Using the data of leveling during 1971~1996,mobile gravity observations during 1993~2005,and GPS data during 1999~2004 in Guanzhong area,the space-time variation characteristics of the crust deformation of this area are studied.
The measurement of earth tilt is an important method of studying earth crust deformation and its earth tide, which means much to Geodynamics and the observation of earthquake prognostic.
We have discussed the basic theory of coupling movement between the crustal deformation and density change,and studied the gravity change with time raised by this coupling movement.
Study on crustal strain field is a basic field in geodynamic researches. The researches in the field are mainly centralized in the survey and studies of the crustal deformation, including the leveling survey and GPS survey in a large area, etc.
The main pattern of the crustal deformation is a clockwise rotation vortex structure and a differential slip along the boundary fault between different blocks.
Some earthquakes in recent years (such as Tangshan earthquake (1976, China), North Ridge earthquake (1994, USA), Kobe earthquake (1995, Japan)) did not occur in known faults; moreover, the detailed data of geology, earthquake, crust deformation, etc.
Polycrystalline quartz ribbons in high-grade metamorphic rocks from the Daqingshan region, are typical microfabrics of, and provide information for, deep crust deformation and metamorphism.
The images of main precursor mode have the characteristic of main shock-after shock type, which is agreement to the model of coupling movement between crust density and crust deformation (DD mode of coupling movement).
The main pattern of the crustal deformation is a clockwise rotation vortex structure and a differential slip along the boundary fault between different blocks.
The inhomogeneity in spatial distribution of short-to-imminent precursors increases before a strong earthquake, which may relates to the enhancement of crustal strain field.
In this paper, progress in strain study of blocks and faults by GPS data are discussed, and the concept that active structures between blocks are the main body of crustal strain is clarified.