persistent scatterer interferometric synthetic aperture radar for crustal deformation analysis with application to volcan alcedo galapagos 1 while conventional interferometric synthetic aperture radar insar is a very effective technique for measuring crustal deformation almost any interferogram includes large areas where the signals decorrelate and no measurement is possible persistent scatterer ps insar overcomes the decorrelation problem by identifying resolution elements whose echo is dominated by a single scatterer in a series of interferograms existing ps methods have been very successful in analysis of urban areas where stable angular structures produce efficient reflectors that dominate background scattering however man made structures are absent from most of the earth s surface furthermore existing methods identify ps pixels based on the similarity of their phase history to an assumed model for how deformation varies with time whereas characterizing the temporal pattern of deformation is commonly one of the aims of any deformation study we describe here a method for ps analysis stamps that uses spatial correlation of interferogram phase to find pixels with low phase variance in all terrains with or without buildings prior knowledge of temporal variations in the deformation rate is not required for their identification we apply stamps to volcan alcedo where conventional insar fails because of dense vegetation on the upper volcano flanks that causes most pixels to decorrelate with time we detect two sources of deformation the first we model as a contracting pipe like body which we interpret to be a crystallizing magma chamber the second is downward and lateral motion on the inner slopes of the caldera which we interpret as landsliding

geometric and kinematic models for detachment folds with fixed and variable detachment depths abstract detachment folds are defined by competent rock units and are cored by incompetent units deformed internally above a detachment horizon we have developed two geometric models to constrain possible geometries and kinematic paths for ideal detachment folds the models each independently relate fold geometry to shortening and to detachment depth model assumptions include plane strain constant competent bedlength constant cross sectional area chevron fold geometry and no bed parallel shear outside the fold detachment depth is constant in one model but may vary in the other thus allowing evaluation of the implications for fold geometry and kinematics of fixed vs variable detachment depth detachment folds formed above a detachment unit of constant thickness constant detachment depth must be initially symmetrical and cannot grow with fixed hinges fixed arc length or a self similar geometry detachment folds formed above a detachment unit of variable thickness variable detachment depth must also be initially symmetrical but any one fold geometry can have a range of possible initial and final detachment depths kinematic paths for folds with fixed hinges fixed arc lengths migrating hinges variable arc lengths and selfsimilar geometries are all possible if detachment depth varies the change in detachment depth during deformation can be determined using the variable detachment depth model if either initial or final detachment depth is known the models demonstrate a wider range of variability in the geometry and kinematics of ideal detachment folds particularly for the variable depth model than is the case for ideal fault bend and fault propagation folds this variability limits the usefulness of simple geometric models for reconstructing the geometry of natural detachment folds balancing cross sections over a sufficient area and evaluating strain may compensate for these limitations

geometric analysis of fold development in overthrust terranes abstract fault bend folding fault propagation folding and detachment or decollement folding are three distinct scenarios for fold thrust interaction in overthrust terranes simple kink hinge models are used to determine the geometric associations implicit in each scenario bedding maintains constant thickness in the models except in the forelimb of the fold the forelimb is allowed to thicken or thin without limit the models address individual folds and the calculated fold geometries are balanced structures each mode of fold thrust interaction has a distinct set of geometric relationships final fold geometry is adequate in itself to discern many fault bend folds this is not the case for fault propagation and detachment folds these two fold forms have very similar geometric relationships some knowledge of the nature of the underlying thrust or decollement zone is usually needed to distinguish between them the geometry of a fold is altered in a predictable fashion by transport through an upper ramp hinge and by fault parallel shearing of the structure the shearing results in a tighter fold whereas transport through the ramp hinge produces a broader fold the viability of the geometric analysis technique is demonstrated through its application to a pair of detachment folds from the canadian cordillera the geometric analysis is also used to evaluate cross sections through subsurface structures in an example from the turner valley oil field the analysis indicates how the interpretation should be altered so as to balance the cross section the analysis reveals hidden assumptions and specific inconsistencies in structural interpretations

subsidence measurements in roads and implementation in land use plan optimisation in areas affected by deep coal mining this paper presents a study of 12 year monitoring of ground subsidence along a selected road affected by subsidences trough induced by underground black coal mining in the largest mining district in the czech republic the major scientific contribution of this study is that it suggests a new methodology that involves independent observation of a subsidence trough in the linear direction a road permitting determination of the ground deformation parameters and related building site categories in areas affected by deep coal mining it is vital to update the current status of the building site categories which represent the zones of potential hazard posed to the existing structures or future development it is possible to identify the actual conditions in the localities using systematical measurements along roads which are in any case required for periodical maintenance in areas of underground mining prognoses may be subsequently optimised in this way and investors property owners and mining companies may benefit through saving on costs associated with subsidence damage in fact there are two eventualities i e the conditions either improve or deteriorate the latter occurred in the case of the study area in the beginning the majority of the study area i e 91 belonged to the most suitable category of building sites which means that development was possible without any restrictions at the end of the observation the measurements showed a prominent fall of the subsidence trough and as much as 19 of the area fell into the least suitable categories i or ii where development is prohibited the publication recommends that mining companies use road monitoring as an independent monitoring tool to determine the hazard in regions affected by deep coal mining it is possible to conveniently verify the prognostic maps in land use planning in this way

effects of firn ventilation on isotopic exchange a new model of isotopic diffusion in the upper few meters of firn tracks the isotopic composition of both the ice matrix and the pore space vapor through time in two dimensions stable isotopes in the vapor phase move through the firn by diffusion along concentration gradients and by advection wind driven ventilation carries atmospheric water vapor into the firn where it mixes with existing pore space vapor unlike previous models our model allows disequilibrium between pore space vapor and the surrounding snow grains we also calculate the isotopic effects of ventilation driven sublimation and condensation in the firn model predictions of isotopic diffusion in firn compare favorably with existing diffusion models model results quantify what other investigators have suggested isotopic change in the upper few meters is more rapid than can be explained by the whillans and grootes 1985 model isotopic equilibration with atmospheric vapor is an important component of post depositional isotopic change and ventilation enhances isotopic exchange by creating regions of relatively rapid sublimation and condensation in the firn

effect of periodic melting on geochemical and isotopic signals in an ice core from lomonosovfonna svalbard 1 we examine the quality of atmospherically deposited ion and isotope signals in an ice core taken from a periodically melting ice field lomonosovfonna in central spitsbergen svalbard the aim is to determine the degree to which the signals are altered by periodic melting of the ice we use three diagnostics 1 the relation between peak values in the ice chemical and isotopic record and ice facies type 2 the number of apparent annual cycles in these records compared with independently determined number of years represented in the ice core and 3 a statistical comparison of the isotopic record in the ice core and the isotope records from coastal stations from the same region we find that during warm summers as much as 50 of the annual accumulation may melt and percolate into the firn in a median year this decreases to similar to25 as a consequence of percolation the most mobile acids show up to 50 higher concentrations in bubble poor ice facies compared with facies that are less affected by melt most of the other chemical species are less affected than the strong acids and the stable water isotopes show little evidence of mobility annual or biannual cycles are detected in most parameters and the water isotope record has a comparable statistical distribution to isotopic records from coastal stations we conclude that ice cores from sites like lomonosovfonna contain a useful environmental record despite melt events and percolation and that most parameters preserve an annual or in the worst cases a biannual atmospheric signal

snow isotope diffusion rates measured in a laboratory experiment the diffusion of stable water isotopes in snow was measured in two controlled laboratory experiments two batches of snow of different isotopic composition were stacked alternately with varying layer thicknesses the stack was stored in a freezer room at constant temperature for several months and sampled at regular intervals to analyse the diffusion measured isotope profiles were fitted to a theoretical model with diffusion length as the fit parameter in the first experiment we observed a difference in diffusion rates between layers of different thicknesses which is likely caused by layers of snow not being in proper contact with each other in the second experiment we found very good agreement between measurements and model results the measured diffusivity is compared with theory in which we mainly focus on the temperature dependence of the ice vapour fractionation factors this temperature dependence is slightly different for the different isotopes of water which leads to a difference in diffusion rates we illustrate how our set up can be used to measure the ratio between ice vapour fractionation factors of oxygen 18 and deuterium which determine the relation between the difference in diffusion and the firn temperature

chaotic obliquity and the nature of the martian climate recent calculations of the martian obliquity suggest that it varies chaotically on timescales longer than about 107 years and varies between about 0 and 60 we examine the seasonal water behavior at obliquities between 40 and 60 up to several tens of centimeters of water may sublime from the polar caps each year and possibly move to the equator where it is more stable co2 frost and co2 h2o clathrate hydrate are stable in the polar deposits below a few tens of meters depth so that the polar cap could contain a significant co2 reservoir if co2 is present it could be left over from the early history of mars also it could be released into the atmosphere during periods of high obliquity causing occasional periods of more clement climate

reconstruction of three centuries of annual accumulation rates based on the record of stable isotopes of water from lomonosovfonna svalbard we use the upper 81 in of the record of stable isotopes of water from a 122 in long ice core from lomonosovfonna central spitsbergen svalbard to construct an ice core chronology and the annual accumulation rates over the icefield the isotope cycles are counted in the ice core record using a model that neglects short wavelength and low amplitude cycles we find approximately the same number of delta 18 o cycles as years between known reference horizons and assume these cycles represent annual cycles testing the validity of this assumption using cycles in deltad shows that both records give similar numbers of cycles using the delta 18 o chronology and decompressing the accumulation records using the nye flow model we calculate the annual accumulation for the ice core site back to ad 1715 we find that the average accumulation rate from 1715 to 1950 was on average 0 30 in w e accumulation rates increased about 25 during the later part of the 20th century to an average of 0 41 in w e for the period 1950 97 the accumulation rates show highly significant 2 1 and 21 year periodicities which gives credibility to our time scale

the role of strain in area constant detachment folding abstract the classical constant area relationship for balancing cross sections is reformulated to accommodate layer parallel strain leading to a general equation for the layer parallel strain in a fold formed above a stratigraphically fixed detachment horizon the strain required for area balance can be calculated from a knowledge of the fold shape and the depth to detachment the strains predicted from a simple kinematic model are realistic in the order of 10 30 layer parallel shortening the strain may be penetrative or occur as small scale disharmonic folds and faults the tip top anticline a fold at the leading edge of the wyoming thrust belt is used to illustrate the applicability of this reformulation the computed layer parallel strains in the well controlled upper portion of the structure are less than 5 because most of the shortening is accommodated by second order folds and faults

monitoring of coal mining subsidence in peri urban area of zonguldak city nw turkey with persistent scatterer interferometry using alos palsar this paper presents the results of spatiotemporal monitoring of surface subsidence over a mining area in zonguldak province of turkey using synthetic aperture radar sar data providing maps of subsidence rates in the radar line of sight direction a total of 18 sar images acquired between january 2007 and june 2010 by the japanese advanced land observing satellite have been used to map the surface displacements using the persistent scatterer interferometry technique the use of phased array type l band synthetic aperture radar data has proved useful for avoiding signal decorrelation and estimating surface deformation in the heavily vegetated study region the technique enables the monitoring of continuous small displacements over a large area our findings present that many persistent scatterers were located on the vegetation cover the results reveal areas of ground surface subsidence up to 44 mm year that are well correlated with the underground coal mining galleries particularly in the gelik region where the karadon mining galleries are present

calibrating the ice core paleothermometer using seasonality high resolution oxygen isotope measurements on the dome summit south dss ice core from law dome antarctica provide a seasonal profile that is sufficiently stable and undistorted by biases in accumulation to permit comparison with measured temperature seasonality this comparison yields an isotope temperature relation with a gradient d dt of 0 44 0 02 c and provides a new method for exploring the isotope temperature relationship at high accumulation sites if applied to the observed isotope record from the dss core which extends through the last glacial and beyond this calibration suggests that at its coldest the last glaciation was 13 c colder than present at this site after correcting for elevation change this finding compares with a temperature difference of 8 c computed by using the local spatially derived calibration

a hydraulic gradient similitude testing system for studying the responses of a laterally loaded pile and soil deformation in this study a newly developed hydraulic gradient similitude hgs test and the particle image velocimetry piv technique were applied to a laterally loaded pile to simultaneously measure the responses of a laterally loaded pile and sand displacement fields in a high body force field a comparison of the stages in the hgs test indicated that the lateral displacement of the loading point was doubled and that the applied load increased by 54 these results indicate that the rate of load increase gradually decreases with the increased displacement due to the plastic behavior of the soil in addition soil deformation increased as the lateral load increased the soil behind the pile moved downwards because the resistance of the pile decreased and the soil near the ground in front of the pile moved upwards because the movement of the pile caused the soil to resist lateral movement the authors provide an additional model test for saturated soils under hydrostatic conditions i e 1 g to study the effects of the hydraulic gradient on the response of the pile and sand deformation this comparison indicated that the lateral load in the hgs test was 4 2 times greater than that in the 1 g model test with a displacement of 3 82 mm times the loading point in addition the magnitudes of the deflection were smaller than those in the 1 g model test when the self weight stress was increased 11 times the passive influence zone in front of the pile in the 1 g model test was 50 greater than that in the hgs test in addition the sand displacement around the pile in the 1 g model test was greater than that in the hgs test the main reason for the abovementioned results are that the relative stiffness ratio between the soil and pile increased as the hydraulic gradient increased ultimately this study shows that the piv technique can be used to accurately measure soil displacement and represent pile deflection under different body forces this study increases our understanding of the responses of soil to a laterally loaded pile and of soil deformation in a high body force field the results of this study demonstrate that the developed hgs device and the combination of the hgs and piv techniques are suitable for solving soil pile interaction problems

investigation on 3d ground deformation and response of active and passive piles in loose sand two scaled model tests were carried out to investigate the pile soil pile interaction during a lateral loading process two instrumented piles termed the active pile and the passive pile were installed into loose sand the active pile head was subjected to lateral loads and the passive pile was set at twice pile width away from the active pile center to study the effect of the direction of lateral loading on the pile soil pile interaction the passive pile was set in front of and behind the active pile in tests 1 and 2 respectively experimental results showed that the leading passive pile produced much stronger effects on surrounding ground deformation and on response of active pile as compared with the trailing passive pile the intermediate soil between the active and passive piles was the most susceptible to be affected by the leading passive pile within this zone the larger magnitude of ground heave by up to 50 was caused by the leading passive pile the leading passive pile also enhanced the lateral resistance of the active pile by up to 70 the underlying reason is that the leading passive pile was located in the passive influence zone of the active pile and hence restrained the intermediate soil between the two piles as a result the relative stiffness ratio between soil and pile increased leading to a stronger soil resistance

experimental determination of the diffusion rate of deuterated water vapor in ice and application to the stable isotopes smoothing of ice cores abstract the stable isotope records of d and 18o in ice cores show that the isotopic gradients are smoothed out with time by diffusion transport of hydrogen and oxygen atoms through solid ice is slow whereas water vapor diffusion through the interconnected porosity is much faster smoothing occurs preferentially in the upper layers of firn where the density is lowest and is responsible for the gradual alteration of the isotopic stratigraphy results for the diffusion of water vapor in ice are presented they were obtained from laboratory experiments with diffusion couples prepared using artificial snow with different d h values the samples were allowed to diffuse for about one year at a controlled temperature before being cut into thin sections and analyzed with a mass spectrometer the effects of both temperature and density were investigated the measured diffusion coefficients are fully consistent with water vapor diffusion through the ice porosity the computed values are less than the diffusion coefficient of hdo in free air and imply a tortuosity factor in the range 3 2 6 5 depending on the sample density the influence of the grain sizes on the timescale of the isotopic homogenization between the vapor phase and the ice matrix was studied we show that for grain sizes up to 1 mm in diameter solid diffusion within the grains is not a limiting factor and therefore the isotopic equilibrium between the vapor and the solid phases can be considered as immediate the diffusion model developed to compute the diffusion coefficients was further applied to investigate the real case of isotope smoothing in ice cores the smoothing rate is highly dependent on the wavelength of the isotopic signal linked to the accumulation rate and on temperature finally the model was applied to tritium deposition in antarctica from a continuous record of artificial fallout at the south pole 1954 1978 the result shows that in spite of large gradients the initial distribution underwent only limited smoothing that did not exceed 10

fault creep along the southern san andreas from interferometric synthetic aperture radar permanent scatterers and stacking 1 interferometric synthetic aperture radar insar provides a practical means of mapping creep along major strike slip faults the small amplitude of the creep signal 10 mm yr combined with its short wavelength makes it difficult to extract from long time span interferograms especially in agricultural or heavily vegetated areas we utilize two approaches to extract the fault creep signal from 37 ers sar images along the southern san andreas fault first amplitude stacking is utilized to identify permanent scatterers which are then used to weight the interferogram prior to spatial filtering this weighting improves correlation and also provides a mask for poorly correlated areas second the unwrapped phase is stacked to reduce tropospheric and other short wavelength noise this combined processing enables us to recover the near field 200 m slip signal across the fault due to shallow creep displacement maps from 60 interferograms reveal a diffuse secular strain buildup punctuated by localized interseismic creep of 4 6 mm yr line of sight los 12 18 mm yr horizontal with the exception of durmid hill this entire segment of the southern san andreas experienced right lateral triggered slip of up to 10 cm during the 3 5 year period spanning the 1992 landers earthquake the deformation change following the 1999 hector mine earthquake was much smaller 1 cm and broader than for the landers event profiles across the fault during the interseismic phase show peak to trough amplitude ranging from 15 to 25 mm yr horizontal component and the minimum misfit models show a range of creeping locking depth values that fit the data

growth stratal architectures associated to decollement folds and fault propagation folds inferences on fold kinematics abstract in many thrust and fold belts asymmetric folds with overturned or steeply dipping forelimbs and gently dipping backlimbs are commonly interpreted as thrust related folds determining the folding mechanism exclusively from the final fold geometry in the pre growth units is possible only for a limited suite of structures the nature of fold thrust interaction in shallow structures can be inferred by coupling the fold geometric analysis with the study of the syntectonic sediment stratal architectures several factors such as axial surface activity fold uplift limb rotation and limb widening rates together with sedimentation and erosion rates control growth strata patterns because the evolutionary path of most of these parameters depends on the folding kinematics different growth stratal architectures are expected for different thrust related anticlines in this paper we examine the influence of the above factors on growth stratal geometries associated to a simple kink band and then we apply the same approach to kinematic models of decollement folding and fault propagation folding four geometric approaches are used to account for the geometry and kinematics of anticlines located at the tip of a blind thrust fault propagation folding with no excess layer parallel shear fault propagation folding with progressive layer parallel shear constant limb length decollement folding and variable limb length decollement folding whereas fault propagation folding with no excess layer parallel shear is a self similar folding mechanism the other three types involve limb rotation coherent geometries between growth and pre growth sequences develop at high sedimentation rates in the crest of fault propagation folds and incoherent ones in decollement folds minor differences within growth strata patterns occur at low sedimentation rates and when erosion affects the crest of the anticlines

assessment of the influencing factors on subsidence at abandoned coal mines in south korea this study deals with the characteristics of subsidence and the relationships between the subsidence factors over abandoned coal mines in south korea the subsidence factors that were investigated were the dip angle and thickness of the coal bed mining depth depth of subsidence and subsidence area in 548 cases of subsidence that occurred throughout the country a close relationship between the type of subsidence and mining method was identified there was an intimate relation between the depth of subsidence and the dip angle of the coal bed while the subsidence area proved to be in proportion to the thickness of the coal bed and mining depth and was in inverse proportion to the dip angle of the coal bed

2 d and 3 d modeling of detachment folds with hinterland inflation a natural example from the monterrey salient northeastern mexico abstract geologists now recognize the presence and abundance of detachment folds in various contractional settings several two dimensional geometric and kinematic models exist to describe the development of such structures these models typically are area balanced are interpreted to develop by hinge migration limb rotation or a combination of the two processes and possess a constant regional level outside the fold itself we present two new two dimensional geometric and kinematic models for detachment folds that incorporate hinge migration and limb rotation as their deformation mechanisms these area balanced models differ from previous models however in that they allow hinterland inflation to occur thereby creating a higher local regional level in the hinterland relative to the foreland this local regional difference across the detachment fold may reflect hinterland uplift due to thickening of the incompetent unit foreland deflation of the incompetent unit as material migrates into the fold core during fold growth and or migration of material out of the fold core as the fold tightens we illustrate the utility of these models by constructing pseudo three dimensional representations of the western termination of the nuncios fold complex in the monterrey salient northeastern mexico our results suggest that the limb rotation model more accurately portrays the overall three dimensional fold geometry for the nuncios fold complex matches the observed hinterland inflation and predicts more reasonable detachment depths for the structure along its length these results agree with interpreted kinematics based on field observations and illustrate how this modeling approach may help constrain interpretations of detachment folds with hinterland inflation in areas lacking sufficient data

isotopic diffusion in cold snow and firn molecular mixing in cold snow and firn is ordinarily controlled by vapor diffusion diffusion through or along the ice matrix is slow whereas diffusion from the air to within separate grains is comparatively rapid thus mixing occurs in the vapor phase and exchange with the local ice involves all the water molecules a quantification of these concepts is applied to the diffusion of oxygen isotopic depth profiles in southern greenland and at dome c antarctica it successfully describes the smoothing of measured profiles the smoothing rate is strongly dependent on temperature and density of the firn

detachment folds with fixed hinges and variable detachment depth northeastern brooks range alaska abstract detachment anticlines in the northeastern brooks range accommodated displacement above a detachment by buckling of a competent unit over an incompetent unit meso and microstructures in hinges and a lack of relict hinge structures in limbs suggest that these folds grew with fixed hinges the structural thickness of the incompetent unit beneath the folds detachment depth varies from less than to greater than the stratigraphic thickness a model in which incompetent unit thickness varies with fold area better approximates the geometry of the folds than does a more conventional constant depth model additional discrepancies between modelled and observed incompetent unit thickness and field observations suggest non plane strain and or transport of material through the boundaries of the fold in the plane of the cross section the results of this study suggest a typical evolutionary sequence for detachment folds in the northeastern brooks range which may be applicable elsewhere anticlines initiate as fixed hinge buckle folds rapid initial increase in anticlinal cross sectional area results in a decrease in incompetent unit thickness fold area begins to decrease with tightening beyond an interlimb angle of 90 dg decreasing fold area is accommodated through some combination of structural thickening of the incompetent unit transport of solid or dissolved material out of the plane of section transport of material through the boundaries of the fold in the plane of the cross section and or truncation by thrust faults

controlled experiments on the diffusion rate of stable isotopes of water in artificial firn we studied the diffusion rate of stable isotopes of water ice in a controlled laboratory experiment where isotopically different layers of fabricated firn were stacked this experiment was done in order to study the diffusion rate between the isotopically different layers and to compare the measurements with forward calculated diffusion rates of the fabricated firn stack using three different analytical and numerical methods the layers varied in thickness within the stack and the studied period includes variations in firn temperature we sampled the firn stack on five different dates along the 144 day long experiment we obtained a quantitatively good match between the calculated and measured diffusion rates with a root mean square similarity of 67 80 in the depth averaged diffusion rates despite the good average match we found some qualitative discrepancy between our calculations and our measurements the calculated diffusion rates predict 5 faster isotopic decay of thinner layers and 13 slower decay of thicker layers than our measurements show we speculate that grain size and grain fabric may influence the tortuosity of the firn pack and that the current generalization of tortuosity being a function of firn density as the only free parameter is an oversimplification

multiyear accumulation and temperature history near the north greenland ice core project site north central greenland this paper presents a comparison of two independent methods of estimating subseasonal accumulation across the interior of greenland these methods high resolution snow pit studies and atmospheric modeling have differing spatial and temporal resolution but both can estimate net accumulation for subseasonal and shorter periods the snow pit approach is based on a documented relationship between high resolution snow pit profiles of oxygen stable isotope ratio 18o and multiyear special sensor microwave imager ssm i 37 ghz brightness temperature records comparison of ssm i data to profiles obtained during the 1995 alfred wegener institut north greenland traverse field season shows that 18o data from snow in north central greenland are a reliable high resolution temperature proxy this enables determination of accumulation amount rate and timing from approximately july 1991 through june 1995 across this 220 km long transect of the ice sheet precipitation estimates derived from early modeling based on european centre for medium range weather forecasts data show a similar average seasonal pattern but a diminished magnitude of accumulation 56 for these sites the slope of the multiyear t versus correlation was evaluated for each site on the basis of the observed and calculated temperature history from the nearby north greenland ice core project ngrip site automatic weather station these data should assist interpretation of the paleoclimatic record in the ngrip deep core

reconstructing annual and seasonal climatic responses from volcanic events since a d 1270 as recorded in the deuterium signal from the greenland ice sheet project 2 ice core a 200 m ice core at the gisp 2 site summit greenland provides a 720 year record of volcanic eruptions identified by pronounced increases in so42 in relation to the background concentration deuterium hydrogen isotope ratios d measured in the same core provide a proxy climate record temperature used to examine the response of the climate system in greenland to these eruptions a group of 34 known volcanic events and a subgroup of the six largest volcanic events are isolated and examined for both groups significant negative cooler isotopic excursions occur beginning the year the volcanic event is detected in the ice core cooling is significant for 1 to 2 years the maximum isotopic excursion averages 4 0 7 c for all 34 events and 10 1 8 c for the subgroup of largest events for individual events the response in the isotope signal to volcanic events is highly variable but occurs at most 1 year before so42 is detected in the core examination of subannual isotope data suggests that peak winter isotope values are lowered more than peak summer values we hypothesize that this result is flawed by posted positional alteration of the isotopic profile by vapor diffusion to test this hypothesis we use numerical deconvolution to account for the smoothing effects of vapor diffusion in the firn analysis of the deconvolved data shows greater summer than winter cooling a result more consistent with instrumental temperature data

deflation of the askja volcanic system constraints on the deformation source from combined inversion of satellite radar interferograms and gps measurements the askja central volcano in northern iceland has been continuously subsiding at least since 1983 gps and optical leveling tilt measurements show subsidence of at least 75 cm from 1983 to 1998 in the center of the askja caldera without any eruptive activity we have performed an interferometric analysis of synthetic aperture radar images insar of the area utilizing data from the ers satellites we observe subsidence of the askja caldera and its fissure swarm up to a distance of 25 km from the volcano we evaluate the geometry of the magma chamber at askja from a combined inversion of satellite radar interferograms and gps measurements several models were tested including a mogi point source as well as an ellipsoidal source the use of an ellipsoidal source instead of a mogi source gives an estimate of the dimensions of the magma chamber and its deflating pressure whereas these parameters are not independently resolved if a mogi source is used two source models were also considered in order to explain the additional subsidence observed along the askja fissure swarm we tested a model using two mogi sources at different depths a shallow ellipsoidal cavity with a deeper mogi source and then a shallow mogi source with a deeper elongated ellipsoid oriented along the fissure swarm results indicate that an ellipsoidal source at about 3 km depth can accommodate most of the deflation occurring in the caldera residual subsidence occurs along the askja fissure swarm suggesting the existence of a deeper source of contraction we interpret this signal in terms of subsidence of the plate boundary

kink detachment fold in the southwest montana fold and thrust belt the hossfeldt anticline in the southwest montana thrust belt is characterized by a kink geometry and probably overlies a thrust detachment at depth the mesofabric distribution in the limbs documents that the eastern overturned limb has undergone most of the rotation and internal deformation during folding leaving the gently dipping western limb virtually undeformed the anticline exhibits unique mesofabrics in its hinge region that require a pinned anticlinal hinge during its evolution the half wavelength of the hossfeldt anticline eustis syncline pair coincides with that predicted from buckling theory if one considers the massive carbonates of the paleozoic section as a competent beam although the geometry and mesofabric distribution of the hossfeldt anticline satisfy the geometric requirements of either a fault propagation fold or a detachment kink fold the buckling wavelength strongly suggests that its origin was as a kink buckle fold above a flat detachment rather than as a fault propagation fold above a thrust ramp

excess area and depth to detachment a plot of the excess area in cross section vs the depth to a reference level for several stratigraphic horizons in a compressional fold produces a curve that gives the depth to detachment the curve is a straight line for detachment folds the slope of the line is the displacement on the lower detachment and the depth intercept where excess area zero is the depth to detachment for a fault bend fold the result is a line that abruptly changes slope at the position corresponding to the upper detachment the difference in slope between the two parts of the line is the displacement on the upper detachment added layer parallel shear produces a curve on the graph tested on detachment folds from the jura mountains the method accurately predicts the depth to detachment he tip top field anticline in the wyoming thrust belt is found to be interpretable as either a detachment anticline with a basal detachment close to the top of the basement or as a fault bend fold with a basal detachment at the base of the triassic the excess area diagram is useful for testing a cross section for balance determining the structural style detachment anticline vs fault bend fold and for examining alternatives in the construction of cross sections

accuracy and resolution of alos interferometry vector deformation maps of the father s day intrusion at kilauea we assess the spatial resolution and phase noise of interferograms made from l band advanced land observing satellite alos synthetic aperture radar sar data and compare these results with corresponding c band measurements from european space agency remote sensing satellite ers based on cross spectral analysis of phase gradients we find that the spatial resolution of alos interferograms is 1 3times better than ers interferograms the phase noise of alos i e line of sight precision in the 100 5000 m wavelength band is 1 6times worse than ers 3 3 mm versus 2 1 mm in both cases the largest source of error is tropospheric phase delay vector deformation maps associated with the june 17 2007 father s day intrusion along the east rift zone of the kilauea volcano were recovered using just four alos sar images from two look directions comparisons with deformation vectors from 19 continuous gps sites show rms line of site precision of 14 mm and rms azimuth precision flight direction of 71 mm this azimuth precision is at least 4times better than the corresponding measurements made at c band phase coherence is high even in heavily vegetated areas in agreement with previous results this improved coherence combined with similar or better accuracy and resolution suggests that l band alos will outperform c band ers in the recovery of slow crustal deformation

geometric constraints derived from the law of conservation of volume and applied to evolutionary models for detachment folding this paper presents geometric arguments for modifying the conventional concept for the evolution of concentric fold trains above nonductile detachment zones the common geometric model for concentric folding above a detachment invokes a wave train with fixed fold axes regularly spaced along the fold panel limb lengths from crest to trough remain constant as the limb dips increase to uplift the anticlinal crests while the synclinal troughs slide parallel to the detachment plane the basic depth to detachment calculation which derives from the law of conservation of volume requires that the area of uplift above regional for a concentric anticline be equal to the arithmetic product of the shortening and the depth to detachment this imposes a geometric constraint with which a constant limb length anticline growing by increasing limb dip above a fixed detachment plane cannot comply unless in the early stages mobile material in the detachment zone flows from the synclinal troughs to the anticlinal crests and then in the later stages the flow direction reverses relatively few detachment zones contain a significant amount of mobile salt or shale therefore in most concentric detachment fold trains a basic geometric incompatibility exists between the conventional geometric model and themore law of conservation of volume the conflict can be resolved by an evolutionary fold model wherein the anticlinal fold limbs are short at the inception of folding and grow longer as dips increase and the fold grows in this model the anticlinal axes generally are fixed and the synclinal axes active which has structural and economic implications for the distribution of permeability and syntectonic sediments as well as for the migration and entrapment of hydrocarbons 18 figs less

oxygen and hydrogen isotopic ratios of water in precipitation beyond paleothermometry paleoclimatologists face a dilemma no sedimentary proxy is a pure recorder of quantitative climate information yet climate modelers and policy makers increasingly seek quantitative comparisons between instrumentally documented possibly anthropogenic climate changes and those produced naturally in the past in the second edition of his influential book bradley 1999 p 6 discussed the calibration of proxy records to learn past climate changes calibration involves using modern climatic records and proxy materials to understand how and to what extent proxy materials are climate dependent it is assumed that the modern relationships observed have operated unchanged throughout the period of interest the principle of uniformitarianism in other words one relates the characteristics of sediment to climate at different places for one time or at a place for short times and then uses that relation plus characteristics of older sediments to estimate the climatic conditions that produced those sedimentary characteristics bradley 1999 then extensively discussed the difficulties in applying this methodology in a complex world with imperfect recorders nonetheless the goal of using calibrated proxies for quantitative as well as qualitative paleoclimatic reconstruction is clear a prominent recent use of calibrated paleoclimatic data is the assessment of whether the probably anthropogenic warming of the latter 20th century moved beyond the band of natural variability of the prevailing climate bradley 2000 combined recent instrumental records with several longer proxy based reconstructions of surface temperature including that of mann et al 1999 based on this composite data set bradley 2000 argued that temperatures in the late 20th century were unique in the context of the entire millennium the proxy records were primarily based on tree ring data but included isotopic and major element geochemistry of corals and occurrence of melt layers and isotopic ratios of water in ice cores however broecker 2001 questioned the basis for the reconstruction of

physically based modeling of atmosphere to snow to firn transfer of h2o2 at south pole quantitative interpretation of ice core chemical records requires a detailed understanding of the transfer processes that relate atmospheric concentrations to those in the snow firn and ice a unique 2 year set of year round surface snow samples at south pole and snow pits with associated accumulation histories were used to test a physically based model for atmosphere to firn transfer of h2o2 the model which extends our previous transfer modeling at south pole into the snowpack is based on the advection dispersion equation and spherical diffusion within representative snow grains required physical characteristics of the snowpack such as snow temperature and ventilation were estimated independently using established physical models the surface snow samples and related model simulations show that there is a repeatable annual cycle in h2o2 in the surface snow at south pole it peaks in early spring and surface snow concentration is primarily determined by atmospheric concentration and temperature with some dependence on grain size the snow pits and associated model simulations point out the importance of accumulation timing and annual accumulation rate in understanding the deposition and preservation of h2o2 and 18o at south pole long term snowpack simulations suggest that the firn continues to lose h2o2 to the atmosphere for at least 10 12 years 3 m after burial at current south pole temperatures and accumulation rates

a new method for measuring deformation on volcanoes and other natural terrains using insar persistent scatterers 1 we present here a new insar persistent scatterer ps method for analyzing episodic crustal deformation in non urban environments with application to volcanic settings our method for identifying ps pixels in a series of interferograms is based primarily on phase characteristics and finds low amplitude pixels with phase stability that are not identified by the existing amplitude based algorithm our method also uses the spatial correlation of the phases rather than a well defined phase history so that we can observe temporally variable processes e g volcanic deformation the algorithm involves removing the residual topographic component of flattened interferogram phase for each ps then unwrapping the ps phases both spatially and temporally our method finds scatterers with stable phase characteristics independent of amplitudes associated with man made objects and is applicable to areas where conventional insar fails due to complete decorrelation of the majority of scatterers yet a few stable scatterers are present

non climate influences on stable isotopes at taylor mouth antarctica the late holocene trends in 18 o differ significantly in two ice cores 30 km apart from the area of taylor dome antarctica it is unlikely that the trend in the core from taylor mouth the flank site is due to a standard 18 o surface temperature relationship assuming that the taylor dome near summit core records local climate variations common to both cores we assess two leading possible causes for the observed differences 1 relative to taylor dome taylor mouth may collect snow from more sources with distinct isotopic compositions 2 vapor motion during prolonged near surface exposure may cause post depositional isotope enrichment at taylor mouth where the accumulation rate is low our model of firn pore space vapor and sublimating ice grains suggests that post depositional processes can modify 18 o values by several o isotopic samples from areas with significantly different accumulation rates near taylor mouth could differentiate between possibilities 1 and 2

analysis of roof fall hazards and risk assessment for zonguldak coal basin underground mines the roof fall hazards are frequent problems of underground coal mines which are generally unpredictable due to the associated uncertainties these uncertainties which arise from geological and stress conditions and mine environment make the control of roof fall hazards difficult in underground coal mines the most efficient method for coping with uncertainties in roof fall hazards is the use of risk assessment techniques in this study a risk assessment and management methodology is proposed for roof fall hazards in underground mines of the zonguldak coal basin the annual rates of roof falls obtained from the five mines in the basin are statistically analyzed the components of risk which are the probability of roof fall and consequences of roof fall hazard are identified and quantified the probability of roof fall is computed by fitting a distribution function to the annual roof fall while the consequences of roof falls are quantified based on a cost model then a decision analysis methodology for evaluating the performance of possible alternative action to be taken in order to decrease the risk is developed the results show that the underground coal mines in the zonguldak coal basin have considerably high risk levels and hence require comprehensive risk management schemes

synthetic aperture radar interferometry observations of the m 6 0 orta earthquake of 6 june 2000 nw turkey reactivation of a listric fault we study the coseismic surface displacement field due to the orta earthquake of 6 june 2000 a moderate sized mw 6 0 oblique slip event that took place on a previously unknown fault located about 70 km north of the capital ankara turkey and about 35 km south of the north anatolian fault we use european space agency ers synthetic aperture radar sar data to generate high resolution maps of the surface displacements by a two pass differential sar interferometry method the surface displacement field reaching up to 15 cm line of sight subsidence is captured in several coseismic interferograms from descending orbits and is inverted to determine the source parameters of the earthquake using elastic dislocations on rectangular fault surfaces with a nonlinear minimization procedure based on simulating annealing algorithm modeling of the coseismic interferograms indicates that the earthquake was associated with a shallow 6 km left lateral oblique normal displacement that occurred on a north south striking eastward dipping listric fault trending at a high angle to the plate boundary right lateral strike slip north anatolian fault careful analyses of multiple interferograms together with the field observations allow us to infer the rupture geometry in fine detail modeling shows that coseismic slip occurs nearly only on the lower portion of the listric fault at a centroid depth of about 5 km but partially reaches to the surface along the surface trace of the dodurga fault in agreement with the field observations we show that in the absence of field observations additional measurements or multiple interferograms that capture the surface deformation from different look angles sar interferometry alone may not be sufficient to constrain earthquake rupture geometry if there is no clear surface faulting the results suggest that the dodurga fault developed most probably as a result of a restraining bend along the north anatolian fault and its left lateral kinematics is consistent with the stress regime that favors the right lateral north anatolian fault

polar firn densification and grain growth a 50 m firn core from dome c east antarctica was found to consist of coarse firn which comprised 90 to 95 of the core and fine firn coarse firn was characterized by large crystals with a vertical shape orientation near the surface connected to nearest neighbors by relatively large necks in a structure different from closest packing fine firn was of higher density and consisted of smaller more spherical crystals connected by relatively narrow necks in a more nearly closest packed configuration higher surface free energy in fine firn causes crystals and necks to grow more rapidly than in coarse firn however we find that coarse firn densifies more rapidly with time contrary to the predictions of unconfined sintering models load driven densification due to a power law creep mechanism is found to account for the larger coarse firn densification rate however if the exponent in the power law exceeds one then densification rates are predicted to increase with depth due to increasing load contrary to observed behavior we speculate that different mechanisms may control the densification process in fine and coarse firn

determination of underground mining induced displacements using gps observations in zonguldak kozlu hard coal basin abstract mining activities cause horizontal and vertical movements on the earth s surface as well as in underground which give rise to environmental economical judicial and urbanization problems these movements or displacements the results of collapsing vertical displacement swelling slope change bending and cracking are referred to as mining subsidence which depends on the depth and dimension of mined area production methods underground operating speed time and geological structure of area the mining subsidence eventually affects the development of cities and city life by causing damages and destruction on buildings and structures on the surface in order to study the displacements caused by on going mining activities city of zonguldak its town kozlu and its near surroundings are chosen since they constitute the center for hard coal basin in turkey for 160 years with a population of 300 000 and an area of 80 km2 this study details the results from a gps network conducted in the basin to determine the horizontal displacements on the surface created by the mining activities the displacement results obtained from this study have been found to range from 10 to 78 mm with 4 4 to 7 9 mm rmse values these results indicate that the surface of the basin is under these effects today

geometry and kinematics of single layer detachment folds detachment folds form above below or above and below bed parallel thrusts where thrust displacement is transferred into folding geometric and kinematic models are developed for individual single layer detachment folds formed above the tip line of a thrust we analyze three different detachment fold shapes kink bands chevron and box detachment folds and consider three principal detachment fold models 1 constant limb dip where the detachment fold grows by limb lengthening 2 constant limb length where the detachment fold grows by limb rotation and 3 variable limb length and variable limb dip where the detachment fold grows by both limb rotation and limb lengthening the allowance for variable forelimb thickness and excess layer parallel shear enables us to de elop a wide range of possible detachment fold geometry the geometric validity fields for folds with excess parallel shear are reduced when forelimb thinning takes place folds formed with constant limb length are likely to lock up in the initial amplification stages whereas larger amounts of shortening can be taken up by folds formed with variable limb length the manner in which a fold evolves affects the fracture and porosity features of the folded strata therefore determining which mechanism operated to form a specific detachment fold is of particular importance in hydrocarbon exploration the models we present are aimed at permitting more accurate geometric and kinematic interpretations of individual detachment folds examples of detachment folds are analyzed to illustrate the po ential benefits and limitations of the geometric model presented

theory of metamorphism of dry snow the growth of ice particles in dry seasonal snow is caused by vapor diffusion among particles due to temperature gradients imposed on the snow cover the diffusion is calculated by using the potential field solutions for electrostatically charged particles the stereography of snow is represented by using a log normal distribution function for a geometrical enhancement factor defined here reasonable crystal growth rates and supersaturations are found the transition between the growth of highly faceted crystals and the growth of highly rounded crystals is determined by the critical supersaturation for the onset of dislocation aided growth thermal convection and the continuous movement of vapor around the particles due to the imposed temperature gradient are accommodated in the theory although both have little effect relative to the interparticle diffusion the growth of a layer of faceted crystals just below semi permeable crusts is explained by showing that crusts can cause the local supersaturation to exceed the critical value faceted crystals are shown to grow most rapidly in the lower warmer portions of the snow cover because of temperature effects on growth rate

water isotope diffusion in the wais divide ice core during the holocene and last glacial we use a high resolution water isotope record from the west antarctic ice sheet divide ice core wdc to evaluate the effects of water isotope diffusion for the last 29 ka b p using spectral analysis of the data we determine diffusion lengths in depth and time domains the diffusion length quantifies the mean cumulative diffusive displacement of water molecules relative to their original location at time of deposition we simulate the observed signal with models and find that our understanding of processes and conditions in the ice sheet is incomplete with the effects of ice deformational thinning removed portions of the holocene record show total diffusion lengths smaller than predicted for a lower limit case of diffusion through a single ice crystal such reduced diffusion is probably due to structural features such as crusts and tortuous porosity that inhibit vapor transport in the firn in the late glacial portion of the record diffusion lengths double between 19 5 and 17 ka b p known dependencies of diffusion on climatic variables do not account for this enhancement in models and we hypothesize that it could arise from thermal gradients in the firn column impurity driven enhancement of solid ice diffusion or changes in firn grain properties that alter vapor access to open pores despite model uncertainties the wdc diffusion length chronology will be an essential input to future studies of high frequency variability in the water isotope climate record as it allows for the effects of diffusion to be removed

oxygen 18 16 variability in greenland snow and ice with 10 3 to 105 year time resolution the 3 km long greenland ice sheet project 2 gisp2 ice core presents a 100 000 year detailed oxygen isotope profile covering almost a full glacial interglacial cycle measuranents of isotopic fluctuations in snow frost and atmospheric water vapor samples collected during summer field seasons up to 20 0 are compatible with the large and abrupt 80 160 changes observed in accumulated tim snow pit 15 80 profiles from the gisp2 summit area however show rapid smoothing of the 180 160 signal near the surface beyond about 2 m depth the smoothedi5180 signal is fairly well preserved and can be interpreted in terms of average local weather conditions and climate the longer climate fluctuations also have regional and often global significance in the older part of the record corresponding to marine isotope stages mis 5a to 5d the effect of orbital climate forcing via the 19 and 23 kyr precession cycles and the 41 kyr obliquity cycle is obvious from the end ofmis 5a at about 75 000 years b p till the end of the glacial at the younger dryas preboreal transition at 11 650 years b p the o180 160 record shows frequent rapid switches between intermediate interstadial and low stadial values fourier spectra of the oscillations that are superimposed on the orbitally induced changes contain a strong periodicity at 1 5 kyr a broad peak at 4 0 kyr and additional shorter periods detailed comparison of the gisp2 180 160 record with the vostok antarctica 15d record pacific ocean foraminiferal 180 160 grande pile france tree pollen and insolation indicates that a counterpart to many of the rapid 180 160 fluctuations of gisp2 can be found in the other records and that the gisp2 isotopic changes clearly are the local expression of climate changes of worldwide extent correlation of events on the independent gisp2 and specmap time scales for the interval 10 000 50 000 years b p shows excellent chronometric agreement except possibly for the event labeled 3 1 the glacial to interglacial transition evidently started simultaneously in the arctic and the antarctic but its development and its expression in greenland isotopes was later suppressed by the influence of meltwater especially from the barents sea ice sheet on deep water formation and ocean circulation meltwaters from different ice sheets bordering the north atlantic also influenced ocean circulation during the bolling allerod interstadial complex and the younger dryas and led to a distinct development of european climate and greenland 180 160 values the holocene interval with long term stable mean isotopic values contains several fluauations with periods from years to millennia dominant is a 6 3 year oscillation with amplitude up to 3 to 4 0 periodicities of 11 and 210 years also found in the solar modulated records of the cosmogenic isotopes 1obe and 14c suggest solar processes as the cause of these cycles depression of180 160 values cooling by volcanic eruptions is observed in stacked gisp215 80 records but the effect is small and not likely to trigger major climate changes

spatio temporal analysis of ground subsidence due to underground coal mining in huainan coalfield china underground coal mining produces ground subsidence that adversely impacts the environment huainan coalfield one of the largest coalfields in east china experiences fast ground subsidence that restricts agricultural urban and rural developments in this region we used stacking and the small baseline subset interferometric synthetic aperture radar insar techniques to perform a spatio temporal analysis of ground subsidence in huainan coalfield caused by underground coal mining activities fourteen l band alos palsar images acquired during 2007 2010 were used to retrieve high resolution and high precision time series of ground deformation and the mean deformation rate the results show that subsidence with a rate of up to 15 cm year is widely spread over the studied area in response to mining operation in regions where mining lasted for many years ground subsidence continues at a steady rate during the entire observation period in regions of recent i e since 2007 2009 mining activities ground subsidence is rapidly accelerating accumulated subsidence already caused submerging of the agriculture lands limiting further mining activities and farming the insar results are consistent with the ground leveling measurements and observations it is confirmed that the l band insar can be successfully utilized for mapping long term subsidence in huainan coalfield in china caused by underground coal mining activities

extreme snow metamorphism in the allan hills antarctica as an analogue for glacial conditions with implications for stable isotope composition understanding physical processes in near zero accumulation areas can help us to better understand polar ice core records particularly during periods when accumulation rates were lower than today we report measurements from a 5 m firn core from the allan hills antarctica which include physical properties using computer tomography stable isotope ratios d and 18 o and 210 pb activity the core shows a highly metamorphosed firn with homogeneous and stable structure but with discrete layers near the surface the observed firn structure is caused by a combination of unique depositional and post depositional processes the irregular d and 18 o signal does not follow the stratigraphic sequence and implies post depositional modification caused by microscopic pressure gradients in the firn that can result from either forced ventilation over rough surfaces in the presence of wind or alternating temperature gradients between the firn and the atmosphere our results also indicate impact snow deposition under high winds and with a high initial density and air exchange between the atmosphere and the snowpack 210 pb activity below 0 3 m falls below the detection limit implying that most of the core is more than 100 years old we conclude that the allan hills record provides a unique opportunity to investigate important processes that would have affected ice core records from glacial periods

effects of mining subsidence on masonry buildings in zonguldak hard coal region in turkey gallerias are the underground constructed results of mining as these space in underground layers collapse horizontal and vertical ground movements occur and movement which may reach the earth s surface are known as mining subsidence the result of underground displacement may cause surface ground movement which can be detrimental to masonry buildings especially in hard coal regions thorough familiarity with general and regional characteristics of an affected area can assist reduction of the effects zonguldak and the nearby settlement area with a population of 300 000 constitute the centre of a hard coal basin where extensive mining has a history extending through 160 years mining constitutes the main economic activity in this region and consequently influences every aspect of life this study s intent is to identify the effects of mining subsidence on masonry buildings in the mining area of kozlu zonguldak turkey and illustrate them with selected images of damaged masonry buildings also included are satellite and mining galleria images

evidence for an early holocene climatic optimum in the antarctic deep ice core record in the interpretation of the antarctic deep ice core data little attention has been given to the holocene part of the records as far as translation of the stable isotope content in terms of temperature is concerned this can be understood because expected temperature changes may be obscured by isotopic noise of various origins and because no 14c dating has yet been available for this type of sequence in this article we focus on the dome c and vostok cores and on a new 850 m long ice core drilled out at komsomolskaia by the soviet antarctic expeditions these three sites are located in east antarctica on the antarctic plateau in a region essentially undisturbed by ice flow conditions so that their detailed intercomparison may allow us to identify the climatically significant isotopic signal our results compare well with the proximal records of southern hemisphere high latitudes and support the existence of a warmer climatic optimum between 10 and 6 ka y bp maximum temperatures are reached just at the end of the last deglaciation which confirms previous observations at high latitudes in contrast with later dates for the atlantic and hypsithermal optima in europe and north america

holocene temperature variations inferred from antarctic ice cores we have reconstructed temperature changes over the past 15 000 years from ice core data in antarctica we used measurements of the d h isotope ratio in ice as a proxy of temperature for central sites vostok dome c and komsomolskaya as well as coastal sites d47 d15 and d10 first we examined the dating of each core and built up a common temporal framework for the ensemble of the data secondly we addressed the problem of inferring small amplitude temperature fluctuations from the isotope data in the light of noise generating mechanisms involved in snow deposition temperature was reconstructed so as to minimize distortion created by the sampling of ice cores in the field the seven ice cores studied yield an average temperature curve which can be put in perspective with nearby paleoclimatic records the early holocene experienced climates warmer than today by 1 2 c the late holocene period shows more discernible shorter duration temperature fluctuations superimposed on a fairly stable base line temperature

geometric and numerical model of progressive limb rotation in detachment folds a simple area balanced geometric model of progressive limb rotation in detachment folds allows the quantification of displacement uplift and rotation and the assessment of their effect upon growth strata geometries translation of this geometric model into a velocity model of deformation allows the modeling of associated growth strata resulting from background sedimentation and local erosion transport and deposition we show that with constant displacement and sedimentation rate this model predicts a progressive unconformity indicating the onlap and eventual overlap of the fold limb caused by a decreasing uplift rate this decrease is a consequence of the kinematics of progressive limb rotation increases in displacement rate with sedimentation rate kept constant can lead to offlap and angular unconformities although subsequent onlap does not necessarily reflect a return to a lower displacement rate modeled growth strata geometries exhibit many of the features reported from the literature

post depositional modification of stable water isotopes in winter snowpacks in the canadian rocky mountains to assess the seasonal stability of the do stratigraphy in winter snowpacks in the canadian rocky mountains snow pits were sampled over three accumulation seasons at two field sites these sites opabin and haig glaciers are 160 km apart at similar elevations and represent windward and lee slope environments respectively at both sites snow pits were sampled at one glacier and one forefield location throughout each accumulation season intra seasonal changes in do at each site were examined to determine the extent of post depositional modification of isotope stratigraphies at both glacier sites there was minimal temporal change before the onset of spring melt in all years in addition the similar structure of do profiles from both glacier sites suggests that regional controls govern the isotopic composition of solid phase precipitation across the study area at forefield locations the absence of an insulating layer of ice at the base of the snowpack allowed for vapour transport and post depositional modification of the seasonal do signal this did not result in consistent changes to the mean do deuterium excess and dd do regression line slopes in the lower layers of snow and the observed smoothing of do profiles was less than that simulated by applying a diffusion model to these snowpacks

densification of water ice deposits on the residual north polar cap of mars abstract understanding the density evolution of any ice deposits on the martian north polar residual cap is key to understanding whether the cap contains a climate record in the form of occluded samples of past atmospheres we present a physical model for densification of water ice deposits on the cap due to gravity driven sintering and temperature gradient driven vapor transport the model predicts the steady state profile of porosity versus depth in the ice cap for specified time independent mass accumulation rate and surface deposition density and for surface temperatures with specified diurnal and seasonal variations that comprise an invariant annual cycle we find that in contrast to the analogous situation on earth vapor transport dominates densification in the current martian climate this mechanism can produce very low porosity near surface ice even when accumulation rates are small but positive comparable to those presently thought to occur thus recent inferences of high thermal inertia on the cap may not necessarily imply that the cap is ablating the model predicts a sharp transition between temperature and accumulation conditions under which a deep firn column results and those characterized by very low surface porosity finally we derive a temporal frequency dependent thermal inertia for a vertically inhomogeneous medium observations of this quantity are at least in principle useful for remote estimation of the ice cap density variations within about 10 m of the surface

temperature history and accumulation timing for the snowpack at gisp2 central greenland previous research has documented a close association between high resolution snow pit profiles of hydrogen and oxygen stable isotope ratios and multi year special sensor microwave imager ssm i 37 ghz brightness temperature data in central greenland comparison of the ssm i data to profiles obtained during the 1989 91 field seasons indicated that d and 18 o data from the near surface snow at the greenland summit are a reliable high resolution temperature proxy to test this new technique further additional stable isotope data were obtained from a 2 m snow pit constructed during late june 1995 near the gisp2 site this new profile supported by pit stratigraphy and chemistry data confirms the utility ofcomparing stable isotope records with ssm i brightness temperatures the sub annual variation of the d record at the gisp2 site was determined using 15 match points from approximately december 1991 through june 1995 and was guided in part by time constrained hoar layers the close association of these temperature proxies supports the assertion that snow accumulation occurs frequently through the year and that the isotope record initially contains temperature information from many times of the year this is also independently confirmed by analysis of h 2 o 2 data the slope of the multi year t vs 6 correlation was evaluated along with the sub annual variation in the amount rate and timing of accumulation these new results are consistent with those from the previous study and they also demonstrate that the snow in this area initially contains temperature and chemical records with sub annual resolution this encourages confident interpretation of the paleoclimatic signal variations in the gisp2 and grip deep cores

conditions for bubble elongation in cold ice sheet ice highly elongated bubbles are sometimes observed in ice sheet ice elongation is favored by rapid ice deformation and opposed by diffusive processes we use simple models to show that vapor transport dominates diffusion except possibly very close to the melting point and that latent heat effects are insignificant elongation is favored by larger bubbles at pore close off but is nearly independent of bubble compression below close off the simple presence of highly elongated bubbles indicates only that a critical ice strain rate has been exceeded for significant time and provides no information on possible disruption of stratigraphic continuity by ice deformation

insar derived digital elevation models for terrain change analysis of earthquake triggered flow like landslides based on alos palsar imagery earthquakes can directly trigger multiple simultaneous slope failures in mountainous regions among these slope failures flow like landslides with high velocities and long run outs can result in damage that is more destructive than other types of landslides timely and accurate recognition of the locations and magnitudes of flow like landslides is essential for post disaster relief synthetic aperture radar sar sensors are suitable for deformation monitoring because of their capability to operate at day or night and in all weather conditions interferometric synthetic aperture radar insar is an advanced technique that extracts three dimensional terrain and changes information from the radar images at a regional scale the focus of this study is the donghekou landslide debris flow that was triggered by the 2008 wenchuan earthquake alos palsar remote satellite images were interpreted by insar to generate digital surface elevation models a comparison of data from a typical insar configuration with field survey data proves that the former is an effective method for rapidly detecting flow like landslides in a mountainous area the comparison also shows that the accuracy of the results is closely related to the correlation between the satellite radar images used and further that the study accuracy would improve with the inclusion of better correlation in this way representations of pre and post landslide terrains could be generated for use in numerical simulations the insar method has particular significance for areas without terrain data prior to slope failure and can provide basic data for landslide hazard assessments

assessment of geo environmental problems of the zonguldak province nw turkey the zonguldak province is a coastal settlement area that has been suffering from serious natural and human induced environmental problems sourced by its geology and geomorphology since the province locates at the heart of a coal producing basin the geo environmental problems related to mining activities such as esthetic degradation disposal of mining wastes and subsidence of the abandoned coal galleries are badly affecting every day life in zonguldak province disposal of municipal wastes is also a big problem since only one municipality out of 32 has a sanitary disposal area the rest of the municipalities dispose their solid wastes to rivers or to the sea the province has also some health problems which are pointed out in the literature related to coal mining and geologic environment these are cytogenetic damage in peripheral lymphocytes and pheumoconiosis most commonly seen at coal workers goiter and cancer landslides are the most important hazards in the area since 13 of the total surface of the zonguldak is affected by landslides in this study considering the hazard potential special attention is given to deep landslides and using the stepwise forward conditional logistic regression technique the landslide susceptibility map for the zonguldak province is produced the results showed that the most important independent variables governing the landslides are slope gradient volcanic and sedimentary rocks of eocene and clastic and carbonate units of cretaceous the landslide map is used as a base map for the production of geo hazard reconnaissance map on which areas subjected to other important geo hazards flood earthquake and subsidence are also shown to provide guidance for both existing settlement areas to take the necessary preventive measures and for new developing settlement areas to avoid the problematic areas

southern hemisphere climate variability forced by northern hemisphere ice sheet topography an antarctic ice core reveals that during the last ice age the topography of northern hemisphere ice sheets shifted tropical pacific convection eastward increasing climate variability in the high southern latitudes during glacial maxima ice covered vast areas of the northern hemisphere and had a broad influence across the global climate system tyler jones and colleagues show that climate variability in the southern hemisphere was influenced by these large northern hemisphere ice sheets and was about twice as high during the last glacial maximum than in the warmer holocene that followed the ice sheets created more elevated and brighter surfaces than at present and this altered the location of tropical convection and the atmospheric pathways that link the tropics to west antarctica the results reveal the intimate climatic link between the high latitudes and the key role of the tropics as an interhemispheric mediator the presence of large northern hemisphere ice sheets and reduced greenhouse gas concentrations during the last glacial maximum fundamentally altered global ocean atmosphere climate dynamics1 model simulations and palaeoclimate records suggest that glacial boundary conditions affected the el nino southern oscillation2 3 a dominant source of short term global climate variability yet little is known about changes in short term climate variability at mid to high latitudes here we use a high resolution water isotope record from west antarctica to demonstrate that interannual to decadal climate variability at high southern latitudes was almost twice as large at the last glacial maximum as during the ensuing holocene epoch the past 11 700 years climate model simulations indicate that this increased variability reflects an increase in the teleconnection strength between the tropical pacific and west antarctica owing to a shift in the mean location of tropical convection this shift in turn can be attributed to the influence of topography and albedo of the north american ice sheets on atmospheric circulation as the planet deglaciated the largest and most abrupt decline in teleconnection strength occurred between approximately 16 000 years and 15 000 years ago followed by a slower decline into the early holocene

reverse modelling of detachment folds application to the pico del aguila anticline in the south central pyrenees spain abstract a simple method to estimate fold amplification and thrust movement rates for detachment folds is documented and illustrated by its application to a symmetrical detachment fold in the southern pyrenees spain the technique provides a complete record of the kinematic evolution of detachment folds and is based on the application of equations for detachment folds involving limb rotation the method uses the stratal pattern of the syntectonic sediments and assumes that these growth strata were deposited horizontally that the folds involve a homogeneous competent unit detached over a ductile horizon and that the folds can be represented by chevronkink bands the procedure is applicable to any detachment fold with associated growth strata that display wedge geometries progressive unconformities indicating limb rotation through time this method can be used for both detachment folds formed with constant limb length or variable limb length and it can also accommodate undecompacted or decompacted growth strata

the origin of present day antarctic precipitation from surface snow deuterium excess data the deuterium excess d is defined as a linear combination of the d h and 18 o 16 o ratios in natural waters we present an interpretation of deuterium excess data in surface antarctic snow using an isotopic model to derive information on the origin of present day antarctic precipitation the data come from near the coast d47 adelie land and from inland south pole 1000 km from the sea the one dimensional isotopic model belongs to the rayleigh family but fully accounts for mixed cloud processes between 0 c and 30 c modeling d in polar snowfalls meets the problem of a large sensitivity to the saturation conditions prevailing at snow formation therefore we decided to tune the saturation in the model in order to yield realistic mean d values but we use the seasonal phase of d versus which is less sensitive to the saturation conditions as an independent validation of the model predictions both inland and near the coast our model can simulate the observed phase between d and in snow with moisture of subtropical origin 40 20 s although we do not treat specifically storm precipitation near the coast this study indicates that the observed phase between d and brings up a new validation of isotopic models it supports a distant vapor source for large scale precipitation delivered to the antarctic continent

monitoring of post failure landslide deformation by the ps insar technique at lubietova in central slovakia interferometric synthetic aperture radar data from ers and envisat sensors were utilized in the analysis of the post failure deformations in the area of lubietova town in central slovakia the catastrophic landslide of 1977 together with surrounding landslides in the lubietova area were analysed with the help of persistent scatterers ps technique in order to evaluate recent and past deformations of the unstable slopes although long term precise geodetic monitoring of the 1977 landslide revealed differential deformations inside the sliding mass due to the lack of the ps located inside the landside caused by temporal decorrelation unfortunately these records could not be directly compared the adjacent landslides with sufficient number of ps were analysed by transformation of the line of sight displacements recorded by the sensors to the slope vector direction this procedure allowed identification of the precise boundaries of the actively moving landslide parts and the updating of the landslide inventory for the lubietova area

reconstruction of the undiffused seasonal oxygen isotope signal in central greenland ice cores the climatologically important seasonal signal in ice core oxygen isotope records is altered by diffusion with time here we use the diffusion model of whillans and grootes 1985 to calculate the effects of isotopic diffusion in nine shallow ice cores recovered over a 150 150 km grid centered on summit greenland two different computational methods give similar results for the back diffused 18o seasonal extrema although back diffusing the ice core 18o records improves the correlations between the individual ice core oxygen isotope and greenland coastal temperature records the correlations remain poor particularly for the low accumulation sites stacking the back diffused isotopic records from several cores results in much higher correlations with a strong winter linkage between west coast stations and central greenland these correlations are also significantly greater than the correlations between the stacked measured diffused isotopic profiles and coastal temperatures our results indicate that the use of ice core isotopic records to identify anomalous seasons requires that diffusion effects be accounted for

isotopic diffusion in polar firn implications for interpretation of seasonal climate parameters in ice core records with emphasis on central greenland if it were possible to properly extract seasonal information from ice core isotopic records paleoclimate researchers could retrieve a wealth of new information concerning the nature of climate changes and the meaning of trends observed in ice core proxy records it is widely recognized however that the diffusional smoothing of the seasonal record makes a proper extraction very difficult in this paper we examine the extent to which seasonal information specifically the amplitude and shape of the seasonal cycle is irrecoverably destroyed by diffusion in the firn first we show that isotopic diffusion firn is reasonably well understood we do this by showing that a slightly modified version of the whillans and grootes 1985 theory makes a tenable a priori prediction of the decay of seasonal isotopic amplitudes with depth at the gisp2 site though a small adjustment to one parameter significantly improves the prediction further we calculate the amplitude decay at various other ice core sites and show that these predictions compare favorably with published data from south pole and locations in southern and central greenland and the antarctic peninsula we then present numerical experiments wherein synthetic ice core records are created diffused sampled reconstituted and compared to the original these show that alter diffusive mixing in the entire fini column seasonal amplitudes can be reconstructed to within about 20 error in central greenland but that all information about sub annual signals is permanently lost there furthermore most of the error in the amplitude reconstructions is due to the unknowable variations in the sub annual signal finally we explore how these results can be applied to other locations and suggest that dye 3 has a high potential for meaningful seasonal reconstructions while siple dome has no potential at all an optimal ice core site for seasonal reconstructions has a high accumulation rate and a low temperature

atmospheric circulation variability associated with shallow core seasonal isotopic extremes near summit greenland seasonal back diffused 18o time series reconstructed for nine shallow firn cores from the greenland summit for 1959 1987 are evaluated in terms of 1 their spatial and temporal variability and 2 their association to the atmospheric circulation rotated principal component analysis evaluates spatial and temporal patterns of organization in the back diffused 18o ice core time series mean sea level pressure and 500 hpa height fields are obtained for winter and summer seasons that fall in the isotopically warmest and coldest thirds of the seasonal data the winter back diffused 18o data indicate that some degree of longitudinal separation takes place between isotopic records from western and eastern greenland in agreement with coastal station climatic data temporal variability is linked with statistical significance to the variability of the atmospheric circulation over the denmark strait as well as over the norwegian and barents seas the north atlantic oscillation nao and the mean icelandic low in the denmark strait affect isotopic variability over the cores west of the ice divide just as they have been shown to prominently affect west coast air temperature records isotopic variability at some ice cores east of the divide is influenced by pressure variability over the norwegian and barents seas although statistical significance is lower the nao appears insignificant in summer isotopic variability as the circulation in that season is very much localized and dominated by either ridging warm cases or troughs cold cases over eastern greenland and the arctic ocean results suggest that long term winter 18o variability can potentially be linked to climate variation over europe especially from the mediterranean basin northward to about 55 n and as far east as central siberia

seasonal evolution of penitente glaciochemistry at tapado glacier northern chile this study uses stable isotopes and major ions to examine the seasonal evolution of penitentes on the surface of tapado glacier in the norte chico region of the chilean andes a snow pit was sampled in november 2011 and penitentes were sampled during the summer december 2011 and january 2012 the major ion load of the winter snowpack is dominated by ca2 60 so42 16 and no3 13 and there is little influence from marine air masses at the site with most so42 mg2 ca2 and na derived from non sea salt sources during the early ablation season we observe increases in stable isotope ratios and major ion concentrations particularly lithic ions na mg2 and ca2 in the upper reaches of penitentes which is attributed to sublimation and the aeolian deposition of dust particles in the late summer melt replaces sublimation as the dominant ablation process and results in smoothing of the stable isotope profile and the elution of major ions within the penitente snow and ice matrix copyright 2015 john wiley sons ltd