汶川地震引发的次生山地灾害链--以火石沟为例  

Mountain disaster chain induced by the Wenchuan earthquake in the Huoshiguo Gorge

作　　者：徐梦珍[1] 王兆印[1] 施文婧[1] 王旭昭[2] 

机构地区：[1]清华大学水利水电工程系,水沙科学与水利水电工程国家重点实验室,北京100084 [2]北京矿产地质研究院,北京100012

出　　处：《清华大学学报（自然科学版）》2010年第9期1338-1341,共4页Journal of Tsinghua University(Science and Technology)

基　　金：国家“九七三”重点基础研究项目(2008CB425803);国家自然科学基金资助项目(50779027);水利部公益项目(200901078)

摘　　要：汶川地震引起岷江支流文井江上游的火石沟发生滑坡,随后泥石流、剧烈河床演变、生态破坏连锁发生,形成典型地震次生山地灾害链。为了研究此灾害链的灾害过程及成灾特征,开展了多次野外勘测。采用GPS、激光测距仪等测绘了灾害区的局部地形,结合遥感、地形图分析,得出地震前后该区地形变化。计算出火石沟滑坡体积约721万m3,泥石流将125万m3左右的滑坡物质带到下游;泥石流堆积体上持续发生剧烈河床演变,上游40万m3的泥石流堆积段达到初步稳定前所发生的泥沙搬运量达6万m3。各级灾害发生量沿灾害链衰减,衰减率约为1/6。经历灾害链的河段,大型底栖动物多样性剧减,河流生态遭到破坏。滑坡创造的约0.25 km2的新生缓坡地较稳定,简单加固后可用于新村镇建设用地。The Wenchuan earthquake triggered the Huoshigou landslide in the upstream part of the Wenjingjiang River. Following the landslide, debris flows, large fluvial deposits, and ecological changes occurred frequently, resulting in a secondary disaster chain. Field investigations combined spot surveys using a GPS and a laser distance meter, remote sensing, and topographic maps studied the processes and characteristics of the secondary disasters. Landscape changes in the Huoshigou Gorge are described in detail. The landslide volume was measured as around 7.21 million ma with the debris flows transporting 1.25 million m^3 of sediment to be deposited downstream. Intense fluvial process on the debris scoured down 0.06 million m^3 of sediment from the 0.4 million ma deposited debric. The volume of secondary disasters decreased along the disaster chain with an attenuation factor of about 1/6. Changes in the macroinvertebrate community in the area affected by the disasters showed that the river ecosystem was greatly disturbed. The flat land with an area of 0.25 km^2 created by the landslide gradually stabilized after the disasters and can be used for new villages after simple strengthening.

关 键 词：汶川地震 灾害链 火石沟滑坡 泥石流 灾害链衰减率 

分 类 号：P315.9[天文地球—地震学]