基于时序InSAR技术的西山黄土滑坡形变特征分析

Analysis of deformation characteristics of Xishan Loess Landslide based on time series InSAR technology

黄土滑坡具有范围广、易受降雨影响、危害性强等特点,黄土滑坡监测具有重要意义。传统地表形变监测技术耗时费力,难以满足大范围监测需求。本研究以青海省同仁市西山黄土滑坡为研究对象,选取2017年3月20日-2021年12月24日哨兵1A (Sentinel-1A)卫星48景升轨数据为研究数据,利用短基线集合成孔径雷达干涉测量技术(Small Baseline Subsets Interferometric Synthetic Aperture Radar,SBAS-InSAR)对研究区进行配准、差分干涉、滤波、相位解缠、重去平、形变建模与解算等处理,获取了该区域的时序形变特征。结果表明,西山黄土滑坡群共有2处明显的形变区。第一处形变区位于研究区东北部,其雷达视线向年平均形变速率介于-34.27~2.73mm/a;第二处形变区位于研究区中部,其雷达视线向年平均形变速率介于-30.27~4.20 mm/a。本文结合同仁市该时段的月降雨总量进行分析,结果表明降雨对滑坡形变速率具有正反馈作用。结果分析和野外调查表明,SBASInSAR技术在滑坡形变监测方面具有有效性,为该区域滑坡灾害防治提供了有效的技术支持。

Loess landslides have the characteristics of wide range,susceptibility to rainfall,and high harmfulness,which makes their monitoring significant.However,traditional surface deformation monitoring techniques are timeconsuming and laborious.In this study,the Xishan Loess Landslide in Tongren city,Qinghai province is taken as an example,the Small Baseline Subsets Interferometric Synthetic Aperture Radar(SBAS-InSAR)technique has been used to register,differential interferometry,filtering,phase unwrapping,reflatten,deformation modeling and calculation of Sentinel-1A 48 scene orbit data from March 20,2017 to December 24,2021 in the study area,and obtain the temporal deformation characteristics of the area.The results show that there are two obvious deformation areas in the Xishan landslide group.The first area is located in the northeast of the study area,with an annual average deformation rate in the direction of radar line of sight ranging from-34.27 to 2.73mm/a.The other area is located in the central part of the research area,with an annual average deformation rate in the direction of radar line of sight ranging from-30.27 to 4.20mm/a.Further combined with the analysis of the total monthly rainfall in Tongren city during this period,it is shown that rainfall has a positive feedback effect on the landslide deformation rate.Based on the result analysis and field investigation,it is shown that the SBAS-InSAR technology is effective in monitoring landslide deformation,and it provides effective technical support for the prevention and control of landslide disasters in this area.Furthermore,based on the analysis of the total monthly rainfall during this time period in Tongren city,the landslide deformation rate is positively correlated with the total monthly rainfall.Based on results analysis and field investigations,the effectiveness of SBAS-InSAR technology in landslide deformation monitoring has been demonstrated,providing effective technical supports for landslide disaster prevention and control in the region.