Preliminary Study On Uncertainty Analysis In Earthquake Early Warning Processing

Earthquake Early Warning?EEW?system is an effective means of disaster mitigation.Due to its high timeliness requirements,the information used has the following characteristics:?1?the finiteness of the trigger station;?2?the limited information of the station waveform information.?3?The real-time and automation of data processing.Event discrimination,seismic phase picking,real-time estimation of magnitude,real-time seismic location and ground motion prediction all have certain uncertainties,which together lead to certain earthquake warning information.Certainty.In this paper,we do the following work on how to quantify the uncertainty of earthquake warning information:?1?Using the real-time estimation method of magnitude based on Bayesian theory,combined with historical seismic information and real-time waveform information provided by seismic monitoring stations,the uncertainty of real-time estimated magnitude is effectively quantified,and the factors affecting the uncertainty of magnitude estimation in real time are studied.The results show that different real-time magnitude calculation methodst_p^max??_c and P_d methods have no effect on the uncertainty of real-time estimation magnitude.The network density,seismic prior information and the quality of the waveform information provided by the station will all determine the uncertainty of the real-time estimation magnitude.?2?Using the improved“not-yet-triggered”approach,making full use of the information that has arrived and not arrived,effectively quantifies the uncertainty of real-time seismic location.Through research,it is found that the intra-and extra-network earthquakes and the P-waves that are not picked up by the stations will have an impact on the uncertainty of real-time seismic location.?3?Using a simple mathematical model to quantify the uncertainty of ground motion prediction equations.The uncertainty analysis method of ground motion parameters is used to quantify the uncertainty of PGA obtained by real-time estimation,and the method is applied to Hokkaido earthquake.The results show that the uncertainty analysis method of ground motion parameters can target different target locations.Different PGA thresholds give the PGA's overshoot probability in real time and quantify the uncertainty of ground motion parameters.The uncertainty of real-time estimated magnitude,the uncertainty of real-time seismic location and the uncertainty of ground motion prediction equation are compared to the uncertainty results of ground motion parameters.The research shows that the uncertainty of real-time seismic location has no effect on the results,and the uncertainty of the real-time magnitude estimation and the ground motion prediction equation has the same degree of influence on the results.