P- and S-wavefield simulations using both the firstand second-order separated wave equations through a high-order staggered grid finite-difference method
Chao-ying Bai1, 2, Xin Wang1, Cai-xia Wang1
1 Department of Geophysics, College of Geology Engineering and Geomatics, Chang’an University, Xi’an 710054, China 2 Institute of Computing Geophysics, Chang’an University, Xi’an 710054, China
P- and S-wavefield simulations using both the firstand second-order separated wave equations through a high-order staggered grid finite-difference method
Chao-ying Bai1, 2, Xin Wang1, Cai-xia Wang1
1 Department of Geophysics, College of Geology Engineering and Geomatics, Chang’an University, Xi’an 710054, China 2 Institute of Computing Geophysics, Chang’an University, Xi’an 710054, China
摘要In seismic exploration, it is common practice to separate the P-wavefield from the S-wavefield by the elastic wavefield decomposition technique, for imaging purposes. However, it is sometimes difficult to achieve this, especially when the velocity field is complex. A useful approach in multi-component analysis and modeling is to directly solve the elastic wave equations for the pure P- or S-wavefields, referred as the separate elastic wave equations. In this study, we compare two kinds of such wave equations: the first-order (velocity–stress) and the secondorder (displacement–stress) separate elastic wave equations, with the first-order (velocity–stress) and the secondorder (displacement–stress) full (or mixed) elastic wave equations using a high-order staggered grid finite-difference method. Comparisons are given of wavefield snapshots, common-source gather seismic sections, and individual synthetic seismogram. The simulation tests show that equivalent results can be obtained, regardless of whether the first-order or second-order separate elastic wave equations are used for obtaining the pure P- or S-wavefield. The stacked pure P- and S-wavefields are equal to the mixed wave fields calculated using the corresponding first-order or second-order full elastic wave equations. These mixed equations are computationally slightly less expensive than solving the separate equations. The attraction of the separate equations is that they achieve separated P- and S-wavefields which can be used to test the efficacy of wave decomposition procedures in multi-component processing. The second-order separate elastic wave equations are a good choice because they offer information on the pure P-wave or S-wave displacements.
Abstract：In seismic exploration, it is common practice to separate the P-wavefield from the S-wavefield by the elastic wavefield decomposition technique, for imaging purposes. However, it is sometimes difficult to achieve this, especially when the velocity field is complex. A useful approach in multi-component analysis and modeling is to directly solve the elastic wave equations for the pure P- or S-wavefields, referred as the separate elastic wave equations. In this study, we compare two kinds of such wave equations: the first-order (velocity–stress) and the secondorder (displacement–stress) separate elastic wave equations, with the first-order (velocity–stress) and the secondorder (displacement–stress) full (or mixed) elastic wave equations using a high-order staggered grid finite-difference method. Comparisons are given of wavefield snapshots, common-source gather seismic sections, and individual synthetic seismogram. The simulation tests show that equivalent results can be obtained, regardless of whether the first-order or second-order separate elastic wave equations are used for obtaining the pure P- or S-wavefield. The stacked pure P- and S-wavefields are equal to the mixed wave fields calculated using the corresponding first-order or second-order full elastic wave equations. These mixed equations are computationally slightly less expensive than solving the separate equations. The attraction of the separate equations is that they achieve separated P- and S-wavefields which can be used to test the efficacy of wave decomposition procedures in multi-component processing. The second-order separate elastic wave equations are a good choice because they offer information on the pure P-wave or S-wave displacements.
基金资助:China National Major Science and Technology Project (Subproject No: 2011ZX05024-001-03)
通讯作者:
Chao-ying Bai
E-mail: baicy@chd.edu.cn
引用本文:
Chao-ying Bai, Xin Wang, Cai-xia Wang. P- and S-wavefield simulations using both the firstand second-order separated wave equations through a high-order staggered grid finite-difference method[J]. 《地震学报》英文版, 2013, 26(2): 83-98.
Chao-ying Bai, Xin Wang, Cai-xia Wang. P- and S-wavefield simulations using both the firstand second-order separated wave equations through a high-order staggered grid finite-difference method. Earthquake Science, 2013, 26(2): 83-98.
