Study On The Characteristics Of Crust Deformation In Yadong‐gulu Rift Constrained By GPS Measurements

China is a region with the strongest seismic activity in the global continent, severalstrong earthquakes happened in the new century. The Qinghai-Tibetan Plateau,which liesin the southwest region of China, with the highest and strongest seismicity. It is a productof the ongoing collision between Indian and Eurasian plates, with complex geologicalstructures, active faults and strong crust motion. There are many different opinions aboutthe tectonic mechanism of Qinghai-Tibetan Plateau especially about the several SN-rifts insouth. These rifts are key objects to help us figurt out the E-W trending extension of thePlateau. And the500km long Yadong-Gulu is the most important one. So it is useful tomonitor the crustal deformation on these rifits.With the rapid development and wide spread ues of space geodesy techniques,represented by Global Positioning System, it provides many data with large scale, highaccuracy and quasi-realtime for the development and application the geodetic inversion.The space scale of GPS data vary from region to the global, and its time scale vary fromseconds to years. Its precision of relative positioning for long baseline can reach themagnitude of10-9. The quantitative image of crust motion with high precision andspace-time resolution by GPS, is the important basic data for research on continentaldynamics. So we study on the characteristics of crust deformation in Yadong-gulu rift byusing the GPS data from Crustal Movement Observation Network of China.At first,we calculate the horizontal GPS velocity of the study region with45sites in itfrom2009to2011. Then set the Yadong-Gulu rift and Yarlung-Zangbo suture to verticalaxis and horizontal axis,we divide the area into4blocks. Inverse the velocity of the4blocks base on the block model. And integrate with the elastic block model and negativedislocation model to investigate the fault activity,locking ratio and locking depth. Theconclusions are as follow:1. The other3blocks’ Euler poles relative to the southwest one are:southeast(89.37°，27.91°，-2.56°/Ma),northeast (89.02°，28.94°，-2.87°/Ma),northwest(85.03°，27.98°，-0.93°/ma).2. Differential velocities of sites north and south of the Yarlung-Zangbo suture inTibet imply that the suture maybe active as a strike-slip fault, the dextral slip ratein right is4.5mm/a, and the left is2.2mm/a.3. The extension rate of the Yadong-Gulu rift in south is6.75±0.9mm/a and4,72±0.8mm/a in north, both of them are larger than geological observation.According to the inversion result, the locking depth of Yadong-Gulu rift is10km. And the locking radio of the middle of Yadong-Gulu rift is0.9.