滇中普渡河断裂相对构造活动性特征  

Relative Tectonic Activity of Puduhe Fault in Central Yunnan

作　　者：余华玉 董有浦 于良 张东越 王丹[1] 段佳鑫 任洋洋 李江涛[1] Yu Huayu;Dong Youpu;Yu Liang;Zhang Dongyue;Wang Dan;Duan Jiaxin;Ren Yangyang;Li Jiangtao(Faculty of Land Resources Engineering,Kunming University of Science and Technology,Kunming 650093,China;China Southwest Geotechnical Investigation&Design Institute Co.Ltd.,Chengdu 610052,China)

机构地区：[1]昆明理工大学国土资源工程学院,云南昆明650093 [2]中国建筑西南勘查设计研究院有限公司,四川成都610052

出　　处：《地球科学》2025年第1期336-348,共13页Earth Science

基　　金：云南省企业基础研究应用基础研究联合专项(No.202101BC070001-003);云南省“兴滇英才支持计划”青年人才项目(No.KKXX202421007)。

摘　　要：鲜水河-小江断裂带在滇中发散成数条SN向分支断裂,其中的普渡河断裂多次引发5级以上的地震,但其构造活动性的空间分布特征并不清晰.地貌指数对构造活动非常敏感,可以很好地指示构造活动性分布特征.利用30 m分辨率的数字高程模型(DEM)提取了普渡河断裂区域41个流域盆地,并将流域划分为北段(撒营盘-富民段)、中段(富民-晋宁段)、南段(晋宁-峨山段)三段,通过分析获得了面积高程积分(HI)、流域盆地不对称度(AF)、流域形状指数(BS)、谷底宽高比(VF)、标准化河流阶梯指数(SLK)、山前曲折度(S_(mf))、河流陡峭指数(K_(sn))这7种地貌指数来揭示研究区的相对构造活动分布规律.结果表明普渡河断裂的各地貌指数的空间变化特征不受非构造因素(降水和岩性)的影响,而表现为主要受构造活动影响.普渡河断裂相对构造活动性呈现出由北向南逐渐减弱趋势,且断裂东侧的构造活动性略弱于西侧.普渡河断裂构造活动性弱于小江断裂,表明川滇地块在挤出过程中,活动性强的区域主要集中在边界断裂带.The Xianshuihe-Xiaojiang fault zone diverges into several SN-trending branch faults in central Yunnan,among which the Puduhe fault has triggered earthquakes of magnitude more than 5 for many times,but its spatial distribution characteristics of tectonic activity are not clear.Because geomorphic index is very sensitive to tectonic activity,it can well indicate the distribution characteristics of tectonic activity.In order to study the distribution characteristics of tectonic activity of the Purduhe fault,41 basins in the Purduhe fault region were extracted by using digital elevation model(DEM)with a resolution of 30 m.The basin is divided into three sections:north section(Sayingpan-Fumin Section),middle section(Fumin-Jinning Section)and south section(Jinning-Eshan Section).Seven geomorphic indices including hypsometric curve and hypsometric integral(HI),asymmetric factor(AF),basin shape index(BS),the ratio of valley floor width to valley height(VF),normalized stream-length gradient(SLK),sinuosity of the mountain front(S_(mf))and the steepness index(K_(sn))were obtained through analysis.The results show that the spatial variation characteristics of geomorphic indices of the Puduhe fault are not affected by non-structural factors(precipitation and lithology),but they are mainly affected by tectonic activities.The relative tectonic activity of the Puduhe fault gradually decreases from north to south,and the tectonic activity of the east side of the fault is slightly weaker than that of the west side.The structural activity of the Puduhe fault is weaker than that of the Xiaojiang fault,indicating that during the extrusion process of the Sichuan-Yunnan block,the highly active area is mainly concentrated in the boundary fault zone.

关 键 词：滇中地块 普渡河断裂 构造地貌参数 相对构造活动性 工程地质学 

分 类 号：P546[天文地球—构造地质学]