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

using cosmo skymed x band and envisat c band sar interferometry for landslides analysis abstract we explore new possibilities offered by the recently available x band satellite radar sensors for landslide hazard assessments on a detailed scale with particular reference to the exploitation of persistent scatterers interferometry psi techniques special attention is paid to the impact of the improved resolution of new x band radar imagery on the psi results in terms of quality and quantity of useful information this evaluation is supported by theoretical modelling as well as by the comparison of results from x band csk and c band envisat psi for two areas of interest one in italy and the other in switzerland it is demonstrated that with respect to medium resolution envisat ps processing fewer csk high resolution images are sufficient to achieve comparable precision of the mean displacement velocity estimates this together with the shorter revisit times provided by the csk constellation can be very important when dealing with emergency situations furthermore it is quantified that from about 3 to 11 times greater ps densities are obtained with the higher resolution x band data this implies more information about ground surface displacements as well as improved landslide monitoring and slope instability investigation capabilities furthermore ground displacement measurements can be interpreted without local knowledge of the focus area or in situ controls and nonetheless guide single hillslope instability assessments with support of google earth and its high resolution optical imagery this blind approach will allow one to monitor remote and poorly known regions at high risk of potentially disastrous slope failures

aeromagnetic identification and modeling of mafic ultramafic complexes in the huangshan turaergen ni cu metallogenic belt in nw china magmatic and metallogenic implications abstract aeromagnetic and bouguer gravity data are conducted to analyze the geological and metallogenic features of the huangshan turaergen ni cu polymetallic metallogenic belt in the gobi desert in northwest china the ni cu deposits are generally located to the south of the high amplitude gravity and magnetic gradient belt that marks the kanggurtag fault zone to analyze the prospecting potential of the complexes in the metallogenic belt the model depths and shapes of the complexes are calculated via euler deconvolution combined with three dimensional 3d inversion the buried complexes occur at relatively shallow depths and have ne orientations we use a method of lithology recognition based on 3d inversion modeling which enables the definition of two additional buried ultramafic complexes namely the west yaziquan wy and north yaziquan ny complexes our results reveal that these complexes have ring like shapes similar to most of the other known mafic ultramafic complexes in this metallogenic belt the upward continued bouguer gravity and aeromagnetic data reveal highly consistent gravity and magnetic anomalies which are explained as a regional magma chamber that is structurally controlled by the kanggurtag fault zone in order to determine the scale and shape of this regional magma chamber 3d gravity and magnetic inversion was carried out for the entire region according to models of the complexes and pluton the source driving mechanism and evolution of the regional magma are analyzed and the areas with mineralization and exploration potential are also discussed this work can aid in the exploration of additional ni cu deposits in eastern tianshan

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

geology and magmatic hydrothermal evolution of the giant pebble porphyry copper gold molybdenum deposit southwest alaska the pebble deposit is located 320 km southwest of anchorage alaska it is one of the largest porphyry deposits known with a total resource of 10 78 billion tons bt it comprises the east and west zones which are approximately equal in size with slightly lower grade mineralization in the center of the deposit where the peripheries of the two zones merge the west zone was discovered by cominco america in 1989 and the east zone was discovered by northern dynasty minerals in 2005 the oldest rock in the pebble district is the jurassic cretaceous kahiltna flysch unit which contains basinal turbidites interbedded basalt flows and associated gabbro intrusions these rocks were intruded between 99 and 96 ma by coeval granodiorite and diorite sills followed shortly thereafter by alkalic monzonite intrusions and related breccias subalkalic hornblende granodiorite porphyry plutons of the kaskanak batholith were emplaced at 90 ma similar smaller granodiorite plutons were emplaced around the margins of the batholith and are related to cu au mo mineralization re os dates on molybdenite are between 89 7 and 90 4 ma a late cretaceous volcanic and sedimentary cover sequence completely conceals the east zone whereas the west zone is overlain only by glacial sediments and is exposed in one small outcrop eocene volcanic rocks and subvolcanic intrusions occur east and southeast of the pebble deposit and unconsolidated glacial sediments are widespread the east and west zones represent two coeval hydrothermal centers within a single system the west zone extends from surface to 500 m depth and is centered on four small granodiorite plutons emplaced into flysch diorite and granodiorite sills and alkalic intrusions and breccias the much higher grade east zone extends to at least 1 700 m depth and is hosted by a larger granodiorite pluton and adjacent granodiorite sills and flysch the granodiorite plutons merge with depth on the east side of the deposit high grade mineralization has been dropped 600 to 900 m into the ne trending east graben where the deposit remains undelineated to the east and to depth variations in hypogene grade and metal ratios reflect multiple stages of metal introduction and redistribution hornfels related to the kaskanak batholith formed prior to hydrothermal activity at pebble and is most intensely developed in flysch disseminated and vein hosted cu au mo mineralization dominated by chalcopyrite and locally accompanied by bornite formed with potassic alteration in the shallow part of the east zone and with approximately coeval sodic potassic alteration in the west zone and at depth in the east zone illite kaolinite alteration overprinted potassic and sodic potassic alteration throughout the deposit and variably redistributed copper and gold high grade copper gold mineralization is related to advanced argillic alteration controlled by a synhydrothermal brittle ductile fault zone which overprinted potassic sodic potassic and illite kaolinite alteration in the east zone advanced argillic alteration comprises a core of pyrophyllite alteration associated with chalcopyrite bounded to the west by an upward flaring zone of sericite alteration which contains hypogene bornite digenite covellite and trace enargite and tennantite late quartz veins introduced additional molybdenum in several parts of the deposit grade destructive quartz sericite pyrite alteration forms a halo to the entire deposit and yields outward to propylitic alteration a quartz illite pyrite cap is preserved in the weakly mineralized center of the deposit mineralization at pebble is predominately hypogene a thin incompletely developed zone of supergene mineralization occurs in the west zone and is overlain by a thin leached capping there is no evidence for paleosupergene mineralization or leaching below the cover sequence in the east zone molybdenite contains high concentrations of rhenium throughout the deposit elevated palladium concentrations are associated with pyrophyllite alteration in the east zone the pebble deposit occurs in one of a number of large deep seated magnetic anomalies which are located at the intersection of crustal scale structures both parallel and at high angles to a mid cretaceous magmatic arc this setting is similar to fertile porphyry environments in northern chile and suggests that southwestern alaska is highly prospective for porphyry exploration the large size and high hypogene grades of the pebble deposit may reflect a combination of multiple stages of metal introduction with vertically restricted lateral fluid flow induced by hornfels aquitards in flysch

toward mapping surface deformation in three dimensions using insar 1 one of the limitations of deformation measurements made with interferometric synthetic aperture radar insar is that an interferogram only measures one component of the surface deformation in the satellite s line of sight we investigate strategies for mapping surface deformation in three dimensions by using multiple interferograms with different imaging geometries geometries for both current and future missions are evaluated and their abilities to resolve the displacement vector are compared the north component is always the most difficult to determine using data from near polar orbiting satellites however a satellite with an inclination of about 60 120 would enable all three components to be well resolved we attempt to resolve the 3d displacements for the 23 october 2002 nenana mountain alaska earthquake the north component s error is much larger than the signal but proxies for eastward and vertical motion can be determined if the north component is assumed negligible inversions of hypothetical coseismic interferograms demonstrate that earthquake model parameters can be well recovered from two interferograms acquired on ascending and descending tracks

long term gravitational deformation of rocks by mass rock creep abstract subsurface rocks beneath slopes are deformed to various degrees in various ways by mass rock creep mrc when they are subjected to a gravitationally unstable state for a long period mrc forms folds faults and numerous kinds of fractures such deformation is one of the main factors for deteriorating rock masses on slopes and also precursors of many landslides mrc deformations which have often been ascribed to tectonic origins can be distinguished from tectonic ones by their deformational features landforms and relationships between slope morphology and subsurface structures mrc folds are flexural slip folds that have the following mesoscopic to microscopic characteristics their axial surfaces are not smooth but are jagged and many visible openings or open fractures develop in association with the folds the jagged axial surfaces become smoother at depth and openings decrease in width with increasing overburden at the deformation site macroscopic types of mrc folds change according to the relationship between foliations and slopes buckling folds form in consequent slopes drag folds form in a deeper part of obsequent slopes and bending folds form in slopes with steep dipping foliations consequent or obsequent by downslope bowing of foliations shear fractures and tension fractures are the main deformational structures formed by mrc in massive rocks among shear fractures those of listric origin are remarkable tension fractures in general occur either in networks dividing rocks into fragments that slip and rotate irregularly in relation to each other or in parallel arrays of steeply dipping fractures an mrc fault has a shear zone consisting of a pulverized zone with gouge and a phyllitic or brecciated zone in a densely foliated rock the phyllitic zone is formed by microscopic slip along foliations in a sparsely foliated rock the brecciated zone is formed by random crushing except for the faults made through the shear fractures in massive rocks landforms due to mrc are gentle slopes bounded by horseshoe knicklines upslope convex slopes ridge top depressions multiple ridges uphill facing scarps and ridge crossing depressions

a small baseline approach for investigating deformations on full resolution differential sar interferograms this paper presents a differential synthetic aperture radar sar interferometry difsar approach for investigating deformation phenomena on full resolution difsar interferograms in particular our algorithm extends the capability of the small baseline subset sbas technique that relies on small baseline difsar interferograms only and is mainly focused on investigating large scale deformations with spatial resolutions of about 100 spl times 100 m the proposed technique is implemented by using two different sets of data generated at low multilook data and full single look data spatial resolution respectively the former is used to identify and estimate via the conventional sbas technique large spatial scale deformation patterns topographic errors in the available digital elevation model and possible atmospheric phase artifacts the latter allows us to detect on the full resolution residual phase components structures highly coherent over time buildings rocks lava structures etc as well as their height and displacements in particular the estimation of the temporal evolution of these local deformations is easily implemented by applying the singular value decomposition technique the proposed algorithm has been tested with data acquired by the european remote sensing satellites relative to the campania area italy and validated by using geodetic measurements

geological interpretation of bouguer gravity and aeromagnetic data from the gobi desert covered area eastern tianshan china implications for porphyry cu mo polymetallic deposits exploration abstract in this study bouguer gravity and aeromagnetic data have been used to better understand the geology and mineral resources near the late carboniferous late permian porphyry cu mo polymetallic mineralization in the chinese eastern tianshan belt which is extensively covered by gobi desert the reduced to pole rtp transformation of regional scale aeromagnetic data shows that the porphyry cu mo deposit is within a cluster of magnetic anomaly highs that overprint on a northeast trending magnetic gradient belt generally along the crustal scale kanguertag huangshan fault the 10 km upward continuation transformation of both bouguer gravity and aeromagnetic data indicates that the known porphyry cu mo polymetallic deposits are located on the flanks of prominent gravity and magnetic anomaly highs these anomalies are spatially correlated with the late carboniferous late permian igneous rocks and in the tuwu yandong mineralization district are centered over the granodiorite rocks genetically related to porphyry copper systems in order to minimize interpretational ambiguities a useful approach that is correlation analysis ca based on correlation coefficient cc given by gravity and magnetic data was employed to separate positively and negatively correlated anomalies features the ca procedure is applied to 10 km upward continuation transformation of both bouguer gravity and rtp transformed aeromagnetic data for mapping correlative magnetization and density contrast anomalies from deep sources which may be associated with the porphyry cu mo polymetallic mineralization five prominent cc positive anomalies have been found in the southern margin of dananhu tousuquan arc those anomalies zones could be interpreted to reflect a late carboniferous late permian magmatic belt that is favorable for additional discoveries of late carboniferous to late permian porphyry copper systems in north region of eastern tianshan

on the response of a buoyant plume to downwelling favorable wind stress here the responseof a coastallytrappedbuoyantplume to downwelling favorablewind forcingis explored using a simplified two dimensional numerical model and a prognostic theory for the resulting width depth and density anomaly and along shelf transport of the plume consistent with the numerical simulations the analytical model shows that the wind causes mixing of the plume water and that the forced cross shelf circulation can also generate significant deepening and surface narrowing as well as increased along shelf transport the response is due to a combination of the purely advective process that leads to the steepeningof the isopycnals and the entrainment of ambient water into the plume the advective component depends on the initial plume geometry plumes that have a large fraction of their total width in contact with the bottom bottom trapped suffer relatively small depth and width changes compared to plumes that have a large fraction of their total width detached from the bottom surface trapped key theoretical parameters are wg wa theratioofthewidthoftheplumedetachedfromthebottomtothewidthoftheplumein contactwith it and the ratio of the wind generated mixed layer de to the initial plume depth hp which determines the amountofwaterinitiallyentrainedintotheplume themodelresultsalsoshowthatthecross shelfcirculation can be strongly influenced by the wind driven response in combination with the geostrophic shear of the plume the continuous entrainment into the plume as well as transient events is also discussed

a modeling study of the episodic cross frontal water transport over the inner shelf of the south atlantic bight abstract physical processes that control the episodic cross frontal transport over the inner shelf of the south atlantic bight were examined using a 3d primitive turbulent closure equation model the model results showed that significant cross frontal water exchange occurred under upwelling favorable wind conditions through the detachment of isolated low salinity lenses at the outer edge of the front the formation of isolated lenses was a 3d feature associated with complex nonlinear processes it depended on 1 the amount of multiple river discharges 2 direction and magnitude of the wind and 3 tidal mixing as the total amount of river discharges increased stronger winds were required to form the isolated lenses when the river discharges were larger tidal mixing tended to delay the occurrence of isolated lenses through 1 increasing the cross shelf gradients of density and surface elevation and thus enhancing the along shelf current and reducing the along shelf variation of salinity and 2 streng

atmospheric effects in interferometric synthetic aperture radar surface deformation and topographic maps interferogram images derived from repeat pass spaceborne synthetic aperture radar systems exhibit artifacts due to the time and space variations of atmospheric water vapor other tropospheric variations such as pressure and temperature also induce distortions but the effects are smaller in magnitude and more evenly distributed throughout the interferogram than the wet troposphere term spatial and temporal changes of 20 in relative humidity lead to 10 cm errors in deformation products and perhaps 100 m of error in derived topographic maps for those pass pairs with unfavorable baseline geometries in wet regions such as hawaii these are by far the dominant errors in the spaceborne imaging radar c and x band synthetic aperature radar sir c x sar interferometric products the unknown time delay from tropospheric distortion is independent of frequency and thus multiwavelength measurements such as those commonly used to correct radar altimeter and global positioning system gps ionospheric biases cannot be used to rectify the error in the topographic case the errors may be mitigated by choosing interferometric pairs with relatively long baselines as the error amplitude is inversely proportional to the perpendicular component of the interferometer baseline for the sir c x sar hawaii data we found that the best longest baseline pair produced a map supporting 100 m contouring whereas the poorest baseline choice yielded an extremely noisy topographic map even at this coarse contour interval in the case of deformation map errors the result is either independent of baseline parameters or else very nearly so here the only solution is averaging of independent interferograms so in order to create accurate deformation products in wet regions many multiple passes may be required rules for designing optimal data acquisition and processing sequences for interferometric analyses in nondesert parts of the world are 1 to use the longest radar wavelengths possible within ionospheric scintillation and faraday rotation limits 2 for topography maximize interferometer baseline within decorrelation limits and 3 for surface deformation use multiple observations and average the derived products following the above recipe yields accuracies of 10 m for digital elevation models and 1 cm for deformation maps even in very wet regions such as hawaii

geometallurgy of the pebble porphyry copper gold molybdenum deposit alaska implications for gold distribution and paragenesis the pebble cu au mo deposit in southwest alaska is one of the world s largest porphyry deposits the deposit contains over 80 billion pounds blbs cu 107 million ounces moz au and 5 6 blbs mo in all resource categories copper and gold grades vary across diverse hydrothermal alteration assemblages with higher grades associated with sericite and pyrophyllite rich assemblages in an advanced argillic alteration zone moderate grades are associated with the potassic and sodic potassic alteration assemblages that dominate the deposit and low grades are found in quartz illite pyrite assemblages these variations reflect fluctuations in both the temperature and composition of the magmatic hydrothermal fluids in time and space qemscan scanning electron microscope based mineral mapping and in situ laser ablation inductively coupled plasmamass spectrometry methods designed to document the spatial and temporal variations in metal deportment across alteration zones show that gold occurs as inclusions of electrum and high fineness gold in chalcopyrite and pyrite and as free grains hosted by silicate minerals with the proportion of each related to the principal host alteration assemblage gold associated with the earliest high temperature sodic potassic and potassic assemblages occurs as electrum inclusions in chalcopyrite and to a lesser extent pyrite and pyrite trace element signatures have high gold silver and copper concentrations pyrite 1 during cooling of the hydrothermal system lower temperature illite and illite kaolinite alteration overprinted the earlier assemblages with varying degrees of recrystallization and precipitation of more pyrite rich assemblages with pyrite having a gold poor trace element composition pyrite 2 gold released during recrystallization formed high fineness gold inclusions in newly formed pyrite and narrow gold rich pyrite rims pyrite 3 a second magmatic hydrothermal event resulted in a sericite and pyrophyllite rich advanced argillic overprint which introduced more copper and gold to the system and recrystallized preexisting sulfides into both high and low sulfidation assemblages with high fineness gold inclusions in pyrite and chalcopyrite and solid solution gold in bornite a second generation of pyrite 1 with elevated palladium concentrations is associated with this hydrothermal fluid pulse and also possibly high arsenic pyrite pyrite 4 understanding the controls on gold deportment provides genetic constraints on ore deposit genesis alteration and sulfide assemblages and gold compositions provide information on the hydrothermal fluid compositions ph and temperature evolution of the magmatic hydrothermal system the presence of electrum inclusions in chalcopyrite and pyrite in potassic and sodic potassic alteration is consistent with these zones forming from early high temperature magmatic fluids because both gold and silver are transported together in such fluids high fineness gold inclusions in younger pyrite related to low temperature clay alteration are evidence that the gold in early electrum was partially remobilized and reprecipitated the low temperature clay alteration most likely formed from a mixture of h2s rich vapor with meteoric waters conditions where gold is transported as a bisulfide complex and silver is not resulting in the separation of the two metals a second structurally controlled pulse of magmatic fluids formed a well mineralized advanced argillic alteration assemblage containing high fineness gold inclusions in chalcopyrite and pyrite the only part of the deposit where high fineness gold is hosted by chalcopyrite in the pyrophyllite stability field acidic fluid compositions transport gold and silver as different complexes and gold solubility is significantly lower than silver leading to the precipitation of highfineness gold inclusions palladium is transported by the same complex as gold under these conditions consistent with the elevated palladium content of pyrite in the advanced argillic alteration assemblage the temporal and spatial studies of variations in gold deportment across the pebble deposit provide critical inputs to optimization of mineral processing design the greatest influence on metallurgical gold recovery at pebble is the proportion of gold that is hosted by pyrite pyrite hosted gold may require different mineral processing methodologies compared with gold hosted by chalcopyrite therefore defining domains of consistent hydrothermal alteration and sulfide mineralogy and gold deportment is the key to the geometallurgical characterization of the deposit

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

three dimensional wind driven flow in an elongated rotating basin abstract the wind driven circulation in lakes lagoons estuaries or coastal embayments is described with a linear steady three dimensional barotropic model in an elongated basin of arbitrary depth distribution on an f plane with rotation the vertically averaged velocity scales with the ekman depth rather than the maximum depth h0 as in the case without rotation near the closed ends of the basin the flow turns in viscous boundary layers because the length of the turning areas depends on the sign of the bottom slope and on the ratio of the ekman depth to h0 there is a striking contrast between the turning areas on either side of an observer looking toward the end of the basin in the northern hemisphere the turning area on the left is broad of order 1b where b is the basin half width the turning area on the right is narrow of order b and dynamically equivalent to the western boundary current in models of the wind driven ocean circulation ekman solutions are used to describe the ve

integrating airborne and multi temporal long range terrestrial laser scanning with total station measurements for mapping and monitoring a compound slow moving rock slide a slow moving compound rock slide located in the northern apennines of italy was mapped and monitored through the integration of airborne laser scanning als multi temporal long range terrestrial laser scanning tls and automated total station ats measurements landslide features were mapped using a high resolution digital terrain model hr dtm obtained by merging als and tls data in an iterative closest point icp procedure slope movements in the order of centimeters to a few decimeters were quantified with differential tls d tls based on a surface matching approach and supported by ats data to define stable reference surfaces the integrated approach allowed mapping of the composite geomorphic features of the rock slide under examination revealing its complex dynamic nature and further proving that laser scanning is a versatile and widely applicable tool for slope process analysis copyright 2013 john wiley sons ltd

the southern kahiltna terrane implications for the tectonic evolution of southwestern alaska regionally extensive and highly deformed jurassic to cretaceous basinal turbidite deposits occur along most of the inboard boundary of the talkeetna superterrane in southern alaska and western canada the southern kahiltna terrane of southwestern alaska consists largely of such basinal deposits regional and detailed studies in and adjacent to this terrane suggest several new conclusions regarding the origin of the basin and its role in the tectonic evolution of southwestern alaska stratigraphic sedimentologic compositional and structural evidence suggests that the upper jurassic to lower cretaceous strata of the southern kahiltna terrane were derived from and deposited on rocks of the adjacent talkeetna superterrane deposition of these clastic rocks apparently postdated arc magmatism in the talkeetna superterrane suggesting deposition in a basin developed on the suture between the talkeetna superterrane and north america if true this observation implies that collision of the talkeetna superterrane with north america began prior to latest jurassic time probably at a more southerly location the superterrane has since been translated northward probably by coast parallel strike slip displacement to its present location where it was structurally juxtaposed with middle to upper creteceous rocks of the kuskokwim group a magmatic overprint indicates that the talkeetna superterrane was in approximately its present location by latest cretaceous to paleocene time

structural constraints on deep seated slope deformation kinematics abstract a significant sackung type deep seated slope gravitational deformation dsgsd was recognised for the first time by the authors in the middle part of valfurva east of bormio rhaetian alps italy the reconstruction of its kinematics age and state of activity is presented through a detailed description of its morphological geomechanical and structural features an integrated multi disciplinary approach was performed to achieve a clear comprehension of the phenomenon field surveys and aero photo interpretation were carried out in order to clarify the structural geological and geomorphological setting in which the dsgsd developed a kinematic conceptual model of the slope deformation was developed through the analysis of morpho structures of their significance and relationships with lithological markers and quaternary deposits after a geomechanical characterisation of the rock mass involved in the slope deformation numerical modelling was performed to verify the hypotheses made on kinematics and driving factors of the phenomenon the sackung affects pre permian metapelites metabasites and marbles belonging to the upper austroalpine basement of the campo nappe as well as late pleistocene and holocene glacial and rock glacier deposits the deformation started after the late wurmian age 15 000 11 000 years b p and continued until few centuries ago not excluding a present day low rate activity deformation consists in a large oblique sagging along a deep confined sliding surface associated with gravitational reactivation of pre existing late alpine and recent tectonic brittle structures leading to the formation of n s and wnw ese trending gravitational morpho structures the evolution of the wnw ese trending system resulting in asymmetric trenches led to progressive failure of the lower part of the slope during the last 10 000 years as testified by large paleo landslide accumulations and it is still in progress numerical modelling indicates post glacial unloading as the main triggering factor of the slope deformation the importance of this deep seated slope deformation is enhanced by the occurrence of the 30 mm 3 active ruinon landslide in the lower part of the slope such landslide is subjected to rapid evolution and threatens the valley floor establishing an important risk factor connected to human lives and socio economic activities

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

ocean currents along a nearshore frontal zone on the continental shelf of the southeastern united states abstract river and estuarine discharges mix to form a frontal zone along a 400 km length of the coast of the south eastern united states the frontal width extends from the coast outward 10 20 km two ships anchored across the frontal zone during autumn obtained simultaneous hourly profiles of currents and density for five consecutive tidal cycles the frontal zone contained a baroclinic coastal current flowing southward the flow was strongly convergent more water entered on the coastal side than exited on the seaward side much of the inflow was apparently turned southward thus the frontal zone acted as a dynamic barrier that inhibited the advection of mixed river discharge farther offshore a thermal wind relationship suitably predicted vertical shear through the frontal zone bottom friction seemed to play only a secondary role data suggest that the baroclinic coastal current was modified by the presence of a barotropic current seaward of the frontal zone the force responsible for the barotrop

geological model of the aknes rockslide western norway abstract aknes is known as the most hazardous rockslide area in norway at present and is among the most investigated rockslides in the world representing an exceptional natural laboratory this study focuses on structural geology and the usage of geophysical methods to interpret and understand the structural geometry of the rockslide area the interpretations are further used to build a geological model of the site this is a large rockslide with an estimated volume of 35 40 million m 3 derron et al 2005 defined by a back scarp a basal shear zone at about 50 m depth and an interpreted toe zone where the sliding surface daylights the surface the rockslide is divided into four sub domains experiencing extension in the upper part and compression in the lower part structural mapping of the area indicates that the foliation of the gneiss plays an important role in the development of this rockslide the upper boundary zone of the rockslide is seen as a back scarp that is controlled by and parallel to the pre existing steep foliation planes where the foliation is not favourably orientated in regard to the extensional trend the back scarp follows a pre existing fracture set or forms a relay structure the foliation in the lower part dipping 30 to 35 to s sse seems to control the development of the basal sliding surface with its subordinate low angle trust surfaces which daylights at different levels the sliding surfaces are sub parallel to the topographic slope and are located along mica rich layers in the foliation geophysical surveys using ground penetrating radar gpr refraction seismic and 2d resistivity profiling give a coherent understanding of undulating basal sliding surface in the subsurface the geophysical surveys map the subsurface in great detail to a depth ranging from 30 40 m for gpr to approximately 125 m for refraction seismic and 2d resistivity profiling this gives a good control on the depth and lateral extent of the basal sliding surface and its subordinate low angle thrusts drill cores and borehole logging add important information with regard to geological understanding of the subsurface fracture frequency fault rock occurrences geophysical properties and groundwater conditions both in outcrops and or drill cores constrain the geometrical and kinematic model of aknes rockslide

evidence of rock slope breathing using ground based insar ground based interferometric synthetic aperture radar gb insar campaigns were performed in summer 2011 and 2012 in the romsdalen valley more romsdal county western norway in order to assess displacements on mannen bora rock slope located 1 km northwest a second gb insar system continuously monitors the large mannen rockslide the availability of two gb insar positions creates a wide coverage of the rock slope including a slight dataset overlap valuable for validation a phenomenon of rock slope breathing is detected in a remote and hard to access area in mid slope millimetric upward displacements are recorded in august 2011 analysis of 2012 gb insar campaign combined with the large dataset from the continuous station shows that the slope is affected by inflation deflation phenomenon between 5 and 10 mm along the line of sight the pattern is not homogenous in time and inversions of movement have a seasonal recurrence these seasonal changes are confirmed by satellite insar observations and can possibly be caused by hydrogeological variations in addition combination of gb insar results in situ measurements and satellite insar analyses contributes to a better overview of movement distribution over the whole area

multi sensor advanced dinsar monitoring of very slow landslides the tena valley case study central spanish pyrenees abstract in this work it is demonstrated how the combination of multi sensor and multi temporal sar data improves the monitoring capacity of very slow landslides the study area is the upper tena valley central spanish pyrenees where mostly very slow earth flows have caused direct damage estimated at approximately 15 m in the last decade the advanced dinsar processing of ascending orbit alos palsar images 2006 2010 and descending orbit ers envisat 2001 2007 and terrasar x 2008 datasets has provided heterogeneous displacement velocity measurements the projection along the steepest slope of los displacements reduces the geometrical differences introduced by each satellite these results were compared and validated with available d gps measurements in a second step ps displacement data are combined with a landslide inventory increasing the number of monitored landslides with sufficient ps from 4 to 19 obtained from c and x band data to 38 of the total 294 finally the retrieved multi sensor landslides velocities are classified with respect to the magnitude of road damages that occurred in the 2008 2010 period at local scale the combination of multi sensor data was useful to differentiate different landslide displacement directions to measure different velocity patterns within the same moving mass and to distinguish the slower natural and faster human induced landslides the analysis of displacement time series permitted to evaluate the acceleration caused by a destabilising anthropogenic change and the correlation between displacement variability and seasonal precipitation and melting

downwelling wind tides and estuarine plume dynamics the estuarine plume dynamics under a downwelling favorable wind condition were examined in the windy dry season of the pearl river estuary pre using the pre primitive equation finite volume community ocean model fvcom the wind and tide driven estuarine circulation had a significant influence on the plume dynamics on both local and remote scales specifically the local effect of downwelling favorable winds on the plume was similar to the theoretical descriptions of coastal plumes narrowing the plume width and setting up a vertically uniform downstream current at the plume edge tides tended to reduce these plume responses through local turbulent mixing and advection from upstream regions resulting in an adjustment of the isohalines in the plume and a weakening of the vertically uniform downstream current the remote effect of downwelling favorable winds on the plume was due to the wind induced estuarine sea surface height ssh which strengthened the estuarine circulation and enhanced the plume transport accordingly associated with these processes tide induced mixing tended to weaken the ssh gradient and thus the estuarine circulation over a remote influence scale overall the typical features of downwelling favorable wind driven estuarine plumes revealed in this study enhanced our understanding of the estuarine plume dynamics under downwelling favorable wind conditions

nonlinear subsidence rate estimation using permanent scatterers in differential sar interferometry discrete and temporarily stable natural reflectors or permanent scatterers ps can be identified from long temporal series of interferometric sar images even with baselines larger than the so called critical baseline this subset of image pixels can be exploited successfully for high accuracy differential measurements the authors discuss the use of ps in urban areas like pomona ca showing subsidence and absidence effects a new approach to the estimation of the atmospheric phase contributions and the local displacement field is proposed based on simple statistical assumptions new solutions are presented in order to cope with nonlinear motion of the targets

slope deformation prior to zhouqu china landslide from insar time series analysis abstract a major landslide in zhouqu china occurred on august 8 2010 and caused widespread damage and over 1700 casualties we study the deformation of the slopes over a time period of about three years prior to the landslide by an enhanced stamps sb technique with 16 ascending alos palsar images in particular the orbit error and stratified troposphere that were not well dealt with in the original stamps sb method have been satisfactorily corrected by a novel phase ramp correction method the deformation in four regions of the study area has been retrieved with a maximum of up to 70 mm yr in the luojiayu sanyanyu valley the slopes where the 2010 giant landslide occurred have been found to be quite unstable before the event deformation exceeding 30 mm yr has been detected in the suoertou slope which is a well known place for an ancient fault zone landslide fast movement larger than 40 mm yr is observed in the xieliupo slope which poses threats of landslide dam and dammed lake to the pai lung river together with another slope deformation detected in the opposite slope in the nanshanqiaotou slope the detected 30 mm yr deformation can be viewed as the prelude of the large landslide occurred in october 2010 more important it is found that the slope deformation time series has strong correlation with the precipitation in the area as well as with the devastating wenchuan earthquake that occurred in may 2008 whose epicenter is about 300 km away from zhouqu

detailed rockslide mapping in northern norway with small baseline and persistent scatterer interferometric sar time series methods rockslides have a high socioeconomic and environmental importance in many countries norway is particularly susceptible to large rockslides due to its many fjords and steep mountains one of the most dangerous hazards related with rock slope failures are tsunamis that can lead to large loss of life it is therefore very important to systematically identify potential unstable rock slopes traditional landslide monitoring techniques are expensive and time consuming differential satellite interferometric synthetic aperture radar insar is an invaluable tool for land displacement monitoring improved access to time series of satellite data has led to the development of several innovative multitemporal algorithms small baseline sb methods are based on combining and inverting a set of unwrapped interferograms that are computed with a small perpendicular baseline in order to reduce spatial phase decorrelation another well proven technique is the persistent scatterer interferometric method psi that is based on analysis of persistent point targets in this paper we apply both approaches to study several rockslide sites in troms county in the far north of norway moreover we take the opportunity to address the difference and similarities between the sb and the psi multitemporal insar methods for displacement studies in rural terrain

monitoring land subsidence in the southern part of the lower liaohe plain china with a multi track ps insar technique abstract the lower liaohe plain is one of the most important industrial zones in liaoning province china and activities here include oil and gas exploration aquaculture and salt production heavy land use may have contributed to the different magnitudes of land deformation in this region and this has been detrimental to the environment and economic construction projects in this zone in this paper we employ the permanent scatterer interferometry psi technique with l band alos palsar imagery data to monitor the annual land subsidence and produce accumulative time series maps for the years of 2007 to 2011 the unwrapped grid size was tested in order to recover the maximum deformation insar results from two adjacent tracks were merged by considering the offset over the overlapped area a ps standard deviation of 0 91 cm year was achieved in the vertical direction according to calculation from two independent ps results three kinds of land subsidence were analyzed quantitatively over the oil fields coastal zones and salt production areas some severe land subsidence regions were verified by field investigations

landslide inventory maps new tools for an old problem landslides are present in all continents and play an important role in the evolution of landscapes they also represent a serious hazard in many areas of the world despite their importance we estimate that landslide maps cover less than 1 of the slopes in the landmasses and systematic information on the type abundance and distribution of landslides is lacking preparing landslide maps is important to document the extent of landslide phenomena in a region to investigate the distribution types pattern recurrence and statistics of slope failures to determine landslide susceptibility hazard vulnerability and risk and to study the evolution of landscapes dominated by mass wasting processes conventional methods for the production of landslide maps rely chiefly on the visual interpretation of stereoscopic aerial photography aided by field surveys these methods are time consuming and resource intensive new and emerging techniques based on satellite airborne and terrestrial remote sensing technologies promise to facilitate the production of landslide maps reducing the time and resources required for their compilation and systematic update in this work we first outline the principles for landslide mapping and we review the conventional methods for the preparation of landslide maps including geomorphological event seasonal and multi temporal inventories next we examine recent and new technologies for landslide mapping considering i the exploitation of very high resolution digital elevation models to analyze surface morphology ii the visual interpretation and semi automatic analysis of different types of satellite images including panchromatic multispectral and synthetic aperture radar images and iii tools that facilitate landslide field mapping next we discuss the advantages and the limitations of the new remote sensing data and technology for the production of geomorphological event seasonal and multi temporal inventory maps we conclude by arguing that the new tools will help to improve the quality of landslide maps with positive effects on all derivative products and analyses including erosion studies and landscape modeling susceptibility and hazard assessments and risk evaluations

relating river plume structure to vertical mixing abstract the structure of a river plume is related to the vertical mixing using an isohaline based coordinate system salinity coordinates offer the advantage of translating with the plume as it moves or expanding as the plume grows this coordinate system is used to compare the relative importance of different dynamical processes acting within the plume and to describe the effect each process has on the structure of the plume vertical mixing due to inertial shear in the outflow of a narrow estuary and wind mixing are examined using a numerical model of a wind forced river plume vertical mixing and the corresponding entrainment of background waters is greatest near the estuary mouth where inertial shear mixing is large this region is defined as the near field with the more saline far field plume beyond wind mixing increases the mixing throughout the plume but has the greatest effect on plume structure at salinity ranges just beyond the near field wind mixing is weaker at high salinity classes tha

rockslide tsunamis in complex fjords from an unstable rock slope at akerneset to tsunami risk in western norway abstract an unstable rock volume of more than 50 million m 3 has been detected in the akerneset rock slope in the narrow fjord storfjorden more romsdal county western norway if large portions of the volume are released as a whole the rockslide will generate a tsunami that may be devastating to several settlements and numerous visiting tourists along the fjord the threat is analysed by a multidisciplinary approach spanning from rock slope stability via rockslide and wave mechanics to hazard zoning and risk assessment the rockslide tsunami hazard and the tsunami early warning system related to the two unstable rock slopes at akerneset and hegguraksla in the complex fjord system are managed by aknes tafjord beredskap iks previously the aknes tafjord project the present paper focuses on the tsunami analyses performed for this company to better understand the effects of rockslide generated tsunamis from akerneset and hegguraksla two and three dimensional site specific laboratory experiments are conducted to study the generation propagation and run up of the wave for several potential rockslide scenarios from akerneset furthermore the two models globouss and dpwaves are applied for numerical simulations of the generation propagation phase and a third model most is applied for numerical simulations of the near shore propagation and inundation of the wave in selected locations strong emphasis is put on verification validation and sensitivity of the numerical models the best match between the numerical simulations and the laboratory experiments is found for the larger scenarios with the linear dispersive solution for the propagation phase the corresponding calculated run up values are remarkably similar to the ones observed during the laboratory experiments during the risk assessment it was found that the rockslide tsunami hazard probability of impact is higher than accepted by the norwegian planning and building act this should at that time prevent any further development in all the exposed areas of the entire fjord system the act is today altered to open for specified further development in the various hazard zones the results of the tsunami analyses are applied in risk management in terms of hazard map production and land use planning two failure scenarios for each of the two unstable rock slopes are designed for the hazard zoning the larger and less probable scenarios 1 in 5000 years are applied for evacuation zones and routes while the smaller and more probable scenarios larger than 1 in 1000 years are applied for location and design of less critical facilities accepted in the inundation zone

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

mapping small elevation changes over large areas differential radar interferometry a technique that uses synthetic aperture radar sar images to measure very small 1 cm or less surface motions with good resolution 10 m over large swaths 50 km is presented along with experimental results the method could be used for accurate measurements of many geophysical phenomena including swelling and buckling in fault zones residual displacements from seismic events and prevolcanic swelling the method is based on sar interferometry where two images are made of a scene by simultaneously flying two physically separated antennas then the phases of corresponding pixels are differenced and altitude formation is deduced from some simple computation and image rectification it is also possible to use one antenna flown twice over the same scene then if the second flight exactly duplicates the track of the first an interesting possibility occurs there would be no phase changes between the images at all unless there was a physical change in the scene such as ground swelling that would alter the distance from some resolution element to the antenna since the phase changes all occur at the short carrier wavelength the basic limitation on sensitivity is only the phase noise in the system when the two imaging passes are made from flight tracks that are separated which is the case with the seasat images used here it is no longer possible to distinguish surface changes from the parallax caused by topography however with some additional computation a third image made at some other baseline may be used to remove the topography and leave only the surface changes this method was applied using seasat data to an imaging site in imperial valley california where motion effects were observed that were ascribed to the expansion of water absorbing clays phase change images of this area are shown along with associated ground truth about the presence of water problems with the technique are explored along with a discussion of future experimental possibilities on upcoming sar missions like earth observing system eos earth resources satellite ers 1 sir c and the venus imaging radar magellan

mineral potential mapping in an accreted island arc setting using aeromagnetic data an example from southwest alaska the distribution of volcanogenic massive sulfide vms porphyry epithermal alaska type ultramafic mafic complexes intrusion related au and granitoid sn w ore deposits in southwest alaska supports current metallogenic models linking the formation of these deposit types to the emplacement of different suites of igneous rocks during the evolution of this convergent plate margin regional scale aeromagnetic data provide a continuous set of observations over the deposits and show contrasting patterns over the igneous rock suites hosting the various deposit types combined with surface geologic data and regional metallogenic constraints aeromagnetic data filtered to enhance the anomalous magnetic field and map magnetic domains were used to produce a mineral potential map across this accreted island arc setting the reduced to pole upward continuation and total horizontal gradient transform maps show anomalies that could represent porphyry epithermal deposits within the intraoceanic and continental arc terranes the tilt derivative transform highlights lineaments within the back arc that may represent zones with potential for vms deposits the truncations of tilt derivative lineaments outline a major magnetic domain boundary between the back arc and craton margin which is prospective for granitoid sn w deposits annular tilt derivative highs outline granitoids that could be associated with intrusion related au deposits within the craton margin shallow magnetite rich alaska type ultramafic mafic complexes are mapped by their short wavelength high amplitude anomalies successful mineral potential mapping across southwestern alaska as performed in the present study suggests that filtered aeromagnetic data can be effectively used in mineral exploration in convergent continental margin settings

use of differential sar interferometry in monitoring and modelling large slope instability at maratea basilicata italy abstract differential synthetic aperture radar sar interferometry diffsar allows in principle to measure very small movements of the ground and to cover in continuity large areas so that it can be considered as a potentially ideal tool to investigate landslides and other slope instability in this paper we explore the use of this technique to improve our knowledge of the slope instability of a well investigated area the maratea valley affected by continuous slow movements producing an impressive sackung type phenomenon which poses several unanswered questions in particular by using this technique we analyse the time evolution of ground movements from 1997 to 2000 the slope movements during this same time interval have also been monitored in the past by using other techniques such as electronic distance meter edm and gps measurements gps and diffsar results are here compared in our implementation of the diffsar technique the problem of decorrelation noise is faced by using a phase unwrapping approach that allows to process sparse data and the impact of atmospheric artefacts is reduced by performing a temporal analysis of the deformations observed in successive interferograms in this study we also show that it is possible to perform a temporal analysis of continuous slow landslide movements by using a limited number of ers sar data sets and low precision topographic information all the acquired data edm gps and diffsar are consistent and allow a kinematic model of instability within the investigated time interval to be proposed a map of slopes subject to different velocities of vertical displacements was delineated modifying previous knowledge within the valley progressive and almost linear displacements over time were confirmed

geological analysis of aeromagnetic data from southwestern alaska implications for exploration in the area of the pebble porphyry cu au mo deposit aeromagnetic data are used to better understand the geology and mineral resources near the late cretaceous pebble porphyry cu au mo deposit in southwestern alaska the reduced to pole rtp transformation of regional scale aeromagnetic data shows that the pebble deposit is within a cluster of magnetic anomaly highs similar to pebble the iliamna kijik and neacola porphyry copper occurrences are in magnetic highs that trend northeast along the crustal scale lake clark fault a high amplitude short to moderate wavelength anomaly is centered over the kemuk occurrence an alaska type ultramafic complex similar anomalies are found west and north of kemuk a moderate amplitude moderate wavelength magnetic low surrounded by a moderate amplitude short wavelength magnetic high is associated with the gold bearing shotgun intrusive complex the rtp transformation of the district scale aeromagnetic data acquired over pebble permits differentiation of a variety of jurassic to tertiary magmatic rock suites jurassic cretaceous basalt and gabbro units and late cretaceous biotite pyroxenite and granodiorite rocks produce magnetic highs tertiary basalt units also produce magnetic highs but appear to be volumetrically minor eocene monzonite units have associated magnetic lows the rtp data do not suggest a magnetite rich hydrothermal system at the pebble deposit the 10 km upward continuation transformation of the regional scale data shows a linear northeast trend of magnetic anomaly highs these anomalies are spatially correlated with late cretaceous igneous rocks and in the pebble district are centered over the granodiorite rocks genetically related to porphyry copper systems the spacing of these anomalies is similar to patterns shown by the numerous porphyry copper deposits in northern chile these anomalies are interpreted to reflect a late cretaceous magmatic arc that is favorable for additional discoveries of late cretaceous porphyry copper systems in southwestern alaska

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

the influence of wind forcing on the chesapeake bay buoyant coastal current observations of the buoyant coastal current that flows southward from chesapeake bay are used to describe how the thickness width and propagation speed vary in response to changes in the along shelf wind stress three basic regimes were observed depending on the strength of the wind for weak wind stresses from 0 02 to 0 02 pa the buoyant coastal current was relatively thin the front slope was not steep and the width was variable 1 20 km for moderate downwelling southward wind stresses 0 02 0 07 pa wind driven cross shelf advection steepened the front causing the plume to narrow and thicken for stronger downwelling wind stresses greater than 0 07 pa vertical mixing dominated bulk richardson numbers were approximately 0 25 isopycnals were nearly vertical and the plume front widened but the plume width did not change plume thickness and width were normalized by the theoretical plume scales in the absence of wind forcing normalized plume thickness increased linearly from 1 to 2 as downwelling wind stresses increased from 0 to 0 2 pa normalized plume widths were approximately 1 for downwelling wind stresses from 0 02 to 0 2 pa the observed along shelf propagation speed of the plume was roughly equal to the sum of the theoretical propagation speed and the wind driven along shelf flow

the complete 3 d surface displacement field in the epicentral area of the 1999 mw7 1 hector mine earthquake california from space geodetic observations we use interferometric synthetic aperture radar insar data to derive continuous maps for three orthogonal components of the co seismic surface displacement field due to the 1999 m w7 1 hector mine earthquake in southern california vertical and horizontal displacements are both predominantly antisymmetric with respect to the fault plane consistent with predictions of linear elastic models of deformation for a strike slip fault some deviations from symmetry apparent in the surface displacement data may result from complexity in the fault geometry

observations and numerical modeling of the pearl river plume in summer season a cruise survey of the pearl river plume during southeasterly and southwesterly winds two typical wind patterns in summer in guangdong coastal waters is reported and the cruise data are analyzed to unveil the plume dynamics the kelvin number is derived from the in situ data revealing that the pearl river plume exhibits two different scales in response to the two kinds of the wind forcing numerical model simulations based on the regional oceanic modeling system roms with nesting domains are implemented to explore details of the plume dynamics validated by cruise observations and tidal gauge sea level data modeling results suggest that there is a subtidal anticyclonic recirculation bulge on the west side out of the estuary mouth under southeasterly winds showing a recirculating plume in the near field when the wind changes to the southwesterly however the recirculating plume vanishes the distinct supercritical tidal plume front occurs with southeasterly winds prevailing in spring tide due to the strong advection in the tidal plume the tidal salt deficit flux can reach as high as 12 5 of the mean current flux and illustrates the combined forcing of tide and wind key points the paper clarifies the pearl river plume anatomy under two typical winds spring tide facilitates the supercritical pearl river tidal plume front tide determines tidal salt deficit flux strength wind determines the direction

temporal patterns of nonseismically triggered landslides in shaanxi province china abstract examination of the temporal patterns of landslide events provides valuable insights into the baseline information used to determine landslide activity and perform risk assessment in a given area we collected a catalog of historical nonseismically triggered landslides that occurred over 22 years in shaanxi province china we found that the annual number of slides was significantly related to the annual number of falls the average annual numbers of slides and falls were approximately 17 and 10 respectively the active and nonactive periods of landslides alternated within the time series of the annual number of landslides an empirical power law correlation exists between the complementary cumulative frequency and the annual number of landslides the monthly distribution of landslide events is significantly associated with monthly rainfall most landslide events occurred in the rainy season between july and october the average time intervals of falls and slides from july to october were approximately 12 days and 8 days respectively moreover the temporal distribution of landslide events is clustered owing to the impact of nonuniformly distributed rainfall activities most of the landslides concentrated in one or two months of a year furthermore the nonzero values in the landslide time series are nonuniformly spaced the complementary cumulative frequency distribution of the time intervals between landslide events can be adequately fitted by an exponential function based on these equations the temporal probabilities of landslide events can be predicted in addition most of the nonseismically triggered landslides in shaanxi province were triggered by long term antecedent rainfall and high intensity intraday rainfall

dynamics of slow moving landslides from permanent scatterer analysis high resolution interferometric synthetic aperture radar insar permanent scatterer data allow us to resolve the rates and variations in the rates of slow moving landslides satellite to ground distances range changes on landslides increase at rates of 5 to 7 millimeters per year indicating average downslope sliding velocities from 27 to 38 millimeters per year time series analysis shows that displacement occurs mainly during the high precipitation season during the 1997 1998 el nino event rates of range change increased to as much as 11 millimeters per year the observed nonlinear relationship of creep and precipitation rates suggests that increased pore fluid pressures within the shallow subsurface may initiate and accelerate these features changes in the slope of a hill resulting from increases in the pore pressure and lithostatic stress gradients may then lead to landslides

spatial analysis of surface deformation distribution detected by persistent scatterer interferometry in lanzhou region china persistent scatterer synthetic aperture radar interferometry ps insar is a remote sensing method that can be used to detect surface deformation which is an indicator of potential geohazards by capturing such deformations over time it is possible to obtain valuable information regarding geohazards such as landslides this study focused on the use of ps insar to investigate the distribution and causes of surface deformation in the lanzhou region of gansu province in china between 2003 and 2010 41 advanced synthetic aperture radar images were captured by the envisat satellite and analyzed using ps insar and the correlation between the observed surface deformation and topographic geologic and anthropogenic factors was derived based on a geographic information system platform it was found that the largest number and highest density of surface deformations occurred at elevations of 1486 1686 m it was also established that slope ranges of 25 30 and 35 40 are threshold values at which surface deformation changes abruptly and that slopes with north and northwest aspects are most prone to surface deformation the lithologies most susceptible to surface deformation are clay sandy soil and loess the normalized difference vegetation index indicated that surface deformation occurred most often in areas with sparse vegetation anthropogenic activities e g construction and wastewater discharge could be inferred as causal mechanisms of surface deformation comparison of the distributions of geohazards and surface deformation showed considerable consistency which proves surface deformation can induce geohazards these results could help governments improve urban planning and geohazard mitigation

early tertiary paleomagnetic evidence and the displacement of southern alaska paleomagnetic data from early paleocene lavas a few kilometers north of lake clark just inboard of the peninsular terrane indicate modest post early tertiary latitudinal displacement and about 55 sup 0 of counterclockwise rotation of this region with respect to north america a nearby middle eocene sequence of lava flows however gives no indication of displacement or rotation south of lake clark the paleomagnetism of five paleogene 30 to 40 ma volcanic sequences that are a part of the peninsular terrane proper shows no northward translation and no rotation a major part of the northward movement documented by other studies in the gulf of alaska region may be accounted for by cumulatively significant intraterrane displacements 32 references 3 figures 1 table

tectonic setting of the pebble and other copper gold molybdenum porphyry deposits within the evolving middle cretaceous continental margin of northwestern north america the pebble cu au mo deposit in southwestern alaska containing the largest gold resource of any known porphyry in the world developed in a tectonic setting significantly different from that of the present day it is one of a series of metalliferous middle cretaceous porphyritic granodiorite quartz monzonite and diorite bodies evolved from lower crust and metasomatized lithospheric mantle melts which formed along much of the length of the north american craton suture with the peninsular alexander wrangellia arc the porphyry deposits were emplaced within the northernmost two of a series of ca 130 to 80 ma flysch basins that define the suture as well as into arc rocks immediately seaward of the two basins deposits include the ca 100 to 90 ma pebble neacola and other porphyry prospects along the kahiltna basin peninsula terrane boundary and the ca 115 to 105 ma baultoff carl creek horsfeld orange hill bond creek and chisna porphyries along the nutzotin basin wrangellia terrane boundary the porphyry deposits probably formed along the craton margin more than 1 000 km to the south of their present latitude palinspastic reconstructions of plate kinematics from this period are particularly difficult because magmatism overlaps the 119 to 83 ma cretaceous normal superchron a period when sea floor magnetic data are lacking our favored scenario is that ore formation broadly overlaps the cessation of sedimentation and contraction and the transition to a transpressional continental margin regime such that the remnant ocean basins were converted to strike slip basins the basins and outboard peninsular alexander wrangellia composite superterrane which are all located seaward of the deep crustal denali farewell fault system were subjected to northerly dextral transpression for as long as perhaps 50 m y beginning at ca 95 10 ma the onset of this transpression was marked by development of the mineralized bodies along fault segments on the seaward side of the basins geochemical and radiogenic isotopic data for igneous rocks associated with the pebble porphyry deposit suggest continuous melt derivation from enriched lithosphere of a recently metasomatized mantle these geochemical characteristics coupled with the arc continent related collisional setting suggest that lithospheric thickening and postcollisional lithospheric melting are the most likely cause of the ore related magmatism subsequent to translation of the alaskan margin terranes and early tertiary oroclinal bending of alaska the northernmost kahiltna basin and the pebble deposit as well as the other porphyry systems reached their present day locations along southern alaska

tropospheric corrections of sar interferograms with strong topography application to etna the accuracy of spaceborne geodetic techniques including sar interferometry is limited by the time and spatial variation and altitude dependance of the propagation delay of electomagnetic waves in the lower troposphere particularly in mountainous areas in this paper we use a 1d model developed for tropospheric corrections of gps and doris measurements to correct sar data the differential tropospheric delay is computed at each pixel of the interferogram from ground temperature humidity and pressure using two empirical parameters calibrated from several radio soundings acquired in various latitude and climate conditions it is shown that with such a model given the 3300 meters topography of etna tropospheric variations can generate up to 4 phase rotations between the top and the bottom of the volcano in 16 out of the 20 interferograms processed with images acquired between august 1992 and october 1993 correction of the tropospheric effect reduces the number of fringes associated with the 1991 93 eruption from previous estimates the remaining deformation is consistant with a deforming source located at a depth of 14 1 km during the second half of the eruption the subsidence rate at the top of the volcano is roughly stable at 13 3 mm month these values are in good agreement with tiltmeter data collected on etna during the same period and with the estimated volume of erupted material no significant deformation can be observed during the last month of eruption inflation of the volcano seems to resume immediately after the end of the eruption at a rate of 3 mm month

active normal fault control on landscape and rock slope failure in northern norway structural geomorphic and interferometric synthetic aperture radar insar surface displacement data show that uplift of the northernmost onshore scandinavian passive margin is associated with active normal faulting and anomalous clusters of landslides regional scale normal faults separate alpine footwall ranges with impressive range front scarps from more gentle hanging wall topography in the lyngen region rockslides sackung features i e deep seated slope gravitational deformation and active faults cluster inside an 1000 km 2 area of hanging wall subsidence parallel to an 30 km long faceted range front scarp from postglacial to recent time rockslides have been released along the main range front and other propagating scarps both in the footwall range and in structurally controlled glacially oversteepened valleys of the hanging wall the active rockslides moving at rates of 10 mm yr show a variety of relationships to the controlling structures reflecting tectonic as well as gravitational faulting recent and present day landscape evolution and large volume rockslide distribution in scandinavia should be viewed from the perspective of tectonic processes involving active normal faults

application of bi dimensional empirical mode decomposition bemd modeling for extracting gravity anomaly indicating the ore controlling geological architectures and granites in the gejiu tin copper polymetallic ore field southwestern china the gejiu tin copper polymetallic ore field located at the westernmost end of the cathaysia block in south china is one of the largest tin polymetallic ore fields in the world it is associated with magmatic hydrothermal ore forming processes triggered by deeply seated structures and concealed granites the bi dimensional empirical mode decomposition bemd was used to decompose gravity data covering an area including the gejiu tin copper polymetallic ore field in the west and the bozhushan silver lead zinc polymetallic ore field in the east which yielded three two dimensional intrinsic mode function bimfs images and one residue res m n image that depict four layers of geological architectures at different wavelengths within the study area the high pass filtered gravity component image bimf1 is interpreted to depict the shallow geological architecture which indicates that the skarn alteration and tin copper mineralization with positive gravity anomalies are distributed around the granites characterized by negative gravity anomalies the band pass filtered gravity component image bimf2 is interpreted to depict the middle shallow geological architecture which indicates that the outcropped granites in the western gejiu ore field bounded by the gejiu fault may extend to the eastern gejiu ore field to form one integrated granitic complex in the subsurface the other band pass filtered gravity component image bimf3 is interpreted to depict the middle lower geological architecture which indicates that there may be an ew trending granite zone with negative gravity anomaly at middle lower depth connecting the gejiu tin copper polymetallic field to the bozhushan silver lead zinc polymetallic field displaying the existence of an ew trending regional polymetallic ore forming zone within the study area the low pass filtered gravity component image res m n is interpreted to depict the lowest geological architecture within the study area which reflects that there may be a pair of the nw trending uplift zone of the mantle and or the basement with positive gravity anomaly and the depression zone of the mantle and or the basement with negative gravity anomaly the gejiu tin copper polymetallic deposits and the related granites are located at the transitional zone between the uplift and depression whereas the bozhushan silver lead zinc polymetallic deposits and the related granites are situated within the depression zone which implies that the diversity of the late yanshanian granites and the related polymetallic deposits in the study area may be controlled by the complexity of the crust mantle interaction at depth

deformation responses of slow moving landslides to seasonal rainfall in the northern apennines measured by insar abstract slow moving landslides are widespread geomorphological features in the northern apennines of italy where they represent one of the main landscape forming processes the lithology of the northern apennines fold and thrust belt is characterized by alternations of sandstone siltstone and clayshales also known as flysch and clay shales with a chaotic block in matrix fabric which are often interpreted as tectonic or sedimentary melanges while flysch rocks with a high pelitic fraction host earthslides that occasionally evolve into flow like movements earthflows are the dominant landslide type in chaotic clay shales in the present work we document the kinematic response to rainfall of landslides in these different lithologies using radar interferometry the study area includes three river catchments in the northern apennines here the mediterranean climate is characterized by two wet seasons during autumn and spring respectively separated by dry summers and winters with moderate precipitation we use sar imagery from the x band satellite cosmo skymed and from the c band satellite sentinel 1 to retrieve spatial displacement measurements between 2009 and 2016 for 25 landslides in our area of interest we also document detailed temporal and spatial deformation signals for eight representative landslides although the insar derived deformation signal is only well constrained by our dataset during the years 2013 and 2015 in spring 2013 long enduring rainfalls struck the study area and numerous landslide reactivations were documented by the regional authorities during 2013 we measured higher displacement rates on the landslides in pelitic flysch formations compared to the earthflows in the clay shales slower mean velocities were measured on most landslides during 2015 we analyse the temporal deformation signal of our eight representative landslides and compare the temporal response to precipitation we show that earthslides in pelitic flysch formations accelerate faster than earthflows in chaotic clay shales and reach higher velocities while the kinematic behaviour of the earthflows can be described as rather steady with only minor accelerations although we have no detailed pore pressure measurements for the period of interest the observed behaviour can be explained in our view by the morphological and hydrological characteristics of the different landslide types on the one hand landslide material and bedrock in the pelitic flysch rocks are more resistant which is why slope angles are higher in this lithology on the other hand landslides in the pelitic flysch formations have often deeper slip surfaces and landslide material is more permeable this is why long persistent rainfall is necessary to saturate the landslide material and induce pore pressures that are high enough to trigger displacement

circulation in the arctic ocean results from a high resolution coupled ice sea nested global fvcom and arctic fvcom system abstract a high resolution unstructured grid global regional nested ice current coupled fvcom system was configured for the arctic ocean and used to examine the impact of model resolution and geometrical fitting on the basin coastal scale circulation and transport in the pan arctic with resolving steep bottom slope and irregular coastal geometry the model was capable of simulating the multi scale circulation and its spatial variability in the arctic basin and flow through the bering strait fram strait and canadian archipelago the model simulated annual mean velocities were in good agreement with observations within the measurement uncertainty and variability due to insufficient sampling the errors in the flow direction varied with the flow speed larger in the weak velocity zone and smaller as the velocity increased in the upper 50 m layer the annual mean circulation pattern was dominated by the wind and ice drifting induced anticyclonic circulation in the arctic basin and a relatively strong cyclonic slope current along the edge of the continental shelf in the deep 200 600 m layer a relatively permanent cyclonic circulation occurred along the steep bottom slope these annual mean circulations accounted for 85 of the total kinetic energy variance de trending the mean flow an empirical orthogonal function eof analysis showed that the semi annual and seasonal variability of the sub tidal flow was dominated by the first and second modes that accounted for 46 and 30 of the total variance in the upper 50 m layer and 58 and 20 in the deep 200 600 m layer consistent with observations the ao fvcom simulated cyclonic slope flow was characterized by a large positive topostrophy sensitivity experiment results with various grid configurations suggested that the currents over slopes narrow straits and water passages featured topographic and baroclinic frontal dynamical scales associated with bathymetric slope and internal rossby deformation radius over the arctic slope since these two scales are in the same order the along slope current could be captured as the cross isobath model resolution was refined to resolve the steep bottom topography under this condition there is no need to add neptune forcing into the momentum equations the accuracy of the estimation of the transport through the strait and narrow water passage was affected by the model resolution in fram strait where the flow is characterized by strong lateral current shear resulting from the atlantic inflow and arctic outflow the transport estimation could have a significant uncertainty due to both horizontal and vertical sampling resolutions

the giant pebble cu au mo deposit and surrounding region southwest alaska introduction the pebble deposit is located about 320 km southwest of and 27 km northwest of the village of iliamna in alaska fig 1a it is one of the largest porphyry deposits in terms of contained cu fig 2a and it has the largest au endowment of any porphyry deposit in the world fig 2b the deposit comprises the pebble west and pebble east zones that represent two coeval hydrothermal centers within a single system lang et al 2013 together the measured and indicated resources total 5 942 million metric tons mt at 0 42 cu 0 35 g t au and 250 ppm mo with an inferred resource of 4 835 mt at 0 24 cu 0 26 g t au and 215 ppm mo in addition the deposit contains significant concentrations of ag pd and re northern dynasty minerals 2011 fig 1 a map of southwestern alaska showing extensive cover by tertiary and quaternary deposits and locations of known mineral deposits with outline of the pebble district distribution of tertiary and quaternary deposits is after wilson et al 2006 b map of the pebble district showing locations of deposits all deposits are named as zones for example the 37 zone regional mineral deposit locations are from u s geological survey 2008 descriptions of district deposits are in hawley 2004 and lang et al 2013 boundaries for the pebble west and pebble east zones are based on 0 3 and 0 6 cu equiv respectively fig 2 the 25 largest porphyry copper deposits based on a the tonnage of contained copper metal and b the tonnage of contained gold modified from cooke et al 2005 the classifications of deposits into cu mo cu au mo and cu au types are described in cooke et al 2005 unlike most porphyry deposits in southwest alaska which are 75 ma u s geological survey 2008 re os

comprehensive approaches to 3d inversion of magnetic data affected by remanent magnetization three dimensional 3d inversion of magnetic data to recover a distribution of magnetic susceptibility has been successfullyusedformineralexplorationduringthelastdecade however the unknown direction of magnetization has limited the use of this technique when significant remanence is present we have developed a comprehensive methodology for solving this problem by examining two classes of approaches and have formulated a suite of methods of practical utility the first class focuses on estimating total magnetization direction and then incorporating the resultant direction into an inversion algorithm that assumes a known direction thesecondclassfocusesondirectinversionoftheamplitude of the magnetic anomaly vector amplitude data depend weaklyuponmagnetizationdirectionandareamenabletodirect inversion for the magnitude of magnetization vector in 3d subsurface two sets of high resolution aeromagnetic dataacquiredfordiamondexplorationinthecanadianarctic areusedtoillustratethemethods usefulness

investigating landslides with space borne synthetic aperture radar sar interferometry abstract this paper is addressed to readers without advanced knowledge of remote sensing it illustrates some current and potential uses of satellite synthetic aperture radar interferometry insar for landslide assessment data acquired by sar systems can provide 3d terrain models and be used to assist in regional scale investigations e g aimed at evaluation of susceptibility of slopes to failure under favourable environmental conditions the innovative permanent scatterers ps technique which overcomes several limitations of conventional sar differential interferometry dinsar applications in landslide studies is suitable for monitoring slope deformations with millimetric precision the ps technique combines the wide area coverage typical of satellite imagery with the capability of providing displacement data relative to individual image pixels with the currently available radar satellites however only very slow ground surface displacements can be reliably detected and measured the presented case study of a landslide from the liechtenstein alps indicates that the most attractive and reliable contribution provided by this remote sensing technique lies in the possibility of i wide area qualitative distinction between stable and unstable areas and ii qualitative relative hazard zonation of large slow landslides based on the identification of segments characterised by different movement rates since only the radar line of sight projection of the displacements can be detected a quantitative exploitation of the ps data is possible only where sufficient ground truth is available in site specific or single landslide investigations the ps data can represent a very useful complementary data source with respect to the information acquired through ground based observations and in situ surveying however the difficulties associated with the feasibility assessments of the applicability of sar data to local scale problems as well as with the interpretation of ps results require a close collaboration between landslide experts and specialists in advanced processing of radar satellite data the interpretation of the exact geotechnical significance of small radar sensed ground surface deformations is challenging especially where ground truth is lacking although any ground deformation is potentially of interest to an engineering geologist detection of movements in both vertical and horizontal directions is needed in the case of landslides to evaluate slope failure mechanisms with their high radar viewing angles however the current space borne systems can detect only a fraction of the horizontal component of movement it is expected that the upcoming sar dedicated missions with new sensors and different acquisition geometries combined with the rapid developments in the field of advanced radar data processing will allow a full 3d reconstruction of deformation data and help to further reduce the current limitations of the ps and similar dinsar approaches

ground motion measurement in the lake mead area nevada by differential synthetic aperture radar interferometry time series analysis probing the lithosphere rheological structure 1 we measure ground motion around the lake mead nevada using synthetic aperture radar interferometry the lake water level has fluctuated through time since impoundment in 1935 to quantify the deformation due to water level variations over the past decade and to constrain the crust and mantle rheological parameters in the lake area we analyze 241 interferograms based on 43 ers images acquired between 1992 and 2002 all interferograms have a high coherence due to arid conditions most of them show strong atmospheric artefacts tropospheric phase delays are estimated and corrected for each interferogram by analyzing the phase elevation correlation corrections are validated using data from the era40 global atmospheric reanalysis corrected interferograms are inverted pixel by pixel to solve for the time series of ground motion in the lake area temporal smoothing is added to reduce random atmospheric artefacts the observed deformation is nonlinear in time and spreads over a 50 50 km2 area we observe a 16 mm subsidence between 1995 and 1998 due to an 11 m water level increase followed by an uplift due to the water level drop after 2000 we model the deformation taking into account the loading history of the lake since 1935 a simple elastic model with parameters constrained by seismic wave velocities does not explain the amplitude of the observed motion the two layer viscoelastic model proposed by kaufmann and amelung 2000 with a mantle viscosity of 1018 pa s adjusts well the data amplitude and its spatiotemporal shape

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

landslide deformation monitoring with alos palsar imagery a d insar geomorphological interpretation method the objective of this work is to propose a geomorphologically guided method for the interpretation of l band alos palsar interferograms created by differential interferometric synthetic aperture radar d insar the interferograms are used to estimate the deformation pattern of two rapid and large landslides poche la valette south east france the wrapped and unwrapped phase values are interpreted for different movement types rotational translational and complex sliding and two ranges of surface displacement rates kinematic sub units are detected for both landslides and zones affected by enlargement or retrogression are identified the insar derived displacement rates are consistent with ground based measurements and with remote estimates of the displacement from c band and x band satellite sar sensors the results demonstrate the potential of l band alos palsar imagery for the monitoring of active landslides with important changes in the soil surface state and covered by vegetation

persistent scatterer selection using maximum likelihood estimation 1 we present here a new insar persistent scatterer selection method using maximum likelihood estimation to identify persistent scattering pixels which results in a denser network of reliable phase measurements than do existing methods we analyze the phase of each pixel in a series of interferograms and estimate the relative strength of any slowly fluctuating component of the radar echo from a dominant scatterer to the background scattering within a pixel we find a fairly dense network of scatterers with stable phase characteristics in areas where conventional insar fails due to decorrelation we examined data over two vegetated regions in the san francisco bay area the average phases of these pixels clearly show the slip along the hayward fault and set upper bounds on any slip along the bay area segment of the san andreas fault

integrated geophysical imaging of a concealed mineral deposit a case study of the world class pebble porphyry deposit in southwestern alaska abstractwe combined aeromagnetic induced polarization magnetotelluric and gravity surveys as well as drillhole geologic alteration magnetic susceptibility and density data for exploration and characterization of the cu au mo pebble porphyry deposit this undeveloped deposit is almost completely concealed by postmineralization sedimentary and volcanic rocks presenting an exploration challenge individual geophysical methods primarily assist regional characterization positive chargeability and conductivity anomalies are observed over a broad region surrounding the deposit likely representing sulfide minerals that accumulated during multiple stages of hydrothermal alteration the mineralized area occupies only a small part of the chargeability anomaly because sulfide precipitation was not unique to the deposit and mafic rocks also exhibit strong chargeability conductivity anomalies similarly reflect widespread sulfides as well as water saturated glacial sediments mineralogical and magnetic suscep

correlation of satellite image time series for the detection and monitoring of slow moving landslides abstract slow moving landslides are widespread in many landscapes with significant impacts on the topographic relief sediment transfer and human settlements their area wide mapping and monitoring in mountainous terrain however is still challenging the growing archives of optical remote sensing images offer great potential for the operational detection and monitoring of surface motion in such areas this study proposes a multiple pairwise image correlation mpic technique to obtain a series of redundant horizontal displacement fields and different multi temporal indicators for a more accurate detection and quantification of surface displacement the technique is developed and tested on a series of monoscopic and stereoscopic pleiades satellite images at a test site in the south french alps empirical tests confirm that mpic significantly increased detection accuracy f measure 0 85 and that the measurement error can be reduced by averaging velocities from all pair combinations covering a given time step i e when stereo pairs are available for at least one date the derived inventory and displacement fields of 169 slow moving landslides show a positive relationship between the landslide size and velocities as well as a seasonal acceleration of the largest landslides in response to an increase in effective precipitation the processing technique can be adapted to better exploit increasingly available time series from a variety of optical satellites for the detection and monitoring of landslide displacement

transferability of a calibrated numerical model of rock avalanche run out application to 20 rock avalanches on the nuussuaq peninsula west greenland long run out rock avalanches are one of the most hazardous geomorphic processes and risk assessments of the potential threat they pose are often reliant on numerical modelling of their potential run out distance the development of such models requires a thorough understanding of past flow behaviour inferred from deposits emplaced by previous events despite this few records exist of multiple rock avalanches that occurred in conditions sufficiently consistent to develop a set of more generalised and hence transferrable rules we conduct field and imagery based mapping and use numerical modelling to investigate the emplacement of 20 adjacent rock avalanches on the southern flanks of the nuussuaq peninsula west greenland the rock avalanches run out towards the vaigat strait and are sourced from a range of coastal mountains of relatively uniform geology we calibrate a three dimensional continuum dynamic flow code volcflow with data from a modern well constrained event that occurred at paatuut ad 2000 the best fit model assumes a constant retarding stress with a collisional stress coefficient simulating run out to within 0 3 of that observed this calibration was then used to model the emplacement of deposits from five other neighbouring rock avalanches before simulating the general characteristics of a further 14 rock avalanche deposits on simplified topography our findings illustrate that a single calibration of volcflow can account for the observed deposit morphology of a uniquely large collection of rock avalanche deposits emplaced by a series of events spanning a large volume range although the prevailing approach of tuning models to a specific case may be useful for detailed back analysis of that event we show that more generally applied models even using a single pair of rheological parameters can be used to model potential rock avalanches of varied volumes in a region and therefore to assess the risks that they pose

the historical development of the magnetic method in exploration the magnetic method perhaps the oldest of geophysical exploration techniques blossomed after the advent of airborne surveys in world war ii with improvements in instrumentation navigation and platform compensation it is now possible to map the entire crustal section at a variety of scales from strongly magnetic basement at regional scale to weakly magnetic sedimentary contacts at local scale methods of data filtering display and interpretation have also advanced especially with the availability of low cost high performance personal computers and color raster graphics the magnetic method is the primary exploration tool in the search for minerals in other arenas the magnetic method has evolved from its sole use for mapping basement structure to include a wide range of new applications such as locating intrasedimentary faults defining subtle lithologic contacts mapping salt domes in weakly magnetic sediments and better defining targets through 3d inversion these new applications have increased the method s utility in all realms of exploration in the search for minerals oil and gas geothermal resources and groundwater and for a variety of other purposes such as natural hazards assessment mapping impact structures and engineering and environmental studies

visualizing and interpreting surface displacement patterns on unstable slopes using multi geometry satellite sar interferometry 2d insar abstract it is well known that satellite radar interferometry insar is capable of measuring surface displacement with a typical accuracy on the order of millimeters to centimeters however when the true deformation vector differs from the satellite line of sight los the sensitivity decreases and interpretation of insar deformation measurements becomes challenging by combining displacement data from extensive ascending and descending terrasar x datasets collected during the summer seasons of 2009 2014 we estimate two dimensional 2d insar surface displacement displacement data are decomposed into vertical and west east deformation dip and combined deformation vector and validated using global navigation satellite system gnss data we use the decomposed dataset to visualize variations in surface velocity and direction on unstable slopes in a periglacial environment with sporadic permafrost in northern norway by identifying areas with uplift and subsidence and detecting velocity changes downslope acceleration deceleration and related areas of extension and compression we are able to explain driving and controlling mechanisms and geomorphology in two rockslides and one area with solifluction landforms

numerical modeling of an estuary a comprehensive skill assessment i numerical simulations of the hudson river estuary using a terrain following three dimensional model regional ocean modeling system roms are compared with an extensive set of time series and spatially resolved measurements over a 43 day period with large variations in tidal forcing and river discharge the model is particularly effective at reproducing the observed temporal variations in both the salinity and current structure including tidal spring neap and river discharge induced variability large observed variations in stratification between neap and spring tides are captured qualitatively and quantitatively by the model the observed structure and variations of the longitudinal salinity gradient are also well reproduced the most notable discrepancy between the model and the data is in the vertical salinity structure while the surface to bottom salinity difference is well reproduced the stratification in the model tends to extend all the way to the water surface whereas the observations indicate a distinct pycnocline and a surface mixed layer because the southern boundary condition is located near the mouth the estuary the salinity within the domain is particularly sensitive to the specification of salinity at the boundary a boundary condition for the horizontal salinity gradient based on the local value of salinity is developed to incorporate physical processes beyond the open boundary not resolved by the model model results are sensitive to the specification of the bottom roughness length and vertical stability functions insofar as they influence the intensity of vertical mixing the results only varied slightly between different turbulence closure methods of k e k and k kl

physical processes controlling the formation evolution and perturbation of the low salinity front in the inner shelf off the southeastern united states a modeling study physical processes that control the formation evolution and perturbation of the low salinity front over the inner shelf of the south atlantic bight have been examined using a fully three dimensional primitive equation and turbulent closure model the model was forced by semidiurnal tides m2 s2 and n2 climatological means of multiple river discharges and upwelling favorable wind this model has provided a reasonable simulation of the fortnightly and monthly variations of semidiurnal tides computed amplitudes and phases of tides show good agreement with observational data available at tidal gauge stations along the coast spatial structures of buoyancy currents are significantly modified by stratified tidal rectification as a result the southward residual current intensifies significantly at the front and reduces or reverses close to the coast a weak velocity area forms in the downstream region of each river which blocks the low salinity water to form multiple tongue like domes in the inner shelf for a given springtime climatological upwelling favorable wind isolated low salinity lenses can form episodically in two steps at first a geometrically controlling wave like frontal shape develops at the outer edge of the frontal zone as a result of the interaction between tides multiple river discharges and upwelling favorable wind then isolated low salinity lenses form at the crest when water on the shoreward side of the crest is displaced by relatively high salinity water advected from the upstream trough south of the crest and diffused upward from the deeper region wind induced upwelling is noticeable to compensate for the water loss due to the near surface offshore ekman transport but it does not play a critical role in the formation of isolated lenses under the climatological conditions of river discharges and upwelling favorable winds over the inner shelf of the south atlantic bight

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