【作者】 余建强；

【导师】 田勤俭；

【作者基本信息】 中国地震局地震预测研究所 ， 构造地质学， 2010， 硕士

【摘要】 断层活动速率包括走滑速率和垂直速率,是衡量活动性断裂活动强度的重要标志之一,它反映了断层上应变能量释放的速率(杜平山,2000)。一般而言,若同一地区运动性质相同的断裂带进行比较,活动强度大的断裂带其走滑位移速率或垂直位移速率就大;若同一条断裂带的不同段落相比较,也是活动强度大的段落其走滑位移速率或垂直位移速率就大。断裂带滑动值的确定对进行强震重复间隔的研究,活动断裂分段研究,地震中长期预报和地壳稳定性评估等都是很有意义的(宋方敏等,1998)。则木河断裂带主体位于四川省凉山彝族自治州境内,北段在西昌以北与安宁河断裂带相交,南段过金沙江在巧家与小江断裂带相接,全长约130km,总体走向330°,由5条左阶羽列的次级剪切活动断层所组成,自北向南依次为李金堡断层、大箐断层、扯扯街断层、松新断层和大同断层(杜平山等,2000),是“川滇菱形断块”的东南边界断裂之一(闻学泽,1983),近代构造活动强烈,具左旋错动性质(黄祖智,1983),沿线左旋位错一系列水系、山脊、洪积扇等,历史上曾发生过多次强烈地震,是我国大陆强震集中、频度较高的地区。本文以则木河断裂带典型地段作为重点研究对象,以断层活动速率为研究目的,从以下两个方面对则木河断裂带进行了研究。1、时间标尺的建立第四纪时间标尺是建立在地质地貌综合研究和测年的基础上的。通过收集整理前人的研究成果,建立了区域范围内地层与地貌的关系,主要表现为区域内安宁河、雅砻江和金沙江沿线各级阶地的物质组成以及高程和年代的关系,为区域内其它地貌面年代的估算提供参考;应用航片、卫片的解译结合光释光、热释光、14C等测年方法识别了则木河沿线五道箐、松新、宁南等地各级阶地并推测其年代,为沿线其它地段阶地年代的确定提供参考。2、典型地段断层活动速率研究运用遥感解译、野外实地调查、差分GPS地震微地貌测量等方法,重点选取大箐梁子、五道箐、普格等地带开展断层活动速率综合研究。其中大箐梁子为干沟抬升量差分GPS测量与干沟定年;五道箐一带为洪积扇分期测年与断错地貌测量等;普格一带主要为水系位错量解译及研究区冰期气候旋回定年等。综合上述各段活动速率研究结果认为则木河断裂带晚第四纪以来走滑速率为2～6mm/a。更多还原

【Abstract】 The fault activity rate includes horizontal rate and vertical rate,which is one of the important symbols weighting activity intensity of active fault, it has reflected the rate of strain energy liberation on the fault(Du Pingshan,2000). Generally speaking, if we take the fault having same active character in the same area on comparison, the fault zone with intense activity has high?strike-slip or vertical rate; if we take different sections form the same fault on comparison, the sections with intense activity has high?strike-slip or vertical velocity. The determination of activity rate is meaningful for the research of recurrence intervals of great earthquakes, segmentation of active fault ,mid-long term earthquake prediction and evaluation of crustal stability(Song Fangmin et.al,1998).The main part of Zemuhe fault zone is located at Liangshan Yi autonomous prefecture in sichuan province, its north section intersects Anninghe fault zone at north of Xichang and its south section connects with Xiaojiang fault zone after crossing Jinsha River in Qiaojia, length about 130km, overall strike 330°. It is composed of 5 left-step pinnate arrangement secondary shear active faults, from north to south are Lijinbao fault,Daqing fault, Chechejie fault, Songxin fault and Datong fault in turn(Du Pingshan,2000), which is one of the northeast boundary faults of“Sichuan-Yunnan Rhombic Block”(Wen Xueze,1983). The modern structure activity is intense and has the sinister slip properties( Huang Zuzhi,1983). A series of river system,mountain ridge and diluvial fan are left-laterral slipped along the fault, and many strong earthquakes have occurred in history. The research area is a strong earthquake concentrated and high frequency area in mainland of China.This thesis takes the typical sections of Zemuhe fault zone as main research object, and takes fault activity rate as research goal, research the fault from the following two aspects: 1.Building time scaleQuaternary time scale is built on geology and geomorphology comprehensive research. Through the collection of predecessors’ achievements, we established the relationship between formation and physiognomy within area, which is mainly embodied the relationship between substance and altitude as well as age along terraces of Anninghe, Yalong River and Jinsha River within area, providing reference for the estimation of age about other geomorphology surface within area. Through reading the aerial and satellitic photographs combining OSL, TL and 14C dating methods, we identified terraces as well as inferred it’s age on Wudaoqing,Songxin and Ningnan along Zemuhe fault zone, and provided reference for the determination of age about terraces on other section along the fault.2. Fault activity rate about typical sectionThrough remote sensing interpretation,field investigations and micro geomorphology surveyed by deferential GPS, we selected Daqingliangzi,Wudaoqing and Puge for comprehensive research about fault activity rate. Daqingliangzi is mainly about the dry ditch deferential GPS survey of uplift value and dating;Wudaoqing is mainly about diluvial fan periodization and dating as well as dislocation geomorphy survey; Puge is mainly about extraction of river system dislocation and dating by ice age climate cycling. Summarizing above mentioned results We indicate Zemuhe fault zone strike-slip rate is about 2 ~ 6mm/a since late Quaternary.更多还原