Effects of irregUlar topography on ground motion for incident P, SV and the propagation of Rayleigh waves are studied by combining finite element method with modified transmitting boundary. TheoretiCal models include ...Effects of irregUlar topography on ground motion for incident P, SV and the propagation of Rayleigh waves are studied by combining finite element method with modified transmitting boundary. TheoretiCal models include isolated protrUding topography and similar adjacent Protruding topography. The concluaion drawn from thisstudy is that the effects Of isolated protruding topography are remarkably larger for Rayleigh wave propagation than for P and SV they waves; Considering adjacent irregUlar toography ground motion is amplified, the duration of ground motion becomes longer and the speCtral ratios exhibit narrowband peaks Considering adjacent irregular topography and Rayleigh wave Propagation, the theoretical results wb more approach the results obtained in practice.展开更多
The finite difference method(FDM)is an important numerical approach for simulating the propagation of seismic waves,and some FDMs can be used to study the impact of the Earth’s curvature and topography over large dis...The finite difference method(FDM)is an important numerical approach for simulating the propagation of seismic waves,and some FDMs can be used to study the impact of the Earth’s curvature and topography over large distances.To efficiently model the effects of the Earth’s irregular topography on the propagation of seismic waves,here we optimize a previously proposed grid mesh method and develop a novel two-dimensional boundary-conforming FDM based on a curvilinear polar coordinate system.This method efficiently simulates the propagation of seismic waves in an arc-shaped model with large variations in surface topography.Our method was benchmarked against other reported methods using several global-scale models.The consistency of the results confirms the validity of our proposed optimization strategy.Furthermore,our findings indicate that the proposed optimization strategy improves computational efficiency.展开更多
The pioneer study of simulating the wave field in media with irregular interface belongs to Aki and Lamer. Since that many numerical methods on the subject have been developed, such as pure numerical techniques, ray m...The pioneer study of simulating the wave field in media with irregular interface belongs to Aki and Lamer. Since that many numerical methods on the subject have been developed, such as pure numerical techniques, ray method and boundary method. The boundary method based on boundary integral equation is a semi-analytical method which is suitable to modeling wave field induced by irregular border. According to the property of the applied Green＇s function the boundary methods can be sorted into space domain boundary method and wavenumber domain boundary method. For both of them it is necessary to solve a large equation, which means much computation is needed. Thus, it is difficult for the boundary methods to be applied in simulating wave field with high frequency or in large range. To develop a new method with less computation is meaningful. For this purpose, localized boundary integral equation, i.e., discrete wavenumber method is proposed. It is rooted in the Bouchon-Campillo method, an important wavenumber domain boundary method. Firstly the force on interface is separated into two parts： one is on flat part and the other on irregular part of the interface. Then Fourier transform is applied to identify their relation, the unknown distributes only on irregular part. Consequently computation efficiency is dramatically improved. Importantly its accuracy is the same as that of Bouchon-Campillo.展开更多
文摘Effects of irregUlar topography on ground motion for incident P, SV and the propagation of Rayleigh waves are studied by combining finite element method with modified transmitting boundary. TheoretiCal models include isolated protrUding topography and similar adjacent Protruding topography. The concluaion drawn from thisstudy is that the effects Of isolated protruding topography are remarkably larger for Rayleigh wave propagation than for P and SV they waves; Considering adjacent irregUlar toography ground motion is amplified, the duration of ground motion becomes longer and the speCtral ratios exhibit narrowband peaks Considering adjacent irregular topography and Rayleigh wave Propagation, the theoretical results wb more approach the results obtained in practice.
基金supported by the National Natural Science Foundation of China(No.41790465).
文摘The finite difference method(FDM)is an important numerical approach for simulating the propagation of seismic waves,and some FDMs can be used to study the impact of the Earth’s curvature and topography over large distances.To efficiently model the effects of the Earth’s irregular topography on the propagation of seismic waves,here we optimize a previously proposed grid mesh method and develop a novel two-dimensional boundary-conforming FDM based on a curvilinear polar coordinate system.This method efficiently simulates the propagation of seismic waves in an arc-shaped model with large variations in surface topography.Our method was benchmarked against other reported methods using several global-scale models.The consistency of the results confirms the validity of our proposed optimization strategy.Furthermore,our findings indicate that the proposed optimization strategy improves computational efficiency.
基金supported by National Natural Science Foundation of China (Nos.40874027,90715020 and 90915012)IGPCEA(DQJB07B06)Special Public Welfare Industry (Nos.20070804 and 200808008)
文摘The pioneer study of simulating the wave field in media with irregular interface belongs to Aki and Lamer. Since that many numerical methods on the subject have been developed, such as pure numerical techniques, ray method and boundary method. The boundary method based on boundary integral equation is a semi-analytical method which is suitable to modeling wave field induced by irregular border. According to the property of the applied Green＇s function the boundary methods can be sorted into space domain boundary method and wavenumber domain boundary method. For both of them it is necessary to solve a large equation, which means much computation is needed. Thus, it is difficult for the boundary methods to be applied in simulating wave field with high frequency or in large range. To develop a new method with less computation is meaningful. For this purpose, localized boundary integral equation, i.e., discrete wavenumber method is proposed. It is rooted in the Bouchon-Campillo method, an important wavenumber domain boundary method. Firstly the force on interface is separated into two parts： one is on flat part and the other on irregular part of the interface. Then Fourier transform is applied to identify their relation, the unknown distributes only on irregular part. Consequently computation efficiency is dramatically improved. Importantly its accuracy is the same as that of Bouchon-Campillo.
