Fault Activity Rate About Typical Sections Of Zemuhe Fault Zone

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.