The Application Of Crustal Elastoplastic Deformation Model Based On GPS Velocity Field

As the main causes of humorous natural disasters such as earthquake,it's important to establish a quantity model to study diastrophic movement and its deformation,which not only can help us predict and prevent related geological disaster,but also can reveal the revolution and mechanism of geodynamics.Researchers in the past usually used geophysical and geological material,based on Euler rigid body rotation theorem to study diastrophic movement and its deformation.But the results was limited by the data and the model that were used.In recent 20 years,the rapid development of high precision space geodesic technology provides a new method for us however.But all related researches still rest on the verification of model of traditional rigidity plate movement,rarely focus on models systematically analyzing diastrophic deformation,especially lack in modeling approach.With GPS monitoring data of China crustal movement observation network in circum-bohai-sea region and related research results,This study based on theory of elastoplastic media,theory of crustal movement,geodetic data processing,etc.focused on the problem that traditional rigidity plate movement model can't consider internal block shape changes,established several elastic plastic deformation model considering internal shape changes,and analyzed crustal deformation in circum-bohai-sea region and main plate in China.The result shows that the new methods improve the traditional model in several respect:1.A method for selecting rigid stations based on hypothesis testing and robust estimation is established.The screening of rigid stations based on experience,a uniform station selection method that has not yet been agreed,in the past,make the rigid stations obtained after screening by different scholars are different from each other,resulting in great differences in crustal deformation analysis.Using the hypothesis test and robust estimation to screen rigid stations can improve the accuracy and reliability of the crustal deformation analysis.2.The global rotation and uniform strain model(REHSM)and the global rotation and linear strain model(RELSM)of the main blocks in the Bohai Rim region and China are established.The results show that the REHSM and RELSM elastic motion strain models consider the block internal deformation and greatly improve the GPS velocity field fitting accuracy comparing the Euler rigid body motion model.Using the REHSM and RELSM models can not only Acquiring Euler motion parameters but also obtaining deformation strain parameters within the block,and in most regions,RELSM results have a slight advantage over REHSM results.3.The REHSM model optimized by the least squares allocation method is proposed.Although the REHSM and RELSM take into account the intra-plate deformation and greatly improve the traditional rigid body motion model,its assumption that the internal deformation of the block presents “uniform” and “linear” changes still have considerable limitations.In complex geological formation areas,this assumption may be difficult to meet.It is proposed to use the signal to describe the irregular deformation within the block,and to establish an improved least squares configuration model for the crustal deformation analysis of REHSM.Because the improved model does not require the internal deformation law of the block,the REHSM model is theoretically developed.In the process of estimating the parameters of the empirical covariance function,the new model uses the classical NNR-NUVEL1 A model parameters to center the GPS velocity field data.This avoids the interference of outliers on data centering and makes the results obtained after configuration have a certain physical significance.Considering the difference in space and direction of the crustal movement,the speed field is partitioned during modeling and analysis.Directional fitting.The fitting analysis results of previous research on GPS velocity field data of major blocks in the Chinese mainland and Bohai Rim region show that this method can achieve better fitting accuracy.5.A semi-parametric analysis model for crustal deformation was established,and the solution method for pollution semi-parametric model was proposed.The Euler rigid body motion model is used to describe the overall movement trend of the block,and the non-paramete is used to description of the internal irregular deformation of the block,establishing a semi-parametric model for crustal deformation analysis.In view of the fact that the data in the crustal deformation analysis is often influenced by many factors and contains gross errors,a robust semi-parametric model solution method combining the robust estimation method with the compensated least squares criterion is proposed;in the modeling analysis,the time series is used.The method of constructing a regular matrix has obtained good analytical results,indicating that it is reasonable to use the time series method to determine the regular matrix in the crustal deformation analysis.6.Proposed quasi-accurate crustal deformation-resistant Kriging analysis method.Considering that only the function model or statistical model is used to process the velocity field data,the obtained fitting residual will more or less contain some effective information.It is proposed to use a reliable function model to fit the velocity field first,and then The crustal deformation analysis method that uses the Kriging model to extract the effective information from the processing results and use it;To prevent the abnormal value from affecting the modeling analysis,a pseudoverification method is proposed to resist the gross errors,thereby improving the block deformation analysis modeling reliability.7.The crustal deformation analysis method that combines the polynomial method and the Kriging method is established.The polynomial model is used to describe the trend(main movement)part of the crustal movement,and then the Kriging method is used to compensate for irregular deformation within the block(see the random disturbance of the paired trend movement),and the polynomial method and the Kriging method are established.Fusion crustal deformation analysis method.This is a comprehensive model that combines the regularity of the function model with the flexibility of the statistical model to improve the reliability of the crustal deformation.