High Precision GPS Velocity Field And Crustal Deformation Characteristics Of The San Andreas Faults And Its Neighboring Region

GPS(Global Positioning System)measurement technology can quickly,efficiently and accurately provide 3D coordinates of stations accurately and the other information,it is gaining more and more widely used,because it has many advantages such as high precision,all-weather,real-time and so on,it provide multi-scale data of high precision for monitoring the global and regional crustal deformation and strain characteristics.In this paper,according to the special tectonic position of the San Andreas fault,interaction between the Pacific plate and the North American plate.It's geological structure is complex,earthquake activity is frequent,which making it as the longest and most active fault on the earth's surface,and this area has been the research focus of international,and it has a strong representation in the study of earthquake tendency.Therefore,timely access to regional high precision GPS motion velocity field,then based on the velocity field,the crustal strain characteristics is studied,and then analyzes the intrinsic relationship between strong earthquake activity and crustal deformation strain,which has an theoretical and reference value for grasping the current crustal tectonic activity and the mechanism of disaster dynamics.The main research contents and results are as follows:1?Based on the latest high precision GPS monitoring data of San Andreas fault and its neighborhood from 2010 to 2015,this paper adopts GAMIT/GLOBK high precision data processing software and adopts high precision data processing strategy to obtain the global ITRF2005 framework and relative to the North American plate reference datum for high precision crustal velocity field,which has mastered the deformation characteristics of crustal tectonics in the study area.2?Through analyzing on the velocity fields we can obtain:Under the framework of ITRF2005,the earth's crust of the San Andreas fault and its neighboring region as a whole towards to west-north,the Imperial Valley and Mojave region show a trend of clock wise rotation,the north of the fault movement rate is smaller,the southern of the fault movement rate is higher,the major reason may be that it is located on the junction of the Pacific plate and the North American plate,by the north to west squeeze of the Pacific plate,forcing the region's GPS station as a whole to towards to west-north;relative to the North American Plate rates became smaller,it have high speeds which located in the southwest side of the fault near the Pacific plate region,located in the northern part of the fault of the North American plate movement rate is smaller,which reflects the internal differences in structural deformation characteristics.3?Based on the regional crustal horizontal velocity field,this paper further uses the least squares collocation method to calculate the crustal horizontal strain field characteristic parameters of the San Andreas fault and its neighboring region,and then explore the relationship between regional crustal activity and its seismic activity.The results show that: The strain high value area is characterized by significant linear distributed along the San Andreas fault,with the main pressure strain,and the strain rate value presents the characteristics of the difference between the West and the East.The Ventura basin and the Salton Sea region are the high strain rate areas.According to the seismic data of the area,this paper further reveals that the region of high strain rate in the region is also a frequent area of moderate to strong earthquakes.