从卫星图像上认识西藏易贡滑坡

Understand Yigong Landslide in Tibet Based on the Satellite Image

介绍易贡大滑坡发生的第 4天至滑坡坝溃决前卫星遥感监测滑坡环境的状况。西藏易贡大滑坡发生后 ,收集了滑坡发生前后不同卫星的多个时相的数据 ,经数字图像处理及与地形图精确配准形成彩色正射图像 ,对这些卫星图像进行解译后认为易贡大滑坡是喜马拉雅造山运动地貌演变过程中的一次大规模重力侵蚀活动 ,活动性质为高速碎屑流滑坡。碎屑流发生后堆积物整体基本稳定 ,但札木弄沟后端伴随着雪崩还有一定规模的活动 ,在 41d内碎屑流覆盖面积在 12 .9— 11.4至 12 .4— 10 .0km2 范围变化。滑坡堵江后 4— 41d ,易贡湖面积变化为 19.9— 43.6km2 。由于正处积雪融化季节 ,湖水上涨的速度很快 ,而坝体脆弱 ,预测随时有溃决的危险。 2 0 0 0 0 6 10 ,滑坡坝溃决 。

This paper describes environmental conditions of Yigong landslide before it occurence and from the 4th to the 41st days during the landslide occurring. With multi temporal different satellite data, through digital image processing and precise registration with the topographic map for the landslide region, the color ortho images are formed. Based on the interpretation of these images, it is understood that the occurrence of Yigong landslide is a large scale gravity erosion activity in the process of Xi\|Ma\|La\|Ya Orogenic movement, and its activity style is “high speed debris flow landslide”. The entire debris flow body has been basically stable since the disaster happened, but the back end of the Zhanalong gully is still moving with the snow avalanche. The exposed area of the landslide has been varied in the limitation of 12.9\_11.4 to 12.4\_10.0km\+2 and the Yigong lake varied from 19.9 to 43.6 km\+2 during the 4th\_41st days since landslide occurred. Owing to snow melting, the lake area became larger and larger quickly but the landslide dam was weak, it was thus deduced that the dam could burst at any time. It was bursted on Jun. 10, that conforms with the deducing result.