Songpan Ganzi And Adjacent Tectonic Deformation Characteristics And Its Numerical Simulation

The movement and deformation of the crust are the comprehensive effects of various kinds of the geodynamical processes on the ground, and the systematical response of the crustal medium to the plate tectonic and deeply dynamic evolution. Therefore, the research for them becomes one of important contents in the geodynamic studies. The characteristics of the movement and deformation of the crust were traditional determined with the geological and seismographic methods which can solve the deformation of the crust structure for simple shape and small range. As a result, it is necessary to employ numerical simulation to in vestigate the deformation of the crust for large scale and geodynamical processes.At first, the characteristics of the depth structure and deformation of the crust tectonics are described and analysed in this thesis. The Global Positioning System (GPS) measurements of current movement are generalized and analysed well. Two half-dimensional simulation of gravity anomaly at Xiahe-Longriba profile shows that there are several low velocity body, which depth are not equality.The principles of the finite-element method and the general process of the finite-element analysis in the elastic mechanics are simple. introduced at first in this thesis. The finite-element software, called the ANSYS, is used to simulate the displacement, stress and strain fields of the crustal movement in the Song Pan GanZi and its near region with the boundary constraint of the GPS observations combining with other geologic and geophysics results.The model is three-dimensions. Moreover, the stress and strain fields were simulate of the section of Maqing-Jingbian. The numerical results obtained in this study are closed accordance with the other corresponding results obtained by some authors. It implies that the model and the numerical results are reasonable and reliable.Based on the numerical results, the present characteristics of the tectonic stress field in the Song Pan GanZi and its near region are primarily discussed in this thesis. From the figure of the simulated stress field, it is found that the stress pattern is steady ,as a whole . The north-east compressive stress is dominant in this regions, the direction of the compressivestress chang to north-east-east near the east of region. The displacement of blocks reduce from south to north block. The direction of the movement is north-east in this region. It is suggested that the structure deformation in SongPan GanZi and its near region is a result of the control of the current stress fields. The dominant force that are generated by combined actions of the Indian and Eurasia plate collision lead to the cunent stress fields and the structure deformation.