Study On The Early Warning System Method Based On A Single Station's P Wave Record

In this paper,a method is proposed to estimate the earthquake's parameter quickly by only a few seconds of P wave recorded by a single seismic station. Earthquake event real-time monitoring, determine the P wave's first arrival and estimate the earthquake's parameter quickly are required technically.This paper is consisted of four chapers,three aspects are studied as follow:1. In this paper,the authors propose a new method(EGLP) of seismic event detection automatically which is based on non-fGaussian, non-linear , seismic wave polarization characteristics of seismic signal and STA/LTA method. Based on forty seismic events data of Shandong Seismic Network whose distance are smaller than 100km and magnitude is greater than 3.0,we got the seismic event trigger value. We found that new method could suppress the Gaussian noise and improved the accuracy of seismic event detection.2. Based on the AIC algorithm, we compared the capability of AR-AIC,VAR-AIC and TOC-AIC methods in determining the phase arrival,we found that phases identification are accurate using above three methods when the SNR was higher, and only VAR-AIC method is better than AR-AIC and TOC-AIC methods to phases identification when SNR is lower.3. Based on the seismic event detection and picking the P wave arrival automatically,we put forward a model to invert seismic magnitude and epicenter distance by one second data after P wave. Based on forty-one seismic events data of Shandong Seismic Network whose distance are smaller than 100km and magnitude is greater than 2.0, we concluded that we can locate earthquake by only 1 second data after P wave, although the result isn't very accurate, but it saved the location time,and confirm that it is possible to locate earthquake and earthquake early warning by only a few seconds of P wave.