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1.
Post-event Interferometric Synthetic Aperture Radar (InSAR) analysis on a stack of 45 C-band SAR images acquired by the ESA Sentinel-1 satellites from 9 October 2014 to 19 June 2017 allowed the identification of a clear precursory deformation signal for the Maoxian landslide (Mao County, Sichuan Province, China). The landslide occurred in the early morning of 24 June 2017 and killed more than 100 people in the village of Xinmo. Sentinel-1 images have been processed through an advanced multi-interferogram analysis capable of maximising the density of measurement points, generating ground deformation maps and displacement time series for an area of 460 km2 straddling the Minjiang River and the Songping Gully. InSAR data clearly show the precursors of the slope failure in the source area of the Maoxian landslide, with a maximum displacement rate detected of 27 mm/year along the line of sight of the satellite. Deformation time series of measurement points identified within the main scarp of the landslide exhibit an acceleration starting from April 2017. A detailed time series analysis leads to the classification of different deformation behaviours. The Fukuzono method for forecasting the time of failure appear to be applicable to the displacement data exhibiting progressive acceleration. Results suggest that satellite radar data, systematically acquired over large areas with short revisiting time, could be used not only as a tool for mapping unstable areas, but also for landslide monitoring, at least for some typologies of sliding phenomena.  相似文献   

2.
The Xinmo landslide occurred in the early morning of 24 June 2017 at about 5:38 am local time. This catastrophic event caused enormous casualties and huge economic losses in Xinmo Village, Mao County, Sichuan Province, China. In this study, Synthetic Aperture Radar (SAR) datasets acquired by X-band TerraSAR-X, Phased Array type L-band Synthetic Aperture Radar-2 (PALSAR-2) aboard the Advanced Land Observing Satellite-2 (ALOS-2), and C-band Sentinel-1 over the disaster area were collected and analyzed to characterize this landslide. The high-resolution TerraSAR-X intensity images were used to evaluate the landslide disaster and delineate the sliding area. Afterwards, two ALOS-2 PALSAR-2 image pairs and a stack of 45 Sentinel-1 images were processed to detect precursory movements of the landslide surface, using the conventional differential InSAR (DInSAR) method and advanced time series InSAR analysis. The unstable source area near the ridge was identified from the displacement rate map derived from Sentinel-1 datasets. The maximum displacement rate detected at the source area was ?35mm/year along the radar line of sight (LOS) direction. The time series of LOS displacements over 2 years presents an easily discerned seasonal evolution pattern. In particular, a sudden acceleration of the displacement, dozens of days before the collapse was clearly captured by the Sentinel-1 observations, which might suggest that early warning of landslide disasters is possible given the availability of operational SAR data acquired in frequent repeat-pass mode, such as the Sentinel-1 twin-satellite constellation.  相似文献   

3.
金沙江缝合带是滑坡灾害的高发区,且具有较大的堵江威胁。以堵江风险较高的色拉滑坡为研究对象,选取高时间分辨率的升降轨Sentinel-1A/B数据,利用MSBAS InSAR技术对该滑坡展开地表形变监测研究。文章在利用不同轨道的Sentinel-1A/B获取色拉滑坡2018—2020年间的二维动态形变时间序列的基础上,分析了典型特征点形变时间序列特征。结果表明,在2018年1月—2020年4月色拉滑坡东西向累积形变最高达到165 mm,垂直向累积形变达?102 mm,滑坡体形变加速的时间点被成功地捕获。最后,分析了该滑坡的形变趋势,通过现场调查结果验证了所获得滑坡监测结果的准确性。  相似文献   

4.
史绪国  徐金虎  蒋厚军  张路  廖明生 《地球科学》2019,44(12):4284-4292
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.   相似文献   

5.
基于TerraSAR-X强度图像相关法测量三峡树坪滑坡时空形变   总被引:3,自引:1,他引:2  
三峡工程蓄水之后,有可能引起两岸滑坡的发生.本文以三峡库区树坪为研究区域,对不同时相的TerraSAR-X的强度图进行相关计算,求解出2009年2月至2009年10月期间发生的滑坡位移场时空演化.结果表明,在滑坡发生的前几个月,累积变形量很小;在滑坡发生的两三个月当中,变形量比较大,平均位移达到51cm;之后的几个月中,变形量又恢复到平静期的数值,与布设在该区的位移伸缩计结果一致.从本文的研究可以看出,该方法不仅能计算出滑坡引起的形变场,而且能探测地面形变的早期信号,可以用它作为三峡库区未来滑坡监测的重要技术手段.  相似文献   

6.
Sentinel卫星凭借其超高的辐射分辨率、稳定的轨道系统、较大的覆盖能力、较短的重返时间、可免费下载的数据,在斜坡灾害识别监测方向上有广泛的应用。自1963年意大利瓦伊昂特大滑坡发生以来,岸坡地质灾害一直是峡谷区水库关注的主要问题之一。以金沙江上游溪洛渡水库区为例,结合PALSAR-2、TerraSAR-X数据,评价Sentinel-1 SAR数据在西南山区水库变形斜坡InSAR监测中的适用性,以理论结合实际结果分析Sentinel-1数据是否可以在一定条件下替代其他商业数据,为今后相关行业应用提供参考。结果显示:Sentinel-1数据在研究区可解译的变形斜坡约200处,类型有滑坡、危岩体和塌岸;经现场核查,Sentinel-1数据解译的最小变形斜坡投影面积约为2400 m2,约35 m(长)×77 m(宽)大小,共16个变形像元聚集。高山峡谷区叠掩、阴影现象严重,通过对雷达常用观测模式下的SAR数据的比较,在SAR数据交集区域,有效观测面积为Sentinel-1升轨70.3%,Sentinel-1降轨68.9%,PALSAR-2升轨70.4%,PALSAR-2降轨67.6%,TerraSAR-X降轨52.5%,在不考虑分辨率的情况下,在库区Sentinel-1数据与其他两种SAR数据观测能力相比持平或更优秀。6月至11月初是溪洛渡水库的水位上升期,周边植被发育较好,造成数据相干性较差,2017年后Sentinel-1A(1B)双星拍摄获取的SAR数据量增加,高频观测可使相干性提高,利用2017年后该卫星数据可有效识别水库蓄—排水周期内的区域性变形斜坡发育变化情况。当长时间缺失SAR数据时,会造成最近一对SAR数据间的某些像元测量的变形超过其InSAR最大量程,解缠时丢失相位周期。Sentinel-1数据由于连续性较好,监测斜坡的变形趋势较为连续,因此更适合连续小变形的趋势识别。   相似文献   

7.
金沙江结合带由于地质构造发育,地震活动频繁,河谷切割强烈,岸坡高陡狭窄, 岩体极为破碎,历史上发生过多起大型滑坡堵江事件。以白格滑坡两次堵江事件(2018年10月11日、2018年11月3日)为例,采用2009年12月4日至2020年10月16日多期、多源卫星遥感数据源,通过遥感判识、对比分析等方法对滑坡体滑前斜坡变形特征、滑后滑坡堆积特征、滑后斜坡残留体变形特征进行特大型堵江滑坡链式特征遥感动态分析。根据多期遥感影像,将白格滑坡变形特征划分为早期滑动变形阶段(2009—2011年)、稳定变形阶段(2011—2015年)、快速变形阶段(2015—2017年)、剧烈变形阶段(2017—2018年)、变形破坏阶段(2018年以后)等5个阶段。根据滑坡第一次滑后的变形破坏特征,将滑坡划分为滑源区、铲刮区、堆积区以及拉裂变形区。根据滑坡第二次滑后的变形破坏特征,将滑坡划分为二次滑坡滑源区、二次滑坡堆积区(堰塞体)、二次铲刮(堆积)区、二次铲刮区影响区以及拉裂变形区。基于上述研究成果,对白格滑坡灾害链式特征进行总结分析,为金沙江结合带高位远程滑坡灾害链式特征研究提供参考。  相似文献   

8.
单一平台或轨道的InSAR(Interferometric Synthetic Aperture Radar,InSAR)技术通常只能获取到滑坡体沿雷达卫星视线(LOS)方向的一维形变信息,无法直接获取到滑坡体沿坡向的形变信息,使得InSAR技术无法充分满足滑坡监测的工程需求。针对这一问题,本文提出联合升降轨Sentinel-1A数据提取滑坡沿坡向形变速度场的模型算法,其基本方法是:首先利用InSAR技术分别获取升轨和降轨沿LOS方向的形变速度场,然后根据坡向和坡度建立滑坡的滑动面坐标系,基于LOS方向与滑动面的几何关系对升降轨对应的LOS向形变速度值进行建模,在滑动面上不存在法线方向形变的合理假设下通过解算独立方程组获得滑坡体沿坡向的形变速度场和沿垂直坡向的形变速度场。本文选取四川省理县桃坪乡古滑坡作为研究对象,并通过模拟实验对模型的解算精度进行验证,结果表明:相比于LOS向形变速度场,重建的沿坡向和沿垂直坡向形变速度场更加清晰地揭露了滑坡体的主要位移模式和危险性较高的坡体区域。同时,模拟实验结果表明,模型算法的解算误差与噪声水平大致呈线性增加的关系,当噪声水平达到10 mm·a-1时,沿坡向形变速度场的解算误差为14.1 mm·a-1,沿垂直坡向形变速度场的解算误差为11.9 mm·a-1,证明了模型算法以及结果的可靠性。  相似文献   

9.
库岸潜在滑坡变形分析是保障国家水利水电设施安全运行的重要环节,针对仅利用单一轨道SAR数据对库岸潜在滑坡变形监测不准确的问题,采用SBAS-InSAR技术,联合升降轨Sentinel-1 SAR数据构建研究区2019年7月至2021年7月的雷达视线方向形变时间序列,并结合无人机野外调查,分析白鹤滩水电站库岸典型潜在滑坡...  相似文献   

10.
Slope instability arisen along with dam construction is a common problem of great concern in reservoir areas. Thus, displacement monitoring of active slopes is of great importance for the safety of dam operation. The unstable Guobu slope is located only about 1.5 km away from Laxiwa hydropower station in upstream Yellow River. In this study, Synthetic Aperture Radar (SAR) datasets acquired by C-band Environmental Satellite (ENVISAT) Advanced Synthetic Aperture Radar (ASAR), L-band Advanced Land Observing Satellite 2 (ALOS-2) Phased Array type L-band Synthetic Aperture Radar 2 (PALSAR-2), and X-band TerraSAR-X covering different evolution stages of Guobu slope were collected to investigate the displacement history so as to facilitate understanding of its deformation and failure mechanisms. The displacements occurred during the past decade were quantitatively identified for the first time by SAR pixel offset tracking analyses. The results show that before the reservoir impoundment, the maximum accumulative displacements on the slope were more than 7 m from 2003 to 2008, while the post-impoundment displacements also exceeded 7 m in just 1 year from September 2009 to September 2010. Furthermore, this slope is still in active deformation up to now. Nevertheless, the displacement rates seem decreased recently according to the interferometric results of TerraSAR-X data pairs from September 2015 to March 2016.  相似文献   

11.
Active microwave has a huge potential in the estimation of soil moisture especially over large areas where the meteorological observations are seldom. The large contrast in dielectric constant between different types of soil is considered as the main factor for measuring the moisture content. This study is aimed at the extraction of soil moisture over the areas of Bukit Antarabangsa, Malaysia using active microwave remote sensing technique in order to examine the impact of moisture content dynamically on landslides occurrence, which have been a basic challenge that threaten Bukit Antarabangsa area, particularly in falling of monsoon seasons. This study addressed a specific event that took place in 6 December 2008 due to a very high level of precipitation that resulted in a raise in ground water table causing the occurrence of landslide. One Radarsat-1 image acquired in July 2008 before the landslide was used for generating the moisture content map. The resultant moisture content map showed a reasonable distribution of the moisture concentrated over the forest areas which has previous records landslides. Moreover, it was found that the previous landslide events were within the high moisture zone indicating the presence of high moisture content. Subsequently, three moisture maps were extracted from Landsat-7 ETM+, which were then used for validation process. A statistically based validation technique was used by calculating area under the curve that correlates the high moisture values of three images. In order to validate the Landsat-7 ETM+ moisture content, monthly rainfall data was plotted against the high moisture values derived from three Landsat-7 images. The validation result indicated an acceptable compatibility. The spatial relation between high moisture areas in Landsat-7 ETM+ images along the year resulted in a good fitting in the high–low moisture distribution areas with sensitivity ranged of 60–70 %. Finally, the moisture content map generated by Radarsat-1 was validated using a landslide inventory map. The resultant validation produced an area under curve of 0.704 (70 %).  相似文献   

12.
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.  相似文献   

13.
On 15 February 2010, a landslide of great dimensions occurred at Maierato (Calabria, Southern Italy) after a long rainy period. Although the zone was continuously affected by ground movements especially during the wet seasons, no monitoring system was installed before the occurrence of the landslide. However, many photos and two videos were taken during the failure process of the slope. In the present study, the available images are used to reconstruct the kinematics of the landslide. In addition, a finite element analysis is performed to define the main factors of triggering and to interpret the failure mechanism of the slope. This analysis is also based on the data from a site investigation carried out after the landslide to characterise the involved soils from a geotechnical viewpoint. The analysis also accounts for the strain-softening behaviour of some soils. The results have shown that the Maierato landslide was the reactivation of a pre-existing landslide body, which was caused by a significant increase in groundwater level.  相似文献   

14.
This study analyzes the mechanism of the landslide event at Hsiaolin Village during Typhoon Morakot in 2009. This landslide event resulted in 400 deaths. The extremely high intensity and accumulative rainfall events may cause large-scale and complex landslide disasters. To study and understand a landslide event, a combination of field investigations and numerical models is used. The landslide area is determined by comparing topographic information from before and after the event. Physiographic parameters are determined from field investigations. These parameters are applied to a numerical model to simulate the landslide process. Due to the high intensity of the rainfall event, 1,675 mm during the 80 h before the landslide event, the water content of soil was rapidly increased causing a landslide to occur. According to the survivors, the total duration of the landslide run out was less than 3 min. Simulation results indicated that the total duration was about 150 s. After the landslide occurrence, the landslide mass separated into two parts by a spur at EL 590 in about 30 to 50 s. One part passed the spur in about 30 to 60 s. One part inundated the Hsiaolin Village and the other deposited at a local river channel and formed a landslide dam. The landslide dam had height between 50 and 60 m and length between 800 and 900 m. The simulation result shows that the proposed model can be used to evaluate the potential areas of landslides induced by extremely high intensity rainfall events.  相似文献   

15.
章彭  刘文明 《贵州地质》2020,37(1):94-97
InSAR技术是当前从卫星雷达遥感获取的对地观测数据中提取地形信息最主要的技术手段。本文以贵州省普安县罗马山为研究区,收集了2017年4月16日至2018年8月5日共10景ALOS PALSAR2数据,生成9个干涉对,以形变时间序列的方式对研究区中的滑坡体进行形变监测分析。同时,收集兴仁县2017年4月至2018年8月降雨量信息,通过与形变时间序列的对比分析,可发现降雨量与形变的高度相关性,这对滑坡灾害的预防具有重要意义。  相似文献   

16.
受气候暖湿化和冻融作用的影响,近年来西藏东部地区的山体滑坡多发频发,对人民生命财产安全造成严重威胁,制约了当地经济社会发展,因此,迫切需要利用有效手段对滑坡灾害隐患开展大范围调查与早期识别。以藏东317国道矮拉山地区为例,利用小基线集时序InSAR(Interferometric Synthetic Aperture Radar)技术,分别对2017年3月—2019年7月期间Sentinel-1A SAR升、降轨数据集进行地表形变监测分析,获取了该地区滑坡体隐患的分布情况,并讨论了滑坡历史形变演化特征及成因。结果表明:大部分区域较为稳定,滑坡隐患主要集中在山谷两侧,升降轨InSAR提高了滑坡监测识别的准确性和覆盖度;冻融滑坡形变过程与降雨型滑坡存在差异,呈现平稳期和失稳期交替出现的季节性变化特征;形变过程主要受冻融和降雨影响,两者共同作用加速坡体变形。实验结果验证了InSAR技术能够有效弥补传统监测手段的不足,可在高山冻土区滑坡隐患早期识别与监测防治中发挥重要作用。  相似文献   

17.
Ground-based SAR interferometry for monitoring mass movements   总被引:11,自引:3,他引:8  
An innovative technique for the remote assessment of ground displacements, based on radar interferometry and implemented using ground-based instrumentation (GB-InSAR), has been tested in recent years on a number of selected case sites. The system, known as LISA, developed by the Joint Research Centre (JRC) of the European Commission, is a ground-based radar interferometer specifically designed for field use. It is composed of two radar antennas mounted on a linear rail which horizontally slides to form a synthetic aperture. Coherent SAR processing converts the raw data into an image containing, for each pixel, information on the wave phase, which depends on the target-sensor distance. Consecutive couples of SAR images can be cross-correlated to form interferograms representing phase variations which can be directly related to ground displacement along the sight-line of the radar system, since they are acquired from exactly the same position. Several applications of the system have been conducted on a number of mass movements located in Italy, in order to validate the technique for the monitoring of landslides. GB-InSAR has proved its potential for the measurement of the superficial ground displacements of different landslide types, in terms of failure mechanism, materials involved, kinematics, water content and deformation rates. In particular conditions, such as fast-moving phenomena and inaccessible areas, the technique can be employed directly as a monitoring tool, providing multi-temporal displacement maps of the observed area. Additionally, some applications of the GB-InSAR have provided a fundamental support to decision makers during landslide emergencies, allowing the civil protection authorities to assess the risk and to manage an effective emergency response.  相似文献   

18.
Landslides are a form of geological disaster. Landslide development around the Three Gorges Dam is affected by many factors, such as the dam’s water storage cycle, flood discharge and precipitation. In this work, we investigated the Woshaxi landslide in Zigui County, Hubei Province. We gathered landslide images from April to May 2015, using digital cameras to observe the landslide surface. The landslide images were analyzed with a digital correlation method to obtain a landslide deformation field. The overall displacement was distributed non-uniformly, with displacements of up to 50 cm. We found landslide movement is a non-uniform and non-rigid body motion. By integrating the speckle method, grayscale feature search and other related methods, we not only succeeded in dealing with landslide data at various scales and levels, but also solved problems such as the registration of collected images and peering of gray levels. We calculated the displacement variation and direction of all landslide points and obtained the landslide displacement distribution. The method’s indoor calibration test error was within an acceptable range. This method is a good candidate for landscape monitoring due to its convenient operation, low cost and ability to extract useful information from a huge amount of data.  相似文献   

19.
On June 24, 2017 (21:39 UTC, June 23rd), a catastrophic landslide occurred at Xinmo village of Mao County, Sichuan Province, China. Soon after the event, some research teams carried out field investigations in order to both support the emergency operations and to understand the failure mechanism and possible evolutionary scenarios. Based on further in-depth interpretation of high-resolution remote-sensing images and detailed field surveys, it is newly found that there are at least six old rockfall deposits in the source area that prove the historic activity of the landslide scarp. Seismic data of the event and morphological evidences along the slope indicate that the landslide was preceded by a significant rockfall. Mechanical calculations show that the surface force due to pore water was far less than the impact force due to the rockfall. It means that the subsequent major rock avalanche was more likely due to the impact of the rockfall on the rock slope below, which broke the rock bridges and caused drop of shear resistance along the fractures. According to these new understandings, a different triggering mechanism for the landslide is proposed.  相似文献   

20.
通过对滑坡地质环境和变形监测的分析,论述从持续强降雨入渗,经土体饱水软化,到滑动面孕育的滑坡形成机制.并通过数值模拟分析变形破坏前后应力场、变形场和破坏区的分布特征,以深化对滑坡变形破坏特征的认识.  相似文献   

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