(中南工業(yè)大學(xué)地球物理勘察新技術(shù)研究所，長沙 410083；
中國科學(xué)院武漢物理研究所， 武漢 430071)
摘 要: 在三維情況下， 利用B， P， C 坐標(biāo)系研究了水平多層 介質(zhì)中導(dǎo)波的能量分布，提出了一種計算大深度處位移和能流密度的方法，避免了精度丟失問題。 在有低速層介質(zhì)情況 下， 在深入分析瑞利模的基礎(chǔ)上，首次研究了陷模的頻散及能流分布，分析了它們的傳播 機(jī)制 。導(dǎo)波能量可能分布在自由表面附近, 表現(xiàn)為面波; 也可能集中在自由界面下某一深度處， 表現(xiàn)為沿低速層延伸方向傳播的導(dǎo)波。
關(guān)鍵字: 多層介質(zhì) B， P， C坐標(biāo)系 導(dǎo)波 陷模 瑞利波
（Institute of Applied Geophysics,
Central South University of Technology, Changsha 410083, P. R. China
* Wuhan Institute of Physics, Chinese Academy of Sciences, Wuhan 430071, P. R. China）
Abstract:The energy distributions of guided waves in multilayered media have been investigated in three dimensions in B, P, C coordinate system. A method of calculating the displacement and energy flux density at large depth was presented, and the problem of precision loss was avoided. In the case that a low-velocity medium was included, not only was Rayleigh mode analyzed thoroughly, but also the dispersions and energy distributions of trapped modes were studied for the first time, and their mechanisms were analyzed. The energy of guided waves can concentrate possibly in a little area near the free surface, which is corresponding to the surface wave, and it also possibly concentrates in a depth under the free surface, which is corresponding to a guided wave propagation along the stretching direction of the low-velocity formation.
Key words: multilayered media B, P, C coordinate system guided wave
trapped mode Rayleigh wave
