(1. 中南大學(xué) 有色金屬成礦預(yù)測(cè)教育部重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410083；
2. 中南大學(xué) 地球科學(xué)與信息物理學(xué)院，長(zhǎng)沙 410083)
摘 要: 從改進(jìn)BISQ模型雙相介質(zhì)所對(duì)應(yīng)的一階速度—應(yīng)力運(yùn)動(dòng)方程出發(fā)，構(gòu)建2×2N階交錯(cuò)網(wǎng)格有限差分模擬算法，為了盡可能地減小或消除數(shù)值模擬中由人工邊界引起的虛假反射，建立完全匹配層(PML)吸收邊界的2×2N階交錯(cuò)網(wǎng)格有限差分算法。詳細(xì)地討論了PML吸收邊界條件的構(gòu)建及其有限差分算法的實(shí)現(xiàn)。通過(guò)MATLAB編程進(jìn)行波場(chǎng)模擬，將加入PML吸收邊界、常規(guī)指數(shù)衰減吸收邊界及未加吸收邊界的3種數(shù)值模擬結(jié)果進(jìn)行對(duì)比，論證PML吸收邊界能十分有效地吸收邊界反射。
關(guān)鍵字: 改進(jìn)BISQ模型；雙相介質(zhì)；有限差分；交錯(cuò)網(wǎng)格；完全匹配層(PML)
seismic waves based on reformulated BISQ model
（1. Key Laboratory of Metallogenic Prediction of Nonferrous Metals, Ministry of Education,
Central South University, Changsha 410083, China;
2. School of Geosciences and Info-Physics, Central South University, Changsha 410083, China）
Abstract:Based on first-order velocity-stress equations of the reformulated BISQ model in double-phase media, the simulation algorithm of finite difference of 2-order time and 2N-order space staggered-grid was built. Meanwhile, in order to minimum effects caused by the artificial boundary in the numerical simulation, the construction of the perfectly matched layer (PML) absorbing boundary condition and the realization of the finite-difference algorithm were discussed in detail. The arithmetic was realized with MATLAB. Compared with the conventional decaying exponential absorbing boundary and the non-absorbing boundary, the PML boundary can more effectively attenuate reflections, which is supported by the wave field modeling.
Key words: reformulated BISQ model; double-phase medium; finite-difference method; staggered-grid; perfectly matched layer (PML)
