Identification And Application Of Doppler Effect In Earthquake

At present,the method to determine whether there is Doppler effect in earthquake is not mature.In order to study how to identify Doppler effect in earthquake and its application,this paper proposes to use wavelet transform to identify Doppler effect in earthquake;The fault slip rate is calculated from the Wenchuan earthquake data.The main achievements are as follows:Several stations located in front of the fault slip of the Wenchuan earthquake were selected to perform wavelet transform on the seismic records in the initial period of the station.It was found that with the increase of the epicenter distance,the high-frequency amplitude of the wavelet spectrum was significantly greater than the low-frequency amplitude of the wavelet spectrum,indicating the existence of Doppler effect.Several stations perpendicular to the fault of the Wenchuan earthquake were selected to perform wavelet transform on the seismic records in the initial period of the station.It was found that with the increase of the epicenter distance,the high-frequency amplitude of the wavelet spectrum decreased rapidly,indicating that there was no Doppler effect in this direction.Several improvements have been made to the previous method of calculating fault slip rate by Doppler effect.First,it is proposed to use the relative change of Fourier amplitude standard deviation of seismic waves received by two stations in a certain frequency band to determine whether they are similar;second,Only seismic records of S wave in fault slip time are selected for data processing;third,Short time Fourier transform instead of long time Fourier transform is proposed to improve the accuracy of time location of fault slip rate.The method of calculating fault slip rate by Doppler effect is summarized.The method is used to calculate the fault slip rate of Wenchuan earthquake.The seismic moment release process of the calculation results is basically consistent with the inversion results.It is concluded that the fault slip rate of Wenchuan has the characteristics of sudden change,that is,the slip rate suddenly increases and rapidly decreases.The slip rate is not large in most of the time,and the fault does not slip in some time periods.In this paper,the method of wavelet transform is proposed to identify Doppler effect in earthquake,which has clear physical meaning and theoretical basis in mathematical operation;Using Doppler effect to calculate the fault slip rate,it is unnecessary to master the unclear crustal medium information,the physical meaning of the calculation method is clear,and the obtained parameters are easy to obtain.The calculation of fault slip rate by Doppler effect enriches the calculation theory of fault slip rate.The paper has 40 pictures,2 table and 98 references.