Global Tectonics Characteristics Inferred From Space Geodesy

The techniques of Earth Observation System (EOS) provide powerful tools to measure the lithosphere of the earth with high coverage, high precision and high temporal and spatial resolution. Especially, the space geodesy promotes the development of the geo-science; it makes quantitative analysis of the recent lithosphere movements possible. The main purpose of this dissertation is to study the applications of EOS data in geo-science research, and the emphasis is put on the global and regional tectonics characteristics research using space geodesy. The contents are arranged as follows.1 The development and status of the research on the global plate motionThe basic conceptions of plate tectonics are presented. The observations, methods and the modeling algorithms of the geology and traditional geophysics for global plate motion research are also recommended. The development and conclusion of it is summarized. The applications of space geodesy in global plate motion is introduced, the evolvement of the International Terrestrial Reference Frame (ITRF) series, the research methods, the results and the comparisons of the different models inferred from space geodesy are given. Furthermore, the shortage of rigid motion model is analyzed.The results obtained from the geology and traditional geophysics is corresponding with those of the space geodesy, so the precision of them is credible and the models are reliable too. They can verify each other, and they are also important basis for the study on the reliability and stability of plate movement. The difference of plate partition, the quantity of data, the quality of data, the distribution and the data preprocessing and so on will leads to obvious different plate motion models, even systematical difference.2 The uncertain approximation of the plate tectonics theoryOn the basis of the conception of plate, the uncertain approximation of plate tectonics is discussed. All types of diffuse plate boundaries are analyzed. According to the results obtained from the Global Strain Rate Map Project, the plate nonrigidity is studied. The plate is not rigid as the assumption, for deformation is occurred not only on the plate boundaries, but also in the interiors. The hypothesis test results show that the plates are not rigid and stable.3 The Realization of No-Net-Rotation conditionAccording to the ITRF definition provided by the International Earth Rotation Service (IERS), the no-net-rotation (NNR) condition of crust is strictly established in the spherical coordinates, the tensor matrixes of main plates are deduced, and the tests on the global plate motion models are also carried out. The result shows that the number, quality, distribution of the data obtained from space geodesy is not enough to do the detailed research. The ITRF still exist some rotation as a whole, it is not independent from the geology model assumption. The plate motion models so far do not satisfy the no-net-rotation condition, they are only approximate NNR models.4 The research of criterion in data preprocessingThere are many observe techniques in space geodesy, but some differences exist among them, such as reference frame, precision, distribution and so on, so the data obtained from space geodesy should be preprocessed before modeling. Aiming at resolving some problems in the data preprocessing before plate motion modeling, which leads to the various even unreasonable results, moreover, the effects of many factors such as the boundary of plates or blocks, seismic activity and the precision of velocity field and so on are not definite, the classical mathematics has no ability to describe them, so fuzzy sets and pattern recognition is adopt to establish the criterions and processes in the data preprocessing. It includes data selecting, mutual stations uniting, supervise clustering and spatial distribution equalizing.In the data selecting part, the effects of plates or blocks boundaries, the seismic activity, the velocity precision and so on are all take into accounted, it uses fuzzydegree to quan...