Sample records for sar insar analysis

  1. GIAnT - Generic InSAR Analysis Toolbox (United States)

    Agram, P.; Jolivet, R.; Riel, B. V.; Simons, M.; Doin, M.; Lasserre, C.; Hetland, E. A.


    We present a computing framework for studying the spatio-temporal evolution of ground deformation from interferometric synthetic aperture radar (InSAR) data. Several open-source tools including Repeat Orbit Interferometry PACkage (ROI-PAC) and InSAR Scientific Computing Environment (ISCE) from NASA-JPL, and Delft Object-oriented Repeat Interferometric Software (DORIS), have enabled scientists to generate individual interferograms from raw radar data with relative ease. Numerous computational techniques and algorithms that reduce phase information from multiple interferograms to a deformation time-series have been developed and verified over the past decade. However, the sharing and direct comparison of products from multiple processing approaches has been hindered by - 1) absence of simple standards for sharing of estimated time-series products, 2) use of proprietary software tools with license restrictions and 3) the closed source nature of the exact implementation of many of these algorithms. We have developed this computing framework to address all of the above issues. We attempt to take the first steps towards creating a community software repository for InSAR time-series analysis. To date, we have implemented the short baseline subset algorithm (SBAS), NSBAS and multi-scale interferometric time-series (MInTS) in this framework and the associated source code is included in the GIAnT distribution. A number of the associated routines have been optimized for performance and scalability with large data sets. Some of the new features in our processing framework are - 1) the use of daily solutions from continuous GPS stations to correct for orbit errors, 2) the use of meteorological data sets to estimate the tropospheric delay screen and 3) a data-driven bootstrapping approach to estimate the uncertainties associated with estimated time-series products. We are currently working on incorporating tidal load corrections for individual interferograms and propagation of

  2. Accelerated Scientific InSAR Processing Project (United States)

    National Aeronautics and Space Administration — Neva Ridge Technologies proposes to develop a suite of software tools for the analysis of SAR and InSAR data, focused on having a robust and adopted capability well...

  3. Long-range ground deformation monitoring by InSAR analysis

    Directory of Open Access Journals (Sweden)

    S. Rokugawa


    Full Text Available InSAR (Interferometric Synthetic Aperture Radar analysis is an effective technique to map 3-dimensional surface deformation with high spatial resolution. The aim of this study was to evaluate the capability of InSAR analysis when applied to ground monitoring of an environmental disaster. We performed a time series InSAR analysis using ENVISAT/ASAR and ALOS/PALSAR data and commercial software to investigate subsidence around the Kanto District of Japan. We also investigated techniques for efficient early detection of landslides in Kyushu using time series analysis that incorporated synthetic aperture radar (SAR images. ENVISAT/ASAR data acquired from 2003–2010 and ALOS/PALSAR data acquired from 2006–2011 were used to detect poorly expressed geomorphological deformation by conducting time series analyses of periodically acquired SAR data. In addition, to remove noise caused by geographical feature stripes or phase retardation, we applied median filtering, histogram extraction processing, and clarification of the displacement with a Laplacian filter. The main functions of the InSAR time series analysis are the calculation of phase differences between two images and the inversion with smoothness constraint for the estimation of deformation along the line of sight. The results enabled us to establish criteria for the selection of suitable InSAR data pairs, and provided the final error estimation of the derived surface deformation. The results of the analysis in the Kanto District suggested that localized areas of uplift and subsidence have occurred at irregular intervals in this area. Furthermore, the method offers the possibility of early warning of environmental disasters such as landslide and abrupt subsidence. Our results confirm the effectiveness of InSAR analysis for the monitoring of ground deformation over wide areas via the detection of localized subsidence and landslides.

  4. Wetland InSAR (United States)

    Wdowinski, S.; Kim, S.; Amelung, F.; Dixon, T.


    Wetlands are transition zones where the flow of water, the nutrient cycling, and the sun energy meet to produce a unique and very productive ecosystem. They provide critical habitat for a wide variety of plant and animal species, including the larval stages of many ocean fish. Wetlands also have a valuable economical importance, as they filter nutrients and pollutants from fresh water used by human and provide aquatic habitats for outdoor recreation, tourism, and fishing. Globally, many such regions are under severe environmental stress, mainly from urban development, pollution, and rising sea level. However, there is increasing recognition of the importance of these habitats, and mitigation and restoration activities have begun in a few regions. A key element in wetlands conservation, management, and restoration involves monitoring its hydrologic system, as the entire ecosystem depends on its water supply. Heretofore, hydrologic monitoring of wetlands are conducted by stage (water level) stations, which provide good temporal resolution, but suffer from poor spatial resolution, as stage station are typically distributed several, or even tens of kilometers, from one another. Wetland application of InSAR provides the needed high spatial resolution hydrological observations, complementing the high temporal resolution terrestrial observations. Although conventional wisdom suggests that interferometry does not work in vegetated areas, several studies have shown that both L- and C-band interferograms with short acquisition intervals (1-105 days) can maintain excellent coherence over wetlands. In this study we explore the usage of InSAR for detecting water level changes in various wetland environments around the world, including the Everglades (south Florida), Louisiana Coast (southern US), Chesapeake Bay (eastern US), Pantanal (Brazil), Okavango Delta (Botswana), and Lena Delta (Siberia). Our main study area is the Everglades wetland (south Florida), which is covered by

  5. Pre-2014 mudslides at Oso revealed by InSAR and multi-source DEM analysis (United States)

    Kim, J. W.; Lu, Z.; QU, F.


    The landslide is a process that results in the downward and outward movement of slope-reshaping materials including rocks and soils and annually causes the loss of approximately $3.5 billion and tens of casualties in the United States. The 2014 Oso mudslide was an extreme event costing nearly 40 deaths and damaging civilian properties. Landslides are often unpredictable, but in many cases, catastrophic events are repetitive. Historic record in the Oso mudslide site indicates that there have been serial events in decades, though the extent of sliding events varied from time to time. In our study, the combination of multi-source DEMs, InSAR, and time-series InSAR analysis has enabled to characterize the Oso mudslide. InSAR results from ALOS PALSAR show that there was no significant deformation between mid-2006 and 2011. The combination of time-series InSAR analysis and old-dated DEM indicated revealed topographic changes associated the 2006 sliding event, which is confirmed by the difference of multiple LiDAR DEMs. Precipitation and discharge measurements before the 2006 and 2014 landslide events did not exhibit extremely anomalous records, suggesting the precipitation is not the controlling factor in determining the sliding events at Oso. The lack of surface deformation during 2006-2011 and weak correlation between the precipitation and the sliding event, suggest other factors (such as porosity) might play a critical role on the run-away events at this Oso and other similar landslides.

  6. Bryan Mound InSAR Analysis U.S. Strategic petroleum Reserve.

    Energy Technology Data Exchange (ETDEWEB)

    Lord, Anna C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)


    The U.S. Strategic Petroleum Reserve (SPR) is a stockpile of emergency crude oil to be tapped into if a disruption in the nation's oil supply occurs. The SPR is comprised of four salt dome sites. Subsidence surveys have been conducted either annually or biennially at all four sites over the life of the program. Monitoring of surface behavior is a first line defense to detecting possible subsurface cavern integrity issues. Over the life of the Bryan Mound site, subsidence rates over abandoned Cavern 3 have continuously been the highest at the site. In an effort to try and understand the subsurface dynamics, specifically over Bryan Mound Cavern 3, historic interferometric synthetic aperture radar (InSAR) data was acquired and processed by TRE Altamira. InSAR involves the processing of multiple satellite synthetic aperture radar scenes acquired across the same location of the Earth's surface at different times to map surface deformation. The analysis of the data has the ability to detect millimeters of motion spanning days, months, year and decades, across specific sites. The intent in regards to the Bryan Mound site was (1) to confirm the higher subsidence rates recorded over abandoned Cavern 3 indicated by land survey and (2) understand the regional surface behavior. This report describes the InSAR analysis results, how those results compare to the historical collection of land survey data, and what additional information the data has provided towards understanding the response recorded at the surface.

  7. New Ground Truth Capability from InSAR Time Series Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Buckley, S; Vincent, P; Yang, D


    We demonstrate that next-generation interferometric synthetic aperture radar (InSAR) processing techniques applied to existing data provide rich InSAR ground truth content for exploitation in seismic source identification. InSAR time series analyses utilize tens of interferograms and can be implemented in different ways. In one such approach, conventional InSAR displacement maps are inverted in a final post-processing step. Alternatively, computationally intensive data reduction can be performed with specialized InSAR processing algorithms. The typical final result of these approaches is a synthesized set of cumulative displacement maps. Examples from our recent work demonstrate that these InSAR processing techniques can provide appealing new ground truth capabilities. We construct movies showing the areal and temporal evolution of deformation associated with previous nuclear tests. In other analyses, we extract time histories of centimeter-scale surface displacement associated with tunneling. The potential exists to identify millimeter per year surface movements when sufficient data exists for InSAR techniques to isolate and remove phase signatures associated with digital elevation model errors and the atmosphere.

  8. Highway Subsidence Analysis Based on the Advanced InSAR Time Series Analysis Method (United States)

    Zhang, Qingyun; Zhang, Jingfa; Liu, Guolin; Li, Yongsheng


    The synthetic aperture radar (InSAR) measurements have the advantages of all-weather, wide range, high precision on the surface deformation monitoring. Highway as an important index of modern social and economic development, the quality and deformation changes in the process of using have a significant impact in the social development and people's life and property security. In practical applications the InSAR technology should do a variety of error correction analysis. By using a new analysis method – FRAM- SBAS time-series analysis method, to analyze the settlement of highway on Yanzhou area by the ALOS PALSAR datas. Use FRAM- SBAS timing analysis method to obtain the surface timing changes during 2008-09-21 to 2010-07-18 in the Jining area and obtained good results, the Jining area maximum timing settlement is 60mm, the maximum settlement rate reached 30mm/yr. The maximum settlement of the highway section is 53mm, the maximum settlement rate is 32mm/yr. And the settlement of highway worst sections were in severe ground subsidence, thus proving the mining and vehicle load effect on settlement of highway. And it is proved that the timing method on the ground and highway subsidence monitoring is feasible.

  9. Permanent Scatterer InSAR Analysis and Validation in the Gulf of Corinth

    Directory of Open Access Journals (Sweden)

    Charalabos Kontoes


    Full Text Available The Permanent Scatterers Interferometric SAR technique (PSInSAR is a method that accurately estimates the near vertical terrain deformation rates, of the order of ~1 mm year-1, overcoming the physical and technical restrictions of classic InSAR. In this paper the method is strengthened by creating a robust processing chain, incorporating PSInSAR analysis together with algorithmic adaptations for Permanent Scatterer Candidates (PSCs and Permanent Scatterers (PSs selection. The processing chain, called PerSePHONE, was applied and validated in the geophysically active area of the Gulf of Corinth. The analysis indicated a clear subsidence trend in the north-eastern part of the gulf, with the maximum deformation of ~2.5 mm year-1 occurring in the region north of the Gulf of Alkyonides. The validity of the results was assessed against geophysical/geological and geodetic studies conducted in the area, which include continuous seismic profiling data and GPS height measurements. All these observations converge to the same deformation pattern as the one derived by the PSInSAR technique.

  10. Analysis of the Effect of Radio Frequency Interference on Repeat Track Airborne InSAR System

    Directory of Open Access Journals (Sweden)

    Ding Bin


    Full Text Available The SAR system operating at low frequency is susceptible to Radio Frequency Interference (RFI from television station, radio station, and some other civil electronic facilities. The presence of RFI degrades the SAR image quality, and obscures the targets in the scene. Furthermore, RFI can cause interferometric phase error in repeat track InSAR system. In order to analyze the effect of RFI on interferometric phase of InSAR, real measured RFI signal are added on cone simulated SAR echoes. The imaging and interferometric processing results of both the RFI-contaminated and raw data are given. The effect of real measured RFI signal on repeat track InSAR system is analyzed. Finally, the imaging and interferometric processing results of both with and without RFI suppressed of the P band airborne repeat track InSAR real data are presented, which demonstrates the efficiency of the RFI suppression method in terms of decreasing the interferometric phase errors caused by RFI.

  11. Ka-band InSAR Imaging and Analysis Based on IMU Data

    Directory of Open Access Journals (Sweden)

    Shi Jun


    Full Text Available Compared with other bands, the millimeter wave Interferometric Synthetic Aperture Radar (InSAR has high accuracy and small size, which is a hot topic in InSAR research. On the other hand, shorter wavelength causes difficulties in 2D imaging and interferometric phase extraction. In this study, the imaging and phase performance of the streaming Back Projection (BP method combined with IMU data are analyzed and discussed on the basis of actual Ka-band InSAR data. It is found that because the wavelength of the Ka-band is short, it is more sensitive to the antenna phase-center history. To ensure the phase-preserving capacity, the IMU data must be used with accurate motion error compensation. Furthermore, during data processing, we verify the flat-earth-removing capacity of the BP algorithm that calculates and compensates the master and slave antenna phase centers individually.

  12. L- and X-Band Multi-Temporal InSAR Analysis of Tianjin Subsidence

    Directory of Open Access Journals (Sweden)

    Qingli Luo


    Full Text Available When synthetic aperture radar interferometry (InSAR technology is applied in the monitoring of land subsidence, the sensor band plays an important role. An X-band SAR system as TerraSAR-X (TSX provides high resolution and short revisit time, but it has no capability of global coverage. On the other side, an L-band sensor as Advanced Land Observing Satellite-Phased Array L-band Synthetic Aperture Radar (ALOS-PALSAR has global coverage and it produces highly coherent interferograms, but it provides much less details in time and space. The characteristics of these two satellites from different bands can be regarded as complementary. In this paper, we firstly present a possible strategy for X-band optimized acquisition planning combining with L-band. More importantly, we also present the multi-temporal InSAR (MT-InSAR analysis results from 23 ALOS-PALSAR images and 37 TSX data, which show the complementarity of L- and X-band allows measuring deformations both in urban and non-urban areas. Furthermore, the validation between MT-INSAR and leveling/GPS has been carried out. The combination analysis of L- and X-band MT-InSAR results effectively avoids the limitation of X-band, providing a way to define the shape and the borderline of subsiding center and helps us to understand the subsidence mechanism. Finally, the geological interpretation of the detected subsidence center is given.

  13. Antiparallel Aspects of Airborne Dual-antenna InSAR Data Processing and Analysis

    Directory of Open Access Journals (Sweden)

    Li Fang-fang


    Full Text Available Interferometric Synthetic Aperture Radar (InSAR is a powerful technique for precise topographic mapping. However, owing to the side-looking SAR imaging geometry, geometry distortions appear in mountainous scenarios. Because of phase discontinuities or the absence of a valid phase, it is difficult to recover accurate DEM in such areas with single-aspect InSAR data. Fusion of two or more different aspects of InSAR data can deal with this problem in practice. Experiments using two antiparallel aspects of airborne InSAR data are carried out based on this idea. To decrease the processing error in single-aspect data and fuse them seamlessly, a MOtion COmpensation (MOCO method using iterative DEM is used to reduce the MOCO error. Besides, phase-unwrapping methods based on terrain characteristics are proposed to avoid phase-unwrapping error owing to phase discontinuities in areas of shadow and layover. Experimental results verify the effectiveness of the processing methods.

  14. DEM generated from InSAR in mountainous terrain and its accuracy analysis (United States)

    Hu, Hongbing; Zhan, Yulan


    Digital Elevation Model (DEM) derived from survey data is accurate but it is very expensive and time-consuming. In recent years, remote sensing techniques including Synthetic Apenture Radar Interferometry (InSAR) had been developed as a powerful method to derive high precision DEM, especially in mountainous or deep forest areas. The purpose of this paper is to illustrate the principle of InSAR and show the result of a case study in Gejiu city, Yunnan province, China. The accuracy of DEM derived from InSAR (abbreviation as InSAR-DEM) is also evaluated by comparing it with DEM generated from topographic map at the scale of 1:50000 (abbreviation as TOP-DEM). The result shows that: (1)The general precision of the whole selected area acquired by subtracting InSAR-DEM from TOP-DEM is that the maximum, the minimum, the RMSE, and the mean of difference of the two DEMs are 203m, -188m, 26.9m and 5.7m respectively. (2)The topographic trend represented by the two DEMs is coincident, even though TOP-DEM is finer than InSAR-DEM, especial at the valley. (3) Contour maps with the interval of 100m and 50m converted from InSAR-DEM and TOP-DEM respectively show accordant relief trend. Contour from TOP-DEM is smoother than that of from InSAR-DEM, while Contour from InSAR-DEM has more islands than that of from TOP-DEM.(4) Coherence has great influence on the precision of InSAR-DEM, the precision of low-coherence area approaches 100 m while that of high-coherence area can up to m level. (5) The relief trend of 6 profiles represented by InSAR-DEM and TOP-DEM is accordant with tiny difference in partial minutiae. InSAR-DEM displays hypsographies at relative flat areas including surface of water, which reflects the influence of flat earth on InSAR to a certain extent.

  15. Applications and development of new algorithms for displacement analysis using InSAR time series (United States)

    Osmanoglu, Batuhan

    Time series analysis of Synthetic Aperture Radar Interferometry (InSAR) data has become an important scientific tool for monitoring and measuring the displacement of Earth's surface due to a wide range of phenomena, including earthquakes, volcanoes, landslides, changes in ground water levels, and wetlands. Time series analysis is a product of interferometric phase measurements, which become ambiguous when the observed motion is larger than half of the radar wavelength. Thus, phase observations must first be unwrapped in order to obtain physically meaningful results. Persistent Scatterer Interferometry (PSI), Stanford Method for Persistent Scatterers (StaMPS), Short Baselines Interferometry (SBAS) and Small Temporal Baseline Subset (STBAS) algorithms solve for this ambiguity using a series of spatio-temporal unwrapping algorithms and filters. In this dissertation, I improve upon current phase unwrapping algorithms, and apply the PSI method to study subsidence in Mexico City. PSI was used to obtain unwrapped deformation rates in Mexico City (Chapter 3),where ground water withdrawal in excess of natural recharge causes subsurface, clay-rich sediments to compact. This study is based on 23 satellite SAR scenes acquired between January 2004 and July 2006. Time series analysis of the data reveals a maximum line-of-sight subsidence rate of 300mm/yr at a high enough resolution that individual subsidence rates for large buildings can be determined. Differential motion and related structural damage along an elevated metro rail was evident from the results. Comparison of PSI subsidence rates with data from permanent GPS stations indicate root mean square (RMS) agreement of 6.9 mm/yr, about the level expected based on joint data uncertainty. The Mexico City results suggest negligible recharge, implying continuing degradation and loss of the aquifer in the third largest metropolitan area in the world. Chapters 4 and 5 illustrate the link between time series analysis and three

  16. Aseismic deformation across the Hilina fault system, Hawaii, revealed by wavelet analysis of InSAR and GPS time series (United States)

    Shirzaei, M.; Bürgmann, R.; Foster, J.; Walter, T. R.; Brooks, B. A.


    The Hilina Fault System (HFS) is located on the south flank of Kilauea volcano and is thought to represent the surface expression of an unstable edifice sector that is active during seismic events such as the 1975 Kalapana earthquake. Despite its potential for hazardous landsliding and associated tsunamis, no fault activity has yet been detected by means of modern geodetic methods, since the 1975 earthquake. We present evidence from individual SAR interferograms, as well as cluster analysis and wavelet analysis of GPS and InSAR time series, which suggest an inferred differential motion at HFS. To investigate the effect of atmospheric delay on the observed differential motion, we implement a statistical approach using wavelet transforms. We jointly analyze InSAR and continuous GPS deformation data from 2003 to 2010, to estimate the likelihood that the subtle time-dependent deformation signal about the HFS scarps is not associated with the atmospheric delay. This integrated analysis reveals localized deformation components in the InSAR deformation time series that are superimposed on the coherent motion of Kilauea's south flank. The statistical test suggests that at 95% confidence level, the identified differential deformation at HFS is not due to atmospheric artifacts. Since no significant shallow seismicity is observed over the study period, we suggest that this deformation occurred aseismically.

  17. Multi-Temporal InSAR Analysis of Wenjiagou Landslide using Distributed Scatterers (United States)

    Wang, Chao; Zhang, Zhengjia; Zhang, Hong; Tang, Yixian


    This paper presents a multi-temporal InSAR method to monitor landslide movement at wenjiagou using Distributed Scatterers (DS). In this study, TDX and TSX bistatic SAR data are processed to obtain high precision DEM of the pose-landslide. DSs are efficiently identified using classified information and statistical characteristics. A series of Radarsat-2 HH polarization images collected in Wenjiagou from 2014.6 to 2014.9 are used to generate the deformation of the giant landslide. The experimental results show that there are obvious ground movement detected in the depositing area of the landslide during the observation.

  18. Error Modeling and Analysis for InSAR Spatial Baseline Determination of Satellite Formation Flying

    Directory of Open Access Journals (Sweden)

    Jia Tu


    Full Text Available Spatial baseline determination is a key technology for interferometric synthetic aperture radar (InSAR missions. Based on the intersatellite baseline measurement using dual-frequency GPS, errors induced by InSAR spatial baseline measurement are studied in detail. The classifications and characters of errors are analyzed, and models for errors are set up. The simulations of single factor and total error sources are selected to evaluate the impacts of errors on spatial baseline measurement. Single factor simulations are used to analyze the impact of the error of a single type, while total error sources simulations are used to analyze the impacts of error sources induced by GPS measurement, baseline transformation, and the entire spatial baseline measurement, respectively. Simulation results show that errors related to GPS measurement are the main error sources for the spatial baseline determination, and carrier phase noise of GPS observation and fixing error of GPS receiver antenna are main factors of errors related to GPS measurement. In addition, according to the error values listed in this paper, 1 mm level InSAR spatial baseline determination should be realized.

  19. Flood Mapping Using InSAR Coherence Map (United States)

    Selmi, S.; Ben Abdallah, W.; Abdelfatteh, R.


    Classic approaches for the detection of flooded areas are based on a static analysis of optical images and/or SAR data during and after the event. In this paper, we aim to extract the flooded zones by using the SAR image coupled with the InSAR coherence. A new formulation of the ratio approach for flood detection is given considering InSAR coherence. Our contribution is to take advantage from the coherence map provided using the InSAR pairs (one before and one after the event) to enhance the detection of flooded areas. We explore the fact that the coherence values during and after the flood are mainly differents on the flooded zones and we give a more suitable flood decision rule using this assumption. The proposed approach is tested and validated in the case of the flood taken place in 2005 in the region of Kef in Tunisia.

  20. InSAR Forensics: Tracing InSAR Scatterers in High Resolution Optical Image (United States)

    Wang, Yuanyuan; Zhu, XiaoXiang


    This paper presents a step towards a better interpretation of the scattering mechanism of different objects and their deformation histories in SAR interferometry (InSAR). The proposed technique traces individual SAR scatterer in high resolution optical images where their geometries, materials, and other properties can be better analyzed and classified. And hence scatterers of a same object can be analyzed in group, which brings us to a new level of InSAR deformation monitoring.

  1. An Analysis of Displacement Measurements for Lisbon, Portugal Using Combined InSAR and GNSS Data (United States)

    Roque, D.; Simonetto, E.; Falcao, A. P.; Perissin, D.; Durand, F.; Morel, L.; Fonseca, A. M.; Polidori, L.


    Atmospheric effects are still a limitation to the application of InSAR techniques for displacement measurement. In this study, zenith total delay (ZTD) values derived from global navigation satellite system (GNSS) are used to correct interferograms from tropospheric effects. Displacement measurements are obtained from the corrected interferograms through a persistent scatterer interferometry approach. The influence of different interpolation methods on the construction of ZTD maps is tested through two different algorithms: cubic spline and ordinary kriging. Differences are observed between the cumulative displacement maps obtained with both interpolators, but atmospheric effects are still present, possibly due to the small number of available GNSS stations.

  2. Integration of InSAR and GPS for hydraulic engineering

    Institute of Scientific and Technical Information of China (English)

    HE; XiuFeng; LUO; HaiBin; HUANG; QiHuan; HE; Min


    Interferometric synthetic aperture radar (InSAR) is a potential earth observation approach,and it has been demonstrated to have a variety of applications in measuring ground movement,urban subsidence and landslides.Currently InSAR provides the ability to map accurate DEM and measure ground deformation to sub-centimeter accuracy.However,many factors affect InSAR to measure ground movement since dam constructions are built in a large scale area with a complicated climate and unstable geology.This paper discusses potential applications of integrated InSAR and GPS to monitor a large-scale ground movement due to hydropower developments.The integration of InSAR and GPS can provide a cost-effective means for monitoring deformation of hydropower developments.Moreover,two novel methods,both the improved spatial interpolating method and estimation of 3D surface motion velocities method,are proposed and the experimental results and analysis are given in this paper.

  3. Obtaining digital elevation data in different terrain and physiognomy regions with spaceborne InSAR and its application analysis

    Institute of Scientific and Technical Information of China (English)


    Synthetic Aperture Radar Interferometry (for short, InSAR) is a new kind of earth observation technology, which has obtained great development in recent ten years and has a great development potential and successful future. In this note, three typical regions with different physiognomies and terrains have been selected as study regions to extract their Digital Elevation Model (DEMs). Compared with the existing 1︰250000 DEM and by analyzing their results, we have obtained its accuracy and applicable scopes. The results show that in the region (plains, mountains or highlands) with dry surface and sparse vegetation, because of the better correlatability of images, the DEM obtained by InSAR is evidently better than the existing 1︰250000 DEM and the accuracy can reach 4-6 m; in the thick-vegetation-covering region, correlatability between images descends and the accuracy of InSAR DEM can only reach about 30 m worse than its existing 1︰250000 DEM; in the middle covering field, the accuracy of InSAR DEM with tandem images can reach about 10 m as well; yet in water space, such as lakes and rivers, InSAR DEM shows a big error since there is only quite faint signal reflected to the sensor. Then the conclusion has been got: in the west of China, where it has a lack-vegetation and dry ground, InSAR is completely feasible to be applied to such a complicated nature environment region.

  4. Spatial-temporal heterogeneity of land subsidence evolution in Beijing based on InSAR and cluster analysis (United States)

    Ke, Y.; Li, Y.; Gong, H.; Pan, Y.; Zhu, L.; Chen, B.


    Land subsidence is a common natural hazard occurring in extensive areas in the world. In Beijing, the capital city of China, there has been serious land subsidence due to overexploitation of ground water during the recent decades. Five major subsidence tunnels have formed. Across the Beijing plain area, the ground is sinking at the rate of 30-100mm/year. Uneven subsidence leads to ground fissure and building destruction, and has caused great economical and property loss. To better characterize and understand regional land subsidence evolution, it is critical to monitor the time-series dynamics of subsidence, and capture the spatial-temporal heterogeneity of the subsidence evolution. Interferometric SAR technique, as it provides high spatial resolution and wide range of observation, have been successfully used to monitor regional ground deformation. The objective of this study is to derive time-series regional land subsidence dynamics in Beijing, and based on which, analyze and assess the spatial-temporal heterogeneity of the evolution using cluster analysis. First, ENVISAT ASAR (2003-2009 years, 28 scenes, track number: 218) datasets during 2003-2010 covering Beijing plain area were utilized to obtain time-series subsidence rate using Persistent Scatter InSAR (PS-InSAR) technique provided in SARProz software. Second, time-series subsidence characteristics of the PS points were analyzed and the PS points were clustered based on Self-Organization feature Maps (SOM) algorithm considering environmental factors such as groundwater level and lithologic characters. This study demonstrates that based on InSAR measurements and SOMs algorithm, the spatial-temporal heterogeneity of land subsidence evolution can be captured. Each cluster shows unique spatial-temporal evolution pattern. The results of this study will facilitate further land subsidence modeling and prediction at regional spatial scale.

  5. Integrated analysis of PALSAR/Radarsat-1 InSAR and ENVISAT altimeter data for mapping of absolute water level changes in Louisiana wetlands (United States)

    Kim, J.-W.; Lu, Zhiming; Lee, H.; Shum, C.K.; Swarzenski, C.M.; Doyle, T.W.; Baek, S.-H.


    Interferometric Synthetic Aperture Radar (InSAR) has been used to detect relative water level changes in wetlands. We developed an innovative method to integrate InSAR and satellite radar altimetry for measuring absolute or geocentric water level changes and applied the methodology to remote areas of swamp forest in coastal Louisiana. Coherence analysis of InSAR pairs suggested that the HH polarization is preferred for this type of observation, and polarimetric analysis can help to identify double-bounce backscattering areas in the wetland. ENVISAT radar altimeter-measured 18-Hz (along-track sampling of 417 m) water level data processed with regional stackfile method have been used to provide vertical references for water bodies separated by levees. The high-resolution (~ 40 m) relative water changes measured from ALOS PALSAR L-band and Radarsat-1 C-band InSAR are then integrated with ENVISAT radar altimetry to obtain absolute water level. The resulting water level time series were validated with in situ gauge observations within the swamp forest. We anticipate that this new technique will allow retrospective reconstruction and concurrent monitoring of water conditions and flow dynamics in wetlands, especially those lacking gauge networks. ?? 2009 Elsevier Inc.

  6. Pyroclastic Flow Deposits and InSAR: Analysis of Long-Term Subsidence at Augustine Volcano, Alaska

    Directory of Open Access Journals (Sweden)

    David B. McAlpin


    Full Text Available Deformation of pyroclastic flow deposits begins almost immediately after emplacement, and continues thereafter for months or years. This study analyzes the extent, volume, thickness, and variability in pyroclastic flow deposits (PFDs on Augustine Volcano from measuring their deformation rates with interferometric synthetic aperture radar (InSAR. To conduct this analysis, we obtained 48 SAR images of Augustine Volcano acquired between 1992 and 2010, spanning its most recent eruption in 2006. The data were processed using d-InSAR time-series analysis to measure the thickness of the Augustine PFDs, as well as their surface deformation behavior. Because much of the 2006 PFDs overlie those from the previous eruption in 1986, geophysical models were derived to decompose deformation contributions from the 1986 deposits underlying the measured 2006 deposits. To accomplish this, we introduce an inversion approach to estimate geophysical parameters for both 1986 and 2006 PFDs. Our analyses estimate the expanded volume of pyroclastic flow material deposited during the 2006 eruption to be 3.3 × 107 m3 ± 0.11 × 107 m3, and that PFDs in the northeastern part of Augustine Island reached a maximum thickness of ~31 m with a mean of ~5 m. Similarly, we estimate the expanded volume of PFDs from the 1986 eruption at 4.6 × 107 m3 ± 0.62 × 107 m3, with a maximum thickness of ~31 m, and a mean of ~7 m.

  7. InSAR Analysis of the 2011 Hawthorne (Nevada) Earthquake Swarm: Implications of Earthquake Migration and Stress Transfer (United States)

    Zha, X.; Dai, Z.; Lu, Z.


    The 2011 Hawthorne earthquake swarm occurred in the central Walker Lane zone, neighboring the border between California and Nevada. The swarm included an Mw 4.4 on April 13, Mw 4.6 on April 17, and Mw 3.9 on April 27. Due to the lack of the near-field seismic instrument, it is difficult to get the accurate source information from the seismic data for these moderate-magnitude events. ENVISAT InSAR observations captured the deformation mainly caused by three events during the 2011 Hawthorne earthquake swarm. The surface traces of three seismogenic sources could be identified according to the local topography and interferogram phase discontinuities. The epicenters could be determined using the interferograms and the relocated earthquake distribution. An apparent earthquake migration is revealed by InSAR observations and the earthquake distribution. Analysis and modeling of InSAR data show that three moderate magnitude earthquakes were produced by slip on three previously unrecognized faults in the central Walker Lane. Two seismogenic sources are northwest striking, right-lateral strike-slip faults with some thrust-slip components, and the other source is a northeast striking, thrust-slip fault with some strike-slip components. The former two faults are roughly parallel to each other, and almost perpendicular to the latter one. This special spatial correlation between three seismogenic faults and nature of seismogenic faults suggest the central Walker Lane has been undergoing southeast-northwest horizontal compressive deformation, consistent with the region crustal movement revealed by GPS measurement. The Coulomb failure stresses on the fault planes were calculated using the preferred slip model and the Coulomb 3.4 software package. For the Mw4.6 earthquake, the Coulomb stress change caused by the Mw4.4 event increased by ~0.1 bar. For the Mw3.9 event, the Coulomb stress change caused by the Mw4.6 earthquake increased by ~1.0 bar. This indicates that the preceding

  8. InSAR Time-Series Analysis of Land Subsidence under Different Land Use Types in the Eastern Beijing Plain, China

    Directory of Open Access Journals (Sweden)

    Chaofan Zhou


    Full Text Available In the Beijing plain, the long-term groundwater overexploitation, exploitation, and the utilization of superficial urban space have led to land subsidence. In this study, the spatial–temporal analysis of land subsidence in Beijing was assessed by using the small baseline subset (SBAS interferometric synthetic aperture radar (InSAR technique based on 47 TerraSAR-X SAR images from 2010 to 2015. Distinct variations of the land subsidence were found in the study regions. The maximum annual land subsidence rate was 146 mm/year from 2011 to 2015. The comparison between the SBAS InSAR results and the ground leveling measurements showed that the InSAR land subsidence results achieved a precision of 2 mm. In 2013, the maximum displacement reached 132 and 138 mm/year in the Laiguangying and DongbalizhuangDajiaoting area. Our analysis showed that the serious land subsidence mainly occurred in the following land use types: water area and wetland, paddy field, upland soils, vegetable land, and peasant-inhabited land. Our results could provide a useful reference for groundwater exploitation and urban planning.

  9. Monitoring Building Deformation with InSAR: Experiments and Validation. (United States)

    Yang, Kui; Yan, Li; Huang, Guoman; Chen, Chu; Wu, Zhengpeng


    Synthetic Aperture Radar Interferometry (InSAR) techniques are increasingly applied for monitoring land subsidence. The advantages of InSAR include high accuracy and the ability to cover large areas; nevertheless, research validating the use of InSAR on building deformation is limited. In this paper, we test the monitoring capability of the InSAR in experiments using two landmark buildings; the Bohai Building and the China Theater, located in Tianjin, China. They were selected as real examples to compare InSAR and leveling approaches for building deformation. Ten TerraSAR-X images spanning half a year were used in Permanent Scatterer InSAR processing. These extracted InSAR results were processed considering the diversity in both direction and spatial distribution, and were compared with true leveling values in both Ordinary Least Squares (OLS) regression and measurement of error analyses. The detailed experimental results for the Bohai Building and the China Theater showed a high correlation between InSAR results and the leveling values. At the same time, the two Root Mean Square Error (RMSE) indexes had values of approximately 1 mm. These analyses show that a millimeter level of accuracy can be achieved by means of InSAR technique when measuring building deformation. We discuss the differences in accuracy between OLS regression and measurement of error analyses, and compare the accuracy index of leveling in order to propose InSAR accuracy levels appropriate for monitoring buildings deformation. After assessing the advantages and limitations of InSAR techniques in monitoring buildings, further applications are evaluated.

  10. InSAR Scientific Computing Environment (United States)

    Gurrola, E. M.; Rosen, P. A.; Sacco, G.; Zebker, H. A.; Simons, M.; Sandwell, D. T.


    The InSAR Scientific Computing Environment (ISCE) is a software development effort in its second year within the NASA Advanced Information Systems and Technology program. The ISCE will provide a new computing environment for geodetic image processing for InSAR sensors that will enable scientists to reduce measurements directly from radar satellites and aircraft to new geophysical products without first requiring them to develop detailed expertise in radar processing methods. The environment can serve as the core of a centralized processing center to bring Level-0 raw radar data up to Level-3 data products, but is adaptable to alternative processing approaches for science users interested in new and different ways to exploit mission data. The NRC Decadal Survey-recommended DESDynI mission will deliver data of unprecedented quantity and quality, making possible global-scale studies in climate research, natural hazards, and Earth's ecosystem. The InSAR Scientific Computing Environment is planned to become a key element in processing DESDynI data into higher level data products and it is expected to enable a new class of analyses that take greater advantage of the long time and large spatial scales of these new data, than current approaches. At the core of ISCE is both legacy processing software from the JPL/Caltech ROI_PAC repeat-pass interferometry package as well as a new InSAR processing package containing more efficient and more accurate processing algorithms being developed at Stanford for this project that is based on experience gained in developing processors for missions such as SRTM and UAVSAR. Around the core InSAR processing programs we are building object-oriented wrappers to enable their incorporation into a more modern, flexible, extensible software package that is informed by modern programming methods, including rigorous componentization of processing codes, abstraction and generalization of data models, and a robust, intuitive user interface with

  11. InSAR Scientific Computing Environment (United States)

    Rosen, Paul A.; Sacco, Gian Franco; Gurrola, Eric M.; Zabker, Howard A.


    This computing environment is the next generation of geodetic image processing technology for repeat-pass Interferometric Synthetic Aperture (InSAR) sensors, identified by the community as a needed capability to provide flexibility and extensibility in reducing measurements from radar satellites and aircraft to new geophysical products. This software allows users of interferometric radar data the flexibility to process from Level 0 to Level 4 products using a variety of algorithms and for a range of available sensors. There are many radar satellites in orbit today delivering to the science community data of unprecedented quantity and quality, making possible large-scale studies in climate research, natural hazards, and the Earth's ecosystem. The proposed DESDynI mission, now under consideration by NASA for launch later in this decade, would provide time series and multiimage measurements that permit 4D models of Earth surface processes so that, for example, climate-induced changes over time would become apparent and quantifiable. This advanced data processing technology, applied to a global data set such as from the proposed DESDynI mission, enables a new class of analyses at time and spatial scales unavailable using current approaches. This software implements an accurate, extensible, and modular processing system designed to realize the full potential of InSAR data from future missions such as the proposed DESDynI, existing radar satellite data, as well as data from the NASA UAVSAR (Uninhabited Aerial Vehicle Synthetic Aperture Radar), and other airborne platforms. The processing approach has been re-thought in order to enable multi-scene analysis by adding new algorithms and data interfaces, to permit user-reconfigurable operation and extensibility, and to capitalize on codes already developed by NASA and the science community. The framework incorporates modern programming methods based on recent research, including object-oriented scripts controlling legacy and

  12. Earthquake relocations and InSAR time series analysis of the June 12th 2011 eruption of Nabro Volcano, Eritrea (United States)

    Hamlyn, J.; Keir, D.; Hammond, J. O.; Wright, T. J.; Neuberg, J.; Kibreab, A.; Ogubazghi, G.; Goitom, B.


    beneath neighbouring Mallahle volcanic caldera, despite no eruption occurring here. This may imply some form of co-dependent relationship within the magma system below both calderas. We also investigated temporal patterns, but none were apparent at this late stage of the eruption. In addition to this seismic data, InSAR acquisitions from the TerraSAR-X catalogue have also been processed. We will show a time series analysis of stripmap acquisitions over Nabro, taken immediately after the eruption in order to show areas of ground deformation. These will be compared to the spatial and temporal distribution of seismicity.

  13. Spatiotemporal Characterization of Land Subsidence and Uplift (2009–2010 over Wuhan in Central China Revealed by TerraSAR-X InSAR Analysis

    Directory of Open Access Journals (Sweden)

    Lin Bai


    Full Text Available The effects of ground deformation pose a significant geo-hazard to the environment and infrastructure in Wuhan, the most populous city in Central China, in the eastern Jianghan Plain at the intersection of the Yangtze and Han rivers. Prior to this study, however, rates and patterns of region-wide ground deformation in Wuhan were little known. Here we employ multi-temporal SAR interferometry to detect and characterize spatiotemporal variations of ground deformation in major metropolitan areas in Wuhan. A total of twelve TerraSAR-X images acquired during 2009–2010 are used in the InSAR time series analysis. InSAR-derived results are validated by levelling survey measurements and reveal a distinct subsidence pattern within six zones in major commercial and industrial areas, with a maximum subsidence rate up to −67.3 mm/year. A comparison analysis between subsiding patterns and urban developments as well as geological conditions suggests that land subsidence in Wuhan is mainly attributed to anthropogenic activities, natural compaction of soft soil, and karst dissolution of subsurface carbonate rocks. However, anthropogenic activities related to intensive municipal construction and industrial production have more significant impacts on the measured subsidence than natural factors. Moreover, remarkable signals of secular land uplift are found along both banks of the Yangtze River, especially along the southern bank, with deformation rates ranging mostly from +5 mm/year to +17.5 mm/year. A strong temporal correlation is highlighted between the detected displacement evolutions and the water level records of the Yangtze River, inferring that this previously unknown deformation phenomenon is likely related to seasonal fluctuations in water levels of the Yangtze River.

  14. InSAR Geodesy: The Next Phase (United States)

    Simons, M.


    Published in 1993, the first prominent geophysical applications of repeat pass Interferometric Synthetic Aperture Radar (InSAR) demonstrated spatially continuous imaging of the velocity of a remote ice stream in Antarctica and the ground displacement from a large earthquake in California. These studies heralded comprehensive assessments of rapid changes in the ice sheets and novel perspectives on earthquake source physics, all enabled by a new era in geodetic imaging with sub-centimeter sensitivity, meter-scale spatial resolution and expansive coverage. Since 1993, the promise of InSAR has been to provide deformation measurements "everywhere and all the time". Indeed, the new generation of satellites are already providing shorter revisit times and the gradual move to constellations of nearly identical satellites allows sub-weekly revisits at selected radar frequencies for many regions of interest. This increase in temporal sampling has prompted the geodetic community to develop a variety of InSAR time series methods and corrections techniques to mitigate the impact of path delays accrued in the atmosphere, all while inferring one or more components of the 3D time-dependent motions of Earth's solid surface. We illustrate these capabilities with recent studies that include detection of shallow aseismic slip transients on a major strike slip fault, dynamics of a subglacial eruption, the signature of aquifer management, mapping of rapid aseismic fault slip following a major earthquake and the long-distance response of ice stream motion to ocean tides. The increased sampling rate of observations allows us to improve our sensitivity to small amplitude deformation processes, separate overlapping physical processes by their different spatio-temporal signatures, and increase the general utility of imaging geodesy for rapid disaster response. At the same time, we need to rethink how data is managed for users with different capabilities - a critical challenge as we aim for a

  15. Performance Analysis of Flat Surface Assumption and Residual Motion Errors on Airborne Repeat-pass InSAR

    Directory of Open Access Journals (Sweden)

    Lin Xue


    Full Text Available When applying to the airborne repeat-pass Interferometric Synthetic Aperture Radar (InSAR, which has long synthetic aperture and large azimuth-dependent errors, the surface assumption used to simply the time-domain algorithm model and the residual motion errors due to the precision of the navigation system will affect the imaging result and the interferometric measurement. This paper analyzes the altitude errors introduced by the surface assumption and the residual motion errors due to the precision of the navigation system. We deduce the range errors model during the single pass and analyze the effects of these errors on the plane location, interferometric phase and DEM precision. Then the accuracy of the theoretical deduction is verified by simulation and real data. The research provides theoretical bases for the system design and signal processing of airborne repeat-pass InSAR.

  16. Confined aquifer head measurements and storage properties in the San Luis Valley, Colorado, from spaceborne InSAR observations (United States)

    Chen, Jingyi; Knight, Rosemary; Zebker, Howard A.; Schreüder, Willem A.


    Interferometric Synthetic Aperture Radar (InSAR), a remote sensing technique for measuring centimeter-level surface deformation, is used to estimate hydraulic head in the confined aquifer of the San Luis Valley (SLV), Colorado. Reconstructing head measurements from InSAR in agricultural regions can be difficult, as InSAR phase data are often decorrelated due to vegetation growth. Analysis of 17 L-band ALOS PALSAR scenes, acquired between January 2007 and March 2011, demonstrates that comprehensive InSAR deformation measurements can be recovered over the vegetated groundwater basin with an improved processing strategy. Local skeletal storage coefficients and time delays between the head change and deformation are estimated through a joint InSAR-well data analysis. InSAR subsidence estimates are transformed to head changes with finer temporal and spatial resolution than is possible using existing well records alone. Both InSAR and well data suggest that little long-term water-storage loss occurred in the SLV over the study period and that inelastic compaction was negligible. The seasonal head variations derived from InSAR are consistent with the existing well data at most locations where confined aquifer pumping activity dominates. Our results demonstrate the advantages of InSAR measurements for basin-wide characterization of aquifer storage properties and groundwater levels over agricultural regions.

  17. ALOS/PALSAR InSAR Time-Series Analysis for Detecting Very Slow-Moving Landslides in Southern Kyrgyzstan

    Directory of Open Access Journals (Sweden)

    Kanayim Teshebaeva


    Full Text Available This study focuses on evaluating the potential of ALOS/PALSAR time-series data to analyze the activation of deep-seated landslides in the foothill zone of the high mountain Alai range in the southern Tien Shan (Kyrgyzstan. Most previous field-based landslide investigations have revealed that many landslides have indicators for ongoing slow movements in the form of migrating and newly developing cracks. L-band ALOS/PALSAR data for the period between 2007 and 2010 are available for the 484 km2 area in this study. We analyzed these data using the Small Baseline Subset (SBAS time-series technique to assess the surface deformation related to the activation of landslides. We observed up to ±17 mm/year of LOS velocity deformation rates, which were projected along the local steepest slope and resulted in velocity rates of up to −63 mm/year. The obtained rates indicate very slow movement of the deep-seated landslides during the observation time. We also compared these movements with precipitation and earthquake records. The results suggest that the deformation peaks correlate with rainfall in the 3 preceding months and with an earthquake event. Overall, the results of this study indicated the great potential of L-band InSAR time series analysis for efficient spatiotemporal identification and monitoring of slope activations in this region of high landslide activity in Southern Kyrgyzstan.

  18. InSAR Scientific Computing Environment on the Cloud (United States)

    Rosen, P. A.; Shams, K. S.; Gurrola, E. M.; George, B. A.; Knight, D. S.


    In response to the needs of the international scientific and operational Earth observation communities, spaceborne Synthetic Aperture Radar (SAR) systems are being tasked to produce enormous volumes of raw data daily, with availability to scientists to increase substantially as more satellites come online and data becomes more accessible through more open data policies. The availability of these unprecedentedly dense and rich datasets has led to the development of sophisticated algorithms that can take advantage of them. In particular, interferometric time series analysis of SAR data provides insights into the changing earth and requires substantial computational power to process data across large regions and over large time periods. This poses challenges for existing infrastructure, software, and techniques required to process, store, and deliver the results to the global community of scientists. The current state-of-the-art solutions employ traditional data storage and processing applications that require download of data to the local repositories before processing. This approach is becoming untenable in light of the enormous volume of data that must be processed in an iterative and collaborative manner. We have analyzed and tested new cloud computing and virtualization approaches to address these challenges within the context of InSAR in the earth science community. Cloud computing is democratizing computational and storage capabilities for science users across the world. The NASA Jet Propulsion Laboratory has been an early adopter of this technology, successfully integrating cloud computing in a variety of production applications ranging from mission operations to downlink data processing. We have ported a new InSAR processing suite called ISCE (InSAR Scientific Computing Environment) to a scalable distributed system running in the Amazon GovCloud to demonstrate the efficacy of cloud computing for this application. We have integrated ISCE with Polyphony to

  19. InSAR data for monitoring land subsidence: time to think big (United States)

    Ferretti, A.; Colombo, D.; Fumagalli, A.; Novali, F.; Rucci, A.


    Satellite interferometric synthetic aperture radar (InSAR) data have proven effective and valuable in the analysis of urban subsidence phenomena based on multi-temporal radar images. Results obtained by processing data acquired by different radar sensors, have shown the potential of InSAR and highlighted the key points for an operational use of this technology, namely: (1) regular acquisition over large areas of interferometric data stacks; (2) use of advanced processing algorithms, capable of estimating and removing atmospheric disturbances; (3) access to significant processing power for a regular update of the information over large areas. In this paper, we show how the operational potential of InSAR has been realized thanks to the recent advances in InSAR processing algorithms, the advent of cloud computing and the launch of new satellite platforms, specifically designed for InSAR analyses (e.g. Sentinel-1a operated by the ESA and ALOS2 operated by JAXA). The processing of thousands of SAR scenes to cover an entire nation has been performed successfully in Italy in a project financed by the Italian Ministry of the Environment. The challenge for the future is to pass from the historical analysis of SAR scenes already acquired in digital archives to a near real-time monitoring program where up to date deformation data are routinely provided to final users and decision makers.

  20. Surface Subsidence Analysis by Multi-Temporal InSAR and GRACE: A Case Study in Beijing

    Directory of Open Access Journals (Sweden)

    Jiming Guo


    Full Text Available The aim of this study was to investigate the relationship between surface subsidence and groundwater changes. To investigate this relationship, we first analyzed surface subsidence. This paper presents the results of a case study of surface subsidence in Beijing from 1 August 2007 to 29 September 2010. The Multi-temporal Interferometric Synthetic Aperture Radar (multi-temporal InSAR technique, which can simultaneously detect point-like stable reflectors (PSs and distributed scatterers (DSs, was used to retrieve the subsidence magnitude and distribution in Beijing using 18 ENVISAT ASAR images. The multi-temporal InSAR-derived subsidence was verified by leveling at an accuracy better than 5 mm/year. Based on the verified multi-temporal InSAR results, a prominent uneven subsidence was identified in Beijing. Specifically, most of the subsidence velocities in the downtown area were within 10 mm/year, and the largest subsidence was detected in Tongzhou, with velocities exceeding 140 mm/year. Furthermore, Gravity Recovery and Climate Experiment (GRACE data were used to derive the groundwater change series and trend. By comparison with the multi-temporal InSAR-derived subsidence results, the long-term decreasing trend between groundwater changes and surface subsidence showed a relatively high consistency, and a significant impact of groundwater changes on the surface subsidence was identified. Additionally, the spatial distribution of the subsidence funnel was partially consistent with that of groundwater depression, i.e., the former possessed a wider range than the latter. Finally, the relationship between surface subsidence and groundwater changes was determined.

  1. Interferometric synthetic aperture radar (InSAR) and its applications to study volcanoes, part 1: Principles of InSAR (United States)

    Lu, Zhong; Zhang, Jixian; Zhang, Yonghong


    Interferometric synthetic aperture radar is an ability to measure the surface deformation of remote sensing technology, in a huge area, its deformation measurement with sub-centimeter accuracy, and spatial resolution in the tens of meters or less. In this paper, the basic theory of InSAR technology is reviewed, its working principle is clarified, and the related problems of surface deformation measurement using InSAR technology are discussed.

  2. Basin Scale Assessment of Landslides Geomorphological Setting by Advanced InSAR Analysis

    Directory of Open Access Journals (Sweden)

    Francesca Bozzano


    Full Text Available An extensive investigation of more than 90 landslides affecting a small river basin in Central Italy was performed by combining field surveys and remote sensing techniques. We thus defined the geomorphological setting of slope instability processes. Basic information, such as landslides mapping and landslides type definition, have been acquired thanks to geomorphological field investigations and multi-temporal aerial photos interpretation, while satellite SAR archive data (acquired by ERS and Envisat from 1992 to 2010 have been analyzed by means of A-DInSAR (Advanced Differential Interferometric Synthetic Aperture Radar techniques to evaluate landslides past displacements patterns. Multi-temporal assessment of landslides state of activity has been performed basing on geomorphological evidence criteria and past ground displacement measurements obtained by A-DInSAR. This step has been performed by means of an activity matrix derived from information achieved thanks to double orbital geometry. Thanks to this approach we also achieved more detailed knowledge about the landslides kinematics in time and space.

  3. InSAR time-series analysis of land subsidence due to groundwater overexploitation in groundwater basins of central and northeast Iran (United States)

    Sharifi, M.; Motagh, M.; Aipour, S.; Akbari, V.; Walter, T.; Rajabi, M.; Samadzadegan, F.; Djamour, Y.; Sedighi, M.


    We use Interferometric Synthetic Aperture (InSAR) observations acquired by the Envisat satellite during 2002-2008 to study land subsidence caused by groundwater over-exploitation in groundwater basins of central and northeast Iran. Earlier studies in these regions using a few interferograms showed rapid subsidence in the order of several centimetres per year. Here we use additional ENVISAT data and perform a time-series analysis using the small-baseline concept to better determine the temporal and spatial evolution of surface deformation.

  4. Detecting and monitoring UCG subsidence with InSAR

    Energy Technology Data Exchange (ETDEWEB)

    Mellors, R J; Foxall, W; Yang, X


    The use of interferometric synthetic aperture radar (InSAR) to measure surface subsidence caused by Underground Coal Gasification (UCG) is tested. InSAR is a remote sensing technique that uses Synthetic Aperture Radar images to make spatial images of surface deformation and may be deployed from satellite or an airplane. With current commercial satellite data, the technique works best in areas with little vegetation or farming activity. UCG subsidence is generally caused by roof collapse, which adversely affects UCG operations due to gas loss and is therefore important to monitor. Previous studies have demonstrated the usefulness of InSAR in measuring surface subsidence related to coal mining and surface deformation caused by a coal mining roof collapse in Crandall Canyon, Utah is imaged as a proof-of-concept. InSAR data is collected and processed over three known UCG operations including two pilot plants (Majuba, South Africa and Wulanchabu, China) and an operational plant (Angren, Uzbekistan). A clear f eature showing approximately 7 cm of subsidence is observed in the UCG field in Angren. Subsidence is not observed in the other two areas, which produce from deeper coal seams and processed a smaller volume. The results show that in some cases, InSAR is a useful tool to image UCG related subsidence. Data from newer satellites and improved algorithms will improve effectiveness.

  5. InSAR analysis of the crustal deformation affecting the megacity of Istanbul: the results of the FP7 Marsite Project as a GEO Supersite Initiative (United States)

    Solaro, Giuseppe; Bonano, Manuela; Manzo, Mariarosaria


    The North Anatolian Fault (NAF) is one of the most active faults worldwide, extending approximately 1,200 km from Eastern Turkey to the Northern Aegean Sea. During the 20th century series of damaging earthquakes occurred along the NAF, generally propagated westward towards Istanbul; the last one occurred in 1999 at Izmit, a city 80 km away from Istanbul. Within this scenario, the FP7 MARsite project (New Directions in Seismic Hazard assessment through Focused Earth Observation in Marmara Supersite), supported by EU, intends to collect, share and integrate multidisciplinary data (seismologic, geochemical, surveying, satellite, etc.) in order to carry out assessment, mitigation and management of seismic risk in the region of the Sea of Marmara. In the framework of the MARsite project, we performed the analysis and monitoring of the surface deformation affecting the Istanbul mega city by exploiting the large archives of X-band satellite SAR data, made available through the Supersites Initiatives, and by processing them via the advanced multi-temporal and multi-scale InSAR technique, known as the Small BAseline Subset (SBAS) approach. In particular, we applied the SBAS technique to a dataset of 101 SAR images acquired by the TerraSAR-X constellation of the German Space Agency (DLR) over descending orbits and spanning the November 2010 - August 2014 time interval. From,these images, we generated 312 differential interferograms with a maximum spatial separation (perpendicular baseline) between the acquisition orbits of about 500 m., that were used to generate, via the SBAS approach, mean deformation velocity map and corresponding ground time series of the investigated area. The performed InSAR analysis reveals a generalized stability over the Istanbul area, except for some localized displacements, related to subsidence and slope instability phenomena. In particular, we identified: (i) a displacement pattern related to the Istanbul airport, showing a mostly linear

  6. InSAR Time Series Analysis of Natural and Anthropogenic Coastal Plain Subsidence: The Case of Sibari (Southern Italy

    Directory of Open Access Journals (Sweden)

    Giuseppe Cianflone


    Full Text Available We applied the Small Baseline Subset multi-temporal InSAR technique (SBAS to two SAR datasets acquired from 2003 up to 2013 by Envisat (ESA, European Space Agency and COSMO-SkyMed (ASI, Italian Space Agency satellites to investigate spatial and temporal patterns of land subsidence in the Sibari Plain (Southern Italy. Subsidence processes (up to ~20 mm/yr were investigated comparing geological, hydrogeological, and land use information with interferometric results. We suppose a correlation between subsidence and thickness of the Plio-Quaternary succession suggesting an active role of the isostatic compensation. Furthermore, the active back thrusting in the Corigliano Gulf could trigger a flexural subsidence mechanism even if fault activity and earthquakes do not seem play a role in the present subsidence. In this context, the compaction of Holocene deposits contributes to ground deformation. Despite the rapid urbanization of the area in the last 50 years, we do not consider the intensive groundwater pumping and related water table drop as the main triggering cause of subsidence phenomena, in disagreement with some previous publications. Our interpretation for the deformation fields related to natural and anthropogenic factors would be a comprehensive and exhaustive justification to the complexity of subsidence processes in the Sibari Plain.

  7. InSAR imagery pattern matching validation for landslide assessment (United States)

    Serbulea, Manole-Stelian; Gogu, Radu; Teleaga, Delia; Marcel Manoli, Daniel; Priceputu, Adrian; Gaitanaru, Dragos Stefan; Ungureanu, Constantin; Anghel, Alexandra; Andronic, Adrian; Niculescu, Alexandru; Liviu Bugea, Adrian


    The need for identifying over large areas ongoing instability phenomena and spotting the old ones pushed the boundaries of geotechnical engineering from numerical modeling and point-wise in-situ measurements towards geodesic and geographic sciences. Regardless of the ground-based monitoring techniques' precision and reliability, a larger scale monitoring is often useful to either better correlate the scattered results or to identify additional monitoring points. Using aerial ortho-photogrammetry and site visit recognition represent a good, yet costly method to obtain qualitative information about old inactive landslides. A more suitable approach is using ground-based or satellite radar interferometry (InSAR). The obvious disadvantage of the ground-based system is that the monitoring has to be carried out on a predetermined site while the space-borne system may be set to collect information from various sites in range by each successive passing. The quantitative results acquired through the means of InSAR provide a precise set of information regarding the soil surface displacement, with high accuracy and reliability. They provide a great means of identifying danger zones as well as a way of calibrating and augmenting the classical monitoring techniques. This work describes the possibility of integrating the InSAR measurements with the ground monitoring techniques to identify landslide occurrence hazard and reveal the whole of affected areas even when minute symptoms develop. One of the objectives is to propose InSAR monitoring as a fast and efficient mapping tool to help authorities minimize the damage produced by landslides. It can also provide engineers and scientists additional information to further study landslides dynamics phenomena (such as propagation). Interferometry on SAR data uses phase values from two radar images. When a point changes position, the distance between it and the sensor alters, modifying the phase of the signal. This change is used to

  8. Geodetic imaging of tectonic deformation with InSAR (United States)

    Fattahi, Heresh

    Precise measurements of ground deformation across the plate boundaries are crucial observations to evaluate the location of strain localization and to understand the pattern of strain accumulation at depth. Such information can be used to evaluate the possible location and magnitude of future earthquakes. Interferometric Synthetic Aperture Radar (InSAR) potentially can deliver small-scale (few mm/yr) ground displacement over long distances (hundreds of kilometers) across the plate boundaries and over continents. However, Given the ground displacement as our signal of interest, the InSAR observations of ground deformation are usually affected by several sources of systematic and random noises. In this dissertation I identify several sources of systematic and random noise, develop new methods to model and mitigate the systematic noise and to evaluate the uncertainty of the ground displacement measured with InSAR. I use the developed approach to characterize the tectonic deformation and evaluate the rate of strain accumulation along the Chaman fault system, the western boundary of the India with Eurasia tectonic plates. I evaluate the bias due to the topographic residuals in the InSAR range-change time-series and develope a new method to estimate the topographic residuals and mitigate the effect from the InSAR range-change time-series (Chapter 2). I develop a new method to evaluate the uncertainty of the InSAR velocity field due to the uncertainty of the satellite orbits (Chapter 3) and a new algorithm to automatically detect and correct the phase unwrapping errors in a dense network of interferograms (Chapter 4). I develop a new approach to evaluate the impact of systematic and stochastic components of the tropospheric delay on the InSAR displacement time-series and its uncertainty (Chapter 5). Using the new InSAR time-series approach developed in the previous chapters, I study the tectonic deformation across the western boundary of the India plate with Eurasia and

  9. Earthquake Cycle Deformation at the Ballenas Transform, Gulf of California, Mexico, from InSAR and GPS Measurements (United States)

    Plattner, Christina; Fattahi, Heresh; Malservisi, Rocco; Amelung, Falk; Verdecchia, Alessandro; Dixon, Timothy H.


    We study crustal deformation across the Ballenas marine channel, Gulf of California, Mexico using InSAR and campaign GPS data. Interseismic velocities are calculated by time-series analysis spanning five years of data. Displacements from the August 3rd 2009 Mw 6.9 earthquake are calculated by differencing the most recent observations before and after the event. To estimate the offset across the marine channel we calibrate the InSAR velocity and displacement fields using the corresponding GPS data. Unfortunately, the InSAR interseismic velocity field is affected by residual tropospheric delay. We interpret the GPS interseismic and the GPS and InSAR coseismic deformation data using dislocation modeling and compare the fault kinematics during these periods of the earthquake cycle.

  10. A Global Optimal Coherence Method for Multi-baseline InSAR Elevation Inversion

    Directory of Open Access Journals (Sweden)

    HUA Fenfen


    Full Text Available A global optimal coherence method for elevation inversion from multi-baseline polarimetric InSAR data is proposed. The multi-baseline polarimetric InSAR data used in experiments were obtained by Chinese X-SAR system and Germany's E-SAR system. Through combining several full polarimetric InSAR images, the proposed method constructs the multi-baseline polarimetric InSAR coherency matrix, and solves the optimal interferograms under global optimal coherence criterion. The optimal interferograms generated by global optimal coherence method were used to calculate the elevation of target with multi-baseline InSAR elevation inversion method. The proposed method reduces the influence of different scattering centers effectively using multi-baseline InSAR, which improves the accuracy and reliability of the interferometric phase and eventually improves the accuracy of DEM. The results verify the validity of the proposed method.

  11. InSAR analysis of aquifer-system response to 20 years of mine-dewatering in the Carlin gold trend, north-central Nevada (United States)

    Bell, J. W.; Katzenstein, K.


    The Carlin trend in north-central Nevada has the second largest gold resources in the world, most of it produced from large open-pit mines. Heavy groundwater dewatering is required at the mines to lower water levels below the depth of mining which can exceed 400-500 m. The resulting water level declines have produced surface deformation (subsidence) that can be detected and modeled with InSAR to characterize the aquifer-system response and to estimate hydraulic parameters in order to test and refine groundwater models. In a series of studies we examined the effects of dewatering at mines operated by Newmont Mining Corporation and Barrick Gold of North America near Battle Mountain and Carlin, Nevada. The Lone Tree mine operated a large-scale dewatering program between 1992-2006 using deep bedrock wells that pumped between 64-92 hm3/yr (52,000-75,000 acre-ft/yr) and lowered bedrock water levels more than 120 m. InSAR analysis of ERS and Envisat data for the 1992-2000 and 2004-2010 periods showed that as much as 50 cm of aquifer-system compaction occurred in bedrock and in alluvial basin deposits with subsidence rates ranging between 3-6 cm/yr. Since dewatering ended in late 2006 and water levels began rising, only 7 cm of aquifer-system recovery (uplift) has occurred as of 2010 suggesting that most of the aquifer-system compaction was likely inelastic, apparently in the pumped fractured bedrock. The InSAR subsidence data differ significantly from the pre-pumping groundwater model which predicted 2.5 m of subsidence for the 1992-2000 period. The results yield bulk storage coefficients in the range of 7 x 10-3 to 5.6 x 10-5 with a most frequent value of 1.0 x 10-3 (Baffoe-Twum, 2007), InSAR-derived hydraulic values that can provide better constraints on specific storage estimates in future groundwater models. The Betze-Post mine has been dewatering continually since late 1989 with maximum pumping rates of greater than 140 hm3/yr (110,000 acre-ft/yr) in the early and

  12. Precision estimation and geomorphological analysis based on the DEM generated by InSAR: Taking Damxung-Yangbajain area as an example

    Institute of Scientific and Technical Information of China (English)

    Yaqiong Dai; Jinwei Ren; Xuhui Shen; Jingfa Zhang; Shunying Hong


    Digital elevation model (DEM) can be generated by interferometric synthetic aperture radar (InSAR). In this paper, the interferometric processing and analyses are carried out for Damxung-Yangbajain area in Tibet, using a pair of Europe remote-sensing satellite (ERS)-l/2 tandem SAR images acquired on 6 and 7 April 1996. A portion of the In-SAR-derived DEM is selected and compared with the 1:50 000 DEM to determine the precision of the InSAR-derived DEM. The comparison indicates that the root mean squared errors (RMSE), which are used to evaluate error, are about 35, 60, 10, and 15 m in the studied area, mountainous area, basin area and near-fault area, respectively, suggesting that obvious errors are mainly in mountainous area. Besides, the limitation of InSAR technology to generate DEM is analyzed. Our investigation shows that InSAR is an effective tool in geodesy and an important complement to field surveying in some dangerous areas.

  13. Earthquake relocations and InSAR analysis following the June 12th 2011 eruption of Nabro volcano, Afar (United States)

    Hamlyn, Joanna; Wright, Tim; Keir, Derek; Neuberg, Jurgen; Grandin, Raphael; Goitom, Berhe; Hammond, James; Kibreab, Alem; Ogubazghi, Ghebrebrhan; Pagli, Carolina; Sansosti, Eugenio


    subsidence signal, but the time series shows a shorter wavelength fluctuation of ground deformation, which is not apparent in the TSX data. We processed the seismic signals detected by the temporary local network and by a seismic station within a permanent regional array, to provide hypocentre locations for the period September-October, 2011. We used Hypoinverse-2000 to provide preliminary locations for events, which were then relocated using HypoDD. Absolute error after Hypoinverse-2000 processing was approximately ±2 and ±4 km in the horizontal and the vertical directions, respectively. Using HypoDD, relative errors were reduced to ±20 and ±30 m in the horizontal and vertical directions, respectively. The hypocentres show clusters of activity as well as aseismic regions. The majority of the earthquakes are located at the active vent, with fewer events located on the flanks. There is a smaller cluster of events to the south-west of Nabro beneath neighbouring Mallahle volcanic caldera, despite no eruption occurring here nor any post-eruptive deformation. This may imply some stress triggering mechanism or some pressure connection between the magma system of the two calderas. We present both the seismic and InSAR datasets as a joint approach to understand this eruption, as well as further implications for other 'quiet calderas'.

  14. Permanent scatterer InSAR processing: Forsmark

    Energy Technology Data Exchange (ETDEWEB)

    Dehls, John F. [Geological Survey of Norway, Trondheim (Norway)


    It has been speculated that slow, aseismic movement may be occurring along some of the fracture zones crosscutting the Forsmark area. The purpose of this study is to determine if it is possible to measure such movement using dInSAR. Differential SAR Interferometry (DInSAR) is a technique that compares the phases of multiple radar images of an area to measure surface change. The method has the potential to detect millimetric surface deformation along the sensor - target line-of-sight. Differences in phase between two images are easily viewed by combining, or interfering, the two phase-images. In the resulting image, the waves will either reinforce or cancel one another, depending upon the relative phases. The resulting image is called an interferogram and contains concentric bands of colour, or fringes, that are related to topography and/or surface deformation. New algorithms use many images acquired over a long time period to determine the movement history of individual objects, referred to as permanent scatterers. In the current project, standard PSInSAR processing was performed on 40 ERS-1 and ERS-2 scenes. The total area processed is approximately 1,500 km{sup 2}. Slightly less than 20,000 permanent scatterers were identified.The highest densities were obtained along the coast and on the islands, where natural outcrops are more abundant. Two main classes of objects act as permanent scatterers in this area. The first are natural reflectors, such as rocks. The second are man-made reflectors, such as parts of buildings. Numerous local movements were found in the study area, relating to building subsidence, or compaction of anthropogenic fill. The dataset was divided into three groups for analysis, based upon the location of regional lineaments provided by SKB. Both statistical and geostatistical techniques were used. The median velocity of the three blocks did not differ by more than 0.2 mm/yr. This is not considered significant, given the possible magnitude of

  15. Source mechanism analysis of strong mining induced seismic event and its influence on ground deformation observed by InSAR technique. (United States)

    Rudzinski, Lukasz; Mirek, Katarzyna; Mirek, Janusz


    On April 17th, 2015 a strong shallow seismic event M4.0 struck a mining panel in the Wujek-Slask coal mine, southern Poland. The event was widely felt, followed with rockburst and caused a strong damages inside mining corridors. Unfortunately two miners are trapped by tunnels collapse. Full Moment Tensor (MT) estimated with regional broad-band signals shows that the event was characterized with very high isotropic (implosive) part. Mining inspections verified the occurrence of a rockfall and floor uplift. Very shallow foci depth (less than 1000m) and collapse - like MT solution suggest that event could be responsible for surface deformation in the vicinity of epicenter. To verified this issue we used the Interferometric Synthetic Aperture Radar technique (InSAR). The InSAR relies on measuring phase differences between two SAR images (radarograms). The measured differences may be computed into a single interferometric image. i.e. an interferogram. Interferogram computed from two radarograms of the same terrain taken at different time allows detecting changes in elevation of the terrain. Two SAR scenes acquired by Sentinel-1 satellite (European Space Agency) were processed to obtain the interferogram covered study area (12.04.2015 and 24.04.2015). 12 days interval differential interferogram shows distinctive concentric feature which indicate subsidence trough. Subsidence pattern shows 1 cycle of deformation corresponding with about 2.5 cm subsidence. The InSAR solution support the reliability of very strong implosive MT part.

  16. Hydrodynamics of the groundwater-fed Sian Ka'an Wetlands, Mexico, From InSAR and SAR Data

    DEFF Research Database (Denmark)

    Gondwe, Bibi Ruth Neuman; Hong, S.; Wdowinski, S.


    to understand, quantify and predict the wetland dynamics. Remotely sensed Interferometric Synthetic Aperture Radar (InSAR) and Synthetic Aperture Radar (SAR) data offer new opportunities to get hydrodynamic information, which is useful for wetland management. InSAR data produces temporal phase......-changes of the backscattered radar signal, which can be related to the water level changes in vegetated wetlands. SAR data reveals information of surface properties such as the degree of flooding through the amplitude of the backscattered signal. We used RADARSAT-1 InSAR and SAR data to form 36 interferograms and 13 flooding...

  17. InSAR Scientific Computing Environment - The Home Stretch (United States)

    Rosen, P. A.; Gurrola, E. M.; Sacco, G.; Zebker, H. A.


    The Interferometric Synthetic Aperture Radar (InSAR) Scientific Computing Environment (ISCE) is a software development effort in its third and final year within the NASA Advanced Information Systems and Technology program. The ISCE is a new computing environment for geodetic image processing for InSAR sensors enabling scientists to reduce measurements directly from radar satellites to new geophysical products with relative ease. The environment can serve as the core of a centralized processing center to bring Level-0 raw radar data up to Level-3 data products, but is adaptable to alternative processing approaches for science users interested in new and different ways to exploit mission data. Upcoming international SAR missions will deliver data of unprecedented quantity and quality, making possible global-scale studies in climate research, natural hazards, and Earth's ecosystem. The InSAR Scientific Computing Environment has the functionality to become a key element in processing data from NASA's proposed DESDynI mission into higher level data products, supporting a new class of analyses that take advantage of the long time and large spatial scales of these new data. At the core of ISCE is a new set of efficient and accurate InSAR algorithms. These algorithms are placed into an object-oriented, flexible, extensible software package that is informed by modern programming methods, including rigorous componentization of processing codes, abstraction and generalization of data models. The environment is designed to easily allow user contributions, enabling an open source community to extend the framework into the indefinite future. ISCE supports data from nearly all of the available satellite platforms, including ERS, EnviSAT, Radarsat-1, Radarsat-2, ALOS, TerraSAR-X, and Cosmo-SkyMed. The code applies a number of parallelization techniques and sensible approximations for speed. It is configured to work on modern linux-based computers with gcc compilers and python

  18. UAVSAR and TerraSAR-X Based InSAR Detection of Localized Subsidence in the New Orleans Area (United States)

    Blom, R. G.; An, K.; Jones, C. E.; Latini, D.


    Vulnerability of the US Gulf coast to inundation has received increased attention since hurricanes Katrina and Rita. Compounding effects of sea level rise, wetland loss, and regional and local subsidence makes flood protection a difficult challenge, and particularly for the New Orleans area. Key to flood protection is precise knowledge of elevations and elevation changes. Analysis of historical and continuing geodetic measurements show surprising complexity, including locations subsiding more rapidly than considered during planning of hurricane protection and coastal restoration projects. Combining traditional, precise geodetic data with interferometric synthetic aperture radar (InSAR) observations can provide geographically dense constraints on surface deformation. The Gulf Coast environment is challenging for InSAR techniques, especially with systems not designed for interferometry. We use two InSAR capable systems, the L- band (24 cm wavelength) airborne JPL/NASA UAVSAR, and the DLR/EADS Astrium spaceborne TerraSAR X-band (3 cm wavelength), and compare results. First, we are applying pair-wise InSAR to the longer wavelength UAVSAR data to detect localized elevation changes potentially impacting flood protection infrastructure from 2009 - 2014. We focus on areas on and near flood protection infrastructure to identify changes indicative of subsidence, structural deformation, and/or seepage. The Spaceborne TerraSAR X-band SAR system has relatively frequent observations, and dense persistent scatterers in urban areas, enabling measurement of very small displacements. We compare L-band UAVSAR results with permanent scatterer (PS-InSAR) and Short Baseline Subsets (SBAS) interferometric analyses of a stack composed by 28 TerraSAR X-band images acquired over the same period. Thus we can evaluate results from the different radar frequencies and analyses techniques. Preliminary results indicate subsidence features potentially of a variety of causes, including ground water

  19. Integration of GPS and InSAR Data for Optimal 3-Dimensional Crustal Deformation Map (United States)

    Shen, Z.; Liu, Z.


    GPS and InSAR are complementary to each other for crustal deformation monitoring, We develop an algorithm to integrate the two data sets for the production of 3-dimensional crustal motion map. In the algorithm point-based discrete GPS measurements are first interpolated to produce continuous 3-D vector map at chosen grids covered by the InSAR data. The interpolation is based on an algorithm of Shen et al. [2015], which takes into account of GPS station distance, network density and configuration for data weighting. A Gaussian distance weighting function and a Voronoi cell spatial weighting function are used in the interpolation. The amount of weighting and degree of smoothing can be spatially variable and optimally determined based on in situ data strength. This approach can effectively smooth out the incoherencies in discretized GPS velocity data. At the locations where both InSAR and interpolated GPS data are available, optimal 3-D components are solved for using a weighted least square method. The InSAR data are weighted by their LOS uncertainties. The GPS interpolated data are weighted by their re-estimated uncertainties assuming a uniform smoothing instead of variable smoothing used for data interpolation as mentioned above, to ensure that the uncertainty estimates reflect the in situ data strength consistently and not biased by uneven degree of smoothing. Including InSAR data from both ascending and descending viewing geometry, if available, provides improved constraint on the 3-D deformation when integrating with GPS data. We apply this algorithm to a test region in southern California covering most of the active faults in the region such as the San Andreas, San Jacinto, and Garlock. We use LOS rate data derived from 18 years of ERS-Envisat InSAR data, and a combination of continuous and campaign GPS data of more than two decades of time span. Our preliminary result shows that the GPS and InSAR data are generally consistent for the horizontal velocities at

  20. Monitoring of Land Deformation Due to Oil Production by InSAR Time Series Analysis Using PALSAR Data in Bolivarian Republic of Venezuela (United States)

    Deguchi, Tomonori; Narita, Tatsuhiko


    The target area of this study is the Maracaibo sedimentary basin located in the western part of Bolivarian Republic of Venezuela. The full-scale exploration and development for oil resources in Venezuela which was the greatest oil-producing country in South America had begun at the Maracaibo sedimentary basin in the 1910s, and it was a center of the oil product in Venezuela until the 1980s. But, in most of oil fields in the Maracaibo sedimentary basin, there is concern over the drain on recoverable reserves due to deterioration, and the production amount of petroleum in Venezuela has been diminishing these days. Leveling and GPS surveying were carried out in the past, and they revealed that the large-scale subsidence phenomenon of which cumulative subsidence amount was approximately 5 meter had occurred. The authors applied the vertical displacement measurement by InSAR time series analysis using PALSAR data obtained in the Fine-beam and ScanSAR observation mode. As a result, it could be confirmed clear ground deformation in the surrounding of three oil fields (Tia Juana, Lagunillas and Bachaquero) and easily recognized that the areas of phase anomalies detected by this analysis had expanded and the number of interference fringes had increased over time. The annual velocity of vertical ground surface displacement measured by InSAR time series analysis was -51 mm per year, -103 mm per year and -58 mm per year in Tia Juana, Lagunillas and Bachaquero oil field respectively. The tendency that an earth surface shifted towards the center of phase anomalies was detected from the result of the horizontal ground change measurement. It was interpreted from Google Earth and Landsat images that oil-related facilities (mainly bowling stations) were built intensively over the areas where phase anomalies were detected. Therefore, it was inferred that there was a high association between the operation activity of the oil field and ground deformation. In addition, the deterioration

  1. InSAR Time Series Analysis and Geophysical Modeling of City Uplift Associated with Geothermal Drillings in Staufen im Breisgau, Germany (United States)

    Motagh, M.; Lubitz, C.


    Geothermal energy is of increasing importance as alternative, environmentally friendly technology for heat management. Direct interaction with the subsurface requires careful implementation, in particular in geological complex regions. The historical city Staufen im Breisgau, SW Germany, has attracted national attention as a case of implementation failure with severe consequences, causing debates on the applicability and security of this sustainable technique. Located at the eastern transition zone of the Upper Rhine Graben and the Schwarzwald massif, the geothermal potential is high at Staufen due to strong temperature gradients. In September 2007, seven boreholes for geothermal probes were drilled up to a depth of 140 m to provide a new heat management for the city hall. Within five years an uplift phenomenon has been observed in Staufen reaching more than 40 cm in places and 269 buildings were damaged. Hydro-chemical driven anhydrite-gypsum transformation in the subsurface was identified as the cause leading to volume increase that is observable as surface uplift. This process is associated with the geothermal drilling activities that have crossed several groundwater levels. In this work, we summarize and present the findings of spaceborne Synthetic Aperture Radar Interferometry (InSAR) analysis of the uplift in Staufen over the last five years from July 2008 through July 2013. By applying the Small Baseline Subset (SBAS) method, we find a localized elliptical-shaped deformation field in NE-SW orientation. Area of maximum uplift is located 50 m NNE of the drilling zone. At this location, we observe a cumulative uplift of approx. 13.7 cm ± 0.34 cm (mean value within an area of 30 m by 30 m) from July 2008 to July 2009, which reduced to cumulative uplift of 3 cm ± 0.25 cm from July 2012 to July 2013. The deceleration can be related to applied countermeasures as borehole sealing and groundwater pumping. The observed ground surface response was compared to

  2. Answering the right question - integration of InSAR with other datasets (United States)

    Holley, Rachel; McCormack, Harry; Burren, Richard


    The capabilities of satellite Interferometric Synthetic Aperture Radar (InSAR) are well known, and utilized across a wide range of academic and commercial applications. However there is a tendency, particularly in commercial applications, for users to ask 'What can we study with InSAR?'. When establishing a new technique this approach is important, but InSAR has been possible for 20 years now and, even accounting for new and innovative algorithms, this ground has been thoroughly explored. Too many studies conclude 'We show the ground is moving here, by this much', and mention the wider context as an afterthought. The focus needs to shift towards first asking the right questions - in fields as diverse as hazard awareness, resource optimization, financial considerations and pure scientific enquiry - and then working out how to achieve the best possible answers. Depending on the question, InSAR (and ground deformation more generally) may provide a large or small contribution to the overall solution, and there are usually benefits to integrating a number of techniques to capitalize on the complementary capabilities and provide the most useful measurements. However, there is still a gap between measurements and answers, and unlocking the value of the data relies heavily on appropriate visualization, integrated analysis, communication between technique and application experts, and appropriate use of modelling. We present a number of application examples, and demonstrate how their usefulness can be transformed by moving from a focus on data to answers - integrating complementary geodetic, geophysical and geological datasets and geophysical modeling with appropriate visualization, to enable comprehensive solution-focused interpretation. It will also discuss how forthcoming developments are likely to further advance realisation of the full potential satellite InSAR holds.

  3. The InSAR Italy portal for open access to crustal deformation data (United States)

    Salvi, Stefano; Tolomei, Cristiano; Pezzo, Giuseppe; Lanari, Riccardo; Pepe, Antonio; Marchetti, Pier Giorgio; Della Vecchia, Andrea; Mantovani, Simone


    InSAR Italy is a web portal devised to provide open access services to crustal deformation data measured using multitemporal SAR Interferometry techniques over the Italian territory. It is an evolution of the VELISAR initiative, promoted in 2006 by the Istituto Nazionale di Geofisica e Vulcanologia, and originally participated by IREA-CNR and TRE srl. InSAR Italy was developed tailoring the Multi-sensor Evolution Analysis (MEA) environment, an Earth Observation and geospatial data analysis tool empowered with OGC standard interfaces. The web interface allows an easy browsing of the ground deformation maps obtained for each satellite image dataset, leading to a clear picture and improved analysis of the displacement time series over single pixels or large areas. Web Coverage Service (WCS) and Web Coverage Processing Service (WCPS) are used to access and process the maps, respectively. The crustal deformation data are provided by INGV and IREA-CNR as products of publicly-funded research projects, and are disseminated in compliance with the national legislation on the Open Data Access; metadata associated to the products are published according to the INSPIRE specifications. The information provided through InSAR Italy is mainly based on InSAR data maintained in the ESA archives, in particular from the ERS satellites for the 1992-2000 period, and ENVISAT for the period 2003-2010, however, ground velocity maps obtained from COSMO-SkyMed data will also be released in the near future. The InSAR Italy deformation maps consist of time series of ground displacement at resolution varying between 5 and 80 m, and the relative mean velocity values. The data sets can be queried and mean velocities can be recalculated over user-defined time periods, to account for possible non-linear displacement trends. The MEA spatiotemporal data analysis capability allows to investigate deformation phenomena occurring at very different spatial scales, from single buildings to entire regions

  4. InSAR analysis of diking and incipient oceanic spreading in the Danakil depression of the northern Afar rift (United States)

    Gomez, F. G.; Tesfaye, S.


    The Danakil depression in the northern part of the Afar rift is a location of incipient oceanic spreading. Deformation associated with recent magmatic events provides a view of the incremental stages in rifting. Using Interferometric Synthetic Aperture Radar (InSAR) and geodetic modeling, this study assesses magmatic events that occurred in October 2004 and November 2008 in the axial graben of the Danakil depression. The study utilized C-band Envisat ASAR imagery and L-band ALOS PALSAR imagery. Both events involve deflation of magma chambers and intrusion of NNW-SSE striking dikes. The 2004 event took place in the Dallol area and involved ~5 km deep magmatic source and a SSE-propagating dike that opens approximately 80 - 120 cm - this contrasts with seismological results suggesting a 20 km depth with primarily normal faulting. The 2008 event occurred on the northern segment of the Erta Ale volcanic range between Alu and Dalafillal volcanic centers. Available image data permitted assessing pre- and post-event deformation, as well as the main eruption. Interferograms spanning the 2008 eruption image the deflation of a 3 - 4 km deep magmatic source, as well as dilatation of a SSE-striking dike. Additionally, the erupted lava flow is evident as a decorrelated region along the northeast flank of the fissure event. Prior to the eruption, the inflation of the magmatic chamber is imaged, and after the eruption, resurgence of the magma chamber is also documented. Furthermore, post-eruption interferograms also document the contraction and cooling of the lava flow, which facilitates 1-dimensional modeling of the thickness of the flow and calculation of the volume of the effusive component of the eruption. In both cases, aseismic deformation dominates - i.e., the seismologically measured moment is significantly less than the geodetically observed moment: ~25% for the 2004 event and 10% for the 2008 event. Magnitudes of incremental extension are then compared with regional

  5. Utilization of InSAR differential interferometry for surface deformation detection caused by mining

    Energy Technology Data Exchange (ETDEWEB)

    Yang, F. [Liaoning Technical Univ., Fuxin (China). School of Geomatics; Shao, Y. [Liaoning Technical Univ., Fuxin (China). Dept. of Foreign Language; Guichen, M. [Gifu Univ., Yanagido, Gifu (Japan). Dept. of Civil Engineering


    In China, the surface deformation of ground has been a significant geotechnical problem as a result of cracks in the ground surface, collapsing of house, and subsidence of roads. A powerful technology for detecting surface deformation in the ground is differential interferometry using synthetic aperture radar (INSAR). The technology enables the analysis from different phase of micro-wave between two observed data by synthetic aperture radar (SAR) of surface deformation of ground such as ground subsidence, land slide, and slope failure. In January 2006, the advanced land observing satellite was launched by the Japan Aerospace Exploration Agency. This paper presented an analytical investigation to detect ground subsidence or change caused by mining, overuse of ground water, and disaster. Specifically, the paper discussed the INSAR monitoring technology of the mine slope, including INSAR data sources and processing software; the principle of synthetic aperture radar interferometry; principles of differential SAR interferometry; and INSAR technology to slope monitoring of the Haizhou open pit mine. The paper also discussed the Haizhou strip mine side slope INSAR monitoring results and tests. It was concluded that the use of synthetic aperture radar interferometer technique was the optimal technique to provide three-dimensional spatial information and minimal change from ground surface by spatial remote sensing device. 18 refs., 5 figs.

  6. Slope Stability Assessment of the Sarcheshmeh Landslide, Northeast Iran, Investigated Using InSAR and GPS Observations

    Directory of Open Access Journals (Sweden)

    Mahdi Motagh


    Full Text Available The detection and monitoring of mass movement of susceptible slopes plays a key role in mitigating hazards and potential damage associated with creeping slopes and landslides. In this paper, we use observations from both Interferometric Synthetic Aperture Radar (InSAR and Global Positioning System (GPS to assess the slope stability of the Sarcheshmeh ancient landslide in the North Khorasan province of northeast Iran. InSAR observations were obtained by the time-series analysis of Envisat SAR images covering 2004–2006, whereas repeated GPS observations were conducted by campaign measurements during 2010–2012. Surface displacement maps of the Sarcheshmeh landslide obtained from InSAR and GPS are both indicative of slope stability. Hydrogeological analysis suggests that the multi-year drought and lower than average precipitation levels over the last decade might have contributed to the current dormancy of the Sarcheshmeh landslide.

  7. Error analysis in spaceborne InSAR elevation extraction processing%星载InSAR高程提取过程中的误差分析

    Institute of Scientific and Technical Information of China (English)

    黄长军; 郭际明; 周命端; 袁长征


    DEM的提取是InSAR数据处理中的一项重要的内容,而高程的精度对DEM的提取有着重要影响.本文根据斜距、基线、相位以及高度等量之间的几何构形以及存在的函数关系,推导出了InSAR高程误差公式,分析了影响InSAR测高精度因素的相关性及高程误差;并分别对垂直基线和水平基线对高程精度的影响进行了详细的分析.最后,针对星载InSAR高程提取的特点,提出了一些提高测量精度的参考和建议.%DEM extraction is one of the most important content of InSAR data processing, and the elevation accuracy has an important influence on DEM extraction. This paper analyzed the relevance influence factors of the high precision by InSAR and elevation errors, deduced InSAR elevation error formulas based on the geometric configuration of the slant range, the baseline, the phase and the height. In addition, the impact of elevation accuracy of the vertical baseline and the horizontal baseline are respectively analyzed in detail. At last, aiming at characteristics of effects with Spaceborne InSAR elevation extraction, some schemes and advices are recommended for increasing accuracy in DEM extraction process.

  8. Time Series Analysis of Insar Data: Methods and Trends (United States)

    Osmanoglu, Batuhan; Sunar, Filiz; Wdowinski, Shimon; Cano-Cabral, Enrique


    Time series analysis of InSAR data has emerged as an important tool for monitoring and measuring the displacement of the Earth's surface. Changes in the Earth's surface can result from a wide range of phenomena such as earthquakes, volcanoes, landslides, variations in ground water levels, and changes in wetland water levels. Time series analysis is applied to interferometric phase measurements, which wrap around when the observed motion is larger than one-half of the radar wavelength. Thus, the spatio-temporal ''unwrapping" of phase observations is necessary to obtain physically meaningful results. Several different algorithms have been developed for time series analysis of InSAR data to solve for this ambiguity. These algorithms may employ different models for time series analysis, but they all generate a first-order deformation rate, which can be compared to each other. However, there is no single algorithm that can provide optimal results in all cases. Since time series analyses of InSAR data are used in a variety of applications with different characteristics, each algorithm possesses inherently unique strengths and weaknesses. In this review article, following a brief overview of InSAR technology, we discuss several algorithms developed for time series analysis of InSAR data using an example set of results for measuring subsidence rates in Mexico City.

  9. Evidence of rock slope breathing using ground-based InSAR (United States)

    Rouyet, Line; Kristensen, Lene; Derron, Marc-Henri; Michoud, Clément; Blikra, Lars Harald; Jaboyedoff, Michel; Lauknes, Tom Rune


    Ground-Based Interferometric Synthetic Aperture Radar (GB-InSAR) campaigns were performed in summer 2011 and 2012 in the Romsdalen valley (Møre & Romsdal county, western Norway) in order to assess displacements on Mannen/Børa rock slope. Located 1 km northwest, a second GB-InSAR system continuously monitors the large Mannen rockslide. The availability of two GB-InSAR positions creates a wide coverage of the rock slope, including a slight dataset overlap valuable for validation. A phenomenon of rock slope breathing is detected in a remote and hard-to-access area in mid-slope. Millimetric upward displacements are recorded in August 2011. Analysis of 2012 GB-InSAR campaign, combined with the large dataset from the continuous station, shows that the slope is affected by inflation/deflation phenomenon between 5 and 10 mm along the line-of-sight. The pattern is not homogenous in time and inversions of movement have a seasonal recurrence. These seasonal changes are confirmed by satellite InSAR observations and can possibly be caused by hydrogeological variations. In addition, combination of GB-InSAR results, in situ measurements and satellite InSAR analyses contributes to a better overview of movement distribution over the whole area.

  10. Building detection and building parameter retrieval in InSAR phase images (United States)

    Dubois, Clémence; Thiele, Antje; Hinz, Stefan


    The high resolution provided by the current satellite SAR missions makes them an attractive solution for the detailed analysis of urban areas. Especially due to their weather and daylight independency, they can be employed when optical sensors come to their limits. Due to the specific oblique side-looking configuration of such SAR sensors, phenomena such as layover, double bounce and shadow appear at building location, which can be better understood with very high resolution (VHR) SAR data. The detection of those areas, as well as the retrieval of building parameters through a detailed analysis of the extracted structures, is a challenging task. Indeed, depending on the acquisition configuration, on building material and surroundings, those patterns are not always consistent in amplitude SAR images. They can be difficult to recognize and distinguish automatically. Considering InSAR phase images instead of amplitude images is very helpful for this task, as InSAR is more depending on the geometry. Therefore, in this paper, we focus on the detection and extraction of building layover in InSAR phase images. Two complementing detectors are proposed, and their results are combined, in order to provide reliable building hypotheses. Based on the extracted segments, further analysis is conducted. Especially, the number of connected facades is analyzed. Characteristically geometrical shapes are finally fitted for each facade to permit the determination of the final building parameters as length, width, and height. Results of this approach are shown for three different datasets, first in terms of correctness and completeness of the extraction, and second in terms of accuracy of the extracted building parameters. For the considered datasets, the completeness and correctness are of about 70% and 90%, respectively. Eliminating clear outliers, the determined parameters present an accuracy up to 4 m (length), 2 m (height) and 3 ° (orientation). In this article isolated, middle to

  11. Numerical modeling of land subsidence due to groundwater withdrawal in Aguascalientes Valley using regional coefficients of deformation determined by InSAR analysis. (United States)

    Pacheco, J.; Cabral, E.; Wdowinski, S.; Hernandez-Marin, M.; Ortíz, J. Á.; Solano Rojas, D. E.; Oliver-Cabrera, T.


    Land subsidence due to groundwater over-exploitation is a deformation process affecting many cities around the world. This type of subsidence develops gradual vertical deformations reaching only a few centimeters per year, but can affect large areas. Consequently, inhabitants of subsiding areas are not aware of the process until others effects are observed, such as ground surface faulting, damage to building, or changes in the natural superficial drain. In order to mitigate and forecast subsidence consequences, it is useful to conduct numerical modeling of the subsidence process. Modeling the subsidence includes the following three basic tasks: a) Delimitation of the shape of the deforming body; b) Determination of the forces that are causing the deformations; and c) Determination of the mechanical properties of the deforming body according with an accepted rheological model. In the case of a land subsidence process, the deforming body is the aquifer system that is being drained. Usually, stratigraphic information from pumping wells, and other geophysical data are used to define the boundaries and shape of the aquifer system. The deformation governing forces, or stresses, can be calculated using the theory of "effective stress". Mechanical properties are usually determined with laboratory testing of samples from shallow strata, because the determination of these properties in samples from the deepest strata is economically or technically unviable. Consequently, the results of the numerical modeling do not necessarily match the observed subsidence evolution and ground faulting. We present in this work numerical simulation results of the land subsiding of the Valley of Aguascalientes, Mexico. Two analyses for the same subsiding area are presented. In the first of them, we used the mechanical properties of only the shallow strata, whereas in the second analysis we used "macroscopic" mechanical properties data determined for the whole aquifer system using InSAR

  12. Plate boundary deformation in North Iceland during 1992–2009 revealed by InSAR time-series analysis and GPS

    KAUST Repository

    Metzger, Sabrina


    In North Iceland, extensional plate motion is accommodated by the Northern Volcanic Zone, a set of en-echelon volcanic systems, and the Tjörnes Fracture Zone, a transform offset in the mid-Atlantic Ridge consisting of two parallel transform lineaments. The southern lineament, the Húsavík–Flatey fault, is a 100 km-long right-lateral strike slip fault that has not ruptured for more than 140 years and poses a significant seismic hazard to Húsavík, a fishing town located by the fault, and to other coastal communities. We present results of InSAR time-series analysis data spanning almost two decades (1992–2009) that show extensional and interseismic deformation within the Northern Volcanic Zone and the on-shore part of the Tjörnes Fracture Zone. The results also exhibit transient inflation at Theistareykir volcano, deflation at Krafla central volcano and a broad uplift north of Krafla. The current plate extension is not uniform across the Northern Volcanic Zone, but concentrated at the western fissures of the Theistareykir volcanic system and the outermost fissures of the Krafla fissure swarm. We combine a back-slip plate boundary model with a set of point pressure sources representing volcanic changes to describe the current extensional plate boundary deformation and update the previous estimations of the locking depth and slip rate of the Húsavík–Flatey fault that were based on GPS data alone. Using different combinations of input data, we find that the Húsavík–Flatey fault has a locking depth of 6–10 km and, with a slip rate of 6–9 mm/yr, is accommodating about a third of the full transform motion. We furthermore show that while the InSAR data provide important constraints on the volcanic deformation within the NVZ, they do not significantly improve the model parameter estimation for the HFF, as the dense GPS network appears to better capture the deformation across the fault.

  13. ARIA: Delivering state-of-the-art InSAR products to end users (United States)

    Agram, P. S.; Owen, S. E.; Hua, H.; Manipon, G.; Sacco, G. F.; Bue, B. D.; Fielding, E. J.; Yun, S. H.; Simons, M.; Webb, F.; Rosen, P. A.; Lundgren, P.; Liu, Z.


    Advanced Rapid Imaging and Analysis (ARIA) Center for Natural Hazards aims to bring state-of-the-art geodetic imaging capabilities to an operational level in support of local, national, and international hazard response communities. ARIA project's first foray into operational generation of InSAR products was with Calimap Project, in collaboration with ASI-CIDOT, using X-band data from the Cosmo-SkyMed constellation. Over the last year, ARIA's processing infrastructure has been significantly upgraded to exploit the free stream of high quality C-band SAR data from ESA's Sentinel-1 mission and related algorithmic improvements to the ISCE software. ARIA's data system can now operationally generate geocoded unwrapped phase and coherence products in GIS-friendly formats from Sentinel-1 TOPS mode data in an automated fashion, and this capability is currently being exercised various study sites across the United States including Hawaii, Central California, Iceland and South America. The ARIA team, building on the experience gained from handling X-band data and C-band data, has also built an automated machine learning-based classifier to label the auto-generated interferograms based on phase unwrapping quality. These high quality "time-series ready" InSAR products generated using state-of-the-art processing algorithms can be accessed by end users using two different mechanisms - 1) a Faceted-search interface that includes browse imagery for quick visualization and 2) an ElasticSearch-based API to enable bulk automated download, post-processing and time-series analysis. In this talk, we will present InSAR results from various global events that ARIA system has responded to. We will also discuss the set of geospatial big data tools including GIS libraries and API tools, that end users will need to familiarize themselves with in order to maximize the utilization of continuous stream of InSAR products from the Sentinel-1 and NISAR missions that the ARIA project will generate.

  14. Stochastic modeling for time series InSAR: with emphasis on atmospheric effects (United States)

    Cao, Yunmeng; Li, Zhiwei; Wei, Jianchao; Hu, Jun; Duan, Meng; Feng, Guangcai


    Despite the many applications of time series interferometric synthetic aperture radar (TS-InSAR) techniques in geophysical problems, error analysis and assessment have been largely overlooked. Tropospheric propagation error is still the dominant error source of InSAR observations. However, the spatiotemporal variation of atmospheric effects is seldom considered in the present standard TS-InSAR techniques, such as persistent scatterer interferometry and small baseline subset interferometry. The failure to consider the stochastic properties of atmospheric effects not only affects the accuracy of the estimators, but also makes it difficult to assess the uncertainty of the final geophysical results. To address this issue, this paper proposes a network-based variance-covariance estimation method to model the spatiotemporal variation of tropospheric signals, and to estimate the temporal variance-covariance matrix of TS-InSAR observations. The constructed stochastic model is then incorporated into the TS-InSAR estimators both for parameters (e.g., deformation velocity, topography residual) estimation and uncertainty assessment. It is an incremental and positive improvement to the traditional weighted least squares methods to solve the multitemporal InSAR time series. The performance of the proposed method is validated by using both simulated and real datasets.

  15. Quantitative Analysis of Effect of Atmospheric Delay Error on InSAR Data Processing%大气延迟误差对InSAR数据处理影响的定量分析

    Institute of Scientific and Technical Information of China (English)

    余景波; 刘国林; 曹振坦; 崔娟; 刘会


    从重复轨道InSAR测量基本原理出发,详细给出了相位测量误差对InSAR测高、双轨法D—InSAR形变测量、三轨法D.InSAR形变测量、四轨法D-InSAR形变测量影响的近似关系式以及大气延迟误差对相位测量影响的近似关系式;以此为基础分别推导出了大气延迟误差对InSAR测高、双轨法D-InSAR形变测量、三轨法D.InSAR形变测量和四轨法D—InSAR形变测量影响的近似关系式,同时以ERS-1星载系统为例进行模拟实验,分析讨论了大气延迟误差对InSAR测高、双轨法D—InSAR形变测量、三轨法D-InSAR形变测量以及四轨法D—InSAR形变测量的影响,从而得出了大气延迟误差对InSAR数据处理影响的结论.%The effect approximate relationship formulas of the phase measurement error on height measurement by InSAR and deformation measurement by two-pass, three-pass and four-pass differential InSAR and the effect formulas of atmospheric delay error on the interferometric phase are put forward respectively, taking simultaneously into account the basic principles of the repeat track InSAR measurements. Then, the effect approximate relationship formulas of the atmospheric delay error on height measurement by InSAR and deformation measurement by two-pass differential InSAR, three-pass differential InSAR, four-pass differential InSAR are deduced respectively based on the above formulas. In the last error on InSAR data processing are place, the useful conclusions of the effect of atmospheric delay drawn by taking ERS-1 satellite system simulation experimentsas an example and by talking over and analyzing the effect of atmospheric delay error on height measurement by InSAR and deformation measurement by two-pass differential InSAR, three-pass differential InSAR and four-pass differential InSAR etc.

  16. On InSAR Ambiguity Resolution For Deformation Monitoring (United States)

    Teunissen, P.


    Integer carrier phase ambiguity resolution is the key to fast and highprecision satellite positioning and navigation. It applies to a great variety of current and future models of GPS, modernized GPS and Galileo. It also applies to stacked radar interferometry for deformation monitoring, see e.g. [Hanssen, et al, 2001]. In this contribution we apply the integer least-squares' principle to the rank defect model of stacked InSAR carrier phase data. We discuss two ways of dealing with the rank defect for ambiguity resolution. One is based on the use of a priori data, the other is based on the use of an interval constraint on the deformation rate.

  17. Moon-Based INSAR Geolocation and Baseline Analysis (United States)

    Liu, Guang; Ren, Yuanzhen; Ye, Hanlin; Guo, Huadong; Ding, Yixing; Ruan, Zhixing; Lv, Mingyang; Dou, Changyong; Chen, Zhaoning


    Earth observation platform is a host, the characteristics of the platform in some extent determines the ability for earth observation. Currently most developing platforms are satellite, in contrast carry out systematic observations with moon based Earth observation platform is still a new concept. The Moon is Earth's only natural satellite and is the only one which human has reached, it will give people different perspectives when observe the earth with sensors from the moon. Moon-based InSAR (SAR Interferometry), one of the important earth observation technology, has all-day, all-weather observation ability, but its uniqueness is still a need for analysis. This article will discuss key issues of geometric positioning and baseline parameters of moon-based InSAR. Based on the ephemeris data, the position, liberation and attitude of earth and moon will be obtained, and the position of the moon-base SAR sensor can be obtained by coordinate transformation from fixed seleno-centric coordinate systems to terrestrial coordinate systems, together with the Distance-Doppler equation, the positioning model will be analyzed; after establish of moon-based InSAR baseline equation, the different baseline error will be analyzed, the influence of the moon-based InSAR baseline to earth observation application will be obtained.

  18. Deformation Detection of Potential Landslide with InSAR Observation (United States)

    Liu, Yuzhou; Liao, Mingsheng; Shi, Xuguo; Zhang, Lu


    Influenced by geological and climate conditions, Guide County has been identified as a landslide prone area. Multi-temporal InSAR technique can implement continuous earth surface deformation detection with long time scale and wide geography coverage. In this research, we employ the SBAS method to survey potential landslide in Guide County. Two anomalous deformation regions have been detected by L-band PALSAR stacks. Preliminary correlation between the time series deformation and triggering factors is analyzed to explore the driving mechanism for landslide movement. As a consequence, L-band SAR has a good application potential in landslide monitoring and the results can be the basis for landslide recognizing and early warning.

  19. InSAR observations of the 2009 Racha earthquake, Georgia (United States)

    Nikolaeva, Elena; Walter, Thomas R.


    Central Georgia is an area strongly affected by earthquake and landslide hazards. On 29 April 1991 a major earthquake (Mw  =  7.0) struck the Racha region in Georgia, followed by aftershocks and significant afterslip. The same region was hit by another major event (Mw  =  6.0) on 7 September 2009. The aim of the study reported here was to utilize interferometric synthetic aperture radar (InSAR) data to improve knowledge about the spatial pattern of deformation due to the 2009 earthquake. There were no actual earthquake observations by InSAR in Georgia. We considered all available SAR data images from different space agencies. However, due to the long wavelength and the frequent acquisitions, only the multi-temporal ALOS L-band SAR data allowed us to produce interferograms spanning the 2009 earthquake. We detected a local uplift around 10 cm (along the line-of-sight propagation) in the interferogram near the earthquake's epicenter, whereas evidence of surface ruptures could not be found in the field along the active thrust fault. We simulated a deformation signal which could be created by the 2009 Racha earthquake on the basis of local seismic records and by using an elastic dislocation model. We compared our modeled fault surface of the September 2009 with the April 1991 Racha earthquake fault surfaces and identify the same fault or a sub-parallel fault of the same system as the origin. The patch that was active in 2009 is just adjacent to the 1991 patch, indicating a possible mainly westward propagation direction, with important implications for future earthquake hazards.

  20. A dense medium electromagnetic scattering model for the InSAR correlation of snow (United States)

    Lei, Yang; Siqueira, Paul; Treuhaft, Robert


    Snow characteristics, such as snow water equivalent (SWE) and snow grain size, are important characteristics for the monitoring of the global hydrological cycle and as indicators of climate change. This paper derives an interferometric synthetic aperture radar (InSAR) scattering model for dense media, such as snow, which takes into account multiple scattering effects through the Quasi-Crystalline Approximation. The result of this derivation is a simplified version of the InSAR correlation model derived for relating the InSAR correlation measurements to the snowpack characteristics of grain size, volume fraction, and layer depth as well as those aspects of the volume-ground interaction that affects the interferometric observation (i.e., the surface topography and the ratio of ground-to-volume scattering). Based on the model, the sensitivity of the InSAR correlation measurements to the snow characteristics is explored by simulation. Through this process, it is shown that Ka-band InSAR phase has a good sensitivity to snow grain size and volume fraction, while for lower frequency signals (Ku-band to L-band), the InSAR correlation magnitude and phase have a sensitivity to snow depth. Since the formulation depends, in part, on the pair distribution function, three functional forms of the pair distribution function are implemented and their effects on InSAR phase measurements compared. The InSAR scattering model described in this paper is intended to be an observational prototype for future Ka-band and L-band InSAR missions, such as NASA's Surface Water and Ocean Topography and NASA-ISRO Synthetic Aperture Radar missions, planned for launch in the 2020-2021 time frame. This formulation also enables further investigation of the InSAR-based snow retrieval approaches.

  1. 基于InSAR技术的DEM提取及误差分析%DEM Extraction and Error Analysis Based on InSAR Technology

    Institute of Scientific and Technical Information of China (English)



    The synthetic aperture radar has the advantages of all-weather and all-time observation for the ground. Combined with the characteristics of high interferometry precision, InSAR technology can extract high precision digital elevation model and monitor the small deformation of the surface. Interferometry transforms its abundant phase information into elevation information. The advantage of accessing SAR image makes the application of extracting DEM by InSAR more wide. It is one of the hot spot of research in recent years. Based on a variety of spaceborne SAR data, this paper uses many SAR interference processing softwares to study DEM extraction and carry out the precision comparison. It firstly expounds the basic principle of synthetic aperture radar and introduces the main work pattern of interferometric measure. And then, it studies the basic processing procedure of InSAR to generate DEM, the processing procedure includs data registration, the generation of interference fringes pattern, elimination of flat-earth effect and smoothing, phase unwrapping, geocoding, DEM generation. ERS-1/2 and ENVISAT data is taken as an example to process by tha application of InSAR module of ERDAS IMAGINE, each step is given the specific instructions.%合成孔径雷达具有全天时全天候的对地实时观测优势,结合干涉测量精度高的特点,InSAR技术能够提取高精度的数字高程模型以及对地表微小形变进行监测。干涉测量利用其丰富的相位信息转化为高程信息,再加上获取SAR图像的优势使得InSAR提取DEM得以广泛应用,是近年来研究的热点之一。本文以多种星载SAR数据为基础,应用多种SAR干涉处理软件进行DEM提取的研究,并进行精度对比。首先阐述了合成孔径雷达的基本原理,并介绍了干涉测量的主要工作方式。然后研究了InSAR生成DEM的基本处理流程,包括数据配准,干涉条纹图的生成,去平地效应

  2. A Network Inversion Filter combining GNSS and InSAR for tectonic slip modeling (United States)

    Bekaert, D. P.; Segall, P.; Wright, T. J.; Hooper, A. J.


    Time-dependent slip modeling can be a powerful tool to improve our understanding of the interaction of earthquake cycle processes such as interseismic, coseismic, postseismic, and aseismic slip. Interferometric Synthetic Aperture Radar (InSAR) observations allow us to model slip at depth with a higher spatial resolution than when using GNSS alone. Typically the temporal resolution of InSAR has been limited. However, the recent generation of SAR satellites including Sentinel-1, COSMO-SkyMED, and RADARSAT-2 permits the use of InSAR for time-dependent slip modeling, at intervals of a few days when combined. The increasing amount of SAR data makes a simultaneous data inversion of all epochs challenging. Here, we expanded the original Network Inversion Filter (Segall and Matthews, 1997) to include InSAR observations of surface displacements in addition to GNSS. In the NIF framework, geodetic observations are limited to those of a given epoch, where a physical model describes the slip evolution over time. The combination of the Kalman forward filtering and backward smoothing allows all geodetic observations to constrain the complete observation period. Combining GNSS and InSAR allows us to model time-dependent slip at an unprecedented spatial resolution. We validate the approach with a simulation of the 2006 Guerrero slow slip event. In our study, we emphasize the importance of including the InSAR covariance information, and demonstrate that InSAR provides an additional constraint on the spatial extent of the slow slip. References: Segall, P., and M. Matthews (1997), Time dependent inversion of geodetic data, J. Geophys. Res., 102 (B10), 22,391 - 22,409, doi:10.1029/97JB01795. Bekaert, D., P. Segall, T.J. Wright, and A. Hooper (2016), A Network Inversion Filter combining GNSS and InSAR for tectonic slip modeling, JGR, doi:10.1002/2015JB012638 (open access).

  3. InSAR大气延迟误差分析%Analysis on InSAR Atmospheric Delay Errors

    Institute of Scientific and Technical Information of China (English)




  4. Potential and limits of InSAR to characterize interseismic deformation independently of GPS data: Application to the southern San Andreas Fault system (United States)

    Chaussard, E.; Johnson, C. W.; Fattahi, H.; Bürgmann, R.


    The evaluation of long-wavelength deformation associated with interseismic strain accumulation traditionally relies on spatially sparse GPS measurements, or on high spatial-resolution InSAR velocity fields aligned to a GPS-based model. In this approach the InSAR contributes only short-wavelength deformation and the two data sets are dependent, thereby challenging the evaluation of the InSAR uncertainties and the justification of atmospheric corrections. Here we present an analysis using 7 years of Envisat InSAR data to characterize interseismic deformation along the southern San Andreas Fault (SAF) and the San Jacinto Fault (SJF) in southern California, where the SAF bifurcates onto the Mission Creek (MCF) and the Banning (BF) fault strands. We outline the processing steps for using InSAR alone to characterize both the short- and long-wavelength deformation, and evaluate the velocity field uncertainties with independent continuous GPS data. InSAR line-of-sight (LOS) and continuous GPS velocities agree within ˜1-2 mm/yr in the study area, suggesting that multiyear InSAR time series can be used to characterize interseismic deformation with a higher spatial resolution than GPS. We investigate with dislocation models the ability of this mean LOS velocity field to constrain fault slip rates and show that a single viewing geometry can help distinguish between different slip-rate scenarios on the SAF and SJF (˜35 km apart) but multiple viewing geometries are needed to differentiate slip on the MCF and BF (<12 km apart). Our results demonstrate that interseismic models of strain accumulation used for seismic hazards assessment would benefit from the consideration of InSAR mean velocity maps.

  5. Deriving Dynamic Subsidence of Coal Mining Areas Using InSAR and Logistic Model

    Directory of Open Access Journals (Sweden)

    Zefa Yang


    Full Text Available The seasonal variation of land cover and the large deformation gradients in coal mining areas often give rise to severe temporal and geometrical decorrelation in interferometric synthetic aperture radar (InSAR interferograms. Consequently, it is common that the available InSAR pairs do not cover the entire time period of SAR acquisitions, i.e., temporal gaps exist in the multi-temporal InSAR observations. In this case, it is very difficult to accurately estimate mining-induced dynamic subsidence using the traditional time-series InSAR techniques. In this investigation, we employ a logistic model which has been widely applied to describe mining-related dynamic subsidence, to bridge the temporal gaps in multi-temporal InSAR observations. More specifically, we first construct a functional relationship between the InSAR observations and the logistic model, and we then develop a method to estimate the model parameters of the logistic model from the InSAR observations with temporal gaps. Having obtained these model parameters, the dynamic subsidence can be estimated with the logistic model. Simulated and real data experiments in the Datong coal mining area, China, were carried out in this study, in order to test the proposed method. The results show that the maximum subsidence in the Datong coal mining area reached about 1.26 m between 1 July 2007 and 28 February 2009, and the accuracy of the estimated dynamic subsidence is about 0.017 m. Compared with the linear and cubic polynomial models of the traditional time-series InSAR techniques, the accuracy of dynamic subsidence derived by the logistic model is increased by about 50.0% and 45.2%, respectively.

  6. An estimation method for InSAR interferometric phase combined with image auto-coregistration

    Institute of Scientific and Technical Information of China (English)

    LI Hai; LI Zhenfang; LIAO Guisheng; BAO Zheng


    In this paper we propose a method to estimate the InSAR interferometric phase of the steep terrain based on the terrain model of local plane by using the joint subspace projection technique proposed in our previous paper. The method takes advantage of the coherence information of neighboring pixel pairs to auto-coregister the SAR images and employs the projection of the joint signal subspace onto the corresponding joint noise subspace to estimate the terrain interferometric phase. The method can auto-coregister the SAR images and reduce the interferometric phase noise simultaneously. Theoretical analysis and computer simulation results show that the method can provide accurate estimate of the interferometric phase (interferogram) of very steep terrain even if the coregistration error reaches one pixel. The effectiveness of the method is verified via simulated data and real data.

  7. InSAR datum connection using GNSS-augmented radar transponders (United States)

    Mahapatra, Pooja; der Marel, Hans van; van Leijen, Freek; Samiei-Esfahany, Sami; Klees, Roland; Hanssen, Ramon


    Deformation estimates from Interferometric Synthetic Aperture Radar (InSAR) are relative: they form a `free' network referred to an arbitrary datum, e.g. by assuming a reference point in the image to be stable. However, some applications require `absolute' InSAR estimates, i.e. expressed in a well-defined terrestrial reference frame, e.g. to compare InSAR results with those of other techniques. We propose a methodology based on collocated InSAR and Global Navigation Satellite System (GNSS) measurements, achieved by rigidly attaching phase-stable millimetre-precision compact active radar transponders to GNSS antennas. We demonstrate this concept through a simulated example and practical case studies in the Netherlands.

  8. A Case Study of Using External DEM in InSAR DEM Generation

    Institute of Scientific and Technical Information of China (English)

    ZHOU Chunxia; GE Linlin; E Dongchen; CHANG Hsingchung


    Synthetic aperture radar interferometry (InSAR) has been used as an innovative technique for digital elevation model (DEM) and topographic map generation. In this paper, external DEMs are used for InSAR DEM generation to reduce the errors in data processing. The DEMs generated from repeat-pass InSAR are compared. For steep slopes and severe changes in topography, phase unwrapping quality can be improved by subtracting the phase calculated from an external DEM. It is affirmative that the absolute height accuracy of the InSAR DEM is improved by using external DEM. The data processing was undertaken without the use of ground control points and other manual operation.

  9. Tropical-Forest Profiles and Biomass from TanDEM-X, Single-Baseline Interferometric SAR: InSAR Performance at Higher Frequencies and Bandwidths (United States)

    Treuhaft, R. N.; Goncalves, F. G.; Neumann, M.; Keller, M. M.; Santos, J. R.


    The principal method for remotely sensing forest biomass, particularly high-biomass tropical forests, is to measure vertical structural properties of the forest and relate them to biomass. Interferometric SAR (InSAR) and lidar are the two principal technologies applied to this task. InSAR profile information is constrained in the traditional, look-averaged analysis, because it measures the vertical Fourier transform of the radar power at one and only one vertical frequency specified by the baseline. Lidar produces a full profile, including all Fourier frequencies—all vertical scales of fluctuation. In TanDEM-X data over tropical forests at the Tapajos National Forest, Brazil, we show the results of potentially improving InSAR's Fourier coverage. This is done by estimating many Fourier frequencies with a single baseline, based on the assumption that sampling of the phase height of small (~1.5 m x 2.5 m) looks of TanDEM-X is equivalent to sampling the vertical structure of the forest; a spatial ergodicity. We show a similarity between the distribution of InSAR look-phase-heights (LPH) and lidar and field profiles over 0.25-ha areas. Using Fourier transforms of the histogram of LPH over 0.25 ha areas, biomass estimation improved by about 17% over using InSAR coherence and mean forest height, making it competitive with some lidar results. The RMS of biomasses estimated about field biomass was 48 Mg/ha, with biomasses as high as 430 Mg/ha, and an average of 174 Mg/ha. Perhaps LPH distributions bear a similarity to lidar and field profiles because shorter wavelengths (~3 cm) can penetrate holes in the canopy to scatter off a sample of the vegetation with each look. This "hole mechanism" favors higher frequencies, which are able to penetrate smaller holes. Because they increase the number of look samples, higher bandwidths are also preferred.

  10. Simplex GPS and InSAR Inversion Software (United States)

    Donnellan, Andrea; Parker, Jay W.; Lyzenga, Gregory A.; Pierce, Marlon E.


    Changes in the shape of the Earth's surface can be routinely measured with precisions better than centimeters. Processes below the surface often drive these changes and as a result, investigators require models with inversion methods to characterize the sources. Simplex inverts any combination of GPS (global positioning system), UAVSAR (uninhabited aerial vehicle synthetic aperture radar), and InSAR (interferometric synthetic aperture radar) data simultaneously for elastic response from fault and fluid motions. It can be used to solve for multiple faults and parameters, all of which can be specified or allowed to vary. The software can be used to study long-term tectonic motions and the faults responsible for those motions, or can be used to invert for co-seismic slip from earthquakes. Solutions involving estimation of fault motion and changes in fluid reservoirs such as magma or water are possible. Any arbitrary number of faults or parameters can be considered. Simplex specifically solves for any of location, geometry, fault slip, and expansion/contraction of a single or multiple faults. It inverts GPS and InSAR data for elastic dislocations in a half-space. Slip parameters include strike slip, dip slip, and tensile dislocations. It includes a map interface for both setting up the models and viewing the results. Results, including faults, and observed, computed, and residual displacements, are output in text format, a map interface, and can be exported to KML. The software interfaces with the QuakeTables database allowing a user to select existing fault parameters or data. Simplex can be accessed through the QuakeSim portal graphical user interface or run from a UNIX command line.

  11. A Network Inversion Filter combining GNSS and InSAR for tectonic slip modeling


    Bekaert, D.; P. Segall; Wright, TJ; Hooper, A.


    Studies of the earthquake cycle benefit from long-term time-dependent slip modeling, as it can be a powerful means to improve our understanding on the interaction of earthquake cycle processes such as interseismic, coseismic, postseismic, and aseismic slip. Observations from Interferometric Synthetic Aperture Radar (InSAR) allow us to model slip at depth with a higher spatial resolution than when using GNSS alone. While the temporal resolution of InSAR has typically been limited, the recent f...

  12. Study on interferometric combination for multi-temporal InSAR optimization (United States)

    Wang, Xu; Wang, Yanbing; Li, Xiaojuan; Chen, Yahui; Chen, Xin; Hong, Wei


    Differential synthetic aperture radar interferometry (InSAR) has already proven its potential for ground subsidence monitoring. In recent years Multi-Temporal InSAR technology has been rapid development. Coherence of interferogram is an important indicator to measure the interferometric phase in the Multi-Temporal InSAR system. This paper study the effect of the Spatial-Temporal baseline on coherence for SAR images in Multi-Temporal InSAR processing base on the aspect of statistics. on the basis of a large amount of data, a formula for calculating coherence for SAR images was deduced which it correspond to the relationship between Spatial-Temporal baseline and the coherence of interferogram. This formula can optimize the selection of interference image pairs during processing Multi-Temporal InSAR. To determine whether this formula is useful, two methods of interference image pairs selection was used, one is the formula to optimize the selection, another is the traditional fixed threshold method. The author compared the coherence of Interferogram to judge the merits of the two methods. The results indicate that the formula not only select more interferogram from interferogram stack, but also increase the number of highly coherent points. And use SBAS-InSAR technique to obtain the 2010-2013 Beijing urban land subsidence information, verification monitoring accuracy by comparing level monitoring result.

  13. Deployment and design of bi-directional corner reflectors for op-timal ground motion monitoring using InSAR

    NARCIS (Netherlands)

    Caro Cuenca, M.; Dheenathayalan, P.; Rossum, W.L. van; Hoogeboom, P.


    SAR interferometry (InSAR) requires coherent radar reflections to measure ground displacements. Howev-er, natural coherent reflectors are not always available due to changes in the scattering properties of the ground, e.g., growing vegetation. Furthermore, the opportunistic nature of InSAR measureme

  14. A Network Inversion Filter combining GNSS and InSAR for tectonic slip modeling (United States)

    Bekaert, D. P. S.; Segall, P.; Wright, T. J.; Hooper, A. J.


    Studies of the earthquake cycle benefit from long-term time-dependent slip modeling, as it can be a powerful means to improve our understanding on the interaction of earthquake cycle processes such as interseismic, coseismic, post seismic, and aseismic slip. Observations from Interferometric Synthetic Aperture Radar (InSAR) allow us to model slip at depth with a higher spatial resolution than when using Global Navigation Satellite Systems (GNSS) alone. While the temporal resolution of InSAR has typically been limited, the recent fleet of SAR satellites including Sentinel-1, COSMO-SkyMED, and RADARSAT-2 permits the use of InSAR for time-dependent slip modeling at intervals of a few days when combined. With the vast amount of SAR data available, simultaneous data inversion of all epochs becomes challenging. Here we expanded the original network inversion filter to include InSAR observations of surface displacements in addition to GNSS. In the Network Inversion Filter (NIF) framework, geodetic observations are limited to those of a given epoch, with a stochastic model describing slip evolution over time. The combination of the Kalman forward filtering and backward smoothing allows all geodetic observations to constrain the complete observation period. Combining GNSS and InSAR allows modeling of time-dependent slip at unprecedented spatial resolution. We validate the approach with a simulation of the 2006 Guerrero slow slip event. We highlight the importance of including InSAR covariance information and demonstrate that InSAR provides an additional constraint on the spatial extent of the slow slip.

  15. Methods of InSAR atmosphere correction for volcano activity monitoring (United States)

    Gong, W.; Meyer, F.; Webley, P.W.; Lu, Zhiming


    When a Synthetic Aperture Radar (SAR) signal propagates through the atmosphere on its path to and from the sensor, it is inevitably affected by atmospheric effects. In particular, the applicability and accuracy of Interferometric SAR (InSAR) techniques for volcano monitoring is limited by atmospheric path delays. Therefore, atmospheric correction of interferograms is required to improve the performance of InSAR for detecting volcanic activity, especially in order to advance its ability to detect subtle pre-eruptive changes in deformation dynamics. In this paper, we focus on InSAR tropospheric mitigation methods and their performance in volcano deformation monitoring. Our study areas include Okmok volcano and Unimak Island located in the eastern Aleutians, AK. We explore two methods to mitigate atmospheric artifacts, namely the numerical weather model simulation and the atmospheric filtering using Persistent Scatterer processing. We investigate the capability of the proposed methods, and investigate their limitations and advantages when applied to determine volcanic processes. ?? 2011 IEEE.




    The SAR Interferometry (InSAR) application has shown great potential in monitoring of land terrain changes and in detection of land deformations such as subsidence. Longer time analysis can lead to understand longer trends and changes. Using different bands of SAR satellite (C- from ERS 1-2 and Envisat, L- from ALOS) over the study area, we achieve knowledge of movements in long-term and evaluation of its dynamic changes within observed period of time. Results from InSAR processing fit with t...

  17. Possible Time Dependent Deformation over Socorro Magma Body from GPS and InSAR (United States)

    Havazli, E.; Wdowinski, S.; Amelug, F.


    The Socorro Magma Body (SMB) is one of the largest, currently active magma intrusions in the Earth's continental crust. The area of Socorro is a segment of the Rio Grande Rift that display a broad seismic anomaly and ground deformation. The seismic reflector is imaged at 19 km depth coinciding with the occurrence of numerous small earthquake swarms. Broad crustal uplift was also observed above this reflector and led to the hypothesis of the presence of a large mid-crustal sill-like magma body. Previous geodetic studies over the area reveal ground deformation at the rate of 2-3 mm/yr from 1992 to 2006. The magma body was modeled as a penny-shaped crack of 21 km radius at 19 km depth based on InSAR results [Finnegan et. al., 2009]. In this study we expand the uplift measurement period over the SMB to two decades by using additional InSAR and GPS observations. We extended the InSAR observation record by analyzing 27 Envisat scenes acquired during the years 2006-2010. Continuous GPS observation acquired by the SC01 station since 2001 and three more recent Plate Boundary Observatory stations, which were installed between 2005 and 2011, provide high temporal record of uplift over the past decade and a half. We analyzed the InSAR data using ROI_PAC software package and calculated the temporal evolution of the vertical displacement using time series analysis. Preliminary results of 2006-2010 Envisat data show no significant deformation above the 1-2 mm noise level, which disagree with the previous ERS-1/2 results; 2-3 mm/yr during 1992-2006. This disagreement suggests a time dependent uplift of the SMB, which is also supported by GPS observations. The average uplift rate of the SC01 station is 0.9±0.02 mm/yr for 2001-2015 and 0.6±0.08 mm/yr for 2006-2010. Furthermore the SC01 time series exhibits episodic uplift events. The observed time dependent uplift suggests that magma supply in the middle crust may also occur episodically, as in shallow magmatic systems.

  18. Helmand river hydrologic studies using ALOS PALSAR InSAR and ENVISAT altimetry (United States)

    Lu, Zhiming; Kim, J.-W.; Lee, H.; Shum, C.K.; Duan, J.; Ibaraki, M.; Akyilmaz, O.; Read, C.-H.


    The Helmand River wetland represents the only fresh-water resource in southern Afghanistan and one of the least mapped water basins in the world. The relatively narrow wetland consists of mostly marshes surrounded by dry lands. In this study, we demonstrate the use of the Advanced Land Observing Satellite (ALOS) Phased Array type L-band Synthetic Aperture Radar (PALSAR) Interferometric SAR (InSAR) to detect the changes of the Helmand River wetland water level. InSAR images are combined with the geocentric water level measurements from the retracked high-rate (18-Hz) Environmental Satellite (Envisat) radar altimetry to construct absolute water level changes over the marshes. It is demonstrated that the integration of the altimeter and InSAR can provide spatio-temporal measurements of water level variation over the Helmand River marshes where in situ measurements are absent. ?? Taylor & Francis Group, LLC.

  19. Improvement of the Accuracy of InSAR Image Co-Registration Based On Tie Points – A Review

    Directory of Open Access Journals (Sweden)

    Xiaoli Ding


    Full Text Available Interferometric Synthetic Aperture Radar (InSAR is a new measurement technology, making use of the phase information contained in the Synthetic Aperture Radar (SAR images. InSAR has been recognized as a potential tool for the generation of digital elevation models (DEMs and the measurement of ground surface deformations. However, many critical factors affect the quality of InSAR data and limit its applications. One of the factors is InSAR data processing, which consists of image co-registration, interferogram generation, phase unwrapping and geocoding. The co-registration of InSAR images is the first step and dramatically influences the accuracy of InSAR products. In this paper, the principle and processing procedures of InSAR techniques are reviewed. One of important factors, tie points, to be considered in the improvement of the accuracy of InSAR image co-registration are emphatically reviewed, such as interval of tie points, extraction of feature points, window size for tie point matching and the measurement for the quality of an interferogram.

  20. Monitoring delta subsidence with Interferometric Synthetic Aperture Radar (InSAR) (United States)

    Higgins, S.; Overeem, I.; Syvitski, J. P.


    Can subsidence in river deltas be monitored in near real-time at the spatial and temporal resolution needed for informing critical management decisions? Interferometric Synthetic Radar Aperture (InSAR) is a satellite-based technique that can map ground deformation with millimeter-scale vertical resolution over thousands of square kilometers. InSAR has enormous potential to shed light on the dynamics of actively subsiding deltas, but the technique is not commonly applied outside of major cities due to the difficulty of performing InSAR in wet, vegetated settings. Given these limitations, how can InSAR best serve the global effort to monitor sinking deltas? Here, an overview of InSAR processing is provided that addresses delta-specific challenges, including frequent cloud-cover in tropical areas; noisy signals in wetlands and flooded fields; dense forests that interact unpredictably with different radar wavelengths; flat landscapes that hinder image stacking algorithms; rapid urban development that can render Digital Elevation Models (DEMs) inaccurate; and a lack of in situ GPS (Global Positioning System) receivers for InSAR calibration. InSAR has unique value for monitoring subsidence in deltas, and some natural and anthropogenic drivers of subsidence can be resolved by InSAR. High-resolution InSAR measurements from the Ganges-Brahmaputra Delta (GBD) are then presented and validated against GPS data. Surface motion is shown to reflect subsurface stratigraphy, and sediment compaction is shown to be the most important factor in this delta on short (non-tectonic) timescales. Average compaction rates throughout the eastern delta range from 0 to > 18 mm/y, varying by more than an order of magnitude depending on the ages and grain sizes of surface and subsurface sediment layers. Fastest subsidence is observed in Holocene organic-rich mud, and slowest subsidence is observed along the Meghna River and in areas with surface or subsurface sand deposits. Although groundwater

  1. Examination of InSAR tropospheric delay correction with JRA-55 reanalysis data (United States)

    Kinoshita, Y.; Furuya, M.


    Interferometric Synthetic Aperture Radar (InSAR) phase signal contains not only surface deformations but also propagation delays due to Earth's atmosphere, which is the principal limiting factor for InSAR application of small deformation with amplitude of a few centimeters or less. Bevis et al. (1992) showed that the tropospheric delay consists of the hydrostatic delay due to dry gases and the wet delay due to water vapor. Previous studies proposed correction methods which used GNSS delay data or numerical weather model outputs. However, it is still insignificant for detecting small surface deformation. Jolivet et al. (2014) showed that reanalysis data like ECMWF Interim Re-Analysis (ERA-Interim) data is useful to mitigate topography-correlated tropospheric delay from InSAR data. However, previous studies used only one of the model data as a case study and didn't apply the correction to other areas. In this study we examined an effect of the tropospheric delay correction with Japanese 55-year reanalysis (JRA-55) data (Kobayashi et al., 2015). The horizontal resolution of JRA-55 is TL319 (approximately 60 km) and has 60 vertical layers. In addition, we estimated the tropospheric delay with ERA-Interim data for comparison. SAR data used were derived from ALOS/PALSAR around Nagoya prefecture (Path-Frame: 411-690). To avoid the spatial decorrelation, interferometric pairs with the perpendicular baseline of less 3000 m were generated. As a result, 309 interferograms were generated from 28 SAR single-look complex images. In consequence of the tropospheric delay correction with JRA-55 and ERA-Interim data, the averaged standard deviation of all interferograms slightly reduced from 1.26716 cm to 1.25231 cm by JRA-55 and slightly increased to 1.26797 cm by ERA-Interim. We further examined the correction effect when dividing the estimated delay into the hydrostatic component and the wet component. These results showed that JRA-55 corrected these delays rather than ERA

  2. Mapping inflation at Santorini volcano, Greece, using GPS and InSAR (United States)

    Papoutsis, I.; Papanikolaou, X.; Floyd, M.; Ji, K. H.; Kontoes, C.; Paradissis, D.; Zacharis, V.


    Recent studies have indicated that for the first time since 1950, intense geophysical activity is occurring at the Santorini volcano. Here, we present and discuss the surface deformation associated with this activity, spanning from January 2011 to February 2012. Analysis of satellite interferometry data was performed using two well-established techniques, namely, Persistent Scatterer Interferometry (PSI) and Small Baseline Subset (SBAS), producing dense line-of-sight (LOS) ground deformation maps. The displacement field was compared with GPS observations from 10 continuous sites installed on Santorini. Results show a clear and large inflation signal, up to 150 mm/yr in the LOS direction, with a radial pattern outward from the center of the caldera. We model the deformation inferred from GPS and InSAR using a Mogi source located north of the Nea Kameni island, at a depth between 3.3 km and 6.3 km and with a volume change rate in the range of 12 million m3 to 24 million m3 per year. The latest InSAR and GPS data suggest that the intense geophysical activity has started to diminish since the end of February 2012.

  3. Ground surface deformation patterns, magma supply, and magma storage at Okmok volcano, Alaska, from InSAR analysis: 2. Coeruptive deflation, July-August 2008 (United States)

    Lu, Zhong; Dzurisin, Daniel


    A hydrovolcanic eruption near Cone D on the floor of Okmok caldera, Alaska, began on 12 July 2008 and continued until late August 2008. The eruption was preceded by inflation of a magma reservoir located beneath the center of the caldera and ~3 km below sea level (bsl), which began immediately after Okmok's previous eruption in 1997. In this paper we use data from several radar satellites and advanced interferometric synthetic aperture radar (InSAR) techniques to produce a suite of 2008 coeruption deformation maps. Most of the surface deformation that occurred during the eruption is explained by deflation of a Mogi-type source located beneath the center of the caldera and 2–3 km bsl, i.e., essentially the same source that inflated prior to the eruption. During the eruption the reservoir deflated at a rate that decreased exponentially with time with a 1/e time constant of ~13 days. We envision a sponge-like network of interconnected fractures and melt bodies that in aggregate constitute a complex magma storage zone beneath Okmok caldera. The rate at which the reservoir deflates during an eruption may be controlled by the diminishing pressure difference between the reservoir and surface. A similar mechanism might explain the tendency for reservoir inflation to slow as an eruption approaches until the pressure difference between a deep magma production zone and the reservoir is great enough to drive an intrusion or eruption along the caldera ring-fracture system.

  4. Long-term contraction of pyroclastic flow deposits at Augustine Volcano using InSAR (United States)

    McAlpin, D. B.; Meyer, F. J.; Lu, Z.; Beget, J. E.


    Augustine Island is a small, 8x11 km island in South Central Alaska's lower Cook Inlet. It is approximately 280 km southwest of Anchorage, and occupied entirely by its namesake Augustine Volcano. The volcano's nearly symmetrical central cone reaches an altitude of 1260 m, and the surrounding island is composed almost entirely of volcanic deposits. It is the youngest and most frequently active volcano in the lower Cook Inlet, with at least seven known eruptions since the beginning of written records in 1812. Its two most recent eruptions occurred during March-August 1986, and January-March 2006 The 1986 and 2006 Augustine eruptions produced significant pyroclastic flow deposits (PFDs) on the island, both which have been well mapped by previous studies. Subsidence of material deposited by these pyroclastic flows has been measured by InSAR data, and can be attributed to at least four processes: (1) initial, granular settling; (2) thermal contraction; (3) loading of 1986 PFDs from overlying 2006 deposits; and (4) continuing subsidence of 1986 PFDs buried beneath 2006 flows. For this paper, SAR data for PFDs from Augustine Volcano were obtained from 1992 through 2005, from 2006-2007, and from 2007-2011. These time frames provided InSAR data for long-term periods after both 1986 and 2006 eruptions. From time-series analysis of these datasets, deformation rates of 1986 PFDs and 2006 PFDs were determined, and corrections applied where newer deposits were emplaced over old deposits. The combination of data sets analyzed in this study enabled, for the first time, an analysis of long and short term subsidence rates of volcanic deposits emplaced by the two eruptive episodes. The generated deformation time series provides insight into the significance and duration of the initial settling period and allows us to study the thermal regime and heat loss of the PFDs. To extract quantitative information about thermal properties and composition of the PFDs, we measured the thickness

  5. InSAR detection of permafrost landform dynamics at Kapp Linné central Svalbard (United States)

    Rune Lauknes, Tom; Christiansen, Hanne; Eckerstorfer, Markus; Larsen, Yngvar


    Permafrost is one of six cryospheric indicators of global climate change. As permafrost contains various forms of ground ice, thawing, degradation and speed up of particularly ice-rich periglacial landforms can lead to substantial landscape change and development. This has geomorphological, biological and socio-economical impacts, with changes in the water balance, increase in greenhouse gas emissivity, changes in flora and fauna and impacts on infrastructure. The present scientific challenge is to combine detailed site/point scale geomorphological field process observations with remote sensing data covering at landscape scale. We apply a multi-temporal satellite radar interferometric (InSAR) method to data obtained using the TerraSAR-X satellite. TerraSAR-X has a high spatial resolution and with 11 days repeat cycle, it is well suited to detect seasonal permafrost deformation. To test the usability of X-band InSAR data, we compare hourly field measurements between 2008-2011 of solifluction ground deformation at Kapp Linné, central Svalbard, with InSAR deformation time-series. We show that InSAR is able to pick up the seasonal deformation patterns of frost heave, ground settlement and associated solifluction as well as the interannual downslope movement. These results are a promising first step towards successful upscaling periglacial field point measurements to landscape scale, enabling observations of periglacial processes in larger parts of the permafrost landscapes.

  6. From Ecuador to Patagonia: Andean deformation from InSAR 1992-2007 (United States)

    Pritchard, M. E.; Finnegan, N. J.


    We use Interferometric Synthetic Aperture Radar (InSAR) observations from 6 satellites (ERS-1, ERS-2, ENVISAT, RADARSAT, ALOS, and JERS-1) along with published GPS displacements to constrain the myriad deformational processes in the central and southern Andes between 1992-2007. In this contribution, we review the types of deformation that are occurring (volcanoes, earthquakes, post-seismic and inter-seismic deformation, glaciers, groundwater, and anthropogenic processes) and present new observations and models of these processes. In the central Andes, InSAR observations have been possible in all seasons and have documented numerous sources of deformation: at least 7 volcanic areas, more than a dozen earthquakes (5 oil production in the San Jorge basin, as well as motion of glaciers at the Northern and Southern Patagonian Icefields. Preliminary L-band InSAR data from ALOS indicates great potential for further illuminating deformational processes in the southern Andes.

  7. A Sparsity-Based InSAR Phase Denoising Algorithm Using Nonlocal Wavelet Shrinkage

    Directory of Open Access Journals (Sweden)

    Dongsheng Fang


    Full Text Available An interferometric synthetic aperture radar (InSAR phase denoising algorithm using the local sparsity of wavelet coefficients and nonlocal similarity of grouped blocks was developed. From the Bayesian perspective, the double- l 1 norm regularization model that enforces the local and nonlocal sparsity constraints was used. Taking advantages of coefficients of the nonlocal similarity between group blocks for the wavelet shrinkage, the proposed algorithm effectively filtered the phase noise. Applying the method to simulated and acquired InSAR data, we obtained satisfactory results. In comparison, the algorithm outperformed several widely-used InSAR phase denoising approaches in terms of the number of residues, root-mean-square errors and other edge preservation indexes.

  8. Advanced Interferometric Synthetic Aperture Imaging Radar (InSAR) for Dune Mapping (United States)

    Havivi, Shiran; Amir, Doron; Schvartzman, Ilan; August, Yitzhak; Mamman, Shimrit; Rotman, Stanely R.; Blumberg, Dan G.


    Aeolian morphologies are formed in the presence of sufficient wind energy and available lose particles. These processes occur naturally or are further enhanced or reduced by human intervention. The dimensions of change are dependent primarily on the wind energy and surface properties. Since the 1970s, remote sensing imagery, both optical and radar, have been used for documentation and interpretation of the geomorphologic changes of sand dunes. Remote sensing studies of aeolian morphologies is mostly useful to document major changes, yet, subtle changes, occurring in a period of days or months in scales of centimeters, are very difficult to detect in imagery. Interferometric Synthetic Aperture Radar (InSAR) is an imaging technique for measuring Earth's surface topography and deformation. InSAR images are produced by measuring the radar phase difference between two separated antennas that view the same surface area. Classical InSAR is based on high coherence between two or more images. The output (interferogram) can show subtle changes with an accuracy of several millimeters to centimeters. Very little work has been done on measuring or identifying the changes in dunes using InSAR methods. The reason is that dunes tend to be less coherent than firm, stable, surfaces. This work aims to demonstrate how interferometric decorrelation can be used for identifying dune instability. We hypothesize and demonstrate that the loss of radar coherence over time on dunes can be used as an indication of the dune's instability. When SAR images are acquired at sufficiently close intervals one can measure the time it takes to lose coherence and associate this time with geomorphic stability. To achieve our goals, the coherence change detection method was used, in order to identify dune stability or instability and the dune activity level. The Nitzanim-Ashdod coastal dunes along the Mediterranean, 40 km south of Tel-Aviv, Israel, were chosen as a case study. The dunes in this area are of

  9. The potential of more accurate InSAR covariance matrix estimation for land cover mapping (United States)

    Jiang, Mi; Yong, Bin; Tian, Xin; Malhotra, Rakesh; Hu, Rui; Li, Zhiwei; Yu, Zhongbo; Zhang, Xinxin


    Synthetic aperture radar (SAR) and Interferometric SAR (InSAR) provide both structural and electromagnetic information for the ground surface and therefore have been widely used for land cover classification. However, relatively few studies have developed analyses that investigate SAR datasets over richly textured areas where heterogeneous land covers exist and intermingle over short distances. One of main difficulties is that the shapes of the structures in a SAR image cannot be represented in detail as mixed pixels are likely to occur when conventional InSAR parameter estimation methods are used. To solve this problem and further extend previous research into remote monitoring of urban environments, we address the use of accurate InSAR covariance matrix estimation to improve the accuracy of land cover mapping. The standard and updated methods were tested using the HH-polarization TerraSAR-X dataset and compared with each other using the random forest classifier. A detailed accuracy assessment complied for six types of surfaces shows that the updated method outperforms the standard approach by around 9%, with an overall accuracy of 82.46% over areas with rich texture in Zhuhai, China. This paper demonstrates that the accuracy of land cover mapping can benefit from the 3 enhancement of the quality of the observations in addition to classifiers selection and multi-source data ingratiation reported in previous studies.

  10. 基线特征对天基双天线InSAR性能的影响分析%Influence Analysis of Baseline Characteristics on Space Bi-antenna InSAR Performance

    Institute of Scientific and Technical Information of China (English)

    孙造宇; 董臻


    The platform of space bi-antenna InSAR includes space station, space shuttle, etc. The baseline characteristics of the space bi-antenna InSAR can seriously influence the interferometric performance. Three main factors which can influence the interferometric baseline are analyzed, namely, attitude variety, oscillation and measurement error. Analysis shows that the baseline variety caused by attitude variety and mast oscillation may result in coherence variety and image phase variety, which will consequently affect the interferometric performance. Interferometric phase variety caused by image phase variety is the main factor, and precise baseline measurement is needed for compensation. Theoretic analysis is verified through simulation.%天基双天线InSAR以空间站等为平台,其基线特征对系统干涉测高性能有重要影响。针对姿态变化、振动和基线测量误差三个影响干涉测高性能的主要因素开展分析,可以得出姿态变化和天线杆振动引起的基线变化会造成干涉相干性的变化、图像相位变化等,进而影响干涉测高,图像相位变化引起的干涉相位变化是其中主要影响因素,为了对其进行补偿,需要高精度的基线测量。仿真结果验证了理论上的分析。

  11. The wet refractivity tomography for improving the InSAR deformation measurements on Mt. Etna (United States)

    Spinetti, Claudia; Aranzulla, Massimo; Guglielmino, Francesco; Cannavo', Flavio; Romaniello, Vito; Briole, Pierre; Puglisi, Giuseppe


    and Aqua. When the cloud covers permits the use of this data, its addition provides a double benefit: it improves the tomographic resolution and it adds a feedback for the GPS wet delay measurements. Finally, the tomography algorithm was applied on InSAR Sentinel-1 IW data on Mt. Etna during the 2015 year. In order to reduce the known problem of the correction for the antenna pattern, the interferometric process was performed only on one burst of one subset of Sentinel-1 IW data. We present the results of this analysis of some 2015 test cases.

  12. The InSAR Scientific Computing Environment (ISCE): A Python Framework for Earth Science (United States)

    Rosen, P. A.; Gurrola, E. M.; Agram, P. S.; Sacco, G. F.; Lavalle, M.


    The InSAR Scientific Computing Environment (ISCE, funded by NASA ESTO) provides a modern computing framework for geodetic image processing of InSAR data from a diverse array of radar satellites and aircraft. ISCE is both a modular, flexible, and extensible framework for building software components and applications as well as a toolbox of applications for processing raw or focused InSAR and Polarimetric InSAR data. The ISCE framework contains object-oriented Python components layered to construct Python InSAR components that manage legacy Fortran/C InSAR programs. Components are independently configurable in a layered manner to provide maximum control. Polymorphism is used to define a workflow in terms of abstract facilities for each processing step that are realized by specific components at run-time. This enables a single workflow to work on either raw or focused data from all sensors. ISCE can serve as the core of a production center to process Level-0 radar data to Level-3 products, but is amenable to interactive processing approaches that allow scientists to experiment with data to explore new ways of doing science with InSAR data. The NASA-ISRO SAR (NISAR) Mission will deliver data of unprecedented quantity and quality, making possible global-scale studies in climate research, natural hazards, and Earth's ecosystems. ISCE is planned as the foundational element in processing NISAR data, enabling a new class of analyses that take greater advantage of the long time and large spatial scales of these new data. NISAR will be but one mission in a constellation of radar satellites in the future delivering such data. ISCE currently supports all publicly available strip map mode space-borne SAR data since ERS and is expected to include support for upcoming missions. ISCE has been incorporated into two prototype cloud-based systems that have demonstrated its elasticity in addressing larger data processing problems in a "production" context and its ability to be

  13. 机载InSAR系统成像对DGPS/IMU要求分析%Requirement Analysis of DGPS/IMU for Air-Borne InSAR System's Imaging

    Institute of Scientific and Technical Information of China (English)

    楼良盛; 刘志铭; 周瑜


    The elevation is surveyed by the InSAR system through the phase difference of the two interference complex images, so the phase accuracy is one of the main factors that influences the system's elevation surveying accuracy. According to the principle of the InSAR imaging movement compensation, the position and velocity surveyed by DGPS/IMU will directly influence the accuracy of imaging movement compensation. On the basis of analyzing the influence of InSAR imaging movement compensation to the phase accuracy and phase accuracy to the elevation surveying accuracy, and according to the requirement of the phase accuracy in the InSAR system, the accuracy requirements of the DGPS/IMU in the InSAR imaging movement compensation were proposed.%InSAR系统根据两幅相干复影像的相位差进行高程测量,相位精度是影响系统高程测量精度的主要因素之一.依据InSAR成像运动补偿原理,DGPS/IMU测量的位置和速度精度将直接影响成像运动补偿精度.在分析了InSAR成像运动补偿对相位精度及相位精度对高程测量精度影响的基础上,根据InSAR系统对相位精度的要求,提出了InSAR成像运动补偿对DGPS/IMU精度要求.

  14. Characterizing 6 August 2007 Crandall Canyon mine collapse from ALOS PALSAR InSAR (United States)

    Lu, Zhong; Wicks, Charles


    We used ALOS InSAR images to study land surface deformation over the Crandall Canyon mine in Utah, which collapsed on 6 August 2007 and killed six miners. The collapse was registered as a ML 3.9 seismic event. An InSAR image spanning the time of the collapse shows 25–30 cm surface subsidence over the mine. We used distributed dislocation sources to model the deformation field, and found that a collapse source model alone does not adequately fit the deformation

  15. Forecasting and Managing Groundwater Resources Using InSAR (United States)

    Zebker, H. A.; Knight, R. J.; Chen, J.


    Groundwater management is highly dependent on the type and quality of field data available describing a given aquifer system. Our increasing reliance on groundwater, especially as traditional surface supplies continue to be overexploited due to rising population and standard of living, requires that we better understand the state of our subsurface supplies and how to best manage them. The dense spatial and temporal variability of subsidence provided by time series InSAR allows us to constrain the extent of an aquifer, its storage coefficient, estimates of hydraulic head, and hydraulic conductivity. We present examples of these parameters associated with groundwater systems in the San Luis Valley, CO, and the Central Valley area of California, as observed by several spaceborne radar systems and validated by comparison with field data. Groundwater is one component of a water system, which includes surface supplies and all of the various sources and end uses of water in a particular area. Confined aquifers remain the most difficult components of a full water system to characterize and properly manage, as they lie deep underground and are hidden from direct observation. We show that observing subtle deformations of the surface elevations on the order of mm to cm yield important constraints on the underlying aquifer and its hydraulic properties, because variations in the surface height expresses changes in water pressure below. The fundamental relation between pressure and stress resulting in changes in hydraulic head yields a simple linear relationship between deformation Δb, hydraulic head Δh, and skeletal storage coefficient: Sk = Δb / Δh, so that measuring deformation everywhere above an aquifer over time yields change in head. Using InSAR-observed temporal response of the head (deformation) to changes in forcing by water sources and sinks, and applying the one dimensional diffusion equation resulting from Darcy's Law and the continuity relation allows us to

  16. Generalized interpretation scheme for arbitrary HR InSAR image pairs (United States)

    Boldt, Markus; Thiele, Antje; Schulz, Karsten


    Land cover classification of remote sensing imagery is an important topic of research. For example, different applications require precise and fast information about the land cover of the imaged scenery (e.g., disaster management and change detection). Focusing on high resolution (HR) spaceborne remote sensing imagery, the user has the choice between passive and active sensor systems. Passive systems, such as multispectral sensors, have the disadvantage of being dependent from weather influences (fog, dust, clouds, etc.) and time of day, since they work in the visible part of the electromagnetic spectrum. Here, active systems like Synthetic Aperture Radar (SAR) provide improved capabilities. As an interactive method analyzing HR InSAR image pairs, the CovAmCohTM method was introduced in former studies. CovAmCoh represents the joint analysis of locality (coefficient of variation - Cov), backscatter (amplitude - Am) and temporal stability (coherence - Coh). It delivers information on physical backscatter characteristics of imaged scene objects or structures and provides the opportunity to detect different classes of land cover (e.g., urban, rural, infrastructure and activity areas). As example, railway tracks are easily distinguishable from other infrastructure due to their characteristic bluish coloring caused by the gravel between the sleepers. In consequence, imaged objects or structures have a characteristic appearance in CovAmCoh images which allows the development of classification rules. In this paper, a generalized interpretation scheme for arbitrary InSAR image pairs using the CovAmCoh method is proposed. This scheme bases on analyzing the information content of typical CovAmCoh imagery using the semisupervised k-means clustering. It is shown that eight classes model the main local information content of CovAmCoh images sufficiently and can be used as basis for a classification scheme.

  17. Numerical weather prediction models and SAR interferometry: synergic use for meteorological and INSAR applications (United States)

    Pierdicca, Nazzareno; Rocca, Fabio; Perissin, Daniele; Ferretti, Rossella; Pichelli, Emanuela; Rommen, Bjorn; Cimini, Nico


    Spaceborne Interferometric Synthetic Aperture Radar (InSAR) is a well established technique useful in many land applications, such as landslide monitoring and digital elevation model extraction. One of its major limitation is the atmospheric effect, and in particular the high water vapour spatial and temporal variability which introduces an unknown delay in the signal propagation. However, the sensitivity of SAR interferometric phase to atmospheric conditions could in principle be exploited and InSAR could become in certain conditions a tool to monitor the atmosphere, as it happens with GPS receiver networks. This paper describes a novel attempt to assimilate InSAR derived information on the atmosphere, based on the Permanent Scatterer multipass technique, into a numerical weather forecast model. The methodology is summarised and the very preliminary results regarding the forecast of a precipitation event in Central Italy are analysed. The work was done in the framework of an ESA funded project devoted to the mapping of the water vapour with the aim to mitigate its effect for InSAR applications.

  18. SAR-GMTI investigation in hybrid along-and cross-track baseline InSAR

    Institute of Scientific and Technical Information of China (English)

    SUO ZhiYong; LI ZhenFang; BAO Zheng; WU JianXin


    A joint-pixel clutter suppression method based on slope compensation is proposed in this paper. In order to eliminate the effect of the terrain interferometric phase caused by the cross-track baseline in hybrid baseline InSAR, the local independent identical distribution of the clutter is satisfied by using the slope compensation technique, and thus the clutter can be suppressed successfully by using the orthogonality of the clutter subspace and the noise subspace. This approach utilizes the information contained in the current pixel as well as in its neighbors, showing robustness to the image coregistration errors. Both the simulated data and the real airborne data are used in proving the validity of the presented approach.

  19. Cascades of InSAR in the Cascades - outlook for the use of InSAR and space-based imaging catalogues in a Subduction Zone Observatory (United States)

    Lohman, R. B.


    Interferometric synthetic aperture radar (InSAR) has long demonstrated its utility to studies of subduction zone earthquakes, crustal events and volcanic processes, particularly in regions with very good temporal data coverage (e.g., Japan), or arid regions where the timescale of surface change is long compared to the repeat time of the available SAR imagery (e.g., portions of South America). Recently launched and future SAR missions with open data access will increase the temporal sampling rates further over many areas of the globe, resulting in a new ability to lower the detection threshold for earthquakes and, potentially, interseismic motion and transients associated with subduction zone settings. Here we describe some of the anticipated detection abilities for events ranging from earthquakes and slow slip along the subduction zone interface up to landslides, and examine the variations in land use around the circum-Pacific and how that and its changes over time will affect the use of InSAR. We will show the results of an effort to combine Landsat and other optical imagery with SAR data catalogues in the Pacific Northwest to improve the characterization of ground deformation signals, including the identification of "spurious" signals that are not related to true ground deformation. We also describe prospects for working with other communities that are interested in variations in soil moisture and vegetation structure over the same terrain.

  20. Tropical Forest Biomass Estimation from Vertical Fourier Transforms of Lidar and InSAR Profiles (United States)

    Treuhaft, R. N.; Goncalves, F.; Drake, J.; Hensley, S.; Chapman, B. D.; Michel, T.; Dos Santos, J. R.; Dutra, L.; Graca, P. A.


    Structural forest biomass estimation from lidar or interferometric SAR (InSAR) has demonstrated better performance than radar-power-based approaches for the higher biomasses (>150 Mg/ha) found in tropical forests. Structural biomass estimation frequently regresses field biomass to some function of forest height. With airborne, 25-m footprint lidar data and fixed-baseline C-band InSAR data over tropical wet forests of La Selva Biological Station, Costa Rica, we compare the use of Fourier transforms of vertical profiles at a few frequencies to the intrinsically low-frequency “average height”. RMS scatters of Fourier-estimated biomass about field-measured biomass improved by 40% and 20% over estimates base on average height from lidar and fixed-baseline InSAR, respectively. Vertical wavelengths between 14 and 100 m were found to best estimate biomass. The same airborne data acquisition over La Selva was used to generate many 10’s of repeat-track L-band InSAR baselines with time delays of 1-72 hours, and vertical wavelengths of 5-100 m. We will estimate biomass from the Fourier transforms of L-band radar power profiles (InSAR complex coherence). The effects of temporal decorrelation will be modeled in the Fourier domain to try to model and reduce their impact. Using L-band polarimetric interferometry, average heights will be estimated as well and biomass regression performance compared to the Fourier transform approach. The more traditional approach of using L-band radar polarimetry will also be compared to structural biomass estimation.

  1. Geodetic network design for InSAR: Application to ground deformation monitoring

    NARCIS (Netherlands)

    Mahapatra, P.S.


    For the past two decades, interferometric synthetic aperture radar (InSAR) has been used to monitor ground deformation with subcentimetric precision from space. But the applicability of this technique is limited in regions with a low density of naturally-occurring phase-coherent radar targets, e.g.

  2. Statistical description of tropospheric delay for InSAR : Overview and a new model

    DEFF Research Database (Denmark)

    Merryman Boncori, John Peter; Mohr, Johan Jacob


    This paper focuses on statistical modeling of water vapor fluctuations for InSAR. The structure function and power spectral density approaches are reviewed, summarizing their assumptions and results. The linking equations between these modeling techniques are reported. A structure function model...

  3. Monitoring Structural Health of Different Types of Bridges Using Advanced Multi-Temporal InSAR (United States)

    Qin, Xiaoqiong; Liao, Mingsheng; Yang, Mengshi; Zhang, Lu; Balz, Timo


    Since the bridges paly a significance role in national economic development and transportation safety, the structure health and safety of bridges aroused a lot of concern in society and become a hotspot research in earth observation and civil engineering. However, the materials degradation and environmental stresses increase may destroy the structure of bridges and pose significant risks to public safety and quality of life. This highlighted the importance of developing effective structure health monitoring strategies to reflect the current status of bridges and identify structural problems. In this work, an advanced multi-temporal InSAR technique is introduced into deformation monitoring of bridges. We focus on analysis the distribution of PSs, distinction of stable and unstable parts and recognition temporal-spatial deformation characteristics at the scale of single bridge through the examples of different types of bridges in Tianjin and Shanghai.

  4. InSAR Tropospheric Correction Methods: A Statistical Comparison over Different Regions (United States)

    Bekaert, D. P.; Walters, R. J.; Wright, T. J.; Hooper, A. J.; Parker, D. J.


    Observing small magnitude surface displacements through InSAR is highly challenging, and requires advanced correction techniques to reduce noise. In fact, one of the largest obstacles facing the InSAR community is related to tropospheric noise correction. Spatial and temporal variations in temperature, pressure, and relative humidity result in a spatially-variable InSAR tropospheric signal, which masks smaller surface displacements due to tectonic or volcanic deformation. Correction methods applied today include those relying on weather model data, GNSS and/or spectrometer data. Unfortunately, these methods are often limited by the spatial and temporal resolution of the auxiliary data. Alternatively a correction can be estimated from the high-resolution interferometric phase by assuming a linear or a power-law relationship between the phase and topography. For these methods, the challenge lies in separating deformation from tropospheric signals. We will present results of a statistical comparison of the state-of-the-art tropospheric corrections estimated from spectrometer products (MERIS and MODIS), a low and high spatial-resolution weather model (ERA-I and WRF), and both the conventional linear and power-law empirical methods. We evaluate the correction capability over Southern Mexico, Italy, and El Hierro, and investigate the impact of increasing cloud cover on the accuracy of the tropospheric delay estimation. We find that each method has its strengths and weaknesses, and suggest that further developments should aim to combine different correction methods. All the presented methods are included into our new open source software package called TRAIN - Toolbox for Reducing Atmospheric InSAR Noise (Bekaert et al., in review), which is available to the community Bekaert, D., R. Walters, T. Wright, A. Hooper, and D. Parker (in review), Statistical comparison of InSAR tropospheric correction techniques, Remote Sensing of Environment

  5. Advanced corrections for InSAR using GPS and numerical weather models (United States)

    Foster, J. H.; Cossu, F.; Amelung, F.; Businger, S.; Cherubini, T.


    The complex spatial and temporal changes in the atmospheric propagation delay of the radar signal remain the single biggest factor limiting Interferometric Synthetic Aperture Radar's (InSAR) potential for hazard monitoring and mitigation. A new generation of InSAR systems is being built and launched, and optimizing the science and hazard applications of these systems requires advanced methodologies to mitigate tropospheric noise. We present preliminary results from an investigation into the application of GPS and numerical weather models for generating tropospheric correction fields. We use the Weather Research and Forecasting (WRF) model to generate a 900 m spatial resolution atmospheric model covering the Big Island of Hawaii and an even higher, 300 m resolution grid over Mauna Loa and Kilauea volcanoes. By comparing a range of approaches, from the simplest, using reanalyses based on typically available meteorological observations, through to the "kitchen-sink" approach of assimilating all relevant data sets into our custom analyses, we examine the impact of the additional data sets on the atmospheric models and their effectiveness in correcting InSAR data. We focus particularly on the assimilation of information from the more than 60 GPS sites in the island. We ingest zenith tropospheric delay estimates from these sites directly into the WRF analyses, and also perform double-difference tomography using the phase residuals from the GPS processing to robustly incorporate information on atmospheric heterogeneity from the GPS data into the models. We assess our performance through comparisons of our atmospheric models with external observations not ingested into the model, and through the effectiveness of the derived phase screens in reducing InSAR variance. This work will produce best-practice recommendations for the use of weather models for InSAR correction, and inform efforts to design a global strategy for the NISAR mission, for both low-latency and definitive

  6. InSAR Used for Subsidence Monitoring of Mining Area OKR, Czech Republic (United States)

    Lazecky, Milan


    The abilities of InSAR processing techniques to detect and monitor subsidence of mining areas were already proved in several works, e.g. of Dr. Perski that used them in Poland. As an ESA project of VSB-TU Ostrava using data from ERS 1,2 and Envisat ASAR, the InSAR has been applied also for the Northern Moravian OKR region in Czech Republic, a region with a long black coal mining history. Mining activities in this area have caused damages and destructions of many buildings, tramlines etc. The problem is still actual, even that only 4 mines are active, since 2007. Via the InSAR processing, an evolution of subsidence during last 10 years is monitored using the Doris software. Due to highly decorrelated interferograms created from newer data (since 2001), the actual state is hardly interpretable though. The critical subsiding objects were detected by pointwise multitemporal InSAR techniques (MT- InSAR) - the permanent scatterers and small baselines methods using the StaMPS software. The results were compared with the in-situ levelling revealing that the estimated rate of subsidence was underestimated. Only the ERS-2 data from period 1999-2000 were successfully used in these advanced InSAR techniques to achieve some reasonable results. Because of gyroscopes failure of ERS-2, the data since January 2001 couldn't be processed successfully by StaMPS due to big differences in the Doppler centroid frequencies of each images - an abortive result of a small baselines method attempt can be presented. Because of used long- wall mining method, that evokes spatial movement of subsidence epicenters in time, a longer time period of dataset usable in MT-InSAR would decrease the processing merit (the character of subsidence in the area is not pointwise in longer time period). This project will continue with a processing of newer datasets to achieve a complete overview of terrain changes in the mining area during the last decade.

  7. Application of InSAR and gravimetric surveys for developing construction codes in zones of land subsidence induced by groundwater extraction: case study of Aguascalientes, Mexico (United States)

    Pacheco-Martínez, J.; Wdowinski, S.; Cabral-Cano, E.; Hernández-Marín, M.; Ortiz-Lozano, J. A.; Oliver-Cabrera, T.; Solano-Rojas, D.; Havazli, E.


    Interferometric Synthetic Aperture Radar (InSAR) has become a valuable tool for surface deformation monitoring, including land subsidence associated with groundwater extraction. Another useful tools for studying Earth's surface processes are geophysical methods such as Gravimetry. In this work we present the application of InSAR analysis and gravimetric surveying to generate valuable information for risk management related to land subsidence and surface faulting. Subsidence of the city of Aguascalientes, Mexico is presented as study case. Aguascalientes local governments have addressed land subsidence issues by including new requirements for new constructions projects in the State Urban Construction Code. Nevertheless, the resulting zoning proposed in the code is still subjective and not clearly defined. Our work based on gravimetric and InSAR surveys is aimed for improving the subsidence hazard zoning proposed in the State Urban Code in a more comprehensive way. The study includes a 2007-2011 ALOS InSAR time-series analysis of the Aguascalientes valley, an interpretation of the compete Bouguer gravimetric anomaly of the Aguascalientes urban area, and the application of time series and gravimetric anomaly maps for improve the subsidence hazard zoning of Aguascalientes City.

  8. Advanced InSAR techniques for the management and characterization of geothermal resources (United States)

    Bellotti, F.; Falorni, G.; Morgan, J.; Rucci, A.; Ferretti, A.


    InSAR is a remote sensing tool that has applications in both geothermal exploitation and in the management of producing fields. The technique has developed rapidly in recent years and the most evolved algorithms, now capable of providing precise ground movement measurements with unprecedented spatial density over large areas, allow the monitoring of the effects of fluid injection and extraction on surface deformation and the detection of active faults. Multi-interferogram approaches have been used at several geothermal sites in different stages of development. SqueeSAR™, which represents the latest breakthrough in InSAR technology, provides a significant increase in the spatial density of measurement points by exploiting signal returns from both point-like and distributed scatterers. Furthermore, recent satellite radar sensors have a higher spatial resolution (down to 1 m), as well as a higher temporal frequency of image acquisitions (down to a few days). The coupling of the new algorithm with this new generation of satellites provides a valuable tool for monitoring the different phases of geothermal production and in support of the decision making process. Some examples from the US are presented here: the first case study involves the use of InSAR within a suite of tools for exploration of the San Emidio geothermal field in Nevada. This project aimed to develop geophysical techniques to identify and map large aperture fractures for the placement of new production/exploration wells. The second and third examples examine two zones in California: the Salton Sea area, where multi-interferogram InSAR provided an overview of surface deformation at a producing geothermal reservoir. Surface deformation in this area was complex, and the added detail provided insight into the interplay of tectonics and production activities. Additional InSAR studies have also been carried out at the Geysers field in order to evaluate the behavior of an Enhanced Geothermal System (EGS) in

  9. Assessing Groundwater Depletion and Dynamics Using GRACE and InSAR: Potential and Limitations. (United States)

    Castellazzi, Pascal; Martel, Richard; Galloway, Devin L; Longuevergne, Laurent; Rivera, Alfonso


    In the last decade, remote sensing of the temporal variation of ground level and gravity has improved our understanding of groundwater dynamics and storage. Mass changes are measured by GRACE (Gravity Recovery and Climate Experiment) satellites, whereas ground deformation is measured by processing synthetic aperture radar satellites data using the InSAR (Interferometry of Synthetic Aperture Radar) techniques. Both methods are complementary and offer different sensitivities to aquifer system processes. GRACE is sensitive to mass changes over large spatial scales (more than 100,000 km(2) ). As such, it fails in providing groundwater storage change estimates at local or regional scales relevant to most aquifer systems, and at which most groundwater management schemes are applied. However, InSAR measures ground displacement due to aquifer response to fluid-pressure changes. InSAR applications to groundwater depletion assessments are limited to aquifer systems susceptible to measurable deformation. Furthermore, the inversion of InSAR-derived displacement maps into volume of depleted groundwater storage (both reversible and largely irreversible) is confounded by vertical and horizontal variability of sediment compressibility. During the last decade, both techniques have shown increasing interest in the scientific community to complement available in situ observations where they are insufficient. In this review, we present the theoretical and conceptual bases of each method, and present idealized scenarios to highlight the potential benefits and challenges of combining these techniques to remotely assess groundwater storage changes and other aspects of the dynamics of aquifer systems.

  10. Assessing groundwater depletion and dynamics using GRACE and InSAR: Potential and limitations (United States)

    Castellazzi, Pascal; Martel, Richard; Galloway, Devin L.; Longuevergne, Laurent; Rivera, Alfonso


    In the last decade, remote sensing of the temporal variation of ground level and gravity has improved our understanding of groundwater dynamics and storage. Mass changes are measured by GRACE (Gravity Recovery and Climate Experiment) satellites, whereas ground deformation is measured by processing synthetic aperture radar satellites data using the InSAR (Interferometry of Synthetic Aperture Radar) techniques. Both methods are complementary and offer different sensitivities to aquifer system processes. GRACE is sensitive to mass changes over large spatial scales (more than 100,000 km2). As such, it fails in providing groundwater storage change estimates at local or regional scales relevant to most aquifer systems, and at which most groundwater management schemes are applied. However, InSAR measures ground displacement due to aquifer response to fluid-pressure changes. InSAR applications to groundwater depletion assessments are limited to aquifer systems susceptible to measurable deformation. Furthermore, the inversion of InSAR-derived displacement maps into volume of depleted groundwater storage (both reversible and largely irreversible) is confounded by vertical and horizontal variability of sediment compressibility. During the last decade, both techniques have shown increasing interest in the scientific community to complement available in situ observations where they are insufficient. In this review, we present the theoretical and conceptual bases of each method, and present idealized scenarios to highlight the potential benefits and challenges of combining these techniques to remotely assess groundwater storage changes and other aspects of the dynamics of aquifer systems.

  11. Surface Deformation of Los Humeros Caldera, Mexico, Estimated by Interferometric Synthetic Aperture Radar (InSAR). (United States)

    Santos Basurto, R.; Lopez Quiroz, P.; Carrasco Nuñez, G.; Doin, M. P.


    Los Humeros caldera is located in the eastern part of the Trans-Mexican Volcanic Belt, to the north of the state of Puebla and bordering the west side of the state of Veracruz. The study of the caldera, is of great interest because there is a geothermal field currently working inside of it. In fact, Los Humeros, is the third more important geothermal field in Mexico. In this work, we used InSAR to estimate the surface deformation on the caldera, aiming to contribute to its modeling and to help preventing subsidence related hazards on the geothermal field and surroundings. On this study, we calculated 34 interferograms from 21 SAR images of the ENVISAT European Space Agency Mission. The analysis of the interferograms, allow us to detect, decorrelation of the interferometric signal increased, when time spans were greater than 70 days. Also, for those with good signal correlation, the atmospheric signal dominated the interferogram, masking completely the deformation. Moreover, residual orbital ramps were detected, in some of the calculated interferograms. An algorithm capable to remove all the interferogram signal contributions but the deformation related, has been implemented. Resulting deformation and its correlation with several variables like the geology, the hydrogeology and the seismic records, were analysed through its integration in a Geographic Information System.

  12. Using InSAR for Characterizing Pyroclastic Flow Deposits at Augustine Volcano Across Two Eruptive Cycles (United States)

    McAlpin, D. B.; Meyer, F. J.; Lu, Z.; Beget, J. E.


    Augustine Island is a small, 8x11 km island in South Central Alaska's lower Cook Inlet. It is approximately 280 km southwest of Anchorage, and occupied entirely by its namesake Augustine Volcano. At Augustine Volcano, SAR data suitable for interferometry is available from 1992 to 2005, from March 2006 to April 2007, and from July 2007 to October 2010. Its last two eruptive episodes, in 1986 and 2006, resulted in substantial pyroclastic flow deposits (PFDs) on the Volcano's north flank. Earlier InSAR analyses of the area, from 1992-1999, identified local subsidence, but no volcano-wide deformation indicative of magma-chamber evacuation. In contrast to previous studies, we use InSAR data to determine a range of geophysical parameters for PFDs emplaced during the Augustine's two most recent eruption cycles. Based on InSAR measurements between 1992 and 2010, we reconstruct the deformation behavior of PFDs emplaced during Augustine's last two eruption cycles. Using a combination of InSAR measurements and modeling, we determine the thickness and long-term deformation of overlaying pyroclastic flow deposits emplaced in 1986 and 2006. Consistent with previous observations of pyroclastic flows, we found that the PFDs on Augustine Island rapidly subsided after emplacement due to an initial compaction of the material. We determined the length of this initial settling period and measured the compaction rate. Subsequent to this initial rapid subsidence, we found that PFD deformation slowed to a more persistent, linear, long-term rate, related to cooling of the deposits. We established that the deposits' contraction rate is linearly related to their thickness and measured the contraction rate. Finally, a study of long term coherence properties of the Augustine PFDs showed remarkable stability of the surface over long time periods. This information provides clues on the structural properties and composition of the emplaced material.

  13. Inverse modeling of InSAR and ground leveling data for 3D volumetric strain distribution (United States)

    Gallardo, L. A.; Glowacka, E.; Sarychikhina, O.


    Wide availability of modern Interferometric Synthetic aperture Radar (InSAR) data have made possible the extensive observation of differential surface displacements and are becoming an efficient tool for the detailed monitoring of terrain subsidence associated to reservoir dynamics, volcanic deformation and active tectonism. Unfortunately, this increasing popularity has not been matched by the availability of automated codes to estimate underground deformation, since many of them still rely on trial-error subsurface model building strategies. We posit that an efficient algorithm for the volumetric modeling of differential surface displacements should match the availability of current leveling and InSAR data and have developed an algorithm for the joint inversion of ground leveling and dInSAR data in 3D. We assume the ground displacements are originated by a stress free-volume strain distribution in a homogeneous elastic media and determined the displacement field associated to an ensemble of rectangular prisms. This formulation is then used to develop a 3D conjugate gradient inversion code that searches for the three-dimensional distribution of the volumetric strains that predict InSAR and leveling surface displacements simultaneously. The algorithm is regularized applying discontinuos first and zero order Thikonov constraints. For efficiency, the resulting computational code takes advantage of the resulting convolution integral associated to the deformation field and some basic tools for multithreading parallelization. We extensively test our algorithm on leveling and InSAR test and field data of the Northwest of Mexico and compare to some feasible geological scenarios of underground deformation.

  14. Space-Borne and Ground-Based InSAR Data Integration: The Åknes Test Site

    Directory of Open Access Journals (Sweden)

    Federica Bardi


    Full Text Available This work concerns a proposal of the integration of InSAR (Interferometric Synthetic Aperture Radar data acquired by ground-based (GB and satellite platforms. The selected test site is the Åknes rockslide, which affects the western Norwegian coast. The availability of GB-InSAR and satellite InSAR data and the accessibility of a wide literature make the landslide suitable for testing the proposed procedure. The first step consists of the organization of a geodatabase, performed in the GIS environment, containing all of the available data. The second step concerns the analysis of satellite and GB-InSAR data, separately. Two datasets, acquired by RADARSAT-2 (related to a period between October 2008 and August 2013 and by a combination of TerraSAR-X and TanDEM-X (acquired between July 2010 and October 2012, both of them in ascending orbit, processed applying SBAS (Small BAseline Subset method, are available. GB-InSAR data related to five different campaigns of measurements, referred to the summer seasons of 2006, 2008, 2009, 2010 and 2012, are available, as well. The third step relies on data integration, performed firstly from a qualitative point of view and later from a semi-quantitative point of view. The results of the proposed procedure have been validated by comparing them to GPS (Global Positioning System data. The proposed procedure allowed us to better define landslide sectors in terms of different ranges of displacements. From a qualitative point of view, stable and unstable areas have been distinguished. In the sector concerning movement, two different sectors have been defined thanks to the results of the semi-quantitative integration step: the first sector, concerning displacement values higher than 10 mm, and the 2nd sector, where the displacements did not exceed a 10-mm value of displacement in the analyzed period.

  15. Study of the deformation in Central Afar using InSAR NSBAS chain (United States)

    Deprez, A.; Doubre, C.; Grandin, R.; Saad, I.; Masson, F.; Socquet, A.


    The Afar Depression (East Africa) connects all three continental plates of Arabia, Somalia and Nubia plates. For over 20 Ma, the divergent motion of these plates has led to the formation of large normal faults building tall scarps between the high plateaus and the depression, and the development of large basins and an incipient seafloor spreading along a series of active volcano-tectonic rift segments within the depression. The space-time evolution of the active surface deformation over the whole Afar region remains uncertain. Previous tectonic and geodetic studies confirm that a large part of the current deformation is concentrated along these segments. However, the amount of extension accommodated by other non-volcanic basins and normal faulting remains unclear, despite significant micro-seismic activity. Due to the active volcanism, large transient displacements related to dyking sequence, notably in the Manda Hararo rift (2005-2010), increase the difficulty to characterize the deformation field over simple time and space scales. In this study, we attempt to obtain a complete inventory of the deformation within the whole Afar Depression and to understand the associated phenomena, which occurred in this singular tectonic environment. We study in particular, the behavior of the structures activated during the post-dyking stage of the rift segments. For this purpose, we conduct a careful processing of a large set of SAR ENVISAT images over the 2004-2010 period, we also use previous InSAR results and GPS data from permanent stations and from campaigns conducted in 1999, 2003, 2010, 2012 within a GPS network particularly dense along the Asal-Ghoubbet segment. In one hand, in the western part of Afar, the far-field response of the 2005-2010 dyke sequence appears to be the dominant surface motion on the mean velocity field. In an other hand, more eastward across the Asal-Ghoubbet rift, strong gradients of deformation are observed. The time series analysis of both InSAR

  16. Forward-looking three dimensional imaging technique for InSAR mounted on ground vehicles%车载 InSAR 前视三维成像技术

    Institute of Scientific and Technical Information of China (English)

    王建; 李杨寰; 张汉华; 陆必应; 宋千; 周智敏


    It is a difficult task for an unmanned ground vehicle (UGV)to sense obstacles in out fields or unstructured environments.Because the height information is a vital feature to boost the performance of obstacle discrimination,the three-dimensional imaging technique for sensing obstacles ahead UGV of interferometric synthetic aperture radar (InSAR)was presented.The basic signal process flow of InSAR was reviewed. Special factors of the UGV platform that impact the digital elevation model (DEM)measurement precision were analyzed,such as the baseline length,platform motion errors.The DEMof a partial sight-blocked obstacle scene was obtained by processing the three-dimensional InSAR image, which proved the feasibility of applying InSAR to obstacle sensing of UGV.%野外和非结构化环境下的障碍探测是无人驾驶车(UGV)环境感知的难题之一。基于高度识别障碍是一种有效的解决途径,提出了干涉合成孔径雷达(InSAR)的三维障碍物成像策略,研究了 InSAR 信息处理流程,分析了干涉基线和运动误差对车载 InSAR 高程测量精度的影响,仿真了无人车前场景存在遮挡时的 InSAR 高程测量,证明了 InSAR 用于 UGV 前方环境感知的可行性。

  17. Engaging students in geodesy: A quantitative InSAR module for undergraduate tectonics and geophysics classes (United States)

    Taylor, H.; Charlevoix, D. J.; Pritchard, M. E.; Lohman, R. B.


    In the last several decades, advances in geodetic technology have allowed us to significantly expand our knowledge of processes acting on and beneath the Earth's surface. Many of these advances have come as a result of EarthScope, a community of scientists conducting multidisciplinary Earth science research utilizing freely accessible data from a variety of instruments. The geodetic component of EarthScope includes the acquisition of synthetic aperture radar (SAR) images, which are archived at the UNAVCO facility. Interferometric SAR complements the spatial and temporal coverage of GPS and allows monitoring of ground deformation in remote areas worldwide. However, because of the complex software required for processing, InSAR data are not readily accessible to most students. Even with these challenges, exposure at the undergraduate level is important for showing how geodesy can be applied in various areas of the geosciences and for promoting geodesy as a future career path. Here we present a module focused on exploring the tectonics of the western United States using InSAR data for use in undergraduate tectonics and geophysics classes. The module has two major objectives: address topics concerning tectonics in the western U.S. including Basin and Range extension, Yellowstone hotspot activity, and creep in southern California, and familiarize students with how imperfect real-world data can be manipulated and interpreted. Module questions promote critical thinking skills and data literacy by prompting students to use the information given to confront and question assumptions (e.g. 'Is there a consistency between seismic rates and permanent earthquake deformation? What other factors might need to be considered besides seismicity?'). The module consists of an introduction to the basics of InSAR and three student exercises, each focused on one of the topics listed above. Students analyze pre-processed InSAR data using MATLAB, or an Excel equivalent, and draw on GPS and

  18. Subsidence Detection Using InSAR and Geodetic Measurements in the North-West of Iran (United States)

    Sedighi, Morteza


    The subsidence of the Earth surface is a phenomenon that occurs in some places in the world which overuse underground sources of water. As Iran has semi-arid and arid climate and the rate of rainfall is lower than the mean rate in the world then nowadays we are encountered by over-exploitation of groundwater in agricultural areas and also for extending the cities and industrial areas. Geodetic measurements i.e., repeated leveling measurements of first order leveling network of Iran and continuous GPS measurements of Iranian Permanent GPS Network of Iran (IPGN), showed that there are subsidence areas in the north-west of Iran. In this paper we try to find the area and rate of subsidence in the north-west of Iran using InSAR and geodetic techniques. The result of InSAR technique shows a better understanding on this phenomenon in these areas and has a good consistency with accurate geodetic measurements.

  19. Slope deformations in high-mountain regions as observed by InSAR: Examples from the Cordillera Blanca, Peru (United States)

    Frey, Holger; Strozzi, Tazio; Caduff, Rafael; Huggel, Christian; Klimeš, Jan; Vilímek, Vít; Wiesmann, Andreas; Kääb, Andreas; Cochachin, Alejo; Plummer, Stephen


    the dry period. Data archives of spaceborne SAR sensors such as ERS-1/2, ENVISAT, ALOS PALSAR-1/2, TerraSAR-X, Radarsat-2 and Sentinel-1 provide information reaching back to the 1990ies, allowing for detection and analysis of both current and past processes. Environmental conditions in the Peruvian Andes are particularly favourable for InSAR analyses, with an extended period of mostly cloud-free conditions during austral winter (dry season), sparse vegetation cover and only very limited snow coverage, factors that in other regions often limit the potential of this technology. This contribution shows the potential of InSAR products, providing unique information on slope deformations and surface displacements as identified as an important information source for integrative hazard assessments and glaciological investigations in high-mountain regions. In particular in combination with field investigations this technology is very powerful, not only for hazard research, but for other types of applications related to surface displacements and terrain deformations. In regions like the Cordillera Blanca, where a variety of potentially hazardous and interacting processes are present, often under conditions beyond historical evidences, such data products provide invaluable information for hazard assessments, early detection of hazard potentials, and a basis for prioritization and decision-making by the authorities.

  20. Monitoring CO2 sequestration with a network inversion InSAR method (United States)

    Rabus, B.; Ghuman, P.; MacDonald, B.


    The capture, containment and long-term storage of CO2 is increasingly discussed as an important means to counter climate change resulting from the ongoing release of greenhouse gases into the atmosphere. This CO2 sequestration often requires the pumping of the gas into deep saline aquifers. However, before sequestration can be regarded as a longterm solution it is necessary to investigate under which conditions permanent and leakless capture of the CO2 is achieved in the substrate. We demonstrate that a combination of spaceborne synthetic aperture interferometry (InSAR) and ground based measurements of ground uplift caused by the underground release and spreading of the CO2 can be forged into a powerful tool to monitor sequsetration. We use a novel InSAR approach, which combines the benefits of a point-based persistent scatterer algorithm with a network inversion approach, and an additional temporal filter to remove atmospheric disturbances also at smaller scales down to 1 km and less. Using case studies from several injection wells we show that InSAR and ground based data in conjunction with geological and structural information above the aquifer, as well as detailed injection logs, allow to monitor the volumetric spread of CO2 at the mm per year level. For the majority of the studied wells CO2 appears to approach a stable sequestration state, however, in at least one case our results suggest leakage outside the aquifer.

  1. Retrieving three-dimensional displacement fields of mining areas from a single InSAR pair (United States)

    Li, Zhi Wei; Yang, Ze Fa; Zhu, Jian Jun; Hu, Jun; Wang, Yun Jia; Li, Pei Xian; Chen, Guo Liang


    This paper presents a novel method for retrieving three-dimensional (3-D) displacement fields of mining areas from a single interferometric synthetic aperture radar (InSAR) pair. This method fully exploits the mechanism of mining subsidence, specifically the proportional relationship between the horizontal displacement and horizontal gradient of vertical displacements caused by underground mining. This method overcomes the limitations of conventional InSAR techniques that can only measure one-dimensional (1-D) deformation of mining area along the radar line-of-sight direction. The proposed method is first validated with simulated 3-D displacement fields, which are obtained by the FLAC software. The root mean square errors of the 3-D displacements retrieved by the proposed method are 13.7, 27.6 and 3.6 mm for the West-East, North-South, and Up-Down components, respectively. We then apply the proposed method to estimate the 3-D displacements of the Qianyingzi and the Xuzhou coal mines in China, respectively, each along with two Advanced Land Observing Satellite (ALOS) Phased Array Type L-band Synthetic Aperture Radar images. Results show that the estimated 3-D displacement is highly consistent with that of the field surveying. This demonstrates that the proposed method is an effective approach for retrieving 3-D mining displacement fields and will play an important role in mining-related hazard prevention and environment assessment under limited InSAR acquisitions.

  2. Anatomy of Subsidence in Tianjin from Time Series InSAR

    Directory of Open Access Journals (Sweden)

    Peng Liu


    Full Text Available Groundwater is a major source of fresh water in Tianjin Municipality, China. The average rate of groundwater extraction in this area for the last 20 years fluctuates between 0.6 and 0.8 billion cubic meters per year. As a result, significant subsidence has been observed in Tianjin. In this study, C-band Envisat (Environmental Satellite ASAR (Advanced Synthetic Aperture Radar images and L-band ALOS (Advanced Land Observing Satellite PALSAR (Phased Array type L-band Synthetic Aperture Radar data were employed to recover the Earth’s surface evolution during the period between 2007 and 2009 using InSAR time series techniques. Similar subsidence patterns can be observed in the overlapping area of the ASAR and PALSAR mean velocity maps with a maximum radar line of sight rate of ~170 mm·year−1. The west subsidence is modeled for ground water volume change using Mogi source array. Geological control by major faults on the east subsidence is analyzed. Storage coefficient of the east subsidence is estimated by InSAR displacements and temporal pattern of water level changes. InSAR has proven a useful tool for subsidence monitoring and displacement interpretation associated with underground water usage.

  3. Monitoring and characterizing natural hazards with satellite InSAR imagery (United States)

    Lu, Zhong; Zhang, Jixian; Zhang, Yonghong; Dzurisin, Daniel


    Interferometric synthetic aperture radar (InSAR) provides an all-weather imaging capability for measuring ground-surface deformation and inferring changes in land surface characteristics. InSAR enables scientists to monitor and characterize hazards posed by volcanic, seismic, and hydrogeologic processes, by landslides and wildfires, and by human activities such as mining and fluid extraction or injection. Measuring how a volcano’s surface deforms before, during, and after eruptions provides essential information about magma dynamics and a basis for mitigating volcanic hazards. Measuring spatial and temporal patterns of surface deformation in seismically active regions is extraordinarily useful for understanding rupture dynamics and estimating seismic risks. Measuring how landslides develop and activate is a prerequisite to minimizing associated hazards. Mapping surface subsidence or uplift related to extraction or injection of fluids during exploitation of groundwater aquifers or petroleum reservoirs provides fundamental data on aquifer or reservoir properties and improves our ability to mitigate undesired consequences. Monitoring dynamic water-level changes in wetlands improves hydrological modeling predictions and the assessment of future flood impacts. In addition, InSAR imagery can provide near-real-time estimates of fire scar extents and fire severity for wildfire management and control. All-weather satellite radar imagery is critical for studying various natural processes and is playing an increasingly important role in understanding and forecasting natural hazards.

  4. Block adjustment of airborne InSAR based on interferogram phase and POS data (United States)

    Yue, Xijuan; Zhao, Yinghui; Han, Chunming; Dou, Changyong


    High-precision surface elevation information in large scale can be obtained efficiently by airborne Interferomatric Synthetic Aperture Radar (InSAR) system, which is recently becoming an important tool to acquire remote sensing data and perform mapping applications in the area where surveying and mapping is difficult to be accomplished by spaceborne satellite or field working. . Based on the study of the three-dimensional (3D) positioning model using interferogram phase and Position and Orientation System (POS) data and block adjustment error model, a block adjustment method to produce seamless wide-area mosaic product generated from airborne InSAR data is proposed in this paper. The effect of 6 parameters, including trajectory and attitude of the aircraft, baseline length and incline angle, slant range, and interferometric phase, on the 3D positioning accuracy is quantitatively analyzed. Using the data acquired in the field campaign conducted in Mianyang county Sichuan province, China in June 2011, a mosaic seamless Digital Elevation Model (DEM) product was generated from 76 images in 4 flight strips by the proposed block adjustment model. The residuals of ground control points (GCPs), the absolute positioning accuracy of check points (CPs) and the relative positioning accuracy of tie points (TPs) both in same and adjacent strips were assessed. The experimental results suggest that the DEM and Digital Orthophoto Map (DOM) product generated by the airborne InSAR data with sparse GCPs can meet mapping accuracy requirement at scale of 1:10 000.

  5. Nyamulagira’s magma plumbing system inferred from 15 years of InSAR (United States)

    Wauthier, Christelle; Cayol, Valerie; Poland, Michael; Kervyn, François; D'Oreye, Nicolas; Hooper, Andrew; Samsonov, Sergei; Tiampo, Kristy; Smets, Benoit; Pyle, D. M.; Mather, T.A.; Biggs, J.


    Nyamulagira, located in the east of the Democratic Republic of Congo on the western branch of the East African rift, is Africa’s most active volcano, with an average of one eruption every 3 years since 1938. Owing to the socio-economical context of that region, the volcano lacks ground-based geodetic measurements but has been monitored by interferometric synthetic aperture radar (InSAR) since 1996. A combination of 3D Mixed Boundary Element Method and inverse modelling, taking into account topography and source interactions, is used to interpret InSAR ground displacements associated with eruptive activity in 1996, 2002, 2004, 2006 and 2010. These eruptions can be fitted by models incorporating dyke intrusions, and some (namely the 2006 and 2010 eruptions) require a magma reservoir beneath the summit caldera. We investigate inter-eruptive deformation with a multi-temporal InSAR approach. We propose the following magma plumbing system at Nyamulagira by integrating numerical deformation models with other available data: a deep reservoir (c. 25 km depth) feeds a shallower reservoir (c. 4 km depth); proximal eruptions are fed from the shallow reservoir through dykes while distal eruptions can be fed directly from the deep reservoir. A dyke-like conduit is also present beneath the upper southeastern flank of Nyamulagira.

  6. InSAR elevation bias caused by penetration into uniform volumes

    DEFF Research Database (Denmark)

    Dall, Jørgen


    SAR) biased downward. For infinitely deep uniform volumes, the elevation bias is often equated with the penetration depth, but this paper, it is shown that the two quantities generally differ. The interferometric bias is approximately equal to the two-way power-penetration depth if the latter is small......Natural media like cold-land ice, vegetation, and dry sand are subject to a substantial penetration at microwave frequencies. For such media, the synthetic aperture radar (SAR) ase center is located below the surface, and consequently, the surface elevation determined with SAR interferometry (In...... compared to the ambiguity height, but for increasing penetration depth, the bias approaches one quarter of the ambiguity height. Consequently, phase wrapping results even if the penetration depth exceeds ambiguity height. The ratio of the InSAR elevation bias to ambiguity height depends only on the ratio...


    Directory of Open Access Journals (Sweden)

    F. C. Çomut


    Full Text Available The SAR Interferometry (InSAR application has shown great potential in monitoring of land terrain changes and in detection of land deformations such as subsidence. Longer time analysis can lead to understand longer trends and changes. Using different bands of SAR satellite (C- from ERS 1-2 and Envisat, L- from ALOS over the study area, we achieve knowledge of movements in long-term and evaluation of its dynamic changes within observed period of time. Results from InSAR processing fit with the position changes in vertical direction based on GPS network established over the basin as an effective geodetic network. Time series (StaMPS PS+SB of several points over Çumra County in eastern part of Konya City show a general trend of the deformation that is expected to be approximately between -13 to -17 mm/year. Northern part of Karaman is affected by faster subsidence, borders of the subsidence trough were identified from Envisat. Presenting InSAR results together with GIS information about locations and time of occurrence of sudden subsidence, urban/industrial growth in time and climate changes helps in better understanding of the situation. This way, the impact of natural and man-made changes will be shown for urban planning thanks to InSAR and GIS comparisons with hydrogeological modeling. In this study we present results of differential and multitemporal InSAR series using different bands and GIS conjunction associated with seasonal and temporal groundwater level changes in Konya Closed Basin.

  8. Multi Band Insar Analysis of Subsidence Development Based on the Long Period Time Series (United States)

    Çomut, F. C.; Ustun, A.; Lazecky, M.; Aref, M. M.


    The SAR Interferometry (InSAR) application has shown great potential in monitoring of land terrain changes and in detection of land deformations such as subsidence. Longer time analysis can lead to understand longer trends and changes. Using different bands of SAR satellite (C- from ERS 1-2 and Envisat, L- from ALOS) over the study area, we achieve knowledge of movements in long-term and evaluation of its dynamic changes within observed period of time. Results from InSAR processing fit with the position changes in vertical direction based on GPS network established over the basin as an effective geodetic network. Time series (StaMPS PS+SB) of several points over Çumra County in eastern part of Konya City show a general trend of the deformation that is expected to be approximately between -13 to -17 mm/year. Northern part of Karaman is affected by faster subsidence, borders of the subsidence trough were identified from Envisat. Presenting InSAR results together with GIS information about locations and time of occurrence of sudden subsidence, urban/industrial growth in time and climate changes helps in better understanding of the situation. This way, the impact of natural and man-made changes will be shown for urban planning thanks to InSAR and GIS comparisons with hydrogeological modeling. In this study we present results of differential and multitemporal InSAR series using different bands and GIS conjunction associated with seasonal and temporal groundwater level changes in Konya Closed Basin.

  9. Towards Slow-Moving Landslide Monitoring by Integrating Multi-Sensor InSAR Time Series Datasets: The Zhouqu Case Study, China

    Directory of Open Access Journals (Sweden)

    Qian Sun


    Full Text Available Although the past few decades have witnessed the great development of Synthetic Aperture Radar Interferometry (InSAR technology in the monitoring of landslides, such applications are limited by geometric distortions and ambiguity of 1D Line-Of-Sight (LOS measurements, both of which are the fundamental weakness of InSAR. Integration of multi-sensor InSAR datasets has recently shown its great potential in breaking through the two limits. In this study, 16 ascending images from the Advanced Land Observing Satellite (ALOS and 18 descending images from the Environmental Satellite (ENVISAT have been integrated to characterize and to detect the slow-moving landslides in Zhouqu, China between 2008 and 2010. Geometric distortions are first mapped by using the imaging geometric parameters of the used SAR data and public Digital Elevation Model (DEM data of Zhouqu, which allow the determination of the most appropriate data assembly for a particular slope. Subsequently, deformation rates along respective LOS directions of ALOS ascending and ENVISAT descending tracks are estimated by conducting InSAR time series analysis with a Temporarily Coherent Point (TCP-InSAR algorithm. As indicated by the geometric distortion results, 3D deformation rates of the Xieliupo slope at the east bank of the Pai-lung River are finally reconstructed by joint exploiting of the LOS deformation rates from cross-heading datasets based on the surface–parallel flow assumption. It is revealed that the synergistic results of ALOS and ENVISAT datasets provide a more comprehensive understanding and monitoring of the slow-moving landslides in Zhouqu.

  10. Time series analysis of strain accumulation along the Haiyuan fault (Gansu, China) over the 1993-2009 period, from ERS and ENVISAT InSAR data (United States)

    Jolivet, Romain; Lasserre, Cecile; Doin, Marie-Pierre; Guillaso, Stéphane; Cavalié, Olivier; Peltzer, Gilles; Sun, Jianbao; Rong, Dailu; Shen, Zheng-Kang; Xu, Xiwei


    We use SAR interferometry to measure the strain accumulation along the left-lateral Haiyuan fault system (HFS), that marks the north-eastern boundary of the tibetan plateau. The last major earthquakes that occured along the HFS are the M~8 1920 Haiyuan earthquake (strike-slip mechanism) and the Ml=8-8.3 1927 Gulang earthquake that ruptured a thrust fault system. No large earthquake is reported on the central section of the HFS, the "Tianzhu seismic gap", since ~1000 years. We first analyze the complete ENVISAT SAR data archive along 4 descending and 2 ascending tracks for the 2003-2009 period and construct an InSAR-based mean Line-Of-Sight (LOS) velocity map around the HFS from the eastern end of the Qilian shan (102° E), to the west, to the Liupan shan (106° E), to the east. Data are processed using a small baseline chain type. For each track, all radar images are coregistrated to a single master and interferograms are produced using a local adaptative range filtering. Residual orbital and atmospheric delays are jointly inverted and corrected for each unwrapped interferogram. Atmospheric corrections are validated using the ERA40 global atmospheric model (ECMWF). The interferograms series on each track are then inverted to obtain the increments of LOS radar delays between acquisition dates, adapting the Lopez-Quiroz et al. 2009 time series analysis. The obtained LOS mean velocity maps show a dominant left-lateral motion across the fault with along-strike variations: some fault sections are locked at shallow depth while others are creeping and local vertical movements are observed (subsidence in the "Jingtai" pull-apart basin). For various fault slip rates imposed below 20 km (4-10 mm/yr), we model the shallow velocity by inverting the mean LOS velocity maps for both strike-slip and dip-slip motion on vertical, 5km x 2.5km discretized patches, using a least-square method with an appropriate degree of smoothing. The fault geometry follows the surface trace of the

  11. Towards a high resolution inventory of anthropogenic deformation in North America using InSAR (United States)

    Pritchard, M. E.; Lohman, R. B.; Taylor, H.; Semple, A.; Valentino, B.


    Anthropogenic surface deformation is important to measure for several reasons -- 1) it could be a hazard to infrastructure; 2) it could contaminate precise measurements of other types of deformation (e.g., magmatic or tectonic); and 3) the deformation can provide otherwise inaccessible information about the subsurface as we measure the Earth's response to known pumping, surface change, or mining activity. While there are studies at individual sites in North America that demonstrate these three types of studies, we lack a continental synoptic view of anthropogenic deformation and its significance. To fill this gap, we use satellite Interferometric Synthetic Aperture Radar (InSAR) data to image ground deformation across the continent with a spatial resolution of 1 km/pixel or better using results from the literature as well as new analysis of more than 5000 interferograms from the ERS, Envisat, and ALOS satellites, which collectively span 1992-2011. Our compilation is not complete in terms of spatially or temporal coverage nor is it uniform in quality over the region -- certainly we have missed some areas of deformation. Most of the data analyzed is in the western US, but ALOS observations east of the Rocky Mountains are of good quality even in vegetated and snowy areas and we document mining subsidence greater than several cm per year in NY, PA, and WV. We catalog more than 200 anthropogenic deformation signals, including about 45 that are not previously reported. The majority of these deformation sources can be attributed to groundwater extraction (66%), 8% to geothermal activity, 13% to hydrocarbon extraction, 11% to mining activity, and 2% to other sources such as lake loading. In a few areas, the source of deformation is not yet determined. As expected, most deformation is time dependent and so continuous monitoring is needed. In some areas, comparisonbetween pumping records and surface deformation reveals some suprises. For example, at the East Mesa Geothermal

  12. Rapid groundwater-related land subsidence in Yemen observed by multi-temporal InSAR

    KAUST Repository

    Abdullin, Ayrat


    of some of the basins. Our results highlight the usefulness of InSAR in monitoring land subsidence in areas where limited or no conventional geodetic observations are carried out. Future work will focus on obtaining more InSAR and well pressure data and on analyzing further the subsidence and its connection with the groundwater reservoir pressure distribution.

  13. Time series analysis of strain accumulation across the Haiyuan fault, Gansu, China, over the 2003-2009 period from ENVISAT InSAR data (United States)

    Jolivet, R.; Lasserre, C.; Doin, M.; Guillaso, S.; Cavalie, O.; Peltzer, G.; Sun, J.; Shen, Z.


    We use sar interferometry to characterize the present-day behaviour of the left-lateral Haiyuan fault system (HFS), one of the main geological structure at the north-eastern boundary of the tibetan plateau that accomodates the eastward movement of Tibet relative to the Gobi-Ala Shan platform. The last major earthquakes that occured along the HFS are the M~8 1920 Haiyuan earthquake (strike-slip mechanism) and the Ml=8-8.3 1927 Gulang earthquake that ruptured a nearby thrust fault system. A ~260 km-long seismic gap has been identified on the central part of the HFS, along which creep may occur. We propose to further investigate the relationships between the present day deformation processes observed along the HFS and its seismic history and segmentation. We construct an extended InSAR-based map of the deformation around the Haiyuan fault from the eastern end of the Qilian Shan (102° E), to the west, to the junction with the Liupan Shan (106° E), to the east. We use monthly ENVISAT acquisitions along 4 descending and 2 ascending tracks, spanning the 2003-2009 time period. Data are processed using a small baseline chain type. For each track, all radar images are coregistrated to a single master and interferograms are produced using a local adaptative range filtering. Residual orbital and atmospheric effects are jointly inverted and corrected for each unwrapped interferogram. Atmospheric corrections are validated “a posteriori” , using the most recent global atmospheric model. We also investigate the potential improvements of these models for “a priori” atmospheric corrections. The interferograms series on each track are then inverted to obtain the increments of Line Of Sight (LOS) radar delays between acquisition dates, adapting the Lopez-Quiroz et al. 2009 time series analysis. We derive LOS mean velocity maps, that show along-strike variations including local shallow creep and vertical movements (subsidence in the Jingtai pull-apart basin). These features

  14. Vegetation, smegetation: How InSAR research on tectonics and land surface change has expanded from the deserts to the rain forests and beyond. (United States)

    Lohman, R. B.


    The upcoming avalanche of openly available SAR imagery is expanding the horizons of what can and cannot be accomplished with InSAR. Historically, InSAR performed best in arid regions - an observation that became a bit of a self-fulfilling prophecy as satellite agencies acquired less data in regions with vegetation and agricultural activity. Here we present an overview of the development of InSAR research in tectonics and land surface change over the past 2+ decades, with a view towards some of the new advances in modeling and data management that will be necessary to fully take advantage of SAR data in the near future. One of the most basic breakthroughs will be that issues with decorrelation and the need for sophisticated time series analysis just to enable phase unwrapping will no longer be a major problem over many areas of the globe. New challenges will be the interpretation of coherent signal related to vegetation, soil moisture and time-variable phase scattering height in regions that previously would have just been flagged as "noise". We present results based on the ingestion of independent optical and radar observation types into SAR time series analysis, with applications to deformation sources in the Central and Eastern United States.The land surface properties in the Central and Eastern United States differ from those in the arid regions where InSAR has often been used, both in the presence of vegetation and the often very rapid changes in surface scattering characteristics that occur seasonally and during single events (snowfall, flooding, etc.). In the past, observations were so sparse that these changes resulted in decorrelation, rendering the data unusable. However, shorter acquisition times and a wider range of radar wavelengths allow the extraction of coherent signals from these areas, even spanning large snow storms. The resulting data contain signals that were often disregarded during InSAR time series analysis, but that must be either accounted

  15. Post-Eruptive Inflation of Okmok Volcano, Alaska, from InSAR, 2008–2014

    Directory of Open Access Journals (Sweden)

    Feifei Qu


    Full Text Available Okmok, a ~10-km wide caldera that occupies most of the northeastern end of Umnak Island, is one of the most active volcanoes in the Aleutian arc. The most recent eruption at Okmok during July–August 2008 was by far its largest and most explosive since at least the early 19th century. We investigate post-eruptive magma supply and storage at the volcano during 2008–2014 by analyzing all available synthetic aperture radar (SAR images of Okmok acquired during that time period using the multi-temporal InSAR technique. Data from the C-band Envisat and X-band TerraSAR-X satellites indicate that Okmok started inflating very soon after the end of 2008 eruption at a time-variable rate of 48–130 mm/y, consistent with GPS measurements. The “model-assisted” phase unwrapping method is applied to improve the phase unwrapping operation for long temporal baseline pairs. The InSAR time-series is used as input for deformation source modeling, which suggests magma accumulating at variable rates in a shallow storage zone at ~3.9 km below sea level beneath the summit caldera, consistent with previous studies. The modeled volume accumulation in the six years following the 2008 eruption is ~75% of the 1997 eruption volume and ~25% of the 2008 eruption volume.

  16. Monitoring Crustal Deformation by GPS and InSAR in the Three Gorge Area

    Institute of Scientific and Technical Information of China (English)


    The on-going Three Gorges Project (TGP) aims to build one of the largest hydropower stations in the world. Previous investigations have concluded that the reservoir is likely to induce medium-to-intense earthquakes. 23 GPS stations have been established to maintain a geodetic and seismological monitoring network around the reservoir to monitor seismicity and crustal deformation, and to facilitate mitigation activities in case an intense earthquake occurs. The velocity of GPS site was derived from 3 repeated GPS surveys. Meanwhile, another effort has been made to investigate the feasibility of application of satellite interferometric synthetic aperture radar (InSAR) techniques in detecting crustal deformation possibly caused by impoundment of the Three Gorges Reservoir. It has been made to derive digital elevation models (DEM) using European Remote Sensing (ERS) synthetic aperture radar (SAR) imagery. Pairs of ERS SAR images in raw format are processed to generate digital elevation models. This effort will help us evaluate the accuracy of the InSAR techniques for further derivation of background deformation patterns and future detection of reservoir-induced crustal deformation in the area.

  17. Post-eruptive inflation of Okmok Volcano, Alaska, from InSAR, 2008–2014 (United States)

    Qu, Feifei; Lu, Zhong; Poland, Michael; Freymueller, Jeffrey T.; Zhang, Qin; Jung, Hyung-Sup


    Okmok, a ~10-km wide caldera that occupies most of the northeastern end of Umnak Island, is one of the most active volcanoes in the Aleutian arc. The most recent eruption at Okmok during July-August 2008 was by far its largest and most explosive since at least the early 19th century. We investigate post-eruptive magma supply and storage at the volcano during 2008–2014 by analyzing all available synthetic aperture radar (SAR) images of Okmok acquired during that time period using the multi-temporal InSAR technique. Data from the C-band Envisat and X-band TerraSAR-X satellites indicate that Okmok started inflating very soon after the end of 2008 eruption at a time-variable rate of 48-130 mm/y, consistent with GPS measurements. The “model-assisted” phase unwrapping method is applied to improve the phase unwrapping operation for long temporal baseline pairs. The InSAR time-series is used as input for deformation source modeling, which suggests magma accumulating at variable rates in a shallow storage zone at ~3.9 km below sea level beneath the summit caldera, consistent with previous studies. The modeled volume accumulation in the 6 years following the 2008 eruption is ~75% of the 1997 eruption volume and ~25% of the 2008 eruption volume.

  18. InSAR and GPS measurements of crustal deformation due to seasonal loading of Tehri reservoir in Garhwal Himalaya, India (United States)

    Gahalaut, V. K.; Yadav, Rajeev K.; Sreejith, K. M.; Gahalaut, Kalpna; Bürgmann, Roland; Agrawal, Ritesh; Sati, S. P.; Kumar, Amit


    We report unique observations of crustal deformation caused by the seasonal water level changes of Tehri reservoir in the Garhwal region of NW Himalaya from GPS measurements and Interferometric Synthetic Aperture Radar (InSAR) analysis. All GPS sites along the Himalaya are strongly influenced by seasonal hydrological and atmospheric loading. However, the GPS site KUNR located near the reservoir additionally exhibits anomalous variations due to seasonal water loading and unloading by the reservoir. Our InSAR analysis confirms that the seasonal filling of the reservoir causes measurable subsidence in its neighbourhood. In addition to the elastic deformation caused by the seasonal reservoir loading and the negligible poroelastic deformation caused by associated fluid pressure changes, there is an unaccounted for biannual deformation in the east component of the GPS time series which we suspect to be caused by altered hydrological conditions due to the reservoir operations. Understanding crustal deformation processes due to such anthropogenic sources helps in separating deformation caused by tectonic, hydrological and atmospheric effects from that caused by these activities.

  19. The 2008 Wells, Nevada earthquake sequence: Source constraints using calibrated multiple event relocation and InSAR (United States)

    Nealy, Jennifer; Benz, Harley M.; Hayes, Gavin; Berman, Eric; Barnhart, William


    The 2008 Wells, NV earthquake represents the largest domestic event in the conterminous U.S. outside of California since the October 1983 Borah Peak earthquake in southern Idaho. We present an improved catalog, magnitude complete to 1.6, of the foreshock-aftershock sequence, supplementing the current U.S. Geological Survey (USGS) Preliminary Determination of Epicenters (PDE) catalog with 1,928 well-located events. In order to create this catalog, both subspace and kurtosis detectors are used to obtain an initial set of earthquakes and associated locations. The latter are then calibrated through the implementation of the hypocentroidal decomposition method and relocated using the BayesLoc relocation technique. We additionally perform a finite fault slip analysis of the mainshock using InSAR observations. By combining the relocated sequence with the finite fault analysis, we show that the aftershocks occur primarily updip and along the southwestern edge of the zone of maximum slip. The aftershock locations illuminate areas of post-mainshock strain increase; aftershock depths, ranging from 5 to 16 km, are consistent with InSAR imaging, which shows that the Wells earthquake was a buried source with no observable near-surface offset.

  20. Towards assimilation of InSAR data in operational weather models (United States)

    Mulder, Gert; van Leijen, Freek; Barkmeijer, Jan; de Haan, Siebren; Hanssen, Ramon


    InSAR signal delays due to the varying atmospheric refractivity are a potential data source to improve weather models [1]. Especially with the launch of the new Sentinel-1 satellites, which increases data coverage, latency and accessibility, it may become possible to operationalize the assimilation of differential integrated refractivity (DIR) values in numerical weather models. Although studies exist on comparison between InSAR data and weather models [2], the impact of assimilation of DIR values in an operational weather model has never been assessed. In this study we present different ways to assimilate DIR values in an operational weather model and show the first forecast results. There are different possibilities to assimilate InSAR-data in a weather model. For example, (i) absolute DIR values can be derived using additional GNSS zenith or slant delay values, (ii) DIR values can be converted to water vapor pressures, or (iii) water vapor pressures can be derived for different heights by combining GNSS and InSAR data. However, an increasing number of assumptions in these processing steps will increase the uncertainty in the final results. Therefore, we chose to insert the InSAR derived DIR values after minimal additional processing. In this study we use the HARMONIE model [3], which is a spectral, non-hydrostatic model with a resolution of about 2.5 km. Currently, this is the operational model in 11 European countries and based on the AROME model [4]. To assimilate the DIR values in the weather model we use a simple adjustment of the weather parameters over the full slant column to match the DIR values. This is a first step towards a more sophisticated approach based on the 3D-VAR or 4D-VAR schemes [5]. Where both assimilation schemes can correct for different weather parameters simultaneously, and 4D-VAR allow us to assimilate DIR values at the exact moment of satellite overpass instead of the start of the forecast window. The approach will be demonstrated

  1. Governance from space: Satellite InSAR observations to support decision-making and to avoid calamities (United States)

    Lambert, John; De Lange, Ger; Maccabiani, Jos


    Satellites are revolving around the earth already for over five decades, nowadays allowing us to have images of every location on our planet, using different techniques. These images are used for many different purposes, but the number of applications is still growing fast. In this paper, some practical applications of InSAR (Interferometric Synthetic Aperture Radar) data are described. The detection of trends in the movements of the earth surface and those of buildings and infrastructure is one of the applications for this infrastructure. InSAR data from the North-East Groningen gas field region show how large scale subsidence patterns can be detected and can support spatial planning strategies. Another case, in Diemen, shows how InSAR data support the municipal government in their management strategies. Another case shows how InSAR observations, taken from the entrance to the Vlaketunnel, could have warned in advance for the collapse of one of these entries. Finally, it will be shown that InSAR data can be helpful to monitor the effects of (underground) civil engineering activities, such as the construction of the North-Southline in Amsterdam.

  2. Monitoring of Three Case Studies of Creeping Landslides in Ecuador using L-band SAR Interferometry (InSAR) (United States)

    Mayorga Torres, T. M.; Mohseni Aref, M.


    Tannia Mayorga Torres1,21 Universidad Central del Ecuador. Faculty of Geology, Mining, Oil, and Environment 2 Hubert H. Humphrey Fellowship 2015-16 IntroductionLandslides lead to human and economic losses across the country, mainly in the winter season. On the other hand, satellite radar data has cost-effective benefits due to open-source software and free availability of data. With the purpose of establishing an early warning system of landslide-related surface deformation, three case studies were designed in the Coast, Sierra (Andean), and Oriente (jungle) regions. The objective of this work was to assess the capability of L-band InSAR to get phase information. For the calculation of the interferograms in Repeat Orbit Interferometry PACkage, the displacement was detected as the error and was corrected. The coherence images (Figure 1) determined that L-band is suitable for InSAR processing. Under this frame, as a first approach, the stacking DInSAR technique [1] was applied in the case studies [2]; however, due to lush vegetation and steep topography, it is necessary to apply advanced InSAR techniques [3]. The purpose of the research is to determine a pattern of data acquisition and successful results to understand the spatial and temporal ground movements associated with landslides. The further work consists of establishing landslide inventories to combine phases of SAR images to generate maps of surface deformation in Tumba-San Francisco and Guarumales to compare the results with ground-based measurements to determine the maps' accuracy. References[1] Sandwell D., Price E. (1998). Phase gradient approach to stacking interferograms. Journal of Geophysical Research, Vol. 103, N. B12, pp. 30,183-30,204. [2] Mayorga T., Platzeck G. (2014). Using DInSAR as a tool to detect unstable terrain areas in an Andes region in Ecuador. NH3.5-Blue Poster B298, Vol. 16, EGU2014-16203. Austria. [3] Wasowski J., Bovenga F. (2014). Investigating landslides and unstable slopes with

  3. Enhancement of long period components of recorded and synthetic ground motions using InSAR (United States)

    Abell, J.A.; Carlos de la Llera, J.; Wicks, C.W.


    Tall buildings and flexible structures require a better characterization of long period ground motion spectra than the one provided by current seismic building codes. Motivated by that, a methodology is proposed and tested to improve recorded and synthetic ground motions which are consistent with the observed co-seismic displacement field obtained from interferometric synthetic aperture radar (InSAR) analysis of image data for the Tocopilla 2007 earthquake (Mw=7.7) in Northern Chile. A methodology is proposed to correct the observed motions such that, after double integration, they are coherent with the local value of the residual displacement. Synthetic records are generated by using a stochastic finite-fault model coupled with a long period pulse to capture the long period fling effect. It is observed that the proposed co-seismic correction yields records with more accurate long-period spectral components as compared with regular correction schemes such as acausal filtering. These signals provide an estimate for the velocity and displacement spectra, which are essential for tall-building design. Furthermore, hints are provided as to the shape of long-period spectra for seismic zones prone to large co-seismic displacements such as the Nazca-South American zone. ?? 2011 Elsevier Ltd.

  4. A Constellation of CubeSat InSAR Sensors for Rapid-Revisit Surface Deformation Studies (United States)

    Wye, L.; Lee, S.; Yun, S. H.; Zebker, H. A.; Stock, J. D.; Wicks, C. W., Jr.; Doe, R.


    The 2007 NRC Decadal Survey for Earth Sciences highlights three major Earth surface deformation themes: 1) solid-earth hazards and dynamics; 2) human health and security; and 3) land-use change, ecosystem dynamics and biodiversity. Space-based interferometric synthetic aperture radar (InSAR) is a key change detection tool for addressing these themes. Here, we describe the mission and radar payload design for a constellation of S-band InSAR sensors specifically designed to provide the global, high temporal resolution, sub-cm level deformation accuracy needed to address some of the major Earth system goals. InSAR observations with high temporal resolution are needed to properly monitor certain nonlinearly time-varying features (e.g., unstable volcanoes, active fault lines, and heavily-used groundwater or hydrocarbon reservoirs). Good temporal coverage is also needed to reduce atmospheric artifacts by allowing multiple acquisitions to be averaged together, since each individual SAR measurement is corrupted by up to several cm of atmospheric noise. A single InSAR platform is limited in how often it can observe a given scene without sacrificing global spatial coverage. Multiple InSAR platforms provide the spatial-temporal flexibility required to maximize the science return. However, building and launching multiple InSAR platforms is cost-prohibitive for traditional satellites. SRI International (SRI) and our collaborators are working to exploit developments in nanosatellite technology, in particular the emergence of the CubeSat standard, to provide high-cadence InSAR capabilities in an affordable package. The CubeSat Imaging Radar for Earth Science (CIRES) subsystem, a prototype SAR elec­tronics package developed by SRI with support from a 2014 NASA ESTO ACT award, is specifically scaled to be a drop-in radar solution for resource-limited delivery systems like CubeSats and small airborne vehicles. Here, we present our mission concept and flow-down requirements for a

  5. Joint Assimilation of InSAR and Water-level Data for Aquifer Parameter Estimation and Groundwater State Forecasting in Santa Clara Valley, California (United States)

    Abdullin, Ayrat; Jonsson, Sigurjon


    Ground subsidence induced by groundwater withdrawal is a widespread problem and can cause damage to buildings and infrastructure. The challenge is to forecast, accurately and in a cost effective way, when water extraction may threaten infrastructure, so that procedures can be applied to avoid unacceptable levels of ground deformation beyond construction engineering criteria. However, many characteristics of the heterogeneity of aquifer parameters, such as hydraulic conductivity and storage coefficients, are usually uncertain. Monitoring data, such as water-level data in monitoring wells, can be used to reduce these uncertainties, but the difficulty is that they usually only provide spatially limited information about the groundwater system. To take on these problems, we use an ensemble-based assimilation framework that efficiently integrates InSAR-derived displacements and hydraulic head data for improved understanding of groundwater reservoir behavior. We apply this framework for aquifer parameter estimation of the basin-wide Santa Clara Valley groundwater system in northern California. To study the deformation patterns in the area, we use time-series analysis of InSAR data, based on more than 150 images from the ERS, Envisat and ALOS satellites from 1992-2012. Using the InSAR observations, in addition to approximate data on pumping, managed recharge and rainfall amounts, we are able to advance our understanding of the ongoing hydrogeological processes within the aquifer system. We find that including both InSAR and well water-level data as observations improves the properties estimation compared to basic statistical interpolation between the available well data. We also compare the performance of our hydraulic head predictions with previous groundwater studies in Santa Clara Valley, such as those of Chaussard et al. (2014). The results suggest that the high spatial resolution subsidence observations from InSAR are useful for accurately quantifying hydraulic

  6. Measuring Water Level Fluctuations of two Connected Wetlands in the Dominican Republic Using InSAR (United States)

    Pichardo Marcano, M. D.; Liu, L.; Zebker, H. A.


    Wetlands are ecosystems of high endemism and great biodiversity. Using the double-reflected radar waves off the water surface and trunks of inundated vegetation, Interferometric Synthetic Aperture Radar (InSAR) is capable of measuring water level fluctuations from space at a cm-level accuracy in these ecosystems with emergent vegetation. InSAR can provide a high spatial resolution over a large area that the more traditional terrestrial-based methods lack. In this study, we applied InSAR to study the seasonal variations in water level of the wetlands near two lakes in the southwest of the Dominican Republic: Lake Enriquillo, a highly saline lake designated as a Wetland of International Importance under the Ramsar Convention in 2002, and Laguna del Limon. Both lake-wetland systems are located in the Jaragua-Bahoruco-Enriquillo Biosphere Reserve. Since 2003 the water level of Lake Enriquillo has increased drastically and caused the evacuation of many farmers from nearby villages. Lake level changes also affected the habitats of several native and migratory species. We used the data acquired by the Phased Array type L-band Synthetic Aperture Radar (PALSAR) sensor on board of the Japanese Advanced Land Observation Satellite (ALOS) from October 2008 to January 2011. For the smaller lake, Laguna del Limon, we found a seasonal variation of 10-15 centimeters. This result was confirmed using two different satellite paths. For Lake Enriquillo we found a net decrease of about 20 centimeters in the water level from September 2009 to January 2011. This result agrees with an independent estimation based on lake hydrodynamics model predictions. In addition, our InSAR-based time series of lake level fluctuations revealed distinct behaviors of the two wetlands. For the Lake Enriquillo we found a continuous decrease in the water level throughout 2010 with a brief increase of the water level during the summer months, while for Laguna del Limon during the summer months the water level

  7. Study of the 6 August 2007 Crandall Canyon mine (Utah, USA) collapse from ALOS PALSAR InSAR (United States)

    Lu, Z.; Wicks, C.


    We use Advanced Land Observing Satellite (ALOS) Phased Array type L-band Synthetic Aperture Radar (PALSAR) interferometric synthetic aperture radar (InSAR) images to study land surface deformation over the Crandall Canyon mine in Utah, which collapsed on 6 August 2007 and killed 6 miners and 3 rescuers. The collapse was coincident to a local magnitude 3.9 earthquake. An InSAR image that spans the collapse shows subsidence of 20-25 cm over the Crandall Canyon mine. InSAR observation of the ground surface deformation over the Crandall Canyon mine has determined the location of the collapsed mine, suggested the mislocation for the 6 August 2007 earthquake from the standard epicenter relocation method, and estimated the extent of the collapsed area. These results complement the seismic investigation of the 6 August 2007 earthquake. Furthermore, modeling the ground surface deformation requires a significant amount of fault slip in addition to the volumetric compression.

  8. Application of InSAR and Gravimetry for Land Subsidence Hazard Zoning in Aguascalientes, Mexico

    Directory of Open Access Journals (Sweden)

    Jesús Pacheco-Martínez


    Full Text Available In this work we present an application of InSAR and gravimetric surveys for risk management related to land subsidence and surface ground faulting generation. A subsidence velocity map derived from the 2007–2011 ALOS SAR imagery and a sediment thicknesses map obtained from the inversion of gravimetric data were integrated with a surface fault map to produce a subsidence hazard zoning in the city of Aguascalientes, Mexico. The resulting zoning is presented together with specific recommendations about geotechnical studies needed for further evaluation of surface faulting in these hazard zones. The derived zoning map consists in four zones including null hazard (stable terrain without subsidence, low hazard (areas prone to subsidence, medium hazard (zones with subsidence and high hazard (zones with surface faulting. InSAR results displayed subsidence LOS velocities up to 10 cm/year and two subsidence areas unknown before this study. Gravimetric results revealed that the thicker sediment sequence is located toward north of Aguascalientes City reaching up to 600 m in thickness, which correspond to a high subsidence LOS velocity zone (up to 6 cm/year.

  9. InSAR measurements around active faults: creeping Philippine Fault and un-creeping Alpine Fault (United States)

    Fukushima, Y.


    Recently, interferometric synthetic aperture radar (InSAR) time-series analyses have been frequently applied to measure the time-series of small and quasi-steady displacements in wide areas. Large efforts in the methodological developments have been made to pursue higher temporal and spatial resolutions by using frequently acquired SAR images and detecting more pixels that exhibit phase stability. While such a high resolution is indispensable for tracking displacements of man-made and other small-scale structures, it is not necessarily needed and can be unnecessarily computer-intensive for measuring the crustal deformation associated with active faults and volcanic activities. I apply a simple and efficient method to measure the deformation around the Alpine Fault in the South Island of New Zealand, and the Philippine Fault in the Leyte Island. I use a small-baseline subset (SBAS) analysis approach (Berardino, et al., 2002). Generally, the more we average the pixel values, the more coherent the signals are. Considering that, for the deformation around active faults, the spatial resolution can be as coarse as a few hundred meters, we can severely 'multi-look' the interferograms. The two applied cases in this study benefited from this approach; I could obtain the mean velocity maps on practically the entire area without discarding decorrelated areas. The signals could have been only partially obtained by standard persistent scatterer or single-look small-baseline approaches that are much more computer-intensive. In order to further increase the signal detection capability, it is sometimes effective to introduce a processing algorithm adapted to the signal of interest. In an InSAR time-series processing, one usually needs to set the reference point because interferograms are all relative measurements. It is difficult, however, to fix the reference point when one aims to measure long-wavelength deformation signals that span the whole analysis area. This problem can be

  10. Software Toolbox Development for Rapid Earthquake Source Optimisation Combining InSAR Data and Seismic Waveforms (United States)

    Isken, Marius P.; Sudhaus, Henriette; Heimann, Sebastian; Steinberg, Andreas; Bathke, Hannes M.


    We present a modular open-source software framework (pyrocko, kite, grond; for rapid InSAR data post-processing and modelling of tectonic and volcanic displacement fields derived from satellite data. Our aim is to ease and streamline the joint optimisation of earthquake observations from InSAR and GPS data together with seismological waveforms for an improved estimation of the ruptures' parameters. Through this approach we can provide finite models of earthquake ruptures and therefore contribute to a timely and better understanding of earthquake kinematics. The new kite module enables a fast processing of unwrapped InSAR scenes for source modelling: the spatial sub-sampling and data error/noise estimation for the interferogram is evaluated automatically and interactively. The rupture's near-field surface displacement data are then combined with seismic far-field waveforms and jointly modelled using the framwork, which allows for fast forward modelling based on pre-calculated elastodynamic and elastostatic Green's functions. Lastly the grond module supplies a bootstrap-based probabilistic (Monte Carlo) joint optimisation to estimate the parameters and uncertainties of a finite-source earthquake rupture model. We describe the developed and applied methods as an effort to establish a semi-automatic processing and modelling chain. The framework is applied to Sentinel-1 data from the 2016 Central Italy earthquake sequence, where we present the earthquake mechanism and rupture model from which we derive regions of increased coulomb stress. The open source software framework is developed at GFZ Potsdam and at the University of Kiel, Germany, it is written in Python and C programming languages. The toolbox architecture is modular and independent, and can be utilized flexibly for a variety of geophysical problems. This work is conducted within the BridGeS project ( funded by the German Research Foundation DFG

  11. Identification and Characterization of Dynamic Alpine Subglacial Lakes Using a Fusion of InSAR and GIS (United States)

    Capps, D. L.; Rabus, B. T.; Clague, J. J.


    We use interferometric synthetic aperture radar (InSAR) and a geographic information system (GIS) to identify and characterize three dynamic alpine subglacial lakes in Glacier Bay National Park, Alaska. Subglacial and subaerial glacier-dammed lakes and the catastrophic floods (jokulhlaups) they release are a hazard in glacierized mountain regions around the world. Many subglacial lakes are not identified until they become subaerially exposed or release a jokulhlaup. The lakes discussed here are dammed by the Brady Glacier in southeast Alaska, 120 km west of Juneau. For InSAR analysis, we utilized 20 ascending and descending ERS-1/-2 tandem radar images (1-day repeat interval) provided by the European Space Agency and a Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM). We processed SAR data into unwrapped interferograms using standard techniques. Two interferograms have very poor coherence and the remaining eight show significant line of sight (LOS) displacement over the surface of the subglacial lakes through time. However, because the displacement is LOS, the relative contributions of horizontal and vertical displacement are ambiguous. We then created horizontal and vertical displacement maps using near concurrent ascending and descending track interferograms and a glacier flow map, which describes horizontal glacier movement. We created the flow map manually by drawing arrows in a GIS in the direction of glacier flow based on observed crevasse patterns, medial moraines, and constraining topography, then interpolated between arrows. The displacement maps have significant areas of error caused by suboptimal imaging geometry that we masked out using a simple script. Horizontal displacement over the subglacial lakes was negligible. We exported the resulting vertical displacement maps to a GIS and quantified the change in volume of the lakes through time. Because there was negligible horizontal displacement around the three lakes, we were able to

  12. Implementing the HDF-EOS5 software library for data products in the UNAVCO InSAR archive (United States)

    Baker, Scott; Meertens, Charles; Crosby, Christopher


    UNAVCO is a non-profit university-governed consortium that operates the U.S. National Science Foundation (NSF) Geodesy Advancing Geosciences and EarthScope (GAGE) facility and provides operational support to the Western North America InSAR Consortium (WInSAR). The seamless synthetic aperture radar archive (SSARA) is a seamless distributed access system for SAR data and higher-level data products. Under the NASA-funded SSARA project, a user-contributed InSAR archive for interferograms, time series, and other derived data products was developed at UNAVCO. The InSAR archive development has led to the adoption of the HDF-EOS5 data model, file format, and library. The HDF-EOS software library was designed to support NASA Earth Observation System (EOS) science data products and provides data structures for radar geometry (Swath) and geocoded (Grid) data based on the HDF5 data model and file format provided by the HDF Group. HDF-EOS5 inherits the benefits of HDF5 (open-source software support, internal compression, portability, support for structural data, self-describing file metadata enhanced performance, and xml support) and provides a way to standardize InSAR data products. Instrument- and datatype-independent services, such as subsetting, can be applied to files across a wide variety of data products through the same library interface. The library allows integration with GIS software packages such as ArcGIS and GDAL, conversion to other data formats like NetCDF and GeoTIFF, and is extensible with new data structures to support future requirements. UNAVCO maintains a GitHub repository that provides example software for creating data products from popular InSAR processing software packages like GMT5SAR and ISCE as well as examples for reading and converting the data products into other formats. Digital object identifiers (DOI) have been incorporated into the InSAR archive allowing users to assign a permanent location for their processed result and easily reference the

  13. Remarkable Urban Uplift in Staufen im Breisgau, Germany: Observations from TerraSAR-X InSAR and Leveling from 2008 to 2011

    Directory of Open Access Journals (Sweden)

    Hermann Kaufmann


    Full Text Available As geothermal energy is of increasing importance as a renewable energy source, there is a high demand for comprehensive studies to prevent failure during implementation, as is the case in Staufen im Breisgau, Germany. The drilling of seven wells for the geothermal heating of the city hall in 2007 is thought to have disturbed the existing hydro-geological system in the complex structured transition zone of the Upper Rhine Graben and the Schwarzwald massif. This event has led to uplift, related to the transformation of anhydrite to gypsum, which affects the infrastructure of the city centre via the generation of large cracks. This study focuses on the application of the InSAR Small Baseline Subset (SBAS approach using 50 X-band radar images from the German TerraSAR-X satellite (TSX to map the spatial and temporal patterns of the deformation field in detail. X-band InSAR time series analysis for the three-year time period from July 2008 through May 2011 indicates maximum velocities of ~12 cm/yr in the line of sight (LOS direction, from the ground to the satellite, approximately 50 m northeast of the drilling field. In comparison with leveling data for the same time period, TSX data analysis better delineates the border of the deformation area, and it is able to map the amount of deformation associated with different parts of the city. Moreover, this comparison indicates contributions of horizontal motion, as is expected for uplift patterns.

  14. Sparsity-driven tomographic reconstruction of atmospheric water vapor using GNSS and InSAR observations (United States)

    Heublein, Marion; Alshawaf, Fadwa; Zhu, Xiao Xiang; Hinz, Stefan


    An accurate knowledge of the 3D distribution of water vapor in the atmosphere is a key element for weather forecasting and climate research. On the other hand, as water vapor causes a delay in the microwave signal propagation within the atmosphere, a precise determination of water vapor is required for accurate positioning and deformation monitoring using Global Navigation Satellite Systems (GNSS) and Interferometric Synthetic Aperture Radar (InSAR). However, due to its high variability in time and space, the atmospheric water vapor distribution is difficult to model. Since GNSS meteorology was introduced about twenty years ago, it has increasingly been used as a geodetic technique to generate maps of 2D Precipitable Water Vapor (PWV). Moreover, several approaches for 3D tomographic water vapor reconstruction from GNSS-based estimates using the simple least squares adjustment were presented. In this poster, we present an innovative and sophisticated Compressive Sensing (CS) concept for sparsity-driven tomographic reconstruction of 3D atmospheric wet refractivity fields using data from GNSS and InSAR. The 2D zenith wet delay (ZWD) estimates are obtained by a combination of point-wise estimates of the wet delay using GNSS observations and partial InSAR wet delay maps. These ZWD estimates are aggregated to derive realistic wet delay input data of 100 points as if corresponding to 100 GNSS sites within an area of 100 km × 100 km in the test region of the Upper Rhine Graben. The made-up ZWD values can be mapped into different elevation and azimuth angles. Using the Cosine transform, a sparse representation of the wet refractivity field is obtained. In contrast to existing tomographic approaches, we exploit sparsity as a prior for the regularization of the underdetermined inverse system. The new aspects of this work include both the combination of GNSS and InSAR data for water vapor tomography and the sophisticated CS estimation. The accuracy of the estimated 3D water

  15. InSAR Measurements of Flank Stability at Cumbre Vieja Volcano, La Palma (Spain) (United States)

    Holley, Rachel; Thomas, Adam; Li, Zhenhong; McGuire, Bill; Ziebart, Marek; Day, Simon


    It has been suggested that instability of the western flank of Cumbre Vieja volcano, on the island of La Palma (Canary Islands), could have the potential to result in a lateral collapse of the flank, which in turn could generate an Atlantic tsunami. InSAR measurements provide an excellent way to corroborate data from GPS and structural surveys to provide independent corroboration. This work will use maps of atmospheric phase delay to improve the accuracy of persistent scatterer interferometry results over the island, and integrate these measurements with new GPS data, to give a complete assessment of flank stability and allow better assessment of the risks posed by the volcano.

  16. Monitoring and inversion on land subsidence over mining area with InSAR technique (United States)

    Wang, Y.; Zhang, Q.; Zhao, C.; Lu, Zhiming; Ding, X.


    The Wulanmulun town, located in Inner Mongolia, is one of the main mining areas of Shendong Company such as Shangwan coal mine and Bulianta coal mine, which has been suffering serious mine collapse with the underground mine withdrawal. We use ALOS/PALSAR data to extract land deformation under these regions, in which Small Baseline Subsets (SBAS) method was applied. Then we compared InSAR results with the underground mining activities, and found high correlations between them. Lastly we applied Distributed Dislocation (Okada) model to invert the mine collapse mechanism. ?? 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

  17. Single-Network Wide-Area Persistent Scatterer Interferometry: Algorithms with Application to Sentinel-1 InSAR Data (United States)

    Goel, K.; Shau, R.; Adam, N.


    Advanced InSAR techniques, for example, Persistent Scatterer Interferometry (PSI), allow long term deformation time series analysis with millimeter accuracy. ESA's Sentinel-1 SAR mission employs the TOPS mode as the standard mode for acquiring InSAR data. It provides a continuous and large coverage at conventional resolution. The idea is to have a wide-area PSI for mapping countries and continents. Although PSI has been successfully demonstrated and validated in the past for various applications, there are some limitations for processing a large-scale dataset. First, PSI is most effective in urban areas which have a large number of stable scatterers. For large-scale PSI, even non-urban areas need to be processed; and this requires robust algorithms for scatterer selection, network construction and inversion, and atmospheric phase removal. Second, the computational load can be very high, due to which, the processing is usually divided into overlapping blocks and merged later. This can however lead to spatial error propagation. This paper presents algorithms which have been developed for a robust PSI reference network estimation, while mitigating error propagation. Instead of dividing the scene into overlapping blocks, a single network (i.e. arcs connecting the scatterers) is created for the full scene. The relative deformation and residual DEM are estimated for the arcs using the LAMBDA estimator. The relative measurements of the network are finally integrated via least-squares inversion. Here, the sparsity of the system of linear equations is exploited to deal with big data (e.g. 10,000,000 arcs for 500,000 scatterers is a typical configuration for Sentinel-1). A QR or LU parallelizable solver is used for fast inversion. Also, variances of the estimates are calculated using a selected parallel inversion method based on LDL decomposition. Demonstration of the algorithms for large-scale deformation monitoring is provided using available Sentinel-1 data for Germany.

  18. Sentinel-1 Constellation for nationwide deformation mapping with InSAR -- From science to operations (United States)

    Dehls, John; Larsen, Yngvar; Marinkovic, Petar


    For more than a decade, InSAR has been used in Norway study landslides and subsidence. Initial studies concentrated on understanding and validating the technique in various settings. During the last five years, however, we have moved towards using InSAR in operational settings. Of all the challenges we have faced, the largest has been regular access to SAR imagery. The Sentinel-1 constellation will bring a paradigm shift to the field with its operational characteristics: mission configuration, acquisition planning, and data distribution policy. For the first time, we will have nationwide acquisitions with an unprecedented temporal spacing. By the end of this year, we will have a sufficiently long time series of data to produce an initial version of a national deformation map. Within the ESA SEOM InSARap project, we have developed the necessary updates of interferometric processing tools necessary to handle the novel TOPS mode, and successfully demonstrated the performance of S1 InSAR in a number of scientific applications. However, to fully exploit the key advantages of the Sentinel-1 mission, we still face a number of scientific and operational challenges, due to the new and unique characteristics of the mission. Specifically, the large coverage and dense temporal sampling results in very large data sets with a vastly increased information content, which still needs new algorithmic development to extract. In the context of national mapping, optimal harmonization of deformation maps based on overlapping individual S1 stacks is the most prominent challenge. Urban areas in Norway face much the same problems as many other cities throughout the world; subsidence due to soil compaction and groundwater changes or excavation, and resulting damage to infrastructure. More unique to Norway is the threat to lives caused by large unstable rock slopes along the steep fjords. In the 20th century alone, catastrophic rock slope failures leading to tsunamis in fjords and large

  19. InSAR time-series constraints on inter-seismic strain accumulation and creep distribution along North Anatolian and Chaman Faults (United States)

    Havazli, E.; Fattahi, H.; Amelung, F.


    In many aspects, the San Andreas and the North Anatolian fault zones show many similarities. They are similarly right-lateral, strike-slip faults, at the same time, are transforms. However, they vary in the maximum amount of lateral displacement and show different topographic features. The maximum offset is nearly 300 km along the San Andreas Fault whereas it is approximately 85-90 km along the North Anatolian Fault. In recent years, interseismic crustal velocities and strains have been determined for North Anatolian Fault Zone through repeated measurements using the Global Positioning System and satellite radar interferometry. The Chaman Fault in Pakistan and Afghanistan is the only major fault along the western India-Eurasia plate boundary zone and probably accommodates the entire relative plate motion of 30-35 mm/yr. Recent GPS and InSAR studies on the Chaman fault yield slip rates of 18 × 1 mm/yr. The inconsistency in geologic, geodetic and seismic slip rates along the Chaman Fault need investigations to better understand the geodynamic responses of the Indo-Asia collision along its western boundary. We use InSAR time-series analysis using archived and new SAR imagery to constrain strain accumulation across the North Anatolian Fault and Chaman Faults. We expect a relative accuracy of InSAR measurements better than 1 mm/yr over 100 km, made possible by recent advances in flattening residual, orbital error and atmospheric correction strategies [Fattahi & Amelung, 2013]. After validation of the technique in Southern San Andreas Fault, using GPS observations, we apply the same InSAR time-series approach to constrain strain accumulation across the North Anatolian and Chaman Faults. We will use the InSAR data to establish the first-order fault properties of the Chaman and North Anatolian Faults (creep distribution, locking depth) using analytical two-dimensional elastic strain accumulation models along different transects across the faults. Our preliminary results

  20. Simultaneous Inversion of GPS and InSAR for Regional Kinematics and Transients (United States)

    McCaffrey, R.


    The growth of continuous GPS networks and acquisition of InSAR data require fully time-dependent methods for their tectonic analyses. We are working on developing the merger of the kinematic block-model approach with transient deformation with the aim of interpreting the entire geodetic time series. The steady linear motions of the GPS sites are estimated through parameters that describe the block motions (angular velocities) plus elastic strain rates from locked faults and anelastic strain rates from distributed deformation. Through the kinematic model, the steady site velocities have a high degree of spatial correlation. Transients such as earthquakes, after-slip, slow-slip events and volcanic sources are described by a small number of free parameters that are estimated by direct inversion of the position time series simultaneously with the kinematic model parameters. InSAR data are used as line-of-sight displacements between two times (acquisition dates) and are matched by the time-dependent deformation model. We utilize both continuous and survey-mode GPS time series. To date we have applied the method to Cascadia, New Zealand, Sumatra, Papua (Indonesia), Yellowstone (Payne et al., this meeting), and Japan (Ohzono et al., this meeting). In addition to the information we can gain about the kinematics and transients, the method has applications in event detection and outlier removal.

  1. Integrating ALOS-2 and Sentinel-1 InSAR data for systematic volcano deformation monitoring (United States)

    Hickey, James; Biggs, Juliet; Ebmeier, Susanna; Parker, Amy


    The recent launches of the Sentinel-1 and ALOS-2 satellites provide a wealth of new Interferometric Synthetic Aperture Radar (InSAR) data for Earth observation purposes. We exploit these data for volcano deformation monitoring with a particular focus on Latin America, which is nominated as a priority target area under the Committee on Earth Observation Satellites volcano pilot program. By conducting an integrated survey that employs both Sentinel-1 and ALOS-2 we are able to achieve previously unprecedented levels of spatial and temporal resolution and combat decorrelation arising from vegetation cover. Latin America is an ideal target region as it has a diversity of geographic volcano locations (e.g., dense rainforest to high-altitude deserts), as well as abundant and varied volcanic activity. The numerous local volcano observatories can also directly benefit from this additional InSAR data when integrating it alongside ground-based observations. To further facilitate this impact we are directing our data outputs to a global volcano deformation database in near-real-time to provide a first-order access point for observatory staff and research scientists in need of satellite-derived ground-deformation results. We will draw upon a selection of case studies within Latin America to demonstrate our approach and how it can enhance volcano monitoring and eruption forecasting efforts.

  2. InSAR derived horizontal subsidence gradient as a tool for hazard assessment in urban areas. (United States)

    Cabral-Cano, E.; Dixon, T.; Diaz-Molina, O.


    Mexico City's subsidence has been recognized for over a century, after the first well battery was drilled to supply water to the rapidly growing city at the end of the XIX century. Consequences of the subsidence process are costly but the economic consequences of subsidence in urban areas is hard to assess due to the fact that their costs are generally factored into yearly maintenance budgets rather than accounting for them as a unique natural disaster. It has thus become increasingly important to assess the extent and magnitude of damage due to ground subsidence in the Mexico City metropolitan area. Periodic InSAR and GPS measurements including data from an 8 site permanent GPS network in Mexico City has enabled us to derive an integrated composite displacement map for Mexico City. This image was used to calculate the horizontal subsidence gradient for areas smaller than 100x100m throughout the city by computing the observed displacement difference divided by the respective pixel to pixel horizontal distance and comparing similarly calculated values from all adjacent pixels in order to select the maximum gradient. Both empiric and analytical approaches can been used to correlate the potential for surface faulting in high horizontal subsidence gradient zones and show that the principal factor for constraining these areas can be successfully determined using a combined Differential InSAR and GPS approach. We present surface faulting risk maps for several cities in central Mexico derived from the horizontal subsidence gradient approach as an example of this technique.

  3. Relative Efficiency of ALS and InSAR for Biomass Estimation in a Tanzanian Rainforest

    Directory of Open Access Journals (Sweden)

    Endre Hofstad Hansen


    Full Text Available Forest inventories based on field sample surveys, supported by auxiliary remotely sensed data, have the potential to provide transparent and confident estimates of forest carbon stocks required in climate change mitigation schemes such as the REDD+ mechanism. The field plot size is of importance for the precision of carbon stock estimates, and better information of the relationship between plot size and precision can be useful in designing future inventories. Precision estimates of forest biomass estimates developed from 30 concentric field plots with sizes of 700, 900, …, 1900 m2, sampled in a Tanzanian rainforest, were assessed in a model-based inference framework. Remotely sensed data from airborne laser scanning (ALS and interferometric synthetic aperture radio detection and ranging (InSAR were used as auxiliary information. The findings indicate that larger field plots are relatively more efficient for inventories supported by remotely sensed ALS and InSAR data. A simulation showed that a pure field-based inventory would have to comprise 3.5–6.0 times as many observations for plot sizes of 700–1900 m2 to achieve the same precision as an inventory supported by ALS data.

  4. InSAR Monitoring of Surface Deformation in Alberta's Oil Sands (United States)

    Pearse, J.; Singhroy, V.; Li, J.; Samsonov, S. V.; Shipman, T.; Froese, C. R.


    Alberta's oil sands are among the world's largest deposits of crude oil, and more than 80% of it is too deep to mine, so unconventional in-situ methods are used for extraction. Most in situ extraction techniques, such as Steam-Assisted Gravity Drainage (SAGD), use steam injection to reduce the viscosity of the bitumen, allowing it to flow into wells to be pumped to the surface. As part of the oil sands safety and environmental monitoring program, the energy regulator uses satellite radar to monitor surface deformation associated with in-situ oil extraction. The dense vegetation and sparse infrastructure in the boreal forest of northern Alberta make InSAR monitoring a challenge; however, we have found that surface heave associated with steam injection can be detected using traditional differential InSAR. Infrastructure and installed corner reflectors also allow us to use persistent scatterer methods to obtain time histories of deformation at individual sites. We have collected and processed several tracks of RADARSAT-2 data over a broad area of the oil sands, and have detected surface deformation signals of approximately 2-3 cm per year, with time series that correlate strongly with monthly SAGD steam injection volumes.

  5. Sensitivity of earthquake source inversions to atmospheric noise and corrections of InSAR data (United States)

    Scott, Chelsea Phipps; Lohman, Rowena Benfer


    Tropospheric phase delays pose a major challenge to InSAR (interferometric synthetic aperture radar)-based studies of tectonic deformation. One approach to the mitigation of effects from tropospheric noise is the application of elevation-dependent corrections based on empirical fits between elevation and interferometric phase. We quantify the effects of corrections with a range of complexity on inferred earthquake source parameters using synthetic interferograms with known atmospheric characteristics. We infer statistical properties of the stratified component of the atmosphere using pressure, temperature, and water vapor data from the North America Regional Reanalysis model over our region of interest in the Basin and Range province of the western United States. The statistics of the simulated atmospheric turbulence are estimated from InSAR and Global Positioning System data. We demonstrate potentially significant improvements in the precision of earthquake magnitude, depth, and dip estimates for several synthetic earthquake focal mechanisms following a correction for spatially variable atmospheric characteristics, relative to cases where the correction is based on a uniform delay versus elevation relationship or where no correction is applied. We apply our approach to the 1992 M5.6 Little Skull Mountain, Nevada, earthquake and demonstrate that the earthquake source parameter error bounds decrease in size after applying the atmospheric corrections. Our approach for evaluating the impact of atmospheric noise on inferred fault parameters is easily adaptable to other regions and source mechanisms.

  6. Volcano-tectonic deformation in the Kivu Region, Central Africa: Results from multi-year InSAR time series analysis and continuous GNSS observations of the Kivu Geodetic Network (KivuGNet) (United States)

    Geirsson, Halldor; D'Oreye, Nicolas; Smets, Benoît; Nobile, Adriano; Samsonov, Sergey; De Rauw, Dominique; Mashagiro, Niche; Kervyn, Francois


    The Kivu Region in Central Africa is a topographic dome cut by the depression of the western branch of the East African Rift, where the Nubia plate and the Victoria micro-plate are diverging by approximately 2-3 mm/yr (Stamps et al. 2008). Two closely spaced and frequently active volcanoes, Nyiragongo and Nyamulagira, are located at the plate boundary. Here, deformation signals from transient deformation events (i.e. earthquakes, eruptions, rifting episodes, intrusions or other subsurface mass movements) are intertwined with the more perpetual nature of inter-seismic strain accumulation and gradual magma accumulation. Here, we present deformation results from six years of operation of the 15- station KivuGNet (Kivu Geodetic Network) in the Kivu Region and multi-year InSAR time series of the region using the MSBAS approach (Samsonov & d'Oreye, 2012). Since 2009, KivuGNet has captured transient deformation from a) the 2010 eruption of Nyamulagira, b) the 2011-2012 eruption of Nyamulagira c) the Mw5.8 August 7, 2015 Katana earthquake at the western border of Lake Kivu. Importantly, the GPS data also show an ongoing deformation signal, which is most readily explained by long-term magma accumulation under the volcanic region. We use the GPS and InSAR deformation signals to constrain and compare source parameters of simplistic elastic models for the different time periods. Although not well constrained, most of the time periods indicate the presence of a deep (~15-30 km) magmatic source centered approximately under Nyamulagira or to the southeast of Nyamulagira, that inflates between eruptions and deflates during eruptions.

  7. On the Design of Radar Corner Reflectors for Deformation Monitoring in Multi-Frequency InSAR


    Garthwaite, Matthew C.


    Trihedral corner reflectors are being increasingly used as point targets in deformation monitoring studies using interferometric synthetic aperture radar (InSAR) techniques. The frequency and size dependence of the corner reflector Radar Cross Section (RCS) means that no single design can perform equally in all the possible imaging modes and radar frequencies available on the currently orbiting Synthetic Aperture Radar (SAR) satellites. Therefore, either a corner reflector design tailored to ...

  8. Volcano deformation source parameters estimated from InSAR: Sensitivities to uncertainties in seismic tomography (United States)

    Masterlark, Timothy; Donovan, Theodore; Feigl, Kurt L.; Haney, Matthew; Thurber, Clifford H.; Tung, Sui


    The eruption cycle of a volcano is controlled in part by the upward migration of magma. The characteristics of the magma flux produce a deformation signature at the Earth's surface. Inverse analyses use geodetic data to estimate strategic controlling parameters that describe the position and pressurization of a magma chamber at depth. The specific distribution of material properties controls how observed surface deformation translates to source parameter estimates. Seismic tomography models describe the spatial distributions of material properties that are necessary for accurate models of volcano deformation. This study investigates how uncertainties in seismic tomography models propagate into variations in the estimates of volcano deformation source parameters inverted from geodetic data. We conduct finite element model-based nonlinear inverse analyses of interferometric synthetic aperture radar (InSAR) data for Okmok volcano, Alaska, as an example. We then analyze the estimated parameters and their uncertainties to characterize the magma chamber. Analyses are performed separately for models simulating a pressurized chamber embedded in a homogeneous domain as well as for a domain having a heterogeneous distribution of material properties according to seismic tomography. The estimated depth of the source is sensitive to the distribution of material properties. The estimated depths for the homogeneous and heterogeneous domains are 2666 ± 42 and 3527 ± 56 m below mean sea level, respectively (99% confidence). A Monte Carlo analysis indicates that uncertainties of the seismic tomography cannot account for this discrepancy at the 99% confidence level. Accounting for the spatial distribution of elastic properties according to seismic tomography significantly improves the fit of the deformation model predictions and significantly influences estimates for parameters that describe the location of a pressurized magma chamber.

  9. Larsen C Ice Shelf rheology inferred by combining InSAR observations and numerical modeling (United States)

    Khazendar, A.; Rignot, E. J.; Larour, E. Y.


    Larsen C Ice Shelf presents a valuable setting for investigating the many connected processes involved in the evolution of ice shelves in a warming climate. The stability of this ice shelf has become a topic of keen interest, especially following the disintegration of Larsen B and other Peninsular ice shelves, and the consequent increase in continental ice flow to the ocean. We are addressing this complex question in a multi-disciplinary manner by combining remote sensing and numerical modeling. Thus, we analyzed satellite InSAR observations of Larsen C obtained in the years 2000 and 2007 which revealed that ice shelf flow velocity in some areas have had some changes. We then applied inverse modeling, combining the observed velocity field with numerical flow models, to infer a spatial distribution of the flow parameter for the ice shelf, which is indispensable for accurately modeling ice shelf flow and evolution. The inferred rheology field allowed us to detect zones of weakness, including a large area in the middle of the ice shelf, many of which are associated with fracture features. Our similar previous analysis of Larsen B at the eve of its disintegration in 2002 emphasizes the significant interaction and interdependence among frontal calving, flow acceleration, variable rheology including fracture zones, and the ultimate destabilization of the ice shelf. Therefore, this work, by measuring any recent acceleration in the flow of Larsen C and inferring its rheology provides essential tools to evaluate its stability and long-term prospects. This work was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration, Cryospheric Sciences Program.

  10. Recent Ground Deformation around the Northern Part of Lake Nasser, Aswan, Egypt Using GPS and InSAR (United States)

    Saleh, Mohamed; Masson, Frederic


    The rate of seismic activity around the Lake Nasser was rapidly increased after the creation of the High Dam. The largest earthquake recorded in this area was the November 14, 1981, with magnitude ML5.6 at Kalabsha fault, 60 km southwest of Aswan High Dam. Due to the great importance of this region, many attempts were made to constrain the ground deformation around the northern part of Nasser Lake using GPS data. Due to the sparse spatial resolution of the GPS stations in this region, the achieved results need more verification. Therefore, we are using about 15 years of campaign data collected from the local geodetic network around the northern part of the Lake in addition to 34 SAR scenes, covering the time span from 2002 to 2010, to better constrain the ground deformation of this area. The processing of the GPS data was carried out using GAMIT/GLOBK whereas, the NSBAS technique was applied to the SAR scenes. Combining the results from both GPS and InSAR analysis may help to better understand the geodynamical behavior of such an important region in Egypt for the safety of human and vital national constructions.

  11. Allan variance computed in space domain: Application to InSAR data to characterize noise and geophysical signal

    CERN Document Server

    Cavalié, Olivier


    The Allan variance was introduced fifty years ago for analyzing the stability of frequency standards. Beside its metrological interest, it is also an estimator of the large trends of the power spectral density (PSD) of frequency deviation. For instance, the Allan variance is able to discriminate different types of noise characterized by different power laws in the PSD. But, it was also used in other fields: accelerometry, geophysics, geodesy, astrophysics and even finances! However, it seems that up to now, it has been exclusively applied for time series analysis. We propose here to use the Allan variance onto spatial data. Interferometric synthetic aperture radar (InSAR) is used in geophysics to image ground displacements in space (over the SAR image spatial coverage) and in time thank to the regular SAR image acquisitions by dedicated satellites. The main limitation of the technique is the atmospheric disturbances that affect the radar signal while traveling from the sensor to the ground and back. In this p...

  12. 基于InSAR技术的DEM提取及InSAR DEM精度与地形因子的关系%DEM Extraction Based on InSAR Technology and Relationship between InSAR DEM Accuracy and Terrain Factor

    Institute of Scientific and Technical Information of China (English)

    张博; 张文君; 蔡国琳


    为研究基于InSAR技术DEM精度以及与地形因子的关系,以巴姆地区ENVISAT卫星SAR影像作为试验数据.利用InSAR技术提取DEM,研究InSAR DEM与SRTM-3 DEM精度关系,同时重点研究InSAR DEM的精度与地形因子关系特征.结果表明,研究区域InSAR DEM与SRTM-3 DEM高程差异的中误差为12.50 m,并且精度与地形因子密切相关.%In order to study DEM accuracy based on InSAR technology and relationship with terrain factor,with ENVTSAT satellite SAR images in Bam City as an example,DEM was generated by using InSAR technology,and the relationship between InSAR DEM and SRTM-3 DEM was studied,and also focused on study relationship characteristics between InSAR DEM accuracy and terrain factor. The results showed that the elevation difference error of the test zone in InSAR DEM and SRTM-3 DEM is 12.50 m,its accuracy is related to terrain factor.

  13. Investigation on Mining Subsidence Based on Multi-Temporal InSAR and Time-Series Analysis of the Small Baseline Subset—Case Study of Working Faces 22201-1/2 in Bu’ertai Mine, Shendong Coalfield, China

    Directory of Open Access Journals (Sweden)

    Chao Ma


    Full Text Available High-intensity coal mining (large mining height, shallow mining depth, and rapid advancing frequently causes large-scale ground damage within a short period of time. Understanding mining subsidence under high-intensity mining can provide a basis for mining-induced damage assessment, land remediation in a subsidence area, and ecological reconstruction in vulnerable ecological regions in Western China. In this study, the mining subsidence status of Shendong Coalfield was investigated and analyzed using two-pass differential interferometric synthetic aperture radar (DInSAR technology based on high-resolution synthetic aperture radar data (RADARSAT-2 precise orbit, multilook fine, 5 m collected from 20 January 2012 to June 2013. Surface damages in Shendong Coalfield over a period of 504 days under open-pit mining and underground mining were observed. Ground deformation of the high-intensity mining working faces 22201-1/2 in Bu’ertai Mine, Shendong Coalfield was monitored using small baseline subset (SBAS InSAR technology. (1 DInSAR detected and located 85 ground deformation areas (including ground deformations associated with past-mining activity. The extent of subsidence in Shendong Coalfield presented a progressive increase at an average monthly rate of 13.09 km2 from the initial 54.98 km2 to 225.20 km2, approximately, which accounted for 7% of the total area of Shendong Coalfield; (2 SBAS-InSAR reported that the maximum cumulative subsidence area reached 5.58 km2 above the working faces 22201-1/2. The advance speed of ground destruction (7.9 m/day was nearly equal to that of underground mining (8.1 m/day.

  14. Adaptive InSAR combined with surveying techniques for an improved characterisation of active landslides (El Portalet) (United States)

    Duro, Javier; Albiol, David; Sánchez, Francisco; Herrera, Gerardo; García Davalillo, Juan Carlos; Fernandez Merodo, Jose Antonio; Allasia, Paolo; Lollino, Piernicola; Manconi, Andrea


    InSAR and the Persistent Scatterer Interferometry (PSI) are well established techniques for monitoring urban and rural areas. Besides the large number of available SAR data in the past, the current and forthcoming space-borne SAR sensors offer the possibility of selecting the optimal acquisition configuration (wavelength, resolution, incidence angle, etc.) for each application. However, optimal data takes are not always possible and/or the processing area is difficult to analyse under an InSAR point of view. In such situations, additional and adaptive InSAR developments combined with other surveying techniques provide consistent solutions that meet the requirements of different application cases This work presents an advanced InSAR processing adapted for an active slow deformation landslide in a mountainous area. The presentation will show the benefits of applying advanced and adaptive filtering strategies for improving the InSAR quality in highly decorrelated environments. The availability of Artificial Corner Reflectors over the area of interest enables to tune the filtering procedure and thus maximize the detection and exploitation of natural targets (bare soil, roads, rocks) as measurement points while preserving the phase characteristics over individual and punctual targets (building corners, poles). The new results will be evaluated in terms of final density and quality of measurement points that can be retrieved. The results will show that a very high density of measurements improves the detection of the deformation gradients and its perimeters resulting in a more accurate characterization of the landslide area. The area of study is El Portalet, an active slow deformation landslide area in Central Spanish Pyrenees. During many years the slope of interest has been monitored with several surveying techniques like DGPS, extensometers, inclinometers, GB-SAR and InSAR jointly with an extensive geological interpretation. Currently, in the frame of the FP7 Project

  15. Stochastic geometrical model and Monte Carlo optimization methods for building reconstruction from InSAR data (United States)

    Zhang, Yue; Sun, Xian; Thiele, Antje; Hinz, Stefan


    Synthetic aperture radar (SAR) systems, such as TanDEM-X, TerraSAR-X and Cosmo-SkyMed, acquire imagery with high spatial resolution (HR), making it possible to observe objects in urban areas with high detail. In this paper, we propose a new top-down framework for three-dimensional (3D) building reconstruction from HR interferometric SAR (InSAR) data. Unlike most methods proposed before, we adopt a generative model and utilize the reconstruction process by maximizing a posteriori estimation (MAP) through Monte Carlo methods. The reason for this strategy refers to the fact that the noisiness of SAR images calls for a thorough prior model to better cope with the inherent amplitude and phase fluctuations. In the reconstruction process, according to the radar configuration and the building geometry, a 3D building hypothesis is mapped to the SAR image plane and decomposed to feature regions such as layover, corner line, and shadow. Then, the statistical properties of intensity, interferometric phase and coherence of each region are explored respectively, and are included as region terms. Roofs are not directly considered as they are mixed with wall into layover area in most cases. When estimating the similarity between the building hypothesis and the real data, the prior, the region term, together with the edge term related to the contours of layover and corner line, are taken into consideration. In the optimization step, in order to achieve convergent reconstruction outputs and get rid of local extrema, special transition kernels are designed. The proposed framework is evaluated on the TanDEM-X dataset and performs well for buildings reconstruction.

  16. InSAR time-series investigation of long-term ground displacement at Beijing Capital International Airport, China (United States)

    Gao, Mingliang; Gong, Huili; Chen, Beibei; Zhou, Chaofan; Chen, Wenfeng; Liang, Yue; Shi, Min; Si, Yuan


    Interferometric synthetic aperture radar (InSAR) time-series analysis provides high spatial resolution and continuous temporal coverage for investigations of long-term ground displacement. Beijing, the capital city of China, has suffered from land subsidence since the 1950s, and extreme groundwater extraction has led to subsidence rates of > 100 mm/year. In this study, InSAR time-series analysis is performed on different data subsets to investigate the ground displacement at Capital International Airport, Beijing, between June 2003 and November 2013. The results show that the ground surface in the airport has deformed at different rates ranging from - 66.2 mm/year (sinking) to 8.2 mm/year (uplift) relative to the reference point. The projected vertical displacement rates agreed with measurements estimated from ground-leveling surveys, and the correlation coefficient of the fitting result is 0.96, with a standard deviation of 0.9 mm/year and a mean different of 2.0 mm/year. The runways and terminals have been affected by land subsidence to various degrees. Previous studies has indicated that long-term intense groundwater extraction is the main reason leading to land subsidence in this area. Other triggering factors, such as active faults, the quaternary compressible layers and urbanization, also have different degrees of contribution or impact on land subsidence in Beijing Plain. Furthermore, some interesting behaviors from groundwater (such as inter- and semi-annual variations) and subsidence, the relationship between them are also found in this study.

  17. Fault and anthropogenic processes in central California constrained by satellite and airborne InSAR and in-situ observations (United States)

    Liu, Zhen; Lundgren, Paul


    The San Andreas Fault (SAF) system is the primary plate boundary in California, with the central SAF (CSAF) lying adjacent to the San Joaquin Valley (SJV), a vast structural trough that accounts for about one-sixth of the United Sates' irrigated land and one-fifth of its extracted groundwater. The CSAF displays a range of fault slip behavior with creeping in its central segment that decreases towards its northwest and southeast ends, where the fault transitions to being fully locked. At least six Mw ~6.0 events since 1857 have occurred near the Parkfield transition, most recently in 2004. Large earthquakes also occurred on secondary faults parallel to the SAF, the result of distributed deformation across the plate boundary zone. Recent studies have revealed the complex interaction between anthropogenic related groundwater depletion and the seismic activity on adjacent faults through stress interaction. Despite recent progress, many questions regarding fault and anthropogenic processes in the region still remain. For example, how is the relative plate motion accommodated between the CSAF and off-fault deformation? What is the distribution of fault creep and slip deficit at shallow depths? What are the spatiotemporal variations of fault slip? What are the spatiotemporal characteristics of anthropogenic and lithospheric processes and how do they interact with each other? To address these, we combine satellite InSAR and NASA airborne UAVSAR data to image on and off-fault deformation. The UAVSAR data cover fault perpendicular swaths imaged from opposing look directions and fault parallel swaths since 2009. The much finer spatial resolution and optimized viewing geometry provide important constraints on near fault deformation and fault slip at very shallow depth. We performed a synoptic InSAR time series analysis using ERS-1/2, Envisat, ALOS and UAVSAR interferograms. The combined C-band ERS-1/2 and Envisat data provide a long time interval of SAR data over the region

  18. Location and Source Characteristics of the January 6, 2016 North Korean Nuclear Test Constrained by InSAR (United States)

    Wei, Meng


    The interferometric synthetic aperture radar (InSAR) data from the JAXA ALOS-2 satellite show possible deformation associated with the January 6, 2016 North Korean nuclear test whereas the ESA Sentinel-1A data are decorrelated. This is the first time that deformation related to a nuclear test has been measured since 1992. Here, I present two interpretations of the observed deformation: First, the deformation can be explained by a triggered landslide on the western slope of Mt. Mantap, with a displacement of up to 10 cm across a patch of 1 km2. Second, the observation may be from uplift created by the nuclear explosion. In the second interpretation, the location, depth, and cavity size can be estimated from a topography-corrected homogenous half-space model (Mogi). The preferred location of the January 6, 2016 event is 41.2993°N 129.0715°E, with an uncertainty of 100 m. The estimated depth is 420-700 m, and the cavity radius is 23-27 m. Based on empirical data and the assumption of granite as the host rock, the yield is estimated to be 11.6-24.4 kilotons of TNT, which is consistent with previous results based on seismic data. With these two interpretations, I demonstrate that InSAR data provide an independent tool to locate and estimate source characteristics of nuclear tests in North Korea. The ambiguity of interpretation is mainly due to the limited InSAR data acquisition. Future frequent data collection by current and upcoming InSAR satellites will allow full use of InSAR for nuclear monitoring and characterization in North Korea and around the world.

  19. Repeat-pass InSAR processing for Vegetation Height Calculation: Theory and a validated example (United States)

    Siqueira, P.; Lei, Y.


    Knowledge of the vegetation height for a forested region is often used as a proxy for stem volume, biomass, and for characterizing habitats of a variety of plant and animal species. For this reason, remote sensing measures available from stereography, lidar, and InSAR have been important tools for airborne and spaceborne platforms. Among these and other candidates for measuring vegetation heights, InSAR has the advantage of achieving wide coverage areas (on the order of 100 km in cross-track swath) over short time periods, thus making it practical for large-scale assessments of the global environment. The determination of forest stand height (FSH), which is an assessment made on the order of one to ten hectares of resolution, InSAR can provide measures that are proportional to FSH. These are: 1.) interferometric phase compared to a known DEM, preferably of the bald earth, 2.) interferometric correlation (polarimetric or otherwise), which is related to the volume scattering nature of the target, and 3.) interferometric correlation which is related to the temporal decorrelation of the target. Of these, while the volumetric aspect of interferometric correlation is of keen interest, because of the dominant error source of temporal decorrelation, it comes at the cost of the need to perform single-pass interferometry. While such satellite systems do exist (notably the TanDEM-X mission), for vegetation applications, lower frequency systems such as ALOS-1 and -2, and the future NASA radar mission at L-band, provides better signal returns from throughout the vegetation canopy. Hence, rather than relying on volumetric correlation to provide the desired FSH signature, repeat-pass observations of temporal decorrelation are coupled with a vegetation model for this decorrelation to determine the vegetation height. In order to demonstrate this technique, the University of Massachusetts has used 46-day repeat-pass ALOS data to estimate FSH over the US State of Maine, nearly a 10

  20. Interseismic coupling on the Hayward-Calaveras fault zone from InSAR (United States)

    Chaussard, E.; Burgmann, R.; Fattahi, H.; Johnson, C. W.; Nadeau, R. M.; Taira, T.; Johanson, I. A.


    Evaluation of interseismic deformation traditionally relies on GPS and alignment arrays (AA) providing precise but spatially sparse measurements. Here, we resolve with a high spatial resolution interseismic strain accumulation and fault creep associated with the Hayward and Calaveras Faults (HF and CF) in the Eastern San Francisco Bay Area using InSAR. The large 1992-2011 ascending and descending ERS-Envisat dataset enables characterization of short- and long-wavelength horizontal and vertical deformation as small as 2 mm/yr without alignment to a GPS-based model. A comparison between independent InSAR, GPS, and AA datasets shows that the remaining noise is negligible in mean velocity maps and that the creep rates are mostly constant between 1992-2011. Creep rates vary from 0±2 mm/yr on the northern CF to 14±2 mm/yr on the central CF south of the HF surface junction. The high spatial resolution velocity map also highlights the southernmost occurrence of creep on the HF, located ~15 km farther south than prior determinations based on AA and field mapping. We remove the long-wavelength deformation using a deep-dislocation model and estimate the shallow slip due to creep by inverting the remaining InSAR fault-parallel motion. We confirm a good agreement between our model and surface slip rates measured with AA and slip at depth from characteristically repeating earthquakes. The distribution of aseismic slip is comparable to previous models focused on the HF, confirming that the distribution of creeping and locked patches is stable. We find that the northern CF is mostly locked, explaining the absence of seismicity and that most of the aseismic slip is limited to the shallowest 5 km on the HF and CF, suggesting partial or full locking at deeper levels. Considering the time since the last earthquakes and the difference between the long-term slip rates and the shallow aseismic slip, we infer that a joint rupture of the HF and central CF could currently produce a M7.1

  1. Ionospheric Correction of InSAR for Accurate Ice Motion Mapping at High Latitudes (United States)

    Liao, H.; Meyer, F. J.


    Monitoring the motion of the large ice sheets is of great importance for determining ice mass balance and its contribution to sea level rise. Recently the first comprehensive ice motion of the Greenland and the Antarctica have been generated with InSAR. However, these studies have indicated that the performance of InSAR-based ice motion mapping is limited by the presence of the ionosphere. This is particularly true at high latitudes and for low-frequency SAR data. Filter-based and empirical methods (e.g., removing polynomials), which have often been used to mitigate ionospheric effects, are often ineffective in these areas due to the typically strong spatial variability of ionospheric phase delay in high latitudes and due to the risk of removing true deformation signals from the observations. In this study, we will first present an outline of our split-spectrum InSAR-based ionospheric correction approach and particularly highlight how our method improves upon published techniques, such as the multiple sub-band approach to boost estimation accuracy as well as advanced error correction and filtering algorithms. We applied our work flow to a large number of ionosphere-affected dataset over the large ice sheets to estimate the benefit of ionospheric correction on ice motion mapping accuracy. Appropriate test sites over Greenland and the Antarctic have been chosen through cooperation with authors (UW, Ian Joughin) of previous ice motion studies. To demonstrate the magnitude of ionospheric noise and to showcase the performance of ionospheric correction, we will show examples of ionospheric-affected InSAR data and our ionosphere corrected result for comparison in visual. We also compared the corrected phase data to known ice velocity fields quantitatively for the analyzed areas from experts in ice velocity mapping. From our studies we found that ionospheric correction significantly reduces biases in ice velocity estimates and boosts accuracy by a factor that depends on a

  2. Hydrothermal fluid flow models of Campi Flegrei caldera, Italy constrained by InSAR surface deformation time series observations (United States)

    Lundgren, P.; Lanari, R.; Manzo, M.; Sansosti, E.; Tizzani, P.; Hutnak, M.; Hurwitz, S.


    Campi Flegrei caldera, Italy, located along the Bay of Naples, has a long history of significant vertical deformation, with the most recent large uplift (>1.5m) occurring in 1983-1984. Each episode of uplift has been followed by a period of subsidence that decreases in rate with time and may be punctuated by brief episodes of lesser uplift. The large amplitude of the major uplifts that occur without volcanic activity, and the subsequent subsidence has been argued as evidence for hydrothermal amplification of any magmatic source. The later subsidence and its temporal decay have been argued as due to diffusion of the pressurized caldera fill material into the less porous surrounding country rock. We present satellite synthetic aperture radar (SAR) interferometry (InSAR) time series analysis of ERS and Envisat data from the European Space Agency, based on exploiting the Small Baseline Subset (SBAS) approach [Berardino et al., 2002]; this allows us to generate maps of relative surface deformation though time, beginning in 1992 through 2007, that are relevant to both ascending and descending satellite orbits. The general temporal behavior is one of subsidence punctuated by several lesser uplift episodes. The spatial pattern of deformation can be modeled through simple inflation/deflation sources in an elastic halfspace. Given the evidence to suggest that fluids may play a significant role in the temporal deformation of Campi Flegrei, rather than a purely magmatic or magma chamber-based interpretation, we model the temporal and spatial evolution of surface deformation as a hydrothermal fluid flow process. We use the TOUGH2-BIOT2 set of numerical codes [Preuss et al., 1999; Hsieh, 1996], which couple multi-phase (liquid-gas) and multi-component (H2O-CO2) fluid flow in a porous or fractured media with plane strain deformation and fluid flow in a linearly elastic porous medium. We explore parameters related to the depth and temporal history of fluid injection, fluid

  3. A new look at vertical motion around the San Andreas Fault in the Southern California from Integrated GPS and InSAR measurements (United States)

    Hammond, W. C.; Johnson, K. M.; Weldon, R. J.; Blewitt, G.; Burgette, R. J.


    Here we report on a new analysis of GPS and space-based InSAR-estimated vertical motions in the vicinity of the southern San Andreas Fault (SAF) near the eastern Transverse Ranges. We consider GPS data from all of the available high precision geodetic networks in southern California such as the EarthScope Plate Boundary Observatory and SCIGN networks. We analyze raw GPS observations using the GIPSY-OASIS software, and align the solutions to the newly updated NA12 reference frame, derived from ITRF2008. Vertical data are considered if the station has at least 4 years of data, have time series that are fit well by a linear plus seasonal terms plus steps from known equipment changes and earthquakes. We supplement the data with rates from time series analyses of ERS and ENVISAT radar data between 1992 and 2009, obtained from the WinSAR archive. We use 532 scenes from 7 track/frames to form 7476 interferograms, providing line-of-sight (LOS) velocities for overlapping descending (6) and ascending (1) frames. To separate the vertical from the horizontal signals, we align the InSAR LOS rates to the GPS LOS rates using a bilinear transformation and subtract the LOS signal of horizontal deformation estimated from a strain rate map constructed from horizontal GPS velocities. The result is an InSAR LOS rate map aligned to NA12, which we unproject into the vertical direction. InSAR and GPS motions track one another well, with RMS difference in vertical rate of 1.0 mm/yr, where the signal of vertical rate varies between -5.0 and 2.6 mm/yr. Aligning the InSAR to GPS reduces errors in InSAR attributable to long wavelength effects from the atmosphere and orbit uncertainties. The vertical rates show both basin-scale pockets of subsidence and regional wavelength variations in uplift rate. We detect previously reported signals in the San Bernadino, San Jacinto, Pomona, and LA basins with both the GPS and InSAR. Near the coast uplift patterns are similar to those from repeated leveling

  4. Decentralized adaptive sliding mode control for beam synchronization of tethered InSAR system (United States)

    Zhang, Jinxiu; Zhang, Zhigang; Wu, Baolin


    Beam synchronization problem of tethered interferometric synthetic aperture radar (InSAR) is addressed in this paper. Two antennas of the system are carried by separate satellites connected through a tether to obtain a preferable baseline. A Total Zero Doppler Steering (TZDS) is implemented to mother-satellite to cancel the residual Doppler. Subsequently attitude reference trajectories for the two satellites are generated to achieve the beam synchronization and TZDS. Thereafter, a decentralized adaptive sliding mode control law is proposed to track these reference trajectories in the presence of model uncertainties and external disturbances. Finally, the stability of closed-loop system is proved by the corollary of Barbalat's Lemma. Simulation results show the proposed control law is effective to achieve beam synchronization of the system.

  5. Block-like plate movements in eastern Anatolia observed by InSAR

    KAUST Repository

    Cavalie, Olivier


    The question whether continental plates deform internally or move as rigid blocks has been debated for several decades. To further address this question, we use large-scale interferometric synthetic aperture radar (InSAR) data sets to study how eastern Anatolia and its surrounding plates deform. We find that most of the deformation is focused at the North and East Anatolian faults and little intraplate deformation takes place. Anatolia is therefore moving, at least its eastern part, as a uniform block. We estimate the slip velocity and locking depth of the North Anatolian fault at this location to be 20 mm/yr and ~14 km, respectively. High deformation gradient found near the East Anatolian fault, on the other hand, suggests that little stress is accumulating along the eastern sections of that fault.

  6. 基于GPS和NCEP FNL数据改正InSAR大气延迟的可行性分析%Feasibility analysis of InSAR atmospheric delay correction based on GPS observations and NCEP FNL data

    Institute of Scientific and Technical Information of China (English)

    张书毕; 傅拓


    Over last two decades, Interferometric Synthetic Aperture Radar (InSAR) has been widely used to monitor geological hazards due to its high precision, wide area coverage and low cost. However, InSAR suffers from the phase delay in radio signal propagation through the atmosphere, and it becomes worse during the geological hazards which always occur in complex geological hilly areas with heavy rainfall. Based on a detailed review of some main application studies so far in the world, the advantages and difficulties concerning the application of these skills to landslide monitoring are concluded. By using some new developments of monitoring technique, possible solutions for the existing problems to practical application of InSAR atmospheric delay correction based on GPS observations and NCEP FNL data are proposed. This paper introduces the principles and data processing method of this technique, associates with some examples proving the advantages of reducing the residual of InSAR atmospheric delay phase, so as to improve monitoring accuracy.%InSAR技术是近二十几年来迅速发展的极具应用价值的空间对地观测新技术,它具有监测精度高、范围大、成本低、空间连续覆盖等优点,为滑坡、泥石流等地质灾害监测提供了一种新型的监测方法。但由于地质灾害多发生在暴雨频发、地质地貌复杂的区域,特殊的地理位置与气候使得InSAR技术应用中受大气延迟的影响非常严重,导致InSAR图像错误解释。本文在全面回顾当前主流的几种改正InSAR大气延迟的方法在国内外滑坡监测中的应用现状和实例的基础上,分析这几种技术的优势及问题点,并结合最新技术进展提出了一种基于GPS和NCEP FNL数据改正InSAR大气延迟的新方法,详细推导了该方法处理的流程,结合实例进行了分析比较,证明了其可有效削弱InSAR干涉图中的残余大气延迟相位,进而提高InSAR监测精度的优点。

  7. Surface subsidence induced by the Crandall Mine (Utah) collapse: InSAR observations and anelastic modeling (United States)

    Plattner, C.; Wdowinski, S.; Dixon, T. H.; Govers, R. M.


    The Crandall Mine collapsed in August 2007 and resulted in the death of 6 miners. The collapse induced surface subsidence visible by satellite geodesy. We processed data from ALOS satellite acquired before and after the collapse to quantify the subsidence and infer the deformation at depth. Our InSAR results show a localized oval shaped (1000 x 500 m2) pattern of subsidence with a maximum vertical displacement of 29 cm. Profiles across the subsided area show a steep V-shaped pattern. We first model the collapse using an elastic halfspace model. However, we find poor agreement between the elastic model solution and the InSAR observations, mainly because the elastic solution is characterized by a broad subsidence pattern, as elasticity does not explain localized strain. To overcome this limitation, we investigated analytical models that consider strain localization due to material failure. Here, we apply a model predicting surface settlement from tunneling (Loganathan and Poulos, 1998). This model uses the internal friction angle to define the maximum width of the subsidence area. To account for the flat shape of the collapse strata, we modify the model by changing its geometry from circular shape to elliptical (500 x 2.4 m). Our results show a very good fit in terms of the subsidence pattern, in particular the localization of the subsidence. We found that the surface subsidence was caused by a 7.7% collapse of the mine elliptical shaped mine. Although our simple model does not explain all the observed features, we find it more suitable than elastic halfspace models to explain the localized deformation pattern.

  8. Subsidence and associated shallow faulting hazard assessment in central Mexico using InSAR and GPS (United States)

    Cabral-Cano, E.; Solano Rojas, D. E.; Oliver-Cabrera, T.; Salazar-Tlaczani, L.; Wdowinski, S.; DeMets, C.; Pacheco, J.


    While subsidence has affected Mexico City for over a century, other cities in central Mexico have been subjected to subsidence since the '80, as a result of their large urban expansion, population increase and aggressive groundwater extraction rates. The continuous subsidence results in severe damage to urban infrastructure and civil structures. Unfortunately the damage cost assessment and vulnerability are difficult to evaluate, because of the variable geographic extent and the continuous nature of the process, which have different characteristics than localized, short duration hazards, as earthquakes or flood events.We have monitored land subsidence in 17 cities in central Mexico using both InSAR and GPS observations. InSAR provides an unsurpassed synoptic view of the earth's dynamic surface. However, different satellite sensors and sometimes widely spaced data availability make it difficult to derive long-term time series, rapid changes or nonlinear variations of subsidence velocities. To alleviate this situation, higher temporal resolution subsidence observations of associated fault motion has been pursued using continuously operating GPS stations. We have developed a GPS network that covers 6 urban centers to detect short duration variations using different processing schemes that include both real-time solutions using RTNet as well as daily solution using Gipsy-Oasis.Cartographic products based on these techniques have been merged with other population, hydrology and meteorology data sets. This approach allows a better hazard assessment and provides information for other purposes, such as vulnerability for shallow faulting, land use zonations, and other decision elements for water resource management agencies. We will provide examples of these hazard assessments for several cities, including Mexico City, Aguascalientes, Morelia, Irapuato and Celaya and the challenges encountered to integrate these results with other data sets from federal and state

  9. Possible coupling of Campi Flegrei and Vesuvius as revealed by InSAR time series, correlation analysis and time dependent modeling (United States)

    Walter, T. R.; Shirzaei, M.; Manconi, A.; Solaro, G.; Pepe, A.; Manzo, M.; Sansosti, E.


    Volcanoes are often considered as isolated systems, however, evidences increase that adjacent volcanoes are directly coupled or may be closely related to remote triggers. At the Italian volcanoes Campi Flegrei and Vesuvius, as well as adjacent volcano-tectonic systems, all located in the Campania Volcanic Province with ~ 2 million inhabitants, a new analysis of satellite radar data reveals allied deformation activity. Here we show that during the 16-year records from 1992 to 2008, identified episodes of deformation have occurred in correlation. Albeit differences in the quantity of deformation, the sign, frequency and rate of pressure changes at reservoirs beneath Campi Flegrei and Vesuvius can be very similar, allowing to infer that pressure changes originating from a magmatic or tectonic source external to the shallow volcano magma plumbing systems is a likely cause. Such a fluid-mechanical coupling sheds light on the earlier episodes of correlated eruptions and deformations occurring during the historical roman times.

  10. Controls on slow-moving landslides revealed by satellite and airborne InSAR (United States)

    Handwerger, Alexander L.; Fielding, Eric J.


    Landslides display a wide variety of behaviors ranging from slow persistent motion to rapid acceleration and catastrophic failure. Given the variety of possible behaviors, improvements to our understanding of landslide mechanics are critical for accurate predictions of landslide dynamics. To better constrain the mechanisms that control landslide motion, we use recent SAR data collected by Copernicus Sentinel-1A/B, NASA UAVSAR, JAXA ALOS-2, and DLR TerraSAR-X to quantify the time-dependent kinematics of over 200 slow-moving landslides in the Central and Northern California Coast Ranges. These landslides are ideally suited for InSAR investigations due to their size (up to 5 km in length and 0.5 km in width), persistent downslope motion with low velocities (m/yr), and sparse vegetation. We quantify the seasonal and multi-year changes in velocity driven by changes in precipitation and find that landslide velocity varies over both timescales. Over seasonal timescales, each landslide displays a period of acceleration that occurs within weeks of the onset of seasonal rainfall suggesting that motion is governed by precipitation-induced changes in pore-water pressure. We also examine the effects of multi-year climate variations (i.e., recent historic California drought and the possible wet period that began in late 2016) on the activity of landslides. We find that the drought has led to a decrease in annual displacement over the past several years and predict that a resurgence in annual displacement will occur with an increase in annual rainfall. Lastly, we use UAVSAR data acquired at 4 different look directions to quantify 3D surface displacement of multiple landslides and invert for their subsurface geometry (i.e. basal slip surface) using recently developed 3D mass conservation techniques. The application of NASA's UAVSAR data represents a major advance from previous InSAR studies on landslides in this region and provides one of the first 3D dataset that contains

  11. The deformation of ice-debris landforms in the Khumbu Region from InSAR (United States)

    Schmidt, D. A.; Barker, A. D.; Hallet, B.


    We present new interferometric synthetic aperture radar (InSAR) results for the Khumbu region, Nepal, using PALSAR data from the ALOS1 satellite. Glaciers and ice-debris landforms represent a critical water resource to communities in the Himalayas and other relatively arid alpine environments. Changes in climate have impacted this resource as the volume of ice decreases. The monitoring of rock glaciers and debris covered glaciers is critical to the assessment of these natural resources and associated hazards (e.g. Glacial Lake Outburst Floods--GLOFs). Satellite data provide one means to monitor ice-containing landforms over broad regions. InSAR measures the subtle deformation of the surface, with mm precision, that is related to deformation or changes in ice volume within rock glaciers and debris-covered glaciers. While previous work in the region had used C-band (6 cm wavelength) SAR data from the ERS satellite, we utilize L-band data (24 cm) from the ALOS satellite, which provides better coherence, especially where the phase gradient is large. After processing 20 differential interferograms that span from 2008 to 2011, we focus on the 5 interferograms with the best overall coherence. Based on three 45-day interferograms and two 3-year interferograms, all of which have relatively small perpendicular baselines (glaciers. From the 3-year interferograms, we map the boundary of active movement along the perimeter of the debris-covered toe of Khumbu Glacier. Movement over this longer time period leads to a loss of coherence, clearly delimiting actively moving areas. Of particular note, active movement is detected in the glacier-moraine dam of Imja Lake, which has implications for GLOF hazard. The significant vertical relief in the Himalaya region poses a challenge for doing differential radar interferometry, as artifacts in the digital elevation model (DEM) can propagate into the differential interferograms. Additionally, large changes in topography or glacier surfaces

  12. InSAR Measurements of Non-Tectonic Deformation Patterns in the Western Transverse Ranges, CA (United States)

    Phillips, J. R., III; Marshall, S. T.; Funning, G.


    We present results from analysis of twenty-two scenes from the Envisat satellite dated between February 2005 and September 2010 along track 213 frames 2907 and 2925 in the Western Transverse Ranges, CA. Persistent Scatterer InSAR (PSI) analysis of interferograms was performed using the StaMPS software package resulting in approximately 2 million PSI points with their associated line-of-sight velocities and time series. These data outline several zones of anthropogenic motion likely due to groundwater usage and oil extraction. We identify two instances of highly localized subsidence due to oil extraction: one of up to 6 mm/yr across a 3x5 km wide oval-shaped zone along the Ventura Ave anticline and another of up to 12 mm/yr across a 3x15 km region near Maricopa. Both of these features are observed in regions of known oil extraction, and the subsidence zones parallel the local fold axes, suggesting that these observed features are real and not merely a product of noise. We also observe several features potentially related to groundwater extraction. The groundwater-related signals tend to be less localized than the oil extraction signals and typically are centered around urban or agricultural areas. The PSI data show a broad zone of subsidence in the greater Oxnard region (10 mm/yr maximum), and more localized zones of subsidence centered in the cities of Carpenteria (4 mm/yr), Ojai (4 mm/yr), and Santa Clarita (5 mm/yr). Several additional regions of potentially anthropogenic motion are also present in the PSI data to which the root cause is unclear. For example, we observe localized uplift of 5 mm/yr centered in the Stevenson Ranch housing development, 8 mm/yr of subsidence centered about 5 km NW of Moorpark near a large agricultural nursery, and a potentially tectonic broad pattern of 4 mm/yr of uplift in the mountains of Los Padres National Forest near Frasier Mountain.

  13. Land subsidence due to groundwater withdrawal detected by InSAR time-series in Tazerbo well field, Libya (United States)

    Tufekci, Nesrin; Schoups, Gerrit; Mahapatra, Pooja; van de Giesen, Nick; Hanssen, Ramon F.


    The Tazerbo well field is one of the well fields designed within the Great Man-Made River Project (GMMRP), which aims to deliver water to the eastern coast of Libya through an underground pipe network. It consists of 108 wells in three rows, where the wells are separated 1.3 km in longitude and 10 km in latitude. The planned total groundwater withdrawal from all wells is 1 million m3/day. The water is pumped from the deep sandstone aquifer (Nubian sandstone), which is overlaid by a thick mudstone-siltstone aquitard. Being heavily pumped, the aquifer and fine-grained sediments of the aquitard are expected to compact in time resulting in land subsidence. In order to investigate the surface deformation caused by groundwater pumping in the Tazerbo well field, Interferometric Synthetic Aperture Radar (InSAR) technique was utilized. InSAR is widely used for monitoring land subsidence and can provide sub-cm scale deformation information over large areas. Using the Persistent Scatterer method, SAR time series of 20 Envisat images, spanning from 2004 to 2010, are employed to analyze spatial and temporal distribution of land subsidence induced by groundwater withdrawal. The results are in a good agreement with simulated subsidence. In addition, the spatial distribution of InSAR observations seems to be promising in terms of detecting spatial heterogeneity of aquifer material.

  14. Environmental Investigation and Evaluation of Land Subsidence in the Datong Coalfield Based on InSAR Technology

    Institute of Scientific and Technical Information of China (English)

    JIA Xiuming; MA Chao; ZHAO Anyuan


    Heavy mining of Jurassic and Carboniferous horizontal coal seams in the Datong coalfield has seriously affected the local geological environment, which is mainly manifested by such geohazards as soil avalanches, landslides, mudflows, surface subsidence, surface cracks, surface solid waste accumulation and surface deformation. More seriously, coal mining causes groundwater to leak.Overpumping of groundwater has resulted in substantial land subsidence of the urban area in Datong City. Based on the previous geo-environmental investigation in the work area, the authors used radar remote sensing techniques such as InSAR (synthetic aperture radar interferometry) and D-InSAR(differential synthetic aperture radar interferometry), supplemented by the optical remote sensing method, for geo-environmental investigation to ascertain the geo-environmentai background of the Datong Jurassic and Carboniferous-Permian coalfield and evaluate the effects of the geohazards, thus providing a basis for the geo-environmental protection, geohazard control and prevention, land improvement and optimization of the human environment. In this study 8 cog-nominal ERS-1/2 SAR data frames during 1992 to 2003 were used, but the following processing was made: (1) the multi-temporal SAR magnitude images were used to interpret the geological structure, vegetation, micro-geomorphology and drainage system; (2) the multi-temporal InSAR coherent images were used to make a classification of surface features and evaluate the coherence change due to coal mining; and (3) the multi-temporal cog-nominal SAR images were used to complete D-InSAR processing to remove the information of differential deformation areas (sites). In the end, a ten-year time series of differential interferograms were obtained using the multi-temporal cog-nominal SAR images. In the tests, 84 deformed areas (sites) were obtained, belonging to those in 1993-1996, 1996-1997, 1997-1998,1998-2001, 1998--2002 and 2001-2003 respectively. Of the

  15. New perspectives and advanced approaches on effectively processing Big InSAR data: from long term ERS archives to new Sentinel-1 massive data flow (United States)

    Casu, Francesco; De Luca, Claudio; Elefante, Stefano; Lanari, Riccardo; Manunta, Michele; Zinno, Ivana


    Advanced differential Synthetic Aperture Radar (SAR) Interferometry (InSAR) usually identifies a set of algorithms, tools and methodologies for the generation of Earth's surface deformation maps and time series computed from a sequence of multi-temporal differential SAR interferograms. Such techniques found their success on the large availability of SAR data archives acquired over time by several satellite systems. Indeed, the current radar Earth Observation (EO) scenario takes advantage of the widely diffused long-term C-band ESA (e.g. ERS-1, ERS-2 and ENVISAT) and Canadian (RADARSAT-1/2) SAR data archives, which have been acquired during the last 20 years, as well as of data sequences provided by the X-band generation SAR sensors, such as the COSMO-SkyMed (CSK) and TerraSAR-X (TSX) constellations. Moreover, a massive and ever increasing data flow will be further supplied by the recently launched (April 2014) Copernicus (European Union) SENTINEL-1A SAR satellite, which will also be paired during 2016 with the SENTINEL-1B twin system that will allow halving the constellation revisit time (from 12 to 6 days). In this context, the massive exploitation of these Big InSAR Data archives for the generation of advanced products will open new research perspectives to understand Earth's surface deformation dynamics at global scale. However, to reach this ambitious goal, Big InSAR Data has to be effectively exploited to generate accurate advanced products in short time frames. Therefore the need of new InSAR processing approaches, efficient algorithms and high performance computing facilities represents the basis for fully benefiting from such a Big Data. In this work we first present the recently proposed Parallel Small BAseline Subset (P-SBAS) InSAR algorithm that has been designed to process big volumes of InSAR data in short times and unsupervised manner by exploiting High Performance Computing (HPC) facilities. Then, we show how the P-SBAS approach is well suitable for

  16. Robust corrections for topographically-correlated atmospheric noise in InSAR data from large deforming regions (United States)

    Bekaert, David; Walters, Richard; Hooper, Andrew; Wright, Tim; Parker, Doug


    approximately zero. To ensure that tectonic deformation is not mapped into the atmospheric correction, we solve for the power-law function in a frequency band insensitive to deformation. In our work we include an analysis for temporal variations of the power-law coefficients by using sounding data. We test the effect of temporal variation in power-law coefficients and errors introduced by wrong a-priori information by using synthetic simulations. We used real data from Envisat interferograms covering Guerrero (Southern Mexico) as well as TerraSAR-X data over El Hierro (Spain) to further test our method. We evaluate the success of our new approach by comparing the estimated atmospheric delays with a conventional linear correction, spectrometer data from MERIS, global ERA-Interim weather model data and weather model data from WRF run at high resolution over our study region. After correction with our new technique, we find a better fit between the deformation maps derived from InSAR and GPS. The atmospheric correction models presented here, along with methods using MERIS and weather model data, will be made available to the community via a toolbox that is compatible with StaMPS.

  17. Detection of Sinkhole Activity in Central Florida with High Spatial-Resolution InSAR Time Series Observations (United States)

    Oliver-Cabrera, T.; Wdowinski, S.; Kruse, S.


    Central Florida's thick carbonate deposits and hydrological conditions make the area prone to sinkhole development. Sinkhole collapse is a major geologic hazard, threatening human life and causing substantial damage to property. Detecting sinkhole deformation before a collapse is a difficult task, due to small and typically unnoticeable surface changes. Most techniques used to map sinkholes, such as ground penetrating radar, require ground contact and are practical for localized (typically 2D, tens to hundreds of meters) surveys but not for broad study areas. In this study we use Persistent Scatterer (PS) time series analysis of Interferometric Synthetic Aperture Radar (InSAR), which is a very useful technique for detecting localized deformation while covering vast areas. We acquired SAR images over four locations in central Florida in order to detect possible pre-collapse or slow subsidence surface movements. The data used in this study were acquired by TerraSAR-X and COSMO-SkyMed satellites with pixel resolutions ranging between 25cm and 2m. To date, we have obtained four datasets, each of 25-30 acquisitions, covering a period of roughly one year over a total of roughly 2200 km2. We also installed two corner reflectors over a subsiding sinkhole located in an open vegetated area, to provide strong scattering and improve coherence over that particular location. We generate PS time series for each of the four datasets. Preliminary results show localized deformation at several houses and commercial buildings in several locations. Deforming areas vary in size from approximately 10mx20m of a single house to 60mx60m for a commercial building. On site ground penetrating radar surveys will be performed in these areas to verify their relationship to possible sinkhole activities. Our results also confirm that the corner reflectors improved PS detection over low coherence areas.

  18. Monitoring Landslides in Western Mountainous Areas of China Using Advanced Multi-Temporal InSAR Techniques (United States)

    Dong, Jie; Liao, Mingsheng; Zhang, Lu; Gong, Jianya


    Disasters, caused by landslide, rock fall, debris flow, ground fissure, etc., are one of the significant natural catastrophes, threatening and influencing the socio-economic conditions around the world. China is one of the countries that suffer heavily from such geo-hazards. And most landslides take place in the mountainous valley areas of western China. With its wide coverage and sub-centimeter accuracy, radar remote sensing has already proven its potential for remotely measuring unstable slopes. Differential InSAR (D-InSAR) is used to recognize known landslides and find potential unstable slopes in a region scale. Then, for a specific landslide, advanced multi-temporal InSAR method is exploited to characterize its surface deformation by obtaining time-series displacement on coherent targets. Among them, the PSI technique exploits only PSs exhibiting high phase stability in a stack of interferograms, which generally exist in urban areas. But, in the case of rural environment characterized by vegetated or low reflectivity homogeneous regions, few PSs could be identified. As a complement of persistent scatterers, distributed scatterers widely existing in rural areas can be exploited. DSs decorrelate slowly and can be found from homogeneous ground, scattered outcrops, debris flows, non-cultivated lands and desert areas. In this poster, a distributed scatterers-based InSAR technique, making use of PSs and DSs, is proposed. At first, we will use D-InSAR technique to detect landslides. Then, both PSI and DS-InSAR will be implemented to monitor interested landslides. And a comparison study of these two methods are conducted.

  19. Groundwater depletion in Central Mexico: Use of GRACE and InSAR to support water resources management (United States)

    Castellazzi, Pascal; Martel, Richard; Rivera, Alfonso; Huang, Jianliang; Pavlic, Goran; Calderhead, Angus I.; Chaussard, Estelle; Garfias, Jaime; Salas, Javier


    Groundwater deficits occur in several areas of Central Mexico, where water resource assessment is limited by the availability and reliability of field data. In this context, GRACE and InSAR are used to remotely assess groundwater storage loss in one of Mexico's most important watersheds in terms of size and economic activity: the Lerma-Santiago-Pacifico (LSP). In situ data and Land Surface Models are used to subtract soil moisture and surface water storage changes from the total water storage change measured by GRACE satellites. As a result, groundwater mass change time-series are obtained for a 12 years period. ALOS-PALSAR images acquired from 2007 to 2011 were processed using the SBAS-InSAR algorithm to reveal areas subject to ground motion related to groundwater over-exploitation. In the perspective of providing guidance for groundwater management, GRACE and InSAR observations are compared with official water budgets and field observations. InSAR-derived subsidence mapping generally agrees well with official water budgets, and shows that deficits occur mainly in cities and irrigated agricultural areas. GRACE does not entirely detect the significant groundwater losses largely reported by official water budgets, literature and InSAR observations. The difference is interpreted as returns of wastewater to the groundwater flow systems, which limits the watershed scale groundwater depletion but suggests major impacts on groundwater quality. This phenomenon is enhanced by ground fracturing as noticed in the field. Studying the fate of the extracted groundwater is essential when comparing GRACE data with higher resolution observations, and particularly in the perspective of further InSAR/GRACE combination in hydrogeology.

  20. Interseismic Deformation of the Altyn Tagh Fault Determined by Interferometric Synthetic Aperture Radar (InSAR Measurements

    Directory of Open Access Journals (Sweden)

    Sen Zhu


    Full Text Available The Altyn Tagh Fault (ATF is one of the major left-lateral strike-slip faults in the northeastern area of the Tibetan Plateau. In this study, the interseismic deformation across the ATF at 85°E was measured using 216 interferograms from 33 ENVISAT advanced synthetic aperture radar images on a descending track acquired from 2003 to 2010, and 66 interferograms from 15 advanced synthetic aperture radar images on an ascending track acquired from 2005 to 2010. To retrieve the pattern of interseismic strain accumulation, a global atmospheric model (ERA-Interim provided by the European Center for Medium Range Weather Forecast and a global network orbital correction approach were applied to remove atmospheric effects and the long-wavelength orbital errors in the interferograms. Then, the interferometric synthetic aperture radar (InSAR time series with atmospheric estimation model was used to obtain a deformation rate map for the ATF. Based on the InSAR velocity map, the regional strain rates field was calculated for the first time using the multi-scale wavelet method. The strain accumulation is strongly focused on the ATF with the maximum strain rate of 12.4 × 10−8/year. We also show that high-resolution 2-D strain rates field can be calculated from InSAR alone, even without GPS data. Using a simple half-space elastic screw dislocation model, the slip-rate and locking depth were estimated with both ascending and descending surface velocity measurements. The joint inversion results are consistent with a left-lateral slip rate of 8.0 ± 0.7 mm/year on the ATF and a locking depth of 14.5 ± 3 km, which is in agreement with previous results from GPS surveys and ERS InSAR results. Our results support the dynamic models of Asian deformation requiring low fault slip rate.

  1. Retrieval of interseismic displacement from multi-temporal InSAR measurements: challenges and solutions (United States)

    Zhang, L.; Ding, X.; Lu, Z.; Wen, Y.; Hu, J.


    High-resolution measurements of interseismic displacement are critical for understanding the earthquake cycle and for assessing earthquake hazard. Compared with sparsely located GNSS sites, it is well-known that by jointly analyzing a set of data over the same area acquired on different dates, multi-temporal InSAR (MTInSAR) is capable of remotely imaging interseismic deformation at an unprecedented level of spatial resolution. However conventional MTInSAR cannot hold a considerate promise for the precise retrieval of interseismic deformation in tectonically active zones where complicated atmospheric delay, orbital errors, and localized seasonal ground fluctuations commonly exist. Of interest in this study is to develop reliable solutions to correct or suppress these unwanted signals thereby to improve the accuracy of mapped interseismic displacement. Our technical innovations lie in the following aspects. According to different spatial-temporal characteristics, a joint model that takes both orbit errors and interseismic displacement as parameters is designed to isolate long wavelength motion from orbit error even in the case these two types of signals exhibit similar spatial patterns. To suppress the localized impacts (e.g., a portion of atmospheric artifacts and small-scale anthropogenic deformation), spatial correlation is employed as a constraint during the parameter estimation. The proposed solutions are evaluated by synthetic tests and applied to map the interseismic displacement over Eastern Turkey that spans the Arabia-Eurasia plate boundary zone from a large set of radar images acquired by Envisat/ASAR and Sentinel-1. The derived interseismic displacement validated by GPS data is further used to invert the slip rate and locking depth for the North and East Anatolian Faults. A cross-comparison with published results is also conducted.

  2. ICESat GLAS Elevation Changes and ALOS PALSAR InSAR Line-Of-Sight Changes on the Continuous Permafrost Zone of the North Slope, Alaska (United States)

    Muskett, Reginald


    Measuring centimeter-scale and smaller surface changes by satellite-based systems on the periglacial terrains and permafrost zones of the northern hemisphere is an ongoing challenge. We are investigating this challenge by using data from the NASA Ice, Cloud, and land Elevation Satellite Geoscience Laser Altimeter System (ICESat GLAS) and the JAXA Advanced Land Observing Satellite Phased Array type L-band Synthetic Aperture Radar (ALOS PALSAR) on the continuous permafrost zone of the North Slope, Alaska. Using the ICESat GLAS exact-repeat profiles in the analysis of ALOS PALSAR InSAR Line-Of-Sight (LOS) changes we find evidence of volume scattering over much of the tundra vegetation covered active-layer and surface scattering from river channel/banks (deposition and erosion), from rock outcropping bluffs and ridges. Pingos, ice-cored mounds common to permafrost terrains can be used as benchmarks for assessment of LOS changes. For successful InSAR processing, topographic and tropospheric phase cannot be assumed negligible and must be removed. The presence of significant troposphere phase in short-period repeat interferograms renders stacking ill suited for the task of deriving verifiable centimeter-scale surface deformation phase and reliable LOS changes. Ref.: Muskett, R.R. (2015), ICESat GLAS Elevation Changes and ALOS PALSAR InSAR Line-Of-Sight Changes on the Continuous Permafrost Zone of the North Slope, Alaska. International Journal of Geosciences, 6 (10), 1101-1115. doi:10.4236/ijg.2015.610086

  3. Thickness distribution of a cooling pyroclastic flow deposit on Augustine Volcano, Alaska: Optimization using InSAR, FEMs, and an adaptive mesh algorithm (United States)

    Masterlark, Timothy; Lu, Zhong; Rykhus, Russell P.


    Interferometric synthetic aperture radar (InSAR) imagery documents the consistent subsidence, during the interval 1992–1999, of a pyroclastic flow deposit (PFD) emplaced during the 1986 eruption of Augustine Volcano, Alaska. We construct finite element models (FEMs) that simulate thermoelastic contraction of the PFD to account for the observed subsidence. Three-dimensional problem domains of the FEMs include a thermoelastic PFD embedded in an elastic substrate. The thickness of the PFD is initially determined from the difference between post- and pre-eruption digital elevation models (DEMs). The initial excess temperature of the PFD at the time of deposition, 640 °C, is estimated from FEM predictions and an InSAR image via standard least-squares inverse methods. Although the FEM predicts the major features of the observed transient deformation, systematic prediction errors (RMSE = 2.2 cm) are most likely associated with errors in the a priori PFD thickness distribution estimated from the DEM differences. We combine an InSAR image, FEMs, and an adaptive mesh algorithm to iteratively optimize the geometry of the PFD with respect to a minimized misfit between the predicted thermoelastic deformation and observed deformation. Prediction errors from an FEM, which includes an optimized PFD geometry and the initial excess PFD temperature estimated from the least-squares analysis, are sub-millimeter (RMSE = 0.3 mm). The average thickness (9.3 m), maximum thickness (126 m), and volume (2.1 × 107m3) of the PFD, estimated using the adaptive mesh algorithm, are about twice as large as the respective estimations for the a priori PFD geometry. Sensitivity analyses suggest unrealistic PFD thickness distributions are required for initial excess PFD temperatures outside of the range 500–800 °C.

  4. Spatial and temporal variations in creep rate along the El Pilar fault at the Caribbean-South American plate boundary (Venezuela), from InSAR (United States)

    Pousse Beltran, Léa.; Pathier, Erwan; Jouanne, François; Vassallo, Riccardo; Reinoza, Carlos; Audemard, Franck; Doin, Marie Pierre; Volat, Matthieu


    In eastern Venezuela, the Caribbean-South American plate boundary follows the El Pilar fault system. Previous studies based on three GPS campaigns (2003-2005-2013) demonstrated that the El Pilar fault accommodates the whole relative displacement between the two tectonic plates (20 mm/yr) and proposed that 50-60% of the slip is aseismic. In order to quantify the possible variations of the aseismic creep in time and space, we conducted an interferometric synthetic aperture radar (InSAR) time series analysis, using the (NSBAS) New Small BAseline Subset method, on 18 images from the Advanced Land Observing Satellite (ALOS-1) satellite spanning the 2007-2011 period. During this 3.5 year period, InSAR observations show that aseismic slip decreases eastward along the fault: the creep rate of the western segment reaches 25.3 ± 9.4 mm/yr on average, compared to 13.4 ± 6.9 mm/yr on average for the eastern segment. This is interpreted, through slip distribution models, as being related to coupled and uncoupled areas between the surface and 20 km in depth. InSAR observations also show significant temporal creep rate variations (accelerations) during the considered time span along the western segment. The transient behavior of the creep is not consistent with typical postseismic afterslip following the 1997 Ms 6.8 earthquake. The creep is thus interpreted as persistent aseismic slip during an interseismic period, which has a pulse- or transient-like behavior.

  5. Estimating the 2008 Quetame (Colombia) earthquake source parameters from seismic data and InSAR measurements (United States)

    Dicelis, Gabriel; Assumpção, Marcelo; Kellogg, James; Pedraza, Patricia; Dias, Fábio


    Seismic waveforms and geodetic measurements (InSAR) were used to determine the location, focal mechanism and coseismic surface displacements of the Mw 5.9 earthquake which struck the center of Colombia on May 24, 2008. We determined the focal mechanism of the main event using teleseismic P wave arrivals and regional waveform inversion for the moment tensor. We relocated the best set of aftershocks (30 events) with magnitudes larger than 2.0 recorded from May to June 2008 by a temporary local network as well as by stations of the Colombia national network. We successfully estimated coseismic deformation using SAR interferometry, despite distortion in some areas of the interferogram by atmospheric noise. The deformation was compared to synthetic data for rectangular dislocations in an elastic half-space. Nine source parameters (strike, dip, length, width, strike-slip deformation, dip-slip deformation, latitude shift, longitude shift, and minimum depth) were inverted to fit the observed changes in line-of-sight (LOS) toward the satellite four derived parameters were also estimated (rake, average slip, maximum depth and seismic moment). The aftershock relocation, the focal mechanism and the coseismic dislocation model agree with a right-lateral strike-slip fault with nodal planes oriented NE-SW and NW-SE. We use the results of the waveform inversion, radar interferometry and aftershock relocations to identify the high-angle NE-SW nodal plane as the primary fault. The inferred subsurface rupture length is roughly 11 km, which is consistent with the 12 km long distribution of aftershocks. This coseismic model can provide insights on earthquake mechanisms and seismic hazard assessments for the area, including the 8 million residents of Colombia's nearby capital city Bogota. The 2008 Quetame earthquake appears to be associated with the northeastward "escape" of the North Andean block, and it may help to illuminate how margin-parallel shear slip is partitioned in the

  6. Monitoring subsidence with InSAR and inference of groundwater change (United States)

    Farr, T. G.


    Groundwater use is increasing in many parts of the world due to population pressure and reduced availability of surface water and rainfall. California's Central Valley and southern Arizona in particular have experienced subsidence in many groundwater basins in recent years due to groundwater overdraft. In order to make informed decisions for adaptation, water resource managers need to know the extent of groundwater depletion, both spatially and volumetrically, and to be able to monitor it over long periods. Water wells provide one solution, but owing to remoteness, funding limitations, a lack of wells, and the difficulty of mandating government monitoring of private wells, less direct methods are necessary. Mapping and monitoring subsidence and rebound from orbit with interferometric synthetic aperture radar (InSAR) may provide important indicators of groundwater state and dynamics for water resource managers as well as warnings of potential damage to infrastructure. We are working with water resource managers at the California Department of Water Resources to produce and update maps of subsidence 'hot-spots' where subsidence threatens to cause irreversible aquifer compaction and loss of groundwater storage capacity. In the future, Germany's TerraSAR-X, Italy's Cosmo SkyMed, Japan's PALSAR-2, Europe's Sentinels, and NASA's NISAR offer the promise of extending the time series of observations and expanding this capability to regions of the world with no effective means to monitor the state of their groundwater. This would provide societal benefits to large segments of the global population dependent on groundwater to bridge gaps in surface and rain water supply. As Earth's climate changes, monitoring of this critical resource will help reduce conflicts over water. * Work performed under contract to NASA

  7. Mojave Compliant Zone Structure and Properties: Constraints from InSAR and Mechanical Models (United States)

    Hearn, E. H.; Fialko, Y.; Finzi, Y.


    Long-lived zones with significantly lower elastic strength than their surroundings are associated with active Mojave faults (e.g., Li et al., 1999; Fialko et al., 2002, 2004). In an earthquake these weak features concentrate strain, causing them to show up as anomalous, short length-scale features in SAR interferograms (Fialko et al., 2002). Fault-zone trapped wave studies indicate that the 1999 Hector Mine earthquake caused a small reduction in P- and S-wave velocities in a compliant zone along the Landers earthquake rupture (Vidale and Li, 2003). This suggests that coseismic strain concentration, and the resulting damage, in the compliant zone caused a further reduction in its elastic strength. Even a small coseismic strength drop should make a compliant zone (CZ) deform, in response to the total (not just the coseismic) stress. The strain should be in the sense which is compatible with the orientations and values of the region's principal stresses. However, as indicated by Fialko and co-workers (2002, 2004), the sense of coseismic strain of Mojave compliant zones was consistent with coseismic stress change, not the regional (background) stress. Here we use finite-element models to investigate how InSAR measurements of Mojave compliant zone coseismic strain places limits on their dimensions and on upper crustal stresses. We find that unless the CZ is shallow, narrow, and has a high Poisson's ratio (e.g., 0.4), CZ contraction under lithostatic stress overshadows deformation due to deviatoric background stress or coseismic stress change. We present ranges of CZ dimensions which are compatible with the observed surface deformation and address how these dimensions compare with new results from damage-controlled fault evolution models.

  8. InSAR observations of lake loading at Yangzhuoyong Lake, Tibet: Constraints on crustal elasticity (United States)

    Zhao, Wenliang; Amelung, Falk; Doin, Marie-Pierre; Dixon, Timothy H.; Wdowinski, Shimon; Lin, Guoqing


    We use Envisat 2003-2010 InSAR imagery over Yangzhuoyong Lake in southeastern Tibet to study the elastic response of the Earth's crust to variations in lake level. The net lake level drop during our study period is ∼3 m with seasonal variations of more than 1 m. The time-series close to the lake center shows a high correlation with the lake level history. Near the lake center the unit response with respect to lake level change is 2.5 mm/m in radar line-of-sight direction, or ∼2.7 mm/yr in vertical direction, corresponding to a vertical response of ∼4.3 mm/Gt load change. We show that the observations are most sensitive to the elastic properties of the crust in the 5-15 km depth range and explain them with a layered elastic half-space model with a Young's modulus of 50 ± 9GPa Young's modulus in the top 15 km of the crust and using moduli inferred from seismology at greater depth. The inferred Young's modulus is ∼25% smaller than the seismic modulus, which we attribute to damaged rock and the presence of fluids.

  9. Mapping and monitoring coal mine subsidence using LiDAR and InSAR

    Energy Technology Data Exchange (ETDEWEB)

    Froese, C.R.; Mei, S. [Alberta Geological Survey, Edmonton, AB (Canada). Energy Resources Conservation Board


    In the early 1900s, the abandonment of coal mines in Alberta was not regulated and closure documentation was poor. Although the general locations of mines are known, the locations of the specific adits and shafts are not. As such, there are many cases in southwestern Alberta where infrastructure was built on top of old coal mine workings without any detailed records of the abandoned mine or displacement monitoring. The crowns of these workings have been subject to ongoing strain that is reflected at the surface. The rate at which the strain is progressing prior to collapse is not well understood. Mitigation of collapse events is site specific and reactive. This paper demonstrated that airborne LiDAR and spaceborne InSAR technologies can provide valuable information on the distribution of abandoned underground coal mine workings. Both remote sensing techniques were used on Turtle Mountain in the Crowsnest Pass to obtain quantitative information on landslide mechanics, including the patterns and rate of ground movement and subsidence. These techniques can be used to map the location of surface collapse and delineate the location of the coal mine workings that were not previously documented. It was concluded that these technologies will likely become more readily available in the future and incorporated into geo-engineering practices for use in ground hazard detection, monitoring and management. 8 refs., 6 figs.

  10. InSAR Observations and Modeling of Anthropogenic Surface Deformation in the Alberta Oil Sands (United States)

    Pearse, J.; Singhroy, V.; Samsonov, S. V.; Li, J.


    Recent Interferometric Synthetic Aperture Radar (InSAR) observations over northern Alberta, Canada show persistent surface uplift occurring at rates of 1-4 cm/year, localized at several sites where the Steam-Assisted Gravity Drainage (SAGD) technique is currently being used to extract bitumen from the Athabasca oil sands. We find that uplift rates above the horizontal injector wells are strongly correlated with rates of steam injection, even though there is a net fluid loss from the reservoir pore space as oil and water are withdrawn through the production wells. In combination with available steam injection and bitumen production data at four sites, we use numerical reservoir flow models to explain how the thermal and geomechanical effects of steam injection on an oil sand reservoir can generate uplift at the surface. Results of our numerical experiments show that persistent surface heave consistent with observed rates can be driven by stress changes in the reservoir due to porous flow and thermal expansion.

  11. Decomposing InSAR LOS displacement into co-seismic dislocation with a linear interpolation model: A case study of the Kunlun Mountain Ms=8.1 earthquake

    Institute of Scientific and Technical Information of China (English)


    It has always been a difficult problem to extract horizontal and vertical displacement components from the InSAR LOS (Line of Sight) displacement since the advent of monitoring ground surface deformation with InSAR technique. Having tried to fit the firsthand field investigation data with a least squares model and obtained a preliminary result, this paper, based on the previous field data and the InSAR data, presents a linear cubic interpolation model which well fits the feature of earthquake fracture zone. This model inherits the precision of investigation data;moreover make use of some advantages of the InSAR technique, such as quasi-real time observation, continuous recording and all-weather measurement. Accordingly, by means of the model this paper presents a method to decompose the InSAR slant range co-seismic displacement (i.e. LOS change) into horizontal and vertical displacement components. Approaching the real motion step by step, finally a serial of curves representing the co-seismic horizontal and vertical displacement component along the main earthquake fracture zone are approximately obtained.

  12. Remote Sensing of Deformation of a High Concrete-Faced Rockfill Dam Using InSAR: A Study of the Shuibuya Dam, China

    Directory of Open Access Journals (Sweden)

    Wei Zhou


    Full Text Available Settlement is one of the most important deformation characteristics of high concrete faced rockfill dams (CFRDs, >100 m. High CFRDs safety would pose a great threat to the security of people’s lives and property downstream if this kind of deformation were not to be measured correctly, as traditional monitoring approaches have limitations in terms of durability, coverage, and efficiency. It has become urgent to develop new monitoring techniques to complement or replace traditional monitoring approaches for monitoring the safety and operation status of high CFRDs. This study examines the Shuibuya Dam (up to 233.5 m in height in China, which is currently the highest CFRD in the world. We used space-borne Interferometric Synthetic Aperture Radar (InSAR time series to monitor the surface deformation of the Shuibuya Dam. Twenty-one ALOS PALSAR images that span the period from 28 February 2007 to 11 March 2011 were used to map the spatial and temporal deformation of the dam. A high correlation of 0.93 between the InSAR and the in-situ monitoring results confirmed the reliability of the InSAR method; the deformation history derived from InSAR is also consistent with the in-situ settlement monitoring system. In addition, the InSAR results allow continuous investigation of dam deformation over a wide area that includes the entire dam surface as well as the surrounding area, offering a clear picture continuously of the dam deformation.

  13. Inventory of anthropogenic surface deformation measured by InSAR in the western U.S./Mexico and possible impacts on GPS measurements (United States)

    Semple, A.; Pritchard, M. E.; Taylor, H.


    The western US and Mexico are deforming at several spatial scales that can be measured by ground and satellite observations like GPS and Interferometric Synthetic Aperture Radar (InSAR). Many GPS stations have been installed throughout this area to monitor ground deformation caused by large scale tectonic processes; however, several studies have noted that the data recorded at a GPS station can be contaminated by local, non-tectonic ground deformation. In this study, we use InSAR to examine deformation from various sources in the western US and Mexico. We chose this method due to the spatially large study area and the availability and temporal coverage of SAR imagery. We use SAR images acquired by the satellites Envisat, ERS-1 and ERS-2 over a time period from 1992-2010 to create several time series. Data from the ALOS satellite between 2006-2011 are also used in some areas. We use these time series analysis along with previously published results to observe and catalogue various sources of surface deformation in the western US and Mexico - from groundwater pumping, geothermal activity, mining, hydrocarbon production, and other sources. We then use these results to identify GPS stations that have potentially been contaminated by non-tectonic deformation signals. We document more than 150 distinct regions of non-tectonic and likely anthropogenic deformation. We have located 82 GPS stations within 20km of the center of at least one of the non-tectonic deformation signals we have identified. It is likely that the data from these 82 GPS stations have been contaminated by local anthropogenic deformation. Some examples of previously unpublished non-tectonic deformation we have seen in this study include but are not limited to, subsidence due to groundwater extraction in Jesus Garcia, Mexico, both uplift and subsidence due to natural gas extraction at Jonah Field in Sublette County, WY, and uplift due to a water recharge project in Tonopah, AZ.

  14. Geohazards affecting UNESCO WHL sites in the UK observed from geological data and satellite InSAR (United States)

    Cigna, Francesca; Tapete, Deodato; Lee, Kathryn


    Geohazards pose significant threats to cultural and natural heritage worldwide. In the UK, only 1 out of 29 UNESCO World Heritage List (WHL) sites has been inscribed on the list of World Heritage in Danger, whilst it is widely accepted that many more could be affected by geohazards. In this paper we set out the foundations of a methodological approach to analyse geological, geohazard and remote sensing data available at the British Geological Survey to retrieve an overview of geohazards affecting the UK WHL sites. The Castles and Town Walls (constructed in the time of King Edward I) in Gwynedd in north Wales are used as test sites to showcase the methodology for geohazard assessment at the scale of individual property also to account for situations of varied geology and local topography across multiproperty WHL sites. How such baseline geohazard assessment can be combined with space-borne radar interferometry (InSAR) data is showcased for the four UNESCO WHL sites located in Greater London. Our analysis feeds into the innovative contribution that the JPI-CH project PROTHEGO `PROTection of European cultural HEritage from GeOhazards' ( is making towards mapping geohazards in the 400+ WHL sites of Europe by exploiting non-invasive remote sensing methods and surveying technologies.

  15. Seismic imaging beneath an InSAR anomaly in eastern Washington State: Shallow faulting associated with an earthquake swarm in a low-hazard area (United States)

    Stephenson, William J.; Odum, Jackson K.; Wicks, Chuck; Pratt, Thomas L.; Blakely, Richard J.


    In 2001, a rare swarm of small, shallow earthquakes beneath the city of Spokane, Washington, caused ground shaking as well as audible booms over a five‐month period. Subsequent Interferometric Synthetic Aperture Radar (InSAR) data analysis revealed an area of surface uplift in the vicinity of the earthquake swarm. To investigate the potential faults that may have caused both the earthquakes and the topographic uplift, we collected ∼3  km of high‐resolution seismic‐reflection profiles to image the upper‐source region of the swarm. The two profiles reveal a complex deformational pattern within Quaternary alluvial, fluvial, and flood deposits, underlain by Tertiary basalts and basin sediments. At least 100 m of arching on a basalt surface in the upper 500 m is interpreted from both the seismic profiles and magnetic modeling. Two west‐dipping faults deform Quaternary sediments and project to the surface near the location of the Spokane fault defined from modeling of the InSAR data.

  16. Coseismic and early postseismic deformation due to the 25 April 2015, Mw 7.8 Gorkha, Nepal, earthquake from InSAR and GPS measurements (United States)

    Sreejith, K. M.; Sunil, P. S.; Agrawal, Ritesh; Saji, Ajish P.; Ramesh, D. S.; Rajawat, A. S.


    Analysis of Interferometric Synthetic Aperture Radar (InSAR) and Global Positioning System (GPS) data reveals coseismic and early postseismic (4-88 days) surface displacements associated with the 25 April 2015, Mw 7.8 Gorkha, Nepal, earthquake. The pattern of early postseismic surface uplift and subsidence is found to be opposite to that of the coseismic motion. InSAR and GPS data were jointly inverted for coseismic and postseismic slip on the Main Himalayan Thrust (MHT). We consider a complex ramp-flat-ramp-flat subsurface structure of the MHT with four connected fault planes dipping toward north from the Main Frontal Thrust (MFT). The inverted coseismic slip distribution follows an elliptical pattern, extending east-southeastward from the hypocenter with maximum amplitude of 5.7 m above the upper edge of the midcrustal ramp. We infer early postseismic afterslip (4-16 days) of 0.2-0.47 m toward downdip of the coseismic slip asperity and another patch with 0.1-0.2 m slip toward east. The shallow portion of the MHT toward south is found to have remained unruptured during the earthquake, nor did it slip aseismically after the earthquake, suggesting possibility of large events in the future.

  17. The 2008 Nura Mw6.7 earthquake: A shallow rupture on the Main Pamir Thrust revealed by GPS and InSAR

    Directory of Open Access Journals (Sweden)

    Xuejun Qiao


    Full Text Available The 2008 Nura Mw6.7 earthquake occurred in front of the Trans-Alai Range, central Asia. We present Interferometric Synthetic Aperture Radar (InSAR measurements of its coseismic ground deformation that are available for a major earthquake in the region. Analysis of the InSAR data shows that the earthquake ruptured a secondary fault of the Main Pamir Thrust for about 20 km. The fault plane striking N46°E and dipping 48°SE is dominated by thrust slip up to 3 m, most of which is confined to the uppermost 2–5 km of the crust, similar to the nearby 1974 Mw7.0 Markansu earthquake. The elastic model of interseismic deformation constrained by GPS measurements suggests that the two earthquakes may have resulted from the failures of two high-angle reverse faults that are about 10 km apart and rooted in a locked décollement at depths of 5–6 km. The elastic strain is built up by a freely creeping décollement at about 16 mm/a.

  18. ERS-ENVISAT InSAR deformation time-series: a powerful tool to investigate long term surface deformation of large areas (United States)

    Lanari, Riccardo


    Satellite time series have already provided key measurements to retrieve information on the dynamic nature of Earth surface processes. We exploit in this work the availability of the large archives of spaceborne Synthetic Aperture Radar (SAR) data acquired by the ERS-1/2 and ENVISAT sensors of the European Space Agency (ESA) during the 1992-2009 time period, in order to investigate long term surface deformation of large areas. To achieve this result we take advantage of the Differential SAR Interferometry (InSAR) algorithm referred to as Small BAseline Subset (SBAS) technique (Berardino et al., 2002), which allows us to generate mean deformation velocity maps and corresponding time-series by exploiting temporally overlapping SAR dataset collected by the ERS and ENVISAT sensors (Pepe et al., 2005). In particular, we focus on the results obtained by retrieving ERS-ENVISAT deformation time-series from 1992 till today in selected case studies relevant to different scenarios. We start from the analysis of the Mt. Etna volcano (Italy) and the Napoli Bay area (Italy), the latter including three volcanic systems (the Campi Flegrei caldera, the Somma-Vesuvio volcanic complex and the Ischia island) and the city of Napoli. In addition, we present the results relevant to the cities of Istanbul (Turkey) and Roma (Italy). The overall analyses are carried out by using averaged (multilook) InSAR interferograms with a spatial resolution of about 100 x 100 m. Moreover, in selected zones we further investigate localized phenomena by zooming in the areas of interest and carrying out a InSAR analysis at full spatial resolution scale (Lanari et al., 2004). In these cases we also exploit the doppler centroid variations of the post-2000 acquisitions of the ERS-2 sensor and the carrier frequency difference between the ERS-1/2 and the ENVISAT systems in order to maximize the number of investigated SAR pixels and to improve their geocoding. The presented results demonstrate the unique

  19. Monitoring of ground surface deformation in mining area with InSAR technique%利用InSAR技术监测矿区地表形变

    Institute of Scientific and Technical Information of China (English)

    朱建军; 邢学敏; 胡俊; 李志伟


    The application status and research progress of InSAR technique in the monitoring of the ground surface deformation in mining area were introduced. Firstly, the advantages of D-InSAR technique were analyzed by comparing to the traditional surveying methods. Then, the limitations of D-InSAR in the mining deformation detection were described. According to the limitations of the traditional D-InSAR method, the advanced InSAR technique, e.g., small baseline subset (SBAS), permanent scatterer (PS) and corner reflector (CR) techniques were discussed. Using real mining subsidence monitoring as example, the characteristics and application status of those advanced InSAR techniques were studied, and the key problems still existing in the current research were summarized. Finally, it is indicated that the development trend of InSAR monitoring surface deformation in mining area is the combination of advanced InSAR and high-resolution SAR images.%介绍了InSAR技术在矿区地表形变监测中的应用现状及进展,分析了D-InSAR技术相比于传统测量手段的优势,并指出其在矿区地表形变监测中的不足.针对传统D-InSAR技术的局限性,重点讨论了短基线(SBAS)、永久散射体(PS)和角反射器(CR)等高级差分干涉技术,并结合矿区沉降监测实例,分析了其特点与应用现状,讨论了现有研究中仍存在的问题.高级InSAR技术和高分辨率SAR影像的结合将是矿区地表形变监测的发展趋势.

  20. Shortcomings of InSAR for studying megathrust earthquakes: The case of the M w 9.0 Tohoku-Oki earthquake

    KAUST Repository

    Feng, Guangcai


    Interferometric Synthetic Aperture Radar (InSAR) observations are sometimes the only geodetic data of large subduction-zone earthquakes. However, these data usually suffer from spatially long-wavelength orbital and atmospheric errors that can be difficult to distinguish from the coseismic deformation and may therefore result in biased fault-slip inversions. To study how well InSAR constrains fault-slip of large subduction zone earthquakes, we use data of the 11 March 2011 Tohoku-Oki earthquake (Mw9.0) and test InSAR-derived fault-slip models against models constrained by GPS data from the extensive nationwide network in Japan. The coseismic deformation field was mapped using InSAR data acquired from multiple ascending and descending passes of the ALOS and Envisat satellites. We then estimated several fault-slip distribution models that were constrained using the InSAR data alone, onland and seafloor GPS/acoustic data, or combinations of the different data sets. Based on comparisons of the slip models, we find that there is no real gain by including InSAR observations for determining the fault slip distribution of this earthquake. That said, however, some of the main fault-slip patterns can be retrieved using the InSAR data alone when estimating long wavelength orbital/atmospheric ramps as a part of the modeling. Our final preferred fault-slip solution of the Tohoku-Oki earthquake is based only on the GPS data and has maximum reverse- and strike-slip of 36.0 m and 6.0 m, respectively, located northeast of the epicenter at a depth of 6 km, and has a total geodetic moment is 3.6 × 1022 Nm (Mw 9.01), similar to seismological estimates.

  1. Properties of L-band differential InSAR for monitoring mining-induced subsidence in coalfield of Jining, Northern China

    Institute of Scientific and Technical Information of China (English)

    陶秋香; 刘国林


    The properties and feasibility of L-band differential InSAR for detecting and monitoring mining-induced subsidence were systematically analyzed and demonstrated. The largest monitored subsidence gradient of 7.9×10-3 and magnitude of 91 cm were firstly derived by theoretical derivation. Then, the stronger phase maintaining capacity and weaker sensitivity to minor land subsidence compared with C-band DInSAR were illustrated by phase simulation of the actual mine subsidence. Finally, the data processing procedure of two-pass DInSAR was further refined to accurately observe subsidence of a coalfield of Jining in Northern China using 7 ALOS PALSAR images. The largest monitored subsidence magnitude of 39.22 cm and other properties were better investigated by testing results interpretation and subsidence analysis, and the absolute difference varying from 0.5 mm to 17.9 mm was obtained by comparison with leveling-measured subsidence. All of results show that L-band DInSAR technique can investigate the location, amount, area and other detailed subsidence information with relatively higher accuracy.

  2. Land subsidence, Ground Fissures and Buried Faults: InSAR Monitoring of Ciudad Guzmán (Jalisco, Mexico

    Directory of Open Access Journals (Sweden)

    Carlo Alberto Brunori


    Full Text Available We study land subsidence processes and the associated ground fissuring, affecting an active graben filled by thick unconsolidated deposits by means of InSAR techniques and fieldwork. On 21 September 2012, Ciudad Guzmán (Jalisco, Mexico was struck by ground fissures of about 1.5 km of length, causing the deformation of the roads and the propagation of fissures in adjacent buildings. The field survey showed that fissures alignment is coincident with the escarpments produced on 19 September 1985, when a strong earthquake with magnitude 8.1 struck central Mexico. In order to detect and map the spatio-temporal features of the processes that led to the 2012 ground fissures, we applied InSAR multi-temporal techniques to process ENVISAT-ASAR and RADARSAT-2 satellite SAR images acquired between 2003 and 2012. We detect up to 20 mm/year of subsidence of the northwestern part of Ciudad Guzmán. These incremental movements are consistent with the ground fissures observed in 2012. Based on interferometric results, field data and 2D numerical model, we suggest that ground deformations and fissuring are due to the presence of areal subsidence correlated with variable sediment thickness and differential compaction, partly driven by the exploitation of the aquifers and controlled by the distribution and position of buried faults.

  3. Interseismic megathrust coupling beneath the Nicoya Peninsula, Costa Rica, from the joint inversion of InSAR and GPS data (United States)

    Xue, Lian; Schwartz, Susan; Liu, Zhen; Feng, Lujia


    The Nicoya Peninsula, Costa Rica, was struck by a long-anticipated and gap-filling Mw 7.6 earthquake in 2012. To study interseismic strain accumulation on the megathrust beneath the Nicoya Peninsula, we present an improved interseismic coupling model by integrating interferometric synthetic aperture radar (InSAR) and GPS data. Our model reveals three strongly coupled patches. The first strongly coupled patch locates beneath the Nicoya Peninsula and ruptured during the 2012 earthquake. The second strongly coupled patch locates offshore the central Nicoya Peninsula and remained largely unbroken. However, this region is close to and possibly intermingled with shallow slow slip and tremor, suggesting that accumulated strain in this region may be released both seismically and aseismically. The third strongly coupled patch offshore of the southeastern end of Nicoya overlaps part of the coseismic rupture of the 1990 Mw 7.0 Nicoya Gulf earthquake, indicating that significant strain has re-accumulated since this event. Incorporating InSAR data provides a more refined interseismic coupling model than using GPS alone and allows for a more reliable comparison with local seismic and aseismic activities. This comparison indicates that strongly locked regions during the interseismic stage are the loci of coseismic slip, and deep slow slip and low-frequency earthquakes occur in regions of low coupling or transition zones from low to high coupling, while shallow slow slip and tremor commingle with strongly coupled regions. Our study demonstrates that InSAR data can be used to recover small long-wavelength deformation signals with refined resolution in challenging subduction zone environments when integrated with GPS observations.

  4. On the Design of Radar Corner Reflectors for Deformation Monitoring in Multi-Frequency InSAR

    Directory of Open Access Journals (Sweden)

    Matthew C. Garthwaite


    Full Text Available Trihedral corner reflectors are being increasingly used as point targets in deformation monitoring studies using interferometric synthetic aperture radar (InSAR techniques. The frequency and size dependence of the corner reflector Radar Cross Section (RCS means that no single design can perform equally in all the possible imaging modes and radar frequencies available on the currently orbiting Synthetic Aperture Radar (SAR satellites. Therefore, either a corner reflector design tailored to a specific data type or a compromise design for multiple data types is required. In this paper, I outline the practical and theoretical considerations that need to be made when designing appropriate radar targets, with a focus on supporting multi-frequency SAR data. These considerations are tested by performing field experiments on targets of different size using SAR images from TerraSAR-X, COSMO-SkyMed and RADARSAT-2. Phase noise behaviour in SAR images can be estimated by measuring the Signal-to-Clutter ratio (SCR in individual SAR images. The measured SCR of a point target is dependent on its RCS performance and the influence of clutter near to the deployed target. The SCR is used as a metric to estimate the expected InSAR displacement error incurred by the design of each target and to validate these observations against theoretical expectations. I find that triangular trihedral corner reflectors as small as 1 m in dimension can achieve a displacement error magnitude of a tenth of a millimetre or less in medium-resolution X-band data. Much larger corner reflectors (2.5 m or greater are required to achieve the same displacement error magnitude in medium-resolution C-band data. Compromise designs should aim to satisfy the requirements of the lowest SAR frequency to be used, providing that these targets will not saturate the sensor of the highest frequency to be used. Finally, accurate boresight alignment of the corner reflector can be critical to the overall

  5. Co- and post-seismic crustal deformation of the 2014 Iquique-Pisagua Earthquake observed with InSAR and GPS data (United States)

    Eckelmann, Felix; Moreno, Marcos; Metzger, Sabrina; Bartsch, Mitja; Oncken, Onno; Baez, Juan Carlos; Klotz, Jürgen


    The western margin of South America is dominated by a 6000 km long subduction zone that drives the seismogenic processes of megathrust earthquakes along the Chilean coast. Almost all seismotectonic segments at this highly active plate boundary have broken within the last decades producing great earthquakes (MW>8.5). The only segment that has not ruptured since 1877 is known as Northern Chile-Southern Peru seismic gap. It is located between 18°-22°S latitude and has the potential of generating a Mw=9+ earthquake. On 1 April 2014, the Iquique-Pisagua earthquake (MW>8.5) affected the north-central part of this gap. This earthquake was proceeded by a transient deformation 15 days before the main shock and followed by a MW=7.6 aftershock. In this study, we analyze and model the co- and postseismic crustal deformation related to the Iquique-Pisagua earthquake by means of InSAR and GPS measurements. In the modeling, we perform a joint inversion of InSAR and GPS data by applying principle component analysis and the decomposition of displacement vectors in an elastic half-space. Our InSAR observations include three TerraSAR-X images from three years before the earthquake and one, resp. 79 days after the event. This dataset allows us to separate deformation caused by the main event and the aftershock two days later. Moreover, we present five Radarsat-2 scenes from four days before and three, 19, 44 and 76 days after the earthquake. Our GPS data include time-series of more than 40 continuous stations of the Integrated Plate Boundary Observatory Chile (IPOC) and 60 survey-mode GPS data. The co-seismic interferograms show a circular deformation pattern centered at the North Chilean coast near the city of Iquique. The cGPS recorded a maximum horizontal displacement of 80 cm trenchward. In the post-seismic interferograms the deformation is much smaller and somewhat less symmetric. The first two month of postseismic deformation show a cumulative GPS displacement up to 10 cm

  6. Interseismic deformation of the Central Tibetan Plateau measured using InSAR (United States)

    Garthwaite, M. C.; Wright, T. J.


    Contrasting models have been proposed to describe the ongoing deformation of the Tibetan plateau as a result of the shortening imposed by the India-Asia Collision. One extreme involves rigid rotations of coherent blocks bounded by major faults which penetrate the entire lithosphere. The rigidity of each block implies that there is minimal internal deformation. This description implies relatively high slip rates on block bounding faults separated by narrow shear zones. In the alternative extreme, the bulk continental lithosphere is considered to deform continuously as a viscous fluid. Deformation in the brittle upper crust is driven by tractions imparted on its base from the viscous layer beneath, and distributed on a large number of shallow faults throughout the deforming zone. As a result, slip rates on faults are lower, and the number of discrete crustal blocks is larger. Geodetic observations of interseismic deformation around locked faults often show concentrated strain. If crustal blocks are separated by distances less than or equal to the locking depth (i.e. many small blocks), their straining zones will merge together. If a few large blocks exist, their strain zones should be distinct. There are very few GPS measurements of surface velocity in the plateau interior, therefore it has been difficult to verify either of the proposed models. Interferometric synthetic aperture radar (InSAR) is a powerful technique which dramatically increases the spatial density of velocity measurements. By combining multiple interferograms, interseismic strain can be measured using InSAR with an accuracy of approximately 6 millimetres per year (Wang et. al. GRL, 2009). We use 32 Envisat ASAR images acquired between 2003 and 2009 on descending track 176 in the plateau centre. The swath length of ~1500 km spans the entire plateau including the four major east-west trending strike-slip faults of Tibet - the Altyn Tagh, Kunlun, Jiali, and Xianshuihe. Interferograms are processed

  7. Complex Deformation Monitoring over the Linfen–Yuncheng Basin (China with Time Series InSAR Technology

    Directory of Open Access Journals (Sweden)

    Cheng-sheng Yang


    Full Text Available The Linfen–Yuncheng basin is an area prone to geological disasters, such as surface subsidence, ground fissuring, fault activity, and earthquakes. For the purpose of disaster prevention and mitigation, Interferometric Synthetic Aperture Radar (InSAR was used to map ground deformation in this area. After the ground deformation characteristics over the Linfen–Yuncheng basin were obtained, the cross-correlations among regional ground subsidence, fault activity, and underground water level were analyzed in detail. Additionally, an area of abnormal deformation was found and examined. Through time series deformation monitoring and mechanism inversion, we found that the abnormal deformation was related mainly to excessive groundwater exploitation.

  8. Ground Surface Deformation around Tehran due to Groundwater Recharge: InSAR Monitoring. (United States)

    Gourmelen, N.; Peyret, M.; Fritz, J. F.; Cherry, J.


    Tehran is located on an active tectonic and seismic zone. The surface deformation monitoring provides a powerful tool for getting a better understanding of faults kinematics and mechanisms. Used in conjunction with GPS networks, InSAR (Interferometric Synthetic Aperture Radar) provides dense and precise deformation measurements which are essential for mapping complex heterogeneous deformation fields. Moreover, urban and arid areas preserve interferometric phase coherence. The archived acquisitions of ERS that span 9 months between September 1998 and June 1999 reveal wide areas of surface uplift (by as much as 9 cm). This vertical deformation (gradual in time) has probably no tectonic meaning but is rather the ground response to ground water recharge. These zones are all located dowstream of large alluvial fans like the one of Karaj. The variation of effective stress caused by intersticial water draining could explain such surface deformation. It can also be noticed that some faults act as boundary for these deformation zones and fluid motion. The understanding of this deformation is relevant for groundwater monitoring and urban developement management. It is also necessary for discriminating it from tectonic deformation that also occurs on this zone. Due to the lack of attitude control of satellite ERS-2 since February 2001, the last images acquired could not be combined with the former acquisitions. Nevertheless, we expect to be able to enrich our set of images in order to map tectonic deformation on a longer period and to monitor in a more continuous way the deformation due to groundwater evolution. This would allow to quantify the permanent and reversible part of this signal.

  9. 一种基于相干性本质的InSAR方位向预滤波方法%An Improved Method for InSAR Azimuth Prefiltering Based on Coherence Principle

    Institute of Scientific and Technical Information of China (English)

    郭交; 李真芳; 刘艳阳; 保铮


    本文针对合成孔径雷达干涉测量(SAR Interferometry,InSAR)数据处理中的方位向预滤波问题,提出了一种改进的InSAR方位向预滤波方法.首先对InSAR成像系统的几何模型和雷达回波相干性的本质进行了分析,在此基础上提出在方位向只有来自相同方位角空间采样位置的回波信号才具有相干性,即能够用于相干干涉处理,然后根据相干性的本质,提出了一种基于相同方位角的预滤波方法.仿真试验结果和实例分析表明,本文提出的方位向预滤波算法能够有效地保留相干性信息,提高SAR图像对之间的相干性.%Aiming at dealing with the problem of azimuth prefiltering during the interferometric processing procedures, this paper proposed an improved method for InSAR azimuth prefiltering. Based on the theoretic analysis of the InSAR imaging geometry and the principles of coherence, this paper proposes that only the radar echoes coming from the space sampling positions with the same azimuth angles are coherent,I.e. .available for interferometric process.Then an improved method for InSAR azimuth prefiltering is proposed according to the same azimuth angle extension. Finally,The computer simulation and practical examples analysis are shown to prove that the proposed algorithm can improve the coherence between complex SAR images while preserving the coherent information effectively.

  10. Shallow evolution of Santorini volcano constrained by InSAR and GPS measurements (United States)

    Parks, Michelle; Biggs, Juliet; England, Philip; Mather, Tamsin; Nomikou, Paraskevi; Palamartchouk, Kirill; Papanikolaou, Xanthos; Paradissis, Demitris; Parsons, Barry; Pyle, David; Raptakis, Costas; Zacharis, Vangelis


    Santorini, a major caldera volcano in the South Aegean, entered a period of unrest in January 2011. This was characterised by the onset of detectable seismicity and caldera-wide uplift. For the past 360,000 years, the volcano has generated major explosive eruptions every 20,000 to 30,000 years, which are separated by phases during which andesite shields and dacite lava domes are built by multiple smaller effusive eruptions. Since the last major eruption in approximately 1620 BC (Minoan eruption), Santorini has been in a dome-forming phase. Here we present measurements of surface deformation prior to and during the recent period of unrest, using Interferometric Synthetic Aperture Radar (InSAR) and GPS data collected from a network of continuous GPS receivers installed on the caldera complex. Observations from 1993-2010 using the ERS and Envisat satellites show subsidence on the Kameni islands, which can be interpreted either as loading by recent lava flows or degassing of a shallow magma body. The onset of the unrest was marked by an increase in the rate of micro-seismic activity, beginning in January 2011. At the same time, the coordinates of continuous GPS stations operating on Santorini began to deviate from their longer-term average velocities. To model the temporal evolution of melt supply to the shallow chamber, we have used Envisat and TerraSAR-X data since March 2011, as well as cGPS data since June 2010. We apply a joint inversion technique to convert deformation measurements into sub-surface volume change by treating the displacements as arising from a pressure increase at depth within an elastic crust. We present the best-fit parameters for the spherical source and the variation in volume change associated with a shallow magmatic intrusion during the 2011-2012 period of unrest. Our results indicate that melt is supplied to the shallow chamber as infrequent high-flux batches and that the duration of each intrusive event is short in comparison with the

  11. Integration of InSAR and GIS in the Study of Surface Faults Caused by Subsidence-Creep-Fault Processes in Celaya, Guanajuato, Mexico (United States)

    Avila-Olivera, Jorge A.; Farina, Paolo; Garduño-Monroy, Victor H.


    In Celaya city, Subsidence-Creep-Fault Processes (SCFP) began to become visible at the beginning of the 1980s with the sprouting of the crackings that gave rise to the surface faults "Oriente" and "Poniente". At the present time, the city is being affected by five surface faults that display a preferential NNW-SSE direction, parallel to the regional faulting system "Taxco-San Miguel de Allende". In order to study the SCFP in the city, the first step was to obtain a map of surface faults, by integrating in a GIS field survey and an urban city plan. The following step was to create a map of the current phreatic level decline in city with the information of deep wells and using the "kriging" method in order to obtain a continuous surface. Finally the interferograms maps resulted of an InSAR analysis of 9 SAR images covering the time interval between July 12 of 2003 and May 27 of 2006 were integrated to a GIS. All the maps generated, show how the surface faults divide the city from North to South, in two zones that behave in a different way. The difference of the phreatic level decline between these two zones is 60 m; and the InSAR study revealed that the Western zone practically remains stable, while sinkings between the surface faults "Oriente" and "Universidad Pedagógica" are present, as well as in portions NE and SE of the city, all of these sinkings between 7 and 10 cm/year.

  12. Coseismic Deformation Field and Source Modelling for the August 24, 2016 Amatrice Event from the Inversion of InSAR and GPS Data (United States)

    Salvi, S.; Cheloni, D.; Pezzo, G.; Tolomei, C.; Bignami, C.; Atzori, S.; Antonioli, A.; Trasatti, E.; Stramondo, S.; Devoti, R.; Riguzzi, F.; Serpelloni, E.; Pietrantonio, G.; Anzidei, M.; D'Agostino, N.; Avallone, A.; Cecere, G.; Esposito, A.; Sepe, V.; Galvani, A.; Selvaggi, G.; Giuliani, R.; Mattone, M.; Calcaterra, S.; Gambino, P.


    On August 24, 2016 a Mw 6.0 earthquake struck the Central Apennines, between the towns of Norcia and Amatrice. The epicentre was located near the village of Accumoli. Twenty hours later the first SAR interferogram was obtained from ALOS-2 data and clearly showed the co-seismic deformation field. In the following days, the InSAR analysis benefited from further data, also from Sentinel-1A and B, and COSMO-SkyMed. All displacement maps showed very similar patterns, with maximum displacement values of 20 cm away from the satellites. We will present the co-seismic deformation measurements and the source model obtained by inverting InSAR and GPS data ( 100 continuous and survey-mode GPS measurements). According to the two-lobe pattern, we modeled the data with two independent fault segments, coming up with very similar geometries and mechanisms. This suggests that the rupture occurred on a single structure, oriented NNW-SSE, dipping W at 45°-55°, extending about 18 km between the towns of Norcia and Amatrice. The slip distribution shows a 1.4 maximum in the north, at 5 km depth, and another large slip concentration ( 1m) in the south at 3 km depth, with an overall "geodetic" magnitude 6.2. We also computed the Coulomb Failure Function (CFF) on six nearby faults, obtained from the DISS Working Group, 2010, database. An increase of the CFF is only visible on two fault planes aligned with the Amatrice fault. These results were repeatedly updated during the emergency, as the new data became available. The information was then summarized in synthetic reports and disseminated to the Italian Civil Protection to support the decision making process. This result was obtained thanks to the free and fast data access procedures made available by initiatives as the CEOS Seismic Pilot, the ALOS 2 scientific AO, the EU Copernicus program.

  13. Monitoring water level using Sentinel-1 Interferometric Synthetic Aperture Radar (InSAR) images (United States)

    Stavroulaki, Eleni; Alexakis, Dimitrios D.; Tsanis, Ioannis K.


    Interferometric Synthetic Aperture Radar (SAR) methodology can successfully detect phase variations related to water level changes and produce corresponding water level maps. Two lakes located in Western Crete, Greece, namely Lake Kournas and Lake Agia were used as case studies to study water level change with means of SAR interferometry. The change of the water surface in the lake is examined over a period of two years, 2015-2016 using Sentinel 1 IW mode images and in situ water level data. Initially, all the SAR images were preprocessed in terms of atmospheric and radiometric corrections. Various interferograms were developed to study the multi-temporal regime of water level in both lakes. Optical satellite sensor data (Landsat 8) were used to study the vegetation regime and how this affect the interferogram processing. The results denoted the fact that the combination of SAR backscattering intensity and unwrapped phase water level data can provide additional insight into hydrological state. It is also shown that integrated analysis of the backscattering mechanism and interferometric characteristics can considerably enhance the reliability of the water-level retrieval scheme and optimize the capture of hydrological patterns spatial distribution. Keywords: Sentinel-1, interferogram, water level, Backscattering

  14. Application of InSAR to detection of localized subsidence and its effects on flood protection infrastructure in the New Orleans area (United States)

    Jones, Cathleen; Blom, Ronald; Latini, Daniele


    The vulnerability of the United States Gulf of Mexico coast to inundation has received increasing attention in the years since hurricanes Katrina and Rita. Flood protection is a challenge throughout the area, but the population density and cumulative effect of historic subsidence makes it particularly difficult in the New Orleans area. Analysis of historical and continuing geodetic measurements identifies a surprising degree of complexity in subsidence (Dokka 2011), including regions that are subsiding at rates faster than those considered during planning for hurricane protection and for coastal restoration projects. Improved measurements are possible through combining traditional single point, precise geodetic data with interferometric synthetic aperture radar (InSAR) observations for to obtain geographically dense constraints on surface deformation. The Gulf Coast environment is very challenging for InSAR techniques, especially with systems not designed for interferometry. We are applying pair-wise InSAR to longer wavelength (L-band, 24 cm) synthetic aperture radar data acquired with the airborne UAVSAR instrument ( to detect localized change impacting flood protection infrastructure in the New Orleans area during the period from 2009 - 2013. Because aircraft motion creates large-scale image artifacts across the scene, we focus on localized areas on and near flood protection infrastructure to identify anomalous change relative to the surrounding area indicative of subsidence, structural deformation, and/or seepage (Jones et al., 2011) to identify areas where problems exist. C-band and particularly X-band radar returns decorrelate over short time periods in rural or less urbanized areas and are more sensitive to atmospheric affects, necessitating more elaborate analysis techniques or, at least, a strict limit on the temporal baseline. The new generation of spaceborne X-band SAR acquisitions ensure relatively high frequency of

  15. Large-scale InSAR monitoring of permafrost freeze-thaw cycles on the Tibetan Plateau (United States)

    Daout, Simon; Doin, Marie-Pierre; Peltzer, Gilles; Socquet, Anne; Lasserre, Cécile


    Multitemporal interferometric synthetic aperture radar (InSAR) observations are used to characterize spatial variations of the permafrost active layer and its temporal evolution in Northwestern Tibet. We develop a method to enhance InSAR performances for such difficult terrain conditions and construct an 8 year timeline of the surface deformation over a 60,000 km2 area. The ground movement induced by the active layer's response to climate forcing is limited to Cenozoic sedimentary basins and is spatially variable in both its seasonal amplitude (2.5-12 mm) and multiannual trend (-2 to 3 mm/yr). A degree-day integrated model adjusted to the data indicates that subsidence occurs when the surface temperature exceeds zero (May to October) over areas where seasonal movements are large (>8 mm). The period of subsidence is delayed by 1-2 months over areas where smaller seasonal movements are observed, suggesting an unsaturated soil where water occurs in the deeper part of the active layer.

  16. InSAR observations of aseismic slip associated with an earthquake swarm in the Columbia River flood basalts (United States)

    Wicks, C.; Thelen, W.; Weaver, C.; Gomberg, J.; Rohay, A.; Bodin, P.


    In 2009 a swarm of small shallow earthquakes occurred within the basalt flows of the Columbia River Basalt Group (CRBG). The swarm occurred within a dense seismic network in the U.S. Department of Energys Hanford Site. Data from the seismic network along with interferometric synthetic aperture radar (InSAR) data from the European Space Agencys (ESA) ENVISAT satellite provide insight into the nature of the swarm. By modeling the InSAR deformation data we constructed a model that consists of a shallow thrust fault and a near horizontal fault. We suggest that the near horizontal lying fault is a bedding-plane fault located between basalt flows. The geodetic moment of the modeled fault system is about eight times the cumulative seismic moment of the swarm. Precise location estimates of the swarm earthquakes indicate that the area of highest slip on the thrust fault, ???70mm of slip less than ???0.5km depth, was not located within the swarm cluster. Most of the slip on the faults appears to have progressed aseismically and we suggest that interbed sediments play a central role in the slip process. Copyright 2011 by the American Geophysical Union.

  17. InSAR observations of aseismic slip associated with an earthquake swarm in the Columbia River flood basalts (United States)

    Wicks, Charles; Thelen, Weston; Weaver, Craig; Gomberg, Joan; Rohay, Alan; Bodin, Paul


    In 2009 a swarm of small shallow earthquakes occurred within the basalt flows of the Columbia River Basalt Group (CRBG). The swarm occurred within a dense seismic network in the U.S. Department of Energy's Hanford Site. Data from the seismic network along with interferometric synthetic aperture radar (InSAR) data from the European Space Agency's (ESA) ENVISAT satellite provide insight into the nature of the swarm. By modeling the InSAR deformation data we constructed a model that consists of a shallow thrust fault and a near horizontal fault. We suggest that the near horizontal lying fault is a bedding-plane fault located between basalt flows. The geodetic moment of the modeled fault system is about eight times the cumulative seismic moment of the swarm. Precise location estimates of the swarm earthquakes indicate that the area of highest slip on the thrust fault, ˜70 mm of slip less than ˜0.5 km depth, was not located within the swarm cluster. Most of the slip on the faults appears to have progressed aseismically and we suggest that interbed sediments play a central role in the slip process.

  18. A prototype of an automated high resolution InSAR volcano-monitoring system in the MED-SUV project (United States)

    Chowdhury, Tanvir A.; Minet, Christian; Fritz, Thomas


    Volcanic processes which produce a variety of geological and hydrological hazards are difficult to predict and capable of triggering natural disasters on regional to global scales. Therefore it is important to monitor volcano continuously and with a high spatial and temporal sampling rate. The monitoring of active volcanoes requires the reliable measurement of surface deformation before, during and after volcanic activities and it helps for the better understanding and modelling of the involved geophysical processes. Space-borne synthetic aperture radar (SAR) interferometry (InSAR), persistent scatterer interferometry (PSI) and small baseline subset algorithm (SBAS) provide a powerful tool for observing the eruptive activities and measuring the surface changes of millimetre accuracy. All the mentioned techniques with deformation time series extraction address the challenges by exploiting medium to large SAR image stacks. The process of selecting, ordering, downloading, storing, logging, extracting and preparing the data for processing is very time consuming has to be done manually for every single data-stack. In many cases it is even an iterative process which has to be done regularly and continuously. Therefore, data processing becomes slow which causes significant delays in data delivery. The SAR Satellite based High Resolution Data Acquisition System, which will be developed at DLR, will automate this entire time consuming tasks and allows an operational volcano monitoring system. Every 24 hours the system runs for searching new acquired scene over the volcanoes and keeps track of the data orders, log the status and download the provided data via ftp-transfer including E-Mail alert. Furthermore, the system will deliver specified reports and maps to a database for review and use by specialists. The user interaction will be minimized and iterative processes will be totally avoided. In this presentation, a prototype of SAR Satellite based High Resolution Data

  19. Gravity and InSAR remote sensing of groundwater usage in the Sahel and Horn of Africa (United States)

    Neely, W.; Borsa, A. A.; Burney, J. A.; Devlin, K.


    Changes in the Earth's climatic systems influence agro-ecological conditions on local, regional, and global scales. With the world's highest population growth rate, sub-Saharan Africa faces particularly acute concerns regarding food security and resource management. Historical sources of surface water for agricultural production may become less reliable and/or limited with increased climate variability, and African countries have already begun to depend on more stable sources of groundwater. Expected increases in groundwater usage pose questions about the sustainability of current agricultural practices, which require new sources of information to answer. Due to the logistics and costs to implement in situ networks to monitor regional water security, current remote sensing missions offer an affordable alternative. The Gravity Recovery and Climate Experiment (GRACE) has proven to be effective in quantifying changes in terrestrial water storage (TWS) at the regional scale using near-monthly gravity measurements from orbit. Using over a decade of measurements, we estimate TWS anomalies in Niger and Ethiopia. These anomalies offer a proxy for hydrological stressing, indicating potential targets for additional analysis. We use independent, but complementary, estimates of surface displacements from Interferometric Synthetic Aperture Radar (InSAR) to provide information on local groundwater withdrawal. Using data from ESA's Sentinel 1 mission and JAXA's Advanced Land Observing Satellite (ALOS) missions, we characterize the surface deformation over the past decade in regions of active groundwater pumping using the Small Baseline Subset (SBAS) technique. In particular, we investigate ties of ground motion to known agricultural/industrial land usage near Niamey, Niger and Eastern Oromia, Ethiopia to better understand how human activity affects available groundwater resources.

  20. Integration and interpretation of InSAR deformation products from the Sentinel-1 constellation - experiences from the InSARap project (United States)

    Dehls, John F.; Larsen, Yngvar; Marinkovic, Petar; Perski, Zbigniew


    The Sentinel-1 mission has been in operational mode for more than two years, and with the successful commissioning of S1B in Sep 2016, the constellation is now complete. While the InSAR community initially faced many processing challenges due to the introduction of the new TOPS mode, these issues can by now considered resolved. However, truly operational workflows are still to be designed and deployed, and there are a number of integration and interpretation challenges that need to be addressed to achieve operational processing of 6-day revisit InSAR data. In this contribution, we will focus mainly on the integration and interpretation of InSAR products in scientific workflows, rather than on algorithmic details. We will motivate discussion with results obtained from selected pilot sites within the ESA SEOM InSARap project. The sites cover a large part of the application domain for InSAR - "from decimeter to millimeter". Specifically, landslide and corner reflector validation test sites in Norway and Poland will be discussed. The results will serve as basis for a discussion on how to communicate and streamline a portfolio of subsidence products to end users, which is a challenge in itself. We will conclude with a discussion on remaining open questions regarding how we as a community can address these issues to a wider audience.

  1. Surface motion of active rock glaciers in the Sierra Nevada, California, USA: inventory and a case study using InSAR (United States)

    L. Liu; C.I. Millar; R.D. Westfall; H.A. Zebker


    Despite the abundance of rock glaciers in the Sierra Nevada of California, USA, few efforts have been made to measure their surface flow. Here we use the interferometric synthetic aperture radar (InSAR) technique to compile a~benchmark inventory describing the kinematic state of 59 active rock glaciers in this region. Statistically, these rock glaciers moved at...

  2. Localized landslide risk assessment with multi pass L band DInSAR analysis (United States)

    Yun, HyeWon; Rack Kim, Jung; Lin, Shih-Yuan; Choi, YunSoo


    In terms of data availability and error correction, landslide forecasting by Differential Interferometric SAR (DInSAR) analysis is not easy task. Especially, the landslides by the anthropogenic construction activities frequently occurred in the localized cutting side of mountainous area. In such circumstances, it is difficult to attain sufficient enough accuracy because of the external factors inducing the error component in electromagnetic wave propagation. For instance, the local climate characteristics such as orographic effect and the proximity to water source can produce the significant anomalies in the water vapor distribution and consequently result in the error components of InSAR phase angle measurements. Moreover the high altitude parts of target area cause the stratified tropospheric delay error in DInSAR measurement. The other obstacle in DInSAR observation over the potential landside site is the vegetation canopy which causes the decorrelation of InSAR phase. Thus rather than C band sensor such as ENVISAT, ERS and RADARSAT, DInSAR analysis with L band ALOS PLASAR is more recommendable. Together with the introduction of L band DInSAR analysis, the improved DInSAR technique to cope all above obstacles is necessary. Thus we employed two approaches i.e. StaMPS/MTI (Stanford Method for Persistent Scatterers/Multi-Temporal InSAR, Hopper et al., 2007) which was newly developed for extracting the reliable deformation values through time series analysis and two pass DInSAR with the error term compensation based on the external weather information in this study. Since the water vapor observation from spaceborne radiometer is not feasible by the temporal gap in this case, the quantities from weather Research Forecasting (WRF) with 1 km spatial resolution was used to address the atmospheric phase error in two pass DInSAR analysis. Also it was observed that base DEM offset with time dependent perpendicular baselines of InSAR time series produce a significant error

  3. Detection of Slope Instabilities Along the National Road 7, Mendoza Province, Argentina, Using Multi-Temporal InSAR (United States)

    Michoud, Clément; Derron, Marc-Henri; Baumann, Valérie; Jaboyedoff, Michel; Rune Lauknes, Tom


    About 2'230 vehicles per day pass through the National Road 7 that link Buenos Aires to Santiago de Chile, crossing Andes Cordillera. This extremely important corridor, being the most important land pass between Argentina and Chile, is exposed to numerous natural hazards, such as snow avalanches, rockfalls and debris flows and remains closed by natural hazards several days per year. This goal of this study is to perform a regional mapping of geohazard susceptibilities along the Road 7 corridor, as started by Baumann et al. (2005), using modern remote sensing and numerical approaches with field checking. The area of interest is located in the Mendoza Province, between the villages Potrerillos and Las Cuevas near the Chilean border. The diversity of soil and rock conditions, the active geomorphological processes associated to post-glacial decompression, seasonal freeze and thaw and severe storms along the road corridor, increase the risk to natural hazard. With the support of the European Space Agency (ESA Category-1 Project 7154), we have in this study processed a large number of ERS and Envisat ASAR scenes, covering the period from 1995 to 2000. We applied both the small-baseline (SB) and the persistent scatterer (PSI) multi-temporal interferometric SAR (InSAR) techniques. The study area contains sparse vegetation, and the SB InSAR method is therefore well suited to map the area containing mainly distributed scatterers. Furthermore, PSI algorithms are also used for comparison for selected landslides in the inventory. Both approaches show a relatively good coherence within mountain areas, which is a good point for the landslide detections along the road. Indeed, the authors identified several large slope instabilities even active scree deposits. This inventory is finally compared with field observations and with existing susceptibility maps regarding snow avalanches, debris-flows and rockfalls. The final objective of this project is to develop a risk strategy that

  4. InSAR Detection and Field Evidence for Thermokarst after a Tundra Wildfire, Using ALOS-PALSAR

    Directory of Open Access Journals (Sweden)

    Go Iwahana


    Full Text Available Thermokarst is the process of ground subsidence caused by either the thawing of ice-rich permafrost or the melting of massive ground ice. The consequences of permafrost degradation associated with thermokarst for surface ecology, landscape evolution, and hydrological processes have been of great scientific interest and social concern. Part of a tundra patch affected by wildfire in northern Alaska (27.5 km2 was investigated here, using remote sensing and in situ surveys to quantify and understand permafrost thaw dynamics after surface disturbances. A two-pass differential InSAR technique using L-band ALOS-PALSAR has been shown capable of capturing thermokarst subsidence triggered by a tundra fire at a spatial resolution of tens of meters, with supporting evidence from field data and optical satellite images. We have introduced a calibration procedure, comparing burned and unburned areas for InSAR subsidence signals, to remove the noise due to seasonal surface movement. In the first year after the fire, an average subsidence rate of 6.2 cm/year (vertical was measured. Subsidence in the burned area continued over the following two years, with decreased rates. The mean rate of subsidence observed in our interferograms (from 24 July 2008 to 14 September 2010 was 3.3 cm/year, a value comparable to that estimated from field surveys at two plots on average (2.2 cm/year for the six years after the fire. These results suggest that this InSAR-measured ground subsidence is caused by the development of thermokarst, a thawing process supported by surface change observations from high-resolution optical images and in situ ground level surveys.

  5. L band InSAR sudy on the Ganos section of the North Anatolian Fault Zone (NAFZ) (United States)

    de Michele, Marcello


    The North Anatolian Fault (NAF), with a total length of about 1500 km, is one of the most active right-lateral strike-slip faults in the world. It defines the tectonic boundary between the Anatolian Plate and the Eurasian Plate in northern Turkey, accommodating ~14-30 mm/yr of relative plate motion between the two plates (fig. 1). The Gazikoy-Saros segment (the Ganos fault, GF) is the onshore segment of the northern strand of the NAF between the Marmara Sea and the Gulf of Saros. It was last ruptured in 1912 with a Ms=7.4 earthquake that broke the entire inland segment of the fault, a length of about 50 km, and produced a right-lateral strike-slip component of at least 3 m. Other large historical earthquakes that have been attributed to the Ganos fault occurred in A.D. 824, 1343, 1509 and 1766 (e. g. Reilinger et al., 2000; Meade et al., 2002; Motagh et al., 2007; Janssen et al., 2009; Megraoui et al., 2012 ; Ersen Aksoy et al., 2010). The GF forms a 45 km long linear fault system and represents the link between the northern strand of the NAFZ in the Sea of Marmara and the North Aegean Trough where slip partitioning results in branching of the fault zone. The present study aims at showing the results retrieved from L band Interferometric Syntethic Aperture Radar (InSAR) measurements for the monitoring of Crustal Deformation in the Anatolian Fault Zone in the frame of the MARMARA SUPERSITE PROJECT "MARSITE" on the Ganos section of the North Anatolian fault zone. We processed SAR data made available through the CAT-1 ESA (European Space Agency) archives, acquired by the L-band radar sensor ALOS PALSAR between 2007 and 2011. The aim of this exercise is to test L-band capabilities to map the spatial and temporal evolution of the present-day crustal deformation phenomena affecting the Ganos section of the NAFZ with high level of spatial details. The goal of this task is to assess whether InSAR L-Band data can be useful to evaluate the long-term behavior of active faults

  6. On the Use of the ISBAS Acronym in InSAR Applications. Comment on Vajedian, S.; Motagh, M.; Nilfouroushan, F. StaMPS Improvement for Deformation Analysis in Mountainous Regions: Implications for the Damavand Volcano and Mosha Fault in Alborz. Remote Sens. 2015, 7, 8323–8347

    Directory of Open Access Journals (Sweden)

    Andrew Sowter


    Full Text Available Vajedian et al. [1] present an improved method for the derivation of deformation parameters using satellite Interferometric Synthetic Aperture Radar (InSAR data. The method is a modification of the Small Baseline Subset (SBAS method as implemented in the StaMPS (Stanford Method for Persistent Scatterers software. The modification includes many steps including the filtering of the differential interferograms, integration with GPS data and advanced phase unwrapping “to overcome a lot of short- and long-wavelength artifacts that are clearly visible in StaMPS results” (cf. [1], p. 8331. The authors refer to this new approach as the Improved SBAS, or ISBAS, method. [...

  7. Quantifying changes in land-surface height in bioenergy palm oil plantations (Sumatra) using InSAR time series. (United States)

    Zhou, Zhiwei; Waldron, Susan; Li, Zhenhong


    Tropical peatlands in Southeast Asia cover ~ 439,238 km sq. and represent ~77 % of global tropical peatland carbon stores and ~11 % of global peatland area. These landscapes are substantial C stores accounting for ~17-19 % of the global peat C pool (Page et al., 2010). Within southeast Asia, Indonesian peatlands hold most C (57.4 Pg, 65 %), followed by Malaysia (9.1 Pg, 10 %). In recent decades the drive to use these soils for agriculture and often the palm oil biogenergy crop, has driven fire-clearing, deforestation and drainage of these carbon landscapes. The drainage can lead to respiration of the soil carbon store and subsidence of the peatland (Hooijer et al., 2012), reducing their strength as a current C store and their capacity for future soil C storage. Using field-based surveying to monitor changes in the past peatland surface height, and over the large areas typical of commercial agricultural palm oil plantations, is challenging such that measurements are more likely to describe a small area and be only a snapshot in time. Upscaling and understanding the rate of change in surface height through time may be overcome using remote sensing approaches. Here we present data on the change in peatland surface height in Indonesia palm oil plantations, detected using the Interferometry Synthetic Aperture Radar (InSAR) Small BAseline Set (SBAS) approach (Berardino et al., 2002). Using data from July 2007 to January 2011, we have generated a map of the rate of change of mean height, and time series of change in surface height for several plantation areas. To do this we used two independent ALOS L-band tracks SAR images, as there is a lack of ground data for validation, coherence in output provides confidence the results are representative. Our analysis to date shows that in drained and planted palm oil areas: 1) the rate of change in surface height (decrease) can vary; 2) the decrease in surface height can be up to 5 cm/year; 3) the largest decrease in surface height

  8. Coseismic Faults and Crust Deformation Accompanied the 2008 Wenchuan Earthquake, China by Field Investigation and InSAR Interferogram (United States)

    Hao, K.; Si, H.; Fujiwara, H.; Ozawa, T.


    The devastated Mw 7.9 Wenchuan earthquake occurred along the steep eastern margin of the Tibetan plateau in Sichuan, China, on 12 May 2008. Over 86,592 people were dead or missing, 374159 injured, and more than 4.8 million homeless. The ruptures possibly occurred over a length of 285 km along the northeast striking Longmen Shan (LMS) thrust belt. In order to study the oversized fault ruptures, existing active faults related and relationships with the damages caused, we conducted field investigations during 4-15 June and 3-9 October 2008, covered about 140km length of LMS faults, including Beichuan(BC), Anxian(AC), Mianzhu, Shifang, Pengzhou, Dujiangyan, Yingxiu (YX) and Wenchuan. On the field investigation we found coseismic surface faults along several profiles perpendicular to the LMS faults. The coseismic surface faults we discovered were at Leigu(L), Hanwang(H), Yinghua(Y), Bailu(BL), Xiaoyudong(X), and Baiyunding (BYD). Of them the maximum vertical displacement reached 4.6m at L, Beichuan County. The uplifting displacements dominated in the southwestern section of the rupture. Moreover, the northwest-striking left-lateral fault was found with horizontal displacement of 2.8m, and vertical of 1.5m as well, at X, Pengzhou City. The left-lateral fault, inversely under-controlled movement of right- lateral fault in the area, showed the complexity of the fault movements. The field results showed the coseismic surface ruptures locally while the overall faults movements and Crust deformation could be understood by the Interferometric SAR(InSAR) technique (NIED, 2008) using data from the Phased Array L-band SAR sensor (PALSAR) equipped on Advanced Land Observing Satellite (ALOS). The larger deformation zones detected by InSAR interferogram occurred with a width of ~30 km in southwestern section, and of ~10km in northeastern section of LMS faults. In the southwestern section, the deformation zone occurred mostly within the existing active faults zones: Guanxian

  9. InSAR observations of strain accumulation and fault creep along the Chaman Fault system, Pakistan and Afghanistan (United States)

    Fattahi, Heresh; Amelung, Falk


    We use 2004-2011 Envisat synthetic aperture radar imagery and InSAR time series methods to estimate the contemporary rates of strain accumulation in the Chaman Fault system in Pakistan and Afghanistan. At 29 N we find long-term slip rates of 16 ± 2.3 mm/yr for the Ghazaband Fault and of 8 ± 3.1 mm/yr for the Chaman Fault. This makes the Ghazaband Fault one of the most hazardous faults of the plate boundary zone. We further identify a 340 km long segment displaying aseismic surface creep along the Chaman Fault, with maximum surface creep rate of 8.1 ± 2 mm/yr. The observation that the Chaman Fault accommodates only 30% of the relative plate motion between India and Eurasia implies that the remainder is accommodated south and east of the Katawaz block microplate.

  10. InSAR Observations Of Crustal Deformation Mechanics In The Interior Of The Puna Plateau Of The Southern Central Andes (United States)

    Eckelmann, Felix; Motagh, Mahdi; Bokhagen, Bodo; Strecker, Manfred


    Crustal deformation evidences in the orogenic interior of the Southern Central Andes at different time scales are observed by applying ENVISAT InSAR time series from 2005 - 2009 and differential GPS data taken in the study area of the palaeo-lake Salar de Pocitos (24.5°S, 67°W, 3650 m asl). Ongoing shortening in the region from the Tertiary to the present-day is indicated by an uplift of Quaternary palaeo-lake terraces of about 4 to 5m within the last 44ka as well as by the growth of an anticline in Tertiary sediments and the reactivation of the reverse-fault bounded Sierra de Macón, both with uplift rates of 2 - 5mm/a. In summary, this study emphasizes the diachronous and spatially disparate character of the tectonic regime at the Puna Plateau.

  11. Mitigation of atmospheric phase delays in InSAR data, with application to the eastern California shear zone (United States)

    Tymofyeyeva, Ekaterina; Fialko, Yuri


    We present a method for estimating radar phase delays due to propagation through the troposphere and the ionosphere based on the averaging of redundant interferograms that share a common scene. Estimated atmospheric contributions can then be subtracted from the radar interferograms to improve measurements of surface deformation. Inversions using synthetic data demonstrate that this procedure can considerably reduce scatter in the time series of the line-of-sight displacements. We demonstrate the feasibility of this method by comparing the interferometric synthetic aperture radar (InSAR) time series derived from ERS-1/2 and Envisat data to continuous Global Positioning System data from eastern California. We also present results from several sites in the eastern California shear zone where anomalous deformation has been reported by previous studies, including the Blackwater fault, the Hunter Mountain fault, and the Coso geothermal plant.

  12. On the use of InSAR technology to assess land subsidence in Jakarta coastal flood plain (United States)

    Koudogbo, Fifame; Duro, Javier; Garcia Robles, Javier; Arnaud, Alain; Abidin, Hasanuddin Z.


    Jakarta is the capital of Indonesia and is home to approximately 10 million people on the coast of the Java Sea. It is situated on the northern coastal alluvial plane of Java which shares boundaries with West Java Province in the south and in the east, and with Banten Province in the west. The Capital District of Jakarta (DKI) sits in the lowest lying areas of the basin. Its topography varies, with the northern part just meters above current sea level and lying on a flood plain. Subsequently, this portion of the city frequently floods. The southern part of the city is hilly. Thirteen major rivers flow through Jakarta to the Java Sea. The Ciliwung River is the most significant river and divides the city West to East. In the last three decades, urban growing of Jakarta has been very fast in sectors as industry, trade, transportation, real estate, among others. This exponential development has caused several environmental issues; land subsidence is one of them. Subsidence in Jakarta has been known since the early part of the 20th century. It is mainly due to groundwater extraction, the fast development (construction load), soil natural consolidation and tectonics. Evidence of land subsidence exists through monitoring with GPS, level surveys and InSAR investigations. InSAR states for "Interferometric Synthetic Aperture Radar". Its principle is based on comparing the distance between the satellite and the ground in consecutive satellite passes over the same area on the Earth's surface. Radar satellites images record, with very high precision, the distance travelled by the radar signal that is emitted by the satellite is registered. When this distance is compared through time, InSAR technology can provide highly accurate ground deformation measurements. ALTAMIRA INFORMATION, company specialized in ground motion monitoring, has developed GlobalSARTM, which combines several processing techniques and algorithms based on InSAR technology, to achieve ground motion

  13. Earthquake rupture properties of the 2016 Kumamoto earthquake foreshocks ( M j 6.5 and M j 6.4) revealed by conventional and multiple-aperture InSAR (United States)

    Kobayashi, Tomokazu


    By applying conventional cross-track InSAR and multiple-aperture InSAR (MAI) techniques with ALOS-2 SAR data to foreshocks of the 2016 Kumamoto earthquake, ground displacement fields in range (line-of-sight) and azimuth components have been successfully mapped. The most concentrated crustal deformation with ground displacement exceeding 15 cm is located on the western side of the Hinagu fault zone. A locally distributed displacement which appears along the strike of the Futagawa fault can be identified in and around Mashiki town, suggesting that a different local fault slip also contributed toward foreshocks. Inverting InSAR, MAI, and GNSS data, distributed slip models are obtained that show almost pure right-lateral fault motion on a plane dipping west by 80° for the Hinagu fault and almost pure normal fault motion on a plane dipping south by 70° for the local fault beneath Mashiki town. The slip on the Hinagu fault reaches around the junction of the Hinagu and Futagawa faults. The slip in the north significantly extends down to around 10 km depth, while in the south the slip is concentrated near the ground surface, perhaps corresponding to the M j 6.5 and the M j 6.4 events, respectively. The focal mechanism of the distributed slip model for the Hinagu fault alone shows pure right-lateral motion, which is inconsistent with the seismically estimated mechanism that includes a significant non-double couple component. On the other hand, when taking the contribution of normal fault motion into account, the focal mechanism appears similar to that of the seismic analysis. This result may suggest that local fault motion occurred just beneath Mashiki town, simultaneously with the M j 6.5 event, thereby increasing the degree of damage to the town.[Figure not available: see fulltext.

  14. Determination of The Water Catchment Area in Semarang City Using a Combination of Object Based Image Analysis (OBIA) Classification, InSAR and Geographic Information System (GIS) Methods Based On a High-Resolution SPOT 6 Image and Radar Imagery (United States)

    Prasetyo, Yudo; Ardi Gunawan, Setyo; Maksum, Zia Ul


    Semarang is the biggest city in central Java-Indonesia which has a rapid and massive infrastructure development nowadays. In order to control water resources and flood, the local goverment has been built east and west flood canal in Kaligarang and West Semarang River. One of main problem in Semarang city is the lack of fresh water in dry season because ground water is not rechargeable well. Rechargeable groundwater ability depends on underground water recharge rate and catchment area condition. The objective of the study is to determine condition and classification of water catchment area in Semarang city. The catchment area conditions will be determine by five parameters as follows soil type, land use, slope, ground water potential and rainfall intensity. In this study, we use three methods approach to solve the problem which is segmentation classification to acquire land use classification from high resolution imagery using nearest neighborhood algorithm, Interferometric Synthetic Aperture Radar (SAR) to derive DTM from SAR Imagery and multi criteria weighting and spatial analysis using GIS method. There are three types optical image (ALOS PRISM, SPOT-6 and ALOS PALSAR) to calculate water catchment area condition in Semarang city. For final result, this research will divide the water catchment into six criteria as follows good, naturally normal, early critical, a little bit critical, critical and very critical condition. The result shows that water catchment area condition is in an early critical condition around 2607,523 Ha (33,17 %), naturally normal condition around 1507,674 Ha (19,18 %), a little bit critical condition around 1452,931 Ha (18,48 %), good with 1157,04 Ha (14,72 %), critical with 1058,639 Ha (13,47 %) and very critical with 75,0387 Ha (0,95 %). The distribution of water catchment area conditions in West and East Flood Canal have an irreguler pattern. In northern area of watershed consists of begin to critical, naturally normal and good condition

  15. Correcting atmospheric effects on InSAR with MERIS water vapour data and elevation-dependent interpolation model

    KAUST Repository

    Li, Z. W.


    The propagation delay when radar signals travel from the troposphere has been one of the major limitations for the applications of high precision repeat-pass Interferometric Synthetic Aperture Radar (InSAR). In this paper, we first present an elevation-dependent atmospheric correction model for Advanced Synthetic Aperture Radar (ASAR—the instrument aboard the ENVISAT satellite) interferograms with Medium Resolution Imaging Spectrometer (MERIS) integrated water vapour (IWV) data. Then, using four ASAR interferometric pairs over Southern California as examples, we conduct the atmospheric correction experiments with cloud-free MERIS IWV data. The results show that after the correction the rms differences between InSAR and GPS have reduced by 69.6 per cent, 29 per cent, 31.8 per cent and 23.3 per cent, respectively for the four selected interferograms, with an average improvement of 38.4 per cent. Most importantly, after the correction, six distinct deformation areas have been identified, that is, Long Beach–Santa Ana Basin, Pomona–Ontario, San Bernardino and Elsinore basin, with the deformation velocities along the radar line-of-sight (LOS) direction ranging from −20 mm yr−1 to −30 mm yr−1 and on average around −25 mm yr−1, and Santa Fe Springs and Wilmington, with a slightly low deformation rate of about −10 mm yr−1 along LOS. Finally, through the method of stacking, we generate a mean deformation velocity map of Los Angeles over a period of 5 yr. The deformation is quite consistent with the historical deformation of the area. Thus, using the cloud-free MERIS IWV data correcting synchronized ASAR interferograms can significantly reduce the atmospheric effects in the interferograms and further better capture the ground deformation and other geophysical signals.

  16. Sustained Water Changes in California during Drought and Heavy Precipitation Inferred from GPS, InSAR, and GRACE (United States)

    Argus, D. F.; Fu, Y.; Landerer, F. W.; Wiese, D. N.; Farr, T. G.; Liu, Z.; Thomas, B. F.; Famiglietti, J. S.


    About 1200 GPS sites in the westernmost United States are used to weigh changes in surface water as a function of location from 2006 to 2015. The effect of known changes in water in artificial reservoirs is removed, allowing changes in the total of snow, soil moisture, and mountain fracture groundwater to be inferred from GPS. In this study water changes inferred from GPS are placed into the context of complementary InSAR and GRACE data. The southern Central Valley (the San Joaquin Valley and Tulare Basin) is subsiding at spectacular rates of 0.01 m/yr to 0.2 m/yr in response to groundwater management. We construct an elastic model of groundwater change of the southern Central Valley, using GRACE as the basis of total groundwater loss and InSAR to infer the lateral distribution of that groundwater loss. This elastic model of Central Valley groundwater loss is removed from the GPS displacements. Because snow in California is insignificant in October, and because changes in soil moisture between successive autumns are small, we can infer changes in Sierra Nevada mountain fracture groundwater to be: -19 km3 during drought from 2006 to 2009, +35 km3 during heavy precipitation from 2009 to 2011, and -38 km3 during drought from 2011 to 2014 (start and end times are all in October). We infer changes in Sierra Nevada mountain groundwater to be playing an important role in modulating Central Valley groundwater loss. Total water in the Sierra Nevada recovered by 16 km3 from October 2014 to April 2015, but water is being lost again in summer 2015.

  17. Co-seismic Slip Distribution of 2010 Darfield Mw 7.1 Earthquake Derived from InSAR Measurements (United States)

    Luo, X.; Sun, J.; Shen, Z.


    The New Zealand islands locating at the boundary between the Pacific and Australian plates, is one of the most seismically active regions in the world. However, the 2010 Darfield earthquake occurred on previously-unknown faults, which absorb only a minor portion of relative plate motion there. We attempt to obtain detailed information about fault geometry and rupture distribution of this event using InSAR data, the result will be useful in understanding tectonic process and seismic hazards of the region. We use ALOS PALSAR data from JAXA to derive SAR los interferograms associated with coseismic deformation of this earthquake. More than one evidence reveals that not only Greendale fault involved in this earthquake. Combining geological field survey observations with SAR displacement fringes, correlation, and range and azimuth offsets, we identify four faults slipped during coseismic rupture, of which seven segments are distinguished with various strikes and dip angles, as shown in the figure. Our inversion result shows that slip is concentrated in the upper 10 km depth. Slips along the Greendale fault (segments 1-4 in figure) are predominantly dextral with a maximum of up to 8 m. Fault segments 5 and 6 slipped reversely, with peaks of ~3 m and 3.8 m respectively. Slip on fault segment 7 is minor, no more than 1.8 m. We also compare the top 1 km slip along the Greendale fault with surface rupture distribution, and find very good agreement. The maximum surface slip is about 6 m, located about 26 km east of the west end of the fault surface rupture. The total seismic moment released equivalents to an Mw=7.1 event. Main features of InSAR data are well recovered, the residuals near the epicenter are less than 20 cm, confirming good data fitting of our fault slip model. The main data residuals are at footwall, possibly due to strong variation of deformation field revealed by complex interferogram fringes there. We also find that some displacements are not well explained

  18. Preliminary Study of a Millimeter Wave FMCW InSAR for UAS Indoor Navigation

    Directory of Open Access Journals (Sweden)

    Antonio F. Scannapieco


    Full Text Available Small autonomous unmanned aerial systems (UAS could be used for indoor inspection in emergency missions, such as damage assessment or the search for survivors in dangerous environments, e.g., power plants, underground railways, mines and industrial warehouses. Two basic functions are required to carry out these tasks, that is autonomous GPS-denied navigation with obstacle detection and high-resolution 3Dmapping with moving target detection. State-of-the-art sensors for UAS are very sensitive to environmental conditions and often fail in the case of poor visibility caused by dust, fog, smoke, flames or other factors that are met as nominal mission scenarios when operating indoors. This paper is a preliminary study concerning an innovative radar sensor based on the interferometric Synthetic Aperture Radar (SAR principle, which has the potential to satisfy stringent requirements set by indoor autonomous operation. An architectural solution based on a frequency-modulated continuous wave (FMCW scheme is proposed after a detailed analysis of existing compact and lightweight SAR. A preliminary system design is obtained, and the main imaging peculiarities of the novel sensor are discussed, demonstrating that high-resolution, high-quality observation of an assigned control volume can be achieved.

  19. Preliminary Study of a Millimeter Wave FMCW InSAR for UAS Indoor Navigation (United States)

    Scannapieco, Antonio F.; Renga, Alfredo; Moccia, Antonio


    Small autonomous unmanned aerial systems (UAS) could be used for indoor inspection in emergency missions, such as damage assessment or the search for survivors in dangerous environments, e.g., power plants, underground railways, mines and industrial warehouses. Two basic functions are required to carry out these tasks, that is autonomous GPS-denied navigation with obstacle detection and high-resolution 3D mapping with moving target detection. State-of-the-art sensors for UAS are very sensitive to environmental conditions and often fail in the case of poor visibility caused by dust, fog, smoke, flames or other factors that are met as nominal mission scenarios when operating indoors. This paper is a preliminary study concerning an innovative radar sensor based on the interferometric Synthetic Aperture Radar (SAR) principle, which has the potential to satisfy stringent requirements set by indoor autonomous operation. An architectural solution based on a frequency-modulated continuous wave (FMCW) scheme is proposed after a detailed analysis of existing compact and lightweight SAR. A preliminary system design is obtained, and the main imaging peculiarities of the novel sensor are discussed, demonstrating that high-resolution, high-quality observation of an assigned control volume can be achieved. PMID:25621606

  20. Preliminary study of a millimeter wave FMCW InSAR for UAS indoor navigation. (United States)

    Scannapieco, Antonio F; Renga, Alfredo; Moccia, Antonio


    Small autonomous unmanned aerial systems (UAS) could be used for indoor inspection in emergency missions, such as damage assessment or the search for survivors in dangerous environments, e.g., power plants, underground railways, mines and industrial warehouses. Two basic functions are required to carry out these tasks, that is autonomous GPS-denied navigation with obstacle detection and high-resolution 3Dmapping with moving target detection. State-of-the-art sensors for UAS are very sensitive to environmental conditions and often fail in the case of poor visibility caused by dust, fog, smoke, flames or other factors that are met as nominal mission scenarios when operating indoors. This paper is a preliminary study concerning an innovative radar sensor based on the interferometric Synthetic Aperture Radar (SAR) principle, which has the potential to satisfy stringent requirements set by indoor autonomous operation. An architectural solution based on a frequency-modulated continuous wave (FMCW) scheme is proposed after a detailed analysis of existing compact and lightweight SAR. A preliminary system design is obtained, and the main imaging peculiarities of the novel sensor are discussed, demonstrating that high-resolution, high-quality observation of an assigned control volume can be achieved.

  1. Analyses of surface deformation with SBAR InSAR method and its relationship with aquifer occurrence in Surabaya City, East Java, Indonesia (United States)

    Mochammad, Mushoddaq; Saepuloh, Asep


    Rapid development of Surabaya City requires space for industry and settlement. The city development is followed by increasing of water demand for various purposes. Large amount of groundwater extraction may cause ground subsidence. According to groundwater extraction, we tried to delineate the possibility of aquifer potential based on ground surface deformation using Interferometric Synthetic Aperture Radar (InSAR) and Electrical Resistivity methods. The InSAR is a method to estimate surface deformation in millimeter scale based on different phase of SAR data between acquisition times. In this paper, surface deformation combined with ground resistivity was used to analyse the potential of aquifer related to subsidence at Surabaya City, East Java, Indonesia. The Small Based Subset (SBAS) method was used to reduce phase delayed in the interferogram due to atmospheric condition. Based on the SBAS InSAR the deformation was detected at Surabaya City in January 2007 to February 2008. The largest and lowest deformation about 40 mm/year and about 0-10 mm/year were located in North to Southeastern and Western part of the city, respectively. The geodetic Global Positioning System (GPS) campaign in Surabaya confirmed that the detected deformation correlated with the ground subsidence with correlation coefficient about 0.96. To obtain the subsurface structures at subsidence zones, the Electrical Resistivity survey with Schlumberger configuration was performed in Surabaya city. According to the SBAS InSAR and subsurface resistivity, the subsidence around Pabeancantikan, Kenjeran, Simokerto and Tenggilismejoyo sub-districts agreed to high resistivity about 7-18 Ωm. The Sandstone of Kabuh and Pucangan formations in this area served as ground water aquifer which used by more than 200 wells. Ground water extraction probably triggered the subsidence at ground surface. The high resistivity at subsidence zones originated from high porosity of rocks served as aquifer with high

  2. An Automatic Mosaicking Algorithm for the Generation of a Large-Scale Forest Height Map Using Spaceborne Repeat-Pass InSAR Correlation Magnitude

    Directory of Open Access Journals (Sweden)

    Yang Lei


    Full Text Available This paper describes an automatic mosaicking algorithm for creating large-scale mosaic maps of forest height. In contrast to existing mosaicking approaches through using SAR backscatter power and/or InSAR phase, this paper utilizes the forest height estimates that are inverted from spaceborne repeat-pass cross-pol InSAR correlation magnitude. By using repeat-pass InSAR correlation measurements that are dominated by temporal decorrelation, it has been shown that a simplified inversion approach can be utilized to create a height-sensitive measure over the whole interferometric scene, where two scene-wide fitting parameters are able to characterize the mean behavior of the random motion and dielectric changes of the volume scatterers within the scene. In order to combine these single-scene results into a mosaic, a matrix formulation is used with nonlinear least squares and observations in adjacent-scene overlap areas to create a self-consistent estimate of forest height over the larger region. This automated mosaicking method has the benefit of suppressing the global fitting error and, thus, mitigating the “wallpapering” problem in the manual mosaicking process. The algorithm is validated over the U.S. state of Maine by using InSAR correlation magnitude data from ALOS/PALSAR and comparing the inverted forest height with Laser Vegetation Imaging Sensor (LVIS height and National Biomass and Carbon Dataset (NBCD basal area weighted (BAW height. This paper serves as a companion work to previously demonstrated results, the combination of which is meant to be an observational prototype for NASA’s DESDynI-R (now called NISAR and JAXA’s ALOS-2 satellite missions.

  3. Magma Pathways and Their Interactions Inferred from InSAR and Stress Modeling at Nyamulagira Volcano, D.R. Congo

    Directory of Open Access Journals (Sweden)

    Christelle Wauthier


    Full Text Available A summit and upper flank eruption occurred at Nyamulagira volcano, Democratic Republic of Congo, from 2–27 January 2010. Eruptions at Nyamulagira during 1996–2010 occurred from eruptive fissures on the upper flanks or within the summit caldera and were distributed along the ~N155E rift zone, whereas the 2011–2012 eruption occurred ~12 km ENE of the summit. 3D numerical modeling of Interferometric Synthetic Aperture Radar (InSAR geodetic measurements of the co-eruptive deformation in 2010 reveals that magma stored in a shallow (~3.5 km below the summit reservoir intruded as two subvertical dikes beneath the summit and southeastern flank of the volcano. The northern dike is connected to an ~N45E-trending intra-caldera eruptive fissure, extending to an ~2.5 km maximum depth. The southern dike is connected to an ~N175E-trending flank fissure extending to the depth of the inferred reservoir at ~3.5 km. The inferred reservoir location is coincident with the reservoir that was active during previous eruptions in 1938–1940 and 2006. The volumetric ratio of total emitted magma (intruded in dikes + erupted to the contraction of the reservoir (rv is 9.3, consistent with pressure recovery by gas exsolution in the small, shallow modeled magma reservoir. We derive a modified analytical expression for rv, accounting for changes in reservoir volume induced by gas exsolution, as well as eruptive volume. By using the precise magma composition, we estimate a magma compressibility of 1.9–3.2 × 109 Pa−1 and rv of 6.5–10.1. From a normal-stress change analysis, we infer that intrusions in 2010 could have encouraged the ascent of magma from a deeper reservoir along an ~N45E orientation, corresponding to the strike of the rift transfer zone structures and possibly resulting in the 2011–2012 intrusion. The intrusion of magma to greater distances from the summit may be enhanced along the N45E orientation, as it is more favorable to the regional rift

  4. Integrated satellite InSAR and slope stability modeling to support hazard assessment at the Safuna Alta glacial lake, Peru (United States)

    Cochachin, Alejo; Frey, Holger; Huggel, Christian; Strozzi, Tazio; Büechi, Emanuel; Cui, Fanpeng; Flores, Andrés; Saito, Carlos


    The Safuna glacial lakes (77˚ 37' W, 08˚ 50' S) are located in the headwater of the Tayapampa catchment, in the northernmost part of the Cordillera Blanca, Peru. The upper lake, Laguna Safuna Alta at 4354 m asl has formed in the 1960s behind a terminal moraine of the retreating Pucajirca Glacier, named after the peak south of the lakes. Safuna Alta currently has a volume of 15 x 106 m3. In 2002 a rock fall of several million m3 from the proximal left lateral moraine hit the Safuna Alta lake and triggered an impact wave which overtopped the moraine dam and passed into the lower lake, Laguna Safuna Baja, which absorbed most of the outburst flood from the upper lake, but nevertheless causing loss in cattle, degradation of agricultural land downstream and damages to a hydroelectric power station in Quitaracsa gorge. Event reconstructions showed that the impact wave in the Safuna Alta lake had a runup height of 100 m or more, and weakened the moraine dam of Safuna Alta. This fact, in combination with the large lake volumes and the continued possibility for landslides from the left proximal moraine pose a considerable risk for the downstream settlements as well as the recently completed Quitaracsa hydroelectric power plant. In the framework of a project funded by the European Space Agency (ESA), the hazard situation at the Safuna Alta lake is assessed by a combination of satellite radar data analysis, field investigations, and slope stability modeling. Interferometric analyses of the Synthetic Aperture Radar (InSAR) of ALOS-1 Palsar-1, ALOS-2 Palsar-2 and Sentinel-1 data from 2016 reveal terrain displacements of 2 cm y-1 in the detachment zone of the 2002 rock avalanche. More detailed insights into the characteristics of these terrain deformations are gained by repeat surveys with differential GPS (DGPS) and tachymetric measurements. A drone flight provides the information for the generation of a high-resolution digital elevation model (DEM), which is used for the

  5. 干涉合成孔径雷达及其在火山研究中的应用(第一部分:InSAR原理)%Interferometric synthetic aperture radar (InSAR) and its applications to study volcanoes(part 1: Principles of InSAR)

    Institute of Scientific and Technical Information of China (English)

    路中; 张继贤


    Interferometric synthetic aperture radar (InSAR) is a remote sensing technique capable of measuring ground surface deformation with sub-centimeter precision and spatial resolution in tens-of-meters over a large region. This paper reviews the basics of InSAR technique, illustrates how InSAR works, and discusses issues related to InSAR deformation mapping.%干涉合成孔径雷达是一项能够对地表变形进行测量的遥感技术,在一个巨大区域内,它的变形测量精度可达亚厘米级,而其空间分辨率则在数十米以内.本文回顾了InSAR技术的基本理论,阐明了它的工作原理,并对应用InSAR技术进行地表变形测量的相关问题进行了讨论.

  6. Multi-temporal InSAR monitoring of landslides in a tropical urban environment: focus on Bukavu (DR Congo) (United States)

    Nobile, Adriano; Monsieurs, Elise; Dewitte, Olivier; d'Oreyes, Nicolas; Kervyn, Francois


    The western branch of the East African Rift System, in Central Africa, is characterized by the presence of several geohazards: earthquakes, volcanoes, and landslides. Every year, landslides cause fatalities, structural and functional damage to infrastructure and private properties with serious disruptions of the organization of societies and severe impact on the populations. These impacts are particularly important in the city of Bukavu (DR Congo) located within the Rift, on the southern shore of Lake Kivu. Large slow-moving landslides continuously affect highly populated slopes in the city. However little is known about their actual kinematics and the processes at play. Here we use multi-temporal InSAR technique to monitor these ground deformations. Using 50 Cosmo-SkyMed SAR images, acquired between March - October 2015 with a revisiting time of 8 days (ascending and descending orbits), we produce displacement-rate maps and ground deformation time series using the PS technique. Movements with a velocity >5cm/yr are detected, which is consistent with field observations. DGPS measurements, taken at 21 benchmarks in the area during the same period, allow validating the results. Similar ground deformation rates are found for the period 2002-2008 using Envisat ASAR images. Furthermore, comparison with rainfall monitoring data acquire on site should help us to understand the influence of water and the tropical seasonality in the slide mechanisms.

  7. An Improved InSAR Image Co-Registration Method for Pairs with Relatively Big Distortions or Large Incoherent Areas

    Directory of Open Access Journals (Sweden)

    Zhenwei Chen


    Full Text Available Co-registration is one of the most important steps in interferometric synthetic aperture radar (InSAR data processing. The standard offset-measurement method based on cross-correlating uniformly distributed patches takes no account of specific geometric transformation between images or characteristics of ground scatterers. Hence, it is inefficient and difficult to obtain satisfying co-registration results for image pairs with relatively big distortion or large incoherent areas. Given this, an improved co-registration strategy is proposed in this paper which takes both the geometric features and image content into consideration. Firstly, some geometric transformations including scale, flip, rotation, and shear between images were eliminated based on the geometrical information, and the initial co-registration polynomial was obtained. Then the registration points were automatically detected by integrating the signal-to-clutter-ratio (SCR thresholds and the amplitude information, and a further co-registration process was performed to refine the polynomial. Several comparison experiments were carried out using 2 TerraSAR-X data from the Hong Kong airport and 21 PALSAR data from the Donghai Bridge. Experiment results demonstrate that the proposed method brings accuracy and efficiency improvements for co-registration and processing abilities in the cases of big distortion between images or large incoherent areas in the images. For most co-registrations, the proposed method can enhance the reliability and applicability of co-registration and thus promote the automation to a higher level.

  8. Constraints on geothermal reservoir volume change calculations from InSAR surface displacements and injection and production data (United States)

    Kaven, J. Ole; Barbour, Andrew J.; Ali, Tabrez


    Continual production of geothermal energy at times leads to significant surface displacement that can be observed in high spatial resolution using InSAR imagery. The surface displacement can be analyzed to resolve volume change within the reservoir revealing the often-complicated patterns of reservoir deformation. Simple point source models of reservoir deformation in a homogeneous elastic or poro-elastic medium can be superimposed to provide spatially varying, kinematic representations of reservoir deformation. In many cases, injection and production data are known in insufficient detail; but, when these are available, the same Green functions can be used to constrain the reservoir deformation. Here we outline how the injection and production data can be used to constrain bounds on the solution by posing the inversion as a quadratic programming with inequality constraints and regularization rather than a conventional least squares solution with regularization. We apply this method to InSAR-derived surface displacements at the Coso and Salton Sea Geothermal Fields in California, using publically available injection and production data. At both geothermal fields the available surface deformation in conjunction with the injection and production data permit robust solutions for the spatially varying reservoir deformation. The reservoir deformation pattern resulting from the constrained quadratic programming solution is more heterogeneous when compared to a conventional least squares solution. The increased heterogeneity is consistent with the known structural controls on heat and fluid transport in each geothermal reservoir.

  9. An Improved InSAR Image Co-Registration Method for Pairs with Relatively Big Distortions or Large Incoherent Areas. (United States)

    Chen, Zhenwei; Zhang, Lei; Zhang, Guo


    Co-registration is one of the most important steps in interferometric synthetic aperture radar (InSAR) data processing. The standard offset-measurement method based on cross-correlating uniformly distributed patches takes no account of specific geometric transformation between images or characteristics of ground scatterers. Hence, it is inefficient and difficult to obtain satisfying co-registration results for image pairs with relatively big distortion or large incoherent areas. Given this, an improved co-registration strategy is proposed in this paper which takes both the geometric features and image content into consideration. Firstly, some geometric transformations including scale, flip, rotation, and shear between images were eliminated based on the geometrical information, and the initial co-registration polynomial was obtained. Then the registration points were automatically detected by integrating the signal-to-clutter-ratio (SCR) thresholds and the amplitude information, and a further co-registration process was performed to refine the polynomial. Several comparison experiments were carried out using 2 TerraSAR-X data from the Hong Kong airport and 21 PALSAR data from the Donghai Bridge. Experiment results demonstrate that the proposed method brings accuracy and efficiency improvements for co-registration and processing abilities in the cases of big distortion between images or large incoherent areas in the images. For most co-registrations, the proposed method can enhance the reliability and applicability of co-registration and thus promote the automation to a higher level.

  10. Magnitude and extent of land subsidence in central Mexico revealed by regional InSAR ALOS time-series survey (United States)

    Chaussard, E.; Wdowinski, S.; Amelung, F.; Cabral-Cano, E.


    Massive groundwater extraction is very common in Mexico and is well known to result in land subsidence. However, most surveys dedicated to land subsidence focus on one single city, mainly Mexico City, and thus fail to provide a comprehensive picture of the problem. Here we use a space-based radar remote sensing technique, known as Interferometric Synthetic Aperture Radar (InSAR) to detect land subsidence in the entire central Mexico area. We used data from the Japanese satellite ALOS, processed over 600 SAR images acquired between 2007-2011 and produced over 3000 interferograms to cover and area of 200,000 km2 in central Mexico. We identify land subsidence in twenty-one areas, including seventeen cities, namely from east to west, Puebla, Mexico city, Toluca de Lerdo, Queretaro, San Luis de la Paz, south of San Luis de la Paz, Celaya, south of Villa de Reyes, San Luis Potosi, west of Villa de Arista, Morelia, Salamanca, Irapuato, Silao, Leon, Aguascalientes, north of Aguascalientes, Zamora de Hidalgo, Guadalajara, Ahuacatlan, and Tepic. Subsidence rates of 30 cm/yr are observed in Mexico City, while in the other locations typical rates of 5-10 cm/yr are noticed. Regional surveys of this type are necessary for the development of hazard mitigation plans and efficient use of ground-based monitoring. We additionally correlate subsidence with land use, surface geology, and faults distribution and suggest that groundwater extraction for agricultural, urban, and industrial uses are the main causes of land subsidence. We also reveal that the limits of the subsiding areas often correlate with existing faults, motion on these faults being driven by water extraction rather than by tectonic activity. In all the subsiding locations we observe high ground velocity gradients emphasizing the significant risks associated with land subsidence in central Mexico. Averaged 2007-2011 ground velocity map from ALOS InSAR time-series in central Mexico, revealing land subsidence in 21

  11. InSAR Application in the Land Subsidence Monitoring of Laiguangying Area,Beijing City%INSAR技术在北京来广营地区地面沉降监测中的应用

    Institute of Scientific and Technical Information of China (English)



    With the rapid development of Beijing urban construction,more and more the land subsidence in the plain area becomes severe.Interferometric Synthetic Aperture Radar(InSAR) has much more advantages with macro-region,quick-speed,high-precision and short-periodicity,and it can provide convenient and efficient technical methods for monitoring the land subsidence.This paper uses SAR data from ENVISAT-1 satellite to monitor the land subsidence of Laiguangying area of Beijing from 2004 to 2005,and get the monitoring results through InSAR technology.The analysis results show that it is feasible to monitor land subsidence in Beijing plain area with InSAR technology.%北京市平原地区地面沉降危害日益显著,合成孔径雷达干涉测量(InSAR)具有快速、高精度、周期短等优势,可为城市地面沉降监测提供有效的技术手段。本文选用ENVISAT-1卫星SAR数据监测研究2004-2005年北京来广营地区地面沉降,利用InSAR差分技术得到该地区地面沉降监测结果。

  12. Using InSAR to investigate long term caldera unrest: case studies from Yellowstone and Long Valley (United States)

    battaglia, maurizio


    Interpreting geodetic measurements can be particularly difficult in the case of slow, years-to-decades deformation, such as that commonly observed at large Quaternary silicic calderas. For example, Yellowstone caldera has shown a complex behavior over recent decades: uplift of resurgent domes within the caldera started sometime after 1923, reaching a total of 90 cm, but in 1984 the deformation reversed to subsidence at a rate of 1-2 cm/yr until 1992. Starting in 1992, the deformation began migrating from one resurgent dome to the other, and deformation was also detected along the caldera boundary - the so-called Northern Caldera Rim - starting in the mid-1990s. Evidence from geodetic surveys suggests that magma intrusion and/or pressurization of hydrothermal fluids may both drive uplift at Yellowstone. Geodetic measurements at Long Valley caldera have also revealed multiple episodes of caldera uplift, but in contrast to Yellowstone, deformation is largely restricted to the caldera's single resurgent dome. The fact that the energy released during the resurgent dome uplift is much larger than that which can be explained by seismic activity within and around the caldera, together with the observation that the onset of accelerated deformation precedes increases in earthquake activity by several weeks, suggests that the major source of caldera unrest is probably magma intrusion beneath the resurgent dome. Here we present time series of surface deformation for Yellowstone and Long Valley retrieved by applying the SBAS InSAR technique. We estimate the average regional deformation signal by using the mean velocity values derived from coherent SAR pixels belonging to areas outside the caldera. This tectonic signal is removed from the InSAR displacement and we modeled the InSAR, leveling, and gravity measurements to retrieve the best fitting source parameters. For Yellowstone caldera, different distinct sources, either hydrothermal or magmatic, have been intermittently

  13. Development and testing of an automated High-resolution InSAR volcano-monitoring system in the MED-SUV project (United States)

    Chowdhury, Tanvir Ahmed; Minet, Christian; Fritz, Thomas; Rodriguez Gonzalez, Fernando


    Volcanic unrest which produces a variety of geological and hydrological hazards is difficult to predict. Therefore it is important to monitor volcanoes continuously. The monitoring of active volcanoes requires the reliable measurement of surface deformation before, during and after volcanic activities. Besides the improvements of the understanding of geophysical processes underlying the volcanic systems of Vesuvius/ Campi Flegrei and Mt. Etna, one of the main goals of the MED-SUV (MEDiterranean SUpersite Volcanoes) project is to design a system for automatically monitoring ground deformations over active volcanoes. Space-borne synthetic aperture radar (SAR) interferometry (InSAR), persistent scatterer interferometry (PSI) and small baseline subset algorithm (SBAS) provide powerful tools for observing the surface changes with millimeter accuracy. All the mentioned techniques address the challenges by exploiting medium to large SAR image stacks. The generation of interferometric products constitutes a major effort in terms of processing and planning. It requires a high degree of automation, robustness and quality control of the overall process. As a consequence of these requirements and constrains, the Integrated Wide Area Processor (IWAP) developed at DLR is introduced in the framework of a remote sensing task of MED-SUV project. The IWAP has been conceived and designed to optimize the processing workflow in order to minimize the processing time. Moreover, a quality control concept has been developed and integrated in the workflow. The IWAP is structured into three parts: (i) firstly, preparation of an order file containing some configuration parameters and invokes the processor; (ii) secondly, upon request from the processor, the operator performs some manual interactions by means of visual interfaces; (iii) analysis of the final product supported by extensive product visualization. This visualization supports the interpretation of the results without the need of

  14. Identifying Active Faults by Improving Earthquake Locations with InSAR Data and Bayesian Estimation: The 2004 Tabuk (Saudi Arabia) Earthquake Sequence

    KAUST Repository

    Xu, Wenbin


    A sequence of shallow earthquakes of magnitudes ≤5.1 took place in 2004 on the eastern flank of the Red Sea rift, near the city of Tabuk in northwestern Saudi Arabia. The earthquakes could not be well located due to the sparse distribution of seismic stations in the region, making it difficult to associate the activity with one of the many mapped faults in the area and thus to improve the assessment of seismic hazard in the region. We used Interferometric Synthetic Aperture Radar (InSAR) data from the European Space Agency’s Envisat and ERS‐2 satellites to improve the location and source parameters of the largest event of the sequence (Mw 5.1), which occurred on 22 June 2004. The mainshock caused a small but distinct ∼2.7  cm displacement signal in the InSAR data, which reveals where the earthquake took place and shows that seismic reports mislocated it by 3–16 km. With Bayesian estimation, we modeled the InSAR data using a finite‐fault model in a homogeneous elastic half‐space and found the mainshock activated a normal fault, roughly 70 km southeast of the city of Tabuk. The southwest‐dipping fault has a strike that is roughly parallel to the Red Sea rift, and we estimate the centroid depth of the earthquake to be ∼3.2  km. Projection of the fault model uncertainties to the surface indicates that one of the west‐dipping normal faults located in the area and oriented parallel to the Red Sea is a likely source for the mainshock. The results demonstrate how InSAR can be used to improve locations of moderate‐size earthquakes and thus to identify currently active faults.

  15. Using InSAR Coherence to Map Stand Age in a Boreal Forest

    Directory of Open Access Journals (Sweden)

    Naiara Pinto


    Full Text Available The interferometric coherence parameter γ estimates the degree of correlation between two Synthetic Aperture Radar (SAR images and can be influenced by vegetation structure. Here, we investigate the use of repeat-pass interferometric coherence γ to map stand age, an important parameter for the study of carbon stocks and forest regeneration. In August 2009 NASA’s L-band airborne sensor UAVSAR (Uninhabited Aerial Vehicle Synthetic Aperture Radar acquired zero-baseline data over Quebec with temporal separation ranging between 45 min and 9 days. Our analysis focuses on a 66 km2 managed boreal forest and addresses three questions: (i Can coherence from L-band systems be used to model forest age? (ii Are models sensitive to weather events and temporal baseline? and (iii How is model accuracy impacted by the spatial scale of analysis? Linear regression models with 2-day baseline showed the best results and indicated an inverse relationship between γ and stand age. Model accuracy improved at 5 ha scale (R2 = 0.75, RMSE = 5.3 as compared to 1 ha (R2 = 0.67, RMSE = 5.8. Our results indicate that coherence measurements from L-band repeat-pass systems can estimate forest age accurately and with no saturation. However, empirical model relationships and their accuracy are sensitive to weather events, temporal baseline, and spatial scale of analysis.

  16. The postseismic response to the 2002 M 7.9 Denali Fault earthquake: Constraints from InSAR 2003-2005 (United States)

    Biggs, J.; Burgmann, R.; Freymueller, J.T.; Lu, Zhiming; Parsons, B.; Ryder, I.; Schmalzle, G.; Wright, Tim


    InSAR is particularly sensitive to vertical displacements, which can be important in distinguishing between mechanisms responsible for the postseismic response to large earthquakes (afterslip, viscoelastic relaxation). We produce maps of the surface displacements resulting from the postseismic response to the 2002 Denali Fault earthquake, using data from the Canadian Radarsat-1 satellite from the periods summer 2003, summer 2004 and summer 2005. A peak-to-trough signal of amplitude 4 cm in the satellite line of sight was observed between summer 2003 and summer 2004. By the period between summer 2004 and summer 2005, the displacement rate had dropped below the threshold required for observation with InSAR over a single year. The InSAR observations show that the principal postseismic relaxation process acted at a depth of ???50 km, equivalent to the top of the mantle. However, the observations are still incapable of distinguishing between distributed (viscoelastic relaxation) and localized (afterslip) deformation. The imposed coseismic stresses are highest in the lower crust and, assuming a Maxwell rheology, a viscosity ratio of at least 5 between lower crust and upper mantle is required to explain the contrast in behaviour. The lowest misfits are produced by mixed models of viscoelastic relaxation in the mantle and shallow afterslip in the upper crust. Profiles perpendicular to the fault show significant asymmetry, which is consistent with differences in rheological structure across the fault. ?? 2008 The Author Journal compilation ?? 2008 RAS.

  17. Monitoring of Landslide Activity by Synergic Use of X-Band and L-Band InSAR in the Ceske Stredohori Mts., Czech Republic (United States)

    Kadlecik, Pavel; Lazecky, Milan; Nico, Giovanni; Mascholo, Luigi; Balek, Jan; Marek, Tomas


    Neovolcanic range of the České Středohoří Mts. in northwestern Czech Republic represents the region with susceptibility to various types of landslides. Evaluation of landslide activity using InSAR can reveal valuable information both in spatial and temporal scale. On the other hand, we cannot obtain full spatial information in hilly terrain of České Středohoří Mts., another limit is the presence of dense vegetation.Two approaches are applied in our research. Firstly, we would like to delimit an area of few hundreds of square kilometers and to process as much as possible of SAR images using multitemporal InSAR techniques (PSI, Quasi-PS, SBAS) to acquire of spatiotemporal distribution of possible active landslides. Secondly, for selected localities we want to process only SAR images with suitable dates of their origin (following the dates of known landslide activity, dates of in-situ monitoring etc.) using X-band, C-band and L-band SAR data.

  18. A Quadtree In SAR Data Reduction Method Based on Covariance Function%顾及协方差函数的自适应四叉树 InSAR 数据压缩算法

    Institute of Scientific and Technical Information of China (English)

    张静; 张勤; 赵超英; 张菊清


    利用 I nSAR 变形监测结果进行形变机理反演时,由于 I nSAR 获取的数据点众多,且往往含有较多的误差乃至粗差点,严重制约了反演计算的效率和可靠性。为此,本文提出顾及 I nSAR 变形监测数据的物理空间相关性来设立协方差函数,并依据协方差函数确定四叉树象限分解阈值和最大象限大小的自适应四叉树分解 I nSAR 数据压缩算法。本算法能够在尽可能保留形变信号特征细节信息的同时,极大地降低 I nSAR 数据量。论文以西安地区地面沉降 I nSAR 形变监测结果为例进行了试验分析,验证了该算法的有效性。结果表明,该方法能够在不损失形变信号特征的同时,有效地实现 I nSAR 数据压缩和噪声消除的目的。%A major problem in inversion of deformation mechanism using InSAR data is that the InSAR results often contain thousands to millions of data points.Furthermore,there always exist errors and even some blunders,which make the data inversion be lower efficient and lower reliable.Thus,an adaptive quadtree decomposition method for InSAR data reduction is proposed in order to reduce the data numbers without losing the significant information about the deformation.The two important parameters of quadtree decomposition by covariance function are determined,which are eatabl ished by taking account of the physical spatial correlation of InSAR data.The algorithm can preserve details of deformation as much as possible and achieve efficient data reduction.This method is evaluated with InSAR data over Xi’an land subsidence.The results indicate that the algorithm proposed in this manuscript can not only reduce InSAR data number efficiently under a very good preservation of deformation signal,but canel iminate the noise of deformation results efficiently.

  19. The coseismic slip of the 2011 Tarlay earthquake in eastern Myanmar: constraints from InSAR and field investigations (United States)

    Wang, Y.; Lin, Y. N.; Tun, S.; Khaing, S.; Simons, M.; Sieh, K. E.


    Field investigations and InSAR analyses confirm the Mw 6.8 March 24, 2011 Tarlay earthquake occurred on the westernmost segment of the Nam Ma fault. This 30-km-long segment is structurally separated from the main trace of the Nam Ma fault by a dilatational stepover. Field measurements show a 1.25-m peak surface offset in the central part of the fault which gradually decreases toward the northeast. The coseismic slip distribution inverted from InSAR and pixel tracking results yields a narrow and shallow slip patch. Most of the slip occurred at the depth between 3 and 9 km on the sub-vertical fault, with the peak slip of ~4 m at the depth of 3-6 km. The Nam Ma fault transects through the cold Paleozoic continental crust and is away from any region of anomalously high geothermal gradient. Thus we believe that rather than the result of a shallow brittle-ductile transition depth, this narrow rupture patch may reflect either the past slip history or the state of stress before the 2011 earthquake. A similar example may be the earthquake sequence on the Rokko-Nojima fault system in Japan, where a shallow patch that ruptured on the Rokko fault in 1596 occurred above (at shallower depths) of the fault slip during the 1995 Kobe earthquake. This analog suggests that a deeper event may have happened prior to the 2011 Tarlay earthquake or may happen in the future. With an average slip rate of 0.6-2.4 mm/yr from late-Miocene to present [Lacassin et al., 1998], we estimate the recurrence interval for moderate events like the Mw 6.8 Tarlay earthquake to be 230 to 930 years at the Nam Ma fault. If the entire 215-km long Nam Ma fault ruptures all at once, it could generate an earthquake of Mw 7.7 with an average recurrence interval of 2200 to 9000 years.

  20. GPS and Satellite InSAR Observations of Landslide Activity at the Sinking Canyon in South Central Idaho (United States)

    Aly, M. H.; Glenn, N. F.; Thackray, G. D.


    Multiple rotational, transitional, and lateral spread landslides have occurred in south central Idaho where basalt lava flows overly unconsolidated lake and fluvial sediments at the Sinking Canyon. The canyon is about 0.1 km deep and 0.25-1 km wide along a 4-km segment of the Salmon Falls Creek (SFC). Local topography and hydrological conditions are most likely the major triggering factors that have initiated landslides by increasing the gravitational stresses and weakening the canyon wall materials. Landslide activity has created natural dams of SFC, which in turn has resulted in forming large lakes with a potential flooding hazard to life and property downstream. In this study, we use campaign Global Positioning System (GPS) measurements of 2003-2004 and Synthetic Aperture Radar Interferometric (InSAR) data acquired during 1992-2007 by the European radar satellites (ERS-1 and ERS-2) to identify, monitor, and analyze recent landslide activity at SFC. Results show that three main landslides have been active during the period of observation: the Salmon Falls landslide (SFL) that has been first reported in 1999, the historical 1937 landslide, and a third unnamed landslide to the north of the 1937 slide. InSAR measurements indicate that the SFL has been active during the period of our earliest interferogram (1992-1993) whereas the slide head has detached and has moved away from the eastern canyon wall about 3 cm. Over the years, the SFL body and toe have been pushed westward repetitively at rates of about 3-7 cm/yr. The toe is confined by the western canyon wall and thus is pushed upward in some years causing slight uplift (2-3 cm). Our field observations reveal many transverse and radial cracks associated with the deformation pattern caused by recurring motions. The historic 1937 slide is the largest mass wasting and is the least active landslide in the study area. The unnamed slide shows episodic activity with varying rates (0-4 cm/yr) of line-of-sight motions. This

  1. Current deformation in Central Afar and triple junction kinematics deduced from GPS and InSAR measurements (United States)

    Doubre, Cécile; Déprez, Aline; Masson, Frédéric; Socquet, Anne; Lewi, Elias; Grandin, Raphaël; Nercessian, Alexandre; Ulrich, Patrice; De Chabalier, Jean-Bernard; Saad, Ibrahim; Abayazid, Ahmadine; Peltzer, Gilles; Delorme, Arthur; Calais, Eric; Wright, Tim


    Kinematics of divergent boundaries and Rift-Rift-Rift junctions are classically studied using long-term geodetic observations. Since significant magma-related displacements are expected, short-term deformation provides important constraints on the crustal mechanisms involved both in active rifting and in transfer of extensional deformation between spreading axes. Using InSAR and GPS data, we analyse the surface deformation in the whole Central Afar region in detail, focusing on both the extensional deformation across the Quaternary magmato-tectonic rift segments, and on the zones of deformation transfer between active segments and spreading axes. The largest deformation occurs across the two recently activated Asal-Ghoubbet (AG) and Manda Hararo-Dabbahu (MH-D) magmato-tectonic segments with very high strain rates, whereas the other Quaternary active segments do not concentrate any large strain, suggesting that these rifts are either sealed during interdyking periods or not mature enough to remain a plate boundary. Outside of these segments, the GPS horizontal velocity field shows a regular gradient following a clockwise rotation of the displacements from the Southeast to the East of Afar, with respect to Nubia. Very few shallow creeping structures can be identified as well in the InSAR data. However, using these data together with the strain rate tensor and the rotations rates deduced from GPS baselines, the present-day strain field over Central Afar is consistent with the main tectonic structures, and therefore with the long-term deformation. We investigate the current kinematics of the triple junction included in our GPS data set by building simple block models. The deformation in Central Afar can be described by adding a central microblock evolving separately from the three surrounding plates. In this model, the northern block boundary corresponds to a deep EW-trending trans-tensional dislocation, locked from the surface to 10-13 km and joining at depth the

  2. Geological and InSAR surveys highlight tectonic hazard in densely inhabited areas on the lower southeastern flank of Mount Etna volcano, Italy (United States)

    Neri, Marco; Sansosti, Eugenio; Casu, Francesco; Leonardi, Anna; Pepe, Antonio; Pepe, Susi; Solaro, Giuseppe


    A constant seaward sliding mechanism is affecting the eastern to southern flanks of Mt. Etna volcano, involving an overall on-shore area of >700 km2.The margins of this unstable area are marked by the Pernicana Fault System to the north and the Ragalna Fault System to the south-west. The unstable area is divided into several blocks characterized by different kinematics and delimited by active faults crossing, in several cases, urban areas, towns and villages. One of these structural discontinuities is the Trecastagni-S.G.La Punta-Aci Trezza fault system, a tectonic structure extending from the volcano summit (where it trends NNW-SSE), to the lower southeastern flank (trending NW-SE) and reaching the coast at the Aci Trezza village (WNW-ESE and E-W). The last segment of this tectonic system crosses several important roads and man-made structures within Aci Trezza, and continues for a few kilometers off-shore crossing the Faraglioni stacks-Lachea island. Recently, analysis of long-period InSAR data has added some details to the sliding motion on the lower south-eastern flank of the volcano, particularly on the S.G.La Punta-Aci Trezza fault segments. Field geological and instrumental data confirmed the slip activity and the extension of the tectonically disturbed areas, highlighting a transition zone between the two main fault segments. On the other hand, some of the features detected by InSAR are not clearly visible in the field and were never detected before by classical geological surveys. These results are of crucial importance in terms of hazard related to tectonic movements, especially in densely inhabited zones such as the south-eastern flank of Etna, where more than half a million people live. The structural details obtained through these kinds of studies may guide future land use planning appropriately also within towns and villages, where aseismic and seismogenic very active faults are evident at the surfaces.

  3. Detecting and Measuring Land Subsidence in Houston-Galveston, Texas using Interferometric Synthetic Aperture Radar (InSAR) and Global Positioning System Data, 2012-2016 (United States)

    Reed, A.; Baker, S.


    Several cities in the Houston-Galveston (HG) region in Texas have subsided up to 13 feet over several decades due to natural and anthropogenic processes [Yu et al. 2014]. Land subsidence, a gradual sinking of the Earth's surface, is an often human-induced hazard and a major environmental problem expedited by activities such as mining, oil and gas extraction, urbanization and excessive groundwater pumping. We are able to detect and measure subsidence in HG using interferometric synthetic aperture radar (InSAR) and global positioning systems (GPS). Qu et al. [2015] used ERS, Envisat, and ALOS-1 to characterize subsidence in HG from 1995 to 2011, but a five-year gap in InSAR measurements exists due to a lack of freely available SAR data. We build upon the previous study by comparing subsidence patterns detected by Sentinel-1 data starting in July 2015. We used GMT5SAR to generate a stack of interferograms with perpendicular baselines less than 100 meters and temporal baselines less than 100 days to minimize temporal and spatial decorrelation. We applied the short baseline subset (SBAS) time series processing using GIAnT and compared our results with GPS measurements. The implications of this work will strengthen land subsidence monitoring systems in HG and broadly aid in the development of effective water resource management policies and strategies.

  4. Three-dimensional deformation mapping of a dike intrusion event in Sakurajima in 2015 by exploiting the right- and left-looking ALOS-2 InSAR (United States)

    Morishita, Yu; Kobayashi, Tomokazu; Yarai, Hiroshi


    One of the limitations of the interferometric synthetic aperture radar (InSAR) is its one-dimensional measurement capability. Although three-dimensional (3-D) deformation can be studied if there are three or more measurements with different viewing geometries, it has not been executed because almost all SAR data are acquired using a right-looking geometry. For the Sakurajima volcanic activity on 15 August 2015, ALOS-2 conducted SAR observations from four different viewing directions, ascending/descending and right-/left-looking, enabling the retrieval of 3-D deformation data only from the InSAR results. We have retrieved 3-D deformation with high precision and resolution by a weighted least squares approach. Expansive deformation of over 10 cm has been observed with standard errors of 0.8, 3.4, and 0.7 cm for east-west, north-south, and up-down components, respectively. It is inferred that a dike of 1.7 × 106m3 volume intruded beneath the Showa crater at a depth of 0.4-1.2 km.

  5. 4D map of the Kilauea summit shallow magmatic system constrained by InSAR time series and geometry-free inversions (United States)

    Zhai, G.; Shirzaei, M.


    The Kilauea volcano, Hawaii Island, is one of the most active volcanoes worldwide. Its complex system, including magma reservoirs and rift zones, provides a unique opportunity to investigate the dynamics of magma transport and supply. The models explaining the system are yet limited to the first order analytical solutions with fixed geometry. To obtain a 4D map of the volume changes at the Kilauea summit magmatic system (KSMS), we implement a novel geometry-free time-dependent inverse modeling scheme, using a distribution of point center of dilatations (PCDs). The model is constrained using high resolution surface deformation data, which are obtained through InSAR time series analysis of well populated SAR data sets acquired at two overlapping tracks of Envisat satellite during 2003 and 2011. Principal Component Analysis (PCA) of the 4D maps of volume change identifies five major active reservoir beneath Kilauea caldera. The southern caldera reservoir (SCR) gains volume slowly till 2006 before its rapid inflation during 2006 - mid-2007, followed by deflation until the start of re-inflation in mid-2010. Other reservoirs show episodic temporal correlation and anti-correlation with SCR. We found that the top-down relation between reservoirs at the Kilauea summit is not necessarily valid at all time scales. Identifying statistically significant PCDs through Chi-square test, we develop and apply a boundary element modeling scheme to solve for the volume change time series and complex geometry of the summit magmatic system. Availability of such models allows realistic estimates of volume change and associated seismic hazard and enhance the forecast models.

  6. Study on crustal deformation of the Ms6. 6 Damxung earthquake in 2008 by InSAR measurements

    Directory of Open Access Journals (Sweden)

    Xuejun Qiao


    Full Text Available Three Envisat images from ESA were used to derive the pre – and co-seismic deformation interfereograms caused by the Damxung Ms6. 6 earthquake of Oct. 6, 2008, by using InSAR. The result shows no significant crustal motion more than 4 months before the earthquake, but a maximum co-seismic displacement of about 0.3 m in an epicentral area of 20 km × 20 km. The deformation field was symmetrically distributed about a NS axis, where the west side subsided and the east side uplifted. We used a linear elastic dislocation model in half space and a nonlinear constraint optimized algorithm to estimate the slip distribution along the fault. The results indicates that the epicenter is located at 90.374°E, 29.745°N with a moment magnitude of Mw6. 35. The earthquake is dominated by normal faulting with a maximum slip of 3 m on a 12 km × 11 km fault plane striking S189°W, dipping 60° to NW at a depth of 9.5 km, and is located at a sub-fault of the southeastern Piedmont of the Nyainqentanglha mountains. The relatively shallow depth of earthquake is related to relatively high heat flow in the area.

  7. Subsidence monitoring in coal area using time-series InSAR combining persistent scatterers and distributed scatterers (United States)

    Zhang, Zhengjia; Wang, Chao; Tang, Yixian; Fu, Qiaoyan; Zhang, Hong


    In coal mining areas, ground subsidence persistently happens, which produces serious environmental issues and affects the development of cities. To monitor the ground deformation due to coal mining, a modified time-series InSAR technique combining persistent scatterers (PSs) and distributed scatterers (DSs) is presented in this paper. In particular, DSs are efficiently identified using classified information and statistical characteristics. Furthermore, a two-scale network is introduced into traditional PSI to deal with PSs and DSs in a multi-layer framework by taking the advantage of the robust of PSs and the widely distribution of DSs. The proposed method is performed to investigate the subsidence of Huainan City, Anhui province (China), during 2012-2013 using 14 scenes of Radarsat-2 images. Experimental results show that the proposed method can ease the estimation complexity and significantly increase the spatial density of measurement points, which can provide more detailed deformation information. Result shows that there are obvious subsidence areas detected in the test site with subsidence velocity larger than 5 cm/year. The proposed method brings practical applications for non-urban area deformation monitoring.

  8. The Crustal Deformation Revealed by GPS and InSAR in the Northwest Corner of the Tarim Basin, Northwestern China (United States)

    Qiao, Xuejun; Yu, Pengfei; Nie, Zhaosheng; Li, Jie; Wang, Xiaoqiang; Kuzikov, Sergey I.; Wang, Qi; Yang, Shaomin


    The Northwestern Corner of the Tarim Basin (hereinafter the NOCTB) is surrounded by the Pamir salient, the south Tian Shan Mountains, and the Tarim Basin. The tectonic settings of these three structures dominate the crustal deformation patterns and seismic events in the NOCTB and its adjacent regions. We integrated the GPS and InSAR measurements to derive a large-scale three-dimensional velocity map of the NOCTB. The GPS data obtained during 38 campaigns between 1992 and 2013 were used to derive a horizontal velocity field. 149 Envisat ASAR images observed along four satellite tracks between 2003 and 2011 were processed to get a line of sight rate map based on the small baseline subset time series analysis method and a homogeneous isotropic model. Finally, we modeled the dip angle, slip rate, and locking depth of selected faults. The results indicate that the crustal convergence is not uniformly distributed across the NOCTB: more than 50% of the N-S shortening is absorbed by the Tian Shan Mountains in the southwest, whereas the N-S shortening rates are low and therefore the strain accommodations are smaller in the east of the NOCTB. The vertical displacement rates in the NOCTB range from -2 to 3 mm/year with different magnitudes in different areas. The main uplift areas are located on the junction region between frontal MPT and the southwestern STT including the Kazkeaerte fault, Aikenerte fault, the Southern Artux fault, and part areas in north of the Kalping fault. The main subsident areas are located on central belt of STT including the Totgumbaz-Alpaleh fault, Nothern Artux fault, the southwestern Karatieke fault, and the north of Puchang/Piqiang fault. Compared with the substantial N-S shortening rate of 10 mm/year, the vertical rate across each fault ranges from approximately -1 to 1 mm/year, suggesting that vertical movement in NOCTB area is relatively moderate at present. Both the horizontal and vertical rates show obvious changes across the Kazkeaerte

  9. Estimation of Forest Height Using Spaceborne Repeat-Pass L-Band InSAR Correlation Magnitude over the US State of Maine

    Directory of Open Access Journals (Sweden)

    Yang Lei


    Full Text Available This paper describes a novel, simple and efficient approach to estimate forest height over a wide region utilizing spaceborne repeat-pass InSAR correlation magnitude data at L-band. We start from a semi-empirical modification of the RVoG model that characterizes repeat-pass InSAR correlation with large temporal baselines (e.g., 46 days for ALOS by taking account of the temporal change effect of dielectric fluctuation and random motion of scatterers. By assuming (1 the temporal change parameters and forest backscatter profile/extinction coefficient follow some mean behavior across each inteferogram; (2 there is minimal ground scattering contribution for HV-polarization; and (3 the vertical wavenumber is small, a simplified inversion approach is developed to link the observed HV-polarized InSAR correlation magnitude to forest height and validated using ALOS/PALSAR repeat-pass observations against LVIS lidar heights over the Howland Research Forest in central Maine, US (with RMSE < 4 m at a resolution of 32 hectares. The model parameters derived from this supervised regression are used as the basis for propagating the estimates of forest height to available interferometric pairs for the entire state of Maine, thus creating a state-mosaic map of forest height. The present approach described here serves as an alternative and complementary tool for other PolInSAR inversion techniques when full-polarization data may not be available. This work is also meant to be an observational prototype for NASA’s DESDynI-R (now called NISAR and JAXA’s ALOS-2 satellite missions.

  10. The 2009 L’Aquila earthquake coseismic rupture: open issues and new insights from 3D finite element inversion of GPS, InSAR and strong motion data

    Directory of Open Access Journals (Sweden)

    Manuela Volpe


    Full Text Available We present a Finite Element inverse analysis of the static deformation field for the Mw= 6.3, 2009 L’Aquila earthquake, in order to infer the rupture slip distribution on the fault plane. An univocal solution for the rupture slip distribution has not been reached yet with negative impact for reliable hazard scenarios in a densely populated area. In this study, Finite Element computed Green’s functions were implemented in a linear joint inversion scheme of geodetic (GPS and InSAR and seismological (strong motion coseismic deformation data. In order to fully exploit the informative power of our dense dataset and to honor the complexities of the real Earth, we implemented an optimized source model, represented by a fault plane subdivided in variable size patches, embedded in a high-resolution realistic three-dimensional model of the Apenninic seismo-tectonic setting, accounting for topographic reliefs and rheological heterogeneities deduced from local tomography. We infer that the investigated inversion domain contains two minima configurations in the solution space, i.e. a single- and a double-patch slip distribution, which are almost equivalent, so that the available datasets and numerical models are not able to univocally discriminate between them. Nevertheless our findings suggest that a two high-slip patch pattern is slightly favoured.

  11. Discussion on Several Problems of Applying GPS and InSAR Technology in Landslide Monitoring%应用GPS与InSAR技术监测滑坡的若干问题讨论

    Institute of Scientific and Technical Information of China (English)



    本文在对滑坡监测的特点进行初步分析的基础上,分别探讨了GPS与InSAR技术在监测滑坡中精度及其存在的问题,并给出了这两种对地观测技术用于监测滑坡的国内外的现状及发展趋势.另外探讨了GPS与InSAR数据融合在滑坡监测中的特点,并分析了GPS与InSAR数据融合的优势.%In this paper, based on preliminary analysis of the characteristics of the landslide monitoring, the accuracy of GPS and inSAR technology in landslide monitoring and its problems were explored respectively, and the domestic and overseas status quo and development trend of these two techniques applied to landslide monitoring were gave. Besides, characteristics of data fusion of GPS and InSAR in landslide monitoring were discussed, and the advantages were analyzed.

  12. Optimized method for atmospheric signal reduction in irregular sampled InSAR time series assisted by external atmospheric information (United States)

    Gong, W.; Meyer, F. J.


    It is well known that spatio-temporal the tropospheric phase signatures complicate the interpretation and detection of smaller magnitude deformation signals or unstudied motion fields. Several advanced time-series InSAR techniques were developed in the last decade that make assumptions about the stochastic properties of the signal components in interferometric phases to reduce atmospheric delay effects on surface deformation estimates. However, their need for large datasets to successfully separate the different phase contributions limits their performance if data is scarce and irregularly sampled. Limited SAR data coverage is true for many areas affected by geophysical deformation. This is either due to their low priority in mission programming, unfavorable ground coverage condition, or turbulent seasonal weather effects. In this paper, we present new adaptive atmospheric phase filtering algorithms that are specifically designed to reconstruct surface deformation signals from atmosphere-affected and irregularly sampled InSAR time series. The filters take advantage of auxiliary atmospheric delay information that is extracted from various sources, e.g. atmospheric weather models. They are embedded into a model-free Persistent Scatterer Interferometry (PSI) approach that was selected to accommodate non-linear deformation patterns that are often observed near volcanoes and earthquake zones. Two types of adaptive phase filters were developed that operate in the time dimension and separate atmosphere from deformation based on their different temporal correlation properties. Both filter types use the fact that atmospheric models can reliably predict the spatial statistics and signal power of atmospheric phase delay fields in order to automatically optimize the filter's shape parameters. In essence, both filter types will attempt to maximize the linear correlation between a-priori and the extracted atmospheric phase information. Topography-related phase components, orbit

  13. Local residue coupling strategies by neural network for InSAR phase unwrapping (United States)

    Refice, Alberto; Satalino, Giuseppe; Chiaradia, Maria T.


    Phase unwrapping is one of the toughest problems in interferometric SAR processing. The main difficulties arise from the presence of point-like error sources, called residues, which occur mainly in close couples due to phase noise. We present an assessment of a local approach to the resolution of these problems by means of a neural network. Using a multi-layer perceptron, trained with the back- propagation scheme on a series of simulated phase images, fashion the best pairing strategies for close residue couples. Results show that god efficiencies and accuracies can have been obtained, provided a sufficient number of training examples are supplied. Results show that good efficiencies and accuracies can be obtained, provided a sufficient number of training examples are supplied. The technique is tested also on real SAR ERS-1/2 tandem interferometric images of the Matera test site, showing a good reduction of the residue density. The better results obtained by use of the neural network as far as local criteria are adopted appear justified given the probabilistic nature of the noise process on SAR interferometric phase fields and allows to outline a specifically tailored implementation of the neural network approach as a very fast pre-processing step intended to decrease the residue density and give sufficiently clean images to be processed further by more conventional techniques.

  14. The Ecosystems SAR (EcoSAR) an Airborne P-band Polarimetric InSAR for the Measurement of Vegetation Structure, Biomass and Permafrost (United States)

    Rincon, Rafael F.; Fatoyinbo, Temilola; Ranson, K. Jon; Osmanoglu, Batuhan; Sun, Guoqing; Deshpande, Manohar D.; Perrine, Martin L.; Du Toit, Cornelis F.; Bonds, Quenton; Beck, Jaclyn; hide


    EcoSAR is a new synthetic aperture radar (SAR) instrument being developed at the NASA/ Goddard Space Flight Center (GSFC) for the polarimetric and interferometric measurements of ecosystem structure and biomass. The instrument uses a phased-array beamforming architecture and supports full polarimetric measurements and single pass interferometry. This Instrument development is part of NASA's Earth Science Technology Office Instrument Incubator Program (ESTO IIP).

  15. Ionospheric effects on repeat-pass SAR interferometry (United States)

    Feng, Jian; Zhen, Weimin; Wu, Zhensen


    InSAR measurements can be significantly affected by the atmosphere when the radar signal propagates through the atmosphere since it varies with space and time. Great efforts have been made in recent years to better understand the properties of the tropospheric effects and to develop methods for mitigating these effects. By using the basic principles of InSAR, the quantitative analysis of ionospheric delay effects on topography and surface deformation have been introduced for the first time. The measurement errors can be related to the vertical ionospheric total electron content (vTEC). By using the ionospheric observations, the effects of temporal ionospheric variations on InSAR have been analyzed. The results indicate that the ionospheric variations with time, season, solar cycle and geomagnetic activities can compromise the effectiveness of InSAR for both the measurement of topography and surface determination. The repeat-pass SAR interferometry errors induced by ionosphere should be corrected by actual measurements.

  16. An unsupervised two-stage clustering approach for forest structure classification based on X-band InSAR data - A case study in complex temperate forest stands (United States)

    Abdullahi, Sahra; Schardt, Mathias; Pretzsch, Hans


    Forest structure at stand level plays a key role for sustainable forest management, since the biodiversity, productivity, growth and stability of the forest can be positively influenced by managing its structural diversity. In contrast to field-based measurements, remote sensing techniques offer a cost-efficient opportunity to collect area-wide information about forest stand structure with high spatial and temporal resolution. Especially Interferometric Synthetic Aperture Radar (InSAR), which facilitates worldwide acquisition of 3d information independent from weather conditions and illumination, is convenient to capture forest stand structure. This study purposes an unsupervised two-stage clustering approach for forest structure classification based on height information derived from interferometric X-band SAR data which was performed in complex temperate forest stands of Traunstein forest (South Germany). In particular, a four dimensional input data set composed of first-order height statistics was non-linearly projected on a two-dimensional Self-Organizing Map, spatially ordered according to similarity (based on the Euclidean distance) in the first stage and classified using the k-means algorithm in the second stage. The study demonstrated that X-band InSAR data exhibits considerable capabilities for forest structure classification. Moreover, the unsupervised classification approach achieved meaningful and reasonable results by means of comparison to aerial imagery and LiDAR data.

  17. Research on positioning of Xi'an ground fissures with InSAR quality map (United States)

    Xu, Li; Zhao, Chao-ying


    Xi'an ground fissure is a typical geo-hazard with nearly half a century history, which have been caused serious damages to roads, building and other civil facilities. Based on the theory of deformation de-correlation of the active ground fissures, this manuscript mainly investigated the positioning method of active ground fissures by analyzing the pseudo-coherence map of adaptively filtered differential interferogram. We took two ERS1 SAR data during 1992-1993 as an example to investigate the active fissures position during this period. Consequently, high consistency between newly detected fissures and the ground fissure map from engineering geological investigation can be achieved.

  18. Derivation of 3-D surface deformation from an integration of InSAR and GNSS measurements based on Akaike's Bayesian Information Criterion (United States)

    Luo, Haipeng; Liu, Yang; Chen, Ting; Xu, Caijun; Wen, Yangmao


    We present a new method to derive 3-D surface deformation from an integration of interferometric synthetic aperture radar (InSAR) images and Global Navigation Satellite System (GNSS) observations based on Akaike's Bayesian Information Criterion (ABIC), considering relationship between deformations of neighbouring locations. This method avoids interpolated errors by excluding the interpolation of GNSS into the same spatial resolution as InSAR images and harnesses the data sets and the prior smooth constraints of surface deformation objectively and simultaneously by using ABIC, which were inherently unresolved in previous studies. In particular, we define surface roughness measuring smoothing degree to evaluate the performance of the prior constraints and deduce the formula of the covariance for the estimation errors to estimate the uncertainty of modelled solution. We validate this method using synthetic tests and the 2008 Mw 7.9 Wenchuan earthquake. We find that the optimal weights associated with ABIC minimum are generally at trade-off locations that balance contributions from InSAR, GNSS data sets and the prior constraints. We use this method to evaluate the influence of the interpolated errors from the Ordinary Kriging algorithm on the derivation of surface deformation. Tests show that the interpolated errors may contribute to biasing very large weights imposed on Kriged GNSS data, suggesting that fixing the relative weights is required in this case. We also make a comparison with SISTEM method, indicating that our method allows obtaining better estimations even with sparse GNSS observations. In addition, this method can be generalized to provide a solution for situations where some types of data sets are lacking and can be exploited further to account for data sets such as the integration of displacements along radar lines and offsets along satellite tracks.

  19. Rupture geometry and slip distribution of the 2016 January 21st Ms6.4 Menyuan, China earthquake inferred from Sentinel-1A InSAR measurements (United States)

    Zhou, Y.


    On 21 January 2016, an Ms6.4 earthquake stroke Menyuan country, Qinghai Province, China. The epicenter of the main shock and locations of its aftershocks indicate that the Menyuan earthquake occurred near the left-lateral Lenglongling fault. However, the focal mechanism suggests that the earthquake should take place on a thrust fault. In addition, field investigation indicates that the earthquake did not rupture the ground surface. Therefore, the rupture geometry is unclear as well as coseismic slip distribution. We processed two pairs of InSAR images acquired by the ESA Sentinel-1A satellite with the ISCE software, and both ascending and descending orbits were included. After subsampling the coseismic InSAR images into about 800 pixels, coseismic displacement data along LOS direction are inverted for earthquake source parameters. We employ an improved mixed linear-nonlinear Bayesian inversion method to infer fault geometric parameters, slip distribution, and the Laplacian smoothing factor simultaneously. This method incorporates a hybrid differential evolution algorithm, which is an efficient global optimization algorithm. The inversion results show that the Menyuan earthquake ruptured a blind thrust fault with a strike of 124°and a dip angle of 41°. This blind fault was never investigated before and intersects with the left-lateral Lenglongling fault, but the strikes of them are nearly parallel. The slip sense is almost pure thrusting, and there is no significant slip within 4km depth. The max slip value is up to 0.3m, and the estimated moment magnitude is Mw5.93, in agreement with the seismic inversion result. The standard error of residuals between InSAR data and model prediction is as small as 0.5cm, verifying the correctness of the inversion results.

  20. Preliminary Study of Ground Movement in Prone Landslide Area by Means of MAI InSAR A Case Study: Ciloto, West Java, Indonesia (United States)

    Hayati, Noorlaila; Riedel, Björn; Niemeier, Wolfgang


    Ciloto is one of the most prone landslide hazard areas in Indonesia. Several landslides in 2012 and 2013 had been recorded in Ciloto and damaged infrastructure around the area. Investigating the history of ground movement along slope area before the landslide happened could support the hazard mitigation in the future. Considering to an efficient surveying method, space-borne SAR processing is the one appropriate way to monitor the phenomenon in past years. The purpose of this study is detecting ground movement using multi-temporal synthetic aperture radar images. We use 13 ALOS PALSAR images from 2007 to 2009 with combination Fine Beam Single (FBS) and Fine Beam Double (FBD) polarization to investigate the slow movement on slope topography. MAI (Multiple Aperture Interferometry) InSAR method is used to analyze the ground movement from both line-of-sight and along-track direction. We split the synthetic aperture into two-looking aperture so that along-track displacement could be created by the difference of forward-backward looking interferograms. With integration of both methods, we could more precisely detect the movement in prone landslide area and achieve two measurements produced by the same interferogram. However, InSAR requires smaller baseline and good temporal baseline between master and slave images to avoid decorellation. There are only several pairs that meet the condition of proper length and temporal baseline indeed the location is also on the agriculture area where is mostly covered by vegetation. The result for two years observation shows that there is insignificant slow movement along slope surface in Ciloto with -2 - -7 cm in range looks or line of sight and 9-40 cm in along track direction. Based on geometry SAR , the most visible detecting of displacement is on the north-west area due to utilization of ascending SAR images.

  1. 25 years of satellite InSAR monitoring of ground instability and coastal geohazards in the archaeological site of Capo Colonna, Italy (United States)

    Cigna, F.; Confuorto, P.; Novellino, A.; Tapete, D.; Di Martire, D.; Ramondini, M.; Calcaterra, D.; Plank, S.; Ietto, F.; Brigante, A.; Sowter, A.


    For centuries the promontory of Capo Colonna in Calabria region, southern Italy, experienced land subsidence and coastline retreat to an extent that the archaeological ruins of the ancient Greek sanctuary are currently under threat of cliff failure, toppling and irreversible loss. Gas extraction in nearby wells is a further anthropogenic element to account for at the regional scale. Exploiting an unprecedented satellite Synthetic Aperture Radar (SAR) time series including ERS-1/2, ENVISAT, TerraSAR-X, COSMO-SkyMed and Sentinel-1A data stacks acquired between 1992 and 2016, this paper presents the first and most complete Interferometric SAR (InSAR) baseline assessment of land subsidence and coastal processes affecting Capo Colonna. We analyse the regional displacement trends, the correlation between vertical displacements with gas extraction volumes, the impact on stability of the archaeological heritage, and the coastal geohazard susceptibility. In the last 25 years, the land has subsided uninterruptedly, with highest annual line-of-sight deformation rates ranging between -15 and -20 mm/year in 2011-2014. The installation of 40 pairs of corner reflectors along the northern coastline and within the archaeological park resulted in an improved imaging capability and higher density of measurement points. This proved to be beneficial for the ground stability assessment of recent archaeological excavations, in an area where field surveying in November 2015 highlighted new events of cliff failure. The conceptual model developed suggests that combining InSAR results, geomorphological assessments and inventorying of wave-storms will contribute to unveil the complexity of coastal geohazards in Capo Colonna.

  2. Post-Eruption Deformation Processes Measured Using ALOS-1 and UAVSAR InSAR at Pacaya Volcano, Guatemala

    Directory of Open Access Journals (Sweden)

    Lauren N. Schaefer


    Full Text Available Pacaya volcano is a persistently active basaltic cone complex located in the Central American Volcanic Arc in Guatemala. In May of 2010, violent Volcanic Explosivity Index-3 (VEI-3 eruptions caused significant topographic changes to the edifice, including a linear collapse feature 600 m long originating from the summit, the dispersion of ~20 cm of tephra and ash on the cone, the emplacement of a 5.4 km long lava flow, and ~3 m of co-eruptive movement of the southwest flank. For this study, Interferometric Synthetic Aperture Radar (InSAR images (interferograms processed from both spaceborne Advanced Land Observing Satellite-1 (ALOS-1 and aerial Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR data acquired between 31 May 2010 and 10 April 2014 were used to measure post-eruptive deformation events. Interferograms suggest three distinct deformation processes after the May 2010 eruptions, including: (1 subsidence of the area involved in the co-eruptive slope movement; (2 localized deformation near the summit; and (3 emplacement and subsequent subsidence of about a 5.4 km lava flow. The detection of several different geophysical signals emphasizes the utility of measuring volcanic deformation using remote sensing techniques with broad spatial coverage. Additionally, the high spatial resolution of UAVSAR has proven to be an excellent compliment to satellite data, particularly for constraining motion components. Measuring the rapid initiation and cessation of flank instability, followed by stabilization and subsequent influence on eruptive features, provides a rare glimpse into volcanic slope stability processes. Observing these and other deformation events contributes both to hazard assessment at Pacaya and to the study of the stability of stratovolcanoes.

  3. History of surface displacements at the Yellowstone Caldera, Wyoming, from leveling surveys and InSAR observations, 1923-2008 (United States)

    Dzurisin, Daniel; Wicks, Charles W.; Poland, Michael P.


    Modern geodetic studies of the Yellowstone caldera, Wyoming, and its extraordinary tectonic, magmatic, and hydrothermal systems date from an initial leveling survey done throughout Yellowstone National Park in 1923 by the U.S. Coast and Geodetic Survey. A repeat park-wide survey by the U.S. Geological Survey (USGS) and the University of Utah during 1975-77 revealed that the central part of the caldera floor had risen more than 700 mm since 1923, at an average rate of 14±1 mm/yr. From 1983 to 2007, the USGS conducted 15 smaller surveys of a single level line that crosses the northeast part of the caldera, including the area where the greatest uplift had occurred from 1923 to 1975-77. The 1983 and 1984 surveys showed that uplift had continued at an average rate of 22±1 mm/yr since 1975-77, but no additional uplift occurred during 1984-85 (-2±5 mm/yr), and during 1985-95 the area subsided at an average rate of 19±1 mm/yr. The change from uplift to subsidence was accompanied by an earthquake swarm, the largest ever recorded in the Yellowstone area (as of March 2012), starting in October 1985 and located near the northwest rim of the caldera. Interferometric synthetic aperture radar (InSAR) images showed that the area of greatest subsidence migrated from the northeast part of the caldera (including the Sour Creek resurgent dome) during 1992-93 to the southwest part (including the Mallard Lake resurgent dome) during 1993-95. Thereafter, uplift resumed in the northeast part of the caldera during 1995-96, while subsidence continued in the southwest part. The onset of uplift migrated southwestward, and by mid-1997, uplift was occurring throughout the entire caldera (essentially rim to rim, including both domes). Consistent with these InSAR observations, leveling surveys indicated 24±3 mm of uplift in the northeast part of the caldera during 1995-98. The beginning of uplift was coincident with or followed shortly after an earthquake swarm near the north caldera rim

  4. Geodetic model of the 2016 Central Italy earthquake sequence inferred from InSAR and GPS measurements (United States)

    Cheloni, Daniele


    On 24th August 2016, a Mw 6.0 earthquake struck a sector of the Apennines in Central Italy, causing extensive damage to the town of Amatrice and several surroundings villages, and killing about 300 inhabitants. The seismic sequence which followed was characterized by numerous aftershocks southeast and northwest of the main event, which decreased in frequency and magnitude until the end of October, when an event of magnitude Mw 5.9 occurred on 26th October about 25 km to the NW of the 24th August event, close to Visso village. In addition, few days later, on 30th October a third great shock of magnitude Mw 6.5, nucleated below the town of Norcia, hit an area encompassing the two previous main events. In order to infer the ground displacement field and to determine the source parameters of the causative faults associated with the three main events of the seismic sequence we exploit the InSAR and GPS coseismic measurements. In particular, we use SAR data acquired by the ALOS-2 (Japanese Aerospace Exploration Agency), Sentinel-1 (European Space Agency) and COSMO-SkyMed (Italian Space Agency) satellites, from both ascending and descending orbits, and data from continuous and survey-mode GPS stations operating during the earthquake sequence. We show that our preferred model is consistent with the activation of at least four main coseismic asperities during the entire sequence, belonging to a SW-dipping normal fault system, the surface expression of which could be associated with the Mt. Gorzano-Mt. Vettore-Mt. Bove alignment. To better simulate the complex deformation pattern associated with the greatest event of the sequence (the 30th October Mw 6.5 Norcia earthquake), additional slip is required by secondary anti- and synthetic faults in the hanging-wall of the main fault, and by a further SW-dipping low-angle fault plane. Finally, we compare the latter retrieved geodetic source with the known geological structures of the Central Apennines; this result may suggest a

  5. Monitoring of Landslide Activity in Slovakia Territory Using Multi-Temporal InSAR Techniques (United States)

    Bakon, M.; Papco, J.; Perissin, D.; Lazecky, M.; Sousa, J. J.; Hlavacova, I.; Batorova, K.; Ondrejka, P.; Liscak, P.; Paudits, P.; Real, N.


    Slope deformations are the most important geohazards in Slovakia which annually cause an extensive economic damage of significant influence. About 22000 slope deformations have been registered so far, covering an area of almost 2600 km2 . Since 2010, 639 new slope failures have been witnessed and their activation was driven mainly by the climatic anomalies such as extraordinary rainfalls. Many of these landslides currently represent a direct threat to the lives, health and property of the residents in the affected areas. The landslide Nizna Mysla is considered to be the second most catastrophic landslide in the history of Slovakia. Damages to buildings and engineering networks had not been identified in the ‘90s of the last century when the first problems with the slope stability appeared. Up-to-now monitoring techniques has currently been reassessed to account for the results from satellite Synthetic Aperture Radar (SAR) techniques.

  6. Steady subsidence of a repeatedly erupting caldera through InSAR observations: Aso, Japan

    KAUST Repository

    Nobile, Adriano


    The relation between unrest and eruption at calderas is still poorly understood. Aso caldera, Japan, shows minor episodic phreatomagmatic eruptions associated with steady subsidence. We analyse the deformation of Aso using SAR images from 1993 to 2011 and compare it with the eruptive activity. Although the dataset suffers from limitations (e.g. atmospheric effects, coherence loss, low signal-to-noise ratio), we observe a steady subsidence signal from 1996 to 1998, which suggests an overall contraction of a magmatic source below the caldera centre, from 4 to 5 km depth. We propose that the observed contraction may have been induced by the release of the magmatic fluids feeding the eruptions. If confirmed by further data, this hypothesis suggests that degassing processes play a crucial role in triggering minor eruptions within open conduit calderas, such as at Aso. Our study underlines the importance of defining any eruptive potential also from deflating magmatic systems with open conduit.

  7. Development and Assessment of an Automated High-Resolution InSAR Volcano-Monitoring System (United States)

    Chowdhury, Tanvir A.; Minet, Christian; Fritz, Thomas


    Monitoring volcanoes and volcanic areas using synthetic aperture radar (SAR) data is a well-established method of risk assessment. However, acquisition planning, ordering, and downloading are time and work intensive, but inevitable process. It has to be done not only once before the actual processing, but for continuous monitoring, it poses a continuous and expensive effort. Therefore an automatic acquisition and processing system is developed at DLR, which allows pseudo-continuous processing of data sequences over the test site and also be applicable to any other optional test-site extension, including the increase of data volume. This system reduces the load of manual work necessary to perform interferometric stacking and quickly gain first information on evolving geophysical processes at the, but not limited to the Italian supersites.

  8. The Impact of Forest Density on Forest Height Inversion Modeling from Polarimetric InSAR Data

    Directory of Open Access Journals (Sweden)

    Changcheng Wang


    Full Text Available Forest height is of great significance in analyzing the carbon cycle on a global or a local scale and in reconstructing the accurate forest underlying terrain. Major algorithms for estimating forest height, such as the three-stage inversion process, are depending on the random-volume-over-ground (RVoG model. However, the RVoG model is characterized by a lot of parameters, which influence its applicability in forest height retrieval. Forest density, as an important biophysical parameter, is one of those main influencing factors. However, its influence to the RVoG model has been ignored in relating researches. For this paper, we study the applicability of the RVoG model in forest height retrieval with different forest densities, using the simulated and real Polarimetric Interferometric SAR data. P-band ESAR datasets of the European Space Agency (ESA BioSAR 2008 campaign were selected for experiments. The test site was located in Krycklan River catchment in Northern Sweden. The experimental results show that the forest density clearly affects the inversion accuracy of forest height and ground phase. For the four selected forest stands, with the density increasing from 633 to 1827 stems/Ha, the RMSEs of inversion decrease from 4.6 m to 3.1 m. The RVoG model is not quite applicable for forest height retrieval especially in sparsely vegetated areas. We conclude that the forest stand density is positively related to the estimation accuracy of the ground phase, but negatively correlates to the ground-to-volume scattering ratio.

  9. An innovative procedure for monitoring the change in soil seismic response by InSAR data: (United States)

    Albano, Matteo; Polcari, Marco; Bignami, Christian; Moro, Marco; Saroli, Michele; Stramondo, Salvatore


    We developed an empirical procedure to evaluate the effect of the ground subsidence on the spatial and temporal seismic response of soils. The proposed method exploits the capabilities of the spaceborne SAR Interferometry technique to detect and map the ground subsidence with unprecedented spatial and temporal coverage. The information provided by satellites is combined with a-priori geological/geotechnical information to assess the soil compaction and the shortening of the soil vibration periods. The procedure was applied to estimate the shortening of the soil resonant period of Mexico City between 2005 and 2013. The results show that in approximately nine years the ground surface has subsided by approximately 0.5⿿3.5 m and the soil resonant period has decreased by approximately 0.1⿿0.4 s. The obtained results, validated with field measurements, highlight the effectiveness of the proposed procedure for the continuous monitoring of the soil resonant periods. The estimated change in resonant period on Mexico City has a great impact on the response spectra used for design, it is then necessary to update the map of the soil resonant period in order to account for the change of dynamic properties of soils caused by subsidence.

  10. Steady subsidence of a repeatedly erupting caldera through InSAR observations: Aso, Japan (United States)

    Nobile, Adriano; Acocella, Valerio; Ruch, Joel; Aoki, Yosuke; Borgstrom, Sven; Siniscalchi, Valeria; Geshi, Nobuo


    The relation between unrest and eruption at calderas is still poorly understood. Aso caldera, Japan, shows minor episodic eruptions, mainly phreatic, associated with steady subsidence. We analyse the recent deformation of Aso using SAR images from 1993 to 2011 and compare this with the eruptive activity. Although the dataset suffers from limitations (e.g., atmospheric effects, coherence loss, low signal to noise ratio), we observe a steady subsidence signal from 1996 to 1998, that suggests an overall contraction of a magmatic source below the caldera centre, from 4.5 to 7 km depth. Because of the similar volumes of the contracting source and erupted material, we propose that the contraction may have been induced by the release of the magmatic fluids feeding the eruptions. If confirmed by further data, this hypothesis suggests that degassing processes play a crucial role in triggering minor eruptions within open conduit calderas, as at Aso. These features underline the importance of defining any eruptive potential also from deflating magmatic systems with open conduit.

  11. Problems and Solutions for InSAR Digital Elevation Model Generation of Mountainous Terrain (United States)

    Eineder, M.


    During the last decade, the techniques to generate digital elevation models (DEM) from SAR interferometry have been demonstrated and refined to a quasi-operational status using data from the ERS tandem mission. With this experience and an improved single-pass system concept, data from the Shuttle Radar Topography Mission (SRTM) acquired in 2000 have been used to produce a global DEM with unprecedented quality. However, under the extreme viewing conditions in mountainous terrain both ERS and SRTM suffer from or even fail due to the radar specific layover and shadow effect that leaves significant areas uncovered and poses severe problems to phase unwrapping. The paper quantifies the areas leading to layover and shadow, and shows innovative ways to overcome shadow and improve phase unwrapping in general. The paper is organized in three major sections. Firstly, the problem to map slopes is addressed in a simplified statistical way. Strategies to optimize the incidence angle for single and multiple observations are proposed. Secondly, a new algorithm is presented that makes the best from shadow by actively using it to help phase unwrapping. Thirdly, an outlook on the use of deltak interferometry for phase unwrapping is given. The paper aims to improve the understanding of the mapping geometry of radar systems and the data currently available and to improve the concepts of future systems and missions.

  12. Present-day strain distribution across a segment of the central bend of the North Anatolian Fault Zone from a Persistent-Scatterers InSAR analysis of the ERS and Envisat archives (United States)

    Peyret, M.; Masson, F.; Yavasoglu, H.; Ergintav, S.; Reilinger, R.


    The North Anatolian Fault Zone (NAFZ) is the major transform system that accommodates the westward movement of the relatively rigid Anatolian block with respect to Eurasia. Mitigating the hazard associated with devastating earthquakes requires understanding how the NAFZ accumulates and releases the potential energy of elastic deformation both in space and in time. In this study, we focus on the central bend of the NAFZ where the strike of the North Anatolian Fault (NAF) changes from N75° to N105° within less than 100 km, and where a secondary fault system veers southwards within the interior of Anatolia. We present interseismic velocity fields obtained from a Persistent-Scatterers (PS) Interferometric radar analysis of ERS and Envisat radar archives. Despite the high vegetation cover, the spatial density of measurements is high (˜10 PS/km2 in average). Interseismic velocities presented below indicate a velocity change of ˜6-8 mm/yr along the satellite line-of-sight (LOS) mainly centred on the NAF surface trace, and are in good agreement with the GPS velocity field published previously. The observed deformation is accommodated within a zone of ˜20 to 30 km width, in this area where no surface creep has been reported, contrary to the Ismetpasa segment located ˜30 km to the west of this study zone. Although less conspicuous, ˜2-3 mm/yr (˜1 mm/yr along the LOS) of the total deformation seems to be localized along the Lacin Fault. The overall agreement with horizontal GPS measurements suggests that the vertical component of the ground deformation is minor. This is confirmed, over the western part of our study zone, by the 3-D estimation of the ground deformation from the combination of the GPS- and the PS-mean velocity fields. However, a specific pattern of the PS velocity fields suggests that an area, enclosed between two faults with roughly south-north orientation, experiences uplift. The PS analyses of radar time-series both prior and posterior to the Izmit

  13. Three-dimensional deformation mapping of a dike intrusion event in Sakurajima in 2015 by exploiting the right- and left-looking ALOS-2 InSAR (United States)

    Morishita, Yu; Kobayashi, Tomokazu; Yarai, Hiroshi


    One of the limitations of the interferometric synthetic aperture radar (InSAR) is its one-dimensional measurement capability. Although three-dimensional (3-D) deformation can be studied if there are three or more measurements with different viewing geometries, it has not been executed because almost all SAR data are acquired using a right-looking geometry. For the Sakurajima volcanic activity on 15 August 2015, ALOS-2 conducted SAR observations from four different viewing directions, ascending/descending and right-/left-looking, enabling the retrieval of 3-D deformation data only from the InSAR results. We have retrieved 3-D deformation with high precision and resolution by a weighted least squares approach. Expansive deformation of over 10 cm has been observed with standard errors of 0.8, 3.4, and 0.7 cm for east-west, north-south, and up-down components, respectively. It is inferred that a dike of 1.7 × 106 m3 volume intruded beneath the Showa crater at a depth of 0.4-1.2 km. In addition to the above-mentioned topic, we will demonstrate that the atmospheric noise has a serious effect on the source modeling and the atmosphere-related noise reduction using numerical weather model has worked well. Acknowledgements: ALOS-2 data were provided from the Volcano Working Group under a cooperative research contract with JAXA. The ownership of ALOS-2 data belongs to JAXA. The products of the numerical weather model and GNSS data were provided by JMA, under the agreement between GSI and JMA.

  14. Extent and distribution of aseismic slip on the Ismetpaşa segment of the North Anatolian Fault (Turkey) from Persistent Scatterer InSAR

    KAUST Repository

    Cetin, Esra


    We use the Persistent Scatterer InSAR (PSI) technique with elastic dislocation models and geology along the creeping section of the North Anatolian Fault (NAF) at Ismetpaşa, to map and deduce the velocity field and the aseismic slip distribution. Revealing the spatiotemporal nature of the creep helped us associate the creep with potential lithological controls, hence providing a new perspective to better understand the underlying causes and mechanisms. The PSI analysis of Envisat ASAR images between 2003 and 2010 reveals a clear picture of surface creep along the fault and a new interseismic velocity field transitioning gradually between the creeping and the locked fault sections. The creep rate is found to fluctuate along a 100 km long section of the fault in a manner similar to that along the Hayward fault, reaching a maximum of ∼20±2 mm/yr, close to the far field plate velocity (∼25±1.5 mm/yr). At Ismetpaşa, it is in the range of 8±2 mm/yr, consistent with the previous geodetic observations. The creeping section appears to extend 30 km further east than those previously reported. Modeling of the PSI data reveals a heterogeneous creep distribution at depth with two main patches confined mostly to the uppermost 5 km portion of the seismogenic crust, releasing annually 6.2 × 1016 Nm (Mw=5.1) geodetic moment. Our analysis combined with previous studies suggests that creep might have commenced as postseismic deformation following the 1944 earthquake and has evolved to stable fault creep with time. There is a correlation between aseismic surface creep and the geology along the fault as it is in major part associated to rocks with low frictional strength such as the andesitic-basaltic, limestone, and serpentine bodies within the fault zone. © 2014. American Geophysical Union. All Rights Reserved.

  15. The 2010 MW 6.9 Yushu (Qinghai, China) earthquake: constraints from InSAR, bodywave modeling and satellite imagery (United States)

    Parsons, B. E.; Li, Z.; Elliott, J. R.; Barisin, I.; Feng, W.; Jackson, J. A.; Song, X.; Walters, R. J.; Zhang, P.


    A large earthquake (MW = 6.9) struck the county of Yushu, Qinghai, China on 13 April 2010, causing 2,220 fatalities and over 12,000 injured. We have used a combination of ALOS and Envisat SAR data to model the fault geometry and slip distribution of this event, using high-resolution satellite imagery and bodywave modelling to provide further information. Preliminary observations were first posted on the internet on 20 April 2010. The fault on which the earthquake occurred can be traced precisely using SPOT 5 (2.5 m resolution) imagery and SAR image offsets, interferometric coherence and phase discontinuities. On this basis the fault was most simply divided into three segments. The dips of the fault segments were obtained from elastic dislocation models with uniform slip; the southeast segment, on which the largest slip occurred, and northwest segment are near vertical, with the central segment dipping about 75° to the southwest. Slip was almost pure left-lateral. The fault geometry was then fixed and the slip distribution that best-fits the InSAR phase measurements determined. Slip occurs mainly in the upper 10 km, with a maximum slip of ~2 m at a depth of 3 km on the southeast segment. Near-surface slip (upper 1 km of the model) agrees well with field observations of offsets on the southeast segment. The geodetically-determined and seismic moments are in reasonable agreement (2.1 ± 0.2 × 1019 N m). However, rupture lengths of 35-40 km were estimated immediately after the earthquake from the seismic moment together with a magnitude of slip from surface observations and assumed seismogenic layer thicknesses, whereas the interferograms showed slip must have occurred over a length of 70-75 km. The apparent discrepancy can be explained in terms of the non-uniform distribution of moment release on the fault. There are three main patches of moment release along the length of the fault. We believe the northwest patch may be due to the aftershock (M0 = ~0.2 × 1019 N m

  16. Identification of active release planes using ground-based differential InSAR at the Randa rock slope instability, Switzerland

    Directory of Open Access Journals (Sweden)

    V. Gischig


    Full Text Available Five ground-based differential interferometric synthetic aperture radar (GB-DInSAR surveys were conducted between 2005 and 2007 at the rock slope instability at Randa, Switzerland. Resultant displacement maps revealed, for the first time, the presence of an active basal rupture zone and a lateral release surface daylighting on the exposed 1991 failure scarp. Structures correlated with the boundaries of interferometric displacement domains were confirmed using a helicopter-based LiDAR DTM and oblique aerial photography. Former investigations at the site failed to conclusively detect these active release surfaces essential for kinematic and hazard analysis of the instability, although their existence had been hypothesized. The determination of the basal and lateral release planes also allowed a more accurate estimate of the currently unstable volume of 5.7±1.5 million m3. The displacement patterns reveal that two different kinematic behaviors dominate the instability, i.e. toppling above 2200 m and translational failure below. In the toppling part of the instability the areas with the highest GB-DInSAR displacements correspond to areas of enhanced micro-seismic activity. The observation of only few strongly active discontinuities daylighting on the 1991 failure surface points to a rather uniform movement in the lower portion of the instability, while most of the slip occurs along the basal rupture plane. Comparison of GB-DInSAR displacements with mapped discontinuities revealed correlations between displacement patterns and active structures, although spatial offsets occur as a result of the effective resolution of GB-DInSAR. Similarly, comparisons with measurements from total station surveys generally showed good agreement. Discrepancies arose in several cases due to local movement of blocks, the size of which could not be resolved using GB-DInSAR.

  17. Interpolation of GPS and Geological Data Using InSAR Deformation Maps: Method and Application to Land Subsidence in the Alto Guadalentín Aquifer (SE Spain

    Directory of Open Access Journals (Sweden)

    Marta Béjar-Pizarro


    Full Text Available Land subsidence resulting from groundwater extractions is a global phenomenon adversely affecting many regions worldwide. Understanding the governing processes and mitigating associated hazards require knowing the spatial distribution of the implicated factors (piezometric levels, lithology, ground deformation, usually only known at discrete locations. Here, we propose a methodology based on the Kriging with External Drift (KED approach to interpolate sparse point measurements of variables influencing land subsidence using high density InSAR measurements. In our study, located in the Alto Guadalentín basin, SE Spain, these variables are GPS vertical velocities and the thickness of compressible soils. First, we estimate InSAR and GPS rates of subsidence covering the periods 2003–2010 and 2004–2013, respectively. Then, we apply the KED method to the discrete variables. The resulting continuous GPS velocity map shows maximum subsidence rates of 13 cm/year in the center of the basin, in agreement with previous studies. The compressible deposits thickness map is significantly improved. We also test the coherence of Sentinel-1 data in the study region and evaluate the applicability of this methodology with the new satellite, which will improve the monitoring of aquifer-related subsidence and the mapping of variables governing this phenomenon.

  18. Graben Formation and Dike Arrest during the 2009 Harrat Lunayyir Dike Intrusion in Saudi Arabia: Insights from InSAR, Stress Calculations and Analog Experiments

    KAUST Repository

    Xu, Wenbin


    Detailed spatial and temporal accounts of propagating dikes from crustal deformation data, including their interplay with faulting, are rare, leaving many questions about how this interplay affects graben formation and the arrest of dikes unanswered. Here we use InSAR observations, stress calculations and analog experiments to investigate the interaction between an intruding dike and normal faulting during the 2009 Harrat Lunayyir dike intrusion in western Saudi Arabia. We generated five displacement maps from InSAR data to unravel the temporal evolution of deformation covering the majority of the intrusion. We find that the observed surface displacements can be modeled by a ~2-m-thick dike with an upper tip ~2 km below the surface on 16 May 2009, four weeks after the onset of seismic unrest. In the following three days, the dike propagated to within ~1 km of the surface with graben-bounding normal faulting dominating the near-field deformation. The volume of the dike doubled between mid-May and mid-June. We carried out analog experiments that indicate that the wedge-shaped graben grew outwards with the faulting style changing progressively from normal faulting to oblique. Coulomb failure stress change calculations show that the intruding dike caused two zones of shallow horizontal tension on both sides of the dike, producing two zones of fissuring and normal faulting at the surface. In return, the faulting provoked compression around the upper tip of the dike, holding back its vertical propagation.

  19. Graben formation and dike arrest during the 2009 Harrat Lunayyir dike intrusion in Saudi Arabia: Insights from InSAR, stress calculations and analog experiments (United States)

    Xu, Wenbin; Jónsson, Sigurjón; Corbi, Fabio; Rivalta, Eleonora


    Detailed spatial and temporal accounts of propagating dikes from crustal deformation data, including their interplay with faulting, are rare, leaving many questions about how this interplay affects graben formation and the arrest of dikes unanswered. Here we use interferometric synthetic aperture radar (InSAR) observations, stress calculations, and analog experiments to investigate the interaction between an intruding dike and normal faulting during the 2009 Harrat Lunayyir dike intrusion in western Saudi Arabia. We generated five displacement maps from InSAR data to unravel the temporal evolution of deformation covering the majority of the intrusion. We find that the observed surface displacements can be modeled by a ~2 m thick dike with an upper tip ~2 km below the surface on 16 May 2009, 4 weeks after the onset of seismic unrest. In the following three days, the dike propagated to within ~1 km of the surface with graben-bounding normal faulting dominating the near-field deformation. The volume of the dike doubled between mid-May and mid-June. We carried out analog experiments that indicate that the wedge-shaped graben grew outward with the faulting style changing progressively from normal faulting to oblique. Coulomb failure stress change calculations show that the intruding dike caused two zones of shallow horizontal tension on both sides of the dike, producing two zones of fissuring and normal faulting at the surface. In return, the faulting provoked compression around the upper tip of the dike, holding back its vertical propagation.

  20. Surface motion of active rock glaciers in the Sierra Nevada, California, USA: inventory and a case study using InSAR

    Directory of Open Access Journals (Sweden)

    L. Liu


    Full Text Available Despite the abundance of rock glaciers in the Sierra Nevada of California, USA, few efforts have been made to measure their surface flow. Here we use the interferometric synthetic aperture radar (InSAR technique to compile a benchmark inventory describing the kinematic state of 59 active rock glaciers in this region. In the late summer of 2007, these rock glaciers moved at speeds that range from 14 cm yr−1 to 87 cm yr−1, with a regional mean value of 53 cm yr−1. Our inventory reveals a spatial difference: rock glaciers in the southern Sierra Nevada moved faster than the ones in the central Sierra Nevada. In addition to the regional mapping, we also conduct a case study to measure the surface flow of the Mount Gibbs rock glacier in fine spatial and temporal detail. The InSAR measurements over this target reveal (1 that the spatial pattern of flow is correlated with surface geomorphic features and (2 a significant seasonal variation of flow speed whose peak value was 48 cm yr−1in the fall of 2007, more than twice the minimum value observed in the spring of 2008. The seasonal variation lagged air temperatures by three months. Our finding on the seasonal variation of surface speed reinforces the importance of a long time series with high temporal sampling rates to detect possible long-term changes of rock glacier kinematics in a warming climate.

  1. Seven years of postseismic deformation following the 2003 Mw = 6.8 Zemmouri earthquake (Algeria) from InSAR time series

    KAUST Repository

    Cetin, Esra


    We study the postseismic surface deformation of the Mw 6.8, 2003 Zemmouri earthquake (northern Algeria) using the Multi-Temporal Small Baseline InSAR technique. InSAR time series obtained from 31 Envisat ASAR images from 2003 to 2010 reveal sub-cm coastline ground movements between Cap Matifou and Dellys. Two regions display subsidence at a maximum rate of 2 mm/yr in Cap Djenet and 3.5 mm/yr in Boumerdes. These regions correlate well with areas of maximum coseismic uplifts, and their association with two rupture segments. Inverse modeling suggest that subsidence in the areas of high coseismic uplift can be explained by afterslip on shallow sections (<5 km) of the fault above the areas of coseismic slip, in agreement with previous GPS observations. The earthquake impact on soft sediments and the ground water table southwest of the earthquake area, characterizes ground deformation of non-tectonic origin. The cumulative postseismic moment due to 7 years afterslip is equivalent to an Mw 6.3 earthquake. Therefore, the postseismic deformation and stress buildup has significant implications on the earthquake cycle models and recurrence intervals of large earthquakes in the Algiers area.

  2. Fault source modeling of October 28, 2008 earthquake sequence in Baluchistan, Pakistan, on the basis of ALOS/PALSAR InSAR data (United States)

    Usman, M.; Furuya, M.


    The Quetta Syntaxis in the western Baluchistan, Pakistan, serves as a junction for different thrust faults. As this area also lays close to the left lateral strike slip Chaman fault, which is supposed to be marking the boundary between Indian and Eurasian plate, thus the resulting seismological behavior of this regime becomes much more complex. In the region of Quetta Syntaxis, below the fold and thrust belt of Suleiman and Kirthar ranges and on 28 October 2008, there stroke an earthquake of magnitude 6.4 (Mw) which was followed by a doublet on the very next day. In association with these major events, there have been four more shocks, one foreshock and three aftershocks that have moment magnitude greater than 5. On the basis of seismological, GPS and ENVISAT/ASAR InSAR data many researchers tried to explain the source of this sequence. The latest source modeling results, on the basis of ENVISAT/ASAR data has provided an insight about the complexity of tectonics in the study area. However, in comparison to ALOS/PALSAR InSAR data, ENVISAT/ASAR has lacked signals near the epicentral area because of the low coherence. Probably, it has led to different interpretations by different researchers even on the basis of same satellite data. By using ALOS/PALSAR data, we have suggested a four faults model, two left laterals and two right laterals, which also retains the most desirable features of previous models.

  3. Rupture Geometry and Slip Associated With the 2007 November 14 Mw = 7.7 Tocopilla (Chile) Earthquake, as Preliminary Determined by InSAR and GPS Observations (United States)

    Béjar-Pizarro, M.; Carrizo, D.; Socquet, A.; Armijo, R.; de Chabalier, J. B.; Nercessian, A.; Charade, O.; Ruegg, J. C.; Barrientos, S.; Campos, J.


    A Mw 7.7 subduction earthquake occurred on November 14, 2007 in Tocopilla (northern Chile). This region (between 16.5°S and 23.5°S) had been identified as major seismic gap (~1000 km length) that had not ruptured since the occurrence of the South Peru (Mw = 9.1, 16 August 1868) and the Iquique (Mw = 9.0, 10 May 1877) megathrust earthquakes. This gap was reduced to a length of ~500 km after the occurrence of the Arequipa (Mw = 8.3, 23 June 2001) and the Antofagasta (Mw = 8.1, 30 July 1995) earthquakes. The Tocopilla earthquake occurred within a network of continuous GPS stations operated by IPGP, Caltech, DGF and IRD. An array of 21 benchmarks, installed and previously measured periodically by IPGP/DGF, was resurveyed after the earthquake, increasing the spatial density of static observations of the surface displacement. We combine space geodesy (InSAR and GPS) data of surface displacement to determine the geometry and kinematics of the rupture on the subduction interface. The deformation pattern in the interferogram constrains the E-W extension of the fault plane. Comparison of the InSAR data of the 2007 Tocopilla and 1995 Antofagasta earthquakes documents clearly the shift in rupture depth between the two events. The Tocopilla rupture apparently extended between 50- 55 and 30-35 km depth and did not propagate up to the surface. Interestingly, the earthquake definitely ruptured the deeper part of the seismogenic interface, well into the transition zone that was identified earlier (Chlieh et al., 2004). Most of the aftershocks following the 2007 event were concentrated near the southern end of the rupture that is clearly defined by the GPS and InSAR data to the north of the Mejillones Peninsula. The region of the subduction zone under the Mejillones Peninsula appears to act as a barrier arresting rupture of large earthquakes (1877, 1995 and 2007 earthquakes). When exploring the details of the rupture on the subduction interface, geodetic data require two distinct

  4. Simultaneous estimation of the dip angles and slip distribution on the faults of the 2016 Kumamoto earthquake through a weak nonlinear inversion of InSAR data (United States)

    Fukahata, Yukitoshi; Hashimoto, Manabu


    At the 2016 Kumamoto earthquake, surface ruptures were observed not only along the Futagawa fault, where main ruptures occurred, but also along the Hinagu fault. To estimate the slip distribution on these faults, we extend a method of nonlinear inversion analysis (Fukahata and Wright in Geophys J Int 173:353-364, 2008) to a two-fault system. With the method of Fukahata and Wright (2008), we can simultaneously determine the optimal dip angle of a fault and the slip distribution on it, based on Akaike's Bayesian information criterion by regarding the dip angle as an hyperparameter. By inverting the InSAR data with the developed method, we obtain the dip angles of the Futagawa and Hinagu faults as 61° ± 6° and 74° ± 12°, respectively. The slip on the Futagawa fault is mainly strike slip. The largest slip on it is over 5 m around the center of the model fault (130.9° in longitude) with a significant normal slip component. The slip on the Futagawa fault quickly decreases to zero beyond the intersection with the Hinagu fault. On the other hand, the slip has a local peak just inside Aso caldera, which would be a cause of severe damage in this area. A relatively larger reverse fault slip component on a deeper part around the intersection with Aso caldera suggests that something complicated happened there. The slip on the Hinagu fault is almost a pure strike slip with a peak of about 2.4 m. The developed method is useful in clarifying the slip distribution, when a complicated rupture like the Kumamoto earthquake happens in a remote area.[Figure not available: see fulltext.

  5. InSAR measurements for the 2014 Mw 6.0 Jinggu, Yunnan Earthquake (United States)

    Chen, Jiajun; Feng, Wanpeng; Sergey, Samsonov; Mahdi, Motagh; Li, Zhenhong; Clarke, Peter


    An earthquake occurred in the southwest of Yunnan, China on 7 October 2014 at 21:49 local time, measured as Mw 6.0 by the United States Geological Survey and Mw 6.1 by the European Alert System. Strong earthquakes are common in this region because of the continental collision between the India and Eurasia plates with a relative convergence rate of 40-50 mm/yr. A detailed study of this earthquake will therefore allow better understanding of regional fault properties. For the first time, Radarsat-2 (RS2) data was employed to investigate co-seismic surface movements of this event. Two ascending RS2 images acquired on 2 October 2014 and 19 November 2014 were used to generate an interferogram, revealing line-of-sight (LOS) displacements with a maximum value of 0.13 m (towards the satellite) in the NW sector. We use PSOKINV to determine fault geometric parameters and slip distribution. First, fault parameters are determined using improved particle swarm optimization. Second, slip distribution over the fault plane is retrieved using an iterative strategy for estimating optimal dip angle and smoothing factors [Feng et al., 2013]. The comparison between the modelled LOS changes and the measured ones shows a good fit, with residuals smaller than 0.02 m. The best-fitting model suggests that the rupture occurred on a left-lateral strike-slip fault with a strike of 323°. The total released moment is equivalent to Mw 6.1 and the main slip zone is confined between depths of 2-8 km. A maximum slip of 1.1 m appears at a depth of 4.3 km, with a rupture length of about 10km. Reference: Feng, W., Z. Li, J. R. Elliott, Y. Fukushima, T. Hoey, A. Singleton, R. Cook, and Z. Xu (2013), The 2011 MW 6.8 Burma earthquake: fault constraints provided by multiple SAR techniques, Geophysical Journal International, doi:10.1093/gji/ggt254.

  6. InSAR measurement of surface deformation at the Hanford Reservation associated with the 2009 Wooded Island earthquake swarm (Invited) (United States)

    Wicks, C. W.; Gomberg, J. S.; Weaver, C. S.


    Earthquake swarms are frequent in much of eastern Washington. Earthquakes in these swarms typically are in the range of magnitude 1 to 3 and are often shallow with depths of a few kilometers. The most recent swarm of small earthquakes occurred from January 2009 through July 2009 and was located near Wooded Island 15 km north of Richland, Washington on the southeastern corner of the Hanford Reservation. The swarm location is along the eastern edge of the Yakima Fold and Thrust Belt, where swarm activity appears to be common. The Wooded Island swarm location is about 10 km northeast of the northwest-striking Rattlesnake Mountain fault and about 10 km south of the Gable Mountain fault that strikes west-northwest. Both of these mapped faults are associated with major thrusts that deform the Columbia River basalts, but the relation between these faults and the current swarm location is unknown. Although there have been at least two other swarms near Wooded Island in the last 30 years, the current swarm is of particular interest because we are able to map the surface deformation associated with the swarm with multi-temporal InSAR images from the European Space Agency’s ENVISAT satellite. We find two clear “pods” of deformation in interferograms generated from the satellite data, coincident with the distribution of the swarm hypocenters. We measure about 35 mm of peak surface deformation in the satellite line-of-sight direction. The deformation became resolvable in interferograms after the end of February 2009, when seismicity rates were highest. Preliminary modeling of the deformation is consistent with two small (about two km long) reverse faults each striking west-northwest with nearly 50 mm of slip. The geodetically estimated slip exceeds the seismic slip significantly, suggesting that the swarm was driven by aseismic creep. One of the modeled faults is well constrained to be shallow, about 200 m deep, and both faults occur within the underlying ~3 km thick

  7. Dynamic deformation of Seguam Island, Alaska, 1992--2008, from multi-interferogram InSAR processing (United States)

    Lee, Chang-Wook; Lu, Zhong; Won, Joong-Sun; Jung, Hyung-Sup; Dzurisin, Daniel


    We generated a time-series of ERS-1/2 and ENVISAT interferometric synthetic aperture radar (InSAR) images to study ground surface deformation at Seguam Island from 1992 to 2008. We used the small baseline subset (SBAS) technique to reduce artifacts associated with baseline uncertainties and atmospheric delay anomalies, and processed images from two adjacent tracks to validate our results. Seguam Island comprises the remnants of two late Quaternary calderas, one in the western caldera of the island and one in the eastern part of the island. The western caldera subsided at a constant rate of ~ 1.6 cm/yr throughout the study period, while the eastern caldera experienced alternating periods of subsidence and uplift: ~ 5 cm/year uplift during January 1993–October 1993 (stage 1), ~ 1.6 cm/year subsidence during October 1993–November 1998 (stage 2), ~ 2.0 cm/year uplift during November 1998–September 2000 (stage 3), ~ 1.4 cm/year subsidence during September 2000–November 2005 (stage 4), and ~ 0.8 cm/year uplift during November 2005– July 2007 (stage 5). Source modeling indicates a deflationary source less than 2 km below sea level (BSL) beneath the western caldera and two sources beneath the eastern caldera: an inflationary source 2.5–6.0 km BSL and a deflationary source less than 2 km BSL. We suggest that uplift of the eastern caldera is driven by episodic intrusions of basaltic magma into a poroelastic reservoir 2.5–6.0 km BSL beneath the caldera. Cooling and degassing of the reservoir between intrusions results in steady subsidence of the overlying surface. Although we found no evidence of magma intrusion beneath the western caldera during the study period, it is the site (Pyre Peak) of all historical eruptions on the island and therefore cooling and degassing of intrusions presumably contributes to subsidence there as well. Another likely subsidence mechanism in the western caldera is thermoelastic contraction of lava flows emplaced near Pyre Peak during

  8. Along-strike variations of the partitioning of convergence across the Haiyuan fault system detected by InSAR (United States)

    Daout, S.; Jolivet, R.; Lasserre, C.; Doin, M.-P.; Barbot, S.; Tapponnier, P.; Peltzer, G.; Socquet, A.; Sun, J.


    Oblique convergence across Tibet leads to slip partitioning with the coexistence of strike-slip, normal and thrust motion on major fault systems. A key point is to understand and model how faults interact and accumulate strain at depth. Here, we extract ground deformation across the Haiyuan Fault restraining bend, at the northeastern boundary of the Tibetan plateau, from Envisat radar data spanning the 2001-2011 period. We show that the complexity of the surface displacement field can be explained by the partitioning of a uniform deep-seated convergence. Mountains and sand dunes in the study area make the radar data processing challenging and require the latest developments in processing procedures for Synthetic Aperture Radar interferometry. The processing strategy is based on a small baseline approach. Before unwrapping, we correct for atmospheric phase delays from global atmospheric models and digital elevation model errors. A series of filtering steps is applied to improve the signal-to-noise ratio across high ranges of the Tibetan plateau and the phase unwrapping capability across the fault, required for reliable estimate of fault movement. We then jointly invert our InSAR time-series together with published GPS displacements to test a proposed long-term slip-partitioning model between the Haiyuan and Gulang left-lateral Faults and the Qilian Shan thrusts. We explore the geometry of the fault system at depth and associated slip rates using a Bayesian approach and test the consistency of present-day geodetic surface displacements with a long-term tectonic model. We determine a uniform convergence rate of 10 [8.6-11.5] mm yr-1 with an N89 [81-97]°E across the whole fault system, with a variable partitioning west and east of a major extensional fault-jog (the Tianzhu pull-apart basin). Our 2-D model of two profiles perpendicular to the fault system gives a quantitative understanding of how crustal deformation is accommodated by the various branches of this

  9. Integrating geomorphological mapping, InSAR, GPR and trenching for the identification and investigation of buried sinkholes in the mantled evaporite karst of the Ebro Valley (NE Spain) (United States)

    Gutiérrez, Francisco; Galve, Jorge Pedro; Lucha, Pedro; Bonachea, Jaime; Castañeda, Carmen


    bedrock sagging. (2) Around 70% of the sinkholes have been filled by man-made ground. (3) Subsidence has caused severe damage to many human structures, primarily due to the ongoing activity of pre-existing buried sinkholes. Consequently, the identification of sinkholes is the key for preventive planning and the delineation of the main risk areas. A total of eleven sinkholes (S1-S11) covering around 20% of the study area were mapped. Six of the sinkholes were buried and the largest one (S8), which occupies approximately 35,500 m2, partially coincides with the area previously selected for the construction of a housing state. The investigation was developed in three main phases. A preliminary sinkhole map was produced in phase I using: (a) aerial photographs and satellite images from different dates (1927, 1957, 1984, 2003, 2006, 2007), (b) detailed topographical maps from 1969 (1:2000) and 1971-73 (1:1000) with contour intervals of 1 m, (c) thorough field surveys including interviews to local people and inspection to human structures, and (d) radar interferometry. Deformation measurements were obtained from 54 interferograms generated by means of the Stable Point Network technique with 23 ENVISAT images acquired from May 2003 to July 2008. The InSAR analysis provides data on the temporal evolution of the subsidence (magnitude and rate) for coherent 20 m-sized pixels. During phase II, 26 GPR profiles with a total length of 2,290 m were conducted using a 400 MHz antenna. In phase III, 13 backhoe trenches up to 2.8 m deep and totalling 323 m were investigated following the methodology commonly used in paleoseismological studies. Two samples were obtained for radiocarbon dating in a trench dug at the margin of sinkhole S8. The aerial photographs, specially the stereoscopic images taken in 1957, were the most useful tool for the identification of buried sinkholes. They allowed us the detection of 9 sinkholes out of 11. The topographical maps depict 7 of the inventoried sinkholes

  10. Post-emplacement cooling and contraction of lava flows: InSAR observations and thermal model for lava fields at Hekla volcano, Iceland (United States)

    Wittmann, Werner; Dumont, Stephanie; Lavallee, Yan; Sigmundsson, Freysteinn


    Gradual post-emplacement subsidence of lava flows has been observed at various volcanoes, e.g. Okmok volcano in Alaska, Kilauea volcano on Hawaii and Etna volcano on Sicily. In Iceland, this effect has been observed at Krafla volcano and Hekla volcano. The latter was chosen as a case study for investigating subsidence mechanisms, specifically thermal contraction. Effects like gravitational loading, clast repacking or creeping of a hot and liquid core can contribute to subsidence of emplaced lava flows, but thermal contraction is considered being a crucial effect. The extent to which it contributes to lava flow subsidence is investigated by mapping the relative movement of emplaced lava flows and flow substrate, and modeling the observed signal. The slow vegetation in Iceland is advantageous for Interferometric Synthetic Aperture Radar (InSAR) and offers great coherence over long periods after lava emplacement, expanding beyond the outlines of lava flows. Due to this reason, InSAR observations over volcanoes in Iceland have taken place for more than 20 years. By combining InSAR tracks from ERS, Envisat and Cosmo-SkyMed satellites we gain six time series with a total of 99 interferograms. Making use of the high spatial resolution, a temporal trend of vertical lava movements was investigated over a course of over 23 years over the 1991 lava flow of Hekla volcano, Iceland. From these time series, temporal trends of accumulated subsidence and subsidence velocities were determined in line of sight of the satellites. However, the deformation signal of lava fields after emplacement is vertically dominated. Subsidence on this lava field is still ongoing and subsidence rates vary from 14.8 mm/year in 1995 to about 1.0 mm/year in 2014. Fitting a simple exponential function suggests a exponential decay constant of 5.95 years. Additionally, a one-dimensional, semi-analytical model was fitted to these data. While subsidence due to phase change is calculated analytically

  11. Slip distribution of the 2015 September 16, Illapel (Chile) Mw 8.3 earthquake from joint inversion of tsunami and InSAR data (United States)

    Piatanesi, Alessio; Romano, Fabrizio; Lorito, Stefano; Tolomei, Cristiano; Atzori, Simone


    On September 16, 2015 an Mw 8.3 interplate earthquake occurred offshore the Illapel region, Chile, approximately in the area of the 1943 Mw 8.1 earthquake. The epicenter is located at 71.7 °W, 31.6 °S at a depth of ~25 km. In this region the Nazca Plate is subducting under the South America Plate with a convergence rate of ˜74mm/yr. This earthquake generated a tsunami that struck the Chilean coast from ~24 °S to ~38 °S, with particularly severe damages around the area of Coquimbo city where a tide gauge recorded a maximum tsunami wave amplitude of ~4.7 m. The tsunami has been distinctly recorded by several tide gauges distributed along the Chilean coast and also by some DART buoys located in the South Pacific ocean. The inland coseismic deformation has been detected through InSAR processing of Sentinel-1 images, acquired from ascending and descending orbits. In this work we present the slip distribution of the earthquake obtained by jointly inverting the tsunami waveforms recorded by 3 DART buoys and 15 tide gauges, and the ground displacement retrieved by InSAR data. In order to honour the geometry of the subducting plate, we use a fault model that accounts for the variability of the strike and dip angles along the slipping surface composed by 20x20 km subfaults. We use the Green's function approach and a simulated annealing technique to solve the inverse problem. Synthetic checkerboard tests indicate that tsunami and InSAR data well constrain the offshore and onshore part of the slip distribution respectively, whereas the overall target slip distribution is well recovered by jointly using the two datasets. The slip distribution of the Illapel event features a main patch of slip updip of the hypocenter, extending for ~200 km along strike, ~120 km along dip and reaching the trench with a maximum slip of ~9 m; the slip direction is ~110°, pretty consistent with the relative convergence axis between the Nazca and the South America Plates. We also observe a

  12. Integrated Analysis of Interferometric SAR, Satellite Altimetry and Hydraulic Modeling to Quantify Louisiana Wetland Dynamics (United States)

    Lee, Hyongki; Kim, Jin-woo; Lu, Zhong; Jung, Hahn Chul; Shum, C. K.; Alsdorf, Doug


    Wetland loss in Louisiana has been accelerating due primarily to anthropogenic and nature processes, and is being advocated as a problem with national importance. Accurate measurement or modeling of wetland-wide water level changes, its varying extent, its storage and discharge changes resulting in part from sediment loads, erosion and subsidence are fundamental to assessment of hurricane-induced flood hazards and wetland ecology. Here, we use innovative method to integrate interferometric SAR (InSAR) and satellite radar altimetry for measuring absolute or geocentric water level changes and applied the methodology to remote areas of swamp forest in coastal Louisiana. Coherence analysis of InSAR pairs suggested that the HH polarization is preferred for this type of observation, and polarimetric analysis can help to identi:fy double-bonnce backscattering areas in the wetland. Envisat radar altimeter-measured 18- Hz (along-track sampling of 417 m) water level data processed with regional stackfile method have been used to provide vertical references for water bodies separated by levees. The high-resolution (approx.40 m) relative water changes measured from ALOS PALSAR L-band and Radarsat-l C-band InSAR are then integrated with Envisat radar altimetry to obtain absolute water level. The resulting water level time series were validated with in situ gauge observations within the swamp forest. Furthermore, we compare our water elevation changes with 2D flood modeling from LISFLOOD hydrodynamic model. Our study demonstrates that this new technique allows retrospective reconstruction and concurrent monitoring of water conditions and flow dynamics in wetlands, especially those lacking gauge networks.

  13. - and Syn-Eruptive Surface Movements of Azerbaijan Mud Volcanoes Detected Through Insar Analysis: Preliminary Results (United States)

    Antonielli, Benedetta; Monserrat, Oriol; Bonini, Marco; Righini, Gaia; Sani, Federico; Luzi, Guido; Feyzullayev, Akper; Aliyev, Chingiz


    Mud volcanism is a process that consists in the extrusion of mud, fragments or blocks of country rocks, saline waters and gases, mostly methane. This mechanism is typically linked to in-depth hydrocarbon traps, and it builds up a variety of conical edifices with dimension and morphology similar to those of magmatic volcanoes. Interferometry by Satellite Aperture Radar (InSAR) techniques have been commonly used to monitor and investigate the ground deformation connected to the eruptive phases of magmatic volcanoes. InSAR techniques have also been employed to explore the ground deformation associated with the LUSI mud volcano in Java (Indonesia). We aim to carry out a study on the paroxysmal activities of the Azerbaijan mud volcanoes, among the largest on Earth, using similar techniques. In particular the deformations of the mud volcanic systems were analyzed through the technique of satellite differential interferometry (DInSAR), thanks to the acquisition of 16 descending and 4 ascending Envisat images, spanning about 4 years (October 2003-November 2007); these data were provided by the European Space Agency. The preliminary analysis of a set of 77 interferograms and the unwrapping process elaboration of some of them selected according to the best coherence values, allowed the detection of significant deformations in correspondence of Ayaz-Akhtarma and Khara Zira Island mud volcanoes. This analysis has allowed to identify relevant ground deformations of the volcanic systems in connection with the main eruptive events in 2005 and in 2006 respectively, that are recorded by the catalogue of Azerbaijan mud volcano eruptions until 2007. The preliminary analysis of the interferograms of the Ayaz-Akhtarma and the Khara Zira mud volcanoes shows that the whole volcano edifice or part of it is subject to a ground displacement before or in coincidence with the eruption. Assuming that the movement is mainly vertical, we suppose that deformation is due to bulging of the volcanic

  14. Geohazards Monitoring in Roma from InSAR and In Situ Data: Outcomes of the PanGeo Project (United States)

    Comerci, Valerio; Vittori, Eutizio; Cipolloni, Carlo; Di Manna, Pio; Guerrieri, Luca; Nisio, Stefania; Succhiarelli, Claudio; Ciuffreda, Maria; Bertoletti, Erika


    Within the PanGeo project (financed by the European Commission under the 7th Framework Program), the Geological Survey of Italy ( ISPRA) and the Urban Planning Department of the City of Roma developed a geodatabase and map of the geological hazards for the territory of Roma, integrating remotely sensed data (PSInSAR—Permanent Scatterer Interferometry Synthetic Aperture Radar) and in situ geological information. Numerous thematic layers, maps and inventories of hazards (e.g., landslides, sinkholes, cavities), geological and hydrogeological data added to historical and recent urbanization information were compared to the permanent scatterer (PS) data from the European Remote Sensing satellites (ERS-1/2, 1992-2000) and ENVISAT (2002-2005) descending scenes, in order to produce a ground stability layer (GSL). Based on the PS data, most of the territory appears stable (almost 70 % of PS velocities are within ±1 mm/year). About 14 % of the PSs show positive line-of-sight (LOS) velocities (measured along the LOS of the satellite) between 1 and 3 mm/year and more than 2 % exceed 3 mm/year; more than 11 % of PSs show negative LOS velocities between -1 and -3 mm/year, while about 3 % exceed -3 mm/year (with tens of the PSs showing velocities over -20 mm/year). The GSL is comprised of polygons or multi-polygons (multipart polygons grouping individual polygons under a single identifier geohazard) enclosing areas where geohazards have been pointed out by PS data and/or in situ surveys (observed instabilities), and by polygons enclosing areas potentially affected by geohazards, based on the available knowledge of the territory (potential instabilities). In Roma's GSL, 18 multi-polygons (covering ca. 600 km2) related to observed instabilities have been outlined, where ground movements could be detected through InSAR data or where landslides and sinkholes are known to have occurred. Other 13 multi-polygons (covering nearly 900 km2) concern areas where the potential occurrence

  15. Deformation Mapping for Coal Mining Using Time-Series InSAR Combining Persistent Scatterer and Distributed Scatterer in Huainan City, China (United States)

    Zhang, Zhengjia; Tang, Yixian; Wang, Chao; Zhang, Hong


    A modified time-series InSAR technique combing Persistent Scatterers and Distributed scatterers is applied to obtain the deformation information at coal mining areas in Huainan city. In order to select DSs, a selecting strategy combining both classified information and statistical characteristics is used. To control error propagation and improve computational efficiency, a region growing-based strategy is applied to extract the deformation rate at DSs. A series of Radarsat-2 HH polarization images collected in Huainan over a period of approximately two years are processed to verify the effectiveness of the proposed method. The experimental results show that zones with obvious subsidence are detected in coal mining areas with a maximum deformation rate larger than 10.7 cm/year during the observation period.

  16. A reassessment of earthquake depths in the Zagros with observations from InSAR and local seismic data (United States)

    Nissen, Edwin; Jackson, James; Tatar, Mohammad; Yamini-Fard, Farzam


    The Zagros mountains of Iran are one of the most seismically active fold-and-thrust belts in the world, with frequent reverse faulting earthquakes of Mw 5 - 6 and rare larger events of up to Mw ~6.7. Earthquakes in the Zagros rarely rupture the surface, and there is a long-standing debate over whether faulting is restricted to the basement or also occurs within the thick (~10 km) sedimentary cover. In addition, there is little consensus on whether the buried reverse faults control the growth of ‘whaleback' anticlines that dominate the topography of the range, or whether faulting and folding are detached along weak layers in the sedimentary cover. To address these problems we investigated some recent earthquakes in the south-eastern Zagros, at Qeshm Island (27 November 2005 and 10 September 2008) and Fin (25 March 2006). We used radar interferometry (InSAR) to map coseismic ground displacements for each earthquake, and modelled these data using elastic dislocation theory to determine the source parameters, including the geometry and the top and bottom depths of the causative faulting. In each case, we found rupture was concentrated between a bottom depth of 8 - 10 km and a top depth of 3 - 5 km. These results confirm that Mw ~6 earthquakes do occur within the folded sediments, probably within the thick ‘competent group' of Paleozoic and Mesozoic conglomerates and platform carbonates that make up the lower part of the cover. Furthermore, patterns of coseismic uplift showed little correlation with the location of surface anticlines, implying that locally the two are decoupled. We also measured the distribution of smaller aftershocks using data from local seismic networks. Most of these occurred within the crystalline basement, at depths of ~10 km to ~20 km, substantially and resolvably deeper than the main-shock faulting. This vertical separation indicates that the main earthquakes failed to rupture the full thickness of the seismogenic layer, and probably

  17. Surface motion of active rock glaciers in the Sierra Nevada, California, USA: inventory and a case study using InSAR

    Directory of Open Access Journals (Sweden)

    Lin Liu


    Full Text Available Despite the abundance of rock glaciers in the Sierra Nevada of California, USA, few efforts have been made to measure their surface flow. Here we use the interferometric synthetic aperture radar (InSAR technique to compile a~benchmark inventory describing the kinematic state of 59 active rock glaciers in this region. Statistically, these rock glaciers moved at speeds range from 15 cm yr−1 to 88 cm yr−1 with a mean value of 55 cm yr−1 in the late summer of 2007. We also find a spatial gradient: rock glaciers in the southern Sierra Nevada moved faster than the ones in the central Sierra Nevada. In addition to the inventory mapping, we also conduct a case study to measure the surface flow of the Mount Gibbs rock glacier in fine spatial and temporal detail. The InSAR measurements over this target reveal (1 that the spatial pattern of surface flow is influenced by surface geomorphological features and (2 a significant seasonal variation of flow speed whose peak value was 48 cm yr−1 in the fall, more than twice the minimum value observed in the spring. The seasonal variation lagged air temperatures by three months and likely results from temporal changes in mechanical strength of mixing debris and ice, internal melting of ice, and surface snow cover. Our finding on the seasonal variation of surface speed reinforces the importance of a long time series with high temporal sampling rates to detect possible long-term changes of rock glaciers in a warming climate.

  18. Surface motion of active rock glaciers in the Sierra Nevada, California, USA: inventory and a case study using InSAR (United States)

    Liu, Lin; Millar, C. I.; Westfall, R. D.; Zebker, H. A.


    Despite the abundance of rock glaciers in the Sierra Nevada of California, USA, few efforts have been made to measure their surface flow. Here we use the interferometric synthetic aperture radar (InSAR) technique to compile a~benchmark inventory describing the kinematic state of 59 active rock glaciers in this region. Statistically, these rock glaciers moved at speeds range from 15 cm yr-1 to 88 cm yr-1 with a mean value of 55 cm yr-1 in the late summer of 2007. We also find a spatial gradient: rock glaciers in the southern Sierra Nevada moved faster than the ones in the central Sierra Nevada. In addition to the inventory mapping, we also conduct a case study to measure the surface flow of the Mount Gibbs rock glacier in fine spatial and temporal detail. The InSAR measurements over this target reveal (1) that the spatial pattern of surface flow is influenced by surface geomorphological features and (2) a significant seasonal variation of flow speed whose peak value was 48 cm yr-1 in the fall, more than twice the minimum value observed in the spring. The seasonal variation lagged air temperatures by three months and likely results from temporal changes in mechanical strength of mixing debris and ice, internal melting of ice, and surface snow cover. Our finding on the seasonal variation of surface speed reinforces the importance of a long time series with high temporal sampling rates to detect possible long-term changes of rock glaciers in a warming climate.

  19. Recent land subsidence caused by the rapid urban development in the Hanoi urban region (Vietnam using ALOS InSAR data

    Directory of Open Access Journals (Sweden)

    V. K. Dang


    Full Text Available Since the 1990s the land subsidence due to the rapid urbanization has been considered a severely destructive hazard in the center of Hanoi City. Although previous studies and measurements have quantified the subsiding deformation in Hanoi center, no data exist for the newly established districts in the south and the west, where construction development has been most significant and where groundwater pumping has been very intensive over the last decade. With a multi-temporal InSAR approach, we quantify the spatial distribution of the land subsidence in the whole Hanoi urban region using ALOS images over the 2007–2011 period. The map of the mean subsidence velocity reveals that the northern bank of the Red River appears stable, whereas some areas in southern bank are subsiding with a mean vertical rate up to 68 mm yr−1, especially within the three new urban districts of Hoang Mai, Ha Dong and Hoai Duc. We interpret the spatial distribution of the surface deformation as the combination of the nature of the unsaturated layer, the lowering of groundwater in the aquifers due to pumping withdrawal capacity, the increase of built-up surfaces and the type of building foundation. The time evolution deduced from the InSAR time series is consistent with previous leveling data and shows that the lowering rate of the surface slightly decreases till 2008. Then, a seasonal variation suggests that the deformation became non-stationary, with upward and downward transient displacements related to the charge and discharge of the aquifer following the changes between rainy and dry seasons.

  20. Long-term and seasonal ground deformation in the Santa Clara Valley, California, revealed by multi decadal InSAR time series (United States)

    Chaussard, E.; Burgmann, R.; Shirzaei, M.; Baker, B.


    The Santa Clara Valley, California, is a shallow basin located between the San Andreas and Hayward-Calaveras fault zones. The Valley is known to experience land subsidence and uplift related to groundwater extraction and recharge. We use Small Baseline (SB) Interferometric Synthetic Aperture Radar (InSAR) time series to precisely map time-dependent ground deformation at the scale of the basin, relying on data sets from 4 satellites (ERS1, ERS2, Envisat, and ALOS1) to cover a twenty-year time period (1992-2012). The ground deformation map produced provides constraints on the lateral distribution of water-bearing units in the valley, information that is critical to effectively manage groundwater resources, and on the areas more likely to experience subsidence related ground deformation or flooding. Multi-year and seasonal time-series reveal different ground deformation patterns. Long-term uplift at few millimeters per year dominates east of the Silver Creek fault (SCF) and likely relates to the poroelastic response of the confined aquifer to recovery of groundwater levels since the 1960s. In contrast seasonal uplift and subsidence in winter and summer, respectively, dominate west of the SCF, near San Jose. We compare the InSAR derived deformation to precipitation and well data to explain this seasonal variability. The differential subsidence across the SCF indicates that the fault partitions the shallow confined aquifer and was likely active since the deposition of these Holocene sediments. Relying on the multiple viewing geometries from the different spacecraft we isolate a narrow band of horizontal deformation in the immediate vicinity of the SCF. This zone of high extensional strain is due to the localized differential subsidence and is likely to experience fissuring.

  1. Coseismic and early postseismic slip of the 2014 South Napa earthquake from ABIC-based modeling of campaign GPS and InSAR data (United States)

    Funning, G.; Floyd, M.; Swiatlowski, J.; Herring, T.; Murray, J. R.; Svarc, J. L.; Johanson, I. A.; Yun, S. H.


    The August 24, 2014 South Napa, CA earthquake caused extensive surface rupture of a ~15 km zone along the western edge of Napa valley, including portions of the previously mapped West Napa fault. In the days following the event, growing offsets in cultural features crossing the main rupture strand indicated the occurrence of significant shallow afterslip. Here we use near-field campaign GPS data and InSAR data that closely bracket the earthquake and its early postseismic period to constrain models of the slip on that fault during and after the event. A joint inverse modeling approach based upon Akaike's Bayesian Information Criterion (ABIC) is used to optimally weight the contributions of each dataset and the smoothing constraint that we apply. Our model inputs are: (i) a GPS dataset, comprising pre-event data collected in campaign mode six weeks before the mainshock and three weeks of post-event data starting 8-36 hours after the mainshock collected in semi-continuous mode, from sites at distances 2-20 km from the rupture; and (ii) quadtree-downsampled InSAR data from both descending and ascending passes of the COSMO-SkyMed satellite constellation (first post-event acquisitions made 3 and 10 days after the mainshock, respectively). The former provide strong control on the timing of fault slip, the latter provide strong spatial constraints on fault location and geometry. Preliminary results indicate that the majority of coseismic slip occurred on a NNW-striking subvertical fault plane whose location is consistent with the mapped main surface rupture strand. The pattern of slip shallows significantly from the hypocenter along-strike to the NNW, peaking at ~1 m of slip at depths of 2-4 km, ~8 km NNW of the hypocenter.

  2. Shifts in the eruptive styles at Stromboli in 2010–2014 revealed by ground-based InSAR data (United States)

    Di Traglia, Federico; Battaglia, Maurizio; Nolesini, Teresa; Lagomarsino, Daniela; Casaglia, Nicola


    Ground-Based Interferometric Synthetic Aperture Radar (GBInSAR) is an efficient technique for capturing short, subtle episodes of conduit pressurization in open vent volcanoes like Stromboli (Italy), because it can detect very shallow magma storage, which is difficult to identify using other methods. This technique allows the user to choose the optimal radar location for measuring the most significant deformation signal, provides an exceptional geometrical resolution, and allows for continuous monitoring of the deformation. Here, we present and model ground displacements collected at Stromboli by GBInSAR from January 2010 to August 2014. During this period, the volcano experienced several episodes of intense volcanic activity, culminated in the effusive flank eruption of August 2014. Modelling of the deformation allowed us to estimate a source depth of 482 ± 46 m a.s.l. The cumulative volume change was 4.7 ± 2.6 × 105 m3. The strain energy of the source was evaluated 3–5 times higher than the surface energy needed to open the 6–7 August eruptive fissure. The analysis proposed here can help forecast shifts in the eruptive style and especially the onset of flank eruptions at Stromboli and at similar volcanic systems (e.g. Etna, Piton de La Fournaise, Kilauea).

  3. Towards Insar Everywhere, all the Time, with SENTINEL-1 (United States)

    Li, Zhenhong; Wright, Tim; Hooper, Andrew; Crippa, Paola; Gonzalez, Pablo; Walters, Richard; Elliott, John; Ebmeier, Susanna; Hatton, Emma; Parsons, Barry


    Sentinel-1A was launched in April 2014, and has been collecting data routinely over more than one year. Sentinel-1B is set for launch on 22 April 2016. The Sentinel-1 constellation has several advantages over previous radar missions for InSAR applications: (1) Data are being acquired systematically for tectonic and volcanic areas, (2) Images cover a wide footprint, 250 km from near to far range in Interferometric Wide Swath (TOPS) mode, (3) Small perpendicular and temporal baselines greatly improve interferometric coherence at C-band, (4) Data are freely available to all users, (5) The mission is planned to be operational for 20 years, with 1C and 1D planned for future launches. These features enable us to map geological processes occurring in any place at anytime using InSAR. We will review progress within COMET towards our ultimate goal of building a fully-automated processing system that provides deformation results and derived products to the wide InSAR and Geophysics communities. In addition to high-resolution-ECMWFbased atmospheric correction model, we will show results of a systematic analysis of interferometric coherence in tectonic and volcanic areas, and discuss the future goals and timeline for the COMET InSAR automated processing system.

  4. Tectonic, volcanic and human activity ground deformation signals detected by multitemporal InSAR techniques in the Colima Volcanic Complex (Mexico) rift (United States)

    Brunori, C.; Norini, G.; Bignami, C.; Groppelli, G.; Zucca, F.; Stramondo, S.; Capra, L.; Cabral-Cano, E.


    The evolution of volcanoes is strictly related with their substratum and the regional tectonics. The link among morphology, geology and structure of volcanic edifices and the geological-structural characteristics of the basement is important to understand hazardous phenomena as flank eruptions and lateral collapses of volcanoes. The Colima Rift is an active regional structure, N-S oriented and more than 100 km long and 10 wide. This rift is filled by a ~1 km-thick sequence of quaternary lacustrine sediments, alluvium, and colluvium, mostly underling the about 3000 m thick volcanic pile of the Colima Volcanic Complex (CVC). In addition to the regional structures curved faults, roughly E-W oriented, are observed on the CVC edifice due to the spreading of the volcano moving southward on the weak basement. So in the CVC edifice and surrounding area we can observe the interaction of regional structures and volcanic ones due to the gravitational loading of the volcanic edifice on the weak substratum of the graben. To measure displacements due to magma movement at depth and interaction of regional structures and volcanic ones, SAR interferometry has proven to be a reliable method; however, andesitic stratovolcanoes like the CVC indeed,remain difficult to survey using this technique. The main causes are their specific geometry (steep topography), which induces strong tropospheric artefacts, environmental conditions (e.g., mainly vegetation, ash and/or snow cover), leading to a loss of coherency. In this work we try to detect deformations phenomena for the wide CVC using a robust multitemporal InSAR approach Differential Synthetic Aperture Radar Interferometry (DInSAR). We apply the Hooper (2008) DInSAR algorithm (StamPS/MTI) both to ENVISAT ASARr images acquired from 1993 to 2007 and to ALOS PALSAR (datasets from 2006 to 2010) in order to determine the deformation patterns in the CVC.

  5. 一种基于DSP+FPGA架构的InSAR实时信号处理平台设计%Design of InSAR Real-time Signal Processing Platform Based on DSP+FPGA

    Institute of Scientific and Technical Information of China (English)

    王光; 索志勇


    本文设计了一款高性能多核InSAR实时信号处理平台,包括雷达回波数据采集、InSAR 实时信号处理和1553B 总线通信.该设计采用TI 公司的最新一代多核DSP 旗舰产品TMS320C6678以及ALTERA公司的Stratix IV GX系列FPGA芯片EP4SGX230,构建了基于DSP + FPGA架构的InSAR实时信号处理平台.经仿真验证,该InSAR实时信号处理平台的运算性能和数据传输能力能够满足InSAR实时处理的要求.%A multi-core InSAR real-time signal processing platform with high performance is developed, which realizes the data acquisition of radar echo, InSAR real-time processing and 1553B bus communication. The radar signal processing platform is based on DSP+FPGA architecture, with the TI's latest high performance multi-core DSP processor TMS320C6678 and ALTERA's Stratix Ⅳ GX series FPGA chip EP4SGX230. It is proved that the processing performance and data transmission capabilities of the real-time signal processing platform InSAR can fully meet the requirements of real-time processing InSAR.

  6. Characterization of Ground Deformation above AN Urban Tunnel by Means of Insar Time Series Analysis (United States)

    Ferretti, A.; Iannacone, J.; Falorni, G.; Berti, M.; Corsini, A.


    Ground deformation produced by tunnel excavation in urban areas can cause damage to buildings and infrastructure. In these contexts, monitoring systems are required to determine the surface area affected by displacement and the rates of movement. Advanced multi-image satellite-based InSAR approaches are uniquely suited for this purpose as they provide an overview of the entire affected area and can measure movement rates with millimeter precision. Persistent scatterer approaches such as SqueeSAR™ use reflections off buildings, lampposts, roads, etc to produce a high-density point cloud in which each point has a time series of deformation spanning the period covered by the imagery. We investigated an area of about 10 km2 in North Vancouver, (Canada) where the shaft excavation of the Seymour-Capilano water filtration plant was started in 2004. As part of the project, twin tunnels in bedrock were excavated to transfer water from the Capilano Reservoir to the treatment plant. A radar dataset comprising 58 images (spanning March 2001 - June 2008) acquired by the Radarsat-1 satellite and covering the period of excavation was processed with the SqueeSAR™ algorithm (Ferretti et al., 2011) to assess the ground deformation caused by the tunnel excavation. To better characterize the deformation in the time and space domains and correlate ground movement with excavation, an in-depth time series analysis was carried out. Berti et al. (2013) developed an automatic procedure for the analysis of InSAR time series based on a sequence of statistical tests. The tool classifies time series into six distinctive types (uncorrelated; linear; quadratic; bilinear; discontinuous without constant velocity; discontinuous with change in velocity) which can be linked to different physical phenomena. It also provides a series of descriptive parameters which can be used to characterize the temporal changes of ground motion. We processed the movement time series with PSTime to determine the

  7. Deformation history of Mauna Loa (Hawaii) from 2003 to 2014 through InSAR data: understanding the shorter-term processes (United States)

    La Marra, Daniele; Poland, Michael P.; Acocella, Valerio; Battaglia, Maurizio; Miklius, Asta


    Geodesy allows detecting the deformation of volcanoes, thus understanding magmatic processes. This becomes particularly efficient when time series are available and volcanoes can be monitored on the mean-term (decades), and not only during a specific event. Here we exploit the SBAS technique, using SAR images from ENVISAT (descending and ascending orbits; 2003 - 2010) and COSMO-SkyMed (descending and ascending orbits; 2012 - 2014), to study a decade of deformation at Mauna Loa (Hawaii). These data are merged time series data from 24 continuously operating GPS stations, which allows us to calibrate the InSAR time series. Our results show a long-term inflation of the volcano from 2003 to 2014, reaching a peak of ~11 cm/yr on the summit area between mid-2004 to mid-2005 and then slowing down. Within this frame, we were able to identify five main periods with approximately linear deformation behavior. The inversion of the deformation data in the first four periods suggests the repeated, though not constant, intrusion of one or more dikes below the summit caldera and the upper Southwest Rift Zone. Moreover, the dike intrusion coincides with minor acceleration of flank slip. Such a behavior is distinctive and, with the exception of the nearby Kilauea, has not been observed at any other volcano on the mean term. It is proposed that continuous, even though not constant flank instability of the SE flank may promote semi-continuous intrusions in a volcano with a ready magma supply.

  8. Tropospheric delay correction to InSAR results using CGPS observations%基于CGPS数据的InSAR对流层延迟改正研究

    Institute of Scientific and Technical Information of China (English)

    周金国; 崔书珍; 彭军还


    利用CGPS数据和站间、历元间的双差模型来计算InSAR大气延迟改正量.通过新西兰GEONET站网CGPS数据,研究了多雨山区的InSAR对流层延迟内插模型及对流层延迟参数估计个数问题,实验表明IDW和Kriging内插模型都能较好的适用于多雨山区的InSAR对流层延迟改正量内插,每隔5分钟估计一个对流层参数是比较合理的.%InSAR atmospheric delay correction is calculated using CGPS data and between-site and between-epoch double difference model. Which interpolation model is most suitable to InSAR tropospheric delay correction and how many troposphere parameters should be determined is analyzed for rainy mountainous area with New Zealand's GEONET CGPS data. It is suggested that either the IDW or the Kriging interpolation method be used to determine tropospheric delay parameters from GPS observations for rainy mountain areas. And estimating tropospheric delay parameters for 5-minute time intervals is reasonable.

  9. Geodetic model of the 2015 April 25 Mw 7.8 Gorkha Nepal Earthquake and Mw 7.3 aftershock estimated from InSAR and GPS data (United States)

    Feng, Guangcai; Li, Zhiwei; Shan, Xinjian; Zhang, Lei; Zhang, Guohong; Zhu, Jianjun


    We map the complete surface deformation of 2015 Mw 7.8 Gorkha Nepal earthquake and its Mw 7.3 aftershock with two parallel ALOS2 descending ScanSAR paths' and two ascending Stripmap paths' images. The coseismic fault-slip model from a combined inversion of InSAR and GPS data reveals that this event is a reverse fault motion, with a slight right-lateral strike-slip component. The maximum thrust-slip and right-lateral strike-slip values are 5.7 and 1.2 m, respectively, located at a depth of 7-15 km, southeast to the epicentre. The total seismic moment 7.55 × 1020 Nm, corresponding to a moment magnitude Mw 7.89, is similar to the seismological estimates. Fault slips of both the main shock and the largest aftershock are absent from the upper thrust shallower than 7 km, indicating that there is a locking lower edge of Himalayan Main Frontal Thrust and future seismic disaster is not unexpected in this area. We also find that the energy released in this earthquake is much less than the accumulated moment deficit over the past seven centuries estimated in previous studies, so the region surrounding Kathmandu is still under the threaten of seismic hazards.

  10. Ground subsidence and associated ground fracturing in urban areas: InSAR monitoring of active tectonic structures (Ciudad Guzman, Colima Graben - Mexico) (United States)

    Bignami, C.; Brunori, C.; Zucca, F.; Groppelli, G.; Norini, G.; Hernandez, N. D.; Stramondo, S.


    This study focuses on the observation of a creeping phenomenon that produces subsidence of the Zapotlan basin and ground fracturing in correspondence of the Ciudad Guzmàn (Jalisco - Mexico). The September 21, 2012, the Ciudad Guzmàn has been struck by a phenomenon of ground fracturing of about 1.5 km of length. This event caused the deformation of the roads and the damage of 30 houses, of which eight have been declared uninhabitable. The alignment of fractures is coincident with the escarpments produced in September 19, 1985, in the Ciudad Guzman urban area, when a strong earthquake, magnitude 8.1, struck the Mexican area, causing the deaths of at least 10,000 people and serious damage in Mexico City. In Ciudad Guzmán, about 60% of the buildings were destroyed, with about 50 loss of life. The city is located in the Zapotlan basin (northern Colima graben), a wide tectonic depression where the depth of the infilling sediments is about 1 km. This subsidence cannot be measured outside the urbanized area, but it can be considered as a deformation mechanism of the central part of the basin. In order to detect and mapping the spatio-temporal features of the processes that led to this event, we applied InSAR multi-temporal techniques to analyze a dataset of ENVISAT satellite SAR images, acquired in a time span between 2003-2010. InSAR techniques detect a subsidence of the north-western part of Ciudad Guzmàn of about 15 mm/yr in the time interval 2003-2010. The displacement occurred in September 21, 2012, was detected using two RadarSAT2 acquisitions (2012-03-22 and 2013-03-17). The explanation of surface movements based on interferometric results, ground data and geological field observations, allowed confirming surface effect due to the overexploitation of the aquifers and highlights a subsidence due to anthropogenic causes coupled to buried tectonic structures.

  11. A Methodology to Validate the InSAR Derived Displacement Field of the September 7th, 1999 Athens Earthquake Using Terrestrial Surveying. Improvement of the Assessed Deformation Field by Interferometric Stacking (United States)

    Kotsis, Ioannis; Kontoes, Charalabos; Paradissis, Dimitrios; Karamitsos, Spyros; Elias, Panagiotis; Papoutsis, Ioannis


    The primary objective of this paper is the evaluation of the InSAR derived displacement field caused by the 07/09/1999 Athens earthquake, using as reference an external data source provided by terrestrial surveying along the Mornos river open aqueduct. To accomplish this, a processing chain to render comparable the leveling measurements and the interferometric derived measurements has been developed. The distinct steps proposed include a solution for reducing the orbital and atmospheric interferometric fringes and an innovative method to compute the actual InSAR estimated vertical ground subsidence, for direct comparison with the leveling data. Results indicate that the modeled deformation derived from a series of stacked interferograms, falls entirely within the confidence interval assessed for the terrestrial surveying data. PMID:27879926

  12. A Methodology to Validate the InSAR Derived Displacement Field of the September 7th, 1999 Athens Earthquake Using Terrestrial Surveying. Improvement of the Assessed Deformation Field by Interferometric Stacking

    Directory of Open Access Journals (Sweden)

    Ioannis Papoutsis


    Full Text Available The primary objective of this paper is the evaluation of the InSAR derived displacement field caused by the 07/09/1999 Athens earthquake, using as reference an external data source provided by terrestrial surveying along the Mornos river open aqueduct. To accomplish this, a processing chain to render comparable the leveling measurements and the interferometric derived measurements has been developed. The distinct steps proposed include a solution for reducing the orbital and atmospheric interferometric fringes and an innovative method to compute the actual InSAR estimated vertical ground subsidence, for direct comparison with the leveling data. Results indicate that the modeled deformation derived from a series of stacked interferograms, falls entirely within the confidence interval assessed for the terrestrial surveying data.

  13. A Methodology to Validate the InSAR Derived Displacement Field of the September 7th, 1999 Athens Earthquake Using Terrestrial Surveying. Improvement of the Assessed Deformation Field by Interferometric Stacking


    Ioannis Papoutsis; Panagiotis Elias; Spyros Karamitsos; Dimitrios Paradissis; Charalabos Kontoes; Ioannis Kotsis


    The primary objective of this paper is the evaluation of the InSAR derived displacement field caused by the 07/09/1999 Athens earthquake, using as reference an external data source provided by terrestrial surveying along the Mornos river open aqueduct. To accomplish this, a processing chain to render comparable the leveling measurements and the interferometric derived measurements has been developed. The distinct steps proposed include a solution for reducing the orbital and atmospheric inter...

  14. The Penetration Depth Derived from the Synthesis of ALOS/PALSAR InSAR Data and ASTER GDEM for the Mapping of Forest Biomass

    Directory of Open Access Journals (Sweden)

    Wenjian Ni


    Full Text Available The Global Digital Elevation Model produced from stereo images of Advanced Spaceborne Thermal Emission and Reflection Radiometer data (ASTER GDEM covers land surfaces between latitudes of 83°N and 83°S. The Phased Array type L-band Synthetic Aperture Radar (PALSAR onboard Advanced Land Observing Satellite (ALOS collected many SAR images since it was launched on 24 January 2006. The combination of ALOS/PALSAR interferometric data and ASTER GDEM should provide the penetration depth of SAR data assuming ASTER GDEM was the elevation of vegetation canopy top. It would be correlated with forest biomass because penetration depth could be affected by forest density and forest canopy height. Their combination held great promises for the forest biomass mapping over large area. The feasibility of forest biomass mapping through the data synthesis of ALOS/PALSAR InSAR data and ASTER GDEM was investigated in this study. A procedure for the extraction of penetration depth was firstly proposed. Then three models were built for biomass estimation: (I model only using backscattering coefficients of ALOS/PALSAR data; (II model only using penetration depth; (III model using both of them. The biomass estimated from Lidar data was taken as reference data to evaluate the three different models. The results showed that the combination of backscattering coefficients and penetration depth gave the best accuracy. The forest disturbance has to be considered in forest biomass estimation because of the long time span of ASTER data for generating ASTER GDEM. The spatial homogeneity could be used to improve estimation accuracy.

  15. Landslide kinematics and their potential controls from hourly to decadal timescales: Insights from integrating ground-based InSAR measurements with structural maps and long-term monitoring data (United States)

    Schulz, William H.; Coe, Jeffrey A.; Ricci, Pier P.; Smoczyk, Gregory M.; Shurtleff, Brett L.; Panosky, Joanna


    Knowledge of kinematics is rudimentary for understanding landslide controls and is increasingly valuable with greater spatiotemporal coverage. However, characterizing landslide-wide kinematics is rare, especially at broadly ranging timescales. We used highly detailed kinematic data obtained using photogrammetry and field mapping during the 1980s and 1990s and our 4.3-day ground-based InSAR survey during 2010 to study kinematics of the large, persistently moving Slumgullion landslide. The landslide was segregated into 11 kinematic elements using the 1980s-1990s data and the InSAR survey revealed most of these elements within a few hours. Averages of InSAR-derived displacement point measures within each element agreed well with higher quality in situ observations; averaging was deemed necessary because adverse look angles for the radar coupled with tree cover on the landslide introduced error in the InSAR results. We found that the landslide moved during 2010 at about half its 1985-1990 speed, but slowing was most pronounced at the landslide head. Gradually decreased precipitation and increased temperature between the periods likely resulted in lower groundwater levels and consequent slowing of the landslide. We used GPS survey results and limit-equilibrium modeling to analyze changing stability of the landslide head from observed thinning and found that its stability increased between the two periods, which would result in its slowing, and the consequent slowing of the entire landslide. Additionally, InSAR results suggested movement of kinematic element boundaries in the head region and our field mapping verified that they moved and changed character, likely because of the long-term increasing head stability. On an hourly basis, InSAR results were near error bounds but suggested landslide acceleration in response to seemingly negligible rainfall. Pore-pressure diffusion modeling suggested that rainfall infiltration affected frictional strength only to shallow depths

  16. Landslide kinematics and their potential controls from hourly to decadal timescales: Insights from integrating ground-based InSAR measurements with structural maps and long-term monitoring data (United States)

    Schulz, William; Coe, Jeffrey A.; Ricci, P.P; Smoczyk, Gregory M.; Shurtleff, Brett L; Panosky, J


    Knowledge of kinematics is rudimentary for understanding landslide controls and is increasingly valuable with greater spatiotemporal coverage. However, characterizing landslide-wide kinematics is rare, especially at broadly ranging timescales. We used highly detailed kinematic data obtained using photogrammetry and field mapping during the 1980s and 1990s and our 4.3-day ground-based InSAR survey during 2010 to study kinematics of the large, persistently moving Slumgullion landslide. The landslide was segregated into 11 kinematic elements using the 1980s–1990s data and the InSAR survey revealed most of these elements within a few hours. Averages of InSAR-derived displacement point measures within each element agreed well with higher quality in situ observations; averaging was deemed necessary because adverse look angles for the radar coupled with tree cover on the landslide introduced error in the InSAR results. We found that the landslide moved during 2010 at about half its 1985–1990 speed, but slowing was most pronounced at the landslide head. Gradually decreased precipitation and increased temperature between the periods likely resulted in lower groundwater levels and consequent slowing of the landslide. We used GPS survey results and limit-equilibrium modeling to analyze changing stability of the landslide head from observed thinning and found that its stability increased between the two periods, which would result in its slowing, and the consequent slowing of the entire landslide. Additionally, InSAR results suggested movement of kinematic element boundaries in the head region and our field mapping verified that they moved and changed character, likely because of the long-term increasing head stability. On an hourly basis, InSAR results were near error bounds but suggested landslide acceleration in response to seemingly negligible rainfall. Pore-pressure diffusion modeling suggested that rainfall infiltration affected frictional strength only to shallow

  17. Monitoring dam structural health from space: Insights from novel InSAR techniques and multi-parametric modeling applied to the Pertusillo dam Basilicata, Italy (United States)

    Milillo, Pietro; Perissin, Daniele; Salzer, Jacqueline T.; Lundgren, Paul; Lacava, Giusy; Milillo, Giovanni; Serio, Carmine


    The availability of new constellations of synthetic aperture radar (SAR) sensors is leading to important advances in infrastructure monitoring. These constellations offer the advantage of reduced revisit times, providing low-latency data that enable analysis that can identify infrastructure instability and dynamic deformation processes. In this paper we use COSMO-SkyMed (CSK) and TerraSAR-X (TSX) data to monitor seasonal induced deformation at the Pertusillo dam (Basilicata, Italy) using multi-temporal SAR data analysis. We analyzed 198 images spanning 2010-2015 using a coherent and incoherent PS approach to merge COSMO-SkyMed adjacent tracks and TerraSAR-X acquisitions, respectively. We used hydrostatic-seasonal-temporal (HST) and hydrostatic-temperature-temporal (HTT) models to interpret the non-linear deformation at the dam wall using ground measurements together with SAR time-series analysis. Different look geometries allowed us to characterize the horizontal deformation field typically observed at dams. Within the limits of our models and the SAR acquisition sampling we found that most of the deformation at the Pertusillo dam can be explained by taking into account only thermal seasonal dilation and hydrostatic pressure. The different models show slightly different results when interpreting the aging term at the dam wall. The results highlight how short-revisit SAR satellites in combination with models widely used in the literature for interpreting pendulum and GPS data can be used for supporting structural health monitoring and provide valuable information to ground users directly involved in field measurements.

  18. Deformation Monitoring of Highway Goaf Based on D - InSAR Technology%基于D—InSAR技术的公路采空区变形监测

    Institute of Scientific and Technical Information of China (English)

    刘晓菲; 邓喀中; 薛继群; 陈炳乾; 王江涛


    This paper uses the ALOS satellite 6 scene PALSAR as experimental data. Using the mathematical model processed by two - track differential interferometric, after completing image registration, resample, removing terrain phase, filtering and phase unwrap- ping, the D - InSAR strip deformation time series of highway goaf are achieved. Comparing the test data with measured data and cor- recting InSAR data, the results show that it is feasible to use the D- InSAR to monitoring highway deformation above goaf, which has broad application prospects.%利用某高速采空区的ALOS卫星6景PALSAR数据,采用二轨差分干涉处理的数学模型,在完成图像的配准、重采样、去除地形相位、滤波和相位解缠之后,获取了高速公路采空区D—InSAR条带变形时间序列,并与实测数据进行了比较,将InSAR数据进行改正,结果显示D—InSAR用于公路采空区变形监测是可行的,具有广泛的应用前景。

  19. Multiresolution analysis of SAR data (United States)

    Hummel, Robert


    The 'Multiresolution Analysis of SAR Data' program supported research work in five areas. Geometric hashing theory can now be viewed as a Bayesian approach to object recognition. False alarm rates can be greatly reduced by using certain enhancements and modifications developed under this project. Geometric hashing algorithms now exist for the Connection Machine. Recognition of synthetically-produced dot arrays was demonstrated using a model base of 1024 objects. The work represents a substantial advance over existing model-based vision capabilities. Algorithms were developed for determining the translation and rotation of a sensor given only the image flow field data. These are new algorithms, and are much more stable than existing computer vision algorithms for this task. The algorithms might provide independent verification of gyroscopic data, or might be used to compute relative motion with respect to a moving scene object, or may be useful for motion-based segmentation. Our theories explaining the Dempster/Shafer calculus and developing new uncertainty reasoning calculi were extended, and presented at a conference and were incorporated into the Bayesian interpretation of geometric hashing. 'Wavelet Slice Theorem' was developed in several different versions, any of which yields an alternate approach to image formation. The result may well provide a more stable approach to image formation than the standard Fourier-based projection slide theorem, since interpolation of unknown spectra values is better-founded.

  20. A Hierarchical Multi-Temporal InSAR Method for Increasing the Spatial Density of Deformation Measurements

    Directory of Open Access Journals (Sweden)

    Tao Li


    Full Text Available Point-like targets are useful in providing surface deformation with the time series of synthetic aperture radar (SAR images using the multi-temporal interferometric synthetic aperture radar (MTInSAR methodology. However, the spatial density of point-like targets is low, especially in non-urban areas. In this paper, a hierarchical MTInSAR method is proposed to increase the spatial density of deformation measurements by tracking both the point-like targets and the distributed targets with the temporal steadiness of radar backscattering. To efficiently reduce error propagation, the deformation rates on point-like targets with lower amplitude dispersion index values are first estimated using a least squared estimator and a region growing method. Afterwards, the distributed targets are identified using the amplitude dispersion index and a Pearson correlation coefficient through a multi-level processing strategy. Meanwhile, the deformation rates on distributed targets are estimated during the multi-level processing. The proposed MTInSAR method has been tested for subsidence detection over a suburban area located in Tianjin, China using 40 high-resolution TerraSAR-X images acquired between 2009 and 2010, and validated using the ground-based leveling measurements. The experiment results indicate that the spatial density of deformation measurements can be increased by about 250% and that subsidence accuracy can reach to the millimeter level by using the hierarchical MTInSAR method.

  1. The May 2005 eruption of Fernandina volcano, Galápagos: The first circumferential dike intrusion observed by GPS and InSAR

    KAUST Repository

    Chadwick, William W Jr


    The May 2005 eruption of Fernandina volcano, Galápagos, occurred along circumferential fissures parallel to the caldera rim and fed lava flows down the steep southwestern slope of the volcano for several weeks. This was the first circumferential dike intrusion ever observed by both InSAR and GPS measurements and thus provides an opportunity to determine the subsurface geometry of these enigmatic structures that are common on Galápagos volcanoes but are rare elsewhere. Pre- and post- eruption ground deformation between 2002 and 2006 can be modeled by the inflation of two separate magma reservoirs beneath the caldera: a shallow sill at ~1 km depth and a deeper point-source at ~5 km depth, and we infer that this system also existed at the time of the 2005 eruption. The co-eruption deformation is dominated by uplift near the 2005 eruptive fissures, superimposed on a broad subsidence centered on the caldera. Modeling of the co-eruption deformation was performed by including various combinations of planar dislocations to simulate the 2005 circumferential dike intrusion. We found that a single planar dike could not match both the InSAR and GPS data. Our best-fit model includes three planar dikes connected along hinge lines to simulate a curved concave shell that is steeply dipping (~45-60°) toward the caldera at the surface and more gently dipping (~12-14°) at depth where it connects to the horizontal sub-caldera sill. The shallow sill is underlain by the deep point source. The geometry of this modeled magmatic system is consistent with the petrology of Fernandina lavas, which suggest that circumferential eruptions tap the shallowest parts of the system, whereas radial eruptions are fed from deeper levels. The recent history of eruptions at Fernandina is also consistent with the idea that circumferential and radial intrusions are sometimes in a stress-feedback relationship and alternate in time with one another. © 2010 Springer-Verlag.

  2. Damage Proxy Map from InSAR Coherence Applied to February 2011 M6.3 Christchurch Earthquake, 2011 M9.0 Tohoku-oki Earthquake, and 2011 Kirishima Volcano Eruption (United States)

    Yun, S.; Agram, P. S.; Fielding, E. J.; Simons, M.; Webb, F.; Tanaka, A.; Lundgren, P.; Owen, S. E.; Rosen, P. A.; Hensley, S.


    Under ARIA (Advanced Rapid Imaging and Analysis) project at JPL and Caltech, we developed a prototype algorithm to detect surface property change caused by natural or man-made damage using InSAR coherence change. The algorithm was tested on building demolition and construction sites in downtown Pasadena, California. The developed algorithm performed significantly better, producing 150 % higher signal-to-noise ratio, than a standard coherence change detection method. We applied the algorithm to February 2011 M6.3 Christchurch earthquake in New Zealand, 2011 M9.0 Tohoku-oki earthquake in Japan, and 2011 Kirishima volcano eruption in Kyushu, Japan, using ALOS PALSAR data. In Christchurch area we detected three different types of damage: liquefaction, building collapse, and landslide. The detected liquefaction damage is extensive in the eastern suburbs of Christchurch, showing Bexley as one of the most significantly affected areas as was reported in the media. Some places show sharp boundaries of liquefaction damage, indicating different type of ground materials that might have been formed by the meandering Avon River in the past. Well reported damaged buildings such as Christchurch Cathedral, Canterbury TV building, Pyne Gould building, and Cathedral of the Blessed Sacrament were detected by the algorithm. A landslide in Redcliffs was also clearly detected. These detected damage sites were confirmed with Google earth images provided by GeoEye. Larger-scale damage pattern also agrees well with the ground truth damage assessment map indicated with polygonal zones of 3 different damage levels, compiled by the government of New Zealand. The damage proxy map of Sendai area in Japan shows man-made structure damage due to the tsunami caused by the M9.0 Tohoku-oki earthquake. Long temporal baseline (~2.7 years) and volume scattering caused significant decorrelation in the farmlands and bush forest along the coastline. The 2011 Kirishima volcano eruption caused a lot of ash

  3. InSAR techniques for reliable deformation estimation in volcanic areas and a first glance of Tandem-DEM accuracy - test site El Hierro Island (United States)

    Cong, X.; Eineder, M.; Fritz, T.


    The accuracy and availability of deformation measurements using InSAR techniques is limited due to decorrelation effects, atmospheric disturbances and the SAR side-looking geometry (layover and shadowing). In this talk, we present our recent research and achievements on advanced InSAR techniques in order to retrieve reliable deformation signals from active volcanoes using high resolution TerraSAR-X (TSX) images. Another highlight of this talk is the evaluation of an experimental TanDEM-X (TDX) RawDEM with a resolution of approximately 6 m in order to compensate the topographic phase. A volcanic test site which is currently highly active -El Hierro- has been selected to demonstrate the developed techniques: 1) PSI processing in volcanic areas using high resolution TSX images; 2) Mitigation of atmospheric delay distortions; 3) Fusion of multi-geometrical PSI clouds. In order to measure the deformation from 2011 to 2013 at El Hierro [1], two stacks of stripmap TSX Mission data have been acquired, one in ascending orbit and one in descending. Each stack has more than 25 scenes. More than 1.5 million PSs have been detected (SCR>3.0 dB). The stratified atmospheric delay for each acquisition has been integrated for the PSI reference network and, afterwards, interpolated and compensated for all PSs. A linear deformation model has been assumed for PSI processing. For the descending orbit stack, a relative deformation from -21.7 to 131.8 mm/y from Sep. 2011 to Jan. 2013 with respect to a reference point located on the northeast coast has been measured. On the one hand, the spatial variation of the deformation has a good agreement with the seismicity distribution [1]. On the other hand, the deformation magnitude agrees with in-situ GPS measurements [2]. In ascending orbit, the linear deformation rate varies from -22.8 to 90.9 mm/y. This different range of value is due to a scene acquired on Feb. 2010, which has been included in order to obtain the pre-seismic deformation

  4. Land subsidence monitoring and prediction in Beijing based on multi-sensor InSAR and improved Gray-Markov model (United States)

    Ke, Y.; Deng, Z.; Gong, H.; Guo, L.; Li, X.


    Land subsidence induced by excessive groundwater withdrawal has posed a severe threat to city infrastructures, buildings and water and gas pipes, and has caused considerable economic loss. With rapid population increase and the corresponding rising demand for ground water, the land deformation rate has sped up. It was reported that by the end of 2010, over 65% (4281km2) of the plain area in Beijing has suffered ground settlement of over 50mm. Timely monitoring of land subsidence is a prerequisite for understanding of spatiotemporal evolution and the mechanism of the process. Prediction of future land subsidence development assists decision making for prevention of the hazard. In this study, we combined InSAR techniques with an improved Gray-Markov model (GMM) to predict the spatiotemporal trend of ground settlement in Beijing. First, ENVISAT ASAR data from 2003 to 2010 and Radarsat-2 data from 2010 to 2014 were used to monitor land subsidence during the recent 11 years by PS-InSAR technique. Three settlement bowls were demonstrated in the study area and located in Chaoyang, Changping, and Tongzhou districts. The maximum displacement rate reached around 125mm/year and the maximum cumulative deformation reached over 1.3m. For each PS pixels, we developed an improved GMM in order to predict the deformation trend in the next three years. GMM was improved in two aspects. First, we adapted GMM model based on metabolism principle by assigning newer information with higher priority. Second, we applied k-means method to automatically partition the states in Markov chain instead of manually assigning Markov intervals. By applying the improved GMM to PS pixels over the study area, the deformation maps from 2015 to 2017 were generated and it was found that the maximum cumulative deformation will reach 1.6m by the end of 2017.

  5. Source model for the 1997 Zirkuh earthquake (MW= 7.2) in Iran derived from JERS and ERS InSAR observations

    KAUST Repository

    Sudhaus, Henriette


    We present the first detailed source model of the 1997 M7.2 Zirkuh earthquake that ruptured the entire Abiz fault in East Iran producing a 125 km long, bended and segmented fault trace. Using SAR data from the ERS and JERS-1 satellites we first determined a multisegment fault model for this predominately strike-slip earthquake by estimating fault-segment dip, slip, and rake values using an evolutionary optimization algorithm. We then inverted the InSAR data for variable slip and rake in more detail along the multisegment fault plane. We complement our optimization with importance sampling of the model parameter space to ensure that the derived optimum model has a high likelihood, to detect correlations or trade-offs between model parameters, and to image the model resolution. Our results are in an agreement with field observations showing that this predominantly strike-slip earthquake had a clear change in style of faulting along its rupture. In the north we find that thrust faulting on a westerly dipping fault is accompanied with the strike-slip that changes to thrust faulting on an eastward dipping fault plane in the south. The centre part of the fault is vertical and has almost pure dextral strike-slip. The heterogeneous fault slip distribution shows two regions of low slip near significant fault step-overs of the Abiz fault and therefore these fault complexities appear to reduce the fault slip. Furthermore, shallow fault slip is generally reduced with respect to slip at depth. This shallow slip deficit varies along the Zirkuh fault from a small deficit in the North to a much larger deficit along the central part of the fault, a variation that is possibly related to different interseismic repose times.

  6. Subsidence history of the city of Morelia, Mexico based on InSAR images processed as time series (United States)

    Jaramillo, S. H.; Suárez, G.; López-Quiroz, P.


    The city of Morelia in central Mexico sits on lacustrine and fluvio-lacustrine deposits. Subsidence due to the extraction of water from the subsoil is evidenced by the presence of differential soil compaction, causing faulting and cracking of the ground and adjacent constructions. In order to study the subsidence history of the past nine years, twenty-eight ENVISAT Synthetic Aperture Radar (SAR) images acquired between May 2003 and September 2010 were processed using ROI_PAC. All scenes are descending orbit images. The resulting interferograms were filtered using an adaptive filter and, in order to increase coherence and signal-to-noise ratio, they were unwrapped using the "branch-cut" algorithm. A subset of the resulting interferograms was selected based on the following criteria. Only interferograms with spatial baseline of less than 400 m and a temporal baseline of less than 420 days were considered. The primary objective of our work was to determine the temporal evolution of the subsidence in different parts of the city. To this end, selected pixels are inverted in an independent manner from neighbouring pixels using a time series analysis. Preliminary results suggest that the central part of the basin, near the fault known as the "Central Camionera", the subsidence is almost constant with a value of 3 to 4 cm/yr until 2008. From this date on, the subsidence rates increase to values with an average of 7 to 8 cm/yr. This increase in the subsidence rate is clearly appreciated in the appearance of two clearly visible circular patterns from 2008 to 2010. Currently, an inversion is being conducted to obtain the overall subsidence history of the basin.

  7. Post-Seismic Deformation from the 2009 Mw 6.3 Dachaidan Earthquake in the Northern Qaidam Basin Detected by Small Baseline Subset InSAR Technique

    Directory of Open Access Journals (Sweden)

    Yang Liu


    Full Text Available On 28 August 2009, one thrust-faulting Mw 6.3 earthquake struck the northern Qaidam basin, China. Due to the lack of ground observations in this remote region, this study presents high-precision and high spatio-temporal resolution post-seismic deformation series with a small baseline subset InSAR technique. At the temporal scale, this changes from fast to slow with time, with a maximum uplift up to 7.4 cm along the line of sight 334 days after the event. At the spatial scale, this is more obvious at the hanging wall than that at the footwall, and decreases from the middle to both sides at the hanging wall. We then propose a method to calculate the correlation coefficient between co-seismic and post-seismic deformation by normalizing them. The correlation coefficient is found to be 0.73, indicating a similar subsurface process occurring during both phases. The results indicate that afterslip may dominate the post-seismic deformation during 19–334 days after the event, which mainly occurs with the fault geometry and depth similar to those of the c-seismic rupturing, and partly extends to the shallower and deeper depths.

  8. Rapid reinflation following the 2011-2012 rhyodacite eruption at Cordón Caulle volcano (Southern Andes) imaged by InSAR: Evidence for magma reservoir refill (United States)

    Delgado, Francisco; Pritchard, Matthew E.; Basualto, Daniel; Lazo, Jonathan; Córdova, Loreto; Lara, Luis E.


    Cordón Caulle is a large fissural volcano that has erupted rhyodacitic magma of the same composition in its past three historical eruptions in 1921, 1960, and 2011-2012. There was significant ground deformation observed before and during the 2011-2012 eruption—here we use C and X band interferometric synthetic aperture radar (InSAR) time series results to document posteruptive uplift up to 0.8 m between March 2012 and May 2015, with line-of-sight rates up to 45 cm/yr that have been largely aseismic, along with subsidence in the 2011-2012 lava flow. The 2012 uplift rate is one of the largest for silicic systems and was likely produced by the intrusion of ~0.125 km3 of magma in the same tectonically controlled plumbing system that has been active during the historical eruptions. Nevertheless, the uplift ended before the reservoir refilled with the erupted volume, maybe due to a change in the pressure gradient produced by the 2011-2012 eruption.

  9. GPS and InSAR observations of ground deformation in the northern Malawi (Nyasa) rift from the SEGMeNT project (United States)

    Durkin, W. J., IV; Pritchard, M. E.; Elliott, J.; Zheng, W.; Saria, E.; Ntambila, D.; Chindandali, P. R. N.; Nooner, S. L.; Henderson, S. T.


    We describe new ground deformation observations from the SEGMeNT (Study of Extension and maGmatism in Malawi aNd Tanzania) spanning the northern sector of the Malawi (Nyasa) rift, which is one of the few places in the world suitable for a comprehensive study of early rifting processes. We installed 12 continuous GPS sensors spanning 700 km across the rift including Tanzania, Malawi, and Zambia to measure the width and gradient within the actively deforming zone. Most of these stations have 3 or more years of data now, although a few have shorter time series because of station vandalism. Spanning a smaller area, but with higher spatial resolution, we have created a time series of ground deformation using 150 interferograms from the Japanese ALOS-1 satellite spanning June 2007 to December 2010. We also present interferograms from other satellites including ERS, Envisat, and Sentinel spanning shorter time intervals. The observations include the 2009-2010 Karonga earthquake sequence and associated postseismic deformation as seen by multiple independent satellite lines-of-sight, that we model using a fault geometry determined using relocated aftershocks recorded by a local seismic array. We have not found any ground deformation at the Rungwe volcanic province from InSAR within our detection threshold ( 2 cm/yr), but we have observed localized seasonal ground movements exceeding 8 cm that are associated with subsidence in the dry season and uplift at the beginning of the wet season.

  10. Using Envisat InSAR time-series to investigate the surface kinematics of an active salt extrusion near Qum, Iran (United States)

    Abdolmaleki, Nastaran; Motagh, Mahdi; Bahroudi, Abbas; Sharifi, Mohammad Ali; Haghshenas Haghighi, Mahmud


    Lower Oligocene-Miocene rock salt is exposed in several diapirs in the central plateau of Iran along the northern margin of the Great Kavir basin. These include a small but mature salt extrusion known as Qum Kuh located near the city of Qum. We use small-baseline interferograms to study the surface displacements of Qum Kuh. The interferometric dataset consisted of 149 interferometric displacement maps derived from 35 C-band ASAR images collected by Envisat satellite in both descending and ascending orbits from 2003 through 2009.The results of the displacement time series analyses show significant long-term trend of horizontal motion toward gentle slopes of Qum Kuh, punctuated by seasonal variations during dry and wet seasons. Interferometric Synthetic Aperture Radar (InSAR) time series results suggest that the salt near the spreading center, where the salt first surfaces from depth, is extruded to the more gentle flanks of Qum Kuh and that down-slope gravitational spreading of the extruded salt accelerates when it is wet.

  11. Analyzing InSAR Results Using GIS and Its Application on the Coseismic Interpretation of Mw7.9 Wenchuan Earthquake%基于GIS的InSAR结果分析方法及在汶川 Mw7.9级地震同震解释中的应用

    Institute of Scientific and Technical Information of China (English)

    许才军; 江国焰; 王浩; 温扬茂


    利用GIS对InSAR结果进行分析可以更全面地解释地表形变机制.介绍了利用GIS对SAR影像进行裁剪、切割和拼接处理、剖面和等值分析的方法.在此基础上,以汶川Mw7.9级地震为例介绍了基于GIS的InSAR结果分析方法在地震形变机制解释方面的应用:①根据InSAR距离向偏移量和同震形变场,利用GIS技术提取了汶川Mw7.9级地震发震断层的地表迹线;②将基于位错模型正演得到的视线向形变场与InSAR同震形变场进行比较,得到了汶川地区InSAR同震形变场的上盘和整体改正数,进一步借助GIS进行修正得到了更为真实的InSAR同震形变场;③利用2D/3D InSAR同震形变场、干涉纹图和剖面分析结果对汶川Mw7.9级地震同震形变特征进行了具体分析和解释.%InSAR results' analysis assisted with GIS can give more comprehensive interpretation on surface deformation mechanism.In this paper, we present the methods to clip, split and merge SAR images with the help of GIS.Besides, the profile and contour analysis to SAR images are illustrated.In order to demonstrate the effectiveness on interpreting earthquake deformation mechanism using the InSAR results assisted with GIS, we analyze the Mw7.9 Wenchuan earthquake as follows.First, the seismic fault surface trace is extracted according to the InSAR range offset and coseismic deformation field.Second, through the comparison between the LOS deformation field obtained by geophysical forward using dislocation model and the InSAR coseismic deformation field, the whole and hanging wall corrections of InSAR deformation field are obtained, with which the more actual coseismic deformation are got by correction using GIS.Finally, more comprehensive analysis and interpretation on the characteristics of coseismic deformation are presented by using the 2D/3D coseismic deformation field, interferograms and profile analysis.

  12. Analysis on coherence changes of dam surface in TerraSAR Strip mode interferograms (United States)

    Li, Tao; Gong, Chunlong; Xia, Min; Jin, Zonghuang


    The high resolution images of TerraSAR has made it able to reflect the detail characters of large-scale manmade structures, so monitoring local deformation of large-sized buildings comes to be available. Former research had shown that InSAR phase of the dam surface was stable and consecutive. This paper aimed to make a further proof of the viability of monitoring dam's deformation using 3-meter-resolution strip mode images of TerraSAR. So we made a time series analysis of dam surface's coherence for the next step. Our dataset had eleven images covering three medium size basins of Shenzhen. Coherence of different features in the basin area including dams was extracted to make a comparative analysis. Two different combination methods were designed to create interferometric pairs to find the influence of time baseline and perpendicular baseline to coherence of different cultures. In our research, it was find out that coherence of dam surface was mainly influenced by time baseline. In short time baseline pairs (eleven days), coherence of dam surface was about 0.2 higher than vegetation slope in average. DInSAR process was suitable for short time baseline interferometric pairs, other methods such as PS will be needed for long time baseline interferometric pairs.

  13. Activation of the SIGRIS monitoring system for ground deformation mapping during the Emilia 2012 seismic sequence, using COSMO-SkyMed InSAR data

    Directory of Open Access Journals (Sweden)

    Stefano Salvi


    Full Text Available On May 20, 2012, at 02:03 UTC, a moderate earthquake of local magnitude, Ml 5.9 started a seismic sequence in the central Po Plain of northern Italy The mainshock occurred in an area where seismicity of comparable magnitude has neither been recorded nor reported in the historical record over the last 1,000 years. The aftershock sequence evolved rapidly near the epicenter, with diminishing magnitudes until May 29, 2012, when at 07:00 UTC a large earthquake of Ml 5.8 occurred 12 km WSW of the mainshock, starting a new seismic sequence in the western area; a total of seven earthquakes with Ml >5 occurred in the area between May 20 and June 3, 2012. Immediately after the mainshock, the Italian Department of Civil Protection requested the Italian Space Agency to activate the Constellation of Small Satellites for Mediterranean Basin Observation (COSMO-SkyMed to provide Interferometric Synthetic Aperture Radar (InSAR coverage of the area. COSMO-SkyMed consists of four satellites in a 16-day repeat-pass cycle, with each carrying the same SAR payload. In the current orbital configuration, within each 16-day cycle, image pairs with temporal baselines of 1, 3, 4 and 8 days can be formed from the images acquired by the four different sensors. Combined with the availability of a wide range of electronically steered antenna beams with incidence angles ranging from about 16˚ to 50˚ at near-range, this capability allows trade-offs between temporal and spatial coverage to be exploited during acquisition planning. A joint team involving the Istituto Nazionale di Geofisica e Vulcanologia (INGV and the Istituto per il Rilevamento Elettromagnetico dell'Ambiente (IREA-CNR was activated to generate InSAR-based scientific products to support the emergency management. In this framework, the ASI and DPC requested that INGV activated the Space-based Monitoring System for Seismic Risk Management (SIGRIS. SIGRIS consists of a hardware/software infrastructure that is

  14. Application of ALOS and Envisat Data in Improving Multi-Temporal InSAR Methods for Monitoring Damavand Volcano and Landslide Deformation in the Center of Alborz Mountains, North Iran

    Directory of Open Access Journals (Sweden)

    S. Vajedian


    Full Text Available InSAR capacity to detect slow deformation over terrain areas is limited by temporal and geometric decorrelations. Multitemporal InSAR techniques involving Persistent Scatterer (Ps-InSAR and Small Baseline (SBAS are recently developed to compensate the decorrelation problems. Geometric decorrelation in mountainous areas especially for Envisat images makes phase unwrapping process difficult. To improve this unwrapping problem, we first modified phase filtering to make the wrapped phase image as smooth as possible. In addition, in order to improve unwrapping results, a modified unwrapping method has been developed. This method includes removing possible orbital and tropospheric effects. Topographic correction is done within three-dimensional unwrapping, Orbital and tropospheric corrections are done after unwrapping process. To evaluate the effectiveness of our improved method we tested the proposed algorithm by Envisat and ALOS dataset and compared our results with recently developed PS software (StaMAPS. In addition we used GPS observations for evaluating the modified method. The results indicate that our method improves the estimated deformation significantly.

  15. Comparison of Laser and Stereo Optical, SAR and InSAR Point Clouds from Air- and Space-Borne Sources in the Retrieval of Forest Inventory Attributes

    Directory of Open Access Journals (Sweden)

    Xiaowei Yu


    Full Text Available It is anticipated that many of the future forest mapping applications will be based on three-dimensional (3D point clouds. A comparison study was conducted to verify the explanatory power and information contents of several 3D remote sensing data sources on the retrieval of above ground biomass (AGB, stem volume (VOL, basal area (G, basal-area weighted mean diameter (Dg and Lorey’s mean height (Hg at the plot level, utilizing the following data: synthetic aperture radar (SAR Interferometry, SAR radargrammetry, satellite-imagery having stereo viewing capability, airborne laser scanning (ALS with various densities (0.8–6 pulses/m2 and aerial stereo imagery. Laser scanning is generally known as the primary source providing a 3D point cloud. However, photogrammetric, radargrammetric and interferometric techniques can be used to produce 3D point clouds from space- and air-borne stereo images. Such an image-based point cloud could be utilized in a similar manner as ALS providing that accurate digital terrain model is available. In this study, the performance of these data sources for providing point cloud data was evaluated with 91 sample plots that were established in Evo, southern Finland within a boreal forest zone and surveyed in 2014 for this comparison. The prediction models were built using random forests technique with features derived from each data sources as independent variables and field measurements of forest attributes as response variable. The relative root mean square errors (RMSEs varied in the ranges of 4.6% (0.97 m–13.4% (2.83 m for Hg, 11.7% (3.0 cm–20.6% (5.3 cm for Dg, 14.8% (4.0 m2/ha–25.8% (6.9 m2/ha for G, 15.9% (43.0 m3/ha–31.2% (84.2 m3/ha for VOL and 14.3% (19.2 Mg/ha–27.5% (37.0 Mg/ha for AGB, respectively, depending on the data used. Results indicate that ALS data achieved the most accurate estimates for all forest inventory attributes. For image-based 3D data, high-altitude aerial images and WorldView-2

  16. Updated progress in theories and applications of spaceborne SAR interferometry (United States)

    Chen, Yan-Ling; Huang, Cheng; Ding, Xiao-Li; Li, Zhi-Wei


    InSAR (Interferometric Synthetic Aperture Radar) and D-InSAR (Differential InSAR) are rapidly developed new technologies of space geodesy during the late 20th century, and now obviously become hot research topics in the field of microwave remote sensing. Compared with the other sensors, InSAR possesses many incomparable advantages such as the capability to work at all-time and under all weather, very high spatial resolution and strong penetrability through the ground surface. This paper introduces general status of SAR, InSAR, D-InSAR technology, and the principles of InSAR and D-InSAR. New theories and the potential problems of (D-)InSAR technology are largely discussed, including multi-baseline interferometry, Pol-InSAR technique, the correction of atmospheric effects, permanent Scatterers method, the synthesization technique between InSAR and GPS, LIDAR etc., and the InSAR parallel algorithm. Then the new applications of InSAR and D-InSAR are described in detail including 3D topographic mapping, deformation monitoring (including surface subsidence, landside monitoring and ITRF's foundation and maintenance, etc.), thematic mapping (including agriculture and forestry, oceanic surveying and flood monitoring, etc.) and meteorology etc.. Finally, the prospect and future trends in InSAR development are summarized.

  17. Resolving the velocity and strain fields in the Upper Rhine Graben Area from a Combination of Levelling, GNSS and InSAR (United States)

    Westerhaus, Malte; Fuhrmann, Thomas; Mayer, Michael; Zippelt, Karl; Heck, Bernhard


    The Upper Rhine Graben (URG), located in the tri-national region between Germany, France and Switzerland is the most prominent segment of the European Cenozoic rift system. In recent times, the URG area is characterised by small tectonic movements (less than 1 mm/a) and moderate seismicity up to M=5. Historically, earthquake magnitudes exceeding M=6 have been reported showing that the seismic hazard is quite high. The contemporary tectonic surface deformations are superimposed by displacements caused by anthropogenic activities in various locations in the area, such as coal and potash mining, groundwater usage, oil extraction, geothermal energy and CO2 storage. We use data sets from levelling campaigns, InSAR and permanent GNSS sites to raise an inventory of the current 3D surface displacements and strain rates in the URG with high precision and high spatial resolution. Precise levellings carried out by the surveying authorities of Germany, France and Switzerland since the end of the 19th century have been combined to form a network of levelling lines. A kinematic network adjustment is applied on the levelling data, providing an accurate solution for vertical displacement rates at the levelling benchmarks. InSAR is used to fill gaps in the interior of the levelling loops and to significantly increase the number of points. All the available ERS-1/2 and Envisat scenes from two acquisition geometries covering a period from 1992 to 2000 and 2002 to 2010, resp., are processed according to the Persistent-Scatterer approach. In addition, coordinate time series of 76 permanent sites of the GNSS URG Network are used to support the derivation of the horizontal velocity field of the region. Daily GPS-solutions obtained in differential mode are available since 2004. In a first step, estimates of the surface displacement rates are derived from each technique starting from the raw data. Subsequently, the single-technique deformation estimates are mathematically combined to a 3D

  18. SAR Image Texture Analysis of Oil Spill (United States)

    Ma, Long; Li, Ying; Liu, Yu

    Oil spills are seriously affecting the marine ecosystem and cause political and scientific concern since they have serious affect on fragile marine and coastal ecosystem. In order to implement an emergency in case of oil spills, it is necessary to monitor oil spill using remote sensing. Spaceborne SAR is considered a promising method to monitor oil spill, which causes attention from many researchers. However, research in SAR image texture analysis of oil spill is rarely reported. On 7 December 2007, a crane-carrying barge hit the Hong Kong-registered tanker "Hebei Spirit", which released an estimated 10,500 metric tons of crude oil into the sea. The texture features on this oil spill were acquired based on extracted GLCM (Grey Level Co-occurrence Matrix) by using SAR as data source. The affected area was extracted successfully after evaluating capabilities of different texture features to monitor the oil spill. The results revealed that the texture is an important feature for oil spill monitoring. Key words: oil spill, texture analysis, SAR

  19. Joint inversion of GPS, InSAR and teleseismic data sets for the rupture process of the 2015 Gorkha, Nepal, earthquake using a generalized ABIC method (United States)

    Yi, Lei; Xu, Caijun; Zhang, Xu; Wen, Yangmao; Jiang, Guoyan; Li, Mengkui; Wang, Yuebin


    Various observations are made to invert for the source model of the 2015 Gorkha earthquake. Previously published slip models involve different slip distributions and slip amplitudes. To obtain a robust model, we jointly invert for the rupture process of the Gorkha earthquake using three types of observations: Global Positioning System (GPS), Interferometric Synthetic Aperture Radar (InSAR), and teleseismic P wave data. Three constraints (i.e., spatial and temporal smoothness and minimum moment constraints) are applied to regulate the rupture process. The weight ratios between data sets and prior constraints are determined from a new developed generalized Akaike's Bayesian Information Criterion (gABIC) weight determination method. This gABIC method can simultaneously and objectively weigh various kinds of observations and prior constraints, rather than being limited to the two types in the traditional ABIC method. The inverted slip model reveals the seismic moment of the earthquake is 9.40 × 1020 N m released primarily in the first 60 s, equivalent to Mw 7.92. The rupture front propagates unilaterally along the strike direction and spreads in both the strike and dip directions. The slip distribution shows one large slip patch with two peaks along the strike direction with a maximum slip amplitude of approximately 7.6 m and identifies large slips (> 2 m) that occur in the updip section of the Main Himalayan Thrust (MHT) fault plane. Our results indicate that the released slip amplitude is larger than the accumulated slip amplitude since 1833, so the 2015 earthquake likely does not overlap with the 1833 earthquake.

  20. Causes of unrest at silicic calderas in the East African Rift: New constraints from InSAR and soil-gas chemistry at Aluto volcano, Ethiopia (United States)

    Hutchison, William; Biggs, Juliet; Mather, Tamsin A.; Pyle, David M.; Lewi, Elias; Yirgu, Gezahegn; Caliro, Stefano; Chiodini, Giovanni; Clor, Laura E.; Fischer, Tobias P.


    Restless silicic calderas present major geological hazards, and yet many also host significant untapped geothermal resources. In East Africa, this poses a major challenge, although the calderas are largely unmonitored their geothermal resources could provide substantial economic benefits to the region. Understanding what causes unrest at these volcanoes is vital for weighing up the opportunities against the potential risks. Here we bring together new field and remote sensing observations to evaluate causes of ground deformation at Aluto, a restless silicic volcano located in the Main Ethiopian Rift (MER). Interferometric Synthetic Aperture Radar (InSAR) data reveal the temporal and spatial characteristics of a ground deformation episode that took place between 2008 and 2010. Deformation time series reveal pulses of accelerating uplift that transition to gradual long-term subsidence, and analytical models support inflation source depths of ˜5 km. Gases escaping along the major fault zone of Aluto show high CO2 flux, and a clear magmatic carbon signature (CO2-δ13C of -4.2‰ to -4.5‰). This provides compelling evidence that the magmatic and hydrothermal reservoirs of the complex are physically connected. We suggest that a coupled magmatic-hydrothermal system can explain the uplift-subsidence signals. We hypothesize that magmatic fluid injection and/or intrusion in the cap of the magmatic reservoir drives edifice-wide inflation while subsequent deflation is related to magmatic degassing and depressurization of the hydrothermal system. These new constraints on the plumbing of Aluto yield important insights into the behavior of rift volcanic systems and will be crucial for interpreting future patterns of unrest.

  1. 一种改进的Goldstein InSAR干涉图滤波算法%A Modified Goldstein Algorithm for InSAR Interferogram Filtering

    Institute of Scientific and Technical Information of China (English)

    于晓歆; 杨红磊; 彭军还


    提出了一种抑制InSAR干涉图噪声并保持干涉图条纹细节的算法,该算法改进了Goldstein滤波的参数α,将干涉图的相位标准偏差函数模型作为参数。相位标准偏差是相位噪声的体现,以干涉图的相位噪声强弱来决定滤波的强弱,噪声强的局部区域强滤波,噪声弱的局部区域弱滤波。实验结果表明,此方法改善了滤波效果,增强了滤波的局部自适应性和条纹细节的保真性。%An algorithm for filtering InSAR phase noise and preserving details of interferometric fringes is proposed,which improves Goldstein filtering parameter α and considers function of standard deviation of phase to be parameter.The standard deviation of phase shows phase noise effectively.According to degree of interferogram phase noise,the method can determine degree of filter strength.The modification can make the local area with strong noise strongly filtered,while those with week noise weekly filtered.Experimental results with both the simulated data sets and the real one show that the new method can improve filtering effect and enhance the local adaptability of the filter and fidelity details of interferometric fringes.

  2. 一种改正InSAR大气延迟的新方法%A new method for InSAR Atmospheric Delay Correction

    Institute of Scientific and Technical Information of China (English)

    傅拓; 张书毕


    InSAR技术是近二十几年来迅速发展的极具应用价值的空间对地观测新技术,具有监测精度高、范围大、成本低、空间连续覆盖等优点,为滑坡、泥石流等地质灾害监测提供了一种新型的监测方法。但由于地质灾害多发生在暴雨频发、地质地貌复杂的区域,特殊的地理位置与气候使得InSAR技术应用中受大气延迟的影响非常严重,导致In-SAR图像错误解释。本文在全面回顾当前主流的几种改正InSAR大气延迟的方法在国内外滑坡监测中的应用现状和实例的基础上,分析这几种技术的优势及问题点,并结合最新技术进展提出了一种基于GPS和NCEP FNL数据改正InSAR大气延迟的新方法并详细推导了该方法处理的流程,证明了其可行性。%Interferometric Synthetic Aperture Radar(InSAR)has been widely used to monitor geological hazards due to its high precision,wide area coverage and low cost.However,InSAR suffers from the phase delay in radio signal propagation through the atmosphere,and it becomes worse during the geological hazards always occur in complex geological hilly areas with heavy rainfalls.Then based on a detailed review for the application studies to some main-flow subjects so far in the world,the advantages and difficulties concerning the application of these skills to landslide monitoring are concluded.By means of some new developments of monitoring technique,possible solutions for the existing problems to practical application of InSAR atmospheric delay correction based on GPS observations and NCEP FNLdata are proposed.This paper introduces the derivation principles and processing method of this technique,proving the application.

  3. Waterline extraction in optical images and InSAR coherence maps based on the geodesic time concept (United States)

    Soares, Fernando; Nico, Giovanni


    An algorithm for waterline extraction from SAR images is presented based on the estimation of the geodesic path, or minimal path (MP) between two pixels on the waterline. For two given pixels, geodesic time is determined in terms of the time shortest path, between them. The MP is determined by estimating the mean value for all pairs of neighbor pixels that can be part of a possible path connecting the initial given pixels. A MP is computed as the sum of those two geodesic image functions. In general, a MP is obtained with the knowledge of two end pixels. Based on the 2-dimensional spreading of the estimated geodesic time function, the concepts of propagation energy and strong pixels are introduced and tested for the waterline extraction by marking only one pixel in the image.

  4. Ambiguity noise analysis of a SAR system (United States)

    Tian, Haishan; Chang, Wenge; Li, Xiangyang


    The presence of range and azimuth (or Doppler) ambiguities in synthetic aperture radars (SARs) is well known. The ambiguity noise is related to the antenna pattern and the value of pulse repetition frequency (PRF). Because a new frequency modulated continuous wave (FMCW) SAR has the characters of low cost and small size, and the capacity of real-time signal processing, the antenna will likely vibrate or deform due to a lack of the stabilized platform. And the value of PRF cannot be much high because of the high computation burden for the real-time processing. The aim of this study is to access and improve the performance of a new FMCW SAR system based on the ambiguity noise. First, the quantitative analysis of the system's ambiguity noise level is performed; an antenna with low sidelobes is designed. The conclusion is that the range ambiguity noise is small; the azimuth ambiguity noise is somewhat increased, however, it is sufficiently small to have marginal influence on the image quality. Finally, the ambiguity noise level is measured using the imaging data from a Ku-band FMCW SAR. The results of this study show that the measured noise level coincides with the theoretical noise level.

  5. VERITAS (Venus Emissivity, Radio Science, InSAR, Topo-graphy And Spectroscopy): A Proposed Discovery Mission (United States)

    Smrekar, Suzanne; Dyar, Melinda; Hensley, Scott; Helbert, Joern; VERITAS Science Team


    VERITAS addresses one of the most fundamental questions in planetary evolution: How Earth-like is Venus? These twin planets diverged down different evolutionary paths, yet Venus may hold lessons for past and future Earth, as well as for Earth-sized exoplanets. VERITAS will search for the mineralogical fingerprints of past water, follow up on the discoveries of recent volcanism and the possible young surface age, and reveal the conditions that have prevented plate tectonics from developing. Collectively these questions address how Venus ended up a sulfurous inferno while Earth became habitable.VERITAS carries the Venus Interferometric Synthetic Aperture Radar (VISAR) and the Venus Emissivity Mapper (VEM), plus a gravity science investigation.The VISAR X-band radar produces: 1) a global digital elevation model (DEM) with 250 m postings, 5 m height accuracy, 2) Synthetic aperture radar (SAR) global imaging with 30 m pixels, 3) SAR imaging at 15 m for targeted areas, and 4) surface deformation from repeat pass interferometry (RPI) at 2 mm height precision for targeted, potentially active areas. VEM [see Helbert abstract] will measure surface emissivity, look for active volcanic flows and outgassing of water over ~78% of the surface using 6 NIR surface bands within 5 atmospheric windows and 8 bands for calibration of clouds, stray light, and water vapor.VERITAS uses Ka-band uplink and downlink to create a global gravity field with 3 mgal accuracy and 145 km resolution (130 spherical harmonic degree and order or d&o) and providing a significantly higher resolution field with much more uniform resolution than that available from Magellan.VERITAS will create a rich data set of high resolution topography, imaging, spectroscopy, and gravity. These co-registered data sets will be on par with those acquired for Mercury, Mars and the Moon that have revolutionized our understanding of these bodies. VERITAS would be a valuable asset for future lander or probe missions, collecting

  6. On the use of SAR interferometry to aid navigation of UAV (United States)

    Nitti, Davide O.; Bovenga, Fabio; Morea, Alberto; Rana, Fabio M.; Guerriero, Luciano; Greco, Mario; Pinelli, Gianpaolo


    This study is aimed at exploring the potentials of SAR Interferometry (InSAR) to aid Unmanned Aerial Vehicles (UAV) navigation. The basic idea is to infer both position and attitude of an aerial platform by inspecting the InSAR phase derived by a real time SAR interferometer mounted onboard the platform. Thanks to the expected favorable conditions in terms of geometrical sensitivity as well as signal coherence, the InSAR phase field can be used to derive the terrain elevation. By using both approximated position and attitude values of the platform as well as a reference Digital Terrain Model (DTM) from a mission database available onboard, it is possible to generate a synthetic InSAR phase model to be compared w.r.t. that derived by SAR observations. The geometrical transformation needed to match these two terrain models depends on the difference between position and attitude values derived by the instruments available on board and their actual values. Hence, this matching provides a feedback to be used for adjusting position and attitude. In order to assess the reliability of the proposed approach, we evaluated the interferometric sensitivity to changes in position and attitude. This analysis defines the limits of applicability of the InSAR-based approach and provides indications and requirements on geometric and radiometric parameters.


    Institute of Scientific and Technical Information of China (English)

    剧成宇; 师艳; 孙建勇; 吴剑光; 邓喀中


    基于GPS和InSAR大气延迟的关联性和空间分辨率的差异,利用PSO(Particle Swarm Optimization)优化算法辅助LSSVM( Least Square Support Vector Machine)寻求最优参数对GPS大气延迟进行插值,以实现GPS对InSAR大气延迟进行逐像元改正.分析证明,利用GPS技术改正InSAR大气延迟值约为30 mm,显著提高了InSAR技术精度.%The atmospheric delay has limited the application of InSAR in the field of deformation monitoring and so on. On the basis of relationship and difference of the spatial resolution of the GPS and InSAR atmospheric delay, optimizing LSSVM parameters by the PSO algorithm, and interpolating the GPS atmospheric delay, then correcting the InSAR atmospheric delay are carried out pixel by pixel. Through the experiment and analysis, the InSAR atmospheric delay could be corrected about 30 mm by GPS to improve the InSAR precision in the experiment region.

  8. Decrypting geophysical signals at Stromboli Volcano (Italy): Integration of seismic and Ground-Based InSAR displacement data. (United States)

    Di Traglia, F; Cauchie, L; Casagli, N; Saccorotti, G


    We present the integration of seismic and Ground-Based Interferometric Synthetic Aperture Radar system (GBInSAR) displacement data at Stromboli Volcano. Ground deformation in the area of summit vents is positively correlated with both seismic tremor amplitude and cumulative amplitudes of very long period (VLP) signals associated with Strombolian explosions. Changes in VLP amplitudes precede by a few days the variations in ground deformation and seismic tremor. We propose a model where the arrival of fresh, gas-rich magma from depth enhances gas slug formation, promoting convection and gas transfer throughout the conduit system. At the shallowest portion of the conduit, an increase in volatile content causes a density decrease, expansion of the magmatic column and augmented degassing activity, which respectively induce inflation of the conduit, and increased tremor amplitudes. The temporal delay between increase of VLP and tremor amplitudes/conduit inflation can be interpreted in terms of the different timescales characterizing bulk gas transfer versus slug formation and ascent.

  9. Characterization of Anthropogenic Land Subsidence, its Relation to Fault System Geometry, and Their Consequences for Water Table Position in the El Paso, Texas Area Using InSAR and Gravity (United States)

    Schiek, C. G.; Leuro, E.; Buckley, S.; Hurtado, J. M.


    The Hueco and Mesilla basins, located in the westernmost part of Texas and the southernmost part of New Mexico, are part of the Rio Grande Aquifer system. This aquifer system is the major water source for New Mexico, west Texas, and Mexico, including the cities of El Paso and Ciudad Juarez. The aquifer system lies within the Rio Grande Rift system, which spans the eastern edge of the Basin and Range province. Normal faults defining the Rio Grande Rift put structural and stratigraphic controls on aquifer systems such as those in the Mesilla and Hueco basins. These faults define stratigraphic controls on the aquifer by placing compacted rock next to unconsolidated and unsorted sediments, and act as conduits for water flow from the surface to the subsurface. We combine InSAR and gravity measurements to determine the location and geometry of subsurface faults within the basins. These faults can determine the shape and extent of observed land subsidence, which is a consequence of increased water pumping since the early 20th century. In addition, hydrologic information about the Rio Grande aquifer system, such as aquifer flow, compaction, and basin stratigraphy are compared with the InSAR results in order to determine how the subsidence is affecting the water table. Finally, subsidence patterns can indicate the presence and geometry of subsurface faults that may pose seismic hazards.

  10. 改进的基于最大似然估计的多通道InSAR高程重建方法%Improved Multichannel InSAR Height Reconstruction Method Based on Maximum Likelihood Estimation

    Institute of Scientific and Technical Information of China (English)

    袁志辉; 邓云凯; 李飞; 王宇; 柳罡


    In the application of getting the earth surface’s Digital Elevation Model (DEM) through InSAR technology, multichannel (multi-frequency or multi-baseline) InSAR technique can be employed to improve the mapping ability for complex areas with high slopes or strong height discontinuities, and solve the ambiguity problem which existed in the situation of single baseline. This paper compares the performance of Maxmum Likelihood (ML) estimation techniques with Maximum A Posteriori (MAP) estimation techniques, and adds two steps of bad pixels judgment and weighted filtering after the ML estimation. Bad pixels judgment is completed through cluster analysis and the relationship between adjacent pixels. A special weighted mean filter is used to remove the bad pixels. In this way, the advantage of the ML method’s good efficiency is kept, and the accuracy of DEM also is improved. Simulation results indicate that this method can not only keep good accuracy but also improve greatly the computation efficiency under the same condition, which is advantageous for processing large scale of data sets.%在通过InSAR技术获取地表数字高程模型(DEM)的应用中,为了提高该技术对大斜坡或突变等复杂地形的测绘能力,解决单基线情况下的高度模糊问题,可以利用多通道(多频率或多基线)InSAR技术实现。该文比较了最大似然估计法(ML)和最大后验概率估计法(MAP)的性能,并在最大似然估计法的基础上增加了坏点判断和加权均值滤波的环节,通过聚类分析和与相邻点的关系来判断目标像素是否为误差比较大的坏点,然后再利用加权均值滤波的方法将这些坏点剔除。这样,既保留了ML估计法速度快的特点,又提高了DEM的精度。仿真结果表明,在相同条件下,该方法既能保持较好的精度,同时又大大提高了算法的运行效率,非常有利于大规模数据的处理。

  11. Sinking Chao Phraya delta plain, Thailand, derived from SAR interferometry time series analysis (United States)

    Tanaka, A.; Mio, A.; Saito, Y.


    The Bangkok Metropolitan region and its surrounding provinces are located in a low-lying delta plain of the Chao Phraya River. Extensive groundwater use from the late 1950s has caused the decline of groundwater levels in the aquifers and Holocene clay compaction beneath the Bangkok Region, resulting in significant subsidence of the ground. This ground deformation has been monitored using leveling surveys since 1978, and differential InSAR (Interferometric Synthetic Aperture Radar) analysis. It shows that the Bangkok Metropolitan region is subsiding at a rate of about 20 mm/year during the recent years due to law-limited groundwater pumping, although the highest subsidence rate as high as 120 mm/year was recorded in 1981. The subsidence rate in the Bangkok area has significantly decreased since the late 1980s; however, the affected area has spread out to the surrounding areas. The maximum subsidence rate up to 30 mm/year occurred in the outlying southeast and southwest coastal zones in 2002. In this study, we apply a SAR interferometry time series analysis to monitor ground deformations in the lower Chao Phraya delta plain (Lower Central Plain), Thailand, using ALOS (Advanced Land Observing Satellite) PALSAR (Phased Array type L-band SAR) data acquired between July 2007 and September 2010. We derive a single reference time series interferogram from the stacking of unwrapped phases under the assumptions that those phases are smoothly and continuously connected, and apply a smoothness-constrained inversion algorithm that optimizes the displacement from the phase unwrapping of multitemporal differential SAR interferograms. The SAR interferometry time series analysis succeeds to monitor the incremental line-of-sight (LOS)-change between SAR scene acquisitions. LOS displacements are converted to vertical displacements, based on the assumption that the ground displacement in this area occurs only in the vertical directions. This reveals an overall pattern of subsidence

  12. Coseismic slip solution and preliminary postseismic results for the 7 December 2015 Mw 7.2 Sarez Lake, Tajikistan earthquake from joint inversion of Sentinel­-1A and ALOS­-2 InSAR data (United States)

    Sangha, S.; Peltzer, G.; Liang, C.; Bekaert, D. P.; Fielding, E. J.


    The 7 December, 2015, Mw 7.2 Sarez Lake earthquake occurred on the sinistral-normal, NNE striking Sarez-Karakul fault system, situated in the Gorno-Badakhshan Autonomous region of Tajikistan, in the central Pamir. Previous geodetic investigations suggest that the region accommodates pure-shear deformation with N-S compression and E-W extension. We study the coseismic and postseismic phases of the deformation associated with this event using S1A and ALOS-2 SAR data, complemented by Landsat-8 images for constraining the fault geometry. InSAR data was processed with the ISCE software and interferograms were phase unwrapped conservatively using the branch-cut algorithm, where manual cuts and bridges were added to retrieve most of the coherent phase in the highly deformed region near the fault. We invert the coseismic interferograms to solve for the fault dip angle, slip, and rake using a Bayesian inversion method based on a Markov­ chain Monte Carlo sampling of the parameter space. Our model includes 3 segments (each divided into 5x5 km2 patches) following the trace inferred from InSAR fringe patterns and horizontal shifts obtained by image correlation of pre- and post-mainshock Landsat-8 images. The solution shows that the fault is near-vertical and the slip mostly left-lateral, consistent with the centroid moment tensor. Most of the moment is released along the fault section that extends 25 km NE from the epicenter and down to a depth of 12 km. A secondary patch of slip occurs at a larger depth on the central segment where the fault makes a right-step in the Karakul Valley. Building postseismic InSAR time series will help us understand postseismic relaxation processes and the lithospheric rheology of the Pamir. Extreme relief and abundant snow cover require careful processing to mitigate the signal due to the tropospheric phase delay and unwrapping errors. We use global weather models to estimate the interferometric phase delay produced by tropospheric variability

  13. High-resolution InSAR constraints on flood-related subsidence and evaporite dissolution along the Dead Sea shores: Interplay between hydrology and rheology (United States)

    Shviro, Maayan; Haviv, Itai; Baer, Gidon


    Sinkhole generation and land subsidence are commonly attributed to dissolution of subsurface layers by under-saturated groundwater and formation of cavities. Along the Dead Sea (DS) shorelines, this process also involves seasonal flash floods that are drained into the subsurface by existing and newly formed sinkholes. We quantify the contribution of flash-floods to salt dissolution and land subsidence using high-resolution interferometric synthetic aperture radar (InSAR). Subsidence rates during a 3-year period (2012-2015) were calculated from 57 COSMO SkyMed X-band interferograms bracketing major flood events and intra-flood periods in 21 sinkhole sites. The sites are located within channels and alluvial fans along the western shores of the Dead Sea, Israel. The observed subsidence reaches maximum rates of 2.5 mm/day, accumulating in specific sites to 500 mm/year. In most of the sinkhole sites a gradual increase in the annual subsidence rate is observed during the 3-year study period. Three different modes of response to floods were observed: (1) sites where floodwater is not directly channeled into sinkholes do not respond to floods; (2) sites adjacent to active channels with sinkholes are unaffected by specific floods but their subsidence rates increase gradually from early winter to mid-summer, and decay gradually until the following winter; and (3) sites in active channels with sinkholes are characterized by an abrupt increase in subsidence rates immediately after each flood (by a factor of up to 20) and by a subsequent quasi-exponential subsidence decay over periods of several months. In these latter sites, subsidence rates after each flood are temporally correlated with alternating groundwater levels in adjacent boreholes. The rapid rise in groundwater head following floods increases the hydraulic gradient of the under-saturated groundwater and hence also the groundwater discharge and the dissolution rate of the subsurface salt layer. A subsequent quasi

  14. Lava Lake Level Drop and Related Ground Subsidence in the Nyiragongo Main Crater (D.R.Congo) Measured by Close-Range Photogrammetry and InSAR Time-Series (United States)

    Smets, B.; d'Oreye, N.; Samsonov, S. V.; Nobile, A.; Geirsson, H.; Kervyn, F.


    Nyiragongo volcano is the most active African volcano and among the most active volcanoes on Earth. It is also among the infrequent volcanoes that host a long-lived lava lake. The morphology of the Nyiragongo main crater is characterized by 2 levels of remnant platforms partly preserved and attached to its inner flanks, which correspond to former lava lake levels, and by a bottom "active" platform, which delimits the current active lava lake. The elevation of the bottom platform increases through time, with successive lava lake overflows. After a period of low level between late 2010 and August 2011, the lava lake next came back to its highest level. However, on September 30, 2011, it started a long and progressive fall, reaching ~70 m below the bottom platform in July 2014. This recent evolution of the lava lake, which occurred at the same time period as eruptive events at the neighboring Nyamulagira volcano, was accompanied by a ground subsidence of the bottom platform, leading to the appearance of ring fissures. This ground deformation is restricted to the bottom platform and, hence, suggests a very shallow source for the observed movement. All these changes in the Nyiragongo main crater were recorded by time-series of photographs, allowing the 3D reconstruction of the crater using close-range photogrammetric techniques and, hence, a detailed measurement of the observed changes. The ground subsidence was also recorded by time-series of RADARSAT-2 and CosmoSky-Med SAR interferograms, providing more detailed information on the velocity of deformation. Based on field data and the photogrammetric and InSAR time-series measurements, several hypotheses on the cause(s) of these changes in the Nyiragongo crater are discussed. The present work also highlights the potential of close-range photogrammetry and high-resolution InSAR to study and monitor active volcanoes in Equatorial environment.

  15. Resolution analysis of bistatic SAR (United States)

    Garza, Guillermo; Qiao, Zhijun


    In this paper, we analyze the resolution of bistatic synthetic aperture radar (BISAR) imaging for stationary objects. In particular, we analyze the resolution of images reconstructed by the method of a filtered backprojection inversion, an inversion method which is derived from a scalar wave equation model. In this context we are able to account for the effects of antenna beam patterns and arbitrary flight trajectories. The analysis is done by examining the data collection manifold for different experiment geometries and system parameters.

  16. Subsidence Monitoring over the Southern Coalfield, Australia Using both L-Band and C-Band SAR Time Series Analysis

    Directory of Open Access Journals (Sweden)

    Zheyuan Du


    Full Text Available Land subsidence is a global issue and researchers from all over the world are keen to know the causes of deformation and its further influences. This paper reports the findings from time series InSAR (TS-InSAR results over the Southern Coalfield, Australia using both ALOS-1 PALSAR (Phased Array type L-band Synthetic Aperture Radar and ENVISAT ASAR (Advanced Synthetic Aperture Radar datasets. TS-InSAR has been applied to both rural and urban areas with great success, but very few of them have been applied to regions affected by underground mining activities. The TS-InSAR analysis exploited in this paper is based on GEOS-ATSA, and Measurement Point (MP pixels are selected according to different geophysical features. Three experiment sites with different geological settings within the study zone are analysed: (1 Wollongong city, which is a relatively stable area; (2 Tahmoor town, a small town affected by underground mining activities; and (3 the Appin underground mining site, a region containing multiple underground mining activities. The TS-InSAR results show that the performance of both C-band and L-band is equally good over Wollongong, where the subsidence gradient is not significant and most subsidence rates are between −10 mm∙yr−1 to 10 mm∙yr−1. However, over the Tahmoor and Appin sites, difference in performances has been observed. Since the maximum displacement gradients that can be detected are different for L-band and C-band-based TS-InSAR methods, some rapid changes could cause the TS-InSAR to fail to estimate the correct displacements. It is well known that L-band can perform better than C-band, especially in underground mining regions and mining-affected regions where the deformation rate is much higher than city areas because of its wavelength. Statistical analyses are also conducted to further prove the above statement.

  17. Spaceborne Polarimetric SAR Interferometry: Performance Analysis and Mission Concepts

    Directory of Open Access Journals (Sweden)

    Cloude Shane R


    Full Text Available We investigate multichannel imaging radar systems employing coherent combinations of polarimetry and interferometry (Pol-InSAR. Such systems are well suited for the extraction of bio- and geophysical parameters by evaluating the combined scattering from surfaces and volumes. This combination leads to several important differences between the design of Pol-InSAR sensors and conventional single polarisation SAR interferometers. We first highlight these differences and then investigate the Pol-InSAR performance of two proposed spaceborne SAR systems (ALOS/PalSAR and TerraSAR-L operating in repeat-pass mode. For this, we introduce the novel concept of a phase tube which enables (1 a quantitative assessment of the Pol-InSAR performance, (2 a comparison between different sensor configurations, and (3 an optimization of the instrument settings for different Pol-InSAR applications. The phase tube may hence serve as an interface between system engineers and application-oriented scientists. The performance analysis reveals major limitations for even moderate levels of temporal decorrelation. Such deteriorations may be avoided in single-pass sensor configurations and we demonstrate the potential benefits from the use of future bi- and multistatic SAR interferometers.

  18. Was Miyakejima undergoing subsidence before the 2000 caldera collapse? JERS1 InSAR results: 1992-1998 (United States)

    Furuya, M.


    Miyakejima volcano is a basaltic strato volcano island on the eastern edge of the Philippine Sea Plate, and was undergoing a number of eruption activities over the past centuries. In July-August 2000, the Miyakejima volcano underwent a caldera collapse, prompting many modern geodetic and geophysical measurements (e.g., Geshi et al. 2002; Furuya et al. 2003). The observation results on the pre-caldera-collapse stages are, however, limitted. Were there any precursory secular subsidence before the collapse? Though Miyazaki (1990) reported a secular subsidence at the Miyakejima, using leveling technique, there are no documented reports, to my knowledge, which employed radar interferometry to examine the ground displacements at Miyakejima. Here I will report on the results derived from the radar interferometry at Miyakejima volcano. I chose JERS-1 data (L-band HH) for the analysis, so that I could get rid of the loss of coherence; most of the Miyakejima is covered with vegetation. To remove the topographic fringes as well as to re-estimate the spatial baseline data (Rosen et al. 1996), I employed 10-meter resolution digital elevation map derived by Geographical Survey Institute, Japan. I could generate 24 differential interferograms at the time of writing this text. However, I do not yet recognize any significant "signals" that can be discriminated with the atmospheric "noise". There appears to be no specific subsidence pattern, which are detected in a number of other volcanos in the world (e.g., Lu et al. 2002; Yarai et al. 2002; Okuyama et al. 2002). I am going to show a stacked interferogram like that in Fujiwara et al. (1998) and to examine the existence of volcanic signals.

  19. Using 20 years of SAR acquisitions to provide a highly accurate continent wide InSAR phase based ice velocity map (United States)

    Mouginot, J.; Rignot, E. J.; Scheuchl, B.; Li, X.


    During the last years, the mapping of surface ice velocity at continental scale (Greenland, Antarctica) has been realized mainly from feature (Landsat) and speckle tracking techniques assuming 2-D parallel flow. The precision of such mappings is limited by the resolution of the raw images acquired by the satellite sensors, typically around 10 meter. Thus, the recent mappings of Antarctica or Greenland reach, at best, precision in velocity of tens of meters per year, which is not enough to observe the flow close to the divides where horizontal velocity is smaller than 1 meter per year. Another technique consists in combining the ascending/descending interferogram phases from synthetic aperture radar. Although this technique is 10 to 100 times more accurate than tracking, it remains challenging to use at the continental scale. Phase analysis requires more data (ascending and descending), phase unwrapping remains difficult in areas with complex motion patterns, and calibration requirements are more stringent due to the increased accuracy. Here, we present for the first time a new innovative approach to calibrate and combine the unwrapped phases acquired by 11 different sensors during the last 2 decades (ERS1&2, RADARSAT1&2, ALOS1&2, TSX, COSMO-SkyMed, Envisat/ASAR, Sentinel-1a&b) in Antarctica. In areas where it is possible (more than 3 different passes), we reconstruct the flow in 3-D instead of the traditional 2-D parallel flow. The new 3-D view of flow, especially close to the divides, is compared with the 2-D parallel assumption, as well as the balance velocity and the rate of accumulation from surface mass balance. Finally, these results help to evaluate and prepare the workflow for the coming NASA/ISRO mission NISAR to map the ice sheets at unprecedented accuracy using ascending/descending phases.The study is made possible thanks to 5 space agencies (NASA, ESA, JAXA, DLR, ASI) and the coordination from the Polar Space Task Group. This work was performed at UCI

  20. Crop identification of SAR data using digital textural analysis (United States)

    Nuesch, D. R.


    After preprocessing SEASAT SAR data which included slant to ground range transformation, registration to LANDSAT MSS data and appropriate filtering of the raw SAR data to minimize coherent speckle, textural features were developed based upon the spatial gray level dependence method (SGLDM) to compute entropy and inertia as textural measures. It is indicated that the consideration of texture features are very important in SAR data analysis. The SEASAT SAR data are useful for the improvement of field boundary definitions and for an earlier season estimate of corn and soybean area location than is supported by LANDSAT alone.

  1. Constraints on the mechanism of long-term, steady subsidence at Medicine Lake volcano, northern California, from GPS, leveling, and InSAR (United States)

    Poland, Michael P.; Burgmann, Roland; Dzurisin, Daniel; Lisowski, Michael; Masterlark, Timothy; Owen, Susan; Fink, Jonathan


    Leveling surveys across Medicine Lake volcano (MLV) have documented subsidence that is centered on the summit caldera and decays symmetrically on the flanks of the edifice. Possible mechanisms for this deformation include fluid withdrawal from a subsurface reservoir, cooling/crystallization of subsurface magma, loading by the volcano and dense intrusions, and crustal thinning due to tectonic extension (Dzurisin et al., 1991 [Dzurisin, D., Donnelly-Nolan, J.M., Evans, J.R., Walter, S.R., 1991. Crustal subsidence, seismicity, and structure near Medicine Lake Volcano, California. Journal of Geophysical Research 96, 16, 319-16, 333.]; Dzurisin et al., 2002 [Dzurisin, D., Poland, M.P., Bürgmann, R., 2002. Steady subsidence of Medicine Lake Volcano, Northern California, revealed by repeated leveling surveys. Journal of Geophysical Research 107, 2372, doi:10.1029/2001JB000893.]). InSAR data that approximate vertical displacements are similar to the leveling results; however, vertical deformation data alone are not sufficient to distinguish between source mechanisms. Horizontal displacements from GPS were collected in the Mt. Shasta/MLV region in 1996, 1999, 2000, 2003, and 2004. These results suggest that the region is part of the western Oregon block that is rotating about an Euler pole in eastern Oregon. With this rotation removed, most sites in the network have negligible velocities except for those near MLV caldera. There, measured horizontal velocities are less than predicted from ∼10 km deep point and dislocation sources of volume loss based on the leveling data; therefore volumetric losses simulated by these sources are probably not causing the observed subsidence at MLV. This result demonstrates that elastic models of subsurface volume change can provide misleading results where additional geophysical and geological constraints are unavailable, or if only vertical deformation is known. The deformation source must be capable of causing broad vertical deformation

  2. The 2009 Magmatic Intrusion and Faulting in Harrat Al-Shaqah (Lunayyir), western Saudi Arabia, Observed by Satellite Radar Interferometry (InSAR) (Invited) (United States)

    Jonsson, S.; Lu, Z.; El-Hadidy, S.; Zahran, H.


    One of the volcanic provinces in western Saudi Arabia, Harrat Al-Shaqah (also known as Harrat Lunayyir), suffered from numerous small to moderate-size earthquakes in May-July 2009. The most intensive activity occurred on 17-19 May when six magnitude 4.6-5.7 earthquakes occurred. Following the events the Saudi Civil Protection Agency evacuated the area and relocated over 20000 people to the neighboring cities of Yanbu and Medina. The activity continued throughout June with several magnitude 4-5 earthquakes but then quieted down in July. Following the activity in mid-May we sent a request for emergency satellite radar data acquisitions to the European Space Agency and later activated an International Charter to guarantee satellite data collection of the area. We have analyzed a number of satellite radar interferograms (InSAR) of the activity and the results are outstanding, owing to the stable surface conditions of this near vegetation-free region. Interferograms spanning the activity in mid-May exhibit strong deformation that extends across a large 40 km x 40 km area, showing over a meter of WSW-ENE extension. In addition, the data show clear signs of surface faulting and graben-like subsidence in the middle of the deformed area with the graben subsidence exceeding 50 cm. The deformation appears to be caused by a near-vertical dike intrusion with a WNW-ESE orientation, parallel to the Red Sea rift, and the intruded volume is of the order of 0.1 cubic km. The dike caused faulting on graben-forming normal faults. The shallowest part of the dike appears to have reached within only 2-3 km of the surface, right below where the graben is the narrowest and under an area with a number of cinder cones from previous volcanic events. The dike appears to have continued to grow after the initial strong phase of activity in mid-May, as a deformation interferogram spanning the time period from the end of may until early July shows similar deformation pattern, although with a much


    Directory of Open Access Journals (Sweden)

    M. Maghsoudi


    Full Text Available Geomorphology is briefly the study of landforms and their formative processes on the surface of the planet earth as human habitat. The landforms evolution and the formative processes can best be studied by technologies with main application in study of elevation. Interferometric Synthetic Aperture Radar (InSAR is the appropriate technology for this application. With phase differences calculations in radar waves, the results of this technology can extensively be interpreted for geomorphologic researches. The purpose of the study is to review the geomorphologic studies using InSAR and also the technical studies about InSAR with geomorphologic interpretations. This study states that the InSAR technology can be recommended to be employed as a fundamental for geomorphology researches.

  4. Mechanical constraints on inversion of coseismic geodetic data for fault slip and geometry: Example from InSAR observation of the 6 October 2008 Mw 6.3 Dangxiong-Yangyi (Tibet) earthquake (United States)

    Sun, Jianbao; Johnson, Kaj M.; Cao, Zhongquan; Shen, Zhengkang; Bürgmann, Roland; Xu, Xiwei


    Modern geodetic techniques, such as the global positioning system (GPS) and Interferometric Synthetic Aperture Radar (InSAR), provide high-precision deformation measurements of earthquakes. Through elastic models and mathematical optimization methods, the observations can be related to a slip distribution model. The classic linear, kinematic, and static slip inversion problem requires specification of a smoothing norm of slip parameters and a residual norm of the data and a choice about the relative weight between the two norms. Inversions for unknown fault geometry are nonlinear and, therefore, the fault geometry is often assumed to be known for the slip inversion problem. We present a new method to invert simultaneously for fault slip and fault geometry assuming a uniform stress drop over the slipping area of the fault. The method uses a full Bayesian inference method as an engine to estimate the posterior probability distribution of stress drop, fault geometry parameters, and fault slip. We validate the method with a synthetic data set and apply the method to InSAR observations of a moderate-sized normal faulting event, the 6 October 2008 Mw 6.3 Dangxiong-Yangyi (Tibet) earthquake. The results show a 45.0 ± 0.2° west dipping fault with a maximum net slip of ˜1.13 m, and the static stress drop and rake angle are estimated as ˜5.43 MPa and ˜92.5°, respectively. The stress drop estimate falls within the typical range of earthquake stress drops known from previous studies.

  5. Validation of burst overlapping for ALOS-2 PALSAR-2 ScanSAR-ScanSAR interferometry (United States)

    Natsuaki, Ryo; Motohka, Takeshi; Ohki, Masato; Watanabe, Manabu; Suzuki, Shinichi


    The Phased Array type L-band Synthetic Aperture Radar-2 (PALSAR-2) aboard the Advanced Land Observing Satellite- 2 (ALOS-2, "DAICHI-2") is the latest L-band spaceborne synthetic aperture radar (SAR). PALSAR-2 observes the world mainly with 10 m resolution / 70 km swath Stripmap mode and 25 m resolution / 350 km swath ScanSAR mode. The 3-m resolution Stripmap mode is mainly used upon Japan. 350 km ScanSAR observation could detect large scale deformation e.g., the Mw 7.8 Gorkha, Nepal earthquake and its aftershocks in 2015. ALOS-2 ScanSAR is the first one that supports ScanSAR-ScanSAR interferometry in L-band spaceborne SAR. However, because of the parameter setting error for the orbit estimation, ALOS-2 PALSAR-2 ScanSAR could achieve little number of interferometric pair until the software modification on February 8, 2015. That is, the burst overlap timing required for the interferometric analysis was insufficient and it depends on the observation date. In this paper, we report the investigation results of this case and discuss the current status of the ALOS-2 ScanSAR InSAR. Some archives achieved before February 8, 2015 can be used for interferometric analysis with after Feb. 8. However, most of them have no interferometric pair. We also report that the archives acquired after February 8, have enough burst overlapping.

  6. DEM reconstruction of western mountain area based on InSAR technology%基于InSAR技术对西部高山地区DEM的重建

    Institute of Scientific and Technical Information of China (English)

    薛继群; 邓喀中; 范洪冬; 祝传广


    合成孔径雷达干涉测量技术是一种获取地面数字高程模型(DEM)的新技术.介绍利用InSAR获取DEM的基本流程,阐述相位解缠的理论方法以及基线估计中获取地面控制点的方法与原则,通过实验获取西部某高山地区的DEM,并与SRTM DEM作比较、分析,总结出其存在局限性的原因.%InSAR (Synthetic Aperture Radar Interferometry) is a new technology for achieving Digital Elevation Model (DEM). The paper introduces the basic flow of achieving DEM with InSAR technology and describes the theoretical method of phase unwrapping, at the same time the method and principle of obtaining ground control points among baseline evaluation processing are brought forward. Then, a DEM of the western mountain area was obtained, which also is compared and analyzed with SRTM-DEM. The reasons for their existence are summarized at last.

  7. Multidimensional High Spatiotemporal Resolution InSAR Time Series Assist Interdisciplinary Space- And Ground-Based Monitoring To Reveal Pre-Eruptive Signals At Nyamulagira Volcano (North Kivu, D.R.C.) (United States)

    d'Oreye, N.; Smets, B.; Kervyn, F.; Kervyn, M.; Albino, F.; Arellano, S. R.; Arjona, A. A.; Carn, S. A.; Fernandez, J.; Galle, B.; Gonzalez, P. J.; Head, E.; Pallero, J.; Prieto, J. F.; Samsonov, S. V.; Tedesco, D.; Tiampo, K. F.; Wauthier, C.


    Interdisciplinary space- and ground-based monitoring systems allowed the quantitative and detailed study of the Nyamulagira 2010 eruption (Congo). Field observations revealed the event as 4 eruptive phases delimited by major changes in effusive activity. Signals from ground deformation, seismicity, SO2 emission and thermal flux correlate with these eruptive phases. Moreover, MSBAS InSAR time series combining data acquired under different geometries and with different satellites (Samsonov and d'Oreye, 2012) allowed the detection of pre-, co- and inter-eruptive deformation in the Nyamulagira volcanic field. Using 8 years of ENVISAT, RADARSAT2 and ALOS data, the MSBAS method reveals the first unambiguous pre-eruptive ground deformations in the Virunga Volcanic Province. Precursory ground deformations are detected up to 3 weeks prior the onset of the 2010 eruption by images acquired by 3 different sensors in different geometries. These deformations took place in the main crater and along the SE flank of the volcano, where eruptive fractures will ultimately opened. Deformations coincide with small, though clear, increase of the short period seismicity and SO2 emissions.These seismic and SO2 variations alone were too small, however, to raise attention. The pre-eruptive ground deformation signals revealed by InSAR are of about the same amplitude and spatial extent as atmospheric noise and therefore cannot be identified on individual differential interferograms. Conventional time-series methods based on single acquisition geometry do not have a sufficient time resolution to discriminate such a precursory signal from an atmospheric artifact. The 3-week precursors detected at Nyamulagira contrast with the only precursory signal previously recognized so far in the Virunga, namely the increase of tremors and long period seismicity no more than few hours or days before the eruption onset. In January 2010, such short-term seismic precursors were detected less than two hours

  8. Analysis of Resolution of Bistatic SAR

    Institute of Scientific and Technical Information of China (English)


    In this paper, the spatial resolutions at different directions of bistatic synthetic aperture radar (BiSAR) have been derived from the ambiguity function. Compared with monostatic signal to noise ratio, BiSAR's resolutions of a fixed point target are varying with slow time since BiSAR system is space-variant. Constraints for the assumption of space-invariant bistatic topology are proposed in the paper. Moreover, under the assumption of invariance, the change of resolutions at different point in the image scene is taken into account, and we have specified two key parameters that affect resolutions directly and analyzed the way how they influence on the resolutions.

  9. Measurement of Subsidence in the Yangbajain Geothermal Fields from TerraSAR-X (United States)

    Li, Yongsheng; Zhang, Jingfa; Li, Zhenhong


    Yangbajain contains the largest geothermal energy power station in China. Geothermal explorations in Yangbajain first started in 1976, and two plants were subsequently built in 1981 and 1986. A large amount of geothermal fluids have been extracted since then, leading to considerable surface subsidence around the geothermal fields. In this paper, InSAR time series analysis is applied to map the subsidence of the Yangbajain geothermal fields during the period from December 2011 to November 2012 using 16 senses of TerraSAR-X stripmap SAR images. Due to its high resolution and short repeat cycle, TerraSAR-X provides detailed surface deformation information at the Yangbajain geothermal fields.

  10. Mapping ground surface deformation using temporarily coherent point SAR interferometry: Application to Los Angeles Basin (United States)

    Zhang, L.; Lu, Zhiming; Ding, X.; Jung, H.-S.; Feng, G.; Lee, C.-W.


    Multi-temporal interferometric synthetic aperture radar (InSAR) is an effective tool to detect long-term seismotectonic motions by reducing the atmospheric artifacts, thereby providing more precise deformation signal. The commonly used approaches such as persistent scatterer InSAR (PSInSAR) and small baseline subset (SBAS) algorithms need to resolve the phase ambiguities in interferogram stacks either by searching a predefined solution space or by sparse phase unwrapping methods; however the efficiency and the success of phase unwrapping cannot be guaranteed. We present here an alternative approach - temporarily coherent point (TCP) InSAR (TCPInSAR) - to estimate the long term deformation rate without the need of phase unwrapping. The proposed approach has a series of innovations including TCP identification, TCP network and TCP least squares estimator. We apply the proposed method to the Los Angeles Basin in southern California where structurally active faults are believed capable of generating damaging earthquakes. The analysis is based on 55 interferograms from 32 ERS-1/2 images acquired during Oct. 1995 and Dec. 2000. To evaluate the performance of TCPInSAR on a small set of observations, a test with half of interferometric pairs is also performed. The retrieved TCPInSAR measurements have been validated by a comparison with GPS observations from Southern California Integrated GPS Network. Our result presents a similar deformation pattern as shown in past InSAR studies but with a smaller average standard deviation (4.6. mm) compared with GPS observations, indicating that TCPInSAR is a promising alternative for efficiently mapping ground deformation even from a relatively smaller set of interferograms. ?? 2011.


    Directory of Open Access Journals (Sweden)

    J. W. Zhao


    Full Text Available As the received radar signal is the sum of signal contributions overlaid in one single pixel regardless of the travel path, the multipath effect should be seriously tackled as the multiple bounce returns are added to direct scatter echoes which leads to ghost scatters. Most of the existing solution towards the multipath is to recover the signal propagation path. To facilitate the signal propagation simulation process, plenty of aspects such as sensor parameters, the geometry of the objects (shape, location, orientation, mutual position between adjacent buildings and the physical parameters of the surface (roughness, correlation length, permittivitywhich determine the strength of radar signal backscattered to the SAR sensor should be given in previous. However, it's not practical to obtain the highly detailed object model in unfamiliar area by field survey as it's a laborious work and time-consuming. In this paper, SAR imaging simulation based on RaySAR is conducted at first aiming at basic understanding of multipath effects and for further comparison. Besides of the pre-imaging simulation, the product of the after-imaging, which refers to radar images is also taken into consideration. Both Cosmo-SkyMed ascending and descending SAR images of Lupu Bridge in Shanghai are used for the experiment. As a result, the reflectivity map and signal distribution map of different bounce level are simulated and validated by 3D real model. The statistic indexes such as the phase stability, mean amplitude, amplitude dispersion, coherence and mean-sigma ratio in case of layover are analyzed with combination of the RaySAR output.

  12. Tectonic evolution of the La González pull-apart basin in the Mérida Andes: combination of geological data and satellite radar interferometry (InSAR) (United States)

    Javadi, Hamid Reza; Dehghani, Maryam; Foroutan, Mohammad; Naeimi, Amir; Roustaei, Mahasa; Saidi, Abdollah; Urbina, Josef Angel


    The 500-km-long Boconó strike-slip fault runs as a major active fault along the backbone of the Mérida Andes fold-and-thrust belt. The recent right-lateral motion on the fault led to formation of numerous structures such as pull-apart basins which have formed in releasing bends and/or right-step offsets along the fault strands. The La González pull-apart is the biggest basin generated as an extensional strike-slip duplex in the central part of the fault. This duplex is made up of two strands of the Boconó fault as master/first-order faults, while normal right-lateral faults which formed during evolution of the basin are second-order faults. The extension of the basin is associated with seismic activities and surface offsets along the Boconó fault. InSAR investigations over a 31-month period also support active deformation within the basin. These data indicate that the La González basin is continuously being extended as a result of motion along the Boconó fault and formation of subsequent normal faults. In addition, the basin is being transversely shortened in NW-SE direction due to regional shortening across the Mérida Andes range followed by convergence between the Maracaibo microplate and the Guyana shield.

  13. Improved SAR Image Coregistration Using Pixel-Offset Series

    KAUST Repository

    Wang, Teng


    Synthetic aperture radar (SAR) image coregistration is a key procedure before interferometric SAR (InSAR) time-series analysis can be started. However, many geophysical data sets suffer from severe decorrelation problems due to a variety of reasons, making precise coregistration a nontrivial task. Here, we present a new strategy that uses a pixel-offset series of detected subimage patches dominated by point-like targets (PTs) to improve SAR image coregistrations. First, all potentially coherent image pairs are coregistered in a conventional way. In this step, we propose a coregistration quality index for each image to rank its relative “significance” within the data set and to select a reference image for the SAR data set. Then, a pixel-offset series of detected PTs is made from amplitude maps to improve the geometrical mapping functions. Finally, all images are resampled depending on the pixel offsets calculated from the updated geometrical mapping functions. We used images from a rural region near the North Anatolian Fault in eastern Turkey to test the proposed method, and clear coregistration improvements were found based on amplitude stability. This enhanced the fact that the coregistration strategy should therefore lead to improved InSAR time-series analysis results.

  14. Multi-temporal SAR data analysis for landcover, water-level changes, and subsidence studies in Southeastern Louisiana (United States)

    Kwoun, O.; Lu, Z.


    We used multi-temporal European Remote Sensing Satellites 1 and 2 (ERS-1/2), Environment Satellite (ENVISAT), and Canadian RADARSAT-1 Synthetic Aperture Radar (SAR) images for ecological, hydrological, and geological studies of the Southeastern Louisiana coastal flood zone. First, we present a distinctive correlation among the seasonal changes in SAR backscatter, interferometric coherence, and land cover types with the associated normalized difference vegetation indices. Second, we demonstrate the use of C-band SAR images to measure changes in the water-level beneath moderately dense swamp forests, at a vertical accuracy and spatial resolution that is not possible with the current gauge-based measurements. Finally, we apply the conventional SAR interferometry (InSAR) and the Permanent Scatterer InSAR techniques to map land surface subsidence in New Orleans and the surrounding area; the comparison of measured subsidence patterns shows certain discrepancies that are probably due to atmospheric delays in this humid area. Our study demonstrates the importance of SAR data for understanding this coastal flood zone and the associated ecological, hydrological, and geological processes.

  15. 基于模拟数据的极化干涉SAR成像研究%Study Polaremetric InSAR Imaging Base on Analogue Data

    Institute of Scientific and Technical Information of China (English)

    曾斌; 张晓玲; 黄顺吉



  16. Simulating pumping-induced regional land subsidence with the use of InSAR and field data in the Toluca Valley, Mexico (United States)

    Calderhead, A. I.; Therrien, R.; Rivera, A.; Martel, R.; Garfias, J.


    A multidisciplinary approach is presented here for quantifying land subsidence in a heavily pumped aquifer system with complex stratigraphy. The methodology consists in incorporating Terzaghi's 1D instantaneous compaction principle into a 3D groundwater flow model that is then applied and calibrated to reproduce observed hydraulic heads and compaction for the Toluca Valley, Mexico. Differential Interferometric Synthetic Aperture Radar (D-InSAR), a generated 3D-geological model, extensometers, monitoring wells, and available literature are used to constrain the model. The D-InSAR measured subsidence, extensometers, and numerical simulations of subsidence agree relatively well. Simulations show that since regional subsidence began in the mid 1960s there has been up to 2 m of subsidence in the industrial corridor, where heavy pumping and thick clay layers are found. This study shows that an approach using various sources of data is useful in estimating and constraining the vertical component of the inelastic skeletal specific storage.


    Institute of Scientific and Technical Information of China (English)

    Li Deren; Yang Jie


    The paper gives an overview of the principle and application of generating DEM from SAR, including the principle and processing flow of generating DEM from single SAR and SAR interferometry. Afterwards, the application fields of InSAR for terrain surveying, volcanic terrain surveying and D-InSAR for monitoring ground subsiding are listed and described as well.The problem and prospect of application are also pointed out in the last part of this paper.

  18. InSAR velocity field across the North Anatolian Fault (eastern Turkey): Implications for the loading and release of interseismic strain accumulation

    KAUST Repository

    Cakir, Ziyadin


    We use the Persistent Scatterer Interferometric Synthetic Aperture Radar (PS-InSAR) technique with the European Space Agency\\'s Envisat and ERS SAR data acquired on three neighboring descending tracks (T350, T078, and T307) to map the interseismic strain accumulation along a ~225 km long, NW-SE trending section of the North Anatolian Fault that ruptured during the 1939, 1942, and 1943 earthquakes in eastern Turkey. We derive a line-of-sight velocity map of the region with a high spatial resolution and accuracy which, together with the maps of earthquake surface ruptures, shed light on the style of continental deformation and the rela