Abstract: Using cross-fault levelling data at fixed and mobile observational stations in North China and the North-South Seismic Belt , the vertical displacement rate at each site is calculated. The temporal evolution characteristics of cross-fault vertical displacement rate and fault-group synthesized rate before seven earthquakes are studied. The result indicates that the temporal-spatial evolution characteristics of fault vertical displacement rate are fairly well related to strong earthquake activity. Particularly , the spatial distribution of anomalous displacement rate and its a pproaching to the source region before an earthquake can be used to predict the location of earthquake occurrence. The synthesized curve of vertical fault displacement rate and exceedance of deviation limits can be the referential criteria for predicting the magnitude and time of the coming earthquakes.

Key words: Cross-fault displacement, Vertical displacement rate, Temporal evolution, Rate synthesizing