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Aziz, Saeful, Christian Natanael Simamora, Ida Wayan Supriharta, and Rahmantha Purba Anggana. "OPTIMASI PENAMBANGAN BATUBARA MENGGUNAKAN KONTROL SLOPE STABILITY RADAR DI PIT C1 BLOK 8 BINUNGAN MINE OPERATION AREA 2 PT BERAU COAL." Prosiding Temu Profesi Tahunan PERHAPI 1, no. 1 (March 29, 2020): 533–54. http://dx.doi.org/10.36986/ptptp.v1i1.95.
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ABSTRAK Pit C1 Blok 8 Site Binungan Mine Operation Area 2 PT Berau Coal merupakan salah satu area operasional penambangan batubara dengan karakteristik multi-seam, kemiringan lapisan batubara pada interval 12 – 20 derajat, ketebalan lapisan batubara pada interval 0.5 – 7.5 meter, dan variasi ketebalan interburden pada interval 3 – 300 meter. Karakteristik endapan batubara menjadi salah satu pertimbangan dalam pembentukan disain penambangan batubara yang dikolaborasikan dengan disiplin ilmu lain diantaranya geoteknik, hidrologi, safety and environment, dan aspek – aspek lainnya.Geoteknik monitoring and controlling merupakan salah satu aspek penting dalam menjaga kestabilan lereng selama proses pembentukan desain sampai desain tambang terbentuk. Salah satu komitmen PT Berau Coal dalam meningkatkan awareness terhadap isu kestabilan lereng adalah dengan digunaknnya Slope Stability Radar untuk membantu Geoteknik monitoring and controlling secara real time.Salah satu value yang dipegang oleh PT Berau Coal yakni continuous improvement. Didorong oleh semangat dari value tersebut, PT Berau Coal melakukan kajian dan implementasi terkait kemungkinan unit slope stability radar dapat mendukung optimasi penambangan batubara pada area-area final disain. Tujuan improvement ini adalah untuk melakukan optimasi penambangan batubara pada area final dengan menggunakan tambahan kontrol slope stability radar. Area final yang dimaksud spesifik terletak pada blok 85-81 (arah barat-timur) di Pit C1 Blok 8 Site Binungan Mine Operation Area 2 PT Berau Coal. Dalam penelitian ini penulis bersama team yang yang dibentuk (terdiri dari department Mine Planning, Mine Operation, Geoteknik dan Hidrologi) melakukan perencanaan menggunakan siklus plan, do, check, action (PDCA) terkait kelayakan optimasi penambangan batubara menggunakan kontrol slope stability radar dari segi geoteknik, standar operasinal penambangan batubara, dan sistem tanggap darurat. Tahapan optimasi dilakukan dari arah barat (blok besar) menuju timur (blok kecil) dengan support man power yang kompeten dan kontrol dari alat slope stability radar. Hasil improvement ini menunjukan bahwa Optimasi penambangan batubara menggunakan kontrol slope stability radar memberikan kontribusi positif terhadap capaian produksi batubara sebesar 123.204 ton pada SR 6.56. Kata kunci: optimasi penambangan batubara, slope stability radar, sistem tanggap darurat. ABSTRACT Pit C1 Block 8 Site Binungan Mine Operation Area 2 is one of the operational areas of coal mining with multi-seam characteristics, the slope of the coal seam at intervals of 12-20 degrees, the thickness of the coal seam at intervals of 0.5 - 7.5 meters, and variations in interburden thickness at intervals of 3 - 300 meters. The characteristics of coal deposits become one of the considerations in the formation of coal mining designs in collaboration with other scientific disciplines including geotechnical, hydrological, safety and environment, and other aspects.Geotechnical monitoring and controlling is one of the important aspects in maintaining the stability of slopes during the design formation process until the mine design is formed. One of PT Berau Coal's commitments in increasing awareness of the issue of slope stability is the use of the Slope Stability Radar to assist in monitoring and controlling geotechnics in real time.One of the values held by PT Berau Coal is continuous improvement. Encouraged by the spirit of this value, PT Berau Coal conducted a study and implementation related to the possibility that the slope stability radar unit could support the optimization of coal mining in the final design areas. The aim of this improvement is to optimize coal mining in the final area by using additional control of the slope stability radar. The specific final area is located in block 85-81 (west-east direction) in Pit C1 Block 8 PT Berau Coal Mine Operation Area 2 Site. In this study the authors and the team formed (consisting of the Mine Planning, Mine Operation, Geotechnical and Hydrology departments) plan using a cycle plan, do, check, action (PDCA) related to the feasibility of optimizing coal mining using slope stability radar control in terms of geotechnical engineering, coal mining operations standards, and emergency response systems. The optimization stage is carried out from the west (large block) to the east (small block) with competent support of man power and control of the slope stability radar. The results of this improvement show that optimization of coal mining using the slope stability radar control contributes positively to the achievement of coal production of 123,204 tons at SR 6.56. Keywords: coal mining optimization, slope stability radar, emergency response system.
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López-Vinielles, Juan, José A. Fernández-Merodo, Pablo Ezquerro, Juan C. García-Davalillo, Roberto Sarro, Cristina Reyes-Carmona, Anna Barra, et al. "Combining Satellite InSAR, Slope Units and Finite Element Modeling for Stability Analysis in Mining Waste Disposal Areas." Remote Sensing 13, no. 10 (May 20, 2021): 2008. http://dx.doi.org/10.3390/rs13102008.
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Slope failures pose a substantial threat to mining activity due to their destructive potential and high probability of occurrence on steep slopes close to limit equilibrium conditions, which are often found both in open pits and in waste and tailing disposal facilities. The development of slope monitoring and modeling programs usually entails the exploitation of in situ and remote sensing data, together with the application of numerical modeling, and it plays an important role in the definition of prevention and mitigation measures aimed at minimizing the impact of slope failures in mining areas. In this paper, a new methodology is presented; one that combines satellite radar interferometry and 2D finite element modeling for slope stability analysis at a regional scale, and applied within slope unit polygons. Although the literature includes many studies applying radar interferometry and modeling for slope stability analysis, the addition of slope units as input data for radar interferometry and modeling purposes has, to our knowledge, not previously been reported. A former mining area in southeast Spain was studied, and the method proved useful for detecting and characterizing a large number of unstable slopes. Out of the 1959 slope units used for the spatial analysis of the radar interferometry data, 43 were unstable, with varying values of safety factor and landslide size. Out of the 43 active slope units, 21 exhibited line of sight velocities greater than the maximum error obtained through validation analysis (2.5 cm/year). Finally, this work discusses the possibility of using the results of the proposed approach to devise a proxy for landslide hazard. The proposed methodology can help to provide non-expert final users with intelligible, clear, and easily comparable information to analyze slope instabilities in different settings, and not limited to mining areas.
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Dick, Graham J., Erik Eberhardt, Albert G. Cabrejo-Liévano, Doug Stead, and Nick D. Rose. "Development of an early-warning time-of-failure analysis methodology for open-pit mine slopes utilizing ground-based slope stability radar monitoring data." Canadian Geotechnical Journal 52, no. 4 (April 2015): 515–29. http://dx.doi.org/10.1139/cgj-2014-0028.
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The recent introduction of ground-based slope stability radar in open-pit mines to complement conventional geodetic monitoring programs provides near real-time deformation measurements over a broad coverage area; this allows geotechnical engineers to observe the spatial distribution of pit wall movements and their progression over time. This paper presents a newly proposed early warning time-of-failure (TOF) analysis procedure for use in real-time with ground-based radar measurements designed to be integrated in an open-pit mine’s trigger action response plan (TARP). The inverse-velocity and slope gradient (SLO) TOF analysis methods are applied to radar displacement measurements using a new systematic multi-pixel selection technique termed the “percent deformation method.” The utilization of the percent deformation method in the proposed real-time TOF analysis methodology gives more-reliable results than current practice by providing recommendations for pixel selections, data filtering, where and how to undertake TOF analyses, and presenting TOF results in real time. The addition of a more rigorous, methodical treatment of radar monitoring data when faced with critical slope instability will reduce uncertainty and increase confidence in any trigger action response decisions, helping to ensure a safer work environment.
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Lucas, Daisy, Kerstin Fankhauser, Hansruedi Maurer, Brian McArdell, Reto Grob, Ralf Herzog, Ernst Bleiker, and Sarah M. Springman. "Slope Stability of a Scree Slope Based on Integrated Characterisation and Monitoring." Water 12, no. 2 (February 7, 2020): 447. http://dx.doi.org/10.3390/w12020447.
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Three years of geotechnical seasonal field monitoring including soil temperature, suction and volumetric water content plus geophysical measurements, lead to a preliminary ground model and assessment of slope stability for a steep scree slope in the Meretschibach catchment, near Agarn village in the Swiss Alps. Building on data reported in a previous paper, which focused on preliminary ground characterisation and seasonal field monitoring, this current research aims to understand whether a surficial failure in the scree slope, triggered by rainfall and depending on bedrock conditions, would represent a relevant natural hazard for Agarn village. A final year of field data is included as well as site-specific sensor calibration, a Ground Penetrating Radar (GPR) profile, and laboratory triaxial testing to provide strength parameters. A bedrock map is presented, based on GPR, with a realistic ground model of the entire scree slope. Furthermore, a preliminary numerical analysis, performed using SEEP-SLOPE/W, shows the influence of a bedrock outcrop observed in the field, for a specific soil thickness, strength parameters and rain intensity. The stability of a gravelly slope decreases with groundwater flow over a step in the bedrock, and the location of the failure will tend to move uphill of a bedrock outcrop at a shallow depth as groundwater flow increases.
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Cahyo, Fery Andika, Audi Farizka, Ahmad Amiruddin, and Rachmat Hamid Musa. "Practical Method of Predicting Slope Failure Based on Velocity Value (SLO Method) From Slope Stability Radar." Prosiding Temu Profesi Tahunan PERHAPI 1, no. 1 (August 16, 2019): 143–50. http://dx.doi.org/10.36986/ptptp.v0i0.14.
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Predicting slope failure is one of the most sought after feature from Slope Stability Radar (SSR). An accurate slope failure prediction will potentially give an ample time to manage risk related with slope stability, wherein the evacuation ofequipment or personal would be executed on a timely manner. The renownedmethod to predict failure among geo-mechanical practitioner is utilizing inversevelocity method, in which collapse will be predicted to happen when the extension of inverse velocity line is intercepted at predefined value that is usually only fractal above zero. The tenet of this method is, if one has acquired the knowledge of inverse velocity value from previous collapses, the next collapse could be predicted based on it with the pretext that both share the same nature and geological feature. The same can be said for predicting collapse based on velocity value. Set of maximum velocity value from several previous collapses will be averaged to determine predefined assumption to predict the next collapse. This paper will demonstrate an alternative method to predict collapse that will use velocity value instead of inverse velocity. This method is called SLO method as proposed by Azania Mufundirwa.This paper will specifically exemplify the practical steps to produce the failureprediction from slope stability radar data, and discuss the characteristic of theprediction yield by this method. Velocity chart with velocity calculation period of60 minutes is first established from particular pixel deemed as the one that showing the most distinguished progressive deformation trend. The velocity data will then be an exported and reprocess as such that the time data will be converted into unit time stamp number. The designated time stamp will then be accumulated, in which the onset of failure, will be regarded as time 0 reference. Log linear chart will be generated in which X-axis will be occupied by velocity value, while Y-axis will depict Velocity x Accumulated time (SLO chart). Collapse can subsequently be predicted by intercepting the predefined assumption of velocity during collapse with the log linear curve from the SLO chart. Two methods, mathematical & graphical, will be presented in this paper in order to give in depth understanding as to how one can predict collapse event with velocity value. Taking account on the study case from iron ore mining, SLO method yielded prediction of failuretime on 10:58 PM 31st January 2016, meanwhile the real failure occur on 11:32 PM 31st January 2016.
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Guo, Tongsuo, Wei Zhou, Zhaolin Li, Chuanwei Zhang, Qingxiang Cai, Ya Tian, Huairui Qin, Fuming Liu, Izhar Mithal Jiskani, and Dongxu Zhang. "Optimization of Land Saving and Loss Reducing and Slope Stability Variation Patterns in Open-Pit Mine." Geofluids 2021 (April 14, 2021): 1–10. http://dx.doi.org/10.1155/2021/6620235.
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This study presents different land saving and loss reducing schemes. Comprehensively compare the economic benefits of the schemes. It is shown that the optimal scheme can recover tons of coal resources on the south slope, creating significant economic benefits. Numerical simulation was utilized to analyze the changes of slope stability, deformation, and shear strain increment in the process of land saving and loss reducing. Results found that the slope stability decreases rapidly, and the toe of the slope has to be internally discharged in time to compress the slope. Timely follow-up of in-slope rows can improve slope stability. The position of the slope shear exit changes with the increase of the distance of the inner row, and its stability increases gradually. When the distance of the lower inner row exceeds 120 m, the increase of the internal row distance has little influence on the slope stability. When the inner distance exceeds 60 m in the process of internal dumping of upper platform, the position of potential sliding plane gradually changes from the lower dump to the upper and lower dump with the increase of inner dumping distance. It shows that the stability of the dump will be damaged if the upper dump continues to be discharged. Therefore, the distance between the upper and lower dump sites is more important than 60 m. The stability of the south slope is good in the process of mining and internal drainage, and the overall stability of the south slope is controllable, based on slope radar monitoring.
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Kumar, Ajay, and Vasant G. K. Villuri. "Role of Mining Radar in Mine Slope Stability Monitoring at Open Cast Mines." Procedia Earth and Planetary Science 11 (2015): 76–83. http://dx.doi.org/10.1016/j.proeps.2015.06.010.
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Marshall, Hans-Peter, Gary Koh, and Richard R. Forster. "Estimating alpine snowpack properties using FMCW radar." Annals of Glaciology 40 (2005): 157–62. http://dx.doi.org/10.3189/172756405781813500.
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AbstractLarge variations in both snow water equivalent (SWE) and snow slope stability are known to exist in the alpine snowpack, caused by wind, topographic and microclimatic effects. This variability makes extrapolation of point measurements of snowpack properties difficult and prone to error, but these types of measurements are used to estimate SWE and stability across entire mountain ranges. Radar technology provides a promising alternative to point measurements, because large areas can be covered quickly and non-intrusively. There is great potential for obtaining information on a large spatial scale from airborne applications. Frequency-modulated continuous wave (FMCW) radar measurements were made from the ground in several different alpine snowpacks, along with manual and in situ electrical measurements. The surface and ground reflections from the radar data, combined with an average density estimate, can provide a useful estimate of SWE. In addition, the locations of internal reflections are highly correlated with both visually identified layers and measured changes in in situ dielectric properties.
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Jauvin, Matthias, Yajing Yan, Emmanuel Trouvé, Bénédicte Fruneau, Michel Gay, and Blaise Girard. "Integration of Corner Reflectors for the Monitoring of Mountain Glacier Areas with Sentinel-1 Time Series." Remote Sensing 11, no. 8 (April 25, 2019): 988. http://dx.doi.org/10.3390/rs11080988.
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Glacier flow and slope instabilities in Alpine mountain areas represent a hazard issue. Sentinel-1 satellites provide regular Synthetic Aperture Radar (SAR) acquisitions that are potentially useful to monitor these areas, but they can be affected by temporal decorrelation due to rapid changes in the surface. The application of interferometric synthetic aperture radar (InSAR) therefore seems difficult due to loss of coherence. On the other hand, Corner Reflectors (CR) can be used as coherent targets in SAR images for accurate displacement measurement thanks to their strong backscattering property and temporal stability. The use of CRs in multi-temporal InSAR analysis in Alpine mountain areas can thus be beneficial. In this study, we present a comparison between triangular and rectangular CRs, based on Radar Cross Section (RCS) measurements in an anechoic chamber and on long-term experiments over the Argentière glacier and the surrounding slopes and moraine. The visibility in both summer and winter of 10 CRs installed on the test site was investigated. As this area is exposed to heavy precipitation including snow falls, two perforated CRs were tested. The amplitude stability and the phase error of each CR were estimated. A precise tracking of two CRs installed at the glacier surface was also able to measure the displacement of the Argentière glacier, giving results close to previous GPS measurements. Furthermore, a Persistent Scatterer Interferometry (PSI) study was conducted, using the most stable CR as reference point to estimate slope instabilities, which led to the identification of an area corresponding to a tectonic fault called “Faille de l’angle”. The precise absolute locations of the CRs were successfully estimated and PS heights were compared with a LiDAR-based (Light Detection And Ranging) digital elevation model (DEM) and GPS measurements.
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Armaș, Iuliana, Mihaela Gheorghe, and George Cătălin Silvaș. "Shallow Landslides Physically Based Susceptibility Assessment Improvement Using InSAR. Case Study: Carpathian and Subcarpathian Prahova Valley, Romania." Remote Sensing 13, no. 12 (June 18, 2021): 2385. http://dx.doi.org/10.3390/rs13122385.
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A multi-temporal satellite radar interferometry technique is used for deriving the actual surface displacement patterns in a slope environment in Romania, in order to validate and improve a landslide susceptibility map. The probability the occurrence of future events is established using a deterministic approach based on a classical one-dimension infinite slope stability model. The most important geotechnical parameters for slope failure in the proposed study area are cohesion, unit weight and friction angle, and the triggering factor is a rapid rise in groundwater table under wetting conditions. Employing a susceptibility analysis using the physically based model under completely saturated conditions proved to be the most suitable scenario for identifying unstable areas. The kinematic characteristics are assessed by the Small BAseline Subsets (SBAS) interferometry technique applied to C-band synthetic aperture radar (SAR) Sentinel-1 imagery. The analysis was carried out mainly for inhabited areas which present a better backscatter return. The validation revealed that more than 22% of the active landslides identified by InSAR were predicted as unstable areas by the infinite slope model. We propose a refinement of the susceptibility map using the InSAR results for unravelling the danger of the worst-case scenario.
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Deguchi, T., T. Sugiyama, and M. Kishimoto. "R&D OF DRONE-BORNE SAR SYSTEM." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W13 (June 4, 2019): 263–67. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w13-263-2019.
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<p><strong>Abstract.</strong> DInSAR (Differential Interferometric Synthetic Aperture Radar) is already well-known as an effective application technique of SAR data for the displacement measuring of the ground surface. The authors are developing a drone-borne SAR that can apply DInSAR analysis. In Japan, which has suffered various disasters, the slope stability monitoring for active volcanoes, landslide slopes, open-pit mines, etc., and the maintenance management for aging infrastructures are considered important issues. Therefore, by effectively utilizing the position information and terrain information obtained from the satellite data, we have started an R&D project aiming at practical application of DInSAR technology with drone-borne SAR.</p>
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Idhan, Muh Arif, Gina Audina Alhabsyi, and Muhammad Ikbal. "STRUCTURAL GEOLOGY FAULT EFFECT ON HIGHWALL COAL MINING AND FAILURE EVALUATION BASED ON VELOCITY DATA AT BENGALON, EAST-KUTAI DISTRIC, EAST KALIMANTAN PROVINCE." Indonesian Mining Professionals Journal 3, no. 1 (June 29, 2021): 9–16. http://dx.doi.org/10.36986/impj.v3i1.31.
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The geological structure especially folds and faults will reduce slope stability at slope mining where many events are the main factors that trigger slope failure. The geological structure "unknown" is defined as a minor geological structure that was not defined in the initial geological modeling. This uncertainty geological structure is critical issue during the mining process in coal mining. Slope stability Radar is a monitoring instrument that has been used in this research. In SSR data analysis, graphical behavior from velocity data is for monitoring program. The analysis in this research consisted of measuring the geological structure in the area where slope failure occurred and reading the velocity acceleration data from SSR instrument.Slope failure in this research study conduct on the high-wall coal mining which is in line with the geological structure plane with direction N 2460 E and dip 480, along + 150 m and at elevations RL +30 to RL -10. Velocity value at the time of slope failure was 13,568 mm/hour. This value can then be used as a reference as the “Progressive Velocity” value before the slope failure occurs at certain slope wall conditions.The content case study is expected to help engineers in increasing confidence in determining the characteristics of slope failure based on Velocity data in areas that have a geological structure, however, this study research aims to determine basic behavior in the SSR monitoring program and serve as a reference in the risk management program in the coal Mining industry.
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Nico, Giovanni, Sérgio Oliveira, Joao Catalão, and José Zêzere. "Generation of Persistent Scatterers in Non-Urban Areas: The Role of Microwave Scattering Parameters." Geosciences 8, no. 7 (July 23, 2018): 269. http://dx.doi.org/10.3390/geosciences8070269.
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In this work, we study the capability of the ground surface to generate Persistent Scatterers (PS) based on the lithology, slope and aspect angles. These properties affect the scattering behavior of the Synthetic Aperture Radar (SAR) signal, the interferometric phase stability and, as a consequence, the PS generation. Two-time series of interferometric SAR data acquired by two different SAR sensors in the C-band are processed to generate independent PS datasets. The region north of Lisbon, Portugal, characterized by sparse vegetation and lithology diversity, is chosen as study area. The PS frequency distribution is obtained in terms of lithology, slope and aspect angles. This relationship could be useful to estimate the expected PS density in landslide-prone areas, being lithology, slope and aspect angles important landslide predisposing factors.
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Arcone, Steven A., Robert Jacobel, and Gordon Hamilton. "Unconformable stratigraphy in East Antarctica: Part I. Large firn cosets, recrystallized growth, and model evidence for intensified accumulation." Journal of Glaciology 58, no. 208 (2012): 240–52. http://dx.doi.org/10.3189/2012joj11j044.
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AbstractUnconformable firn stratigraphy exists throughout a 650 km long radar profile that we recorded down-flow of megadune fields in the Byrd Glacier (East Antarctica) catchment. Profile segments reveal cosets of prograding bedding sequences up to 90 m thick and with lateral, along-crest dimensions up to tens of kilometers. We profiled them in oblique section and nearly parallel to the prevailing wind. The prograding snow accumulates on broad, low windward slopes located above ice-bed depressions, which implies long-term slope stability. The apparent subglacial control implies that the accumulation progrades in balance with ice velocity, which we measured at ~30 ma”1. The sequences prograde over intensely modified and recrystallized wind-glaze firn, visible in the profiles as unstratified layers and zones up to several tens of meters thick. The intense recrystallization eliminates density stratification, and the altered layers appear to thicken into a connected network. Modeling of coset formation using wind and ice flow reproduces their dimensions and morphology. However, accumulation rates well above current regional estimates and existing data for megadunes are required because of the measured ice speed and required slope stability. The consistent unconformable strata along our traverse show that coset and recrystallized morphology extend far beyond the megadune fields.
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Schröder, Ludwig, Andreas Richter, Denis V. Fedorov, Lutz Eberlein, Evgeny V. Brovkov, Sergey V. Popov, Christoph Knöfel, et al. "Validation of satellite altimetry by kinematic GNSS in central East Antarctica." Cryosphere 11, no. 3 (May 5, 2017): 1111–30. http://dx.doi.org/10.5194/tc-11-1111-2017.
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Abstract. Ice-surface elevation profiles of more than 30 000 km in total length are derived from kinematic GNSS (GPS and the Russian GLONASS) observations on sledge convoy vehicles along traverses between Vostok Station and the East Antarctic coast. These profiles have accuracies between 4 and 9 cm. They are used to validate elevation data sets from both radar and laser satellite altimetry as well as four digital elevation models. A crossover analysis with three different processing versions of Envisat radar altimetry elevation profiles yields a clear preference for the relocation method over the direct method of slope correction and for threshold retrackers over functional fit algorithms. The validation of CryoSat-2 low-resolution mode and SARIn mode data sets documents the progress made from baseline B to C elevation products. ICESat laser altimetry data are demonstrated to be accurate to a few decimetres over a wide range of surface slopes. A crossover adjustment in the region of subglacial Lake Vostok combining ICESat elevation data with our GNSS profiles yields a new set of ICESat laser campaign biases and provides new, independent evidence for the stability of the ice-surface elevation above the lake. The evaluation of the digital elevation models reveals the benefits of combining laser and radar altimetry.
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Wei, Lianhuan, Qiuyue Feng, Feiyue Liu, Yachun Mao, Shanjun Liu, Tianhong Yang, Cristiano Tolomei, Christian Bignami, and Lixin Wu. "Precise Topographic Model Assisted Slope Displacement Retrieval from Small Baseline Subsets Results: Case Study over a High and Steep Mining Slope." Sensors 20, no. 22 (November 21, 2020): 6674. http://dx.doi.org/10.3390/s20226674.
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Due to the intrinsic side-looking geometry of synthetic aperture radar (SAR), time series interferometric SAR is only able to monitor displacements in line-of-sight (LOS) direction, which limits the accuracy of displacement measurement in landslide monitoring. This is because the LOS displacement is only a three dimensional projection of real displacement of a certain ground object. Targeting at this problem, a precise digital elevation model (DEM) assisted slope displacement retrieval method is proposed and applied to a case study over the high and steep slope of the Dagushan open pit mine. In the case study, the precise DEM generated by laser scanning is first used to minimize topographic residuals in small baseline subsets analysis. Then, the LOS displacements are converted to slope direction with assistance of the precise DEM. By comparing with ground measurements, relative root mean square errors (RMSE) of the estimated slope displacements reach approximately 12–13% for the ascending orbit, and 5.4–9.2% for the descending orbit in our study area. In order to validate the experimental results, comparison with microseism monitoring results is also conducted. Moreover, both results have found that the largest slope displacements occur on the slope part, with elevations varying from −138 m to −210 m, which corresponds to the landslide area. Moreover, there is a certain correlation with precipitation, as revealed by the displacement time series. The outcome of this article shows that rock mass structure, lithology, and precipitation are main factors affecting the stability of high and steep mining slopes.
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Paradella, W. R., J. C. Mura, F. F. Gama, A. R. Santos, G. G. Silva, M. Galo, P. O. Camargo, and A. Q. Silva. "COMPLEMENTARY USE OF INFORMATION FROM SPACE-BASED DINSAR AND FIELD MEASURING SYSTEMS FOR OPERATIONAL MONITORING PURPOSES IN OPEN PIT IRON MINES OF CARAJÁS MINING COMPLEX (BRAZILIAN AMAZON REGION)." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-7/W3 (April 30, 2015): 905–11. http://dx.doi.org/10.5194/isprsarchives-xl-7-w3-905-2015.
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Now spanning five simultaneous open-pit operations with exploration carried out through open pit benching, Carajás complex encompasses the world´s largest iron reserves. Open pit mining operations in the area can lead to slope instabilities with risks to personnel, equipment and production due to intense excavations in rock products of low geomechanical quality, blasting practices and heavy precipitation. Thus, an effective prediction and management of surface deformations should be a key concern for the mining operations. The ground displacement monitoring techniques in Carajás include surface measurement techniques at discrete points (total station/reflective prisms) and over area using SSR (Slope Stability Radar, a ground based radar). On the other hand, DInSAR techniques are receiving relevance in the mining industry for reasons such a synoptic and continuous coverage without the need for ground instrumentation and a point-to-point good accuracy of measuring displacements (millimeter to centimeter scale) over a dense grid. Using a stack of 33 StripMap TerraSAR-X images acquired over Carajás covering the time span from March 2012 to April 2013, a monitoring approach is discussed based on the complementary use of information provided by DInSAR (DInSAR Time-Series and Persistent Scatterer Interferometry) and surface measuring techniques (total station/prisms, ground-based radar).
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Zhang, Qiang Yong, Wen Xiang, and Xiao Jing Li. "Application of Nondestructive Detecting Technology for Geological Radar in a Large-Scale Highway Lanslide Treatment." Key Engineering Materials 353-358 (September 2007): 2309–12. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.2309.
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The geological radar is an advanced non-destructive geophysical prospecting technology used in detecting the invisible and abnormal underground objects. In this paper, this technology is used in the large-scale highway landslide treatment. The location and size of the cavity, fissure and fracture zone in the landslide body is identified accurately. The supporting design and reinforcement construction for the landslide is performed according to the testing results, which ensures the slope stability and the normal operation of the highway, and significant economic benefits have been achieved.
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Hartwig, Marcos Eduardo, Leandro Ribes De Lima, and Daniele Perissin. "IW Sentinel-1 satellite scenes for the investigation of mine slope stability: experiences from the Riacho dos Machados gold mine (Brazil)." Earth Sciences Research Journal 25, no. 1 (April 16, 2021): 93–99. http://dx.doi.org/10.15446/esrj.v25n1.86563.
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In the last decade, the Persistent Scatterer Interferometry – PSI have been largely employed to predict instabilities and failure in open pit mines. The PSI is a powerful technique, which combines radar satellite data in order to detect and monitor tiny surface displacements over vast areas. In the last years, the Sentinel-1 radar mission have produced images of the globe acquired with different spatial and temporal resolutions that are now freely available. In recent years, the footwall slopes of the Riacho dos Machados Gold Mine – MRDM (Minas Gerais state, southeastern Brazil) have recorded large planar failures controlled by foliation planes. Therefore, the focus of this paper is to evaluate a stack of 39 Interferometric Wide Sentinel-1 scenes, spanning from January 2018 to April 2019, acquired in descending orbit geometry, for the detection and monitoring of surface displacements in the MRDM. The results have shown that descending IW Sentinel-1 scenes can be used to provide a broad picture of the Line-Of-Sight - LOS deformation phenomena. In order to monitor the evolution of the deformation phenomena induced by mining activities, LOS deformation maps with millimeter accuracy could be only delivered at least each 12 days.
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Kovacik, M., and R. Ondrasic. "The effect of Quaternary uplift on the stability of slopes in the central part the Skorusinske Vrchy mountains in the west Carpathians." Geological Society, London, Engineering Geology Special Publications 7, no. 1 (1991): 659–64. http://dx.doi.org/10.1144/gsl.eng.1991.007.01.66.
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AbstractThe Skorušinské vrchy mountains are part of the West Carpathians in northwest Slovakia near the Polish border. They consist of four Palaeogene sedimentary complexes and comprise a 1500 to 2000 m thick sequence of conglomerates, claystones, flyschoid rocks and sandstones. The older complexes erop out on the margins of the mountains and are covered by relatively thin clayey soils. The central part, the most highly uplifted block, consists of Eocene calcareous sandstone which are disturbed by joints and deep-seated faults. The difference in elevation between the mountain summits and the valley floors is more than 400 m.A detailed investigation of mass movement has been carried out using aerial photographs,air borne radar and satellite imagery foliowed by a field survey.Three main types of slope deformation were identified - rock block slides along bedding surfaces, rock siumps across bedding surfaces and landslides in slope debris. The occurrence of the largest and most deep-seated slides are controlled by faults. The presence of these mass deformations indicate the existence of tilted fault blocks which are the result of neotectonic arch uplift. About 15–17% of the area covered by sandstones is affected by mass movements. This paper describes the methodology of the investigation, the mechanism and genesis of slope deformations, the occurrence and parameters of slides and the role of the Quaternary uplift in the slope instability component of regional geomorphological evolution.
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Theune, Ulrich, Dean Rokosh, Mauricio D. Sacchi, and Douglas R. Schmitt. "Mapping fractures with GPR: A case study from Turtle Mountain." GEOPHYSICS 71, no. 5 (September 2006): B139—B150. http://dx.doi.org/10.1190/1.2335515.
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Ground-penetrating radar (GPR) surveys were acquired of rocks on the highly fractured summit of Turtle Mountain in Canada. In 1903 a disastrous rock slide occurred at Turtle Mountain and it still poses a geologic hazard. Dips, shapes, and penetration depths of fractures are important parameters in slope-stability analysis. Determination of fracture orientation at Turtle Mountain has been based mostly on areal geologic mapping and, most recently, on data collected from boreholes. The purpose of GPR surveys was to test, confirm, and extend information about fractures and bedding planes. Data acquisition was complicated by the rough terrain; because slopes are steep and uneven. This also complicated analysis of the data. Measurement of in situ velocity — an important value for migration — was impossible. Instead, data were migrated with different velocities and data results were chosen that were considered to be reasonable. Analysis and interpretation of the data, resulted in confirmation and extension of the a priori information on orientations of fractures and bedding planes at Turtle Mountain. Despite the rough terrain and highly fractured rock mass, GPR surveys provide reliable information about the shapes and density of fractures — information important for slope-stability evaluation. The most reliable migration results obtained for velocities were considerably less than the standard velocities recorded for limestone, the dominant lithofacies at Turtle Mountain. We interpret this observation as an indicator of water within the rock. However, thorough investigation of this conclusion remains a project for future work.
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Martino, S., and P. Mazzanti. "Integrating geomechanical surveys and remote sensing for sea cliff slope stability analysis: the Mt. Pucci case study (Italy)." Natural Hazards and Earth System Sciences 14, no. 4 (April 11, 2014): 831–48. http://dx.doi.org/10.5194/nhess-14-831-2014.
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Abstract. An integrated approach to the geomechanical characterization of coastal sea cliffs was applied at Mt. Pucci (Gargano promontory, Southern Italy) by performing field-based geomechanical investigations and remote geostructural investigations via a terrestrial laser scanner (TLS). The consistency of the integrated techniques allowed to achieve a comprehensive and affordable characterization of the main joint sets on the sea cliff slope. The observed joint sets were considered to evaluate the proneness of the slope to rock failures by attributing safety factor (SF) values to the topple- and wedge-prone rock blocks under three combined or independent triggering conditions: (a) hydrostatic water pressures within the joints, (b) seismic action, and (c) strength reduction due to weathering of the joint surfaces. The combined action of weathering and water pressures within the joints was also considered, resulting in a significant decrease in the stability. Furthermore, remote survey analyses via InfraRed Thermography (IRT) and Ground Based Synthetic Aperture Radar Interferometry (GBInSAR) were performed to evaluate the role of the surveyed joint sets in inducing instabilities in the Mt. Pucci sea cliff. The results from the remote surveys: (i) GBInSAR monitoring revealed permanent displacements coupled to cyclic daily displacements, these last ones detected in certain sectors of the cliff wall; (ii) the thermal images allowed us to identify anomalies that correspond well to the main joints and to the slope material released due to recent collapses.
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Chen, Xue, Vladimiro Achilli, Massimo Fabris, Andrea Menin, Michele Monego, Giulia Tessari, and Mario Floris. "Combining Sentinel-1 Interferometry and Ground-Based Geomatics Techniques for Monitoring Buildings Affected by Mass Movements." Remote Sensing 13, no. 3 (January 28, 2021): 452. http://dx.doi.org/10.3390/rs13030452.
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Mass movements represent a serious threat to the stability of human structures and infrastructures, and cause loss of lives and severe damages to human properties every year worldwide. Built structures located on potentially unstable slopes are susceptible to deformations due to the displacement of the ground that at worst can lead to total destruction. Synthetic aperture radar (SAR) data acquired by Sentinel-1 satellites and processed by multi-temporal interferometric SAR (MT-InSAR) techniques can measure centimeter to millimeter-level displacement with weekly to monthly updates, characterizing long-term large-scale behavior of the buildings and slopes. However, the spatial resolution and short wavelength weaken the performance of Sentinel-1 in recognizing features (i.e., single buildings) inside image pixels and maintaining the coherence in mountainous vegetated areas. We have proposed and applied a methodology that combines Sentinel-1 interferometry with ground-based geomatics techniques, i.e., global navigation satellite system (GNSS), terrestrial laser scanning (TLS) and terrestrial structure from motion photogrammetry (SfM), for fully assessing building deformations on a slope located in the north-eastern Italian pre-Alps. GNSS allows verifying the ground deformation estimated by MT-InSAR and provides a reference system for the TLS and SfM measurements, while TLS and SfM allow the behavior of buildings located in the investigated slope to be monitored in great detail. The obtained results show that damaged buildings are located in the most unstable sectors of the slope, but there is no direct relationship between the rate of ground deformation of these sectors and the temporal evolution of damages to a single building, indicating that mass movements cause the displacement of blocks of buildings and each of them reacts differently according to its structural properties. This work shows the capability of MT-InSAR, GNSS, TLS and SfM in monitoring both buildings and geological processes that affect their stability, which plays a key role in geohazard analysis and assessment.
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Yamase, Keitaro, Toko Tanikawa, Masako Dannoura, Chikage Todo, Tomonori Yamamoto, Hidetoshi Ikeno, Mizue Ohashi, Kenji Aono, Ryuusei Doi, and Yasuhiro Hirano. "Estimating slope stability by lateral root reinforcement in thinned and unthinned stands of Cryptomeria japonica using ground-penetrating radar." CATENA 183 (December 2019): 104227. http://dx.doi.org/10.1016/j.catena.2019.104227.
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Kang, Ya, Zhong Lu, Chaoying Zhao, Qin Zhang, Jin-Woo Kim, and Yufen Niu. "Diagnosis of Xinmo (China) Landslide Based on Interferometric Synthetic Aperture Radar Observation and Modeling." Remote Sensing 11, no. 16 (August 8, 2019): 1846. http://dx.doi.org/10.3390/rs11161846.
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The Xinmo landslide occurred on 24 June 2017 and caused huge casualties and property losses. As characteristics of spatiotemporal pre-collapse deformation are a prerequisite for further understanding the collapse mechanism, in this study we applied the interferometric synthetic aperture radar (InSAR) technique to recover the pre-collapse deformation, which was further modeled to reveal the mechanism of the Xinmo landslide. Archived SAR data, including 44 Sentinel-1 A/B data and 20 Envisat/ASAR data, were used to acquire the pre-collapse deformation of the Xinmo landslide. Our results indicated that the deformation of the source area occurred as early as 10 years before the landslide collapsed. The deformation rate of source area accelerated about a month before the collapse, and the deformation rate in the week before the collapse reached 40 times the average before the acceleration. Furthermore, the pre-collapse deformation was modeled with a distributed set of rectangular dislocation sources. The characteristics of the pre-collapse movement of the slip surface were acquired, which further confirmed that a locked section formed at the bottom of the slope. In addition, the spatial-temporal characteristics of the deformation was found to have changed significantly with the development of the landslide. We suggested that this phenomenon indicated the expansion of the slip surface and cracks of the landslide. Due to the expansion of the slip surface, the locked section became a key area that held the stability of the slope. The locked section sheared at the last stage of the development, which triggered the final run-out. Our study has provided new insights into the mechanism of the Xinmo landslide.
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Infante, Donato, Diego Di Martire, Domenico Calcaterra, Pietro Miele, Anna Scotto di Santolo, and Massimo Ramondini. "Integrated Procedure for Monitoring and Assessment of Linear Infrastructures Safety (I-Pro MONALISA) Affected by Slope Instability." Applied Sciences 9, no. 24 (December 16, 2019): 5535. http://dx.doi.org/10.3390/app9245535.
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The occurrence of geological events such as landslides is one of the main causes of damage along linear infrastructures: Damage to transport infrastructures, as roads, bridges, and railways, can restrict their optimal functions and contribute to traffic accidents. The frequent and accurate monitoring of slope instability phenomena and of their interaction with existing man-made infrastructures plays a key role in risk prevention and mitigation activities. In this way, the use of high-resolution X-band synthetic aperture radar (SAR) data, characterized by short revisiting times, has demonstrated to be a powerful tool for a periodical noninvasive monitoring of ground motion and superstructure stability, aimed at improving the efficiency of inspection, repairing, and rehabilitation efforts. In the present work, we suggest a semiautomatic GIS approach, which, by using satellite radar interferometry data and results of geomorphological field survey integrated in a qualitative vulnerability matrix, allows to identify sections with different levels of damage susceptibility, where detailed conventional in situ measurements are required for further analysis. The procedure has been tested to investigate landslide-induced effects on a linear infrastructure in Campania Region (Italy), the Provincial Road “P.R. 264”, which is affected, along its linear development, by several slope instabilities. COSMO-SkyMed interferometric products, as indicator of ground kinematics, and results of in situ damage survey, as indicator of consequences, have been merged in a qualitative 4 × 4 matrix, thus obtaining a vulnerability zoning map along a linear infrastructure in January 2015. Furthermore, an updating of landslide inventory map is provided: In addition to 24 official landslides pre-mapped in 2012, 30 new events have been identified, and corresponding intensity and state of activity has been detected.
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Nichol, D., J. W. Lenham, and J. M. Reynolds. "Application of ground-penetrating radar to investigate the effects of badger setts on slope stability at St Asaph Bypass, North Wales." Quarterly Journal of Engineering Geology and Hydrogeology 36, no. 2 (May 2003): 143–53. http://dx.doi.org/10.1144/1470-9236/2002-42.
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mehrabi, ali. "Spatial Analysis and Monitoring of Slope Stability using Persistent Scatterer Tecnique of Sentinel 1 Radar Images, Case Study: Sarcheshmeh Copper Mine." Journal of Spatial Analysis Environmental Hazarts 7, no. 3 (November 1, 2020): 17–28. http://dx.doi.org/10.29252/jsaeh.7.3.17.
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Adamov, Yu, K. Boriak, and V. Zavalniuk. "ON IMPROVEMENT OF PARACHUTE-RETROROCKET AIRDROP SYSTEM." Collection of scientific works of the Military Institute of Kyiv National Taras Shevchenko University, no. 64 (2019): 5–13. http://dx.doi.org/10.17721/2519-481x/2019/64-01.
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The paper is devoted to the study of the prospects for improving the parachute-retrorocket airdrop system (PRS) in order to increase its reliability and enable the ability to adjust the orientation of a load in the horizontal plane depending on the slope of the earth's surface at the landing site. The primary task is to improve the accuracy of the altimeter, which determines the triggering moment of the PRS jet engines. The replacement of a mechanical altimeter of an outdated design with a modern electronic radio altimeter based on phased array radar is proposed, which allows to improve the accuracy of determining the absolute altitude(distance to the ground) and to take into account a roll of the load during the descent. The ways of determining the slope of earth's surface at the estimated landing site are also discussed. The results obtained make it possible to increase the accuracy of radio altimeter operation and significantly reduce the probability of an error in determining the absolute altitude due to rocking or static roll of the object. In addition to determining the current values of the height and speed of the descent of the vehicle, the use of a scanning radar makes it possible to estimate the inclination angle of the Earth’s surface at the landing site (in the radar scanning plane). If a certain angle of inclination of the earth surface at the landing site turns out to be too large, the probability of a successful landing can be increased by correcting the object's descent path, taking into account the information received. One of the easiest ways to correct a descent trajectory is to equip an object with small aerodynamic elements (rudders) and electromechanical actuators, ensuring their necessary orientation based on the results of determining the surface relief with radar. As one of the options, the authors propose the use of additional jet engines, which are structurally located on opposite sides of the object of landing in such a way as to form a torque of rotation of the object in a space from 0 ° to 90 ° in the horizontal plane due to the kinetic energy of motion from the actuation of jet engines. The triggering moment of the squibs is calculated based on determining the optimal distance of the object to the ground surface, and the need for triggering the squibs to rotate the object (correcting its position in space) depends on a certain value of the slope angle of the earth surface and comparing it with the admissible critical values of the angle, at which the object loses its stability during landing.
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Roberts, Nicholas J., Bernhard T. Rabus, John J. Clague, Reginald L. Hermanns, Marco-Antonio Guzmán, and Estela Minaya. "Changes in ground deformation prior to and following a large urban landslide in La Paz, Bolivia, revealed by advanced InSAR." Natural Hazards and Earth System Sciences 19, no. 3 (March 29, 2019): 679–96. http://dx.doi.org/10.5194/nhess-19-679-2019.
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Abstract. We characterize and compare creep preceding and following the complex 2011 Pampahasi landslide (∼40 Mm3±50 %) in the city of La Paz, Bolivia, using spaceborne radar interferometry (InSAR) that combines displacement records from both distributed and point scatterers. The failure remobilized deposits of an ancient complex landslide in weakly cemented, predominantly fine-grained sediments and affected ∼1.5 km2 of suburban development. During the 30 months preceding failure, about half of the toe area was creeping at 3–8 cm a−1 and localized parts of the scarp area showed displacements of up to 14 cm a−1. Changes in deformation in the 10 months following the landslide demonstrate an increase in slope activity and indicate that stress redistribution resulting from the discrete failure decreased stability of parts of the slope. During that period, most of the landslide toe and areas near the head scarp accelerated, respectively, to 4–14 and 14 cm a−1. The extent of deformation increased to cover most, or probably all, of the 2011 landslide as well as adjacent parts of the slope and plateau above. The InSAR-measured displacement patterns, supplemented by field observations and optical satellite images, reveal complex slope activity; kinematically complex, steady-state creep along pre-existing sliding surfaces accelerated in response to heavy rainfall, after which slightly faster and expanded steady creeping was re-established. This case study demonstrates that high-quality ground-surface motion fields derived using spaceborne InSAR can help to characterize creep mechanisms, quantify spatial and temporal patterns of slope activity, and identify isolated small-scale instabilities; such details are especially useful where knowledge of landslide extent and activity is limited. Characterizing slope activity before, during, and after the 2011 Pampahasi landslide is particularly important for understanding landslide hazard in La Paz, half of which is underlain by similar large paleolandslides.
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Crosta, G. B., and P. Frattini. "Distributed modelling of shallow landslides triggered by intense rainfall." Natural Hazards and Earth System Sciences 3, no. 1/2 (April 30, 2003): 81–93. http://dx.doi.org/10.5194/nhess-3-81-2003.
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Abstract. Hazard assessment of shallow landslides represents an important aspect of land management in mountainous areas. Among all the methods proposed in the literature, physically based methods are the only ones that explicitly includes the dynamic factors that control landslide triggering (rainfall pattern, land-use). For this reason, they allow forecasting both the temporal and the spatial distribution of shallow landslides. Physically based methods for shallow landslides are based on the coupling of the infinite slope stability analysis with hydrological models. Three different grid-based distributed hydrological models are presented in this paper: a steady state model, a transient "piston-flow" wetting front model, and a transient diffusive model. A comparative test of these models was performed to simulate landslide occurred during a rainfall event (27–28 June 1997) that triggered hundreds of shallow landslides within Lecco province (central Southern Alps, Italy). In order to test the potential for a completely distributed model for rainfall-triggered landslides, radar detected rainfall intensity has been used. A new procedure for quantitative evaluation of distributed model performance is presented and used in this paper. The diffusive model results in the best model for the simulation of shallow landslide triggering after a rainfall event like the one that we have analysed. Finally, radar data available for the June 1997 event permitted greatly improving the simulation. In particular, radar data allowed to explain the non-uniform distribution of landslides within the study area.
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Reyes-Carmona, Cristina, Anna Barra, Jorge Galve, Oriol Monserrat, José Pérez-Peña, Rosa Mateos, Davide Notti, et al. "Sentinel-1 DInSAR for Monitoring Active Landslides in Critical Infrastructures: The Case of the Rules Reservoir (Southern Spain)." Remote Sensing 12, no. 5 (March 3, 2020): 809. http://dx.doi.org/10.3390/rs12050809.
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Landslides in reservoir contexts are a well-recognised hazard that may lead to dangerous situations regarding infrastructures and people’s safety. Satellite-based radar interferometry is proving to be a reliable method to monitor the activity of landslides in such contexts. Here, we present a DInSAR (Differential Interferometric Synthetic Aperture Radar) analysis of Sentinel-1 images that exemplifies the usefulness of the technique to recognize and monitor landslides in the Rules Reservoir (Southern Spain). The integration of DInSAR results with a comprehensive geomorphological study allowed us to understand the typology, evolution and triggering factors of three active landslides: Lorenzo-1, Rules Viaduct and El Arrecife. We could distinguish between rotational and translational landslides and, thus, we evaluated the potential hazards related to these typologies, i.e., retrogression (Lorenzo-1 and Rules Viaduct landslides) or catastrophic slope failure (El Arrecife Landslide), respectively. We also observed how changes in the water level of the reservoir influence the landslide’s behaviour. Additionally, we were able to monitor the stability of the Rules Dam as well as detect the deformation of a highway viaduct that crosses a branch of the reservoir. Overall, we consider that other techniques must be applied to continue monitoring the movements, especially in the El Arrecife Landslide, in order to avoid future structural damages and fatalities.
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Yuter, Sandra E., David A. Stark, Justin A. Crouch, M. Jordan Payne, and Brian A. Colle. "The Impact of Varying Environmental Conditions on the Spatial and Temporal Patterns of Orographic Precipitation over the Pacific Northwest near Portland, Oregon." Journal of Hydrometeorology 12, no. 3 (June 1, 2011): 329–51. http://dx.doi.org/10.1175/2010jhm1239.1.
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Abstract Operational radar data from three winter seasons (2003–06) in Portland, Oregon, in the U.S. Pacific Northwest are used to describe how orographic precipitation varies with cross-barrier wind speed, 0°C level height, and stability over the moderately wide (~50-km half-width) Cascade Mountain Range. Orographic enhancement is specified in terms of location, frequency, and relative intensity of the reflectivity (precipitation field). The typical storm for the region, as defined by the 25th to 75th percentile characteristics, is compared to storms with <25th and >75th percentile characteristics for a given variable. About half of Portland-region storms have a low-level wind direction within a relatively narrow azimuth range. This subset of storms is used to examine the sensitivity of orographic enhancement relative to other environmental variables. Cross-barrier wind speed has a stronger role in determining the magnitude of precipitation frequency than either 0°C level or stability. Cross-barrier wind speed and 0°C level height have separate but comparable roles in determining the frequency of relatively heavier precipitation. The increase in precipitation frequency with stronger cross-barrier wind speed is partially attributed to the higher occurrence of intermittent convective cells intersecting the slope. The area where inferred riming growth occurs over local peaks on the windward slope broadens upslope as the 0°C level height increases. In the Portland region, variations in the squared moist Brunt–Väisälä frequency yield smaller differences in the pattern and intensity of precipitation enhancement than either cross-barrier wind speed or 0°C level height.
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Liu, Shuhao, Samuele Segoni, Federico Raspini, Kunlong Yin, Chao Zhou, Yiyue Zhang, and Nicola Casagli. "Satellite InSAR as a New Tool for the Verification of Landslide Engineering Remedial Works at the Regional Scale: A Case Study in the Three Gorges Resevoir Area, China." Applied Sciences 10, no. 18 (September 16, 2020): 6435. http://dx.doi.org/10.3390/app10186435.
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Several countries worldwide are funding large-scale programs to mitigate landslide risk by implementing engineering remedial works. However, the overall effectiveness of such measures is rarely monitored, and they are typically performed at the slope scale without fully exploiting the wide-area capabilities of remote sensing technologies. A multi-scale and multi-source monitoring procedure for evaluating the slope stability and the effectiveness of related remedial works was proposed in this study and applied in the middle section of the Three Gorges Reservoir Area (TGRA), China. The area is highly exposed to landslide hazards, and a massive program of engineering remedial works was recently implemented. Satellite interferometric synthetic aperture radar (InSAR)-based techniques were first exploited at the regional scale with the objective to provide a general overview of the deformative scenario and to highlight localized problems (active landslides or high deformation zones) to be further investigated; then, local-scale field investigation and multi-source ground monitoring data were employed to verify the deforming states of active landslides and to evaluate the effectiveness of the landslide engineering remedial works. The results indicated that, among the 310 mapped landslides in the study area, 52 were identified to be active and in a slow-moving state by satellite InSAR; Among the 58 controlled landslides, 9 of them were suspected to be active in a slow-moving state and require further concern. Particular attention was paid to two controlled landslides that were found in a continuously and progressively deforming state. We observed that the regional-scale program of slope stabilization was highly successful; however, the variation of the surrounding environmental setting could have led to landslide reactivation or partial invalidation of the landslide remedial works. The proposed multi-scale and multi-source monitoring framework is low-cost, easy to perform, and very straightforward to communicate to citizens and authorities. It can be easily implemented with very wide areas to assess the slope stability and to investigate the effectiveness of large-scale governmental risk mitigation programs, identifying precursor signals that could allow for intervention before reaching critical conditions.
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Nicholson, Lindsey I., Michael McCarthy, Hamish D. Pritchard, and Ian Willis. "Supraglacial debris thickness variability: impact on ablation and relation to terrain properties." Cryosphere 12, no. 12 (November 29, 2018): 3719–34. http://dx.doi.org/10.5194/tc-12-3719-2018.
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Abstract. Shallow ground-penetrating radar (GPR) surveys are used to characterize the small-scale spatial variability of supraglacial debris thickness on a Himalayan glacier. Debris thickness varies widely over short spatial scales. Comparison across sites and glaciers suggests that the skewness and kurtosis of the debris thickness frequency distribution decrease with increasing mean debris thickness, and we hypothesize that this is related to the degree of gravitational reworking the debris cover has undergone and is therefore a proxy for the maturity of surface debris covers. In the cases tested here, using a single mean debris thickness value instead of accounting for the observed small-scale debris thickness variability underestimates modelled midsummer sub-debris ablation rates by 11 %–30 %. While no simple relationship is found between measured debris thickness and morphometric terrain parameters, analysis of the GPR data in conjunction with high-resolution terrain models provides some insight into the processes of debris gravitational reworking. Periodic sliding failure of the debris, rather than progressive mass diffusion, appears to be the main process redistributing supraglacial debris. The incidence of sliding is controlled by slope, aspect, upstream catchment area and debris thickness via their impacts on predisposition to slope failure and meltwater availability at the debris–ice interface. Slope stability modelling suggests that the percentage of the debris-covered glacier surface area subject to debris instability can be considerable at glacier scale, indicating that up to 32 % of the debris-covered area is susceptible to developing ablation hotspots associated with patches of thinner debris.
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Shimada, Udai, Masahiro Sawada, and Hiroyuki Yamada. "Doppler Radar Analysis of the Rapid Intensification of Typhoon Goni (2015) after Eyewall Replacement." Journal of the Atmospheric Sciences 75, no. 1 (January 2018): 143–62. http://dx.doi.org/10.1175/jas-d-17-0042.1.
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A ground-based Doppler radar observed the rapid intensification (RI) of Typhoon Goni (2015) for 24 h immediately after it completed an eyewall replacement cycle. Goni’s RI processes were examined by using radar reflectivity and wind fields retrieved by the ground-based velocity track display (GBVTD) technique. The maximum wind at 2-km altitude increased by 30 m s−1 during the first 6 h of RI, and it further increased by 20 m s−1 during the subsequent 12 h. Around the onset of RI, relatively strong outflow (>2 m s−1) was present both inside and outside the radius of maximum wind (RMW) above the boundary layer (BL), suggesting the existence of supergradient flow in and just above the BL. Despite this outflow, angular momentum increased inside the RMW. The low-level RMW contracted rapidly from 50 to 33 km, causing the RMW to slope greatly outward with height. The radius of maximum reflectivity was a few kilometers inside the RMW. A budget analysis of absolute angular momentum showed that the outflow contributed to the contraction of the tangential wind field. During RI, eyewall convection was enhanced, and a well-defined eye appeared. The low-level outflow changed into inflow immediately outside the RMW. Then the tangential wind field and high inertial stability region expanded radially outward, followed by the formation of an outer reflectivity maximum at twice the RMW. The contraction speed of the low-level RMW slowed down.
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Gonga-Saholiariliva, N., Y. Gunnell, C. Petit, and C. Mering. "Techniques for quantifying the accuracy of gridded elevation models and for mapping uncertainty in digital terrain analysis." Progress in Physical Geography: Earth and Environment 35, no. 6 (July 13, 2011): 739–64. http://dx.doi.org/10.1177/0309133311409086.
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We first provide a critical review of statistical procedures employed in the literature for testing uncertainty in digital terrain analysis, then focus on several aspects of spatial autocorrelation that have been neglected in the analysis of gridded elevation data. When applied to first derivatives of elevation such as topographic slope, a spatial approach using Moran’s I and the LISA (Local Indicator of Spatial Association) allows: (1) georeferenced data patterns to be generated; (2) error hot- and coldspots to be located; and (3) error propagation during DEM manipulation to be evaluated. In a worked example focusing on the Wasatch mountain front, Utah, we analyse the relative advantages of six DEMs resulting from different acquisition modes (airborne, optical, radar, or composite): the LiDAR (2 m), CODEM (5 m), NED10 (10 m), ASTER DEM (15 m) and GDEM (30 m), and SRTM (90 m). The example shows that (apart from the LiDAR) the NED10, which is generated from composite data sources, is the least error-ridden DEM for that region. Knowing error magnitudes and where errors are located determines where corrections to elevation are required in order to minimize error accumulation or propagation, and clarifies how they might affect expert judgement in environmental decisions. Ground resolution issues can subsequently be addressed with greater confidence by resampling the preferred grid to terrain resolutions suited to the landscape attributes of interest. Source product testing is an essential yet often neglected part of DEM analysis, with many practical applications in hydrological modelling, for predictions of slope- to catchment-scale mass sediment flux, or for the assessment of slope stability thresholds.
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Rosaria, Maria Christine, Rania Salsabila, Muhammad Khalif Arda, Fery Andika Cahyo, and Rachmat Hamid Musa. "SLO VS INVERSE VELOCITY METHOD: A STUDY TO EXAMINE EFFECTIVE APPROACH TO PREDICT SLOPE FAILURE." Prosiding Temu Profesi Tahunan PERHAPI 1, no. 1 (March 29, 2020): 525–32. http://dx.doi.org/10.36986/ptptp.v1i1.94.
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ABSTRACT Provided with accurate and quasi real time deformation data, there are at least 2 methods that can be utilized to predict a slope failure. Inverse velocity method, coined by Fukuzono, aims at the interception of inverse velocity line to zero value at X time axis as the prediction of slope failure. More recent method called SLO, develop by Mufundirwa, puts emphasize on interception of acceleration regression line with X velocity axis. This paper is intended first and foremost to establish well-structured comparison between the two aforementioned methods. By using the same set of displacement data that show progressive deformation trend from Slope Stability radar, both SLO & Inverse Velocity method will be put into trial. Not only the accuracy of the failure prediction time, but also the comparison between the R2 attribute will be examine to reveal which method that yield better data statistically. One of the selected study case, from several which is presented on the paper, reveal that SLO method give failure prediction closer with the actual failure compared to Inverse Velocity method. The actual failure is happening at 21:59 AM January 1st 2016. SLO method generates failure prediction 10 minutes prior the actual failure, while Inverse Velocity generates failure prediction plus 68 minutes after the failure. R2 value for SLO method and Inverse Velocity method respectively are 0.710 & 0.630. Apart from this results comparison, a more in depth examination toward the nature of both methods delivers pro & con of each method. SLO method seems more accurate but having a constraint in which if there are no previous database of maximum velocity during collapse, prediction is almost impossible to make. Inverse Velocity method could address this flaw by projecting the inverse velocity line to zero value for the very least. Further explanation about the flaw and advantages of both methods will be conveyed in more detail on the later part of this paper. Key words: Failure Prediction, SLO, Inverse Velocity, SSR ABSTRAK Dengan adanya pengambilan data deformasi yang akurat dan mendekati “real time”, terdapat setidaknya dua metode yang dapat digunakan untuk memprediksi longsor. Metode inverse velocity, yang dikembangkan oleh Fukuzono, adalah metode yang menggunakan perpotongan grafik inverse velocity dengan titik nol sebagai acuan atau nilai dari prediksi longsor. Metode lain yang lebih baru dibandingkan metode inverse velocity adalah metode SLO yang dikembangkan oleh Mufundirwa. Metode ini lebih ditekankan pada perpotongan antara grafik akselerasi dengan nilai kecepatan pada sumbu X. Tujuan utama dari paper ini adalah penyajian perbandingan yang terstruktur antara kedua metode tersebut. Penelitian terhadap metode SLO dan inverse velocity menggunakan data deformasi progresif yang sama dari Slope Stability Radar. Tidak hanya keakuratan prediksi waktu longsor, tetapi perbandingan nilai R2 pun akan menentukan metode yang lebih efektif secara statistik. Pada salah satu studi kasus, dari beberapa kasus yang dibahas di paper ini, menunjukkan bahwa metode SLO memberikan prediksi waktu longsor yang lebih mendekati waktu longsor yang sebenarnya jika dibandingkan dengan metode inverse velocity. Longsor yang sebenarnya terjadi pada tanggal 1 Januari 2016, pukul 21:59. Metode SLO menghasilkan prediksi longsor 10 menit lebih awal dari waktu longsor yang sebenarnya, dimana metode inverse menghasilkan prediksi longsor 68 menit setelah waktu longsor. Nilai R2 untuk metode SLO dan inverse velocity adalah 0.71 dan 0.63. Di samping perbandingan kedua hasil di atas, pemahaman lebih mendalam tentang sumber dari kedua metode tersebut memunculkan hasil plus dan minus dari masing-masing metode. Metode SLO memang terlihat lebih akurat namun metode ini membutuhkan data kecepatan maksimal saat kejadian longsor sebelumnya. Jika tidak ada, maka prediksi hampir tidak mungkin untuk dibuat. Sebaliknya, kelemahan tersebut tidak terdapat pada metode inverse velocity karena dapat diproyeksikan pada titik nol. Penjelasan lebih dalam mengenai kelebihan dan kekurangan dari kedua metode tersebut akan dibahas selanjutnya pada paper ini. Kata kunci: Prediksi longsor, SLO, Inverse velocity, SSR
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Lu, Zhong, and Jinwoo Kim. "A Framework for Studying Hydrology-Driven Landslide Hazards in Northwestern US Using Satellite InSAR, Precipitation and Soil Moisture Observations: Early Results and Future Directions." GeoHazards 2, no. 2 (April 22, 2021): 17–40. http://dx.doi.org/10.3390/geohazards2020002.
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The mountainous Pacific Northwest is prone to heavy winter rainfall, resulting in hundreds of landslides per year, human casualties, and billions of dollars of property damage. Precipitation is a major hydrologic trigger for landslides in the northwestern US and around the world. This paper reviews existing literature to outline a framework to study the linkage between precipitation and landslide hazards over the northwestern US using satellite remote sensing techniques including interferometric synthetic aperture radar (InSAR) methods, Tropical Rainfall Measuring Mission (TRMM) satellite precipitation products, and Soil Moisture Active Passive (SMAP) satellite soil moisture data, along with correlation analysis and numerical modeling. InSAR time-series displacements provide an indication of landslide occurrence and extent, and help characterize the basal slip surface and slide-body volume based on the law of mass conservation. Precipitation and soil moisture sensed from the space and ground contribute to creating hydrogeological models associated with water infiltration. These crucial parameters are tracked through correlation and slope stability analysis to understand landslide dynamics. We highlight the results on mapping landslides over the state of Washington and analyses at a few select sites over southern Washington and southwestern Oregon. We conclude that satellite observations of landslide motions and the attributing hydrological variables from both radar and optical images improve our understanding of the inter-relationships between the hydrologic processes along with topographic and geologic settings, and the landslide kinematics and mechanisms inferred from time-series measurements and landslide modeling on a regional scale.
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Rehman, Mohib Ur, Yi Zhang, Xingmin Meng, Xiaojun Su, Filippo Catani, Gohar Rehman, Dongxia Yue, Zainab Khalid, Sajjad Ahmad, and Ijaz Ahmad. "Analysis of Landslide Movements Using Interferometric Synthetic Aperture Radar: A Case Study in Hunza-Nagar Valley, Pakistan." Remote Sensing 12, no. 12 (June 25, 2020): 2054. http://dx.doi.org/10.3390/rs12122054.
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From a geological standpoint, northern Pakistan is one of the most active and unstable areas in the world. As a consequence, many massive landslides have occurred in the area in historical times that have destroyed infrastructure, blocked the Hunza River, and damaged the Karakoram Highway repeatedly. However, despite the high frequency of large magnitude landslide events, and the consequent damages, the entire area is largely understudied, mainly due to the difficult logistics and the large distances involved. This work is aimed at applying the potential use of Interferometric Synthetic Aperture Radar (InSAR) for landslide identification and investigation for the Hunza-Nagar Region. Sentinel-1 images covering a period of more than two years (February 2017–August 2019) were used and processed by adopting the small baseline subset (SBAS) method. The obtained deformation rate measured along the line of sight (VLOS) varies from −114 to 20 mm/year. The downslope velocity deformation rates (Vslope) range from 0 to −300 mm/year. The Vslope stability threshold for our study area was calculated to be −14 mm/year from the Vslope standard deviation. Four active landslides with Vslope exceeding 14 mm/year were recognizable and have been confirmed by field inspection. The identified landslides listed from the most active to least active are the Humarri, Mayoon, Khai, and Ghulmet landslides, respectively. VLOS exceeding 114 mm/year was observed in the Humarri landslide, which posed a threat of damming a lake on the Hispar River and was also a risk to the Humarri Village located below the landslide. The maximum mean deformation detected in the Ghulmet, and Mayoon landslide was in the order of 30 mm/year and 20 mm/year, respectively. More importantly, it was found that in places, the slope deformation time series showed a patchy correlation with precipitation and seismic events in the area. This may indicate a complex, and possibly uncoupled, relationship between the two controlling agents promoting the deformation. However, the collective impact of the two factors is evident in the form of a continuously descending deformation curve and clearly indicates the ground distortion. The results indicate a potentially critical situation related to the high deformation rates measured at the Humarri landslide. On this specific slope, conditions leading to a possible catastrophic failure cannot be ruled out and should be a priority for the application of mitigation measures.
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Liu, L., K. Schaefer, A. Gusmeroli, G. Grosse, B. M. Jones, T. Zhang, A. D. Parsekian, and H. A. Zebker. "Seasonal thaw settlement at drained thermokarst lake basins, Arctic Alaska." Cryosphere 8, no. 3 (May 5, 2014): 815–26. http://dx.doi.org/10.5194/tc-8-815-2014.
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Abstract. Drained thermokarst lake basins (DTLBs) are ubiquitous landforms on Arctic tundra lowland. Their dynamic states are seldom investigated, despite their importance for landscape stability, hydrology, nutrient fluxes, and carbon cycling. Here we report results based on high-resolution Interferometric Synthetic Aperture Radar (InSAR) measurements using space-borne data for a study area located on the North Slope of Alaska near Prudhoe Bay, where we focus on the seasonal thaw settlement within DTLBs, averaged between 2006 and 2010. The majority (14) of the 18 DTLBs in the study area exhibited seasonal thaw settlement of 3–4 cm. However, four of the DTLBs examined exceeded 4 cm of thaw settlement, with one basin experiencing up to 12 cm. Combining the InSAR observations with the in situ active layer thickness measured using ground penetrating radar and mechanical probing, we calculated thaw strain, an index of thaw settlement strength along a transect across the basin that underwent large thaw settlement. We found thaw strains of 10–35% at the basin center, suggesting the seasonal melting of ground ice as a possible mechanism for the large settlement. These findings emphasize the dynamic nature of permafrost landforms, demonstrate the capability of the InSAR technique to remotely monitor surface deformation of individual DTLBs, and illustrate the combination of ground-based and remote sensing observations to estimate thaw strain. Our study highlights the need for better description of the spatial heterogeneity of landscape-scale processes for regional assessment of surface dynamics on Arctic coastal lowlands.
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Geerts, Bart, Qun Miao, and Yang Yang. "Boundary Layer Turbulence and Orographic Precipitation Growth in Cold Clouds: Evidence from Profiling Airborne Radar Data." Journal of the Atmospheric Sciences 68, no. 10 (October 1, 2011): 2344–65. http://dx.doi.org/10.1175/jas-d-10-05009.1.
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Abstract Airborne vertically pointing Doppler radar data collected in 10 winter storms over the Medicine Bow Range in Wyoming are used to examine the importance of boundary layer (BL) turbulence for orographic precipitation growth. In all 10 cases, the cloud-base temperature was below 0°C and the bulk Froude number was more than 1.0, implying little or no blocking of the flow by the mountain barrier. Seven of the 10 storms sampled were postfrontal, with weak static stability and relatively shallow cloud tops. Doppler vertical velocity transects depict an approximately 1-km-deep turbulent layer draped over the terrain, sometimes clearly distinct from the stratified flow in the free troposphere aloft, where vertical motion is largely controlled by gravity wave dynamics. Spectral analysis of near-surface Doppler vertical velocity data in terrain-following coordinates reveals an inertial subrange with decreasing power with height toward the BL top. The composite of radar data profiles from the 10 flights is analyzed in frequency-by-altitude diagrams, with altitude expressed above ground level. These diagrams indicate a wide range of vertical velocities in the BL, and rapid snow growth within the BL as air rises through the cloud base, especially when BL turbulence is more intense. This snow growth is concentrated on the windward side of mountains, above the terrain–cloud base intersection. The dominant snow growth mechanism in the BL (i.e., by accretion or vapor deposition) cannot be established because of restrictions in aircraft flight level over complex terrain. Snow aggregation may have contributed to the observed rapid increase in reflectivity in the BL along the windward slope.
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Huntley, David, Jessica Holmes, Peter Bobrowsky, Jonathan Chambers, Philip Meldrum, Paul Wilkinson, Shane Donohue, et al. "Hydrogeological and geophysical properties of the very-slow-moving Ripley Landslide, Thompson River valley, British Columbia." Canadian Journal of Earth Sciences 57, no. 12 (December 2020): 1371–91. http://dx.doi.org/10.1139/cjes-2019-0187.
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Landslides along a 10 km reach of Thompson River south of Ashcroft, British Columbia, have repeatedly damaged vital railway infrastructure, while also placing public safety, the environment, natural resources, and cultural heritage features at risk. Government agencies, universities, and the railway industry are focusing research efforts on a representative test site — the very-slow-moving Ripley Landslide — to manage better the geohazard risk in this corridor. We characterize the landslide’s form and function through hydrogeological and geophysical mapping. Field mapping and exploratory drilling distinguish 10 hydrogeological units in surficial deposits and fractured bedrock. Electrical resistivity tomography, frequency domain electromagnetic conductivity measurements, ground-penetrating radar, seismic pressure wave refraction, and multispectral analysis of shear waves; in conjunction with downhole measurement of natural gamma radiation, induction conductivity, and magnetic susceptibility provide a detailed, static picture of soil moisture and groundwater conditions within the hydrogeological units. Differences in electrical resistivity of the units reflect a combination of hydrogeological characteristics and climatic factors, namely temperature and precipitation. Resistive earth materials include dry glaciofluvial outwash and nonfractured bedrock; whereas glaciolacustrine clay and silt, water-bearing fractured bedrock, and periodically saturated subglacial till and outwash are conductive. Dynamic, continuous real-time monitoring of electrical resistivity, now underway, will help characterize water-flow paths, and possible relationships to independently monitor pore pressures and slope creep. These new hydrogeological and geophysical data sets enhance understanding of the composition and internal structure of this landslide and provide important context to interpret multiyear slope stability monitoring ongoing in the valley.
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Herzfeld, Ute C., and Bruce Wallin. "Spatio-temporal analysis of surface elevation changes in Pine Island Glacier, Antarctica, from ICESat GLAS data and ERS-1 radar altimeter data." Annals of Glaciology 55, no. 66 (2014): 248–58. http://dx.doi.org/10.3189/2014aog66a014.
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AbstractCharacterized by fast movement, low surface slope and grounding below sea level, Pine Island Glacier (PIG) plays an important role in the stability of the West Antarctic ice sheet. In previous work, we reported that the spatial distribution of 1995–2003 surface lowering in PIG suggests an attribution of changes to an internally forced process in the glacier. Other work associates changes in PIG entirely with processes in its ice shelf. Here time series of maps of surface elevation change in PIG and its ice shelf are derived from geostatistical analysis of ICESat GLAS and ERS-1 radar altimeter data. Based on spatio-temporal analysis of 1995–2007 elevation change, we discuss indications of processes that initiate from changes in the ice shelf versus processes that start internally in the glacier. Thinning rates continued to increase after 2003, regionally to >15 m a–1. The initiation of acceleration occurred in the interior of the ice stream, while in later years largest elevation loss was driven by changes in the ice shelf and upward propagation. By 2006, the region of thinning had expanded up-glacier beyond the initial areas of surface lowering to 100 km above the hinge line. More than one process causes dynamically complex changes in PIG.
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Delrieu, Guy, Anil Kumar Khanal, Nan Yu, Frédéric Cazenave, Brice Boudevillain, and Nicolas Gaussiat. "Preliminary investigation of the relationship between differential phase shift and path-integrated attenuation at the X band frequency in an Alpine environment." Atmospheric Measurement Techniques 13, no. 7 (July 10, 2020): 3731–49. http://dx.doi.org/10.5194/amt-13-3731-2020.
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Abstract. The RadAlp experiment aims at developing advanced methods for rainfall and snowfall estimation using weather radar remote sensing techniques in high mountain regions for improved water resource assessment and hydrological risk mitigation. A unique observation system has been deployed since 2016 in the Grenoble region of France. It is composed of an X-band radar operated by Météo-France on top of the Moucherotte mountain (1901 m above sea level; hereinafter MOUC radar). In the Grenoble valley (220 m above sea level; hereinafter a.s.l.), we operate a research X-band radar called XPORT and in situ sensors (weather station, rain gauge and disdrometer). In this paper we present a methodology for studying the relationship between the differential phase shift due to propagation in precipitation (Φdp) and path-integrated attenuation (PIA) at X band. This relationship is critical for quantitative precipitation estimation (QPE) based on polarimetry due to severe attenuation effects in rain at the considered frequency. Furthermore, this relationship is still poorly documented in the melting layer (ML) due to the complexity of the hydrometeors' distributions in terms of size, shape and density. The available observation system offers promising features to improve this understanding and to subsequently better process the radar observations in the ML. We use the mountain reference technique (MRT) for direct PIA estimations associated with the decrease in returns from mountain targets during precipitation events. The polarimetric PIA estimations are based on the regularization of the profiles of the total differential phase shift (Ψdp) from which the profiles of the specific differential phase shift on propagation (Kdp) are derived. This is followed by the application of relationships between the specific attenuation (k) and the specific differential phase shift. Such k–Kdp relationships are estimated for rain by using drop size distribution (DSD) measurements available at ground level. Two sets of precipitation events are considered in this preliminary study, namely (i) nine convective cases with high rain rates which allow us to study the ϕdp–PIA relationship in rain, and (ii) a stratiform case with moderate rain rates, for which the melting layer (ML) rose up from about 1000 up to 2500 m a.s.l., where we were able to perform a horizontal scanning of the ML with the MOUC radar and a detailed analysis of the ϕdp–PIA relationship in the various layers of the ML. A common methodology was developed for the two configurations with some specific parameterizations. The various sources of error affecting the two PIA estimators are discussed, namely the stability of the dry weather mountain reference targets, radome attenuation, noise of the total differential phase shift profiles, contamination due to the differential phase shift on backscatter and relevance of the k–Kdp relationship derived from DSD measurements, etc. In the end, the rain case study indicates that the relationship between MRT-derived PIAs and polarimetry-derived PIAs presents an overall coherence but quite a considerable dispersion (explained variance of 0.77). Interestingly, the nonlinear k–Kdp relationship derived from independent DSD measurements yields almost unbiased PIA estimates. For the stratiform case, clear signatures of the MRT-derived PIAs, the corresponding ϕdp value and their ratio are evidenced within the ML. In particular, the averaged PIA∕ϕdp ratio, a proxy for the slope of a linear k–Kdp relationship in the ML, peaks at the level of the copolar correlation coefficient (ρhv) peak, just below the reflectivity peak, with a value of about 0.42 dB per degree. Its value in rain below the ML is 0.33 dB per degree, which is in rather good agreement with the slope of the linear k–Kdp relationship derived from DSD measurements at ground level. The PIA∕ϕdp ratio remains quite high in the upper part of the ML, between 0.32 and 0.38 dB per degree, before tending towards 0 above the ML.
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D’Aranno, Peppe J. V., Alessandro Di Benedetto, Margherita Fiani, Maria Marsella, Ilaria Moriero, and José Antonio Palenzuela Baena. "An Application of Persistent Scatterer Interferometry (PSI) Technique for Infrastructure Monitoring." Remote Sensing 13, no. 6 (March 10, 2021): 1052. http://dx.doi.org/10.3390/rs13061052.
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In the absence of systematic structural monitoring to support adequate maintenance standards, many existing infrastructures may reach unacceptable quality levels during their life cycle, resulting in significant damage and even potential failure. The metropolitan area of the Gulf of Salerno (Italy), served by a complex multimodal transport network connecting the port area to the roads and railways surrounding the urban area, represents an important industrial and commercial hub at the local and international scale. This particular scenario, developed in a complex morphological and geological context, has led to the interference and overlapping of the transport network (highway, railway, main and secondary roads) that run through the piedmont area north of the port. Given the relevance of the area, our research aims to highlight the capabilities of the persistent scatterer interferometry (PSI) technique, belonging to the group of differential interferometric synthetic aperture radar (SAR), to extract space–temporal series of displacements on ground points or artifacts with millimeter accuracy useful to understand ongoing deformation processes. By using archived data from the European Space Agency missions, i.e., ERS1/2 (European remote-sensing satellite) and ENVISAT (environmental satellite), and the most recent data from COSMO-SkyMed constellations, it was possible to collect a 28-year dataset that was used to spatially analyze displacement patterns at a site-specific scale to check the stability of viaducts and embankments, and on a larger scale to understand the activity of the surrounding slopes. Despite the different resolution and subsequently the ground density, the analysis of the different datasets showed a spatiotemporal consistency in the displacement patterns that concerned two subareas showing significant annual velocity trends, one northeast of the city and the second in the port area. The analysis presented in this paper highlights how a complex geologic area, combining slope movements and various fault systems, could be a major concern for the stability of the overlying infrastructure and also the role that a PSI analysis can play in remotely monitoring their behavior over long periods of time.
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Vaccari, Andrea, Tamal Batabyal, Nazia Tabassum, Edward J. Hoppe, Brian S. Bruckno, and Scott T. Acton. "Integrating Remote Sensing Data in Decision Support Systems for Transportation Asset Management." Transportation Research Record: Journal of the Transportation Research Board 2672, no. 45 (July 15, 2018): 23–35. http://dx.doi.org/10.1177/0361198118786645.
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The objective of the research summarized in this manuscript is two-fold: to develop and make available a set of novel analysis tools, fully integrated in ArcGIS, that leverages the rich information provided by satellite-based remote sensing data to detect and characterize geohazards of interest to the transportation community; and to provide a modern web-based decision support system (DSS) in which these novel analysis products can be seamlessly integrated with existing datasets. Specifically, interferometric synthetic aperture radar (InSAR) and its derivatives are employed in this work. Each tool is designed to target a specific asset of interest to the transportation community: sinkhole detection, bridge differential settlement detection, slope stability assessment, and pavement distress evaluation. Furthermore, to allow interested parties to test the introduction of remote sensing data into their decision-making process without requiring the full integration with existing workflows, a modern web-based DSS is introduced. Thanks to the large coverage and the high update frequencies offered by satellite-based remote sensing data, datasets augmented with these new products can offer a near real-time overview of the network status and lead to better support in decisions about resources allocation, existing infrastructure monitoring, new infrastructure planning, and post-construction assessment.
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Gómez, Diego, Pablo Salvador, Julia Sanz, Carlos Casanova, and Jose Casanova. "Detecting Areas Vulnerable to Sand Encroachment Using Remote Sensing and GIS Techniques in Nouakchott, Mauritania." Remote Sensing 10, no. 10 (September 25, 2018): 1541. http://dx.doi.org/10.3390/rs10101541.
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Sand dune advances poses a major threat to inhabitants and local authorities in the area of Nouakchott, Mauritania. Despite efforts to control dune mobility, accurate and adequate local studies are still needed to tackle sand encroachment. We have developed a Sand Dune Encroachment Vulnerability Index (SDEVI) to assess Nouakchott’s vulnerability to sand dune encroachment. Said index is based on the geo-physical characteristics of the area (wind direction and intensity, slope and surface height, land use, vegetation or soil properties) with Geographic Information System (GIS) techniques that can support local authorities and decision-makers in implementing preventive measures or reducing impact on the population and urban infrastructures. In order to validate this new index, we use two remote sensing approaches: optical-Sentinel 2 and Synthetic Aperture Radar (SAR)–Sentinel 1 data. Results show that the greatest vulnerability is located in the north-eastern part of Nouakchott, where local conditions favor the advance of sand in the city, although medium to high values are also found in the eastern part. Optical images enabled us to distinguish desert sand using the ratio between near infrared/blue bands, and SAR Coherence Change Detection (CCD) imagery was used to assess the degree of stability of those sand bodies. The nature of the SDEVI index allows us to currently assess which areas are vulnerable to sand encroachment since we use long data records. Nevertheless, optical and SAR remote sensing allow sand evolution to be monitored on a near real-time basis.
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Jordan, Tom A., David Porter, Kirsty Tinto, Romain Millan, Atsuhiro Muto, Kelly Hogan, Robert D. Larter, Alastair G. C. Graham, and John D. Paden. "New gravity-derived bathymetry for the Thwaites, Crosson, and Dotson ice shelves revealing two ice shelf populations." Cryosphere 14, no. 9 (September 9, 2020): 2869–82. http://dx.doi.org/10.5194/tc-14-2869-2020.
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Abstract. Ice shelves play a critical role in the long-term stability of ice sheets through their buttressing effect. The underlying bathymetry and cavity thickness are key inputs for modelling future ice sheet evolution. However, direct observation of sub-ice-shelf bathymetry is time-consuming, logistically risky, and in some areas simply not possible. Here we use new compilations of airborne and marine gravity, radar depth sounding, and swath bathymetry to provide new estimates of sub-ice-shelf bathymetry outboard of the rapidly changing West Antarctic Thwaites Glacier and beneath the adjacent Dotson and Crosson ice shelves. This region is of special interest, as the low-lying inland reverse slope of the Thwaites Glacier system makes it vulnerable to marine ice sheet instability, with rapid grounding line retreat observed since 1993 suggesting this process may be underway. Our results confirm a major marine channel >800 m deep extends tens of kilometres to the front of Thwaites Glacier, while the adjacent ice shelves are underlain by more complex bathymetry. Comparison of our new bathymetry with ice shelf draft reveals that ice shelves formed since 1993 comprise a distinct population where the draft conforms closely to the underlying bathymetry, unlike the older ice shelves, which show a more uniform depth of the ice base. This indicates that despite rapid basal melting in some areas, these recently floated parts of the ice shelf are not yet in dynamic equilibrium with their retreated grounding line positions and the underlying ocean system, a factor which must be included in future models of this region's evolution.
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Huntley, David, Peter Bobrowsky, Michael Hendry, Renato Macciotta, and Melvyn Best. "Multi-technique Geophysical Investigation of a Very Slow-moving Landslide near Ashcroft, British Columbia, Canada." Journal of Environmental and Engineering Geophysics 24, no. 1 (March 2019): 87–110. http://dx.doi.org/10.2113/jeeg24.1.87.
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Landslides in the Thompson River valley, British Columbia have the potential to adversely impact vital national railway infrastructure and operations, the natural environment, cultural heritage features, communities, public safety and the economy. To better manage geohazard risks in the primary national transportation corridor, government agencies, universities and railway industry partners are focusing research efforts on the Ripley Landslide, 7 km south of Ashcroft. The internal composition and structure of this very slow-moving landslide as revealed by geophysical surveys and terrain mapping provides contextual baseline data for interpreting slope stability monitoring results and guiding geohazard mitigation efforts. Terrestrial and waterborne geophysical surveys were undertaken using subsets of the following methods: electrical resistivity tomography, frequency electromagnetic conductivity, ground penetrating radar, primary-wave refraction and multispectral analysis of shear-waves, natural gamma radiation, induction conductivity and magnetic susceptibility. Small and irregular anomalies, areas of complex subsurface geometry and groundwater-rich zones are resolved along all terrestrial geophysical survey lines. Terrain mapping and geophysical surveys indicate a high relief bedrock sub-surface overlain by a 10 m to >30 m thick package of complex fine-grained sediments containing groundwater. Planar sub-surface features revealed in surface exposures, borehole logs and geophysical profiles include tabular bedding and terrain unit contacts. Profiles also show discrete curvilinear features interpreted as rotational-translational failure planes in clay-rich beds in the main body of the slide beneath the rail ballast and retaining wall. Integrating data from surficial geology mapping and an array of geophysical methods provided significantly more information than any one technique on its own.