基于SAR/InSAR技术的雅鲁藏布江下游高位地质灾害早期识别

Early identification of high-elevation geohazards in the lower Yarlung Zangbo River based on the SAR/InSAR technology

雅鲁藏布江下游位于印度板块和欧亚板块碰撞的前缘地带,区域内新构造运动活跃,高山分布众多,属典型高山深切割区。由于独特的地质构造以及气候变化的影响,区域内崩塌、滑坡、泥石流等地质灾害频发。文章采用Sentinel-1影像以及ALOS/PALSAR-2影像通过多种时序InSAR技术和SAR偏移量技术联合的方式对区域内2014—2020年高位地质灾害进行了识别。文章研究结果表明:在研究区内共存在260处地质灾害形变区,且大多位于海拔较高的沟道与山峰;泽巴隆巴冰川沟中的岩崩形变体已经形成多条大型拉张裂缝,一旦发生崩落极有可能形成堰塞湖;受米林地震影响而复活的达波古滑坡后缘已经完全脱离,左右两侧裂缝完全贯通,滑坡一旦失稳会完全堵塞雅鲁藏布江。此研究提供了识别高山峡谷区高位地质灾害的SAR/InSAR技术方法,为类似的地质灾害识别提供了参考。

The lower stream of the Yarlung Zangbo River is in the front zone of the collision between the Indian and Eurasian plates with active neotectonics movements and many high mountains in this region.It is a typical mountain-valley area.Due to the unique geological structure and the influence of climate change,geohazards such as collapses,landslides,and mudslides frequently happen in this area.We used Sentinel-1 and ALOS/PALSAR-2 images to identify the high-elevation geohazards in the region from 2014 to 2020 by combining multiple time-series InSAR techniques and SAR offset-tracking techniques.The identification results show that there are 260 geohazardinduced deformed areas in the study area,and most of them are located in gullies and peaks at higher elevations.The rock avalanche deformations in the Zebalongba glacier gully have formed several large tension cracks,and once the avalanche falls,they are most likely to form a dam.The back edge of the Dabo landslide,which was reactivated by the Milin earthquake,has completely been detached,and the cracks fully penetrate the left and right sides.Once the landslide destabilizes,it will completely block the Yarlung Zangbo River.This study provides a general method for identifying high-elevation geohazards in high mountain-valley areas and a reference for similar geohazards identification.