Research And Application Of Horizontal Crustal Movement Field Model In The Bohai Rim Region Based On GPS Data

Crustal movement and deformation have an important influence on the earth's environment,climate and people's production and life.Severe crustal movements can even cause major natural disasters such as earthquakes,landslides and tsunamis.When conditions are serious,people's lives and property will be endangered.The study of crustal movement and deformation has great practical value.This paper uses the GPS observations of the CMONOC in the Bohai Rim region between 2009 and 2015,based on the commonly used fitting method and the improved Euler vector method,to study the construction of the horizontal movement field model in the region,by contrast and analysis modeling precision,establishing an optimal horizontal motion field in the Bohai Rim region.Based on existing research data to reclassify the study block,select the optimal model of each block,and establish an optimal block-level horizontal movement field.The results show that research results more in line with the conclusions of geological movement and provide a basis for further study of the deformation of the Bohai Rim region.The research progress and contents of this paper mainly include:(1)The characteristics of commonly used fitting methods and Euler vector methods are analyzed,and the evaluation methods of the models are discussed.Based on the fitting method of linear fitting,quadratic surface fitting,multi-plane function and Euler vector method,two models of internal inspection and external inspection were selected to establish a model.Comparing and analyzing the modeling accuracy,obtaining the best fitting motion model of the Bohai Rim region.Considering that there are differences in the motion mechanisms in two different directions,creative proposals are made to select the optimal fitting model in different directions,select 0.5°×0.5°grid to interpolate to get an optimal overall horizontal movement field based on a fitting model in the Bohai Rim region.(2)For limitations of the Euler vector method,Explained the proposed basis and modelling principle of the elastic-plastic model for motion deformation in slabs,and establish a comprehensive model that integrates the elastic plastic models and Euler vector models.For the parameter in the calculation of two elastic-plastic models,the linear function expression in the elastic plastic model was improved and a new comprehensive model was obtained.(3)Based on three comprehensive models,choose internal inspection and external inspection to establish models,contrast analysis modeling accuracy.The results show that Euler vector and linear strain models and improved model all have good results.Comparing the modeling results of this two models with the optimal fitting model,the results show that the best fitting model in the east-west direction has better modeling results,and the two comprehensive models in the north and south have better modeling results.It is due to the fact that the deformation in the east-west direction is relatively flat,while the faults in the north-south direction are more frequent and the changes are more severe.Select the best fitting model in the east and west direction,improved model in the north and south direction,select 0.5°”0.5° grid interpolation was performed to establish an optimal overall horizontal movement field in the Bohai Rim region.(4)Based on the existing research data,the block division was reconstructed by combining the fault data in the Bohai Rim region.Select two verification schemes and use the three models verified to build separate models for the divided blocks,comparing with modeling accuracy,get the optimal model of each block in different directions The 0.5°×0.5°grid is used to interpolate and get the optimal block 1 horizontal movement field in the Bohai Rim region.