滨海附近地区 G P S和断层形变与地震关系研究

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

简要介绍了环渤海及华北部分地区跨断层形变资料的分析结果，同时介绍了 １９９２年至 １９９５ 年首都圈两期 Ｇ Ｐ Ｓ测量资料处理分析的初步结果。通过比较，二者所显示的地壳活动趋势存在性质上的差异，主要是因观测时段的不一致而引起；在同时段资料的对比分析中，因测点和断层空间分布差异的存在，有 ４４．８％ 的流动资料难以判定其与 Ｇ Ｐ Ｓ资料的一致性，但在可判定的３３ 项资料中，有８９％ 是一致的，证明二者从不同的侧面反映了近几年地壳应力场的异常活动， Ｇ Ｐ Ｓ在十几公里至几十公里的空间尺度内反应了地壳形变量的平均水平，而跨断层测量在几十米至数百米的尺度内反应了断块边缘处的相对运动，是地壳应力活动在断块边界处的一种反映。二者理应既有区别，又有联系，既有矛盾，又存在共性特征。 Ｇ Ｐ Ｓ测量对地震危险区域的判定效果较好，跨断层形变测量对判定危险时段效果较好。

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.