The Performance Evaluation For Earthquake Early Warning System In Capital-zone Of China

Earthquake early warning(EEW)is an effective approache for mitigating the seismic hazard in recent years.China is one of the country which is troubled with serious earthquake disaster,and the government is actively promoting the construction of earthquake early warning system.With the precondition of no actual seismic test,the performance evaluation for earthquake early warning system is a very important work.The research takes the Chinese capital zone as the study region and uses the theory of ground motion transmission.Under the assumptions of existing and planned early warning stations' distribution,analysis of time-delay and the multiconditional warning information release scheme,this paper make an evaluation of the efficiency for Capital-zone's EEW system based on the evaluation indexes such as the interstation distance of early warning stations,the time of trigger a number of stations,the number of triggered stations in fixed time window,elapsed time,blind zone,and lead time.An overview of the research is as follows:1.Divide the existing and planned early warning stations' distribution into 4 scheme,define the interstation distance,analyse and compare the average interstation distance of 4 scheme,and give suggested value of minimum interstation distance for capital zone's early warning system based on the relationship between the blind-zone radius and the interstation distance.2.Using the method of grid discretization,research counts the time of trigger 1-10 stations and the number of triggered stations in 5s,10,15 s,20s since the earthquake occurrd.On this basis,research combines the previous results with the early warning stations' distribution scheme and set 11 early warning information release conditions.The research obtains the distribution map of elapsed time and the blind-zone radius.3.Based on the 196 times greater than M4.0 historical earthquakes since 1970 in capital zone,research calculates the elapsed time of the early warning system,and analyse the maximum suffered intensity and lead time for early warning target cities.What's more,the research takes the 1976 Tangshan earthquake as an example,and obtains the results of the blind-zone radius of EEW system and the lead-time for early warning target cities.