Numerical Calculation of Seafloor Synthetic Seismograms Caused by Low Frequency Point Sound Source  

作　　者：LU Zaihua ZHANG Zhihong GU Jiannong 

机构地区：[1]College of Science, Naval University of Engineering

出　　处：《Defence Technology（防务技术）》2013年第2期125-132,共8页Defence Technology

基　　金：Sponsored by National Nature Science Foundation of China ( 51179195);National Defense Foundation of China ( 513030203-02)

摘　　要：Elastic wave on seafloor caused by low frequency noise radiated from ship is called ship seismic wave which can be used to identify ship target. In order to analyze the wave components and the propagating properties of ship seismic wave, the numerical calculation of synthetic seismograms on seafloor aroused by a low frequency point sound source is carried out using a wave number integration technique combined with inverse Fourier transform. According to the numerical example of hard seafloor, the time series of seismic wave on seafloor are mostly composed of interface waves and normal mode waves. Each normal mode wave has a well defined low cut-off frequency, while the interface wave doesn't have. The frequency dispersion of normal mode wave is obvious when frequency is lower than 100Hz, while the interface wave is dispersive only in the infra-sound frequency range. The time series of seismic wave is dominated by the interface wave when the source frequency is less than the minimal cut-off frequency of normal mode wave.Elastic wave on seafloor caused by low frequency noise radiated from ship is called ship seismic wave which can be used to identify ship target. In order to analyze the wave components and the propagating properties of ship seismic wave, the numerical calculation of synthetic seismograms on seafloor aroused by a low frequency point sound source is carried out using a wave number integration technique combined with inverse Fourier transform. According to the numerical example of hard seafloor, the time series of seismic wave on seafloor are mostly composed of interface waves and normal mode waves. Each normal mode wave has a well defned low cut-off frequency, while the interface wave doesn＇t have. The frequency dispersion of normal mode wave is obvious when frequency is lower than 100Hz, while the interface wave is dispersive only in the infra-sound frequency range. The time series of seismic wave is dominated by the interface wave when the source frequency is less than the minimal cut-off frequency of normal mode wave.

关 键 词：maritime engineering low frequency point sound source seismic wave synthetic seismogram numerical calculation 

分 类 号：P738.4[天文地球—海洋地质]