ISSN 1003-8035 CN 11-2852/P

    基于光学遥感技术的高山极高山区高位地质灾害链式特征分析以金沙江上游典型堵江滑坡为例

    An analysis on chain characteristics of highstand geological disasters in high mountains and extremely high mountains based on optical remote sensing technology:A case study of representative large landslides in upper reach of Jinsha River

    • 摘要: 金沙江上游地形切割强烈、山高谷深,为典型的高山峡谷区,受金沙江断裂带的影响,斜坡完整性差、岩体支离破碎,极易发生山体滑坡。根据遥感影像上滑坡地质灾害隐患的色调、平面形态、变形标志、微地貌等特征,建立了遥感解译标志,在金沙江流域直门达—石鼓段共识别出滑坡地质灾害隐患点87处,其中大型40处、特大型47处,结合区域地理、地质环境特征,分析了其基本特征和空间分布规律。研究区堵江滑坡地质灾害隐患具有明显的链式特征,大致可划为滑坡-堵江灾害链、崩塌-滑坡-堵江灾害链、滑坡-泥石流-堵江灾害链等3种类型,分别以色拉滑坡、汪布顶滑坡、探戈滑坡为例,基于光学遥感技术对其变形特征、链式特征进行了详细分析。从地理位置上看,金沙江断裂带明显控制了金沙江干流直门达—石鼓段的平面展布,新构造运动在断裂带各段活动周期、强度存在差异性,中段和南段活动性较强、应变积累更快,地震作用可能相对频繁,为巴塘以南的金沙江两岸有利斜坡区发生堵江滑坡提供了有利的区域地质环境背景。

       

      Abstract: The upper reaches of Jinsha River are typical high mountain canyon areas with strong terrain cutting and deep valleys. Affected by the Jinsha River fault zone, the slope integrity is poor and the rock mass is fragmented, which makes the mountain landslide prone to occur on both sides of the river. According to the hue, plane shape, deformation sign and microtopography of landslide hazards in remote sensing images, we establish the remote sensing interpretation signs. A total of 87 landslide were identified in Zhimenda-Shigu section of Jinsha River, including 40 large and 47 super-large ones. Based on the characteristics of regional geography and geological environment, we analyse the basic characteristics and spatial distribution of landslide. The landslide in the study area have obvious chain characteristics, including landslide –blocking river disaster chain, collapse – landslide – blocking river disaster chain, landslide – debris flow – blocking river disaster chain. Taking Sela landslide, Wangbuding landslide and Tange landslide as examples, the deformation characteristics and chain characteristics are analyzed in detail based on optical remote sensing technology. From the geographical view, the Jinshajiang fault zone obviously controls the plane distribution of the Zhimenda-Shigu section of the Jinsha River. The neotectonic movement has strong activity, faster strain accumulation and relatively frequent seismic action in the middle and southern sections of the fault zone, which provides a favorable regional geological environment background for the occurrence of river blocking landslide in the favorable slope areas on both sides of the Jinsha River.

       

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