Research On The Correlation Between Early Warning Parameters Of P Wave And Magnitude Or Ground Motion Intensity In Strong Earthquakes

Earthquake early warning (EEW) system provides a few seconds to tens of seconds of warning time for impending ground motions due to a large earthquake and allows for mitigation measures in the short term. As a very important means for preventing and reducing earthquake disaster, earthquake early warning (EEW) has received considerable attention from international society in recent years. First, we give a short introduction about the basic idea of earthquake early warning and the development of the theory about earthquake early warning. Then, we give a study on the rapid magnitude estimation of earthquake early warning and the rapid determination of peak ground motion parameters. The contents are summarized as follows:(1)34earthquakes that happened after the20th century are selected and the magnitudes are all greater than5. We use the information of these earthquakes to verify the current early warning theories of period and amplitude parameters. And, also the advantages and shortcomings about strong earthquake early warning are summarized.(2) Based on the previous studies by others, we give a further study on the relationship between period characters (the instantaneous predominant period τmax and the average period τc) and magnitude within a window of3s after seismic P wave arrival. Then, we fit the formulas about the rapid estimation of magnitude based on period characters. Then, we use the actual data to verify the formulas and the mean squared error is between0.359and0.471. The result meets a certain precision.(3) A method about rapid estimation of magnitude is proposed, which is based on the amplitude parameter of displacement within a window of3s after seismic P arrival. We also fit the formulas about the rapid estimation of peak displacement Pdmax, peak ground acceleration PGA and peak ground velocity PGV.(4) Propose a prediction method which is combined with multi parameters based on the orthogonal experimental design. This method can give a comprehensive prediction for the peak parameters used the formulas which are obtained in this article. And it can also overcome the risk of single information and big dispersion for predicting. Also we use the analysis of range and variance to quantify and contrast the results of prediction. Then, we give an example to test the method for predicting peak displacement and relative error is below3.77%. The result meets a certain precision. At last, several suggestions on the construction of earthquake early warning system are put forward in China and the application of EEW is prospected.