Study On Tectonic Geomorphology And Activity Of The Batang Fault Of Yushu,Qinghai

The Batang fault is a Holocene left-lateral strike-slip fault along with some reverse component,which has occurred many some earthquakes recorded in the history.It is main faults of the south branch of Yushu fault,and decomposed part of the strike-slip deformation of the Ganzi-Yushu fault within the Yushu section.We have accumulated a lot of scientific research on trunk fault,but there is a relatively small degree for branch fault.These branch fault often have relatively strong activity characteristics of late Quaternary,and branch fault also have the ability to produce big earthquakes.Therefore,the Batang fault is the most typical and the most representative branch fault,geological background,tectonic geomorphic features,geometrical,kinematics,tectonic significance and genetic mechanism of the study area are studied and analyzed by surface exploration,DEM data and trenches and so on.So author gets the preliminary insights:(1)Based on ArcGIS,analyzing the DEM data of the Bartang fault,and get the slope of the Batang fault is between 0-72 °,the fluctuation is between 0-1546 m,the ridge in the periphery is about 5000 m,the water density is between 0-0.75 km / km2,and the slope,topography,water density,maximum elevation,minimum elevation,and average elevation are affected by fault control.(2)The Batang fault is main faults of the south branch of Yushu fault,it and Yushu fault located performance for“?”,which is divided into three fault,they are the Baluotan fault,the Jiachana fault and the Balongda fault.The collapse of the Batang fault and the Yushu fault is generally low,so the elevation is generally low in the region,but the Batang fault area within the rupture of the SE gradually increased.The Batang fault is negative flower structure in the section,in the geometric characteristics,the NW to the left shear and NNE to the role of tension.(3)The average slip velocity of the Batang fault is 2.1~3.9mm/a and the average vertical slip rate is 0.22~0.69mm/a in the Quaternary.According to the analysis of the trough,the period of the earthquake was before 4550 a in Xinongda,the average recurrence period of the earthquake in Batang fault is about 1500 a,and the recurrence time trend is gradually shortened,and the Batang fault has the ability to produce Ms7.0~7.5 earthquake.(4)The Yushu fault and the Batang fault have the characteristics of the water system deflection,which caused by the tectonic activity.According to the water system deflection analysis,the activity of the different sections is obviously different.The activity of the northern section of the fault is stronger than the south in Dangjiang fault,and the activity of the north side is weaker than that of the south side in Jiegu-Jielong,and the Boluotan fault is the main fault of the Bartang fault,which is significantly stronger than that of the Jiachana fault and the Blongda fault.(5)According to the tectonic kinematics of the Batang fault zone,because of Yushu section of the Ganzi-Yushu fault,the Batang fault and the Ganzi-Yushu fault together constitute the three-point structure,causing the Batang fault and the Yushu section bear the strike-slip deformation of the Ganzi-Yushu fault,and the Batang fault decomposes about two fifths of the strike-slip deformation of the Yushu section of the Ganzi-Yushu fault zone.Qiangtang block of Tibetan plateau expand to southeast,which causing Qiangtang block in continuous sliding clockwise,so Ganzi-Yushu fault is formed under this background,however,the Batang fault is main faults of the south branch of Yushu fault,it is likely to be formed under this background.