甘孜—玉树断裂东南段构造地貌及活动性研究

发布时间：2018-03-17 00:31

本文选题：甘孜-玉树断裂　切入点：构造地貌　出处：《成都理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：甘孜-玉树断裂是一条以左旋走滑为主的大型边界断裂,历史上曾发生多次大地震。本文以其东南段为研究对象,在总结前人研究资料的基础上,基于数字高程模型(DEM)使用ArcGIS软件的空间分析工具提取了研究区地形起伏度、坡度、水系和高程条带剖面等信息,分析甘孜-玉树断裂东南段的构造地貌特征。基于分形理论,使用模拟网格法估算了研究区雅砻江水系及其支流的分维数,分析水系分维特征与断裂活动的关系。通过航卫片解译和实地调查,分析断裂的几何特征和空间展布情况。基于分形理论计算了断层展布的分维数,分析断层分维数的分布情况及其与断裂活动性的关系。使用无人机绘制微地貌图,总结断裂各段滑动速率,分析各段活动性的差异。最后,分析了竹庆开挖的探槽,研究断裂带上的古地震事件,得出以下几点认识:(1)甘孜-玉树断裂东南段地区地貌和水系明显受该断裂所控制。地形起伏度、坡度和高程等受断裂影响,表现为在断裂两盘和沿线明显的差异性;水系的流向和线密度受断裂影响,表现为水系流向与断裂走向近一致,水系线密度高的区域主要分布在断裂带沿线的盆地区;同时,因水系流向受断裂带控制而使河道趋直,靠近断裂带的水系分维值偏小。(2)依据断层展布及地表破裂分布特征将甘孜-玉树断裂东南段分为甘孜段和马尼干戈段两段。断裂由数条近似平行排列的NW向断层组成,断层展布总体表现为SE复杂,NW简单。以甘孜-玉树断裂为主的NW向断层分维值较高在研究区内具有较强的控制作用;马尼干戈至错阿附近断层展布的分维值较高,表现出更强的活动性和更复杂的断层分布。(3)甘孜-玉树断裂东南段滑动速率表现为中间大、两边小的特征。竹庆探槽揭露三次古地震事件,事件时间分别为3830~7280a BP,3530~3830a BP,1320a AD。
[Abstract]:The Ganzi-Yushu fault is a large-scale boundary fault dominated by left-lateral strike-slip, which has occurred many large earthquakes in history. In this paper, the southeastern part of the fault is taken as the research object, and based on summarizing the previous research data, Based on the digital elevation model (DEM), the spatial analysis tools of ArcGIS software are used to extract the information of terrain fluctuation, slope, water system and elevation strip profile in the study area, and to analyze the structural and geomorphological characteristics of the southeast section of the Ganzi-Yushu fault. The fractal dimension of the Yalong River system and its tributaries in the study area was estimated by using the simulation grid method, and the relationship between the fractal dimension characteristics of the water system and the fault activity was analyzed. Based on fractal theory, the fractal dimension of fault distribution is calculated, and the distribution of fault fractal dimension and its relationship with fault activity are analyzed. The slip rate of each segment of the fault is summarized, and the difference of activity in each segment is analyzed. Finally, the trench excavated by Zhuqing is analyzed, and the paleoearthquake events on the fault zone are studied. It is shown that the geomorphology and water system in the southeast section of the Ganzi-Yushu fault are obviously controlled by the fault. Topographic fluctuation, slope and elevation are affected by the fault, which is manifested by the obvious difference between the two plates of the fault and along the line. The direction and density of the water system are affected by the fault, which shows that the flow direction of the water system is nearly consistent with the strike of the fault, the area with high density of the water system is mainly distributed in the basin area along the fault zone, and at the same time, the flow direction of the water system is controlled by the fault zone, which makes the river channel straighten. On the basis of fault distribution and surface fracture distribution, the southeast section of Ganzi-Yushu fault is divided into two sections: Ganzi section and Manigango section. The fault is composed of several NW faults arranged approximately in parallel. The general distribution of the fault is SE complex and NW is simple. The high fractal dimension of the NW fault, which is dominated by the Ganzi-Yushu fault, has a strong controlling effect in the study area, and the fractal dimension of the fault distribution near Manigango to Puia is relatively high. It shows stronger activity and more complex fault distribution.) the slip rate of the southeast section of the Ganzi-Yushu fault is large in the middle and small on both sides. Three paleoearthquake events were revealed by the Zhuqing Prospecting trough, the event time being 3830 ~ 7280a BPU 3530 ~ 3830a BPN 1320a AD.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P542.3;P931.2

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