摘要
海原断裂带是中国西北地区重要的活动断裂带,也是青藏高原东北边界的重要组成部分。海原断裂带活动性研究对深入了解青藏高原东北缘构造格局和第四纪构造地貌具有重要意义,对于地质灾害预测和地质风险评估也有很大的参考作用。本次研究基于数字高程模型(DEM)数据,利用ArcGIS软件对该段各流域的地貌参数进行提取计算,定量获得该段各流域的地貌形态特征,最后对研究区的相对构造活动性程度进行分析。面积-高程积分(HI)表明断裂带两侧的地形梯度差异显著,断裂带及其南侧盆地坡度更大,山地更陡峭,地貌侵蚀作用也更强。流域盆地不对称度(AF)表明研究区内海原断裂带中东段由西至东发生掀斜的程度越来越小,流域盆地的形态也从不对称向对称变化。盆地延伸率(Re)则显示断裂北侧盆地的狭长程度要明显高于断裂南侧,但更倾向于由于早期构造活动或者地壳停止运动后的缓慢调整和变形造成。标准化坡降指数(SL)结果显示断裂带南侧河流坡降较大,北侧则较小;经过断裂的流域SL值中,王滩-黄鼠滩段(西段)明显要高于其他段,表明此段的地貌演化的活跃程度明显更高。地震活动则显示断裂东段地震更为密集,但西段受哈斯山段复杂的断层-褶皱系统影响较大,因此综合地形特征因子的分析结果,可以推断海原断裂带中东段存在断裂活动性差异。南侧地形陡峭、起伏较大且河流发育良好,表明该区域可能存在较活跃的构造活动,而北侧地形相对平缓、河流发育较弱以及较小的坡降指数,则表明该区域可能存在较弱的构造活动。
The Haiyuan fault zone is an important active fault zone in northwestern China and an important part of the northeastern boundary of the Qinghai-Tibet Plateau.The study of the activity of the Haiyuan fault zone is of great significance for understanding the tectonic framework and Quaternary tectonic geomorphology of the northeastern margin of the Qinghai-Tibet Plateau,and also has a great reference for geological disaster prediction and geological risk assessment.Based on the digital elevation model(DEM)data,this study used ArcGIS and other software to extract and calculate the geomorphological parameters of each basin in this section,and quantitatively obtained the geomorphological characteristics of each basin in this section,and finally analyzing the relative tectonic activity of the study area.The hypsometric integral(HI)shows that the topographic gradients on both sides of the fault zone are significantly different.The slope of the fault zone and its southern basin is larger,the mountain is steeper,and the geomorphic erosion is stronger.The asymmetric factor(AF)indicates that the degree of tilting from west to east in the middle and eastern part of the Haiyuan fault zone in the study area is getting smaller and smaller,and the shape of the basin also changes from asymmetry to symmetry.The elongation ratio(Re)shows that the basin on the north side of the fault is significantly narrower than that on the south side of the fault,but it is more likely to be caused by early tectonic activity or other reasons.The stream length gradient(SL)shows that the slope of the river on the south side of the fault zone is larger,while that on the north side is smaller.Among the SL values of the faulted basin,the Wangtan-Huangshutan section(western section)is significantly higher than other sections,indicating that the activity of geomorphological evolution in this section is significantly higher.The seismic activity shows that the earthquakes in the eastern section of the fault are more intensive,but the western section is greatly affected by the complex fault-fold system in the Hasishan section.Therefore,the analysis results of the comprehensive topographic characteristic factors are obtained,it can be inferred that there are differences in fault activity in the middle and eastern sections of Haiyuan fault zone.The terrain on the south side is steep,undulating and the river is well developed,indicating that there may be more active tectonic activities in this area.The relatively flat terrain on the north side,weak river development and small slope index indicate that there may be weak tectonic activity in this area.
作者
刘禄山
周小虎
王阳
黄琪
Liu Lushan;Zhou Xiaohu;Wang Yang;Huang Qi(State Key Laboratory of Continental Dynamics,Department of Geology,Northwest University,Xi'an 710069)
出处
《地质科学》
CAS
CSCD
北大核心
2024年第4期1111-1131,共21页
Chinese Journal of Geology(Scientia Geologica Sinica)
基金
国家自然科学基金项目(编号:42272266)资助。
关键词
海原断裂带
活动性分析
地形特征因子
数字高程模型
Haiyuan fault zone
Activity analysis
Terrain feature factor
Digital elevation model
