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

monitoring landslide displacements by using ground based synthetic aperture radar interferometry application to the ruinon landslide in the italian alps 1 synthetic aperture radar sar data are collected by a ground based radar system forming the synthetic aperture by the sliding of the antennas on a linear rail coherent sar processing converts the raw data into a complex image the phase of each image pixel contains information on the target sensor distance and can be exploited as a ranging tool the interferometric technique based on the comparison between paired and coherent sar images taken at different times permits the quantitative extraction of this information thus allowing the monitoring of the morphological changes the portable device used in this application was developed by the joint research center ispra italy specifically for measurements in the field it is known as linear sar and it is able to provide 17 ghz measurements with a 2 8 m synthetic aperture a measurement campaign lasting about 1 week was performed between july and august 2000 for monitoring superficial displacements at the ruinon landslide a 30 million m3 rockslide in the italian alps two sequences of interferograms are presented and discussed the interpretation of the sequences has allowed us to derive multitemporal deformation maps of the test area thus showing the entire displacement field of those landslide sectors characterized by higher radar reflectivity and coherence displacement rates up to 1 2 mm h 1 have been measured with a pixel resolution of 5 m and a measurement precision of 0 75 mm the results have been validated by using ground truth data obtained through automatic extensometers and topographic measurements discrepancies are limited to a few millimeters

erosional power in the swiss alps characterization of slope failure in the illgraben landslides and rockfalls are key geomorphic processes in mountain basins their quantification and characterization are critical for understanding the processes of slope failure and their contributions to erosion and landscape evolution we used digital photogrammetry to produce a multi temporal record of erosion 1963 2005 of a rock slope at the head of the illgraben a very active catchment prone to debris flows in switzerland slope failures affect 70 of the study slope and erode the slope at an average rate of 0 39 0 03 m yr the analysis of individual slope failures yielded an inventory of 2500 failures ranging over 6 orders of magnitude in volume despite the small slope area and short study period the slope failures form a characteristic magnitude frequency distribution with a rollover and a power law tail between 200 m and 1 6 106 m with an exponent of 1 65 slope failure volume scales with area as a power law with an exponent of 1 1 both values are low for studies of bedrock landslides and rockfall and result from the highly fractured and weathered state of the quartzitic bedrock our data suggest that the magnitude frequency distribution is the result of two separate slope failure processes type 1 failures are frequent small slides and slumps within the weathered layer of highly fractured rock and loose sediment and make up the rollover type 2 failures are less frequent and larger rockslides and rockfalls within the internal bedded and fractured slope along pre determined potential failure surfaces and make up the power law tail rockslides and rockfalls of high magnitude and relatively low frequency make up 99 of the total failure volume and are thus responsible for the high erosion rate they are also significant in the context of landscape evolution as they occur on slopes above 45 and limit the relief of the slope copyright 2012 john wiley sons ltd

natural hazards extreme events and mountain topography the hazard of any natural process can be expressed as a function of its magnitude and the annual probability of its occurrence in a particular region here we expand on the hypothesis that natural hazards have size frequency relationships that in parts resemble inverse power laws we illustrate that these trends apply to extremely large events such as mega landslides huge volcanic debris avalanches and outburst flows from failures of natural dams we review quantitative evidence that supports the important contribution of extreme events to landscape development in mountains throughout the world and propose that their common underreporting in the quaternary record may lead to substantial underestimates of mean process rates we find that magnitude frequency relationships provide a link between quaternary science and natural hazard research with a degree of synergism and societal importance that neither discipline alone can deliver quaternary geomorphology stratigraphy and geochronology allow the reconstruction of times magnitudes and frequencies of extreme events whereas natural hazard research raises public awareness of the importance of reconstructing events that have not happened historically but have the potential to cause extreme destruction and loss of life in the future

landslide movement in southwest colorado triggered by atmospheric tides the slumgullion landslide in the western united states has been moving almost continuously for over 100 years observations and numerical modelling show that air pressure changes from atmospheric tides trigger daily movement

recent advances in sar interferometry time series analysis for measuring crustal deformation abstract synthetic aperture radar sar interferometry is a technique that permits remote detection of deformation at the earth s surface and has been used extensively to measure displacements associated with earthquakes volcanic activity and many other crustal deformation phenomena analysis of a time series of sar images extends the area where interferometry can be successfully applied and also allows detection of smaller displacements through the reduction of error sources here we review recent advances in time series sar interferometry methods that further improve accuracy this is particularly important when constraining displacements due to processes with low strain rates such as interseismic deformation we include examples of improved algorithms applied to image deformation associated with the 2010 eruption of eyjafjallajokull volcano in iceland slow slip on the guerrero subduction zone in mexico and tectonic deformation in western anatolia turkey

high resolution displacement monitoring of a slow velocity landslide using ground based radar interferometry abstract ground based interferometric radar gbir monitoring was conducted on a slow moving translational failure landslide in granby grand county colorado usa radar monitoring was completed over two separate surveys in 2011 using a tripod mounted real aperture sensor the purpose of this work is to evaluate gbir as a temporally dense monitoring technique for monitoring landslide displacement and compare the monitoring results to ongoing gps based surveying methods to verify measured displacements we discuss the strengths and limitations of gbir displacement monitoring with a variety of available sensors and place this monitoring platform sensor and workflow into context of previous slope stability monitoring with gbir for both surveys displacement time series were created through a small temporal baseline stacking to reduce noise and maintain high temporal resolution the results of the displacement time series were compared to average displacement rates derived from gps based surveying an overall verification of radar and gps derived displacement rates was achieved and identifies important differences relating to the precision and uncertainty of the two techniques this work demonstrates gbir monitoring capability of establishing high temporal resolution on tracking variable rates of landslide movements spatial modeling of total observed displacements was completed for both surveys verifying a conceptual model of uniform translational landslide movement providing greater confidence for mitigation planning

structurally controlled instability damage and slope failure in a porphyry rock mass abstract rock slopes fail through structurally controlled mechanisms global circular failures or complex mechanisms depending on structural patterns and rock mass damage here structural geology rock mass characterisation terrestrial laser scanning tls ground based radar interferometry gb insar and finite element modelling are integrated to explore relationships between structure damage and global slope failure at mt gorsa trentino italy there a porphyry quarry has been excavated in complex strongly anisotropic rhyolitic ignimbrite rock masses the slope was affected by a major rockslide in 2003 and undergoes continuing instability site investigations and gb insar monitoring revealed that the 2003 failure was a roto translational rockslide involving about 400 000 m3 of disrupted rock structural analysis of tls and field data shows that the slope is affected by widespread structurally controlled mechanisms sliding toppling strain localization in kink bands the non obvious relationships between structurally controlled and global roto translational slope failure mechanisms are investigated by characterising rock mass damage in different slope sectors a new approach to quantify rock mass damage by mapping the geological strength index and interpreting its topographic signatures in tls point clouds is presented a persistent geological marker is systematically mapped in tls point clouds and correlations between attitude variability statistics and rock mass damage are established providing an efficient assessment tool rock mass damage increases in kinematic domains affected by structurally controlled instability gsi 35 40 and is maximum in areas of ongoing global instability gsi 15 20 the 2003 rockslide occurred inside a damaged rock mass zone with gsi

using dinsar airborne lidar and archival air photos to quantify landsliding and sediment transport 1 we demonstrate the ability of coupled remote sensing tools to characterize large slow moving landslides in the eel river catchment northern california from a stack of alos interferograms we identified 5 large 1 km long landslides that exhibited significant activity from february 2007 to february 2008 for the boulder creek earthflow we used orthorectified air photos taken in 1964 and unfiltered airborne lidar flown in 2006 to map the displacement of trees growing on the landslide surface combining those displacement orientations with stacked dinsar data we observed average downslope velocities of 0 65 m yr 1 through the central transport zone of the landslide given landslide depth estimates minimum sediment transport and denudation rates are estimated to be 4100 m3 yr 1 and 1 6 mm yr 1 respectively our results demonstrate the highly erosive role of large slow moving landslides in landscape evolution and suggest that the superposition of dense ephemeral gully networks and rapidly moving zones within the landslide may facilitate delivery of slide mobilized sediment into adjacent fluvial channels

flank instability of stromboli volcano aeolian islands southern italy integration of gb insar and geomorphological observations abstract stromboli is characterized by frequent explosions of variable energy and periodically interrupted by more energetic blasts emitting large volumes of material the pressurization of a volatile poor high porphyritic magma column that is gas recharged by the deep seated volatile rich low porphyritic magma precedes such events and produces deformations on the nw flank of the volcano sciara del fuoco by integrating geomorphological observations with long term displacements from ground based interferometric radar since december 2007 we identified two landslides whose movements are strongly related with volcanic activity movement patterns obtained through a novel long term analysis of gb insar data permitted us to hypothesize the type of movement and depth for both landslides furthermore their position allowed us to affirm that the effusive vent formed in 2007 at 400 m a s l was the result of the deflection of a feeder dike caused by landslide fractures thus showing the important role of geomorphological discontinuities in volcanic environments

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

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

integration of advanced monitoring and numerical modeling techniques for the complete risk scenario analysis of rockslides the case of mt beni florence italy on december 28 2002 a landslide occurred on the eastern flank of mt beni florence italy on a slope where jointed basalts and ophiolitic breccias overlie mesozoic limestones calcari a calpionelle formation the collapse was preceded by several forewarning signals the evolution of the slope deformation was the most important of them and its analysis was the starting point for a risk scenario assessment in fact during the management of the emergency period which began on april 13 2002 in effort to evaluate the actual extension of the landslide the distribution of the displacements within the mass its kinematical characteristics and its spatial and temporal evolution data obtained by means of geomechanical surveys laboratory analyses geotechnical investigations geophysical surveys seismic and gbinsar monitoring systems distometric and automatic and distinct element numerical modeling were integrated thus it has been possible to provide public authorities with all necessary information to plan suitable measures for risk management and reduction after the event the study was completed with a runout back analysis that highlighted successes and failures of the predictive investigations

an examination of seasonal deformation at the portuguese bend landslide southern california using radar interferometry 1 the portuguese bend landslide located on the palos verdes peninsula in southern california is a slow moving landslide whose activity is closely tied to infiltration from rainfall we use radar interferometry to constrain the seasonal kinematics of the landslide from 1995 to 2000 traditional interferometric synthetic aperture radar methods estimate an average downslope displacement rate of 1 00 m yr with an uncertainty range of 0 39 2 57 m yr during the summer months interferograms show a consistent loss in phase coherence over the landslide for epochs greater than 6 months especially in the winter interferograms become incoherent as a result of large displacement and decorrelation is used to map the spatial extent of slide movement through time the displacement rate increases sharply several weeks after the beginning of the rainy season as rainwater percolating into the slide elevates pore pressures phase coherence is lost when the slide velocity surpasses 2 6 m yr for interferograms with durations of a few months a physically based model based on rainfall driven landslide movement incorporates these observations to constrain hydraulic diffusivity to between 0 9 and 3 5 10 6 m2 yr

short term surface ice motion variations measured with a ground based portable real aperture radar interferometer we report measurements using a portable real aperture radar gamma portable radar interferometer gpri for interferometric imaging of the surface ice motion on gornergletscher switzerland during the drainage of the adjacent ice marginal lake gornersee the gpri tracked the surface ice motion in line of sight over an area of 3k m 2 down glacier of gornersee almost continuously during the drainage event the displacement maps derived from the acquired interferograms capture the spatial distribution of the surface ice motion due to fast acquisition times of the microwave images the gpri was able to record sub daily variations of the ice displacements most likely caused by the impact of the gornersee drainage on the ice motion of gornergletscher in situ point measurements of the ice displacement agree reasonably well with the results obtained by the gpri and highlight the use of the gpri for high resolution measurements of glacier surface ice motion motion of gornergletscher these variations in surface ice motion were triggered by the subglacial drainage of the adjacent marginal ice dammed lake gornersee we present ice displacement maps derived from the gpri interfero grams and analyze the performance of the radar device for remote sensing of surface ice motions of a glacier on spatial and temporal scales lower than in conventional d insar applications we compare the radar displacements against local in situ ice displacement measurements to complete the study a brief discussion of the observed displacements in relation to the drainage phenomena is given

monitoring of the beauregard landslide aosta valley italy using advanced and conventional techniques abstract an advanced monitoring technique based on radar interferometry and implemented by using a ground based instrumentation gbinsar has been applied for monitoring the beauregard deep seated gravitational slope deformation this landslide is located in the aosta valley on the dora di valgrisenche river in northwestern italy and impinges on a 132 m high concrete arch gravity dam this is recognized to have relevant implications in terms of civil protection and poses important territorial and environmental issues the poor rock mass conditions of the left abutment slope were reported in the fifties during dam construction since 2002 additional geological hydrogeological and geotechnical investigations have underlined the presence of a deep seated shear zone up to 20 m thick at the landslide toe continuous conventional monitoring over a time span of more than 50 years of both the slope and the dam has allowed to gain insights into the understanding of the behaviour of the basal portion of the slope with very limited and uncertain point wise displacement monitored in the upper sector the gbinsar monitoring technique has allowed to obtain multi temporal surface deformations of the upper portion of the landslide discovering the presence of a main sector in motion previously unknown characterized by a total displacement of 45 mm over 4 months the results of radar monitoring have been validated by comparing with topographic measurements carried out by an automatic total station on 4 targets located at the toe of the slope

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

temporal analysis of a landslide by means of a ground based sar interferometer a ground based synthetic aperture radar gb sar interferometer is used to retrieve the velocity field of a landslide high resolution images are obtained by means of a time domain sar processor an in depth analysis of the sequence of sar interferograms enables the recognition of a slowly deforming upper scarp in the scene and a debris flow that feeds the accumulation zone of the landslide where a fast change in terrain morphology is observed the estimated deformation map is in agreement with the available measurements obtained by means of global positioning system receivers results show that gb sar interferometry is a cost effective solution for the monitoring of landslides the proposed method is shown to be a valid complement to space and airborne sar and to the traditional geodetic instruments

mobile element analysis by secondary ion mass spectrometry sims of impactite matrix samples from the yaxcopoil 1 drill core in the chicxulub impact structure the concentrations of the fluid mobile trace elements lithium beryllium boron and barium were measured in samples of the altered matrix of several impactite breccias of the yaxcopoil 1 drill core using secondary ion mass spectrometry sims to determine the extent of transport due to aqueous or hydrothermal processes three of the elements li be and b have higher concentrations in the upper suevite impact breccias than in the lower impact melt deposits by factors of 3 5 2 2 and 1 5 respectively lithium and b are the most enriched elements up section and appear to have had the greatest mobility the similar fractionation of li and b is consistent with fluid transport and alteration under low temperature conditions of less than 150 c based on published experimental studies in contrast to li be and b the concentration of ba in the altered matrix materials decreases upward in the section and the concentration of ba in the matrix is an order of magnitude less than the bulk concentrations likely due to the presence of barite the origin of the elemental variations with depth may be related to different protolith compositions in the upper versus the lower impactite units a different protolith in the altered matrix is suggested by the mg rich composition of the lower units versus the al rich composition of the upper units which largely correlates with the mobile element variations the possibility that vertical transport of mobile elements is due to a postimpact hydrothermal system is supported by published data showing that the sediments immediately overlying the impactites are enriched in mobile elements derived from a hydrothermal system however the mobile elements in the sediments do not have to originate from the underlying impactites in conclusion our data suggests that the impactites at this location did not experience extensive high temperature hydrothermal processing and that only limited transport of some elements including li be and b occurred

mjo related oceanic kelvin waves and the enso cycle a study with the ncep global ocean data assimilation system 1 the surface wind anomalies associated with the madden julian oscillation mjo appear to play a critical role during the onset and termination phases of enso the characteristics of the mjo related oceanic kelvin waves have not been systematically studied due to a lack of ocean reanalysis that resolves intraseasonal variability this study uses the operational ocean reanalysis for the period 1982 2003 produced by the state of art global ocean data assimilation system at ncep to explore the relationship between sst anomalies of enso and mjo related oceanic kelvin waves the first four extended empirical orthogonal functions of the depth of 20c isotherm are used to represent the dominant oceanic kelvin waves the wave activity is measured by seasonal variance of oceanic kelvin waves svkw at 130w svkw peaks are associated with the onset stage of warm enso events since they occur during the transition period and tend to produce positive tendency in nino3 4 and heat content and lead mature phases by 5 11 months mjo related oceanic kelvin wave activity is also shown to impact the growth and termination of warm events the consistent relationships do not occur in cold events a real time monitoring tool using svkw index is proposed to support the official enso forecast at ncep citation seo k h and y xue 2005 mjo related oceanic kelvin waves and the enso cycle a study with the ncep global ocean data assimilation system geophys res lett 32 l07712 doi 10 1029 2005gl022511

on the application of sar interferometry to geomorphological studies estimation of landform attributes and mass movements this paper presents two examples of application of synthetic aperture radar sar interferometry insar to typical geomorphological problems the principles of insar are introduced taking care to clarify the limits and the potential of this technique for geomorphological studies the application of insar to the quantification of landform attributes such as the slope and to the estimation of landform variations is investigated two case studies are presented a first case study focuses on the problem of measuring landform attributes by interferometric sar data the interferometric result is compared with the corresponding one obtained by a digital elevation model dem in the second case study the use of insar for the estimation of landform variations caused by a landslide is detailed

atmospheric limitations to repeat track radar interferometry in its recent radar imaging mission the shuttle imaging radar satellite sir c devoted three days to repeat track interferometry we have analyzed the data from a test site in the mojave desert of california although good topography 10 m on 21 m postings was obtained most of the error was caused by turbulent water vapor in the lower atmosphere spatial structure of 6 km and all smaller sizes was observed the rms one way time delay was found to be 0 24 cm essentially identical results were obtained at two wavelengths 24 and 5 7 cm

a landslide forecasting model using ground based sar data the portalet case study this paper presents a kinematic study of the portalet landslide sallent de gallego central spanish pyrenees which was triggered by the construction of a big parking area at the toe of the slope a description of the landslide from a geomorphological point of view is first introduced the measurements of displacement performed by conventional total station inclinometers and differential gps and advanced gb sar ground monitoring techniques are presented and gb sar and dgps datasets are compared the correlation between measured displacements and rainfall series indicates that the landslide is very sensitive to rainfall the continuous gb sar measurements from the 5th of october 2006 to the 21st of november 2006 at a rate of 1 h were used to calibrate a simple 1d infinite model by back analysis the model includes a viscoplastic behaviour and takes into account directly the known daily rainfall intensity and the dissipation of the excess pore fluid through a simple consolidation equation prediction was made in an extended period of time from may 2006 to july 2007 and compared to the dgps measurements

three dimensional glacial flow and surface elevation measured with radar interferometry outlet glaciers which serve to drain ice from ice sheets seem to be dynamically less stable in north greenland than in south greenland1 2 3 storstrommen a large outlet glacier in northeastern greenland which surged between 1978 and 1984 ref 2 has been well studied in general neither glacier surge mechanisms nor the geographical distribution of the surges are well known conventional satellite radar interferometry can provide large scale topography models with high resolution4 and can measure the radar line of sight component of ice flow vectors5 but cannot map full vector flow fields here we present an interferometry method that combines observations from descending and ascending satellite orbits which assuming ice flow parallel to the topographic surface allows us to use the differing view angles to estimate full three dimensional surface flow patterns the accuracy of our technique is confirmed by the good agreement between our radar based flow model and in situ global positioning system gps reference data at storstrommen radar measurements such as these made regularly and at high spatial density have the potential to substantially enhance our understanding of glacier dynamics and ice sheet flow as well as improve the accuracy of glacier mass balance estimates

sediment flux from a mountain belt derived by landslide mapping in humid uplands landsliding is the dominant mass wasting process in the western southern alps of new zealand landslides are scale invariant and have a power law magnitude frequency distribution independent studies from other regions suggest that this is a general property of landsliding this observation is of critical importance to the evaluation of the impact of events of different length scales over different time intervals on landscape evolution it is particularly useful when estimating regional geomorphic rates because it constrains the frequency and overall significance of extreme events which cannot otherwise be evaluated by integrating the complete response of the system we estimate the regional denudation rate due to landsliding to be 9 4 mm yr 1 sediment discharge from the western southern alps is dominated by landslide derived material

terrestrial laser scanning in geology data acquisition processing and accuracy considerations terrestrial laser scanning or lidar is a recent innovation in spatial information data acquisition which allows geological outcrops to be digitally captured with unprecedented resolution and accuracy with point precisions and spacing of the order of a few centimetres an enhanced quantitative element can now be added to geological fieldwork and analysis opening up new lines of investigation at a variety of scales in all areas of field based geology integration with metric imagery allows 3d photorealistic models to be created for interpretation visualization and education however gaining meaningful results from lidar scans requires more than simply acquiring raw point data surveys require planning and typically a large amount of post processing time the contribution of this paper is to provide a more detailed insight into the technology data collection and utilization techniques than is currently available the paper focuses on the workflow for using lidar data from the choice of field area and survey planning to acquiring and processing data and finally extracting geologically useful data because manufacturer specifications for point precision are often optimistic when applied to real world outcrops the error sources associated with lidar data and the implications of them propagating through the processing chain are also discussed

surface displacements and surface age estimates for creeping slope landforms in northern and eastern iceland using digital photogrammetry abstract in this study three areas of different active coarse debris slope processes are investigated in northern and eastern iceland surface displacement of some glacier derived rock glaciers and a debris covered glacier in the holar area a moving debris accumulation close to siglufjor ur and a debris layer in sey isfjor ur are measured the displacement fields are obtained by cross correlation matching of multi temporal orthophotos orthophotos are generated using a z i imaging digital photogrammetric workstation and various series of air photos from 1964 to 1994 cross correlation matching is done with the cias software the results are analyzed and used for rough surface age estimates in addition type and cause of movement are discussed the velocity of the debris covered glacier and the rock glaciers in the holar area averages from 0 14 to 0 67 m a 1 the debris accumulation at almenningsnof close to siglufjor ur shows an average displacement of 0 19 m a 1 with a maximum value of 0 84 m a 1 the displacements at almenningsnof agree well with displacements surveyed by gps by the icelandic road authorities the measured velocities in sey isfjor ur although using air photos taken 30 years apart turned out not to be significant but the homogenous direction of the displacement vectors suggests that the debris is currently creeping based on the surface age results all the landforms in holar are suggested to have developed during the late holocene cooling period with ages from around 1500 and 3000 to around 5000 years for the different landforms these surface age estimates coincide with data from moraine datings nearby and holocene climatic development in the north atlantic region

a review of terrestrial radar interferometry for measuring surface change in the geosciences this paper presents a review of the current state of the art in the use of terrestrial radar interferometry for the detection of surface changes related to mass movement different hardware types and acquisition concepts are described which use either real or synthetic aperture for radar image formation we present approaches for data processing procedures paying special attention to the separation of high resolution displacement information from atmospheric phase variations recent case studies are used to illustrate applications in terrestrial radar interferometry for change detection applications range from detection and quantification of very slow moving millimeters to centimeters per year displacements in rock walls from repeat monitoring to rapid processes resulting in fast displacements 50 m yr acquired during single measurement campaigns with durations of only a few hours fast and episodic acting processes such as rockfall and snow avalanches can be assessed qualitatively in the spatial domain by mapping decorrelation caused by those processes a concluding guide to best practice outlines the necessary preconditions that have to be fulfilled for successful application of the technique as well as in areas characterized by rapid decorrelation empirical data from a ku band sensor show the range of temporal decorrelation of different surfaces after more than two years for rock surfaces and after a few seconds to minutes in vegetated areas during windy conditions the examples show that the displacement field can be measured for landslides in dense grassland ice surfaces on flowing glaciers and snowpack creep copyright 2014 john wiley sons ltd

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

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

straightforward reconstruction of 3d surfaces and topography with a camera accuracy and geoscience application topographic measurements for detailed studies of processes such as erosion or mass movement are usually acquired by expensive laser scanners or rigorous photogrammetry here we test and use an alternative technique based on freely available computer vision software which allows general geoscientists to easily create accurate 3d models from field photographs taken with a consumer grade camera the approach integrates structure from motion sfm and multi view stereo mvs algorithms and in contrast to traditional photogrammetry techniques it requires little expertise and few control measurements and processing is automated to assess the precision of the results we compare sfm mvs models spanning spatial scales of centimeters a hand sample to kilometers the summit craters of piton de la fournaise volcano with data acquired from laser scanning and formal close range photogrammetry the relative precision ratio achieved by sfm mvs measurement precision observation distance is limited by the straightforward camera calibration model used in the software but generally exceeds 1 1000 i e centimeter level precision over measurement distances of 10s of meters we apply sfm mvs at an intermediate scale to determine erosion rates along a 50 m long coastal cliff seven surveys carried out over a year indicate an average retreat rate of 0 70 0 05 m a 1 sequential erosion maps at 0 05 m grid resolution highlight the spatio temporal variability in the retreat with semivariogram analysis indicating a correlation between volume loss and length scale compared with a laser scanner survey of the same site sfm mvs produced comparable data and reduced data collection time by 80

integrating radar and laser based remote sensing techniques for monitoring structural deformation of archaeological monuments ground based synthetic aperture radar interferometry gbinsar and terrestrial laser scanning tls were purposely integrated to obtain 3d interferometric radar point clouds to facilitate the spatial interpretation of displacements affecting archaeological monuments the paper describes the procedure to implement this integrated approach in the real world situations of surveillance of archaeological and built heritage targeted tests were carried out on the case study of the domus tiberiana sited along the northern side of the palatino hill in the central archaeological area of rome italy and displacements of the monument were monitored over almost one year of acquisition the gbinsar tls integration provided updated information about the condition of the archaeological structures in relation to their history of instability mechanisms and did not highlighted a general worsening for the stability of the entire monument point wise and prompt detection of displacement anomalies and or sudden changes in displacement trends proved the suitability of the method to support early warning procedures also to evaluate effects on the masonry due to human activities