Research On Correlation Between ???? Magnitude Estimation And ???????

Earthquake early warning is one of the effective means to mitigate earthquake disasters.Estimating earthquake magnitude by using initial record information is the core technology of earthquake early warning.Due to the complexity of the rupture process of large earthquakes,the magnitude from early stage record is usually underestimated.For this reason,this paper is to verify the methods presented by foreign experts which use the arrival time of peak ground motion to estimate the magnitude.Based on the systematic summary of the domestic and foreign research present situation,the following research work has been carried out:(1)We analyze the waveforms of the mainshock and three foreshocks of Wenchuan Earthquake and Lushan Earthquake during the initial 30s after P-wave onset to determine the maximum amplitudes of acceleration,velocity,and displacement,and ?c(the period parameter of the waveform).(2)We establish the statistical relationship between the peak arrival time Top(S wave peak arrival time S wave time)with different filtering bands and the magnitude by using 4851 acceleration records of the 605 earthquakes of the strong motion observation network in China.The results show that there is a good linear relationship between the peak arrival timeTop and magnitude of the 8-16Hz filtering band.(3)By using the observation records near the epicenter of the Wenchuan and Lushan earthquakes,the feasibility of applying magnitude estimation is verified.The results show that the magnitude of the estimated magnitude is closer to the true value than the magnitude estimated by the displacement amplitude and period.