Abstract:Through the processing and analysis of multiperiod precision leveling data in northern area of North China,it is found that the decline of largenumber in a largearea has appeared in the western region to capital circle, the direction of contour lines is mainly to the NE, and they take vertical intersection with Zhangbo fault (NWW). There is a close relation of spatial distribution of vertical deformation to the tectonic activity, the characteristic of “up southdown north” and “up eastdown west” is inconsistent with the longterm trend of tectonic movement of “high northlow south” , which is a “inverse inheritance movement”. In the western region of the studied area, the quadrantshaped distribution appears with Yanggao area as the center, relative increase of the south and north sides, relative decline of the east and west sides and the maximum difference value is 26 mm/a. This deformation state is similar to that before the Datong earthquake, however, the character of the deformation is absolutly different from Datong earthquake (up onedown another). Tectonic activities in the northern area of North China began to shift from the normal activities to the abnomal activities in 2008, it may be a strong earthquake signal.
Han Yueping, Chen Fuchao,Yang Guohua et al. CHARACTERISTICS OF PRESENTDAY CRUST VERTICALDEFORMATION AND EARTHQUAKE RISK ANALYZES IN NORTHERN AREA OF NORTH CHINA[J]. jgg, 2010, 30(2): 25-28.