滇中汤郎-易门断裂构造活动的地貌特征  

Geomorphic Characteristics of Tectonic Activity of Tanglang-Yimen Fault in Central Yunnan

作　　者：刘昌伟 常祖峰[1] 庄儒新[1] 李鉴林 Liu Changwei;Chang Zufeng;Zhuang Ruxin;Li Jianlin(Yunnan Earthquake Agency,Kunming 650000,Yunnan,China)

机构地区：[1]云南省地震局,昆明650000

出　　处：《震灾防御技术》2021年第4期641-650,共10页Technology for Earthquake Disaster Prevention

基　　金：云南省地震自立科研项目:滇中汤郎-易门断裂带第四纪活动的构造地貌特征(2020K02);云南省地震局自立科研项目(漾濞地震专项)大理漾濞M_(s)6.4地震地裂缝特征及发震构造探究(2021YBZX17)。

摘　　要：汤郎-易门断裂位于青藏高原东南缘,走向近南北,按地貌特征及区域构造背景可将其划分为北段(营盘村-插甸断裂)、中段(插甸-碧城断裂)及南段(碧城-易门断裂)。针对汤郎-易门断裂构造地貌差异,利用30 m分辨率的DEM数据,基于GIS技术提取与断裂活动相关的水系,并计算其陡峭指数,结合野外考察及遥感影像讨论断裂在不同分段的活动习性与地貌特征。研究发现,区域内降水及基岩抗风化能力对亚流域陡峭指数的影响较小,认为陡峭指数能够较好地反映汤郎-易门断裂的垂直构造运动。陡峭指数显示,断裂走向呈两端高、中间低的特点,其分段性与前人划分结果具有较好一致性,所表征的基岩垂直活动性差异可作为断裂带活动分段的依据。断裂带东西侧陡峭指数在不同分段上表现出差异性,北段断裂东西侧陡峭指数显示出东、西向差异性抬升不显著,其与地貌上断裂北段表现的左旋走滑运动一致,以水平运动为主;断裂中段及南段陡峭指数在东西侧表现出东高西低的特点,显示东侧较西侧基岩抬升更快,可能以垂直差异运动为主。The Tanglang-Yimen fault on the southeastern margin of the Qinghai-Tibet Plateau is a seismic structure with a close to north-south strike and segmental activity.Tanglang Yimen fault can be divided into north section(yingpancun Chadian fault),middle section(Chadian Bicheng fault)and south section(Bicheng Yimen fault),According to geomorphic features and regional tectonic background.Aiming at the structural geomorphology difference of the Tanglang-Yimen fault,we use DEM data with a resolution of30 m,based on GIS technology,extract the water system sub-basins that are closely related to the fault and calculate its steepness index.Combined with field surveys,remote sensing images and historical earthquakes,the different faults Segmented activities and geomorphological features are discussed.It is find that the influence of rainfall and weathering resistance of bedrock on the geomorphic index of the sub basin is relatively limited and the geomorphic index can better reflect the vertical tectonic movement of the Tanglang-Yimen fault.The geomorphic index shows that the fault trend is high at both ends and low in the middle,and the segmentation is consistent with the previous results.The vertical movement difference of bedrock shown by geomorphic index can be used as the basis for the activity segmentation of fault.The geomorphic index on the East and west sides of the fault zone are different in different segments.The distribution of geomorphic index(ksn)in the northern part of the fault zone is relatively stable,and the differential uplift of the two sides is not significant.The geomorphological features of the northern section of the Tanglang-Yimen fault are left-lateral strike-slip movement.Blocking ridge,offset ridge and synchronous dislocation are developed in Fawo,laomuba and zhidu areas.The geomorphic index(ksn)in the middle and south part of the fault zone is high in the East and low in the West,indicating that there is vertical differential movement,and the eastern side uplifted faster than the west side.

关 键 词：武定地震 汤郎-易门断裂 活动构造 陡峭指数 

分 类 号：P931[天文地球—自然地理学] P315