P-Wave Attenuation Relationship And Site Effect For Moderate And Strong Earthquakes

Earthquake early warning is an effective means of earthquake disaster mitigation.P-wave parameters are key parameters in earthquake early-warning systems,such as:using P-wave front 3 seconds displacement peak parameter and its attenuation law for magnitude estimation,and using P-wave superior period for magnitude Estimation is the main method of earthquake early warning magnitude estimation.However,these earthquake magnitude estimation methods all have large discreteness,and do not consider the effects of site effects.Therefore,a comprehensive understanding of the attenuation law of P waves and its site effect has important reference value for earthquake warning magnitude estimation.In this paper,the acceleration records of 11627 groups of strong earthquakes of 278intraplate earthquakes of magnitude 2?6.5 recorded by Ki K-net and K-net network in Japan were collected and screened,and the horizontal and vertical peaks of P waves?Pa,Pv,Pd?and the attenuation relationship of the energy parameter(R_CAV);the variation law of the P-wave superior period???with the magnitude and distance is analyzed;the drilling wave velocity data of 536 stations of Ki K-net network and their corresponding uphole The downhole strong earthquake observation record discusses the field effect of P wave.The following conclusions were obtained:1.Analyze the correlation between the magnitude and distance parameters of the P-wave peak value and energy parameters of the bedrock using the split calibration method.On this basis,determine the P-wave parameters attenuation model and use the random effect regression method to determine The attenuation model coefficients of P wave peak and energy parameters are given.2.The site amplification coefficients of Pa,Pv and R_CAV are significantly related to the equivalent shear wave velocity ratio,and the site amplification coefficient decreases with the increase of the equivalent shear wave velocity ratio,which is in line with the NGA-West site effect on peak acceleration PGA The site amplification model of P;however,the site amplification factor of Pd is not sensitive to the equivalent shear wave velocity ratio;in addition,the site amplification factor decreases as the reference site Pv and Pd increase.3.The P-wave predominant period exhibits significant magnitude-related characteristics and distance-related characteristics.The P-wave predominant period increases with the increase of magnitude and increases with distance.It is worth noting that,relative to the magnitude parameter,the distance parameter has a more significant effect on the P-wave superior period;however,the effect of the soil layer on the P-wave superior period is not obvious.