Using repeated precise gps campaigns for research of present-day crustal movement and strain in the Qinghai-Tibetan Plateau

The problem of crustal movement in the Qinghai-Tibetan Plateau is a hotstop ic of the present day international geodetic world, GPS observations in 199 3, 1995 and 1997 are used to survey the three-dimensional displacement of G PS monitoring station in the Qinghai-Tibetan Plateau, and to calculate and analyze the present-day crustal movement and strain in the Qinghai-Tibetan Plateau, The result of repeated campaign shows that the crustal movement in the Qinghai Tibetan Plateau is still compressing in the north and south di rections, extending in the west and east directions, and uplifting in the v ertical direction. The relative convergence velocity of the Himalayan block is approximately (19.5 +/-1.7)mm/a, the strain velocity is about (5.5 +/-6 .0) mm/a, and the uplifting velocity is some (7.6 +/-5.2) mm/a, The compres sion velocity of the Tibet block relative to Golmud in the north and south directions is (9.3 +/-4.6) mm/a, the strain velocity of the middle part in the west and east directions is (15.6 +/-6.3) mm/a, reflecting the plateau lateral extruding movement, The Himalayan block is mainly compressing strai n, and the middle part of the Tibet block is mainly extending strain, The h ighest extending and the compressing strain are 0.131x10(-6)/a and -0.189x1 0(-6)/a, respectively.