Optimal Fitting Method of Phase Difference Spectrum of Natural Seismic Wave

To ensure that the artificial seismic wave has the characteristics of non-stationary intensity and frequency, it is necessary to generate the artificial peak arrival time that the frequency distribution characteristics meet the requirements by fitting method. The phenomenon of "tail protrusion" exists in the frequency distribution characteristics of peak arrival time of natural seismic waves. Therefore, a method of fitting the frequency distribution characteristics of peak arrival time with normal distribution was proposed, and the normal fitting standard deviation was optimized according to the maximum distribution frequency of peak arrival time of natural seismic waves. 640 natural seismic waves that meet different conditions were selected as research objects. The frequency distribution characteristics of peak arrival time were fitted by normal distribution, lognormal distribution and gamma distribution, respectively. It is found that the frequency distribution characteristics of artificial peak arrival time generated by normal distribution fitting method are most consistent with the frequency distribution characteristics of peak arrival time of natural seismic waves.