基于PS-InSAR和offset tracking技术的金沙江白格滑坡形变监测

Deformation Monitoring of the Baige Landslide in the Jinsha River Using PS-InSAR and Offset Tracking Techniques

2018-10-11西藏江达县波罗乡白格村附近发生山体滑坡,导致金沙江断流并形成堰塞湖。收集高分二号、高分三号卫星数据,分析滑坡形成的堰塞湖对上游村镇的影响,并基于Sentinel-1以及ALOS-2 PALSAR-2数据,分别应用PS-InSAR和offset tracking技术获取滑坡体在滑坡发生前的运动特征。结果表明,白格滑坡在灾害发生前已有明显的滑移,根据PS-InSAR技术结果,2017~2018年白格滑坡边缘处存在年平均视线向滑动速率超过2.5 cm/a的PS点,且在白格滑坡周边发现2处潜在滑坡;根据offset tracking结果,白格滑坡在2015-07~2018-07期间的3个时间段呈现出滑动不断加速的特征,滑坡累计滑动量超过30 m。应用InSAR技术可在滑坡灾害发生前识别出活动性滑坡,为滑坡监测预警提供重要依据。

On October 11,2018,a landslide occurred near Baige village,Polo town,Jomda county,Tibet.As a result,flow cut-off occurred in the Jinsha River and a barrier lake formed.Based on the GF-2 and GF-3 imagery,we analyze the influence of the barrier lake on villages and towns upstream.Based on Sentinel-1 and ALOS-2 PALSAR-2 images,we apply separately PS-InSAR and offset tracking techniques to obtain the motion characteristics of the landslide before the occurrence of the disaster.The results show that the Baige landslide has obvious slip before the disaster.According to PS-InSAR results,from 2017 to 2018,the average rate of some PSs in the LOS direction at the edge of the Baige landslide exceeds 2.5 cm/a,and two suspected landslides are found around the Baige landslide;According to offset tracking results,Baige landslide shows the feature of accelerating sliding in the three time periods from July,2015 to July,2018;the cumulative sliding distance exceeds 30 m.The application of InSAR can identify active landslides before landslide disaster occurs,providing an important basis for landslide monitoring and warning.