Monitoring activity at the Daguangbao mega-landslide (China) using Sentinel-1 TOPS time series interferometry
Monitoring activity at the Daguangbao mega-landslide (China) using Sentinel-1 TOPS time series interferometry
复制标题
使用 Sentinel-1 TOPS 时间序列干涉测量法监测大光堡特大滑坡（中国）的活动
DOI：
10.1016/j.rse.2016.09.009
复制
发表时间：
2016-12-01
影响因子：
13.5
通讯作者：
Stockamp, Julia
中科院分区：
文献类型：
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作者：
Dai, Keren;Li, Zhenhong;Stockamp, Julia
2008年汶川地震（M-w = 7.9）引发的大广堡特大滑坡（中国）面积约8 km（2），是世界上最大的滑坡之一。专家预测，滑坡的潜在风险和不稳定性可能会持续几十年，甚至更长时间。因此，监测如此大规模滑坡的活动至关重要。Sentinel-1卫星的渐进扫描地形观测（TOPS）模式为我们提供了最新的高质量合成孔径雷达（SAR）图像，覆盖范围很广（250 x 250 km），使我们能够充分利用各种干涉合成孔径雷达应用。然而，TOPS模式向雷达信号引入了依赖于方位角的多普勒变化，这需要额外的处理步骤，特别是对于SAR干涉测量。Sentinel-1 TOPS数据已被广泛应用于地震，但基于TOPS数据的时间序列分析的性能需要进一步开发。在这项研究中，哨兵-1 TOPS数据调查滑坡震后活动的第一次。为了处理方位相关的多普勒变化，TOPS时间序列干涉测量方法的处理链的发展。由于大广堡滑坡是2008年汶川地震引起的山体整体崩塌的结果，现有的数字高程模型（DEM，如SRTM和ASTER）显示出高达约500 m的高度差。地震后获取的Tandem-X影像用于生成高分辨率的震后DEM。SRTM DEM的高梯度地形误差（即震前SRTM与震后实际高程之间的差异）以及山区的低相干性使得难以使用传统的干涉合成孔径雷达处理过程来获得精确的DEM。因此，在这项研究中，重新展平迭代方法，以产生一个精确的TanDEM-X DEM。通过对比震后Tandem-X DEM和震前SRTM DEM，估计同震大光堡滑坡的体积为1.189 +/- 0.110 x 109 m（3），与工程地质勘察结果一致。Sentinel-1的时间序列结果表明，即使在汶川地震发生8年后，大广堡滑坡的某些部分仍然是活动的（并显示出4个滑动带），并表现出8 cm/年的最大位移速率。TOPS在时间序列分析中的良好表现表明，最新的高质量的TOPS数据与时空基线提供了显着的潜力，在未来的干涉合成孔径雷达的应用。(C)2016作者爱思唯尔公司出版
The Daguangbao mega-landslide (China), induced by the 2008 Wenchuan earthquake (M-w = 7.9), with an area of approximately 8 km(2), is one of the largest landslides in the world. Experts predicted that the potential risk and instability of the landslide might remain for many decades, or even longer. Monitoring the activity of such a large landslide is hence critical. Terrain Observation by Progressive Scans (TOPS) mode from the Sentinel-1 satellite provides us with up-to-date high-quality Synthetic Aperture Radar (SAR) images over a wide ground coverage (250 x 250 km), enabling full exploitation of various InSAR applications. However, the TOPS mode introduces azimuth -dependent Doppler variations to radar signals, which requires an additional processing step especially for SAR interferometry. Sentinel-1 TOPS data have been widely applied to earthquakes, but the performance of TOPS data-based time series analysis requires further exploitation. In this study, Sentinel-1 TOPS data were employed to investigate landslide post-seismic activities for the first time. To deal with the azimuth-dependent Doppler variations, a processing chain of TOPS time series interferometry approach was developed. Since the Daguangbao landslide is as a result of the collapse of a whole mountain caused by the 2008 Mw 7.9 Wenchuan earthquake, the existing Digital Elevation Models (DEMs, e.g. SRTM and ASTER) exhibit height differences of up to approximately 500 m. Tandem-X images acquired after the earthquake were used to generate a high resolution post-seismic DEM. The high gradient topographic errors of the SRTM DEM (i.e. the differences between the pre-seismic SRTM and the actual post-seismic elevation), together with low coherence in mountainous areas make it difficult to derive a precise DEM using the traditional InSAR processing procedure. A re-flattening iterative method was hence developed to generate a precise TanDEM-X DEM in this study. The volume of the coseismic Daguangbao landslide was estimated to be of 1.189 +/- 0.110 x 109 m(3) by comparing the postseismic Tandem-X DEM with the preseismic SRTM DEM, which is consistent with the engineering geological survey result. The time-series results from Sentinel-1 show that some sectors of the Daguangbao landslide are still active (and displaying four sliding zones) and exhibiting a maximum displacement rate of 8 cm/year, even eight years after the Wenchuan earthquake. The good performance of TOPS in this time series analysis indicates that up-to-date high-quality TOPS data with spatiotemporal baselines offer significant potential in terms of future InSAR applications. (C) 2016 The Authors. Published by Elsevier Inc.