Modeling of low-frequency seismic waves in a shallow sea using the staggered grid difference method  

作　　者：卢再华 张志宏 顾建农 

机构地区：[1]College of Science, Naval University of Engineering, Wuhan 430033, China

出　　处：《Chinese Journal of Oceanology and Limnology》2017年第5期1010-1017,共8页中国海洋湖沼学报（英文版）

基　　金：Supported by the National Natural Science Foundation of China(Nos.51179195,51679248);the National Defense Foundation of China(No.513030203-02)

摘　　要：Elastic waves in the seabed generated by low-frequency noise radiating from ships are known as ship seismic waves and can be used to detect and identify ships. To obtain the propagation characteristics of ship seismic waves, an algorithm for calculating Seismic waves at the seafloor is presented based on the staggered-grid finite difference method. The accuracy of the algorithm was tested by comparison with analytical solutions. Numerical simulation of seismic waves generated by a low-frequency point sotmd source in a typical shallow sea environment was carried out. Using various source frequencies and locations in the numerical simulation, we show that the seismic waves in the near field are composed mostly of transmitted S-waves and interface waves while transmitted P-waves are weak near the seafloor. However, in the far field, the wave components of the seismic wave are mainly normal modes and interface waves, with the latter being relatively strong in the waveforms, As the source frequency decreases, the normal modes become smaller and the interface waves dominate the time series of the seismic waves.Elastic waves in the seabed generated by low-frequency noise radiating from ships are known as ship seismic waves and can be used to detect and identify ships.To obtain the propagation characteristics of ship seismic waves,an algorithm for calculating seismic waves at the seafl oor is presented based on the staggered-grid fi nite diff erence method.The accuracy of the algorithm was tested by comparison with analytical solutions.Numerical simulation of seismic waves generated by a low-frequency point sound source in a typical shallow sea environment was carried out.Using various source frequencies and locations in the numerical simulation,we show that the seismic waves in the near fi eld are composed mostly of transmitted S-waves and interface waves while transmitted P-waves are weak near the seafl oor.However,in the far fi eld,the wave components of the seismic wave are mainly normal modes and interface waves,with the latter being relatively strong in the waveforms.As the source frequency decreases,the normal modes become smaller and the interface waves dominate the time series of the seismic waves.

关 键 词：low frequency sound source shallow sea seismic wave staggered grid 

分 类 号：E925[军事—军事装备学] U675.79[兵器科学与技术—武器系统与运用工程]