Extracting damages caused by the 2008 Ms 8.0 Wenchuan earthquake from SAR remote sensing data
Extracting damages caused by the 2008 Ms 8.0 Wenchuan earthquake from SAR remote sensing data
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DOI：
10.1016/j.jseaes.2010.07.009
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发表时间：
2011-03-03
影响因子：
3
通讯作者：
Wang, Xiaoqing
中科院分区：
文献类型：
--
作者：
Dong, Yanfang;Li, Qi;Wang, Xiaoqing
恶劣的气象条件限制了光学遥感图像的获取，而全天时、全天候的合成孔径雷达（SAR）显示出为震后应急救援提供及时遥感数据的能力。由于合成孔径雷达对地震引起的地表变化很敏感，地质灾害和建筑物倒塌引起的电磁行为变化可以作为后向散射强度变化记录在合成孔径雷达图像中。对SAR产品进行绝对辐射定标，由图像数字数（DN）得到后向散射系数σ 0。基于变化检测方法，利用高级陆地观测卫星（ALOS）L波段相控阵合成孔径雷达（PALSAR）数据和TerraSAR-X数据对汶川8. 0级地震进行震害信息提取。这项研究表明，滑坡显示出较强的后向散射和堰塞湖显示出较低的后向散射在地震后10米ALOS PALSAR图像相比，地震前，倒塌的建筑物显示出较低的后向散射相比，未倒塌的建筑物在1米TerraSAR-X图像。结果表明，不同空间分辨率的SAR数据对不同震害类型的信息提取都有一定的适用性：中等空间分辨率的SAR数据（如10 m ALOS PALSAR数据）对次生地质灾害信息提取是有效的;高分辨率合成孔径雷达数据，例如1米TerraSAR-X数据，借助辅助地理信息系统数据或高分辨率光学数据，可用于城市建筑物倒塌信息的提取。研究表明，SAR遥感数据可以在地震应急阶段提供早期的震害信息，为现场调查、进一步的震害评估和震后重建提供辅助。皇冠版权所有（C）2010由爱思唯尔有限公司出版。保留所有权利。
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. Crown Copyright (C) 2010 Published by Elsevier Ltd. All rights reserved.