Construction And Application Of Crust Elastoplastic Deformation Model Of Bohai Rim Region Based On GPS Data

The movement process caused by crustal movement and deformation and the specific causes of deformation are currently hot topics in geodynamic research.In recent years,with the continuous development and improvement of space geodetic technology,it has provided a new way for many scholars to carry out research on crustal movement and deformation,especially in the internal deformation of the plate and the mutual movement between the plates,etc.However,most of these studies continue the traditional geophysical methods,making the current research lack of systematic constraints.In this paper,considering the limitations of the traditional crustal motion rigid body model,it is difficult to take into account the limitations of the internal deformation of the plate.In order to solve the problem that the existing crustal motion model is too strong in the study of plate motion and deformation,two crustal elastoplastics based on the essence of mathematical methods are proposed.Sports model.According to the objective physical mechanism of crustal movement,the model compensation idea is adopted,and different mathematical methods are used to describe the internal deformation of the plate.Relying on the GPS observation data from 2009-2015 in the Bohai Rim region of the China Mainland Tectonic Environment Monitoring Network(CMONOC),the crustal movement and deformation elastoplastic motion models in the Bohai Rim region were constructed to analyze the movement of the major plates in the Bohai Rim region.Specific research contents include:(1)Elaborate on the research principle of traditional rigid body crustal movement model,analyze the limitations of the model in the study of crustal movement and deformation process;Discuss the theory and methods of establishing crustal movement model based on space geodetic observation data and geophysical data.Explore the main problems of using space geodetic observation data to study crustal movement and deformation.(2)In view of the shortcomings of the traditional rigid body crustal motion model,the part of the plate that deviates from the overall rotation is regarded as uniform strain and linear strain,to construct two elastoplastic motion models,namely the block integral rotation with uniform strain model(REHSM),and the block rotation with linear strain model(RELSM).Relying on CMONOC observation data,the elastoplastic motion model of the Bohai Rim region is established,and the Euler motion parameters and related strain parameters of each major plate in the Bohai Rim region are solved;quantitatively calculate the fitting rate residual values of the three models,compare and analyze the fitting accuracy of the three models,explore the applicability of the three models in the study of crustal deformation in the Bohai Rim region.The results show that the two elastoplastic crustal movement models have no significant difference in fitting rate residuals overall,but they are better than the traditional rigid body motion model.(3)The overall rotation and uniform strain model of the block takes into account the internal deformation of the plate,but it assumes that the part of the plate that deviates from the overall movement trend belongs to uniform strain.Due to the complexity of the geological structural conditions and the randomness of the internal deformation of the plate,it is difficult to accurately quantify the internal deformation of the plate.According to the theory of least squares configuration,the part of the plate that deviates from the overall movement trend is regarded as a signal,and the Gaussian exponential function is selected to establish the model of integral rotation and uniform strain optimized by least squares configuration method(LSCREHSM).The optimized model and the first two elastoplastic motion models are used to construct the Bohai Rim motion model,and the Euler motion parameters and fitting rate residuals of the three models in each major plate are solved.The results show that the optimized model has higher fitting accuracy and can more accurately describe the crustal movement in the Bohai Sea region.(4)The block integral rotation with uniform strain model(REHSM)and the block rotation with linear strain model(RELSM)have strong assumptions in the construction of the model,which is difficult to apply in areas with complex geological structures.Therefore,a semi-parametric crustal elastoplastic motion model is proposed.The semi-parametric theory"non-parameter" is used to quantitatively describe the part deviating from the overall motion trend in the plate,the GPS observation data of all major plates in China's mainland are used to verify the correctness of the model.Finally,the elastoplastic motion model of the Bohai Rim region was further established,and compared with the internal block rotation with uniform strain model optimized based on the least squares configuration method.Semi-explore the consistency and differences between the uniform strain model based on the least square configuration method and the semiparametric model.The results show that the semiparametric elastoplastic motion model is significantly better than the former in fitting rate residuals.