汶川Ms8.0地震驱动的同震及震后地质灾害空间分布

The spatial distribution of coseismal geological disasters triggered by the 2008 Wenchuan M8.0 Earthquake

汶川大地震驱动了大量的同震崩塌、滑坡等地质灾害,这些地质灾害同时造成了山谷中大量的松散堆积物堆积,并将以泥石流的形式进入河流系统,造成震后大规模的泥石流地质灾害,这也是地震灾区在震后面临的最为严峻的问题。根据本项目组的卫星影像处理和实地观测工作,以及前人对同震地质灾害研究获得的数量资料,对同震地质灾害数量在平行于断裂方向和垂直于断裂方向两个方向上的分布特征进行了精确刻画,据此确定了同震地质灾害引发的松散堆积物的空间分布情况,并根据震后三年来泥石流地质灾害发生区域,确定泥石流地质灾害高危区的宏观分布:在北东—南西方向上,映秀与北川之间、平通与青川之间为泥石流地质灾害高危区;在北西—南东方向上,北川—映秀断裂以东10～15km、以西16～37km的范围内为泥石流地质灾害高危区。这些宏观分布数据可为震后群发性泥石流地质灾害的预测和防治提供重要的参考依据。

Wenchuan earthquake triggered a large number of geological disasters： collapse and landslide, which lead to a lot of loose deposits in the valleys. The loose deposits will be scoured to the rivers in the debris flow disasters. It＇s the most important problem in the earthquake-hit areas after earthquake. Based on the satellite imagery, site experiments and the quantitative text of eoseismal geological disasters researched by others, the project described the distribution characteristics of eoseismal geological disasters in the two directions： one direction is parallel to the rupture and the other direction is vertical to the rupture. Based on the distribution of debris flows in the three years after earthquake, the project also confirms the macroscopic distribution of loose deposits and the macro- scopic distribution of the area vulnerable to debris flows, which is the direction of northeast to southwest, the areas between Yingxiu and Beichuan, Pingtong and Qingchuan are vulnerable to debris flows. In the direction of northwest to southeast the area, from where the distance is 10 - 15 km east off Beichuan - Yingxiu fault and 16 -37 km east off Beichuan - Yingxiu fault respectively, is vulnerable to the disaster of debris flows. The data of macroscopic distribution will provide an important reference for the prevention and prediction of the debris flows after earthquake.