ISSN 1003-8035 CN 11-2852/P

    西藏然乌地区地质灾害隐患点InSAR识别与监测

    InSAR identification and monitoring of geological hazards in Ranwu region of Tibet

    • 摘要: 西藏藏东南地区地处青藏高原东南部,地势陡峭。多期次板块构造运动、岩体间相互挤压运动导致地质灾害频繁发生且规模大。针对该区域的地质灾害调查与监测研究工作对防灾减灾具有重要意义。文章以藏东南然乌地区为研究区,分别利用升降轨Sentinel-1A卫星数据对该区域隐患灾害点进行识别,并分析了SAR影像几何畸变对地质灾害识别的影响。通过对InSAR监测结果进行分析,文章最终共圈定了区域内的滑坡、冰川隐患灾害点67处。同时,为了更好的分析灾害体的形变特征和规律,选取了然乌区域安目错北岸三处典型冰川灾害体,利用多维小基线子集(MSBAS)技术获取了坡体的二维(水平东西向和垂直向)形变速率和时间序列。通过对吉穷隆冰川、迫弄冰川和瓦巴村冰川三处典型冰川的形变时间序列结果进行分析,发现从2018年1月到2020年10月,三个冰川水平东西方向上的最大累计位移量分别达到了202 mm、283 mm、194 mm,垂直方向上最大累计位移量分别达到了97 mm、−155 mm、−163 mm。水平方向上三处典型冰川表现为加速变形趋势,垂直方向上表现为缓慢蠕滑变形趋势。同时分析了瓦巴村冰川二维形变时间序列与降雨量和温度相关性,结果表明降雨和温度的变化对坡体冰川形变具有一定的影响。研究成果对高山峡谷区地质灾害隐患点的识别具有较好的参考价值。

       

      Abstract: Southeast Tibet, located in the southeast part of Qinghai-Tibet Plateau, is characterized by steep terrain, frequent occurrence and large scale of geological disasters due to multiple plate tectonic movements and compression movements between rock masses. It’s of great significance to investigate and monitor geological disasters in this region. In this paper, Ranwu area in southeast Tibet is taken as the study area, and the potential disaster points in this area are identified by using sentinel-1A satellite data, and the influence of geometric distortion of SAR image on geological disaster identification is analyzed. Through the analysis of InSAR monitoring results, 67 hidden danger points of landslides and glaciers in the region were delineated. At the same time, in order to better analyze the deformation characteristics and laws of the disaster bodies, three typical glacial disaster bodies in the north bank of Anmuco in Ranwu region were selected, and the two-dimensional (horizontal EAST-west and vertical) deformation rates and time series of the slope bodies were obtained by using multidimensional small baseline subset (MSBAS) technology.Based on the analysis of the deformation time series results of Jiqilong Glacier, Polong Glacier and Waba Village Glacier, it’s found that the maximum cumulative displacement in the horizontal east-west direction from January 2018 to October 2020 is 202 mm, 283 mm and 194 mm respectively. The maximum cumulative displacement in vertical direction is 97 mm, −155 mm and −163 mm respectively. In the horizontal direction, the three typical glaciers show an accelerated deformation trend and slow creep deformation trend in vertical direction. At the same time, the correlation between the two-dimensional deformation time series of Wabacun glacier and precipitation and temperature is analyzed. The results show that the variation of precipitation and temperature has certain influence on the deformation of slope glacier. The research results of this paper have a good reference value for the identification of geological hazards in alpine and canyon areas.

       

    /

    返回文章
    返回