RESEARCHES ON RELATIONSHIP BETWEEN THE DATA OF GPS AND FAULT DEFORMATION AND SEISMIC ACTIVITIES IN BOHAI AND ITS SURROUNDING AREA

On the shore of Bohai and its surrounding area in China,many fault deformational surveying sites were set up sequentially from 1967.With short leveling,short base line and short ranging net across fault,a lot of data have been accumulated.In 1992,GPS(Global Positioning System)was started in China.The two kinds of data are processed and introduced simply in this paper.The result from these two kinds of data are discussed.For earthquake risk area judgement,it is of interest to know where is compression area and where is tension area,and generally the compression area is looked on as risk area and called abnormal area.All the data from leveling,ranging,base line and GPS methods can give us the description about the deformational state of the crust-compression state or tension state.The observation intervals of the different kinds of data in time and space are different.GPS sites intervals are more than 30 Km,and only the horizontal component can be used(the precision of vertical component is not satisfied yet);the short ranging sides,base line and leveling courses are usually shorter than 2Km across faults.And the observation intervals of them are different too.The interval for GPS observation is more than 2 years (in the future it may be shortened),but most of the others are less than 2 months.Thus sometimes the two kinds of data in the same area might show different deformational state of the crust because of non-uniform deformation of the crust in time and space.The results of comparison have shown that some of the two kinds of data are consistent,a few of them are not,and then the results are discussed.