megabreccias faulting is prevalent in sequences a through c in the central basin and becomes progressively younger toward the south disrupting the seafloor in places and perhaps indicating renewed activity along the pedro fracture zone the timing of sequence boundary formation has been correlated to tectonic activity along the ncpbz and closure of the central american seaway possible mechanisms of sequence boundary formation include tectonic tilting within the basin in conjunction with increased turbidite deposition carbonate platform drowning and subsequent back stepping associated with circulation changes resulting from tectonic gateway closure and megabreccia deposition associated with bank demise although a direct genetic relationship is not proven regional tectonic changes are considered more important than eustatic sea level changes in controlling depositional sequence formation in the serranilla basin

models for the coupled sr sulfate budget in deep sea carbonates a numerical model for the sr and sulfate budgets during deposition of deep sea carbonate sediments was developed and used to fit porewater sr2 and so42 data from dsdp sites 593 590 574 573 572 516 and 289 the sr and sulfate budgets are coupled whenever the porewaters become saturated with respect to celestite srso4 models for the porewater sr and sulfate at sites 593 590 516 and 289 suggest that porewater sr concentrations are controlled by the precipitation of celestite and predict maximum celestite concentrations of the order of 0 02 wt for sediments at sites 593 590 and 289 and trace amounts of celestite at site 516 the actual amount of celestite predicted by the model is not well constrained because it depends on the as yet poorly known value of the equilibrium distribution coefficient for sr between calcite and porewaters the fact that celestite has been found in sediments from sites 590 and 593 is used to derive an upper bound for the sr distribution coefficient that suggests that all laboratory determined values for the sr distribution coefficient between calcite and porewater are too large the occurrence of celestite at sites 593 590 516 and 289 does not significantly change earlier estimates of the rates of solution reprecipitation of calcite and its consequences in terms of shifting the sr content or sr isotopic composition of the bulk sediment from what the sediment incorporated when originally deposited the sulfate data at sites 593 and 590 are best fit by invoking a flow of porewater within the sediments of the order of 75 m ma the sr and sulfate concentrations in porewaters from sites 572 573 and 574 never reach celestite saturation and thus the two budgets are decoupled both the sr and the sulfate data require that all three sites have abundant unaltered seawater flowing in the underlying basement and can only be modeled if seawater concentrations of sr and sulfate are imposed as boundary conditions at both the sediment water interface and the bottom of the section model sulfate profiles for sites 572 573 and 574 confirm prior estimates of the rate of porewater flow at these sites that were made using sr data

an elliptical model for deformation due to groundwater fluctuations historically surface subsidence as a result of subsurface groundwater fluctuations have produced important and at times catastrophic effects whether natural or anthropogenic over the past 30 years numerical and analytical techniques for the modeling of this surface deformation based upon elastic and poroelastic theory have been remarkably successful in predicting the magnitude of that deformation le mouelic and adragna in geophys res lett 29 1853 2002 in this work we have extended the formula for a circular shaped aquifer geertsma in j petroleum tech 25 734 744 1973 to a more realistic elliptical shape we have improved the accuracy of the approximation by making use of the cross terms of the expansion for the elliptic coordinates in terms of the eccentricity e and the mean anomaly angle m widely used in astronomy results of a number of simulations in terms of e and m developed from the transcendental kepler equation are encouraging giving realistic values for the elliptical approximation of the vertical deformation due to groundwater change finally we have applied the algorithm to modeling of groundwater in southern california

phyllosilicates and zeolite assemblages in the carbonate periplatform of the great bahama bank origin and relation to diagenetic processes odp leg 166 sites 1006 and 1007 abstract the western flank of the great bahama bank drilled during odp leg 166 at seven sites represents a prograding carbonate sequence from late oligocene to holocene eberli et al proc odp init reports 166 1997 the signatures of the detrital input and of diagenetic alteration are evident in clay enriched intervals from the most distal sites 1006 and 1007 in the straits of florida mineralogical and chemical investigations xrd tem sem icp ms run on bulk rocks and on the clay fractions enable the origin and evolution of silicate parageneses to be characterized plio pleistocene silt and clay interbeds contain detrital clay assemblages comprising chlorite illite interstratified illite smectite smectite kaolinite and palygorskite the greater smectite input within late pliocene units than in pleistocene oozes may relate either varying source areas or change in paleoclimatic conditions and weathering intensity the clay intervals from miocene upper oligocene wackestone sections are fairly different with prevalent smectite in the fine fraction whose high crystallinity and mg contents that point towards an authigenic origin the lower miocene section below 1104 mbsf at depths where compaction features are well developed is particularly characterized by abundant authigenic na k clinoptilolite filling foraminifer tests the authigenic smectite and clinoptilolite paragenesis is recorded by the chemical trends both of the sediment and the interstitial fluid this diagenetic evolution implies si and mg rich fluids circulating in deeper and older sequences for lack of any local volcaniclastic input the genesis of zeolite and the terms of water rock interaction are discussed the location of the diagenetic front correlates with that of the seismic sequence boundary p2 dated as 23 2 ma this correspondence may allow the chronostratigraphic significance of some specific seismic reflections to be reassessed

geochemistry of eolian dust in pacific pelagic sediments implications for paleoclimatic interpretations geochemical data rees th sc were determined for the operationally defined eolian dust oded fraction 63 m of late quaternary sediment samples n 57 from the north and equatorial pacific ocean paleoclimate studies commonly have assumed that this sediment fraction represents eolian materials from continental source regions this study shows on the basis of geochemical data published mineralogical data and mixing models that the oded fraction actually is a mixture of materials from two endmember sources the continental crust eolian transported weathering products and the oceanic crust primarily volcanogenic material mixing model results show that the average ash content is significant in the oded fraction equatorial pacific 43 north pacific 24 we have used this information to reconsider and refine the results of previous paleoclimate studies in the northwest pacific the flux of the eolian fraction is greater during glacial stages and shows a latitudinal maximum between 35 n and 42 n eolian fluxes are greatest during interglacial periods in the equatorial pacific these results are consistent with previous interpretations in contrast to previous assumptions eolian mass accumulation rates may not be a valid indicator of paleo aridity because they are correlated with grain size furthermore the relative abundance of the two endmembers is correlated with the average grain size of the dust fraction the continental crust component is associated with larger grains this compositional effect should be considered in future studies which commonly utilize grain size as a proxy indicator of paleo wind intensity

satellite interferometry for mapping surface deformation time series in one two and three dimensions a new method illustrated on a slow moving landslide abstract space borne differential interferometric synthetic aperture radar dinsar has been extensively used in the last two decades to measure ground surface deformation providing key information for the characterization and understanding of many natural and anthropogenic processes however conventional dinsar technique measures only one component of the surface deformation i e the satellite s line of sight los causing the interpretation of dinsar measurements to be challenging and potentially narrowing the understanding of the mechanisms and dynamics of the deformation processes at work presently available methods that estimate 3d surface deformation from dinsar generally operate on individual interferograms and therefore do not produce 3d surface deformation time series however the availability of time series is essential for studying surface deformation processes bringing information on e g temporally and spatially variable external forcing conditions and characteristics of future deformation patterns the multidimensional small baseline subset msbas method was already able to produce 2d east and vertical surface deformation time series from multi tracks and multi sensors dinsar data here we propose a novel version of the msbas msbas 3d method that can produce 3d north east and vertical surface deformation time series from ascending and descending dinsar data this new method proposes measuring the surface deformation for processes producing motion parallel to the surface such as landslides and glacier flows while conserving the dinsar accuracy the ability of msbas 3d to capture the full 3d deformation pattern of processes with a surface signature is illustrated for a large slow moving deep seated landslide for which long dinsar and dgnss time series as well as ground truth data are available surface deformation is measured over a four year period using 1d los 2d and 3d msbas methods and the advantages and limitations of each approach are described in this case the novel msbas 3d technique produces superior results that greatly simplify interpretation of the processes at work the msbas 3d software can be downloaded from http insar ca

escape tectonics in the los angeles metropolitan region and implications for seismic risk recent damaging earthquakes in california including the 1971 san fernando1 1983 coalinga2 1987 whittier narrows3 and 1994 northridge4 events have drawn attention to thrust faults as both potentially hazardous seismic sources and as a mechanism for accommodating shortening in many regions of southern california consequently many geological studies5 6 have concluded that thrust faults in southern california pose the greatest seismic hazard and also account for most of the estimated 5 7 mm yr 1 of contraction across the greater los angeles metropolitan area7 8 indicated by global positioning system geodetic measurements9 our study demonstrates however that less than 50 of the geodetically observed contraction is accommodated on the principal thrust systems across the los angeles region we integrate the most recent geological geodetic and seismological data to assess the spatial distribution of strain across the los angeles metropolitan region we then demonstrate that a significant component of seismic moment release and shortening in this region is accommodated by east west crustal escape extrusion along known strike slip and oblique slip faults

provenance of the detrital component of deep sea sediments from the sw pacific ocean based on mineralogy geochemistry and sr isotopic composition abstract clay mineralogy and chemical and strontium isotope compositions have been used to determine the detrital components of deep sea sediments from the sw pacific ocean continental detritus derived mainly from the new zealand landmass is characterised by high illite and chlorite contents and 87 sr 86 sr ratios close to 0 7110 this material eroded from the eastern margin of both islands is transported into deeper water by turbidity currents and hemipelagic processes and is carried northwards by the strong western boundary current as far north as the samoan basin due to the great distance from source and unfavourable prevailing winds the contribution of aeolian dust from the australian deserts to the sediment appears to be relatively small particularly in the northernmost part of the region in the vicinity of the oceanic volcanic islands of tonga samoa and the cook islands volcaniclastic material including heavy minerals pyroxene and magnetite pumice glass shards proximally and smectite clays distally is dispersed into the sediments by turbidity currents and airfall in areas of very low sedimentation distant from landmasses the sediments contain significant amounts of authigenic material rsos characterised by high concentrations of transition metals and rare earth elements strontium isotopes together with trace element compositions have proved particularly useful in determining the relative proportions of the detrital types the contrasting 87 sr 86 sr ratios and sr contents of the various source rocks permit the use of binary mixing relationships whch indicate that sediments less than 35 km from the cook islands contain 80 volcanic detritus and those more than 1200 km away contain up to 20 volcanic detritus

3d displacement maps of the 2009 l aquila earthquake italy by applying the sistem method to gps and dinsar data terra nova 25 79 85 2013 abstract we present an application of the novel sistem approach to obtain the dense 3d ground deformation pattern produced by the april 6 2009 mw 6 3 l aquila earthquake this event characterized by a sw dipping normal fault with thousands of foreshocks and aftershocks located in the depth range 5 15 km is the most destructive to have struck the abruzzo region since the major 1703 seismic sequence the surface deformation revealed by the sistem through the integration of gps with interferometric measurements from the envisat and alos satellites shows a deformed area extending towards se along the aterno valley in agreement with seismological and other geodetic observations we inverted the sistem results using an optimization algorithm based on the genetic algorithm providing an accurate spatial characterization of ground deformation our results improve previous kinematic solutions for the paganica fault and allow identification of additional faults that have contributed to the observed complex ground deformation pattern

cenozoic sedimentation and clay mineralogy in the northern part of the magellan trough central pacific basin abstract assemblages of clay sized minerals in twelve deep sea cores from the northern part of the magellan trough in the central pacific basin clearly show that authigenic smectite together with clinoptilolite formed subsea in situ and predominated throughout palaeogene time clastic clay minerals such as chlorite illite and kaolinite increased at the expense of smectite in sediments deposited since the pliocene most of the authigenic smectites are of the di octahedral iron rich type the most probable origin of the authigenic smectites is formation from precursors such as volcanic glass as part of this process biogenic silica evidently contributed to the formation of smectite and zeolites as clinoptilolite the presence of a tri octahedral saponite and the tem morphology of some smectites on the other hand suggests that not all of the smectite studied was formed subsea in situ but that some had an allogenic origin systematic vertical changes in the assemblage of clay sized minerals suggest that the authigenesis of submarine smectite and clinoptilolite prevailed in conditions of reduced aridity and weak wind activity throughout the palaeogene in the study area however allogenic clay minerals such as chlorite and illite increased since the olduvai event under conditions of severe aridity and strong wind activity caused by global climatic change the west northwest movement of the pacific plate must have partly played a role in deposition of the clastic clay sized minerals from the asian continent by westerlies in the study area the widespread occurrence of cenozoic hiatuses in the study area is attributed to the influence of antarctic bottom water aabw the latter must have influenced non deposition of the clay sized minerals at times during the cenozoic

three dimensional surface motion maps estimated from combined interferometric synthetic aperture radar and gps data 1 we provide a technique to efficiently produce high resolution three dimensional surface motion maps by combining information about the motion of the earth s surface from interferometric observations of synthetic aperture radar images and repeated global positioning system gps geodetic measurements unwrapped interferograms showing pixel wise change in range from ground to satellite and sparse values of threedimensional movements are required as input the problem of finding the full threedimensional motion field is separated into two two dimensional problems initially the vertical component of the deformation field and its horizontal component in the look direction of the satellite are found later the look direction component is resolved into north and east components initial values for the motion fields are assigned to each pixel of interferograms from interpolation of available gps observations these values are then updated and optimized by comparison with the interferograms and the gps observations an additional constraint is an assumption of a smoothly varying motion field markov random field based regularization and simulated annealing algorithm are used for the optimization the technique is applied to create surface motion maps for the reykjanes peninsula sw iceland index terms 0933 exploration geophysics remote sensing 0910 exploration geophysics data processing 1206 geodesy and gravity crustal movements interplate 8155 8150 tectonophysics evolution of the earth plate boundary general 3040 8155 tectonophysics evolution of the earth plate motions general keywords remote sensing motion maps deformation data fusion interferometry gps

satellite interferometric observations of displacements associated with seasonal groundwater in the los angeles basin 1 the newport inglewood fault zone nifz displays interferometric synthetic aperture radar sar phase features along most of its length having amplitudes of up to 60 mm however interpretation in terms of right lateral shallow slip along the fault fails to match the range of geologic estimates of slip recently bawden et al 2001 proposed that these phase features as well as a broader deformation pattern in the los angeles basin are due to vertical motion related to annual variations in the elevation of the water table we confirm this hypothesis through the analysis of a longer span of data consisting of 26 sar images collected by the ers 1 and ers 2 spacecraft between june 1992 and june 2000 moreover we use continuous gps measurements from 1995 to the present to establish the amplitude and phase of the vertical deformation the los angeles basin becomes most inflated one quarter of the way through the year which is consistent with water table measurements as well as with the end of the rainy season when the aquifer should be at a maximum the spatial pattern of the amplitude of the annual signal derived from continuous gps measurements is consistent with the shape of the interferometric fringes gps sites both near the nifz and in a 20 by 40 km zone within the basin also show significant n s annual variations that may be related to the differential expansion across the fault since these horizontal signals have peak to trough amplitudes of 6 mm they mask the smaller tectonic signals and need to be taken into account when interpreting gps time series of site position moreover since the groundwater signal appears to have a long term vertical trend which varies in sign depending on location it will be difficult to distinguish interseismic tectonic slip along the nifz and within the affected areas in the basin

a plate tectonic model for the mesozoic and early cenozoic history of the caribbean plate abstract we present a model in which the caribbean plate is an intra american feature formed along the caribbean spreading center as opposed to the current model that considers the caribbean plate as a far travelled crustal segment that formed in the pacific region paleomagnetic data which cover an age range from jurassic through paleocene indicate the ophiolite complexes in costa rica and panama formed in an equatorial position the ophiolites did not fundamentally change their position relative to south america since their origin basaltic rocks of the lower part of the ophiolites are of mid ocean ridge type suggesting formation at a spreading center they are interpreted to have formed as part of the proto caribbean crust at a spreading axis in an intra american position during jurassic and early cretaceous times the upper part of the ophiolites is mainly built up by island arc and intraplate basalts the island arc basalts evolved at the central american landbridge which started in the middle cretaceous the intraplate basalts are related to the caribbean plateau basalt which thickened and stiffened the caribbean crust in middle cretaceous to probably campanian times changes in relative plate motions along the middle american convergent plate margin are reflected by orientations and time sequences of paleostress tensors calculated from fault slip data in southern mexico and costa rica kinematic indicators from mylonite zones display sinistral movement along secondary shear zones within the southern mexican crustal complexes and along the northern boundary of the chortis block in the motagua polochic fault system this reflects the eastward drift of the chortis block since the beginning of the cenozoic at this time the chortis block became part of the caribbean plate which moved more than 1000 km towards the east relative to the north and south american plates during the cenozoic

derivation of 3 d coseismic surface displacement fields for the 2011 mw 9 0 tohoku oki earthquake from insar and gps measurements

clay mineral distribution in surface sediments of the south atlantic sources transport and relation to oceanography abstract surface samples mostly from abyssal sediments of the south atlantic from parts of the equatorial atlantic and of the antarctic ocean were investigated for clay content and clay mineral composition maps of relative clay mineral content were compiled which improve previous maps by showing more details especially at high latitudes large scale relations regarding the origin and transport paths of detrital clay are revealed high smectite concentrations are observed in abyssal regions primarily derived from southernmost south america and from minor sources in southwest africa near submarine volcanoes of the antarctic ocean south sandwich bouvet island smectite contents exhibit distinct maxima which is ascribed to the weathering of altered basalts and volcanic glasses the illite distribution can be subdivided into five major zones including two maxima revealing both south african and antarctic sources a particularly high amount of mg and fe rich illites are observed close to east antarctica they are derived from biotite bearing crystalline rocks and transported to the west by the east antarctic coastal current chiorite and well crystallized dioctaedral illite are typical minerals enriched within the subantarctic and polarfrontal zone but of minor importance off east antarctica kaolinite dominates the clay mineral assemblage at low latitudes where the continental source rocks west africa brazil are mainly affected by intensive chemical weathering surprisingly a slight increase of kaolinite is observed in the enderby basin and near the filchner ronne ice shelf the investigated area can be subdivided into ten large scale clay facies zones with characteristic possible source regions and transport paths clay mineral assemblages of the largest part of the south atlantic especially of the western basins are dominated by chlorite and illite derived from the antarctic peninsula and southernmost south america and supported by advection within the circumantarctic deep water flow in contrast the east antarctic provinces are relatively small assemblages of the eastern basins north of 30 s are strongly influenced by african sources controlled by weathering regimes on land and by a complex interaction of wind river and deep ocean transport the strong gradient in clay mineral composition at the brazilian slope indicate a relatively low contribution of tropically derived assemblages to the western basins

mechanisms of mg phyllosilicate formation in a hydrothermal system at a sedimented ridge middle valley juan de fuca we present results of a detailed mineralogical and geochemical study of the progressive hydrothermal alteration of clastic sediments recovered at odp site 858 in an area of active hydrothermal venting at the sedimented axial rift valley of middle valley northern juan de fuca ridge these results allow a characterization of newly formed phyllosilicates and provide constraints on the mechanisms of clay formation and controls of mineral reactions on the chemical and isotopic composition of hydrothermal fluids hydrothermal alteration at site 858 is characterized by a progressive change in phyllosilicate assemblages with depth in the immediate vent area at hole 858b detrital layers are intercalated with pure hydrothermal precipitates at the top of the section with a predominance of hydrothermal phases at depth sequentially downhole in hole 858b the clay fraction of the pure hydrothermal layers changes from smectite to corrensite to swelling chlorite and finally to chlorite in three pure hydrothermal layers in the deepest part of hole 858b the clay minerals coexist with neoformed quartz neoformed and detrital components are clearly distinguished on the basis of morphology as seen by sem and tem and by their chemical and stable isotope compositions corrensite is characterized by a 24 a stacking sequence and high si and mg contents with fe fe mg ratio of 0 08 we propose that corrensite is a unique possibly metastable mineralogical phase and was precipitated directly from seawater dominated hydrothermal fluids hydrothermal chlorite in hole 858b has a stacking sequence of 14 a with fe fe mg ratios of 0 35 the chemistry and structure of swelling chlorite suggest that it is a corrensite chlorite mixed layer phase the mineralogical zonation in hole 858b is accompanied by a systematic decrease in 18o reflecting both the high thermal gradients that prevail at site 858 and extensive sediment fluid interaction precipitation of the mg phyllosilicates in the vent region directly controls the chemical and isotopic compositions of the pore fluids this is particularly evident by decreases in mg and enrichments in deuterium and salinity in the pore fluids at depths at which corrensite and chlorite are formed structural formulae calculated from tem edx analyses were used to construct clay h2o oxygen isotope fractionation curves based on oxygen bond models our results suggest isotopic disequilibrium conditions for corrensite quartz and swelling chlorite quartz precipitation but yield an equilibrium temperature of 300 c 30 for chlorite quartz at 32 m below the surface this estimate is consistent with independent estimates and indicates steep thermal gradients of 10 11 m in the vent region

chemistry of surface sediment along a north south transect across the equator in the central indian basin an assessment of biogenic and detrital influences on elemental burial on the seafloor nineteen surface sediment samples collected along a north south transect across the equator in the central indian basin cib were analysed for their major minor and rare earth element ree composition in absence of the element flux data we demonstrate here the association of various elements and their preferential sinks using inter elemental associations in sediment exhibiting latitudinal dissimilarity biogenic sedimentation north of the equator 1 to 4 n latitudes is dominated by carbonate ooze whereas south of the equator 4 to 14 s latitudes is dominated by siliceous ooze carbonate ooze deposition 60 caco3 above 4400 m and its drastic reduction to 80 of their respective total content in all the three sediment zones these observations suggest a close link between ba and a mn oxide phase on the other hand nearly overlapping latitudinal trends of alxs with carbonate in areas north of the equator and opal south of the equator strong positive correlation of alxs with opal r 0 8 similar ratios between carbonate free opal and alxs 16 in both biogenic sediments suggest a close link between productivity and alxs the alxs proportion in both biogenic sediment types is around 28 of the total al suggesting nearly the same level of primary productivity along the transect 4 n to 14 s which supports the estimates of berger berger w h 1989 global maps of the ocean productivity in w h berger v s smetacek g wefer eds productivity of the ocean present and past dahlem workshop reports wiley chichester pp 429 455 and kabanova kabanova j g 1968 primary production of the northern part of the indian ocean oceanology 8 214 255 i e 70 g cm 2 y 1 the rees exhibit mutual coherence in the sediment r 0 7 however they display an increasing affinity towards mn r increases from 0 6 to 0 8 and decreasing affinity towards ti r decreases from 0 8 to 0 3 with increasing atomic number such a subtle but systematic variation within ree group suggests preferential burial of heavy ree by mn oxide phase and light ree by detrital phase

hydraulic geometry of stream reaches abstract variation in river hydraulic geometry throughout stream networks is central to the problems of catchment management because of its influence on flow and sediment routing physical habitats and channel floodplain interactions in its simplest form at a station hydraulic geometry is described by power functions relating the surface width water depth and mean velocity at a channel cross section to discharge this paper extends hydraulic geometry analysis to represent the mean and variation of hydraulic characteristics along a river reach as power functions of discharge using 54 surveys of 17 river reaches mostly in south east australia it is shown that five reach hydraulic variables are sufficient to characterise the gross hydraulic conditions along a river reach the means and coefficients of variation of surface width and hydraulic depth plus the coefficient of variation of cross sectional velocity exponents for the mean width and mean depth hydraulic geometry relations are sensitive to measurement and cross section location and may best be treated as constant for regional studies coefficients for the mean width and mean depth hydraulic geometry relations are correlated positively with mean discharge and negatively with reach gradient respectively further analysis of variations in reach hydraulic geometry parameters particularly the power function coefficients in relation to river type flow parameters sediment load bank material and bank vegetation is warranted reach hydraulic geometry relations show considerable potential for improving analyses of fluvial processes and physical habitats across catchments

linking the oxygen isotope record of late neogene eustasy to sequence stratigraphic patterns along the bahamas margin results from a paleoceanographic study of odp leg 166 site 1006 sediments abstract during odp leg 166 the recovery of cores from a transect of drill sites across the bahamas margin from marginal to deep basin environments was an essential requirement for the study of the response of the sedimentary systems to sea level changes a detailed biostratigraphy based on planktonic foraminifera was performed on odp hole 1006a for an accurate stratigraphic control the investigated late middle miocene early pliocene sequence spans the interval from about 12 5 ma biozone n12 to approximately 4 5 ma biozone n19 several bioevents calibrated with the time scale of berggren et al 1995a b were identified the odp site 1006 benthic oxygen isotope stratigraphy can be correlated to the corresponding deep water benthic oxygen isotope curve from odp site 846 in the eastern equatorial pacific shackleton et al 1995 proc odp sci res 138 337 356 which was orbitally tuned for the entire pliocene into the latest miocene at 6 0 ma the approximate stratigraphic match of the isotopic signals from both records between 4 5 and 6 0 ma implies that the paleoceanographic signal from the bahamas is not simply a record of regional variations but indeed represents glacio eustatic fluctuations the odp site 1006 oxygen and carbon isotope record based on benthic and planktonic foraminifera was used to define paleoceanographic changes on the margin which could be tied to lithostratigraphic events on the bahamas carbonate platform using seismic sequence stratigraphy the oxygen isotope values show a general cooling trend from the middle to late miocene which was interrupted by a significant trend towards warmer sea surface temperatures sst and associated sea level rise with decreased ice volume during the latest miocene this trend reached a maximum coincident with the miocene pliocene boundary an abrupt cooling in the early pliocene then followed the warming which continued into the earliest pliocene the late miocene paleoceanographic evolution along the bahamas margin can be observed in the odp site 1006 13c values which support other evidence for the beginning of the closure of the panama gateway at 8 ma followed by a reduced intermediate water supply of water from the pacific into the caribbean at about 5 ma a general correlation of lower sedimentation rates with the major seismic sequence boundaries ssbs was observed additionally the ssbs are associated with transitions towards more positive oxygen isotope excursions this observed correspondence implies that the presence of a ssb representing a density impedance contrast in the sedimentary sequence may reflect changes in the character of the deposited sediment during highstands versus those during lowstands however not all of the recorded oxygen isotope excursions correspond to ssbs the absence of a ssb in association with an oxygen isotope excursion indicates that not all oxygen isotope sea level events impact the carbonate margin to the same extent or maybe even represent equivalent sea level fluctuations thus it can be tentatively concluded that ssbs produced on carbonate margins do record sea level fluctuations but not every sea level fluctuation is represented by a ssb in the sequence stratigraphic record

multiphase silurian bentonites in the baltic palaeobasin abstract the mineral composition of altered volcanic ash beds bentonites deposited in marine environments is typically characterized by smectite or illite smectite type clay minerals silurian bentonites from an unmetamorphosed normal marine sedimentary sequence in the eastern baltic palaeobasin however show a complex and varied mineral composition with illite smectite k feldspar and kaolinite as the dominant authigenic phases the whole rock xrd study of 52 bentonite beds from two drill cores ruhnu and ohesaare southwestern estonia reveals a range of compositions varying between different beds as well as laterally within a single bed the observed variations are found to reflect the bentonite development and diversification during initial stages of volcanic ash transformation and diagenesis that was probably overprinted by a later k metasomatic event

habitat effects on depth and velocity frequency distributions implications for modeling hydraulic variation and fish habitat suitability in streams abstract describing the velocity and depth attributes of stream channels is a basic goal of theoretical and applied hydrology and is also essential for modeling biological processes in streams we applied frequency distributions gamma probability functions fit to point velocity and depth data to evaluate their ability to describe variation in hydraulic conditions at the channel unit scale among contrasting habitat types pools glides riffles and runs at different flows in a small trout stream velocity and depth distributions differed systematically between habitat types with linear regression explaining 65 and 72 respectively of variation in gamma distribution parameters related to skewness and kurtosis however distribution parameters were not significantly related to discharge relative depth explained 68 79 of the variation in slopes of at a station hydraulic geometry relationships between different habitat types differentiation of habitat types in a velocity depth phase space was reduced at high flows and differences in hydraulic geometry exponents were consistent with flow convergence at high discharge modeling variance in velocity and depth using locally derived gamma distributions in conjunction with simple hydraulic geometry provided accurate estimates of reach average habitat suitability for trout frequency distributions derived from a set of new zealand streams provided much poorer estimates of habitat suitability frequency distributions are useful as an heuristic tool for understanding and modeling drivers of spatial variation in hydraulics and provide a simple method to model hydraulic conditions in streams however general transferability of frequency distributions between streams would be improved by validating and refining existing relationships between distribution parameters and easily measured stream characteristics like habitat type channel size gradient and substrate caliber

radarsat 2 d insar for ground displacement in permafrost terrain validation from iqaluit airport baffin island canada abstract the use of differential interferometric synthetic aperture radar d insar is rapidly gaining acceptance as a source of ground displacement information for permafrost regions the accuracy of the information however is still not well established this paper uses a stack of radarsat 2 d insar data to map seasonal ground displacement at the iqaluit airport baffin island canada the accuracy and information content of the d insar products are evaluated with a variety of ground truth data the d insar derived seasonal ground displacement patterns align well with surficial geology units and reflect the thaw settlement characteristics of the sediments they also identify localised displacement patterns in the vicinity of features such as ice wedges and frost cracks comparisons with ground settlement measurements from in situ thaw tubes indicate sub centimetre agreement in dry areas in low lying wet areas however subject to saturation and flooding the d insar stack significantly underestimates the true settlement detecting only 3 7 cm of the 8 5 cm thaw tube measurement the combination of high phase gradients and poor coherence over intermittently flooded surfaces makes it challenging to preserve reliable phase measurements in these areas information from electromagnetic surveys shows that some surface displacement is related to sub surface conditions

southern california permanent gps geodetic array error analysis of daily position estimates and site velocities we analyze time series of daily positions estimated from data collected by 10 continuously monitoring global positioning system gps sites in southern california during the 19 month period between the june 28 1992 mw 7 3 landers and january 17 1994 mw 6 7 northridge earthquakes each time series exhibits a linear tectonic signal and significant colored noise spectral power at frequencies in the range 5 yr 1 to 0 5 d 1 is dominated by white noise or possibly fractal white noise and is several orders of magnitude higher than what would be expected from random walk noise in this short period range attributed by others to geodetic monument motions estimating a single slope for the time series power spectra suggests fractal white noise processes with spectral indices of about 0 4 site velocity uncertainties assuming this fractal white noise model are 2 4 times larger than uncertainties obtained assuming a purely white noise model a combination white noise plus flicker noise spectral index of 1 model also fits the data and suggests that the velocity uncertainties should be 3 6 times larger than for the white noise model we cannot adequately distinguish between these two noise models nor can we rule out the possibility of a random walk signal at the lowest frequencies these questions await the analysis of longer time series in any case reducing the magnitude of low frequency colored noise is critical and appears to be best accomplished by building sites with deeply anchored and braced monuments otherwise rate uncertainties estimated from continuous gps measurements may not be improved significantly compared to those estimated from infrequent campaign mode measurements

analysis of the evolution of ground movements in a low densely urban area by means of dinsar technique abstract this paper presents an application example of the use of the differential interferometry synthetic aperture radar technique dinsar for monitoring ground movements in a geologically complex area around the village of suria ebro basin catalonia ne spain associated to underground mining activities and to the presence of a salt dome the analysis has been mostly performed in a rural environment affected by ground movements with different patterns magnitudes and causes a total of fifty sar images recorded between 1995 and 2007 were processed to generate the interferograms in order to study the non linear trends or changes of the ground surface behavior the dinsar technique was applied in two sets of images the interferometric results in the form of vertical displacement rate maps were checked against conventional surveying and gps measurements the results present a significant discrepancy in some location due to the wrapping of the phase when both fast and significant deformations occur in order to avoid the latter effect and improve the accuracy of the results all sar images were reprocessed using topographic leveling and gps data of different monitored points to support the dinsar interpretation a detailed geological reconnaissance of the study area was carried out as well as an inventory of ground movement indicators four different patterns of ground movement have been identified active shifting subsidence associated to the progression of the mining exploitation fronts residual subsidence on abandoned galleries with a decreasing rate of closure uplifting due to the intrusion of the salt dome and sudden ground collapses sinkholes caused by the dissolution of soluble materials laying close to the ground surface

chemical transport to the seafloor of the equatorial pacific ocean across a latitudinal transect at 135 w tracking sedimentary major trace and rare earth element fluxes at the equator and the intertropical convergence zone we have analyzed the major trace and rare earth element composition of surface sediments collected from a transect across the equator at 135 w longitude in the pacific ocean comparing the behavior of this suite of elements to the caco3 opal and corg fluxes which record sharp maxima at the equator previously documented at the same sampling stations enables us to assess the relative significance of the various pathways by which trace elements are transported to the equatorial pacific seafloor the 1 1 high biogenic source at the equator associated with equatorial divergence of surface water and upwelling of nutrient rich water and 2 2 high aluminosilicate flux at 4 n associated with increased terrigenous input from elevated rainfall at the intertropical convergence zone itcz of the tradewinds are the two most important fluxes with which elemental transport is affiliated the biogenic flux at the equator transports ca and sr structurally bound to carbonate tests and mn primarily as an adsorbed component trace elements such as cr as pb and the rees are also influenced by the biogenic flux at the equator although this affiliation is not regionally dominant normative calculations suggest that extremely large fluxes of ba and p at the equator are carried by only small proportions of barite and apatite phases the high terrigenous flux at the itcz has a profound effect on chemical transport to the seafloor with elemental fluxes increasing tremendously and in parallel with ti normative calculations however indicate that these fluxes are far in excess of what can be supplied by lattice bound terrigenous phases the accumulation of ba is greater than is affiliated with biogenic transport at the equator while the p flux at the itcz is only 10 less than at the equator this challenges the common view that ba and p are essentially exclusively associated with biogenic fluxes many other elements including mn pb as and rees also record greater accumulation beneath the itcz than at the equator thus adsorptive scavenging by terrigenous paniculate matter or phases intimately associated with them appears to be an extremely important process regulating elemental transport to the equatorial pacific seafloor these findings emphasize the role of vertical transport to the sediment and provide additional constraints on the paleochemical use of trace elements to track biogenic and terrigenous fluxes

estimation of 3 d surface displacement based on insar and deformation modeling a new approach is presented for mapping 3 d surface displacement caused by subsurface fluid volumetric change based on 1 d interferometric synthetic aperture radar insar line of sight measurements and surface deformation modeling the relationship between surface deformation and source fluid volumetric change is modeled according to elastic half space theory a distinctive advantage of the proposed approach is that it effectively extends the capability of the sun synchronous orbit side looking synthetic aperture radar that has been essentially only able to measure 1 d displacements accurately or at most 2 d displacements when insar measurements from more than one orbit or platform are combined experimental studies are carried out with both simulated and real data sets to test the performance of the method the results have demonstrated that the approach works very well