controlling mechanisms for molybdenum isotope fractionation in porphyry deposits the qulong example molybdenite bearing porphyry deposits are the predominant supplier of molybdenum to industrialized society and one of the main hosts of mo in the upper continental crust the mo isotope compositions 98 95mo normalized to nist3134 equals 0 of molybdenite show considerable variation 1 62 to 2 27 but the factors controlling this variability remain poorly constrained this information is critical for underpinning genetic models of porphyry deposits understanding elemental cycling and utilizing the 98 95mo of marine sediments as a paleoredox proxy using the well characterized qulong porphyry cu mo deposit tibet as an example here we discuss how rapid cooling facilitated by mixing hot magmatic fluid with cold meteoric water can be a controlling factor on efficient mineralization and then tackle how fluid evolution regulates molybdenum isotope fractionation molybdenites which preferentially partition isotopically light mo rayleigh fractionation precipitated from a single fluid will develop a heavier 98 95mo composition over time and this also creates heterogeneous 98 95mo between molybdenite grains whereas a fluid undergoing multiple episodes of intensive boiling will gradually lose its isotopically heavy mo to the vapor phase molybdenites crystallizing successively from the residual liquid will then have lighter 98 95mo over time however when mineralization efficiency becomes too low a negligible variation in 98 95mo of molybdenite is observed given that the mineralization efficiency i e the amount of mo crystallized as molybdenite from the fluid rarely reaches 100 and molybdenite favors isotopically light mo the presence of a residual fluid with isotopically heavy mo is inevitable this residual fluid may then become trapped in alteration halos hence 98 95mo has the potential to aid in locating the mineralization center e g lighter 98 95mo toward the orebody the residual fluid may also feed surface hydrological systems and eventually impact mo cycling our study highlights that understanding the controls of isotope fractionation is critical to bridge the gap between ore formation and elemental cycling and that other transition metals e g cu fe and zn may follow similar trajectories

combination of precise leveling and insar data to constrain source parameters of the mw 6 5 26 december 2003 bam earthquake we used new precise leveling data acquired 40 days after the bam earthquake in combination with radar interferometry observations from both ascending and descending orbits to investigate static deformation associated with the 2003 bam earthquake we invert this geodetic data set to gain insight into the fault geometry and slip distribution of the rupture the best fitting dislocation model is a steeply east dipping right lateral strike slip fault that has a size of 11 by 8 km and strikes n2 w we find that such smooth geometry fits available geodetic data better than previously proposed models for this earthquake our distributed slip model indicates a maximum strike slip of 3 m occurring about 3 to 5 km deep the slip magnitude and depth of faulting taper to the north where the fault approaches the bam city inclusion of crustal layering increases the amount of maximum slip inferred at depth by about 4

assessments of serious anthropogenic land subsidence in yunlin county of central taiwan from 1996 to 1999 by persistent scatterers insar article i nfo anthropogenic ground subsidence due to massive pumping of groundwater is one of the severe environmen tal hazards in taiwan the yunlin county located in the southwestern coastal region of taiwan is one of the most counties with serious land subsidence because of the agricultural needs in certain areas of the region the subsidence rate reaches as much as 14 3 cm yr the severe land subsidence gives rise to the risk of flood hazard and damage of infrastructures in this area we represented a persistent scatterers insar psinsar results deduced from 1996 to 1999 time span for monitoring of land subsidence in this area the psinsar results show that baojhou tuku and yuanchang townships reveal a maximum subsidence rate of about 7 8 cm yr along the los and lunbei township located on the northern yunlin reveals a subsidence rate of 3 5 cm yr which is quite coincident with the precise leveling result this result has proven that the effective reduction of labor and cost could be achieved by using this technique on monitoring land subsidence in

interseismic strain accumulation and the earthquake potential on the southern san andreas fault system the southern section of the san andreas fault is the only part of the fault that hasn t ruptured in historic times for this reason it is believed to pose the largest seismic risk in california although whether tectonic stress is actually accumulating there is a topic of heated debate using data from radar interferometry satellites yuri fialko has produced a detailed map of surface deformation in the area that shows that elastic stress is accumulating at a fairly high rate during the past 300 years a displacement of 6 to 9 metres has built up this suggests that the southern san andreas fault is nearing the end of the interseismic phase of the earthquake cycle and that increased seismic activity of some kind can be expected the san andreas fault in california is a mature continental transform fault that accommodates a significant fraction of motion between the north american and pacific plates the two most recent great earthquakes on this fault ruptured its northern and central sections in 1906 and 1857 respectively the southern section of the fault however has not produced a great earthquake in historic times for at least 250 years assuming the average slip rate of a few centimetres per year typical of the rest of the san andreas fault the minimum amount of slip deficit accrued on the southern section is of the order of 7 10 metres comparable to the maximum co seismic offset ever documented on the fault1 2 here i present high resolution measurements of interseismic deformation across the southern san andreas fault system using a well populated catalogue of space borne synthetic aperture radar data the data reveal a nearly equal partitioning of deformation between the southern san andreas and san jacinto faults with a pronounced asymmetry in strain accumulation with respect to the geologically mapped fault traces the observed strain rates confirm that the southern section of the san andreas fault may be approaching the end of the interseismic phase of the earthquake cycle

tectonic evolution of the la gonzalez pull apart basin in the merida andes combination of geological data and satellite radar interferometry insar the 500 km long bocono strike slip fault runs as a major active fault along the backbone of the merida andes fold and thrust belt the recent right lateral motion on the fault led to formation of numerous structures such as pull apart basins which have formed in releasing bends and or right step offsets along the fault strands the la gonzalez pull apart is the biggest basin generated as an extensional strike slip duplex in the central part of the fault this duplex is made up of two strands of the bocono fault as master first order faults while normal right lateral faults which formed during evolution of the basin are second order faults the extension of the basin is associated with seismic activities and surface offsets along the bocono fault insar investigations over a 31 month period also support active deformation within the basin these data indicate that the la gonzalez basin is continuously being extended as a result of motion along the bocono fault and formation of subsequent normal faults in addition the basin is being transversely shortened in nw se direction due to regional shortening across the merida andes range followed by convergence between the maracaibo microplate and the guyana shield

ground subsidence in semarang indonesia investigated by alos palsar satellite sar interferometry abstract the focus of this study is investigation of land subsidence in semarang city indonesia with the use of interferometry synthetic aperture radar insar of alos palsar satellite we processed 22 ascending sar images during january 2007 to january 2009 plus two descending sar images acquired on 6 june 2006 and 17 june 2007 the time series analysis of interferometry was performed by using 12 pairs of interferogram relative to 21 january 2007 and 8 pairs of interferogram relative 24 january 2008 the topographic phase contribution was removed using the 3 arcsec 90 m shuttle radar topography mission srtm digital elevation model dem we performed precision baseline estimation to vanish the fringes from baseline effect between master and slave data in order to investigate the contribution of horizontal movement in our analysis we constructed two interferograms of ascending orbit and descending orbit the time series results exhibited that the area is subsiding continuously without a significant seasonal effect during january 2007 to january 2009 the land subsidence observed from insar data is approximately up to 8 cm year three cross sections on image displacement show the extreme land subsidence occurred especially along the coastal area and lowland area where this area is considered as industrial with high density settlements consuming a lot of groundwater and land is changed from agriculture and cultivation purposes to industrial estates and house our result also shows a consistency with historical pattern of subsidence measured by leveling data the results highlight the potential use of insar measurements to provide better constraints for land subsidence in semarang city indonesia

mo isotope fractionation during hydrothermal evolution of porphyry cu systems we present mo isotope compositions of molybdenite types from three successive stages of ore deposition in several porphyry copper deposits of the kerman region iran the data provide new insights into controlling processes on mo isotope fractionation during the hydrothermal evolution of porphyry systems the mo isotope compositions of 27 molybdenite samples show wide variations in 97mo ranging from 0 37 to 0 92 the data reveal that molybdenites in the early and transitional stages of mineralization preferentially 2h polytypes 97mo mean 0 35 have higher 97mo values than late stage mainly 3r polytypes 97mo mean 0 02 molybdenites this trend suggests that fractionation of mo isotopes occurred in high temperature stages of mineralization and that hydrothermal systems generally evolve towards precipitation of molybdenite with lower 97mo values taking into account the genetic models proposed for porphyry cu deposits along with the temperature dependent fractionation of mo isotope ratios it is proposed that large variations of mo isotopes in the early and the transitional stages of ore deposition could be controlled by the separation of the immiscible ore forming fluid phases with different density ph and o2 properties i e brine and vapor the fractionation of mo isotopes during fluid boiling and rayleigh distillation processes likely dominates the mo isotope budget of the remaining ore forming fluids for the late stage of mineralization the lower 97mo values in the late stage of mineralization can be explained by depletion of the late ore forming hydrothermal solutions in 97mo as these fluids have moved to considerable distance from the source finally the relationship observed between mos2 polytypes 2h and 3r and their mo isotopic compositions can be explained by the molecular vibration theory in which heavier isotopes are preferentially partitioned into denser primary 2h mos2 crystals

seismogenic stress field beneath the tatun volcano group northern taiwan article i nfo the tatun volcano group tvg represents the main volcanic center in northern taiwan and based on various observations it is considered a potentially active volcano tvg has been monitored since 2003 by a seismic network that consists of eight stations equipped with three component short period and broadband seismometers in this study we use waveform data of high frequency earthquakes in order to investigate the stress field orientation beneath the tvg area the focal mechanisms of 35 selected events have been derived using p wave polarities and amplitude ratios assuming a double couple source these fault plane solutions and various subsamples derived from them were subsequently inverted for the best fitting stress tensor using a linear inversion method the results show stress homogeneity beneath tvg for depths larger than 3 km while the stress tensor is characterized by a subvertical 1 and a subhorizontal nw se trending 3 axis consistent with the regional stress field in northern taiwan on the other hand chihsinshan which is an area of vigorous hydrothermal activity exhibits a localized stress field with horizontal nw se trending 3 axis and ne sw trending horizontal 1 such an axes orientation is likely to be causing opening of microcracks and thus favour the ascent and circulation of fluids in the upper crust shear wave splitting measurements seem to confirm these results showing fast polarization directions along nne ne subparallel to the main fracture system in tvg shear wave anisotropy averages about 2 9 and is probably caused by an anisotropic volume of fluid saturated cracks within the upper 2 5 km of the crust

itrf2000 a new release of the international terrestrial reference frame for earth science applications 1 for the first time in the history of the international terrestrial reference frame the itrf2000 combines unconstrained space geodesy solutions that are free from any tectonic plate motion model minimum constraints are applied to these solutions solely in order to define the underlying terrestrial reference frame trf the itrf2000 origin is defined by the earth center of mass sensed by satellite laser ranging slr and its scale by slr and very long baseline interferometry its orientation is aligned to the itrf97 at epoch 1997 0 and its orientation time evolution follows conventionally that of the no net rotation nnr nuvel 1a model the itrf2000 orientation and its rate are implemented using a consistent geodetic method anchored over a selection of itrf sites of high geodetic quality ensuring a datum definition at the 1 mm level this new frame is the most extensive and accurate one ever developed containing about 800 stations located at about 500 sites with better distribution over the globe compared to past itrf versions but still with more site concentration in western europe and north america about 50 of station positions are determined to better than 1 cm and about 100 sites have their velocity estimated to at or better than 1 mm yr level the itrf2000 velocity field was used to estimate relative rotation poles for six major tectonic plates that are independent of the trf orientation rate a comparison to relative rotation poles of the nuvel 1a plate motion model shows vector differences ranging between 0 03 and 0 08 m y equivalent to approximately 1 7 mm yr over the earth s surface itrf2000 angular velocities for four plates relative to the pacific plate appear to be faster than those predicted by the nuvel 1a model the two most populated plates in terms of space geodetic sites north america and eurasia exhibit a relative euler rotation pole of about 0 056 0 005 m y faster than the pole predicted by nuvel 1a and located about 10 n 7 e more to the northwest compared to that model

the remarkable re os chronometer in molybdenite how and why it works the re os rhenium osmium chronometer applied to molybdenite mos2 is now demonstrated to be remarkably robust surviving intense deformation and high grade thermal metamorphism successful dating of molybdenite is dependent on proper preparation of the mineral separate and analysis of a critical quantity of molybdenite unique to each sample such that recognized spatial decoupling of 187re parent and 187os daughter within individual molybdenite crystals is overcome highly precise accurate and reproducible age results are derived through isotope dilution and negative thermal ion mass spectrometry id ntims spatial decoupling of parent daughter precludes use of the laser ablation icp ms microanalytical technique for re os dating of molybdenite the use of a reference or control sample is necessary to establish laboratory credibility and for interlaboratory comparisons the rb sr k ar and 40ar 39ar chronometers are susceptible to chemical and thermal disturbance particularly in terranes that have experienced subsequent episodes of hydrothermal magmatic activity and therefore should not be used as a basis for establishing accuracy in re os dating of molybdenite as has been done in the past re os ages for molybdenite are almost always in agreement with observed geological relationships and when available with zircon and titanite u pb ages for terranes experiencing multiple episodes of metamorphism and deformation molybdenite is not complicated by overgrowths as is common for some minerals used in u pb dating e g zircon monazite xenotime nor are re and os mobilized beyond the margins of individual crystals during solid state recrystallization moreover inheritance of older molybdenite cores incorporation of common os and radiogenic os loss are exceedingly rare whereas inheritance common pb and pb loss are common complications in u pb dating techniques therefore molybdenite ages may serve as point in time markers for age comparisons

natural mass dependent variations in the isotopic composition of molybdenum we present the first observations of natural mass dependent fractionation of the isotopic composition of molybdenum mo using multi collector inductively coupled plasma mass spectrometry variations in the isotopic composition of mo are reported as 97 95mo 97mo 95mo sample 97mo 95mo standard 1 1000 external analytical precision of 97 95mo is 1 between sediments deposited under anoxic conditions 97 95mo 1 02 to 1 52 relative to our in house standard and ferromanganese nodules 97 95mo 0 63 to 0 42 97 95mo of pacific ocean seawater 97 95mo 1 48 lies within the range of values for anoxic sediments closest to modern black sea anoxic sediments molybdenites from continental ore deposits have intermediate 97 95mo ranging from 0 26 to 0 09 variations in the abundances of 92mo 95mo 96mo 97mo and 98mo are consistent with mass dependent fractionation a sporadic unidentified interference occurs at mass 94 and 100mo is not measured we hypothesize that the 97 95mo offset between anoxic sediments and ferromanganese nodules results from mo isotope fractionation during inefficient scavenging of mo from seawater by mn oxides under oxic conditions the similarity in 97 95mo of anoxic sediments and seawater is consistent with the very efficient removal of mo from seawater under anoxic conditions in the presence of h2s the data can be interpreted in terms of a steady state mass balance between the mo flux into the oceans from the continents and the mo flux out of the oceans into oxic and anoxic sediments such an interpretation is quantitatively consistent with existing estimates of the removal fluxes of mo to anoxic and oxic sediments these findings suggest that 97 95mo in seawater may co vary with changes in the relative proportions of anoxic and oxic sedimentation in the oceans and that this variation may be recorded in 97 95mo of anoxic sediments hence the mo isotope system may be useful in paleoredox investigations

a ground uplift in the city of paris france detected by satellite radar interferometry 1 we have analyzed a set of ers 2 images to investigate surface deformation within the city of paris using the radar interferometry technique insar we show that a large scale uplift phenomenon occurred during the summer 1998 south of the saint lazare railway station maximum amplitude of 1 3 cm 0 3 cm this area corresponds to an important underground working site where the piezometric level has been lowered during 1995 and 1997 we show that the uplift correlates in time with the increase of the underground water level during the summer 1998 some ten months after the end of the main water pumping work the amplitude of the uplift corresponds to the amplitude of a subsidence which was previously observed in the same area this suggests that the deformation mechanism is elastic reversible rather than irreversible a simple elastic deformation theoretical model matches the insar measured surface deformation

land subsidence in mashhad valley northeast iran results from insar levelling and gps summary significant land subsidence was recently recognized in northeast iran near the city of mashhad precise levelling surveys performed in 1995 2002 and 2005 indicate as much as 90 cm of subsidence during the 1995 2005 period continuous gps monitoring approximately 8 km northwest of mashhad city shows more than 20 cm yr 1 subsidence between 2005 and 2006 we use interferometric synthetic aperture radar insar measurements to detect the temporal and spatial pattern of this surface deformation 13 interferograms from 10 c band sar images acquired by the enivsat satellite from 2003 to 2005 are analysed and stacked our insar mapping suggests that subsidence occurs within a northwest southeast elongated ellipticshaped bowl along the axis of the mashhad valley with a peak amplitude of 28 30 cm yr 1 for the 2003 2005 time period the insar data indicate that approximately 70 km 2 in the valley floor including the northwestern part of mashhad city subsided at a rate exceeding 15 cm yr 1 between 2003 and 2005 and that the subsidence area is structurally controlled by the trends of quaternary faults cutting the valley floor analysis of piezometric records suggests that subsidence likely results from extensive overdrafting of the aquifer system in the valley that has caused as much as 65 m of water table decline since 1960s

molybdenum evidence for expansive sulfidic water masses in 750 ma oceans abstract the ediacaran appearance of large animals including motile bilaterians is commonly hypothesized to reflect a physiologically enabling increase in atmospheric and oceanic oxygen abundances po 2 to date direct evidence for low oxygen in pre ediacaran oceans has focused on chemical signatures in the rock record that reflect conditions in local basins but this approach is both biased to constrain only shallower basins and statistically limited when we seek to follow the evolution of mean ocean chemical state through time because the abundance and isotopic composition of molybdenum mo in organic rich euxinic sediments can vary in response to changes in global redox conditions mo geochemistry provides independent constraints on the global evolution of well oxygenated environments here we establish a theoretical framework to access global marine mo cycle in the past from the abundance and isotope composition of ancient seawater further we investigate the 750 ma walcott member of the chuar group grand canyon which accumulated in a rift basin with open connection to the ocean iron speciation data from upper walcott shales indicate that local bottom waters were anoxic and sulfidic consistent with their high organic content up to 20 wt similar facies in phanerozoic successions contain high concentrations of redox sensitive metals but in the walcott member abundances of mo and u as well as mo toc 0 5 ppm wt are low 98 mo values also fall well below modern equivalents 0 99 0 13 versus 2 35 today these signatures are consistent with model predictions where sulfidic waters cover 1 4 of the global seafloor corresponding to a 20 80 fold increase compared to the modern ocean therefore our results suggest globally expansive sulfidic water masses in mid neoproterozoic oceans bridging a nearly 700 million year gap in previous mo data we propose that anoxic and sulfidic euxinic conditions governed mo cycling in the oceans even as ferruginous subsurface waters re appeared 800 750 ma and we interpret this anoxic ocean state to reflect a markedly lower atmospheric and oceanic o 2 level consistent with the hypothesis that po 2 acted as an evolutionary barrier to the emergence of large motile bilaterian animals prior to the ediacaran period

the displacement field of the landers earthquake mapped by radar interferometry geodetic data obtained by ground or space based techniques can be used to infer the distribution of slip on a fault that has ruptured in an earthquake although most geodetic techniques require a surveyed network to be in place before the earthquake1 3 satellite images when collected at regular intervals can capture co seismic displacements without advance knowledge of the earthquake s location synthetic aperture radar sar interferometry first introduced4 in 1974 for topographic mapping5 8 can also be used to detect changes in the ground surface by removing the signal from the topography9 10 here we use sar interferometry to capture the movements produced by the 1992 earthquake in landers california11 we construct an interferogram by combining topographic information with sar images obtained by the ers 1 satellite before and after the earthquake the observed changes in range from the ground surface to the satellite agree well with the slip measured in the field with the displacements measured by surveying and with the results of an elastic dislocation model as a geodetic tool the sar interferogram provides a denser spatial sampling 100 m per pixel than surveying methods1 3 and a better precision 3 cm than previous space imaging techniques12 13

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

a re os isotope study of sedimentary rocks and copper gold ores from the ertsberg district west papua indonesia abstract the ores of the ertsberg district consist of both porphyry stockwork and contact controlled mineralization related to the grasberg and ertsberg intrusion centers high grade copper mineralization with gold occurs in skarns on the periphery of each of the intrusion centers the periphery mineralization includes the kucing liar skarn related ores the massive sulfide lenses on the borders of the grasberg intrusive complex and the giant skarn bodies of the deep and intermediate ore zones together with the ores of the dom complex on the margin of the ertsberg diorite the ertsberg orebody the basis of discovery of the district is a copper gold roof pendant of sedimentary strata in the diorite in order to clarify genetic and geochronologic links between the peripheral sediment hosted ore bodies and the intrusion hosted ore bodies re os isotopes of the ores and subjacent precambrian and phanerozoic crust were analyzed re os geochronology of molybdenites was used to resolve the age relationships of the ore bodies the grasberg and kucing liar molybdenites have older molybdenite mineralization ages of 2 88 0 02 ma and 3 01 0 02 ma respectively whereas the ertsberg molybdenite has a younger age of 2 54 0 02 ma these data agree with ar chronologies of the alteration associated with mineralization pollard and taylor 2000 pollard p j taylor r 2000 geochronology of intrusive rocks and cu au mineralization in the ertsberg district in proceedings of freeport institut teknologi bandung itb geological symposium bandung java pp 17 19 and also indicate that the grasberg and kucing liar molybdenites are closely similar in age and older than the ertsberg intrusive system re os data from pyrite chalcopyrite magnetite gold and the surrounding sedimentary rocks from the district define a mixing relationship between samples from the initial stockwork mineralization and peripheral ores of each intrusion center sulfide and oxide minerals from primary stockwork mineralization are isotopically homogeneous and define trends on isochron diagrams with distinct os initial ratios whereas sulfides and oxides taken from peripheral ores are isotopically heterogeneous and define trends on mixing diagrams one possible end member for the mixing is sedimentary rock surrounding the porphyries the measured os ratios of the sedimentary rocks range from 0 52 to 2 21 and overlap the os initial ratios of the sulfides and oxides sampled from both stockwork and contact mineralization the data suggest a model in which the continental crust supplied some of the os and by inference other metals during magma genesis in the lower crust and the remainder came from sedimentary rocks near the intrusion centers

correlation between changes in groundwater levels and surface deformation from gps measurements in the san gabriel valley california 1 changes in groundwater levels cause water bearing basins to deform here we provide a detailed history of horizontal surface displacements in the san gabriel valley california which we show are highly correlated with the water level changes measured at a nearby well correlation coefficient of 0 96 0 01 we use the surface response from a one year period during which water level change in the nearby well was over 16 m to monitor the deformations over a 14 year period from 1998 to 2011 the water level changes lead surface deformation by 21 days but the significance of the offset is only weakly supported p value 0 129 the projection method can be used as a real time monitoring or detection system for deformation caused by a variety of mechanisms such as fluid injection and removal groundwater development oil production carbon sequestration and by seismic and volcanic activity

time dependent land uplift and subsidence in the santa clara valley california from a large interferometric synthetic aperture radar data set 1 we invert 115 differential interferograms derived from 47 synthetic aperture radar sar scenes for a time dependent deformation signal in the santa clara valley california the time dependent deformation is calculated by performing a linear inversion that solves for the incremental range change between sar scene acquisitions a nonlinear range change signal is extracted from the ers insar data without imposing a model of the expected deformation in the santa clara valley cumulative land uplift is observed during the period from 1992 to 2000 with a maximum uplift of 41 18 mm centered north of sunnyvale uplift is also observed east of san jose seasonal uplift and subsidence dominate west of the silver creek fault near san jose with a maximum peak to trough amplitude of 35 mm the pattern of seasonal versus long term uplift provides constraints on the spatial and temporal characteristics of water bearing units within the aquifer the silver creek fault partitions the uplift behavior of the basin suggesting that it acts as a hydrologic barrier to groundwater flow while no tectonic creep is observed along the fault the development of a low permeability barrier that bisects the alluvium suggests that the fault has been active since the deposition of quaternary units

numerical simulation and prediction of regional land subsidence caused by groundwater exploitation in the southwest plain of tehran iran abstract this study characterizes land subsidence in southwest plain of tehran using numerical modeling and predicts the trend through 2018 excessive groundwater withdrawal has caused severe land subsidence in tehran in the past 28 years 1984 2012 groundwater level has decreased 11 65 m the multi layered aquifer system in the southwestern plain of tehran contains three aquifers and three aquitard units the present model was developed simulation using pmwin modflow for windows first groundwater level and land subsidence were simulated for the end of 2004 the model was calibrated using hydraulic head measurements and insar data the simulation results were in fairly good agreement with the measurement results the calibrated and evaluated model was then used to assess the future evolution of land subsidence and for prediction of subsidence through the end of 2018 numerical results show that assuming a constant rate of pumping in the future land subsidence in the southwestern plain of tehran will reach 33 cm by 2018 the study confirmed that land subsidence caused by groundwater pumping is a serious threat to southwest tehran

fractionation of cu and mo isotopes caused by vapor liquid partitioning evidence from the dahutang w cu mo ore field the study presents 65cu and 97mo isotope values from cogenetic chalcopyrite and molybdenite found in veins and breccias of the dahutang w cu mo ore field in china the samples span a 3 4 km range both isotopes show a significant degree of fractionation cu isotope values in the chalcopyrite range from 0 31 to 1 48 and mo isotope values in the molybdenite range from 0 03 to 1 06 for the cogenetic sulfide veined samples a negative slope relationship exists between 65cu and 97mo values which suggest a similar fluid history rayleigh distillation models the vein samples change in isotope values the breccia samples do not fall on the trend thus indicating a different source mineralization event measured fluid inclusion and d and 18o data from cogenetic quartz indicate changes in temperature and mixing of fluids do not appear to cause the isotopic shifts measure related equilibrium processes associated with the partitioning of metal between the vapor fluid in the hydrothermal system could be the probable cause for the relationship seen between the two isotope systems

geodetic tools for hydrogeological surveys 3d displacements above a fractured aquifer from gps time series deep porous reservoirs are subject to charge and discharge of fluids oil gas or water either naturally or induced by human exploitation this leads to a variation in pressure inside the reservoir and consequently to a deformation of the overlying material the knowledge of the ground surface displacements allows inferring the fluid migrations and the hydromechanical properties in the porous reservoir different kinds of geodetic tools are able to measure this ground deformation gps radar interferometry insar tiltmeters or leveling each of them has its own spatial and time characteristics and accuracies that conduct to different kind of applications after a review of the geodetic studies applied to hydrogeological processes we describe two examples of gps time series measurements above the granitic fractured aquifer of ploemeur located in french brittany these time series records the 3d displacements induced by the sum of different processes in this site the involved processes are mainly the ground deformation related to piezometric level variations in the aquifer that we are looking for and the ocean tide loading that can reach several centimeters in the study area we present the protocol of the gps data survey and the processing strategy applied to extract the effect of hydrogeological process with sufficient accuracy two different experiments were studied the long term deformation corresponding to seasonal hydrological cycle and the short term deformation associated to a pumping test for a same variation in piezometric levels the vertical ground displacements show larger amplitude for long term signal than for short one indicating a behavior depending on the duration of the hydrogeological load this difference of reactivity in time can be related to the heterogeneity of the studied aquifer finally this work shows that geodetic measurements provide important constraints for characterizing aquifer system response

geological parameters affected land subsidence in mashhad plain north east of iran mashhad plain is an area with a dry to semi dry climate in razavi khorasan province iran about 60 of 6 million population of the province live in this plain and mainly in mashhad city overexploitation of ground water during the past decades has led to a severe drop in groundwater table and land subsidence in this respect some parts of the plain show an annual groundwater level decline of 1 5 m the surface subsidence features such as rising of the well casing well collapse and tension cracks observed in different parts of the area studying of envisat asar images in a period of 2003 06 30 to 2010 05 24 shows the maximum subsidence rate of 32 cm year in the north west of the mashhad city but there was a mismatch between groundwater drop and ground subsidence in some parts of the plain the evaluation of geological characteristics of subsidence area reveals in addition to the groundwater decline tectonic condition and active faults which change the bedrock depth have a key role in the pattern and rate of subsidence also consolidation of the pleistocene marl bedrock located in the central part of the plain is effective in the increased subsidence rate of the study area

deformation during the 12 november 1999 duzce turkey earthquake from gps and insar data only 87 days after the mw 7 5 17 august 1999 izmit earthquake the duzce earthquake ruptured a ca 40 km long adjoining strand of the north anatolian fault naf system to the east we used displacements of 50 global positioning system gps sites together with interferometric synthetic aperture radar insar range change data spanning the event to estimate the geometry and slip distribution of the coseismic rupture postseismic deformation transients from the duzce earth quake and the preceding i zmit event that are included in some of the measurements are corrected for using dislocation models fit to gps data spanning the various time periods nonlinear inversions for fault geometry indicate that the rupture occurred on a ca 54 north dipping oblique normal right lateral fault distributed slip inver sions indicate maximum strike slip near the center of the duzce fault close to the earthquake hypocenter slip magnitude and depth of faulting decrease to the west and east of the hypocenter both gps and insar data suggest that normal slip is restricted to the shallow portion of the rupture the duzce earthquake had the highest slip to rupture length ratio of any historic earthquake along the naf

synthetic aperture radar interferometry to measure earth s surface topography and its deformation synthetic aperture radar interferometry insar from earth orbiting spacecraft provides a new tool to map global topography and deformation of the earth s surface radar images taken from slightly different viewing directions allow the construction of digital elevation models of meter scale accuracy these data sets aid in the analysis and interpretation of tectonic and volcanic landscapes if the earth s surface deformed between two radar image acquisitions a map of the surface dis placement with tens of meters resolution and subcentimeter accuracy can be con structed this review gives a basic overview of insar for earth scientists and presents a selection of geologic applications that demonstrate the unique capabilities of insar for mapping the topography and deformation of the earth

relationship of pyroclastic volcanism and lake water acidification to jehol biota mass mortality events early cretaceous northeastern china abstract geochemical analysis of the 14 4 m thick lacustrine succession of the lower cretaceous yixian formation jehol group has yielded new insights concerning vertebrate mass mortality events in the lake sihetun volcanic caldera in western liaoning province northeastern china that produced the jehol biota fossil lagerstatten the long term evolution of the caldera system resulted in a shift from felsic to mafic magma chemistry accompanied by a reduced frequency of pyroclastic eruptions declining hydrothermal activity and lower lacustrine productivity the basal tetrapod beds exhibit strong hydrothermal influence as indicated by enrichments of boron b certain alkalis rb cs rare earth elements rees yttrium y and many metals e g co cr cu ge mo ni sb u v and w and by strongly negative molybdenum isotope compositions 98mo to 2 50 that may record large fractionations between molybdate and thiomolybdate species in the sihetun caldera hydrothermal system in contrast the overlying fish beds and non fossiliferous beds have an elemental and mo isotopic composition similar to calc alkaline basalts 98mo 0 29 0 04 in the surrounding watershed suggesting weathering of yixian formation volcanic rocks as the major source of sediment during its

gps measurements of ground deformation induced by water level variations into a granitic aquifer french brittany we used two semi permanent gps receivers with differential configuration to measure the hydrological subsidence of an aquifer used for water supply located on a fractured granitic area the time series of the vertical deformation measurements of the ground surface show a variation of 2 cm between winter and summer we investigate the relationship between this vertical deformation and hydraulic head variations we show that this kind of gps survey allows characterizing part of the hydrological properties of such a heterogeneous aquifer this is thus a new approach of time continuous monitoring of the deformation related to hydrogeological processes

sensing the ups and downs of las vegas insar reveals structural control of land subsidence and aquifer system deformation land subsidence in las vegas nevada united states between april 1992 and december 1997 was measured using spaceborne interferometric synthetic aperture radar the detailed deformation maps clearly show that the spatial extent of subsidence is controlled by geologic structures faults and sediment composition clay thickness the maximum detected subsidence during the 5 75 yr period is 19 cm comparison with leveling data indicates that the subsidence rates declined during the past decade as a result of rising ground water levels brought about by a net reduction in ground water extraction temporal analysis also detects seasonal subsidence and uplift patterns which provide information about the elastic and inelastic properties of the aquifer system and their spatial variability

40ar 39ar and re os geochronology of porphyry copper molybdenum deposits and related copper silver veins in the collahuasi district northern chile the rosario and ujina porphyry cu mo deposits together with porphyry copper mineralization at the nearby quebrada blanca deposit constitute the third largest concentration of copper mineralization associated with the domeyko fault system in northern chile at rosario fault hosted cu ag rich massive sulfide veins are associated with pyrophyllite alunite quartz altered rocks the rosario massive sulfide veins cut biotitealbite magnetite k feldspar and illite chlorite altered rocks associated with porphyry style copper molybdenum mineralization similar massive sulfide veins occur in the la grande area 1 to 2 km south of rosario copper ore at ujina is associated with a k feldspar biotite altered quartz monzonite intrusion the k feldspar biotite assemblage has been overprinted by white mica chlorite alteration new geochronologic data presented in this paper constrain the ages of hydrothermal activity in the rosario and ujina deposits the 40ar 39ar biotite illite and alunite dates at 2 sigma error and a re os molybdenite date at 0 5 error are reported for porphyritic rocks and hydrothermal alteration from the rosario and ujina mineralized centers a weighted mean 40ar 39ar plateau age of 34 4 plus or minus 0 3 ma is obtained for igneous biotite in a monzonite porphyry that hosts copper mineralization at the rosario deposit illite and hypogene alunite from separate overprinting alteration events yielded 40ar 39ar ages of 34 5 plus or minus 0 5 ma plateau age and 32 6 plus or minus 0 3 ma plateau age respectively an re os age of 33 3 plus or minus 0 2 ma for molybdenite at rosario is slightly younger than the 40ar 39ar age of illite but older than the alunite a weighted mean plateau age of 32 7 plus or minus 1 6 ma for hypogene alunite from the la grande cu ag au vein south of rosario is indistinguishable from the age of rosario alunite at ujina the weighted mean 40ar 39ar plateau age of igneous biotite for a monzonite intrusion that hosts copper mineralization is 35 2 plus or minus 0 3 ma the monzonite is intruded by postmineralization porphyry dikes of similar composition from which igneous biotite yielded a 40ar 39ar age of 34 7 plus or minus 0 3 ma igneous biotite in the rosario porphyry cooled through its closure temperature during and after the formation of illite implying that porphyry style ore and alteration minerals in the rosario deposit had formed by 34 3 ma the age of alunite at rosario and la grande indicate that a second discrete episode of hydrothermal activity was superimposed 1 8 plus or minus 0 4 m y later onto the earlier formed porphyry cu system hydrothermal activity at ujina is constrained by the 40ar 39ar ages of igneous biotite in the premineralization and postmineralization intrusions and occurred during a minimum interval of 0 5 plus or minus 0 4 m y the biotite granite at la profunda 1 5 km east of ujina has a igneous biotite age of 81 2 plus or minus 2 9 ma indicating that this intrusion is unrelated to the mineralized eocene oligocene porphyry intrusions at ujina rosario and quebrada blanca the 40ar 39ar data for igneous biotite in the rosario and ujina porphyries are cooling ages after multiple hydrothermal events in most cases these are minimum hydrothermal ages i e ages of the last high temperature hydrothermal event to have affected the samples not magmatic ages however the biotite age for the inca porphyry is possibly only slightly younger than the intrusion age because biotite has not been affected by later hydrothermal alteration

molybdenum isotopes in two indian estuaries mixing characteristics and input to oceans abstract the distributions of dissolved and particulate mo and their isotope composition 98 mo have been measured in the narmada and the tapi estuaries draining into the arabian sea during monsoon the 98 mo of dissolved mo in the narmada estuary ranges from 0 49 to 2 19 in the salinity range 0 17 2 practical salinity unit psu quite similar to that in the tapi estuary 0 99 2 36 in the salinity range 0 20 3 psu mo concentration in suspended sediments of the narmada estuary collected during monsoon average 512 44 ng g range 459 602 ng g similar to that measured in one sample from the tapi estuary 560 ng g mo 98 mo of particulate mo in the narmada ranges from 0 21 to 0 48 with an average 0 03 0 2 dissolved mo in the narmada and the tapi rivers display isotopically heavier m compared to that in basalts the major lithology of their drainage this could result from a variety of processes preferential weathering of mo rich sulphide minerals dispersed in the basalts preferential removal of isotopically lighter mo during transport or contribution from marine cyclic salts supplied via rain or chemical weathering of organic rich shales in the basins the distribution of 98 mo in the narmada and the tapi estuaries with salinity does not follow the theoretical mixing line between river and seawater endmembers suggesting its non conservative behavior particulate mo and 98 mo show concomitant increase with salinity in the narmada estuary indicating loss of dissolved mo by adsorption onto fe mn oxyhydroxide balancing the mo budget along the course of these estuaries using inverse model suggests that in the narmada estuary there could be loss up to 8 of the dissolved mo and that in the tapi supply from anthropogenic sources could be up to 27 the results obtained in this study bring out the processes modifying riverine input of mo and its 98 mo in the estuaries oxic sink in the narmada and anthropogenic input in the tapi repetitive adsorption and desorption of mo in the narmada estuary can modify the supply of dissolved mo and its 98 mo relative to riverine supply by up to 40 this can significantly impact the mo isotope budget of the oceans in contrast in the tapi estuary there is enhancement in the dissolved supply of mo relative to that from river due to anthropogenic input of mo the investigations in these two estuaries underscore the importance of solute particle interactions and anthropogenic input in determining the mo flux and its 98 mo to the open arabian sea

molybdenum isotopic fractionation in the tibetan yulong cu mo deposit and its implications for mechanisms of molybdenite precipitation in porphyry ore systems abstract large variations in mo isotopes up to 2 98mo of molybdenite from many porphyry ore deposits have been reported however the mechanisms of mo isotopic fractionation and their implications for mineralization processes remain poorly understood here we report contrasting mo isotopes of molybdenite formed in two discrete successive mineralizing stages of the giant yulong porphyry cu mo deposit in eastern tibet which when combined with available fluid inclusion data and high precision molybdenite re os ages provide a better understanding in the mechanisms of mo isotopic fractionation and molybdenite precipitation the initial ore forming fluids of both mineralizing stages at yulong exsolved from magmas as a single phase intermediate density fluid which subsequently separated into coexisting brine and vapor phases upon ascent and decompression the relatively uniform mo isotopes 98mo 0 03 0 18 of the early cu mo stage is consistent with the precipitation of molybdenite from relatively stagnant high density brines at shallow levels after phase separation in contrast the large spread of mo isotopes 98mo 0 16 0 60 of the transitional mo stage requires a process similar to instantaneous rayleigh fractionation and suggests molybdenite precipitation from rapidly ascending single phase fluids before phase separation in deep parts of the deposit these arguments imply that the amount of mo precipitation from the single phase fluids likely determines the degree of mo isotopic fractionation further quantitative modeling results suggest that the relatively large mo isotope variation of molybdenite in many porphyry ore deposits may be simply explained by the precipitation of significant amount of mo from the initial single phase fluids therefore apart from the precipitation of molybdenite with economic importance from metal enriched brines that condensed from the single phase fluids the direct precipitation of molybdenite from the single phase fluids may represent another significant mechanism of molybdenite precipitation in porphyry ore systems

space geodetic measurement of crustal deformation in central and southern california 1984 1992 we estimate the velocity field in central and southern california using global positioning system gps observations from 1986 to 1992 and very long baseline interferometry vlbi observations from 1984 to 1991 our core network includes 12 gps sites spaced approximately 50 km apart mostly in the western transverse ranges and the coastal borderlands the precision and accuracy of the relative horizontal velocities estimated for these core stations are adequately described by a 95 confidence ellipse with a semiminor axis of approximately 2 mm yr oriented roughly north south and a semimajor axis of approximately 3 mm yr oriented east west

molybdenum isotope variations in molybdenite vapor transport and rayleigh fractionation of mo molybdenum isotopes in 20 molybdenite samples dated by the re os method and representing a range of geologic settings show mass dependent fractionation spanning 0 63 per atomic mass unit amu previous mo isotope data for molybdenite reveal variations in fractionation of 0 5 amu interpretation of these data is hampered however by limited sample numbers in each study lack of a common standard for interlaboratory comparison and limited range of geologic settings here we show that mo isotope compositions of molybdenites do not correlate with crystallization temperature age geographic distribution or geologic conditions rather rayleigh distillation may explain variations of as much as 0 34 amu in a single molybdenite occurrence exceeding the proposed variability in average continental crust vapor transport and rapid precipitation of mo in propagating fractures may account for isotope fractionation of mo and perhaps other metals at very small scales if so the average isotopic composition of mo at each molybdenite occurrence may be representative of bulk crust our results suggest that the isotopic composition of mo delivered to the oceans is uniform geographically and through geologic time

surface deformation from persistent scatterers sar interferometry and fusion with leveling data a case study over the choushui river alluvial fan taiwan abstract the choushui river alluvial fan craf one of the most important agricultural areas in taiwan suffers severe subsidence caused by groundwater withdrawal we use 20 envisat images from 2006 to 2008 to derive vertical deformation over craf by persistent scatterer interferometry psi which effectively reduces errors affecting conventional dinsar techniques the pixel density over craf is 107 6 pixels km 2 compared to 0 19 points km 2 of the leveling benchmarks psi yields vertical displacements matching the leveling result to 0 6 cm year rms and provides a higher spatial resolution of subsidence than the latter we also develop a data fusion method that considers the high precision low point density leveling result as a smoothed correction to the psi result the combined field is more representative of overall deformation characteristics than the psi only or leveling only field and it is better suited for the assessment of the impact of subsidence over craf

molybdenum isotope evidence for widespread anoxia in mid proterozoic oceans how much dissolved oxygen was present in the mid proterozoic oceans between 1 8 and 1 0 billion years ago is debated vigorously one model argues for oxygenation of the oceans soon after the initial rise of atmospheric oxygen 2 3 billion years ago recent evidence for h 2 s in some mid proterozoic marine basins suggests however that the deep ocean remained anoxic until much later new molybdenum isotope data from modern and ancient sediments indicate expanded anoxia during the mid proterozoic compared to the present day ocean consequently oxygenation of the deep oceans may have lagged that of the atmosphere by over a billion years

mercury and in situ sulfur isotopes as constraints on the metal and sulfur sources for the world s largest sb deposit at xikuangshan southern china it has been well established that metal and sulfur sources in mineral deposits can be very difficult to identify especially for ore deposits hosted in sedimentary rocks using the world s largest sb deposit at xikuangshan in southern china as a case study this study combined hg isotopes and in situ sulfur isotope measurements to constrain the sources of sb and sulfur a variation of 1 1 in 202hg 0 04 to 1 15 was observed in stibnite ore samples suggesting that mass dependent fractionation of hg isotopes occurred during the formation of the deposit significant mass independent fractionation of hg isotopes with 199hg ranging from 0 03 to 0 17 was also observed in the ore samples suggesting that hg transported by the ore fluids was inherited from proterozoic basement metamorphic rocks as these rocks show similar 199hg signatures 0 03 to 0 07 in situ sulfur isotope measurements yielded 34s values that cluster in the range of 6 8 to 10 2 providing evidence that sulfur contained in ore fluids may also have been dominantly derived from underlying proterozoic basement metamorphic rocks 34s 5 6 to 11 5 using the new results from hg and s isotopes we proposed that deep circulated meteoric water mobilized sb hg and s from the proterozoic metamorphic basement ascended along deep faults and subsequently deposited sb at favorable structural zones as a result of boiling of the hydrothermal fluids generating the world class xikuangshan sb deposit this study also highlights the combined use of hg s isotopes as a novel method to provide new and additional insights into the source regions of ore materials for sedimentary hosted sb deposits

late archean cu au mo mineralization at gameleira and serra verde carajas mineral province brazil constraints from re os molybdenite ages new re os molybdenite ages provide constraints on the timing of late archean cu au mo mineralization in the northern carajas mineral province molybdenite from the gameleira iron oxide cu au mo deposit yielded an age of 2 614 14 ma this age overlaps within its analytical error with re os ages of molybdenite from the serra verde cu au mo vein deposit 2 609 13 ma and from the nearby small garimpo fernando gold mining operation 2 592 13 and 2 602 13 ma which is probably related to the latter the geochronological data imply that the hydrothermal cu au mo mineralization in these three deposits was epigenetic and coincides with a regional tectonic regime changing from dextral transtension and clastic sedimentation at 2 7 2 6 ga to sinistral transpression and inversion at 2 6 ga previously reported stable isotope and microthermometric data are compatible with a magmatic affiliation of the cu au mo ores at gameleira and serra verde a genetic relationship of mineralization may therefore exist with 2 56 2 76 ga archean alkaline granitoids or with 2 6 2 7 calc alkaline to tholeiitic volcanic arc type magmatism

absence of molybdenum isotope fractionation during magmatic differentiation at hekla volcano iceland this study investigates the behaviour of molybdenum mo isotopes during magmatic differentiation molybdenum isotope compositions as well as concentrations of rare earth elements and a selection of trace elements have been determined for a well characterised sequence of lavas from hekla volcano iceland covering a compositional range from basalt to rhyolite 46 72wt sio2 and thought to have developed by differentiation and mixing of melts derived from a cogenetic source all samples have identical mo isotopic compositions with an average 98mo of 0 15 0 05 2 s d n 23 there is therefore no resolvable mo isotope fractionation during magmatic differentiation at hekla this finding is supported by the fact that mo remains highly incompatible in hekla lavas increasing from 1 3 to 4 6 g g from basalt to rhyolite indicating that the crystallising phases are extracting only limited amounts of mo from the magma and therefore that significant fractionation of mo isotopes is unlikely it has previously been proposed that cerium ce and mo have similar bulk distribution coefficients and are equally incompatible during mantle melting while both ce and mo remain incompatible in hekla lavas the ce mo ratio decreases from 50 to 36 during magmatic differentiation indicating that mo is more incompatible than ce comparison of mo with other incompatible trace elements indicates that mo is as incompatible as la and slightly less incompatible than k sulphur s decreases strongly from 200 to as low as 2 g g from basalt to andesite and more evolved compositions yet this has no effect on the mo isotopes therefore mo does not exhibit significant chalcophile behaviour in hekla magmas the mo isotopic signature therefore may be used as an indicator of parent magma composition and a potential discriminant of assimilation processes

molybdenum mo stable isotopic variations as indicators of mo attenuation in mine waste rock drainage abstract measurements of molybdenum mo stable isotopes 98mo were applied along with conventional geochemical analyses of water and rock samples at a mo mine in the usa to assess controls on mo mobility in two unsaturated waste rock storage facilities wrsfs that are differentiated by acidic and alkaline drainages unweathered waste rock mo ore and mine tailings from the site were also analyzed to constrain the isotopic composition of the source of mo entering mine drainage via weathering processes the surfaces of weathered waste rock samples were sequentially leached using a two step chemical extraction to determine the distribution and isotopic composition of mo among primary and secondary mineral assemblages the observed variation in 98mo among all samples exceeded 5 the 98mo of mo rich 340 g l mine process water and pit wall runoff ranged from 0 6 to 0 7 which was equal within error to the average 98mo of waste rock tailings and ore samples and indicated negligible isotopic fractionation during molybdenite oxidative dissolution in contrast drainage from the base of both waste rock storage facilities was isotopically heavier ranging from 1 6 to 1 9 coupled 98mo and mo so42 ratios in mine drainage and sequential chemical extractions of weathered waste rock surfaces indicated that mo adsorption onto mineral surfaces was most likely driving the increase in 98mo in drainage from both wrsfs molybdenum stable isotope data provided a powerful tracer of processes controlling mo mobility when used in conjunction with conventional geochemical analyses

satellite radar interferometry time series analysis of surface deformation for los angeles california 1 the los angeles california metropolitan area is a tectonically active region with surface deformation that is a combination of fault related tectonics plus a variety of natural and anthropogenic signals we apply the small baseline subset sbas algorithm to produce an interferometric synthetic aperture radar insar time series analysis for the los angeles area using data acquired by the ers satellites from late 1995 into 2002 the result is a space time deformation product that can be exploited to view not only the smoothly varying long term surface motion but also its time varying patterns large seasonal oscillations of the santa ana aquifer observed in southern california integrated gps network scign data are accurately matched in the insar time series moreover correlations of the insar time series with an annual sinusoid allows us to investigate the dynamics of the hydrologic system index terms 1243 geodesy and gravity space geodetic surveys 1294 geodesy and gravity instruments and techniques 1803 hydrology anthropogenic effects citation lanari r p lundgren m manzo and f casu 2004 satellite radar interferometry time series analysis of surface deformation for los angeles california geophys res lett 31 l23613 doi 10 1029 2004gl021294

on the derivation of coseismic displacement fields using differential radar interferometry the landers earthquake we present a map of the coseismic displacement field resulting from the landers california june 28 1992 earthquake derived using data acquired from an orbiting high resolution radar system we achieve results more accurate than previous space studies and similar in accuracy to those obtained by conventional field survey techniques data from the ers 1 synthetic aperture radar instrument acquired in april july and august 1992 are used to generate a high resolution wide area map of the displacements the data represent the motion in the direction of the radar line of sight to centimeter level precision of each 30 m resolution element in a 113 km by 90 km image our coseismic displacement contour map gives a lobed pattern consistent with theoretical models of the displacement field from the earthquake fine structure observed as displacement tiling in regions several kilometers from the fault appears to be the result of local surface fracturing comparison of these data with global positioning system and electronic distance measurement survey data yield a correlation of 0 96 thus the radar measurements are a means to extend the point measurements acquired by traditional techniques to an area map format the technique we use is 1 more automatic 2 more precise and 3 better validated than previous similar applications of differential radar interferometry since we require only remotely sensed satellite data with no additional requirements for ancillary information the technique is well suited for global seismic monitoring and analysis

poroelastic rebound along the landers 1992 earthquake surface rupture maps of surface displacement following the 1992 landers california earthquake generated by interferometric processing of ers 1 synthetic aperture radar sar images reveal effects of various postseismic deformation processes along the 1992 surface rupture the large scale pattern of the postseismic displacement field includes large lobes mostly visible on the west side of the fault comparable in shape with the lobes observed in the coseismic displacement field this pattern and the steep displacement gradient observed near the emerson camp rock fault cannot be simply explained by afterslip on deep sections of the 1992 rupture models show that horizontal slip occurring on a buried dislocation in a poisson s material produces a characteristic quadripole pattern in the surface displacement field with several centimeters of vertical motion at distances of 10 20 km from the fault yet this pattern is not observed in the postseismic interferograms as previously proposed to explain local strain in the fault step overs peltzer et al 1996b we argue that poroelastic rebound caused by pore fluid flow may also occur over greater distances from the fault compensating the vertical ground shift produced by fault afterslip such a rebound is explained by the gradual change of the crustal rocks poisson s ratio value from undrained coseismic to drained postseismic conditions as pore pressure gradients produced by the earthquake dissipate using the poisson s ratio values of 0 27 and 0 31 for the drained and undrained crustal rocks respectively elastic dislocation models show that the combined contributions of afterslip on deep sections of the fault and poroelastic rebound can account for the range change observed in the sar data and the horizontal displacement measured at global positioning system gps sites along a 60 km long transect across the emerson fault savage and svarc 1997 using a detailed surface slip distribution on the homestead valley kickapoo and johnson valley faults we modeled the poroelastic rebound in the homestead valley pull apart a poisson s ratio value of 0 35 for the undrained gouge rocks in the fault zone is required to account for the observed surface uplift in the 3 5 years following the earthquake this large value implies a seismic velocity ratio vp vs of 2 1 consistent with the observed low vs values of fault zone guided waves at shallow depth li et al 1997 the sar data also reveal postseismic creep along shallow patches of the eureka peak and burnt mountain faults with a characteristic decay time of 0 8 years coseismic dilatant hardening locking process followed by post seismic pore pressure controlled fault creep provide a plausible mechanism to account for the decay time of the observed slip rate along this section of the fault

space geodesy subsidence and flooding in new orleans a subsidence map of the city offers insight into the failure of the levees during hurricane katrina

global positioning system constraints on the active tectonics of ne iran and the south caspian region article history we present a velocity field compiled from a network of 27 permanent and 20 campaign gps stations across ne iran this new gps velocity field helps to investigate how arabia eurasia collision deformation is accommodated at the northern boundary of the deforming zone the present day northward motion decreases eastward from 11 mm yr at tehran 52 e to 1 5 mm yr at mashhad 60 e n s shortening across the kopeh dagh binalud and koh e sorkh ranges sums to 4 5 0 5m m yr at longitude 59 e the available gps velocities allow us to describe the rigid body rotation of the south caspian about an euler pole that is located further away than previously thought we suggest that two new stations mavt and mar2 which are sited far from the block boundaries are most likely to indicate the full motion of the south caspian basin these stations suggest that nw motion is accommodated by right lateral slip on the ashkabad fault at a rate of up to 7 mm yr and by up to 4 6 mm yr of summed left lateral slip across the shahroud left lateral strike slip system our new gps results are important for assessing seismic hazard in ne iran which contains numerous large population centers and possesses an abundant historical earthquake record our results suggest that the fault zones along the eastern alborz and western kopeh dagh may accommodate slip at much faster rates than previously thought fully assessing the role of these faults and the hazard that they represent requires independent verification of their slip rates through additional gps measurements and geological fieldwork

magmatic hydrothermal molybdenum isotope fractionation and its relevance to the igneous crustal signature abstract we analysed the mo isotope composition of a comprehensive series of molybdenite samples from the porphyry type questa deposit nm usa as well as one rhyolite and one granite sample directly associated with the mo mineralization the 98mo of the molybdenites ranges between 0 48 and 0 40 with a median at 0 05 the median mo isotope composition increases from early magmatic 0 29 to hydrothermal 0 05 breccia mineralization median bulk breccia 0 17 to late stockwork veining 0 22 moreover variations of up to 0 34 are found between different molybdenite crystals within an individual hand specimen the rhyolite sample with 0 12 g g 1 mo has 98mo 0 57 and is lighter than all molybdenites from the questa deposit interpreted to represent the igneous leftover after aqueous ore fluid exsolution we recognize three mo isotope fractionation processes that occur between about 700 and 350 c affecting the mo isotope composition of magmatic hydrothermal molybdenites 1mo minerals preferentially incorporate light mo isotopes during progressive fractional crystallization in subvolcanic magma reservoirs leaving behind a melt enriched in heavy mo isotopes 2mo magmatic hydrothermal fluids preferentially incorporate heavy mo isotopes upon fluid exsolution 3mo light mo isotopes get preferentially incorporated in molybdenite during crystallization from an aqueous fluid leaving behind a hydrothermal fluid that gets heavier with progressive molybdenite crystallization the sum of all three fractionation processes produces molybdenites that record heavier 98mo compositions than their source magmas this implies that the mean 98mo of molybdenites published so far 0 4 likely represents a maximum value for the mo isotope composition of phanerozoic igneous upper crust

present day strain distribution across a segment of the central bend of the north anatolian fault zone from a persistent scatterers insar analysis of the ers and envisat archives

molybdenum geochemistry in a seasonally dysoxic mo limited lacustrine ecosystem lakes are important for storage of the essential micronutrient molybdenum mo during its transfer from the continents to the oceans but little is known about the major sources and sinks for mo in lacustrine ecosystems we studied mo cycling in castle lake a small subalpine lake in the klamath siskiyou mountains of northern california underlain primarily by mafic and ultramafic rocks where primary productivity is limited by mo bioavailability the deeper water of the lake becomes dysoxic 9 90 m dissolved oxygen during the summer this study was undertaken to identify the sources of mo to castle lake and establish a mo budget we measured mo concentrations in a suite of bulk solids lake sediments soils and bedrock and aqueous samples sediment porewaters soil runoff spring waters snow and ice from castle lake and its watershed lake sediments have elevated mo 7 36 ppm compared to soils and bedrock 0 2 2 ppm and mo al values were nearly two orders of magnitude higher than the crustal abundance sediment porewaters had higher mo 4 15 nm than lake water 2 4 nm soil runoff 0 1 6 2 nm snowmelt 0 1 nm lake ice 0 3 2 2 nm and local spring waters 0 03 2 72 nm bulk lake sediments had negative 98 95 mo values ranging from 0 5 to 1 0 0 1 we used the numerical model profile to estimate the net reaction rate of mo in the porewater model calculations ruled out diagenesis as a source of mo to lake sediments diagenetic mo always represented 5 of the total mo content in sediment we also ruled out dissolved mo inputs from groundwater and watershed inflow as important sources of mo two whole lake experimental mo additions in the 1960 s could have contributed a sizeable amount of mo to the lake sediments but only over a short period atmospheric deposition of anthropogenic mo from extensive copper smelting that occurred south of castle lake from 1896 to 1919 and from major californian urban centers today were negligible mo sources mo flux from the sediments 0 4 0 5 nmol cm 2 yr 1 was roughly equal to mo fluxes from surface inflow and outflow whereas mo burial fluxes were significantly higher 11 5 nmol cm 2 yr 1 because dissolved mo fluxes were minimal and atmospheric mo deposition was estimated to be a minor source of mo 1 nmol cm 2 yr 1 the largest source of mo is non detrital particulate matter 12 nmol cm 2 yr 1 likely a mixture of organic matter and fe mn oxyhydroxides as supported by mo isotopic data

the molybdenum isotopic compositions of i s and a type granitic suites this study reports mo isotopic compositions for fifty two palaeozoic granitic rocks with contrasting source affinities a i and s type from the lachlan fold belt lfb and the new england batholith neb both in se australia and three compositionally zoned plutons loch doon criffell and fleet located in the southern uplands of scotland the results show relatively large variations in 98mo for igneous rocks ranging from 1 73 to 0 59 with significant overlaps between different types no relationships between 98mo and 18o or asi alumina saturation index are observed indicating that mo isotopes do not clearly distinguish igneous vs sedimentary source types instead effects of igneous processes source mixing regional geology as well as hydrothermal activity control the mo isotope compositions in these granites it is found that mo is mainly accommodated in biotite and to a lesser extent in hornblende hornblende and fe3 rich minerals may preferentially incorporate light isotopes as reflected by negative correlations between 98mo and k rb and fe2o3 there is a positive correlation between initial 87sr 86sr and 98mo in i type granitic rocks reflecting the admixing of material from isotopically distinct sources granitic rocks from scotland and australia display strikingly similar curvilinear trends in 98mo vs initial 87sr 86sr despite the differing regional geology localized hydrothermal effects can result in low 98mo in granite as seen in three samples from loch doon and criffell which have anomalously light 98mo of 1 based on this study an estimate of 98mo 0 14 0 07 95 s e for the phanerozoic upper crust is proposed this is slightly heavier than basalts indicating an isotopically light lower crust and or a systematic change to the crust resulting from subduction of isotopically light dehydrated slab and or pelagic sediment over time

from the roots to the roof an integrated model for the neoarchean carajas iocg system brazil abstract the carajas mineral province located in northern brazil comprises the oldest iron oxide copper gold mineralizing system on earth and is one of the world s most significant cluster of large tonnage iocg deposits based on a critical assessment of the literature a new integrated model for the carajas neoarchean iocg deposits the model considers the hydrothermal alteration footprint and the rock textures the geometry of the mineralization and the ore assemblage and the isotopic and geochronological signature the majority of the deposits form in the hypozonal domain pervasive and well developed sodic magnesian and calcic iron hydrothermal alteration halos form through magmatic derived hydrothermal fluids the occurrence of hydrothermal orthopyroxene marialite in the ni rich gt 34 and salobo deposits extend further the p t boundaries to temperatures of up to 700 c and 5 kbars thus co is proposedrresponding to the root zone of the system epizonal deposits conversely are characterized by low temperature potassic biotite phlogopite propylitic and chloritic hydrolytic hydrothermal assemblages towards shallower crustal levels although a mantle contribution to the hydrothermal fluids is recognized the o b stable isotopic signature reveals the participation of surface derived basinal brines in the ore forming process the occurrence of polymetallic ooids in the alemao orebody igarape bahia deposit hosting identical hydrothermal alteration mineralogy to the chalcopyrite breccias of other iocg deposits in the carajas mineral province suggests that the mineralizing fluids may have reached the paleo surface of the carajas basin in the neoarchean representing the roof of the iocg system conversely the ore mineralogy is consistent throughout the vertical scheme magnetite is the only iron oxide formed and precipitate from iron rich hydrothermal alteration accompanying the calcic alteration similarly chalcopyrite represents the cu sulfide there is no transition to more oxidized assemblages towards shallower zones supporting that the overall system was relatively reduced since more oxidizing phases hematite bornite are not observed as part of the neoarchean iocg system thus the neoarchean carajas iocg system represents a crustal scale continuum of a vertical paleo hydrothermal system formed coevally to the voluminous bimodal magmatism and the formation of the world class banded iron formation hosted iron ore

seasonal subsidence and rebound in las vegas valley nevada observed by synthetic aperture radar interferometry analyses of areal variations in the subsidence and rebound occurring over stressed aquifer systems in conjunction with measurements of the hydraulic head fluctuations causing these displacements can yield valuable information about the compressibility and storage properties of the aquifer system historically stress strain relationships have been derived from paired extensometer piezometer installations which provide only point source data because of the general unavailability of spatially detailed deformation data areal stress strain relations and their variability are not commonly considered in constraining conceptual and numerical models of aquifer systems interferometric synthetic aperture radar insar techniques can map ground displacements at a spatial scale of tens of meters over 100 km wide swaths insar has been used previously to characterize larger magnitude generally permanent aquifer system compaction and land subsidence at yearly and longer timescales caused by sustained drawdown of groundwater levels that produces intergranular stresses consistently greater than the maximum historical stress we present insar measurements of the typically small magnitude generally recoverable deformations of the las vegas valley aquifer system occurring at seasonal timescales from these we derive estimates of the elastic storage coefficient for the aquifer system at several locations in las vegas valley these high resolution measurements offer great potential for future investigations into the mechanics of aquifer systems and the spatial heterogeneity of aquifer system structure and material properties as well as for monitoring ongoing aquifer system compaction and land subsidence

rhenium osmium evidence for regional mineralization in southwestern north america more than 40 base metal porphyry ore deposits in southwestern north america are associated with the laramide orogeny about 90 million to 50 million years ago rhenium osmium dates on molybdenite a rhenium enriched sulfide common in many of the deposits reveal that in individual deposits mineralization occurs near the final stages of magmatic activity irrespective of the time of inception magnitude or duration of magmatism deposits that differ widely in location and in the extent and timing of magmatism have nearly identical ages for mineralization rhenium osmium ages suggest that mineralization occurred during two distinct intervals from about 74 million to 70 million years ago and from 60 million to 55 million years ago most deposits that formed in the oldest interval are within the older precambrian basement of northwestern arizona whereas the younger deposits are restricted to the younger precambrian basement in southern arizona and northern mexico synchronous widespread mineralization indicates that similar crust mantle interaction occurred on a regional scale for ore deposits once thought to be the product of localized processes

the geology and geochronology of the waifangshan mo quartz vein cluster in eastern qinling china abstract the waifangshan mo quartz vein cluster occurs at the northernmost margin of the qinling orogen the orebodies occur as quartz veins and are controlled by low angle faults we identify three hydrothermal stages characterized by veinlets of quartz pyrite quartz molybdenite pyrite chalcopyrite galena sphalerite and quartz carbonate assemblages respectively the early stage quartz veins were structurally deformed brecciated and filled by non deformed middle or late stage veinlets suggesting that the mineralization is associated with a tectonic transition from compression to extension five molybdenite separates from the zhifang mo deposit yield individual re os ages from 241 2 1 6 to 247 4 2 5 ma with a weighted mean age of 243 8 2 8 ma individual re os isotope ages of four molybdenite samples from the badaogou mo deposit range from 238 9 2 1 to 255 8 2 2 ma with a weighted mean age of 246 10 ma four analyses of molybdenite separates from the xiangchungou mo deposit yield individual re os isotope ages of 243 8 8 8 to 247 7 4 4 ma with a weighted mean age of 246 0 1 1 ma all of these data yield a weighted mean age of 241 9 1 9 ma coeval with the accretionary orogeny we thus conclude that the waifangshan mo quartz veins formed during a transition from continental arc to back arc setting the waifangshan mo quartz veins share similar geological geochemical and geochronological features with the orogenic type systems we propose that the waifangshan mo quartz veins are an orogenic type mo mineralization and possibly represent the deepest member in the crustal continuum model of the orogenic type mineral systems the molybdenite samples from the mo quartz veins in the waifangshan area have low re contents 1 457 to 39 16 ppm suggesting a continental crust dominated source

quantifying groundwater exploitation induced subsidence in the rafsanjan plain southeastern iran using insar time series and in situ measurements abstract decades of groundwater overexploitation for agriculture and industrial development have resulted in substantial land subsidence in the rafsanjan plain of southeastern iran this work presents the results of an insar time series analysis obtained by the exploitation of envisat alos and sentinel 1 s1 sar data archives between june 2004 and may 2016 to investigate land subsidence in the plain the insar analysis revealed an area of approximately 1000 km 2 within the study area showing subsidence of 5 cm year and locally exceeding 30 cm yr in the last decade this area of significant subsidence is limited in its spatial extent to the agricultural land and is partly influenced by quaternary faults the temporal and areal relationships of subsidence and groundwater level data suggest that a significant part of the observed subsidence in the rafsanjan region is caused by intense groundwater extraction that has led to widespread compaction within the upper parts of the up to 300 m thick unconsolidated sediments causing irreversible and inelastic deformation of the aquifer the average volume storage loss of the aquifer system due to overexploitation is estimated to have been approximately 300 million cubic metre mcm yr over the last decade

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

radar interferogram filtering for geophysical applications the use of sar interferometry is often impeded by decorrelation from thermal noise temporal change and baseline geometry power spectra of interferograms are typically the sum of a narrow band component combined with broad band noise we describe a new adaptive filtering algorithm that dramatically lowers phase noise improving both measurement accuracy and phase unwrapping while demonstrating graceful degradation in regions of pure noise the performance of the filter is demonstrated with sar data from the ers satellites over the jakobshavns glacier of greenland

variation of mo isotopes from molybdenite in high temperature hydrothermal ore deposits measurable molybdenum isotope fractionation in molybdenites from different ore deposits through time provides insights into ore genesis and a new technique to identify open system behavior of re os in molybdenites molybdenite samples from six porphyry copper deposits one epithermal polymetallic vein deposit four skarns and three fe oxide cu au deposits were analyzed the 97mo where open image in new window for all samples varied from 1 34 0 09 to 0 26 0 04 this is the largest molybdenum isotopic variation in molybdenite from high temperature ore deposits recorded to date 97mo of molybdenite varies as a function of the deposit type and the rhenium and osmium concentrations of the samples isotope values for mo also vary within the individual deposits in general molybdenites from porphyry copper deposits have the lightest values averaging 0 07 0 23 1 molybdenites from the other deposit types average 0 49 0 26 1 the variations could be related to the fractionation of mo into different mineral phases during the ore forming processes a comparison of the mo isotope ratios and the re os ages obtained from the same aliquot may possess a geochronological evaluation tool samples that yielded robust ages have different mo isotopic compositions in comparison to samples that yielded geologically unreasonable ages another observed relationship between the re os and mo isotope data reveals a weak correspondence between re concentration and mo isotope composition molybdenites with higher concentrations of re correspond to lighter mo isotope values

variation of molybdenum isotopes in molybdenite from porphyry and vein mo deposits in the gangdese metallogenic belt tibetan plateau and its implications we present mo isotopic ratios of molybdenite from five porphyry molybdenum deposits chagele sharang jiru qulong and zhuonuo and one quartz molybdenite vein type deposit jigongcun along the gangdese metallogenic belt in the tibetan plateau these deposits represent a sequence of consecutive events of the india asia collision at different periods additional molybdenite samples from the henderson mo deposit usa the oceanic subduction related el teniente chile and bingham usa porphyry cu mo deposits were analyzed for better understanding the controls on the mo isotope systematics of molybdenite the results show that molybdenite from sharang jiru qulong and zhuonuo deposits have similar 97mo 0 in agreement with the values of the henderson mo deposit 0 10 in contrast samples from the changle and jigongcun deposit have 97mo of 0 85 to 0 88 and 0 48 respectively molybdenite from the el teniente and bingham deposits yields intermediate 97mo of 0 27 and 0 46 respectively the mo isotopes combined with nd isotope data of the ore bearing porphyries indicate that source of the ore related magmas has fundamental effects on the mo isotopic compositions of molybdenite our study indicates that molybdenite related to crustal and mantle derived magmas has positive or negative 97mo values respectively whereas molybdenite from porphyries formed by crust mantle mixing has 97mo close to 0 it is concluded that the mo isotope composition in the porphyry system is a huge source signature without relation to the tectonic setting under which the porphyry deposits formed

rapid subsidence over oil fields measured by sar interferometry the lost hills and belridge oilfields are in the san joaquin valley california the major oil reservoir is high porosity and low permeability diatomite extraction of large volumes from shallow depths causes reduction in pore pressure and subsequent compaction forming a surface subsidence bowl we measure this subsidence from space using interferometric analysis of sar synthetic aperture radar data collected by the european space agency remote sensing satellites ers 1 and ers 2 maximum subsidence rates are as high as 40 mm in 35 days or 400 mm yr measured from interferograms with time separations ranging from one day to 26 months the 8 and 26 month interferograms contain areas where the subsidence gradient exceeds the measurement possible with ers sar but shows increased detail in areas of less rapid subsidence synoptic mapping of subsidence distribution from satellite data powerfully complements ground based techniques permits measurements where access is difficult and aids identification of underlying causes

rhenium behavior in molybdenite in hypogene and near surface environments implications for re os geochronometry abstract rhenium is concentrated mainly in molybdenite mos2 and occurs as a major cation in only a few rare minerals this affinity makes molybdenite an ideal mineral for re os geochronometry but research on the behavior of re in molybdenite is limited infrared microscope xrd back scattered electron bse and microprobe techniques have been used in this study to document re behavior in molybdenite affected by hypogene and near surface processes in the hypogene environment both 3r and 2h molybdenite can experience re loss during hydrothermal alteration which also causes increased infrared transparency ir alteration at temperatures as low as 150 c can cause re loss in the presence of advecting fluids and will affect re os dating if it occurs long after primary mineralization re loss in 3r and 2h molybdenite under supergene conditions does not increase ir transparency rhenium is not incorporated into supergene ferrimolybdite but is enriched in k al silicate intergrowths which may be illite these minute intergrowths are present in several samples and would not be detected in a simple optical examination in the supergene environment elemental os is stable whereas re is not rhenium in molybdenite may be removed by supergene fluids after some has decayed to 187os causing erroneously old ages or it may be adsorbed into the illite intergrowths creating ages which are too young in the weathering environment proterozoic molybdenites have altered to re enriched powellite which can be detected using back scattered electron imagery combined microprobe xrd bse and infrared microscopy can be successfully used to detect alteration in molybdenite prior to dating these techniques are non destructive and should be performed before any molybdenite is dated by the re os system

coseismic deformation from the 1999 mw 7 1 hector mine california earthquake as inferred from insar and gps observations we use interferometric synthetic aperture radar insar and global positioning system gps observations to investigate static deformation due to the 1999 m w 7 1 hector mine earthquake that occurred in the eastern california shear zone interferometric decorrelation phase and azimuth offset measurements indicate regions of surface and near surface slip which we use to constrain the geometry of surface rupture the inferred geometry is spatially complex with multiple strands the southern third of the rupture zone consists of three subparallel segments extending about 20 km in length in a n45 w direction the central segment is the simplest with a single strand crossing the bullion mountains and a strike of n10 w the northern third of the rupture zone is characterized by multiple splays with directions subparallel to strikes in the southern and central the average strike for the entire rupture is about n30 w the interferograms indicate significant along strike variations in strain which are consistent with variations in the ground based slip measurements using a variable resolution data sampling routine to reduce the computational burden we invert the insar and gps data for the fault geometry and distribution of slip we compare results from assuming an elastic half space and a layered elastic space results from these two elastic models are similar although the layered space model predicts more slip at depth than does the half space model the layered model predicts a maximum coseismic slip of more than 5 m at a depth of 3 to 6 km contrary to preliminary reports the northern part of the hector mine rupture accommodates the maximum slip our model predictions for the surface fault offset and total seismic moment agree with both field mapping results and recent seismic models the inferred shallow slip deficit is enigmatic and may suggest that distributed inelastic yielding occurred in the uppermost few kilometers of the crust during or soon after the earthquake