基于InSAR技术的夏藏滩滑坡区地表变形监测与分析

Surficial deformation monitoring and analyzing to the Xiazangtan landslides based on InSAR method

黄河上游两岸巨型滑坡发育,对以龙羊峡水电工程为代表的黄河上游梯级电站以及当地居民生产生活和生命财产安全等带来一定影响和潜在危害。为研究黄河上游巨型滑坡分布区地表形变特征,以位于青海尖扎境内的黄河上游右岸夏藏滩滑坡分布区为研究区,利用升轨、降轨Sentinel-1A影像数据,采用InSAR技术对滑坡体地表形变信息进行提取和分析,并通过实地调查对基于InSAR技术监测结果进行现场验证。结果表明:采用升轨、降轨Sentinel-1A影像数据所获得的区内滑坡体地表最大形变速率分别为24mm/a和21mm/a,最大累计变形量分别为133mm和128mm;2017—2022年监测周期内,随着监测时间增加,位于夏藏滩滑坡前缘的次级滑坡特征点A和B累计位移量呈逐渐增加的变化趋势;基于PS-InSAR和SBAS-InSAR两种方法所得到的滑坡体地表累计变形量具有一致性特征,该结果表明InSAR技术适用于黄河上游拉干峡—寺沟峡流域巨型滑坡体地表变形的监测。该研究结果不仅为开展黄河上游巨型滑坡地表变形监测提供有效方法,而且为该流域有效防治古滑坡复活提供数据支撑和实际指导。

The development of super large scale landslides on the upper reaches of the Yellow River has brought certain impacts and potential hazards to the cascade power stations in the upper reaches of the Yellow River represented by the Longyang Gorge Hydropower Project,as well as the production,life,and property safety of residents.To analyze the surface deformation characteristics in the distribution area of super large scsle landslides in the upper reaches of the Yellow River.This study used InSAR to extract and analyze the surface deformation information of landslide by using Sentinel-1A image data of ascending and descending orbit in the Xiazangtan landslide area in the upper right bank of the Yellow River in Jianzha County,Qinghai Province.The monitoring results based on the InSAR method were then verified on site through field investigation.The results show that the maximum deformation rates of the landslide surface in the area obtained from the ascending and descending Sentinel-1A image data are 24 mm/a and 21 mm/a,respectively,with the maximum cumulative deformation of 133 mm and 128 mm.During the monitoring period from 2017 to 2022,with the increase in monitoring time,the cumulative displacement of secondary landslide feature points A and B located at the landslide front of Xiazangtan showed a gradual increase trend.The cumulative deformations of landslide surface obtained based on PS-InSAR and SBAS-InSAR methods have consistent characteristics,and the results show that the InSAR method is suitable for monitoring the surface deformation of super large scale landslide from Lagan Gorge to Sigou Gorge in the upper reaches of the Yellow River.This study not only provides an effective method for monitoring the surface deformation of super large scale landslides in the upper reaches of the Yellow River,but also provides data support and practical guidance for the effective prevention and treatment of ancient landslide resurrection in the basin.