ACTIVE TECTONICS OF THE EASTERN MARGIN OF THE TIBET PLATEAU

Abstract

The eastern margin of the Tibet Plateau is composed of the Minshan Block and Longmenshan.Studies on tectonic landform show that the average sinister slip rate is 1.4 mm/a with a vertical rate of 0.3 mm/a along the Huya fault since late Quaternary.The average vertical slip rate is between 0.37 mm/a and 0.53 mm/a along the Minjiang fault and the sinister slip is similar to the vertical one.Among the Longmenshan Tectonic Zone,the Wenchuan-Maowen fault,Beichuan-Yingxiu and Penxian-Guanxian faults have the average vertical slip rates of 1 mm/a respectively,and show same amount of right and vertical offsets.Based on the data of focal mechanism and GPS survey,a tectonic deformation model of southeastwards extrusion of the eastern marigin of the Tibet Plateau is proposed.