华北地区地壳垂直形变散度场及其演化特征

推导出了用傅里叶级数表示的地壳垂直形变散度场的计算公式，对华北地区三十多年的精密不准测量资料进行了计算，绘制了各时间段的散度等值线图，并以该区地震活动的散度场背影进行了分析研究，初步得到如下几点认识：（１）散度图象中的正源区和负源区是成对出现的，散度密集带分布在正源区和负源区之间，零散度图象中的正的区和和负源区之间。（２）散度密集带和华北地区断裂构造带在分布上呈一致性，表现在大多数散密度密集带和

THE CHARACTERISTICS OF THE DIVERGENCY FIFLD OF VERTICAL CRUSTAL DEFORMATION AND EVOLUTONG IN NORTH CHINA

In this paper, the formula that shows the divergency field of the vertical crustal deformation is deduced from Fourier series, and the data of the precise levelling for more than 30 years in North China were calculated. We draw a map of equal value of the divergency for each period and analyzed the relation between the earthquake activity and the divergency field in this area. The conclusion is as follows:(1) It is found by couples for the positive source region and the negative source region in the divergency map. The high density divergency field distributes between positive source region and negative source region, and the naught divergency field is also located among the positive source region and the negative source region. (2) It is loomed unanimously in distributing for the high density divergency belt and the structure fissure belt in North China, and most of them are unanimous in strike. (3) It is shown from the distribution of the interval formula among the positive source region and the negative source region that the divergency map moves from South to North and from East to west with the elapes of time.(4) The naught of divergency region of vertical crustal deformation field is a certain of the positive region of vertical crustal deformation field. The source region is a short-lived phenomenon, which are the scattered and the observed, and then it can keep the moving state for the inherence of crust. The short -lived phenomenon prefigUre a new pattern of crustal movement and the earthquake preparation would be finished. When the positive sourve region and the negative source region is occuring alternately, it is the normal state, but when the source- free region is occuring, it is perhaps an anomalous phenomenon.