Structural control on the kinematics of the deep-seated La Clapière landslide revealed by L-band InSAR observations

The objective of this work is to document the deformation pattern of the deep-seated La Clapière landslide for the period 2007–2010 from the combination of L-band synthetic aperture radar (SAR) interferograms, ground-based total station measurements and identification of the slope geomorphological structures. The interferograms are calculated for pairs of ALOS/PALSAR images at a time interval of 46 days. The displacement field derived from the interferograms reveals a non-uniform displacement gradient from the top (subsidence) to the bottom (accumulation). Vertical velocities are calculated from the unwrapped phase values and are in good agreement with ground-based measurements. The results demonstrate the potential of L-band ALOS/PALSAR imagery for the monitoring of active landslides characterized by complex kinematic patterns and by important changes in the soil surface backscattering in time.     

Analyzing Yengisogat Glacier surface velocities with ALOS PALSAR data feature tracking, Karakoram, China

Little is known about the detailed behavior of glaciers in the Karakoram Mountains. Advanced land observing satellite (ALOS) phased array type L-band synthetic aperture radar (PALSAR) data were used to obtain the surface velocity of the Yengisogat Glacier in the Karakoram Mountains. Four ALOS PALSAR data sets with 46?days temporal baseline acquired from 2007 to 2009 covered all four seasons and were used to extract the offset fields and estimate annual average surface velocity based on seasonal velocities. For the ALOS PALSAR data the synthetic aperture radar (SAR) feature-tracking procedures within the GAMMA software were utilized instead of SAR interferometry because of low coherence in case of fast-moving glaciers or large time intervals between the image acquisitions. The accuracy of the measurements is discussed, and the measurements were consistent with previous results from optical imagery feature tracking. It was revealed that the south tributaries contributed to the main flow of the glacier, with the glacier surface velocities of the south tributaries moving more rapidly than the north tributaries. This was mainly attributed to the effect of the glacier??s aspect in the glacier long-term development point of view. Seasonal and spatial variations of the glacier surface velocity imply that the tributary South Skamri Glacier is probably surging. This has previously been mentioned by some researchers such as Copland et al. The Equilibrium Line Altitude was found to be at about 5,000?m a.s.l for south tributaries, estimated from the surface velocity distribution along the glacier centerline.     

Investigating slow-moving landslides in the Zhouqu region of China using InSAR time series

In the Zhouqu region (Gansu, China), landslide distribution and activity exploits geological weaknesses in the fault-controlled belt of low-grade metamorphic rocks of the Bailong valley and severely impacts lives and livelihoods in this region. Landslides reactivated by the Wenchuan 2008 earthquake and debris flows triggered by rainfall, such as the 2010 Zhouqu debris flow, have caused more than 1700 casualties and estimated economic losses of some US$0.4 billion. Earthflows presently cover some 79% of the total landslide area and have exerted a strong influence on landscape dynamics and evolution in this region. In this study, we use multi-temporal Advanced Land Observing Satellite and Phased Array type L-band Synthetic Aperture Radar (ALOS PALSAR) data and time series interferometric synthetic aperture radar to investigate slow-moving landslides in a mountainous region with steep topography for the period December 2007–August 2010 using the Small Baseline Subsets (SBAS) technique. This enabled the identification of 11 active earthflows, 19 active landslides with deformation rates exceeding 100 mm/year and 20 new instabilities added into the pre-existing landslide inventory map. The activity of these earthflows and landslides exhibits seasonal variations and accelerated deformation following the Wenchuan earthquake. Time series analysis of the Suoertou earthflow reveals that seasonal velocity changes are characterized by comparatively rapid acceleration and gradual deceleration with distinct kinematic zones with different mean velocities, although velocity changes appear to occur synchronously along the landslide body over seasonal timescales. The observations suggest that the post-seismic effects (acceleration period) on landslide deformation last some 6–7 months.     

Monitoring Muztagh Kuksai glacier surface velocity with L-band SAR data in southwestern Xinjiang, China

This study presents the results of measuring surface velocity fields of alpine glaciers with multi-temporal ALOS/PALSAR synthetic aperture radar (SAR) data using the normalized cross-correlation technique. The main limitations of spaceborne optical data and interferometric SAR for retrieving reliable interferometric product are firstly discussed. Next, an efficient method of deriving surface velocity with spaceborne SAR system using the intensity-tracking method based on the cross-correlation optimization is expounded. This method is an invaluable alternative way of estimating the glacier surface field when the differential SAR interferometry is limited by the loss of coherence and can also overcome the drawback of the lack of available optical data in alpine glacier areas. The method was successfully applied in the region of the Muztagh Kuksai Glacier using ALOS/PALSAR L-band data with 44 days temporal separation. The glacier surface velocity fields were obtained for two different time intervals (14 January to 11 March 2009 and 1 September to 17 October 2009). The accuracy of the method was estimated from the residual value in the non-glacier area, which is often used to evaluate the performance of the approach for monitoring the glacier surface velocity. Finally the distribution maps of the surface velocity fields on the Muztagh Kuksai Glacier were retrieved with an accuracy of 0.3 m (SD 0.2 m) using L-band spaceborne SAR data. The results show that overall average velocity for 1 September to 17 October in 2009 is about 11 % faster than that for 14 January to 11 March in 2009. It is concluded that the potential of monitoring the long-term evolution of glaciers with SAR data should be emphasized.     

Monitoring subsidence at Messara basin using radar interferometry

The Messara valley is the largest and most productive region in the island of Crete, Greece. Over the last 20 years, extensive exploitation of the aquifer mainly for agricultural purposes has led to a 40-m decrease in the level of groundwater. This investigation aims at mapping ground subsidence that might be induced by such overpumping of groundwater using conventional differential interferometry. A total of 29 ERS-1 and 2 SAR and 7 ALOS PALSAR images have been used for forming interferograms. The images used cover the period from 1992 to 2000 and 2007 to 2010, respectively. Processing of ALOS L-band data (λ = 23.6 cm) has revealed a ground motion away from the Line of Sight of the satellite (LOS direction) that amounts to at least 3 cm/year for the period 2007–2010. Piezometric measurements and other geological parameters have also been analyzed.     

Detection and accuracy of landslide movement by InSAR analysis using PALSAR-2 data

Interferometric synthetic aperture radar (InSAR) analysis is a radar technique for generating large-area maps of ground deformation using differences in the phase of microwaves returning to a satellite. In recent years, high-resolution SAR sensors have been developed that enable small-scale slope deformation to be detected, such as the partial block movement of a landslide. The L-band SAR (PALSAR-2) is mounted on Advanced Land Observing Satellite-2 (ALOS-2), which was launched on 24 Mar. 2014. Its main improvements compared with ALOS are enhanced resolution of as high as 3 m with a high-frequency recurrence period (14 days). Owing to its high resolution and the use of the L-band, PALSAR-2 can obtain reflective data passing through a tree canopy surface, unlike the other synthetic aperture radars. Therefore, the coherence of InSAR in mountainous forest areas is less likely to decrease, making it advantageous for the extraction of slope movement. In this study, to verify the accuracy of InSAR analysis using PALSAR-2 data, we compared the results of InSAR analysis and the measurement of the displacement in a landslide by global navigation satellite system (GNSS) observation. It was found that the average difference between the displacements obtained by InSAR analysis and the field measurements by GNSS was only 15.1 mm in the slant range direction, indicating the high accuracy of InSAR analysis. Many of the areas detected by InSAR analysis corresponded to the locations of surface changes due to landslide activity. Additionally, in the areas detected by InSAR analysis using multiple datasets, the ground changes due to landslide movement were confirmed by site investigation.     

Extracting damages caused by the 2008 Ms 8.0 Wenchuan earthquake from SAR remote sensing data

Bad weather conditions usually limit the acquisition of optical remote sensing images, while all day and all weather synthetic aperture radar (SAR) shows the ability of providing timely remote sensing data for emergency response and rescue works after earthquake. Because SAR is sensitive to the surface changes caused by earthquake, the modified electromagnetic behaviour by geological disasters and the collapse of buildings can be recorded in SAR images as backscattering intensity changes. Absolute radiometric calibration was performed to SAR products to derive backscattering coefficient sigma nought from image digital number (DN). Based on change detection methods, Advanced Land Observing Satellite (ALOS) Phased Array type L-band Synthetic Aperture Radar (PALSAR) data and TerraSAR-X data acquired for the Ms 8.0 Wenchuan earthquake were used to extract earthquake damage information. This study revealed that landslides showed stronger backscattering and barrier lakes showed lower backscattering in post-earthquake 10 m ALOS PALSAR images comparing to pre-earthquake, and collapsed buildings showed lower backscattering compared to un-collapsed buildings in 1 m TerraSAR-X image. Results showed that SAR data with different spatial resolutions are useful for different earthquake damage information extraction: medium spatial resolution SAR data, e.g. 10 m ALOS PALSAR data, were efficient for secondary geological disaster extraction; high-resolution SAR data, e.g. 1 m TerraSAR-X data, with the help of ancillary GIS data or high-resolution optical data, could be used to extract building collapse information in urban areas. This study indicates that SAR remote sensing data can provide earthquake damage information at early emergency stage and assist the field surveying, further damage assessment and post-earthquake reconstruction.     

Testing the potential of Sentinel-1A TOPS interferometry for the detection and monitoring of landslides at local scale (Veneto Region,Italy)

The recent Sentinel-1 mission, started by the European Space Agency in April 2014, provides the scientific community with new capabilities for the monitoring of the Earth surface. In particular, the Terrain Observation by Progressive Scans imaging technique used in the Interferometric Wide swath acquisition mode permits to acquire data over very wide areas (250 km of swath extension) at 20-m spatial resolution, with 12-day revisit time, making it suitable for ground displacement monitoring applications. With more than 1 year of synthetic aperture radar images available, it is now possible to carry out monitoring activities of slow moving phenomena such as landslides at both regional and local scales. In this work, the potential of Sentinel-1A for the monitoring of shallow (from 2 to 6 m of depth) landslides occurring in the North-Eastern Italian Pre-Alps was tested. Two stacks of Sentinel-1A scenes acquired in both ascending and descending orbits were processed using the Permanent Scatterer Interferometry (PSI) technique. The results, analysed in terms of PS density and quality, were compared with the ERS-1/2 and ENVISAT PSI database available from the Italian National Cartographic Portal to assess the capabilities of Sentinel-1A in detecting and monitoring landslides in respect to the previous satellite missions. The results of this work show the great potential of Sentinel-1A in the continuous monitoring of landslide-prone territories even at local scale. The achievable results can provide information that is useful to delineate the spatial and temporal evolution of landslides and precisely assess their rates of deformation.     

Mapping of slow landslides on the Palos Verdes Peninsula using the California landslide inventory and persistent scatterer interferometry

Extremely slow landslides, those with a displacement rate <16 mm/year, may be imperceptible without proper instrumentation. These landslides can cause infrastructure damage on a long-term timescale. The objective is to identify these landslides through the combination of information from the California landslide inventory (CLI) and ground displacement rates using results from persistent scatterer interferometry (PSI), an interferometric synthetic aperture radar (InSAR) stacking technique, across the Palos Verdes Peninsula in California. A total of 34 ENVISAT radar images (acquired between 2005 and 2010) and 40 COSMO-SkyMed radar images (acquired between 2012 and 2014) were processed. An InSAR landslide inventory (ILI) is created using four criteria: minimum PS count, average measured ground velocity, slope angle, and slope aspect. The ILI is divided into four categories: long-term slides (LTSs), potentially active slides (PASs), relatively stable slopes (RSSs), and unmapped extremely slow slides (UESSs). These categories are based on whether landslides were previously mapped on that slope (in the CLI), if persistent scatterers (PSs) are present, and whether PSs are unstable or stable. The final inventory includes 263 mapped landslides across the peninsula, of them 67 landslides were identified as UESS. Although UESS exhibit low velocity and are relatively small (average area of 8865 m² per slide), their presence in a highly populated area such as the Palos Verdes Peninsula could lead to destruction of infrastructure and property over the long term.     

PALSAR及RADARSAT2全极化雷达数据在地质构造应用中的研究

由于雷达数据不受天气影响,且具有一定的穿透能力,近年来已被广泛的运用在地质构造信息提取研究中。ALOS PALSAR与RADARSAT2是近年发展的最先进的雷达传感器,其全极化模式同时又具有较高的空间分辨率,这为植被区地质构造研究提供了良好的数据源。本文选取非洲埃塞俄比亚西部为研究区,通过对研究区域两种全极化雷达数据进...     

应用SAR特征匹配方法估计音苏盖提冰川表面流速

喀喇昆仑山区冰川因位于高海拔地区且远离人类正常活动的区域,使得连续的表面流速的地面观测很难实施,因此,对该区域冰川运动机理研究相对比较少.采用日本高级陆地观测卫星携带的相控阵型 L 波段合成孔径雷达(Advanced Land Observing Satellite,Phase Array L-band Synthet...     

时序InSAR技术三峡库区藕塘滑坡稳定性监测与状态更新

坡体表面形变是表征坡体稳定性的重要信息,因此,非常有必要对滑坡多发区域进行时序常规变形监测.近年来,星载合成孔径雷达数据由于其覆盖范围大、形变监测精度高的特点,被越来越多的用于山区滑坡识别与探测.首先介绍了联合分布式目标与点目标的时序InSAR方法,并将该方法应用于分析覆盖三峡藕塘滑坡的2007年至2011年的19景ALOS PALSAR数据和2015年至2018年的47景Sentinel-1数据,提取了数据覆盖时间段内的藕塘地区的变形速率.发现相比于2007年至2011年,2015年至2018年新增三处不稳定斜坡.进一步对滑坡的时序变形分析表明,降雨和水位变化是坡体稳定性最大的两个影响因素.实验证明时序InSAR方法可以作为常规形变手段来识别与监测三峡库区等地区潜在的滑坡,为防灾减灾提供支持与依据.      

Survey and monitoring of landslide displacements by means of L-band satellite SAR interferometry

This paper illustrates the capabilities of L-band satellite SAR interferometry for the investigation of landslide displacements. SAR data acquired by the L-band JERS satellite over the Italian and Swiss Alps have been analyzed together with C-band ERS-1/2 SAR data and in situ information. The use of L-band SAR data with a wavelength larger than the usual C-band, generally considered for ground motion measurements, reduces some of the limitations of differential SAR interferometry, in particular, signal decorrelation induced by vegetation cover and rapid displacements. The sites of the Alta Val Badia region in South Tyrol (Italy), Ruinon in Lombardia (Italy), Saas Grund in Valais (Switzerland) and Campo Vallemaggia in Ticino (Switzerland), representing a comprehensive set of different mass wasting phenomena in various environments, are considered. The landslides in the Alta Val Badia region are good examples for presenting the improved performance of L-band in comparison to C-band for vegetated areas, in particular concerning open forest. The landslides of Ruinon, Saas Grund, and Campo Vallemaggia demonstrate the strength of L-band in observing moderately fast displacements in comparison to C-band. This work, performed with historical SAR data from a satellite which operated until 1998, demonstrates the capabilities of future planned L-band SAR missions, like ALOS and TerraSAR-L, for landslide studies.     

基于SBAS InSAR的鲜水河断裂带蠕滑型滑坡特征研究

鲜水河断裂带是青藏高原东部川滇地块的一条重要边界断裂,全新世以来活动强烈,断裂带沿线岩土体结构破碎强烈,在断裂活动诱发地震、断裂蠕滑和强降雨等因素作用下,断裂带沿线滑坡、泥石流等地质灾害发育密度大,危害严重。在前人研究的基础上,采用短基线集(SBAS InSAR)的方法,基于日本对地观测卫星(ALOS 1)所获得的2007—2011年期间15景PALSAR数据,对鲜水河断裂带道孚至炉霍段的活动速率进行分析计算,获取了该段断裂带内蠕滑型滑坡5年间的时间序列形变特征。研究结果表明：鲜水河断裂带道孚至炉霍段近年来以蠕滑滑动为主,蠕滑速率为(94±078) mm/a,断裂的蠕滑作用对区域构造应力场和断裂带内滑坡具有重要的控制作用,表现为距离鲜水河断裂带越近,影像间相干性越强,稳定的相干点越多,干涉效果越好,滑坡滑动累计位移越大。沿鲜水河断裂道孚至炉霍段,共识别出98个蠕滑型滑坡,沿鲜水河断裂带两侧呈线性展布,并分析了典型蠕滑型滑坡的地表形变特征。基于SBAS InSAR的雷达数据处理方法,可以有效地分析地表的缓慢变形以及区域性蠕滑型滑坡的发育发展变化规律,研究结果对于鲜水河断裂带沿线防灾减灾及类似构造活动地区的地质灾害研究具有一定的指导作用。     

How to assess landslide activity and intensity with Persistent Scatterer Interferometry (PSI): the PSI-based matrix approach

We provide a step-by-step analysis and discussion of the ‘PSI-based matrix approach’, a methodology employing ground deformation velocities derived through Persistent Scatterer Interferometry (PSI) for the assessment of the state of activity and intensity of extremely to very slow landslides. Two matrices based on PSI data are designed respectively for landslides already mapped in preexisting inventories and for newly identified phenomena. Conversely, a unique intensity scale is proposed indiscriminately for both. Major influencing factors of the approach are brought to light by the application in the 14 km² area of Verbicaro, in Northern Calabria (Italy). These include lack of PSI data within the landslide boundaries, temporal coverage of the available estimates, and need of field checks as well as the operative procedures to set the activity and intensity thresholds. For the area of Verbicaro, we exploit 1992–2011 PSI data from ERS1/2 and RADARSAT1/2 satellites, projecting them along the maximum slope directions. An activity threshold of ±5 mm/year is determined by applying the average projection factor of local slopes to the PSI data precision. The intensity threshold between extremely and very slow phenomena (16 mm/year) is reduced by ~20 % to account for temporal and spatial averages being applied to attribute representative velocities to each landslide. The methodology allows assessing the state of activity and the intensity for 13 of the 24 landslides premapped in the 2007 inventory and for two newly identified phenomena. Current limitations due to characteristics and spatial coverage of PSI data are critically tackled within the discussion, jointly with respective implications.     

Investigating landslides with space-borne Synthetic Aperture Radar (SAR) interferometry

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

Complementing geotechnical slope stability and land movement analysis using satellite DInSAR

This paper explores the potential of using satellite radar inteferometry to monitor time-varying land movement prior to any visible tension crack signs. The idea was developed during dedicated geotechnical studies at a large open-pit lignite mine, where large slope movements (10–20 mm/day) were monitored and large fissures were observed in the immediate area outside the current pit limits. In this work, differential interferometry (DInSAR), using Synthetic Aperture Radar (SAR) ALOS images, was applied to monitor the progression of land movement that could potentially thwart mine operations. Early signs of land movements were captured by this technique well before their visual observation. Moreover, a qualitative comparison of DInSAR and ground geodetic measurements indicates that the technique can be used for the identification of high risk areas and, subsequently, for the optimization of the spatial distribution of the available ground monitoring equipment. Finally, quantitative land movement results from DInSAR are shown to be in accordance with simultaneous measurements obtained by ground means.     

Combining field data with infrared thermography and DInSAR surveys to evaluate the activity of landslides: the case study of Randazzo Landslide (NE Sicily)

Infrared thermography and DInSAR surveying methodologies have been integrated and compared to study the state and distribution of activity of one of the largest landslides of northeastern Sicily, Italy, which is characterized by a slow retrogressive evolution. The Randazzo Landslide was triggered by heavy rainfalls in 1996 and its activity caused the disruption of a strategic transportation corridor, along with the formation of a landslide dam in the Alcantara Valley. After more than 20 years, the slope is still affected by instability and worrying signs of reactivations (e.g., deformation and cracking of road pavement) were surveyed in the field. The application of infrared thermography during the landslide survey allowed detecting peculiar features according to the different thermal pattern of the elements occurring along the slope. In particular, areas with different surface temperature were associated to vegetated spots, steep portions, bare sectors, and contact between different lithologies. Incipient portions and ancient landslide bodies were located, proving the utility of this experimental approach to the surveying of unstable slopes. Information on the entity, in terms of velocity, of the recent landslide displacements were provided by a DInSAR monitoring, which allowed ascertaining the presence of movements affecting several sectors of the landslide, mainly matching with the areas highlighted by thermal images. Achieved outcomes represent a scientifically relevant datum providing important information on the surveyed landslide from the risk management point of view and proving the utility of integrating infrared thermography and DInSAR methodologies for the study of complex movements.     

Coastal lateral spreading in the world heritage site of the Tramuntana Range (Majorca,Spain). The use of PSInSAR monitoring to identify vulnerability

The Bàlitx area is located on the steep coastal side of the Tramuntana Range (Majorca), a mountainous region which was declared a World Heritage Site by UNESCO in 2011 in the cultural landscape category. The Bàlitx site was occupied by farming areas with dry stone constructions and water storing systems of both Roman and Islamic origin. The coastal landscape is characterised by a large fault escarpment of up to 260 m in height. Lateral spreading processes are favoured by local stratigraphy and tectonics in an energetic coastal dynamics scenario. Block spreading morphologies are identified along the escarpment, with large, rocky blocks of volumes up to 60?×?10³ m³ moving very slowly until their collapse. Consequently, a thick and highly karstified breccia deposit is accumulated at the base of the scarp. The lowest, oldest breccia outcrop has been dated (Th/U), and an age of 82.5?±?5.6 kyr was obtained, reflecting the time span this process has been active. Additionally, numerous geomorphological slope features are identified in the area: landslides, rockfalls, and, more specifically, long and deep cracks in the hanging wall block of the fault, which also reveal active lateral spreading processes. Coastal dynamics have been investigated by interpreting offshore geophysical studies, bathymetry data and borehole information to determine the role of wave energy in the stability of the slope. Additionally, 14 SAR images from the ALOS PALSAR satellite have been exploited for the present work, covering a period spanning from 2007 to 2010, an anomalous rainy period in the region. Images were processed using the Persistent Scattered Interferometry (PSI) technique. PSInSAR results reveal that the rate of movement for the Bàlitx lateral spreading is extremely low (??5.2 mm/year on average), but major activity has been detected in the NE sector, where velocity rates can reach values of up to ??16 mm/year Coastal dynamics in the area can explain this, as a small island generates wave refraction and reflection determining more intense erosive processes in the NE part, which lead to a greater destabilising effect on the slopes. A simple vulnerability approach has been developed to take the elements of cultural heritage into account. Vulnerability increases from SW to NE, in accordance with landslide activity. The Bàlitx case study could provide a testimony to the effects of mass movements and coastal dynamics in an exceptional example of Mediterranean agricultural landscape.     

利用雷达差分干涉测量技术获取汶川MS 8.0地震形变场

利用ENVISAT/ASAR和ALOS/PALSAR数据,结合两路差分干涉测量技术获得了汶川地震的同震形变信息和震前、震后地面在卫星视线(light of sight,简称LOS)方向上的形变特征。结果表明,汶川地震引起的地面形变范围广,程度大,地震形变沿断层向北北东向扩展,所形成的差分干涉条纹明显。地面的形变特征对于推断断层的性质,研究地震形变和地震发育特征具有重要的参考价值。另外,将同震雷达差分干涉测量的结果与利用USGS发布的汶川地震有限元断层模型(finite fault model)反演的LOS方向的形变进行了对比验证,发现二者在断裂带的上盘具有较好的一致性,但在下盘却有较大的误差。通过不同传感器干涉结果的对比发现,L波段的雷达干涉结果更能够反映汶川大地震在龙门山断裂带附近的地面形变信息。