The Research On The Characteristics Of Crustal Deformation In Fenwei Rift Zone

Fenwei rift zone is one of the most intense seismic belt in seismic activity in North China region, its seismic activity is closely related to the seismic activity of the other three seismic belt in North China area, Fenwei rift zone plays a decisive role in the North China tectonic activity pattern, and reflects the strength of tectonic activity in North China and the dynamic changes in North China area. In addition, it is the key area for regulating tectonic movements among Ordos block, North China block and South China block, the geological structure of the zone is complex and the earthquakes occur frequently, especially in recent years, the frequent earthquakes above 4 level causes the wide attention of scholars. Today, using GPS technology to monitor crustal deformation and seismic precursor has already become a hot spot to study characteristics of crustal deformation and earthquake gestation mechanism, the use of this technology not only promote the development in the research of crustal motion and deformation, but also has important significance on seismic activity judgment and earthquake prediction.In this paper, we collect some information about the characteristics of the tectonic setting, fracture and seismic activity in this zone, and according to the 2009-2013 GPS monitoring data, we get the velocity field results under ITRF2008 with the help of GAMIT/GLOBK software, then use the Euler vector method to calculate Euler rotation parameters of the Eurasian plate under ITRF2008, and obtain the GPS horizontal velocity field of Fenwei rift zone and its adjacent area relative to the Eurasian plate, these practices provide direct and quantitative data for the crustal movement in the study area. Through the profile analysis across the fault, we study the state of strain accumulation of the major active fault zone, using the distance weighting Gaussian smooth method to calculate five groups of crustal strain characteristic parameters in Fenwei rift zone, including the principle strain rate, the dilatation, the maximum shear strain rate, the first shear strain rate and the second strain rate, the crustal deformation features here were analyzed in a deeper depth. Combined with the conclusions to analyze the relationship between the deformation characteristics and seismic activity, and explore the driving source of the tectonic movement and dynamic evolution model.