Study Of Activity And Tectonic Geomorphology Of The Southeast Segment Of Ganzi-Yushu Fault

Ganzi-Yushu fault is a large strike-slip boundary fault,and there has occurred many large earthquakes.Based on the predecessor's academic achievement and the digital elevation model,the elevation,relief amplitude,swath profile,gradient and drainage system of the Ganzi-Yushu fault is acquired by ArcGIS software,and the characteristic of tectonic terrain is analyzed.Based on the theory of fractal,the fractal dimension of Yalong river and Yulong river is calculated,and the relationship between fractal dimension and Ganzi-Yushu fault is calculated.Based on the interpretation of aerial photo and the field investigation,the geometrical morphology and activity of Ganzi-Yushu fault is calculated.Based on the theory of fractal,the fractal dimension of the Ganzi-Yushu fault,and the relationship between activity and distribution of Ganzi-Yushu fault is calculated.The geomorphic map is mapped by total station and unmanned aerial vehicles,and the slip-rates of Ganzi-Yushu fault is summarized.In the end,the ancient earthquake is researched by trial trench excavated at Zhuqing.Conclusions are as follows:(1)The physiognomy and river of the study area are controlled by the southeast segment of Ganzi-Yushu fault.The relief amplitude and the gradient and the elevation are controlled by Ganzi-Yushu fault.The numerical value is different not only between the fault,but along the fault.The flow direction of the river has a same direction with the fault,and the higher linear density of the river is distributed in the basin which arranged along the fault.The Ganzi-Yushu fault lead to the linearization of the watercourse and the decrease of fractal dimension.(2)According to the distribution and fracture of the fault,the fault can be broke up into two-segment named Ganzi and Manigange.The southeast of Ganzi-Yushu fault is formed by a couple of parallel fault,and the southeast of the fault is more complex than the northwest.The NW fault has higher fractal dimension values than the NE fault,and the NW fault has more powerful control action than the NE fault.The Manigange segment of the Ganzi-Yushu fault has a larger fractal dimension value,and it shows that Manigange segment is more active and more complex on fault distribution.(3)The slip-rates of the middle portion of Ganzi-Yushu fault is higher than the both sides.According to the trench made in Zhuqing town,there are three paleoearthquake events,and they happened in 3830~7280a BP,3530~3830a BP,1320 a AD.