Late Quaternary Activity Of Eastern Part Of The Tazang Fault

The East Kunlun fault zone is the northeastern boundary of the Bayan Har Block.Also it is one of the major giant left-slip strike faults in the northern margin of the Tibet Plateau.The tectonic fault is part of the east extension of the East Kunlun fault zone.It is of great significance to understand the pattern of movement of the East Kunlun fault zone and further study about the dynamic mechanism of the eastern margin of the Tibet Plateau.And it is also very important to study the activity characteristics of the eastern Kunlun fault zone,Which can provide a very valuable basic information for the seismic hazard in the fault zone.Based on the analysis of the predecessors' data,we defines the geometric distribution characteristics of the eastern part of the Ta zang fault by the interpretation of the remote sensing image and the detailed investigation in the fied.Then we used the UAV,DGPS and dating(14C,light luminescence)to obtain the slip rate of segments of Tazang and Majiamo in the eastern part of the Tibetan fault is determined.Finally,combined with the GPS data of the eastern margin of the Tibet Plateau and its adjacent areas,we discussion the Role of the East Part of the Fault in the deformation of the Eastern Tibet Plateau.The main conclusions are as follows:.(1)The fault starts from the eastern part of the West of Duowa,followed by the Dongbei,Zhangzha Town,Miaozhai,Majiamo,the final termination of near the Shagali.The total length of fault is about 135km.The strike is about 310°-340°.According to the change of the strike and order,the eastern part of the Tazang fault is divided into three segments;Dongbei segment,Tazang segment,and Majiamo segment.The strike of Dongbei segment is NWW,and the is between 40°-60°.The length is about 50km;The strike of Tazang segment is NWW,and the is about 50°.The length is about 35km.Tazang segment and northeast segment is left-left left-order arrangement,near the Lama Gang to form a small pull sub-basin,The strike of Majiamo segment is NWW,and the is between 40°-65°.The length is about 50km.Majiamo segment and the Tazang segment is left-handed arrangement,in the snow-capped mountains at the line was squeeze area.(2)Through analysis of UAV and DGP of typical faulty landforms and the corresponding dating data.we obtain the slip rate of the Tazang segment and the Majiamo segment.For Tazang segment,the horizontal slip rate is 4.1mm/a.and the vertical slip rate is 0.6mm/a;For Majiamo segment,the horizontal slip rate is 1.67mm/a.the vertical slip rate is 0.25mm/a.(3)The horizontal slip rate of the tectonic fault from the Luocha segment to the Majiamo segment is reduced from 7.68?9.37mm/a to 1.67?4.1mm/a,and the horizontal slip rate is reduced by nearly 5mm/a.0.9mm/a attenuation to 0.25?0.6mm/a,the vertical direction decreased by nearly 0.45mm/a.There may be several reasons for the possible reduction in the rate of slip:(a)The activity of the eastern part of the Tazang fault has gradually decreased since the Holocene.(B)As the northeastern boundary of the Bayan Har Block.the eastern part of the Tibetan fault and the Longriba are broken and the Minjiang fault intersects.The decay rate of the slip rate may be due to the blockage of the South China block and the near-SN-NNE The movement of the fault zone,and the uplift of the Minshan block,that is,part of the slip due to the absorption of Minshan uplift,part of the transformation into the Long Ri dam fault,the fault of the Minjiang fault.(C)The attenuation of the slip rate is related to the tectonic deformation of the eastern margin of the Tibet Plateau.