金沙江结合带巴塘段滑坡群InSAR探测识别与形变特征

金沙江结合带结构破碎,软弱岩层发育,流域性特大高位地质灾害频繁发生。针对该区域开展大范围滑坡调查与监测研究,对减灾防灾具有重要意义。以金沙江结合带巴塘段为试验区,采用堆叠InSAR技术分别利用升轨、降轨Sentinel-1A卫星数据对该区域滑坡隐患开展了调查研究。在此基础上,以中心绒乡滑坡群为重点研究区,利用多维小基线子集技术获取了区域二维形变速率(水平东西向和垂直向)及二维时间序列结果。通过对4处典型滑坡体的形变时间序列结果进行分析,发现在两年时间段内安里克米滑坡、仁娘村滑坡、贡伙村滑坡1和贡伙村滑坡2水平方向累积位移量分别达到44.3、-26.6、65.3和-77.1 mm,垂直向累积位移量分别达到-30.2、-88.3、-80.9和-56.9 mm,且这4处滑坡呈现缓慢蠕滑变形趋势。通过对贡伙村滑坡2的形变监测二维时间序列与降雨数据分析发现,强降雨对滑坡变形有一定短暂影响。由于滑坡群处于地质条件脆弱地区,构造活动强烈,在强降雨条件下极易导致滑坡失稳,建议对其进行持续监测,同时该研究成果对流域内其他区域的滑坡调查与监测研究具有参考意义。

Detection,Identification and Deformation Characteristics of Landslide Groups by InSAR in Batang Section of Jinsha River Convergence Zone,China

In Jinsha river convergence zone, the structure is broken, weak rock formations are developed, and the geological disasters in super-high position occur frequently. Investigation and monitoring of large-scale landslides in this area is of great significance for disaster reduction and prevention. Taking Batang section of Jinsha river convergence zone as a test area, stacking-InSAR technology was used to investigate and study the potential landslide hazards by using the date of Sentinel-1A satellite from ascending and descending orbits. On this basis, the Zhongxinrong township landslide group was selected as the key research area, and the multi-dimensional small baseline subset(MSBAS)technology was used to obtain the regional two-dimensional deformation rate(horizontal in east-west and vertical)and two-dimensional time series results. Through the analysis of the deformation time series results of four typical landslides, it is found that the horizontal cumulative displacements of Anlikemi landslide, Renniangcun landslide, Gonghuocun landslide 1 and Gonghuosun landslide 2 reach 44.3, -26.6, 65.3 and -77.1 mm within two years, respectively; and the vertical cumulative displacements reach -30.2, -88.3, -80.9 and -56.9 mm, respectively. The above four landslides all show a slow creep deformation trend. By analyzing the relationship between the deformation monitoring two-dimensional time series of Gonghuocun landslide 2 and rainfall data, it is found that strong rainfall has a certain transient impact on the landslide activity. The landslide group is located in the region with fragile geological conditions and strong tectonic activities, which can easily cause landslide instability under the condition of heavy rainfall. Therefore, continuous monitoring is recommended. At the same time, the results have important references significance for landslide investigation and monitoring research in other areas of Jinsha river convergence zone.