Abstract: Considering the great role of comprehensive analysis of seismic activity in earthquake prediction, an integrated parameter R_t of seismicity has been proposed in this paper. R_t consists of several seismic factors, including earthquake frequency, average magnitude, seismic entropy, b value and modulation ratio, it describes the total deviation of seismicity state from the normal in a given time interval. When R_t=1, the state of seismic activity is stable, otherwise, the seismic state is unstable in varying degrees. The variation of R_t with time has been studied for earthquakes occurred in North China, Northeast China and Northwest China regions as well as for mining earthquakes. The preliminary results show that R_t deviates from 1.0 clearly before the large earthquake occurrence. The efficiency of earthquake prediction by use of R_t parameter has been also estimated.

Key words: Integrated state, Multi-parameter, Efficiency estimation of earthquake prediction