汶川地震重灾区泥石流沟内崩滑物空间分布的RS-GIS定量方法

汶川地震在山区引发大量崩塌、滑坡,形成大量的固体松散碎屑物质堆积在沟谷内(CLCAR,崩滑碎屑区),使得地震山区泥石流活动性增强。以岷江上游四川省汶川县银杏乡、映秀镇的15条泥石流沟的SPOT遥感影像为基础,利用GIS技术对CLCAR空间分布进行分析。建立CLCAR与流域高程、主沟侧距和沟口纵距的分布函数T(x)、M(x)和G(x),对CLCAR的空间分布特征进行描述;并计算其积分(DT、DM和DG)作为CLCAR空间分布特征的定量化参数。结果表明,函数T(x)、M(x)和G(x)能够较全面描述CLCAR的空间分布特征,DT、DM和DG能够作为CLCAR空间分布特征的定量化参数。泥石流沟谷内CLCAR的空间分布对泥石流的形成及规模具有一定的影响;在对灾区泥石流研究时有必要考虑泥石流沟内CLCAR空间分布特征。

Distribution of Collapse and Landslide Clast Deposit in Debris Flow Basin with RS-GIS after Wenchuan Earthquake

There are many of Collapse and Landslide Clast Accumulation Regions(CLCAR),which from collapse and landslide induced by Wenchuan earthquake,in debris flow basins.So debris flow gully become more activity.In this study,choose 15 debris flow gullies for study in upstream of Minjiang River,from Yinxing to Yingxiu Town.Based on SPOT Remote Sensing images,the Collapse and Landslide Clast Accumulation Regions were identified.Using Geographic Information System technology to analysis spatial distribution of CLCAR;building spatial distribution equations T(x),M(x) and G(x) which describe spatial distribution of CLCAR from basin elevation,lateral distance from main gully and longitudinal distance from lowest point of basin.And use integrations(DT,DM and DG) of spatial distribution functions(T(x),M(x) and G(x)) as quantitative parameters to depict CLCAR spatial distribution.The study show that functions T(x),M(x) and G(x) can well describe spatial distribution of CLCAR in debris flow basin;and DT,DM and DG can use as quantitative parameters of CLCAR describe spatial distribution.The spatial distribution of CLCAR can effect formation and scope of debris flow.So necessary to study CLCAR spatial distribution of debris flow basin in Wenchuan earthquake zones.